Quantification of ventricular stress in univentricular hearts during early childhood using age-independent zlog-NT-proBNP

BACKGROUND

Children with univentricular hearts (UVH) undergo up to three palliative surgical procedures to achieve complete circulatory separation (Fontan circulation). As a marker of cardiac wall stress, NT-proBNP is a promising tool to assess systemic ventricular load in these patients. However, different reference intervals (RI) apply to each stage, as NT-proBNP is highly age-dependent.

METHODS

Children undergoing systemic-to-pulmonary (SP) shunt placement (stage 1), bidirectional cavopulmonary shunt (BCPS, stage 2) or total cavopulmonary connection (TCPC, stage 3) between 2011 and 2021 with NT-proBNP measurement within 7 days before surgery were included. Furthermore, outpatients after TCPC with NT-proBNP measurement were enrolled. Biomarker levels were evaluated using its age-adjusted z-score ("zlog-NT-proBNP"; age-independent RI, -1.96 to +1.96), allowing comparison between different stages and revealing changes in systemic ventricular load independent of the marked physiological decline in RI with age.

RESULTS

Overall, 289 children (227 before, 62 after TCPC) met the eligibility criteria. Median time between blood sampling and surgery (SP shunt/BCPS/TCPC) was 2 [1-3] days and 3.2 [2.0-4.5] years after TCPC. Age-adjusted zlog-NT-proBNP levels were 3.47 [2.79-3.93] in children with native UVH (before SP shunt), 3.10 [1.89-3.58] at stage 1 (before BCPS), 1.08 [0.51-1.88] at stage 2 (before TCPC), and 1.09 [0.72-1.75] at stage 3 (after TCPC/Fontan completion). Consequently, BCPS revealed the strongest decrease (median - 2.02 logarithmized standard deviations, p < 0.001).

CONCLUSIONS

In children with UVH undergoing staged Fontan palliation, zlog-NT-proBNP is a highly promising tool for course assessment of systemic ventricular load, independent of the age-related decline in physiological NT-proBNP concentration.

Development of Weight and Height Age z-Score after Total Cavopulmonary Connection

OBJECTIVE

 We aimed to analyze somatic growth of patients after total cavopulmonary connection (TCPC) as well as to identify factors influencing postoperative catch-up growth.

METHODS

 A total of 309 patients undergoing TCPC at 4 years old or less between 1994 and 2021 were included. Weight for age z-score (WAZ) and height for age-z-score (HAZ) at TCPC and at postoperative time between 1 and 3 years were calculated. Factors influencing somatic growth were analyzed.

RESULTS

 Most frequent diagnosis and initial palliation were hypoplastic left heart syndrome (HLHS) (34%) and the Norwood procedure (51%), respectively. Median age and weight at TCPC were 2.0 (IQR: 1.7-2.5) years and 11.3 (10.5-12.7) kg, respectively. Median 519 days after TCPC, a significant increase in WAZ (-0.4 to -0.2, p < 0.001) was observed, but not in HAZ (-0.6 to -0.6, p = 0.38). Older age at TCPC (p < 0.001, odds ratio [OR]: 2.6) and HLHS (p = 0.007, OR: 2.2) were risks for low WAZ after TCPC. Older age at TCPC (p = 0.009, OR: 1.9) and previous Norwood procedure (p = 0.021, OR: 2.0) were risks for low HAZ after TCPC. Previous bidirectional cavopulmonary shunt (BCPS) was a protective factor for both WAZ (p = 0.012, OR: 0.06) and HAZ (p = 0.028, OR: 0.30) at TCPC.

CONCLUSION

 In patients undergoing TCPC at the age of 4 years or less, a significant catch-up growth was observed in WAZ after TCPC, but not in HAZ. Previous BCPS resulted to be a protective factor for a better somatic development at TCPC. HLHSs undergoing Norwood were considered as risks for somatic development after TCPC.