Effects of exercise training in patients with abdominal aortic aneurysm: preliminary results from a randomized trial

The effect of exercise training intervention for patients with abdominal aortic aneurysm on cardiovascular and cardiorespiratory variables: an updated meta-analysis of randomized controlled trials

OBJECTIVE

The purpose of this meta-analysis was to evaluate the effect of exercise training intervention in patients with abdominal aortic aneurysm (AAA).

METHODS

Eight randomized controlled trials (RCTs) that recruited 588 AAA patients were extracted using 4 databases (PubMed, Embase, Wanfang Data, and Cochrane Library). Physiological and biochemistry parameters that included in this study are high-sensitivity C-reactive protein (hs-CRP), respiratory peak oxygen uptake rate (VO2peak), triglyceride (TG), total cholesterol (TC), anaerobic threshold (AT), the diameter of AAA, high density lipoprotein cholesterol (HDL), low density lipoprotein cholesterol (LDL), and matrix metalloproteinase-9 (MMP-9). Standard mean difference (SMD) was used to assess the between group effect.

RESULTS

This meta-analysis was synthesized with findings from RCTs and found that hs-CRP (SMD, - 0.56 mg/dL; 95% CI: - 0.90 to 0.22; P = 0.001), VO2peak (SMD, 0.4 mL/kg/min; 95% CI, 0.21 to 0.60; P < 0.001), TG (SMD, - 0.39 mg/dL; 95% CI: - 0.02 to 0.77; P = 0.04), and AT (SMD, 0.75 mL/kg/min; 95% CI, 0.54 to 0.96; P < 0.001) were significantly improved in the exercise groups, while the size of AAA (SMD, - 0.15; 95% CI: - 0.36 to 0.06; P = 0.15), TC (SMD, 0.16 mg/dL; 95% CI: - 0.10 to 0.42; P = 0.23), HDL/LDL ratio (SMD, - 0.06; 95% CI: - 0.32 to 0.20; P = 0.64), HDL (SMD, - 0.09; 95% CI: - 0.39 to 0.20; P = 0.54), LDL (SMD, 0.08; 95% CI: - 0.21 to 0.38; P = 0.59), and MMP-9 (SMD, - 0.23 mg/dL; 95% CI: - 0.53 to 0.06; P = 0.12) did not differ in the exercise groups compared with the controls.

CONCLUSION

Exercise intervention improved some of the CVD risk factors but not all, hs-CRP, VO2peak and AT were significantly improved after exercise intervention, while, changes of MMP-9, the size of AAA, and the overall lipids profile were not. Exercise intervention provides an additional solution for improving cardiorespiratory capacity and health status among AAA patients, and might lead to a delay of AAA progression.

The impacts of exercise interventions on inflammaging markers in overweight/obesity patients with heart failure: A systematic review and meta-analysis of randomized controlled trials

Objectives

The purpose of this meta-analysis was to investigate the association of aerobic, resistance and concurrent exercises vs. control group on inflammaging markers [tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), IL-1-beta, IL-8, and high sensitivity C-reactive protein (hs-CRP)] in overweight or obesity patients with heart failure (HF).

Methods

The databases of Scopus, PubMed, Web of Science and Google Scholar were searched until August 31, 2022 for exercise interventions vs. control group on circulating inflammaging markers in patients with HF. Only randomized controlled trial (RCT) articles were included. Standardized mean difference (SMD) and 95% confidence intervals (95%CIs) were calculated (registration code = CRD42022347164).

Results

Forty-six full-text articles (57 intervention arms and 3693 participants) were included. A significant reduction was occurred in inflammaging markers of IL-6 [SMD-0.205(95% CI:-0.332 to -0.078),p = 0.002] and hs-CRP [SMD -0.379 (95% CI:-0.556 to -0.202), p = 0.001] with exercise training in patients with HF. Analysis of subgroup by age, body mass index (BMI), type, intensity, duration of exercise and mean left ventricular ejection fraction (LVEF) revealed that there was a significant reduction in TNF-α for middle-aged (p = 0.031), concurrent training (p = 0.033), high intensity (p = 0.005), and heart failure with reduced ejection fraction (HFrEF) (p = 0.007) compared to the control group. There was a significant reduction in IL-6 for middle-aged (p = 0.006), overweight (p = 0.001), aerobic exercise (p = 0.001), both high and moderate intensities (p = 0.037 and p = 0.034), short-term follow-up (p = 0.001), and heart failure with preserved ejection fraction (HFpEF) (p = 0.001) compared to the control group. There was a significant reduction in hs-CRP for middle-aged (p = 0.004), elderly-aged (p = 0.001), overweight (p = 0.001), aerobic exercise (p = 0.001), concurrent training (p = 0.031), both high and moderate intensities (p = 0.017 and p = 0.001), short-term (p = 0.011), long-term (p = 0.049), and very long-term (p = 0.016) follow-ups, HFrEF (p = 0.003) and heart failure with mildly reduced ejection fraction (HFmrEF) (p = 0.048) compared to the control group.

Conclusions

The results confirmed that aerobic exercise and concurrent training interventions were effective to improve inflammaging markers of TNF-α, IL-6, and hs-CRP. These exercise-related anti-inflammaging responses were observed across ages (middle-aged and elderly-aged), exercise intensities, duration of follow-ups, and mean LVEFs (HFrEF, HFmrEF and HFpEF) in overweight patients with HF.

Impacts of Exercise Interventions on Inflammatory Markers and Vascular Adhesion Molecules in Patients With Heart Failure: A Meta-analysis of RCTs

Background

The aim of this meta-analysis was to investigate the effects of concurrent, aerobic, and resistance exercise on markers of inflammation and vascular adhesion molecules (high-sensitivity C-reactive protein [hs-CRP], interleukin [IL]-6, tumour necrosis factor-alpha [TNF-α], soluble intercellular adhesion molecule-1 [sICAM-1], soluble vascular cell adhesion molecule-1 [sVCAM-1], fibrinogen, IL-1-β, IL-10, IL-18, and E-selectin) in patients with heart failure (HF).

Methods

The PubMed, Scopus, Web of Science, and Google Scholar databases were searched for dates up to August 31, 2022. Randomized controlled trial studies for exercise interventions on circulating inflammatory and vascular adhesion markers in patients with HF were included. Standardized mean difference (SMD) and 95% confidence interval (CI) were calculated.

Results

A total of 45 articles were included. Exercise training significantly reduced hs-CRP (SMD -0.441 [95% CI: -0.642 to -0.240], P = 0.001), IL-6 (SMD -0.158 (95% CI: -0.303 to -0.013], P = 0.032), and sICAM-1 (SMD -0.282 [95% CI: -0.477 to -0.086], P = 0.005) markers. Analysis of subgroups revealed that a significant reduction occurred in hs-CRP level for the following subgroups: middle-aged, elderly, overweight status, aerobic exercise, concurrent training, both high and moderate intensity, and short-term, long-term, and very long-term follow-up, compared to a control group (P < 0.05). A significant reduction occurred in IL-6 and sICAM-1 levels for those in the following subgroups, compared to a control group (P < 0.05): middle-aged, aerobic exercise, moderate-intensity exercise, and short-term follow-up. A reduction in TNF-α level occurred for middle-aged patients, compared to a control-group (P < 0.05).

Conclusions

These exercise-related changes (improved inflammation and vascular adhesion markers) as clinical benefits in general, and for exercise-based cardiac rehabilitation in a more-specific format, improve clinical evolution and survival in patients with HF of different etiologies (registration number = CRD42021271423).

Editor's Choice - The Abdominal Aortic Aneurysm Get Fit Trial: A Randomised Controlled Trial of Exercise to Improve Fitness in Patients with Abdominal Aortic Aneurysm

OBJECTIVE

Ruptured abdominal aortic aneurysm (AAA) carries a mortality rate of up to 80%. Elective repair prevents rupture, but peri-operative mortality remains at 2% - 3%. This mortality rate and long term survival rate are associated with impaired peak oxygen uptake (peak VO₂), oxygen uptake at anaerobic threshold (AT) and ventilatory equivalent for CO₂ (VECO₂) at AT on cardiopulmonary exercise testing (CPET). Improving fitness to optimise these variables could improve peri-operative and long term survival, but the required exercise training suitable for patients with AAA has yet to be established. This randomised controlled trial aimed to evaluate the effectiveness of 24 week, patient directed, community based exercise on CPET measured fitness in AAA surveillance patients.

METHODS

This was a prospective randomised controlled trial in a tertiary UK vascular centre conducted using CONSORT guidelines. Patients on AAA surveillance (n = 56) were randomly assigned to either (1) a 24 week community exercise programme (CEP) with choice of gym or home exercises, or (2) standard clinical care including advice on weight loss and exercise. The primary outcome was change in peak VO₂ at 24 weeks, with secondary outcomes including AT, VECO₂, cardiovascular biomarkers (lipid profile, pro-B-type natriuretic peptide, and high sensitivity C reactive protein, body mass index, and HRQoL. Follow up was at eight, 16, 24, and 36 weeks to evaluate duration of benefit. All analyses were performed on an intention to treat basis.

RESULTS

CEP patients (n = 28) achieved mean (95% confidence interval [CI]) improvements from baseline in peak VO₂ of 1.5 (95% CI 0.5 - 2.5), 2.1 (95% CI 1.1 - 3.2), 2.3 (95% CI 1.2 - 3.3), and 2.2 (95% CI 1.1, 3.3) mL/kg/min at 8, 16, 24, and 36 weeks, respectively. These changes in CEP patients were significantly greater than those seen in control patients at 16 (p = .002), 24 (p = .031), and 36 weeks (p < .001). There were also significant improvements in AT, triglyceride levels, and HRQoL in CEP patients.

CONCLUSION

This CEP significantly improved those CPET parameters associated with impaired peri-operative and long term survival in patients following AAA repair. These improvements were maintained at 12 weeks following the end of the programme.

Prehabilitation for Vascular Surgery Patients: Challenges and Opportunities

Global demand for major surgery is rising as a consequence of a growing, ageing population and clinically applicable approaches to perioperative risk reduction have never been needed more. Prehabilitation aims to optimise aerobic capacity and address modifiable risk factors prior to surgery to improve postoperative outcomes. Given the inherently high-risk nature of vascular surgery and the frequently high-acuity, frail, vascular surgical population, the potential to introduce an intervention into the surgical pathway that may reduce postoperative complications cannot be overlooked. The aim of this article is to examine the current evidence base for prehabilitation in patients awaiting vascular surgery, and to summarise the potential benefits, pitfalls, and practicalities of this emerging perioperative intervention. There is a paucity of high-quality research specifically aimed at prehabilitation for patients undergoing vascular surgery, both peripheral and aortic, making it difficult to draw definitive conclusions upon which to base a change in practice. Currently, evidence is taken from small, often single-centre heterogenous studies that vary significantly from each other, meaning that the optimal exercise regimen for patients awaiting vascular surgery has yet to be defined. Establishing the impact of prehabilitation on outcomes for vascular patients is important as the effectiveness of preoperative exercise training is likely to vary between surgical interventions and patient populations. However, extrapolation from other cohorts is possible and indeed forms the basis of many current prehabilitation programmes. Given the success of prehabilitation in other surgical groups, it has potential to become an important future research target for patients awaiting vascular surgery.

ARTP statement on cardiopulmonary exercise testing 2021

Cardiopulmonary exercise testing (CPET) has become an invaluable tool in healthcare, improving the diagnosis of disease and the quality, efficacy, assessment and safety of treatment across a range of pathologies. CPET's superior ability to measure the global exercise response of the respiratory, cardiovascular and skeletal muscle systems simultaneously in a time and cost-efficient manner has led to the application of CPET in a range of settings from diagnosis of disease to preoperative assessment. The Association for Respiratory Technology and Physiology Statement on Cardiopulmonary Exercise Testing 2021 provides the practitioner and scientist with an outstanding resource to support and enhance practice, from equipment to testing to leadership, helping them deliver a quality assured service for the benefit of all patient groups.

Prehabilitation exercise therapy before elective abdominal aortic aneurysm repair

BACKGROUND

An abdominal aortic aneurysm (AAA) is an abnormal dilation in the diameter of the abdominal aorta of 50% or more of the normal diameter or greater than 3 cm in total. The risk of rupture increases with the diameter of the aneurysm, particularly above a diameter of approximately 5.5 cm. Perioperative and postoperative morbidity is common following elective repair in people with AAA. Prehabilitation or preoperative exercise is the process of enhancing an individual's functional capacity before surgery to improve postoperative outcomes. Studies have evaluated exercise interventions for people waiting for AAA repair, but the results of these studies are conflicting.

OBJECTIVES

To assess the effects of exercise programmes on perioperative and postoperative morbidity and mortality associated with elective abdominal aortic aneurysm repair.

SEARCH METHODS

We searched the Cochrane Vascular Specialised register, Cochrane Central Register of Controlled Trials, MEDLINE, Embase, CINAHL (Cumulative Index to Nursing and Allied Health Literature), and Physiotherapy Evidence Database (PEDro) databases, and the World Health Organization International Clinical Trials Registry Platform and ClinicalTrials.gov trials registers to 6 July 2020. We also examined the included study reports' bibliographies to identify other relevant articles.

SELECTION CRITERIA

We considered randomised controlled trials (RCTs) examining exercise interventions compared with usual care (no exercise; participants maintained normal physical activity) for people waiting for AAA repair.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected studies for inclusion, assessed the included studies, extracted data and resolved disagreements by discussion. We assessed the methodological quality of studies using the Cochrane risk of bias tool and collected results related to the outcomes of interest: post-AAA repair mortality; perioperative and postoperative complications; length of intensive care unit (ICU) stay; length of hospital stay; number of days on a ventilator; change in aneurysm size pre- and post-exercise; and quality of life. We used GRADE to evaluate certainty of the evidence. For dichotomous outcomes, we calculated the risk ratio (RR) with the corresponding 95% confidence interval (CI).

MAIN RESULTS

This review identified four RCTs with a total of 232 participants with clinically diagnosed AAA deemed suitable for elective intervention, comparing prehabilitation exercise therapy with usual care (no exercise). The prehabilitation exercise therapy was supervised and hospital-based in three of the four included trials, and in the remaining trial the first session was supervised in hospital, but subsequent sessions were completed unsupervised in the participants' homes. The dose and schedule of the prehabilitation exercise therapy varied across the trials with three to six sessions per week and a duration of one hour per session for a period of one to six weeks. The types of exercise therapy included circuit training, moderate-intensity continuous exercise and high-intensity interval training. All trials were at a high risk of bias. The certainty of the evidence for each of our outcomes was low to very low. We downgraded the certainty of the evidence because of risk of bias and imprecision (small sample sizes). Overall, we are uncertain whether prehabilitation exercise compared to usual care (no exercise) reduces the occurrence of 30-day (or longer if reported) mortality post-AAA repair (RR 1.33, 95% CI 0.31 to 5.77; 3 trials, 192 participants; very low-certainty evidence). Compared to usual care (no exercise), prehabilitation exercise may decrease the occurrence of cardiac complications (RR 0.36, 95% CI 0.14 to 0.92; 1 trial, 124 participants; low-certainty evidence) and the occurrence of renal complications (RR 0.31, 95% CI 0.11 to 0.88; 1 trial, 124 participants; low-certainty evidence). We are uncertain whether prehabilitation exercise, compared to usual care (no exercise), decreases the occurrence of pulmonary complications (RR 0.49, 95% 0.26 to 0.92; 2 trials, 144 participants; very low-certainty evidence), decreases the need for re-intervention (RR 1.29, 95% 0.33 to 4.96; 2 trials, 144 participants; very low-certainty evidence) or decreases postoperative bleeding (RR 0.57, 95% CI 0.18 to 1.80; 1 trial, 124 participants; very low-certainty evidence). There was little or no difference between the exercise and usual care (no exercise) groups in length of ICU stay, length of hospital stay and quality of life. None of the studies reported data for the number of days on a ventilator and change in aneurysm size pre- and post-exercise outcomes.

AUTHORS' CONCLUSIONS

Due to very low-certainty evidence, we are uncertain whether prehabilitation exercise therapy reduces 30-day mortality, pulmonary complications, need for re-intervention or postoperative bleeding. Prehabilitation exercise therapy might slightly reduce cardiac and renal complications compared with usual care (no exercise). More RCTs of high methodological quality, with large sample sizes and long-term follow-up, are needed. Important questions should include the type and cost-effectiveness of exercise programmes, the minimum number of sessions and programme duration needed to effect clinically important benefits, and which groups of participants and types of repair benefit most.

Prehabilitation Coming of Age: IMPLICATIONS FOR CARDIAC AND PULMONARY REHABILITATION

While cardiac and pulmonary rehabilitation programs traditionally involve exercise therapy and risk management following an event (eg, myocardial infarction and stroke), or an intervention (eg, coronary artery bypass surgery and percutaneous coronary intervention), prehabilitation involves enhancing functional capacity and optimizing risk profile prior to a scheduled intervention. The concept of prehabilitation is based on the principle that patients with higher functional capabilities will better tolerate an intervention, and will have better pre- and post-surgical outcomes. In addition to improving fitness, prehabilitation has been extended to include multifactorial risk intervention prior to surgery, including psychosocial counseling, smoking cessation, diabetes control, nutrition counseling, and alcohol abstinence. A growing number of studies have shown that patients enrolled in prehabilitation programs have reduced post-operative complications and demonstrate better functional, psychosocial, and surgery-related outcomes. These studies have included interventions such as hepatic transplantation, lung cancer resection, and abdominal aortic aneurysm (repair, upper gastrointestinal surgery, bariatric surgery, and coronary artery bypass grafting). Studies have also suggested that incorporation of prehabilitation before an intervention in addition to traditional rehabilitation following an intervention further enhances physical function, lowers risk for adverse events, and better prepares a patient to resume normal activities, including return to work. In this overview, we discuss prehabilitation coming of age, including key elements related to optimizing pre-surgical fitness, factors to consider in developing a prehabilitation program, and exercise training strategies to improve pre-surgical fitness.

Effects of Exercise Training on Vascular Markers of Disease Progression in Patients with Small Abdominal Aortic Aneurysms

BACKGROUND

Currently, no medical therapy is effective in limiting progression of small abdominal aortic aneurysms (AAA; ≤5.5 cm). Previously, we have demonstrated safety and efficacy of exercise training in patients with AAA. However, the impact of exercise training on vascular markers of AAA progression, such as lipid accumulation product and matrix metalloproteinase 9 (MMP-9, linked to destruction of aortic matrix), is unknown. The aim of this study was to assess the impact of exercise training on AAA diameter, lipid accumulation product, MMP-9, and other risk markers of vascular disease.

METHODS

In this randomized trial, complete data of 96 patients (male: n = 87, female: n = 9; exercise training (exercise) n = 42, usual care n = 54) were studied. Changes in AAA diameter, exercise capacity, lipid accumulation product (men = [waist circumference 65] × fasting triglycerides; women = [waist circumference -58] × triglycerides) and MMP-9 were performed.

RESULTS

The exercise group demonstrated a significant increase in maximal exercise time and estimated metabolic equivalent of tasks. Lipid accumulation product decreased in exercise and increased in usual care (P < .001 between groups); MMP-9 remained statistically unchanged in exercise, but increased significantly in usual care (P = .005; between groups P = .094). In both groups, there was a significant increase in transverse diameter, but no difference between groups; neither group assignment nor level of fitness correlated with AAA enlargement. No adverse clinical events occurred.

CONCLUSIONS

This is the first study to demonstrate that in AAA, exercise beneficially modifies lipid accumulation product and MMP-9, both markers of vascular disease, without inducing aneurysmal growth beyond what is otherwise observed during usual care.

Background and Proposed Design for a Metformin Abdominal Aortic Aneurysm Suppression Trial

Abdominal aortic aneurysm (AAA) may lead to rupture and death if left untreated. While endovascular or surgical repair is generally recommended for AAA greater than 5–5.5 cm, the vast majority of aneurysms detected by screening modalities are smaller than this threshold. Once discovered, there would be a significant potential benefit in suppressing the growth of these small aneurysms in order to obviate the need for repair and mitigate rupture risk. Patients with diabetes, in particular those taking the oral hypoglycaemic medication metformin, have been shown to have lower incidence, growth rate, and rupture risk of AAA. Metformin therefore represents a widely available, non-toxic, potential inhibitor of AAA growth, but thus far no prospective clinical studies have evaluated this. Here, we present the background, rationale, and design for a randomised, double-blind, placebo-controlled clinical trial of metformin for growth suppression in patients with small AAA.

Surgery for small asymptomatic abdominal aortic aneurysms

BACKGROUND

An abdominal aortic aneurysm (AAA) is an abnormal ballooning of the major abdominal artery. Some AAAs present as emergencies and require surgery; others remain asymptomatic. Treatment of asymptomatic AAAs depends on many factors, but the size of the aneurysm is important, as risk of rupture increases with aneurysm size. Large asymptomatic AAAs (greater than 5.5 cm in diameter) are usually repaired surgically; very small AAAs (less than 4.0 cm diameter) are monitored with ultrasonography. Debate continues over the roles of early repair versus surveillance with repair on subsequent enlargement in people with asymptomatic AAAs of 4.0 cm to 5.5 cm diameter. This is the fourth update of the review first published in 1999.

OBJECTIVES

To compare mortality and costs, as well as quality of life and aneurysm rupture as secondary outcomes, following early surgical repair versus routine ultrasound surveillance in people with asymptomatic AAAs between 4.0 cm and 5.5 cm in diameter.

SEARCH METHODS

The Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register, CENTRAL, MEDLINE, two other databases, and two trials registers to 10 July 2019. We handsearched conference proceedings and checked reference lists of relevant studies.

SELECTION CRITERIA

We included randomised controlled trials where people with asymptomatic AAAs of 4.0 cm to 5.5 cm were randomly allocated to early repair or imaging-based surveillance at least every six months. Outcomes had to include mortality or survival.

DATA COLLECTION AND ANALYSIS

Three review authors independently extracted data, which were cross-checked by other team members. Outcomes were mortality, costs, quality of life, and aneurysm rupture. For mortality, we estimated risk ratios (RR) (endovascular aneurysm repair only), hazard ratios (HR) (open repair only), and 95% confidence intervals (CI) based on Mantel-Haenszel Chi² statistics at one and six years (open repair only) following randomisation.

MAIN RESULTS

We found no new studies for this update. Four trials with 3314 participants fulfilled the inclusion criteria. Two trials compared early open repair with surveillance and two trials compared early endovascular repair (EVAR) with surveillance. We used GRADE to access the certainty of the evidence for mortality and cost, which ranged from high to low. We downgraded the certainty in the evidence from high to moderate and low due to risk of bias concerns and imprecision (some outcomes were only reported by one study). All four trials showed an early survival benefit in the surveillance group (due to 30-day operative mortality with repair) but no evidence of differences in long-term survival. One study compared early open repair with surveillance with an adjusted HR of 0.88 (95% CI 0.75 to 1.02, mean follow-up 10 years; HR 1.21, 95% CI 0.95 to 1.54, mean follow-up 4.9 years). Pooled analysis of participant-level data from the two trials comparing early open repair with surveillance (maximum follow-up seven to eight years) showed no evidence of a difference in survival (propensity score-adjusted HR 0.99, 95% CI 0.83 to 1.18; 2226 participants; high-certainty evidence). This lack of treatment effect did not vary to three years by AAA diameter (P = 0.39), participant age (P = 0.61), or for women (HR 0.84, 95% CI 0.62 to 1.11). Two studies compared EVAR with surveillance and there was no evidence of a survival benefit for early EVAR at 12 months (RR 1.92, 95% CI 0.73 to 5.06; 846 participants; low-certainty evidence). Two trials reported costs. The mean UK health service costs per participant over the first 18 months after randomisation were higher in the open repair surgery than the surveillance group (GBP 4978 in the repair group versus GBP 3914 in the surveillance group; mean difference (MD) GBP 1064, 95% CI 796 to 1332; 1090 participants; moderate-certainty evidence). There was a similar difference after 12 years. The mean USA hospital costs for participants at six months after randomisation were higher in the EVAR group than in the surveillance group (USD 33,471 with repair versus USD 5520 with surveillance; MD USD 27,951, 95% CI 25,156 to 30,746; 614 participants; low-certainty evidence). After four years, there was no evidence of a difference in total medical costs between groups (USD 48,669 with repair versus USD 46,112 with surveillance; MD USD 2557, 95% CI -8043 to 13,156; 614 participants; low-certainty evidence). All studies reported quality of life but used different assessment measurements and results were conflicting. All four studies reported aneurysm rupture. There were very few ruptures reported in the trials of EVAR versus surveillance up to three years. In the trials of open surgery versus surveillance, there were ruptures to at least six years and there were more ruptures in the surveillance group, but most of these ruptures occurred in aneurysms that had exceeded the threshold for surgical repair.

AUTHORS' CONCLUSIONS

There was no evidence of an advantage to early repair for small AAA (4.0 cm to 5.5 cm), regardless of whether open repair or EVAR is used and, at least for open repair, regardless of patient age and AAA diameter. Thus, neither early open nor early EVAR of small AAAs is supported by currently available evidence. Long-term data from the two trials investigating EVAR are not available, so, we can only draw firm conclusions regarding outcomes after the first few years for open repair. Research regarding the risks related to and management of small AAAs in ethnic minorities and women is urgently needed, as data regarding these populations are lacking.

Effectiveness and safety of structured exercise vs. no exercise for asymptomatic aortic aneurysm: systematic review and meta-analysis

We conducted a systematic review to compare the effectiveness and safety of exercise versus no exercise for patients with asymptomatic aortic aneurysm. We followed the guidelines set out in the Cochrane systematic review handbook. We searched Medline, Embase, CENTRAL, LILACS, PeDRO, CINAHL, clinicaltrials.gov, ICTRP, and OpenGrey using the MeSH terms “aortic aneurysm” and “exercise”. 1189 references were identified. Five clinical trials were included. No exercise-related deaths or aortic ruptures occurred in these trials. Exercise did not reduce the aneurysm expansion rate at 12 weeks to 12 months (mean difference [MD], −0.05; 95% confidence interval [CI], −0.13 to 0.03). Six weeks of preoperative exercise reduced severe renal and cardiac complications (risk ratio, 0.54; 95% CI, 0.31–0.93) and the length of intensive care unit stay (MD, −1.00; 95% CI, −1.26 to −0.74). Preoperative and postoperative forward walking reduced the length of hospital stay (MD, −0.69; 95% CI, −1.24 to −0.14). The evidence was graded as ‘very low’ level.

Exercise Training Improves Ventilatory Efficiency in Patients With a Small Abdominal Aortic Aneurysm: A RANDOMIZED CONTROLLED STUDY

PURPOSE

To investigate the effects of exercise training on ventilatory efficiency and physiological responses to submaximal exercise in subjects with small abdominal aortic aneurysm (AAA).

METHODS

Sixty-five male patients (72.3 ± 7.0 years) were randomized to exercise training (n = 33) or usual care group (n = 32). Exercise subjects participated in a training groups for 3 mo. Cardiopulmonary exercise testing was performed before and after the study period and peak (Equation is included in full-text article.)O2, the ventilatory threshold (VT), the oxygen uptake efficiency slope (OUES), and the (Equation is included in full-text article.)E2/(Equation is included in full-text article.)CO2 slope were identified. Baseline work rates at VT were matched to examine cardiopulmonary responses after training.

RESULTS

Significant interactions indicating improvements before and after training in the exercise group were noted for time (P < .01), (Equation is included in full-text article.)O2 (P < .01), and work rate (P < .01) at the VT. At peak effort, significant interactions were noted for time (P < .01) and work rate (P < .01), while borderline significance was noted for absolute (P = .07) and relative (P = .04) (Equation is included in full-text article.)O2. Significant interactions were observed for the OUES both when using all exercise data (P = .04) and when calculated up to the VT (P < .01). For the (Equation is included in full-text article.)E2/(Equation is included in full-text article.)CO2 slope, significance was noted only when calculated up to the VT (P = .04). After training, heart rate, (Equation is included in full-text article.)E, (Equation is included in full-text article.)O2 and respiratory exchange ratio were significantly attenuated for the same baseline work rate only in the exercise group (all P < .01).

CONCLUSIONS

Exercise training improves ventilatory efficiency in patients with small AAA. In addition, patients who exercised exhibited less demanding cardiorespiratory responses to submaximal effort.

Comprehensive Cardiac Rehabilitation as a Therapeutic Strategy for Abdominal Aortic Aneurysm

Abdominal aortic aneurysms (AAA) are referred to as “time bombs”. The only way to prevent AAA rupture is elective repair beforehand using surgical replacement or an endovascular procedure. Non-surgical strategies to prevent AAA expansion are under intense investigation. At each AAA stage, that is, occurrence, expansion, and rupture, the mechanisms and risk factors are different, as discussed in this review. Based on the mechanism and risk factors for AAA expansion, the most effective strategy against AAA expansion need to be identified, but so far none has. Exercise is known to be essential for preventing atherosclerosis related to the coexistence of AAA and CAD, but some doctors are hesitant to prescribe exercise programs to AAA patients given that BP elevation during exercise can cause AAA expansion or rupture. In our retrospective study and prospective study on the safety and effectiveness of exercise for AAA patients, the protective role of mild-moderate exercise against expansion of small AAA was clearly shown. The stability of AAA on exercise might be related to reduced inflammatory activity in the aortic wall, stabilized elevation in BP during exercise, increased aortic blood flow, upregulation of transforming growth factor-β1, moderated BMI and/or fat, or improved endothelial function. Until a revolutionary drug emerges that can regress AAA, cardiac rehabilitation remains the best strategy for preventing AAA expansion and rupture.

A systematic review of the impact of preoperative exercise for patients with abdominal aortic aneurysm

BACKGROUND

Abdominal aortic aneurysm (AAA) surgery carries significant risk of morbidity and mortality. Preoperative exercise may improve the physical fitness capacity of patients with AAA as well as postoperative outcomes.

METHODS

A systematic review was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. An electronic search was performed on MEDLINE, Embase, and Cochrane Library for relevant studies. A methodologic assessment of included studies was conducted using the Physiotherapy Evidence Database (PEDro) scale.

RESULTS

Seven studies (six randomized controlled trials and one retrospective cohort study) were included. The overall quality of studies was assessed to range from fair to good. Three studies included AAA patients without indication for surgery, whereas four other studies included AAA patients awaiting surgical repair. One study implemented an inspiratory muscle training program; five studies implemented a continuous moderate-intensity exercise regimen; one study implemented a high-intensity interval training program. Overall compliance with the exercise regimen was high (94% in those not waiting for surgery; 75.8% to 82.3% in those waiting for surgery). In patients not awaiting surgery, preoperative exercise may improve physical fitness parameters including ventilatory threshold (P = .016 at 12 weeks; P = .09 at 12 months) and anaerobic threshold (10% increase; P = .007) but not peak oxygen consumption (P = .183 at 12 weeks; P = .29 at 12 months). In patients awaiting surgery, one study demonstrated a statistically significant improvement in peak oxygen consumption (difference, 1.6 mL/kg/min; P = .004) and anaerobic threshold (difference, 1.9 mL/kg/min; P = .012) for patients who exercised. In terms of postoperative outcomes, exercise may reduce the risk of cardiac, renal, and respiratory complications, although only in those who undergo open surgery. Only patients who underwent endovascular repair had a shorter length of hospital stay when preoperative exercise was conducted.

CONCLUSIONS

Despite the encouraging evidence of preoperative exercise for AAA patients, it remains premature to recommend it as a preoperative intervention. Given the heterogeneity of reported outcomes, future studies should consider conducting well-designed randomized controlled trials with standardized reporting outcomes and definitions.

Meta-analysis of randomized controlled trials on safety and efficacy of exercise training in patients with abdominal aortic aneurysm

OBJECTIVE

Low exercise capacity preoperatively leads to increased postoperative complications, perioperative mortality, length of stay, and inpatient costs among patients going through elective abdominal aortic aneurysm (AAA) surgery. Therefore, exercise training may be extremely important for reducing perioperative adverse events in AAA patients. This paper aimed to perform a meta-analysis of randomized controlled trials to evaluate the safety of exercise training and its effects on exercise capacity in AAA patients.

METHODS

We searched for randomized controlled trials published up to December 2017 that compared exercise training vs usual care without exercise training in AAA patients. The primary outcome was safety, specifically the occurrence of cardiovascular adverse events during the study. Secondary outcomes were changes in AAA diameter, inflammation markers, and exercise capacity based on peak oxygen consumption (peak V˙o₂) and anaerobic threshold (AT).

RESULTS

We identified 341 trials, and after an assessment of relevance, 7 trials with a combined total of 489 participants were analyzed. There were a total of two cardiovascular adverse events during the exercise test and training, and the cardiovascular event rate and its 95% confidence interval (CI) were 0.8% and 0.2% to 3.1%. Exercise training did not tend to increase AAA diameter, and it also tended to decrease high-sensitivity C-reactive protein level in patients with AAA. All studies that evaluated the changes in AAA diameter or high-sensitivity C-reactive protein level involved patients with AAA diameter <55 mm at baseline; there was no study involving participants with AAA diameter ≥55 mm at baseline. Exercise training significantly increased peak V˙o₂ (pooled mean difference, 1.67 mL/kg/min; 95% CI, 0.69-2.65; P < .001) and AT (pooled mean difference, 1.98 mL/kg/min; 95% CI, 0.77-3.19; P < .001) in AAA patients. The result of meta-regression suggested that the effects of exercise training on peak V˙o₂ and AT were not modulated by the exercise duration.

CONCLUSIONS

Our analyses suggested that exercise training among AAA patients is generally safe, although future research should be carried out to further clarify the safety among patients with large AAAs. Exercise training improved peak V˙o₂ and AT in AAA patients. More data are required to identify the optimal exercise duration for improving exercise capacity in patients with AAA.

Mobilization of the lumbar spine in a 76-year-old male with mechanical low back pain and an abdominal aortic aneurysm: A case report

BACKGROUND

Abdominal aortic aneurysms (AAAs) are found in 1-12% of older males. Low back pain (LBP) is prevalent with incidence increasing with age and can respond to manual therapy (MT). To date, the safety of the application of MT for LBP in the presence of a known AAA has not been reported. This case reports on the short-term effects of MT in a patient with LBP and AAA and pre- and post-therapy imaging.

CASE DESCRIPTION

A 76-year-old male presented with mechanical LBP, groin pain, and a known 4.2-cm AAA. A lumbar magnetic resonance imaging showed significant multilevel abnormalities. Abdominal screening did not elicit back or groin pain. Lumbar and hip range of motion and accessory motion testing reproduced his complaints. He was treated with lumbar and hip MT.

OUTCOMES

After three visits, he reported that his groin pain resolved, and his back pain could be managed with home exercise. He reported a +6 on the global rating of change. Repeated follow-up imaging of his AAA demonstrated no significant change of his AAA.

DISCUSSION

No immediate adverse events were recorded, and repeated follow-up imaging indicated no significant AAA expansion. Considering that mobilization causes similar displacement to active motion, research into the safety of MT in this population is warranted as are guidelines for appropriate initial and ongoing clinical screening during treatment in this population.

Cardiac Rehabilitation Protects Against the Expansion of Abdominal Aortic Aneurysm

Background

Virtually no reports on the effects of exercise in patients with a small abdominal aortic aneurysm (AAA) exist.

Methods and Results

We conducted a retrospective cohort study on 1515 patients with a small AAA before surgery at 2 high‐volume hospitals in Tokyo, Japan, from April 2004 to September 2015. A carefully modified cardiac rehabilitation program without excessive blood pressure elevation during exercise was prescribed to 50 patients with an AAA. Using propensity score matching, mortality and clinical outcomes, including AAA expansion rate, were compared between 2 groups: rehabilitation group and nonrehabilitation group. The background characteristics of the rehabilitation group (n=49) and the nonrehabilitation group (n=163) were almost identical. The risk for AAA repair was much lower in the rehabilitation group after matching (before matching: hazard ratio, 0.43; 95% confidence interval, 0.25–0.72; P=0.001; and after matching: hazard ratio, 0.19; 95% confidence interval, 0.07–0.50; P<0.001). AAA expansion rate was slower in the rehabilitation group (before matching: rehabilitation versus nonrehabilitation group, 2.3±3.7 versus 3.8±3.4 mm/y [P=0.008]; after matching: rehabilitation versus nonrehabilitation group, 2.1±3.0 versus 4.5±4.0 mm/y [P<0.001]). Elevation of blood pressure during exercise was positively correlated with AAA expansion rate after the rehabilitation program (r=0.569, P<0.001).

Conclusions

Cardiac rehabilitation protects against the expansion of small AAAs and mitigates the risk associated with AAA repair, possibly because of the decreased elevation of blood pressure during exercise.

Clinical Trial Registration

URL: upload.umin.ac.jp. Unique identifier: UMIN000028237.

Mild aerobic exercise blocks elastin fiber fragmentation and aortic dilatation in a mouse model of Marfan syndrome associated aortic aneurysm

Regular low-impact physical activity is generally allowed in patients with Marfan syndrome, a connective tissue disorder caused by heterozygous mutations in the fibrillin-1 gene. However, being above average in height encourages young adults with this syndrome to engage in high-intensity contact sports, which unfortunately increases the risk for aortic aneurysm and rupture, the leading cause of death in Marfan syndrome. In this study, we investigated the effects of voluntary (cage-wheel) or forced (treadmill) aerobic exercise at different intensities on aortic function and structure in a mouse model of Marfan syndrome. Four-week-old Marfan and wild-type mice were subjected to voluntary and forced exercise regimens or sedentary lifestyle for 5 mo. Thoracic aortic tissue was isolated and subjected to structural and functional studies. Our data showed that exercise improved aortic wall structure and function in Marfan mice and that the beneficial effect was biphasic, with an optimum at low intensity exercise (55-65% V̇o_2max) and tapering off at a higher intensity of exercise (85% V̇o_2max). The mechanism underlying the reduced elastin fragmentation in Marfan mice involved reduction of the expression of matrix metalloproteinases 2 and 9 within the aortic wall. These findings present the first evidence of potential beneficial effects of mild exercise on the structural integrity of the aortic wall in Marfan syndrome associated aneurysm. Our finding that moderate, but not strenuous, exercise protects aortic structure and function in a mouse model of Marfan syndrome could have important implications for the medical care of young Marfan patients.NEW & NOTEWORTHY The present study provides conclusive scientific evidence that daily exercise can improve aortic health in a mouse model of Marfan syndrome associated aortic aneurysm, and it establishes the threshold for the exercise intensity beyond which exercise may not be as protective. These findings establish a platform for a new focus on promoting regular exercise in Marfan patients at an optimum intensity and create a paradigm shift in clinical care of Marfan patients suffering from aortic aneurysm complications.

Effect of exercise training on C reactive protein: a systematic review and meta-analysis of randomised and non-randomised controlled trials

PURPOSE

C-reactive protein (CRP) is a marker of chronic systemic inflammation frequently used in cardiovascular disease risk assessment. The purpose of this meta-analysis was to provide a quantitative estimate of the magnitude of change in CRP following participation in physical exercise interventions.

METHODS

All studies included in the meta-analysis were peer reviewed and published in English. Human participants were assigned to a non-exercise comparison group or exercise training group, with the intervention lasting ≥2 weeks. CRP levels were measured at baseline, during and/or after completion of the exercise training programme. Random-effects models were used to aggregate a mean effect size (ES), 95% CIs and potential moderators.

RESULTS

83 randomised and non-randomised controlled trials met the inclusion criteria and resulted in 143 effects (n=3769). The mean ES of 0.26 (95% CI 0.18 to 0.34, p<0.001) indicated a decrease in CRP following exercise training. A decrease in body mass index (BMI; β=1.20, SE=0.25, p<0.0001) and %Fat (β=0.76, SE=0.21, p=0.0002) were associated with a decrease in CRP, independently accounting for 11.1% and 6.6% of the variation in response, respectively. Exercise training led to a greater reduction in CRP when accompanied by a decrease in BMI (ES=0.38, 95% CI 0.26 to 0.50); however, a significant improvement in CRP occurred in the absence of weight loss (ES=0.19, 95% CI 0.10 to 0.28; both p<0.001).

CONCLUSIONS

These results suggest that engaging in exercise training is associated with a decrease in CRP levels regardless of the age or sex of the individual; however, greater improvements in CRP level occur with a decrease in BMI or %Fat.

Patient recruitment and experiences in a randomised trial of supervised exercise training for individuals with abdominal aortic aneurysm

We sought to describe patient recruitment and experiences in a randomised controlled trial of a 12-week (thrice weekly) supervised exercise program for patients with small abdominal aortic aneurysm (AAA). Potential patients were identified via AAA surveillance lists and vascular clinics and invited to participate in the study. Upon completion of baseline assessments, patients were randomly allocated 1:1 to exercise or usual care. Patients completing the exercise arm were invited to attend a focus group session to explore experiences of diagnosis, management of condition, trial recruitment, and expectations and experiences of the exercise program. Between January 2010 and September 2011, 545 patients were identified. The response rate to postal invitation was 81.7% (445/545), with 108 patients responding as "interested." Only 28 of these patients were eligible and recruited (46.7% of recruitment target), yielding an overall recruitment rate of 5.1%. However, the estimated recruitment rate among eligible patients was 23.7%. Twenty-five patients (89.3%) completed the study, and compliance to the exercise program was 94%. Participants attending the focus group session indicated that the exercise program was manageable, beneficial, and enjoyable. The feasibility of supervised exercise training in individuals with small AAA remains unclear. Our study revealed a poorer than expected recruitment rate, but good compliance to, and feedback for, the exercise intervention. We present potential explanations for these findings and suggestions for future trials involving similar populations.

Surgery for small asymptomatic abdominal aortic aneurysms

BACKGROUND

An abdominal aortic aneurysm (AAA) is an abnormal ballooning of the major abdominal artery. Some AAAs present as emergencies and require surgery; others remain asymptomatic. Treatment of asymptomatic AAAs depends on many factors, but an important one is the size of the aneurysm, as risk of rupture increases with aneurysm size. Large asymptomatic AAAs (greater than 5.5 cm in diameter) are usually repaired surgically; very small AAAs (less than 4.0 cm diameter) are monitored with ultrasonography. Debate continues over the appropriate roles of immediate repair and surveillance with repair on subsequent enlargement in people presenting with asymptomatic AAAs of 4.0 cm to 5.5 cm diameter. This is the third update of the review first published in 1999.

OBJECTIVES

To compare mortality, quality of life, and cost effectiveness of immediate surgical repair versus routine ultrasound surveillance in people with asymptomatic AAAs between 4.0 cm and 5.5 cm in diameter.

SEARCH METHODS

For this update, the Cochrane Peripheral Vascular Diseases Group Trials Search Co-ordinator searched the Specialised Register (February 2014) and the Cochrane Central Register of Controlled Trials (CENTRAL; 2014, Issue 1). We checked reference lists of relevant articles for additional studies.

SELECTION CRITERIA

Randomised controlled trials in which men and women with asymptomatic AAAs of diameter 4.0 cm to 5.5 cm were randomly allocated to immediate repair or imaging-based surveillance at least every six months. Outcomes had to include mortality or survival.

DATA COLLECTION AND ANALYSIS

Three members of the review team independently extracted the data, which were cross-checked by other team members. Risk ratios (RR) (endovascular aneurysm repair only), hazard ratios (HR) (open repair only), and 95% confidence intervals based on Mantel-Haenszel Chi(2) statistic were estimated at one and six years (open repair only) following randomisation. We included all relevant published studies in this review.

MAIN RESULTS

For this update, four trials with a combined total of 3314 participants fulfilled the inclusion criteria. Two trials compared surveillance with immediate open repair; two trials compared surveillance with immediate endovascular repair. Overall, the risk of bias within the included studies was low and the quality of the evidence high. The four trials showed an early survival benefit in the surveillance group (due to 30-day operative mortality with surgery) but no significant differences in long-term survival (adjusted HR 0.88, 95% confidence interval (CI) 0.75 to 1.02, mean follow-up 10 years; HR 1.21, 95% CI 0.95 to 1.54, mean follow-up 4.9 years; HR 0.76, 95% CI 0.30 to 1.93, median follow-up 32.4 months; HR 1.01, 95% CI 0.49 to 2.07, mean follow-up 20 months). A pooled analysis of participant-level data from two trials (with a maximum follow-up of seven to eight years) showed no statistically significant difference in survival between immediate open repair and surveillance (propensity score-adjusted HR 0.99; 95% CI 0.83 to 1.18), and that this lack of treatment effect did not vary by AAA diameter (P = 0.39) or participant age (P = 0.61). The meta-analysis of mortality at one year for the endovascular trials likewise showed no significant association (RR at one year 1.15, 95% CI 0.60 to 2.17). Quality-of-life results among trials were conflicting.

AUTHORS' CONCLUSIONS

The results from the four trials to date demonstrate no advantage to immediate repair for small AAA (4.0 cm to 5.5 cm), regardless of whether open or endovascular repair is used and, at least for open repair, regardless of patient age and AAA diameter. Thus, neither immediate open nor immediate endovascular repair of small AAAs is supported by currently available evidence.

Exercise-induced changes in inflammatory processes: Implications for thrombogenesis in cardiovascular disease

Sedentary lifestyle is a risk factor and a strong predictor for chronic disease and premature death. Low-grade inflammation has been proved a key player in the pathogenesis of cardiovascular disease. Inflammatory processes have been also involved in maintaining the balance between coagulation and fibrinolysis. In addition, an inverse linear dose-response relation between physical activity and mortality risks has also been reported. However, the favorable effects of structured exercise programs and the independent contribution of physical activity to cardiovascular risk are still under investigation. In response to heavy exercise, interleukin-6 (IL-6) is secreted by contracting skeletal muscles, followed by an acute reactant release of C-reactive protein (CRP). Both CRP and IL-6 can stimulate monocyte tissue factor production, provoke platelet hyperreactivity, promote fibrinogen biosynthesis, and enhance microparticle formation and erythrocyte aggregability, thus triggering prothrombotic state. By contrast, regular exercise and physical activity are protective against all-cause mortality through suppressing pro-inflammatory cytokine production, enhancing anti-inflammatory mediators and antioxidant development, and promoting fibrinolytic activity. Low-load resistance exercise also plays an advantageous role in thrombogenesis by reducing inflammatory processes and potentiating fibrinolytic features. In the present review article, we provide an overview of the impact of different modes and intensities of physical activity on vascular inflammation and thrombogenesis.

Visceral adiposity is not associated with abdominal aortic aneurysm presence and growth

Previous studies in rodent models and patients suggest that visceral adipose could play a direct role in the development and progression of abdominal aortic aneurysm (AAA). This study aimed to assess the association of visceral adiposity with AAA presence and growth. This study was a case-control investigation of patients that did (n=196) and did not (n=181) have an AAA who presented to The Townsville Hospital vascular clinic between 2003 and 2012. Cases were patients with AAA (infra-renal aortic diameter >30 mm) and controls were patients with intermittent claudication but no AAA (infra-renal aortic diameter <30 mm). All patients underwent computed tomography angiography (CTA). The visceral to total abdominal adipose volume ratio was estimated from CTAs by assessing total and visceral adipose deposits using an imaging software program. Measurements were assessed for reproducibility by repeat assessments on 15 patients. AAA risk factors were recorded at entry. Forty-five cases underwent two CTAs more than 6 months apart to assess AAA expansion. The association of visceral adiposity with AAA presence and growth was examined using logistic regression. Visceral adipose assessment by CTA was highly reproducible (mean coefficient of variation 1.0%). AAA was positively associated with older age and negatively associated with diabetes. The visceral to total abdominal adipose volume ratio was not significantly associated with AAA after adjustment for other risk factors. Patients with a visceral to total abdominal adipose volume ratio in quartile four had a 1.63-fold increased risk of AAA but with wide confidence intervals (95% CI 0.71-3.70; p=0.248). Visceral adiposity was not associated with AAA growth. In conclusion, this study suggests that visceral adiposity is not specifically associated with AAA presence or growth although larger studies are required to confirm these findings.

High-intensity interval exercise training before abdominal aortic aneurysm repair (HIT-AAA): protocol for a randomised controlled feasibility trial

INTRODUCTION

In patients with large abdominal aortic aneurysm (AAA), open surgical or endovascular aneurysm repair procedures are often used to minimise the risk of aneurysm-related rupture and death; however, aneurysm repair itself carries a high risk. Low cardiopulmonary fitness is associated with an increased risk of early post-operative complications and death following elective AAA repair. Therefore, fitness should be enhanced before aneurysm repair. High-intensity interval exercise training (HIT) is a potent, time-efficient strategy for enhancing cardiopulmonary fitness. Here, we describe a feasibility study for a definitive trial of a pre-operative HIT intervention to improve post-operative outcomes in patients undergoing elective AAA repair.

METHODS AND ANALYSIS

A minimum of 50 patients awaiting elective repair of a 5.5-7.0 cm infrarenal AAA will be allocated by minimisation to HIT or usual care control in a 1:1 ratio. The patients allocated to HIT will complete three hospital-based exercise sessions per week, for 4 weeks. Each session will include 2 or 4 min of high-intensity stationary cycling followed by the same duration of easy cycling or passive recovery, repeated until a total of 16 min of high-intensity exercise is accumulated. Outcomes to be assessed before randomisation and 24-48 h before aneurysm repair include cardiopulmonary fitness, maximum AAA diameter and health-related quality of life. In the post-operative period, we will record destination (ward or critical care unit), organ-specific morbidity, mortality and the durations of critical care and hospital stay. Twelve weeks after the discharge, participants will be interviewed to reassess quality of life and determine post-discharge healthcare utilisation. The costs associated with the exercise intervention and healthcare utilisation will be calculated.

ETHICS AND DISSEMINATION

Ethics approval was secured through Sunderland Research Ethics Committee. The findings of the trial will be disseminated through peer-reviewed journals, and national and international presentations.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN09433624.

The association of visceral adiposity with cardiovascular events in patients with peripheral artery disease

BACKGROUND

Previous studies have suggested that patients with peripheral artery disease (PAD) suffer from a high incidence of cardiovascular events (CVE). Visceral adiposity has been implicated in promoting CVEs. This study aimed to assess the association of relative visceral adipose volume with incident cardiovascular events in patients with peripheral artery disease.

METHODS

This was a prospective cohort study including 260 patients with PAD who presented between 2003 and 2012. Cases were patients with diagnosed PAD including symptomatic lower limb athero-thrombosis and asymptomatic abdominal aortic aneurysm. All patients underwent computed tomography angiography (CTA). Abdominal visceral to total adipose volume ratio (relative visceral adipose volume) was estimated from CTAs using a previously validated workstation protocol. Cardiovascular risk factors were recorded at entry. The association of visceral adiposity with major CVEs (death, non-fatal myocardial infarction or stroke) was examined using Kaplan Meier and Cox proportional hazard analyses.

RESULTS

A total of 92 major CVEs were recorded in 76 patients during a median follow-up of 2.8 (IQR 1.2 to 4.8) years, including myocardial infarction (n = 26), stroke (n = 10) and death (n = 56). At 3 years the incidence of major CVEs stratified by relative visceral adipose volume quartiles were 15% [Quartile (Q) 1], 17% (Q2), 11% (Q3) and 15% (Q4) (P = 0.517). Relative visceral adipose volume was not associated with major CVEs after adjustment for other risk factors.

CONCLUSION

This study suggests that visceral adiposity does not play a central role in the predisposition for major CVEs in patients with PAD.

Medical treatment for small abdominal aortic aneurysms

BACKGROUND

Screening for abdominal aortic aneurysm (AAA) in selected groups is now performed in England, the USA and Sweden. Patients with aneurysms over 55 mm in diameter are generally considered for elective surgical repair. Patients with aneurysm diameters below or equal to 55 mm (termed 'small AAAs') are managed with aneurysm surveillance as there is currently insufficient evidence to recommend surgery in these cases. As more patients are screened, there will be an increasing number of small AAAs identified. There is interest in pharmaceutical interventions (for example angiotensin converting enzyme (ACE) inhibitors, antibiotics, beta-blockers, statins) which could be given to such patients to delay or reverse aneurysm expansion and reduce the need for elective surgical repair.

OBJECTIVES

To assess the effects of medical treatment on the expansion rate of small abdominal aortic aneurysms.

SEARCH METHODS

The Cochrane Peripheral Vascular Diseases Group Trials Search Co-ordinator searched the Specialised Register (May 2012) and CENTRAL (2012, Issue 5). Clinical trials databases were searched for details of ongoing or unpublished studies. The reference lists of articles retrieved by electronic searches were searched for additional citations.

SELECTION CRITERIA

We selected randomised trials in which patients with small AAAs allocated to medical treatment with the intention of retarding aneurysm expansion were compared to patients allocated to a placebo treatment, alternative medical treatment, a different regimen of the same drug or imaging surveillance alone.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted the data and assessed the risk of bias in the trials. Meta-analyses were used when heterogeneity was considered low. The two primary outcomes were the mean difference (MD) in aneurysm diameter and the odds ratio (OR) calculated to compare the number of individuals referred to AAA surgery in each group over the trial period.

MAIN RESULTS

Seven trials involving 1558 participants were included in this review; 457 were involved in four trials of antibiotic medication, and 1101 were involved in three trials of beta-blocker medication. Five of the studies were rated at a high risk of bias.Individually, all of the included trials reported non-significant differences in AAA expansion rates between their intervention and control groups.The two major drug groups were then analysed separately. For AAA expansion it was only possible to combine two of the antibiotic trials in a meta-analysis. This demonstrated that roxithromycin had a small but significant protective effect (MD -0.86 mm; 95% confidence interval (CI) -1.57 to -0.14). When referral to AAA surgery was compared (including all four antibiotic trials in the meta-analysis), non-significantly fewer patients were referred in the intervention groups (OR 0.96; 95% CI 0.59 to 1.57) than the control groups. When only the trials reporting actual elective surgery were included in a subgroup analysis, the result remained statistically non-significant (OR 1.17; 95% CI 0.57 to 2.42).For the beta-blocker trials, when all were combined in a meta-analysis, there was a very small, non-significant protective effect for propranolol on AAA expansion (MD -0.08 mm; 95% CI -0.25 to 0.10), and non-significantly fewer patients were referred to AAA surgery in the propranolol group (OR 0.74; 95% CI 0.52 to 1.05). Bronchospasm and shortness of breath were the main adverse effects from the beta-blockers. In one trial the adverse effects were reportedly so severe that the trial was stopped early after two years.

AUTHORS' CONCLUSIONS

There is some limited evidence that antibiotic medication may have a slight protective effect in retarding the expansion rates of small AAAs. The quality of the evidence makes it unclear whether this translates into fewer referrals to AAA surgery, owing mainly to the small sample sizes of the studies.Antibiotics were generally well tolerated with minimal adverse effects. Propranolol was poorly tolerated by patients in all of the beta-blocker trials and demonstrated only minimal and non-significant protective effects. Further research on beta-blockers for AAA needs to consider the use of drugs other than propranolol.In general, there is surprisingly little high quality evidence on medical treatment for small AAAs, especially in relation to the use of newer beta-blockers, ACE inhibitors and statins.

Endurance exercise training in patients with small abdominal aortic aneurysm: a randomized controlled pilot study

OBJECTIVE

To investigate the feasibility of endurance exercise training in patients with small abdominal aortic aneurysm (AAA), and to obtain preliminary data of its impact on important health outcomes.

DESIGN

Randomized controlled pilot study.

SETTING

University rehabilitation facility.

PARTICIPANTS

Patients with small AAA (N=28; mean age ± SD, 72±7 y).

INTERVENTION

Participants were randomized to a 12-week program of moderate-intensity endurance exercise or standard care control (encouragement to exercise only).

MAIN OUTCOME MEASURES

Safety was assessed in terms of the frequency of adverse events and changes in maximum AAA diameter. Outcomes were assessed at baseline and 12 weeks including cardiopulmonary fitness (ventilatory threshold), health-related quality of life (Medical Outcomes Study 36-Item Short-Form Health Survey [version 2]), and markers of vascular risk (eg, blood pressure and high-sensitivity C-reactive protein).

RESULTS

Of 545 patients contacted, 28 (5%) entered the trial. There were 3 (11%) dropouts. Adherence to the exercise program was 94%. There were no paradoxical increases in AAA size or adverse clinical events. Ventilatory threshold increased in the exercise group, but not the control group (adjusted mean difference, 2.5 mL·kg(-1)·min(-1); 95% confidence interval, 0.5-4.5; d=.82). Systolic blood pressure and high-sensitivity C-reactive protein decreased in the exercise group compared with the control group (d=.34 and d=.58, respectively). There were no substantial changes in anthropometric variables or quality of life.

CONCLUSIONS

Despite a low recruitment rate, the findings suggest that moderate-intensity endurance exercise training is feasible in patients with small AAA, and can evoke improvements in important health outcomes.

Perioperative exercise training in elderly subjects

The association between physical fitness and outcome following major surgery is well described - less fit patients having a higher incidence of perioperative morbidity and mortality. This has led to the idea of physical training (exercise training) as a perioperative intervention with the aim of improving postoperative outcome. Studies have started to explore both preoperative training (prehabilitation) and postoperative training (rehabilitation). We have reviewed the current literature regarding the use of prehabilitation and rehabilitation in relation to major surgery in elderly patients. We have focussed particularly on randomised controlled trials, systematic reviews and meta-analyses. There is currently a paucity of high-quality clinical trials in this area, and the evidence base in elderly patients is particularly limited. The review indicated that prehabilitation can improve objectively measured fitness in the short time available prior to major surgery. Furthermore, for several general surgical procedures, prehabilitation using inspiratory muscle training may reduce the risk of some specific complications (e.g., pulmonary complications and predominately atelectasis), but it is unclear whether this translates into an improvement in overall surgical outcome. There is clear evidence that rehabilitation is of benefit to patients following cancer diagnoses, in terms of physical activity, fatigue and health-related quality of life. However, it is uncertain whether this improved physical function translates into increased survival and delayed disease recurrence. Prehabilitation using continuous or interval training has been shown to improve fitness but the impact on surgical outcomes remains ill defined. Taken together, these findings are encouraging and support the notion that pre- and postoperative exercise training may be of benefit to patients. There is an urgent need for adequately powered randomised control studies addressing appropriate clinical outcomes in this field.

Hemodynamic changes quantified in abdominal aortic aneurysms with increasing exercise intensity using mr exercise imaging and image-based computational fluid dynamics

Abdominal aortic aneurysm (AAA) is a vascular disease resulting in a permanent, localized enlargement of the abdominal aorta. We previously hypothesized that the progression of AAA may be slowed by altering the hemodynamics in the abdominal aorta through exercise [Dalman, R. L., M. M. Tedesco, J. Myers, and C. A. Taylor. Ann. N.Y. Acad. Sci. 1085:92-109, 2006]. To quantify the effect of exercise intensity on hemodynamic conditions in 10 AAA subjects at rest and during mild and moderate intensities of lower-limb exercise (defined as 33 ± 10% and 63 ± 18% increase above resting heart rate, respectively), we used magnetic resonance imaging and computational fluid dynamics techniques. Subject-specific models were constructed from magnetic resonance angiography data and physiologic boundary conditions were derived from measurements made during dynamic exercise. We measured the abdominal aortic blood flow at rest and during exercise, and quantified mean wall shear stress (MWSS), oscillatory shear index (OSI), and particle residence time (PRT). We observed that an increase in the level of activity correlated with an increase of MWSS and a decrease of OSI at three locations in the abdominal aorta, and these changes were most significant below the renal arteries. As the level of activity increased, PRT in the aneurysm was significantly decreased: 50% of particles were cleared out of AAAs within 1.36 ± 0.43, 0.34 ± 0.10, and 0.22 ± 0.06 s at rest, mild exercise, and moderate exercise levels, respectively. Most of the reduction of PRT occurred from rest to the mild exercise level, suggesting that mild exercise may be sufficient to reduce flow stasis in AAAs.

Current status of medical management for abdominal aortic aneurysm

Previous trials indicate that surgical management of small abdominal aortic aneurysms (AAA) does not reduce mortality. The medical management of AAA, however, has to a large degree been ignored until recently. Medical management is not only needed to limit the expansion of small AAAs but also to reduce the high incidence of other cardiovascular events in these patients. In this review current evidence regarding medical therapy for patients with small AAAs is discussed. Four current randomised controlled trials are examining the efficacy of exercise, doxycycline and angiotensin converting enzyme inhibition in limiting AAA progression. A further trial using a mast cell stabilisation agent is expected to start soon. It is anticipated that a range of novel therapies for small AAAs will be identified within the next decade.