Pediatric Cardiology

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: Introduction 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.   Results 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.   Figure 1   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.   Discussion 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.   Conclusions 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.   

Impact of Major Residual Lesions on Outcomes After Surgery for Congenital Heart Disease. Nathan M, Levine JC, Van Rompay MI, Lambert LM, Trachtenberg FL, Colan SD, Adachi I, Anderson BR, Bacha EA, Eckhauser A, Gaynor JW, Graham EM, Goot B, Jacobs JP, John R, Kaltman JR, Kanter KR, Mery CM, LuAnn Minich L, Ohye R, Overman D, Pizarro C, Raghuveer G, Schamberger MS, Schwartz SM, Narasimhan SL, Taylor MD, Wang K, Newburger JW; Pediatric Heart Network Investigators.J Am Coll Cardiol. 2021 May 18;77(19):2382-2394. doi: 10.1016/j.jacc.2021.03.304.PMID: 33985683   Take Home Points: Major residual lesions after CHD repair impact in-hospital outcomes for both mortality and length of stay> Future studies looking at greater granularity within the Residual Lesion Score (RLS) should be undertaken to help determine which lesions should be addressed prior to initial discharge Commentary from Dr. Jared Hershenson (Greater Washington DC), section editor of Pediatric and Fetal Cardiology Journal Watch: Of the many factors that affect outcomes after surgical repair of congenital heart defects, residual lesions would logically be significant for in-hospital morbidity, length of stay (ICU and total), as well as mortality. Past studies have looked at the Technical Performance Score TPS), but the generalizability is poor due to single center retrospectively collected data. This multicenter group met to refine the TPS using a modified RAND-Delphi technique and renamed it the Residual Lesion Score (RLS). This was prospectively collected data based on the discharge echo or need for unplanned reintervention during index hospitalization. They characterized each procedure by multiple subcomponents as measures of completeness of repair and then voted on whether this would be part of the RLS.   Infants age < 1 year with one of five common CHD of increasing complexity were studied, tetralogy of Fallot (TOF), complete AVSD, arterial switch (ASO) with/without VSD, coarctation/interrupted arch, and Norwood. No or trivial lesions were classified as RLS1, minor residual lesions RLS2, and major residual lesions or unplanned reinterventions RLS3. They also used RSL4 for patients with incomplete echocardiograms and RLS5 for those that did not have any pre-discharge echo. Primary outcome measures included number of days alive and out of hospital within 30 days of surgery (60 days for Norwood). Multiple secondary outcomes mostly related to morbidity were also assessed.   1149 patients were enrolled. Table 2 (central illustration) shows the numbers and percentages of patients with residual lesions. RLS3 was associated with worse primary outcomes for all types of surgeries (Figure 1A). There was no difference between RLS1 and RLS2. For secondary outcomes, RSL3 was associated with longer stay for all operations in bivariate and multivariate analysis. Notably, and likely obviously, when RLS3 was assigned for an unplanned reintervention (vs. discharge echo finding), outcomes were worse. This was most common in the Norwood group (usually shunt or arch intervention). For the other secondary outcomes, this varied by operation. RSL3 was significant for all outcomes after the Norwood. Other operations have a few significant findings for RSL3 and other lacking statistical significance. There was no consistent effect of RLS2 vs. RLS1 on any outcomes. When trying to determine the impact of RLS3 vs. other patient or pre-operative variables, the authors found a 20% R^2. In TOF, the R^2 was only 5%.   Overall, RLS1 and RLS2 had limited impact, but RLS3 significantly impacted morbidity and mortality even after controlling for other variables. However, the authors do note that no model explained more than 50% of the variance in outcomes, suggesting other as yet unidentified factors having an important impact. There are a few other important limitations to this study as identified by the authors and mentioned in an accompanying editorial. First, this analysis was only for children ages < 1 year. Also, since RLS was derived by pre-discharge echo, and not by earlier inpatient echo or post-operative TEE, how to intervene based on this data to prevent the poor outcomes in RLS3 is not clear. There may be multiple levels within RLS3 that may better predict the impact of inadequate repair on the outcomes, e.g. perhaps some lesions should be addressed and others left alone. Finally, there are some residual lesions that cannot be repaired or should not be repaired due to risk, and RLS does not discriminate whether an attempted repair did occur or when the care team decides lesions should not be repaired. This study was an important step in hopefully helping clinicians make decisions that can improve morbidity and mortality when residual lesions are present. Since the ultimate goal is to improve outcomes, further studies using the RLS should be done, with a goal of identifying and acting upon those truly modifiable lesions during the index hospitalization.