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Circulatory support for cardiogenic shock due to acute myocardial infarction: a Canadian experience
P J Hendry1, R G Masters, T V Mussivand
1University of Ottawa Heart Institute, Ottawa, Canada. phendry@ottawaheart.ca
Insights
Artificial hearts and ventricular assist devices can support patients with acute myocardial infarction (AMI) cardiogenic shock. These circulatory support devices offer a bridge to cardiac transplantation, improving survival rates for critically ill patients.
Area of Science:
- Cardiology
- Mechanical Circulatory Support
- Cardiac Surgery
Background:
- Cardiogenic shock following acute myocardial infarction (AMI) presents a significant mortality risk.
- Mechanical circulatory support (MCS) devices are crucial for managing patients awaiting cardiac transplantation.
Purpose of the Study:
- To evaluate the efficacy of artificial hearts and ventricular assist devices (VADs) in patients with cardiogenic shock due to AMI.
- To assess outcomes and survival rates in patients bridged to cardiac transplantation with MCS devices.
Main Methods:
- A retrospective analysis of 25 patients with cardiogenic shock complicating AMI, supported by MCS devices between 1986 and 1997.
- Patients received either a total artificial heart (TAH), a biventricular assist device (BiVAD), or a left ventricular assist device (LVAD).
- Criteria for device consideration included low cardiac index and high wedge pressure despite medical management.
Main Results:
- Twenty-two of 25 patients (88%) underwent cardiac transplantation after a mean of 8.6 days on MCS.
- In-hospital mortality post-transplant was 27.3% (6 of 22 patients).
- Common complications included bleeding/tamponade (28%), pneumonia (24%), and right ventricular failure in LVAD patients (12%).
Conclusions:
- Circulatory support devices effectively maintain organ perfusion in AMI-induced cardiogenic shock.
- MCS provides a viable bridge to transplantation, offering a reasonable survival expectation for critically ill patients.
- Advancements in permanent support devices may reduce the future need for cardiac transplantation in these cases.
Background:
Cardiogenic shock due to acute myocardial infarction (AMI) is associated with high mortality. Circulatory support devices may be used to assist these patients while they await cardiac transplantation.
Methods And Results:
From 1986 to 1997, 25 patients in cardiogenic shock complicating AMI within 3.6+/-0.7 days of the event were supported with artificial 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 device when the following criteria were met: cardiac index less than 1.8 L/min/m2, wedge pressure greater than 20 mmHg despite one or two inotropes and/or intra-aortic balloon support. They received either a CardioWest total artificial heart (n=13), a Thoratec biventricular assist device (n=6) or left ventricular assist device (LVAD) (n=6). Three patients were not considered transplant candidates and died while on the devices (two with multiorgan failure and one found to have a bronchogenic carcinoma after implant), with 22 undergoing cardiac transplantation within 8.6+/-2.2 days of device implant. 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%, 71.4% and 51%, respectively.
Conclusions:
Circulatory support devices offer a means to maintain organ perfusion in patients who develop cardiogenic shock due to AMI. Patients can then undergo transplantation with a reasonable expectation for survival when the alternative is death. Eventually the availability of permanent support devices may obviate the need for transplant in these patients.