Right Atrial Tissue Morphology in Different Acquired Heart Diseases: A Pilot Study

Despite scientific progress, diseases of circulatory system are still the most common cause of mortality in Latvia and all Europe. Approximately 1–2% of adult population in developed countries has heart failure, with the prevalence rising to ≥ 10% among persons 70 years of age or older. One of the main principles of heart failure treatment is to target the underlying cause, for example, revascularisation and valve surgery. Understanding the pathophysiology and its clinical implications are important for the cardiovascular surgeon, because the therapeutic options may improve a patient’s outcome.
The aim of this study was to identify appearance and distribution of apoptosis, homeostasis regulating factors, innervations and ischemia markers in right atrial tissue in different acquired heart diseases.
In Pauls Stradiņš Clinical University Hospital during elective heart surgery were taken right atrial tissue fragments from 6 patients. The mean age was (mean ± SD) 70.3 ± 9.1 years (range 58–83 years) and there were 4 female patients. Tissues were processed for apoptosis, protein-gene peptide 9.5 (PGP 9.5), human atrial natriuretic peptide (hANUP), vascular endothelial growth factor (VEGF), chromogranin A and endothelin by means of biotin-streptavidin immunohistochemistry. In all patients, a moderate to severe myocyte degeneration and vacuolisation was observed. In three patients, significant vascular sclerosis was found. The apoptotic index ranged from 24% to 80%.
Mean number of TUNEL positive cardiomyocytes was significantly different among all specimens.
All examined patients showed different expression of PGP 9.5. Numerous hANUP secreting cells were detected in all specimens, except patient No. 2, where this factor was detected in moderate cells. Few vascular endothelial growth factors were observed in endothelial cells in all specimens. Only in 2 patients, blood vessels contained endothelin positive endotheliocytes. Mostly this factor was seen in epicardium Different expression of PGP 9.5, hANUP, VEGF, chromogranin A and endothelin in right atrial tissue might characterise pathogenesis of different acquired heart diseases.
Large variation of apoptotic index seems to correlate to larger volume and longer untreated history of the affected disease in our pilot study patients in Latvia.