1

Prevalence of Renal Artery Stenosis in Hypertensive

Patients Undergoing Diagnostic Coronary Angiography

Jawad M.Hawas ,Amanj Abu Bakir Khaznadar ,Israa Khaleel M Ali

,Kawyan Hussien Karim

Abstract

Background: Atherosclerotic renal artery stenosis (RAS) is an important

cause of secondary hypertension as well as ischemic nephropathy.

Objective: To determine the prevalence of RAS and its related risk

factors in hypertensive patients whose undergoing coronary

angiography.

Patients and method: A total of 122 hypertensive patients underwent

coronary and renal angiography at the same time, from a period of

1/1/2012 to 30/6/2012 . 57 patients were males and 65 were females,

with mean age 58.6 ± 9.5 years. The risk factors analyzed for any

association with RAS.

Results: 23 patients were found to have significant RAS (≥ 50% luminal

diameter).of those 15 patients was above the age of 60 and 8 patients

below the age of 60 with a significant p-value (0.027).there was

significant association between RAS and systolic hypertension and serum

creatinin level. There was no significant association between RAS and

gender ,smoking ,DM ,hyperlipidemia and obesity.

Conclusions: There was significant RAS in significant numbers of

patients with CAD, elderly patients ,systolic hypertension and patients

with impaired renal function.

Key words: RAS ,hypertension, coronary angiography.

Introduction

Renal artery stenosis (RAS) is defined as narrowing of the renal artery

lumen. The most common cause of RAS is atherosclerosis, usually

involves the main renal artery and the perirenal aorta [1].

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Prevalence of RAS in general population is unknown; some studies have

demonstrated that coronary artery disease (CAD) is one of the most

important causes of death in patients with atherosclerotic RAS. In

addition, a high prevalence of RAS has been reported in patients with

documented CAD [2, 3].

Renal angiography is a standard method for the detection of RAS that is

readily performed in combination with coronary angiography [4]. RAS is

one of the most common causes of secondary hypertension [5, 6].

Atherosclerosis is the most common cause, especially in older patients;

the characteristic lesion is an ostial stenosis. Irregular narrowing affects

the distal renal artery, sometimes extending into intrarenal branches [7].

Both hypertension and chronic renal failure secondary to RAS are

potentially reversible disorders [8, 9, 10, 11].

There is no present study of prevalence of RAS has been performed in

unselected populations [12]. Thus, many studies for its diagnosis have

carried out in patients with documented vascular diseases elsewhere in

the body like CAD and peripheral vascular disease [13, 14,15,16,17].

Atherosclerotic RAS is an important and frequently unrecognized

contributor to refractory hypertension, ischemic nephropathy, and cardiac

destabilization syndrome (unstable angina, flash pulmonary edema, and

decompensated heart failure) [18-19]. It is a progressive disease leading

to renal atrophy over time and chronic kidney disease despite control of

hypertension [20-21]. Presence and severity of incidental RAS is an

independent predictor of mortality in atherosclerotic patients regardless of

the mode of treatment of underlying coronary artery disease [22].

Hypertension is a condition in which arterial blood pressure is chronically

elevated [23]. For an individual patient, hypertension should be

diagnosed when most readings are at a level known to be associated with

significantly higher cardiovascular risk without treatment [24].

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In the United State of America 28.7% of the adult individual have

hypertension, which defined as any one of the following: systolic blood

pressure ≥140mmHg; diastolic blood pressure ≥90; taking

antihypertensive. [25]

During the last years, hypertension treatment has led to significant

dropping of cardiovascular mortality and delayed progression of renal

disease development [26].

Table-1: Definition of hypertension. [23]

Category Systolic BP Diastolic BP

BP

Optimal <120 <80

Normal <130 85

High normal 130-139 85-89

Hypertension

Grade1(mild) 140-159 90-99

Grade2(moderate) 160-179 100-109

Grade 3 (severe) ≥180 ≥110

Isolated systolic hypertension

Grade 1 140-159 <90

Grade 2 ≥160 <90

A study of hypertensive patients undergoing coronary angiography for

presumptive RAS in the United States found the prevalence of significant

RAS (stenosis more than 50%) to be 19.2% [27]. The prevalence of

significant RAS to be 13% in Japanese hypertensive patients[28].

Patients and methods

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The study is a randomized prospective study conducted on hypertensive

patients whose undergoing diagnostic coronary angiography.

A total of 122 patients were enrolled in this study in catheterization

laboratory at sulaimani center for heart disease from period of 1st of

January till 30th of June 2012. So that informed consents were taken. All

angiographic procedures done by flat detector Catheterization laboratory

machine.

A detailed history is taken from them and full physical examinations are

done including general examination, vital sign. Their weight, height and

body mass index is calculated by the following equation:

BMI=weight/(height)2. Obesity is defined as BMI>30kg/m

2.

Blood is taken from the patients and sent for laboratory investigation

including (total serum cholesterol, serum triglyceride level, low density

lipoprotein level (LDL), high density lipoprotein level (HDL), FBS,

blood urea and serum creatinine.

The procedures were done under local anesthesia for all the cases of

coronary angiography and renal angiography were done through femoral

artery approach between anterior superior iliac spine and symphysis

pubis. At first, we did coronary angiography for the left circulation of the

heart to look for the type of coronary disease, if it is present or not and

the number of vessels involved, then coronary angiography for the right

circulation was done and by using the same catheter for the right side

angiography the renal angiography was performed. Sometime we faced

problem to canulate renal artery, therefore we used pigtail catheter to

visualize the right and left renal artery at the same time.

We regard ≥ 50% narrowing of the lumen of the artery as significant and

the narrowing that calculate less than this measurement as non significant

and if no any narrowing found, the patient regarded as normal renal artery

angiogram. As shown in (Figure 3, 4 and 5)

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Figure 3: Normal bilateral renal artery angiogram

Figure 4: Significant proximal right RAS

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Figure 5: Significant ostial left RAS

Inclusion criteria:

Hypertensive patients with suspected ischemic heart disease attending

catheterization laboratory for diagnostic angiography.

Exclusion criteria:

1- Hypertension from other secondary causes.

2- Previous diagnosis of RAS.

3- Patients with history of renal artery angioplasty.

4- Emergency coronary angiography.

Statistical analysis

Data collected, tabulated and analyzed using computer program SPSS.

Chi-square test used to calculate P-value. Significant data regarded when

P-value is ≤ 0.05.

Results

A total of 122 consecutive hypertensive patients (57 males and 65

females) have been enrolled in this study with a mean age of 58.6±9.5

7

years underwent coronary and renal angiography. There is one (0.8%)

patient in the age group below 40 years, 23 (18.9%) patients between

40-49 years, 41 (33.6%) patients between 50-59 years, 42 (34.4%)

patients between 60-69 years, 12(9.8%) patients between70-79 years and

3 (2.5%) patients above 80 years. (Table 2)

Table-2: Groups of patients according to their age

Age interval (years) Number Percentage

<40 1 0.8%

40-49 23 18.9%

50-59 41 33.6%

60-69 42 34.4%

70-79 12 9.8%

80+ 3 2.5%

Total 122 100%

Family history of hypertension is found in 27 (22.1%) patients while it is

negative in 95 (77.9%) patients.

Thirty eight (31.1%) patients are smoker, 84 (68.9%) patients are not, 39

(32%) patients have Diabetes Mellitus, and 83 (68%) patients are not, 45

(36.9%) patients have hyperlipidemia and 77 (63.1%) are not. (Table 3)

Table3: Risk factors for atherosclerosis (122patients)

Risk factors Positive Negative

Family history of hypertension 27 (22.1%) 95 (77.9%)

Smoking 38 (31.1%) 84 (68.9%)

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Diabetes mellitus 39 (32%) 83 (68%)

Hyperlipidemia 45 (36.9%) 77 (63.1%)

CAD is found in 94 (77.1%) patients, and 28 (22.9%) patients have

normal coronary artery. Of those with CAD, 45 (36.9%) patients have

one vessel disease (1 VD), 31 (25.4%) patients have two vessels disease

(2 VD) and 18 (14.8%) patients have three vessels disease (3VD).

Figure 1: Coronary artery disease among the patients (VD=Vessel

disease)

Among all the patients, significant RAS is found in 23 patients

representing (18.9%) with stenosis ≥ 50% while non significant RAS

found in 22 patients representing (18.0 %) and 77 patients representing (

63.1%) have normal RA angiogram. Figure 2 shows RAS among the

patients.

28 (22.9%)

45 (36.9%)

31 (25.4%)

18 (14.8%)

0

5

10

15

20

25

30

35

40

45

50

Normal 1 VD 2 VD 3 VD

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Figure 2: RAS distribution among the patients

Out Of the total number, of 23 (18.9%) patients with significant RAS, 15

( 12.3 %) patients are in the age group≥60 and 8 ( 6.6%) patients in the

age group< 60, p-value=0.027. There were 8 (6.6%) males and 15

(12.3%) females have significant RAS , p-value=0.15. Seven (5.7%)

patients have BMI ≥ 30 and 16 (13.1%) patients have BMI < 30 with p-

value=0.4. while 17 (13.9%) patients are not, p-value=0.3

Mean ± SD of SBP was 155±22 of the patients with significant RAS with

p-value=0.02, while mean ±SD of DBP was 90±10.5 with p-value=0.5.

Table 4 shows RAS in relation to hypertension.

Table 4: RAS in relation to hypertension

Variables RAS≥50% NoRAS P-value

Systolic Blood Pressure 155±22 144±21 0.02

Diastolic Blood Pressure 90±10.5 88±14 0.5

77 (63.1%)

22 (18%) 23 (18.9%)

0

10

20

30

40

50

60

70

80

90

Normal Non-significant RAS Significant RAS

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Angiographic finding reveal that 21(17.2 %) patients with significant

RAS have CAD and 2 (1.6 %) patients have no CAD, p-value=0.034.

According to the vessels involved, 9(7.4 %) patients have one vessel

disease, 7(5.7%) patients have two vessels disease and 5 (4.1%) patients

have three vessels with p-value=0.23. (Table5)

Table 5: RAS in relation to CAD

Variables RAS≥ 50 No RAS p-value

CAD

Yes 21 (17.2%) 73 (59.9%)

0.034

No 2 (1.6%) 26 (21.3%)

Discussion

We evaluated the prevalence of RAS and its related risk factors in

hypertensive patients who are undergoing diagnostic coronary

angiography. RAS has been associated with hypertension and chronic

renal failure, both conditions are potentially reversible. However,

identifying RAS may be difficult as there are no definite clues for

suspecting it and the investigations used are comparatively invasive and

expensive. For that reason, in our study, the diagnosis of RAS is made for

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hypertensive patients who are already undergoing diagnostic coronary

angiography, rather than for diagnosis of RAS per se.

Atherosclerotic RAS is one aspect of systemic atherosclerotic disease.

This concept is supported by the observations that atherosclerotic RAS is

identified approximately in 12% of the subjects undergoing coronary

angiography [29, 30], and 26% of the subjects investigated for PAD[32].

ARAS is a cause of both hypertension and renal insufficiency; the latter

coupled with increased risk of progression to end stage renal disease [32].

As a result, ARAS is the underlying disease in 10-20% of the patients

entering dialysis program [33].

In our study, 15(12.3%) patients with significant RAS was in the age

group ≥60 and 8(6.6%) patients in the age group<60, p-value=0.027,

which is statistically significant, and this compatible with the studies

done by Saleh AA et al 2004 in Jordan [34]. Massoni M et al.2006, Iran

[35]. Dzielinska Z et al.2007, Poland [29].and Vahedparast H et al. 2011,

Iran [36]. The present study is in contrast to the study conducted by Shah

SS et al.2010 Peshawar [37]. Which was attributed to the low percentage

of elderly patients in that study

Regarding the gender, there are female predominance, although the p-

value =0.15 which is non significant and this is compatible with studies

done by Saleh AA et al 2004 in Jordan[34] Cohen MG et al. 2005

Argentina [30] and, Vahedparast H et al. 2011, Iran[36]. And to lesser

extend with studies done by Massoni M et al.2006,Iran[35] and Shah SS

et al. 2010 Peshawar[37], in that they show significant correlation with

female gender.

Association between CAD and RAS reveal p-value=0.034 which is

significant, but according to number of vessels involved , p-value=0.23

which is not significant this agrees with the study done by Shah SS, et al

.2010, Peshawar[37], and disagrees with study done by Cohen MG,et

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al.2005, Argentina[30], Dzielinska Z, et al,2007, Poland[29]and El-

Mawardy RH,et al.2008, Egypt[42] Vahedparast H,et al,2011, Iran[36].

This difference may be related to that in these studies, larger number of

patients are involved in comparison with our study.

In our study obesity has no significant relation with RAS, the p-value=0.4

and this result is similar to both studies done by Cozier Y, et al.2006,

USA,[38] and Vahedparast H et al.2011, Iran [36].

The severity of hypertension is not related significantly with RAS as

shown in study done by Shah SS e t al.2010, Peshawar [37]. But the SBP

related significantly with RAS, with p-value=0.02 which is similar to the

study done by Saleh AA et al.2004, Jordan.[34] And Dzielinska Z ,et

al.2007, Poland[29].There is no significant relation to family history

neither in our study nor other studies done by Saleh N, 2001, Iran [39]

and Hajsadeghi S, et al.2009, Iran [40]. Smoking is not related

significantly with RAS, and this agrees with studies done by Cohen

MG,et al.2005,Argentina[30], Masoomi M,et al.2006, Iran[35], Shah

SS,et al.2010, Peshawar [37], and Vahedparast H, et al.2011, Iran[36].

And it disagrees with study done by Saleh AA et al. 2004, Jordan [34].

The latter was not explainable. Serum creatinine were directly related

with RAS, and this agree with most of the studies done by Saleh AA ,et

al. 2004,Jordan[34],Dzielinska Z, et al.2007, Poland[29] and Sani SH, et

al ,2008, Iran[30]. While serum lipid was not significantly related with

RAS.The same result is confirmed by both studies Saleh AA, et al.2004,

Jordan[34] and Cohen MG,et al.2005, Argentina[30].

In our study, abnormal renal artery angiogram is found significantly more

often in elderly patients with high SBP and high serum creatinine levels,

but smoking, obesity, D.M. gender, family history, hyperlipidemia have

no significant relation with RAS. Therefore, risk factors for the

development of atheromatous changes may be different from

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conventional CAD risk factors, and detecting them is very important

because RAS is one of the causes of hypertension and renal failure.

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