Prognostic significance of size and function of the subpulmonary left ventricle in patients with a systemic right ventricle

Abstract

Abstract Funding Acknowledgements Type of funding sources: None. Background Systolic dysfunction of the systemic right ventricle (SRV) is a well-recognized predictor of adverse events in adults with transposition of great arteries (TGA) after atrial switch repair or with congenitally corrected TGA (ccTGA). The prognostic role of subpulmonary left ventricle (LV), however, remains unclear. Purpose To assess the prognostic significance of echocardiographic parameters of subpulmonary LV size and systolic function. Methods All adult patients with the SRV who underwent transthoracic echocardiography in 2010–2018 at a large tertiary referral centre were identified from a digitally recorded echocardiographic database. Biventricular size and function were assessed at the most recent exam. The study endpoint was all-cause mortality and heart or heart-lung transplantation. Results We included 180 patients, 100(55.6%) male, mean age 42.4±12.3 years, of whom 103(57.2%) had undergone Mustard/Senning operations and 77(42.8%) had ccTGA. One half of patients were in NYHA class ≥2 and 113 (63.5%) were receiving heart failure medication(s). During a follow-up period of 4.9[3.8–5.7] years, 28(15.6%) patients died and 4(2.2%) underwent heart or heart-lung transplantation. Univariable predictors of death or transplantation included older age, NYHA class III/IV, history of atrial arrhythmias, presence of pacemaker or cardioverter-defibrillator, high BNP, and echocardiographic markers of both SRV and subpulmonary LV size and function (Figure 1). On multivariable Cox analysis, indexed LV end-systolic diameter (ESDi; HR 2.77 [95%CI 1.35–5.68], p = 0.01), LV fractional area change (FAC; HR 0.7 [95%CI 0.57–0.85], p = 0.002), SRV basal diameter (HR 1.66 [95%CI 1.21–2.29], p = 0.005), and SRV FAC (HR 0.65 [95%CI 0.49–0.87], p = 0.008) remained predictive of mortality or transplantation. On ROC analysis, subpulmonary LV parameters performed better than SRV markers in predicting death or transplantation (Figure 2). Conclusions A raised LV ESDi and reduced LV FAC were strongly associated with mortality and heart or heart-lung transplantation independent of SRV size and function. Accurate echocardiographic assessment of the subpulmonary LV is therefore essential for risk stratification and management of patients with the SRV and should be a part of routine echocardiographic protocols.