Comprehensive Use of Cardiopulmonary Exercise Testing Identifies Adults With Congenital Heart Disease at Increased Mortality Risk in the Medium Term

Study Questions:

What is the prognostic value of cardiopulmonary exercise testing (CPX) for mid-term survival in adults with congenital heart disease (ACHD)?

Methods:

A retrospective review was performed at a single center over a 1-year period. Exercise parameters included peak oxygen consumption (peak VO2), ventilation per unit of carbon dioxide production (VE/VCO2 slope), and heart rate reserve (HRR). HRR was calculated as the difference between peak and resting heart rates.

Results:

The study enrolled 1,375 consecutive ACHD patients who underwent exercise testing. During the median follow-up period of 5.8 years, 117 patients died. Lower peak VO2 and HRR were associated with increased risk of death. A higher VE/VCO2 slope was related to increased risk of death in acyanotic, but not in cyanotic patients. After adjusting for clinical parameters including the use of negative chronotropic agents, age, and presence of cyanosis, the combination of peak VO2 and HRR provided the greatest predictive value.

Conclusions:

CPX provides strong prognostic information on patients with ACHD and is dependent on the presence of cyanosis, the use of rate-lowering medications, and the achieved level of exercise.

Perspective:

Exercise testing is commonly performed in ACHD clinics, and CPX parameters for common congenital heart lesions have been well reported in the literature. This study addresses the prognostic value of exercise testing in ACHD patients. The study did include patients as young as 14 years, while most North American ACHD clinics would include patients 18 years and above. It seems unlikely that this would have a major impact on the ability to generalize these results. One interesting feature of the study is the overall 5-year mortality rates for individual lesions, as reported in the study. The predicted 5-year mortality for repaired tetralogy of Fallot, Fontan physiology, and Eisenmenger syndrome were 2.9%, 16.3%, and 21.1%, respectively. This study reinforces the utility of exercise testing in ACHD patients, and should be incorporated into future appropriateness criteria guidelines.

Clinical Topics: Congenital Heart Disease and Pediatric Cardiology, Congenital Heart Disease, CHD & Pediatrics and Quality Improvement

Keywords: Cyanosis, Tetralogy of Fallot, Risk, Carbon Dioxide, Follow-Up Studies, Heart Rate, Heart Diseases, Prognosis, Eisenmenger Complex, Oxygen Consumption, Respiration, United States, Exercise Test


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