RV stroke work in children with pulmonary arterial hypertension: estimation based on invasive haemodynamic assessment and correlation with outcomes.

BACKGROUND: RV performance is an important determinant of outcomes in children with pulmonary arterial hypertension (PAH). RV stroke work (RVSW), the product of mean pulmonary artery pressure and stroke volume, integrates contractility, afterload and ventricular-vascular coupling. RVSW has not been evaluated in children with PAH. We tested the hypothesis that RVSW would be a predictor of outcomes in children with PAH. METHODS: Patients in the Children's Hospital Colorado PAH database were evaluated retrospectively, and those with idiopathic PAH and those with minor or repaired congenital heart disease were included. Haemodynamic data were obtained by catheterisation and echocardiography, performed within 3 months. RVSW was calculated: mean pulmonary arterial pressure × stroke volume, and indexed to body surface area. Statistics included Kruskal-Wallis, Wilcoxon rank sum, and Spearman correlation. RESULTS: Fifty patients were included. Median age of the cohort was 9.5 (6.0, 15.7) years, with a median indexed pulmonary vascular resistance (PVRi) of 6.5 (3.7, 11.6) WU m(2). RVSW had a significant association with PVRi (r=0.6, p<0.0001), tricuspid annular systolic plane excursion (r=0.55, p=0.0001), and RV fractional area change (r=-0.4, p=0.005). Grouped by WHO class, there was a significant difference in RVSW (p=0.04). Need for atrial septostomy and death were associated with higher RVSW (p=0.04 and p=0.03, respectively). CONCLUSIONS: RVSW can be estimated in children with PAH, and is significantly associated with abnormal WHO class, the need for septostomy, as well as mortality. Indices accounting for RV performance as well as ventricular-vascular coupling may be useful in the prognosis and, hence, management of children with PAH.

Assessment of the relationship between Contegra conduit size and early valvar insufficiency.

BACKGROUND: Contegra bovine jugular vein (BJV) conduit results vary widely, and little attention has been directed at assessment of early conduit insufficiency. Conduit insufficiency is graded subjectively, and criteria vary. Several studies have used branch pulmonary artery flow reversal (BPAFR) to define severe conduit insufficiency. BJV valves are larger than human pulmonary valves of similar diameter. We hypothesize that anatomic differences between BJV and human pulmonary valves limit the use of BPAFR in the evaluation of BJV competence. Our purposes were to (1) assess the prevalence of early and 6-month BJV conduit insufficiency in our patients, (2) determine if conduit size affects BJV competence, and (3) determine if BPAFR is a specific discriminator of severe conduit insufficiency. METHODS: We reviewed 135 BJV conduits. One cardiologist blinded to original reports reviewed postoperative and 6-month echocardiograms. Conduits were grouped by size: group 1, 12 to 14 mm (n=51), and group 2, 16 to 22 mm (n=84). Moderate or greater insufficiency was considered clinically significant. RESULTS: Early conduit insufficiency was common in group 1 (37%) and rare in group 2 (5%, p<0.0001). After excluding conduits with significant insufficiency, BPAFR occurred in 18% (group 1, 27%; group 2, 13%; p=0.02). At follow-up, insufficiency worsened in group 1 but was stable in group 2. CONCLUSIONS: Early conduit insufficiency is common and worsens with follow-up in small BJVs. Conduit insufficiency is limited in larger sizes and remains stable. BJV exhibits BPAFR commonly in the absence of significant conduit insufficiency. BPAFR should not be used as a primary criterion for grading insufficiency in BJV conduits.