Tricuspid valvular dynamics and 3-dimensional geometry in awake and anesthetized sheep

Abstract Objectives Clinical and experimental tricuspid valve physiology data is derived predominantly from anesthetized subjects, but normal tricuspid valve geometry and dynamics may be altered by general anesthesia and mechanical ventilation. We set out to investigate three-dimensional geometry and dynamics of the tricuspid valve complex in awake and anesthetized sheep. Methods While on cardiopulmonary bypass and with the heart beating, 6 adult sheep (50±8 kg) underwent implantation of 6 sonomicrometry crystals around the tricuspid annulus. One crystal was implanted on the anterior, posterior and septal papillary muscle tip, four on the right ventricular free wall, and one on its apex. Pressure transducers were placed in both ventricles. Sonomicrometry and pressure transducer cables were externalized to subcutaneous buttons. After 7 days of recovery, hemodynamic and sonomicrometry data were recorded with animals awake and anesthetized. Results Hemodynamic parameters did not differ between groups. Tricuspid annular area contraction decreased with anesthesia (16.4±4.2 vs. 11.2±3.2%, p=0.047) as did tricuspid annular perimeter contraction (8.1±2.2 vs. 5.4±1.7%, p=0.050), predominantly due to reduced contraction of the septal annulus (10.5±2.9 vs. 7.5±3.5%, p=0.019). Tricuspid annular height did not differ between groups. Minimal distance from anterior, posterior and septal papillary muscle tips to the annular plane did not change with anesthesia. Regional right ventricle free wall contraction was depressed under anesthesia in anterior (16.3±3.1 vs. 12.3±2.2%, p=0.027) and lateral (14.9±1.3 vs. 11.5±2.8%, p=0.016) segments, while the posterior remained unchanged. Conclusions General anesthesia did not alter tricuspid annular or subvalvular three-dimensional geometry but reduced right ventricular contraction and tricuspid annular dynamics.