Abstract
This study explored the prevalence and predictors of renal artery stenosis in a cohort of 525 hypertensive patients referred for elective coronary procedures. Patients underwent coronary and renal arteriography. The study defined renal artery stenosis as ≥60% luminal obstruction (physiologic or hemodynamic significance was not tested). Patients were classified into groups of those with normal renal arteries, those with insignificant renal artery stenosis, and individuals with significant renal artery stenosis. The mean age was 52.6±8.5 years, and 403 (76.8%) were males. Significant renal artery stenosis was found in 3.6%. It correlated significantly with hypertension duration (P=.005), history of cerebrovascular stroke (P=.01), history of angioplasty to >1 coronary vessel (P=.003), and 3‐vessel coronary disease (P=.0003). Multivariate regression analysis identified 2‐vessel and 3‐vessel coronary artery disease as independent predictors of renal artery stenosis, with odds ratios of 4.9 and 12.1, respectively. It was concluded that invasive screening for renal artery stenosis was probably warranted only in hypertensive patients with multivessel coronary disease referred for elective coronary procedures.
Atherosclerosis is the most common cause of obstructive renal artery disease, accounting for 90% of cases of renal artery stenosis (RAS). 1 Hemodynamically significant RAS is a well‐recognized cause of systemic arterial hypertension, renal insufficiency, or both. 2 Moreover, RAS has deleterious effects on the prognosis of cardiovascular disease. It has been observed that the prognosis in patients with coronary artery disease (CAD) and RAS is poor, with a 4‐year survival rate as low as 62%. 3 On the other hand, it is reported that the prognosis in patients with cardiovascular disease and RAS can be improved by interventional treatment of RAS. 3 , 4 In one series in patients with congestive heart failure and RAS, 90% had no further episodes of decompensation after renal artery stenting. 3 Owing to the progressive nature of RAS in the absence of adequate treatment, early detection and treatment of RAS could be important to decrease the incidence of dialysis in some patients. 5
The prevalence of RAS rises with increasing age and with the presence of atherosclerosis of the aorta and carotid, coronary, and peripheral arteries. 2 Age older than 65 years, the presence of multiple risk factors (especially a history of smoking), multivessel CAD, a history of peripheral vascular or carotid disease, severe hypertension, and unexplained renal dysfunction or decreased creatinine clearance all have been previously reported as major predictors of renal artery disease. 6 , 7 , 8 , 9 , 10 , 11 , 12 In this study, we sought to define its prevalence and explore some potential predictors of angiographic RAS in a cohort of hypertensive patients referred for elective coronary procedures.
Methodology
Population
We included 525 consecutive hypertensive patients admitted to catheterization laboratories for elective diagnostic or interventional coronary procedures during the period from November 2000 to June 2002. The presence of hypertension was defined as a systolic blood pressure ≥140 mm Hg and/or diastolic blood pressure ≥90 mm Hg, previously recorded by repeated noninvasive office measurements, and recommendations for lifestyle modifications or antihypertensive drug therapy. Other causes of secondary hypertension—other than RAS—were excluded by appropriate clinical and laboratory testing. The study also excluded patients with acute coronary syndrome; those with a serum creatinine level >2.0 mg/dL; and patients with a single kidney, a history of nephrectomy, or a unilateral nonfunctioning kidney. Before inclusion, informed consent was obtained from each patient and the study protocol was reviewed and approved by our local institutional human research committee, as it conforms to the ethical guidelines of the 1975 Declaration of Helsinki.
Methods
All patients underwent selective left and right coronary arteriography using the standard technique. Selective renal arteriography was performed using a Judkins right catheter inserted consecutively in the ostium of both renal arteries in the left anterior oblique projection with 10‐ to 20‐degree angulation. A dose of 5 to 10 mL of iso‐osmolar iodine‐containing contrast medium (iodixanol) was injected into each renal artery. When the ostia of the renal arteries did not appear clearly, the angulation was modified to obtain better visualization. The presence of an accessory renal artery was suspected when a portion of the kidney was not opacified in the late phase of angiography; descending aortography was then performed using a pigtail catheter with its head positioned just above the renal artery level. Angiographic data were individually reviewed by an experienced cardiologist blinded to the clinical data, and the degree of stenosis was evaluated by visual estimation. Patients were considered to have significant RAS if they had at least a 60% luminal obstruction of one or both of the main renal arteries (including accessory renal arteries) or one of their major branches. Significant coronary stenosis was defined as ≥70% luminal obstruction of at least one sizable coronary artery (measuring ≥2.5 mm in diameter), seen in 2 different projections, or at least 50% luminal obstruction of the left main coronary artery (LMCA). Patients with significant stenosis of the LMCA were considered to have 2‐vessel disease, and those with significant stenosis of the LMCA and right coronary artery were considered to have 3‐vessel disease. According to the presence and severity of RAS, we classified the population into patients with normal renal arteries (group 1), those with insignificant RAS (group 2), and those with significant RAS (group 3).
Statistical Analysis
All continuous variables were presented as mean ± SD if they were normally distributed. Differences in the normally distributed variables were assessed using the t‐test and the paired t‐test for dependent variables. Categorical variables were described with absolute and relative (percentage) frequencies. Pearson chi‐square test and one‐way ANOVA tests were used to compare the distribution of categorical and continuous variables, respectively, among the 3 study groups. A probability value of P<.05 was considered statistically significant. Multivariate logistic regression analysis was performed to identify independent predictors of the presence of RAS. Analyses were performed with SPSS version 12.0 statistical package (SPSS Inc., Chicago, IL).
Results
Patient Characteristics
A total of 525 hypertensive patients were enrolled in the current study, which comprised 482 (91.8%) patients with normal renal arteries (group 1), 24 (4.6%) with insignificant RAS (group 2), and 19 (3.6%) with significant RAS (group 3). Table I shows the baseline characteristics of the entire study cohort as well as of the 3 study groups. The mean age of the cohort was 52.6±8.5 years; 403 participants (76.8%) were male. Among the study population, 272 (51.8%) were smokers, 197 (37.5%) were diabetic, and 47 (9.0%) had a family history of ischemic heart disease. The duration of known hypertension was 7.5±5.8 years; systolic blood pressure was 154±26 mm Hg and diastolic blood pressure was 90±12 mm Hg.
Table I.
Baseline Characteristics of the Entire Cohort and the 3 Study Groups
| Total Cohort (n = 525) | Group 1 (n = 482) | Group 2 (n = 24) | Group 3 (n = 19) | P Value | |
|---|---|---|---|---|---|
| Age, y | 52.6±8.5 | 52.5±8.3 | 53.8±10.7 | 53.8±11.6 | >.05 |
| Male | 403 (77) | 386 (76) | 21 (88) | 13 (95) | >.05 |
| Smoking | 272 (52) | 246 (51) | 16 (67) | 10 (53) | >.05 |
| Diabetes | 197 (38) | 178 (37) | 12 (50) | 7 (37) | >.05 |
| Family history of IHD | 47 (9) | 42 (9) | 1 (4) | 4 (21) | >.05 |
| Duration of hypertension, y | 7.5±5.8 | 7.4±5.5 | 7±5.8 | 11.7±9.9 | <.01 |
| Systolic BP, mm Hg | 154±26 | 153±26 | 153±19 | 159±24 | >.05 |
| Diastolic BP, mm Hg | 90±12 | 90±12 | 89±11 | 91±14 | >.05 |
| Prior CVS | 10 (2) | 7 (1.5) | 1 (4.2) | 2 (10.5) | <.05 |
| Prior MI | 127 (24) | 114 (24) | 7 (29) | 6 (32) | >.05 |
| Prior PCI in 1 vessel | 57 (11) | 52 (11) | 4 (17) | 1 (5) | >.05 |
| Prior PCI in >1 vessel | 13 (2.5) | 10 (2) | 0 (0) | 3 (16) | <.01 |
| Prior CABG | 12 (2) | 12 (2.5) | 0 (0) | 0 (0) | >.05 |
| IVS thickness, mm | 11.5±2.1 | 11.5±2.1 | 11±1.8 | 12.6±2.7 | .07 |
| LV PW thickness, mm | 11.7±2.2 | 11.7±2.2 | 11.3±1.9 | 12.1±2.4 | >.05 |
| M mode LV EF, % | 60±8 | 60±9 | 60±10 | 61±7 | >.05 |
| Serum creatinine, mg/dL | 1.0±0.34 | 1.0±0.34 | 1.1±0.35 | 1.0±0.34 | >.05 |
| Fasting serum glucose, mg/dL | 110±34 | 110±34 | 104±29 | 119±38 | >.05 |
| PP serum glucose, mg/dL | 164±48 | 164±48 | 158±38 | 176±57 | >.05 |
Abbreviations: BP, blood pressure; CABG, coronary artery bypass grafting; CVS, cerebrovascular stroke; EF, ejection fraction; IHD, ischemic heart disease; IVS, interventricular septum; LV, left ventricular; MI, myocardial infarction; PCI, percutaneous coronary intervention; PP, postprandial; PW, posterior wall. Continuous variables are presented as mean ± SD, while categorical variables are presented as No. (%).
Comparison of baseline characteristics among the study groups revealed that the duration of known hypertension was longer in group 3 (significant RAS) compared with groups 2 and 1 (insignificant stenosis and normal renal arteries, respectively); differences were significant (11.7±9.9 vs 7±5.8 and 7.4±5.5 years, respectively; P=.005). Similarly, a history of both cerebrovascular stroke and prior angioplasty in >1 coronary artery was statistically more frequent in group 3 than in groups 2 and 1 (2 [10.5%] vs 1 [4.2%] and 7 [1.5%]; P=.01 and 3 [15.8%] compared with 0 [0%] and 10 [2.1%]; P=.003, respectively]. Interventricular septal thickness tended to be higher in group 3 in comparison with groups 2 and 1 (12.6±2.7 vs 11±1.8 and 11.5±21 mm, respectively); this trend did not reach statistical significance (P=.07). Otherwise, all other clinical, echocardiographic, and laboratory findings were statistically similar among the 3 study groups (Table I).
Coronary angiographic characteristics in the study population as well as in the 3 study groups are shown in Table II. The prevalence of 3‐vessel CAD increased progressively in a stepwise fashion with increasing severity of RAS, being observed in 56 (11.6%), 5 (20.8%), and 7 (36.8%) among groups 1, 2 and 3, respectively (P=.0003).
Table II.
Coronary Angiographic Characteristics of the Entire Cohort and the 3 Study Groups
| Total Cohort (n = 525) | Group 1 (n = 482) | Group 2 (n = 24) | Group 3 (n = 19) | P Value | |
|---|---|---|---|---|---|
| Normal coronary arteries | 136 (25.9) | 131 (27.2) | 3 (12.5) | 2 (10.5) | >.05 |
| Insignificant CAD | 73 (13.9) | 69 (14.3) | 1 (4.2) | 3 (15.8) | >.05 |
| Single‐vessel disease | 118 (22.5) | 114 (23.7) | 2 (8.3) | 2 (10.5) | >.05 |
| 2‐Vessel disease | 78 (14.9) | 17 (14.7) | 5 (20.8) | 2 (10.5) | >.05 |
| 3‐Vessel disease | 68 (13) | 56 (11.6) | 5 (20.8) | 7 (36.8) | <.001 |
| >3‐Vessel disease | 31 (5.9) | 22 (4.6) | 6 (25) | 3 (15.8) | >.05 |
| LMCA disease | 6 (1.1) | 5 (1) | 1 (4.2) | 0 (0) | >.05 |
| Ectatic coronary arteries | 13 (2.5) | 12 (2.5) | 1 (4.2) | 0 (0) | >.05 |
Abbreviations: CAD, coronary artery disease; LMCA, left main coronary artery. All variables are presented as No. (%).
Multivariate logistic regression analysis identified 2‐vessel and 3‐vessel CAD as independent predictors of RAS, with odds ratios of 4.9 and 12.1, respectively (Table III).
Table III.
Multivariate Logistic Regression Model Demonstrating the Influence of Different Variables on the Presence of Renal Artery Stenosis
| β Coefficient | Odds Ratio (95% CI) | P Value | |
|---|---|---|---|
| Sex | 0.4 | 1.5 (0.3–4.0) | .46 |
| Smoking | −0.02 | 0.98 (0.1–3.5) | .96 |
| Diabetes | −0.08 | 0.91 (0.2–5.0) | .82 |
| Family history of IHD | −0.2 | 0.82 (0.3–5.0) | .74 |
| Prior CVS | 1.4 | 0.25 (0.01–2.90) | .16 |
| Prior MI | 0.25 | 1.3 (0.2–3.6) | .6 |
| Prior PCI in >1 vessel | 0.06 | 1.1 (0.01–3.00) | .9 |
| Normal | 0.4 | 1.5 (0.4–6.0) | .96 |
| coronary arteries | |||
| Insignificant CAD | 1.1 | 3.0 (0.7–9.0) | .88 |
| Single‐vessel CAD | 0.7 | 2.0 (0.6–4.0) | .92 |
| 2‐Vessel CAD | 1.6 | 4.9 (0.5–12.3) | <.05 |
| 3‐Vessel CAD | 2.5 | 12.1 (0.6–22.0) | <.001 |
| LMCA disease | −4.5 | 0.01 (−0.01 to 2.00) | .87 |
| Ectatic | 1.6 | 0.8 (0.02–3.00) | .83 |
| coronary arteries | |||
Abbreviations: CAD, coronary artery disease; CI, confidence interval; CVS, cerebrovascular stroke; IHD, ischemic heart disease; LMCA, left main coronary artery; MI, myocardial infarction; PCI, percutaneous coronary intervention.
Discussion
Hypertension is closely associated with atherosclerotic RAS, both as a predisposing risk factor and a possible clinical manifestation of the disease. 13 In view of the progressive nature of RAS (in one report, progression of renal artery atherosclerosis occurred in 44% of cases, with the incidence of progression to complete occlusion being 16% over 10 years of follow‐up) 14 , 15 , 16 , 17 , 18 , 19 and its potential to worsen the prognosis of cardiovascular disease, 3 , 20 , 21 early detection and timely treatment of the condition are important to prevent progression to total occlusion 18 and to preserve renal function. 22 Noninvasive diagnostic tools such as duplex ultrasonography, computed tomography, and magnetic resonance imaging have unsolved technical limitations concerning the assessment of the renal arteries. Duplex ultrasonography of the renal arteries, in addition to providing functional information on the stenosis, does not involve the use of ionizing radiations or contrast media and may be sensitive and specific for detection of RAS in the hands of an experienced operator. However, it is highly operator‐dependent, and direct visualization of the renal arteries might not always be feasible. Therefore, angiography of the renal arteries performed at the time of coronary artery angiography is emerging as an invasive diagnostic tool to optimize the detection of RAS in hypertensive patients who are more likely to have RAS and who are undergoing coronary procedures. 23
The results indicated that 3.6% of this cohort have significant RAS. Recently published studies have reported a prevalence that ranges from 9.7 to 17%. 10 , 24 , 25 , 26 , 27 , 28 However, in these studies significant RAS was defined as ≥50% luminal occlusion, while the current study considered lesions in the renal artery significant when they were ≥60%. The younger age of this cohort might also have contributed to the lower prevalence observed. Another possible explanation for the lower prevalence of RAS in this group of patients is that we performed selective right and left renal angiography with a Judkins right coronary diagnostic catheter. Selective cannulation of the ostium of the renal artery might have missed or underestimated discrete ostial lesions that would otherwise be apparent on abdominal aortography using a pigtail catheter clear of the ostium. Moreover, for safety purposes, we excluded patients with creatinine levels >2.0 mg/dL and patients with a single kidney (including those with unilateral nonfunctioning kidney). Two previous studies reported that the creatinine level was an independent predictor of RAS by multiple logistic regression analysis, 24 , 25 and one reported that low glomerular filtration rate independently predicted RAS. 10 Some patients excluded because of high creatinine levels who were not enrolled in this study might well have had RAS.
The duration of hypertension was significantly longer in patients with significant RAS as compared with those with normal or insignificantly stenosed renal arteries. The same group of patients showed a trend to have thicker interventricular septa compared with the other 2 groups but without statistical significance. Previously, Hess and colleagues 29 observed that asymmetrical septal hypertrophy appeared to be dependent on the duration and severity of hypertension. Moreover, Zhang and associates 24 reported that 10 years’ duration of hypertension was an independent predictor of atherosclerotic RAS by multiple regression analysis. In the patients studied, it is likely that longer‐standing essential hypertension might have been closely involved in the development of RAS, which might in turn perpetuate and sustain the hypertensive process if the stenoses were physiologically important (It is not known whether all lesions >60% are of clinical significance). In such a case, renal artery stenting would hardly achieve blood pressure control without medications. A meta‐analysis of 3 small randomized studies comparing medical therapy with balloon angioplasty reported significant improvement in both systolic and diastolic blood pressure readings, 30 but no study to date has reported complete cure of hypertension that obviates the need for medications. Moreover, similar improvements might have been achieved by modification of antihypertensive medication regimens.
Both the presence of multivessel coronary disease and a history of prior cerebrovascular stroke were strongly correlated with significant RAS. Numerous studies have reported that RAS is independently predicted by significant multivessel coronary stenosis 10 , 24 , 25 , 26 , 27 , 28 , 31 , 32 and by atherosclerotic peripheral or carotid disease. 25 , 28 , 31 , 32 This emphasizes the diffuse, widespread nature of atherosclerosis that often simultaneously involves many arterial trees.
Some physicians might be reluctant to perform invasive renal angiography to avoid the hazards of excess radiation and be concerned about the effect of extra contrast media in patients undergoing coronary angiography, but with the use of a small amount of iso‐osmolar contrast medium (iodixanol) in patients with a serum creatinine <2 mg/dL, the additional risk of developing contrast‐induced kidney injury is probably negligible. 33
Conclusions
RAS is not uncommon among selected hypertensive patients referred for elective diagnostic or interventional coronary procedures for known or suspected CAD. Screening for RAS by invasive renal arteriography might be warranted at the time of catheterization in hypertensive patients with multivessel coronary disease, but not in those with single‐vessel coronary disease or those with normal coronary arteries.
Acknowledgments
Acknowledgments: The authors express their deep gratitude to all the staff members of the cardiology department in Ain Shams University Hospitals who have sincerely and rigorously supported the performance of this work.
References
- 1. Rammer M, Kramar R, Eber B. Atherosclerotic renal artery stenosis. Dtsch Med Wochenschr. 2007;132(46):2458–2462. [DOI] [PubMed] [Google Scholar]
- 2. Voiculescu A, Grabensee B, Jung G, et al. Renovascular disease: a review of diagnostic and therapeutic procedures. Minerva Urol Nefrol. 2006;58(3):127–149. [PubMed] [Google Scholar]
- 3. Stack R. Renal artery stenosis‐under‐diagnosed and undertreated in the cardiac patient? J Invasive Cardiol. 1999;11:103–106. [PubMed] [Google Scholar]
- 4. Gross CM, Krämer J, Waigand J, et al. Ostial renal artery stent placement for atherosclerotic renal artery stenosis in patients with coronary artery disease. Cathet Cardiovasc Diagn. 1998;45:1–8. [DOI] [PubMed] [Google Scholar]
- 5. Rimmer JM, Gennari FJ. Atherosclerotic renovascular disease and progressive renal failure. Ann Intern Med. 1993;118:712–719. [DOI] [PubMed] [Google Scholar]
- 6. White CJ, Ramee SR, Collins TJ, et al. Global revascularization: the role of the cardiologist. Int J Cardiovasc Intervent. 2000;3:71–79. [DOI] [PubMed] [Google Scholar]
- 7. Rigatelli G, Rigatelli G. Routine screening angiography of extra‐cardiac arteries during cardiac catheterization: angiographer’s delirium or common sense. Am J Med. 2004;117:443–444. [DOI] [PubMed] [Google Scholar]
- 8. Buller CE, Nogareda JG, Ramanathan K, et al. The profile of cardiac patients with renal artery stenosis. J Am Coll Cardiol. 2004;43:1606–1613. [DOI] [PubMed] [Google Scholar]
- 9. Rigatelli G. Aotoiliac angiography during coronary artery angiography detects significant occult aortoiliac and renal atherosclerosis in patients with coronary atherosclerosis. Int J Cardiovasc Imaging. 2004;20:299–303. [DOI] [PubMed] [Google Scholar]
- 10. Weber‐Mzell D, Kotanko P, Schumacher M, et al. Coronary anatomy predicts presence or absence of renal artery stenosis. A prospective study in patients undergoing cardiac catheterization for suspected coronary artery disease. Eur Heart J. 2002;23:1684–1691. [DOI] [PubMed] [Google Scholar]
- 11. Harding MB, Smith LR, Himmelstein SI, et al. Renal artery stenosis: prevalence and associated risk factors in patients undergoing routine cardiac catheterization. J Am Soc Nephrol. 1992;2:1608–1616. [DOI] [PubMed] [Google Scholar]
- 12. Thomas CS, Varghese K, Habib F, et al. Extent and severity of atherosclerotic vascular disease in patients undergoing coronary angiography–the Kuwait Vascular Study. Angiology. 2003;54(1):85–92. [DOI] [PubMed] [Google Scholar]
- 13. Takehiro Y, Fumihiro I, Naoki I, et al. Prevalence and predictors of renal artery stenosis in patients undergoing cardiac catheterization. Hypertens Res. 2002;25:553–557. [DOI] [PubMed] [Google Scholar]
- 14. Conlon PJ, Little MA, Pieper K, et al. Severity of renal vascular disease predicts mortality in patients undergoing coronary angiography. Kidney Int. 2001;60:1490–1497. [DOI] [PubMed] [Google Scholar]
- 15. Greco BA, Breyer JA. The natural history of renal artery stenosis: who should be evaluated for suspected ischemic nephropathy? Semin Nephrol. 1996;16:2–11. [PubMed] [Google Scholar]
- 16. Schreiber MJ, Pohl MA, Novick AC. The natural history of atherosclerotic and fibrous renal artery disease. Urol Clin North Am. 1984;11:383–392. [PubMed] [Google Scholar]
- 17. Wollenweber J, Sheps SG, Davis GD. Clinical course of atherosclerotic renovascular disease. Am J Cardiol. 1968;21:60–71. [DOI] [PubMed] [Google Scholar]
- 18. Zierler RE, Bergelin RO, Isaacson JA, et al. Natural history of atherosclerotic renal artery stenosis: a prospective study with duplex ultrasonography. J Vasc Surg. 1994;19(2):250–258. [DOI] [PubMed] [Google Scholar]
- 19. Dean RH, Kieffer RW, Smith BM, et al. Renovascular hypertension: anatomic and renal function changes during drug therapy. Arch Surg. 1981;116:1408–1415. [DOI] [PubMed] [Google Scholar]
- 20. MacDowall P, Kalra PA, O’Donoghue DJ, et al. Risk of morbidity from renovascular disease in elderly patients with congestive heart failure. Lancet. 1998;352:13–16. [DOI] [PubMed] [Google Scholar]
- 21. Valentine RJ, Clagett GP, Miller GL, et al. The coronary risk of unsuspected renal artery stenosis. J Vasc Surg. 1993;18:433–440. [PubMed] [Google Scholar]
- 22. Harden PN, MacLeod MJ, Rodger RSC, et al. Effect of renal‐artery stenting on progression of renovascular renal failure. Lancet. 1997;349:1133–1136. [DOI] [PubMed] [Google Scholar]
- 23. Rigatelli G, Rigatelli G. Assessing the appropriateness and increasing the yield of renal angiography in patients undergoing coronary angiography: a scoring system. Int J Cardiovasc Imaging. 2006;22:135–139. [DOI] [PubMed] [Google Scholar]
- 24. Zhang Y, Ge JB, Qian JY, et al. Prevalence and risk factors of atherosclerotic renal artery stenosis in 1,200 chinese patients undergoing coronary angiography. Nephron Clin Pract. 2006;104(4):c185–c192. [DOI] [PubMed] [Google Scholar]
- 25. Dzielińska Z, Januszewicz A, Demkow M, et al. Cardiovascular risk factors in hypertensive patients with coronary artery disease and coexisting renal artery stenosis. J Hypertens. 2007;25(3):663–670. [DOI] [PubMed] [Google Scholar]
- 26. Wang Y, Ho DS, Chen WH, et al. Prevalence and predictors of renal artery stenosis in Chinese patients with coronary artery disease. Intern Med J. 2003;33(7):280–285. [DOI] [PubMed] [Google Scholar]
- 27. Rigatelli G, Rigatelli G. Predictors of renal artery stenosis in patients with normal renal function undergoing coronary angiography. Minerva Cardioangiol. 2006;54(1):145–149. [PubMed] [Google Scholar]
- 28. Yang J, Hu D, Liu K, et al. High incidence of renal artery stenosis in patients undergoing coronary angiography. Zhonghua Nei Ke Za Zhi. 2002;41(1):24–27. [PubMed] [Google Scholar]
- 29. Hess OM, Börlin HJ, Jenni R, et al. Asymmetric septal hypertrophy in patients with arterial hypertension. Schweiz Med Wochenschr. 1983;113(49):1854–1856. [PubMed] [Google Scholar]
- 30. Nordmann AJ, Woo K, Parkes R, et al. Balloon angioplasty or medical therapy for atherosclerotic renal artery stenosis? A meta‐analysis of randomized controlled trials Am J Med. 2003;114:44–50. [DOI] [PubMed] [Google Scholar]
- 31. Cohen MG, Pascua JA, Garcia‐Ben M, et al. A simple prediction rule for significant renal artery stenosis in patients undergoing cardiac catheterization. Am Heart J. 2005;150(6):1204–1211. [DOI] [PubMed] [Google Scholar]
- 32. Przewlocki T, Kablak‐Ziembicka A, Tracz W, et al. Prevalence and prediction of renal artery stenosis in patients with coronary and supraaortic artery atherosclerotic disease. Nephrol Dial Transplant. 2008;23(2):580–585. [DOI] [PubMed] [Google Scholar]
- 33. Jo S, Youn TJ, Koo BW, et al. Renal toxicity evaluation and comparison between Visipaque (Iodixanol) and Hexabrix (Ioxaglate) in patients with renal insufficiency undergoing coronary angiography: the RECOVER study: a randomized controlled trial. J Am Coll Cardiol. 2006;48:924–930. [DOI] [PubMed] [Google Scholar]