# Worse risk profile, number of grafts and hospital death but acceptable late survival in females undergoing coronary surgery: a 20-year propensity matched analysis

## TL;DR

Women undergoing heart surgery have higher in-hospital risks and receive fewer grafts than men, but long-term survival is similar.

## Contribution

A 20-year propensity-matched study reveals sex-based differences in CABG outcomes and the protective effect of off-pump surgery in females.

## Key findings

- Females had higher in-hospital mortality and fewer grafts compared to males after matching.
- Long-term survival was similar between matched male and female patients.
- Off-pump CABG reduced in-hospital mortality risk in females.

## Abstract

To evaluate sex differences in perioperative characteristics, in-hospital outcomes and long-term survival following coronary artery bypass grafting (CABG).

Prospective data were collected for all patients undergoing isolated CABG at a single centre during 2001–2021. Baseline characteristics were adjusted between females and males using 1:1 propensity score matching (nearest-neighbour, without replacement). Kaplan-Meier analysis assessed long-term survival. A predefined sub-analysis assessed risk mitigation associated with using off-pump CABG (OPCABG) in females in the matched cohort.

Prematching, 11 563 males and 2573 females were included. Females were older with higher prevalences of class III–IV angina, hypertension and diabetes. After matching, 2573 patients per group were analysed, with standardised mean differences <0.1 for all covariates. Females had fewer left internal mammary artery (LIMA) grafts (84% vs 88%, p<0.001), fewer total grafts (median 2 vs 3, p<0.001), higher in-hospital mortality (2.2% vs 1.3%, OR 1.74, 95% CI 1.14 to 2.71, p=0.011) and longer hospital stays (median 7 days vs 6 days, beta 0.51, 95% CI 0.12 to 0.90, p=0.01). Long-term survival was similar (stratified log-rank p=0.79). OPCABG mitigated the risk of in-hospital mortality in females (1.1% males vs 1.6% females, OR 0.69, 95% CI 0.33 to 1.43, p=0.32; 1.6% OPCABG females vs 3.0% on-pump females, OR 0.53, 95% CI 0.31 to 0.91, p=0.021).

Females suffer higher in-hospital mortality and receive fewer LIMA and total number of grafts than males; however, 20-year survival is similar. OPCABG protects females from in-hospital mortality. A new female-tailored peri-operative care approach is warranted for females undergoing CABG.