Single ventricle pulmonary arteriovenous malformations are poorly understood and variably assessed in published literature. To improve our understanding of single ventricle pulmonary arteriovenous malformations and facilitate multi-centre studies, it will be necessary to have uniform clinical practice patterns among paediatric heart institutions.

The aim of this study was to assess paediatric interventional cardiologists’ clinical perspectives and practice patterns for diagnosing single ventricle pulmonary arteriovenous malformations.

We surveyed paediatric interventional cardiologists using the Congenital Cardiovascular Interventional Consortium listserv. A single survey was distributed electronically with two subsequent reminder emails. Voluntary participants completed the anonymous survey electronically via RedCap.

Among 253 Congenital Cardiovascular Interventional Consortium members, a total of 55 (21.7%) paediatric cardiology interventional attending physicians completed the survey. There was near unanimity (98%) that pulmonary arteriovenous malformations develop due to lack of hepatic vein blood flow to the lungs; however, there was wide variation among practice patterns. A minority (20%) of respondents perform bubble contrast echocardiograms (bubble studies) more than half the time pre-Fontan, whereas many (31%) almost never (< 5% of cases) perform bubble studies pre-Fontan. Most respondents reported that they did not perform bubble studies because results do not impact clinical decision making pre-Fontan (56%) or post-Fontan (60%). Many respondents (49%) do not have a typical volume of agitated saline that they inject for bubble studies.

Clinical practice patterns vary widely among paediatric cardiology interventionalists. A standardised clinical approach, new diagnostic tools, or both are needed to standardise our field’s approach to diagnosing, studying, and treating single ventricle pulmonary arteriovenous malformations.

Individuals with single ventricle physiology who are palliated with superior cavopulmonary anastomosis (Glenn surgery) may develop pulmonary arteriovenous malformations. The traditional tools for pulmonary arteriovenous malformation diagnosis are often of limited diagnostic utility in this patient population. We sought to measure the pulmonary capillary transit time to determine its value as a tool to identify pulmonary arteriovenous malformations in patients with single ventricle physiology.

We defined the angiographic pulmonary capillary transit time as the number of cardiac cycles required for transit of contrast from the distal pulmonary arteries to the pulmonary veins. Patients were retrospectively recruited from a single quaternary North American paediatric centre, and angiographic and clinical data were reviewed. Pulmonary capillary transit time was calculated in 20 control patients and compared to 20 single ventricle patients at the pre-Glenn, Glenn, and Fontan surgical stages (which were compared with a linear-mixed model). Correlation (Pearson) between pulmonary capillary transit time and haemodynamic and injection parameters was assessed using angiograms from 84 Glenn patients. Five independent observers calculated pulmonary capillary transit time to measure reproducibility (intraclass correlation coefficient).

Mean pulmonary capillary transit time was 3.3 cardiac cycles in the control population, and 3.5, 2.4, and 3.5 in the pre-Glenn, Glenn, and Fontan stages, respectively. Pulmonary capillary transit time in the Glenn population did not correlate with injection conditions. Intraclass correlation coefficient was 0.87.

Pulmonary angiography can be used to calculate the pulmonary capillary transit time, which is reproducible between observers. Pulmonary capillary transit time accelerates in the Glenn stage, correlating with absence of direct hepatopulmonary venous flow.