Established and evolving medical therapies for claudication in patients with peripheral arterial disease

[Follow-up of patients with chronic obstructive arterial disease, some months after their rehabilitation: Assessment of a therapeutic education program]

Vascular rehabilitation (VR) is becoming increasingly important in the management of the arterial patient. Therapeutic Patient Education (TPE) is an integral part of rehabilitation programs and aims to transform patients' lifestyle habits. The effectiveness of patient management at short-term no longer needs to be demonstrated, but we can question the effectiveness of education over the long term, some months following a rehabilitation program.

OBJECTIVE

This study aims to assess, in the long term, the effects of TPE in VR, and to observe the transformation of certain lifestyle habits of patients.

METHOD

We convened 68 patients (51 men and 17 women) 6 months and 1 year after VR treatment during which these patients participated in an TPE program. We assessed: knowledge by questionnaire, walking range, weight and body composition by impedimetric techniques.

RESULTS

We found that patients improved their knowledge at the end of rehabilitation 45.8 (±7.6) of good responses on average, compared to 36.2 (±8.6) at the beginning of rehabilitation and these results are consolidated 6 months after 43.4 (±7.5) and 1 year after 44.1 (±8.1). We also found that walking distances during treadmill testing and outdoor walking improved at the end of rehabilitation and were maintained at six months and one year. Finally, weight, fat mass and lean mass decreased slightly compared to the end of rehabilitation. Only 7 patients out of 22 gave up smoking.

CONCLUSION

An education program concerning risk factor management during vascular rehabilitation enables patients to acquire knowledge that can be used to maintain new lifestyle habits and stabilize their health status.

Effect of Cilostazol Following Endovascular Intervention for Peripheral Artery Disease

Efficacy of endovascular therapy (EVT) with nitinol stents for femoropopliteal (FP) lesions is limited by restenosis. Oral cilostazol reduces angiographic restenosis rate; however, treatment duration remains unclear. In a retrospective analysis of a multicenter database of 3471 consecutive limbs in 2737 patients (mean age: 72 ± 9 years; 61% diabetic; and 26% on regular dialysis) undergoing EVT for FP lesions between January 2004 and December 2011, we compared Kaplan-Meier estimated primary patency after EVT followed or not by cilostazol treatment. We used Cox hazard regression analysis to assess temporal association between cilostazol treatment and post-EVT restenosis. Five-year primary patency was higher in the cilostazol group than in the noncilostazol group (57% vs 47%, P < .0001). Cilostazol treatment was inversely associated with restenosis for the first 2 years following EVT (P < .05); however, no significant association was observed thereafter. Cilostazol use therefore appears efficacious in preventing restenosis up to 2 years after EVT for FP lesions.

Cilostazol eliminates adverse smoking outcome in patients with drug-eluting stent implantation

BACKGROUND

The present study investigated whether cilostazol can eliminate adverse smoking outcome after percutaneous coronary intervention (PCI).

METHODS AND RESULTS

A total of 914 patients with successful drug-eluting stent (DES) implantation were randomly assigned to dual antiplatelet therapy (DAT; aspirin and clopidogrel, n=457) or to triple antiplatelet therapy (TAT; DAT with cilostazol, n=457). The effect of smoking on 2-year major adverse cardio/cerebrovascular events (MACCE) in both the TAT and DAT groups was evaluated. Total MACCE were not significantly different between the 2 anti-platelet regimens (9.8% in TAT vs. 11.4% in DAT groups, P=0.45), but the adverse effects of smoking on clinical outcome were different between DAT vs. TAT. Current smokers had a higher prevalence of MACCE than non-smokers in the DAT group (16.7% vs. 9.5%, P=0.04). In the TAT group, however, the adverse effect of smoking was abolished (9.2% vs. 10.1%, P=0.85). Regarding the effects of smoking on the antiplatelet effects of DAT or TAT, post-treatment platelet reactivity (in P2Y12 reaction units; PRU) in current smokers was not significantly lower than that in non-smokers in the DAT group, whereas, in the TAT group, it was significantly lower than that of non-smokers (189±88 vs. 216±89 PRU, P=0.01).

CONCLUSIONS

Adverse clinical effects of smoking may be eliminated by the addition of cilostazol to DAT after DES implantation. This may be due to the stimulation of cilostazol's antiplatelet effects by smoking.

Triple versus dual antiplatelet therapy after percutaneous coronary intervention for coronary bifurcation lesions: results from the COBIS (COronary BIfurcation Stent) II Registry

The efficacy and safety of adding cilostazol to aspirin plus clopidogrel (triple antiplatelet therapy, TAPT) have not been fully evaluated in complex percutaneous coronary intervention (PCI). We sought to investigate whether TAPT after PCI for bifurcation lesions improves long-term clinical outcomes. Consecutive patients undergoing PCI for bifurcation lesions were enrolled from 18 centers in Korea between 2003 and 2009. We compared target vessel failure (TVF), defined as a composite of cardiac death, myocardial infarction (MI), and target vessel revascularization (TVR), among 675 patients who received TAPT and 2081 who received dual antiplatelet therapy (DAPT: aspirin plus clopidogrel). Patients who received TAPT had more cardiovascular co-morbidities with regard to clinical, angiographic, and procedural characteristics. During the follow-up (median 36 months), 346 (12.6%) TVFs occurred. The incidence of TVF was significantly higher in the TAPT group, mainly driven by a higher TVR rate. In the TAPT group, however, the risk of TVF was not significantly different from the DAPT group after adjusting for the confounders of TVFs (adjusted hazard ratio [HR] 0.86, 95% confidence interval [CI] 0.53-1.39, p = 0.53). And also, there were no significant differences between the 2 groups in terms of the risks for death, cardiac death, MI, TVR, stent thrombosis, or cerebrovascular accident. These results were consistent after propensity score-matched analysis, and were also constant among the high-risk subgroups. TAPT after bifurcation PCI had no beneficial effect on the risk of long-term clinical outcomes in real-world clinical practice. Further studies are needed to confirm these findings.

Community walking programs for treatment of peripheral artery disease

BACKGROUND

Supervised walking programs offered at medical facilities for patients with peripheral artery disease (PAD) and intermittent claudication (IC), although effective, are often not used due to barriers, including lack of reimbursement and the need to travel to specialized locations for the training intervention. Walking programs for PAD patients that occur in community settings, such as those outside of supervised settings, may be a viable treatment option because they are convenient and potentially bypass the need for supervised walking. This review evaluated the various methods and outcomes of community walking programs for PAD.

METHODS

A literature review using appropriate search terms was conducted within PubMed/MEDLINE and the Cochrane databases to identify studies in the English language that used community walking programs to treat PAD patients with IC. Search results were reviewed, and relevant articles were identified that form the basis of this review. The primary outcome was peak walking performance on the treadmill.

RESULTS

Ten randomized controlled trials examining peak walking outcomes in 558 PAD patients demonstrated that supervised exercise programs were more effective than community walking studies that consisted of general recommendations for patients with IC to walk at home. Recent community trials that incorporated more advice and feedback for PAD patients in general resulted in similar outcomes, with no differences in peak walking time compared with supervised walking exercise groups.

CONCLUSIONS

Unstructured recommendations for patients with symptomatic PAD to exercise in the community are not efficacious. Community walking programs with more feedback and monitoring offer improvements in walking performance for patients with claudication and may bypass some obstacles associated with facility-based exercise programs.

Triple versus dual antiplatelet therapy for coronary heart disease patients undergoing percutaneous coronary intervention: A meta-analysis

Coronary heart disease (CHD) is the leading cause of mortality worldwide. Previous studies have suggested that cilostazol-based triple antiplatelet therapy (TAT) may be more effective than conventional dual antiplatelet therapy (DAT) at improving the clinical outcomes of patients with CHD undergoing percutaneous coronary intervention (PCI). However, individually published results are inconclusive. The present meta-analysis evaluated controlled clinical studies to compare the clinical outcomes between TAT and DAT in patients with CHD undergoing PCI. Ten controlled clinical studies were included, with a total of 7,670 patients with CHD undergoing PCI. The total number included 3,925 patients treated with DAT (aspirin and clopidogrel) and 3745 patients treated with TAT (addition of cilostazol to DAT). The crude odds ratio (OR) with a 95% confidence interval (CI) was calculated with either the fixed or random effects model. The meta-analysis results indicated that patients in the TAT group had a significantly lower rate of restenosis compared with that of the DAT group (OR=0.59, 95% CI: 0.45–0.77; P<0.001). The rate of major adverse cardiac events (MACE) and target lesion revascularization (TLR) in the TAT group were significantly lower compared with those in the DAT group (MACE: OR=0.69, 95% CI: 0.56–0.85, P<0.001; TLR: OR=0.61, 95% CI: 0.43–0.88, P=0.008). However, no significant differences between the TAT and DAT groups in terms of mortality rate, myocardial infarction, target vessel revascularization and stent thrombosis were observed. In conclusion, the results of the present meta-analysis indicated that the efficacy and safety of cilostazol-based TAT therapy is greater than that of conventional DAT therapy for patients with CHD undergoing PCI.

Comparison of On-Treatment Platelet Reactivity Between Triple Antiplatelet Therapy With Cilostazol and Standard Dual Antiplatelet Therapy in Patients Undergoing Coronary Interventions

Background:

The recent literature has shown that triple antiplatelet therapy with cilostazol in addition to the standard dual antiplatelet therapy with aspirin and clopidogrel may reduce platelet reactivity and improve clinical outcomes following percutaneous coronary intervention. The purpose of this meta-analysis is to compare the efficacy of triple antiplatelet therapy and dual antiplatelet therapy in regard to on-treatment platelet reactivity.

Methods:

Nine studies (n = 2179) comparing on-treatment platelet reactivity between dual antiplatelet therapy (n = 1193) and triple antiplatelet therapy (n = 986) in patients undergoing percutaneous coronary intervention were included. Primary end points were P2Y12 reaction unit (PRU) and platelet reactivity index (PRI). Secondary end points were platelet aggregation with adenosine diphosphate (ADP) 5 and 20 µmol/L and P2Y12% inhibition. Mean difference (MD) and 95% confidence intervals (CI) were computed and 2-sided α error <.05 was considered as a level of significance.

Results:

Compared to dual antiplatelet therapy, triple antiplatelet therapy had significantly lower maximum platelet aggregation with ADP 5 µmol/L (MD: −14.4, CI: −21.6 to −7.2, P < .001) and 20 µmol/L (MD: −14.9, CI: −22.9 to −6.8, P < .001), significantly lower PRUs (MD: −45, CI: −59.4 to −30.6, P < .001) and PRI (MD: −26, CI: −36.8 to −15.2, P < .001), and significantly higher P2Y12% inhibition (MD: 18.5, CI: 2.3 to 34.6, P = .025).

Conclusion:

Addition of cilostazol to conventional dual antiplatelet therapy significantly lowers platelet reactivity and may explain a decrease in thromboembolic events following coronary intervention; however, additional studies evaluating clinical outcomes will be helpful to determine the benefit of triple antiplatelet therapy.

Exercise therapy for claudication: latest advances

OPINION STATEMENT

Peripheral artery disease (PAD) creates a significant national and international healthcare burden. A first line treatment for PAD is supervised walking exercise in hospitals and clinics. Specifically, supervised walking exercise seeks to improve the classic symptom associated with PAD, intermittent claudication (IC), which is characterized by cramping, aching, and pain of the muscles in the lower extremities during walking. While effective, supervised walking exercise is often not prescribed or utilized due to a number of treatment barriers such as lack of transportation to clinical centers and lack of insurance reimbursement. Walking exercise in community settings is an option that has gained attention due to the limitations of supervised walking exercise, as community walking is generally more convenient in terms of a patient's schedule and may circumvent potential barriers such as treatment cost and transportation difficulties. However, more research is needed to improve the effectiveness of community-based walking programs since far less is known about the optimal structure of such programs. Other exercise therapy options are becoming available for PAD patients in addition to walking exercise. These modalities include but are not limited to leg and arm ergometry, polestriding and resistance training. These exercise therapy options have not to date been as well validated as supervised walking exercise. However, they may potentially be used in the event supervised walking exercise is not feasible or patient preference warrants an alternative exercise strategy.

Assessment of gait dynamics in rats submitted to limb ischemia

PURPOSE

To describe a method for the assessment of gait dynamics in rats submitted to limb ischemia.

METHODS

Twenty-four male Wistar rats (150-160g) were used. Twelve animals were submitted to limb ischemia by ligation of the common left iliac artery (ischemic group: n = 12); and a sham-operated group was used as control (n=12). After a recovery period of 6 weeks, gait dynamics was assessed by counting the complete footprints and the number of hindlimb-floor contacts during a treadmill test for five minutes at a speed of 12 m.min(-1) and angulation of 15°. The number of contacts of the left hindlimb was divided by the right hindlimb values (LRR) for group comparisons. Ischemic disability was quantified by comparing the area under curve (AUC) created by plotting each contact versus time for each hindlimb. The left hindlimb ischemic disability index (LHDI), which was compared between groups, was defined by the formula: LHDI = (1- AUC (left) / AUC (right)) x 100.

RESULTS

Surgery was well tolerated by all animals. Rats did not suffer tissue loss or ulcerations. Complete footprint LRR was 0.3 ± 0.08 for the ischemic group and 1.3 ± 0.9 for controls (p=0.0043). Number of contacts LLR was 0.5 ± 0.2 for the ischemic group and 1.0 ± 0.1 for the control group (p=0.0051). LHDI was 56.83 ± 10.67 for the ischemic group and 2.50 ± 13.10 for the control group (P = 0.031).

CONCLUSION

Assessment of gait dynamics in rats submitted to limb ischemia could be done by footprint analysis and hindlimb contact recording during a treadmill test.

Low-density lipoprotein lowering does not improve calf muscle perfusion, energetics, or exercise performance in peripheral arterial disease

OBJECTIVES

We hypothesized that low-density lipoprotein (LDL) reduction regardless of mechanism would improve calf muscle perfusion, energetics, or walking performance in peripheral arterial disease (PAD) as measured by magnetic resonance imaging and magnetic resonance spectroscopy.

BACKGROUND

Statins improve cardiovascular outcome in PAD, and some studies suggest improved walking performance.

METHODS

Sixty-eight patients with mild to moderate symptomatic PAD (age 65 ± 11 years; ankle-brachial index [ABI] 0.69 ± 0.14) were studied at baseline and annually for 2 years after beginning simvastatin 40 mg (n = 20) or simvastatin 40 mg/ezetimibe 10 mg (n = 18) if statin naïve, or ezetimibe 10 mg (n = 30) if taking a statin. Phosphocreatine recovery time was measured by (31)P magnetic resonance spectroscopy immediately after symptom-limited calf exercise on a 1.5-T scanner. Calf perfusion was measured using first-pass contrast-enhanced magnetic resonance imaging with 0.1 mM/kg gadolinium at peak exercise. Gadolinium-enhanced magnetic resonance angiography was graded. A 6-min walk and a standardized graded Skinner-Gardner exercise treadmill test with peak Vo(2) were performed. A repeated-measures model compared changes over time.

RESULTS

LDL reduction from baseline to year 2 was greater in the simvastatin 40 mg/ezetimibe 10 mg group (116 ± 42 mg/dl to 56 ± 21 mg/dl) than in the simvastatin 40 mg group (129 ± 40 mg/dl to 90 ± 30 mg/dl, p < 0.01). LDL also decreased in the ezetimibe 10 mg group (102 ± 28 mg/dl to 79 ± 27 mg/dl, p < 0.01). Despite this, there was no difference in perfusion, metabolism, or exercise parameters between groups or over time. Resting ABI did improve over time in the ezetimibe 10 mg group and the entire study group of patients.

CONCLUSIONS

Despite effective LDL reduction in PAD, neither tissue perfusion, metabolism, nor exercise parameters improved, although rest ABI did. Thus, LDL lowering does not improve calf muscle physiology or functional capacity in PAD. (Comprehensive Magnetic Resonance of Peripheral Arterial Disease; NCT00587678).

Initial Results of a 12-week, Institution-based, Supervised Exercise Rehabilitation Program for the Management of Peripheral Arterial Disease

This study assessed the effectiveness of a 12-week, institution-based, supervised exercise rehabilitation program with atherogenic risk factor modification in improving cardiovascular profile, ambulatory function, and quality of life of patients with peripheral arterial disease (PAD) by comparing pre- and postprogram measurements. Participants were prospectively enrolled. Cardiovascular profile variables, ambulatory function tests, and quality of life questionnaires were evaluated. Of 101 institution-based program participants, 69 completed the 12-session minimum and 47 completed a postprogram evaluation. Mean postprogram results were significantly different from preprogram results, corresponding to improvement, for the following variables: triglyceride levels ( p = .036), both function tests ( p < .001 for both), four of five Walking Impairment Questionnaire measurements, and Intermittent Claudication Questionnaire score ( p = .001). This supervised exercise program improved the cardiovascular profiles, ambulatory function, and quality of life of PAD patients completing the program and is a viable adjunct to drug therapy and surgical intervention.

Joint torques and powers are reduced during ambulation for both limbs in patients with unilateral claudication

OBJECTIVES

Symptomatic peripheral arterial disease (PAD) results in significant gait impairment. In an attempt to fully delineate and quantify these gait alterations, we analyzed joint kinematics, torques (rotational forces), and powers (rotational forces times angular velocity) in patients with PAD with unilateral claudication for both the affected and nonaffected legs.

METHODS

Twelve patients with unilateral PAD (age, 61.69 +/- 10.53 years, ankle-brachial index [ABI]: affected limb 0.59 +/- 0.25; nonaffected limb 0.93 +/- 0.12) and 10 healthy controls (age, 67.23 +/- 12.67 years, ABI >1.0 all subjects) walked over a force platform to acquire gait kinetics, while joint kinematics were recorded simultaneously. Data were collected for the affected and nonaffected limbs during pain free (PAD-PF) and pain induced (PAD-P) trials. Kinetics and kinematics were combined to quantify torque and powers during the stance period from the hip, knee, and ankle joints.

RESULTS

The affected limb demonstrated significantly (P <.05) reduced ankle plantar flexion torque compared to controls during late stance in both PAD-PF and PAD-P trials. There were significant reductions in ankle plantar flexion power generation during late stance for both the affected (P <.05) and nonaffected limbs (P <.05) compared to control during PAD-PF and PAD-P trials. No significant differences were noted in torque comparing the nonaffected limbs in PAD-PF and PAD-P conditions to control for knee and hip joints throughout the stance phase. Significant reductions were found in knee power absorption in early stance and knee power generation during mid stance for both limbs of the patients with PAD as compared to control (P <.05).

CONCLUSION

Patients with PAD with unilateral claudication demonstrate significant gait impairments in both limbs that are present even before they experience any claudication symptoms. Overall, our data demonstrate significantly reduced ankle plantar flexion torque and power during late stance with reduced knee power during early and mid stance for the affected limb. Further studies are needed to determine if these findings are dependent on the location and the severity of lower extremity ischemia and whether the changes in the nonaffected limb are the result of underlying PAD or compensatory changes from the affected limb dysfunction.

Influence of the Duffy Antigen on Pharmacokinetics and Pharmacodynamics of Recombinant Monocyte Chemoattractant Protein (MCP-1, CCL-2) in Vivo

Monocyte chemoattractant protein-1 (MCP-1, CCL-2) binds to the Duffy antigen (DARC) on red blood cells, which act as a sink for several chemokines including MCP-1. In this study it is hypothesized that DARC may alter the pharmacokinetics of infused recombinant human MCP-1 (rhMCP-1). The primary aim of this first in man trial is to compare the pharmacokinetics of rhMCP-1 in Duffy positive and negative individuals. A randomized, double-blinded, placebo-controlled dose escalation trial was conducted on 36 healthy volunteers. Subjects received infusions of 0.02–2.0 μg/kg rhMCP-1 or placebo for one hour. RhMCP-1 displayed linear pharmacokinetics. Duffy negative individuals reached maximal plasma levels significantly earlier, but overall plasma concentration profiles were not altered. rhMCP-1 markedly increased monocyte counts, and estimated EC50 values were 10-fold higher in Duffy positive than in Duffy negative subjects. Increased monocyte counts were associated with decreased surface expression of intercellular adhesion molecule 1 (ICAM-1, CD54). In contrast, neither CCR-2 or CD11b expression, nor markers of platelet or endothelial activation, inflammation and coagulation were altered. RhMCP-1 is a highly selective chemoattractant for monocytes in humans. The Duffy antigen only minimally alters the pharmacokinetics of rhMCP-1 for doses up to 2 μg/kg.

The role of exercise training in peripheral arterial disease

Peripheral arterial disease (PAD) is currently a major health problem affecting 8-12 million Americans, 15-40% of whom will have intermittent claudication that can lead to substantial impairment in their ability to carry out normal daily activities as well as perform the recommended cardiovascular exercise. Supervised exercise training is an effective tool in the treatment of claudication and is currently a recommended first-line therapy for patients with this condition. In addition to improving pain-free walking distance and quality of life, supervised exercise training can improve many cardiovascular risk factors, possibly reducing the risk for subsequent myocardial infarction, stroke, and death. This paper will review the benefits of supervised exercise training in patients with PAD.