Abstract
Summary: In patients with peripheral arterial disease (PAD), the ability to perform physical exercise is an essential and most important indicator of a patient’s health and quality of life. In many cases, there exists a discrepancy between lower extremity blood flow, the extent of arterial occlusion shown by morphological investigation and functional impairment. Reversal of lower extremity arterial obstruction with revascularization does not always reverse functional impairment of diseased leg. Further, training exercise and drug treatment can improve functional performance although they are not associated with an improvement in arterial obstruction. Therefore, the determination of functional impairment and its recovery after different therapeutic procedures should be determined using objective tests. The most frequently used functional tests are treadmill exercise testing and a 6-minute walk test. The constant load test, in which results are expressed as a walked distance, does not always permit an accurate assessment of the full range of functional impairment of PAD patients. Recently, as a substitute for a constant-load test, the graded treadmill test is used. With this test, it is possible to identify those individuals with exercise limitations who are not caused only by deterioration of the blood flow of lower limbs. The 6-minute walk test is simple to perform and requires minimal equipment. However, the correlation between the 6-minute walk test and the graded treadmill test is relatively weak, indicating that peak performance on a graded treadmill may reflect different pathophysiological mechanisms of limitations. In conclusion: for the determination of limitations of mobility and quality of life in patients with PAD, objective measures of functional impairment are needed. The determination of functional capacity is related to the quality of life and is a useful tool for investigation of the success of revascularization of peripheral arteries and conservative treatment.
References
1 . Mortality rates at 10 years are higher in diabetic than in non-diabetic patients with chronic lower extremity peripheral arterial disease. Vasc Med. 2016;21(5):445–52.
2 The fate of patients with intermittent claudication in the 21st century revisited – results from the CAVASIC Study. Sci Rep. 2017;8:45833.
3 . A randomized, controlled trial of a geriatric assessment unit in a community rehabilitation hospital. N Engl J Med. 1990;322(22):1572–8.
4 Leg symptoms in peripheral arterial disease: associated clinical characteristics and functional impairment. JAMA. 2001;286(13):1599–606.
5 . Exertional leg symptoms other than intermittent claudication are common in peripheral arterial disease. Arch Intern Med. 1999;159(4):387–92.
6 . Measurement of walking endurance and walking velocity with questionnaire: validation of the walking impairment questionnaire in men and women with peripheral arterial disease. J Vasc Surg. 1998;28(6):1072–81.
7 . The evaluation of exercise performance in patients with peripheral vascular disease. Journal of Cardiopulmonary Rehabilitation and Prevention. 1988;8(12):525–32.
8 The ankle brachial index is associated with leg function and physical activity: the Walking and Leg Circulation Study. Ann Intern Med. 2002;136(12):873–83.
9 Association between physical activity and walking capacity with cognitive function in peripheral artery disease patients. Eur J Vasc Endovasc Surg. 2018;55(5):672–8.
10 . Coupling of external to cellular respiration during exercise: the wisdom of the body revisited. Am J Physiol. 1994;266(4 Pt 1):E519–39.
11 . The treadmill is a better functional test than the 6-minute walk test in therapeutic trials of patients with peripheral artery disease. Circulation. 2014;130(1):69–78.
12 . Physiology in medicine: peripheral arterial disease. J Appl Physiol (1985). 2013;115(9):1219–26.
13 . Inflammation in peripheral artery disease. Circulation. 2010;122(18):1862–75.
14 . Decreased NADH dehydrogenase and ubiquinol-cytochrome c oxidoreductase in peripheral arterial disease. Am J Physiol Heart Circ Physiol. 2001;280(2):H603–9.
15 . The association of acute exercise-induced ischaemia with systemic vasodilator function in patients with peripheral arterial disease. Vasc Med. 2008;13(4):255–62.
16 . Functional benefits of peripheral vascular bypass surgery for patients with intermittent claudication. Angiology. 1993;44(1):1–10.
17 . Natural history of physical function in older men with intermittent claudication. J Vasc Surg. 2004;40(1):73–8.
18 . Exercise for intermittent claudication. Cochrane Database Syst Rev. 2014(7):CD000990.
19 . Progressive vs single-stage treadmill tests for evaluation of claudication. Med Sci Sports Exerc. 1991;23(4):402–8.
20 . Reproducibility of constant-load treadmill testing with various treadmill protocols and predictability of treadmill test results in patients with intermittent claudication. J Vasc Surg. 2002;36(1):83–8.
21 Pentoxifylline efficacy in the treatment of intermittent claudication: multicenter controlled double-blind trial with objective assessment of chronic occlusive arterial disease patients. Am Heart J. 1982;104(1):66–72.
22 . Maximal oxygen intake and nomographic assessment of functional aerobic impairment in cardiovascular disease. Am Heart J. 1973;85(4):546–62.
23 . Superiority of treadmill walking exercise versus strength training for patients with peripheral arterial disease. Implications for the mechanism of the training response. Circulation. 1994;90(4):1866–74.
24 Supervised exercise versus primary stenting for claudication resulting from aortoiliac peripheral artery disease: six-month outcomes from the claudication: exercise versus endoluminal revascularization (CLEVER) study. Circulation. 2012;125(1):130–9.
25 . Evaluation of walking impairment by questionnaire in patients with peripheral arterial disease. J Vasc Med Biol. 1990;2:142–52.
26 Correlation of patient-reported symptom outcomes and treadmill test outcomes after treatment for aortoiliac claudication. J Vasc Interv Radiol. 2013;24(10):1427–35; quiz 36.
27 . Association between lower-extremity function and arterial compliance in older adults. Angiology. 2008;59(2):203–8.
28 . The clinical utility of a six-minute walk test in peripheral arterial occlusive disease patients. J Am Geriatr Soc. 1998;46(6):706–11.
29 . Corridor-based functional performance measures correlate better with physical activity during daily life than treadmill measures in persons with peripheral arterial disease. J Vasc Surg. 2008;48(5):1231–7, 7.e1.
30 Exercise rehabilitation improves functional outcomes and peripheral circulation in patients with intermittent claudication: a randomized controlled trial. J Am Geriatr Soc. 2001;49(6):755–62.
31 Functional decline in peripheral arterial disease: associations with the ankle brachial index and leg symptoms. JAMA. 2004;292(4):453–61.
32 . Six-minute walk is a better outcome measure than treadmill walking tests in therapeutic trials of patients with peripheral artery disease. Circulation. 2014;130(1):61–8.
33 Baseline functional performance predicts the rate of mobility loss in persons with peripheral arterial disease. J Am Coll Cardiol. 2007;50(10):974–82.
34 . Exercise performance in patients with peripheral arterial disease who have different types of exertional leg pain. J Vasc Surg. 2007;46(1):79–86.
35 . The diagnosis of ischaemic heart pain and intermittent claudication in field surveys. Bull World Health Organ. 1962;27:645–58.
36 . The Edinburgh Claudication Questionnaire: an improved version of the WHO/Rose Questionnaire for use in epidemiological surveys. J Clin Epidemiol. 1992;45(10):1101–9.
37 . Methods of symptom evaluation and their impact on peripheral artery disease (PAD) symptom prevalence: a review. Vasc Med. 2013;18(2):95–111.
38 . The usefulness of transcutaneous oximetry in assessing the success of percutaneous transluminal angioplasty. Eur J Vasc Endovasc Surg. 2002;24(6):528–32.
39 . A phase II dose-ranging study of the phosphodiesterase inhibitor K-134 in patients with peripheral artery disease and claudication. J Vasc Surg. 2012;55(2):381–9.e1.
40 . A systematic review and meta-analysis of propionyl-L-carnitine effects on exercise performance in patients with claudication. Vasc Med. 2013;18(1):3–12.