Preoperative assessment of computerized tomography angiography to predict success for crossing long Trans-Atlantic Inter-Society Consensus D lesions using the optical coherence tomography catheter

Intraluminal crossing of infrainguinal SFA chronic total occlusions may offer patency superiority compared to subintimal crossing

OBJECTIVES

Patency for chronic total occlusions (CTO) of the superficial femoral artery (SFA) after endovascular interventions traditionally demonstrate a low 1-year patency ranging from 40%-60%. The optical coherence tomography (OCT) catheter (Avinger Inc., Redwood City, CA) uses light-based technology imaging to cross Trans-Atlantic Inter-Society Consensus D (TASC D) lesions intraluminally with direct intra-arterial visualization. Insufficient data exist evaluating intraluminal crossing with OCT imaging compared with traditional subintimal techniques. We evaluated outcomes for TASC D lesions crossed intraluminally.

METHODS

A retrospective analysis of patients with SFA TASC D lesions crossed intra-arterially with the OCT catheter imaging. Descriptive statistics evaluated patient characteristics which included patient demographics, Rutherford scores, ABIs, CTA information, lesion categorization, as well as runoff score. Patency at baseline, 30-day, 6-month, and 1-year outcomes were compared using t-tests. Cumulative patency rates were evaluated using Kaplan-Meier analysis.

RESULTS

101 patients underwent elective intervention for SFA TASC D lesions with the OCT catheter. The crossing rate was 78.2%, mean lesion length was 16.2 cm, and runoff at the tibial level was 2.2 patent vessels. Mean age and BMI were 64 years and 29 kg/m2, respectively. Patient characteristics are male (57%); Caucasian (90%); ever smoking (85%); hypertension (82%), hyperlipidemia (70%), and diabetes (46%). Pre-operative computed tomography demonstrated SFA lesions were predominantly eccentric (91%) with mild to moderate calcification (90%). All underwent PTA, 87% were stented (mean stent length: 186.1 mm), mean crossing time was 13.4 min. Pre-operative, 30-day, 6-month, and 1-year post-operative mean Rutherford-Becker scores were 4, 1, 1, and 1, respectively (p < 0.0001). Mean pre-operative ABI was 0.49, compared to 0.84 at 30 days, 0.64 at 6 months, and 0.67 at 1 year (p < .0001). Duplex demonstrated 6- and 12-month primary patency of 89% and 75%; primary-assisted patency was 94% and 84%.

CONCLUSIONS

The OCT imaging catheter successfully crossed long chronic total occlusions of the SFA using direct intra-arterial imaging. Compared to subintimal techniques, patients had high 1-year primary patency and prolonged symptom improvement with intraluminal crossing. These data suggest that intraluminal crossing of TASC D lesions may be superior to traditional subintimal crossing techniques.

Optical coherence tomography in peripheral arterial disease: A systematic review

BACKGROUND

Optical coherence tomography (OCT) is a novel adjunct in the field of medicine. The objective of this systematic review was to evaluate the role of OCT in the field of contemporary endovascular surgery in terms of its utility in diagnostics and interventions in peripheral arterial disease (PAD).

METHOD

A systematic search of literature published from 1st January 2009 to 1st August 2019 was identified from PubMed, Ovid and Cochrane library database with reference to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The pre-defined selection inclusion criteria were clinical applications of OCT in vascular surgery in relation to diagnostics and interventions. Keywords used included OCT, PAD, endovascular procedures and atherectomy.

RESULTS

From an initial search of 310 articles, 27 articles were included in this systematic review: 15 articles were related to diagnostics: peripheral arterial disease was the most studied condition (n = 8), other conditions included in-stent restenosis (n = 4), fibromuscular dysplasia (n = 2) and acute limb ischaemia (n = 1); 12 articles were related to intervention: an OCT-guided crossing catheter was the most used assisting device (n = 10), with an OCT-guided atherectomy device used in four of these studies.

CONCLUSION

Although there is currently no level 1 evidence to suggest routine use of OCT in the diagnosis and treatment of PAD, current literature suggests that the use of OCT is safe and effective. The OCT real-time vessel wall structural images clearly distinguish normal anatomy from plaque pathology, and are of great advantage both in the accurate diagnosis and treatment of target lesion, especially in reducing the amount of radiation in the endovascular procedure.

Optical coherence tomography and plaque morphology for revascularization of the superficial femoral artery

Background

The optical coherence tomography (OCT) catheter, Ocelot (Avinger Inc., Redwood City, CA), has been utilized to cross Trans-Atlantic Inter-Society Consensus Document (TASC) D lesions. Studies have assessed the characteristics of high-risk plaques in the carotid artery, but few, if any data exist evaluating OCT and plaque morphology in the superficial femoral artery (SFA). This study assessed SFA plaque morphology using OCT and lesion crossing success in chronic total occlusions (CTOs).

Methods

We reviewed patients who underwent attempted infrainguinal revascularization with TASC D CTOs using the Ocelot catheter between June 2014 and June 2018, and recorded demographic information, smoking status, and medical comorbidities. A matched cohort of 44 successfully crossed lesions was compared to 44 that failed; images insufficient for analysis were excluded. The morphology of the plaque was studied using OCT at the proximal cap, midpoint of the lesion, and the distal cap. Morphologic data studied included the intima-media thickness ratio, cross-sectional area of the plaque, and gray-scale median of the plaque.

Results

A total of 140 patients who underwent lower extremity procedures for TASC D lesions of the SFA with OCT imaging were reviewed with a crossing rate of 69.0%. No significant differences were found between crossed and uncrossed lesions for intima-media thickness or cross-sectional area at the proximal cap, the midpoint, or the distal cap. A lower gray-scale median at the proximal cap was associated with the ability to cross the chronic SFA occlusion (P=0.05). Subgroup analysis stratified by smoking and calcium content also demonstrated that a lower gray-scale median at the proximal cap was associated with the ability to cross the chronic SFA occlusion (P=0.01 and P=0.04, respectively).

Conclusions

Lower gray-scale median at the proximal cap of a chronic SFA occlusion calculated using OCT images was associated with the ability to successfully cross the lesion. Higher plaque gray-scale median is correlated with increased calcium, greater fibrous tissue, and signal-rich plaques. Gray-scale median in the proximal cap is useful marker to determine plaque composition and subsequent technical success for crossing chronic SFA occlusions. Further studies are needed to fully determine the utility of OCT images to predict successful endovascular revascularization of chronic SFA occlusions.

A post-market, multi-vessel evaluation of the imaging of peripheral arteries for diagnostic purposeS comparing optical Coherence tomogrApy and iNtravascular ultrasound imaging (SCAN)

Background

Intravascular imaging plays an important part in diagnosis of vascular conditions and providing insight for treatment strategy. Two main imaging modalities are intravascular ultrasound (IVUS) and optical coherence tomography (OCT). The objective of this study was to prove non-inferiority of OCT imaging to IVUS images in matched segments of peripheral vessels in patients with suspected peripheral vascular disease.

Methods

The SCAN study was a prospective, non-inferiority clinical study of matched IVUS and OCT images collected along defined segments of peripheral vessels from twelve subjects (mean age 68 ± 10.3 years; 10 men) displaying symptoms of vascular disease. Luminal diameters were measured by both imaging systems at the distal, middle, and proximal points of the defined segments. Three blinded interventional radiologists evaluated the quality of both imaging modalities in identifying layered structures (3-point grading), plaque (5-point grading), calcification (5-point grading), stent structure (3-point grading), and artifacts (3-point grading) from 240 randomly ordered images. Mean grading scores and luminal diameters were calculated and analyzed with Student’s t-Test and Mann-Whitney-Wilcoxon testing. Intrareader reproducibility was calculated by intraclass correlation (ICC) analysis.

Results

The mean scoring of plaque, calcification, and vascular stent struts by the three readers was significant better in terms of image quality for OCT than IVUS (p < 0.001, p = 0.001, p = 0.004, respectively). The mean scores of vessel wall component visibility and artifacts generated by the two imaging systems were not significantly different (p = 0.19, p = 0.07, respectively). Mean vessel luminal diameter and area at three specific locations within the vessels were not significantly different between the two imaging modalities. No patient injury, adverse effect or device malfunction were noted during the study.

Conclusions

Imaging by OCT provides the physician with better visualization of some vessel and plaque chacteristics, but both IVUS and OCT imaging are safe and effective methods of examining peripheral vessels in order to perform diagnostic assessment of peripheral vessels and provide information necessary for the treatment strategy of peripheral artery disease.

Trial registration

NCT03480685 registered on 29 March 2018.