Longitudinal Assessment of Right Ventricular Function in Hypoplastic Left Heart Syndrome.
Balasubramanian S, Smith SN, Srinivasan P, Tacy TA, Hanley FL, Chen S, Wright GE, Peng LF, Punn R. Pediatr Cardiol. 2021 May 13. doi: 10.1007/s00246-021-02624-y. PMID: 33987707
Take home points:
- Right ventricular (RV) function in the long term affects prognosis in hypoplastic left heart syndrome patients.
- RV fractional area change (FAC) and Tricuspid annular systolic excursion (TAPSE) decreased after all surgical staged palliation procedure.
- Patients with RV FAC ≤ 35% and TAPSE Z-score ≤ -5 had a significantly lower transplant-free survival (p<0.0001).
Commentary from Dr. Manoj Gupta (New York City, NY, USA), chief section editor of Pediatric & Fetal Cardiology Journal Watch:
Failure of RV function remains a significant cause of mortality or transplantation in patients with hypoplastic left heart syndrome (HLHS). In addition to identifying patients who are susceptible to RV failure, understanding the mechanism and timing of decline may allow for closer surveillance and early optimization of medical therapy.
Of the echocardiographic indices, RV FAC showed significant decrease from post-Norwood to all subsequent stages (p < 0.001). In contrast, TAPSE Z-score showed a gradual decrement when pre-Norwood, pre-Glenn and pre-Fontan measures were compared (p < 0.0001).
Interestingly, FAC increased immediately post-Norwood while TAPSE Z-score decreased (Fig. 1). Neo-aortic valve VTI, global longitudinal strain, myocardial performance index and RV sphericity index did not show any trends over the course of the three surgeries.
Fig. 1 Box and Whisker plot comparing echocardiographic measures over the three stages of surgical palliation. Right ventricular FAC showed a statistically significant difference (n=43, p < 0.001). Post-hoc, pairwise comparison revealed differences between post-Norwood and other time points (p < 0.001) as well as between pre- and post-Glenn (p=0.01). TAPSE Z-score showed a statistically significant difference (n=47, p<0.001). Posthoc analysis pre-Norwood, pre-Glenn and pre-Fontan measures were compared (p < 0.0001) and when post-Norwood, post-Glenn and post-Fontan measures were compared (p < 0.0001).
Univariate analysis of serial echocardiographic markers showed post-Norwood RV FAC, TAPSE Z-score, global longitudinal strain, and dichotomized variables RV FAC≤35% and TAPSE Z-score≤-5 to be predictors of transplant-free survival. Using discrete variables, factors independently associated with death or transplant were presence of either RV FAC≤35% or TAPSE Z-score≤-5
RV end-diastolic dimension indexed to body surface area showed a statistically significant decrease following each of the surgeries with the greatest decrease noted following the Glenn operation.
This study showed a decrement in RV function longitudinally as measured by TAPSE and FAC for the whole cohort. In multivariable analysis, post-Norwood lower RV FAC and lower TAPSE Z-score independently predicted death or transplant. The presence of RV FAC≤35% or TAPSE Z-score≤-5 or a combination of the two were associated with a 2-3 fold higher likelihood of death or transplant. TAPSE is a measure of longitudinal shortening of the RV but there are only limited reports on the applicability of TAPSE to single ventricle patients.
Patients undergoing staged palliation for HLHS continue to have significant disease burden. Detection of RV dysfunction measured by FAC≤35% or TAPSE Z-score≤-5 were found to be early predictors of poor outcome of death or transplant. Using these easily obtainable echocardiographic measures may allow early identification of the most vulnerable subset of HLHS patients and alter the intensity of their medical management and longitudinal care.