Hemodynamic Impact and Prognostic Relevance of Right Ventricular Pressure Load in Patients after Repair of the Tetralogy of Fallot

Objectives: As a consequence of surgical repair of the tetralogy of Fallot (TOF) pulmonary regurgitation (PR) frequently results as the predominant residual lesion causing progressive RV enlargement, functional impairment, and probably sudden cardiac death (SCD). In addition, some degree of RV pressure load may coexist which has recently been linked with adverse outcome, although favorable effects on RV remodeling have also been reported. The aim of our study was to assess the hemodynamic impact and prognostic relevance of RV pressure load in this population.

Methods: In a prospective multicenter study, 337 TOF patients (mean age, 17.8 ± 8.0 years) with a complete CMR dataset, CPET study and echocardiographic RVOT gradient were included. Feature tracking analysis was performed to quantify systolic and diastolic strain values. The combined end-point consisted of ventricular tachycardia, aborted SCD and cardiac death. Need for intercurrent pulmonary valve replacement (PVR) was also assessed.

Result: RVOT-gradient (median 16 [2–83] mm Hg) was significantly associated with smaller RV volumes (r = &−0.16, p = 0.004) and less PR (r = &−0.12, p = 0.026) but lower RV (r = &−0.23, p = 0.0004) and LV longitudinal systolic strain (r = &−0.15, p = 0.016) and lower early diastolic strain rate (RV: r = &−0.17, p = 0.01, LV: r = &−0.22, p = 0.0006). No relationships were found between RVOT-gradient and RVEF, RV mass, RV mass-to-volume ratio and peak VO₂. In 301 of the 337 patients, longitudinal follow-up data was available. During a median follow-up of 10.1 (0.1–12.9) years the primary endpoint was reached in 16 patients (cardiac death n = 5, sustained VT n = 2, nonsustained VT n = 9) and in 122 patients PVR was performed. Using Cox’s regression analysis a higher initial RVOT-gradient was significantly associated with the combined outcome (HR = 1.03, CI: 1.00–1.06, p = 0.026) and the need for PVR (HR = 1.02, CI: 1.01–1.03, p = 0.001). An initial RVOT-gradient &≥25 mm Hg was predictive for cardiovascular events (HR = 3.52, CI: 1.30–9.57, p = 0.0014).

Conclusion: Although a higher initial RVOT-gradient was associated with less PR and smaller RV volumes, a negative effect on systolic and diastolic biventricular longitudinal function was present. A mildly increased pressure gradient was associated with adverse outcome which may have implications for both the initial surgical strategy and the indication for PVR in repaired TOF patients.