Pulmonary vascular resistance and compliance in individuals with trisomy 18

Individuals with trisomy 18 (T18) usually have congenital heart disease, often with pulmonary hypertension, which is associated with poor outcomes. This study aimed to explore the characteristics of pulmonary circulation including pulmonary vascular resistance (Rp) and compliance (Cp) among them. We retrospectively reviewed cardiac catheterization data in subjects with T18, trisomy 21 (T21), and without chromosomal anomaly (control group) who were referred due to heart failure associated with ventricular septal defect between 2000 and 2020. Pulmonary hemodynamic parameters including Rp and Cp were compared between these groups. We studied 20 subjects with T18, 88 subjects with T21, and 240 control subjects. There was no significant difference in age (T18: 4.6 [3.0-6. 9] vs. T21: 2.8 [1.9-4.0] vs. control: 2.9 [1.6-3.2] months, p = 0.06) and mean pulmonary arterial pressure (T18: 41 [33-49] vs. T21: 35 [30-41] vs. control: 36 [28-43] mmHg, p = 0.121) between the groups. The pulmonary to systemic blood flow ratio (Qp/Qs) (p = 0.983), Rp (p = 0.449), and Cp (p = 0.195) did not differ between T18 and control groups. However, Qp/Qs and Cp in T18 group were significantly greater than that in T21 group (T18: Qp/Qs: 3.4 [2.3-5.2] vs. T: 21 2.3 [1.7-3.7], p = 0.001. Cp: 3.5 [2.3-5.5] vs. 2.3 [1.6-3.1] mmHg/mL/m² , p = 0.007), while Rp was identical between the groups (T18: 2.0 [1.6-3.3] vs. T21: 2.3 [1.7-3.7], p = 0.386). The pulmonary circulation in T18 subjects differed from that observed in T21 subjects, and identical to that observed in control subjects. Pulmonary hypertension is expected to be normalized after reasonable corrective surgery in T18 patients with congenital heart disease.