Introduction:
After anatomic repair (AR) of congenitally corrected transposition of the great arteries (ccTGA), the left ventricle (LV) is re-established as the systemic ventricle. As such, LV dysfunction is an important factor in long-term patient morbidity. While predictors exist for successful AR, little is known regarding measures of LV function before and after AR, and no known predictors exist of worsening global longitudinal strain (GLS).
Methods:
All patients with ccTGA who survived to discharge after AR at a single institution from 2000-2018 were included. Pre-operative and discharge echocardiograms were reviewed and GLS analysis was performed. LV sphericity index was measured to determine the degree of ventricular septal shift; a lower index denotes more septal bowing into the LV. Logistic regression was used to identify factors associated with worsened GLS after AR.
Results:
Of 91 survivors (65% male), 51 underwent Senning/arterial switch (ASO) and 40 had Senning/Rastelli. Mean LV ejection fraction (EF) decreased from 66% to 61% after AR (p = 0.0003) with 26% having LVEF less than or equal to 55% (increased from 4% pre-op, p = 0.0003). Mean LV GLS was normal pre-op (-20.0% ± SD 4.1%) but worsened following AR (-16.5% ± 4.6%; p <.0001); abnormal LV GLS (> -18%) increased to 62% (vs 32% pre-op, p <.0001). More patients undergoing Senning/ASO (78%) had abnormal LV GLS at discharge compared to those with a Senning/Rastelli (22%) (odds ratio [OR] 9.3, p <.0001). Abnormal pre-op GLS (OR 5.8, p = 0.002) and lower LV sphericity index (OR 1.05, p = 0.01) were also significantly associated with worsening GLS at discharge. In multivariable analysis, all three remained independently associated with worsened LV GLS. Age at AR, ventricular looping, LV posterior wall thickness, and reintervention prior to discharge were not associated with changed LV GLS at discharge.
Conclusions:
Following AR of ccTGA, LVEF decreases but remains in the normal range, while LV GLS detects abnormalities. Risk factors for worsening GLS include abnormal pre-op LV GLS, lower LV sphericity index, and a Senning/ASO repair. Lower LV sphericity index, or more septal shift into the LV, may represent a “less trained” LV, highlighting the need for careful patient selection for AR.
Late left ventricular dysfunction after anatomic repair of congenitally corrected transposition of the great arteries