Histological analysis of lung tissue and pulmonary vessels in cardiac surgery patients with mitral valve disease and pulmonary hypertension
S Barbarash, I Lyapina, A Kutikhin, L Bogdanov, E Dren, T Martynyuk, O BarbarashAbstract
Abstract
The aim: to study the morphological features of lung tissue and pulmonary vessels in patients with pulmonary hypertension (PH) associated with acquired mitral valve (MV) disease, with indications for surgical treatment.
Material and methods
The cross-sectional study included 105 patients with acquired MV disease of non-infectious genesis (median age 60.0 [51.0; 66.0] years, men 55.24%) who underwent valve correction with artificial circulation in the period from 2024 to March 2025. Verification of PH was performed using right heart catheterization before MV correction. In 26 patients with MV disease and PH and in 12 patients without PH, intraoperative puncture biopsy of lung tissue was performed to assess changes in the lung parenchyma and microvascular bed.
Results
For patients with MV disease and PH, the condition of the arterioles was characterized by a larger area of hypertrophied intima and predominantly the presence of pandemic thrombosis (34.6%). In patients with MV disease without PH, partial thrombosis of the arterioles was more often present (41.66%) and in 41.66% patients full-blooded arterioles were observed. It was noted, that the presence of the level of estimated systolic pulmonary artery pressure 38 mm Hg and higher according to echocardiography before surgery has a moderate inverse correlation with the area of the vascular wall (Kendall-Tau rank correlation coefficient –0.34; p = 0.01), a moderate direct correlation with the greatest thickness at the site of arteriole wall hypertrophy (0.39; p = 0.04) according to the morphometry of the pulmonary vessels. A moderate inverse relationship was found between the value of tricuspid annular plane systolic excursion (1.7 cm or more) with the greatest thickness at the site of arteriole wall hypertrophy (–0.47; p = 0.04). MV stenosis is associated with the presence of thrombosed capillaries (odds ratio (OR) 8.75 [0.95% confidence interval (CI) 1.1; 69.5], p = 0.029), and focal interstitial fibrosis (OR 10.66 [0.95% CI 0.89; 126.78], p = 0.046). The presence of mitral stenosis has a moderate correlation with perivascular fibrosis (Kendall-Tau = 0.41; p = 0.005). The presence of a body mass index of 25 kg/m2 or higher is associated with a reduced chance of arteriole media thickening (OR 0.15 [0.95% CI 0.02; 1.01] p=0.03).
Conclusion
The severity of pulmonary hypertension and right ventricular dysfunction according to echocardiography data before correction of the MV disease may reflect morphometric changes in the pulmonary vessels. The presence of MV stenosis is associated with a more than 8-fold increase in the odds of the presence of thrombosed capillaries and a 10-fold increase in the odds of focal interstitial fibrosis. The presence of excess body weight or obesity is associated with an 85% decrease in the odds of arteriole media thickening according to the results of pulmonary vessel morphometry.