Scimitar syndrome is a rare CHD composed of partial anomalous pulmonary venous connection from the right lung, via a scimitar vein, to the inferior vena cava rather than the left atrium. Genetic conditions associated with scimitar syndrome have not been well investigated at present.

Our study included patients with scimitar syndrome diagnosed at Texas Children’s Hospital from January 1987 to July 2020. Medical records were evaluated to determine if genetic testing was performed, including chromosomal microarray analysis or whole-exome sequencing. Copy number variants identified as pathogenic/likely pathogenic and variants of unknown significance were collected. Analyses of cardiac and extracardiac findings were performed via chart review.

Ninety-eight patients were identified with scimitar syndrome, 89 of which met inclusion criteria. A chromosome analysis or chromosomal microarray analysis was performed in 18 patients (20%). Whole-exome sequencing was performed in six patients following negative chromosomal microarray analysis testing. A molecular genetic diagnosis was made in 7 of 18 cases (39% of those tested). Ninety-six per cent of the cohort had some type of extracardiac finding, with 43% having asthma and 20% having a gastrointestinal pathology. Of the seven patients with positive genetic testing, all had extracardiac anomalies with all but one having gastrointestinal findings and 30% having congenital diaphragmatic hernia.

Genetic testing revealed an underlying diagnosis in roughly 40% of those tested. Given the relatively high prevalence of pathogenic variants, we recommend chromosomal microarray analysis and whole-exome sequencing for patients with scimitar syndrome and extracardiac defects.

Patients with total anomalous pulmonary venous connection can be problematic, particularly those with mixed-type pathology. We aimed to describe a cohort of patients with mixed-type anomalous drainage, highlighting the treatment challenges, and identifying risk factors for poor outcome.

We reviewed the clinical records of patients who underwent repair for mixed-type total anomalous pulmonary venous connection between 1986 and 2015.

A total of 19 patients were identified. The median age and weight of patients at surgery were 18 days (with a range from 1 to 185) and 3.4 kg (with a range from 1.9 to 6.5), respectively. Venous anatomy included a combination of duplicate supracardiac (four), supracardiac and cardiac (11), and supracardiac and infracardiac (four) drainage. Out of 19 patients, six (32%) died within 30 days or the initial hospital stay; two additional patients died from progressive pulmonary vein stenosis at 72 and 201 days, respectively, resulting in 42% mortality within the 1st year. Follow-up data were available for 8/11 long-term survivors. The median follow-up period was 7.3 years (with a range from 1.8 to 15.7). Only one patient underwent re-intervention for recurrent pulmonary vein stenosis. For surgical mortality, no statistically significant risk factors were identified, although the risk trended to be higher (p⩽0.1) with lower age and weight, an infracardiac component, and prolonged cardiopulmonary bypass. For 1-year mortality, the risk became significant (p⩽0.05) with a lower weight (p=0.01), an infracardiac component (p=0.03), and prolonged cardiopulmonary bypass (p=0.04).

The surgical and 1-year mortality in patients with mixed-type total anomalous pulmonary venous connection is high. On the other hand, among patients who survive past the 1st year, most have good outcomes without subsequent sequelae.