Pathophysiology of venous claudication

Transcription

1 ORIGINAL ARTICLES Pathophysiology of venous claudication Lois A. Killewich, Ph.D., Robert Martin, B.S., Miles Cramer, B.S., Kirk W. Beach, M.D., and D. Eugene Strandness, Jr., M.D., Seattle, Wash. Patients with chronic iliofemoral venom obstruction may develop severe thigh pain and a sensation of tightness with vigorous exercise (venom daudication). The discomfort requires 15 to 20 minutes to subside. In the seven patients studied the venom capacitance (VC) and venous outflow (VO) are lower than those of the unaffected limb even at rest. With exercise to the point of pain, the VO was unchanged but the VC decreased even further. The problem appears to rest with the venom collaterals, which have a high and fixed resistance. Became of this high outflow resistance, venom volume increases to near maximum during exercise. With this rise in venom volume, the amount the VC can increase during the period immediately following exercise is further reduced. (J VASC SURG 1984; 1: ) The commonly recognized symptoms and signs of the postthrombotic syndrome include pain with prolonged standing, edema, hyperpigmentation, and ulceration. It now appears that there is a subgroup of patients who, in addition to having one or more of the commonly observed symptoms, also develop severe thigh pain with strenuous exercise. This symptom complex, referred to as venous claudication, has been described only rarely in the literature, and little is currently known about its pathophysiology. It was first reported by Cockett et al., ~ who described calf pain that developed within 5 minutes of a "stepping" test. These authors claimed that it occurred only in patients with a chronic obstruction involving the ileofemoral venous segment. The symptoms did not ~ccur in patients with either valvular incompetence "or postthrombotic occlusion of the peripheral deep veins. Furthermore, they suggested that it might be relieved by a graft bypassing the obstructed area. Hobbs 2 subsequently reported one case of venous claudication associated with iliofemoral venous obstruction and an elevated femoral vein pressure that was increased even further during exercise. Since 1981 we have identified seven patients whose histories are compatible with the diagnosis of venous claudication. The patients develop severe thigh pain and the sensation of tightness with exer- From the Section of Vascular Surgery, Department of Surgery, University of Washington School of Medicine. Supported by National Institutes of Health grant No Reprint requests: D. E. Strandness, Jr., M.D., Department of Surgery, RF-25, University of Washington, Seattle, WA cise. In contrast to claudication secondary to arterial disease, 15 to 20 minutes rest combined with elevation of the legs is often required to obtain relief from the pain. In addition, the development of the pain may be accompanied by the appearance of cyanosis, a sensation of further swelling, and increased prominence of the superficial veins in the thigh. The purpose of this report is to present our experience with these patients and to review the physiologic changes that occur at rest and after graded treadmill exercise to the point of pain. MATERIAL AND METHODS The seven patients in this study included three men and four women. The ages ranged from 21 to 43 years (mean age 33 years). The onset of deep venous thrombosis was related to the following events: trauma (two patients), cesarean section (two), pregnancy (one), brain abscess with subsequent immobilization (one), and mukiple sclerosis (one). The extent of the deep venous thrombosis was classified by the most proximal level of involvement and included the left iliofemoral segment in six patients and the complete right leg in one. Patients were seen from one to six times for evaluation, and the duration of follow-up ranged from 2 months to 7 years. At each visit, ankle, calf, and thigh circumferences were measured at 5, 25, and 55 to 65 cm, respectively, above the medial malleolus. Venous outflow (VO) measured over the interval of 0.5 to 2 seconds and venous capacitance (VC) measured at 2 minutes were measured by strain gauge plethysmog- 5O7

2 508 Killewich et al. % Rise = ~~_S!_:JLe...2._ ~.~ BaselineExercise ~ ~ '''"... ~ "~]" -- chart speed : 6 mm/sec Tp,,s _... Fig. 1. Parameters used for calculations include, A, initial refilling rates (percent rise at 3 seconds) and, B, venous refilling time (VRT) and half peak time (Tip). Points at which these measurements are made are illustrated. raphy as described previously, a According to this method, patients are placed in the supine position with feet elevated 27 cm above the back. The strain gauge is placed around the maximum circumference of the calf, and a pneumatic cuffis placed around the thigh. The thigh cuff is inflated to 55 mm Hg to occlude VO, and VC is measured after 2 minutes. The cuffis then rapidly deflated and VO is measured over the time interval of 0.5 and 2 seconds. After resting values were recorded, patients were then exercised on a treadmill until forced to stop because of pain, at which time VO and VC were remeasured. The level and extent of valvular incompetence was assessed by continuous-wave Doppler analysis and the photoplethysmograph. Valvular incompetence can be assessed at any level of the limb by the demonstration of reverse flow when the limb proximal to the Doppler transducer is forcibly compressed. The photoplethysmograph is used to monitor the skin blood volume changes just proximal to the medial malleolus that occur following four rhythmic compressions of the calf. These studies are done with the patient in the sitting position and the feet in contact with the floor. The calf compression is carried out by inflating a cuffplaced about the calf at its point of greatest circumference to a level of 60 mm Hg 4. It has been shown that the changes in skin blood volume assessed by this method correlated closely with the time varying changes in venous pressure that occur with exercise. The measurements used include venous recovery time (VRT), the half peak time (T½v), and the time to Journal of VASCULAR SURGERY Table I. Ankle, calf, and thigh circumferences in affected and unaffected limbs (in centimeters) Unaffected Affected Ankle _ Calf Thigh ± _ _ (p < o.o5) return to the level before exercise or the percent rise at 3 seconds (Fig. 1). 4-7 These tests are done before and after application of a tourniquet, which is used to occlude the superficial veins. All data were analyzed by paired t tests. RESULTS Table I shows a comparison of the ankle, calf, and thigh circumferences in the seven patients under resting conditions. The mean ankle circumference of the affected limbs was 0.28 _ cm larger than the ankle circumference of the unaffected limbs. At the calf there was a mean increase of cm in the affected vs. unaffected limbs and at the thigh a mean increase of cm in the affected vs. unaffected limbs. The changes in ankle circumferences were not significant ; however, the increases at the level of the calf and thigh were significant. Table II shows the results of VO and VC measurements under resting conditions. Both the VO, measured at 0.5 to 2 seconds, and the VC, measured at 2 minutes, were significantly lower in the affected leg. The VO was decreased by ml/100 cc oftissue/min, and the VC was decreasf') by ml/100 cc of tissue. The amount of exercise required to elicit thigh pain is shown in Table III. As noted, varying from 8 minutes at 3 mph and a 15% grade to 341k minutes at 3 mph and a 19% grade, this is excessive. The~ average was 161/2 minutes at 3 mph and a 14% grade. Although this is unusual, it is consistent with the activities these patients were accustomed to carrying out--including tennis, downhill skiing, and jogging. The effect of exercise on VO (0.5 to 2 seconds) and VC (2 minutes) in the normal and affected limbs is summarized in Table IV. In the unaffected limbs there were no significant changes in these two parameters with exercise. In the affected limbs VC (2 minutes) decreased from ml/ 100 cc of tissue to ml/100 cc of tissue

3 Volume 1 Number 4 July 1984 Pathophysiology of venous daudication 509 Table II. Resting VO and VC in unaffected and affected limbs Unaffected Affected VO (0.5-2 sec) _ (ml/100 cc of tissue/rain) VC (2 rain) _ _ (ml/100 cc of tissue). The values for VO were essentially unchanged. The results of the photoplethysmographic measurements to document the status of deep venous valves are shown in Table V. It can be seen that both VRT and the T~p were decreased in the affected limbs relative to the unaffected limbs, regardless of whether the tourniquet was used to occlude the su- (erficial veins. Conversely, the percent rise was increased in the affected limbs with and without the tourniquet. All values were significant at the p < 0.05 level. These findings are consistent with valvular incompetence of the deep venous system. Doppler ultrasound measurements were made on six of the seven patients, and in each case valvular incompetency was present in either the superficial femoral, popliteal, or posterior tibial veins. DISCUSSION In this study we explored the physiologic changes leading to the development of venous claudication in patients with the postthrombotic syndrome as well as the effects of exercise on measurements of venous function in the unaffected limbs. We were unable to demonstrate any effects of exercise on VO and VC in normal limbs. Arterial flow must be at. ~ar maximal levels immediately following exercise, and venous flow must be equal to inflow. Although it might appear that there should be changes in VO measured at 0.5 to 2 seconds and VC measured at 2 minutes associated with the changes in total limb blood flow, this is not necessarily the case, given the methods used to make these measurements. The measurement of VC as performed is only an index of the maximum increase in volume that can occur at the calf level when venous return at the thigh level is occluded for 2 minutes. Likewise, the determination of VO at 0.5 to 2 seconds is a measure of the rate of venous emptying on release of the thigh cuff and is not analogous to the amount of the venous flow. It should be noted that our findings are in contrast to those oftripolitis et al.,s who measured VO and VC in a single patient with postthrombotic syndrome and venous claudication. They found that in the ten- Table III. Treadmill experience to venous claudication Patient Speed Time to claudication No. (mph) % Grade (rain) affected limb, exercise caused an increase in VO. It is possible that the difference in results is due to the slightly different methods for measuring VO and VC at the time. Chronic iliofemoral venous obstruction leads to two problems that may explain the mechanism responsible for the pain and the observed fall in VC (2 minutes) in the affected limbs of the patients with venous claudication. The collaterals that bypass the area of occlusion clearly have a greater resistance to flow than those in the normal limb. This is seen by the lower resting VO (0.5 to 2 seconds) in the affected limbs relative to the unaffected limbs. The fact that it did not change after exercise suggests that collateral resistance is fixed and not affected by the changes in either arterial inflow or venous return associated with exercise. On the other hand, the VC (2 minutes) decreased, which seems paradoxical. Although we did not measure femoral vein pressures, the case reported by Hobbs 2 showed a dramatic rise in pressure with exercise in the affected limb but only a slight rise in the normal limb. Moreover, Bjordal 9 has reported two cases of iliofemoral obstruction and venous claudication associated with increased saphenous venous pressures. A rise in pressure will occur when there is an increase in blood flow and a high, fixed outflow resistance offered by the venous collaterals. As the femoral vein pressure rises, an increase in venous volume must also occur. This volume increase may also explain patients' complaints of "tightness" that occur in conjunction with the pain. If one assumes that the

4 51 0 Killewich et al. Journal of VASCULAR SURGERY Table IV. VO and VC before and after exercise in unaffected and affected limbs Before exercise After exercise Change Unaffected limbs VO (0.5-2 sec) ± 6.14 (ml/100 cc of tissue/rain) VC (2 rain) 3.18 _ ± 0.46 (ml/100 cc of tissue) Affected limbs VO (0.5-2 sec) ± ± (rnl/100 cc of tissue/rain) VC (2 rain) 2.36 ± ± 0.63 (ml/100 cc of tissue) ± ± ± 0.60 Table V. Results of photoplethysmography in unaffected and affected limbs of patients with venous claudication Unaffected Affected VRT Without tourniquet ± With toumiquet T½P Without tourniquet _ With tourniquet ± ± 4.47 % rise at 3 sec Without tourniquet ± ± With tourniquet ± ± venous volume is near maximal levels during the period immediately following exercise, then the amount it could further increase with inflation of the thigh cuff would have to be less than that observed at rest leading to a decreased VC. To compound this problem further, there may well be an increase in the volume of interstitial fluid, which requires several minutes to equilibrate after the exercise has been stopped. Dodd and Cockett TM describe the type of postthrombotic syndrome observed in the patients reported in this study as "the above the inguinal ligament type." Because these proximal veins rarely recanalize, venous return occurs only via the collaterals. As a consequence, patients develop "pseudohypertrophy" of both the thigh and calf, which these authors believe represents chronic intramuscular edema. Certainly all the patients in our series had larger thighs and calves, which did not vary during the day or from visit to visit. Whereas Dodd and Cockett 1 noted that the veins distal to the inguinal ligament remained nor- mal with intact, competent valves, the panents m this series demonstrated incompetence at one or more levels of the limb. This does not appear to be a major contributing factor to the development of venous claudication since this problem most likel" rests with the high-resistance venous collaterals. These patients may be candidates for a venous crossover bypass graft to decompress the venous system in the involved limb. To date, this has not been recommended since the discomfort these patients experience only occurs with recreational activity of the most vigorous type. In fact, they are able to carry out their usual daily activities without difficulty. Four of the patients continue to participate in the activity that produces the discomfort. One continues to compete as a world-class downhill skier; when the pain becomes severe, he elevates the limb to a vertical position and has a companion vigorously massage the calf and thigh until the discomfort disappears. Elastic support has been tried in these patients but does not appear to provide any symptomatic

5 Volume 1 Number 4 July 1984 Pathophysiology of venom claudication 511 benefit. This is not surprising, since there is no evidence that gradient stockings do anything more than assist in the control of edema, which is not a problem in these patients. Graduated exercise training was tried in one patient who had been a competitive jogger to see if his exercise tolerance could be improved. There was alleged improvement, but this was impossible to quantitate. REFERENCES 1. Cockett FB, Thomas ML, Negus D. iliac vein compression-its relation to ile0femoral thrombosis and the postthrombotic syndrome. Br Meal J 1967; 2: Hobbs JT. The postthrombotic syndrome. In: Hobbs yr, ed. The treatment of Venous disorders. Philadelphia: JB Lippincott Co, 1977: Cramer M, Langlois Y, Beach K, Martin D, Strandness Jr DE. Standardization of venous flow measurement by strain.~. gauge plethysmography: The definition of normality. Presented at the Fifth Annual Scientific Session of the Society of Noninvasive Vascular Technologists, Boston, Mass., June 14-16, Abrarnowitz HB, Queral LA, Flinn WR, Nova PF, Peterson LK, Bergan JJ, Yao JST. The use of photoplethysmog~aphy in the assessment of venous insufficiency: A comparison to venous pressure measurements. Surgery 1979; 86: Gorsuch MS, Kempczinski R. Role of photoplethysmography in the evaluation of venous insufficiency. Bruit 1981; 5: Kingston V, Moore DJ, Shanik DG. Has photoplethysmography a role to play in the assessment of treated venous disease? Bruit 1982; 6: Matin RL, Langlois YE, Martin DC, Jager KA, Beach KW, strandness Jr DE. Variability of photoplethysmography measurements in normals utilizing a standard exercise protocol. Abstract for the Society of Noninvasive Vascular Technology, San Francisco, Calif., June 12-15, Tripolitis AJ, Milligan EB, Bodily KC, Strandness Jr DE. The physiology of venous claudication. Am J Surg 1980; 139: Bjordal RI. Intermittent venous claudication: A report of two :cases. Acta Chir Scand 1970; 136: Dodd H, Cockett FB. The pathology and surgery of the veins of the lower limb, ed 2. Edinburgh: Churchill Livingstone, 1976:263. BOUND VOLUMES AVAILABLE TO SUBSCRIBERS Bound volumes of the JOURNAL OF VASCULAR SURGERY for 1984 are available to subscribers only. Active members of the two sponsoring societies will automatically receive a complimentary bound volume. They may be purchased from the publisher at a cost of $24.75 ($32.50 international) for Vol. 1 (January to December). Price includes shipping charges. Each bound volume contains a subject and author index, and all advertising is removed. Copies are shipped within 30 days after publication of the last issue in the volume. The binding is durable buckram with the journal name, volume number, and year stamped in gold on the spine. Payment must accompany all orders. Contact Circulation Fulfillment, The C. V. Mosby Company, Westline Industrial Drive, St. Louis, MO 63146, USA. In the United States call toll free: (800) , ext In Missouri call collect: (314) , ext Subscriptions must be in force to qualify. Bound volumes are not available in place of a regular JouRNAL subscription.