BOSTON — Patients with advanced heart failure often receive a mechanical circulatory support device too late, when they have already begun to have multiorgan failure that is irreversibly fatal.
That was one lesson drawn from data collected on 420 patients who received a mechanical circulatory support (MCS) device at any of 75 U.S. centers that participated in a registry during June 2006-December 2007, Dr. William L. Holman said at the annual meeting of the International Society for Heart and Lung Transplantation.
The overall 6-month mortality of the 420 patients reviewed by Dr. Holman was 25%, but the mortality rates were especially high among patients who required biventricular support—an indication that they had right-ventricular as well as left-ventricular failure—and in patients with elevated bilirubin (defined as greater than 1 mg/dL) or ascites. Such elevations in these patients are caused by worsening right-ventricular failure and poor right-ventricular filling, a condition that in turn is caused by prolonged and worsening left-ventricular failure. They are also indicators that multiorgan failure is occurring as a consequence of impaired systemic circulation caused by poor right-ventricular function, said Dr. Holman, a professor of cardiothoracic surgery at the University of Alabama at Birmingham.
Patients often deteriorate to this state by the time they are referred for an MCS device because they have not been followed frequently enough or treated in a timely manner with the full range of medical treatments that have been proved to slow the worsening of heart failure, said Dr. Raymond L. Benza, a cardiologist and director of the pulmonary vascular disease program at the University of Alabama at Birmingham.
Among patients in the INTERMACS registry, the 59 patients with detectable ascites had a 43% mortality rate during the 6 months after receiving an MCS device, compared with a 20% rate in patients without ascites. Among the 218 patients with a bilirubin level greater than 1 mg/dL, the mortality rate was 32%, compared with a 16% rate in patients with a level of 1 mg/dL or less.
A multivariate analysis that controlled for demographic and clinical variables identified these and other factors (cardiogenic shock, placement of a total artificial heart) as significant risk factors for death in the Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS). (See box.)
INTERMACS is supported by the Food and Drug Administration and the Centers for Medicare and Medicaid Services, and allows registration of U.S. patients who receive an FDA-approved MCS device.
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