Perioperative (N)STEMI after Cardiac Surgery: Differences in Decision Making for Intervention

Objective: Detection and management of suspected perioperative myocardial infarction (PMI) after cardiac surgery still remains crucial. Whereas postoperative ST-Elevation (STEMI) should be immediately investigated by angiography, indication in secondary increase of cardiac biomarkers (NSTEMI) is ambiguous.

Methods: All patients after cardiac surgery are monitored by electrocardiogram and sequential cardiac biomarker testing (CKMB). Angiography was performed when ST-Elevation occurred. NSTEMI was defined as secondary increase of cardiac biomarkers i.e., CKMB level exceeding 100 U/l. In these patients angiography was indicated on first postoperative day.

Results: Between 1/2013 and 8/2014 in 81 patients these conditions occurred and in 84% (68 pts.) heart catheterisation was performed. Mean age of this cohort was 66.9 ± 9.3 years, and 74% had isolated coronary artery bypass grafting (CABG) during primary surgery. Angiography revealed in 45 pts (66%) graft dysfunction, in 23 pts (34%) no dysfunction was detected. STEMI or NSTEMI were independent predictors of bypass dysfunction (p = 0.25). In a heart team approach therapeutic interventions included conservative approach, operative correction, and stent implantation, which were indicated in 44%, 40% and 16%, respectively. Mortality was 3.7% and did not differ between revision techniques. Nevertheless, bypass dysfunction was significantly more often seen in patients with isolated CABG versus concomitant procedures (87% versus 13%, p < 0.001).

Conclusion: Both, NSTEMI and STEMI indicate perioperative myocardial infarction with a high incidence of graft dysfunction, especially in isolated CABG procedures. In concomitant CABG procedures ST elevation or increase of cardiac biomarkers are not adequate for decision making and further parameters are warranted.