The IRIS trial: no survival benefit from early ICD implantation following risk stratification after myocardial infarction. This adds little to what we already knew and does not suggest changes in current guideline recommendations for device therapy.
Sudden cardiac death was reduced but there was a corresponding increase in non-arrhythmic death so that all cause mortality was unaffected. These discordant findings are poorly understood but it was suggested that these patients stratified early on were at high risk for both arrhythmic death and pump failure, and device therapy merely exchanged one mode of death for another. Also, as is apparent from the Medscape-Heartwire report, selection criteria were unusual, resulting in a mixed bag of study patients which differed from those for whom device therapy is currently recommended based on MADT II and other trials that support current guidelines.
Finally and perhaps most importantly, IRIS, which looked at patients one month or less post MI, confirms what we previously learned several years ago from DINAMIT, which showed no reduction in all cause mortality by device therapy in patients selected for treatment within 40 days post MI. That was the basis for the current guideline recommendations:
ICD therapy is indicated in patients with LVEF less than 35% due to prior MI who are at least 40 days post-MI and are in NYHA functional Class II or III. (Level of Evidence: A).
ICD therapy is indicated in patients with LV dysfunction due to prior MI who are at least 40 days post-MI, have an LVEF less than 30%, and are in NYHA functional Class I (Level of Evidence: A).
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