Right-Ventricular Function and Morphology after Experimental Pulmonary Valve Regurgitation: First Experience with a Juvenile Pig Model

Background: Right ventricular (RV) failure secondary to RV volume or pressure overload is frequently encountered in patients with congenital heart disease. While left ventricular (LV) failure is increasingly well characterized, the functional and structural features of RV failure are insufficiently understood/characterized. In the present study, we aimed to characterize the influence of experimentally induced pulmonary valve (PV) regurgitation (PR) on the RV morphology and function in a juvenile porcine animal model.

Method: One-month-old piglets underwent surgical PR induction. The animals were randomly assigned to the PR or the control group. After left-lateral thoracostomy and local opening of the pericardium, the PV cusps of the lateral hemi-circumference of the PV were attached to the pulmonary artery wall by external placement of plication sutures, thus creating PR. In control group animals, a sham procedure was conducted. After 10 weeks, the animals underwent cardiac magnetic resonance imaging (MRI) to objectify the degree of PR, static and dynamic measurements of the RV and the LV dimensions and functions, respectively. The parameters were compared between PR group and control group animals.

Results: Twelve piglets (weight: 15 ± 2.5 kg) were included. Four animals died, thereof two due to immediate perioperative RV failure, one due to ventricular arrhythmia after central line placement, and one due to pulmonary infection 9 days post-OP. The remaining eight animals (PV group = 5, control group = 3) underwent MRI after 70 ± 2 days with a weight of 47 ± 7.9 kg. The PR group showed increased RV stroke volume (95 ± 20 vs. 64 ± 13 mL; p = 0.041) and pulmonary valve regurgitation fraction (23 ± 17 vs. 0.3 ± 0.02%; p = 0.031) compared with the control group. The mean PV gradient was higher in the PR compared with the control group (2.9 ± 0.6 vs. 1.1 ± 0.3 mm Hg; p = 0.002). The RV end diastolic volume (PR: 130 ±21 mL, control: 87 ± 16 mL; p = 0.012), end systolic volume (PR: 35 ± 10 mL, control: 23 ± 2.4 mL; p = 0.043) and myocardial mass (PR: 34 ± 4 g, control: 23 ± 4 g; p = 0.05) were increased in the PR group, while the RV ejection fractions were comparable in both groups (PR: 73 ± 8% control: 73 ± 3%; p = 0.046). The left-ventricular and atrial parameters did not differ between the groups.

Conclusion: Despite vulnerability and perioperative risk in this young animal model, the model results in reproducible induction of PR and RV volume overload. The effects can be objectified using cardiac MRI. The model will serve for further studies to investigate structural and metabolic characteristics of PR-induced RV failure, also during longer time-courses.

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Publikationsverlauf

Artikel online veröffentlicht:
28. Januar 2023