Assessment of intermittent claudication by means of the transcutaneous oxygen tension exercise profile

Discordance of peripheral artery disease diagnosis using exercise transcutaneous oxygen pressure measurement and post-exercise ankle-brachial index

In patients with exertional limb symptoms and normal ankle-brachial index (ABI) at rest, exercise testing can be used to diagnose lower extremity arterial disease (LEAD). Post-exercise ABI decrease or Exercise transcutaneous oxygen pressure measurement (Exercise-TcPO2) can be used to diagnose LEAD. Objectives were (i) to assess the agreement between both methods (ii) to define the variables associated with the discordance, and (iii) to present results of healthy subjects. In this prospective cross-sectional study, patients with exertional limb symptoms and normal rest ABI were consecutively included. ABI was measured at rest and after standardized exercise protocol as well as Exercise-TcPO2. A kappa coefficient with a 95% confidence interval was used to assess the agreement between the two methods. Logistic regression analysis was performed to outline variables potentially responsible for discordance. Ninety-six patients were included. The agreement between the tests was weak with a k value of 0.23 [0.04–0.41]. Logistic regression analysis found that a medical history of lower extremity arterial stenting (odds ratio 5.85[1.68–20.44]) and age (odds ratio 1.06[1.01–1.11]) were the main cause of discordance. This study suggests that post-exercise ABI and Exercise-TcPO2 cannot be used interchangeably for the diagnosis of LEAD in patients with exertional symptoms and normal rest ABI.

Functional outcome of hypogastric revascularisation for prevention of buttock claudication in patients with peripheral artery occlusive disease

We have defined proximal lower limb ischaemia as a decrease in Exercise-transcutaneous oxygen pressure (TcPO(2)) lower than minus 15mmHg at the buttock level in patients with peripheral artery occlusive disease. The purpose of this study was to objectively evaluate the benefits of direct versus indirect revascularisation of internal iliac arteries (IIAs) for prevention of buttock claudication in this population. We retrospectively reviewed the charts of proximal ischaemia patients who underwent revascularisation and both preoperative and postoperative stress TcPO(2) testing. Revascularisation procedures were classified as either direct revascularisation, including percutaneous transluminal angioplasty and internal iliac artery bypass, resulting in a direct inflow in a patent IIA (group 1) or indirect revascularisation, including aortobifemoral bypass and recanalisation of the femoral junction on the ischaemic side, resulting in indirect inflow from collateral arteries in the hypogastric territory (group 2). Patency was checked 3 months after revascularisation in all cases. Treadmill exercise stress tests were performed before and after revascularisation using the same protocol designed to assess pain, determine maximum walking distance (MWD) and measure TcPO(2) during exercise. In addition, ankle-brachial indices (ABIs) were calculated. Between May 2001 and March 2008, a total of 93 patients with objectively documented proximal ischaemia underwent 145 proximal revascularisation procedures using conventional open techniques in 109 cases and endovascular techniques in 36. Direct revascularisation was performed on 50 limbs (35%) (group 1) and indirect revascularisation on 95 limbs (65%) (group 2). The mean interval between revascularisation and stress testing was 60+/-74 days preoperatively and 149+/-142 days postoperatively. No postoperative thrombosis was observed. Buttock claudication following revascularisation was more common in group 2 (p<0.001). No difference was observed between the two groups with regard to improvement in MWD (365 / 294 m) and ABI (0.20/0.22). Disappearance of proximal ischaemia was more common after direct revascularisation (p<0.01). The extent of lesions graded according to the TASC II classification appeared not to be predictive of improvement in assessment criteria following revascularisation. Conversely, patency of the superficial femoral artery was correlated with improvement (p<0.01). This study indicates that direct revascularisation, if feasible, provides the best functional outcome for prevention of buttock claudication.

High prevalence of proximal claudication among patients with patent aortobifemoral bypasses

BACKGROUND

Proximal (ie, buttock, hip) claudication can result from impaired perfusion in the hypogastric area after aortobifemoral bypass (ABF) despite normal femorodistal blood flow provided by the patent bypass. The proportion of patients that experience proximal claudication after ABF is unknown, and arguments for the vascular origin of symptoms specifically at the proximal level have never been reported.

METHODS

This was a prospective study set in an institutional practice of ambulatory patients referred for a systematic survey of their previous ABF bypass. Among the 131 eligible patients, 10 refused to participate and 16 were unable to walk on a treadmill. The 105 studied patients (94 men, 11 women) were a mean age of 63 +/- 10 years, and the median delay from surgery was 2 years (range, 4 months to 26 years). We used a modified version of the San Diego Claudication Questionnaire administered both at rest before the treadmill study and again after the treadmill test. Transcutaneous oxygen pressure (TcPO2) at the buttock level was used to evaluate blood flow impairment during exercise at the proximal level, with blood flow impairment defined as buttock minus chest TcPO2 decrease in excess of -15 mm Hg.

RESULTS

Thirty patients reported proximal exercise-related pain consistent with vascular criteria by history before exercise. However, 59 patients (56%) reported symptoms compatible with proximal claudication, and TcPO2 values were abnormal on one or both sides in 52. The persistence of at least one (prograde or retrograde) pathway to the hypogastric circulation, determined by review of operative details from the aortobifemoral bypass and angiography, did not significantly decrease the proportion of patients reporting proximal claudication by history (26%) or on treadmill (55%) compared with those with bilateral hypogastric occlusion (33% by history, P = .51 compared with at least one prograde hypogastric pathway and 61% based on treadmill test, P = .65 compared with at least one prograde hypogastric pathway).

CONCLUSION

The present study shows that (1) the proportion of ABF patients with a median bypass age of 2 years that report proximal claudication is high (28%), (2) this proportion is significantly higher when claudication is detected by treadmill exercise tests, (3) a vascular origin (or at least contribution) is likely 88% of the proximal symptoms observed on treadmill, (4) the presence of proximal claudication with associated abnormal TcPO(2) results increases the risk of walking impairment in affected patients, and (5) preservation of at least one internal iliac artery to allow prograde or retrograde flow to the hypogastric vascular bed does not decrease the risk of proximal claudication after ABF surgery. A vascular origin of (or at least contribution to) most of the proximal exercise-related symptoms should always be discussed in patients with patent ABF bypass.

Past, Present and Future of Arterial Endofibrosis in Athletes

Exercise-induced arterial endofibrosis (EIAE) is now a 20-year-old concept. Initially observed in highly trained cyclists, it has been found in many other male and female endurance athletes. Most stenoses are located on the first centimetres of the external iliac artery but other localisation may be found. The disease is defined by specific histological findings showing fibrosis of the intimal and medial wall of the artery. Ankle pressure measurement plays a key role in the diagnosis of EIAE provided that the exercise tests reproduce symptoms and are performed with the subject being highly trained, and that pressure measurements are performed early following exercise. Various cut-off values have been proposed in the literature. Magnetic resonance imaging or arteriography or ultrasound imaging should be performed by trained operators only. Surgical 'endofibrosectomy' is preferable in young cyclists generally associated with a saphenous enlargement patch. We do not recommend angioplasty. Athletes are generally allowed to return to competition within 3-4 months following surgery. Many unanswered questions remain, specifically about the pathophysiology of this disease. Mechanical and pressure strain play a central role in the development of EIEA, but nutritional and haemorrheological factors, hormonal changes and a genetic predisposition are likely to contribute. New techniques could facilitate the diagnosis of EIAE.

Transcutaneous oxygen pressure measurements on the buttocks during exercise to detect proximal arterial ischemia: comparison with arteriography

BACKGROUND

We sought to identify whether transcutaneous oxygen tension (tcPo2) measurements could be used to noninvasively detect lesions in the arterial network supplying blood flow to the hypogastric circulation.

METHODS AND RESULTS

A study was undertaken in vascular patients with suspected (PC, n=43) and not with suspected (NPC, n=34) proximal ischemia. TcPo2 was measured on both buttocks and with a chest reference electrode. Arteriography on the right or left side was positive for stenoses (> or =75%) or occlusion of one or more of the following arteries: the aorta, the common iliac arteries, or the internal iliac arteries. The arteriography was compared with the resting tcPo2 values (REST) and with the minimal value (MIN) and maximal change from rest normalized to eventual chest changes (DROP) recorded during or after a treadmill test. REST, MIN, and DROP were, respectively, as follows in positive versus negative arteriograms (mean+/-SD; in mm Hg): 80.2+/-10.9 versus 78.6+/-11.5 (P>0.05), 55.2+/-20.0 versus 69.9+/-15.8 (P<0.001), and -31.8+/-17.6 versus -9.5+/-6.4 (P<0.0001) in PC and 78.9+/-14.0 versus 80.5+/-14.3 (P>0.05), 64.4+/-21.0 versus 75.1+/-14.6 (P<0.02), and -24.1+/-13.5 versus -8.7+/-4.8 (P<0.0001) in NPC. In PC and NPC respectively, with a cutoff point of -16 and -15 mm Hg, DROP showed, respectively, 83%/82% and 79%/86% sensitivity/specificity in the diagnosis of positive arteriograms.

CONCLUSIONS

Proximal ischemia is a frequent finding in vascular patients. TcPo2 measurement on the buttocks during exercise is a sensitive and specific indicator for lesions in the arterial tree toward the hypogastric circulation. Potentially it could objectively assess the response to endovascular or surgical approaches to iliac lesions.

Evaluation of ifenprodil efficacy on exercise-induced tissue ischemia in stage II arteriopathy by measurement of transcutaneous oxygen tension during a standard treadmill test: double-blind study of injectable ifenprodil versus placebo

Measurement of transcutaneous oxygen tension (TcPO2) is a noninvasive and easily reproducible method for objectifying and quantifying exercise ischemia in patients with stage II occlusive arterial disease. This technique is also used at rest to evaluate the therapeutic effect of vasoactive treatments. To objectively assess the effectiveness of a vasoactive treatment on the conditions of tissue perfusion, a randomized double-blind study of ifenprodil tartrate versus placebo was performed in 20 patients, whose TcPO2 was continuously measured while they walked on a treadmill. Patients treated with ifenprodil improved significantly as compared with the placebo group, for both the half-hypoxia area, representing the overall evolution of the tissue ischemia (+34.9% and -16.0%, respectively, p = 0.01), and the half-hypoxia recovery time, estimating the postexercise recovery time (+30.2% and -3.6%, respectively, p < 0.05). This study confirms that the continuous measurement of TcPO2 during the recovery phase after exercise represents an objective method for the evaluation and follow-up of patients with stage II intermittent claudication. The results enabled the objective assessment of ifenprodil efficacy on the evolution of tissue hypoxia.