Lukas Mayer, MD
The search for characteristic features of underlying vasculopathy and/or connective tissue disease in patients with spontaneous cervical artery dissection has been going on for quite some time now, more recently yielding progress on multiple levels. Especially in vascular imaging, the coexistence of radiological hallmarks supposedly attributed to fibromuscular dysplasia (FMD) has been of interest in these subjects.
Through their recently published study, Bonacina et al. add to this interesting and highly relevant topic. The authors reviewed case files and imaging data of 1283 subjects enrolled in the multicenter Italian Project of Stroke in Young Adults Cervical Artery Dissection (IPSYS CeAD) study with the inclusion criterion being first-ever spontaneous cervical artery dissection (sCeAD) between January 2000 and June 2019. Through their work-up, they generated a cohort clinically consistent with most previously described sCeAD studies, as patients were in their mid 40s at sCeAD onset, males predominated, coexistent cerebrovascular risk factors were infrequent at baseline and cerebral ischemia was evident in more than 80% of sCeAD cases. Solely, the 60 to 40% split of internal carotid to vertebral artery affection might suggest an older sample of patients as more recent sCeAD-cohorts support an equal distribution of anterior and posterior circulation dissection. The latter has predominantly been attributed to the increased availability of advanced cerebrovascular imaging (e.g., 3T MRI – fat saturated T1 imaging). In 8% of subjects, according to the most recent expert consensus guidelines, vascular imaging was consistent with cerebrovascular FMD. Acute management and clinical manifestation did not differ in those with or without these signs. Subjects did, however, differ in some demographics and clinical characteristics, as those with imaging findings suggestive of FMD were more frequently women, more likely to have intracranial aneurysms and first-degree relatives with sCeAD. Upon follow-up, they also were more likely to have pseudoaneurysms, multivessel involvement of sCeAD and sCeAD recurrence. Bonacina et al. further describe pathophysiological mechanisms possibly linking migraine with aura, cerebrovascular FMD and sCeAD.
As promising as the premise of FMD in sCeAD seems to be, there are still questions left to be answered. Most pressing, along with previous studies analyzing the correlation or causal connection of FMD to sCeAD, the FMD-diagnosis has been established indirectly by the use of cerebrovascular imaging only. As biopsies of affected arteries are hard to come by, this is to be expected. Still, it is important to scrutinize the attribution of sCeAD-associated vasculopathies to FMD only. The characteristics employed to diagnose FMD through cerebrovascular imaging cannot definitively differentiate between FMD and other generalized vasculopathies.
Accordingly, evidence of one of the factors proposed by the European expert consortium in 2014 in the definition of FMD, the “disease of the musculature of arterial walls,” is missing.
Still, Bonacina et al. publish valuable results emphasizing the existence of a generalized vasculopathy in sCeAD patients, as well as the risk of dissection recurrence in subjects with these findings in vascular imaging. Whether the underlying vasculopathy, in fact, is FMD or not remains open to discussion.
