EFFECTS OF RHEOTHRX ON MORTALITY, MORBIDITY, LEFT-VENTRICULAR FUNCTION, AND INFARCT SIZE IN PATIENTS WITH ACUTE MYOCARDIAL-INFARCTION

Background Previous studies suggested that RhetothRx (poloxamer 188) r educes infarct size and improves left ventricular (LV) function in acu te myocardial infarction (AMI). We therefore evaluated the effects of various doses of RheothRx in 2948 patients presenting with AMI. Method s and Results Patients were randomized to a control group (n=963) or t o receive RheothRx. Patients receiving RheothRx were allocated to rece ive a 1-hour bolus only (regimen A. n=844), an additional 11-hour infu sion at a low dose (target serum concentration of 0.5 mg/mL) (regimen Y, n=490), or an additional 23-hour infusion at a low dose (regimen B, n=483). Three higher doses (1-hour bolus+low-dose infusion for 47 hou rs. 1-hour bolus+high dose, target serum concentration of 1.0 mg/mL fo r 14 hours, or 1-hour bolus+high dose for 48 hours) were discontinued because of high rates of renal dysfunction (8.8%). Renal dysfunction w as also observed at lower doses (regimen A. 3.1%; Y, 2.7%; and B, 4.1% ) compared with the control patients (1.0%). There was no significant difference in the composite outcome of death, cardiogenic shock, or re infarction at 35 days (all RheothRx, 13.6%; control, 12.7%). There was a higher incidence of sinus tachycardia (24.7% versus 21.6%, P=.02), atrial flutter (3.0% versus 1.3%, P=.019), atrial fibrillation (10.2% versus 7.3%, P=.082), pericarditis (6.6% versus 4.7%, P=.055), and cli nical (21.9% versus 17.9%, P=.005) and radiological (15.3% versus 12.3 %, P=.12) evidence of heart failure. This was associated with a lower LV ejection fraction (n=1053) in treated patients (by approximate to - 0.02, P=.026), but there was little difference (P=.34) in infarct size (n=1088). Conclusions In this study of nearly 3000 patients, RheothRx had no effect on mortality, reinfarction, or cardiogenic shock and on adverse effect on renal function, LV ejection fraction, and various c linical manifestations of LV dysfunction or heart failure.