Effects of vasodilator therapy for severe pump failure in acute myocardial infarction on short-term and late prognosis.

Abstract

Forty-three patients with severe pump failure complicating acute myocardial infarction were treated with vasodilators (nitroprusside (40) and phentolamine (3)) for four hours to 27 days. Cardiac index, stroke volume index, and stroke work index (SWI) increased while the left ventricular filling pressure (LVFP) decreased during vasodilator therapy. Twenty-four of the 43 patients (56%) survived. Of patients with initial SWI between 11-20 gm-m/m2 and LVFP less than 15 mm Hg, 68% survived. In contrast only 18% of patients with SWI of 10 gm-m/m2 or less and LVFP greater than 15 mm Hg survived. Of the 17 patients with clinical shock, 8 (47%) survived. All 24 patients discharged from the hospital were followed for at least 12 months. Fourteen patients died one to 25 months (average 9.2 months) after discharge and the cause of death was pump failure in ten of them (71%). The ten survivors at last follow-up had been followed for 15 to 32 months (average 24 months). The cumulative survival at 24 months was 28%. Thus, despite improvement in short-term prognosis with vasodilator therapy in patients with severe pump failure complicating acute myocardial infarction, the prognosis for long term survival remains unfavorable, possibly due to severe intrinsic cardiac damage.