# Preoperative Mechanical Ventilation Prior to Surgical Repair for Type A Aortic Dissection: Incidence, Risk, and Outcomes

## TL;DR

About 9% of patients with type A aortic dissection need preoperative mechanical ventilation, which is linked to higher in-hospital mortality but not long-term survival differences.

## Contribution

This study is the first to analyze the incidence and outcomes of preoperative mechanical ventilation in a large European registry of type A aortic dissection patients.

## Key findings

- Preoperative mechanical ventilation was required in 9.3% of patients with type A aortic dissection.
- IMV patients had a 38% in-hospital mortality rate, significantly higher than the 15% in non-IMV patients.
- Surgery extending to the aortic arch was associated with increased in-hospital mortality among IMV patients.

## Abstract

Objectives: Several conditions associated with type A aortic dissection may require preoperative invasive mechanical ventilation (IMV). The current literature lacks data on this subset of patients’ prevalence and postoperative outcomes. This study aims to investigate this unexplored issue in a multicenter European registry. Methods: Data from 3735 patients included in the European Registry of Type A Aortic Dissection (ERTAAD) were the subject of this analysis. Bootstrapped Least Absolute Shrinkage and Selection Operator (LASSO) logistic regression was performed for variable selection to identify key predictors of hospital death. In the second step, a multilevel multivariable logistic regression (MMLR) was carried out, given the clustered structure of the data. Results: A total of 346 (9.3%) out of 3735 patients required preoperative IMV. Compared to the non-IMV patients, patients requiring IMV had a significantly higher rate of organ malperfusion (52% vs. 35%, p < 0.001) and a higher proportion of tears in the aortic root (p = 0.048). The in-hospital mortality rate among IMV patients was 38% vs. 15% in non-IMV patients (p < 0.001), without a difference in post-discharge survival (p = 0.84). At the MMLR, patients who required IMV had 135% higher odds of in-hospital death compared to the remaining patients. IMV yielded the second highest odds in the prediction model for in-hospital mortality (OR 2.13, CI 1.60 to 2.85, p < 0.001). Among IMV patients, the extension of surgery to the aortic arch was significantly associated with increased in-hospital mortality (p < 0.001, OR 2.98). In multivariable analysis, preoperative IMV was independently associated with increased odds of in-hospital mortality. Conclusions: The need for invasive mechanical ventilation before surgical repair for type A aortic dissection is not infrequent. In this subpopulation, the in-hospital mortality rate was twofold compared to patients who did not require IMV. The awareness of the preoperative risk profile and outcomes of this subset of patients should urge surgeons to tailor the surgical strategy more appropriately to improve the immediate postoperative results.