Predicting functional capacity in patients with a systemic right ventricle: subjective patient self-assessment is better than B-type natriuretic peptide levels and right ventricular systolic function.

BACKGROUND: Many adults with transposition of the great arteries have an anatomic right ventricle functioning as the systemic ventricle and are known to develop congestive heart failure, premature cardiac death, and need for cardiac transplantation. Predictors of poor clinical outcome and functional status in patients with left ventricular failure do not always apply to these patients. We aimed to identify predictors of poor functional status in those patients with a systemic right ventricle.

METHODS: We performed a prospective study of 51 adults with transposition of the great arteries and systemic right ventricles. Demographic, clinical, laboratory, and imaging data were collected, and patients completed a Minnesota Living with Heart Failure Questionnaire (MLHFQ). Comparisons were made between those patients with d-type transposition of the great arteries (dTGA) who have undergone prior atrial switch and those with congenitally corrected transposition (ccTGA). A correlation analysis was performed to identify predictors of poor functional status, as determined by a 6-minute walk distance test.

RESULTS: Median age was 30 years (range 19-65). Median B-type natriuretic peptide was 48 pg/mL (range 16-406). There were 27 patients (53%) with moderate-severe right ventricular dysfunction and 10 (20%) with moderate-severe tricuspid valve regurgitation. The median MLHFQ score was 9 (range 0-78) and 6-minute walk test was 510 m (range 231-703). Forty-one patients had a diagnosis of dTGA atrial switch and 11 patients had ccTGA. Patients with ccTGA were significantly older (40 vs. 28 years, P =.004) and had more tricuspid valve regurgitation (P =.02). Despite this, their MLHFQ scores were significantly lower (2.5 vs. 17, P =.04) and they walked further (635 vs. 504 m, P =.02). Predictors of a short 6-minute walk distance included short stature (P =.009) and dTGA (P =.002). The patient's self-assessment of poor health, as measured by an increased New York Heart Association class (P =.003) and a decreased MLHFQ score (P >.0001) also correlated. B-type natriuretic peptide levels, right ventricular dysfunction, severity of tricuspid valve regurgitation, need for pacemaker, and clinical signs of heart failure did not correlate with exercise tolerance.

CONCLUSIONS: Traditional parameters used to predict outcomes in patients with left ventricular failure are not predictive in patients with a systemic right ventricle. Instead, patient's self-assessment of functional status did correlate with objective functional status.