# Long-Term Survival after Coronary Artery Surgical Revascularization—Does Ambient Temperature Matter?

## TL;DR

This study shows that high night-time temperatures, called tropical nights, may increase long-term mortality risk in patients who had heart surgery.

## Contribution

The study identifies tropical nights as a novel environmental risk factor for long-term mortality after coronary surgery.

## Key findings

- Dyslipidaemia, kidney disease, age, and BMI were significant predictors of late mortality.
- Tropical nights were found to be a significant environmental risk factor for long-term mortality.
- Ambient temperature exposure was linked to all-cause mortality in surgical revascularization patients.

## Abstract

Background and Objectives: The progression of global warming results in an increased exposure to extreme heat, leading to exaggeration of preexisting diseases and premature deaths. The aim of the study was to present possible risk factors for all-cause long-term mortality in patients who underwent surgical revascularization, including an assessment of the influence of ambient temperature exposure. Materials and Methods: Retrospective analysis included 153 (123 (80%) males and 30 (20%) females) patients who underwent off-pump revascularization and were followed for a median time of 2533 (1035–3250) days. The demographical, clinical data and ambient temperature exposure were taken into analysis for prediction of all-cause mortality. Individual exposure was calculated based on the place of habitation. Results: In the multivariate logistic regression model with backward stepwise elimination method, risk factors such as dyslipidaemia (p = 0.001), kidney disease (p = 0.005), age (p = 0.006), and body mass index (p = 0.007) were found to be significant for late mortality prediction. In addition to traditional factors, environmental characteristics, including tropical nights (p = 0.043), were revealed to be significant. Conclusions: High night-time ambient temperatures known as tropical nights may be regarded as additional long-term mortality risk factor after surgical revascularization.