Correlation Between Cardiac Output and Cerebral Blood Flow, Brain Atrophy in Normal Aging

一般认为无血压变化的心输出量变化与正常人脑血流量调节无关。然而，我们经常遇到有过一过性心律失常或心动过缓的老年患者表现为精神恶化而血压没有下降。这表明心输出量的减少明显参与脑血流的调节，而不依赖于血压的变化。心输出量与脑血流量、脑功能的相关性研究较少。我们研究了正常衰老过程中心输出量与脑功能、形态学变化的相关性。(1)正常老年人局部脑血流（rCBF）与脑萎缩的关系：25例正常老年人（平均75.4岁）。方法：采用133Xe吸入法测定rCBF。采用无创再呼吸法测量心输出量。我们用QC/BSA作为指标…更多的是心输出量。采用0.15T MRI进行核磁共振成像，计算脑萎缩指数（BAI）。结果：1)平均rCBF与心输出量无相关性（r=0.28）。2)脑血管阻力（CVR）与心输出量显著相关（r=-0.42,p<0.05）。3) BAI与心输出量无相关性。(2)正常成人rCBF与心理功能的关系：48例正常成人（平均60岁）。方法：采用Okabe智力测验（日本老年人韦氏记忆量表的简化修正版）对语言智力进行评价。采用柯氏块测验评估表演智力。心输出量和rCBF测量方法相同。结果：1)心输出量与年龄显著相关（r=-0.319, p<0.05）。2)心输出量与平均rCBF （r=-0.319, p<0.05）、CVR （r=-0.32, p<0.05）显著相关。3)言语智力与心输出量也显著相关（r=0.316, p<0.05）。3)心室周围高强度（PVH） MRI与事件相关电位P300的关系。受试者：92名正常成人（平均56.5岁）。方法：采用MRI 0 ~ IV级评价PVH。P300潜伏期在Cz上通过使用两种不同的纯声音的奇数球刺激来测量。结果：1)年龄与PVH、P300潜伏期存在显著相关。2)心输出量与PVH等级和P300潜伏期无相关性。3)血压与心输出量无相关性。结论：正常老年人和成人心输出量与CVR有显著相关性。提示心输出量是调节CVR的重要因素。此外，正常成人的平均rCBF和语言智力与心输出量相关。上述结果提示心输出量是调节脑血流的重要因素之一，并在一定程度上参与了衰老过程中心理功能的恶化。少

It is generally believed that changes in cardiac output without blood pressure changes is indifferent to regulation of cerebral blood flow in normal subjects. However, we often experienced that aged patient who had transient arrythmia or bradycardia showed mental deterioration without decrease in blood pressure. This fact suggests that decrease in cardiac output significantly participates on regulation of cerebral blood flow independent with the changes in blood pressure. There are few reports studied the correlation between cardiac output and cerebral blood flow, brain function. We investigated the correlation between cardiac output and brain function, morphorogical changes in normal aging.(1) Relation to regional Cerebral Blood Flow (rCBF) and brain atrophy in normal aged Subjects : Twenty-five normal elderly people (mean 75.4 years). Methods : The rCBF was measured using 133Xe inhalation method. Cardiac output was measured by non-invasive re-breathing method. We used QC/BSA as index … More of an cardiac output. Magnetic resonance imaging was performed by 0.15T MRI and brain atrophy index (BAI) was calculated on MRI film. Results : 1) The mean rCBF did not correlate to cardiac output (r=0.28). 2) Cerebro-Vascular Resistance (CVR) significantly correlated to cardiac output (r=-0.42,p<0.05). 3) The BAI did not correlate to cardiac output.(2) Relation to rCBF and mental function in normal adults Subjects : Forty-eight normal adults (mean 60 years). Methods : Verbal intelligence was evaluated by Okabe's mental test (shortened and modified version of Wechsler Memory Scale for Japanese aged). Performance intelligence was evaluated by Ko' Block Test. Cardiac output and rCBF were measured by the same methods. Results : 1) The cardiac output significantly correlated to age (r=-0.319, p<0.05). 2) Cardiac output significantly correlated to mean rCBF (r=-0.319, p<0.05) and CVR (r=-0.32, p<0.05). 3) Verbal intelligence also significantly correlated with cardiac output (r=0.316, p<0.05).3) Relation to Peri-Ventricular High intensity (PVH) on MRI and event related potential P300 Subjects : Ninety-two normal adults (mean 56.5 years). Methods : PVH was evaluated by grading from 0 to IV on MRI. P300 latency was measured on Cz by odd ball stimuli using two different pure sounds. Results : 1) There were significant correlations between age and PVH, between age and P300 latency. 2) Cardiac output did not correlate to grade of PVH and P300 latency. 3) There was no correlation between blood pressure and cardiac output. Conclusion : Cardiac output significantly correlated with CVR in normal aged subjects and adults. This result indicates that cardiac output is important factor to regulate CVR. Moreover, mean rCBF and verebal intelligence correlated with cardiac output in normal adults. These results suggests that cardiac output is one of the important factor to regulate CBF and it participates in some extent to deteriorate of mental function in aging. Less