- Email: [email protected]
risk modification program
Vascular rehabilitation: Benefits of a structured exercise/risk modification program Larry R. Williams, M D , Mitzi A. Ekers, R N , M S N , Paul Steven Collins, M D , and J o h n F. Lee, M D , St. Petersburg, Fla. A vascular rehabilitation program was designed to increase exercise tolerance and reduce the risk of cardiovascular disease in patients with lower extremity arterial occlusive disease. Sixty-eight patients (32 men, 36 women); ages 55 to 85 years (mean, 68 years) with claudication 30 (44%), or recovering from lower extremity revascularization 36 (53%), or endovascular procedures 2 (3%) entered the vascular rehabilitation program. Each underwent a physical examination, risk factor assessment, noninvasive arterial studies, and cardiac evaluation. A history was taken from each patient also. Six patients (9%) were excluded on recognition of silent myocardial ischemia. Sixty-two patients (91%) were accepted for exercise training in a program designed to offer 24 (1-hour) monitored exercise sessions, 12 (1-hour) personalized education lectures, and development of a home maintenance exercise program. No deaths or major morbidity occurred. Seventeen patients (27%) did not finish the program, eight (13%) because of development of significant cardiac, extremity, or cerebrovascular disease and nine for nonmedical reasons. Of the 45 patients (73%) who completed the program, 38 (88%) had documented increases in walking distances of greater than 100% (122% to 450%). All 45 patients designed home exercise programs, and 88% of the smokers quit. Long-term follow-up was available on 100% of the patients. Thirty-eight patients (84%) have been followed for 2 years or more. Thirty-eight (84%) maintained or improved walking distances recorded on exit from the program. Thirty of the 36 patients (83%) who stopped smoking remained nonsmokers. Significant reductions in cholesterol were seen at 1 year, and significant reductions in triglycerides were seen at 12 weeks and 1 year. The vascular rehabilitation program resulted in an immediate improvement in exercise tolerance, reduction of known cardiovascular risk factors, and behavior modification resulting in long-term compliance. In addition, prescreening and exercise supervision identified a significant number of patients at increased cardiovascular risk in whom independent exercise may have proved dangerous. (J VASe Suv,~ 1991;14:320-6.)
Structured programs for physical reconditioning and risk factor modification have proved beneficial in patients with atherosclerotic coronary disease. 1-7 However, similar programs for patients whose initial atherosclerotic complication is peripheral arterial insufficiency have not been widely developed. This has occurred in spite of the known benefit of exercise in increasing ambulation distances and the acceptance of exercise by most vascular surgeons as a valuable tool in the management of patients with claudicafion. 8-1° The purpose of this study was to
From Saint Anthony'sHospital, St. Petersburg. Presented at the Fifteenth Annual Meeting of the Southern Association for Vascular Surgery, Palm Springs, Calif., Jan. 23-26, 1991. Reprint requests: Larry R. Williams,MD, 735 Twelfth St. N., Saint Petersburg, FL 33705. 24/6/29894 320
initiate a vascular rehabilitation program (VRP) in a cohort of patients with atherosclerosis who had a variety of lower extremity symptoms. The VRP was designed to increase exercise tolerance and reduce the risk of progressive cardiovascular disease by decreasing atherogenic risk factors. PATIENTS AND METHODS From July 1986 to July 1988, 68 patients, 32 men and 36 women, ranging in age from 55 to 85 years (mean, 68 years) were enrolled in the VRP. Thirtysix patients (53%) were admitted to the program after lower extremity revascularization operations, and two patients (3%) had undergone laser-assisted balloon dilation. After operation all 38 patients mentioned in the previous sentence continued to have intermittent claudication. The remaining 30 patients (44%) were referred with intermittent clandication and had no operative intervention (Table I).
Volume 14 Number 3 September 1991
All patients with significant claudication ( < t w o blocks) were considered suitable candidates for the program. Patients were not preselected based on the severity of their initial disability. The VRP consisted of three phases (Table II). Phase I was initiated on referral of the patient's physician, who may or may not have been a vascular surgeon. Patients underwent a comprehensive evaluation that included recording of a history and performance of a physical examination, reporting of lower extremity-Doppler derived systolic pressures and calculation of ankle/brachial indexes, a lipid profile evaluation, and identification of risk factors for atherosclerotic disease. Those risk factors noted included a significant past history of atherosclerosis or coronary artery disease, smoking or other nicotine use, hypercholesterolemia, obesity, diabetes mellitus, and hypertension (Table I). Patients then underwent graded exercise testing by use of either a treadmill or bicycle ergometer with monitoring by a physician. This test was done to detect underlying cardiac disease and provided information required for calculating the individual exercise prescription. If significant underlying silent cardiac disease was discovered, the patient was referred for further cardiologic evaluation and not enrolled in the VRP. Once the patient successfully completed the graded exercise test, phase II commenced with preparation of an initial rehabilitative physical exercise prescription by use of guidelines established by the American College of Sports Medicine. 11 Resting heart rate, maximum heart rate, and metabolic equivalent of oxygen consumption determined from the graded exercise test were used to calculate net and training oxygen consumption and training metabolic equivalent of oxygen consumption. Entry levels for initiation of exercise training were set at 50% of functional capacity; exercise activities were selected for variety and to accommodate specific patient limitations according to known energy expenditures at the desired exercise levels.l~ Activities included use of the treadmill for walking, stationary bicycle, steps, arm crank, and rowing machine and free weights. These were set up as stations to be performed during each training session. At each station patients measured heart rate, time to onset of symptoms, maximum exercise time, and subjective "difficulty" using the 1 to 20 Rating of Perceived Exertion scale developed by Borg? 2 The exercise session, outlined in Table III, included check-in with resting heart rate, blood pressure, and weight; warmup; individual work stations; and cool-down periods. The 12-week program consisted of a minimum of 24 physical
Vascular rehabilitation 321
Table I. Admission diagnosis and risk factors Claudication (Nonoperated) Clandication (Postrevascularization) Aortofemoral Infrainguinal Dilation Risk factors Smoking Hypertension Diabetes mellitus Previous myocardial infarction Hypercholesterolemia Stroke Obesity
30 (44%) 38 (56%) 6 (9%) 3 0 (44%) 2 (3%) 56 (82%) 34 (50%) 18 (26%) 24 (24%) 16 (18%) 4 (6%) 4 (6%)
Table II. Vascular rehabilitation Phase I Referral by physician History and physical examination Risk factor profile Cholesterol/triglyceride analysis Segmental Doppler pressures Graded exercise testing (cardiac stress test) Phase II Initial rehabilitation exercise prescription 12-week program of exercise, education, monitoring Phase III Home maintenance program Periodic assessment and modification
reconditioning sessions (two 1-hour sessions per week). The patients .also underwent 12 (1-hour) personalized education lectures for reduction and control of athcrosclerotic risk factors. Specific topics addressed included hypercholesterolemia, diabetes mellitus, and overview of atherosclerosis, smoking reduction, and education regarding claudication and vascular operations as applicable. These lectures were supplemented with additional individual consultation with a registered dietician, respiratory therapist, exercise physiologist, nurse, or physician as necessary. Smoking cessation classes were maintained for ongoing support to initiate and maintain abstinence from tobacco. Plans were also developed at this time for a home maintenance exercise program. Guidelines for patient completion of the VKP were (1) improvement in exercise tolerance, (2) delayed onset and decreased severity of claudication to a level that had a minimal effect on walking ability, (3) understanding of safe exercise practices and guidelines for a home maintenance program, (4) development of a regular exercise regimen at home and a commitment to continue this practice, (5) attendance at all educational lectures and (6) correct
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Table III. Exercise session Minutes Check-in, resting pulse, blood pressure, weight, warm-up.routine Work stations ~ Cool-down, stretching Total body relaxation Total
10 35 10 5 60
~Recordings at each station: heart rate, time to development of first symptoms, maximum exercise time, rate of perceived exertion (Borg12).
identification of the signs, symptoms, and proper management of the risks of atherosclerosis. These guidelines were helpful in determining when patients could safely advance to their home maintenance program (phase III); however, they were not strictly interpreted as success or failure within the program. Patients were evaluated at entry level, 6 weeks, 12 weeks, and every 3 months on an ongoing basis. Walking distance measurements were recorded as time to development of first symptoms and maximum walking time. Percentage increases in walking time were determined, and Doppler-derived ankle/brachial systolic pressure indexes were calculated. Serum cholesterol and triglyceride determinations were made as milligrams per deciliter after a 12-hour overnight fast. Personal questionnaires were completed to ascertain adherence to diets, smoking cessation, and home exercise programs. Data were analyzed by use of a mixed analysis of variance (ANOVA) with gender as the between variable and time as the within variable. Schefe a posteriori analysis was used to determine significant differences at each time interval. Differences were considered significant at the L0.01 confidence level. The VRP was approved by the St. Anthony's Hospital Institutional Review Board. All patients were thoroughly informed and gave appropriate consent in writing before evaluation and entry into the program. RESULTS
Six (9%) of the 68 patients initially evaluated (phase I) for the program were found to have significant cardiac disease on the graded exercise test, in spite of the fact that patients with known symptomatic coronary occlusive disease were not accepted for evaluation. These six patients were referred back to their primary physician for consideration of further cardiologic consultation. The
remaining 62 patients entered phase II of the program (monitored exercise and risk factor modification). No deaths or major morbidity occurred. Seventeen patients (27%) did not complete the 12-week program. Nine of these patients left the program for nonmedicai reasons: four moved from the area, three stated only that they did not like the program or had scheduling conflicts, and two gave no reason. Eight patients (13%) left the program because of the development or recognition of significant cardiovascular problems. Four problems were cardiac related: exercise limiting angina developed in three patients midway through the program, and shormess of breath as a result of congestive heart failure developed in one patient. After consultation with their referring physicians, they were excluded from the program for further medical treatment. Difficulties with their extremities developed in two patients. One patient was actually unaware that her femoropopliteal bypass graft was acutely thrombosed until her exercise session reproduced her original daudication at a very short distance. After thrombectomy she was eventually readmitted to the program. Increasingly severe symptoms in the opposite leg developed in another patient, and she dropped out of the program for revascularization of that extremity. Transient ischemic attacks developed in two patients while they were in the program, and they were referred for further cerebrovascular evaluation (Table IV). Forty-five patients graduated from the 12-week phase II program. All 45 (100%) designed a home maintenance program for exercise and continued surveillance of their specific risk factor modifications (phase III), and all have had formal evaluations every 3 months. Nineteen patients (42%), however, found the organized program more stimulating and chose to continue in phase II for one or more (up to six) additional 12-week periods before advancing to their phase III program. Thirty-eight patients (84%) have been followed for at least 24 months, and 35 (92%) of these have maintained their regular phase III programs. All 35 have avoided any further extremity, cardiac, or cerebrovascular symptoms, and no one has required rehospitalization for cardiovascular related illness. Two patients moved from the area and lost interest, and one patient died of lung cancer. Walking distance All 45 patients who completed the phase II program had significant increases in walking distances measured both as the time to development of
Volume 14 Number 3 September 1991
Table IV. Patient progress 68 Patients initially considered 6 (9%) Significant cardiac disease at initial evaluation (phase I) 17 (27%) Started the program and dropped out during phase II 8 - Nonmedical reasons 3 - Angina 1 - Congestive failure 2 - Extremity ischemia 2 - Cerebrovascular symptoms 45 (66%) Graduates from phase II 45 (100%) Development of phase III programs
first calf or thigh pain and maximum walking distance (Table V). Symptom-ftee walking time increased an average of 107% at the completion of phase II. This improvement was maintained at the 1- and 2-year follow-up points with no significant continued improvement. Maximal walking time increased an average of 210% at the completion of phase II, however, it showed an additional significant increase at the 1-year point. No additional improvement was noted at 2 years. At long-term follow-up, walking distances recorded at exit were maintained or improved in 84% of the patients. Ankle/brachial index Although in some patients increased walking distances at the completion of phase II were accompanied by increases in the Doppler-derived ankle/brachial blood pressure indexes, this was not the rule. As depicted in Table VI, anlde/brachial indexes were not significantly different on average at the completion of phase II. At the 1-year follow-up significant increases were found in the mean ankle pressures. No difference was found between measurements at 1 and 2 years. Although a wide range (0.31 to 0.71) was found in the ankle/brachial indexes across the group, individual patient anlde/brachial indexes were relatively stable during the total evaluation time. Improved walking distances were noted regardless of whether the patients had undergone prior revascularization operations or had never been operated on. Serum lipid profile At the completion of phase II (12 weeks) significant reductions were seen in serum triglyceride levels (Table VII). Additional significant lowering was seen at 1-year follow-up, and this was maintained at the 2-year evaluation. Although many patients demonstrated reductions in cholesterol levels at the 12-week point, the results for the group were not
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Table V. Walking distances ~ % Increase
12 Weeks
Symptom-free walking Range 62%-320% Mean 107% Maximum walking Range 53%-450% Mean 210%
1 Year
2 Years
83%-411% 149%
91%-402% 178%
59%-600% 272%
61%-522% 257%
~Measured as treadmill walking times.
statistically significant. However, significant reductions in cholesterol were seen at the 1-year point, with no significant continued reduction at 2 years. Smoking The response to smoking cessation emphasis was gratifying; 36 of the 41 smokers (88%) stopped smoking. Long-term (2-year) abstinence from tobacco products was maintained in 30 of these patients (83%). DISCUSSION
Regular physical exercise is widely recommended and generally accepted as a valuable intervention in patients with a variety of symptoms caused by atherosclerosis. Many organized programs have been developed to aid patients in their recovery from myocardial infarction and coronary artery bypass surgery. 1-8 However, similar patients, often with identical risk factors and disease distribution, who are more limited by their lower extremity arterial insufficiency, are often given little or no assistance in modifying their life-styles to avoid future atherosclerotic complications. The VRP here outlined has successfully met this challenge. Exercise tolerance measured as both symptom-free and maximal walking times were significantly increased, with these benefits maintained over a 2-year follow-up. These results compare favorably with previously described exercise studies. Larsen and Lassen 13showed a 300% average increase in walking distance in patients in an organized walking class, as compared to a control group who exhibited no change. Ekroth et al?4 studied 148 patients with intermittent claudication in a 6-month training program. Walking ability increased in 88% of patients with an average increase of 234% in maximal walking distance. Rosetsky et al? s likewise showed significant improvements in walking distance with organized exercise instruction in patients with intermittent claudication. Lundgren et a1.16 recently reported the additive beneficial effect of lower
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Table VI. Doppler ankle/brachial indexes Range Mean
Baseline
12 Weeks
1 Year
2 Years
0.33-1.00 0.73
0.31-1.00 0.75
0.35-1.00 0.78*
0.35-1.00 0.78*
*p < 0.01. Table VII. Serum lipid profile Cholesterol (mg/dl) Range Mean Triglycerides (mg/dl) Range Mean
Baseline
12 Weeks
1 Year
2 Years
156-446 286
152-396 270
144-260 222*
151-251 210"
172-735 382
156-522 310"
143-400 262*
140-352 240*
*p < 0.01.
extremity revascularization and subsequent exercise training when compared with operation or exercise training alone. Although some have suggested that this increased exercise ability is due to increased peripheral blood flow and/or development of collateral circulation or increased numbers of capillaries, ~7-~9this view is not unanimous. 2°-22 In the study of Ekroth et al. 14 for example, increases in walking distance did not correlate with any increase in calf blood flow as determined by impedence plethysmography. Rosetsky et al?s could show no significant increase in Doppler-derived ankle/brachial index at the 12-week, 1-year, or 2-year follow-up period. In the present study no significant difference was found in mean ankle pressure index at the completion of 12 weeks; however, at 1- and 2-ycar follow-up statistically significant increases occurred. Although the increase in ankle brachial index was statistically significant, this difference falls within the accepted limits of error with the tecl-mique of these determinations. This may have been due to the small sample size, with the relatively stable ankle pressure measurements during the study period. Longer follow-up and larger sample size may be more helpful in determining the clinical significance of the ankle pressure changes seen with the program. Sortie and Myhre,23 Holm and Schersten,~4 and others 25'26 have suggested that rather than increasing calf blood flow, exercise affects changes in muscular metabolism, hemorrheology, and circulating coagulation factors. Therefore it may be that patients who demonstrate increased walking distances increase the metabolic efficiency of the peripheral musculature and thus compensate for their arterial insufficiency.
Elimination of patients from the rigors of exercise in the face of significant cardiac disease is of critical importance. We identified six patients before entry into the program and eight patients during supervision in phase II, for a total of 14 patients (21%) with significant cardiac disease, in whom exercise in an unmonitored situation may have proved dangerous. These numbers compare favorably with other similarly designed exercise studies,8'1°"~3'14with between I0% and 30% of patients evaluated initially being rejected. This emphasizes the importance of the graded exercise test in the evaluationof these patients. Arous et al.27 have shown that short of coronary arteriography, graded exercise testing is the most cost-effective means of detecting silent myocardial ischemia. Clinical evaluations including resting electrocardiography have been notoriously unreliable. In addition, the graded exercise test supplies the physiologic information necessary to calculate personalized prescriptions for effective, safe exercise. 12 The importance of lowering elevated blood lipid levels in patients with atherosclerosis has now been demonstrated in several well-run randomized prospective trails, z832 Most programs that emphasize exercise alone have not been able to demonstrate significant reductions in serum cholesterol or triglyceride levels. In the current study there was an emphasis on dietary modification with the aid of a registered dietician. Therefore significant reductions in cholesterol and triglyceride levels have been demonstrated at 1- and 2-year follow-up. Ornish et al. 3z have recently shown that by instituting an aggressive low-fat vegetarian diet, significant regression of angiographically demonstrated coronary stenoses can be seen. Although it is difficult to
Volume 14 Number 3 September 1991
extrapolate information from this highly motivated group of relatively young patients, it is reasonable to assume that such changes in life-style may indeed prove useful in future patients with atherosclerotic extremity occlusive disease. One of the most satisfying aspects of the current study was the elimination of smoking. Eighty-eight percent of the smokers in this study stopped by the end of the initial i2-week program. Eighty-three percent of these patients remained off tobacco at 2-year follow-up. This level of success has not been duplicated in other published studies. Most report fewer than 50% of patients ceasing tobacco use in spite of supervised modification efforts. In Rosetsky's is evaluation of patients with claudication, only one of the 12 smokers had stopped smoking by the 1-year evaluation point. Since there is strong evidence to support smoking as the most significant independent correctable risk factor for atherosclerotic vascular disease, the emphasis on cessation appears to be warranted. 33-3s Success in the current VRP may be due to the ongoing educational lectures, involvement of a trained respiratory therapist, and the goal-oriented nature of the program. However, it may well be that the social integration of the group, peer pressure, and support may have been most important. The VRP meets the challenge of presenting physical reconditioning and risk factor modification that is safer, more effective, and more palatable for patients than unsupervised exercise. The program has been operated safely without cardiac or other serious exercise-related incident. Reduction in atherosclerotic risk factors and increases in walking distances that are attained because of active intervention by the patient enhance the ability of the vascular surgeon to manage patients with lower extremity ischemic symptoms. The authors acknowledgeMonica Barnes, RN, Denise Jerwers, RN, Barbara Emmert, CRTF, and Vicki Elzer, BS, for their expertise in collecting the data necessary for this article. REFERENCES
1. Naughton J, Lategola MT, Whitsett T. Rehabilitation following myocardial infarction. Am J Med 1969;46:725-34. 2. Wenger NK. Rehabilitation of the coronary patient: stares 1986. Prog Cardiovasc Dis 1986;29:181-204. 3. Hellerstein HK, Ford AB. Rehabilitation of the cardiac patient. JAMA 1957;164:225-31. 4. Hogan CA, Neill WA. Effects of a teaching program on knowledge, physical activity and socialization in patients disabled by stable angina pectoris. J Cardiac Rehab 1982;2: 379-85.
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5. Dion WF, Grevenow P, Pollock ML, et al. Medical problems and physiologic responses during supervised inpatient cardiac rehabilitation: the patient after coronary artery bypass grafting. Heart Lung 1982;11:248-55. 6. Squires RW, Gau GT, Miller TD, Thomas GA, Lavie GJ. Cardiovascular rehabilitation: status 1990. Mayo Clin Proc 1990;65:731-55. 7. Saeterhaug A, Nygaard P. Early discharge and early rehabilitation and return to work after acute myocardial infarction. J Cardiopulm Rehab 1989;9:268-72. 8. Wisham LH, Abrahamson AS, Ebel A. Value of exercise in peripheral arterial disease, lAMA 1953;153:10-2. 9. Skinner JS, Strandness DE. Exercise and intermittent claudication: II. Effect of physical training. Circulation 1967;36:23-9. 10. Hall JA, Barnard J. The effects of an intensive 26-day program of diet and exercise on patients with peripheral vascular disease. J Cardiac Rehab 1982;2:569-74. 11. American College of Sports Medicine: guidelines for graded exercise testing and exercise prescription, 2nd ed. Philadelphia: Lea and Febiger, 1980:1-48. 12. Borg G, Linder I. A comparison between different category scales for evaluation of subjective symptoms. Report from the Institute of Applied Psychology. University of Stockholm 1979;78~ 13. Larsen DA, Lassen NA. Effect of daily muscular exercise in patients with intermittent claudication. Lancet 1966;2: 1093-6. 14. Ekroth R, Dahloff AG, GundevaU B, Holm J, Schersten T. Physical training of patients with intermittent claudication: indications, methods and results. Surgery 1978;84:640-3. 15. Rosetzsky A, Struckman l, Mathieson FR. Minimal walking distance following exercise treatment in patients with arterial occlusive disease. Ann Chir Gynaecol 1985 ;74:261-4. 16. Lundgren F, Dahloff AG, Lundholm K, Schersten T, Volkmann R. Intermittent claudication. Surgical reconstruction or physical training. Ann Surg 1989;209:346-55. 17. Kroese A. Physical activity and the peripheral circulation. Scand J Soc Med Suppl 1982;29:47-9, 18. Wright DL, Sonnenschein RR. Relations among activity, blood flow and vascular state in skeletal muscle. Am J Physiol 1965;208: 782-9. 19. Brodal P, Ingier P, Hermansen L. Capillary supply of skeletal muscle fibers in untrained and endurance-trained men. Am J Physiol 1977;232:705-12. 20. Jennings GL, Nelson L, Korner PI, Esler MD. The place of exercise in the long-term treatment of hypertension. Nephron 1987;47: (suppl. 1):30-7. 21. Nelson L, Jennings GL, Esler MD, Korner PI. Effect of changing levels of physical activity on blood pressure and haemodynamics in essential hypertension. Lancet 1986;2: 473 -6. 22. Fortmann SP. Effects of weight loss on clinic and ambulatory blood pressure in normotensive men. Am J Cardiol 1988;62: 89-92. 23. Sorlie D, Myhre K. Effects of physical training in intermittent clandication. Scan J Clin Lab Invest 1978;38:217-22. 24. Holm M, Schersten T. Metabolic changes in skeletal muscles after physical conditioning and in peripheral arterial insufficiency. Swedish J Defence Med 1974;10:71-3. 25. Ferguson EW, Bernier LL, Banta GR, et al. Effects of exercise and conditioning on clotting and fibrinolytic activity in men. J Appl Physiol 1987;62:1416-21.
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26. Stratton JR, Chandler MD, Cerqueirs MD, et al. Exercise training increases tissue plasminogen activator activity [Abstract]. Circulation 1989;80(suppl II):610. 27. Arous EJ, Baum PL, Cutler BS. The ischemic exercise test in patients with peripheral vascular disease. Arch Surg 1984; 119:780-3. 28. Lavie CJ, Gan GT, Squires KW, Kortke BA. Management of llpids in primary and secondary prevention of cardiovascular diseases. Mayo Clln Proc 1988;63:605-21. 29. O'Keefe JH, Lavie CJ, O'Keefe JO. Dietary prevention of coronary artery disease: how to help patients modify eating habits and reduce cholesterol. Postgrad Med J 1989;85:24350. 257-61. 30. O'Keefe JH, Lavie CJ, O'Keefe JO. Dietary prevention of coronary artery disease: how to help patients modify eating habits and reduce cholesterol. Postgrad Med ~ 1989;85: 257-61. 31. Coronary drug project research group: natural history of
32.
33. 34.
35.
myocardial infarction in the coronary drug project: long-term prognostic importance of serum lipid levels. Am J Cardiol 1978;42:489-98. Ornish D, Brown SE, Scherwitz LW, et al. Can lifestyle changes reverse coronary heart disease? Lancet 1990;336: 129-33. Hubner C. Exercise therapy and smoking cessation for intermittent claudication. J Cardiovasc Nurs 1987;1:50-8. Waller PC, Solomon SA, Ramsay LE. The acute effects of cigarette smoking on treadmill exercise distances in patients with stable intermittent claudication. Angiology 1989;40: 164-9. Quick CR, Cotton LT. The measured effect of stopping smoking on intermittent claudication. Br J Surg 1982; 69(suppl) :524-6.
Submitted Feb. 2, 1991; accepted Mar. 29, 1991.
Structured programs for physical reconditioning and risk factor modification have proved beneficial in patients with atherosclerotic coronary disease. 1-7 However, similar programs for patients whose initial atherosclerotic complication is peripheral arterial insufficiency have not been widely developed. This has occurred in spite of the known benefit of exercise in increasing ambulation distances and the acceptance of exercise by most vascular surgeons as a valuable tool in the management of patients with claudicafion. 8-1° The purpose of this study was to
From Saint Anthony'sHospital, St. Petersburg. Presented at the Fifteenth Annual Meeting of the Southern Association for Vascular Surgery, Palm Springs, Calif., Jan. 23-26, 1991. Reprint requests: Larry R. Williams,MD, 735 Twelfth St. N., Saint Petersburg, FL 33705. 24/6/29894 320
initiate a vascular rehabilitation program (VRP) in a cohort of patients with atherosclerosis who had a variety of lower extremity symptoms. The VRP was designed to increase exercise tolerance and reduce the risk of progressive cardiovascular disease by decreasing atherogenic risk factors. PATIENTS AND METHODS From July 1986 to July 1988, 68 patients, 32 men and 36 women, ranging in age from 55 to 85 years (mean, 68 years) were enrolled in the VRP. Thirtysix patients (53%) were admitted to the program after lower extremity revascularization operations, and two patients (3%) had undergone laser-assisted balloon dilation. After operation all 38 patients mentioned in the previous sentence continued to have intermittent claudication. The remaining 30 patients (44%) were referred with intermittent clandication and had no operative intervention (Table I).
Volume 14 Number 3 September 1991
All patients with significant claudication ( < t w o blocks) were considered suitable candidates for the program. Patients were not preselected based on the severity of their initial disability. The VRP consisted of three phases (Table II). Phase I was initiated on referral of the patient's physician, who may or may not have been a vascular surgeon. Patients underwent a comprehensive evaluation that included recording of a history and performance of a physical examination, reporting of lower extremity-Doppler derived systolic pressures and calculation of ankle/brachial indexes, a lipid profile evaluation, and identification of risk factors for atherosclerotic disease. Those risk factors noted included a significant past history of atherosclerosis or coronary artery disease, smoking or other nicotine use, hypercholesterolemia, obesity, diabetes mellitus, and hypertension (Table I). Patients then underwent graded exercise testing by use of either a treadmill or bicycle ergometer with monitoring by a physician. This test was done to detect underlying cardiac disease and provided information required for calculating the individual exercise prescription. If significant underlying silent cardiac disease was discovered, the patient was referred for further cardiologic evaluation and not enrolled in the VRP. Once the patient successfully completed the graded exercise test, phase II commenced with preparation of an initial rehabilitative physical exercise prescription by use of guidelines established by the American College of Sports Medicine. 11 Resting heart rate, maximum heart rate, and metabolic equivalent of oxygen consumption determined from the graded exercise test were used to calculate net and training oxygen consumption and training metabolic equivalent of oxygen consumption. Entry levels for initiation of exercise training were set at 50% of functional capacity; exercise activities were selected for variety and to accommodate specific patient limitations according to known energy expenditures at the desired exercise levels.l~ Activities included use of the treadmill for walking, stationary bicycle, steps, arm crank, and rowing machine and free weights. These were set up as stations to be performed during each training session. At each station patients measured heart rate, time to onset of symptoms, maximum exercise time, and subjective "difficulty" using the 1 to 20 Rating of Perceived Exertion scale developed by Borg? 2 The exercise session, outlined in Table III, included check-in with resting heart rate, blood pressure, and weight; warmup; individual work stations; and cool-down periods. The 12-week program consisted of a minimum of 24 physical
Vascular rehabilitation 321
Table I. Admission diagnosis and risk factors Claudication (Nonoperated) Clandication (Postrevascularization) Aortofemoral Infrainguinal Dilation Risk factors Smoking Hypertension Diabetes mellitus Previous myocardial infarction Hypercholesterolemia Stroke Obesity
30 (44%) 38 (56%) 6 (9%) 3 0 (44%) 2 (3%) 56 (82%) 34 (50%) 18 (26%) 24 (24%) 16 (18%) 4 (6%) 4 (6%)
Table II. Vascular rehabilitation Phase I Referral by physician History and physical examination Risk factor profile Cholesterol/triglyceride analysis Segmental Doppler pressures Graded exercise testing (cardiac stress test) Phase II Initial rehabilitation exercise prescription 12-week program of exercise, education, monitoring Phase III Home maintenance program Periodic assessment and modification
reconditioning sessions (two 1-hour sessions per week). The patients .also underwent 12 (1-hour) personalized education lectures for reduction and control of athcrosclerotic risk factors. Specific topics addressed included hypercholesterolemia, diabetes mellitus, and overview of atherosclerosis, smoking reduction, and education regarding claudication and vascular operations as applicable. These lectures were supplemented with additional individual consultation with a registered dietician, respiratory therapist, exercise physiologist, nurse, or physician as necessary. Smoking cessation classes were maintained for ongoing support to initiate and maintain abstinence from tobacco. Plans were also developed at this time for a home maintenance exercise program. Guidelines for patient completion of the VKP were (1) improvement in exercise tolerance, (2) delayed onset and decreased severity of claudication to a level that had a minimal effect on walking ability, (3) understanding of safe exercise practices and guidelines for a home maintenance program, (4) development of a regular exercise regimen at home and a commitment to continue this practice, (5) attendance at all educational lectures and (6) correct
322
Journal of VASCULAR SURGERY
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Table III. Exercise session Minutes Check-in, resting pulse, blood pressure, weight, warm-up.routine Work stations ~ Cool-down, stretching Total body relaxation Total
10 35 10 5 60
~Recordings at each station: heart rate, time to development of first symptoms, maximum exercise time, rate of perceived exertion (Borg12).
identification of the signs, symptoms, and proper management of the risks of atherosclerosis. These guidelines were helpful in determining when patients could safely advance to their home maintenance program (phase III); however, they were not strictly interpreted as success or failure within the program. Patients were evaluated at entry level, 6 weeks, 12 weeks, and every 3 months on an ongoing basis. Walking distance measurements were recorded as time to development of first symptoms and maximum walking time. Percentage increases in walking time were determined, and Doppler-derived ankle/brachial systolic pressure indexes were calculated. Serum cholesterol and triglyceride determinations were made as milligrams per deciliter after a 12-hour overnight fast. Personal questionnaires were completed to ascertain adherence to diets, smoking cessation, and home exercise programs. Data were analyzed by use of a mixed analysis of variance (ANOVA) with gender as the between variable and time as the within variable. Schefe a posteriori analysis was used to determine significant differences at each time interval. Differences were considered significant at the L0.01 confidence level. The VRP was approved by the St. Anthony's Hospital Institutional Review Board. All patients were thoroughly informed and gave appropriate consent in writing before evaluation and entry into the program. RESULTS
Six (9%) of the 68 patients initially evaluated (phase I) for the program were found to have significant cardiac disease on the graded exercise test, in spite of the fact that patients with known symptomatic coronary occlusive disease were not accepted for evaluation. These six patients were referred back to their primary physician for consideration of further cardiologic consultation. The
remaining 62 patients entered phase II of the program (monitored exercise and risk factor modification). No deaths or major morbidity occurred. Seventeen patients (27%) did not complete the 12-week program. Nine of these patients left the program for nonmedicai reasons: four moved from the area, three stated only that they did not like the program or had scheduling conflicts, and two gave no reason. Eight patients (13%) left the program because of the development or recognition of significant cardiovascular problems. Four problems were cardiac related: exercise limiting angina developed in three patients midway through the program, and shormess of breath as a result of congestive heart failure developed in one patient. After consultation with their referring physicians, they were excluded from the program for further medical treatment. Difficulties with their extremities developed in two patients. One patient was actually unaware that her femoropopliteal bypass graft was acutely thrombosed until her exercise session reproduced her original daudication at a very short distance. After thrombectomy she was eventually readmitted to the program. Increasingly severe symptoms in the opposite leg developed in another patient, and she dropped out of the program for revascularization of that extremity. Transient ischemic attacks developed in two patients while they were in the program, and they were referred for further cerebrovascular evaluation (Table IV). Forty-five patients graduated from the 12-week phase II program. All 45 (100%) designed a home maintenance program for exercise and continued surveillance of their specific risk factor modifications (phase III), and all have had formal evaluations every 3 months. Nineteen patients (42%), however, found the organized program more stimulating and chose to continue in phase II for one or more (up to six) additional 12-week periods before advancing to their phase III program. Thirty-eight patients (84%) have been followed for at least 24 months, and 35 (92%) of these have maintained their regular phase III programs. All 35 have avoided any further extremity, cardiac, or cerebrovascular symptoms, and no one has required rehospitalization for cardiovascular related illness. Two patients moved from the area and lost interest, and one patient died of lung cancer. Walking distance All 45 patients who completed the phase II program had significant increases in walking distances measured both as the time to development of
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Table IV. Patient progress 68 Patients initially considered 6 (9%) Significant cardiac disease at initial evaluation (phase I) 17 (27%) Started the program and dropped out during phase II 8 - Nonmedical reasons 3 - Angina 1 - Congestive failure 2 - Extremity ischemia 2 - Cerebrovascular symptoms 45 (66%) Graduates from phase II 45 (100%) Development of phase III programs
first calf or thigh pain and maximum walking distance (Table V). Symptom-ftee walking time increased an average of 107% at the completion of phase II. This improvement was maintained at the 1- and 2-year follow-up points with no significant continued improvement. Maximal walking time increased an average of 210% at the completion of phase II, however, it showed an additional significant increase at the 1-year point. No additional improvement was noted at 2 years. At long-term follow-up, walking distances recorded at exit were maintained or improved in 84% of the patients. Ankle/brachial index Although in some patients increased walking distances at the completion of phase II were accompanied by increases in the Doppler-derived ankle/brachial blood pressure indexes, this was not the rule. As depicted in Table VI, anlde/brachial indexes were not significantly different on average at the completion of phase II. At the 1-year follow-up significant increases were found in the mean ankle pressures. No difference was found between measurements at 1 and 2 years. Although a wide range (0.31 to 0.71) was found in the ankle/brachial indexes across the group, individual patient anlde/brachial indexes were relatively stable during the total evaluation time. Improved walking distances were noted regardless of whether the patients had undergone prior revascularization operations or had never been operated on. Serum lipid profile At the completion of phase II (12 weeks) significant reductions were seen in serum triglyceride levels (Table VII). Additional significant lowering was seen at 1-year follow-up, and this was maintained at the 2-year evaluation. Although many patients demonstrated reductions in cholesterol levels at the 12-week point, the results for the group were not
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Table V. Walking distances ~ % Increase
12 Weeks
Symptom-free walking Range 62%-320% Mean 107% Maximum walking Range 53%-450% Mean 210%
1 Year
2 Years
83%-411% 149%
91%-402% 178%
59%-600% 272%
61%-522% 257%
~Measured as treadmill walking times.
statistically significant. However, significant reductions in cholesterol were seen at the 1-year point, with no significant continued reduction at 2 years. Smoking The response to smoking cessation emphasis was gratifying; 36 of the 41 smokers (88%) stopped smoking. Long-term (2-year) abstinence from tobacco products was maintained in 30 of these patients (83%). DISCUSSION
Regular physical exercise is widely recommended and generally accepted as a valuable intervention in patients with a variety of symptoms caused by atherosclerosis. Many organized programs have been developed to aid patients in their recovery from myocardial infarction and coronary artery bypass surgery. 1-8 However, similar patients, often with identical risk factors and disease distribution, who are more limited by their lower extremity arterial insufficiency, are often given little or no assistance in modifying their life-styles to avoid future atherosclerotic complications. The VRP here outlined has successfully met this challenge. Exercise tolerance measured as both symptom-free and maximal walking times were significantly increased, with these benefits maintained over a 2-year follow-up. These results compare favorably with previously described exercise studies. Larsen and Lassen 13showed a 300% average increase in walking distance in patients in an organized walking class, as compared to a control group who exhibited no change. Ekroth et al?4 studied 148 patients with intermittent claudication in a 6-month training program. Walking ability increased in 88% of patients with an average increase of 234% in maximal walking distance. Rosetsky et al? s likewise showed significant improvements in walking distance with organized exercise instruction in patients with intermittent claudication. Lundgren et a1.16 recently reported the additive beneficial effect of lower
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Table VI. Doppler ankle/brachial indexes Range Mean
Baseline
12 Weeks
1 Year
2 Years
0.33-1.00 0.73
0.31-1.00 0.75
0.35-1.00 0.78*
0.35-1.00 0.78*
*p < 0.01. Table VII. Serum lipid profile Cholesterol (mg/dl) Range Mean Triglycerides (mg/dl) Range Mean
Baseline
12 Weeks
1 Year
2 Years
156-446 286
152-396 270
144-260 222*
151-251 210"
172-735 382
156-522 310"
143-400 262*
140-352 240*
*p < 0.01.
extremity revascularization and subsequent exercise training when compared with operation or exercise training alone. Although some have suggested that this increased exercise ability is due to increased peripheral blood flow and/or development of collateral circulation or increased numbers of capillaries, ~7-~9this view is not unanimous. 2°-22 In the study of Ekroth et al. 14 for example, increases in walking distance did not correlate with any increase in calf blood flow as determined by impedence plethysmography. Rosetsky et al?s could show no significant increase in Doppler-derived ankle/brachial index at the 12-week, 1-year, or 2-year follow-up period. In the present study no significant difference was found in mean ankle pressure index at the completion of 12 weeks; however, at 1- and 2-ycar follow-up statistically significant increases occurred. Although the increase in ankle brachial index was statistically significant, this difference falls within the accepted limits of error with the tecl-mique of these determinations. This may have been due to the small sample size, with the relatively stable ankle pressure measurements during the study period. Longer follow-up and larger sample size may be more helpful in determining the clinical significance of the ankle pressure changes seen with the program. Sortie and Myhre,23 Holm and Schersten,~4 and others 25'26 have suggested that rather than increasing calf blood flow, exercise affects changes in muscular metabolism, hemorrheology, and circulating coagulation factors. Therefore it may be that patients who demonstrate increased walking distances increase the metabolic efficiency of the peripheral musculature and thus compensate for their arterial insufficiency.
Elimination of patients from the rigors of exercise in the face of significant cardiac disease is of critical importance. We identified six patients before entry into the program and eight patients during supervision in phase II, for a total of 14 patients (21%) with significant cardiac disease, in whom exercise in an unmonitored situation may have proved dangerous. These numbers compare favorably with other similarly designed exercise studies,8'1°"~3'14with between I0% and 30% of patients evaluated initially being rejected. This emphasizes the importance of the graded exercise test in the evaluationof these patients. Arous et al.27 have shown that short of coronary arteriography, graded exercise testing is the most cost-effective means of detecting silent myocardial ischemia. Clinical evaluations including resting electrocardiography have been notoriously unreliable. In addition, the graded exercise test supplies the physiologic information necessary to calculate personalized prescriptions for effective, safe exercise. 12 The importance of lowering elevated blood lipid levels in patients with atherosclerosis has now been demonstrated in several well-run randomized prospective trails, z832 Most programs that emphasize exercise alone have not been able to demonstrate significant reductions in serum cholesterol or triglyceride levels. In the current study there was an emphasis on dietary modification with the aid of a registered dietician. Therefore significant reductions in cholesterol and triglyceride levels have been demonstrated at 1- and 2-year follow-up. Ornish et al. 3z have recently shown that by instituting an aggressive low-fat vegetarian diet, significant regression of angiographically demonstrated coronary stenoses can be seen. Although it is difficult to
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extrapolate information from this highly motivated group of relatively young patients, it is reasonable to assume that such changes in life-style may indeed prove useful in future patients with atherosclerotic extremity occlusive disease. One of the most satisfying aspects of the current study was the elimination of smoking. Eighty-eight percent of the smokers in this study stopped by the end of the initial i2-week program. Eighty-three percent of these patients remained off tobacco at 2-year follow-up. This level of success has not been duplicated in other published studies. Most report fewer than 50% of patients ceasing tobacco use in spite of supervised modification efforts. In Rosetsky's is evaluation of patients with claudication, only one of the 12 smokers had stopped smoking by the 1-year evaluation point. Since there is strong evidence to support smoking as the most significant independent correctable risk factor for atherosclerotic vascular disease, the emphasis on cessation appears to be warranted. 33-3s Success in the current VRP may be due to the ongoing educational lectures, involvement of a trained respiratory therapist, and the goal-oriented nature of the program. However, it may well be that the social integration of the group, peer pressure, and support may have been most important. The VRP meets the challenge of presenting physical reconditioning and risk factor modification that is safer, more effective, and more palatable for patients than unsupervised exercise. The program has been operated safely without cardiac or other serious exercise-related incident. Reduction in atherosclerotic risk factors and increases in walking distances that are attained because of active intervention by the patient enhance the ability of the vascular surgeon to manage patients with lower extremity ischemic symptoms. The authors acknowledgeMonica Barnes, RN, Denise Jerwers, RN, Barbara Emmert, CRTF, and Vicki Elzer, BS, for their expertise in collecting the data necessary for this article. REFERENCES
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Submitted Feb. 2, 1991; accepted Mar. 29, 1991.