Prognostic significance of renal function in patients undergoing dobutamine stress echocardiography
Background. Dobutamine stress echocardiography (DSE) is used for risk stratification of patients with suspected coronary artery disease (CAD). However, the prognostic value of DSE among the entire strata of renal function has yet to be determined. We assessed the prognostic value of renal function relative to DSE findings. Methods. We studied 2292 patients, divided into 729 (32%) patients with normal renal function [creatinine clearance (CrCl) >90 ml/min] and 1563 (68%) with renal dysfunction, classified as mild (CrCl: 60-90 ml/min) in 933, moderate (CrCl: 30-60 ml/min) in 502 and severe (CrCl < 30ml/min) in 128 patients. All patients underwent DSE for the evaluation of known or suspected CAD and were followed for a mean of 8 years. Results. New wall motion abnormalities during DSE and mildly, moderately and severely abnormal CrCl were powerful independent predictors for all-cause mortality, cardiac death and hard cardiac events (cardiac death and non-fatal myocardial infarction). Kaplan-Meier curves demonstrated that patients with normal DSE and renal dysfunction have greater probability for cardiac death and hard cardiac events compared to those with normal renal function. The warranty of a normal DSE in the presence of moderate renal dysfunction was 15 and 36 months for 10 and 20% risk for cardiac death and hard cardiac events, respectively. Conclusions. The presence and severity of renal dysfunction has additional independent prognostic value over DSE findings. The low-risk warrantee period after a normal DSE is determined by the severity of renal dysfunction.