The Impact of Pulmonary Insufficiency on the Right Ventricle: A Comparison of Isolated Valvar Pulmonary Stenosis and Tetralogy of Fallot

Abstract

Introduction Pulmonary insufficiency (PI) is associated with right ventricular (RV) dilation, dysfunction and exercise intolerance in patients with tetralogy of Fallot (TOF). We sought to compare RV function and exercise performance in patients with valvar pulmonary stenosis (VPS) following pulmonary balloon valvuloplasty to those with repaired TOF with similar degrees of PI. Methods We performed a cross-sectional study of patients with VPS and TOF. Cardiac magnetic resonance (CMR) and exercise stress test (EST) were performed. Subjects were matched by time from initial procedure and severity of PI using propensity scores. Results After matching, there were 16 patients with VPS and 16 with TOF for comparison, with similar demographics. Time from initial procedure was 14 years (12; 16), p= 0.92, and pulmonary regurgitant fraction was 19 % (6; 31), p= 0.94, Patients with TOF had lower ejection fraction [58 % (53; 66) vs. 65 % [60; 69], p= 0.04] and more RV hypertrophy [69 g/m2 [52; 86] vs. 44 g/m2 [32; 66], p=0.04] compared to those with VPS. Aerobic capacity was worse in patients with TOF [68 ± 19% mVO2 (56; 84) vs. 82 ± 9.2 % (74; 89) in VPS, p=0.01], with a trend for less habitual physical activity [0.9 (0; 12) vs. 8 hours/ week (4; 12), p= 0.056], respectively. Conclusions With similar degrees of PI, patients with TOF demonstrate worse RV function and aerobic capacity as compared to patients with just VPS. Habitual exercise may in part explain differences in exercise performance and should be further explored.

Quality of Life is Diminished in Patients with Tetralogy of Fallot with Mild Residual Disease: A Comparison of Tetralogy of Fallot and Isolated Valvar Pulmonary Stenosis

“…We conducted a single-center cross-sectional study of subjects with VPS ages 8–18 years at The Children’s Hospital of Philadelphia (CHOP) from June 2009 to February 2010 as previously described [19]. This study was approved by the Institutional Review Board for the Protection of Human Subjects at CHOP (IRB #6372).…”

“…Subjects with VPS and TOF were matched by duration and severity of PI [years from initial procedure and pulmonary regurgitant fraction (RF) on CMR, respectively] using propensity score matching. This resulted in a group of TOF subjects with mild disease, given that the VPS group had on average mild residual PI after balloon dilation [19, 22]. In this study, the health status of the TOF group and VPS group was compared with healthy control population using published normative data available for the CHQ-PF50 [23, 24].…”

“…CMR studies were performed using a standard imaging protocol and read by an experienced physician blinded to the patients’ clinical information, as previously described [19]. PI was measured as pulmonary RF and considered mild if it is <20%, moderate if 21–40%, and severe if greater than 40%.…”

“…Patients completed an exercise protocol as previously described [19]. The percent of predicted maximum V O 2 (%mV O 2 ) was calculated for each patient, according to normative values for age, gender, and body size.…”

“…The percent of predicted maximum V O 2 (%mV O 2 ) was calculated for each patient, according to normative values for age, gender, and body size. Percent-predicted mV O 2 was considered abnormal if less than 85% predicted [19]. Oxygen pulse was calculated as the mV O 2 divided by the peak heart rate and indexed for body surface area (ml/O 2 /beat/m 2 ) and used as a surrogate of stroke volume.…”