Sebastian FischerSebastian Fischer
Findings from a retrospective analysis of patients with acute ischemic stroke (AIS) with large-vessel occlusion due to calcified emboli demonstrated poor results associated with mechanical thrombectomy, with worse angiographic outcomes and higher mortality rates compared with patients with noncalcified thrombi.

The retrospective, multicenter study analyzed data from patients with AIC who underwent mechanical thrombectomy intracranial large-vessel occlusion due to a calcified embolus diagnosed on unenhanced CT. The investigators defined a calcified embolus as “an oblong, not circular or semicircular, calcification with clearly intraluminal localization on CT angiography at the site of intracranial vessel occlusion.”

Investigators collected a multitude of data samples, including National Institute of Health Stroke Scale (NIHSS) scores and modified Rankin Scale (mRS) scores following admission and discharge. Cardiovascular risk factors were also documented after 90 days of discharge. Other metrics evaluated included the time of symptom onset, hospital admission, first imaging, groin puncture, and recanalization. Other imaging data collected during the study included the Alberta Stroke Program Early CT Score (ASPECTS) at admission and after 24 hours, and intracranial hemorrhage according to the European Cooperative Stroke Study (ECASS).

Thrombus related metrics evaluated in the study were the localization, length, and density together with the presumed source of the embolus, and the existence of multiple calcified emboli and concomitant extracranial stenosis. Using the modified treatment in cerebral ischemia (mTICI) score, investigators assessed angiographic outcomes. Other complications, medication during the procedure, materials, and number of passes were all recorded as procedural data.

Of 2969 patients who underwent mechanical thrombectomy,  40 matched inclusion criteria (1.3%; 68% women, mean age, 77.9+ 9.6 years). The mean NIHSS score on admission was 15.4+7.2 and the median initial ASPECTS was 9 (interquartile range, 7-9).
 
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Data revealed the mean maximal density of the thrombus was 327 Hounsfield Unit (HU) (range, 150-1200 HU), with a mean thrombus length of 9.2 mm (range, 4-20 mm).

Patients whose source of embolization was unknown accounted for 37.5% of the cohort, while cardiac, aortic, and internal carotid artery (ICA) was the source of embolization in 17.5%, 15%, and 30%, respectively. Investigators noted that 4 patients had multiple calcified emboli, and 2 patients had an embolic event during endovascular intervention.

Of the 40 patients observed, 23 (57.5%) had good angiographic outcome (mTICI score of >2b), compared to 13 of 40 (32.5%) patients with minimal-to-no reperfusion (mTICI 0-1). Incomplete reperfusion was reported in 4 patients (10%) in the study.

Clinical outcomes at 90 days were observed in 34 patients, of which 7 (20.1%) achieved excellent outcome on the mRS scale and 9 (26.5%) achieved functional independence. The mortality rate at 90 days was 55.9% (19/34).

Overall, the investigators concluded that based on the findings, good functional outcome can be expected in approximately 1 in 4 patients in this rare population.
REFERENCE
Maurer CJ, Dobrocky T, Joachimski F, et al. Endovascular thrombectomy of calcified emboli in acute ischemic stroke: a multicenter study. AJNR. Published online February 6, 2020. doi: 10.3174/ajnr.a6412.