Objective To explore the clinical characteristics and short-term prognosis of postoperative acute myocardial infarction (PAMI) after cardiac surgery.

Methods A retrospective study was conducted on 45 PAMI patients who underwent coronary angiography after cardiac surgery at Zhongshan Hospital, Fudan University, from February 2015 to February 2025. General information, type of surgery, onset time and causes of PAMI, and in-hospital recovery condition were collected. Univariate logistic regression was used to analyze factors related to in-hospital survival.

Results The patients’ age was (62.40±11.72) years, 31 cases (68.89%) were male, 21 cases (46.67%) had hypertension. Twenty-six patients (57.78%) underwent cardiac valve surgery, and 16 patients (35.56%) received coronary artery bypass grafting. The onset time of PAMI was 24 (0, 48) hours, with 38 cases (84.44%) developing within 48 hours after surgery. Twenty-eight patients (62.22%) presented with new lesions in coronary arteries/bypass grafts, and 20 patients (44.44%) were considered to have thrombus-induced PAMI. Nine patients died in hospital, 13 patients failed to recover and were discharged automatically, and 23 patients were discharged after recovery. Univariate logistic regression analysis showed that new lesion in coronary arteries/bypass grafts was risk factor for in-hospital survival (OR=0.235, P=0.036).

Conclusions PAMI frequently occurs within 48 hours post-cardiac surgery, and thrombosis is the most common cause of PAMI. New lesions in coronary arteries/bypass grafts are closely correlated with poor short-term prognosis.