Indications for Pulmonary Valve Replacement in Tetralogy of Fallot
What is the association between preoperative right ventricular (RV) volume thresholds and mid-to-late RV cardiac magnetic resonance (CMR) imaging and clinical events in adults with tetralogy of Fallot (TOF) undergoing pulmonary valve replacement (PVR)?
A retrospective, multicenter review was performed of patients >12 years of age undergoing PVR at three academic centers.
During the study period, 157 TOF patients underwent PVR, of which 65 underwent pre- and postoperative CMR imaging. Mean age at PVR was 29 ± 8 years. RV normalization, defined as RV ejection fraction (EF) >48% and RV end-diastolic volume (EDV) <108 ml/m2, occurred in 14 of 65 patients (22%). “Intermediate” mid-to-late hemodynamic outcomes, defined as RVEF 45-48% and RVEDV 108-120 ml/m2, occurred in 34 of 65 (52%) patients. “Suboptimal” outcomes (RVEF <45% and RVEDV >120 ml/m2), occurred in 17 of 65 (26%) patients. Preoperative RV end-systolic volume (ESV) <80 ml/m2 was associated with the most favorable postoperative RV parameters by CMR. In terms of clinical outcomes, adverse events (defined as death, sustained ventricular tachycardia, or heart failure) occurred in 18 of 106 (17%) patients with preoperative CMR available. Patients with RVESV >95 ml/m2 were at increased risk for events (hazard ratio, 2.89; 95% confidence interval, 1.03-8.11).
In patients with TOF undergoing PVR, normalization of RV parameters was most likely to occur when preoperative RVESV was <80 ml/m2. Patients with preoperative RVESV of >95 ml/m2 were at increased risk for suboptimal postoperative CMR imaging parameters as well as adverse clinical events.
Controversy remains as to the optimal indications for PVR in patients with TOF. It has been previously reported that ventricles which have dilated to >160 ml/m2 will not remodel to normal size (<108 ml/m2) after PVR. This study importantly includes clinical outcomes in addition to postoperative CMR parameters. This study showed ESV measures to be more useful than EDV measures in predicting postoperative CMR imaging values and clinical outcomes. The study supports intervention for a dilating RV prior to reaching an ESV of 80-95 ml/m2.
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