The relationship between cardiovascular magnetic resonance imaging measurement of extracellular volume fraction and clinical outcomes in adults with repaired tetralogy of Fallot.

Aims: Our aims were to explore cardiac magnetic resonance quantification of myocardial extracellular volume (ECV) in adults with repaired tetralogy of Fallot (rTOF) when compared with healthy controls and to investigate the association between ECV and major adverse cardiovascular outcomes. Methods and results: We prospectively recruited adults with rTOF (n = 44, 59% male, 32.9 ± 13.6 years) and evaluated right ventricular (RV) and left ventricular (LV) ECV by pre/post-gadolinium T1 measurements (modified Look-Locker inversion recovery technique) on a 1.5-T Siemens scanner compared with the healthy controls (n = 10, 50% male, 31.5 ± 4.4 years). The primary end point was a composite of death, out-of-hospital cardiac arrest, heart failure (HF) requiring admission for escalation of therapy, or haemodynamically significant ventricular tachycardia (VT) (lasting >30 s and/or resulting in invasive therapy). The association between ECV and adverse events was assessed using Cox proportional hazard models [median follow-up 236 days, interquartile range (IQR) 38-342]. RVECV was higher in patients compared with the controls (31.5 ± 5.4% vs. 26.3 ± 2.1%, P = 0.027). The following major adverse events occurred (n = 9, 21%): death (n = 1), out-of-hospital cardiac arrest (n = 1), HF (n = 1), and VT (n = 6). RVECV was higher among those with an adverse event compared to those without (35.0 ± 5.5% vs. 29.6 ± 4.5%, P = 0.014) and was associated with increased risk for adverse events [hazard ratio 1.13, 95% confidence interval (1.01-1.28); P = 0.037]. LVECV was not associated with adverse events (P = 0.667). Conclusion: Increased RVECV is associated with adverse cardiovascular events in adults with rTOF. These results may lead to further studies exploring the potential role for RVECV in risk stratification and targeted therapeutic interventions in this population.

Rationale and design of the Canadian Outcomes Registry Late After Tetralogy of Fallot Repair: the CORRELATE study.

BACKGROUND: Chronic hemodynamically relevant pulmonary regurgitation (PR) resulting in important right ventricular dilation and ventricular dysfunction is commonly seen after tetralogy of Fallot (TOF) repair. Late adverse clinical outcomes, including exercise intolerance, arrhythmias, heart failure and/or death accelerate in the third decade of life and are cause for considerable concern. Timing of pulmonary valve replacement (PVR) to address chronic PR is controversial, particularly in asymptomatic individuals, and effect of PVR on clinical measures has not been determined. METHODS: Canadian Outcomes Registry Late After Tetralogy of Fallot Repair (CORRELATE) is a prospective, multicentre, Canada-wide cohort study. Candidates will be included if they are ≥ 12 years of age, have had surgically repaired TOF resulting in moderate or severe PR, and are able to undergo cardiovascular magnetic resonance imaging. Enrollment of > 1000 individuals from 15 participating centres (Toronto, Montreal, Quebec City, Sherbrooke, Halifax, Calgary, Edmonton, and Vancouver) is anticipated. Clinical data, health-related quality of life metrics, and adverse outcomes will be entered into a web-based database. A central core lab will analyze all cardiovascular magnetic resonance studies (PR severity, right ventricular volumes, and ventricular function). Major adverse outcomes (sustained ventricular tachycardia and cardiovascular cause of death) will be centrally adjudicated. RESULTS: To the best of our knowledge, CORRELATE will be the first prospective pan-Canadian cohort study of congenital heart disease in children and adults. CONCLUSIONS: CORRELATE will uniquely link clinical, imaging, and functional data in those with repaired TOF and important PR, thereby enabling critical evaluation of clinically relevant outcomes in those managed conservatively compared with those referred for PVR.