Marchant B, Umachandran V, Stevenson R, Kopelman P G, Timmis A D
Department of Cardiology, London Chest Hospital, United Kingdom.
J Am Coll Cardiol. 1993 Nov 1;22(5):1433-7. doi: 10.1016/0735-1097(93)90554-e.
Silent myocardial ischemia is common in patients with diabetes. This study was designed to assess the role of subclinical autonomic impairment in diabetic patients with silent ischemia.
Studies have suggested that silent ischemia is more common in diabetic patients with microvascular complications, but this has not been a consistent finding.
Twenty-two diabetic and 30 nondiabetic patients with proved coronary artery disease and a history of angina and ischemia on treadmill stress testing underwent clinical tests of autonomic function and measurement of 24-h heart rate variability. Diabetic patients with a history of microvascular complications were excluded.
Although all 52 patients manifested ischemia during treadmill testing, only 36 patients experienced angina (angina group), whereas 16 did not (silent ischemia group). Diabetic and nondiabetic patients were similar in age (59 +/- 1 vs. 61 +/- 2 years, p = 0.56) and extent of coronary artery disease. However, clinical tests showed reduced parasympathetic function in the diabetic patients (Valsalva ratio 1.38 +/- 0.07 vs. 1.60 +/- 0.06; p = 0.007). Patients in the silent ischemia group were more often diabetic (33% vs. 63%, p = 0.05) and had prolonged time to ischemia on treadmill testing (200 +/- 20 vs. 271 +/- 20 s, p = 0.03). In addition, autonomic function was impaired in the silent group (supine/standing heart rate ratio 1.15 +/- 0.02 vs. 1.05 +/- 0.02, p = 0.002). Subgroup analysis showed that abnormalities of autonomic function were confined to the diabetic patients in the silent group.
Despite the absence of overt microvascular complications, diabetic patients with silent exertional ischemia have evidence of significant autonomic impairment compared with findings in symptomatic patients. This difference is not seen in nondiabetic patients and indicates that subclinical neuropathy is an important cause of silent ischemia in patients with diabetes.
无症状性心肌缺血在糖尿病患者中很常见。本研究旨在评估亚临床自主神经功能损害在糖尿病无症状性缺血患者中的作用。
研究表明，无症状性缺血在患有微血管并发症的糖尿病患者中更为常见，但这并非一直是一致的发现。
22例糖尿病患者和30例非糖尿病患者，均经证实患有冠状动脉疾病，有心绞痛病史且平板运动试验显示有缺血，接受了自主神经功能的临床测试和24小时心率变异性测量。排除有微血管并发症病史的糖尿病患者。
尽管所有52例患者在平板试验中均表现出缺血，但只有36例患者经历过心绞痛（心绞痛组），而16例未经历过（无症状性缺血组）。糖尿病患者和非糖尿病患者在年龄（59±1岁对61±2岁，p = 0.56）和冠状动脉疾病程度方面相似。然而，临床测试显示糖尿病患者的副交感神经功能降低（乏氏动作比率1.38±0.07对1.60±0.06；p = 0.007）。无症状性缺血组的患者糖尿病患者比例更高（33%对63%，p = 0.05），且平板试验中出现缺血的时间更长（200±20秒对271±20秒，p = 0.03）。此外，无症状组的自主神经功能受损（仰卧/站立心率比率1.15±0.02对1.05±0.02，p = 0.002）。亚组分析显示，自主神经功能异常仅限于无症状组中的糖尿病患者。
尽管没有明显的微血管并发症，但与有症状的患者相比，患有无症状性运动性缺血的糖尿病患者有明显的自主神经功能损害证据。在非糖尿病患者中未发现这种差异，这表明亚临床神经病变是糖尿病患者无症状性缺血的重要原因。
