Medication in adults after atrial switch for transposition of the great arteries: clinical practice and recommendations

Aims Heart failure is the main threat to long-term health in adults with transposition of the great arteries (TGA) corrected by an atrial switch operation (AtrSO). Current guidelines refrain from recommending heart failure medication in TGA-AtrSO, as there is insufficient data to support the hypothesis that it is beneficial. Medication is therefore prescribed based on personal judgements. We aimed to evaluate medication use in TGA-AtrSO patients and examine the association of use of renin-angiotensin-aldosterone system (RAAS) inhibitors and beta-blockers with long-term survival. Methods and results We identified 150 TGA-AtrSO patients [median age 30 years (interquartile range 25-35), 63% male] included in the CONCOR registry from five tertiary medical centres with subsequent linkage to the Dutch Dispensed Drug Register for the years 2006-2014. Use of RAAS inhibitors, beta-blockers, and diuretics increased with age, from, respectively, 21% [95% confidence interval (CI) 14-40], 12% (95% CI 7-21), and 3% (95% CI 2-7) at age 25, to 49% (95% CI 38-60), 51% (95% CI 38-63), and 41% (95% CI 29-54) at age 45. Time-varying Cox marginal structural models that adjusted for confounding medication showed a lower mortality risk with use of RAAS inhibitors and b-blockers in symptomatic patients [hazard ratio (HR) = 0.13 (95% CI 0.03-0.73); P = 0.020 and HR = 0.12 (95% CI 0.02-0.17); P = 0.019, respectively]. However, in the overall cohort, no benefit of RAAS inhibitors and b-blockers was seen [HR = 0.93 (95% CI 0.24-3.63); P = 0.92 and HR = 0.98 (0.23-4.17); P = 0.98, respectively]. Conclusion The use of heart failure medication is high in TGA-AtrSO patients, although evidence of its benefit is limited. This study showed lower risk of mortality with use of RAAS inhibitors and beta-blockers in symptomatic patients only. These findings can direct future guidelines, supporting use of RAAS inhibitors and b-blockers in symptomatic, but not asymptomatic patients.