The researchers used a sophisticated computer model to calculate the potential impact of using the test, called microvolt T-wave alternans (MTWA), to help determine which patients would benefit most from implanted devices that automatically re-start a stopped heart.
Those devices, called implantable cardioverter defibrillators, or ICDs, have been shown to save lives that would otherwise have been lost to sudden cardiac death, which kills 300,000 Americans each year.
One year ago, Medicare expanded its coverage of ICDs to include many more heart patients; an estimated 500,000 people over age 65 are now candidates. Covering the cost of ICDs for patients who have the same characteristics as participants in the MADIT-2 ICD trial that led to Medicare approval could add $3 billion annually to the program's budget. ICDs cost $35,000 including implantation, require periodic battery replacement, and pose a device failure risk.
In a presentation at the American College of Cardiology Scientific Session, the U-M team suggests that the MTWA test could spare a significant fraction of those costs, if doctors focused on providing ICDs only to patients with an abnormal or inconclusive MTWA test result. Previous studies have suggested that patients with a negative, or normal, MTWA test result have a far lower risk of sudden cardiac death than others.
This risk-stratification of ICD candidates who meet MADIT-2 criteria, say the U-M researchers, could potentially save Medicare $690 million a year -- even after the cost of the MTWA test and the care of patients who don't receive ICDs are included.