The Unusual Improvement of Intermittent Claudication Distance in Patient with Peripheral Arterial Disease Utilizing “2/3 Claudication Distance” Protocol of Exercise Training

Peripheral arterial disease (PAD) affects 12% - 20% of the population over 65 years. PAD is a component of systemic atherosclerosis and is associated with increased rate of all-cause mortality and cardiovascular events, compared with those without PAD. The strongest risk factors for PAD are older age and cigarette smoking. PAD accelerates functional decline leading to physical disability. Many randomized clinical trials demonstrated that treadmill walking training increases pain-free and maximal walking distances in patients with PAD. Exercise intervention is strongly recommended for patients with PAD and symptoms of intermittent claudication (IC). The need to provide an exercise training program to patients with peripheral arterial disease is essen-tial, as almost half of these patients will eventually develop coronary artery disease. There are many existing treadmill walking protocols for patients with PAD. Most of these are based on claudication severity. We present a case of significant improvement of pain-free distance and maximum treadmill walking distance in a patient with PAD after 12 weeks of walking training program utilizing the “2/3 claudication distance” formula. The Unusual Improvement of Intermittent Claudication Distance in Patient with Peripheral Arterial Disease Utilizing “2/3 Claudication Distance” Protocol of Exercise Training. Case Reports in

comprehensive and coordinated use of medical, social, educational and professional resources to accommodate patients to a new lifestyle and enable them to achieve the best performance" [1]. The cardiac rehabilitation program consists of physical exercise sessions, dietary counselling, educational classes on lifestyle changes and psychosocial support to patients and their families. Supervised exercise training remains a core component of the cardiac rehabilitation program, focusing on aerobic, resistance, neuromotor and flexibility components. Cardiac rehabilitation is recommended for patients with PAD and claudication, as it reduces symptoms, prolongs claudication distance and improves quality of life [2].
The goals of a comprehensive cardiac rehabilitation program in cases of patients with PAD include symptoms reduction, improvement of exercise capacity and a decrease in the risk of cardiovascular events. Cardiac rehabilitation program outcome measures include exercise capacity, modifiable risk factors (blood lipid and glucose levels, blood pressure, smoking), psychological outcomes (depression, anxiety), return to work and quality of life. All of them can be easily quantified and interpreted. Functional capacity assessment includes maximum work-load from exercise test (as peak oxygen uptake in ml/kg/min or as a value in metabolic equivalents) or change in distance achieved on a 6-minute walking.
A meta-analysis of 21 studies performed in 1995 concluded that a supervised exercise improved maximum walking distance on a treadmill by 122% and pain-free walking distance on a treadmill by 179% [3]. Benefits of exercise training exist also among patients with PAD who do not have claudication. The disputable question remains as to which walking treadmill protocols are optimal and most effective for patients with PAD.

Case Report
A 59-year-old male patient, active smoker (half a pack a day for 20 years), with peripheral arterial disease and 100 meters claudication distance has been admit- Full training consists of three such cycles with 10 minutes break between each.
Ideally the patient should perform such training three times a day, most days of the week. Such a program should be continued for at least 3 -4 months. In cases where pain occurs, rest periods should be taken until pain subsides and subsequent walking blocks should be adjusted accordingly. In this case the patient repeated such training two times more during exercise days and three times during non-exercise days in addition to his supervised sessions. After 12 weeks of training, the distances attained prior to the onset of pain and to unbearable pain significantly increased to 420 and 585 meters respectively. Controlled ABI increased by 0.1 at the right and left dorsalis pedis respectively and controlled graded stress test had been terminated due to leg pain after reaching 6.5 MET.

Discussion
Exercise intervention is strongly recommended for patients who present with peripheral artery disease. Regular exercise sessions reduce symptoms, prolong claudication distance and improve quality of life in patients with PAD. It must be remembered that patients with PAD and claudication have about 50% reduction in peak oxygen consumption in comparison with age-matched individuals [4]. It affects their functional status, but also their quality of life and they often start to avoid physical activity, especially walking, which in turn leads to further decline in functional status. Patients with PAD present also with higher prevalence of depression [5]. As mentioned earlier, meta-analysis from 1995 revealed increase of maximal walking distance by 122% and pain-free walking distance by 180% [6]. weeks [10]. In a trial trainings ranged in duration from 4 to 104 weeks (more than half had durations between 12 and 26 weeks). Whereas we strictly followed the model of 3 supervised sessions per week, lasting at least 30 minutes each, with a total program duration of 12 weeks, both training protocols and training progression at our center vary. We consistently commence with precise calculation of distances to onset of claudication and to unbearable pain. Based on these we start the exercise walking treadmill sessions utilizing one of existing protocols (eg. Dahloff, Larsen or "2/3 claudication distance" formula). In a case of "2/3 claudication distance" training protocol, we commence the first treadmill walk- patient reached over 300%, which is significant in comparison with data from the literature. What we found as a real advantage of 2/3 claudication formula is the absence of severe pain. Covering 2/3 claudication distance rarely provokes maximal pain. If present, usually a mild degree and well tolerated pain occurred which did not affect the overall training schedule. One of potential pitfalls of protocols till moderate to severe pain is low program adherence, related to pain intolerance. i.e. some patients reduce the number of training sessions or even avoid walking. Regular (i.e. once a week) recalculation of distance to onset of claudication and to maximal walking distance allows for adequate training progression by increasing duration of walking blocks, without workload change. In practice we used constant speed (3.0 or 3.5 km/h) with no grade, and increased training duration. From our experience "2/3 claudication distance" formula seems to be a feasible and very effective exercise intervention for patients with peripheral arterial disease and intermittent claudication.