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

Participation of Arterial Ischemia in Positional-Related Symptoms among Patients Referred for Thoracic Outlet Syndrome

Objectives: The coexistence of arterial compression with neurogenic thoracic outlet syndrome (TOS) is associated with a better post-surgical outcome. Forearm transcutaneous oxygen pressure (TcpO2) using the minimal decrease from rest of oxygen pressure (DROPmin) can provide an objective estimation of forearm ischemia in TOS. We hypothesized that a linear relationship exists between the prevalence of symptoms (PREVs) and DROPmin during 90° abduction external rotation (AER) provocative maneuvers. Thereafter, we aimed to estimate the proportion of TOS for which arterial participation is present. Methods: Starting in 2019, we simultaneously recorded forearm TcpO2 recordings (PF6000 Perimed®) and the presence/absence of ipsilateral symptoms during two consecutive 30 s AER maneuvers for all patients with suspected TOS. We retrospectively analyzed the relationship between the prevalence of symptoms and DROPmin results. We estimated the number of cases where ischemia likely played a role in the symptoms, assuming that the relationship should start from zero in the absence of ischemia and increase linearly to a plateau of 100% for the most severe ischemia. Results: We obtained 2560 TcpO2 results in 646 subjects (69% females). The correlation between PREVs and DROPmin was 0.443 (p < 0.001). From these results, we estimated the arterial participation in TOS symptoms to be 22.2% of our 1669 symptomatic upper limbs. Conclusions: TcpO2 appears to be an interesting tool to argue for an arterial role in symptoms in TOS. Arterial participation is frequent in TOS. Whether DROPmin could predict treatment outcomes better than the sole presence of compression is an interesting direction for the future.

Endovascular Revascularization of Isolated Internal Iliac Artery for symptomatic occlusive atherosclerotic disease is a viable and underutilized option for patients with gluteal muscle claudication

Often confused with pseudoclaudication, gluteal muscle claudication is a difficult condition to diagnose and treat. We present the case of a 67-year-old man with a history of back and buttock claudication. He had undergone lumbosacral decompression with no relief of buttock claudication. Computed tomography angiography of the abdomen and pelvis showed occlusion of the bilateral internal iliac arteries. Exercise transcutaneous oxygen pressure measurements obtained on referral to our institution revealed a significant decrease. He underwent successful recanalization and stenting of the bilateral hypogastric arteries with complete resolution of his symptoms. We also reviewed the reported data to highlight the trend in the management of patients with this condition.

Lower Extremity Arterial Disease and Lumbar Spinal Stenosis: A Study of Exercise-Induced Arterial Ischemia in 5197 Patients Complaining of Claudication

Only few studies have analyzed the associations of lower extremity artery disease (LEAD) with lumbar spinal stenosis (LSS), although it is expected to be a frequent association. With exercise-oximetry, we determined the presence of exercise-induced regional blood flow impairment (ischemia) in 5197 different patients complaining of claudication and referred for treadmill testing. We recorded height, weight, age, sex, ongoing treatments, cardiovascular risk factor (diabetes, high blood pressure, current smoking habit), and history of suspected or treated LSS and/or lower limb revascularization. An ankle-brachial index at rest < 0.90 or >1.40 on at least one side was considered indicative of the presence of LEAD (ABI+). Ischemia was defined as a minimal DROP (Limb-changes minus chest-changes from rest) value < −15 mmHg during exercise oximetry. We analyzed the clinical factors associated to the presence of exercise-induced ischemia in patients without a history of LSS, using step-by-step linear regression, and defined a score from these factors. This score was then tested in patients with a history of LSS. In 4690 patients without a history of (suspected, diagnosed, or treated) LSS, we observed that ABI+, male sex, antiplatelet treatment, BMI< 26.5 kg//m2, age ≤ 64 years old, and a history of lower limb arterial revascularization, were associated to the presence of ischemia. The value of the score derived from these factors was associated with the probability of exercise-induced ischemia in the 507 patients with a history of LSS. This score may help to suspect the presence of ischemia as a factor of walking impairment in patients with a history of lumbar spinal stenosis.

Exercise-Induced Plasma Metabolomic Profiles in Patients With Peripheral Arterial Disease

Aim: A better knowledge of the biological consequences in the blood of these exercise-induced ischemic events in lower extremity artery disease (LEAD) may improve the prospects of disease management. We explored the preminus postexercise metabolomic difference in 39 patients with LEAD referred for a treadmill oximetry test [transcutaneous oximetry (TcPO₂)].

Methods: Ischemia was estimated through the sum of decrease from rest of oxygen pressure (DROPs) (limb TcPO₂ changes minus chest TcPO₂ changes) at buttocks, thighs, and calves regions. Targeted metabolomic analyses measuring 188 metabolites were performed on a few microliters blood samples taken at the earlobe at rest and 3 min after exercise.

Results: Maximum walking distance (MWD) was 290 m (120–652 m) and ankle brachial index (ABI) was 0.67 ± 0.17. Supervised paired partial least squares discriminant analysis based on 23,345 models showed good predictive performance for test sets with a median area under the receiver operating characteristic (AUROC) curve value of 0.99 and a p-value of 0.00049. The best discriminant metabolites contributing to the model included a subset of 71 (47%) of the 150 accurately measured metabolites in the plasma, comprising 3 acylcarnitines, 3 amino acids, 5 biogenic amines, 9 sphingomyelin, 7 lysophosphatidylcholines, and 44 phosphatidylcholines. In addition, 16 of these metabolites were found to correlate with one or more severity scores of the LEAD.

Conclusion: Our results provide new insights into the biological changes that accompany exercise in LEAD and contribute to a better understanding of walking impairment pathophysiology in LEAD, highlighting new candidate biomarkers.

Kneeling-induced calf ischemia: a pilot study in apparently healthy European young subjects

PURPOSE

Many tasks, sports or leisure activities require maximal knee flexion. We hypothesized that this position could result in reduced calf perfusion, in young European subjects.

METHODS

We quantified calf ischemia resulting from the knee flexion with transcutaneous oxygen pressure (TcpO2) sensors by assessing the decrease from rest of TcpO2 (DROP) defined as limb changes minus chest changes. A minimal DROP (DROPm) <-15 mmHg defines the presence of ischemia. From the crawling position, participants kneeled for 3 min while bending as in prostration/prayer position (P). Thirty-five participants repeated this maneuver a second time, while 7 participants were also required to sit on their heels with the torso in the vertical position to attain knee flexion without significant groin flexion (S).

RESULT

In 41 healthy young volunteers (30 males), 25 [20-31] years old, 37 patients showed a DROPm < -15 mmHg from "R" to "P" in one (n = 4) or both (n = 33) calves (90.2%; 95% CI 76.9-97.3). After backward regression of the DROPm, there was no significant association with side, body weight of systolic blood pressure. However, age was strongly associated with DROPm (OR 5.34 [2.45-8.69]) so that DROPm was significantly higher in older, with a correlation ρ = 0.31 (p = 0.003).

CONCLUSION

Kneeling dramatically reduces calf perfusion, likely through popliteal artery kinking, possibly through muscle crushing. Eastern lifestyle includes routine flexed position since childhood. Whether or not such a chronic training reduces the risk of kneeling-induced ischemia in adults is unknown to date.