Purewal T S, Goss D E, Zanone M M, Edmonds M E, Watkins P J
Department of Diabetes, Kings College Hospital, Denmark Hill, London, UK.
Diabet Med. 1995 Jun;12(6):513-22. doi: 10.1111/j.1464-5491.1995.tb00534.x.
Postural hypotension results from sympathetic failure to cause superior peripheral vasoconstriction. The importance of the splanchnic circulation was studied by measuring mesenteric artery blood flow with duplex Doppler scanning. Nine normal and 9 Type 1 diabetic controls were compared to 8 Type 1 patients with autonomic neuropathy whose pressure fell 40-113 mmHg (range) on tilting. Measurements were made supine and after vertical tilt, fasting without insulin and after a 550 kcal meal. Superior mesenteric artery diameter decreased on tilting in normal controls but not in diabetic control or neuropathy groups (supine vs tilted: controls. 6.3 +/- 0.9 to 5 +/- 0.9 mm, p = 0.004, diabetic controls: 6.0 +/- 0.6 to 6.0 +/- 1.0 mm, and neuropathy group: 6.4 +/- 0.9 to 5.6 +/- 0.9 mm), but proportional blood flow changes were similar in all subjects (controls: 407 +/- 154 to 255 +/- 67 ml min-1 (-31%, p = 0.03), diabetic controls: 379 +/- 140 to 306 +/- 149 ml min-1 (-8%, p = 0.28), neuropathy group: 639 +/- 371 to 435 +/- 142 ml min-1 (-23%, p = 0.10). Postprandially supine superior mesenteric artery flow increased in all subjects but this did not affect the degree of systolic blood pressure drop on tilting (fasting vs postprandial blood flow: controls: 407 +/- 154 to 775 +/- 400 ml min-1 (p = 0.04), diabetic controls: 379 +/- 140 to 691 +/- 262 ml min-1 (p = 0.01), neuropathy group: 639 +/- 371 to 943 +/- 468 ml min-1 (p < 0.06)). The similarity of superior mesenteric artery responses to tilting in the three groups, and the lack of exacerbation of postural hypotension in the presence of postprandial hyperaemia indicates that control of splanchnic blood flow is less important in the aetiology of diabetic autonomic postural hypotension than previously thought.
体位性低血压是由交感神经无法引起外周血管收缩所致。通过双功多普勒扫描测量肠系膜动脉血流量，研究了内脏循环的重要性。将9名正常人和9名1型糖尿病对照者与8名1型自主神经病变患者进行比较，这些患者在倾斜时血压下降40 - 113 mmHg（范围）。测量在仰卧位、垂直倾斜后、空腹未使用胰岛素时以及进食550千卡餐食之后进行。正常对照组倾斜时肠系膜上动脉直径减小，而糖尿病对照组和神经病变组则不然（仰卧位与倾斜位相比：对照组，6.3±0.9至5±0.9毫米，p = 0.004；糖尿病对照组，6.0±0.6至6.0±1.0毫米；神经病变组，6.4±0.9至5.6±0.9毫米），但所有受试者的血流比例变化相似（对照组：407±154至255±67毫升/分钟（-31%，p = 0.03）；糖尿病对照组：379±140至306±149毫升/分钟（-8%，p = 0.28）；神经病变组：639±371至435±142毫升/分钟（-23%，p = 0.10）。餐后仰卧位时，所有受试者的肠系膜上动脉血流量均增加，但这并未影响倾斜时收缩压下降的程度（空腹与餐后血流量相比：对照组：407±154至775±400毫升/分钟（p = 0.04）；糖尿病对照组：379±140至691±262毫升/分钟（p = 0.01）；神经病变组：639±371至943±468毫升/分钟（p < 0.06））。三组中肠系膜上动脉对倾斜的反应相似，且餐后充血时体位性低血压并未加重，这表明在内脏血流控制在糖尿病自主神经体位性低血压病因中的重要性低于先前的认识。
