Renal blood flow in heart failure patients during exercise
Renal blood flow in heart failure patients during exercise
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DOI：
10.1152/ajpheart.00394.2004
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发表时间：
2004-12-01
影响因子：
4.8
通讯作者：
Sinoway, LI
中科院分区：
文献类型：
--
作者：
Momen, A;Bower, D;Sinoway, LI
在运动过程中，反射性肾血管收缩维持血压，并帮助重新分配血液流向收缩肌肉。心力衰竭（HF）的运动不耐受被认为与活动肌肉灌注减少有关。我们研究了10例心衰患者和9例对照患者在3种肌肉收缩模式下静态握力（HG）与肾血流速度（RBV；双工超声）的时间关系。与对照组相比，在最大自愿收缩40%时的疲劳HG（方案1）导致HF中RBV的更大降低（组主效应：P < 0.05）。在方案1的早期阶段，HG早期RBV的减少往往更为突出。在hg后循环停止（分离肌肉代谢反射）期间，两组观察到相似的RBV。分级强度的短时间（15秒）HG治疗（方案2，调动肌肉机械反射和/或中枢指挥）导致HF患者RBV比对照组下降更大（P < 0.03）。方案3，自愿和非自愿肱二头肌收缩（消除中枢命令），导致HF患者肾血管收缩相似的增加（n = 4）。在运动的早期阶段，HF患者的RBV比对照组有更大的下降。这种效果不太可能是由于超反射或中央命令。因此，我们的数据表明，心力衰竭患者的肌肉机械反射活动增强，并有助于肾脏血管收缩。我们相信这种代偿机制有助于保持心力衰竭患者运动肌肉的血流量。
During exercise, reflex renal vasoconstriction maintains blood pressure and helps in redistributing blood flow to the contracting muscle. Exercise intolerance in heart failure (HF) is thought to involve diminished perfusion in active muscle. We studied the temporal relationship between static handgrip (HG) and renal blood flow velocity (RBV; duplex ultrasound) in 10 HF and in 9 matched controls during 3 muscle contraction paradigms. Fatiguing HG (protocol 1) at 40% of maximum voluntary contraction led to a greater reduction in RBV in HF compared with controls ( group main effect: P < 0.05). The reduction in RBV early in HG tended to be more prominent during the early phases of protocol 1. Similar RBV was observed in the two groups during post-HG circulatory arrest ( isolating muscle metaboreflex). Short bouts (15 s) of HG at graded intensities ( protocol 2; engages muscle mechanoreflex and/or central command) led to greater reductions in RBV in HF than controls (P < 0.03). Protocol 3, voluntary and involuntary biceps contraction ( eliminates central command), led to similar increases in renal vasoconstriction in HF (n = 4). Greater reductions in RBV were found in HF than in controls during the early phases of exercise. This effect was not likely due to a metaboreflex or central command. Thus our data suggest that muscle mechanoreflex activity is enhanced in HF and serves to vigorously vasoconstrict the kidney. We believe this compensatory mechanism helps preserve blood flow to exercising muscle in HF.