Reactive hyperemia vs treadmill exercise testing in arterial disease

We compared the ankle pressure response during reactive hyperemia to the response to treadmill exercise in 28 limbs of 14 normal individuals and 26 legs of 15 patients with arterial occlusive disease. The mean percent maximum drop in ankle blood pressure during reactive hyperemia in normal limbs, 17% +/- 11% (+/- 1 SD) was significantly less than that of legs with arterial disease, 54% +/- 15% (P less than .001). Abnormal values were recorded in all but three diseased limbs. There was good correlation between the ankle pressure responses to reactive hyperemia and treadmill exercise (r = 0.71, P less than .001). This study suggests that measurement of ankle pressure during reactive hyperemia may be a useful substitute for treadmill testing to determine the functional capacity of the circulation during stress in patients with arterial occlusive disease. Reactive hyperemia testing requires less time and equipment and may be performed in patients who might be at risk or unable to carry out treadmill exercise.     

Short-term effects of cycle and treadmill training on exercise tolerance in peripheral arterial disease

BACKGROUND: To explore the efficacy of cycle training in the treatment of intermittent claudication, the present study compared performance and physiologic effects of cycle training with more conventional treadmill walking training in a group of patients with claudication. METHOD: Forty-two individuals with peripheral arterial disease and intermittent claudication (24 men, 18 women) were stratified by gender and the presence or absence of type 2 diabetes mellitus and then randomized to a treadmill (n = 13), cycle (n = 15), or control group (n = 14). Treadmill and cycle groups trained three times a week for 6 weeks, whereas the control group did not train during this period. Maximal and pain-free exercise times were measured on graded treadmill and cycle tests before and after training. RESULTS: Treadmill training significantly improved maximal and pain-free treadmill walking times but did not improve cycle performance. Cycle training significantly improved maximal cycle time but did not improve treadmill performance. However, there was evidence of a stronger cross-transfer effect between the training modes for patients who reported a common limiting symptom during cycling and walking at baseline. There was also considerable variation in the training response to cycling, and a subgroup of responsive patients in the cycle group improved their walking performance by more than the average response observed in the treadmill group. CONCLUSION: These findings suggest that cycle exercise is not effective in improving walking performance in all claudication patients but might be an effective alternative to walking in those who exhibit similar limiting symptoms during both types of exercise.     

Near patient cholesterol testing in patients with peripheral arterial disease.

AIMS: To assess the bias, precision and utility of the Bioscanner 2000 for near patient testing of total cholesterol (NPTC) in patients with peripheral arterial disease (PAD). METHODS: One hundred consecutive patients attending a hospital-based clinic with symptomatic PAD underwent non-fasting NPTC using finger prick blood sample and a laboratory total cholesterol (TC) using blood drawn from an antecubital fossa vein. RESULTS: The Bioscanner 2000 showed good precision with a coefficient of variation of 1.8-3.8%. NPTC was significantly lower than laboratory TC (mean (S.D.) 4.67 (1.1) vs. 5.12 (1.2) mmol/l), p < or = 0.01, paired Student's t-test. Comparing the two methods using Deming regression revealed a 15% negative bias for the Bioscanner 2000 compared to laboratory testing, which was demonstrated to be a systematic bias using a Bland-Altman plot. Almost half (46%) of the readings differed by > 0.5 mmol/l, 16% by > 1.0 mmol/l and 3% by > 2 mmol/l. This means that if the cut-off for statin treatment were taken as a TC of 5.0 or 3.5 mmol/l then, based on NPTC, alone 18 and 6% of patients, respectively, would not have received a statin. CONCLUSIONS: In the present study, NPTC significantly under-estimated TC when compared to laboratory testing. However, in the majority of cases, this would not have affected the decision to prescribe a statin and NPTC testing allows the immediate institution or titration of statin treatment.     

The value of cardiac monitoring during peripheral arterial stress testing in the surgical management of peripheral vascular disease

Eighty-six patients presenting with lower extremity pain on exertion underwent treadmill peripheral arterial stress testing with simultaneous cardiac monitoring. Of these patients 19 went on to have vascular reconstruction. Cardiac monitoring of peripheral arterial stress testing is a sensitive method of revealing occult cardiac disease in these high risk patients. It provides valuable information that can contribute to the surgical management of these patients. Specifically, ischemic exercise EKG patterns developed in 69.2% of patients with non-ischemic resting EKG patterns. Further, 80% of patients denying cardiopulmonary symptoms during peripheral arterial stress testing developed ischemic exercise EKG patterns. Of nine patients with significant ischemia on treadmill testing, two had vascular reconstruction postponed until after coronary artery bypass, four had extra-anatomic bypass. Two cardiac-related complications occurred, both in patients with ischemic exercise EKG patterns undergoing femoral-popliteal bypass.     

Mitochondriopathy of peripheral arterial disease

The signs and symptoms of peripheral arterial occlusive disease (PAD), including claudication, rest pain, and tissue loss, are consequences of compromised bioenergetics and oxidative tissue injury within the affected lower extremities. Compromised bioenergetics is the result of a combination of low blood flow through diseased arteries and diminished adenosine triphosphate production by dysfunctional mitochondria. The tissue injury appears to be secondary to increased production of reactive oxygen species by dysfunctional mitochondria and by inflammation, in association with ischemia and ischemia/reperfusion. In this review, we present the current histomorphologic, physiologic, and biochemical evidence defining the nature of this mitochondriopathy and discuss its contribution to the pathogenesis and clinical manifestations of PAD.     

Laser angioplasty in peripheral arterial disease

Laser angioplasty was performed in 66 patients with total occlusion of the ilio-femoral artery. The system used consisted of a pulsed dye laser operating at 480 nm, 50 mJ pulse^–1, 2s pulse^–1 and 5 Hz. The treatment laser was coupled into a 200m optical fibre wrapped around a coil for improved flexibility and radiopacity. The treatment laser was connected with a diagnostic laser consisting of a continuous wave helium-cadmium laser operating at 325 nm, 50 ms and 3 mW for tissue detection using fluorescence spectroscopy. The primary success rate was 82%, the complication rate was 15% without any clinical sequelae and the 18 month follow-up patency rate was 64%. Due to the narrow pilot channel created by laser angioplasty, in each case a complementary balloon angioplasty was required to restore the arterial lumen. The success rate did not depend upon the length of occlusion but was rather related to the extent of calcification. Laser angioplasty guided by spectroscopy is effective and safe in patients with totally occluded peripheral arteries in whom mechanical devices failed to cross the obstruction.     

Inflammatory profiling of peripheral arterial disease

The progression of peripheral arterial disease (PAD) is poorly understood but may be caused by an underlying inflammatory dysfunction. This study therefore profiled interleukin (IL)-1beta, IL-2, IL-4, IL-6, IL-8, IL-10, IL-13, anticardiolipin, and anti-beta2-glycoprotein 1 antibody concentrations and characterized patients' inflammatory response in vitro. Patients were classified according to World Health Organization criteria and ankle-brachial pressure index into critical ischemics (n=20), stable claudicants (n=20), and controls (n=20). In vitro studies involved culturing whole blood with RPMI-1640 for 24hr with and without 1 microg/mL lipopolysaccharide and profiling cytokine production. Autoantibody levels were measured using enzyme-linked immunosorbent assays, while cytokine profiles were determined by multiplex immunoassay. Serum IL-6, IL-10, IL-13, and anti-beta2-glycoprotein 1 antibody levels were higher in PAD (p<0.05). In the case of IL-6 and anti-beta2-glycoprotein 1 antibody, levels reflected increasing disease severity (p<0.05). In vitro studies revealed that IL-8 and IL-13 secretory capacities were significantly higher in PAD after 6 hr. However, when these were standardized against patient leukocyte count, cytokine production profiles did not differ. PAD features an increased inflammatory burden irrespective of Th1:Th2 cytokine type; this is more pronounced with increasing disease severity. However, the inflammatory hyperresponsiveness of cultured whole blood from PAD patients probably relates to associated leukocytosis, rather than being attributable to an inherent inflammatory dysfunction.     

Hyperlipidemia in peripheral atherosclerotic arterial disease.

One hundred and ten patients with radiologically established peripheral atherosclerotic arterial disease were studied. None of them suffered from diabetes, endocrine disorders or renal disease. Their serum cholesterol and triglyceride values were compared with those of a reference group consisting of 548 individuals. When the 95th percentile of the reference values was used for cut-off, the frequency of hyperlipidemias in the patients with peripheral arterial atherosclerosis was about 52%. Combined hyperlipidemia was slightly more common (21%) than isolated increase of either cholesterol (17.9%) or triglycerides (12.6%). Using other cut-off limits for the definition of hyperlipidemia, a striking change in the distribution between these three types of hyperlipidemia occurred. In our patients, the frequencies of different blood groups were not significantly different from those of a comparable population. The serum lipids were at the same level in the different blood groups.     

Antiplatelet therapy in peripheral occlusive arterial disease

BACKGROUND: Antiplatelet therapy (APT) in patients with peripheral occlusive arterial disease (POAD) may reduce cardiovascular (CV) morbidity and mortality by inhibiting atherothrombosis. This article reviews the current evidence for APT in patients with stable POAD and in patients undergoing revascularization procedures for POAD. METHODS: A Medline and Pubmed literature search (January 1966 to February 2003) was conducted to identify articles relating APT and POAD. Manual cross referencing was also used. RESULTS AND CONCLUSIONS: Meta-analyses suggest that APT (most commonly aspirin) in patients with stable POAD significantly reduces the incidence of nonfatal stroke, myocardial infarction and CV death. However, this conclusion is based on subset analysis of data predominantly involving patients with coronary and cerebrovascular atherosclerosis. There is a little direct evidence for the use of aspirin in patients with isolated POAD, but in practice, aspirin remains the most commonly used antiplatelet agent as high rates of coronary and cerebrovascular diseases are observed in this patient population. For patients with POAD without additional indicators of vascular risk, the protective effect of aspirin is unclear and dependent on the balance of risks and benefits in the individual patient. For patients undergoing peripheral revascularization, ticlopidine and aspirin in combination with dipyridamole are effective in maintaining patency after bypass procedures and following angioplasty/femoral endarterectomy. The efficacy of thienopyridines in peripheral angioplasty is uncertain, and the optimum timing and duration of APT relative to intervention are not known.     

Changing practice patterns in peripheral arterial disease

The development of interventional radiologic techniques during the past decade has changed our approach to the treatment of lower extremity peripheral arterial disease (LE-PAD). Balloon and laser-assisted angioplasty, atherectomy (rotary and directional devices), stent implantation, and thrombolysis as well as combinations of all of these approaches, at times with concomitant or secondary surgery, have been used in our institution. A review of our practice patterns during the past 5 years was performed to analyze changing attitudes and results with these newer techniques. All new patients seen in consultation for LE-PAD during three alternate years were reviewed with regard to demographics, initial complaints, initial treatment modality, initial outcome, indications for and results of secondary treatment, and ultimate outcome (at 1 year). The 603 patients were seen during the following three 12-month periods: 1987 to 1988, 1989 to 1990, and 1991 to 1992. An intention-to-treat analysis revealed (1) the number of patients seen for peripheral arterial disease has increased steadily; (2) in the last year more were initially treated with intervention as the primary modality; (3) the results of such catheter-based procedures improved only slightly over this 5-year period, despite our learning curve and the fact that we discarded several ineffective interventional approaches; (4) the fraction of patients primarily operated on and the excellent results of surgery have not changed; and (5) the number of operations for proximal (aortoiliac) disease has decreased markedly, with a corresponding increase in distal reconstructions. The evolution of our current approach to the treatment of LE-PAD is based on this continuing experience.Presented at the Eighth Annual Meeting of the Western Vascular Society, Sonoma, Calif, January 10–12, 1992.     

Life-style modification in peripheral arterial disease.

OBJECTIVE: To review the published evidence supporting the use of life-style modification in peripheral arterial disease (PAD). DESIGN: A systematic search of the medical literature was performed for relevant studies. MATERIALS: The publications obtained were then searched for randomised clinical trials which reported end-points of mortality or major cardiovascular event rates with various life-style modifications. RESULTS: Only one randomised controlled trial was found reporting relevant end-points. Other trials were of other end-points such as walking distance or biochemical markers. CONCLUSIONS: There is a lack of randomised controlled data proving the benefit of life-style modification in improving mortality and reducing cardiovascular events in patients with PAD. Despite this there is sufficient evidence to recommend some life-style modification as part of the overall approach to risk reduction in these patients. There is compelling evidence to support smoking cessation, increased exercise and improved diet.     

Spinal cord stimulation in peripheral arterial disease. A cooperative study

Percutaneous epidural stimulation of the low thoracic spinal cord was carried out in 41 patients with pain from peripheral arterial disease of the lower limbs. Results are reported relating to pain, claudication distance, peripheral blood flow, and trophic lesion changes. Following a trial period of stimulation, 37 patients had stimulators permanently implanted. After a mean poststimulation follow-up period of 25 months, substantial pain relief (75% to 100%) was obtained in 29 cases; claudication distance significantly increased in 15 cases; Doppler ultrasound recordings of lower-limb distal arteries showed a tendency toward normalization of pulse-wave morphology, with increase of amplitude in 12 of the 23 patients studied; a rise in skin temperature was also detected by thermography. Distal arterial blood pressure remained unchanged with stimulation. Ischemic cutaneous trophic lesions of less than 3 sq cm healed, but gangrenous conditions were not benefited. A placebo effect or the natural history of the disease can be excluded as the reason for these improvements. It is concluded that spinal cord stimulation is a valid alternative treatment for moderate peripheral arterial disorders when direct arterial surgery is not possible or has been unsuccessful.     

Cost-identification analysis of revascularization procedures on patients with peripheral arterial occlusive disease

Objective: To determine average total in-hospital costs of various revascularization procedures for peripheral arterial occlusive disease; to examine the effect of procedure-related complications and patient characteristics on these costs; and to examine whether costs have changed over time. Methods: We collected cost data on all admissions involving one revascularization procedure for peripheral arterial occlusive disease at the Brigham and Women's hospital from 1990 through 1995 (n = 583). The main outcome measures were total costs per admission in 1995 US dollars and length of stay in days. Results: For each of 12 different procedures identified, total costs per admission varied considerably. Multiple linear regression analysis was performed to determine the effect of local and systemic complications and of patient characteristics on total in-hospital costs per admission. The additional cost incurred for fatal systemic complications was $11,675 (P = .004) and for nonfatal systemic complications was $9345 (P < .001). The results demonstrated significant additional costs with management of critical ischemia versus intermittent claudication ($4478, P < .001), presence of coronary artery disease ($1287, P = .05), female sex ($1461, P = .03), and advanced age ($1345, P = .02). No statistically significant changes over time were demonstrated. Conclusion: Total in-hospital costs per admission for peripheral revascularization procedures are highly variable and significantly increased by procedure-related complications, advanced age, female sex, management of critical ischemia, and presence of coronary artery disease. (J Vasc Surg 1998;28:617-23.)