Long-term outcomes among older patients with non-ST-segment elevation myocardial infarction complicated by cardiogenic shock

Background Cardiogenic shock complicating acute myocardial infarction (MI) in older patients is associated with a high risk of inhospital mortality; however, the long-term prognosis among these patients who survive the index hospitalization is uncertain. Methods We evaluated 42,656 patients 65 years or older with non-ST-segment elevation MI from the CRUSADE Registry treated at 448 hospitals in the United States from 2003 to 2006 and linked to Medicare longitudinal claims data. Among patients who survived to hospital discharge, Cox proportional hazards modeling was used to compare survival between patients with and without inhospital shock. The secondary outcome of "percent days alive and out of hospital" (%DAOH) was also compared between the 2 groups. Results Overall, 2,001 (4.7%) patients had shock on presentation and/or developed shock during the index hospitalization. Inhospital mortality rates among those with and without shock were 39.1% versus 4.5% (P <.001). Among the 40,036 index hospital survivors, postdischarge survival curves diverged early with lower survival (48.1% [95% CI 45.0-51.2] vs 56.5% [95% CI 56.0-57.1], P <.001) and lower %DAOH (65.5% ± 40.6% and 73.4% ± 36.8 %, P <.001) among patients with shock through 4 years. Based on the observation of parallel survival curves starting 6 months postdischarge, we performed landmark analyses and found no difference in mortality (hazard ratio 1.02, 95% CI 0.91-1.14) or %DAOH (79.7% ± 32.0% vs 81.3% ± 31.0%, P =.17) beyond 6 months between those with and without shock. Conclusions Our results highlight the time-dependent hazard of risk during the early postdischarge period for older patients with non-ST-segment elevation MI and cardiogenic shock that appears to be mitigated after 6 months, thereby lending support for the examination of new therapies designed to ameliorate this early risk.