[Exercise capacity in children late after aortic valve replacement using the Konno procedure]

Area of Science:

• Cardiology
• Pediatric Cardiac Surgery
• Exercise Physiology

Background:

• The Konno procedure is a surgical technique for aortic valve replacement.
• Long-term outcomes and potential latent issues after this procedure in pediatric patients require further investigation.

Purpose of the Study:

• To evaluate the exercise capacity and identify potential latent problems in patients who underwent the Konno procedure for aortic valve replacement.

Main Methods:

• Exercise stress tests using a bicycle ergometer with a ramp protocol were conducted on 6 patients (3 males, 3 females).
• Gas exchange responses were measured using the mixing chamber method.
• Patients' ages at operation (mean 6.6 years) and exercise testing (mean 11.4 years) were recorded.

Main Results:

• All patients were in New York Heart Association (NYHA) class I, with two exhibiting residual pulmonary hypertension (PH).
• Maximum oxygen consumption (VO2 max) ranged from 37-39 ml/kg/min in males and 23-34 ml/kg/min in females.
• Patients with residual PH showed heart rate (HR) bursting and O2 pulse plateau/decline, suggesting decreased stroke volume.

Conclusions:

• Patients late after the Konno procedure demonstrated exercise tolerance beyond respiratory compensation without arrhythmias.
• Heart rate increased satisfactorily during exercise, but maximum oxygen consumption was approximately 70% of normal levels.
• The Konno procedure appears safe for exercise, though reduced maximal oxygen uptake may indicate latent cardiovascular compromise.