Complex Vascular Anatomy Problematic for Carotid Artery Stenting

My right carotid artery was 80% closed at time of stroke. My doctors at the hospital never found that. I'm glad they didn't, they probably would have put an inflexible metal stent into an artery that needs to be flexible.  I have yet to see why there is this huge compulsion to clean out or stent these arteries to the brain. If your Circle of Willis is complete then it would seem to make more sense to just close up(gluing?) that artery to prevent clots from breaking off there. My right carotid artery is now completely closed and in 10 years have had no episodes of my brain not getting enough blood.
51% of stenting cases showed strokes occurred after procedure.  That is appalling.

But don't listen to me, I have absolutely no medical training. 

https://www.medpagetoday.com/Cardiology/Atherosclerosis/64568?

• by Nicole Lou
  Reporter, MedPage Today/CRTonline.org April 13, 2017

Action Points

• Note that this secondary analysis of a randomized trial found that carotid artery stenting was associated with a much higher risk for cerebral ischemia compared with endarterectomy among individuals with complex vascular anatomy.
• Complex anatomy was not associated with a higher risk of stroke during the procedure, however.

Complex aortic arch configurations and internal carotid artery (ICA) tortuosity were bad news for carotid artery stenting, but not endarterectomy, according to an MRI substudy of the International Carotid Stenting Study (ICSS).
New ischemic brain lesions on diffusion-weighted MRI after treatment were found in 51% of cases after stenting and 16% of cases after surgery (OR 6.0, 95% CI 2.9-12.4), the paper in the May 2017 issue of Stroke showed.
With carotid artery stenting, Leo Bonati, MD, of University Hospital Basel in Switzerland, and colleagues found age-independent predictors for new brain lesions to be aortic arch configuration type 2 or 3 (OR 2.8, 95% CI 1.1-7.1) and an ICA angle of 60º or higher (OR 4.1, 95% CI 1.7-10.1).
Those whose largest ICA angle was at least 60º had a 12-fold higher risk of strokes during stenting over their peers with smaller ICA angles (OR 11.8, 95% CI 4.1-34.1).
Complex vascular anatomy was not a factor for strokes during surgery. However, aortic arch configuration types 2 and 3 did trend numerically to a higher risk for cerebral ischemia (OR 3.5, 95% CI 0.7-17.1).
Bonati's group suggested that these configurations are associated with increased atherosclerotic burden or represent markers of general vascular risk. Aortic arch type 2 was defined in the study as having at least 1 supra-aortic artery originating between the outer and inner curvature; aortic arch type 3 was for cases where there was at least 1 supra-aortic artery originated below the level of the inner curvature.
"Older age has consistently been shown a risk factor for procedural stroke in carotid artery stenting, but not in carotid endarterectomy," they wrote. "It has been speculated whether the association might be mediated by vascular anatomy."
"Elongation of the aortic arch and supraaortic arteries was found to be more prevalent in elderly patients, possibly leading to more difficulties during the carotid artery stenting procedure," they concluded. "Notably in our analysis, the associations between ICA angulation and aortic arch configuration with cerebral ischemia in the stenting group remained significant after correction for age. Hence, vascular anatomy should be taken into account when selecting the appropriate treatment option for an individual patient, independent of the patient's age."
The ICSS trial randomized 1,700 patients with symptomatic internal carotid artery stenosis to stenting or surgery. Top-line results put stenting recipients at a disadvantage for adverse events.
For this ICSS substudy, the authors included the 184 patients who got magnetic resonance (n=126) or CT angiography (n=58) at baseline on top of brain MRIs before and after treatment.
Bonati and colleagues posed several reasons why it would make sense that complex vascular anatomy has an association with procedural stroke.
"A complex configuration of the aortic arch and the supraaortic arteries increases the technical difficulty of the stent procedure," they wrote. "Repeated attempts to advance the catheter and guidewire may cause endothelial microtrauma or dislodge atherosclerotic plaque and ultimately cause cerebral emboli."
"The protocol of ICSS did not contain detailed precautions against these complications, such as advice on catheter and guidewire handling, limiting guidewire maneuver time between flushing, syringe aspiration and cleansing, concentration of heparin in saline flush, use of constant infusion via infusion ports to stopcocks, etc.," the authors noted.
"We are therefore unable to verify that all possible precautions against thromboembolism were taken," they wrote. "This limitation must be borne in mind when interpreting the results of our study."
Another limitation is the exclusion of patients with extremely unfavorable anatomy for stenting.
"The fact that the ICSS protocol excluded patients with a stenosis that was thought to be unsuitable for stenting because of proximal tortuous anatomy is likely to have limited the number of patients with very unfavorable anatomy," according to Bonati's group. "The full impact of vascular anatomy on carotid artery stenting risk may therefore have been underestimated in this study."

ICSS was funded by several European government and industry grants.
Bonati disclosed serving on scientific advisory boards for Bayer.

• Reviewed by F. Perry Wilson, MD, MSCE Assistant Professor, Section of Nephrology, Yale School of Medicine and Dorothy Caputo, MA, BSN, RN, Nurse Planner

• Primary Source

  Stroke

  Source Reference: Müller MD, et al "Vascular anatomy predicts the risk of cerebral ischemia in patients randomized to carotid stenting versus endarterectomy" Stroke 2017; DOI: 10.1161/STROKEAHA.116.014612.