Total vascular resistance increases during volume-unloading in asymptomatic single ventricle patients.

OBJECTIVE: While the surgical stages of single ventricle (SV) palliation serve to separate pulmonary venous and systemic venous return, and to volume-unload the SV, staged palliation also results in transition from parallel to series circulation, increasing total vascular resistance. How this transition affects pressure loading of the SV is as yet unreported. METHODS: We performed a retrospective chart review of Stage I, II, and III cardiac catheterization (CC) and echocardiographic data from 2001-2017 in all SV pts, with focus on systemic, pulmonary, and total vascular resistance (SVR, PVR, TVR respectively). Longitudinal analyses were performed with log-transformed variables. Effects of SVR-lowering medications were analyzed using Wilcoxon rank-sum testing. RESULTS: There were 372 total patients who underwent CC at a Stage I (median age of 4.4 months, n=310), Stage II (median age 2.7 years, n = 244), and Stage III (median age 7.3 years, n = 113). Total volume loading decreases with progression to Stage III (P< 0.001). While PVR gradually increases from Stage II to Stage III, and SVR increases from Stage I to Stage III, TVR dramatically increases with progress towards series circulation. TVR was not affected by use of systemic vasodilator therapy. TVR, PVR, SVR, and CI did not correlate with indices of SV function at Stage III. CONCLUSIONS: TVR steadily increases with an increasing contribution from SVR over progressive stages. TVR was not affected by systemic vasodilator agents. TVR did not correlate with echo-based indices of SV function. Further studies are needed to see if modulating TVR can improve exercise tolerance and outcomes.

Clinicians' Adherence to Guidelines on Evaluation of Hypertension in Children and Adolescents.

BACKGROUND: Hypertension is increasingly prevalent among children. We sought to review provider adherence to the National High Blood Pressure Education Program (NHBPEP) recommendations at a single academic medical center. METHODS: We identified children 3-18 years of age with hypertension based on outpatient visit International Classification of Diseases, Ninth Edition, Clinical Modification codes from 2006 to 2012. We calculated the odds of individual tests administration for ten recommended tests, adjusting for demographic characteristics. RESULTS: We identified 3,588 (1.7%) of 216,855 children diagnosed with hypertension at a median age of 14 years (25th and 75th percentile 10 and 16, respectively). No child received all ten recommended tests. The median number of tests administered was 2 (1, 4) but varied significantly by race and age. Urine drug screen (<1%) and renin levels (1%) were the least common, whereas serum creatinine (49%) and echocardiogram (40%) were the most common tests. Male children were more likely to receive an echocardiogram (odds ratio 1.43; 95% confidence interval: 1.24-1.64), and black children and those ≥11 years old were less likely to have their serum creatinine checked. Adherence to the guidelines did not improve over time (P = .24). CONCLUSION: Children evaluated for hypertension in the outpatient setting infrequently receive the diagnostic tests recommended in the NHBPEP's report. Test administration frequency varies by patient demographics but has not improved significantly over time.