Exploring the relationship between embolic acute stroke distribution and supra-aortic vessel patency: key findings from an in vitro model study

BACKGROUND

We investigated differences in intracranial embolus distribution through communicating arteries in relation to supra-aortic vessel (SAV) patency.

METHODS

For this experimental analysis, we created a silicone model of the extracranial and intracranial circulations using a blood-mimicking fluid under physiological pulsatile flow. We examined the sequence of embolus lodgment on injecting 104 frangible clot analogues (406 emboli) through the right internal carotid artery (CA) as SAV patency changed: (a) all SAV patent (baseline), (b) emboli from a CA occlusion, (c) emboli contralateral to a CA occlusion and (d) occlusion of the posterior circulation. The statistical analysis included a descriptive analysis of thrombi location after occlusion (absolute and relative frequencies). Sequences of occlusions were displayed in Sankey flow charts for the four SAV conditions. Associations between SAV conditions and occlusion location were tested by Fisher's exact test. Two-sided p values were compared with a significance level of 0.05.

RESULTS

The total number of emboli was 406 (median fragments/clot: 4 (IQR: 3-5)). Embolus lodgment was dependent on SAV patency (p<0.0001). In all scenarios, embolism lodging in the anterior cerebral artery (ACA) occurred after a previous middle cerebral artery (MCA) embolism (MCA first lodge: 96%, 100/104). The rate of ipsilateral ACA embolism was 28.9% (28/97) at baseline, decreasing significantly when emboli originated from an occluded CA (16%, 14/88). There were more bihemispheric embolisations in cases of contralateral CA occlusion (37%, 45/122), with bilateral ACA embolisms preceding contralateral MCA embolism in 56% of cases (14/25 opposite MCA and ACA embolism).

CONCLUSIONS

All emboli in the ACA occurred after a previous ipsilateral MCA embolism. Bihemispheric embolisms were rare, except when there was a coexisting occlusion in either CA, particularly in cases of a contralateral CA occlusion.

Characteristics of Multiple Acute Concomitant Cerebral Infarcts Involving Different Arterial Territories

(1) Background: Multiple acute concomitant cerebral infarcts (MACCI) are relatively uncommon. Data regarding the characteristics and outcomes of patients with MACCI are lacking. We, therefore, aimed to characterize the clinical features of MACCI. (2) Methods: Patients with MACCI were identified from a prospective registry of stroke patients admitted to a tertiary teaching center. Patients with an acute single embolic stroke (ASES) involving only one vascular bed served as controls. (3) Results: MACCI was diagnosed in 103 patients who were compared to 150 patients with ASES. MACCI patients were significantly older (p = 0.010), more often had a history of diabetes (p = 0.011) and had lower rates of ischemic heart disease (p = 0.022). On admission, MACCI patients had significantly higher rates of focal signs (p < 0.001), an altered mental state (p < 0.001) and seizures (p = 0.036). The favorable functional outcome was significantly less common in patients with MACCI (p = 0.006). In the multivariable analysis, MACCI was associated with lower chances of achieving favorable outcomes (odds ratio: 0.190, 95% CI: 0.070-0.502). (4) Conclusions: There are important differences in clinical presentation, comorbidities and outcomes between MACCI and ASES. MACCI is less often associated with favorable outcomes and could represent a more severe form of a stroke compared with a single embolic stroke.

Clinical manifestation of acute cerebral infarcts in multiple arterial territories

OBJECTIVES

We aimed to assess frequencies and radiological aspects of single- and multiterritory clinical manifestation among patients with acute cerebral infarcts in multiple arterial territories (MACI).

MATERIALS & METHODS

We retrospectively reviewed admission records and diffusion-weighted magnetic resonance imaging of patients with MACI admitted to our stroke unit between 2006 and 2017. MACI was defined as acute cerebral ischemic lesions in at least two out of three arterial cerebral territories, that is, the left anterior, right anterior and the bilateral posterior territory. Patients with single- and multiterritory clinical manifestation were then compared for topographical distribution of the ischemic lesions, the number of ischemic lesions, and The Oxfordshire Community Stroke Project classification.

RESULTS

Out of 311 patients with MACI, 222 (71.4%) presented with single-territory clinical manifestation. Involvement of the left hemisphere (OR = 0.37, 95% CI 0.16-0.82), less than five ischemic lesions (OR = 0.58, 95% CI 0.35-0.97), and partial anterior circulation infarct clinical stroke syndrome (OR = 0.57, 95% CI 0.34-0.97) were associated with single-territory clinical manifestation. Involvement of all three territories (OR = 2.58, 95% = 1.48-4.50), more than 10 ischemic lesions (OR = 2.30, 95% CI 1.32-4.01) and total anterior circulation infarct clinical stroke syndrome (OR = 3.31, 95% CI 1.39-7.86) were associated with multiterritory clinical manifestation.

CONCLUSION

Most patients with MACI present with single-territory clinical manifestation on admission. Diffusion-weighted magnetic resonance imaging is therefore necessary for a definite diagnosis.

Thirty-day recurrence after ischemic stroke or TIA

BACKGROUND

Incidence of recurrent stroke is highest within 30 days after the initial ischemic stroke (IS) or TIA, but knowledge about early recurrence is lacking. We aimed to identify etiological groups with highest risk of early recurrence and assess how the TOAST classification identified index stroke etiology.

METHODS

Medical records of 1874 IS and TIA patients in the Bergen NORSTROKE registry were retrospectively reviewed for identification of recurrent IS or TIA within 30 days after index IS or TIA. Stroke etiology was determined by review of electronical medical journals. Logistic regression was used to calculate odds ratios (OR) for 30-day recurrence.

RESULTS

Thirty-three patients (1.8%) were readmitted with recurrent IS or TIA within 30 days after index stroke. By using TOAST, 12 patients were initially classified with stroke of unknown etiology (SUE). Etiologies behind recurrent IS or TIA were after the recurrent episode identified as extracranial large artery atherosclerosis (LAA) in 14 patients (42.4%), intracranial arterial pathology in seven patients (21.2%), active malignancy in six patients (18.2%), and cardio embolism in four patients (12.1%). Small vessel occlusion and SUE were the causes in one patient each. Logistic regression showed that patients with stroke of other determined etiology (SOE) and LAA had increased risk of 30-day recurrence (OR = 9.72, 95% CI 1.84-51.3, p < 0.01 and OR = 4.36, 95% CI 2.01-9.47, p < 0.01, respectively).

CONCLUSION

Patients with LAA and SOE had increased risk of recurrent IS or TIA within 30 days. TOAST was inadequate at identifying exact etiologies behind recurrent stroke at index event.