# Retrospective Evaluation of Acute Postoperative Complications Occurring in the ICU Following Canine Mitral Valve Repair Surgery Under Cardiopulmonary Bypass (2019–2020): 41 Cases

## TL;DR

This study examines postoperative complications in dogs after heart valve surgery, finding that most dogs experience significant issues requiring special care.

## Contribution

The study provides the first exploratory analysis of complications in dogs undergoing mitral valve repair at a single veterinary hospital.

## Key findings

- 75.6% of dogs experienced clinically relevant postoperative complications.
- Excessive pleural hemorrhage and increased red cell transfusion requirement were linked to reduced odds of hospital discharge survival.
- Neurological complications were strongly associated with poor outcomes in ICU discharge and survival.

## Abstract

To describe abnormalities and clinically relevant complications in dogs following mitral valve repair. Secondarily, to assess demographic and intraoperative factors with clinically relevant complications, length of ICU stay, successful ICU discharge, and survival to hospital discharge. Finally, to analyze the relationship of clinically relevant complications with prolonged ICU stay, successful ICU discharge, and survival to hospital discharge.

Retrospective observational study, May 2019 to January 2020.

University veterinary teaching hospital.

Forty‐one dogs following mitral valve repair.

Medical records were retrospectively reviewed. Abnormalities occurred in all dogs. All dogs received red blood cell transfusions, exhibited postoperative pleural hemorrhage, and had increased C‐reactive protein concentration. Common abnormalities included anemia, hypoalbuminemia, pulmonary dysfunction, acidemia, hypokalemia, ventricular premature complexes, hypernatremia, and corrected hyperchloremia. Clinically relevant complications occurred in 75.6% of dogs, with the most common being hyperlactatemia, increased red cell transfusion requirement, excessive pleural hemorrhage, IV fluid bolus requirement, postoperative furosemide administration, and severe hypernatremia. Several complications had altered odds for prolonged ICU hospitalization, successful ICU discharge, and survival to hospital discharge; those with appropriately narrow confidence intervals (CIs) included excessive pleural hemorrhage and increased red cell transfusion requirement, both having reduced odds of survival to hospital discharge (odds ratio [OR] 0.08, 95% CI 0.01–0.58 and OR 0.04, 95% CI 0.00–0.42, respectively). Neurological complications were negatively associated with successful ICU discharge (p = 0.004) and survival to hospital discharge (p = 0.002). Revision surgery was associated with reduced odds of survival to hospital discharge (OR 0.06, 95% CI 0.00–0.80).

Postoperative abnormalities are common in dogs undergoing mitral valve repair, with many expected given the nature of surgery performed. Many dogs experienced complications requiring deviation from standard protocol. This study provides the first exploratory analysis of dogs undergoing mitral valve repair at a single center.