The Role of the Deep Femoral Artery in the Treatment of Thigh Claudication in Case of Hypogastric Occlusion

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.