Lloyd M. Taylor

ACC/AHA 2005 practice guidelines for the management of patients with peripheral arterial disease (lower extremity, renal, mesenteric, and abdominal aortic) : A collaborative report from the American Association for Vascular Surgery/Society for Vascular Su

Patients With Peripheral Arterial Disease (Lower Extremity, Renal, Mesenteric, and Abdominal Aortic) A Collaborative Report from the American Association for Vascular Surgery/Society for Vascular Surgery,* Society for Cardiovascular Angiography and Interventions, Society for Vascular Medicine and Biology, Society of Interventional Radiology, and the ACC/AHA Task Force on Practice Guidelines (Writing Committee to Develop Guidelines for the Management of Patients With Peripheral Arterial Disease) Endorsed by the American Association of Cardiovascular and Pulmonary Rehabilitation; National Heart, Lung, and Blood Institute; Society for Vascular Nursing; TransAtlantic Inter-Society Consensus; and Vascular Disease Foundation

Diagnosis and Treatment of Chronic Arterial Insufficiency of the Lower Extremities: A Critical Review

Atherosclerosis is the most common cause of chronic arterial occlusive disease of the lower extremities. The arterial narrowing or obstruction that occurs as a result of the atherosclerotic process reduces blood flow to the lower limb during exercise or at rest. A spectrum of symptoms results, the severity of which depends on the extent of the involvement and the available collateral circulation. Thus, symptoms may range from intermittent claudication to pain at rest. Intermittent claudication denotes pain that develops in the affected limb with exercise and is relieved with rest. This pain usually occurs distal to the arterial narrowing or obstruction. Since the superficial femoral and popliteal arteries are the vessels most commonly affected by the atherosclerotic process, the pain of intermittent claudication is most often localized to the calf. The distal aorta and its bifurcation into the two iliac arteries are the next most frequent sites of involvement. Narrowing of these arteries may produce pain in the buttocks or the thighs as well as the legs. Epidemiological studies indicate that up to 5% of men and 2.5% of women 60 years of age or older have symptoms of intermittent claudication.1 2 The prevalence is at least threefold higher when sensitive noninvasive tests are used to make the diagnosis of arterial insufficiency in asymptomatic and symptomatic individuals.3 The symptoms of chronic arterial insufficiency of the lower extremities progress rather slowly over time. Thus, after 5 to 10 years, more than 70% of patients report either no change or improvement in their symptoms, while 20% to 30% have progressive symptoms and require intervention, and less than 10% need amputation.4 5 Despite the relatively benign prognosis for the affected limb, however, symptoms of intermittent claudication should be viewed as a sign of systemic atherosclerosis. This explains why, compared with …

Present status of reversed vein bypass grafting: Five-year results of a modern series

From January 1980 through December 1988, 564 limbs in 434 patients were treated for infrainguinal arterial ischemia. Of these, 516 limbs in 387 patients underwent reversed vein bypass grafting. The remainder were treated by primary amputation (11 limbs, 1.9%) or by prosthetic bypass (37 limbs, 6.4%). The indications for operation were limb salvage in 80% of limbs and claudication in 20%. Adequate ipsilateral greater saphenous vein was available for 285 (55%) grafts, with reversed vein bypass achieved in the other 231 operations by use of distal graft origins (151 grafts), use of alternate vein sources (120 grafts), and splicing of venous segments (81 grafts). Seventy-six grafts (15%) were to the above-knee popliteal artery, 199 grafts (37%) were to the below-knee popliteal artery, and 241 grafts (47%) were to infrapopliteal arteries, 26 of which (11%) were to inframalleolar arteries. The primary and secondary patencies for all grafts at 5 years were 75% and 81%, respectively. Grafts to infrapopliteal arteries had significantly worse primary patency (69%) at 5 years than did grafts to the popliteal artery (77%, above knee; 80%, below knee) and grafts formed of adequate ipsilateral greater saphenous vein had significantly better primary patency (80%) than did grafts performed when this conduit was not available (68%). Secondary patency of all graft categories ranged from 76% to 85%, and there were no significant differences regardless of site of distal anastomosis, source of venous conduit, or site of graft origins. We prefer the use of reversed vein bypass grafting for lower extremity revascularization both because of the excellent patency results and because the technique can be applied to the larger number of patients in our practice who lack intact ipsilateral greater saphenous vein, in contrast to in situ vein bypass procedures.

ACC/AHA Guidelines for the Management of Patients with Peripheral Arterial Disease (Lower Extremity, Renal, Mesenteric, and Abdominal Aortic)

A Collaborative Report from the American Associations for Vascular Surgery/Society for Vascular Surgery,* Society for Cardiovascular Angiography and Interventions, Society for Vascular Medicine and Biology, Society of Interventional Radiology, and the ACC/AHA Task Force on Practice Guidelines (Writing Committee to Develop Guidelines for the Management of Patients with Peripheral Arterial Disease)—Summary of Recommendations

The association of elevated plasma homocyst(e)ine with progression of symptomatic peripheral arterial disease

Plasma homocyst(e)ine (the sum of free and bound homocysteine, homocystine, and the mixed disulfide homocysteine-cysteine, expressed as homocysteine) levels were determined by high performance liquid chromatography in 214 patients with symptomatic (claudication, rest pain, gangrene, amputation) lower extremity arterial occlusive disease and/or symptomatic (stroke, cerebral transient ischemic attacks) cerebral vascular disease and in 103 control persons. Mean plasma homocyst(e)ine was significantly higher in patients than in controls (14.37 +/- 6.89 nmol/ml vs 10.10 +/- 2.16, p less than 0.05). Thirty-nine percent of patients (83 of 214) had plasma homocyst(e)ine values greater than control mean + 2 standard deviations. Plasma homocyst(e)ine values were contrasted to age, male sex, diabetes, hypertension, smoking, renal failure, and plasma cholesterol. No difference was found in the incidence and/or level of any of these risk factors when patients with normal plasma homocyst(e)ine were compared to those with elevated plasma homocyst(e)ine, both by univariate and multivariate analysis. Patients with elevated plasma homocyst(e)ine were more likely to demonstrate clinical progression of lower extremity disease and of coronary artery disease, but not of cerebral vascular disease than were patients with normal plasma homocyst(e)ine, and the rate of progression was more rapid (p = 0.002). Progression of lower extremity disease as assessed in the vascular laboratory was also more common in patients with elevated plasma homocyst(e)ine (p = 0.01). We conclude that elevated plasma homocyst(e)ine is an independent risk factor for symptomatic lower extremity disease or cerebral vascular disease or both. Symptomatic patients with lower extremity disease and with elevated plasma homocyst(e)ine also appear to have more rapid progression of disease.

Common Mutation in Methylenetetrahydrofolate Reductase Correlation With Homocysteine Metabolism and Late-Onset Vascular Disease

BACKGROUND Increased homocysteine levels are a risk factor for atherosclerosis and its sequelae. A common genetic mutation in methylenetetrahydrofolate reductase (MTHFR), an enzyme required for efficient homocysteine metabolism, creates a thermolabile enzyme with reduced activity. We determined the prevalence of this mutation in many subjects with and without vascular disease and related it to homocysteine and folate levels. METHODS AND RESULTS DNA from 247 older subjects with vascular disease and 594 healthy subjects without vascular disease (in three different control groups) was screened for the MTHFR 677 C-to-T mutation. Within each group, 9% to 17% of the subjects were homozygous for this mutation, and the mutant allele frequency was 31% to 39%. The genotype distributions, homozygote frequencies, and allele frequencies did not differ significantly between the study groups. In the vascular disease subjects, despite significantly lower folate levels in MTHFR homozygotes, there was no significant difference in homocysteine levels among the MTHFR genotype groups. The negative slope of the regression line relating homocysteine and folate was significantly steeper for those with a homozygous MTHFR mutation compared with those without this mutation. CONCLUSIONS Although the thermolabile MTHFR mutation is very common, it does not appear to be a significant genetic risk factor for typical late-onset vascular disease. Because MTHFR homozygotes have increased homocysteine with low folate levels, this mutation may contribute to early-onset or familial vascular disease. The genotype dependence of the folate-homocysteine correlation further suggests that homozygotes for this mutation may have both an exaggerated hyperhomocysteinemic response to folic acid depletion and a better response to folic acid therapy.

Screening for asymptomatic internal carotid artery stenosis: Duplex criteria for discriminating 60% to 99% stenosis

PURPOSE The Asymptomatic Carotid Atherosclerosis Study (ACAS) showed that carotid endarterectomy reduces stroke risk in symptom-free patients with 60% or greater internal carotid artery (ICA) stenosis. This will surely lead to the performance of an increased number of screening duplex examinations. Assuming that positive study results will lead to arteriography or endarterectomy and keeping in mind the modest benefit for prophylactic endarterectomy demonstrated by ACAS (absolute risk reduction for ipsilateral stroke of 5.8% at 5 years), duplex criteria for 60% or greater ICA stenosis must have high positive predictive values (PPV). Determining criteria for 60% or greater stenosis, which emphasized high accuracy and PPV, forms the basis for this study. METHODS Stenoses detected by angiography in 352 ICAs were blindly compared with those detected by duplex scanning. Duplex criteria were determined for highest overall accuracy in detection of 60% or greater ICA stenosis and for 95% or greater PPV. RESULTS Maximal accuracy for detection of 60% or greater stenosis was 90%. This was achieved by the combination of a peak systolic velocity of 260 cm/sec or greater and an end diastolic velocity of 70 cm/sec or greater (sensitivity 84%, specificity 94%, PPV 92%). The 95% PPV for 60% or greater stenosis results from combining peak systolic velocity of 290 cm/sec or greater and end diastolic velocity of 80 cm/sec or greater. CONCLUSIONS With use of these criteria duplex scanning accurately detects with high PPVs the threshold level of ICA stenosis defined in ACAS as receiving stroke reduction benefit from prophylactic carotid endarterectomy. These criteria should be useful for carotid artery screening and minimizing unneeded intervention.

Statin Use and Leg Functioning in Patients With and Without Lower-Extremity Peripheral Arterial Disease

Background—We determined whether statin use (versus nonuse) is associated with superior lower-extremity functioning independently of cholesterol levels and other confounders in patients with and without peripheral arterial disease. Methods and Results—Participants included 392 men and women with an ankle brachial index (ABI) <0.90 and 249 with ABI 0.90 to 1.50. Functional outcomes included 6-minute walk distance and 4-meter walking velocity. A summary performance score combined performance in walking speed, standing balance, and time for 5 repeated chair rises into an ordinal score ranging from 0 to 12 (12=best). Adjusting for age, sex, ABI, comorbidities, education level, medical insurance status, cholesterol, and other confounders, participants taking statins had better 6-minute walk performance (1276 versus 1218 feet, P =0.045), faster walking velocity (0.93 versus 0.89 m/s, P =0.006), and a higher summary performance score (10.2 versus 9.4, P <0.001) than participants not taking statins. Positive associations were attenuated slightly after additional adjustment for C-reactive protein level but remained statistically significant for walking velocity and the summary performance score. We did not find significant associations between lower-extremity functioning and aspirin, ACE inhibitors, vasodilators, or &bgr;-blockers. Conclusions—Statin use is associated with superior leg functioning compared with no statin use, independent of cholesterol levels and other potential confounders. These data suggest that non–cholesterol-lowering properties of statins may favorably influence functioning in persons with and without peripheral arterial disease.

Mesenteric duplex scanning: A blinded prospective study☆☆☆

PURPOSE Based on retrospective comparisons of duplex scanning with arteriography of the celiac (CA) and superior mesenteric (SMA) arteries in 34 patients, we previously suggested that an SMA peak systolic velocity of 275 cm/sec or greater or no flow signal and a CA PSV of 200 cm/sec or greater or no flow signal were reliable indicators of a 70% or greater angiographic stenosis of the SMA and CA, respectively. We now report the results of a blinded, prospective study in a larger patient group designed to determine the ability of mesenteric duplex scanning to visualize the CA and SMA and to validate our proposed duplex criteria for splanchnic artery stenosis. METHODS During an 18-month period 100 patients admitted to our vascular surgery service for aortography underwent routine mesenteric artery duplex scanning and lateral abdominal aortography regardless of abdominal symptoms. The lateral aortograms were evaluated to determine the presence or absence of a 70% or greater stenosis in the CA or SMA. Duplex-determined peak systolic velocities from the CA and SMA were recorded without knowledge of the angiographic results. RESULTS Aortography satisfactorily visualized 100% of the CAs and 99% of the SMAs. Of these, 93% of the SMAs and 83% of the CAs were visualized by duplex. According to the above criteria, duplex sensitivity, specificity, positive predictive value, negative predictive value, and overall accuracy for detection of a 70% or greater SMA stenosis were 92%, 96%, 80%, 99%, and 96% and for a 70% or greater CA stenosis 87%, 80%, 63%, 94%, and 82%. CONCLUSIONS Mesenteric duplex scanning is feasible in the majority of patients. Prospective evaluation of duplex diagnostic criteria for 70% or greater stenosis indicates that mesenteric duplex scanning is sufficiently accurate to be clinically useful as a screening examination to detect SMA and CA stenosis.

Prospective blinded study of the relationship between plasma homocysteine and progression of symptomatic peripheral arterial disease

PURPOSE An elevated plasma homocysteine level is an established risk factor for atherosclerotic coronary heart disease (CHD), cerebrovascular disease (CVD), and lower extremity occlusive disease (LED). An elevated plasma homocysteine level can be reduced by therapy with folate and vitamins B6 and B12. An accurate evaluation of the role of vitamin therapy requires knowledge of the influence of plasma homocysteine levels on the progression of CHD, CVD, and LED. METHODS The Homocysteine and Progression of Atherosclerosis Study is a blinded prospective study of the influence of homocysteine and of other atherosclerotic risk factors on the progression of disease in patients with symptomatic CVD, LED, or both. This study is set in a university hospital vascular surgery clinic and the General Clinical Research Center. Consecutive patients with stable symptomatic CVD or LED underwent baseline clinical, laboratory, and vascular laboratory testing for homocysteine and other risk factors and were examined every 6 months. The primary endpoints were ankle brachial pressure index, duplex scan-determined carotid stenosis, and death. The secondary endpoints were the clinical progressions of CHD, LED, and CVD. The hypothesis that was tested was whether the progression of symptomatic CVD or LED was more frequent or more rapid in patients with elevated plasma homocysteine levels. plasma homocysteine levels. RESULTS After a mean follow-up period of 37 months (range, 1 to 78 months) for deaths from all causes (>14 micromol/L; elevated, 18.6%; normal, 9.4%; P = .022), deaths from cardiovascular disease (elevated, 12.5%; normal, 6.3%; P = .05) and the clinical progression of CHD (highest 20% of homocysteine levels, 80%; lowest 20% of homocysteine levels, 39%; P = .007) were significantly more frequent or more rapid by life-table analysis when the homocysteine levels were elevated. Multivariate Cox proportional hazards regression model showed a significant independent and increasing relationship between the plasma homocysteine levels and the time to death (relative risk for highest one third of homocysteine values, 1.6; 95% confidence interval [CI], 1.04 to 2.56; P = 029; and relative risk for highest one fifth of homocysteine values, 3.13; 95% CI, 1.69 to 6.64; P = .0001). After an adjustment for age, smoking, hypertension, diabetes, cholesterol, and the vascular laboratory progression of CVD or LED, each 1.0 micromol/L increase in the plasma homocysteine levels resulted in a 3.6% increase (95% CI, 0.0% to 6.6%; P = .06) in the risk of death (all causes) at 3 years and a 5.6% increase (95% CI, 2.2% to 8.5%; P = .003) in the risk of death from cardiovascular disease. CONCLUSION We conclude that elevated plasma homocysteine levels are associated significantly with death, with death from cardiovascular disease, and with the progression of CHD in patients with symptomatic CVD or LED. These results strongly mandate clinical trials of homocysteine-lowering vitamin therapy in such patients.