Weakness of lower limb muscle in symptomatic peripheral artery disease with media sclerosis detected by ultrasound shear wave elastography.

Background: Symptomatic peripheral arterial disease (PAD) is difficult to non-invasively diagnose in the presence of calcified, media sclerotic arteries that are incompressible by blood pressure cuffs. Standard ankle-brachial index (ABI) measurements in these PAD patients are very often not helpful. Shear wave elastography (SWE) is a modern ultrasound technique to detect peripheral muscle stiffness changes i.e. muscle weakness during exercise. In a pilot study, we examined whether SWE could be a reproducible tool for diagnosing ischemic loss of muscle stiffness in patients with PAD and concomitant arterial media sclerosis. Patients and methods: N=13 consecutive patients with peripheral artery disease and media sclerosis were enrolled in the pilot study. All 13 patients were symptomatic in different stages of their PAD due to hemodynamically relevant arterial stenosis or occlusions of limb arteries as confirmed by oscillography, color-coded duplex sonography or angiography. Results: ABI measurements were invalid in all 13 patients. Mean SWE measurements of medial gastrocnemius muscles showed a significant transient muscle stiffness loss (weakness) at maximum exercise (active dorsal flexion of the foot, 103.4±25.9 kPa on the asymptomatic vs. 62.5±21.9 kPa on the symptomatic limb (p<0.001). Conclusions: SWE can reproducibly detect peripheral muscle weakness during exercise in the symptomatic leg of media sclerotic PAD patients. SWE of lower limb muscles may help to identify symptomatic PAD in patients presenting with invalid ABI measurements and unclear vascular status.

Successful Secondary Endovascular Intervention in Pediatric Patients with Venous Thromboembolic Events.

BACKGROUND: In the past, pediatric patients with venous thromboembolic events (VTE) were treated with low-molecular-weight heparin (LMWH) which was successful in around 70% of the cases. However, anticoagulation alone might not restore patency in all patients, and advanced therapeutic options to prevent postthrombotic syndrome are needed. During recent years, endovascular interventions have become a treatment option for pediatric patients with persistent thrombotic occlusion, not only in life- or limb-threatening VTE. METHODS: We evaluated 12 consecutive patients (11-17 years) with newly diagnosed VTE being treated at our department during the last 4 years (2017-2020). In case follow-up examination showed persistent venoocclusion under anticoagulation, patients received secondary interventional therapy like recanalization, percutaneous transluminal angioplasty with or without catheter-directed thrombolysis, and stenting. Patients with no clinical signs of venoocclusion or regredient thrombosis in imaging examination received anticoagulation alone. RESULTS: Six of 12 (50%) patients underwent catheter intervention. Median time from diagnosis to intervention was 4 months (0-12 months). Reintervention was necessary in one (8%) case and complete recanalization failed in one (8%) case. There were no major bleeding events or other major postinterventional complications, no acute or late local recurrence, and all patients reported clinical improvement after the procedure. CONCLUSION: If endovascular intervention is used in teenage patients with persistent symptomatic VTE, reduction of postthrombotic symptoms is possible, even if intervention is performed secondary to failure of anticoagulation. Multidisciplinary treatment decisions can be based on the clinical course and follow-up imaging.

Success of arterial revascularization determined by contrast ultrasound muscle perfusion imaging.

BACKGROUND: In the early postoperative evaluation of the success of arterial revascularization, ankle-brachial index (ABI) and other noninvasive tests lack reliability, especially in patients with incompressible arteries or local edema. Contrast-enhanced ultrasound (CEUS) imaging of limb muscle perfusion may be an alternative to standard tests if it detects treatment success reliably. METHODS: We compared a simplified CEUS method with clinical staging, pulse volume recording (PVR), and ABI in patients with lifestyle-limiting peripheral arterial disease undergoing revascularization by percutaneous transluminal angioplasty (PTA) or bypass surgery. Patients underwent staging, PVR, ABI, and CEUS before, directly after, and 3 to 5 months after successful PTA (n = 20) or successful bypass grafting (n = 14). For CEUS, contrast agent was injected into an antecubital vein, and the time from beginning to peak intensity of contrast enhancement (TTP) in the calf muscle was measured. RESULTS: Successful revascularization by both PTA and bypass was associated with a significant improvement in staging, PVR, ABI, and TTP directly after intervention and at follow-up. Median ABI increased from 0.60 to 0.85 (P = .001) after PTA and from 0.36 to 0.76 (P = .003) after bypass surgery. Median TTP decreased from 45 seconds to 24 seconds (P = .015) and from 30 seconds to 27 seconds (P = .041), respectively. McNemar analysis revealed unidirectional changes in both ABI and TTP (P = .625 after PTA and P = 1.000 after bypass surgery), and equivalence analysis showed 95% confidence intervals within clinical indifference, indicating that TTP was equivalent to standard tests in detecting successful revascularization. CONCLUSIONS: Contrast ultrasound perfusion imaging of calf muscle after arterial revascularization may be a valuable alternative to standard noninvasive tests such as ABI or PVR to determine the success of an arterial revascularization.

Simplified contrast ultrasound accurately reveals muscle perfusion deficits and reflects collateralization in PAD.

BACKGROUND: Simplified contrast-enhanced ultrasound (CEUS) can be used to evaluate muscle perfusion in peripheral arterial disease (PAD). Here, we report its diagnostic accuracy for detecting symptomatic PAD. Additionally, we hypothesize that the extent of collateral formation is reflected by CEUS. METHODS: Ultrasound contrast agent was injected into an antecubital vein of 58 control subjects and 52 symptomatic PAD patients and its appearance in the calf muscle was evaluated. Interreader variability was tested using 118 raw data films. Arterial collateralization of PAD patients was assessed by angiographic imaging. RESULTS: PAD patients showed a significantly longer median time to peak intensity (TTP, 36.9s) than control subjects (19.4s, p<0.001) with longer TTPs in advanced PAD stages. The area under the receiver operating characteristic curve was 0.942 and the mean TTP difference between two blinded readers was 0.28s. A TTP cut off at 30.5s was associated with 91% positive predictive value. PAD patients with good collateralization showed a significantly shorter TTP (34.1s) than patients with poor collateralization (44.0 s, p=0.008) but not a higher ankle-brachial index (ABI). CONCLUSIONS: CEUS accurately displays perfusion deficits of the calf muscle in symptomatic PAD patients. The degree of arterial collateralization is reflected by CEUS and not by ABI.

Contrast ultrasound perfusion imaging of lower extremities in peripheral arterial disease: a novel diagnostic method.

AIMS: The purpose of this study was to establish contrast-enhanced ultrasound perfusion imaging (CUPI) of the lower extremities as a novel non-invasive diagnostic tool for patients with peripheral arterial disease (PAD). METHODS AND RESULTS: Ultrasound contrast agent (SonoVue) was injected into a peripheral vein of 16 control subjects and 16 PAD patients and its appearance in the calf muscle was detected by low-energy harmonic ultrasound. Analysis of the wash-in curves revealed that PAD patients had a significantly longer time to peak intensity (TTP), i.e. duration of maximum contrast perfusion [37 s (19-79 s) in control subjects vs. 56 s (32-104 s) in PAD patients at rest, age-adjusted P=0.002]. Exercise stress test of the calf muscle resulted in a decrease of the TTP, maintaining the significant difference in TTP between the groups [19 s (8-37 s) in control subjects vs. 32 s (18-48 s) in PAD patients after exercise, age-adjusted P=0.004]. Neither ankle-brachial index and TTP nor age and TTP showed a significant correlation. CONCLUSION: CUPI reflects the regional blood circulation of the calf muscle. In this pilot study, PAD patients show a significantly longer TTP than control subjects. The clinical relevance of CUPI is topic of ongoing studies.