Myocardial infarction after microvascular head and neck reconstruction

Microvascular flap transfer is a popular method for immediate reconstruction of defects in the head and neck resulting after the treatment of head and neck cancer. Head and neck cancer occurs most commonly in elderly patients with a high prevalence of heavy smoking. Surgery in this patient population is frequently prolonged and is associated with significant intraoperative blood loss. The present study seeks to identify factors contributing to perioperative myocardial infarction and to determine the best course of management.

Retrospective analysis of 193 consecutive free flap surgeries. METHODS A series of 193 microvascular free flaps performed over a 5-year period for reconstruction of defects in the head and neck was retrospectively analyzed to identify the incidence, management, and outcome of perioperative myocardial infarction in this patient population.

Myocardial infarctions occurred in seven patients, for an overall incidence of 3.6%. Statistical analysis using logistic regression failed to demonstrate any significant relationship between age, sex, total operative time, operative blood loss, net intraoperative fluid shifts, tumor stage, American Society of Anesthesiology (ASA) preoperative classification, type of free flap, and the occurrence of perioperative myocardial infarction. Hemodynamic instability manifested by hypotension occurred in four patients who had perioperative myocardial infarction. Three of these patients underwent urgent coronary artery bypass surgery, whereas one patient underwent urgent endovascular therapy with subsequent stabilization of the hemodynamic instability. All free flaps survived despite myocardial infarction and hemodynamic instability. Two patients (29%) died after postoperative intervals of 74 and 99 days, never having left the hospital.

Systemic hypotension is a well-recognized risk factor for free flap failure. Our experience suggests that aggressive intervention to reverse coronary ischemia associated with hemodynamic instability has a favorable outcome on free flap survival, and free flap thrombosis is not an inevitable outcome of the low-flow state associated with perioperative cardiopulmonary bypass. Although the overall incidence of perioperative myocardial infarction in patients undergoing microvascular head and neck reconstruction is low, patient mortality is high, so emphasis should be placed on preoperative identification of patients with coronary artery disease.