Post-mortem right heart sample cohort
A second cohort of twelve biopsies of the right heart chambers from postmortem heart samples of patients diagnosed when living as severe pulmonary hypertension were included. This cohort was created to evaluate the hazard effect of increased systolic pulmonary artery pressure (sPAP) on the development of fibrosis in the right heart chambers.
The heart was photographed, and the macroscopic characteristics were taken, and sections were made for histological study. Samples were taken from the right atrial and the right ventricular free walls. We took photographs of the longitudinal section from the atrium’s anterior wall, from the origin of the appendage to the tricuspid valve, and a transverse section of the ventricle in the middle portion of the free wall, covering the entire thickness of the wall.
The samples were processed with the histological technique of ”paraffin inclusion”. They were stained with the Masson technique to quantify the percentage of right atrial and right ventricular fibrous tissue, dividing the field of observation of the microscope into quarters. Two independent observers gave the percentage values, and a consensus value was obtained when there were differences. Microscopic photographs were taken of the most representative areas (Figures 2-3 ).
The study was carried out following the Declaration of Helsinki and was approved by the Ethics and Research Committee of the National Institute of Cardiology Ignacio Chavez. Reference number: PT-17-087.