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

BACKGROUND

Cardiogenic shock is usually characterized by inadequate cardiac output and sustained hypotension. However, following a large myocardial infarction, peripheral hypoperfusion can occur with relatively well maintained systolic blood pressure, a condition known as nonhypotensive cardiogenic shock. The aim of this study was to determine the characteristics of patients with this condition.

METHODS

The SHOCK trial registry prospectively enrolled patients with suspected cardiogenic shock complicating acute myocardial infarction. We identified a group of 49 patients who presented with nonhypotensive shock, defined as clinical evidence of peripheral hypoperfusion with a systolic blood pressure >90 mm Hg without vasopressor circulatory support. Clinical characteristics, hemodynamic data, and outcomes in these patients were compared with 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 anterior wall myocardial infarction (71% versus 53%, P = 0.03). Both groups of patients had similar rates of treatment with thrombolytic therapy, angioplasty, and bypass surgery. Patients with nonhypotensive shock had an in-hospital mortality rate of 43% as compared with a rate of 66% among patients who had classic cardiogenic shock with hypotension (P = 0.001). Mortality among 76 patients who presented with a systolic blood pressure <90 mm Hg but no 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 substantial risk of in-hospital death following acute myocardial infarction.