Summary: To evaluate the effect of lower intensity anticoagulation therapy in patients with mechanical prosthetic valves, laboratory based hematological assays including prothrombin time (PT), activity of factor X, a...Summary: To evaluate the effect of lower intensity anticoagulation therapy in patients with mechanical prosthetic valves, laboratory based hematological assays including prothrombin time (PT), activity of factor X, antithrombin Ⅲ (AT Ⅲ), D dimer, fibrinogen (Fg) and platel et al pha granular membrane protein (GMP 140) were performed in 65 patients who had been on warfarin treatment for over one month. The patients were assigned to 3 groups on the basis of their International Normalized Ratios (INR), ranging from 2.00 to 2.50; 2.51 to 3.00; 3.01 to 4.50, respectively. The results showed that the D dimer, Fg, GMP 140 levels were higher after mechanical valve replacement than those before operation, indicating the activation of coagulation and fibrinolysis system and the damage of platelets. Lower intensity anticoagulation therapy (INR 2 00 to 2.50) could effectively inhibit the activity of factor X and increase the level of AT Ⅲ. There were no appreciable differences among D dimer, Fg, GMP 140 and AT Ⅲ in the 3 anticoagulation intensity groups. These results suggest that in patients with new generation mechanical prosthetic valves, target anticoagulation level (INR 2 00 to 2.50) may result in good protection from thrombo embolism.展开更多
Objective To assess the influence of mimic cardiac rate on hydrodynamics of different mechanical prosthetic cardiac valves. Methods US-made CarboMedics bileaflet valve, China-made Jiuling bileaflet valve and C-L tilti...Objective To assess the influence of mimic cardiac rate on hydrodynamics of different mechanical prosthetic cardiac valves. Methods US-made CarboMedics bileaflet valve, China-made Jiuling bileaflet valve and C-L tilting disc valve were tested via a pulsatile flow simulator in the aortic position. Testing conditions were set at mimic cardiac rates of 55 bpm, 75 bpm, 100 bpm with a constant mimic cardiac output of 4 L/min. The mean pressure differences (ΔP), leakage volumes (LEV) and closing volumes (CLV) across each valve, and effective orifice areas (EOA) were analyzed. Results Within physiological range, ΔP, LEV, and CLV decreased as mimic cardiac rate increased, with a large extent of variance. EOA increased along with an increase in mimic cardiac rate. It was a different response in terms of cardiac rate alteration for different types of mechanical prosthetic cardiac valves. Conclusion Mimic cardiac rate change affects hydrodynamics of mechanical prosthetic cardiac valves. Within physiological range, the hydrodynamic of prosthetic bileaflet valve is better than that of tilting disc valve.展开更多
文摘Summary: To evaluate the effect of lower intensity anticoagulation therapy in patients with mechanical prosthetic valves, laboratory based hematological assays including prothrombin time (PT), activity of factor X, antithrombin Ⅲ (AT Ⅲ), D dimer, fibrinogen (Fg) and platel et al pha granular membrane protein (GMP 140) were performed in 65 patients who had been on warfarin treatment for over one month. The patients were assigned to 3 groups on the basis of their International Normalized Ratios (INR), ranging from 2.00 to 2.50; 2.51 to 3.00; 3.01 to 4.50, respectively. The results showed that the D dimer, Fg, GMP 140 levels were higher after mechanical valve replacement than those before operation, indicating the activation of coagulation and fibrinolysis system and the damage of platelets. Lower intensity anticoagulation therapy (INR 2 00 to 2.50) could effectively inhibit the activity of factor X and increase the level of AT Ⅲ. There were no appreciable differences among D dimer, Fg, GMP 140 and AT Ⅲ in the 3 anticoagulation intensity groups. These results suggest that in patients with new generation mechanical prosthetic valves, target anticoagulation level (INR 2 00 to 2.50) may result in good protection from thrombo embolism.
文摘Objective To assess the influence of mimic cardiac rate on hydrodynamics of different mechanical prosthetic cardiac valves. Methods US-made CarboMedics bileaflet valve, China-made Jiuling bileaflet valve and C-L tilting disc valve were tested via a pulsatile flow simulator in the aortic position. Testing conditions were set at mimic cardiac rates of 55 bpm, 75 bpm, 100 bpm with a constant mimic cardiac output of 4 L/min. The mean pressure differences (ΔP), leakage volumes (LEV) and closing volumes (CLV) across each valve, and effective orifice areas (EOA) were analyzed. Results Within physiological range, ΔP, LEV, and CLV decreased as mimic cardiac rate increased, with a large extent of variance. EOA increased along with an increase in mimic cardiac rate. It was a different response in terms of cardiac rate alteration for different types of mechanical prosthetic cardiac valves. Conclusion Mimic cardiac rate change affects hydrodynamics of mechanical prosthetic cardiac valves. Within physiological range, the hydrodynamic of prosthetic bileaflet valve is better than that of tilting disc valve.
