2005;129:138-145 J Thorac Cardiovasc SurgDonelli, Jan Baan and Ottavio Alfieri

Jan J. Schreuder, Alessandro Castiglioni, Francesco Maisano, Paul Steendijk, Andrea contractile state and energy efficiency after left ventricular restoration

Acute decrease of left ventricular mechanical dyssynchrony and improvement of

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Surgery for Acquired Cardiovascular Disease Schreuder et al

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Acute decrease of left ventricular mechanicaldyssynchrony and improvement of contractile state andenergy efficiency after left ventricular restorationJan J. Schreuder, MD, PhDa

Alessandro Castiglioni, MDa

Francesco Maisano, MDa

Paul Steendijk, PhDb

Andrea Donelli, MSa

Jan Baan, PhDb

Ottavio Alfieri, MDa

From the Department of Cardiac Surgery,a

San Raffaele University Hospital, Milan,Italy, and the Department of Cardiology,b

Leiden University Medical Center, Leiden,The Netherlands.

Received for publication July 4, 2003; re-visions received Feb 22, 2004; accepted forpublication March 30, 2004.

Address for reprints: Jan J. Schreuder, MD,PhD, Department of Cardiac Surgery, SanRaffaele University Hospital, Via Olgettina60,20132Milano, Italy (E-mail: schreuder@libero.it).

J Thorac Cardiovasc Surg 2005;129:138-45

0022-5223/$30.00

Copyright © 2005 by The American Asso-ciation for Thoracic Surgery

doi:10.1016/j.jtcvs.2004.03.057

138 The Journal of Thoracic and CardioDow

Objective: Surgical left ventricular restoration by means of endoventricular patchaneurysmectomy in patients with postinfarction aneurysm should result in acuteimproved left ventricular performance by decreasing mechanical dyssynchrony andincreasing energy efficiency.

Methods: Nine patients with left ventricular postinfarction aneurysm were studiedintraoperatively before and after ventricular restoration with a conductance volumecatheter to analyze pressure-volume relationships, energy efficiency, and mechan-ical dyssynchrony. The end-systolic elastance was used as a load-independent indexof contractile state. Left ventricular energy efficiency was calculated from strokework and total pressure-volume area. Segmental volume changes perpendicular tothe long axis were used to calculate mechanical dyssynchrony. Statistical analysiswas performed with the paired t test and least-squares linear regression.

Results: Endoventricular patch aneurysmectomy reduced end-diastolic volume by37% (P � .001), with unchanged stroke volume. Systolic function improved, asderived from increased �dP/dtmax, by 42% (P � .03), peak ejection rate by 28% (P� .02), and ejection fraction by 16% (P � .0002). Early diastolic function im-proved, as shown by reduction of �dP/dtmax by 34% (P � .006) and shortened � by30% (P � .001). Left ventricular end-systolic elastance increased from 1.2 � 0.6 to2.2 � 1 mm Hg/mL (P � .001). Left ventricular energy efficiency increased by 36%(P � .002). Left ventricular mechanical dyssynchrony decreased during systole by33% (P � .001) and during diastole by 20% (P � .005).

Conclusions: Left ventricular restoration induced acute improvements in contractilestate, energy efficiency, and relaxation, together with a decrease in left ventricularmechanical dyssynchrony.

Left ventricular (LV) postinfarction aneurysm is characterized byakinetic or dyskinetic LV wall motions, or both. Ventricular non-uniformity of contraction and relaxation reduces mechanical effi-ciency of ventricular filling and ejection and contributes to diastolicand systolic dysfunction.1,2 Consequently, postinfarction LV aneu-rysm is associated with reduced ejection fraction (EF) caused by LV

dilatation to maintain stroke volume (SV), with impaired LV relaxation and de-creased energy efficiency.

LV aneurysm resection according to a linear suture technique induced increased

LV ejection fraction (LVEF), but only slight hemodynamic improvements in pa-

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tients with congestive heart failure were observed.3-5 En-doventricular patch aneurysmectomy was introduced to im-prove LV geometry, showing better outcome comparedwith that seen with the linear suture technique.6-9 The effi-cacy and safety of a similar procedure was demonstrated ina multicenter study consisting of 439 patients with anteriormyocardial infarction.10

Reductions in regional LV wall-motion abnormalitiesafter patch aneurysmectomy have been demonstrated.11 Inprevious studies we observed that LV volume reduction bymeans of cardiomyoplasty or partial ventriculectomy inpatients with dilated cardiomyopathy decreased LV me-chanical dyssynchrony by decreasing LV wall stress.12,13

We hypothesized that LV volume decrease through theexcision of the akinetic area, the dyskinetic area, or both,and the geometric remodeling by means of LV restorationshould result in an acute decrease in mechanical dyssyn-chrony and, consequently, immediate improvement of LVenergy efficiency and performance. Therefore we analyzedthe intraoperative effects of LV restoration by means ofendoventricular patch aneurysmectomy on LV perfor-mance, on LV energy efficiency, and on mechanical dys-synchrony from the pressure-volume (P-V) plane by usingthe conductance catheter technique.12-18

MethodsStudy GroupNine consecutive patients with LV postinfarction aneurysm sched-uled to undergo endoventricular patch aneurysmectomy were stud-ied immediately before and after cardiopulmonary bypass (Table1). All patients had EFs of less than 35% and were in sinus rhythm.Seven patients concomitantly underwent coronary artery bypassgrafting (CABG). Patients were treated with prophylactic intra-aortic balloon counterpulsation from anesthetic induction until 24hours after the operation.

The study was approved by the medical ethics committee. Allpatients provided written informed consent.

InstrumentationAll patients received high-dose opioid anesthesia. A thermodilu-tion catheter was placed in the pulmonary artery. An intra-aorticballoon (8F, Narrowflex; Arrow International, Reading, Pa) wasintroduced through a femoral artery under transesophageal echo-cardiographic control. A combined micromanometer pressure-con-ductance catheter (7F, CD Leycom, Zoetermeer, The Netherlands)was inserted through a pulmonary vein into the left ventricle formeasurement of pressure and volume. The feasibility of the con-ductance catheter method during cardiac surgery has been shownin previous studies.13,15 Correct positioning of the conductancecatheter was verified by means of transesophageal echocardiogra-phy and by means of inspection of the segmental conductancesignals. The conductance catheter coupled to a cardiac functionanalyzer (Leycom CFL512, CD Leycom) measures LV segmental

and total volumes by using a dual-field excitation mode.12-16

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Time-varying segmental conductances reflect time-varying seg-mental LV volumes.17

The parallel conductance offset term was determined by meansof injection of 10 mL of hypertonic saline solution (6%) into thepulmonary artery.14 Effective conductance SV was defined as thedifference between conductance volumes at the times of �dP/dtmax and �dP/dtmax, which largely eliminates the contribution ofpossible regurgitant flows. Cardiac output was determined byperforming 4 thermodilution measurements at equidistant mo-ments in the ventilatory cycle.15 Absolute LV volumes were cal-culated by matching effective conductance SV with simulta-neously measured thermodilution SV and by subtracting parallelconductance from total conductance volume. Both the thermodi-lution and hypertonic saline methods are indicator dilution meth-ods and therefore independent of anticipated geometric changes, aswill be caused by means of endoventricular patch aneurysmec-tomy.

Surgical ProcedureThe surgical technique used was the endoventricular patch aneu-rysmectomy, as described by Dor and colleagues.7 After initiationof cardiopulmonary bypass with moderate hypothermia, the aortawas crossclamped, and cardiac arrest was obtained by infusion ofantegrade and retrograde cold blood cardioplegic solution. Coro-nary revascularization was performed first. Subsequently, a linearincision was made through the fibrotic area, and a part of theendocardial scar was resected. At the demarcation line betweennormal muscle and fibrous tissue, a Teflon double velour patch wasanchored inside the ventricle with a running polypropylene suture.The remnants of the aneurysmatic wall were sutured over the patchfor hemostasis.

Mechanical Ventricular DyssynchronyVentricular dyssynchrony assessment from segmental LV volumemeasurements has been previously described for cineangiographyand the conductance catheter.2,13,18 Time-varying segmental vol-ume, as measured with the conductance catheter, has been vali-dated by means of cineangiography.17 Mechanical ventricular dys-synchrony, as measured with the conductance catheter, has beenvalidated by means of tissue Doppler echocardiography.18 The

TABLE 1. Patient characteristicsPatientno. Age/sex

Associatedoperation NYHA EF (%)

1 61/M CABG II 322 70/F CABG II 353 64/M III 194 61/M CABG III 155 62/M III 156 73/M CABG III 257 66/F CABG III 228 65/M CABG II 339 57/M CABG III 16

NYHA, New York Heart Association; EF, ejection fraction; CABG, coronaryartery bypass grafting.

conductance catheter measures volume segments located perpen-

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dicular to the long heart axis. A volume segment was defined as

dyssynchronous when the volume change in that segment was inthe opposite direction (dyskinetic) or showed no change (akinetic)compared with total LV volume change. Segmental dyssynchronywas quantified by percentage time, and a segment was dyssyn-chronous in relationship to total volume change; total dyssyn-chrony was the average of segmental dyssynchrony in all seg-ments.2,13,18 Systolic dyssynchrony was calculated from R-waveto �dP/dtmax and diastolic dyssynchrony from �dP/dtmax to R-wave. The systolic phase was subdivided in early systole, fromR-wave to �dP/dtmax and late systole from �dP/dtmax to end-systolic volume (ESV). The diastolic phase was subdivided inearly diastole from ESV to peak filling rate and late diastole frompeak filling rate to R-wave.

Data Acquisition and AnalysisEchocardiography, LV pressure, and LV volume signals weredigitized at a sampling rate of 250 Hz and stored on hard disk forsubsequent analysis. In addition to volumetric variables, dyssyn-chrony, pressures, and the peak first derivatives, the followingvariables were calculated: �, the time constant of LV pressurerelaxation, which was defined as the time required from the LVpressure at peak �dP/dt to be reduced by half19, and peak ejectionrate, which was calculated as maximal �dV/dt. Effective LVEFwas calculated from the thermodilution-derived SV and LV end-diastolic volume (EDV), as measured with the conductance cath-eter. The load-independent indices of contractile state, end-systolicelastance (Ees), preload recruitable stroke work (PRSW), and therelationship of �dP/dtmax versus EDV were determined from P-Vloops acquired during preload reduction procedures. Stroke workdivided by total P-V area was used to determine the LV energy

Figure 1. LV P-V relationships during caval vein occluspatch aneurysmectomy. The P-V loops shifted to the lef

efficiency, according to the method of Suga and colleagues.20

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Measurement ProtocolHemodynamic measurements were obtained at two stages: imme-diately before and 15 minutes after cardiopulmonary bypass. Wecalibrated the conductance catheter at each stage of the procedureby determining parallel conductance and by means of thermodilu-tion SV. Steady state P-V loops were acquired for 15 secondsduring suspended ventilation. Preload reduction was performed bymeans of transient occlusion of the inferior vena cava during 15seconds to assess Ees, PRSW, �dP/dtmax-EDV, and LV energyefficiency during suspended ventilation. Data acquisitions beforeand after aneurysmectomy were performed with suspended intra-aortic balloon pump, but in patients with the lowest EF (patients 3,4, 5, and 9; Table 1), data acquisition was performed with anintra-aortic balloon pump at a 1:1 assist ratio.

StatisticsAll values are reported as means � SD. Differences betweenprebypass and postbypass hemodynamic data were assessed byusing paired t tests. Statistical relationships between variables weretested by using least-squares linear regression.

ResultsHemodynamicsCharacteristics of all patients are presented in Table 1.Identical doses (�5 �g · kg�1 · min�1) of dobutamine wereused before and after cardiopulmonary bypass in patientswith the lowest EF (patients 3, 4, 5, and 9).

Figure 1 shows typical P-V relationships of 2 patientsacquired during preload reduction before and after patchaneurysmectomy, indicating an increase in Ees in both

n 2 patients (A and B) before and after endoventricularr aneurysmectomy, with concomitant increases in Ees.

ion i

patients, with concomitant leftward shifts of the P-V loops.

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Table 2 provides data on all 9 patients measured before and

after patch aneurysmectomy. LV end-systolic pressure didnot change significantly, whereas LV end-diastolic pressureincreased by a mean of 4 mm Hg (P � .03). LVEDV andLVESV decreased by a mean of 37% (P � .001) and 51%(P � .0001), respectively. Cardiac index and heart rate (HR)increased by 34% (P � .01) and 30% (P � .01), respec-tively, whereas SV remained constant. The increase in HRcorrelated with a decrease in LVEDV (r � �0.679; P �.044).

Systolic function improved as indicated by a mean in-crease in �dP/dtmax of 42% (P � .03), peak ejection rateincreased by 28% (P � .02), and net EF increased by 16%(P � .0002). Early diastolic function improved as indicatedby a mean 34% decrease in �dP/dtmax (P � .006) and amean 30% decrease in � (P � .001). The contractile stateindices Ees and �dP/dtmax versus EDV and PRSW mark-edly improved, on average, by 83% (P � .001), 71% (P �.01), and 318% (P � .01), respectively. The LV energyefficiency, determined by stroke work divided by the P-Varea, improved by a mean relative increase of 36% (P �.002).

LV Mechanical DyssynchronyFigure 2 presents typical LV segmental and total volumerecordings during 4 consecutive heart cycles of 2 patientsbefore and after patch aneurysmectomy. Before aneurys-mectomy, the LV apical volume segments show the mostpronounced dyskinetic and akinetic characteristics. Obvious

TABLE 2. Hemodynamic data (n � 9)

B

HR (min�1) 7CI (L · min�1 · m�2) 1.9SV (mL) 4EDP (mm Hg) 9.ESP (mm Hg) 7EDV (mL/m2) 12ESV (mL/m2) 9�dP/dtmax (mm Hg/s) 78PER (mL/s) 45EF (%) 23.�dP/dtmax (mm Hg/s) �60� (ms) 5Ees (mm Hg/mL) 1.�dP/dtmax � EDV (mm Hg · s�1 · mL�1) 6.PRSW (mm Hg) 4SW/PVA (%) 38.

HR, Heart rate; CI, cardiac index; SV, stroke volume; EDP, end-diastolic prevolume; PER, peak ejection rate; EF, ejection fraction; Ees, end-systolicpressure-volume area.

decreases in apical segmental dyssynchrony are present

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after patch aneurysmectomy. Table 3 shows systolic anddiastolic dyssynchrony data of all patients measured beforeand after the procedure. Preoperatively, the 3 apical seg-mental volumes, representing dyskinetic and akinetic con-tributions of the postinfarction aneurysms (Figure 2), weresignificantly more dyssynchronous during systole and dias-tole compared with the basal segments (P � .001). Afteraneurysmectomy, LV total systolic dyssynchrony was de-creased relatively by a mean of 33% (P � .001), and totaldiastolic dyssynchrony was decreased relatively by a meanof 20% (P � .005), primarily because of decreases indyssynchrony of the 3 apical segments during systole anddiastole (Table 3). Postoperatively, the 2 apical segmentswere still significantly (P � .005) more dyssynchronouscompared with the 2 basal segments. Early systolic dyssyn-chrony, from R-wave to peak �dP/dtmax, did not changesignificantly, whereas late systolic dyssynchrony, from peak�dP/dtmax to LVESV, decreased relatively by a mean of54% (P � .0005, Table 4). Early LV diastolic dyssyn-chrony, from LVESV to peak filling rate, decreased rela-tively by a mean of 23% (P � .005), whereas late diastolicdyssynchrony, from peak filling rate to R-wave, did notchange significantly (Table 4).

Comparing preoperative and postoperative values re-vealed that systolic dyssynchrony correlated with Ees (P �.00066; Figure 3, A) and with � (P � .00006; Figure 3, B)and LV energy efficiency (P � .001; Figure 3, C). The netincrease in Ees after endoventricular patch aneurysmectomycorrelated significantly with a decrease in diastolic dyssyn-

Aneurysmectomy

After P value

6 99 � 21 �.01.5 2.62 � 0.5 �.012 48 � 12

13.8 � 3 �.033 79 � 185 78 � 18 �.0013 45 � 19 �.000176 1116 � 171 �.0341 578 � 190 �.02

39.4 � 13 �.000245 �803 � 72 �.006

41.3 � 9.2 �.001.6 2.2 � 1.0 �.001.5 22 � 14 �.012 72 � 22 �.016 52.5 � 16 �.002

; ESP, end-systolic pressure; EDV, end-diastolic volume; ESV, end-systolictance; PRSW, preload recruitable stroke work; SW, stroke work; PVA,

efore

6 � 16 � 06 � 14 � 34 � 13 � 32 � 37 � 22 � 16 � 81 � 19 � 72 � 09 � 42 � 26 � 1

ssureelas

chrony (P � .0094; Figure 3, D).

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DiscussionThis study shows significant acute beneficial effects of LVrestoration by means of endoventricular patch aneurysmec-

Figure 2. Tracings of LV volume segments during 4 conendoventricular patch aneurysmectomy. Dotted linesdyssynchrony and total LV dyssynchrony values alongare shown. LV restoration induced a marked decrease

TABLE 3. Left ventricular dyssynchrony I (n � 9)

Segments

Aneurysmectomy

Before After

Systole Diastole Systole Diastole

Apical 1 64 � 15 66 � 14 46 � 10* 51 � 8†Apical 2 46 � 9 49 � 15 27 � 11† 38 � 9*Mid 28 � 7 39 � 8 16 � 10‡ 26 � 14†Base 2 18 � 7 23 � 10 16 � 5 23 � 6Base 1 23 � 10 25 � 7 17 � 7 25 � 11Total 36 � 4 40 � 7 24 � 7‡ 32 � 6†

*P � .05.†P � .01.‡P � .001.

tomy in patients with LV postinfarction aneurysm. LV

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mechanical dyssynchrony was markedly reduced and LVenergy efficiency was markedly increased by the LV vol-ume reduction and surgical geometric remodeling. Theload-independent contractility indices Ees, PRSW, and�dP/dtmax-EDV acutely improved after LV restoration. The

tive heart beats of 2 patients (A and B) before and afterrt or end of the LV ejection phase. LV segmental

ong axis during systole (S%) and during diastole (D%)yssynchrony.

TABLE 4. Left ventricular dyssynchrony II (n � 9)Aneurysmectomy

P valueBefore After

Early systole 43 � 7 36 � 10 .08Late systole 28 � 7 13 � 8.5 .0004Early diastole 44 � 6 34 � 7 .004Late diastole 31 � 10.5 29 � 8 .66

Early systole, From R-wave to �dP/dtmax; late systole, from �dP/dtmax toend-systolic volume; early diastole, from end-systolic volume to peak fillingrate; late diastole, from peak filling rate to R wave.

secu, Stathe l

increase in Ees after patch LV restoration correlated in-

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versely with LV diastolic dyssynchrony. Early diastolicfunction, as shown by the LV relaxation indices �dP/dtmax

and �, improved.

HemodynamicsThe observed acute decrease in LVEDV by 37% and in-crease in EF from 24% to 39% on the average immediatelyafter endoventricular patch aneurysmectomy is consistentwith previous reported findings.11,21 The acute decreases inLVEDV and ESV after aneurysmectomy are also compara-ble with those observed acutely after partial ventriculec-tomy and long term after cardiomyoplasty.12,13

The LV relaxation indices �dP/dtmax and � are generallydecreased and prolonged, respectively, in congestive heartfailure and in LV aneurysm, which is indicative for LVmechanical dyssynchrony in early diastole.2,12,13,22 In thepresent patient group these variables also were markedlyabnormal, whereas � correlated strongly with systolic dys-synchrony (Figure 3, B). After patch aneurysmectomy,�dP/dtmax was lower and � was markedly shorter, indicat-ing an improvement in LV relaxation of the compromisedearly diastole.

Mean SV did not change significantly, whereas cardiacindex increased significantly because of the significant in-crease in HR. Heart increase, which correlated with thedecrease in LVEDV, was unlikely to be related to inotropicagents because they were administered in equal low dosagesbefore and after cardiopulmonary bypass in 4 patients.

End-diastolic compliance decreased immediately afterLV restoration. Previously, we demonstrated a considerableincrease in the slope of the diastolic P-V relationship aftercardiopulmonary bypass in patients undergoing CABG, in-dicating increases in passive ventricular stiffness.15 More-over, immediately after aneurysmectomy, LV end-diastolicpressure might have increased, possibly because of edemaaround suture lines.

LV Mechanical Dyssynchrony and Energy EfficiencyBefore endoventricular patch aneurysmectomy, marked LVdyssynchronic segmental volume changes were observedthroughout the cardiac cycle, indicating diastolic and sys-tolic dyskinetic and akinetic wall motion. They were con-verted into more synchronous wall-motion patterns afterpatch aneurysmectomy (Figure 2 and Tables 3 and 4).Nonuniformity of wall motion reduces the mechanical effi-ciency of ventricular ejection by inducing a premature onsetand impairment of LV relaxation.1,2 The aspect of segmen-tal volume dyssynchrony along the long heart axis, mostpronounced in the apical and midventricular zones, revealsthe ineffective mechanical cardiac work, which improvedtogether with the LV energy efficiency in all patients afterLV restoration. In all patients, 5 volume segments were

measured. However, in case of very large ventricles, the

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electrode distances of the basal segments were doubled toensure a maximal view of the left ventricle. Simultaneously,the relative contributions of those double segments weredoubled for total dyssynchrony calculations. Once the apexwas removed, the planes corresponded with the new apicalplanes, whereas the basal planes were still in the same

Figure 3. Regression diagrams showing Ees versus LV systolicdyssynchrony (SysDys, A); � versus LV systolic dyssynchrony (B);LV energy efficiency (EnerEffic; SW/PVA) versus LV systolic dys-synchrony (C); and changes in Ees versus changes in LV diastolicdyssynchrony (�DiaDys, D). Dotted lines represent 95% predic-tion limits.

position, although not always doubled. The calculated av-

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eraged dyssynchrony of the left ventricle therefore repre-sents a relative dyssynchrony index of the whole ventricle.

Although reduced, variable degrees of dyssynchrony re-mained present in the 2 apical segments after the aneurys-mectomy, indicating that the geometric reconstruction wasonly in part successful (Figure 2, B). Di Donato and col-leagues11 demonstrated improvements of regional wall mo-tion at the posterobasal, inferior, and anterobasal zones afterpatch aneurysmectomy. Wall stress decreases caused by LVvolume reduction have an LV synchronizing effect, as wasdemonstrated after partial left ventriculectomy and cardio-myoplasty.12,13 In the present study a similar reduction inwall stress occurs as LV volume is reduced, whereas sys-tolic pressure and wall thickness remain unaffected. Thesynchronizing effect of endoventricular patch aneurysmec-tomy can therefore be ascribed to excision of the akineticarea, the dyskinetic area, or both; surgical geometric remod-eling; and a decrease in wall stress caused by LV volumedecrease. LV mechanical dyssynchrony (mechanical ineffi-ciency) correlated markedly inversely with LV energy effi-ciency and with increase in Ees (Figure 3, C and D).

The conductance catheter technique allows an analysis ofdyskinesia and akinesia at high-time resolution, and as aconsequence, dyskinetic areas will be detected more fre-quently compared with techniques with lower temporalresolution, such as cine-angiography. Previous studies sug-gested that aneurysmectomy should be applied on dyski-netic but not akinetic areas. However, Di Donato and co-workers23 demonstrated that surgical outcome of LVrestoration is related to the extent of LV dyssynchrony andnot to dyskinesia or akinesia.

Contractile StateThe load-independent contractility indices Ees, PRSW, and�dP/dtmax versus EDV acutely improved after LV restora-tion. Similar findings were observed in an animal studyassessing acute effects of aneurysm plication.24 However,the study mentioned a decreased Frank-Starling relationship(SV vs sarcomere length), whereas this relationship wasimproved in a clinical endoventricular patch aneurysmec-tomy study.11 Both studies used LVEDV as a substitute forsarcomere length. But the decrease in LV dyssynchrony andthe LV volume reduction make an analysis in terms of theFrank-Starling relationship questionable because mean sar-comere length before and after aneurysmectomy are un-known. The Ees, however, is independent of the preloadreduction induced by the surgical LV reduction and there-fore suitable to apply in aneurysmectomy.

Limitations of the StudyAlthough 7 patients had additional CABG, some majoreffects, like the change in uniformity of contraction and

relaxation and the significant increase in Ees, can be pri-

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marily attributed to LV restoration because in a previousstudy we could not demonstrate a significant acute changein Ees after CABG.15 The number of patients in this studyis too small to perform a subgroup analysis (with or withoutCABG), and therefore the independent effects of CABG ondyssynchrony require further study.

The study was performed in patients after achievementof anesthesia, and some patients received small dosages ofdobutamine before and after aneurysmectomy. Moreover, inall patients intra-aortic balloon counterpulsation was ap-plied before and after the procedure. Therefore the absolutevalues of all measured variables might have been differentwhen measured in the awake state and without additionaltherapies.

The increased HR after CPB might have contributed toincreased Ees after LV restoration. However, Ees is rela-tively insensitive to changes in HR, as was demonstrated inanimal studies; only changes from very low HR to themidrange resulted in significant changes in Ees.25,26 HRinversely correlated with LV volume decrease, whereas nosignificant correlation between HR and Ees was observed.Moreover, equal dosages of inotropic agents were usedbefore and after LV restoration.

ConclusionsThe reduction in LV cavity volume after endoventricularpatch aneurysmectomy resulted in a significant immediateimprovement of the contractile state, as assessed by Ees,PRSW, and �dP/dtmax versus EDV.

LV mechanical dyssynchrony decreased, and LV energyefficiency increased significantly after LV restoration, prob-ably because of geometric improvements produced by thesurgical procedure and a decrease in LV volume, decreasingwall stress. Increase in Ees correlated significantly with adecrease in LV diastolic dyssynchrony. The applied con-ductance catheter technique allows intraoperative evalua-tion of the LV mechanical and energy efficiency, whichmight be of value for long-term outcome of LV restoration.

We thank Dr Hein Putter, PhD, for the statistical review.

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c and Cardiovascular Surgery ● Volume 129, Number 1 145 on June 5, 2013 rnals.org

2005;129:138-145 J Thorac Cardiovasc SurgDonelli, Jan Baan and Ottavio Alfieri

Jan J. Schreuder, Alessandro Castiglioni, Francesco Maisano, Paul Steendijk, Andrea contractile state and energy efficiency after left ventricular restoration

Acute decrease of left ventricular mechanical dyssynchrony and improvement of

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