Milrinone echocardiographic viability test: A pilot study

We assessed the utility of milrinone to predict recovery of function after surgical myocardial revascularization In patients with severe baseline left ventricular systolic dysfunction caused by coronary artery disease (CAD). Prediction of viable myocardial segments that will regain function after re vascularization may help in the selection of patients who will benefit from coronary artery bypass graft surgery (CABG) as well as aid in the choice o f target sites for coronary revascularization. We Investigated 20 consecuti ve patients with CAD and left ventricular ejection fraction less than or eq ual to 40% who had evidence of myocardial viability by either thallium scan or dobutamine viability test and were candidates for elective CABG. Left v entricular regional wall. motion and global ejection fraction were assessed by transesophageal echocardiography in the operating room. Measurements we re done before and 10 minutes after milrinone infusion, and Immediately aft er CABG. Left ventricular wall motion score was derived by means of a la-se gment model. Functional improvement for each segment was defined as a wall motion change >1. Baseline ejection fraction was 27% +/- 5% (mean rt SD). E jection fraction increased to 35% +/- 5% after milrinone infusion (P < .000 1) and to 36% +/- 6% after CABG (P < .0001). Post-CABG ejection fraction wa s significantly correlated with postmilrinone ejection fraction (r = 0.65, P <less than> .0001), Milrinone infusion resulted in augmentation of contra ction in 98 of the 209 abnormal segments (wall motion score greater than or equal to2); 91 (92.9%) of these improved after CABG. One hundred nine of t he 111 segments that showed no improvement with milrinone did not improve a fter revascularization (98.2%). Seventy-three segments were akinetic or dys kinetic at baseline; 46 (63.0%) of these improved with milrinone. Improveme nt in regional wall. motion after revascularization was detected in 84.8% o f the segments that improved with milrinone versus only 3.7% of the segment s that did not improve with milrinone. In patients with ischemic cardiomyop athy, improvement in left ventricular function (segmental wall motion and g lobal ejection fraction) during milrinone infusion is highly predictive of improvement after CABG.