These results and inferences must be viewed cautiously. The cohort studied by Frigiola et al14 comprises only patients with “simple” TOF, that is, those with patent RVOT. Patients with more complex forms such as those with pulmonary atresia and other anatomic variants or associated anomalies were excluded. Therefore, the burden of residual disease and excess mortality reported in their article depicts a best-case scenario, with higher rates of morbidity and mortality expected when high-risk groups are included. Furthermore, among the small random sample of “ideal” TOF patients who were invited for further evaluation, we do not know how many declined participation and whether those who underwent further testing represent the broader cohort of patients who are asymptomatic and did not require cardiac interventions during follow-up. Moreover, we do not know whether these patients are at risk for developing late cardiac complications such as atrial flutter/fibrillation, ventricular tachycardia, or ventricular dysfunction. It is therefore prudent to continue to view repaired TOF as a lifelong disease that requires careful monitoring. Despite these limitations, the study by Frigiola et al14 provides useful information that highlights both ends of the disease spectrum and stimulates the ongoing discussion on timing and indications for PVR. Their findings confirm that a substantial proportion of adolescents and adults with repaired TOF receive PVR and that the frequency of the procedure increases as patient age rises. Notably, even among the small selected group of patients free of PVR, fewer than one third fulfilled the authors’ criteria for good outcome. This raises the question of whether the remaining patients should have undergone earlier PVR and whether such a management strategy would have resulted in better outcomes. The authors correctly note the lack of consensus regarding optimal timing of PVR and comment that their study does not directly address this question; however, coupled with the observation that PVR is the most frequently performed surgical procedure in adults with congenital heart disease in the United Kingdom, their findings underscore the importance of fine-tuning the indications for PVR in this population. Despite the lack of consensus and the many persisting gaps in knowledge, the question of when to recommend PVR is a dilemma that confronts clinicians with increasing frequency. The Table provides a set of possible recommendations based on the author’s interpretation of the current literature. These recommendations, which do not represent the opinion of any institution or professional society, are based on the available evidence gleaned from studies that analyzed pre-PVR markers of post-PVR normalization of ventricular size or function. Little or no information is currently available to inform us about ventricular performance late after PVR, pre-PVR risk factors for post-PVR arrhythmias, exercise intolerance, or mortality. Furthermore, we have no information on how to apply pre-PVR risk factors to different anatomic or surgical phenotypes. We also do not know whether therapeutic interventions designed to modify these risk factors will, in fact, translate into a clinical benefit. With these limitations in mind, the guidelines outlined in the Table are meant to serve as a starting point for a discussion within our field and as a stimulus for future investigations designed to shed new light on areas where data are lacking. 15–20

The study by Frigiola et al14 raises intriguing questions about our ability to identify patients with good outcomes late after TOF repair and, conversely, those at risk of poor outcomes. Simultaneously, though, the authors …