Off-pump versus on-pump myocardial revascularization in patients with ST-segment elevation myocardial infarction: a randomized trial.

OBJECTIVE: Conventional cardioplegic arrest coronary artery bypass grafting after ST-segment elevation myocardial infarction is associated with high mortality and morbidity. The benefits of off-pump surgery have been suggested. This study randomly evaluated the impact of the off-pump technique on clinical results.

METHODS: Between February 2002 and October 2007, 128 patients with ST-segment elevation myocardial infarction who underwent myocardial revascularization within 48 hours from the onset of symptoms were randomly assigned to 2 groups: on-pump group (66 patients/51.5%) and off-pump group (63 patients/48.5%). The primary end point was the incidence of in-hospital death and outcomes (low cardiac output syndrome, prolonged mechanical and pharmacologic cardiac support, prolonged mechanical ventilation support, and postoperative length of stay in intensive care unit and hospital). The secondary end point was the evaluation of myocardial infarct size measured by the perioperative serum release of cardiac troponin I and the improvement of contractile cardiac function evaluated by the wall motion score index.

RESULTS: Overall in-hospital mortality was 4.6%. In-hospital mortality was 7.7% (5 patients) in the on-pump group and 1.6% (1 patient) in the off-pump group (P = .04). Statistically significant differences were found between the 2 groups concerning the incidence of low cardiac output syndrome (P = .001), time of inotrope drugs support (P = .001), time of mechanical ventilation (P = .006), reoperation for bleeding (P = .04), intensive care unit stay (P = .01), and in-hospital stay (P = .02). Statistically significant differences also were found between the 2 groups concerning the incidence of in-hospital death in patients who were admitted to surgery in cardiac shock (P = .0018) and patients who underwent surgery within 6 hours from the onset of symptoms (P = .0026). The procedure in 1 patient (1.6%) in the off-pump group was converted to the on-pump beating heart technique. The serum levels of cardiac troponin I were high in the on-pump group during the first 48 hours after surgery. Myocardial function was better in the off-pump group. There were no cardiac-related late deaths, and patients had no recurrent cardiac events.

CONCLUSION: Off-pump surgery reduced early mortality and morbidity in patients with ST-segment elevation myocardial infarction in respect to the conventional procedure. Off-pump surgery showed better results than on-pump surgery in patients who underwent surgery within 6 hours from the onset of symptoms and in patients with cardiogenic shock.