Adaptations of venus peripheral circulation in mild to moderate tricuspid regurgitation

The aim of the study was to assess the hypothetic relationship between right atrial mechanoreceptors stimulation due to mild to moderate tricuspid regurgitation and forearm venous tone. Method: The study group included 15 patients (9 males, 6 females, average years range 25-55) with mild to moderate tricuspid regurgitation (TR) measured by EchocardioDoppler examination (CW maximum regurgitation velocity included between 2.0 and 3.6 m/s). The study group was compared with sex and age matched control group (N) with no or trivial tricuspid regurgitation (CW maximum regurgitation velocity <2.0 2.0 m/s). Exclusion criteria were: congenital heart disease, heart failure, pericardial disease, cardiac arrhythmias, arterial peripheral, Venous disease, neuro-vascular compression syndrome. In condition of no pharmacological treatment each patient was submitted to mercury straingauge plethysmography (PSG) at 20-40-60 mmHg venous occlusion straingauge; straingauge was applied at maximum right forearm diameter at zero phlebostatic level right atrium). Each examination was performed after 10’ of rest (forearm abduction <30°; physiological breath; temperature: 24-26 °C). We calculated the following plethysmographic parameters: venous distensibility (VD) and venous tone (VT) at 60-40 mmHg occlusions, time of total emptying (tTE) at 60 mmHg occlusion and venous pressure (VP) estimated by a linear regression on 20-40-60 MVIV (maximal venous incremental volume) points. The exams were performed by 2 operators in single blind. The T test for unpaired data was performed for statical analysis. Results: our data showed in TR group a significant increase of VD (25.5%. p<0.05) and of tTE (91.8%, p < 0.05), decrease of VT (29.6%, p < 0.05), without difference in VP. Conclusion: this phenomenon can be explained as consequence of a loss in venous-constrictor sympathetic drive on venous wall probably related to stimulation or right atrial mechano-receptors.