Stroke

Imaging identified multiple blockages in 10.7% of patients, but nearly half of those went unnoticed during the initial diagnostic work-up.

One in 10 patients being considered for endovascular therapy to treat a large-vessel occlusion have more than one blockage, according to recently published registry data. These multivessel occlusions (MVOs) appear to carry consequences, researchers found, yet nearly half of cases were initially overlooked on imaging.

“Occurrence of MVO has implication for treatment decisions, negatively affects endovascular treatment success, and is predictive of worse clinical outcomes,” write lead authors Johannes Kaesmacher, MD, and Pascal J. Mosimann, MD (University of Bern, Inselspital, Switzerland), in their paper published online earlier this month in Stroke.

The researchers reviewed prospective registry data collected on 720 patients who were slated to undergo endovascular therapy between January 2012 and July 2017 at a single comprehensive stroke center. Around 12% ultimately underwent intra-arterial thrombolysis with urokinase, 10% did not undergo any intervention, and the remaining patients were treated with second-generation thrombectomy devices with or without intra-arterial urokinase.

Multiple occlusions were seen in 10.7% of patients on the initial diagnostic work-up, which consisted of either standardized 1.5T/3T MRI or computed tomography. While most of these 77 individuals had two occlusions (80.5), some had three (16.9%) or even four occlusions (2.6%). About one-third were downstream MVOs (35.1%), while the rest were in different territories. The most common pattern for MVO was middle cerebral artery (M1 or M2) plus anterior cerebral artery occlusions, seen in 29.9% of cases. The majority (85.7%) had a possible common cervical origin.

Importantly, only 54.5% of the MVOs were detected on the initial radiological report.

Multivariate logistic regression analysis showed that patients with MVO tended to have higher baseline systolic blood pressure and a primary occlusion site at the M2 and were less likely to be receiving statins.

Predictors of MVO

After adjustment, patients with MVO also were less likely to have successful reperfusion and to have good functional outcome at 90 days (defined as mRS score ≤ 2).

Patients With vs Without MVO: Outcomes

“Generally, multiple intracerebral emboli are thought to arise from unstable thromboembolic sources and are predictive of stroke recurrence at day 90,” the study authors point out. “In our series, however, we did not find a specific correlation between MVO occurrence and pathogenic stroke mechanism. Moreover, recent echocardiographic analyses failed to demonstrate more frequent aortic or cardiac embolic sources in patients with acute strokes involving different territories: internal carotid artery left versus internal carotid right versus vertebrobasilar.”

Here, there are hints that higher arterial blood pressure may instead be responsible, though the researchers “stress that no definitive conclusion can be drawn regarding the causality of this association.”

It’s possible that MVOs may themselves trigger a hypertensive response, they explain. “On the contrary, it is conceivable that higher systolic blood pressure may facilitate MVO by increasing the risk of clot fragmentation once it is lodged at a cervical or intracranial bifurcation. . . . Future studies are necessary to assess the true interdependence of high systolic blood pressure and MVO occurrence.”

Kaesmacher and colleagues point out that MVO was not reported in pivotal thrombectomy trials or in recent registries. “In light of the present report, MVO should be carefully assessed before including LVO patients in future randomized controlled trials,” they stress. “As endovascular techniques continue to evolve, new endovascular options may enable a safer mechanical approach for coincidental occlusions in the future, and intra-arterial thrombolysis may be considered in distal concomitant occlusions, once an intracranial access was already established.”

Sources:

Kaesmacher J, Mosimann PJ, Giarrusso M, et al. Multivessel occlusion in patients subjected to thrombectomy: prevalence, associated factors, and clinical implications. Stroke. 2018;Epub ahead of print.

Disclosures:

• The study was supported by the Swiss Stroke Society, the Bangerter Foundation, and the Swiss Academy of Medical Sciences through the Young Talents in Clinical Research program.
• Kaesmacher reports no relevant conflicts of interest.
• Mosimann receives research grants from the Swiss National Science Foundation to study new therapeutic options for cerebral aneurysms.