Balloon Mitral Valvuloplasty in the United States: A 13-Year Perspective

Accepted Manuscript

Balloon Mitral Valvuloplasty in United States: A 13 year perspective

Apurva O. Badheka , M.D Neeraj Shah , M.D Abhijit Ghatak , M.D Nileshkumar J.Patel , M.D Ankit Chothani , M.D Kathan Mehta , M.D Vikas Singh , M.D Nilay Patel ,M.D Peeyush Grover , M.D Abhishek Deshmukh , M.D Sidakpal S. Panaich , M.DGhanshyambhai T. Savani , M.D Vipulkumar Bhalara , M.D Shilpkumar Arora , M.DAnkit Rathod , M.D Harit Desai , M.D Saibal Kar , M.D Carlos Alfonso , M.D Igor F.Palacios , M.D Cindy Grines , M.D Theodore Schreiber , M.D Charanjit S. Rihal ,M.D Raj Makkar , M.D Mauricio G. Cohen , M.D William O'Neill , M.D Eduardo deMarchena , M.D

PII: S0002-9343(14)00401-X

DOI: 10.1016/j.amjmed.2014.05.015

Reference: AJM 12531

To appear in: The American Journal of Medicine

Received Date: 24 March 2014

Revised Date: 13 May 2014

Accepted Date: 13 May 2014

Please cite this article as: Badheka AO, Shah N, Ghatak A, Patel NJ, Chothani A, Mehta K, Singh V,Patel N, Grover P, Deshmukh A, Panaich SS, Savani GT, Bhalara V, Arora S, Rathod A, Desai H,Kar S, Alfonso C, Palacios IF, Grines C, Schreiber T, Rihal CS, Makkar R, Cohen MG, O'Neill W, deMarchena E, Balloon Mitral Valvuloplasty in United States: A 13 year perspective, The American Journalof Medicine (2014), doi: 10.1016/j.amjmed.2014.05.015.

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http://dx.doi.org/10.1016/j.amjmed.2014.05.015

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Balloon Mitral Valvuloplasty in United States: A 13 year perspective

Authors: Apurva O. Badheka M.Da*, Neeraj Shah M.Db*, Abhijit Ghatak M.Dc*, Nileshkumar J Patel

M.Db*, Ankit Chothani M.Dd*, Kathan Mehta M.De*, Nilay Patel M.Da, Vikas Singh M.Dc, Peeyush

Grover M.Dc, Abhishek Deshmukh M.Df, Sidakpal S. Panaich M.Da , Ghanshyambhai T. Savani M.Dc,

Vipulkumar Bhalara M.Da, Shilpkumar Arora M.Da, Ankit Rathod M.Dg, Harit Desai M.Dc, Saibal Kar

M.Dg, Carlos Alfonso M.Dc, Igor F. Palacios M.Dh, Cindy Grines M.Da, Theodore Schreiber, M.Da,

Charanjit S. Rihal M.Di, Raj Makkar M.Dg, Mauricio G. Cohen M.Dc, William O'Neill M.Dj, Eduardo de

Marchena M.Dc.

a: Detroit Medical Center, Detroit, MI; b: Staten Island University Hospital, Staten Island, NY;

c:University of Miami Miller School of Medicine, Miami, FL; d: MedStar Washington Hospital Center,

Washington, DC; e: UPMC Shadyside Hospital, Pittsburgh, PA; f: University of Arkansas for Medical

Sciences, Little Rock, AR; g: Cedars-Sinai Medical Centre, LA, CA; h: Massachusetts General hospital,

Boston, MA; i: Mayo Clinic, Rochester, MN; j: Henry Ford Hospital, Detroit, MI.

* Authors share equal contribution to this manuscript.

Acknowledgment: None declared.

Disclosures: None of the authors have any disclosures relevant to the content of the manuscript.

Funding sources: No study specific funding was used to support this work. The authors are solely

responsible for the study design, conduct and analyses, drafting and editing of the manuscript and its final

contents. No statement should be construed as an official position of the AHRQ or the US Department of

Health and Human Services. All authors had access to the data and a role in writing the manuscript.

Running title: Balloon Mitral Valvuloplasty.

Key Words: Balloon, mitral valve, valvuloplasty, cost, hospital stay, mortality, complications.

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Word Count: 3244

Corresponding Author:

Eduardo De Marchena, MD, F.A.C.C., F.A.C.P

Associate Dean for International Medicine,

University of Miami Miller School of Medicine.

Dominion Towers, 1400 NW 10th Ave, Suite 206A

Miami, Fl33136

Phone: (305) 243 5535

Email: [email protected]

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ABSTRACT

Background: Incidence and prevalence of mitral stenosis is declining in USA. We performed this study

to determine recent trends in utilization, complications, mortality, length of stay and cost associated with

balloon mitral valvuloplasty(BMV).

Methods: Utilizing the nationwide inpatient sample (NIS) database from 1998 to 2010 we identified

patients using the international classification of diseases, 9th Revision, clinical modification (ICD 9-CM)

procedure code for “percutaneous valvuloplasty". Patients≥18 years of age with mitral stenosis were

included. Patients with concomitant aortic, tricuspid or pulmonic stenosis were excluded. Primary

outcome included death and procedural complications.

Results: A total of 1308 balloon mitral valvuloplasty (weighted n= 6540) were analyzed. There was a

7.5% decline in utilization of the procedure from 24.6 procedures/10 million population in 1998-01 to

22.7 procedures/10 million population in 2008-10, (p for trend=0.098).We observed a 15.9% overall

procedural complication rate and 1.7% mortality rate. The procedural complication rates have increased

in recent years (p= 0.001) corresponding to increasing age and burden of comorbidities in patients. The

mean cost per admission for BMV has gone up significantly over the 10 years from $11668 ± 1046 in

2001 to $ 23651 ± 301 in 2010 (p<0.001).

Conclusions: In a large cross sectional study of balloon mitral valvuloplasty in USA, we have reported

trends of decreasing overall utilization and increasing procedural complication rates and cost over a

period of 13 years.

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INTRODUCTION

Since its introduction in 1984,1 Balloon Mitral Valvuloplasty has established itself as the

procedure of choice for patients with severe symptomatic rheumatic mitral stenosis with excellent

immediate, intermediate and long term results.2-9 Although there has been a steady decline in the

incidence of rheumatic heart disease in industrialized nations, rheumatic mitral stenosis still causes

significant mortality and morbidity worldwide. This is especially true in nations with significant numbers

of immigrants from regions with endemic rheumatic heart disease.10

We conducted this study with the aim of examining the trends of over the last decade and study

the effect of hospital and operator procedure volume on outcomes, using the USA’s largest all payer

insurance inpatient database.

METHODS

Data Source:

We analyzed 13 year data (from 1998-2010) of the nationwide inpatient sample (NIS), a subset of

the Healthcare Cost and Utilization Project sponsored by the Agency for Healthcare Research and

Quality (AHRQ). This is the largest publicly available all-payer inpatient care database in the United

States, including 7 to 8 million discharges/year, and is a 20% stratified sample of US community

(nonfederal, short-term, general, and specialty) hospitals. Each individual hospitalization is de-identified

and maintained in the database as a unique entry with 1 primary discharge diagnosis and <14 secondary

diagnosis. Each entry has information on demographic details, insurance status, comorbidities,

procedures, hospitalization outcome, and length of stay with safeguards to protect the privacy of

individual patients, physicians, and hospitals. These data undergo annual quality assessments.

Furthermore, comparisons against the following data sources strengthen the external validity of the

Nationwide Inpatient Sample: the American Hospital Association Annual Survey Database, the National

Hospital Discharge Survey from the National Center for Health Statistics, and the MedPAR inpatient data

from the Centers for Medicare and Medicaid Services.11,12

Study population and design:

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We queried this database from 1998 to 2010 using the International Classification of Diseases, 9th

Revision, Clinical Modification (ICD-9-CM) procedure code designating “Percutaneous Balloon

Valvuloplasty" (ICD-9: 35.96). We included patient ≥18 years of age with mitral stenosis (ICD-9:394.0,

394.2, 396.1, 746.5, 424.0). Patients with concomitant aortic, tricuspid or pulmonic stenosis were

excluded (ICD-9: 395.0, 395.2, 396.0, 396.2, 396.8, 397.0, 397.1, 746.0, 746.1, 746.3, 424.2, 424.3).

Census data was used to determine population estimates of adults ≥18 years of age in order to calculate

the national utilization rates. Since nationwide inpatient sample represents a 20% stratified random

sample of US hospitals17, the population at risk forming the denominator is 20% of the US census

population of adults ≥18 years age for any given year.13 Therefore, utilization rates were calculated by

dividing the number of procedures performed in a given year divided by 20% of the US census

population ≥18 years of age for that year.

We defined severity of comorbid conditions using Deyo modification of Charlson Comorbidity

Index (CCI)15 which contains 17 comorbid conditions with differential weights.(Supplementary table 1)

Preventable procedural complications were identified by Patient Safety Indicators (PSIs) which

have been established by the AHRQ to monitor preventable hospital adverse events. These indicators are

based on ICD-9-CM codes and Medicare severity Diagnosis-Related Groups and each PSI has specific

inclusion and exclusion criteria.14,15 PSI individual technical specifications, were used to identify post-

procedure respiratory failure, post-procedure physiologic and metabolic derangement with acute renal

failure requiring dialysis studied separately, post-procedure pulmonary embolism or deep vein

thrombosis, procedural infectious complications which included post-procedure sepsis and central venous

catheter related bloodstream infection, iatrogenic pneumothorax, complications of anesthesia, pressure

ulcers, and accidental puncture or laceration.16

Other procedure related complications which included hemorrhage requiring blood transfusion,

iatrogenic cardiac complications, implantation of permanent pacemaker implying complete heart block,

pericardial complications, conversion to open heart surgery, other iatrogenic respiratory complications

(which included ventilator associated pneumonia, post-procedure aspiration pneumonia and other

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respiratory complications not elsewhere classified), procedural stroke or transient ischemic attack (TIA)

and vascular complications were identified using ICD-9-CM codes in any secondary diagnosis field

(Supplementary table2). Vascular complications were defined as PSI code for accidental puncture or

ICD-9-CM codes for injury to blood vessels, creation of arteriovenous fistula, injury to

theretroperitoneum, vascular complications requiring surgery and other vascular complications not

elsewhere classified. “Any complications” was defined as occurrence of one or more procedural

complications listed in Table 2.

Hospital and operator procedure volume:

Annual hospital volume was determined using the unique hospital identification number to

calculate the total number of procedures performed by a particular institution in a given year. Hospital

volume and operator volume was incorporated as a continuous variables in the multivariate model in 5

and 3 units per year increments respectively. Two multivariate models were created, one with hospital

volume alone and another incorporating both hospital and operator volume with a term to adjust for

interaction effect between hospital and operator volume. Hospital ID was incorporated as a random effect

in the model to account for the effect of hospital clustering. Of note, operator volume data was available

for only 727 (55.6%) subjects.

Length of stay, Disposition & cost of hospitalization:

The total duration of hospital stay in days was estimated, after excluding in the hospital deaths,

using the length of stay information in the dataset. Disposition was classified into 3 categories: patients

discharged home or with home care services, those discharged to short or long term nursing home or

transferred to another facility and those who died in-hospital.

The Healthcare Cost and Utilization Project (HCUP) contains data on total charges billed by each

hospital. In order to enable users to see how hospital charges translate into actual costs, the HCUP cost-

to-charge ratio files were created. In order to calculate estimated cost of hospitalizations the nationwide

inpatient sample data were merged with cost-to-charge ratios available from HCUP.24 Cost of each

inpatient stay was estimated by multiplying hospital charge with cost-to-charge ratios. Adjusted cost for

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each year was calculated in terms of the 2010 cost, after adjusting for inflation according to the latest

consumer price index (CPI) data. Of note, cost data were available only from 2001 to 2010.

Statistical analysis:

Stata IC 11.0 (Stata-Corp, College Station, TX) and SAS 9.3 (SAS Institute Inc, Cary, North

Carolina) were utilized for analyses. We accounted for complex survey design and clustering in the

analyses using the weights provided for each discharge record in the dataset. Weighted values of patient

level observations were generated to produce a nationally representative estimate of the entire US

population of hospitalized patients. Differences between categorical variables were tested using the chi-

square test and differences between continuous variables were tested using student’s t test. P-value of <

0.05 was considered significant.

Tests for year wise trend:

For categorical variables like utilization rates, procedural complication rates and in-hospital

mortality rates, we used the chi-square test of trend for proportions or Cochrane Armitage test using

‘ptrend’ command in STATA.17,18 For continuous variables like cost and length of stay, we used the non-

parametric test for trend by Cuzick (which is similar to Wilcoxon rank sum test) using the ‘nptrend’

command in STATA.19

Hierarchical modeling:

Hierarchical mixed effects models were generated in order to identify independent multivariate

predictors of in-hospital mortality, procedural complications, length of stay and cost of hospitalization.

Two level hierarchical models (with patient level factors nested within hospital level factors) were

created with the unique hospital identification number incorporated as random effects within the model.

Hierarchical mixed effects logistic regression models were used for categorical dependent variables like

in-hospital mortality and procedural complications and hierarchical mixed effects linear regression

models were used for continuous dependent variables like cost of hospitalization and length of stay.

Variables with >10% missing data were not included in the multivariate models e.g. we excluded race

(27.8% missing data) and admission type (14.8% missing data). In all models, we included hospital level

variables like hospital region (Northeast, South, Midwest with West as referent), teaching vs. non-

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teaching hospital and patient level variables like age, sex, Deyo modification of CCI, use of intra-cardiac

echocardiography (ICE), occurrence of procedural complications, admission over the weekend and

primary payer (with Medicare/Medicaid considered as referent) in addition to hospital/operator procedure

volume. All interactions were thoroughly tested. We assessed multicollinearity using variance inflation

factor (VIF), with VIF greater than 20 suggestive of multicollinearity, and found that none of the

variables were collinear.

RESULTS

Utilization rates:

There were 1308 BMV procedures available for analysis (1998-2010) in patients ≥ 18years,

representing an estimated 6542 procedures in United States over 13 years. The mean age of the patients

was 58.1 ± 15.9 years with majority females (77%). The mean age rose from 58.4 + 16.7 years in 1998 to

62.9 + 17.0 years in 2010 (p for trend<0.001). Although data on race was missing on 27.8% of cases,

among the rest whites constituted the majority (45.5%) (Table1). The mean Charlson (CCI) score for the

cohort was calculated as 0.8 ± 1.1 (0.6+ 1.2 in 1998 to 1.5+ 1.5 in 2010 p for trend<0.001). Most of the

admissions for the procedure (95.8%) were over the weekdays with majority been done electively

(53.4%) with majority in urban teaching hospitals (>90%). There was a 7.5% decline in utilization of the

procedure from 24.60 procedures/10 million population in 1998-01 to 22.76 procedures/10 million

population in 2008-10 (p trend =0.09)(Figure 1).

Mortality:

Among 1308 procedures, we reported 23 (crude mortality rate-1.7%) deaths. Increasing age

(OR1.71 for every 10 year increase in age, 95% CI 1.08-2.72, p=0.022) and occurrence of any procedural

complication (OR 22.19, 95% CI 6.06-81.16, p<0.001) were independent predictors of mortality. The

overall crude mortality rate was consistent across 1998 to 2007 (average mortality rate from 1998-2007

was 1.36%); however there was a significant increase in the mortality rate from 2008-2010 (mortality rate

from 2008-10 was 2.61%), p=0.001. This is in conjunction with the increase in the mean age and means

CCI score (Figure 2).

Complications:

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The incidence of procedural complication rate was 15.9% (Table 2). Vascular adverse events

accounted for 2.7% of these procedural complications. (Table 2 and Supplementary table 2). Cardiac

complications occurred in 4.5% of these cases with majority been coded as iatrogenic cardiac

complications (2.7%). Complete heart block requiring permanent pacing (<0.5%) and pericardial

tamponade (0.6%) accounted for rest. The ICD-9 codes for the individual categories are reported in

Supplementary table 2. During admission, 5.8% patients required open heart surgery. Respiratory

complications included pneumothorax (<0.5%), post-operative respiratory failure (1.9%) and other

iatrogenic respiratory complications (<0.5%). Post-procedure neurological events (stroke or TIA)

accounted for 2.8% of complications. Remaining procedural complications were coded as renal and

metabolic complications (<0.5%), post-procedure deep vein thrombosis or pulmonary embolism (0.8%),

post-op infectious complications (0.8%), and pressure ulcers (0.7%).

As illustrated in Table 3, increasing CCI was an independent predictor of the combined endpoint

of procedural complications and death. Increase in operator volume was an independent predictor of

decreased risk of death and procedural complications (HR 0.39 for every 3 unit increase in the operator

volume, p=0.001) or complications (HR 0.42 for every 3 units increase in the operator volume, p=0.002).

Increasing hospital volume showed statistically non-significant trends towards decreased combined end

points. (Supplementary table 3).

Overall, there was annual 0.4% (p=0.001) increase in the procedural complication rate from 1998 to 2010

correlating with simultaneous rise in age and mean CCI score over the study period (Figure 2).

Length of stay, disposition and cost:

The mean length of stay (±SE) for patients discharged alive was 3.9 ± 0.2 days. Any

complication during the procedure (+6.87 days, 95% CI 5.41-8.33 days, p<0.001), weekend admissions

(+4.86 days, 95% CI 2.59-7.12 days, p=0.001) were strongly predictive of extended length of stay (Table

3). On the contrary, increase in operator volume was associated with reduced length of stay. Similar to

the combined model, in the hospital volume only model, increase in hospital volume although showed a

non-significant trend towards decreasing length of stay (Supplementary table 3).

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The mean length of stay in 1998 was significantly higher as compared to 2010 (5.30± 0.70 days

vs. 3.92 ± 0.45 days, p=0.001) (Figure3). As shown in Table 1, most of the patients (86.8%) were

discharged with only 5.8% requiring disposition to assisted facilities.

As illustrated in Table 1, medicare and medicaid were the primary payers for the procedure

(46.9%). The cost data were available for only 423 procedures (which corresponds to 2115 weighted

procedures), from 2001-2010. The mean cost per admission for the procedure has gone up significantly

(Figure 4) {2001: $11,668 ± 1046 vs. 2010: $23,651 ±308, p<0.001}.The only independent predictor of

increased cost of hospitalization (in the model with both operator and hospital volume) was occurrence of

any procedural complications (Table3). In the hospital volume model, weekend admissions were also

predictive of increased cost of hospitalization (Supplementary table3).

DISCUSSION

Our study represents one of the largest studies to summarize the overall trends of balloon mitral

valvuloplasty over a 13 year period from 1998-2010. We observed a slow and steady decline in the

utilization of procedure representing the overall gradual decline in mitral stenosis in USA and a shift in

the paradigm of utilization towards patients with increasing age and comorbidities. The demographics of

the patients included in our study are markedly different as compared to those from developing

nations.20,21 In addition to a higher percentage of females in our study, the mean age and the underlying

comorbidities of patients undergoing BMV were higher and comparable to previous studies.3,22,23 This

data is in conjunction with the NHLBI24 registry where mortality rate was highest among patients above

70 years of age which usually implies unfavorable valve anatomy and increase in the comorbidities.

Complications:

In prior studies10,23-26 mortality rates of 0-3% have been reported and are usually related to

vascular complications, hemopericardium and shock. We report an in-patient mortality rate of 1.7%

significantly associated with occurrence of any procedural complications, and increasing age.

The overall procedural complication rate was 15.9% of patients admitted for the procedure. The

overall procedural complication rates are slightly higher than those reported in the NHLBI24 registry

(12%) which had a similar heterogeneous patient distribution. This difference in the complication rate is

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related to reporting of an comparatively more exhaustive list of complications, as identified by PSI and

ICD-9 CM codes in patients with advanced age and significant comorbidities. The percentage of patients

with post-op hemorrhage requiring transfusion in our series was similar to those reported by Nobuyoshi

et al (2%)26 in their series of 106 patients. Similar rates (1%) of vascular complications have been

reported in the in the NHLBI registry albeit with a much higher rate of transfusion requirement (8.5%).

Cardiac complications: The incidence of cardiac tamponade/requirement for urgent

pericardiocentesis has been reported in up to 4-7% of the procedures in prior studies.24,25 In our study

pericardial complications occurred only in 0.6% of the cases which could partly be attributed to a certain

proportion of patients with cardiac tamponade being coded under either “iatrogenic cardiac

complications” or “requiring open heart surgery”. Episodes of complete heart block as reported in our

study are uncommon during the procedure and are usually related to trauma incurred by the conduction

system either during the trans-septal puncture or balloon dilatation. We report a 5.8% rate of cardiac

surgery during the admission which are comparable to prior study (4-6.7%)24,25 and likely related to peri-

procedural complications.

Left atrial (LA) or left atrial appendage (LAA) thrombus formation is not uncommon in patients

with mitral stenosis despite warfarin therapy27 and intra-procedural strokes are usually secondary to

embolization from the catheters, wires, and dislodgement of a intracardic thrombus stroke rates of up to

2%24 has been reported in the past and are usually higher in elderly patients with calcified valves and

increased comorbidities.28 The rates of neurological complications in our study (2.8%) are in keeping

with those reported in the literature.24,28 Utilization of imaging especially TEE or ICE prior to the

procedure to document absence of intracardiac thrombus is mandatory per the ACC/AHA guidelines29.

We observed the use of ICE in only 4% of the cases. Use of the same ICD-9 codes identifying

transthoracic and TEE precluded any comment on use of TEE. Post procedural respiratory complications

are usually secondary to worsening mitral regurgitation leading to pulmonary edema. Our rates of post-

operative respiratory failure of 2% are slightly lower than previously reported peri-procedural intubation

rates of up to 3.8% by the NHLBI registry.24

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The overall increase in the complication rate as observed from 1998 to 2010 may be explained by

the simultaneously increasing trend in age and comorbidity burden. In addition, the overall decline in

rheumatic heart disease and utilization of the procedure over the years, may lead to decreased annual

operator volume possibly accounting for the increased trend in complications. We observed that the

average annual operator volume declined from (mean + SE) 2.8 + 0.4 in 1998 to 1.6+0.1 in 2009

(p=0.003).

We have demonstrated increasing operator volume to be independently predictive of favorable

outcomes. Similar association of reduced complications, increased technical success and improved

outcome with increasing operator volume has been reported in the literature.30-32 Although increased

hospital procedural volume did not reach statistical significance in our report, it showed a favorable trend

towards reducing complication rates, supporting the conclusions from the NHLBI registry.24

In keeping with these trends our data supports recently updated guidelines29 on valvular heart

disease strongly recommend that mitral valvuloplasty should be performed in higher volume centers with

skilled and experienced operators. As the utilization rate of BMV is gradually decreasing over years,

these centers would not only play a pivotal role in reducing the complication rates, but would also be

indispensable towards providing and maintaining adequate volume required for training physicians.

Length of stay, disposition and cost:

Length of stay reported in our cohort was comparable to that reported in the NHLBI data

(3.6±6.8 days). Patients admitted over the weekend and those experiencing any procedural complications

had extended stay. Increasing operator volume translated into reduced length of stay. Post procedure most

of these patients were discharged home with only a very small proportion of patients going to another

facility. We observed a significant rise in the cost for in-hospital care for patients over study period

without any significant change in the mean stay. This could largely be secondary to advanced age along

with an increase in the burden of comorbidities and the associated cost of management of chronic illness

in patients.

Limitations:

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Our study has several important limitations, which are inherent to administrative databases. It is

possible that procedure volume was misrepresented by the sample. Similarly, we identified complications

using the standardized ICD-9 and PSI codes which may not cover all procedural complications. Although

principal diagnosis is accurately coded in administrative data, secondary or comorbid diagnoses are often

under-reported. The operator volume data could be misrepresented as operators could be performing the

procedure in hospitals, which were not part of the database. We observed a decreasing trend of missing

secondary diagnoses from 1998 to 2010 (9.7% vs. 1.1%, p<0.001). More complete data entry with

increased reporting of the comorbid conditions over the years may be the sole reason for the observed

trend of increase in the Charlson comorbidity index over the years, which is a possible limitation of our

study.

In conclusion, there has been a very steady, albeit statistically non-significant, trend of decline in

utilization of balloon mitral valvuloplasty in US in concordance with the downward trend in incidence of

mitral stenosis. The procedure is increasingly being performed on patients with higher comorbidities and

increasing age. Operator experience significantly reduces the risk of death and procedural complications

and plays a pivotal role in reducing the overall length of stay and indirectly influences the cost

effectiveness of the procedure.

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REFERENCES

1. Inoue K, Owaki T, Nakamura T, Kitamura F, Miyamoto N. Clinical application of transvenous mitral

commissurotomy by a new balloon catheter. The Journal of thoracic and cardiovascular surgery

1984;87:394-402.

2. Abascal VM, Wilkins GT, O'Shea JP, Choong CY, Palacios IF, Thomas JD, Rosas E, Newell JB,

Block PC, Weyman AE. Prediction of successful outcome in 130 patients undergoing percutaneous

balloon mitral valvotomy. Circulation 1990;82:448-456.

3. Multicenter experience with balloon mitral commissurotomy. NHLBI Balloon Valvuloplasty Registry

Report on immediate and 30-day follow-up results. The National Heart, Lung, and Blood Institute

Balloon Valvuloplasty Registry Participants. Circulation 1992;85:448-461.

4. Iung B, Nicoud-Houel A, Fondard O, Hafid A, Haghighat T, Brochet E, Garbarz E, Cormier B, Baron

G, Luxereau P, Vahanian A. Temporal trends in percutaneous mitral commissurotomy over a 15-year

period. European heart journal 2004;25:701-707.

MANUSCRIP

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15

5. Palacios IF, Block PC, Wilkins GT, Weyman AE. Follow-up of patients undergoing percutaneous

mitral balloon valvotomy. Analysis of factors determining restenosis. Circulation 1989;79:573-579.

6. Dean LS, Mickel M, Bonan R, Holmes DR, Jr., O'Neill WW, Palacios IF, Rahimtoola S, Slater JN,

Davis K, Kennedy JW. Four-year follow-up of patients undergoing percutaneous balloon mitral

commissurotomy. A report from the National Heart, Lung, and Blood Institute Balloon Valvuloplasty

Registry. Journal of the American College of Cardiology 1996;28:1452-1457.

7. Trevino AJ, Ibarra M, Garcia A, Uribe A, de la Fuente F, Bonfil MA, Feldman T. Immediate and long-

term results of balloon mitral commissurotomy for rheumatic mitral stenosis: comparison between Inoue

and double-balloon techniques. American heart journal 1996;131:530-536.

8. Pavlides GS, Nahhas GT, London J, Gangadharan C, Troszak E, Barth-Jones D, Puchrowicz-Ochocki

S, O'Neill WW. Predictors of long-term event-free survival after percutaneous balloon mitral

valvuloplasty. The American journal of cardiology 1997;79:1370-1374.

9. Fawzy ME, Fadel B, Al-Sergani H, Al Amri M, Hassan W, Abdulbaki K, Shoukri M, Canver C. Long-

term results (up to 16.5 years) of mitral balloon valvuloplasty in a series of 518 patients and predictors of

long-term outcome. Journal of interventional cardiology 2007;20:66-72.

10. Nobuyoshi M, Arita T, Shirai S, Hamasaki N, Yokoi H, Iwabuchi M, Yasumoto H, Nosaka H.

Percutaneous balloon mitral valvuloplasty: a review. Circulation 2009;119:e211-219.

11. http://www.hcup-us.ahrq.gov/db/nation/nis/nisrelatedreports.jsp.

12. Epstein AJ, Polsky D, Yang F, Yang L, Groeneveld PW. Coronary revascularization trends in the

United States, 2001-2008. JAMA : the journal of the American Medical Association 2011;305:1769-1776.

13. U.S. Census Bureau - Population Division. Annual estimates of the resident population by sex and

selected age groups for the United States: April 1, 2000 to July 1, 2009 (NC-EST2009-02) [Accessed

March 2, 2011]; .

14. McDonald KM, Romano PS, Geppert J, Davies SM, Duncan BW, Shojania KG, Hansen A. Measures

of Patient Safety Based on Hospital Administrative Data - The Patient Safety Indicators. Rockville (MD),

2002.

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15. Romano PS, Geppert JJ, Davies S, Miller MR, Elixhauser A, McDonald KM. A national profile of

patient safety in U.S. hospitals. Health Aff (Millwood) 2003;22:154-166.

16. http://www.qualityindicators.ahrq.gov/modules/PSI_TechSpec.aspx.Accessed March 2, 2011.

17. Murphy MM, Ng SC, Simons JP, Csikesz NG, Shah SA, Tseng JF. Predictors of major complications

after laparoscopic cholecystectomy: surgeon, hospital, or patient? Journal of the American College of

Surgeons 2010;211:73-80.

18. Armitage P. Tests for Linear Trends in Proportions and Frequencies.

19. Cuzick J. A Wilcoxon-type test for trend. Statistics in medicine 1985;4:87-90.

20. Carroll JD, Feldman T. Percutaneous mitral balloon valvotomy and the new demographics of mitral

stenosis. JAMA : the journal of the American Medical Association 1993;270:1731-1736.

21. Joswig BC, Glover MU, Handler JB, Warren SE, Vieweg WV. Contrasting progression of mitral

stenosis in Malayans versus American-born Caucasians. American heart journal 1982;104:1400-1403.

22. Herrmann HC, Wilkins GT, Abascal VM, Weyman AE, Block PC, Palacios IF. Percutaneous balloon

mitral valvotomy for patients with mitral stenosis. Analysis of factors influencing early results. The

Journal of thoracic and cardiovascular surgery 1988;96:33-38.

23. Palacios I, Block PC, Brandi S, Blanco P, Casal H, Pulido JI, Munoz S, D'Empaire G, Ortega MA,

Jacobs M, et al. Percutaneous balloon valvotomy for patients with severe mitral stenosis. Circulation

1987;75:778-784.

24. Complications and mortality of percutaneous balloon mitral commissurotomy. A report from the

National Heart, Lung, and Blood Institute Balloon Valvuloplasty Registry. Circulation 1992;85:2014-

2024.

25. Herrmann HC, Kleaveland JP, Hill JA, Cowley MJ, Margolis JR, Nocero MA, Zalewski A, Pepine

CJ. The M-Heart percutaneous balloon mitral Valvuloplasty Registry: initial results and early follow-up.

The M-Heart Group. Journal of the American College of Cardiology 1990;15:1221-1226.

26. Nobuyoshi M, Hamasaki N, Kimura T, Nosaka H, Yokoi H, Yasumoto H, Horiuchi H, Nakashima H,

Shindo T, Mori T, et al. Indications, complications, and short-term clinical outcome of percutaneous

transvenous mitral commissurotomy. Circulation 1989;80:782-792.

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27. Shaw TR, Northridge DB, Sutaria N. Mitral balloon valvotomy and left atrial thrombus. Heart

2005;91:1088-1089.

28. Shaw TR, Sutaria N, Prendergast B. Clinical and haemodynamic profiles of young, middle aged, and

elderly patients with mitral stenosis undergoing mitral balloon valvotomy. Heart 2003;89:1430-1436.

29. Bonow RO, Carabello BA, Chatterjee K, de Leon AC, Jr., Faxon DP, Freed MD, Gaasch WH, Lytle

BW, Nishimura RA, O'Gara PT, O'Rourke RA, Otto CM, Shah PM, Shanewise JS. 2008 Focused update

incorporated into the ACC/AHA 2006 guidelines for the management of patients with valvular heart

disease: a report of the American College of Cardiology/American Heart Association Task Force on

Practice Guidelines (Writing Committee to Revise the 1998 Guidelines for the Management of Patients

With Valvular Heart Disease): endorsed by the Society of Cardiovascular Anesthesiologists, Society for

Cardiovascular Angiography and Interventions, and Society of Thoracic Surgeons. Circulation

2008;118:e523-661.

30. Iung B, Cormier B, Ducimetiere P, Porte JM, Nallet O, Michel PL, Acar J, Vahanian A. Immediate

results of percutaneous mitral commissurotomy. A predictive model on a series of 1514 patients.

Circulation 1996;94:2124-2130.

31. Hung JS, Lau KW, Lo PH, Chern MS, Wu JJ. Complications of Inoue balloon mitral

commissurotomy: impact of operator experience and evolving technique. American heart journal

1999;138:114-121.

32. Rihal CS, Nishimura RA, Holmes DR, Jr. Percutaneous balloon mitral valvuloplasty: the learning

curve. American heart journal 1991;122:1750-1756.

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FIGURE TITLES AND LEGENDS

Figure 1: Utilization trends for Balloon Mitral Valvuloplasty per 10 million populations from 1998

2010.

Figure 2: Trends in procedural complication and mean Charlson/Deyo score for BMV 1998-2010.

CCI: Charlson comorbidity index

Figure 3: Length of stay & Cost trends for BMV admission from 2001-2010.

Figure 4: Utilization cost (in dollars) & complications trends adjusted for 2010 for BMV from

2001-2010.

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Table 1: Demographics of the study population undergoing BMV procedure in the

United States over the study period of 13 years from 1998-2010.

Actual (projected) number of BMV procedure in the United States 1308(6542)

Patient characteristics

Age 58.2 ± 16.0

Male (%) 23.5

Race* (%)

White 45.6

Non-white 26.6

Comorbidities† (%)

Charlson/Deyo comorbidity index‡ 0.8 ± 1.1

Obesity 5.2

History of hypertension 38.9

History of diabetes 13.2

History of congestive heart failure 4.6

History of chronic pulmonary disease 18.9

Pulmonary circulatory disorder 0.9

Peripheral vascular disease 4.8

Fluid-electrolyte abnormalities and or renal failure 10.2

Paralysis or other neurological disorder 4.3

Chronic anemia or presence of any coagulopathy 12

Hematological or oncological malignancy 2.2

Weight loss/cachexia 0.9

Rheumatoid arthritis or other collagen vascular disease 1.9

Depression, psychosis alcohol or any other drug abuse 6

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Median household income

category for patient's zip code§

1. 0-25th percentile 16.5




Primary Payer (%)

Medicare / Medicaid 47.2

Private including HMO 43.2

Self pay/no charge/other 9.6

Hospital characteristics

Hospital bed size (%)

Small 5.5

Medium 10.5

Large 84.0

Urban hospitals (%) 99.1

Hospital region (%)

Northeast 29.7

Midwest or North Central 21.4

South 22.9

West 26.0

Teaching hospitals (%) 90.6

Emergent/ urgent admission (%) 31.8

Weekend admission (%) 4.2

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Other major cardiac procedures performed

during hospitalization (ICD 9 procedure code) (%)

Coronary angiography (88.55, 88.56) 42.6

Percutaneous coronary intervention (36.06, 36.07) 1.7

Intraaortic balloon pump (37.68,37.62) 1.5

Left ventricular assist device (37.68,37.62) <0.5%

Morbidity, mortality, cost and outcome

Length of stay(Means ± SE) 3.92 ± 0.2

Total charges# ($)(Means ± SE) 20,499 ± 886

Disposition

Home 92.5

Facility 5.8

Death 1.7

* Race was missing in 27.8% of the patient population.

† Variables are AHRQ comorbidity measures, which were available for year 2002 -2010 (n =

900).

‡ Charlson/Deyo comorbidity index was calculated as per Deyo classification.

§ This represents a quartile classification of the estimated median household income of

residents in the patient's ZIP Code. These values are derived from ZIP Code-demographic

data obtained from Claritas. The quartiles are identified by values of 1 to 4, indicating the

poorest to wealthiest populations. Because these estimates are updated annually, the value

ranges vary by year. http://www.hcupus.ahrq.gov/db/vars/zipinc_qrtl/nisnote.jsp

|| Admission type was missing in 14.8% of the population.

# For each year, cost was adjusted for inflation according to reference 2010 cost. Cost was

missing in 27.2% cases.

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Table 2: Adverse clinical events related to Balloon Mitral Valvuloplasty by ICD-9 code,

over 13 years (1998-2010).

Adverse Clinical Events (ACE) Percentage

Death 1.7

Death or any procedural complications 16.3

Any procedural complications 15.9

Vascular complications 2.7

1) Post-op hemorrhage requiring transfusion* 1.6

2) Other vascular complications† 1.3

Cardiac complications 4.5

1) Iatrogenic cardiac complications 2.7

2) Complete heart block‡ <0.5

3) Pericardial complications 0.6

Requiring open heart surgery 5.8

Respiratory complications 2.2

1) Pneumothorax <0.5

2) Post-op respiratory failure 1.9

3) Other iatrogenic respiratory complications <0.5

Neurological Complications

Post-op Stroke/TIA 2.8

Renal and metabolic complications <0.5

1) Acute renal failure requiring dialysis <0.5

2) Acute severe metabolic derangement <0.5

Postoperative DVT or pulmonary embolism§ 0.8

Postoperative infectious complications 0.8

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Pressure ulcer rate 0.7

Anesthetic complications 0.0

* Hemorrhage requiring transfusion was identified as having any patient having post-

operative hemorrhage and also got transfusion.

† Details in supplementary Table 2.

‡ ICD-9 codes for permanent pacemaker were used to identify post procedure patients with

complete heart block.

§ Infectious complications were identified as composite of post-operative sepsis, septic shock

or catheter related infection.

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Table 3: Multivariate predictors of complications, mortality length of stay and cost of

hospitalization for BMV (operator + hospital volume model).*

Variables OR with 95% CI P value

Any procedural complications and death† (n=727)

Deyo modification of CCI‡ (0=ref)

1 2.80 (1.64-4.79) <0.001

2+ 6.00 (3.38-10.67) <0.001

Operator volume (3 unit increase) 0.39 (0.23-0.68) 0.001

Hospital volume (5 unit increase) 0.82 (0.64-1.04) 0.105

Procedural complication† (n=727)

Deyo modification of CCI‡(0=ref)

1 2.82 (1.64-4.86) <0.001

2+ 5.95 (3.32-10.67) <0.001

Operator volume (3 unit increase) 0.42 (0.24-0.73) 0.002


Length of stay† (n=707) Estimate (days) P value

Any complication +6.87 (5.41-8.33) <0.001

Weekend admission +4.86 (2.59-7.12) 0.001

Private insurance -1.58 (-2.76 to -0.39) 0.009

Operator volume (3 unit increase) -1.31(-2.49 to -0.12) 0.030

Hospital volume (5 unit increase) +0.03 (-0.65 to 0.71) 0.930

Cost of hospitalization§† Estimate ($) P value

Any complication +28440 (21621-35260) <0.001

Weekend admission +8801 (-1388 to 18991) 0.09

Operator volume (3 unit increase) -897 (-6383 to 4590) 0.749

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Hospital volume (5 unit increase) +1149 (-2142 to4440) 0.494

We could not analyze the entire study population due to limited availability of operator ID for

all hospitals in HCUS NIS dataset.

* Apart from cost of hospitalization data rest of the data is from 1998-2010.

† Variables included for the multivariable analysis included age (in 10 years increment),

gender, any procedural complications, use of intra-cardiac echocardiography (ICE), Deyo

modification of CCI, Operator volume (3 unit increase), Weekend admission, primary payer,

teaching hospital, hospital regions (South, North-East, Mid-West, West), and Hospital

volume in 5 unit increments.

‡ CCI denotes Charlson comorbidity index

§ Cost data were recorded beginning 2001 and hence we have information on hospitalization

cost from 2001 to 2010 only. For each year, cost was adjusted for inflation according to the

2010 value. (http://www.usinflationcalculator.com).

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Figure 1: Utilization trends for Balloon Mitral Valvuloplasty per 10 million population

from 1998 2010.

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Figure 2: Trends in procedural complication and mean Chalson Deyo score for BMV 1998-

2010.

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Figure 3: Length of stay & cost trends for BMV admission from 2001-2010.

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Figure 4: Utilization cost (in dollars) & complications trends adjusted for 2010 for BMV

from 2001-2010.

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Clinical Significance:

• Utilization of balloon mitral valvuloplasty (BMV) declined by 7.5% in the last decade (p for

trend=0.098).

• The procedural complication rates have increased in recent years (p= 0.001) corresponding to

increasing age and burden of comorbidities in patients undergoing this procedure.

• The mean cost per admission for BMV has significantly increased from $11,668 ± 1,046 in 2001

to $ 2,3651 ± 301 in 2010 (p<0.001).

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Supplementary table 1: Deyo modification of Charlson comorbidity index (CCI).

Reported ICD-9 CM Codes Condition Charlson Score

410 – 410.9 Myocardial infarction 1

428 – 428.9 Congestive heart failure 1

433.9, 441 – 441.9, 785.4, V43.4 Peripheral vascular disease 1

430 – 438 Cerebrovascular disease 1

290 – 290.9 Dementia 1

490 – 496, 500 – 505, 506.4 Chronic pulmonary disease 1

710.0, 710.1, 710.4, 714.0 – 714.2,

714.81, 725

Rheumatologic disease 1

531 – 534.9 Peptic ulcer disease 1

571.2, 571.5, 571.6, 571.4 – 571.49 Mild liver disease 1

250 – 250.3, 250.7 Diabetes 1

250.4 – 250.6 Diabetes with chronic

complications

2

344.1, 342 – 342.9 Hemiplegia or paraplegia 2

582 – 582.9, 583 – 583.7, 585, 586, 588 –

588.9

Renal disease 2

140-172.9, 174-195.8, 200-208.9 Any malignancy including

leukemia and lymphoma

2

572.2 – 572.8 Moderate or severe liver disease 3

196-199.1 Metastatic solid tumor 6

042 – 044.9 AIDS 6

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Supplementary table 2: Procedural complications of BMV by ICD 9 code.

Any procedural complications ICD CODE

Vascular complications

1) Post-op hemorrhage requiring

transfusion

99.0

2) Vascular complications including -Injury to blood vessels-900-904

-Accidental puncture-998.2, e8700-8709 (PSI)

-AV fistula-447

-Injury to retro-peritoneum 8680.4

-Vascular complications requiring surgery-39.31,

39.41, 39.49, 39.52, 39.53, 39.56, 39.57, 39.58,

39.59, 39.79

-Other vascular complications-999.2, 997.7

Cardiac complications

1) Iatrogenic cardiac complications 997.1*

2) Complete heart block 37.71, 37.73, 37.81, 37.82, 37.83, 0051,v450.1

3) Pericardial complications 423.0-Hemopericardium

423.3-Cardiac tamponade

37.0-Pericardiocentesis

37.12-Pericardiotomy or pericardial window

Requiring open heart surgery 35.10, 35.11, 35.12, 35.13, 35.14,

35.20, 35.21, 35.22, 35.23, 35.24, 35.25, 35.26,

35.27, 35.28, 35.32, 35.33,35.34, 35.35,35.42,

35.50, 35.51, 35.52, 35.53, 35.54,

35.60, 35.61, 35.62, 35.63,

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35.70, 35.71, 35.72, 35.73,

35.81, 35.82, 35.83, 35.84,

35.91, 35.92, 35.93, 35.94, 35.95, 35.97, 35.98,

35.99, 36.31, 36.32, 37.32, 37.33, 37.34, 37.35,

37.51, 37.52, 37.53, 37.54

Respiratory complications

1) Pneumothorax 512.1

2) Post-op respiratory failure PSI†

3) Other iatrogenic respiratory

complications

997.3

Neurological complications

Postoperative-stroke/TIA 997.0, 997.00, 997.01, 997.02, 435.9,

438.0, 4381.0,

4381.1, 4381.2, 4381.9,

4382.0, 4382.1, 4382.2,

4383.0, 4383.1, 4383.2, 4384.0, 4384.1, 4384.2,

4385.0, 4385.1, 4385.2, 4385.3

4388.1, 4388.2, 4388.9, 438.9

Renal and metabolic complications

1) Acute renal failure requiring dialysis PSI†

2) Acute severe metabolic derangement PSI†

Postoperative DVT or pulmonary

embolism.

PSI†

Postoperative infectious complications PSI†

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*997.1Iatrogenic cardiac complications

• Av block 3rd degree, complication of av nodal ablation

• Av block, complete, post op complication of av nodal ablation

• Bypass complications

• Cardiac arrest as a complication of care

• Cardiac arrest during and/or resulting from a procedure

• Cardiac complication

• Cardiac complication of procedure

• Cardiac insufficiency as a complication of care

• Cardiac insufficiency during and/or resulting from a procedure

• Cardiorespiratory failure as a complication of care

• Cardiorespiratory failure during and/or resulting from a procedure

• CHF after surgery, early postop complication

• CHF following cardiac surgery, postop

• CHF following non-cardiac surgery, postop

• Complete atrioventricular block due to atrioventricular nodal ablation

• Congestive heart failure after surgery

• Congestive heart failure as early postoperative complication

• Congestive heart failure as postoperative complication of cardiac surgery

• Congestive heart failure as postoperative complication of non cardiac surgery

• Heart failure as a complication of care

• Junctional ectopic tachycardia, postoperative

• Post cardiac operation functional disturbance

• Postoperative cardiac complication

• Postoperative complete heart block

• Postoperative his bundle tachycardia

• Postoperative myocardial infarction

• Postoperative sinoatrial disease

• Postoperative subendocardial myocardial infarction

• Postoperative transmural myocardial infarction of anterior wall

Pressure ulcer rate PSI†

Anesthetic complications PSI†

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• Postoperative transmural myocardial infarction of inferior wall

• Recurrent coronary arteriosclerosis after percutaneous transluminal coronary angioplasty

997.1 Excludes

• the listed conditions as long-term effects of cardiac surgery or due to the presence of cardiac prosthetic device ( 429.4)

Applies To

• Cardiac:

o arrest during or resulting from a procedure

o insufficiency during or resulting from a procedure

• Cardiorespiratory failure during or resulting from a procedure

Heart failure during or resulting from a procedure

†Post-procedural complications were identified by Patient Safety Indicators (PSIs) which have been established by the Agency for

Healthcare Research and Quality to monitor preventable adverse events during hospitalization. These indicators are based on ICD-9-CM

codes and Medicare severity Diagnosis-Related Groups and each PSI has specific inclusion and exclusion criteria PSI individual measure

technical specifications, Version 4.4, March 2012 was used to identify and define preventable complications.

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Supplementary table 3: Multivariate predictors of complications, mortality length of

stay and cost of hospitalization for BMV (hospital volume model).*

Variables OR with 95% CI P value

Any procedural complications and

death†(n=1303)


1 2.76 (1.87-4.09) <0.001

2+ 5.62 (3.67-8.60) <0.001

Female gender 0.66 (0.46-0.94) 0.021


Procedural complications†:(n=1303)

Deyo modification of CCI‡(0=ref)

1 2.80 (1.88-4.15) <0.001

2+ 5.50 (3.59-8.45) <0.001

Female gender 0.70(0.50-1.02) 0.062


Length of stay†: (n=1270) Estimate (days) P value

Any complication +6.38 (5.40-7.37) <0.001


1 +0.96 (0.14-1.78) 0.022

2+ +1.98 (0.99-2.98) <0.001

Weekend admission +4.83 (3.12-6.54) <0.001

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Private insurance -1.52 (-2.34 to -0.7) <0.001

Hospital volume (5 unit increase) -0.31 (-0.66 to 0.05) 0.09

Cost of hospitalization§†:(n=779) Estimate ($) P value

Any complication +27265 (22953-31576) <0.001

Weekend admission +11940 (4459-19421) 0.002

Hospital volume (5 unit increase) -1243 (-2921 to 435) 0.146

* Apart from cost of hospitalization data rest of the data is from 1998-2010.

† Variables included for the multivariable analysis included age (in 10 year increments),

gender, any procedural complications, use of intra-cardiac echocardiography (ICE), Deyo

modification of CCI, Weekend admission, primary payer, teaching hospital, hospital regions

(South, North-East, Mid-West, West), and Hospital volume in 5 unit increments.

‡ CCI denotes Charlson comorbidity index

§ Cost data were recorded beginning 2001 and hence we have information on hospitalization

cost from 2001 to 2010 only. For each year, cost was adjusted for inflation according to the

2010 value. (http://www.usinflationcalculator.com).

Balloon Mitral Valvuloplasty in the United States: A 13-Year Perspective

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