Prevalence of Renal Artery Disease and Its Prognostic Significance in Patients Undergoing Coronary Bypass Grafting Victor Aboyans, MD, PhDa,b,*, Benedicte Tanguy, MDa, Ileana Desormais, MD, MPHb,c, Vincent Bonnet, MDa, Michel Chonchol, MD, MPHd, Marc Laskar, MDc, Dania Mohty, MD, PhDa,b, and Philippe Lacroix, MDb,c Several studies demonstrated the prognostic importance of renal failure and peripheral artery disease in patients undergoing coronary artery bypass grafting (CABG), but data regarding the prognostic value of renal artery disease in this context are scarce. We aimed to study the prevalence and prognostic value of renal artery disease in patients undergoing CABG. We assessed by duplex ultrasound the renal arteries of 429 consecutive patients who underwent CABG, of whom 401 had satisfactory imaging quality to detect >60% renal artery stenosis (RAS) and/or an elevated resistive index (ERI >0.80). Of the 401 subjects included (age 68 – 10 years, 83% men), 40 (10%) had RAS and 35 (9%) had ERI. Nine patients (2.2%) had both conditions. Patients were followed up for 12.4 – 7.0 months. The primary outcome was composite, including 30-day death, stroke, and/or myocardial infarction. In a multivariate model adjusted for age, gender, cardiovascular (CV) risk factors, renal function, chronic obstructive pulmonary disease, the use of off-pump CABG, CV co-morbidities, and drugs, the presence of ERI was strongly associated with the occurrence of the composite outcome (odds ratio 4.3, 95% confidence interval 1.7 to 9.9, p [ 0.0006). Similarly, ERI, not RAS, was significantly associated with the 30-day acute kidney disease and the midterm mortality, as well as fatal and nonfatal CV events. In conclusion, regardless of renal function and other factors, the renal resistive index is a strong predictor of CV and renal events after CABG. Renal duplex ultrasound can identify a subgroup of patients at high risk of CABG. Ó 2014 Elsevier Inc. All rights reserved. (Am J Cardiol 2014;114:1029e1034)

Atherosclerosis often affects multiple vascular beds concomitantly. The increased prevalence of renal artery stenosis (RAS) in association with coronary artery disease (CAD) or peripheral artery disease (PAD) is well documented.1e3 In patients with CAD, RAS may be screened by renal angiography concomitant to coronary angiography, but this technique is now supplanted by noninvasive methods, including ultrasound and magnetic resonance imaging. In patients with CAD, duplex ultrasound has been advocated as the first-line imaging method of renal arteries.4 Although several studies have demonstrated the prognostic interest of renal failure and PAD in patients undergoing coronary artery bypass grafting (CABG) surgery,5,6 data on the consequences of RAS during CABG are scarce. Also, the postoperative degradation of kidney function is a matter of concern, and the

Departments of aCardiology and cThoracic & Cardiovascular Surgery and Angiology, Dupuytren University Hospital, Limoges, France; bInserm U1094, School of Medicine, University of Limoges, Limoges, France; and d Division of Renal Diseases and Hypertension, University of Colorado, Denver, Colorado. Manuscript received April 5, 2014; revised manuscript received and accepted July 2, 2014. Funding: None. See page 1033 for disclosure information. *Corresponding author: Tel: (þ33) 555 058 953; fax: (þ33) 555 056 384. E-mail address: [email protected] (V. Aboyans). 0002-9149/14/$ - see front matter Ó 2014 Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.amjcard.2014.07.011

risk factors for this complication are not yet well established. The aim of this study was to investigate the prevalence of RAS and elevated renal resistive index in patients with CAD undergoing CABG and its relation with outcomes. We hypothesized that the prevalence of these conditions in patients undergoing CABG is high and could be associated with poorer cardiovascular (CV) and renal outcomes.

Methods We prospectively included 429 consecutive patients undergoing elective isolated CABG, except those on renal dialysis or with a history of renal transplantation. Secondarily, patients with poor duplex imaging quality were also excluded. Clinical data were investigated preoperatively. Chronic kidney disease (CKD) was defined as an estimated glomerular filtration rate 180 cm/s, renorenal (peak systolic velocity) ratio >2.7, and/or renal-to-aortic peak systolic velocity ratio >3.5. The renal index was determined at the renal hilum, using the following equation: Renal index ¼ (peak systolic velocity  end-diastolic velocity)/peak systolic velocity. An elevated resistive index (ERI) was defined by a renal resistance index >0.80. The primary outcome was composite, including the occurrence of any of the following events within the first 30 postoperative days, whichever first: death, stroke, or perioperative myocardial infarction (defined by new Q waves in at least 2 contiguous leads on the postoperative electrocardiogram and/or troponin peak and creatine phosphokinase peak >10 times the ninety-ninth percentile).12 A secondary postoperative outcome was defined by the occurrence of acute kidney injury, according to the risk of renal dysfunction; injury to the kidney; failure of kidney function, loss of kidney function and end-stage kidney disease injury-risk “R” criteria (serum creatinine increase of 1.5 times or 25% decrease of glomerular filtration rate compared with baseline data).13 Two other midterm secondary outcomes have been determined: the occurrence of death and a composite outcome (death, stroke or acute coronary syndrome, or myocardial revascularization) during the follow-up period. Data are reported as mean (SD) and number (percentage) for continuous and categorical variables, respectively.

RAS 10,0% ERI RAS Normal

Normal 81,3% Figure 1. Distribution of renal duplex findings.

Categorical and continuous variables were analyzed using Fisher’s exact test and the Student t test, respectively. The Kaplan-Meier survival method was used for the comparison of survival according to the presence of RAS or ERI, using the log-rank test. Multivariate analysis was performed using a logistic regression model for the 30-day events and Cox proportional hazards model for the midterm events. For this purpose, several models were run by adding sequentially baseline demographic factors, CKD, CV risk factors, comorbidities, CV treatment, and preoperative data. Because some patients could have both conditions (RAS and ERI), these 2 variables have been assessed concomitantly in a same model, rather than taking into account the 3 patient groups. A p value

Prevalence of renal artery disease and its prognostic significance in patients undergoing coronary bypass grafting.

Several studies demonstrated the prognostic importance of renal failure and peripheral artery disease in patients undergoing coronary artery bypass gr...
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