Evaluate the Value of Modified Shock Index in Predicting the Incidence of Cardiovascular Events After Non-cardiac Surgery in Cardiac Patients

This study aims to evaluate the efficacy of the modified shock index (MSI) in predicting postoperative cardiovascular events (PCEs) in cardiac patients undergoing non-cardiac surgery. A retrospective analysis was conducted on clinical data from patients who underwent gastrointestinal and hepatobiliary surgeries at Fujian Medical University Union Hospital between January 2020 and December 2025. Baseline characteristics, intraoperative vital signs, occurrence of cardiac complications, and total postoperative hospital stay were analyzed to determine the optimal MSI cutoff values, sensitivity, specificity, and Youden's index for PCE prediction. The study further elucidates pathophysiological mechanisms linking MSI thresholds to organ hypoperfusion, providing an evidence-based tool for individualized perioperative hemodynamic management.

Inclusion criteria

• (1) Age ≥45 years. (2) Underwent elective major abdominal surgery with a duration of ≥2 hours at Fujian Medical University Union Hospital between January 2020 and December 2025.

(3) Presence of any of the following: history of heart disease; elevated BNP or cardiac troponin within 30 days before surgery; or at least two cardiac risk factors.

(4) Complete electronic medical records available.

Exclusion criteria

• (1) ASA ≥ V. (2) Acute cardiovascular event. (3) Severe uncontrolled hypertension. (4) End-stage renal disease. (5) Sepsis. (6) Preoperative requirement for vasopressor support. (7) Pregnancy. (8) Missing >20% of key clinical data. (9) Loss to follow-up or refusal to consent to the use of medical records.