Vascular elastography: a novel method to characterize occluded lower limb arteries prior to endovascular therapy

Elastographic Assessment of Atherosclerotic Plaques and Determination of Vascular Risk in Patients with Rheumatoid Arthritis

Objectives: The present study aimed to examine the role of two-dimensional shear wave elastography (SWE) in the assessment of the vascular wall of the carotid arteries and atherosclerotic plaques in patients with rheumatoid arthritis with moderate and low disease activity versus healthy controls. Methods: An observational case-control study was carried out at the University Medical Hospital "Kaspela" in Plovdiv, Bulgaria, from June 2023 to August 2024. This study included 24 patients with rheumatoid arthritis (RA) and 25 healthy controls. We employed two-dimensional SWE (2D-SWE) to examine the vessels around the plaques. The potential links with the degree of stenosis, plaque type, and cardiovascular risk were analyzed. Results: In the RA group, the 2D-SWE values showed significant positive correlations with the severity of the atherosclerotic plaques (rs = 0.461; 95% CI: 0.049 to 0.739; p = 0.023) and the degree of stenosis (rs = 0.920; 95% CI: 0.793 to 0.970; p < 0.001). Based on 2D-SWE, a ROC curve analysis distinguished higher severity plaques from lower severity plaques with an AUC = 0.818, 95% CI: 0.683 to 0.913. The optimal cut-off value of 2D-SWE > 32.40 kPa was associated with a sensitivity of 96%, a specificity of 56%, a positive predictive value (PPV) of 66.70%, and a negative predictive value (NPV) of 92.90%. Conclusion: Elastography can be an effective technique for assessing and stratifying atherosclerotic plaques in patients with RA, as well as for aiding in the early detection and subsequent prevention of future complications.

Utility of Dual-Energy Computed Tomography in lesion characterization and treatment planning for peripheral Chronic Total Occlusions: A comprehensive analysis of crossing difficulty

PURPOSE

To investigate whether Dual-Energy Computed Tomography (DECT) could be useful in the lesion characterization and endovascular treatment planning of symptomatic patients with peripheral arterial disease (PAD) due to Chronic Total Occlusions (CTO).

MATERIALS AND METHODS

Between 2018 and 2022, 60 symptomatic patients (52 male, age 71 years) with peripheral arterial CTO underwent DECT angiography before percutaneous endovascular treatment. Patients were classified, according to guidewire crossing difficulty into four categories, which were subsequently correlated with DECT values, including Dual Energy Index (DEI) and Effective Z (Zeff). DECT values were also corelated with crossing time. The crossing difficulty was further correlated with the Trans-Atlantic Inter-Society Consensus Document (TASC II) classification.

RESULTS

Technical success, defined as perceived antegrade true lumen or subintimal crossing, was achieved in 76.7 %. Among the cases, 20 were deemed easy, 14 moderate, 12 hard and 14 were failed attempts. Statistical analysis revealed a significant correlation between DEI, Zeff values, and the crossing difficulty categories (p < 0.001). Additionally, there was also a correlation between crossing time and DECT values. However, no significant correlation was recorded between difficulty categories and TASC II classification.

CONCLUSION

Pre-procedural DECT angiography provides valuable information for patient selection and planning of the revascularization strategy. Moreover, it is helpful in the selection of the appropriate PTA materials, based on the lesion characteristics. Further research should be invested in this important field, to determine the optimal treatment approach in patients suffering from PAD due to CTOs.

Cardiac thrombotic stability determined by contrast-enhanced echocardiography: investigative protocol and preliminary results

Objective

This study’s intent was to test a new system for scoring cardiac thrombotic stability, based on contrast-enhanced ultrasound (CEUS).

Methods

We used human whole blood for an in vitro thrombotic model involving 1-h (T_1h) and 7-day (T_7d) subsets. The T_1h group was monitored for 1 h continuously to observe for the formation of a new thrombus on the original thrombus base. Changes in thrombotic CEUS images, histologic features, and shear wave elastography were recorded over time. We also studied 28 patients diagnosed with cardiac thrombi, each examined by transthoracic echocardiography and CEUS.Thrombi were scored for substrate (T_s) and hardness (T_h) based on the visualized degree of contrast penetration into the thrombi. Statistical analyses of T_s and T_h reflected thrombolytic time and risk of embolism to other organs.

Results

Histologically, the loosely constructed ends of in vitro thrombi solidified over time. In addition, the average Young’s modulus of thrombi over time indicated a progressive increase in hardness. Contrast-enhancing agents were able to penetrate fresh, loose thrombi only, not chronic, stable thrombi. As T_s and T_h increased, prolonged thrombolytic time and greater risk of embolism to other organs were apparent.

Conclusions

Our data suggest that this new CEUS scoring system correlates well with cardiac thrombotic hardness and the quality of its underlying substrate, serving to quantify thrombotic stability.

Ultrasound Methods in the Evaluation of Atherosclerosis: From Pathophysiology to Clinic

Atherosclerosis is a key pathological process that causes a plethora of pathologies, including coronary artery disease, peripheral artery disease, and ischemic stroke. The silent progression of the atherosclerotic disease prompts for new surveillance tools that can visualize, characterize, and provide a risk evaluation of the atherosclerotic plaque. Conventional ultrasound methods-bright (B)-mode US plus Doppler mode-provide a rapid, cost-efficient way to visualize an established plaque and give a rapid risk stratification of the patient through the Gray-Weale standardization-echolucent plaques with ≥50% stenosis have a significantly greater risk of ipsilateral stroke. Although rather disputed, the measurement of carotid intima-media thickness (C-IMT) may prove useful in identifying subclinical atherosclerosis. In addition, contrast-enhanced ultrasonography (CEUS) allows for a better image resolution and the visualization and quantification of plaque neovascularization, which has been correlated with future cardiovascular events. Newly emerging elastography techniques such as strain elastography and shear-wave elastography add a new dimension to this evaluation-the biomechanics of the arterial wall, which is altered in atherosclerosis. The invasive counterpart, intravascular ultrasound (IVUS), enables an individualized assessment of the anti-atherosclerotic therapies, as well as a direct risk assessment of these lesions through virtual histology IVUS.

Thrombotic Lesions are Associated with Poor Outcomes after Endovascular Treatment in Patients with Non-Acute Aortoiliac Total Occlusions

Aim: The post-endovascular treatment outcomes of thrombotic lesions remain unclear. This study aimed to investigate the effects of thrombotic lesions on post-endovascular treatment outcomes in patients with non-acute aortoiliac total occlusions.

Methods: This subanalysis of a multicenter prospective observational registry study included patients from 64 institutions in Japan between April 2014 and April 2016. A total of 346 patients (394 limbs; median age, 72 years), including 186 men, underwent endovascular treatment for non-acute aortoiliac total occlusions and were included. The patients were classified as having thrombotic or non-thrombotic lesions. The primary (1-year primary patency rate) and secondary (1-year overall survival rate) endpoints were evaluated.

Results: Thrombotic lesions were identified in 18.5% (64/346) of the patients. The 1-year primary patency (85.9% versus 95.4%, log-rank p ＜.001) and overall survival (90.6% versus 97.9%, log-rank p =.003) rates were significantly lower in the thrombotic group than in the non-thrombotic group. Thrombotic lesions had significant effects on the post-endovascular treatment outcomes, with adjusted hazard ratios of 3.91 (95% confidence interval, 1.64–9.34, p =.002) for primary patency and 4.93 (95% confidence interval, 1.59–15.3, p =.006) for all-cause mortality.

Conclusions: Thrombotic lesions were associated with 1-year restenosis and all-cause mortality after endovascular treatment for non-acute aortoiliac total occlusions. Endovascular treatment strategies should be carefully planned for patients with thrombotic lesions.

Identification of micro-channels within chronic total occlusions using contrast-enhanced ultrasound

BACKGROUND

Vascular micro-channels within chronic total occlusions (CTO) have been identified in histopathology and animal studies. They have been proposed as a potential path for achieving endovascular crossing via the lumen. There are currently no noninvasive means of imaging these structures. The aim of this study was to investigate whether contrast-enhanced ultrasound (CEUS) examination can identify micro-channels within CTO in humans.

METHODS

CTO within the femoropopliteal arteries were imaged with CEUS examination in 38 patients. Segments containing micro-channels were identified and their length measured. The proportion of occlusion length containing micro-channels was assessed for each case. Micro-channel appearances including linear or tortuous configuration, crossing of occlusion caps, and connections to vasa vasorum were recorded.

RESULTS

The median CTO length was 17.0 cm (interquartile range [IQR], 6.9-27.9 cm) and median age of CTO was 12 months (IQR, 6-16 months). Micro-channels were identified in 92.1% of cases (35/38). The median length within a lesion containing micro-channels was 6.4 cm (IQR, 2.4-14.3 cm) and median proportion of CTO containing micro-channels was 47.9% (IQR, 1.7%-28.5%). A linear micro-channel configuration was seen in 84.2% of cases and a tortuous configuration was seen in 57.9% of cases. Micro-channel connections through the cap were seen in 50% (19/38 cases) and connections to the vasa vasorum in 71.1% (27/38 cases). No association was found between the proportion of each lesion containing micro-channels and CTO age, lesion length or calcification severity. There were no adverse effects related to contrast use.

CONCLUSIONS

CEUS can be used to detect micro-channels in CTO in human femoropopliteal arteries. This imaging technique is safe and minimally invasive and may represent a practical method for selection of occlusion crossing method. Further work is required to determine whether identification of micro-channels can be used to improve treatment decision-making and provide a better understanding of the natural history of femoropopliteal CTO.

Influence of Vertebrobasilar Stenotic Lesion Rigidity on the Outcome of Angioplasty and Stenting

Stenotic lesion rigidity (SLR) has an unclear influence on the outcome of percutaneous transluminal angioplasty and stenting (PTAS) for intracranial arterial stenosis. This study evaluated the outcome of PTAS and the relationship of vertebrobasilar SLR to features on vessel wall MRI (VW-MRI) for identifying pathologies of vertebrobasilar stenosis (VBS) and evaluating PTAS outcome. We retrospectively evaluated the results of PTAS in 31 patients with severe VBS. Stenotic lesions were classified as soft (based on predilatation pressure [PP] ≦ 4 atm) in 15 patients or hard (PP >4 atm) in 16 patients. We examined the relationship of SLR to clinical and MR findings. Patients with hard vs soft lesions had atherosclerosis (8/16 [50.0%] vs 2/15 [13.3%]), dissection (0/16 [0.0%] vs 12/15 [80.0%]), and dissection in atherosclerosis (8/16 [50.0%] vs 1/15 [6.7%], P < 0.0001); high intensity signal on the T1WI of VW-MRI (5/16 [31.3%] vs 14/15 [93.3%]) and iso- to low intensity signal (11/16 [68.7%] vs 1/15 [6.7], P = 0.001), and significant in-stent restenosis (>50%) in 5/15 (33.3%) vs 0/15 (0.0%) (P = 0.0421) in the 30 patients who successfully completed PTAS. Vertebrobasilar SLR correlated well with lesion etiology, findings on VW-MRI, and PTAS outcome. Patients with hard stenotic lesions need close follow-up after PTAS.

Cooper K, Majdalany BS, Kalva SP, Chandra A, Collins JD, Francois CJ, Ganguli S, Gornik HL, Kendi AT, Khaja MS, Minocha J, Norton PT, Obara P, Reis SP, Sutphin PD, Rybicki FJ. ACR Appropriateness Criteria® Lower Extremity Arterial Revascularization-Post-Therapy Imaging

Peripheral arterial disease (PAD) affects millions across the world and in the United States between 9% to 23% of all patients older than 55 years. The refinement of surgical techniques and evolution of endovascular approaches have improved the success rates of revascularization in patients afflicted by lower extremity PAD. However, restenosis or occlusion of previously treated vessels remains a pervasive issue in the postoperative setting. A variety of different imaging options are available to evaluate patients and are reviewed within the context of asymptomatic and symptomatic patients with PAD who have previously undergone endovascular or surgical revascularization. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Ultrasound Vascular Elastography as a Tool for Assessing Atherosclerotic Plaques - A Systematic Literature Review

Atherosclerosis is a widespread disease that accounts for nearly 3-quarters of deaths due to cardiovascular disease. Ultrasound elastography might be able to reliably identify characteristics associated with vulnerable plaques. There is a need for the evaluation of elastography and its ability to distinguish between vulnerable and stable plaques. The aim of this paper is to provide an overview of the literature on vascular elastography. A systematic search of the available literature for studies using elastography for assessing atherosclerotic plaques was conducted using the MEDLINE, Embase, Cochrane Library and Web of Science databases. A standardized template was used to extract relevant data following the PRISMA 2009 checklist. 20 articles were included in this paper. The studies were heterogeneous. All studies reported that elastography was a feasible technique and provided additional information compared to B-mode ultrasound alone. Most studies reported higher strain values for vulnerable plaques. Ultrasound elastography has potential as a clinical tool in the assessment of atherosclerotic plaques. Elastography is able to distinguish between different plaque types, but there is considerable methodological variation between studies. There is a need for larger studies in a clinical setting to determine the full potential of elastography.