Intentional Stent Stenosis to Prevent Hyperperfusion Syndrome after Carotid Artery Stenting for Extremely High-Grade Stenosis

Post-Carotid Artery Stenting Hyperperfusion Syndrome in a Hypotensive Patient: Case Report and Systematic Review of Literature

Cerebral hyperperfusion syndrome (CHS) is a serious post-procedural complication of carotid artery stenting (CAS). The pathophysiological mechanisms of CHS in the absence of arterial hypertension (AH) remain only partially understood. We performed a systematic literature search of the PubMed database using the terms »cerebral hyperperfusion syndrome«, »hypotension«, »hyperperfusion«, »stroke«, »intracranial hemorrhages«, »risk factors«, »carotid revascularization«, »carotid stenting«, »carotid endarterectomy«, »blood-brain barrier«, »endothelium«, »contrast encephalopathy«, and combinations. We present a case of a normotensive female patient who developed CHS post-CAS for symptomatic carotid stenosis while being hypotensive with complete recovery. We identified 393 papers, among which 65 were deemed relevant to the topic. The weighted average prevalence of CHS after CAS is 1.2% [0.0-37.7%] with that of intracranial hemorrhage (ICH) being 0.51% [0-9.3%]. Recently symptomatic carotid stenosis or contralateral carotid revascularization, urgent intervention, acute carotid occlusion, contralateral ≥70% stenosis, and the presence of leptomeningeal collaterals were associated with CHS. A prolonged hemodynamic instability after CAS conveys a higher risk for CHS. However, none of the articles mentioned isolated hypotension as a risk factor for CHS. Whereas mortality after ICH post-CAS ranges from 40 to 75%, in the absence of ICH, CHS generally carries a good prognosis. AH is not obligatory in CHS development. Even though impaired cerebral autoregulation and post-revascularization changes in cerebral hemodynamics seem to play a pivotal role in CHS pathophysiology, our case highlights the complexity of CHS, involving factors like endothelial dysfunction and sudden reperfusion. Further research is needed to refine diagnostic and management approaches for this condition.

Predictors and Outcomes of Periprocedural Intracranial Hemorrhage after Stenting for Symptomatic Intracranial Atherosclerotic Stenosis

BACKGROUND AND PURPOSE

Periprocedural intracranial hemorrhage is one of common complications after stent placement for symptomatic intracranial atherosclerotic stenosis. This study was conducted to demonstrate predictors and long-term outcomes of periprocedural intracranial hemorrhage after stent placement for symptomatic intracranial atherosclerotic stenosis.

MATERIALS AND METHODS

We retrospectively analyzed patients with symptomatic intracranial atherosclerotic stenosis stent placement in a prospective cohort at a high-volume stroke center. Clinical, radiologic, and periprocedural characteristics and long-term outcomes were reviewed. Periprocedural intracranial hemorrhage was classified as procedure-related hemorrhage (PRH) and non-procedure-related hemorrhage (NPRH). The long-term outcomes were compared between patients with PRH and NPRH, and the predictors of NPRH were explored.

RESULTS

Among 1849 patients, 24 (1.3%) had periprocedural intracranial hemorrhage, including PRH (4) and NPRH (20). The postprocedural 30-day mRS was 0-2 in 9 (37.5%) cases, 3-5 in 5 (20.8%) cases, and 6 in 10 (41.7%) cases. For the 14 survivors, the long-term (median of 78 months) mRS were 0-2 in 10 (76.9%) cases and 3-5 in 3 (23.1%) cases. The proportion of poor long-term outcomes (mRS ≥3) in patients with NPRH was significantly higher than those with PRH (68.4% versus 0%, P = .024). Anterior circulation (P = .002), high preprocedural stenosis rate (P < .001), and cerebral infarction within 30 days (P = .006) were independent predictors of NPRH after stent placement.

CONCLUSIONS

Patients with NPRH had worse outcomes than those with PRH after stent placement for symptomatic ICAS. Anterior circulation, severe preprocedural stenosis, and recent infarction are independent predictors of NPRH.

Gradual Expansion of a Stent to Prevent Periprocedural Complications after Carotid Artery Stenting for Vulnerable Severe Stenotic Lesions with Intraplaque Hemorrhages: A Retrospective Observational Study

Vulnerable lesions with intraplaque hemorrhages are associated with a high incidence of complications following carotid artery stenting (CAS). CAS for vulnerable lesions has not been established; therefore, we gradually expand stents in such patients. This study aimed to compare the incidences of complications between gradual-expansion CAS for vulnerable lesions and standard CAS for non-vulnerable lesions. For gradual-expansion CAS, we used 3.0 or 4.0 mm balloons for minimal luminal diameters (MLDs) <2.0 or ≥2.0 mm, respectively, for pre-stenting angioplasty (SA) and did not overinflate them. By contrast, for standard CAS, we used a 4.0 mm balloon and overinflated it to 4.23 mm. A closed-cell stent was deployed, and post-SA was not performed in both groups. We evaluated the MLD before and minimal stent diameter (MSD) immediately after CAS, as well as periprocedural complications of combined stroke, death, and myocardial infarction within 30 days after CAS. In the vulnerable and non-vulnerable groups, 30 and 38 patients were analyzed, the MLDs were 0.76 and 0.96 mm before CAS, the MSDs were 2.97 mm and 3.58 mm after CAS, and the numbers of complications were 0 and 1, respectively. Gradual-expansion CAS for vulnerable lesions was as safe as standard CAS for non-vulnerable lesions.

Reduced magnetic resonance angiography signal intensity in the middle cerebral artery ipsilateral to severe carotid stenosis may be a practical index of high oxygen extraction fraction

Objectives

Angiographic “slow flow” in the middle cerebral artery (MCA), caused by carotid stenosis, may be associated with high oxygen extraction fraction (OEF). If the MCA slow flow is associated with a reduced relative signal intensity (rSI) of the MCA on MR angiography, the reduced rSI may be associated with a high OEF. We investigated whether the MCA slow flow ipsilateral to carotid stenosis was associated with a high OEF and aimed to create a practical index to estimate the high OEF.

Methods

We included patients who underwent digital subtraction angiography (DSA) and MRA between 2015 and 2019 to evaluate carotid stenosis. MCA slow flow by image count using DSA, MCA rSI, minimal luminal diameter (MLD) of the carotid artery, carotid artery stenosis rate (CASr), and whole-brain OEF (wb-OEF) was evaluated. When MCA slow flow was associated with a high wb-OEF, the determinants of MCA slow flow were identified, and their association with high wb-OEF was evaluated.

Results

One hundred and twenty-seven patients met our inclusion criteria. Angiographic MCA slow flow was associated with high wb-OEF. We identified MCA rSI and MLD as determinants of angiographic MCA slow flow. The upper limits of MCA rSI and MLD for angiographic MCA slow flow were 0.89 and 1.06 mm, respectively. The wb-OEF was higher in patients with an MCA rSI ≤ 0.89 and ipsilateral MLD ≤ 1.06 mm than patients without this combination.

Conclusions

The combination of reduced MCA rSI and ipsilateral narrow MLD is a straightforward index of high wb-OEF.

Key Points

• The whole-brain OEF in patients with angiographic slow flow in the MCA ipsilateral to high-grade carotid stenosis was higher than in patients without it.

• Independent determinants of MCA slow flow were MCA relative signal intensity (rSI) on MRA or minimal luminal diameter (MLD) of the carotid stenosis.

• The wb-OEF was higher in patients with an MCA rSI ≤ 0.89 and ipsilateral MLD ≤ 1.06 mm than patients without this combination.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00330-021-08272-3.