Risk Factors for Myocardial Injury During Cardio-Pulmonary Bypass-Assisted Heart Surgery: A Retrospective...

Myocardial injury is a significant contributor to 30-day mortality after cardiac surgery with cardiopulmonary bypass. We aimed to investigate the association between mean arterial pressure, norepinephrine use during the aorta cross-clamp period, and aorta cross-clamp duration with myocardial injury during cardiopulmonary bypass-assisted open-heart surgery.

We identified all adults (≥ 18 years) undergoing coronary artery bypass grafting on cardiopulmonary bypass at Rigshospitalet, Copenhagen, between January 1st 2018 and December 31st 2019. The primary outcome was the change from baseline in creatine kinase myocardial band during the first 18 postoperative hours. Exposures included mean arterial pressure, norepinephrine use during the aorta cross-clamp period, and aorta cross-clamp duration. Associations were investigated using linear mixed-effect models.

A total of 1443 patients were included in the analysis. Patients treated with norepinephrine during the aortic cross-clamp period had 19% (95% CI: 9.0%-29%; p < 0.001) higher creatine kinase myocardial band postoperatively compared with those not treated with norepinephrine. Higher mean arterial pressure was not significantly associated with creatine kinase myocardial band (3.0%, 95% CI: -2.0% to 9%; p = 0.20). Patients treated with norepinephrine with a mean arterial pressure above the median (39 mmHg) had similar creatine kinase myocardial band levels compared to patients not treated with norepinephrine with a mean arterial pressure below the median, with a difference of 2% (95% CI: -0.18% to 0.22%, p = 0.80). Creatine kinase myocardial band increased by 12% (95% CI: 10%-14%; p < 0.001) for each 15-min increase in aortic cross-clamp duration.

This retrospective observational study suggested a possible link between norepinephrine use and myocardial injury during cardiopulmonary bypass-assisted open-heart surgery, while mean arterial pressure appeared to have no impact. Further randomized controlled trials are necessary.

In this single center retrospective cohort analysis, intraoperative cardiac surgery management factors were analyzed along with postoperative cardiac injury marker levels. Associations for aortic cross-clamp time, noradrenaline use during this, and mean arterial pressures are presented for post-op creatine kinase MB levels.