TRANSVALVULAR LEFT-VENTRICULAR ASSISTANCE IN CARDIOGENIC-SHOCK SECONDARY TO ACUTE MYOCARDIAL-INFARCTION - EVIDENCE FOR RECOVERY FROM NEAR-FATAL MYOCARDIAL STUNNING

Objectives. The purpose of this study was to test the hypothesis that transvalvular left ventricular assistance would support the circulatio n in patients with cardiogenic shock secondary to acute myocardial inf arction and allow recovery of function in patients with a reversibly d amaged (stunned) left ventricle.Background. Cardiogenic shack occurs i n 7.5% of patients presenting with acute myocardial infarction, result ing in survival of only 20%. Despite the use of aggressive interventio nal therapy in patients with shock secondary to anterior myocardial in farction, survival remains as low as 33%. Methods. We studied 11 patie nts with acute myocardial infarction and cardiogenic shock, as defined by a cardiac index <2 liters/min per m(2), pulmonary capillary wedge pressure >18 mm Hg and systolic blood pressure <90 mm Hg during positi ve inotropic therapy. Patients were 57 +/- 13 years old (mean +/- SD) and had a mean left ventricular ejection fraction of 25 +/- 11%, mean arterial pressure of 69 +/- 13 mm Hg and mean cardiac index of 1.6 +/- 0.4 liters/min per m(2) on admission to the study. Results. During th e 1st 24 h of left ventricular assistance, pulmonary capillary wedge p ressure decreased from 26 +/- 4 to 16 +/- 4 mm Hg (p = 0.01), cardiac index increased from 1.6 +/- 0.4 to 2.4 +/- 0.4 liters/min per m(2), a nd the dopamine hydrochloride dose decreased from 51 +/- 92 to 18 +/- 12 mu g/kg body weight per min. In survivors, cardiac index improved t o 3.2 +/- 0.5 liters/min per m(2) (p = 0.01), and left ventricular eje ction fraction improved to 34 +/- 5% (p < 0.05). The overall survival in the study group was 4 (36%) of 11 patients (95% confidence interval [CI] 8% to 65%), and 4 (66%) of 6 patients (95% CI 29% to 100%) with a Q wave anterior myocardial infarction survived. Conclusions. Transva lvular left ventricular support during cardiogenic shock complicating acute myocardial infarction is feasible and results in significant hem odynamic and functional improvement.