Dobutamine stress echocardiography for the detection of significant coronary artery disease in renal transplant candidates.

Prophylactic coronary revascularization may reduce the risk for cardiac events in diabetic renal transplant candidates. No published data exist on the accuracy of dobutamine stress echocardiography (DSE) for the diagnosis of angiographically defined coronary artery disease (CAD) in renal transplant candidates. The purpose of this study is to examine the accuracy of DSE for the detection of CAD in high-risk renal transplant candidates compared with coronary angiography. Fifty renal transplant candidates with diabetic nephropathy (39 patients) or end-stage renal disease (ESRD) from other causes (11 patients) underwent prospectively performed DSE, followed by quantitative coronary angiography (QCA) and qualitative visual assessment of CAD severity. Twenty of 50 DSE tests were positive for inducible ischemia. Twenty-seven patients (54%) had a stenosis of 50% or greater by QCA, 12 patients (24%) had a stenosis of greater than 70% by QCA, and 16 patients (32%) had a stenosis greater than 75% by visual estimation. The sensitivity and specificity of DSE for CAD diagnosis were respectively 52% and 74% compared with QCA stenosis of 50% or greater, 75% and 71% compared with QCA stenosis greater than 70%, and 75% and 76% for stenosis greater than 75% by visual estimate. On long-term follow-up (22.5 +/- 10.1 months), 6 of 30 patients (20%) with negative DSE results and 11 of 20 patients (55%) with positive DSE results had a cardiac death, myocardial infarction (MI), or coronary revascularization. Six of 27 patients (22%) with a QCA stenosis of 50% or greater had a cardiac death or MI compared with none of the 23 patients (0%) with QCA stenosis less than 50% (P = 0.025). We conclude that DSE is a useful but imperfect screening test for angiographically defined CAD in renal transplant candidates.

The prevalence of cardiac valvular insufficiency assessed by transthoracic echocardiography in obese patients treated with appetite-suppressant drugs.

BACKGROUND: After case reports of cardiac-valve abnormalities related to the use of appetite suppressants were published, we undertook a study to determine the prevalence of the problem using transthoracic echocardiography. METHODS: We examined patients who had taken dexfenfluramine alone, dexfenfluramine and phentermine, or fenfluramine and phentermine for various periods. We enrolled obese patients who had taken or were taking these agents during open-label trials from January 1994 through August 1997. We also recruited subjects who had not taken appetite suppressants and who were matched to the patients for sex, height, and pretreatment age and body-mass index. The presence of cardiac-valve abnormalities, defined by the Food and Drug Administration and Centers for Disease Control and Prevention as at least mild aortic-valve or moderate mitral-valve insufficiency, was determined independently by at least two cardiologists. Multivariate logistic-regression analysis was used to identify factors associated with cardiac-valve abnormalities. RESULTS: Echocardiograms were available for 257 patients and 239 control subjects. The association between the use of any appetite suppressant and cardiac-valve abnormalities was analyzed in a final matched group of 233 pairs of patients and controls. A total of 1.3 percent of the controls (3 of 233) and 22.7 percent of the patients (53 of 233) met the case definition for cardiac-valve abnormalities (odds ratio, 22.6; 95 percent confidence interval, 7.1 to 114.2; P<0.001). The odds ratio for such cardiac-valve abnormalities was 12.7 (95 percent confidence interval, 2.9 to 56.4) with the use of dexfenfluramine alone, 24.5 (5.9 to 102.2) with the use of dexfenfluramine and phentermine, and 26.3 (7.9 to 87.1) with the use of fenfluramine and phentermine. CONCLUSIONS: Obese patients who took fenfluramine and phentermine, dexfenfluramine alone, or dexfenfluramine and phentermine had a significantly higher prevalence of cardiac valvular insufficiency than a matched group of control subjects.

Echocardiography in the evaluation of cardiac sources of emboli: the role of transthoracic echocardiography.

Cardioembolism is responsible for a significant number of systemic emboli including approximately 15% of all ischemic strokes. Transthoracic echocardiography has contributed to the understanding of cardioembolism and has been used to detect specific and potential cardiac sources of systemic emboli and risk stratify patients with specific clinical findings for subsequent cardiovascular events. Findings from transthoracic echocardiography indicate that stasis is an important prerequisite for intracardiac thrombosis while reversal of stasis and thrombolysis appear operative in embolism of existing thrombus. Transthoracic echocardiography allows a sensitive and specific noninvasive means to detect left ventricular thrombus, valvular vegetation, and intracardiac tumor, lesions that are directly responsible for cardioembolism. Transthoracic echocardiography can also detect lesions that could potentially contribute to cardioembolism but are not specific causes. Examples of these potential lesions include mitral valve prolapse, patent foramen ovale, and interatrial septal aneurysm. Finally, population-based studies and prospective clinical trials have indicated that the results of transthoracic echocardiography have predictive value for subsequent cardiovascular events and hence provide a means for stratification of patients at risk for cardioembolism. The latter is most notable for the group of patients with nonvalvular atrial fibrillation where left ventricular dysfunction and increased left atrial size are independent predictors for subsequent stroke.

Frequent occurrence of occult pulmonary embolism from venous sheaths during endomyocardial biopsy.

To determine the frequency of occult right heart thromboembolism during endomyocardial biopsy, 51 cardiac transplant recipients undergoing routine endomyocardial biopsy were studied echocardiographically. Patients were randomized to two groups. In Group 1, the venous sheath was flushed between each biopsy attempt; in Group 2, it was flushed only at the time of initial placement. Right heart thromboemboli were identified in 18 (35%) of 51 patients. Seventeen (94%) of these 18 patients were in Group 2. Patients requiring more than six biopsy attempts had a significantly higher incidence of embolism. Other variables such as antiplatelet therapy, operator experience and total time of the procedure did not correlate with occurrence of thrombus. All right heart emboli were asymptomatic. These data demonstrate a high incidence of occult pulmonary embolism during uncomplicated routine endomyocardial biopsy. Meticulous flushing of the introducer sheath significantly reduces the incidence of thrombus formation in intravenous sheaths.