CHRONIC MITRAL INSUFFICIENCY

慢性二尖瓣关闭不全

• 批准号: 3966644
• 负责人: R MARCH
• 金额: --
• 依托单位: NATIONAL HEART, LUNG, AND BLOOD INSTITUTE
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/3966644
• 关键词: cardiac output; disease /disorder model; heart circulation; heart disorder diagnosis; heart function; heart surgery; heart ventricle; mitral valve; mitral valve insufficiency; model design /development; oxygen consumption; prosthetic heart valve; ultrasound blood flow measurement

This laboratory study tested the hypothesis that left ventricular function following mitral valve replacement may be better preserved by retaining the tethering effect of the mitral valve apparatus in chronic mitral regurgitation. A chronic model of mitral regurgitation has been developed an extensively studies in sheep. Due to the progressive enlargement of an anterior mitral leaflet defect, there were significant increases in left ventricular mass, wall thickness, LV mass to body weight ratio, end-diastolic volume, stroke volume and ejection fraction over a 7-8 month period compared to controls. Mitral annular - papillary muscle discontinuity following mitral valve replacement in chronic, volume overloaded ventricles, led to a significant increase in the end-diastolic volume thus creating an increased "effective" preload. This resulted in an increased stroke volume secondary to increased equatorial, minor axis shortening. Despite this increase in forward flow, the reserve of the left ventricle with chronic mitral regurgitation to perform pressure-volume work was severely impaired with dramatic, significant decreases in maximum systolic blood pressure and max dp/dt at matched heart rates and preload after all chordae tendinae were severed. These data show that maintenance of mitral annular-papillary muscle continuity following mitral valve replacement preserves left ventricular function in setting of chronic volume overload secondary to mitral regurgitation.

这项实验室研究验证了左心室功能 二尖瓣置换术后， 慢性二尖瓣狭窄时二尖瓣器的栓系效应 返流程度 二尖瓣返流的慢性模型已经建立， 在羊身上进行了广泛的研究。 由于一个不断扩大的 二尖瓣前叶缺损，左室舒张功能显著增加， 心室质量、室壁厚度、LV质量与体重比， 7-8个月内的舒张末期容积、每搏输出量和射血分数 与对照组相比。 二尖瓣环-乳头肌 慢性二尖瓣置换术后的不连续性，容量 心室负荷过重，导致舒张末期 因此产生增加的“有效”预载。 这导致 继发于赤道短轴增加的每搏输出量增加 缩短。 尽管这一增长，在前进的流动，储备的左 慢性二尖瓣返流心室进行压力-容积功 严重受损， 匹配心率和前负荷时的收缩压和最大dp/dt 在所有腱索都被切断之后 这些数据表明， 二尖瓣环-乳头肌连续性 置换术在慢性心功能不全患者中保留了左心室功能 继发于二尖瓣返流的容量超负荷。