Graham S. Hillis

Left Atrial Volume A Powerful Predictor of Survival After Acute Myocardial Infarction

Background—After acute myocardial infarction (AMI), diastolic function assessed by Doppler echocardiography provides important prognostic information that is incremental to systolic function. However, Doppler variables are affected by multiple factors and may change rapidly. In contrast, left atrial (LA) volume is less influenced by acute changes and reflects subacute or chronic diastolic function. This may be of importance when one assesses risk in patients with AMI. Methods and Results—Three hundred fourteen patients with AMI who had a transthoracic echocardiogram with assessment of left ventricular (LV) systolic and diastolic function and measurement of LA volume during admission were identified. The LA volume was corrected for body surface area, and the population was divided according to LA volume index of 32 mL/m2 (2 SDs above normal). LA volume index was >32 mL/m2 in 142 (45%). The primary study end point was all-cause mortality. During follow-up of 15 (range 0 to 33) months, 46 patients (15%) died. LA volume index was a powerful predictor of mortality and remained an independent predictor (hazard ratio 1.05 per 1-mL/m2 change, 95% CI 1.03 to 1.06, P <0.001) after adjustment for clinical factors, LV systolic function, and Doppler-derived parameters of diastolic function. Conclusions—Increased LA volume index is a powerful predictor of mortality after AMI and provides prognostic information incremental to clinical data and conventional measures of LV systolic and diastolic function.

Outcome of Patients With Low Ejection Fraction Undergoing Coronary Artery Bypass Grafting Renal Function and Mortality After 3.8 Years

Background— There are few data regarding medium-term outcome of coronary artery bypass grafting (CABG) in patients with severe left ventricular (LV) systolic dysfunction, particularly in the modern era, and even less assessing preoperative factors that might identify patients at highest risk. Methods and Results— Three hundred seventy-nine consecutive patients with LV ejection fraction ≤35%, who underwent isolated first CABG between 1995 and 1999 were studied. Potential preoperative and perioperative predictors of outcome were recorded and patients followed-up for a median of 3.8 years. The primary study end-point was all-cause mortality. The 30-day, 1-year, and 3-year survival rates were 94.5%, 88%, and 81%, respectively. The independent predictors of mortality were preoperative estimated glomerular filtration rate (hazard ratio [HR], 0.98; 95% confidence interval [CI], 0.97 to 0.99 per mL/min/1.73m2; P<0.001) and age (HR, 1.03; 95% CI, 1.01 to 1.06 per year; P=0.005). Conclusions— Patients with significant LV systolic dysfunction undergoing isolated CABG using contemporary techniques have a good medium-term survival. Renal dysfunction is the strongest independent predictor of mortality.

Contrast Echocardiography Using Intravenous Octafluoropropane and Real-time Perfusion Imaging Predicts Functional Recovery After Acute Myocardial Infarction

Akinesia after acute myocardial infarction (MI) may be reversible, secondary to stunning, or irreversible, as a result of extensive myocyte necrosis. Distinguishing these 2 entities soon after MI is difficult, but has important clinical implications. The current study assessed the use of intravenous myocardial contrast echocardiography (MCE) in this setting. A total of 35 patients were studied 2 (+/- 1) days after an acute MI. Of these, 31 (91%) underwent myocardial revascularization. Perfusion was assessed using real-time MCE and an intravenous infusion of octafluoropropane microbubbles. Repeated echocardiograms were obtained 56 (+/- 29) days later. Normal perfusion predicted functional recovery with a positive predictive value of 66% and a negative predictive value of 81%. The accuracy of the technique was superior in myocardial segments supplied by the left anterior descending coronary artery (positive and negative predictive value: 70% and 90%, respectively). In multivariable analysis, the mean MCE perfusion score in akinetic segments was the most powerful independent predictor of functional recovery (odds ratio 8.6, P =.02). These data suggest that real-time intravenous MCE is a useful predictor of functional recovery of akinetic myocardium after acute MI.