LAUSR

Patients after atrial switch surgery for transposition of the great arteries (TGA-AtrSO) experience serious clinical events during adulthood, mainly heart failure and arrhythmias, but data on the emerging risks remain scarce. To assess the risk for events during the clinical course in adulthood of TGA-AtrSO patients and provide a novel risk score for event-free survival. We reviewed medical records of TGA-AtrSO patients from five hospitals. Endpoints were all-cause mortality, heart failure (HF), defined as HF hospitalizations, heart transplantation, ventricular assist device implantation, or HF-related death, and symptomatic ventricular arrhythmias (VA). Predictors for event-free survival were examined to construct a prediction model using bootstrapping techniques. We followed 169 TGA-AtrSO patients (60% Mustard, age 28 [IQR 24–36] years) for 13 [IQR 9–16] years, during which 17 (10%) died, 34 (20%) had HF events, and 15 (9%) had VA events. Five-year risk of mortality, first HF event, and first VA increased from 1% each at age 25, to 7% (95% CI 4–10%), 17% (95% CI 10–25%), and 4% (95% CI 2–8%), respectively, at age 50. A prediction model combining age >30, prior VA, age >1 year at repair surgery, QRS duration >120ms, ≥mild LV dysfunction, and severe tricuspid regurgitation discriminated well between patients at low (<5%), medium (5–20%) and high (>20%) 5-year risk (optimism corrected C-statistic=0.84). Observed 5- and 10-year survival in low-risk patients were 100% and 99%, compared to only 45% and 19% in high-risk patients. The clinical course of atrial switch patients increasingly consists of serious clinical events, especially heart failure. A novel risk score stratifying patients as low, medium, and high risk for event-free survival is presented, providing information on absolute individual risks which may support decisions for pharmacological and interventional management. Figure 1. Observed event-free survival of patients with predicted low risk (<5% in 5 years), medium risk (5–20% in 5 years) and high risk (>20% in 5 years). Type of funding source: Foundation. Main funding source(s): Dutch Heart Foundation; Amsterdam University Fund