Medical Management of the Patient with Intermittent Claudication

Exercise-Induced Vascular Adaptations under Artificially Versus Pathologically Reduced Blood Flow: A Focus Review with Special Emphasis on Arteriogenesis

Background: The vascular effects of training under blood flow restriction (BFR) in healthy persons can serve as a model for the exercise mechanism in lower extremity arterial disease (LEAD) patients. Both mechanisms are, inter alia, characterized by lower blood flow in the lower limbs. We aimed to describe and compare the underlying mechanism of exercise-induced effects of disease- and external application-BFR methods. Methods: We completed a narrative focus review after systematic literature research. We included only studies on healthy participants or those with LEAD. Both male and female adults were considered eligible. The target intervention was exercise with a reduced blood flow due to disease or external application. Results: We identified 416 publications. After the application of inclusion and exclusion criteria, 39 manuscripts were included in the vascular adaption part. Major mechanisms involving exercise-mediated benefits in treating LEAD included: inflammatory processes suppression, proinflammatory immune cells, improvement of endothelial function, remodeling of skeletal muscle, and additional vascularization (arteriogenesis). Mechanisms resulting from external BFR application included: increased release of anabolic growth factors, stimulated muscle protein synthesis, higher concentrations of heat shock proteins and nitric oxide synthase, lower levels in myostatin, and stimulation of S6K1. Conclusions: A main difference between the two comparators is the venous blood return, which is restricted in BFR but not in LEAD. Major similarities include the overall ischemic situation, the changes in microRNA (miRNA) expression, and the increased production of NOS with their associated arteriogenesis after training with BFR.

Real-life adaptations in walking patterns in patients with established peripheral arterial disease assessed using a global positioning system in the community: a cohort study

OBJECTIVE

Lower extremity peripheral arterial disease (PAD) is a chronic condition most commonly presenting with intermittent claudication (IC). Intermittent claudication limits walking ability and may negatively affect health-related quality of life. Treadmill assessment of maximal walking distance (MWD) is the gold standard to assess PAD symptom severity. Despite being a well-established and reproducible tool, it may be inappropriate (due to frailty or fear) for some patients and only describes maximal abilities for a single walk test. Global positioning systems (GPS) have been proposed as reliable and reproducible tool to measure total, mean and maximal walking distances in patients with PAD, in the community setting. Using GPS, our study attempted to explore what happens to the walking ability of patients with IC following no intervention under 'real-life' conditions.

DESIGN AND METHODS

Using the GlobalSat DG100 GPS, forty-three patients (69 ± 9 years; nine female; no invasive interventions or rehabilitation) undertook two 60-min walking assessments, 6 months apart. Assessments took place in community spaces that had even terrain, no tall trees or buildings and were free from motorized vehicles. Global positioning systems-measured maximum walking distance was the main study outcome measure.

RESULTS

Over the 6-month period, patients demonstrated significantly shorter GPS-measured, mean (552 m versus 334 m; P = 0·02) and maximum (714 m versus 545 m; P = 0·04) walking distances, stopping also more frequently (nine versus five times; P = 0·03).

CONCLUSIONS

Given the reported symptom progression, we advocate early intervention (e.g. exercise interventions) combined with frequent patient monitoring in attempts to maintain or improve walking ability.

Association of lower extremity performance with cardiovascular and all-cause mortality in patients with peripheral artery disease: a systematic review and meta-analysis

Background

Peripheral artery disease (PAD) is associated with impaired mobility and a high rate of mortality. The aim of this systematic review was to investigate whether reduced lower extremity performance was associated with an increased incidence of cardiovascular and all‐cause mortality in people with PAD.

Methods and Results

A systematic search of the MEDLINE, EMBASE, SCOPUS, Web of Science, and Cochrane Library databases was conducted. Studies assessing the association between measures of lower extremity performance and cardiovascular or all‐cause mortality in PAD patients were included. A meta‐analysis was conducted combining data from commonly assessed performance tests. The 10 identified studies assessed lower extremity performance by strength tests, treadmill walking performance, 6‐minute walk, walking velocity, and walking impairment questionnaire (WIQ). A meta‐analysis revealed that shorter maximum walking distance was associated with increased 5‐year cardiovascular (unadjusted RR=2.54, 95% CI 1.86 to 3.47, P<10⁻⁵, n=1577, fixed effects) and all‐cause mortality (unadjusted RR=2.23 95% CI 1.85 to 2.69, P<10⁻⁵, n=1710, fixed effects). Slower 4‐metre walking velocity, a lower WIQ stair‐climbing score, and poor hip extension, knee flexion, and plantar flexion strength were also associated with increased mortality. No significant associations were found for hip flexion strength, WIQ distance score, or WIQ speed score with mortality.

Conclusions

A number of lower extremity performance measures are prognostic markers for mortality in PAD and may be useful clinical tools for identifying patients at higher risk of death. Further studies are needed to determine whether interventions that improve measures of lower extremity performance reduce mortality.

Endovascular treatment for intermittent claudication in patients with peripheral arterial disease: a systematic review

BACKGROUND

We performed a systematic review and meta-analysis to examine whether patients with intermittent claudication can benefit from endovascular treatment (EVT).

METHODS

A prespecified search strategy was used to identify relevant studies in the MEDLINE, Embase, and Cochrane databases. A total of 10 different randomized, controlled trials were reviewed. Random effects meta-analysis was performed between the EVT plus conservative treatment (CT) group and the CT group alone. Also, random effects meta-analysis was performed between the EVT group and the supervised exercise therapy (SET) group.

RESULTS

The independent effect of EVT could directly improve the ankle-brachial index (ABI) and walking performance over the short term, but not over the long term. Moreover, compared to SET, EVT had the superiority in improving the ABI, while SET could improve walking performance more efficiently.

CONCLUSIONS

Patients with intermittent claudication may benefit from endovascular treatment over the short term (within 12 months), with improvements in ABI, intermittent claudication distance, and maximum walking distance. However, considering improvements on walking performance (especially over the long term), SET is recommended.

Phosphodiesterase 5 inhibitor acts as a potent agent sensitizing acute myeloid leukemia cells to 67-kDa laminin receptor-dependent apoptosis

(-)-Epigallocatechin-3-O-gallate (EGCG), a polyphenol in green tea, induces apoptosis in acute myeloid leukemia (AML) cells without affecting normal cells. In this study, we observed that cGMP acts as a cell death mediator of the EGCG-induced anti-AML effect through acid sphingomyelinase activation. EGCG activated the Akt/eNOS axis, a well-known mechanism in vascular cGMP upregulation. We also observed that a major cGMP negative regulator, phosphodiesterase 5, was overexpressed in AML cells, and PDE5 inhibitor, an anti-erectile dysfunction drug, synergistically enhanced the anti-AML effect of EGCG. This combination regimen killed AML cells via overexpressed 67-kDa laminin receptors.