Intraoperative Hypotension and Myocardial Infarction Development Among High-Risk Patients Undergoing Noncardiac Surgery

A Nested Case-Control Study

Linn Hallqvist, MD, PhD Student, DESA; Fredrik Granath, PhD; Michael Fored, MD, PhD; Max Bell, MD, PhD


Anesth Analg. 2021;133(1):6-15. 

In This Article


This project is unique considering the extensive source population, enabling extraction of validated MI cases within a prespecified period (30 days) after surgery and selection of matched controls. Using high-resolution data from a Swedish Quality Registry and the NPR, we identified MI type 1 and the symptomatic MI type 2, even though not referred to cardiology clinics or subject to cardiac intervention. All cases with MI diagnoses were validated, and the exact date of MI development was obtained using electronic medical records. Data included preoperative baseline SBP and intraoperative values, enabling comparison of different IOH definitions. A validation trial has previously been performed to evaluate BP recordings (Supplemental Digital Content 2, BP Validation, An important consideration is that our cases and controls are sampled from a well-characterized surgery cohort.[18] This allows estimation of the proportion of patients exposed to IOH events in the population, from our controls, and we are able to transfer the relative risk to a corresponding absolute risk increases, even though this is a case-control designed study. The risk-group distribution of cases and controls were available and information of postoperative day of MI development. Analyses suggest additional effect of hypotension in patients belonging to higher risk groups and in MI cases diagnosed within 2 days of surgery.