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-Angiotension-Aldosteron System(RAAS) inhibitors and β-blockers with long-term survival. METHODS AND RESULTS We identified 150 TGA-AtrSO patients(median age 30 years[IQR 25-35], 63% male) included in the CONCOR registry from five tertiary medical centers with subsequent linkage to the Dutch Dispensed Drug Register for the years 2006-2014. Use of RAAS inhibitors, β-blockers, and diuretics increased with age, from respectively 21%[95%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 β-blockers in symptomatic patients(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 β-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 β-blockers in symptomatic patients only. These findings can direct future guidelines, supporting use of RAAS inhibitors and β-blockers in symptomatic, but not asymptomatic patients.