Over time, dealing with thromboembolic complications related to neuroendovascular procedures, since the first detachable stent was introduced in 1991, has remained a challenge . Finding more potent antiplatelet medications could make these procedures much safer and allow neurointerventionalists to use longer stents with confidence. Routinely, aspirin plus clopidogrel as DAPT has been used for prevention. However, a previous study indicated that antiplatelet resistance of clopidogrel might be related to TE [14-16]. The effectiveness of ticagrelor in preventing thromboembolic complications of endovascular procedures has been proven in coronary disease patients [18-20]. Therefore, ticagrelor might be an alternative prophylactic medication and we hope it can replace clopidogrel. To the best of our knowledge, the use of ticagrelor in neurovascular procedures was first published in 2014. Hanel et al. prescribed ticagrelor for 18 patients who were non-responders to clopidogrel and underwent neurointervention. All patients showed immediate platelet inhibition after a loading dose of 180 mg of ticagrelor, with no adverse effects. Ticagrelor offers an effective alternative to clopidogrel non-responders . Narata et al. published a retrospective single-center study of 154 consecutive patients with unruptured aneurysms in 2019. This study compared aspirin plus ticagrelor between flow diverter and stent-assisted coiling. In total, 41 patients underwent stent-assisted coiling. Nine patients (5.8%) presented with symptomatic neurological complications post-stenting (3 ischemic, 6 hemorrhagic) . According to these two studies, ticagrelor has adequate potency to prevent TE in SACE and is not inferior to clopidogrel. It may be a safer alternative option if the patient has a poor response to clopidogrel, but the number of cases remains small.
In the current study, platelet function test is no statistical differences between two groups according to preoperative laboratory data. On the other hands, the P2Y12 reaction unit value and Ticagrelor prescription were not routinely checked covered in guideline and also not covered by national health insurance which cause socioeconomic burden. Therefore, it’s difficult to set the randomize control grouping to choose patients who have received Ticagrelor protocol. However, Ticagrelor was prescribed in the patients who have risk factors of TE in the current study. Risk factors of TE after neuro-intervention of UIA were proposed and well explained in the several studies. In patient’s demography and past history, TE occurred more frequently in patients with vascular status associated with old age, diabetes, dyslipidemia and previous stroke. In characteristics of aneurysms, increased TE were noted when manage wide-neck and/or large aneurysms may be due to complex techniques and longer procedure time. Based on aforementioned evidence-based factors, we made the decision to have chosen patients who have received ticagrelor protocol in current study. Besides, the patients with previous allergy history of Clopidogrel were prescribed Ticagrelor.
As for the results of hemorrhagic events and adverse events, we used minor bleeding events to describe ecchymosis, epistaxis, or hemorrhoids. However, some patients complained of gastralgia, constipation, nausea/vomiting, or dizziness. In our opinion, those seen as adverse events were related to antiplatelet usage and affected patient compliance. For a further evaluation of the TE associated with dual antiplatelet therapy in SACE, we conducted a literature review. We searched PubMed using the terms “stent-assisted coil embolization and intracranial aneurysm”. We limited our search to articles published from January 1, 2013 to December 31, 2019. In total, 21 studies (shown in Table 4) were selected for the analysis [7-9, 12, 21, 23-37]. Studies with ruptured aneurysms or endovascular procedures without stenting were excluded. Aspirin plus clopidogrel was used in most of the studies (20 studies, 95.2%). Two studies used ticagrelor and three studies used prasugrel. In total, TE rates ranged from 0 to 22.22% in SACE, with an average of approximately 9.94%. Compared to our results, early thromboembolic event rates were 2.65%. Our findings revealed good results, but still fell within the average range of previously published papers. In the limited literature, the rate of ischemic stroke after ticagrelor therapy was only 0–1.9% (excluding the flow diverter). Although there is no statistical significance between clopidogrel and ticagrelor, ticagrelor may tend to have stronger potency in terms of reducing acute TE when compared with clopidogrel. This trend was also observed in other studies. On the other hand, there are some disadvantages regarding the clinical use of ticagrelor, including the cost of medication and patient compliance (for twice a day doses) .
This study has some limitations. First, there are relatively fewer cases in the cohort study, since the effect of other variables may have been underestimated. In the comparison of these two groups, there are much fewer cases in the ticagrelor group. Otherwise because of the clinically lower thromboembolic risk, the P2Y12 reaction unit value was not routinely checked and covered by national health insurance. Therefore, the true percentage of clopidogrel resistance was unknown. In order to create clinical guidelines, a prospective randomized controlled study is warranted to prove the effectiveness and safety of clopidogrel and ticagrelor.