Griffin B P, Flachskampf F A, Reimold S C, Lee R T, Thomas J D
Non-invasive Cardiac Laboratory, Massachusetts General Hospital, Boston.
Eur Heart J. 1994 May;15(5):681-5. doi: 10.1093/oxfordjournals.eurheartj.a060567.
The slope and pressure half-time of the aortic regurgitant velocity spectrum have been used as non-invasive markers of regurgitant severity. Recent in vitro and theoretical work, however, has suggested a confounding effect of systemic vascular resistance and left ventricular compliance on these parameters. To study this situation in vivo, we have investigated the determinants of the aortic regurgitant velocity profile in an animal model of aortic regurgitation in which the regurgitation was induced surgically and in which the afterload was varied pharmacologically. Specifically, we examined the relationship of slope and pressure half-time of the aortic regurgitant velocity profile to the severity of aortic regurgitation under varying conditions of afterload using multilinear analysis. Slope varied directly with regurgitant orifice area and inversely with systemic vascular resistance and both left ventricular and aortic compliance (all P < 0.001). Pressure half-time related to these variables in the opposite direction. When the regurgitant orifice was variable in size, slope related directly (P < 0.001) and half-time inversely to the severity of the aortic regurgitation (the clinically expected response). In contrast, when the regurgitant orifice area was constant, slope varied inversely (P < 0.001) and half-time varied directly (P < 0.07) with the severity of the aortic regurgitation. Following nitroprusside infusion, slope tended to increase (P = 0.08) and pressure half-time tended to shorten (P = 0.08) despite a significant reduction in the regurgitant fraction (P = 0.009). Similarly, following dopamine infusion, a significant increase in regurgitant fraction (P = 0.01) was associated with a slight fall in aortic regurgitation slope and a lengthening of the half-time.(ABSTRACT TRUNCATED AT 250 WORDS)
主动脉反流速度频谱的斜率和压力半衰期已被用作反流严重程度的无创性指标。然而，最近的体外和理论研究表明，体循环血管阻力和左心室顺应性对这些参数有混杂影响。为了在体内研究这种情况，我们在主动脉反流动物模型中研究了主动脉反流速度曲线的决定因素，在该模型中，反流通过手术诱导，后负荷通过药理学方法改变。具体而言，我们使用多线性分析，研究了在不同后负荷条件下，主动脉反流速度曲线的斜率和压力半衰期与主动脉反流严重程度之间的关系。斜率与反流口面积直接相关，与体循环血管阻力以及左心室和主动脉顺应性呈反比（所有P<0.001）。压力半衰期与这些变量的关系则相反。当反流口大小可变时，斜率与主动脉反流严重程度直接相关（P<0.001），半衰期与之呈反比（临床预期反应）。相比之下，当反流口面积恒定时，斜率与主动脉反流严重程度呈反比（P<0.001），半衰期与之呈正比（P<0.07）。输注硝普钠后，尽管反流分数显著降低（P=0.009），但斜率趋于增加（P=0.08），压力半衰期趋于缩短（P=0.08）。同样，输注多巴胺后，反流分数显著增加（P=0.01），同时主动脉反流斜率略有下降，半衰期延长。（摘要截断于250字）
