Improved Outcomes After Pulmonary Valve Replacement in Repaired Tetralogy of Fallot.
Geva T, Sleeper LA, Lee JH, Lu M, Sompolinsky T, Babu-Narayan SV, Wald RM, Mulder BJM, Valente AM.J Am Coll Cardiol. 2023 May 30;81(21):2075-2085. doi: 10.1016/j.jacc.2023.02.052.PMID: 37225360
Take Home Points:
Pulmonary valve replacement (PVR) in repaired Tetralogy of Fallot (TOF) has uncertain impact on major adverse clinical outcomes. Using an International multicenter TOF (INDICATOR) Registry and PVR propensity score, the authors found patients who received PVR had a lower risk of composite endpoint of death or sustained ventricular tachycardia (VT) (death adjusted HR 0.41, 95% CI: 0.21-0.81, p=0.010).
On subgroup analysis, PVR in patients with advanced right ventricular (RV) dilatation was thought to be more beneficial:
- If RVESV index was >80mL/m2, PVR was associated with lower risk (HR: 0.32; 95% CI: 0.16-0.62: p<0.001)
- If RVESV index was ≤80mL/m2 there was no improved outcome (HR:0.86; 95% CI: 0.38-1.92; p= 0.70)
Commentary from Dr Simon MacDonald (London, UK), section editor of ACHD Journal Watch:
Tetralogy of Fallot (TOF) is the commonest cyanotic congenital heart defect. Repair of the ventricular septal defect and removal of right ventricular outflow tract (RVOT) obstruction can leave many with pulmonary regurgitation. In turn this causes RV loading with RV dilatation and dysfunction with subsequent impact on tricuspid valve function, risk of atrial and ventricular arrythmias and impact on left ventricular function. The best timing of PVR in this setting has been unclear, with no randomized control data to guide management.
The authors used a large sample size and analysed data from the INDICATOR (International Multicentre TOF) registry, an observational dataset of patients undergoing cardiovascular magnetic resonance imaging (CMR) at 4 large congenital heart centres (Amsterdam in the Netherlands, Boston Childrens Hospital in the USA, Royal Brompton in the UK and the Toronto Congenital Cardiac Centre in Canada). Patients had to have repaired TOF, CMR after 1st of January 2002 with RV data, BSA ≥1.0m2, and CMR within 3 years of intervention if undergoing PVR. Follow-up was taken from the date of the qualifying CMR.
The composite primary outcome was time to the earliest occurrence of all death, resuscitated arrest, or sustained VT (lasting >30 seconds or cardioverted). The composite secondary outcome was time to earliest occurrence of advanced heart failure (New York Heart Association functional class III or IV), non-sustained VT lasting <30 seconds, or sustained supraventricular tachycardia requiring treatment.
The PVR propensity score included site, age at repair, repair before or after 1980, age at qualifying CMR, RV end diastolic (RVEDV) index, RV end systolic (RVESV) index, RV mass/volume ratio, RV ejection faction, LV ejection fraction and QRS duration. Patients with and without PVR were matched 1:1 according to this propensity score.
Of 1808 potential patients, 1143 met study criteria with 540 (47%) having a PVR (453 or 84% surgical and 87 or 16% percutaneous) with a median of 0.37 years post initial CMR.
82 of 1143 (7%) patients experienced the primary outcome during median follow-up of 8.0 (IQR 3.8-12.7 years). 58 patients died, 18 had sustained VT and 6 were resuscitated post arrest. 524 patients were included in a matched analysis with 42 (8%) primary outcome events. PVR seemed protective in the cohorts with an adjusted HR 0.41 (95% CI: 0.21-0.81; p=0.01)
With regards to secondary composite outcomes there appeared no benefit.
Current ESC and AHA guidelines suggest elective PVR is appropriate with severe RV dilatation (indexed RVESV >80mL/m2 or RVEDV >160mL/m2) and were based on observational studies. The current findings suggest that without severe RV dilatation, PVR may not be beneficial and thus favour the existing thresholds in current guidelines. In terms of limitations, it was an observational cohort study with a limited set of variables and artificial categorisations and will have ignored patients with pacemakers and defibrillators due to the MRI criteria, who already have increased cardiovascular risk. The use of antiarrhythmic medications or electrophysiological interventions in patients was not studied but thought to involve only a small subset of patients. This study perhaps offers the best indication to date about PVR and its benefit for repaired Tetralogy of Fallot patients and its timing.
