Pain description in patients with isolated proximal (without distal) exercise-related lower limb arterial ischemia

Investigation of arterial claudication with transcutaneous oxygen pressure at exercise: Interests and limits

Transcutaneous oxygen pressure (TcpO2) measurement has been used for years at rest in patients with lower extremity artery disease. It was proposed for exercise testing (Ex-TcpO2) in the 80ies to evaluate regional blood flow impairment (RBFI) at the proximal and distal levels simultaneously and on both sides, in case of claudication. It was suggested that the use of a chest electrode was mandatory to show that decreases in TcpO2 at the limb level result from limb RBFI and not from a systemic pO2 decrease of cardiopulmonary origin (exercise-induced hypoxemia). Unfortunately, a major pitfall of Ex-TcpO2 was the low absolute reliability of the regional perfusion index (RPI: ratio of limb to chest values) and the technique was almost abandoned until 2003, when the DROP index (Decrease from rest of oxygen pressure: limb changes minus chest changes from rest) was proposed. The DROP mathematical formula makes Tcpo2 results independent from the absolute pO₂ starting values, improving reliability of Ex-TcpO2 as compared to the RPI. Since then, Ex-TcpO2 has been of renewed interest. The present paper addresses the physiology of Ex-TcpO2, interpretation of its results, and common misunderstandings about its use.

High prevalence of exercise-induced ischemia in the asymptomatic limb of patients with apparently strictly unilateral symptoms and unilateral peripheral artery disease

BACKGROUND:

The prevalence of exercise-induced ischemia in the asymptomatic limb of patients with unilateral claudication based on history and treadmill evaluation, and with unilateral ipsilateral peripheral artery disease (i.e ankle-to-brachial systolic pressure index <0.90) is unknown.

METHODS:

We detected exercise-induced ischemia in the asymptomatic limb of patients with apparently unilateral claudication. Among 6059 exercise-oximetry tests performed in 3407 nondiabetic and 961 diabetic patients. We estimated the intensity of ischemia in the both limb (buttocks and calves) using the lowest minimum value of the decrease from rest of oxygen pressure (DROP; limb changes minus chest changes from rest), with significant ischemia defined as DROP lower than -15 mmHg.

RESULTS:

We found 152 tests performed in 142 nondiabetic patients and 40 tests performed in 38 diabetic patients. The asymptomatic limb showed significant ischemia in 46.7% and 37.5% of the tests. Strictly unilateral exercise-induced claudication with apparently unilateral peripheral artery disease was rare (<4% of all tests). However, among these highly selected tests, significant ischemia was found in the asymptomatic limb in more than one-third of cases.

CONCLUSION:

The asymptomatic limb of patients with peripheral artery disease should not be considered a normal limb.

Clinical application of transcutaneous oxygen pressure measurements during exercise

Exertional lower limb pain is a frequent diagnostic issue in elderly patients. Arterial claudication results from the mismatch between the oxygen requirement of, and oxygen delivery to the exercising muscles. Non-invasive vascular investigations (ultrasound imaging, plethysmography or segmental pressure) are used in routine at rest or following exercise, but none can be used during walking or to directly monitor cutaneous oxygen delivery to the limb. Here, we review the methods, tips and traps of the transcutaneous oxygen pressure measurement technique and potential applications. Transcutaneous oxygen pressure measurement is largely used in vascular medicine for patients with critical limb ischemia. It can also detect regional blood flow impairment at the proximal and distal limb simultaneously and bilaterally during exercise. Exercise-oximetry can also analyze systemic oxygen pressure changes on a reference area on the chest, to screen for occult pulmonary disease. As a surface technique, it does not directly measure muscle oxygen content but provides a reliable estimation of regional blood flow impairment. With the use of a recently reported index that is independent of the unknown transcutaneous gradient for oxygen, exercise-oximetry provides some accurate information compared to classical non-invasive vascular investigations to argue for a vascular or non-vascular origin of exertional lower limb pain during exercise. Although a time consuming technique, it is a simple test and it is progressively spreading among referral vascular centers as a useful non-invasive diagnostic tool for patients suspected of arterial claudication.

Exercise transcutaneous oximetry significantly modifies the diagnostic hypotheses and impacts scheduled investigations or treatments of patients with exertional limb pain

INTRODUCTION

In lower extremity peripheral artery disease (PAD), transcutaneous oximetry at exercise (Ex-TcpO2) has been largely validated in research practice, but evidence of routine practice in various vascular laboratories is missing. We hypothesized that Ex-TcPO2 would change the diagnosis hypotheses, investigations and treatments for patients referred for exertional limb pain.

MATERIAL & METHODS

A multicenter prospective trial was conducted in nine different referral centers. Investigators performed Ex-TcpO2 and recorded investigations and treatments already scheduled for the patient. We encoded referral physician's diagnostic hypothesis. Before Ex-TcpO2, vascular physicians were asked to give their diagnosis hypotheses. A minimal decrease from rest of oxygen pressure (DROP)<minus 15mmHg defined the presence of exercise-induced ischemia on the area of interest. After Ex-TcPO2, we recorded post-test diagnostic hypothesis and investigations and treatments to be cancelled or performed. We compared the diagnosis hypotheses, scheduled investigations and treatments, before and after the Ex-TcpO2.

RESULTS

We included 603 patients (485 males: 80.4%), aged 64.7±9.8years. The post-test diagnosis hypothesis differed in 266 patients (44.1%; p<0.0001) and in 96 patients (15.9%) from the pre-test hypothesis of referring and vascular physician, respectively. This led to the recommendation to cancel 27 scheduled investigations or treatments of a total cost of ~130,000 euros.

DISCUSSION

Ex-TcPO2 in patients with exertional limb pain is applicable in various vascular institutions, and significantly modifies the diagnostic hypotheses and impacts scheduled investigations or treatments of patients with exertional limb pain.

Simultaneous pain intensity rating and quantification of ischemia throughout exercise and recovery in proximal versus distal arterial claudication

Data on simultaneous hemodynamic changes and pain rating estimation in arterial claudication while walking are lacking. This study was conducted to determine if a difference in transcutaneous oxygen pressure (tc pO2) exists between proximal and distal localization at pain appearance (PAINapp), maximal pain (PAINmax) and pain relief (PAINrel) in proximal or distal claudication and if a relationship exists between tc pO2 changes and pain intensity. We analyzed the pain rating (Visual Analog Scale (VAS)) to lower limb ischemia, measured with the decrease from rest of oxygen pressure (DROP) tc pO2 index during constant-load treadmill tests in patients with calf ( n = 41) or buttock ( n = 19) claudication. Calves versus buttocks results were analyzed with ANOVA tests. The R2 correlation coefficient between individual VAS versus DROP was calculated. Ischemia intensity versus pain rating changes were correlated. Significant ischemia was required for pain appearance, but pain disappeared despite the persistence of ischemia. We observed no statistical difference for DROP at PAINapp, PAINmax or PAINrel between proximal or distal claudication. A significant correlation between pain rating versus DROP was found: from PAINapp to PAINmax, R2 = 0.750 (calves) and 0.829 (buttocks), and from PAINmax to PAINrel, R2 = 0.608 (calves) and 0.560 (buttocks); p<0.05. Pain appeared after a significant decrease of hemodynamic parameters but disappeared while parameters were not normalized. No difference in pain rating was found in proximal versus distal claudication.

Internal Iliac Artery Stenosis: Diagnosis and How to Manage it in 2015

Lower extremity arterial disease (LEAD) is a highly prevalent disease affecting 202 million people worldwide. Internal iliac artery stenosis (IIAS) is one of the localization of LEAD. This diagnosis is often neglected when a patient has a proximal walking pain since most physicians evoke a pseudoclaudication. Surprisingly, IIAS management is reported neither in the Trans-Atlantic Inter-Society Consensus II nor in the report of the American College Foundation/American Heart Association guidelines. The aims of this review are to present the current knowledge about the disease, how should it be managed in 2015 and what are the future research trends.

Application of exercise transcutaneous oxygen pressure measurements for detection of proximal lower extremity arterial disease: a case report

Proximal claudication is secondary to ischemia caused by peripheral artery disease (PAD), whereas proximal pseudo-claudication is secondary to other disease processes such as hip arthritis, spinal stenosis, neuropathy, and so forth. The differentiation between the two can be challenging. Exercise transcutaneous oxygen pressure measurement (exercise-TcPO2) allows noninvasive detection of flow-reducing lesions in the proximal arteries and tributaries of the lower extremity arterial tree. We present the first case report in the United States using an exercise-TcPO2 algorithm. A 71-year-old diabetic patient with proximal left-sided and right-calf claudication with indeterminate ankle-brachial indices underwent an exercise-TcPO2 study before and after endovascular intervention. Four TcPO2 probes were placed: one at chest level (reference probe), one on each buttock, and one on the symptomatic calf. The Delta from Resting Oxygen Pressure (DROP) index was calculated at each probe site using a previously validated protocol. Proximal left- and right-calf ischemia were confirmed by the initial exercise-TcPO2, and, after endovascular treatment of the left iliac artery lesion, improvements in proximal exercise-TcPO2 values were found. These data suggest that exercise-TcPO2 can be useful in PAD evaluation in patients with non-compressible arteries and/or proximal claudication.

Impaired somatosensation in patients with isolated proximal-without-distal exercise-related lower-limb ischemia

OBJECTIVES

Isolated proximal-without-distal (buttock but not calf) exercise-related lower-limb ischemia (IPI) might develop in the presence of arterial lesions impairing the blood flow supply toward the hypogastric vascular bed. In IPI, lower-limb sensory nerve dysfunction might occur from the sacral nerve plexus becoming ischemic during exercise. The purpose of this study was to compare patients with IPI with healthy controls for the presence of sensory nerve dysfunction, as assessed using somatosensory testing (SST).

METHODS

Seventeen nondiabetic patients with IPI and 17 age-matched and sex-matched healthy controls underwent SST of both the upper and lower limbs.

RESULTS

The upper-limb SST data did not differ between groups (P>0.05). In contrast, lower-limb testing showed that patients with IPI had impaired warm (43.4±2.7 vs. 40.5±4.9°C) and vibration (5.0±2.3 vs. 6.4±1.4 arbitrary units) detection thresholds compared with healthy controls (P≤0.05). Furthermore, lower-limb mechanical detection threshold and Neuropathy Symptom and Disability Scores tended to be higher in the patients (P≤0.10).

DISCUSSION

The SST data suggest that patients with IPI have abnormal functioning of Aβ-fiber and C-fiber inputs in their affected limb(s). These sensory abnormalities might contribute to the exercise-induced ischemic symptoms experienced by these patients.

Heart rate recovery after constant-load exercise tests is decreased in proportion to the importance (severity and diffusion) of exercise-induced lower-limb ischaemia

BACKGROUND

Conditions that may influence heart rate recovery at 1 min of recovery from exercise (HRR1: end-exercise heart rate minus heart rate 1 min after exercise) are not fully understood. We hypothesized that the 'importance' (both local severity and regional diffusion) of peripheral skeletal muscle ischaemia is associated with low HRR1.

DESIGN AND METHODS

In 529 patients with suspected or confirmed peripheral vascular disease not receiving beta-blockers (61·4 ± 11·3 years old), we retrospectively studied the relationship of HRR1 to exercise-induced changes in transcutaneous oxygen DROP index (limb changes minus chest changes from rest). The sum of DROP indices observed on both calves and both buttocks (DROPtot) provides the unique opportunity to estimate both the severity and the diffusion of exercise-induced ischaemia on the right and left side simultaneously. It was used during a constant-load treadmill test (3·2 km h(-1) ; 10% grade) to classify patients in quartiles, the fourth quartile representing the more 'important' ischaemias.

RESULTS

There was an inverse relationship between quartiles of DROPtot and HRR1, even after adjustment for heart rate reserve (Delta HR: end-exercise minus resting heart rate), age (≤ or >60 years), gender, body mass index, treadmill maximal walking distance and ankle brachial index: adjusted R = 0·629; P<0·0001.

CONCLUSIONS

During constant-load treadmill testing, DROPtot, an index of the 'importance' of exercise-induced lower-limb ischaemia, correlates with HRR1. Whether HRR1 is improved in proportion of DROPtot improvement in patients undergoing surgery or rehabilitation for peripheral artery disease is a fascinating issue for future studies.

Endovascular Treatment of the Internal Iliac Artery in Peripheral Arterial Disease

In patients with peripheral arterial disease not much is known about the relationship between the localization of the pain and the localization of arterial occlusions in the iliac arteries. Occlusions high in the iliac arteries are assumed to be able to induce pain in the buttocks and upper leg as well as pain in the calves. Several case reports show that the symptoms of arteriosclerotic lesions in the internal iliac artery are often atypical and not easy to diagnose. In this report, 3 patients with internal iliac artery occlusions who were treated with percutaneous transluminal angioplasty (PTA) are described. One patient had isolated pain in the buttock region. In the other 2 patients the initial pain was focused on the buttock region with extension to the calves during exercise. After PTA, 2 patients were free of symptoms, while in the other patient the symptoms improved but did not disappear. Future research should clarify the relation between certain arterial occlusions and the location of the pain.

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.

Douleurs ambiguës “de hanche” ou de fesse, artérite proximale ou canal lombaire sténosé?

Proximal arterial stenosis (bifurcation of the aortic, common iliac and especially hypogastric or hip arteries) can cause misleading 'hip' or buttock pain (two thirds of these cases involve the area of the trochanter, groin, or thigh). Their essential characteristic is that they cause patients to stop walking, improve in a minute or two and reappear when the patient starts walking again. Neither articular complications nor periarthritis of the hip fit this pattern, and physical examination and imaging exclude them. Neurogenic intermittent claudication is more difficult to rule out: it is 'often accompanied by paresthesia and anteflexion of the trunk to relieve the pain. A radiologic image of lumbar canal stenosis alone does not indicate that it is responsible for the pain: the stenosis may be asymptomatic and only fortuitously associated with the pain. The usual reduction in femoral pulse or ankle pressure index is absent if the stenosis is located on the hypogastric or gluteal artery and there is not substantial damage to the aorta-iliac axis. Arterial stenosis is confirmed by Doppler ultrasound. Arteriography is an examination performed during treatment, to guide angioplasty. It is indicated when medical treatment fails, as it frequently does.

Crossed retroperitoneal approach to the internal iliac artery: a preliminary anatomical study

The internal iliac arteries (IIA), and especially the distal segment, course very deep in the pelvis and are generally difficult to access surgically. The recent development of simple and reliable methods to investigate proximal ischemia of the lower extremities has led to discovery of more candidates for elective revascularization of the IAA. The classic approaches to the IAA, i.e., the transperitoneal and homolateral retroperitoneal routs have certain disadvantages. We present a new crossed retroperitoneal approach to the IAA and the results of such method in six cadavers. In all six cases, the entire IAA could be exposed without any particular problems. This novel approach to the IAA seems to be both simple and reproducible.