Context Cardiogenic shock (CS) is the leading cause of death for patients hospitalized
with acute myocardial infarction (AMI).
Objective To assess the effect of early revascularization (ERV) on 1-year survival
for patients with AMI complicated by CS.
Design The SHOCK (Should We Emergently Revascularize Occluded Coronaries for
Cardiogenic Shock) Trial, an unblinded, randomized controlled trial from April
1993 through November 1998.
Setting Thirty-six referral centers with angioplasty and cardiac surgery facilities.
Patients Three hundred two patients with AMI and CS due to predominant left ventricular
failure who met specified clinical and hemodynamic criteria.
Interventions Patients were randomly assigned to an initial medical stabilization
(IMS; n = 150) group , which included thrombolysis (63% of patients), intra-aortic
balloon counterpulsation (86%), and subsequent revascularization (25%), or
to an ERV group (n = 152), which mandated revascularization within 6 hours
of randomization and included angioplasty (55%) and coronary artery bypass
graft surgery (38%).
Main Outcome Measures All-cause mortality and functional status at 1 year, compared between
the ERV and IMS groups.
Results One-year survival was 46.7% for patients in the ERV group compared with
33.6% in the IMS group (absolute difference in survival, 13.2%; 95% confidence
interval [CI], 2.2%-24.1%; P<.03; relative risk
for death, 0.72; 95% CI, 0.54-0.95). Of the 10 prespecified subgroup analyses,
only age (<75 vs ≥ 75 years) interacted significantly (P<.03) with treatment in that treatment benefit was apparent only
for patients younger than 75 years (51.6% survival in ERV group vs 33.3% in
IMS group). Eighty-three percent of 1-year survivors (85% of ERV group and
80% of IMS group) were in New York Heart Association class I or II.
Conclusions For patients with AMI complicated by CS, ERV resulted
in improved 1-year survival. We recommend rapid transfer of patients
with AMI complicated by CS, particularly those younger than 75 years,
to medical centers capable of providing early angiography and