The results can help predict whether stent-retriever thrombectomy will be effective, Korean researchers say.
Use of computed tomographic angiography (CTA) can help to rapidly identify clot features that are present among patients with intracranial large-artery occlusion, according to a study out of Korea. Knowing what type of clot is being treated can enable interventionalists to choose appropriate endovascular therapy, according to a study published in the October 2017 issue of Stroke.
This represents a “new concept,” said Josser E. Delgado Almandoz, MD (Abbott Northwestern Hospital and St. Francis Regional Medical Center, Minneapolis, MN), who commented on the study for Neurovascular Exchange. Studies such as this one are important, he observed, now that there are two distinct thrombectomy approaches: stent-retriever and aspiration. Knowing in advance which technique is likely to be more effective can help improve clinical outcomes.
Lead author Byung Moon Kim, MD, PhD (Yonsei University College of Medicine, Seoul, Korea), told NXV in an email that they had previously introduced the idea of pinpointing occlusion type using digital subtraction angiography (DSA) in a publication last year.
“The goal of identifying occlusion type is to offer a helpful clue in judging whether the patient's arterial occlusion is embolic or nonembolic,” he explained. “This discrimination is very important, especially in the era of stent-retriever thrombectomy, because it is well-known that stent-retrievers are much less effective in cases of nonembolic arterial occlusion.”.
While DSA was found to be very useful for determining occlusion type in their original study, Kim explained that, “for an optimal endovascular strategy, it could be very helpful if one can determine occlusion type before the procedure, not during the procedure. Thus, we turned our eyes to CTA.”
The investigators retrospectively reviewed data on 238 consecutive patients with large-artery-occlusion stroke who underwent CTA followed by endovascular therapy. Patients’ mean age was 70.0 years and 52.9% were male. The investigators classified CTA-determined occlusion type into truncal-type or branching-site, comparing this with DSA-determined occlusion type during endovascular treatment. They also compared the prognostic value of CTA-determined occlusion type with atrial fibrillation and hyperdense artery sign (a possible indicator occlusion pathomechanism)
CTA-determined occlusion type corresponded adequately with DSA-determined occlusion type (P = 0.453). Both occlusion type on CTA and the presence of atrial fibrillation were independent predictors of outcome.
Independent Predictors of Success With Stent Retriever
|
|
Odds Ratio (95% CI) |
P Value |
|
CTA-Determined Occlusion Type |
8.20 (3.45-19.5) |
< 0.001 |
|
Atrial Fibrillation |
2.66 (1.25-5.66) |
0.011 |
When comparing the predictive value of each preprocedural finding, the investigators calculated that the area under the receiver operating characteristic curve value for CTA-determined branching-site occlusion (0.695) was significantly greater than that for atrial fibrillation (0.594; P = 0.038) and hyperdense artery sign (0.603; P = 0.023).
Matching Technique to Occlusion Type
“The authors were able to show with strong statistical significance that, in their patient population, stent-retrievers worked better when the occlusion was at a branching point in the artery and not in the artery's main trunk (these occlusion types may be more likely to be embolic than in-situ thrombosis),” noted Almandoz.
“In their patient population,” he continued, “identifying the occlusion type at the time of the CTA may allow the operator to choose which device to use for the thrombectomy, with a stent-retriever being chosen for branching occlusions and pharmacological thrombolysis with stenting, or possible aspiration, being chosen for truncal occlusions.”
Both experts pointed out that the study is limited by its retrospective nature and the fact that it was based on data from one center. “In addition,” noted Almandoz, “their population is affected by a relatively high prevalence of intracranial atherosclerosis, which in their cohort was probably the most likely reason for truncal type occlusions.”
Kim and his team are currently investigating the direct relationship between occlusion type and patient outcomes. “Preliminarily,” he reported, “by actively considering the occlusion type, the time to effective recanalization was shortened and patients’ clinical outcome was improved.” He expects to be able to share these data soon.
Source:
Baek JH, Kim BM, Yoo J, et al. Predictive value of computed tomography angiography-determined occlusion type in stent retriever thrombectomy. Stroke. 2017;48:2746-2752.
Disclosures:
- Kim reports no relevant conflicts of interest.
- Almandoz reports being a consultant for Penumbra.
