Poredos P, Orehek M, Tratnik E
University Medical Centre, Department of Angiology, Ljubljana, Slovenia.
Angiology. 1999 Mar;50(3):201-8. doi: 10.1177/000331979905000304.
Cigarette smoking is firmly established as a risk factor for atherosclerosis. However, the exact mechanism causing smoking-related damage to the arterial wall and its relation to the atherosclerotic process is not known. Also unknown is the time delay between the start of smoking and the sequence of functional and morphologic changes occurring in the arterial wall caused by smoking and their interrelationship. Therefore, the aim of this study was to evaluate the acute and chronic effects of smoking on endothelium-dependent (flow-mediated) dilation (FMD) of the peripheral arteries, the effects of dose and duration of chronic smoking on intima-media thickness (IMT) of the carotid arteries, and their interrelationship. The study encompassed two groups of smokers. In group A there were 40 subjects of both sexes, who smoked on average 17.6 +/- 6.5 cigarettes per day, for 5 to 15 years (mean 8.95 +/- 4.0 years), mean age 28.1 years. Group B consisted of 42 smokers of both sexes who smoked 21.15 +/- 8.2 cigarettes/day for more than 15 years (mean 21.15 +/- 3.4 years), mean age 39.5 years. The control group consisted of 40 healthy subjects without major risk factors of atherosclerosis, mean age 29.1 years. By means of high-resolution ultrasound the brachial artery diameter was measured at rest and during reactive hyperemia (after release of a forearm tourniquet) and the flow-mediated, endothelium-dependent dilation was calculated. The IMT of the carotid arteries was determined in all subjects by use of B-mode ultrasonography. Resting blood flow in the brachial arteries was significantly less in the smokers' groups than in controls (78.8 +/- 31.9 vs 134.9 +/- 45.0 mL/min, p<0.0001). This decrease was much more evident in female than in male smokers. Female smokers also had significantly smaller brachial artery diameter at rest. In smokers the FMD of the brachial artery was reduced (11 +/- 4% vs 7 +/- 4%, p<0.004) and the mean IMT was significantly greater than in controls (0.68 +/- 0.13 vs 0.59 +/- 0.04 mm, p<0.001). Impairments of FMD and IMT increase were related to the duration and to the number of cigarettes smoked. In all subjects IMT was significantly correlated with total and LDL cholesterol, fibrinogen, lipoprotein(a) concentration, body mass index, and age of the subjects, but multivariate analysis showed that only total dose smoked and fibrinogen concentration were independently related to IMT. The results of this study show that smoking is associated with dose-related impairment of FMD and increased IMT of the carotid arteries. Impairment of FMD occurs in smokers very early and is the earliest detectable event, preceding morphologic changes of the vessel wall. Some harmful effects of smoking on the vessel wall are gender related.
吸烟已被确认为动脉粥样硬化的一个危险因素。然而，吸烟导致动脉壁损伤的确切机制及其与动脉粥样硬化进程的关系尚不清楚。吸烟开始与吸烟引起的动脉壁功能和形态学变化序列及其相互关系之间的时间延迟也不清楚。因此，本研究的目的是评估吸烟对周围动脉内皮依赖性（血流介导）舒张（FMD）的急性和慢性影响、慢性吸烟的剂量和持续时间对颈动脉内膜中层厚度（IMT）的影响及其相互关系。该研究包括两组吸烟者。A组有40名男女受试者，平均每天吸烟17.6±6.5支，持续5至15年（平均8.95±4.0年），平均年龄28.1岁。B组由42名男女吸烟者组成，他们每天吸烟21.15±8.2支，超过15年（平均21.15±3.4年），平均年龄39.5岁。对照组由40名无动脉粥样硬化主要危险因素的健康受试者组成，平均年龄29.1岁。通过高分辨率超声在静息状态和反应性充血期间（松开前臂止血带后）测量肱动脉直径，并计算血流介导的内皮依赖性舒张。所有受试者均通过B型超声检查测定颈动脉的IMT。吸烟者组肱动脉的静息血流量明显低于对照组（78.8±31.9 vs 134.9±45.0 mL/min，p<0.0001）。这种减少在女性吸烟者中比男性吸烟者中更为明显。女性吸烟者静息时肱动脉直径也明显较小。吸烟者肱动脉的FMD降低（11±4% vs 7±4%，p<0.004），平均IMT明显大于对照组（0.68±0.13 vs 0.59±0.04 mm，p<0.001）。FMD受损和IMT增加与吸烟持续时间和吸烟量有关。在所有受试者中，IMT与总胆固醇、低密度脂蛋白胆固醇、纤维蛋白原、脂蛋白（a）浓度、体重指数和受试者年龄显著相关，但多变量分析表明，只有吸烟总量和纤维蛋白原浓度与IMT独立相关。本研究结果表明，吸烟与FMD的剂量相关损害和颈动脉IMT增加有关。吸烟者中FMD受损很早就会出现，是最早可检测到的事件，早于血管壁的形态学变化。吸烟对血管壁的一些有害影响与性别有关。
