Evaluation of left main coronary artery stenosis by transthoracic echocardiography.

OBJECTIVE: We sought to demonstrate left main coronary artery (LM) stenosis by transthoracic echocardiography. BACKGROUND: Evaluation of LM stenosis was done mostly by transesophageal echocardiography in patients with coronary artery disease. METHODS: A total of 1456 patients with coronary artery disease were studied, of which 801 patients (55%) had adequate coronary flow assessment. The LM and the adjacent segments of left anterior descending coronary artery and left circumflex coronary artery were evaluated by color flow and Doppler. Mosaic flow and/or peak diastolic velocity of greater than or equal to 1.5 m/s was considered abnormal. These findings were correlated with stenoses at coronary angiography. A total of 40 patients who had abnormal diastolic flow in LM by transthoracic echocardiography constituted group 1 and 56 patients with normal LM flow constituted the control group (group 2). RESULTS: The peak diastolic velocities in LM in group 1 ranged between 1.5 and 4.4 m/s (mean 2.11 +/- 0.78 m/s). Of the 40 patients in group 1, 34 had significant LM stenosis by coronary angiography (sensitivity of 85%, positive predictive value 82.5%). The velocities in LM in group 2 ranged between 0.4 and 1.2 m/s (mean 0.66 +/- 0.25 m/s). In all, 49 of 56 patients in this group had normal LM on coronary angiography (88% specificity, negative predictive value 90.7%). The remaining 7 had distal LM stenosis. Mosaic flow in LM indicated significant LM stenosis in 85% of patients, whereas normal flow in LM did not rule out distal LM stenosis in 12% of patients. CONCLUSIONS: LM stenosis could be assessed by transthoracic echocardiography with an acceptable degree of sensitivity and specificity.

Coronary artery bypass grafting with or without cardiopulmonary bypass in patients with preoperative non-dialysis dependent renal insufficiency: a randomized study.

OBJECTIVE: Preoperative renal insufficiency is a predictor of acute renal failure in patients undergoing coronary artery revascularization with cardiopulmonary bypass. Off-pump coronary artery bypass grafting has been shown to be less deleterious than on-pump bypass in patients with normal renal function, but the effect of this technique in patients with non-dialysis dependent renal insufficiency in a randomized study is unknown. METHODS: From August 2004 through October 2005, 116 consecutive patients with preoperative non-dialysis-dependent renal insufficiency (glomerular filtration rate measured using the Modification of Diet in Renal Disease equation [MDRD GFR] < or = 60 mL x min(-1) x 1.73 m(-2)) undergoing primary coronary artery bypass grafting were randomized to on-pump (n = 60) and off-pump (n = 56) groups. MDRD GFR and serum creatinine levels were measured preoperatively and postoperatively at days 1 and 5. The changes in renal function and clinical outcomes were compared between the two groups. RESULTS: Preoperative characteristics were comparable between the two groups. The repeated-measures analysis of variance was performed on the data that showed worsening of renal function in the on-pump group compared with the off-pump group (serum creatinine, P < .000; glomerular filtration rate, P < .000). Further analysis of subgroups of patients with diabetes alone, hypertension alone, and combined hypertension and diabetes also showed significant deterioration renal function in the on-pump group compared with the off-pump group. In covariate analysis, diabetes has emerged as a significant covariate by serum creatinine criteria while compromised left ventricular function has emerged as a significant covariate by glomerular filtration rate criteria. These analyses showed that the use of cardiopulmonary bypass is significantly associated with adverse renal outcome (P < .000). Three patents required hemodialysis in the on-pump group and none in the off-pump group. The mean number of grafts per patient was 3.85 +/- 0.86 and 3.11 +/- 0.89 in the on-pump and off-pump groups, respectively (P < .001), but the indices of completeness of revascularization, 1.00 +/- 0.08 for off-pump coronary bypass and 1.01 +/- 0.08 for on-pump coronary bypass, were similar (P = .60). CONCLUSIONS: This study suggests that on-pump as compared with off-pump coronary artery bypass grafting is more deleterious to renal function in diabetic patients with non-dialysis dependent renal insufficiency. MDRD GFR is a more sensitive investigation than serum creatinine levels to assess renal insufficiency in patients undergoing coronary bypass.

Demonstration of recanalized left coronary artery after thrombolysis by transthoracic echocardiography.

BACKGROUND: Demonstration of recanalized coronary artery is mostly done by angiographic techniques. Early bedside demonstration of reperfusion after thrombolysis by transthoracic echocardiography (TTE) has important implications in the subsequent risk stratification and timing of coronary interventions. METHODS: In this study, 12 patients with acute anterior myocardial infarction who received thrombolytic therapy were studied. Echocardiographic Doppler evaluation of left main coronary artery, proximal left anterior descending coronary artery (LAD), and proximal left circumflex coronary artery were studied before, during, and after thrombolytic therapy. Coronary flow in these arterial segments was assessed both by color flow and velocity measurements. These results were compared with coronary angiographic studies performed within 30 minutes to 48 hours of thrombolysis. RESULTS: Blood flow in left main coronary artery, LAD, and left circumflex coronary artery could be assessed in 9 patients. There was no demonstrable flow in LAD in 6 patients before thrombolysis. In 7 patients flow could be demonstrated in LAD after thrombolysis within 15 minutes to 6 hours. The peak flow velocity in LAD at a localized area of turbulence postthrombolysis varied from 1.8 to 4.5 m/s. One patient showed mosaic color flow in left main coronary artery with a peak velocity of 1.9 m/s before thrombolysis that improved to a laminar flow with a peak velocity of 1.0 m/s after thrombolysis. Two patients showed normal flow in proximal LAD, but no flow in mid-LAD. Two patients did not show any flow in LAD even after 12 hours of thrombolysis. There was good correlation of site of critical narrowing in LAD by TTE with coronary angiography in 6 patients. In 3 patients absent flow in mid-LAD by TTE correlated with total occlusion of either proximal (one patient) or mid-LAD (two patients). CONCLUSIONS: Demonstration of recanalized infarct-related left coronary artery soon after thrombolytic therapy is feasible. Locating the actual site of critical narrowing at bedside by TTE has important implications in the subsequent treatment of patients with acute anterior wall myocardial infarction.