Circulatory support for cardiogenic shock due to acute myocardial infarction: A Canadian experience

BACKGROUND: Cardiogenic shock due to acute myocardial infarction (AMI) is a ssociated with high mortality. Circulatory support devices may be used to a ssist these patients while they await cardiac transplantation. METHODS AND RESULTS: From 1986 to 1997, 25 patients in cardiogenic shock co mplicating AMI within 3.6+/-0.1 days of the event were supported with artif icial hearts. Of the 25 patients, 21 were men with a mean age of 48.4+/-1.8 years. The age range was 26 to 62 years. Patients were considered for a de vice when the following criteria were met: cardiac index less than 1.8 L/mi n/m(2), wedge pressure greater than 20 mmHg despite one or two inotropes an d/or intra-aortic balloon support. They received either a CardioWest total artificial heart (n=13), a Thoratec biventricular assist device (n=6) or le ft ventricular assist device (LVAD) (n=6). Three patients were not consider ed transplant candidates and died while on the devices (two with multiorgan failure and one found to have a bronchogenic carcinoma after implant), wit h 22 undergoing cardiac transplantation within 8.6+/-2.2 days of device imp lant. Six patients died in hospital after the transplants (27.3% mortality) . Complications included bleeding or tamponade in seven (28%), pneumonia in six (24%) and right ventricular failure in three LVAD patients (12%). Post -transplant actuarial one-, two- and five-year survival rates were 71.4%, 7 1.4% and 51%, respectively. CONCLUSIONS: Circulatory support devices offer a means to maintain organ pe rfusion in patients who develop cardiogenic shock due to AMI. Patients can then undergo transplantation with a reasonable expectation for survival whe n the alternative is death. Eventually the availability of permanent suppor t devices may obviate the need for transplant in these patients.