Acute myocardial infarction complicated by systemic hypoperfusion without hypotension: Report of the SHOCK trial registry

BACKGROUND: Cardiogenic shock is usually characterized by inadequate cardia c output and sustained hypotension. However, following a large myocardial i nfarction, peripheral hypoperfusion can occur with relatively well maintain ed systolic blood pressure, a condition known as nonhypotensive cardiogenic shock. The aim of this study was to determine the characteristics of patie nts with this condition. METHODS: The SHOCK trial registry prospectively enrolled patients with susp ected cardiogenic shock complicating acute myocardial infarction. We identi fied a group of 49 patients who presented with nonhypotensive shock, define d as clinical evidence of peripheral hypoperfusion with a systolic blood pr essure >90 mm Hg without vasopressor circulatory support. Clinical characte ristics, hemodynamic data, and outcomes in these patients were compared wit h a group of 943 patients with classic cardiogenic shock with hypotension. The age, gender, and distributions of coronary risk factors were similar in both groups. RESULTS: Patients with nonhypotensive shock were more likely to have an ant erior wall myocardial infarction (71% versus 53%, P = 0.03). Both groups of patients had similar rates of treatment with thrombolytic therapy, angiopl asty, and bypass surgery. Patients with nonhypotensive shock had an in-hosp ital mortality rate of 43% as compared with a rate of 66% among patients wh o had classic cardiogenic shock with hypotension (P = 0.001). Mortality amo ng 76 patients who presented with a systolic blood pressure <90 mm Hg but n o hypoperfusion was 26%. CONCLUSIONS: Even in the presence of normal blood pressure, clinical signs of peripheral hypoperfusion, which may be subtle, are associated with a sub stantial risk of in-hospital death following acute myocardial infarction. A m J Med. 2000;108: 374-380. (C) 2000 by Excerpta Medica, Inc.