Extracorporeal Shockwave for Intermittent Claudication and Quality of Life: A Randomized Clinical Trial.

Importance: Intermittent lower limb claudication limits function and quality of life. Supervised exercise programs are not readily available, and a noninvasive alternative is needed. Objective: To assess extracorporeal corporeal shockwave therapy in improving quality of life in patients with claudication. Design, Setting, and Participants: In this double-blind, placebo-controlled randomized clinical trial, patients in the outpatient setting at a single tertiary center for vascular surgery were randomized in a 1:1 ratio to extracorporeal shockwave therapy or placebo therapy with no shockwaves delivered. Recruitment was between June 2015 and January 2020, with 12-week follow-up ending in March 2020. A convenience sample of patients with claudication and conservative treatment requirements who refused or were unable to participate in supervised exercise were eligible. Patients receiving anticoagulation therapy or with an active cancer were excluded. Of 522 patients screened, 389 were eligible, 138 were enrolled, and 110 completed follow-up and were included in the primary analysis. Statistical analysis was completed by May 2021. Intervention: In the intervention group, patients received 100 impulses of 0.1mJ/mm/cm2 in an area of the gastrocnemius muscle 3 times weekly for 3 weeks. The steps for treatment were replicated for the control group without delivering the treatment. Main Outcomes and Measures: The primary outcome was the Physical Functioning domain of the 36-item Short-Form Quality of Life Questionnaire at 12-week follow-up. Secondary outcomes included walking distances, ankle brachial pressure index, and other quality-of-life measures. Results: Of 138 patients recruited and randomized, 92 (67%) were male, and the mean (SD) age of the study population was 67 (9.6) years. The intervention group had a significantly higher physical function score at 12 weeks (estimated median difference 3.8; 95% CI, 0.0-7.7; P = .03). However, this significance did not remain when adjusting for covariates. At 12 weeks, the intervention group had significantly longer pain-free and maximum walking distances (pain-free estimated median difference, 34.1, 95% CI, 11.4-56.8; P = .004; maximum estimated median difference, 51.4; 95% CI, 10.7-86.5; P = .01). Conclusions and Relevance: To our knowledge, this is the first double-blind, placebo-controlled, randomized clinical trial to consider extracorporeal shockwave therapy for the management of intermittent claudication. It demonstrated efficacy for walking distances, may have a positive effect on quality of life, and may provide a safe, noninvasive alternative therapy for patients with intermittent claudication. Trial Registration: ClinicalTrials.gov Identifier: NCT02652078.

High INtensity Interval Training in pATiEnts with Intermittent Claudication: A Qualitative Acceptability Study.

BACKGROUND: A novel high-intensity interval training (HIIT) program has demonstrated feasibility for patients with intermittent claudication (IC). The aim of this study was to explore patient perspectives of the HIIT program to inform refinement and future research. METHODS: All patients screened and eligible for the 'high intensity interval training in patients with intermittent claudication (INITIATE)' study were eligible to take part in a semistructured interview. A convenience subsample of patients was selected from 3 distinct groups: 1) those who completed the HIIT program, 2) those who prematurely discontinued the HIIT program, and 3) those who declined the HIIT program. Interviews considered patients views of the program and experiences of undertaking and/or being invited to undertake it. Interviews were audio recorded, transcribed verbatim, and analyzed via thematic analysis. RESULTS: Eleven out of 31 participants who completed the program and 12 out of 38 decliners were interviewed. No participants who withdrew from the program agreed to interview. The 3 key themes were; personal reflections of the program; program facilitators and barriers; and perceived benefits. Completers enjoyed taking part, reported symptomatic improvement and would complete it again. Practical and psychological barriers exist, such as transport and motivation. Changes to the program were suggested. CONCLUSIONS: Findings support the acceptability of this novel HIIT program, which in combination with the feasibility findings, suggest that a fully powered randomized controlled trial, comparing HIIT to usual-care supervised exercise programs is warranted.

Tailored risk assessment and forecasting in intermittent claudication.

BACKGROUND: Guidelines recommend cardiovascular risk reduction and supervised exercise therapy as the first line of treatment in intermittent claudication, but implementation challenges and poor patient compliance lead to significant variation in management and therefore outcomes. The development of a precise risk stratification tool is proposed through a machine-learning algorithm that aims to provide personalized outcome predictions for different management strategies. METHODS: Feature selection was performed using the least absolute shrinkage and selection operator method. The model was developed using a bootstrapped sample based on patients with intermittent claudication from a vascular centre to predict chronic limb-threatening ischaemia, two or more revascularization procedures, major adverse cardiovascular events, and major adverse limb events. Algorithm performance was evaluated using the area under the receiver operating characteristic curve. Calibration curves were generated to assess the consistency between predicted and actual outcomes. Decision curve analysis was employed to evaluate the clinical utility. Validation was performed using a similar dataset. RESULTS: The bootstrapped sample of 10 000 patients was based on 255 patients. The model was validated using a similar sample of 254 patients. The area under the receiver operating characteristic curves for risk of progression to chronic limb-threatening ischaemia at 2 years (0.892), risk of progression to chronic limb-threatening ischaemia at 5 years (0.866), likelihood of major adverse cardiovascular events within 5 years (0.836), likelihood of major adverse limb events within 5 years (0.891), and likelihood of two or more revascularization procedures within 5 years (0.896) demonstrated excellent discrimination. Calibration curves demonstrated good consistency between predicted and actual outcomes and decision curve analysis confirmed clinical utility. Logistic regression yielded slightly lower area under the receiver operating characteristic curves for these outcomes compared with the least absolute shrinkage and selection operator algorithm (0.728, 0.717, 0.746, 0.756, and 0.733 respectively). External calibration curve and decision curve analysis confirmed the reliability and clinical utility of the model, surpassing traditional logistic regression. CONCLUSION: The machine-learning algorithm successfully predicts outcomes for patients with intermittent claudication across various initial treatment strategies, offering potential for improved risk stratification and patient outcomes.

A preoperative supervised exercise program potentially improves long-term survival after elective abdominal aortic aneurysm repair.

OBJECTIVE: A preoperative supervised exercise program (SEP) improves cardiorespiratory fitness and perioperative outcomes for patients undergoing elective abdominal aortic aneurysm (AAA) repair. The aim of this study was to assess the effect of a preoperative SEP on long-term survival of these patients. A secondary aim was to consider long-term changes in cardiorespiratory fitness and quality of life. METHODS: Patients scheduled for open or endovascular AAA repair were previously randomized to either a 6-week preoperative SEP or standard management, and a significant improvement in a composite outcome of cardiac, pulmonary, and renal complications was seen following SEP. For the current analysis, patients were followed up to 5 years post-surgery. The primary outcome for this analysis was all-cause mortality. Data were analyzed on an intention to treat (ITT) and per protocol (PP) basis, with the latter meaning that patients randomized to SEP who did not attend any sessions were excluded. The PP analysis was further interrogated using a complier average causal effect (CACE) analysis on an all or nothing scale, which adjusts for compliance. Additionally, patients who agreed to follow-up attended the research center for cardiopulmonary exercise testing and/or provided quality of life measures. RESULTS: ITT analysis demonstrated that the primary endpoint occurred in 24 of the 124 participants at 5 years, with eight in the SEP group and 16 in the control group (P = .08). The PP analysis demonstrated a significant survival benefit associated with SEP attendance (4 vs 16 deaths; P = .01). CACE analysis confirmed a significant intervention effect (hazard ratio, 0.36; 95% confidence interval, 0.16-0.90; P = .02). There was no difference between groups for cardiorespiratory fitness measures and most quality of life measures. CONCLUSIONS: These novel findings suggest a long-term mortality benefit for patients attending a SEP prior to elective AAA repair. The underlying mechanism remains unknown, and this merits further investigation.

Supervised Exercise Therapy for Intermittent Claudication: A Propensity Score Matched Analysis of Retrospective Data on Long Term Cardiovascular Outcomes.

OBJECTIVE: This study aimed to explore the long term outcomes of patients with intermittent claudication (IC) who completed supervised exercise therapy (SET) vs. those who declined or prematurely discontinued SET, focusing on the incidence of chronic limb threatening ischaemia (CLTI), revascularisation, major adverse limb events (MALE), and major adverse cardiovascular events (MACE). METHODS: A retrospective registry analysis of consecutive patients with IC who were referred for SET between March 2015 and August 2016 and followed up for a minimum of five years. Serial univariable analysis and logistic regression were performed to identify the statistically significant clinical variables that were independent predictors of each outcome measure. The resulting statistically significant variables were used to guide 1:1 propensity score matching (PSM) using the nearest neighbour method with a calliper of 0.2. Cox proportional hazards regression was used to estimate the hazard ratio (HR) and 95% confidence interval (CI) for the association between SET and the outcomes of interest. RESULTS: Two hundred and sixty-six patients were referred to SET between March 2015 and August 2016. Of these, 64 patients completed SET and 202 patients did not. After PSM, 49 patients were analysed in each cohort. The Cox proportional hazards analysis revealed a significant association between completion of SET and revascularisation requirement (HR 0.46 95% CI 0.25 - 0.84; p = .011), completion of SET and progression to CLTI (HR 0.091, 95% CI 0.04 - 0.24; p < .001), completion of SET and MACE (HR 0.52; 95% CI 0.28 - 0.99; p = .05) and completion of SET and MALE (HR 0.28, 95% CI 0.13 - 0.65; p = .003). The Harrell's C index for all of these models was greater than 0.75, indicating good predictive accuracy. CONCLUSION: Completion of SET is associated with better outcomes in patients who completed SET compared with patients who declined or discontinued SET with respect to clinically important cardiovascular outcomes over seven years.

High-intensity interval training in patients with intermittent claudication.

OBJECTIVE: Provision, uptake, adherence, and completion rates for supervised exercise programs (SEP) for intermittent claudication (IC) are low. A shorter, more time-efficient, 6-week, high-intensity interval training (HIIT) program may be an effective alternative that is more acceptable to patients and easier to deliver. The aim of this study was to determine the feasibility of HIIT for patients with IC. METHODS: A single arm proof-of-concept study, performed in secondary care, recruiting patients with IC referred to usual-care SEPs. Supervised HIIT was performed three times per week for 6 weeks. The primary outcome was feasibility and tolerability. Potential efficacy and potential safety were considered, and an integrated qualitative study was undertaken to consider acceptability. RESULTS: A total of 280 patients were screened: 165 (59%) were eligible, and 40 (25%) were recruited. The majority (n = 31; 78%) of participants completed the HIIT program. The remaining nine patients were withdrawn or chose to withdraw. Completers attended 99% of training sessions, completed 85% of sessions in full, and performed 84% of completed intervals at the required intensity. There were no related serious adverse events. Maximum walking distance (+94 m; 95% confidence interval, 66.6-120.8 m) and the SF-36 physical component summary (+2.2; 95% confidence interval, 0.3-4.1) were improved following completion of the program. CONCLUSIONS: Uptake to HIIT was comparable to SEPs in patients with IC, but completion rates were higher. HIIT appears feasible, tolerable, and potentially safe and beneficial for patients with IC. It may provide a more readily deliverable, acceptable form of SEP. Research comparing HIIT with usual-care SEPs appears warranted.

Provision of NICE-recommended varicose vein treatment in the NHS.

BACKGROUND: Standardization of access to treatment and compliance with clinical guidelines are important to ensure the delivery of high-quality care to people with varicose veins. In the National Health Service (NHS) in England, commissioning of care for people with varicose veins is performed by Clinical Commissioning Groups (CCGs) and clinical guidelines have been developed by the National Institute for Health and Care Excellence (NICE CG168). The Evidence-Based Intervention (EBI) programme was introduced in the NHS with the aim of improving care quality and supporting implementation of NICE CG168. The aim of this study was to assess access to varicose vein treatments in the NHS and the impact of EBI. METHODS: CCG policies for the delivery of varicose vein treatments in the NHS in England were obtained from 2017 (before EBI introduction) and 2019 (after EBI introduction) and categorized by two independent reviewers into levels of compliance with NICE CG168. Hospital Episode Statistics data were compared with the NICE commissioning model predictions. A quality-adjusted life-year was valued at £20 000 (Euro 23 000 15 November 2022). RESULTS: Despite the introduction of the EBI programme, CCG compliance with NICE CG168 fell from 34.0 per cent (64 of 191) to 29.0 per cent (55 of 191). Some 33.0 per cent of CCG policies (63 of 191) became less compliant and only 7.3 per cent (14 of 191) changed to become fully compliant. Overall, 66.5 per cent of CCGs (127 of 191) provided less than the recommended intervention rate before EBI and this increased to 73.3 per cent (140 of191) after EBI. The overall proportion of patients estimated to require treatment annually who received treatment fell from 44.0 to 37.0 per cent. The associated estimated loss in net health benefit was between £164 and 174 million (Euro 188 million and 199 million 15 November 2022) over 3 years. A compliant policy was associated with a higher intervention rate; however, commissioning policy was associated with only 16.8 per cent of the variation in intervention rate (R2 = 0.168, P < 0.001). CONCLUSION: Many local varicose vein commissioning policies in the NHS are not compliant with NICE CG168. More than half of patients who should be offered varicose vein treatment are not receiving it, and there is widespread geographical variation. The EBI programme has not been associated with any improvement in commissioning or access to varicose vein treatment.

A systematic review of exercise intervention reporting quality and dose in studies of intermittent claudication.

BACKGROUND: Exercise therapy is an important treatment option for people with intermittent claudication (IC). Appropriate reporting of exercise interventions in populations with IC within randomised controlled trials (RCTs) is important to ensure that research can be translated into clinical practice. Therefore, the purpose of our review is to evaluate the reporting of exercise interventions in RCTs of exercise therapy in patients with IC. METHODS: A systematic search was performed to identify relevant trials in patients with IC published until May 2020. Studies including only participants with critical limb ischaemia or asymptomatic peripheral artery disease were excluded. Each trial was scored using the recently developed 'Consensus on Exercise Reporting Template' (CERT) which has a maximum obtainable score of 19. RESULTS: Of 1489 unique records identified from the search, 73 trials were included, reporting 107 exercise interventions. Overall, the average CERT score was 10/19. The exercise equipment used, the use of supervision and a description of whether the exercise prescription was tailored or generic were the most frequently reported intervention components. The motivational strategies used, intervention adherence and intervention fidelity were the most underreported CERT components. There was no trend indicating that CERT scores were higher in more recent publications. CONCLUSIONS: We have identified that important details about exercise interventions are frequently missing from the published literature. These missing data hinder replication of research findings and limit the translation of evidence into clinical practice.

The Edinburgh Claudication Questionnaire has poor diagnostic accuracy in people with intermittent claudication.

BACKGROUND: The screening and diagnosis of intermittent claudication is a challenging process and often relies on the expertise of specialist vascular clinicians. We sought to investigate the diagnostic performance of the Edinburgh Claudication Questionnaire (ECQ) as a screening tool for referrals of suspected intermittent claudication from primary to secondary care. METHOD: Prospectively, 100 referrals from primary care with a stated diagnosis or query regarding intermittent claudication were recruited. All participants who completed the ECQ, underwent an anklebrachial pressure index (ABPI) assessment and treadmill exercise testing. Outcomes of the ECQ were compared to clinical diagnoses of intermittent claudication. RESULTS: The ECQ had a sensitivity of 46.8% (95% CI: 27-65%), specificity of 63.2% (95% CI: 43-82%) and accuracy of 53.0% (95% CI: 43-63%). The diagnostic performance was not changed by combining the ECQ with a positive ABPI or post-exercise ABPI outcome for PAD. CONCLUSION: The ECQ had a poor diagnostic performance in this cohort. Considering the results found here and in other recent studies, the utility of the ECQ as a screening tool and epidemiological survey tool must be questioned. Novel, low-resource diagnostic tools are needed in this population.

Effects of exercise prescribed at different levels of claudication pain on walking performance in patients with intermittent claudication: a protocol for a randomised controlled trial.

BACKGROUND: Peripheral artery disease affects over 236 million people globally and the classic symptom is intermittent claudication (IC) which is associated with reduction in physical activity. The evidence that supervised exercise programmes (SEPs) improve pain-free and maximal walking distance is irrefutable. However, adherence rates are low with exercise-related pain cited as a contributing factor. National and international guidelines recommend exercising at a moderate to maximal level of claudication pain to improve walking ability; however, exercising pain-free or at mild claudication pain has been shown to achieve this outcome. There is limited evidence that compares the relative effects of exercise prescribed at different levels of claudication pain. OBJECTIVE: The objective of this study is to directly compare the effects of exercise prescribed at three different levels of claudication pain on walking performance. DESIGN: This study will be a single-centre randomised controlled trial. METHODS: Based on an a priori power calculation, 51 patients with IC will be allocated to 24 weeks of twice-weekly pain-free (PF), moderate pain (MOD-P) or maximal pain (MAX-P) exercise. The PF group will cease exercise at the onset of claudication (1 on the 0-4 IC rating scale), the MOD-P group will stop once moderate pain is reached (2 on the rating scale) and the MAX-P group will stop once maximal pain is reached (4 on the rating scale). ANALYSIS: Outcome measures will be assessed at baseline, 12 and 24 weeks adopting an analysis of covariance (ANCOVA) to compare MWD across three time points. The primary outcome for the trial will be change in maximal treadmill walking distance at 12 and 24 weeks. REGISTRATION: Trial registration number: NCT04370327.

Provision of exercise services in patients with peripheral artery disease in the United Kingdom.

OBJECTIVES: Supervised exercise programmes (SEPs) are a vital treatment for people with intermittent claudication, leading improvements in walking distance and quality of life and are recommended in multiple national and international guidelines. We aimed to evaluate the use and structure of SEPs in the United Kingdom (UK). DESIGN: We conducted an anonymous online survey using the Jisc platform comprising of 40 questions. The survey was designed to address key areas such as access, provision, uptake and delivery of SEPs in the United Kingdom. Ethical approval was obtained from Coventry University (P108729). METHODS: The list of trusts providing vascular services was obtained from the National Vascular Registry (NVR) report. The survey was disseminated via social media, The Vascular Society of Great Britain and Ireland and the Society for Vascular Technology. Data were exported to a Microsoft Excel document and analysed using simple descriptive statistics. RESULTS: Of 93 vascular units identified, we received response from 48. Of these, 23 had access to an exercise programme (48%). The majority of SEPs were exclusively for PAD patients (77%), with 21% using integrated services. 67% of respondents were providing a circuit-based programme, and 5 out of 23 were meeting the dose recommendations in the UK National Institute for Health and Care Excellence (NICE) guidelines. Respondents felt that programmes were moderately to extremely important to patients, slightly to very important to clinicians and not at all important to slightly important to commissioning/funding bodies. CONCLUSION: SEPs are a well-established first-line treatment for patients with IC and they are recommended by NICE guidelines. Despite this, many patients still do not have access to an exercise programme, and clinicians do not feel that they have support from commissioning/funding bodies to develop them. There is an urgent need for funding, development and delivery of SEPs in the United Kingdom.

A Systematic Review of Exercise Prescription in Patients with Intermittent Claudication: Does Pain Matter?

BACKGROUND: Current guidelines for intermittent claudication advocate exercise at moderate to maximal claudication pain. However, adherence rates to supervised exercise programmes (SEP) remain poor and claudication pain is a contributing factor. Limited evidence suggests that moderate or pain-free exercise may be just as beneficial and may be better tolerated. However, it remains unclear what 'level' of claudication pain is optimal for improving functional outcomes. We therefore conducted a systematic review to synthesise the evidence for exercise prescribed at different levels of claudication pain. METHODS: The CENTRAL, MEDLINE, Embase and CINAHL databases were searched up to October 2020. Randomized controlled trials (RCTs) that directly compared at least 2 different intensities of claudication pain were included. Outcome measures included walking performance, adherence, quality of life and vascular function. RESULTS: Of 1,543 search results, 2 studies were included. Maximal walking distance improved by 100-128% in the moderate-pain SEP groups, and by 77-90% in the pain-free SEP groups. Importantly, there were no significant differences between the moderate-pain and pain-free SEP groups in either study for improvements in walking performance, though comparison to a maximal-pain SEP group was not made. CONCLUSIONS: The efficacy of SEPs for patients with intermittent claudication is irrefutable, though there is no consensus on the optimal level of pain. Therefore, adequately powered RCTs are required to compare the effect of pain-free SEPs, moderate-pain SEPs and maximal-pain SEPs on functional outcomes. (PROSPERO ID: CRD42020213684).

An updated systematic review and meta-analysis of home-based exercise programs for individuals with intermittent claudication.

OBJECTIVE: Supervised exercise programs (SEP) are effective for improving walking distance in patients with intermittent claudication (IC) but provision and uptake rates are suboptimal. Access to such programs has also been halted by the Coronavirus pandemic. The aim of this review is to provide a comprehensive overview of the evidence for home-based exercise programs (HEP). METHODS: This review was conducted in according with the published protocol and PRISMA guidance. Medline, EMBASE, CINAHL, PEDro, and Cochrane CENTRAL were searched for terms relating to HEP and IC. Randomized and nonrandomized trials that compared HEP with SEP, basic exercise advice, or no exercise controls for IC were included. A narrative synthesis was provided for all studies and meta-analyses conducted using data from randomized trials. The primary outcome was maximal walking distance. Subgroup analyses were performed to consider the effect of monitoring. Risk of bias was assessed using the Cochrane tool and quality of evidence via GRADE. RESULTS: We included 23 studies with 1907 participants. Considering the narrative review, HEPs were inferior to SEPs which was reflected in the meta-analysis (mean distance [MD], 139 m; 95% confidence interval [CI], 45-232 m; P = .004; very low quality of evidence). Monitoring was an important component, because HEPs adopting this strategy were equivalent to SEPs (MD, 8 m; 95% CI, -81 to 97; P = .86; moderate quality of evidence). For HEPs vs basic exercise advice, narrative review suggested HEPs can be superior, although not always significantly so. For HEPs vs no exercise controls, narrative review and meta-analysis suggested HEPs were potentially superior (MD, 136 m; 95% CI, -2 to 273 m; P = .05; very low quality of evidence). Monitoring was also a key element in these comparisons. Other elements such as appropriate frequency (≥3× a week), intensity (to moderate-maximum pain), duration (20 progressing to 60 minutes) and type (walking) of exercise were important, as was education, self-regulation, goal setting, feedback, and action planning. CONCLUSIONS: When SEPs are unavailable, HEPs are recommended. However, to elicit maximum benefit they should be structured, incorporating all elements of our evidence-based recommendations.

A systematic review of exercise testing in patients with intermittent claudication: A focus on test standardisation and reporting quality in randomised controlled trials of exercise interventions.

A systematic review was conducted to identify the range of terminology used in studies to describe maximum walking distance and the exercise testing protocols, and testing modalities used to measure it in patients with intermittent claudication. A secondary aim was to assess the implementation and reporting of the exercise testing protocols. CINAHL, Medline, EMBASE and Cochrane CENTRAL databases were searched. Randomised controlled trials whereby patients with intermittent claudication were randomised to an exercise intervention were included. The terminology used to describe maximal walking distance was recorded, as was the modality and protocol used to measure it. The implementation and reporting quality was also assessed using pre-specified criteria. Sixty-four trials were included in this review. Maximal walking distance was reported using fourteen different terminologies. Twenty-two different treadmill protocols and three different corridor tests were employed to assess maximal walking distance. No single trial satisfied all the implementation and reporting criteria for an exercise testing protocol. Evidence shows that between-study interpretation is difficult given the heterogenous nature of the exercise testing protocols, test endpoints and terminology used to describe maximal walking distance. This is further compounded by poor test reporting and implementation across studies. Comprehensive guidelines need to be provided to enable a standardised approach to exercise testing in patients with intermittent claudication.

Considering the Feasibility, Tolerability, and Safety of High-Intensity Interval Training as a Novel Treatment for Patients With Intermittent Claudication.

PURPOSE: This study assessed the feasibility, tolerability, safety, and potential efficacy of a novel, 6-wk, high-intensity interval training (HIIT) program for patients with intermittent claudication (IC). METHODS: Patients referred to a usual-care supervised exercise program were invited to undertake a HIIT program. All recruited patients performed a baseline cardiopulmonary exercise test (CPX) to inform their exercise prescription. HIIT involved 10, 1-min high-intensity cycling intervals interspersed with 1-min recovery intervals, performed 3 d/wk for 6 wk. Outcomes included feasibility, tolerability, safety, walking distance, and quality of life. RESULTS: A total of 144 patients with IC were referred, 95 met initial eligibility criteria (66%) and 30 (32%) were recruited for HIIT, of which 15 (50%) completed. Of the recruited patients, 90% were on optimal medical therapy and 40% had concomitant cardiac, cerebrovascular, and/or respiratory disease. Patients who completed the program attended 100% of the sessions and one serious adverse event was recorded. Improvements in walking distances and quality of life were observed. Following recruitment of the first 20 patients, the inclusion criteria were refined on the basis of CPX, leading to improved completion rates. CONCLUSIONS: This study provides preliminary findings indicating that patients with IC can complete a short-term HIIT program. We provide very early evidence that HIIT may be safe and well-tolerated. In addition, walking distances seem to improve following HIIT. After a small change in the exclusion criteria, the intervention and inclusion/exclusion criteria now seem appropriate for this population, meaning further research to evaluate HIIT in patients with IC is warranted.

Exercise training for intermittent claudication: a narrative review and summary of guidelines for practitioners.

Peripheral artery disease (PAD) is caused by atherosclerotic narrowing of the arteries supplying the lower limbs often resulting in intermittent claudication, evident as pain or cramping while walking. Supervised exercise training elicits clinically meaningful benefits in walking ability and quality of life. Walking is the modality of exercise with the strongest evidence and is recommended in several national and international guidelines. Alternate forms of exercise such as upper- or lower-body cycling may be used, if required by certain patients, although there is less evidence for these types of programmes. The evidence for progressive resistance training is growing and patients can also engage in strength-based training alongside a walking programme. For those unable to attend a supervised class (strongest evidence), home-based or 'self-facilitated' exercise programmes are known to improve walking distance when compared to simple advice. All exercise programmes, independent of the mode of delivery, should be progressive and individually prescribed where possible, considering disease severity, comorbidities and initial exercise capacity. All patients should aim to accumulate at least 30 min of aerobic activity, at least three times a week, for at least 3 months, ideally in the form of walking exercise to near-maximal claudication pain.

Presurgery exercise-based conditioning interventions (prehabilitation) in adults undergoing lower limb surgery for peripheral arterial disease.

BACKGROUND: Lower limb peripheral arterial disease (PAD) is a type of cardiovascular disease where the blood vessels that carry the blood to the legs are hardened and narrowed. The most severe manifestation of PAD is critical limb ischaemia (CLI). This condition results in symptoms of intractable rest pain, non-healing wounds and ulceration, gangrene or both. PAD affects more than 200 million people worldwide and approximately 3% to 5% of people aged over 40 have PAD, rising to 18% in people over 70 years of age. Between 5% to 10% of symptomatic PAD patients will progress to CLI over a five-year period and the five year cumulative incidence rate for asymptomatic patients with PAD deteriorating to intermittent claudication is 7%, with 21% of these progressing to CLI. Treatment options include angioplasty, bypass or amputation of the limb, when life or limb is threatened. People with CLI have a high risk of mortality and morbidity. The mortality rates during a surgical admission are approximately 5%. Within one year of surgery, the mortality rate rises to 22%. Postoperative complications are as high as 30% and readmission rates vary between 7% to 18% in people with CLI. Despite recent advances in surgical technology, anaesthesia and perioperative care, a proportion of surgical patients have a suboptimal recovery. Presurgery conditioning (prehabilitation) is a multimodal conditioning intervention carried out prior to surgery using a combination of exercise, with or without nutritional or psychological interventions, or both. The use of prehabilitation is gaining momentum, particularly in elderly patients undergoing surgery and patients undergoing colorectal cancer surgery, as a means of optimising fitness to improve the prognosis for people undergoing the physiological stress of surgery. People with PAD are characterised by poor mobility and physical function and have a lower level of fitness as a result of disease progression. Therefore, prehabilitation may be an opportunity to improve their recovery following surgery. However, as multimodal prehabilitation requires considerable resources, it is important to assess whether it is superior to usual care. This review aimed to compare prehabilitation with usual care (defined as a preoperative assessment, including blood and urine tests). The key outcomes were postoperative complications, mortality and readmissions within 30 days of the surgical procedure, and one-year survival rates. OBJECTIVES: To assess the effectiveness of prehabilitation (preoperative exercise, either alone or in combination with nutritional or psychological interventions, or both) on postoperative outcomes in adults with PAD undergoing open lower limb surgery. SEARCH METHODS: The Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register, CENTRAL, MEDLINE, Embase, CINAHL, World Health Organization International Clinical Trials Registry Platform and ClinicalTrials.gov trials register to 25 September 2019. SELECTION CRITERIA: We considered all published and unpublished randomised controlled trials (RCTs) comparing presurgery interventions and usual care. Primary outcomes were postoperative complications, mortality and readmission to hospital within 30 days of the surgical procedure. DATA COLLECTION AND ANALYSIS: Two review authors independently reviewed all records identified by the searches conducted by the Cochrane Vascular Information Specialist. We planned to undertake data collection and analysis in accordance with recommendations described in the Cochrane Handbook for Systematic Reviews of Interventions. MAIN RESULTS: We found no RCTs that met the inclusion criteria for this review. AUTHORS' CONCLUSIONS: We found no RCTs conducted to determine the effects of prehabilitation on mortality or other postoperative outcomes when compared to usual care for patients with PAD. As a consequence, we were unable to provide any evidence to guide the treatment of patients with PAD undergoing surgery. To perform a randomised controlled trial of presurgery conditioning would be challenging but trials are warranted to provide solid evidence on this topic.

High INtensity Interval Training In pATiEnts with intermittent claudication (INITIATE): protocol for a multicentre, proof-of-concept, prospective interventional study.

INTRODUCTION: The first-line recommended treatment for patients with intermittent claudication (IC) is a supervised exercise programme (SEP), which includes a minimum of 2-hours of exercise per week over a 12-week period. However, provision, uptake and adherence rates for these SEP programmes are poor, with time constraints cited as a common participant barrier. High-intensity interval training (HIIT) is more time-efficient and therefore has the potential to overcome this barrier. However, evidence is lacking for the role of HIIT in those with IC. This proof-of-concept study aims to consider the safety, feasibility, tolerability and acceptability of a HIIT programme for patients with IC. METHODS AND ANALYSIS: This multicentre, single-group, prospective, interventional feasibility study will recruit 40 patients with IC, who will complete 6 weeks of HIIT, 3 times a week. HIIT will involve a supervised programme of 10×1 min high-intensity cycling intervals at 85%-90% peak power output (PPO), interspaced with 10×1 min low intensity intervals at 20%-25% PPO. PPO will be determined from a baseline cardiopulmonary exercise test (CPET) and it is intended that patients will achieve ≥85% of maximum heart rate from CPET, by the end of the second HIIT interval. Primary outcome measures are safety (occurrence of adverse events directly related to the study), programme feasibility (including participant eligibility, recruitment and completion rates) and HIIT tolerability (ability to achieve and maintain the required intensity). Secondary outcomes include patient acceptability, walking distance, CPET cardiorespiratory fitness measures and quality of life outcomes. ETHICS AND DISSEMINATION: Ethical approval was obtained via a local National Health Service research ethics committee (Bradford Leeds - 18/YH/0112) and recruitment began in August 2019 and will be completed in October 2020. Results will be published in peer-reviewed journals and presented at international conferences and are expected to inform a future pilot randomised controlled trial of HIIT versus usual-care SEPs. TRIAL REGISTRATION NUMBER: NCT04042311; Pre-results.

Does exercise prescription based on estimated heart rate training zones exceed the ventilatory anaerobic threshold in patients with coronary heart disease undergoing usual-care cardiovascular rehabilitation? A United Kingdom perspective.

BACKGROUND: In the United Kingdom (UK), exercise intensity is prescribed from a fixed percentage range (% heart rate reserve (%HRR)) in cardiac rehabilitation programmes. We aimed to determine the accuracy of this approach by comparing it with an objective, threshold-based approach incorporating the accurate determination of ventilatory anaerobic threshold (VAT). We also aimed to investigate the role of baseline cardiorespiratory fitness status and exercise testing mode dependency (cycle vs. treadmill ergometer) on these relationships. DESIGN AND METHODS: A maximal cardiopulmonary exercise test was conducted on a cycle ergometer or a treadmill before and following usual-care circuit training from two separate cardiac rehabilitation programmes from a single region in the UK. The heart rate corresponding to VAT was compared with current heart rate-based exercise prescription guidelines. RESULTS: We included 112 referred patients (61 years (59-63); body mass index 29 kg·m-2 (29-30); 88% male). There was a significant but relatively weak correlation (r = 0.32; p = 0.001) between measured and predicted %HRR, and values were significantly different from each other (p = 0.005). Within this cohort, we found that 55% of patients had their VAT identified outside of the 40-70% predicted HRR exercise training zone. In the majority of participants (45%), the VAT occurred at an exercise intensity <40% HRR. Moreover, 57% of patients with low levels of cardiorespiratory fitness achieved VAT at <40% HRR, whereas 30% of patients with higher fitness achieved their VAT at >70% HRR. VAT was significantly higher on the treadmill than the cycle ergometer (p < 0.001). CONCLUSION: In the UK, current guidelines for prescribing exercise intensity are based on a fixed percentage range. Our findings indicate that this approach may be inaccurate in a large proportion of patients undertaking cardiac rehabilitation.

A systematic review of high-intensity interval training as an exercise intervention for intermittent claudication.

BACKGROUND: Intermittent claudication (IC) is the most common symptom of peripheral arterial disease, which significantly affects walking ability, functional capacity and quality of life. Supervised exercise programs (SEP) are recommended as first-line treatment, but recruitment and adherence rates are poor. The time required to complete a SEP is the most common barrier to participation cited by patients who decline. High-intensity interval training (HIIT) is more time efficient than current SEPs and therefore has the potential to overcome this barrier. We conducted a systematic review to appraise the evidence for HIIT programs for IC. METHODS: MEDLINE, Embase, and CENTRAL databases were searched for terms related to HIIT and IC. Randomized and nonrandomized trials that investigated HIIT for the treatment of IC were included, with no exclusions based on exercise modality, protocol, or use of a comparator arm. Outcome measures were walking distances, peak oxygen uptake, recruitment and adherence rates, and quality of life. The risk of bias was assessed using the Cochrane tool and study quality using a modified Physiotherapy Evidence Database scale. RESULTS: Nine articles reporting eight studies were included in the review. HIIT seems to improve walking distances and oxygen uptake in relation to controls, with improvements attainable in just 6 weeks. When HIIT was compared with low-intensity exercise, it seemed that longer low-intensity programs were required to obtain similar benefits to those from short-term HIIT. CONCLUSIONS: Initial evidence suggests that HIIT may provide benefits for patients with IC. Initially, pilot studies of low-volume, short-term HIIT vs usual SEPs are required. This strategy will allow for larger randomized, controlled trials to be appropriately designed and adequately powered to further explore the potential benefits of HIIT in IC.