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Pulmonary vascular changes induced by congenital obstruction of pulmonary venous return
1Department of Thoracic and Cardiovascular Surgery, Tohoku University School of Medicine, Sendai, Japan.
Insights
Pulmonary venous obstruction (PVO) causes significant changes in pulmonary arteries and veins, including thickening and fibrosis. These changes may be reversible, offering hope for treating associated pulmonary hypertension.
Area of Science:
- Cardiovascular Pathology
- Pediatric Cardiology
Background:
- Pulmonary venous obstruction (PVO) is linked to pulmonary hypertension and impaired cardiac repair.
- Understanding PVO's vascular effects is crucial for pediatric cardiac care.
Purpose of the Study:
- To investigate the histological changes in pulmonary vasculature in congenital PVO.
- To compare these changes with those in ventricular septal defect (VSD).
Main Methods:
- Histological examination of pulmonary vasculature from 8 congenital PVO cases (mitral stenosis, cor triatriatum).
- Histometrical analysis of medial thickness and intimal changes in pulmonary arteries and veins.
- Comparative analysis with pulmonary vasculature from VSD cases.
Main Results:
- PVO cases exhibited medial thickening and intimal fibrosis in pulmonary arteries and veins, with lymphangiectasia.
- Pulmonary artery medial thickness correlated with systolic pulmonary arterial pressure (PAP).
- Vascular changes in PVO were more pronounced than in VSD cases.
Conclusions:
- Congenital PVO causes progressive vascular changes (medial thickening, intimal fibrosis, lymphangiectasia).
- Absence of plexiform lesions suggests potential reversibility of PVO-induced pulmonary hypertension.
Background:
Pulmonary venous obstruction (PVO) induces pulmonary arterial hypertension, as well as pulmonary venous hypertension, and jeopardizes the repair of cardiac lesions.
Methods:
Four cases of congenital mitral stenosis and 4 cases of cor triatriatum (Lucas type A), ages ranging from 2 months to 16 years, were histologically examined on pulmonary vasculature. Histometrical analysis was performed on medial thickness and intimal changes of both pulmonary arteries and veins. For comparison, the examination of pulmonary vasculature in ventricular septal defect (VSD) cases was also performed.
Results:
Medial thickening and intimal fibrosis, in both pulmonary arteries and veins with widespread lymphangiectasia, were characteristic vascular changes of PVO cases. Medial thickness of pulmonary arteries was correlated with preoperative pulmonary arterial pressure (PAP) (r = 0.77, p = 0.03 for systolic PAP), and greater than that of VSD cases. Medial thickness of pulmonary veins was also greater in PVO cases. Intimal fibrosis of pulmonary arteries and veins was seen extensively at the advanced ages, whereas no plexiform lesions or more advanced stages of pulmonary vascular disease were present.
Conclusions:
Congenital PVO induced progressive medial thickening and intimal fibrosis in pulmonary arteries and veins accompanied by lymphangiectasia. However, no plexiform lesions or more advanced stages of pulmonary vascular disease were present, which may explain the reversibility of pulmonary hypertension due to congenital PVO.