In patients with ST-segment elevation myocardial infarction (STEMI), timely reperfusion with primary percutaneous coronary intervention (PCI) is the preferred treatment. In primary PCI patients with multivessel disease, it is unclear whether culprit vessel PCI only is the preferred treatment. We compared mortality among (1) STEMI patients with single-vessel disease and those with multivessel disease and (2) multivessel disease patients with and without additional revascularization of nonculprit lesions within 2 months after the index PCI.

From January 2002 to June 2009, all patients presenting with STEMI and treated with primary PCI were identified from the Western Denmark Heart Registry, which covers a population of 3.0 million. The hazard ratio (HR) for death was estimated using a Cox regression model, controlling for potential confounding.

The study cohort consisted of 8,822 patients: 4,770 (54.1%) had single-vessel disease and 4,052 (45.9%) had multivessel disease. Overall, 1-year cumulative mortality was 7.6%, and 7-year cumulative mortality was 24.0%. Multivessel disease was associated with higher 7-year mortality (adjusted HR 1.45 [95% CI 1.30-1.62], P < .001). Among patients with multivessel disease, lack of additional revascularization beyond the culprit lesion was associated with higher 7-year mortality (adjusted HR 1.50 [95% CI 1.25-1.80], P < .001). In patients with multivessel disease who underwent additional revascularization, 7-year mortality (adjusted HR 1.01 [95% CI 0.84-1.22], P = .89) was similar compared to patients with single-vessel disease.

In STEMI patients, multivessel disease was associated with a higher mortality compared to single-vessel disease. In multivessel disease patients, additional revascularization was associated with a higher survival compared with culprit vessel PCI only.