Act II: Multiple Idiopathic Cervical-Cranial Arterial Dissections in Two Acts.

Her cervical MRA revealed apparent healing of her left ICA and both VAs. There was, however, again a high-grade stenosis of her right ICA (Fig 1). Brain MRI revealed areas suspicious for microbleeds in the previously infarcted watershed area (Fig 2).

Figure 1. Neck MRA over one year following the diagnosis of bilateral internal carotid artery (ICA) and vertebral artery (VA) dissections. The right ICA shows minimal vascular filling (arrow; proximal stump, asterisk). The remaining cervical arteries appear essentially normal.

Figure 2. T2-weighted brain MRI with possible microbleed (arrow) under combined oral antiplatelet and anticoagulation therapy.

Interestingly, selective catheter angiogram showed much more severe disease. The right ICA had a complex false and true lumen with numerous associated pseudoaneurysms (Fig 3). The left ICA showed a tight stenosis (Fig 4). Angiographic evidence of hemodynamic compromise continued to be present. Simply continuing her vigorous oral antiplatelet and anticoagulation therapy in face of possible new microbleeds and failed complete healing of the cervical dissections seemed imprudent.

Figure 3. Right common carotid artery injection showing dissection of the internal carotid artery with a flap of false lumen (indicated by white lines, arrows) and pseudoaneurysms (arrow heads).

Figure 4. Left internal carotid artery pre-angioplasty (A, B) with retrograde filling via the posterior communicating artery (washout direction, blue arrow in A; focal stenosis, yellow arrows in A and B). Carotid arteries with orthograde filling post angioplasty (C).

She was admitted for staged endovascular revascularization of both ICAs. The left tight ICA web was treated with angioplasty (pre-treatment, Fig 4 A and B vs. post-angioplasty, Fig 4 C.). Three days later, the dissected right ICA with false lumen was treated with angioplasty and stent, (pre-treatment, Fig 3) vs. (post-stenting, Fig 5). Following, hemodynamic conditions were restored.

Figure 5. Internal carotid artery post stent implant showing normal lumen without the in-stent stenosis seen previously on surveillance MRA and CTA.

In summary, this case demonstrated several angiographic findings: False/true lumens (Fig 3), a myriad of pseudo-aneurysm (Fig 6 A-C), and hyper-sensitive vessels prone to spasm during catheter manipulation (Fig 6 D, E).

Figure 6. Cervical angiogram showing multiple areas of vascular changes: small pseudoaneurysms (arrows in A, B, and C); vascular spasm seen during angioplasty of the internal carotid artery (asterisk in D and E).

Following endovascular treatment, the patient reported her energy and memory would have improved. During surveillance and one year post treatment, cervical MRA and CTA found possible intra-stent stenosis. Fortunately, this was negative on catheter-based angiogram (Fig 5). A small vertebral artery flap remained. Overall, the vessels had done a remarkable job of healing. Still undetermined, the angiographic changes and the protracted time course of over almost five years, all raise questions as to its etiology.

Discussion

As in this case, MRA and CTA can, on occasion, miss flow-limiting conditions. Small vascular webs can be difficult to identify at the base of the skull where artifacts are common. Additionally, false lumens can also be hemodynamically significant. If suspected, these can best be seen with tailored axial MRI. Furthermore, in-stent stenosis can be challenging with the metallic stent creating artifacts on any imaging modality.

The carotid artery gets its name from the Greek karos, which means “deep sleep” or “stupor“. The term was already being taught in Roman medical schools early in the first century A.D., and was quite possibly used by the Greeks 300 hundred years earlier as it was Aristotle (384-322 BCE) who first noted that pressure on the both carotid arteries could induce a stupor[1]. Carotid stenosis is clearly associated with cognitive impairment. There is, however, only tantalizing evidence that treating the stenosis corrects the cognitive impairment. Threshold effects [2], morbidity of the intervention[3], and progression of the disease, test and retest measures of cognitive function, and placebo and nocebo effects make this a difficult area of study. Fortunately, in this young lady, the reconstitution of normal blood flow was beneficial.

Blood ‘thinning’ with both anti-platelet and anticoagulant is not without risk. For routine situations, the literature offers clear guidance[4].

As performed in this patient, angioplasty without stenting is an excellent minimally invasive treatment for non-atherosclerotic symptomatic focal narrowing of the ICA. Placement of a stent across areas that are both highly mobile, i.e. the neck, and fixed, i.e. the base of the skull, can lead to early stenosis, and pain. However, as demonstrated here, stenting for false and true lumen dissections can be done successfully with good results long-term.

Finally, what is this lady’s condition? Perhaps somewhat comfortable, but not unsuited, one would call this FMD or fibromuscular dysplasia[5] per consensus nomenclature. We may someday retire and replace this word as we did Dropsy (for edema), Bright disease (for glomerulonephritis), and Carotidynia (for idiopathic neck and face pain) for etiologically more robust words that unveil our ignorance.

Acknowledgment:

Our thanks to Dr. Husain Mahmood Rizvi, MD, for his partnership in this patient’s care and for his insights for the preparation of this article

References

[1]Anatomy Words. Dr. A. C. Carpenter, 9/20/07 at https://anatomyalmanac.blogspot.com/.

[2] Marshall R, S, Pavol M, A, Cheung Y, K, Asllani I, Lazar R, M: Cognitive Impairment Correlates Linearly with Mean Flow Velocity by Transcranial Doppler below a Definable Threshold. Cerebrovasc Dis Extra 2020;10:21-27. doi: 10.1159/000506924

[3] Traenka C, Engelter ST, Brown MM, Dobson J, Frost C, Bonati LH. Silent brain infarcts on diffusion-weighted imaging after carotid revascularisation: A surrogate outcome measure for procedural stroke? A systematic review and meta-analysis. Eur Stroke J. 2019;4(2):127-143. doi:10.1177/2396987318824491

[4] Serrano CV Jr, Soeiro AM, Leal TCAT, et al. Statement on Antiplatelet Agents and Anticoagulants in Cardiology – 2019. Arq Bras Cardiol. 2019;113(1):111-134. Published 2019 Aug 8. doi:10.5935/abc.20190128

[5] Fibromuscular Dysplasia: State of the Science and Critical Unanswered Questions A Scientific Statement From Olin JW, Gornik HL, Bacharach JM, Biller J, Fine LJ, Gray BH, et al. Fibromuscular dysplasia: state of the science and critical unanswered questions: a scientific statement from the American Heart Association. Circulation. 2014 Mar 4;129(9):1048-78. doi: 10.1161/01.cir.0000442577.96802.8c. Epub 2014 Feb 18. PMID: 24548843.