Changes in Peripheral Blood Pressures after Five Years of Follow-up in Non-operated Patients with Intermittent Claudication

ABSTRACT Changes in the segmental blood pressures (BP) in the legs after five years of follow-up and factors related to the changes were studied in 93 non-operated non-diabetic patients with intermittent claudication. Independent variables affecting the ankle/arm BP index (ABI) in the more affected leg were the initial ABI, smoking, duration of claudication and location of the stenoses (whether single or multiple). ABI was stable in non-smokers but decreased in smokers. It also decreased in patients with multiple stenoses at the initial examination but not in those with single stenoses. The correlation between subjective changes in claudication and changes in the ankle BP was poor. In the less affected leg, ABI decreased both in smokers and non-smokers but stenoses in legs without signs of stenoses initially developed to a greater extent in smokers than in non-smokers. Smoking is an important risk factor for progression of the occlusive atherosclerotic disease in intermittent claudication. Patients with multiple stenoses seem to have a more progressive occlusive disease.     

Cessation of Smoking in Patients with Intermittent Claudication

ABSTRACT The effects of cessation of smoking were studied in 343 patients with intermittent claudication. One year after the initial examination 39 (11%) had stopped smoking and 304 (89%) continued to smoke. The outcome in these two groups was compared. They were comparable regarding baseline characteristics. Rest pain did not develop in any of the non-smokers. In smokers the cumulative proportion with rest pain was 16% after seven years (p<0.05). The cumulative proportions with myocardial infarctions after 10 years were 11 and 53%; the cumulative rates of cardiac deaths 6 and 43%; and the 10-year survival 82 and 46% among non-smokers and smokers, respectively. In multivariate Cox regression analyses the association between smoking and infarction (p<0.05) and cardiac death (p<0.05) was significant. The survival curves deviated and when they were compared after one year's follow-up the association between smoking and mortality was significant (p<0.05). The findings provide further evidence for the fact that it is of utmost importance that patients with intermittent claudication stop smoking.     

The Influence of Hypertension on Microvascular Blood Flow and Resistance to Flow in the Skin of Patients with Type 2 (Non-insulin-dependent) Diabetes

Maximum microvascular blood flow and resistance to flow were determined in the skin of nine hypertensive and nine normotensive Type 2 (non-insulin-dependent) diabetic patients and nine control subjects to determine the influence of hypertension on these variables. Maximum blood flow was reduced in both the hypertensive (1.05 (0.70–1.42) V) and normotensive (1.04 (0.79–1.63) V) Type 2 diabetic patients when compared with control subjects (1.40 (1.26–2.13) V, p < 0.01 for hypertensive and p < 0.05 for normotensive patients, respectively); however, maximum blood flow was similar in both groups of diabetic patients (p = 0.82). In contrast, resistance to flow was significantly greater in the diabetic patients with hypertension (127.2 (87.5–181.3) mmHg V^?1 vs 84.7 (61.9–123.0) mmHg V^?1 normotensive diabetic patients, p < 0.02). In addition, R was greater in the normotensive Type 2 diabetic patients than in control subjects (70.7 (44.7–79.9) mmHg V^?1, p < 0.05). These results suggest that hypertension is associated with an additional rise in pre-capillary vascular resistance in Type 2 diabetes which, while protecting the microcirculation from the effects of increased arterial pressure, may further diminish protective hyperaemic responses.     

Diabetes Mellitus and Intermittent Claudication: Relation between Peripheral Vascular Complications and Location of the Occlusive Atherosclerosis in the Legs

ABSTRACT. Forty-seven diabetic patients with intermittent claudication without rest pain or gangrene at the initial examination were followed up over a six-year period. They were compared with 224 non-diabetic patients with intermittent claudication. The cumulative proportions of patients with gangrene were 31 % in the diabetic group and 5% in the control group (p < 0.001). The corresponding figures for rest pain and/or gangrene were 40 and 18%, respectively (p < 0.001). The frequency of aorto-iliac and multiple stenoses was higher among diabetic patients who developed peripheral vascular complications (rest pain, gangrene) than in the control group. The frequency of multiple stenoses was also higher in the former subgroup than in diabetics without such complications. In conclusion, the degree of involvement of the large vessels in occlusive arterial disease influences the risk of development of peripheral vascular complications in diabetic patients with intermittent claudication.     

Exercise Rehabilitation Improves Functional Outcomes and Peripheral Circulation in Patients with Intermittent Claudication: A Randomized Controlled Trial

OBJECTIVE: To determine the effects of a 6-month exercise program on ambulatory function, free-living daily physical activity, peripheral circulation, and health-related quality of life (QOL) in disabled older patients with intermittent claudication. DESIGN: Prospective, randomized controlled trial. SETTING: University Medical (Center and Veterans Affairs Medical Center, Baltimore, Maryland. PARTICIPANTS: Thirty-one of 61 patients with Fontaine stage II peripheral arterial occlusive disease (PAOD) were randomized to exercise rehabilitation and 30 to usual-care control. Three patients from the exercise group and six patients from the control group dropped out, leaving 28 and 24 patients, respectively, completing the study in each group. INTERVENTION: Six months of exercise rehabilitation. MEASUREMENTS: Treadmill distance walked to onset of claudication and to maximal claudication, ambulatory function, peripheral circulation, perceived QOL, and daily physical activity. RESULTS: Compliance with the exercise program was 73% of the possible sessions. Exercise rehabilitation increased treadmill distance walked to onset of claudication by 134% (P < .001) and to maximal claudication by 77% (P < .001), walking economy by 12% (P = .003), 6-minute walk distance by 12% (P < .001), and maximal calf blood flow by 30% (P < .001). Changes in distance walked to maximal pain correlated with changes in walking economy (r = -.50, P = .013) and changes in maximal calf blood flow (r = .38, P = .047). Exercise rehabilitation increased accelerometer-derived daily physical activity by 38% (P < .001); this change correlated with the change in distance walked to maximal pain (r = .45, P = .020). These improvements were significantly better than the changes in the control group (P < .05). CONCLUSION: Improvements in claudication following exercise rehabilitation in older PAOD patients are dependent on improvements in peripheral circulation and walking economy. Improvement in treadmill claudication distances in these patients translated into increased accelerometer-derived physical activity in the community, which enabled the patients to become more functionally independent.     

Resistance to Blood Flow in Nonuniform Capillaries

Objective : Microvessels in living tissues are not uniform cylinders, and red blood cells (RBCs) are continually deformed when traversing them. This may contribute to higher resistance to blood flow observed in microvessels compared with that in corresponding uniform glass tubes. Here, a theoretical model was used to estimate flow resistance in nonuniform capillaries and its dependence on hematocrit, flow rate, and mechanical properties of RBCs. Methods : Single-file motion of RBCs through capillaries with sinusoidally varying cross-sections was simulated, assuming axisymmetrical geometry. Effects of cell membrane shear viscosity and elasticity were included. Lubrication theory was used to describe the plasma flow. Results : Predicted resistance to blood flow in capillaries with variable cross-sections was substantially higher than in uniform vessels with the same mean diameters. Resistance depended on vessel geometry, flow rate, and hematocrit. At tube hematocrit 30%, the increase in resistance was 40%–58% when diameter varied between 4.5 and 6 μm with wavelength 20 μm and 58%–77% for variations between 4 and 5 μm with wavelength 10 μm. Larger relative increases in resistance were predicted for RBCs with increased membrane shear viscosity. Conclusions : Effects of transient RBC deformations in irregular capillaries contribute significantly to blood flow resistance in capillaries. However, this effect is not sufficient to account for the flow resistance observed in living tissues.     

2型糖尿病患者外周血内皮祖细胞数量和功能的变化

目的观察2型糖尿病（DM）患者外周血内皮祖细胞（EPCs）数量和功能的改变。方法选择2型DM患者16例和对照组19例，密度梯度离心法收集外周血单个核细胞（MNCs），诱导分化培养7d后，荧光染色和流式细胞术分别鉴定贴壁细胞为EPCs。采用二苯基四氮唑嗅盐（MTT）比色法、黏附能力测定实验和体外血管生成实验检测EPCs的增殖能力、黏附能力和体外血管生成能力。结果2型DM患者外周血EPCs数量明显减少[（3．1±1．2）×10^5]：[（3．9±1．1）×10^5]，P〈0．05。且2型DM患者外周血EPCs黏附能力[（50±15）：（60±11）细膨×200视野，P〈0．05]，增殖能力[（0．170±0．056）：（0．225±0．071）OD值，P〈0．05]，体外血管生成能力均明显受损。结论2型DM患者外周血EPCs的数量减少，且其增殖、黏附和血管生成能力受损。     

Gait Alterations Associated with Walking Impairment in People with Peripheral Arterial Disease with and without Intermittent Claudication

OBJECTIVES: To describe gait alterations associated with impaired walking endurance in patients with and without lower-extremity peripheral arterial disease (PAD) and determine whether the Caltrac accelerometer provides a valid measure of physical activity in PAD. DESIGN: Cross-sectional. SETTING: Academic medical center. PARTICIPANTS: PAD (n = 40) and non-PAD patients (n = 22) from two Chicago hospitals. MEASUREMENTS: Participants underwent measurement of the ankle brachial index (ABI), leg length, and 6-minute walk. Steps per minute and step length were measured during the first and last 100 feet of the 6-minute walk. Participants wore a Caltrac accelerometer, sensitive to vertical acceleration, during the 6-minute walk and for 7 continuous days. RESULTS: Five PAD participants (13%) and one non-PAD participant (5%) ceased walking before the end of 6 minutes. Among the remaining participants, distance walked in 6 minutes was more highly related to walking velocity during the last 100 feet of the walk than walking velocity during the first 100 feet. ABI was associated significantly with cadence (20.77 steps/minute per unit ABI, P <.001) but not step length (10.12 centimeters/unit ABI, P =.08). ABI was associated significantly with 6-minute walk distance (493 feet/unit ABI, P =.018), but this association disappeared completely after adjustment for step length and cadence. We found no difference in accelerometer scores between PAD and non-PAD participants over a fixed distance of 800 feet (7.34 vs 7.17 activity units, P =.789). However, scores were significantly different after 7 days (730.8 vs 1,485.0 activity units, P =.003). CONCLUSION: Walking performance in PAD patients who completed 6 minutes of walking was largely determined by a decline in walking velocity rather than slower initial walking velocity. ABI was more closely associated with cadence than step length. Future studies should assess the effect of exercise programs and revascularization on cadence and step length in PAD.     

二甲双胍治疗2型糖尿病人对血压影响的研究

目的观察胰岛素增敏剂二甲双胍治疗2型糖尿病,降低血浆胰岛素水平、改善胰岛素敏感性后对血压的影响.方法 71例2型糖尿病人口服二甲双胍(格华止)850 mg,qd～bid.治疗前后测定BMI、血压、FBG、PBG、FINS、PINS,并按HOMA模型计算胰岛素抵抗指数和胰岛素分泌指数.结果 (1) 二甲双胍治疗8周后,BMI治疗前后比较无显著性差异;血压治疗后明显下降,降压幅度达 13.1±4.9/4.2±9.9 mmHg, 血压治疗前后比较有显著性差异;(2)治疗后FBG、PBG、FINS均明显下降,治疗前后比较有显著性差异;(3)治疗后HOMA-IR下降,IAI升高,治疗前后比较有显著性差异,但HOMA-IS、FINS/FBG无显著性差异.结论二甲双胍治疗2型糖尿病,在降低血浆胰岛素水平、改善IR的同时,伴有血压的明显下降.     

Postprandial Improvement of Gastric Dysrhythmias in Patients with Type II Diabetes

Using the technique known as electrogastrography, we studied the postprandial response of gastric myoelectrial activity in subjects with type II diabetes. Seventy-one subjects with type II diabetes underwent 1 hr of fasting electrogastrography recording. HbA1c and fasting serum glucose levels were obtained. Subjects then underwent an additional 2 hr of electrogastrography recording in the post prandial state. Sixty of the 71 patients (85%) had gastric rhythm abnormalities in the fasting state. Forty-six of 71 subjects (65%) responded to the test meal by improving their electrogastrography tracings (responders) while 35% did not respond (nonresponders). The time spent in bradygastria during the fasting state by responders was 26.3 ± 12.8% vs 10.9 ± 8.5% for nonresponders (P < 0.0001). The percent tachygastria during the fasting state in responders was 19.8 ± 13.0%, which was less than nonresponders (38.3 ± 29.7%) (P < 0.001). Fasting plasma glucose and HbA1c could not be used to predict the gastric myoelectrical response to meal. In conclusion, gastric rhythm disturbances are common in type II diabetes; there was no correlation between HbA1c levels, age, duration of diabetes, or fasting serum glucose and gastric dysrhythmia in response to meal; two groups of subjects emerged: those who became less dysrhythmic in the post pradial state (responders) and those who did not (non-responders); and fasting bradygastria was associated with responders and fasting tachygastria was associated with nonresponders.     

社区老年高血压合并2型糖尿病病人餐后血糖和血压的关系探讨

目的分析社区老年高血压合并2型糖尿病患者餐后血糖和血压间的关系。方法选取老年高血压合并2型糖尿病患者45例、单纯高血压患者45例及体检健康者40名,比较3组受试者血糖及血压。结果高血压合并糖尿病患者FPG、2 h PG、FINS、Hb Al C均明显高于单纯高血压组与健康者(P0.05),日间平均收缩压、日间平均舒张压、日间平均脉压、夜间平均收缩压、夜间平均舒张压、夜间平均脉压及非杓型动态血压节律占比均显著高于单纯高血压患者。结论社区老年高血压合并2型糖尿病患者餐后血糖和血压昼夜节律异常、患者脉压等密切相关。     

Seasonal Variation in Blood Pressure in 162,135 Patients With Type 1 or Type 2 Diabetes Mellitus

Seasonal variation in blood pressure (BP) has been observed in different populations. However, only few studies have focused on BP seasonality in diabetic patients. This study examined the seasonal patterns in BP in 62,589 patients with type 1 diabetes mellitus (T1DM) and in 99,546 patients with type 2 diabetes mellitus (T2DM) from the German/Austrian Diabetes Follow‐up Registry. Adjusted mean BP values revealed seasonal cycles of 12 months, with higher BP in colder months. Using harmonic regression models, the estimated systolic BP difference throughout the year was 2.28/2.48 mm Hg in T1DM/T2DM (both P<.001). Interestingly, seasonal variation in diastolic BP was larger in T1DM than in T2DM (1.24/0.64 mm Hg, P<.001). A sex difference was observed in T1DM only, while age differences occurred in both types of diabetes. Correlations between BP and potentially related factors such as outdoor temperature indicated that reasons underlying BP seasonality are likely to be complex and vary by subgroup.     

Insulin Resistance with Respect to Lipolysis in Non-diabetic Relatives of European Patients with Type 2 Diabetes

Type 2 diabetes is characterized by resistance to insulin action of glucose metabolism and lipolysis. First-degree relatives of diabetic patients are at increased risk of developing diabetes themselves and early metabolic abnormalities in these relatives may represent primary defects in the pathogenesis of diabetes. Our previous work has demonstrated impaired suppression of lipolysis after an oral glucose load in glucose-tolerant relatives of Asian origin, but not in European relatives. To investigate whether a more subtle defect exists in the European population we studied 8 first-degree relatives of European patients and 9 matched control subjects. All had normal glucose tolerance. Glycerol and glucose turnovers were measured using a primed constant infusion of the stable isotopic tracers [1, 1, 1, 2, 3²H₅] glycerol and [6, 6²H] glucose, basally and in response to a very low dose insulin infusion (0.005 units kg^-1 h^-1). The relatives had higher basal insulin concentrations (median (range): 49 (30 to 113) vs 28 (18 to 66) pmol 1^-1, p < 0.05) compared to controls, but basal glycerol and glucose turnovers and plasma concentrations of glycerol, glucose, and non-esterifed fatty acids (NEFA) were similar. Following insulin, the suppression of glycerol appearance in the circulation measured isotopically was significantly less complete in the relatives compared with controls (mean change ± SEM: + 0.06 ± 0.21 vs -0.51 ± 0.16 μmol kg^-1 min^-1, p < 0.05). Plasma glycerol concentration decreased to a similar extent in relatives and controls, as did glucose and NEFA levels (mean change ± SEM: glycerol -12 ± 3 vs -8 ± 4 μmol 1^-1; glucose -0.37 ± 0.06 vs -0.30 ± 0.10 mmol.l^-1; NEFA -152 ± 48 vs -130 ± 32 μmol.1^-1). The change in glucose turnover was not different in relatives and controls (change -0.10 ± 0.03 vs -0.07 ± 0.06 mg kg^-1 min^-1). We conclude that glucose-tolerant relatives of European origin exhibit subtle defects in insulin sensitivity with respect to lipolysis.