<p><strong>BACKGROUND/PURPOSE: </strong>Prostaglandin E1 (PGE) has been used to maintain ductus arteriosus patency and unload the suprasystemic right ventricle (RV) in neonates with congenital diaphragmatic hernia (CDH) and severe pulmonary hypertension (PH). Here we evaluate the PH response in neonates with CDH and severe PH treated with PGE.</p>

<p><strong>METHODS: </strong>We performed a retrospective chart review of CDH infants treated at our center between 2011 and 2016. In a subset, PGE was initiated for echocardiographic evidence of severe PH, metabolic acidosis, or hypoxemia. To assess PH response, we evaluated laboratory data, including B-type natriuretic peptide (BNP) and echocardiograms before and after PGE treatment. Categorical and continuous data were analyzed with Fisher's exact tests and Mann-Whitney t-tests, respectively.</p>

<p><strong>RESULTS: </strong>Fifty-seven infants were treated with PGE a mean 17 ± 2 days. BNP levels declined after 1.4 ± 0.2 days of treatment and again after 5.2 ± 0.6 days. After 6 ± 0.8 days of treatment, echocardiographic estimates of severe PH by tricuspid regurgitation jet velocity, ductus arteriosus direction, and ventricular septum position also improved significantly. Treatment was not associated with postductal hypoxemia or systemic hypoperfusion.</p>

<p><strong>CONCLUSIONS: </strong>In patients with CDH and severe PH, PGE is well tolerated and associated with improved BNP and echocardiographic indices of PH, suggesting successful unloading of the RV.</p>

<p><strong>TYPE OF STUDY: </strong>Treatment study.</p>

<p><strong>LEVEL OF EVIDENCE: </strong>Level III.</p>

<p>Hypertrophic cardiomyopathy has a range of clinical severity in children. Treatment options are limited, mainly on account of small patient size. Disopyramide is a sodium channel blocker with negative inotropic properties that effectively reduces left ventricular outflow tract gradients in adults with hypertrophic cardiomyopathy, but its efficacy in children is uncertain. A retrospective chart review of patients ⩽21 years of age with hypertrophic cardiomyopathy at our institution and treated with disopyramide was performed. Left ventricular outflow tract Doppler gradients before and after disopyramide initiation were compared as the primary outcome measure. Nine patients received disopyramide, with a median age of 5.6 years (range 6 days-12.9 years). The median left ventricular outflow tract Doppler gradient before initiation of disopyramide was 81 mmHg (range 30-132 mmHg); eight patients had post-initiation echocardiograms, in which the median lowest recorded Doppler gradient was 43 mmHg (range 15-100 mmHg), for a median % reduction of 58.2% (p=0.002). With median follow-up of 2.5 years, eight of nine patients were still alive, although disopyramide had been discontinued in six of the nine patients. Reasons for discontinuation included septal myomectomy (four patients), heart transplantation (one patient), and side effects (one patient). Disopyramide was effective for the relief of left ventricular outflow tract obstruction in children with hypertrophic cardiomyopathy, although longer-term data suggest that its efficacy is not sustained. In general, it was well tolerated. Further study in larger patient populations is warranted.</p>

<p><strong>OBJECTIVES: </strong>To describe the prevalence of and identify risk factors for acute occlusive arterial injury (AOAI) in a large volume pediatric cardiac catheterization laboratory.</p>

<p><strong>BACKGROUND: </strong>AOAI is a known complication after pediatric cardiac catheterization. Prevalence and risk factors in the modern era are incompletely described.</p>

<p><strong>METHODS: </strong>A retrospective cohort study including all cardiac catheterization procedures performed between January 1, 2005 and June 30, 2010 was performed. Case status was defined by ≥1 of the following: exam consistent with occlusive arterial injury, use of an anticoagulant within 48 hr of catheterization to restore or maintain patency of the artery, or documented occlusive arterial injury by radiologic study.</p>

<p><strong>RESULTS: </strong>3,254 patients had 5,715 catheterization procedures, which included 3,859 arterial access events. 167 cases of AOAI were identified for an overall prevalence of 4.3% among arterial access events. Multiple logistic regression identified independent risk factors: weight category [&lt;4 kg: odds ratio (OR) 4.5 (95% CI: 2.6-7.7), P &lt; 0.001; 4-6 kg: OR 2.1 (1.3-3.5), P = 0.002, compared to 6-8 kg referent group]; largest catheter outer diameter French size [OR 1.6 (1.3-1.9), P &lt; 0.001]; final activated clotting time (ACT) &lt;250 sec [OR 1.9 (1.4-2.7), P &lt; 0.001]; and need for arterial catheter exchange [OR 1.8 (1.02-3.2), P = 0.04].</p>

<p><strong>CONCLUSIONS: </strong>AOAI occurred in 4.3% of pediatric cardiac catheterizations, and was most likely in smaller children and those with larger arterial catheters. Risk was also independently increased by arterial catheter exchange and having a final ACT &lt;250 sec. These data act as an important benchmark and identify areas for intervention for future studies.</p>