A Protocol-Based Decision for Choosing a Proper Surgical Treatment Option for Carotid Artery Stenosis

Modality-specific outcomes of patients undergoing carotid revascularization in the setting of recent myocardial infarction

OBJECTIVE

Recent myocardial infarction (MI) represents a real challenge in patients requiring any vascular procedure. There is currently a lack of data on the effect of preoperative MI on the outcomes of carotid revascularization methodology (carotid enterectomy [CEA], transfemoral carotid artery stenting [TFCAS], or transcarotid artery revascularization [TCAR]). This study looks to identify modality-specific outcomes for patients with recent MI undergoing carotid revascularization.

METHODS

Data was collected from the Vascular Quality Initiative (2016-2022) for patients with carotid stenosis in the United States and Canada with recent MI (<6 months) undergoing CEA, TFCAS, or TCAR. In-hospital outcomes after TFCAS vs CEA and TCAR vs CEA were compared. TCAR vs TFCAS were compared in a secondary analysis. We used logistic regression models to compare the outcomes of these three procedures in patients with recent MI, adjusting for potential confounders. Primary outcomes included 30-day in-hospital rates of stroke, death, and MI. Secondary outcomes included stroke/death, stroke/death/MI, postoperative hypertension, postoperative hypotension, prolonged length of stay (>2 days), and 30-day mortality.

RESULTS

The final cohort included 1217 CEA (54.2%), 445 TFCAS (19.8%), and 584 TCAR (26.0%) cases. Patients undergoing CEA were more likely to have prior coronary artery bypass graft/percutaneous coronary intervention and to use anticoagulant. Patients undergoing TFCAS were more likely to be symptomatic, have prior congestive heart failure, chronic obstructive pulmonary disease, chronic kidney disease, and undergo urgent operations. Patients undergoing TCAR were more likely to have higher rates of American Society of Anesthesiologists class IV to V, P2Y12 inhibitor, and protamine use. In the univariate analysis, CEA was associated with a lower rate of ipsilateral stroke (P = .079), death (P = .002), and 30-day mortality (P = .007). After adjusting for confounders, TFCAS was associated with increased risk of stroke/death (adjusted odds ratio [aOR], 2.69; 95% confidence interval [CI], 1.36-5.35; P = .005) and stroke/death/MI (aOR, 1.67; 95% CI, 1.07-2.60; P = .025) compared with CEA. However, TCAR had similar outcomes compared with CEA. Both TFCAS and TCAR were associated with increased risk of postoperative hypotension (aOR, 1.62; 95% CI, 1.18-2.23; P = .003 and aOR, 1.74; 95% CI, 1.31-2.32; P ≤ .001, respectively) and decreased risk of postoperative hypertension (aOR, 0.59; 95% CI, 0.36-0.95; P = .029 and aOR, 0.50; 95% CI, 0.36-0.71; P ≤ .001, respectively) compared with CEA.

CONCLUSIONS

Although recent MI has been established as a high-risk criterion for CEA and an approved indication for TFCAS, this study showed that CEA is safer in this population with lower risk of stroke/death and stroke/death/MI compared with TFCAS. TCAR had similar stroke/death/MI outcomes in comparison to CEA in patients with recent MI. Further prospective studies are needed to confirm our findings.

The clinical application of a scoring protocol to select endarterectomy or stenting for carotid artery stenosis

Previously we described the protocol-based decision for choosing the proper surgical treatment option for carotid stenosis. The objective of this study is to describe our experiences of using this scoring protocol in the selection of endarterectomy or stenting for carotid stenosis. Between October 2014 and March 2018, the scoring protocol was applied to a total of 105 consecutive patients. Eighty (76.2%) patients had symptomatic stenosis ≥ 50%, and 25 (23.8%) patients had asymptomatic stenosis ≥ 80%. We also speculated about how effectively the protocol worked in the real clinical setting. Stenting was performed in 73 patients and endarterectomy in 32 patients. Overall, 98 (93.3%) patients were treated according to the protocol, while the protocol was violated in seven (6.7%) patients. Sixty-one (58.1%) patients received treatments that were decided by the protocol. There were 37 (35.2%) patients who had the same score for both treatment options. Among these patients, 28 patients underwent stenting and nine patients underwent endarterectomy. In the stenting cases, 90.4% of the patients followed the protocol and violations occurred in 9.6%. In the endarterectomy cases, all of the patients followed the protocol. Overall, one patient had a procedure-related complication without morbidity. During the 12-month follow-ups, there were no restenoses or major strokes. Minor strokes were diagnosed in three (2.8%) patients. In patients with carotid artery stenosis, stenting and endarterectomy should be considered simultaneously together, not against each other. Our scoring protocol can be used to weigh these options and applied in clinical practice.

Blocked Filter of Anti-Embolic Device During Carotid Artery Stenting: A Rare Occurrence Posing Challenging Diagnostic Dilemma

The use of anti-embolic devices (AED’s) is a common practice in carotid artery stenting (CAS). It prevents the passage of blood clots and thrombi generated during the procedure from embolizing into the intracranial circulation. Disadvantages include the passage of small particles and complications related to advancement, deployment, and recovery of the filters. The filter of the AED can get clogged due to the high load of the emboli generated during CAS causing a slowing of the intracranial blood flow which normalizes once the filter is removed.

Here, we are presenting a case of the filter of AED getting blocked due to entrapped thrombi or blood clots and mimicking dissection and, sharing our experiences associated with the event.

Dual Energy Computed Tomography of Internal Carotid Artery: A Modified Dual-Energy Algorithm for Calcified Plaque Removal, Compared With Digital Subtraction Angiography

Background: Atherosclerotic disease of the internal carotid artery (ICA) is a common reason for ischemic stroke. Computed tomography angiography (CTA) is a common tool for evaluation of internal carotid artery (ICA) stenosis. However, blooming artifacts caused by calcified plaques might lead to overestimation of the stenosis grade. Furthermore, the intracranial ICA is more vulnerable to calcification than other ICA segments. The proposed technique, dual-energy computed tomography (DECT) with a modified three-material decomposition algorithm may facilitate the removal of calcified plaques and thus increase diagnostic accuracy.

Objectives: The objective of the study is to assess the accuracy of the modified three-material decomposition algorithm for grading intracranial ICA stenosis after calcified plaque removal, with digital subtraction angiography (DSA) used as a reference standard.

Materials and Methods: In total, 41 patients underwent DECT angiography and DSA. The three-material decomposition DECT algorithm for calcium removal was applied. We evaluated 64 instances of calcified stenosis using conventional CTA, the previous non-modified calcium removal DECT technique, the modified DECT algorithm, and DSA. The correlation coefficient (r²) between the results generated by the modified algorithm and DSA was also calculated.

Results: The virtual non-calcium images (VNCa) produced by the previous non-modified calcium removal algorithm were named VNCa 1, and those produced by the modified algorithm were named VNCa 2. The assigned degree of stenosis of VNCa 1 (mean stenosis: 39.33 ± 19.76%) differed significantly from that of conventional CTA images (mean stenosis: 59.03 ± 25.96%; P = 0.001), DSA (13.19 ± 17.12%, P < 0.001). VNCa 1 also significantly differed from VNCa 2 (mean stenosis: 15.35 ± 18.70%, P < 0.001). In addition, there was a significant difference between the degree of stenosis of VNCa 2 and conventional CTA images (P < 0.001). No significant differences were observed between VNCa 2 and DSA (P = 0.076). The correlation coefficient (r²) between the stenosis degree of the VNCa 2 and DSA images was 0.991.

Conclusions: The proposed DECT with a modified three-material decomposition algorithm for calcium removal has high sensitivity for the detection of relevant stenoses, and its results were more strongly correlated with DSA than with those of conventional CTA or the previous non-modified algorithm. Further, it overcomes CTA's previous problem of overestimating the degree of stenosis because of blooming artifacts caused by calcified plaques. It is useful to account for calcified plaques while evaluating carotid stenosis.

Relationship between carotid plaque characteristics and new ischemic lesions after stenting detected by computed tomography angiography

Background

Although carotid artery stenting achieves definite benefits, it carries a higher rate of embolization compared with carotid endarterectomy. The incidence of embolization may be related to plaque stability.

Purpose

To assess for any relationship between plaque characteristics and cerebral emboli following carotid artery stenting.

Material and Methods

Sixty-three patients with severe carotid stenosis underwent carotid artery stenting. They were divided into two groups according to whether new ischemic lesions were detected on diffusion-weighted imaging after carotid artery stenting. We evaluated the types and locations of calcification in plaques and extent of calcification. We then assessed for a correlation between each of these factors and occurrence of new lesions on diffusion-weighted imaging after carotid artery stenting.

Results

The locations of calcification, percentage of plaque enhancement, and the number of plaques with irregular surface or ulceration were significantly different between the two groups. A peripheral position of calcification (close to the adventitia), enhancing plaques, and plaques with irregular surfaces or ulceration were statistically significant predictors of intracerebral embolization after carotid artery stenting. No significant differences in type of plaque or degree of calcification were found between two groups.

Conclusion

Peripheral calcification, enhancing plaques, and plaques with irregular surfaces were risk factors for intracerebral embolization after carotid artery stenting. These plaque characteristics should be considered when choosing the optimal treatment for patients.

Optimal platelet function test for in-stent tissue protrusion following carotid artery stenting

Purpose

To determine the best platelet function test for in-stent tissue protrusion following carotid artery stenting (CAS).

Methods

Patients who underwent CAS were recruited prospectively in this observational study. Combination of aspirin 100 mg/day and clopidogrel 75 mg/day was administered for a minimum of 7 days prior to procedure. Platelet aggregation was measured by light transmittance aggregometry (LTA) following stimulation by adenosine diphosphate (ADP), collagen, and thrombin receptor activating peptide (TRAP) and by the point of care assay, VerifyNow which measures aspirin and thienopyridine reaction units.

Results

In-stent tissue protrusion with maximum projection area of ≥1 mm² was detected by optical coherence tomography (OCT) in 10/28 (36%) patients. Baseline characteristics were not significantly different between the two in-stent size groups (i.e., ≥1 mm² vs. <1 mm²) but after stimulation by collagen at 10 and 20 μg/ml, platelet reactivity as measured by LTA was significantly higher in the ≥1 mm² group compared with the <1 mm² group. No other differences in platelet function were detected.

Conclusions

Collagen-induced platelet reactivity was related to in-stent tissue protrusion size following CAS.