Prediction of postoperative exercise tolerance after aortic valve replacement

Area of Science:

• Cardiovascular Surgery
• Cardiac Valve Disease
• Exercise Physiology

Background:

• Aortic valve replacement (AVR) sizing remains challenging, particularly in patients with small aortic annuli.
• Optimizing prosthetic valve size is crucial for restoring adequate cardiac function and patient quality of life.

Purpose of the Study:

• To assess the relationship between prosthetic valve size and postoperative exercise capacity in patients undergoing AVR.
• To identify preoperative predictors of good exercise capacity following isolated AVR with St. Jude Medical valves.

Main Methods:

• Evaluated exercise capacity using peak oxygen consumption (percentage of predicted) in 39 AVR patients (mean age, 56 years) at 2.2 years post-surgery.
• Utilized ergometer exercise testing and Doppler ultrasound to measure pressure gradients and valve area index.
• Correlated preoperative left ventricular dimensions and valve area index with postoperative exercise capacity.

Main Results:

• No significant correlation was found between resting peak oxygen consumption and transprosthetic pressure gradients.
• In aortic regurgitation, preoperative end-diastolic and end-systolic left ventricular dimensions inversely correlated with exercise capacity (p < 0.05).
• In aortic stenosis, a weak correlation was observed between valve area index and exercise capacity (p < 0.01).

Conclusions:

• For aortic regurgitation, preoperative end-systolic and end-diastolic left ventricular dimensions should be <50 mm and <70 mm, respectively, for optimal exercise capacity.
• For aortic stenosis, a valve area index >1.5 cm²/m² is likely necessary for achieving >80% of predicted peak oxygen consumption postoperatively.
• These preoperative parameters aid in selecting optimal aortic valve prosthesis size to improve long-term exercise performance.