Heart attack victims who survive to leave the hospital have a 5 to 10 percent risk of dying suddenly within the next 12 months. Use of amiodarone medication or implantable cardioverter defibrillators (ICDs) to prevent ventricular arrhythmias in heart attack patients with severely depressed functioning of the heart's left ventricle may extend their lives, according to a study supported by the Agency for Healthcare Research and Quality (HS08362). The researchers examined how the efficacy of these prophylactic interventions would affect their cost-effectiveness.
This assessment, based on a theoretical model, highlights the importance of ongoing clinical trials of ICDs and amiodarone in patients who have had heart attacks, note Gillian D. Sanders, Ph.D., lead author, and Mark A. Hlatky, M.D., principal investigator, both of Stanford University. Their model was based on estimated survival, cardiac death, and inpatient costs included in the Myocardial Infarction, Triage, and Intervention Registry, as well as data derived from research studies. They compared the effects of ICD or amiodarone to no treatment for extending life years, quality-adjusted life years (QALYs), costs, and cost-effectiveness for patients who had previously suffered a heart attack but had not experienced sustained ventricular arrhythmia.
Compared with no treatment, ICD use was predicted to lead to the greatest gains in QALYs and the highest expenditures. Amiodarone use would result in intermediate QALYs and costs. With $75,000/QALY taken as the criterion, ICDs or amiodarone would be cost effective compared with no therapy in patients with severely depressed left ventricular function as long as ICDs reduced arrhythmic death by 50 percent, and amiodarone reduced total death by 7 percent. Neither approach seemed likely to be cost effective in patients with well-preserved ventricular function, unless amiodarone were to be extremely effective in reducing total mortality (greater than 15 percent). Amiodarone generally would be more cost effective than the ICD.
See "Potential cost-effectiveness of prophylactic use of the implantable cardioverter defibrillator or amiodarone after myocardial infarction," by Dr. Sanders, Dr. Hlatky, Nathan R. Every, M.D., and others, in the November 2001 Annals of Internal Medicine 135, p. 870-883.