Background and Purpose: Craniocervical fibromuscular dysplasia (FMD) has been associated with dissections. Recently, the presence of an S-shaped curve in the ICA has been described as a marker of FMD. We evaluated the occurrence of S-shaped curves in acute ischemic stroke (AIS) patients presenting with ICA steno-occlusive dissections.
Methods: This was a retrospective review of the interventional database of two academic tertiary care institutions. Cases of carotid dissections were compared with a control group (consecutive non-tandem anterior circulation strokes). The presence of ICA S-shaped curves, C-shaped curves, 360° loops, as well as, FMD changes and atherosclerotic changes at the ICA bulb and curve/loop was determined by evaluation of conventional-angiogram and CTA.
Results: Twenty-four patients with carotid dissections were identified and compared to 92 controls. The baseline characteristics were similar, with the exception of expected younger age and less prevalent history of hypertension, diabetes and atrial fibrillation in the dissection group. Procedural variables were also similar, with the exception of a large percentage of the use of stentretrievers in the control group. The occurrence of parenchymal hemorrhages, good outcomes and mortality were similar amongst the two groups. The frequency of S-shaped curves on either side was 29% in the dissection group vs. 7% in the control group (p<0.01). The S-shaped ICA curves were typically mirror images within the dissection group (85% of the patients with an S-shaped curves had bilaterally occurrence). The frequency of C-shaped and 360 degree curves was statistically similar between groups. FMD changes within the craniocervical arteries were statistically more common in the patients with dissections. Ten patients of the dissection group had either FMD changes or an S-Shaped curve (41%). Multivariate analysis indicated that S-shaped curves were independently associated with the presence of dissections.
Conclusion: S-shaped ICA curves are predictably bilateral, independently associated with carotid dissections in patients undergoing thrombectomy for acute ischemic stroke, and may indicate the underlying presence of FMD.