Mohammad Anadani, MD
Tandem occlusion, which includes cervical Internal Carotid Artery (ICA) severe stenosis/occlusion and intracranial occlusion, has been a challenge for decades. IV tPA, which was the only available acute stroke treatment before the thrombectomy era, achieves recanalization in as low as 4% of patients. After the publications of 5 randomized trials and subsequent meta-analysis (HERMES) showing the benefit of thrombectomy in large vessel occlusion including tandem occlusion, thrombectomy has become the standard of care for tandem occlusion. However, the best approach to the ICA stenosis/occlusion remained unclear. In tandem occlusion, there are generally three treatment options: thrombectomy alone, thrombectomy with ICA stenting, and thrombectomy with ICA angioplasty.
In this entry, I will discuss a recent publication by Panagiotis Papanagiotou and his colleagues regarding the best treatment approach for patients with tandem occlusion.
This was a large multicenter international study involving 18 centers. Patients who presented with tandem occlusion and received endovascular treatment were included. Tandem occlusion was defined as extracranial ICA lesion (complete occlusion or severe stenosis of ³90% by NASCET criteria, and a proximal intracranial occlusion (distal ICA, and/or M1, and/or M2). Patients were divided into 4 groups based on the ICA lesion treatment approach: group 1, acute stenting of the extracranial ICA lesion with antithrombotic agents; group 2, acute stenting without antithrombotic agents; group 3, balloon angioplasty of the extracranial ICA; group 4, no treatment of the extracranial ICA lesion. All groups received intracranial thrombectomy.
The primary endpoints were 90-day modified Rankin Scale (mRS), and modified Thrombolysis in Cerebral Infarction (mTICI) score at the end of procedure. mRS 0-2 was considered as a favorable outcome, and mTICI 2B -3 was considered as successful recanalization. Safety endpoints were symptomatic intracranial hemorrhage (sICH) at 24 hours and all-cause mortality at 90 days. sICH was defined based on ECASS criteria (ICH or intraventricular hemorrhage associated ³ 4 points increase of NIHSS).
A total of 482 patients were included in this study. Patients in group 1 had a better ASPECT score (8.2 vs. 7.2, p < 0.001) and lower admission NIHSS score (15 vs. 16.5, p =0.024) than group 4. Also, group 1 had a higher rate of general anesthesia used (54% vs 42%; p= 0.037) and shorter time from symptom onset to IV tPA (126.8 min vs 151.5 min, p < 0.001). Otherwise, there was no difference in baseline characteristics between all groups.
Comparison of functional outcome, complications, and recanalization rate between all treatment groups:
Group 1 had a higher rate of successful recanalization than group 4 (83% vs. 69%, p<0.001). Similarly, group 1 had a higher rate of successful recanalization than groups 2, 3, although the difference was not statistically significant.
Group 1 had a higher rate of favorable functional outcome (58% vs. 42%; p=0.007) when compared to group 4.
There was no statistically significant difference in outcome and mortality between group 1 and groups 2, 3.
Furthermore, the authors compared patients who received any cervical ICA procedure (groups 1-3) to those who received only intracranial MT (group 4) and found that patients who received ICA procedure had a higher rate of successful recanalization (mTICI 2B-3). The difference remained significant in adjusted model (odds ratio, 2.04; 95% confidence interval, 1.18-3.51). However, there was no difference in 90-day mRS, or mortality.
In a multivariate mixed logistic model, cervical ICA stenting with antithrombotic therapy was associated with recanalization, but not with favorable outcome (mRS 0-2) or mortality.
Comparison of functional outcome, complications, and recanalization rate based on antithrombotic therapy:
There was no difference in outcome, mortality, symptomatic ICH, or 90-day favorable outcome between patients who received one antithrombotic drug during procedure and those who received more than one.
The authors concluded that extracranial ICA with the use of antithrombotic agents in combination with MT was associated with favorable functional outcome, higher recanalization rate without an increased rate of hemorrhage.
Each of the treatment approaches has advantages and disadvantages. Cervical ICA stenting provides two main advantages: 1) treatment of the cervical ICA lesion, which ensures patency of the ICA; and 2) facilitate the passage of guidewire and subsequently the access to intracranial occlusion. These benefits come with a price. First, patients with ICA stent will require antithrombotic agents, which by itself increases the risk of systemic and intracranial hemorrhage, especially in the acute phase of stroke. Second, even though it is rare, ICA stent thrombosis could be a serious complication.
In conclusion, ICA stenting with antithrombotic medication is probably the best treatment approach for tandem occlusion.
Study limitations include retrospective, nonrandomized design and relatively small sample size of groups 3 and 4. Besides, the authors did not report the rate of stent thrombosis, which could account for the difference in the functional outcome between groups 1 and 2.
When deciding the treatment approach, one should take into account multiple factors, including pretreatment tPA and degree of stenosis (i.e., ICA stenosis vs. occlusion). Previous randomized trial1 showed that early initiation of aspirin increased the risk of sICH; therefore, the safety of stenting with antithrombotic therapy after tPA is still unclear. In addition, it is unclear if stent with antithrombotic agents is the best treatment of patients with nonocclusive ICA lesion.
References:
- Zinkstok, S. M., & Roos, Y. B. (2012). Early administration of aspirin in patients treated with alteplase for acute ischaemic stroke: a randomised controlled trial. The Lancet, 380(9843), 731-737.
