Changes in Left Ventricular Structure and Function following Renal Artery Revascularization

Abstract

Renovascular disease is associated with left ventricular hypertrophy (LVH) and left ventricular diastolic dysfunction, both of which are associated with increased mortality and cardiovascular events. However, the effects of renal artery revascularization on cardiac morphology and function are poorly understood and largely based upon retrospective studies. In order to characterize changes in ventricular function and morphology following renal artery revascularization, we identified a cohort of patients with baseline preoperative echocardiograms and studied them with repeat echocardiography at 6-12 months postrevascularization. Adult patients undergoing preoperative echocardiography and renal revascularization after March 2006 were identified from an operative registry and recruited to return for repeat echocardiography, blood pressure measurement, and collection of interval clinical and medication history 6-12 months following renal revascularization. Repeat echocardiograms were performed and interpreted according to American Society of Echocardiography recommendations for clinical trials of heart failure and other published guidelines. Systolic function was assessed as ejection fraction (EF), calculated using the modified Simpson's method. Diastolic function was categorized as normal, mild dysfunction, moderate dysfunction, or severe dysfunction based on published guidelines. Significance of longitudinal changes in continuous echocardiogram measures was assessed using paired t-tests, while longitudinal changes in categorical measures were assessed using McNemar's test. Twenty patients were recruited for postoperative echocardiography at a mean of 7.7 months following renal artery revascularization. Baseline systolic function was relatively preserved; mean EF was 61.3 + or - 8.5%, and only 2/20 patients (10%) had an EF <50%. Baseline diastolic dysfunction was identified in 15/20 patients (75%) and categorized as mild in one patient, moderate in 13, and severe in one. A significant mean decrease in left ventricular mass index (p = 0.018) was observed at follow-up. No significant change in EF was detected. Categorical groupwise change in diastolic dysfunction (normal/mild versus moderate/severe) was nonsignificant (p = 0.25), with two patients progressing from normal/mild to moderate/severe during follow-up and the remainder categorically unchanged. Interval decreases in left ventricular mass were observed following renal artery revascularization, while diastolic function was largely unchanged. Regression of LVH has been associated with reduced mortality and cardiovascular morbidity, and further investigation is required to understand the long-term effects of renal revascularization on survival and ventricular function. Assessment of cardiac function in the setting of symptomatic renal artery stenosis should include evaluation for diastolic dysfunction, which may represent the predominant form of target organ damage in patients with this diagnosis.