Effects of transcatheter pulmonary valve replacement on the hemodynamic and ventricular response to exercise in patients with obstructed right ventricle-to-pulmonary artery conduits.
OBJECTIVE
This study sought to investigate the effects of exercise on the right ventricle in patients with an obstructed right ventricular outflow tract (RVOT) conduit before and after transcatheter pulmonary valve replacement (TPVR).


BACKGROUND
Conventionally, assessment of the right ventricle in congenital heart disease patients with dysfunctional RVOT conduits is performed at rest. However, this does not reflect dynamic exercise changes.


METHODS
Exercise stress echocardiography (ESE) before and 6 months after TPVR was performed. ESE protocol included measurement of rest and immediate post-exercise RVOT maximal instantaneous gradients (MIGs), right ventricular (RV) systolic pressure, 2-dimensional fractional area change, and global longitudinal strain (GLS).


RESULTS
Twenty patients with RVOT conduit obstruction (median age, 18 years), the majority (n = 14) with tetralogy of Fallot, completed the study. Pre-TPVR, the median resting MIG across the RVOT was 53 mm Hg (23 to 95 mm Hg) and increased to 93 mm Hg (49 to 156 mm Hg; p < 0.001) with exercise. After TPVR, the median MIG at rest was 26 mm Hg (6 to 41 mm Hg, and after exercise, it was 45 mm Hg (9 to 102 mm Hg), both significantly lower than before TPVR (p ≤ 0.001), but there was still a substantial increase in gradient with exercise in many patients. The RV fractional area change, RV GLS, and left ventricular GLS, both at rest and after exercise, were significantly greater after TPVR than before. A greater pre-TPVR exercise-related increase in RV function was associated with improvement in peak Vo2 after TPVR (p = 0.01).


CONCLUSIONS
In patients with obstructed RVOT conduits, TPVR resulted in significant improvement in conduit stenosis and RV function at both rest and at peak exercise and in exercise cardiopulmonary function. The ability to augment RV function at peak exercise before TPVR was associated with improved exercise capacity 6 months after TPVR.
Department of Cardiology, Boston Children's Hospital, Department of Pediatrics, Harvard Medical School, Boston, Massachusetts. Electronic address: babar.hasan@aku.edu.
Babar S
BS
Hasan
Department of Cardiology, Boston Children's Hospital, Department of Pediatrics, Harvard Medical School, Boston, Massachusetts.
Fatima I
FI
Lunze
Department of Cardiology, Boston Children's Hospital, Department of Pediatrics, Harvard Medical School, Boston, Massachusetts.
Ming Hui
MH
Chen
Department of Cardiology, Boston Children's Hospital, Department of Pediatrics, Harvard Medical School, Boston, Massachusetts.
David W
DW
Brown
Department of Cardiology, Boston Children's Hospital, Department of Pediatrics, Harvard Medical School, Boston, Massachusetts.
Matthew J
MJ
Boudreau
Department of Cardiology, Boston Children's Hospital, Department of Pediatrics, Harvard Medical School, Boston, Massachusetts.
Jonathan
J
Rhodes
Department of Cardiology, Boston Children's Hospital, Department of Pediatrics, Harvard Medical School, Boston, Massachusetts.
Doff B
DB
McElhinney
D000293:Adolescent; D000328:Adult; D006328:Cardiac Catheterization; D006348:Cardiac Surgical Procedures / Q000009:adverse effects*; D002648:Child; D025401:Echocardiography, Stress; D017079:Exercise Tolerance; D006330:Heart Defects, Congenital / Q000175:diagnosis / Q000503:physiopathology / Q000601:surgery*; D019918:Heart Valve Prosthesis Implantation / Q000379:methods*; D006439:Hemodynamics; D006801:Humans; D008297:Male; D009200:Myocardial Contraction; D011446:Prospective Studies; D011664:Pulmonary Valve / Q000503:physiopathology / Q000601:surgery*; D020127:Recovery of Function; D013997:Time Factors; D016896:Treatment Outcome; D016277:Ventricular Function, Left; D016278:Ventricular Function, Right; D014694:Ventricular Outflow Obstruction / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology / Q000601:surgery*; D017725:Ventricular Pressure; D055815:Young Adult
congenital heart defects; exercise echocardiography; percutaneous valve replacement