Curvature and tortuosity of the superficial femoral artery: a possible risk factor for peripheral arterial disease.

Atherosclerosis in the superficial femoral artery (SFA) resulting in peripheral arterial disease is more common in men than women and shows a predilection for the region of the adductor canal. Blood flow patterns are related to development of atherosclerosis, and we investigated if curvature and tortuosity of the femoral artery differed between young men and women and if differences resulted in adverse flow patterns. Magnetic resonance imaging (MRI) and computational fluid dynamics (CFD) were combined in 18 young adult volunteers (9 men) to assess the relationship of flow features to likely sites of future atherosclerosis formation. Subjects underwent MRI of the right SFA, three-dimensional vascular geometry was reconstructed, and measures of tortuosity and curvature were calculated. Tortuosity and curvature were significantly greater for men than women, and this was related to increased body surface area, body mass index, or weight in men. In both sexes, "tortuosity" increased from the midthigh to the popliteal fossa. The greatest curvature was found within the distal quarter of the SFA. CFD modeling was undertaken on MRI-based reconstructions of the SFA. Wall shear stresses (WSS) were extracted from the computations. WSS showed greater spatial variation in the men than in the women, and the men exhibited lower mean WSS. These data indicate that sex differences related to body size and anatomical course of the femoral artery may contribute to the enhanced risk of focal atherosclerosis in the adductor canal.

Relationship between corrected TIMI frame counts at three weeks and late survival after myocardial infarction.

OBJECTIVES: To evaluate the corrected Thrombolysis in Myocardial Infarction (TIMI) frame count (CTFC) as a predictor of late survival after myocardial infarction. BACKGROUND: Thrombolysis in Myocardial Infarction flow grades predict late survival after myocardial infarction. The CTFC provides a more reproducible measurement of infarct-related artery blood flow than the TIMI flow grade, and has been linked to 30-day outcomes, but it has not yet been established how the CTFC correlates with late survival. METHODS: Of 1,001 patients with acute myocardial infarction presenting within 4 h of symptom onset, 882 underwent angiography at approximately three weeks. Infarct artery flow was assessed, blinded to clinical outcomes, according to the CTFC and TIMI flow grade. Late cardiac mortality and survival were determined in 97.5% of patients. RESULTS: The mean CTFC was 40 +/- 29 in 644 patent infarct arteries (median, 34 [interquartile range, 24 to 47]). The CTFC, assessed as a continuous univariate variable, was found to be a predictor of five-year survival, as was the TIMI flow grade (both p < 0.001). On multivariate analysis, factors associated with five-year survival included the ejection fraction or end-systolic volume index (both p < 0.001); exercise duration (p = 0.005), age (p = 0.008), diabetes (p = 0.02) and CTFC (p = 0.02) or TIMI flow (p = 0.02). The same factors, except for the CTFC and TIMI flow grade, were predictors of 10-year survival. CONCLUSIONS: The CTFC three weeks after myocardial infarction was an independent predictor of five-year survival, but not 10-year survival. Although the CTFC provided additional prognostic information within TIMI flow grades, its superiority was not demonstrated.

Injection related anxiety in insulin-treated diabetes.

The presence of injection related anxiety and phobia may influence compliance, glycaemic control and quality of life in patients with insulin-treated diabetes. Unselected consecutive, insulin-treated patients attending a diabetes clinic for follow-up, completed a standardised questionnaire providing an injection anxiety score (IAS) and general anxiety score (GAS). A total of 115 insulin-treated (80 Type 1 and 35 Type 2) diabetic patients completed the questionnaire. Injections had been avoided secondary to anxiety in 14% of cases and 42% expressed concern at having to inject more frequently. An IAS > or = 3 was seen in 28% of patients and of these, 66% injected insulin one to two times/day, 45% had avoided injections, and 70% would be bothered by more frequent injections. A significant correlation between IAS and GAS was seen (Kendall's tau-a 0.30, 95% CI 0.19-0.41, P < 0.001). GAS was significantly associated with both previous injection avoidance and expressed concern at increased injection frequency. No significant correlation was seen with HbA1c and injection or general anxiety scores. Symptoms relating to insulin injection anxiety and phobia have a high prevalence in an unselected group of diabetic patients requiring insulin injections and are associated with higher levels of general anxiety.

Local and regional wave speed in the aorta: effects of arterial occlusion.

Arterial wave speed is widely used to determine arterial distensibility and has been utilised as a surrogate marker for vascular disease. A comparison between the results of the traditional foot-to-foot method for measuring wave speed to those of the pressure-velocity loop (PU-loop) method is one of the primary objectives of this paper. We also investigate the regional wave speed along the aorta, and the effect of arterial occlusion on the PU-loop measured in the ascending aorta. In 11 anaesthetised dogs, a total occlusion lasting 3 min was produced at four sites: upper thoracic, diaphragm, abdominal and left iliac artery. Pressure and flow in the ascending aorta and pressure proximal to the occlusion site were measured, and data were collected before, during the occlusion and after the occlusion had been removed. In control conditions, the wave speeds determined by the PU-loop in the aortic root were systematically lower than those measured by the foot-to-foot method. During thoracic and diaphragm occlusions, mean aortic pressure and wave speed increased significantly but returned to control values after each occlusion had been removed. The PU-loop is an objective and easy to use method for determining wave speed and can be advantageous for use in short arterial segments when local measurements of pressure and velocity are available.

The roles for coronary surgery and angioplasty in the management of patients with stable angina: evidence and decision making.

Evidence from the randomized studies of coronary surgery suggests that patients who benefit from surgery in terms of improved survival are those with left main stem stenosis, triple vessel coronary artery disease, impaired left ventricular function or higher angina class. Patients currently undergoing surgery are in general older, with more severe angina, more comorbidity and more extensive coronary disease as compared with the population randomized in the earlier studies. Angioplasty has been shown to improve symptoms and to reduce the need for surgery in certain patients. Recent changes in procedural techniques and adjunctive therapies have reduced the number of acute complications and the rate of restenosis. However, recent evidence suggests that some patients with mild angina (< class 2) or good exercise tolerance may not benefit as much from angioplasty as other patients with more severe angina.

Inadequate control of lipid levels in patients with a previous myocardial infarction.

AIM: To access the current lipid management of late survivors of acute myocardial infarction. METHODS: A systematic follow-up of all survivors who had previously been screened for enrolment into one of three randomised clinical trials in Auckland was undertaken from December 1995 to January 1997. All contacted survivors were asked to answer a questionnaire regarding their current therapy and were invited to undergo venepuncture for a lipid assay. RESULTS: Of the 1036 patients with acute myocardial infarction screened for enrolment in the three trials there were 984 (95%) who survived 30 days. At a median of 5.5 years (interquartile range 3.2-8.5) follow-up, 641 (86%) survivors agreed to have a fasting lipid test. The mean total cholesterol level was 5.7 +/- 1.1 mmol/L high density lipoprotein cholesterol 1.1 +/- 0.3 mmol/L, low density lipoprotein cholesterol 3.8 +/- 0.9 mmol/L and triglyceride level 1.9 +/- 1.1 mmol/L. Two hundred and seven (32%) patients were treated with a lipid-modifying agent. Four hundred and forty-five (69%) patients had a cholesterol level > or = 5.2 mmol/L 381 (59%) patients had a level > or = 5.5 mmol/L and 72 (11%) patients had a level > or = 7.0 mmol/L of whom 62 patients were not being treated with a lipid-modifying agent. For the 107 patients with coronary artery bypass grafts, the mean cholesterol level was 5.4 mmol/L and the mean low density lipoprotein cholesterol level was 3.7 +/- 0.9 mmol/L, with 57 (53%) patients not being treated with a "statin" or "fibrate". CONCLUSION: Lipid management is suboptimal in this high risk population of patients post-infarction and greater efforts need to be made to achieve better control. Diet is frequently inadequate in these patients at high risk and statin therapy is indicated.

Rosiglitazone and carotid IMT progression rate in a mixed cohort of patients with type 2 diabetes and the insulin resistance syndrome: main results from the Rosiglitazone Atherosclerosis Study.

OBJECTIVE: Insulin resistance is associated with progression of atherosclerosis. We assessed the effect of 12 months of treatment with rosiglitazone (RSG) on the progression of carotid intima-media thickness (IMT) in people with type 2 diabetes mellitus (T2DM) or the insulin resistance syndrome (IRS). DESIGN: Randomized, double-blind, placebo-controlled trial. SETTING: Malmö University Hospital, Malmö, Sweden. SUBJECTS: 555 subjects (200 with T2DM and 355 nondiabetics with IRS according to EGIR criteria), aged 35-80 years. 447 subjects (165 T2DM and 282 IRS) completed the study. INTERVENTION: Participants were allocated to placebo or RSG 4 mg for 2 months and then 8 mg daily. MAIN OUTCOME MEASURE: Change in composite IMT [mean IMT in the common carotid artery (CCA) and maximal IMT in the bulb] was the primary and various other IMT measures were secondary outcome variables. RESULTS: There was no effect of RSG treatment in the mixed population. In T2DM patients there was a reduced progression of the composite IMT (mean change: 0.041 vs. 0.070 mm, P = 0.07), and of the mean IMT CCA (mean change: -0.005 mm vs. 0.021 mm, P = 0.007). RSG treatment led to significant reductions of HOMA-IR, fasting plasma glucose, HbA1c, PAI-1 activity, fibrinogen, C-reactive protein and matrix metalloproteinase-9. CONCLUSIONS: In a mixed study population of patients with T2DM and IRS RSG treatment was not associated with a statistically significant reduction of carotid IMT progression rate. Separate analyses of these two patient groups indicated, however, a significant beneficial effect on CCA IMT in T2DM patients but no similar effect in subjects with IRS.

Wave-energy patterns in carotid, brachial, and radial arteries: a noninvasive approach using wave-intensity analysis.

The study of wave propagation at different points in the arterial circulation may provide useful information regarding ventriculoarterial interactions. We describe a number of hemodynamic parameters in the carotid, brachial, and radial arteries of normal subjects by using noninvasive techniques and wave-intensity analysis (WIA). Twenty-one normal adult subjects (14 men and 7 women, mean age 44 +/- 6 yr) underwent applanation tonometry and pulsed-wave Doppler studies of the right common carotid, brachial, and radial arteries. After ensemble averaging of the pressure and flow-velocity data, local hydraulic work was determined and a pressure-flow velocity loop was used to determine local wave speed. WIA was then applied to determine the magnitude, timings, and energies of individual waves. At all sites, forward-traveling (S) and backward-traveling (R) compression waves were observed in early systole. In mid- and late systole, forward-traveling expansion waves (X and D) were also seen. Wave speed was significantly higher in the brachial (6.97 +/- 0.58 m/s) and radial (6.78 +/- 0.62 m/s) arteries compared with the carotid artery (5.40 +/- 0.34 m/s; P < 0.05). S-wave energy was greatest in the brachial artery (993.5 +/- 87.8 mJ/m2), but R-wave energy was greatest in the radial artery (176.9 +/- 19.9 mJ/m2). X-wave energy was significantly higher in the brachial and radial arteries (176.4 +/- 32.7 and 163.2 +/- 30.5 mJ/m2, respectively) compared with the carotid artery (41.0 +/- 9.4 mJ/m2; P < 0.001). WIA illustrates important differences in wave patterns between peripheral arteries and may provide a method for understanding ventriculo-arterial interactions in the time domain.

Needle phobia in type 1 diabetes mellitus.

Needle phobia in patients with Type 1 (insulin-dependent) diabetes mellitus is difficult to manage. We report a case of long-standing needle phobia in a patient with 33 years of Type 1 diabetes mellitus who has developed very few vascular complications. Further studies are required to identify the prevalence of needle phobia in Type 1 diabetes mellitus. Once these individuals have been identified, appropriate psychological and physical treatments should be implemented, in the hope of making such individuals less fearful of the treatment of their condition.

Ongoing clinical trials of anti-platelet agents in the management of acute ischaemic coronary syndromes.

Acute ischaemic coronary syndromes, the clinical sequelae of thrombosis over a fissured atherosclerotic plaque within the coronary circulation, are the leading cause of death and hospitalisation in Western countries. Platelets are fundamental for the initiation and continuation of thrombosis, and currently available anti-platelet agents such as aspirin significantly improve the clinical outcome of patients with these syndromes. Therapeutic success with available therapy is however not universal, and adverse clinical event rates remain high. Several new classes of agents with a variety of anti-platelet actions are currently under development. Those which inhibit the final common pathway of platelet aggregation, the glycoprotein (GP) IIb/IIIa receptor, appear to show the most promise. Much clinical trial evidence already exists supporting the use of GP IIb/IIIa receptor antagonists in the management of acute ischaemic coronary syndromes. Several clinical studies are underway to further refine this knowledge base, and to assess their efficacy in a variety of novel applications.