Thromboelastography (TEG) results are predictive of ischemic and hemorrhagic complications in patients with unruptured intracranial aneurysms treated with flow diversion

Antiplatelets and antithrombotics in neurointerventional procedures: Guideline update

BACKGROUND

Antiplatelet and antithrombotic medication management before, during, and after neurointerventional procedures has significant practice variation. This document updates and builds upon the 2014 Society of NeuroInterventional Surgery (SNIS) Guideline 'Platelet function inhibitor and platelet function testing in neurointerventional procedures', providing updates based on the treatment of specific pathologies and for patients with specific comorbidities.

METHODS

We performed a structured literature review of studies that have become available since the 2014 SNIS Guideline. We graded the quality of the evidence. Recommendations were arrived at through a consensus conference of the authors, then with additional input from the full SNIS Standards and Guidelines Committee and the SNIS Board of Directors.

RESULTS

The management of antiplatelet and antithrombotic agents before, during, and after endovascular neurointerventional procedures continues to evolve. The following recommendations were agreed on. (1) It is reasonable to resume anticoagulation after a neurointerventional procedure or major bleeding episode as soon as the thrombotic risk exceeds the bleeding risk in an individual patient (Class I, Level C-EO). (2) Platelet testing can be useful to guide local practice, and specific approaches to using the numbers demonstrate marked local variability (Class IIa, Level B-NR). (3) For patients without comorbidities undergoing brain aneurysm treatment, there are no additional considerations for medication choice beyond the thrombotic risks of the catheterization procedure and aneurysm treatment devices (Class IIa, Level B-NR). (4) For patients undergoing neurointerventional brain aneurysm treatment who have had cardiac stents placed within the last 6-12 months, dual antiplatelet therapy (DAPT) is recommended (Class I, Level B-NR). (5) For patients being evaluated for neurointeventional brain aneurysm treatment who had venous thrombosis more than 3 months prior, discontinuation of oral anticoagulation (OAC) or vitamin K antagonists should be considered as weighed against the risk of delaying aneurysm treatment. For venous thrombosis less than 3 months in the past, delay of the neurointerventional procedure should be considered. If this is not possible, see atrial fibrillation recommendations (Class IIb, Level C-LD). (6) For patients with atrial fibrillation receiving OAC and in need of a neurointerventional procedure, the duration of TAT (triple antiplatelet/anticoagulation therapy=OAC plus DAPT) should be kept as short as possible or avoided in favor of OAC plus single antiplatelet therapy (SAPT) based on the individual's ischemic and bleeding risk profile (Class IIa, Level B-NR). (7) For patients with unruptured brain arteriovenous malformations there is no indication to change antiplatelet or anticoagulant management instituted for management of another disease (Class IIb, Level C-LD). (8) Patients with symptomatic intracranial atherosclerotic disease (ICAD) should continue DAPT following neurointerventional treatment for secondary stroke prevention (Class IIa, Level B-NR). (9) Following neurointerventional treatment for ICAD, DAPT should be continued for at least 3 months. In the absence of new stroke or transient ischemic attack symptoms, reversion to SAPT can be considered based on an individual patient's risk of hemorrhage versus ischemia (Class IIb, Level C-LD). (10) Patients undergoing carotid artery stenting (CAS) should receive DAPT before and for at least 3 months following their procedure (Class IIa, Level B-R). (11) In patients undergoing CAS during emergent large vessel occlusion ischemic stroke treatment, it may be reasonable to administer a loading dose of intravenous or oral glycoprotein IIb/IIIa or P2Y12 inhibitor followed by maintenance intravenous infusion or oral dosing to prevent stent thrombosis whether or not the patient has received thrombolytic therapy (Class IIb, C-LD). (12) For patients with cerebral venous sinus thrombosis, anticoagulation with heparin is front-line therapy; endovascular therapy may be considered particularly in cases of clinical deterioration despite medical therapy (Class IIa, Level B-R).

CONCLUSIONS

Although the quality of evidence is lower than for coronary interventions due to a lower number of patients and procedures, neurointerventional antiplatelet and antithrombotic management shares several themes. Prospective and randomized studies are needed to strengthen the data supporting these recommendations.

Periprocedural cerebrovascular complications and 30-day outcomes of endovascular treatment for intracranial vertebral artery dissecting aneurysms

OBJECTIVE

The authors undertook an evaluation of periprocedural cerebrovascular complications and 30-day outcomes of endovascular treatment for intracranial vertebral artery dissecting aneurysms (IVADAs) and assessed the relevant risk factors.

METHODS

The authors included a series of 195 patients who had undergone endovascular treatment for 198 IVADAs. Clinical data, morphological characteristics, treatment details, and periprocedural cerebrovascular complications including intraprocedural rupture, intraprocedural thrombosis, intracranial hemorrhage (ICH), transient ischemic attack (TIA), and ischemic stroke (IS) were recorded. After evaluation of the 30-day modified Rankin Scale (mRS) scores, the authors applied univariate and multivariate logistic regression analyses to identify the risk factors for complications and 30-day unfavorable clinical outcomes.

RESULTS

There were no intraprocedural ruptures, but the authors recorded intraprocedural thrombosis (n = 5), ICH (n = 3), TIA (n = 1), and IS (n = 13), comprising an 11.1% (22/198) complication rate. Multivariate logistic regression analysis indicated that hyperlipidemia (odds ratio [OR] 3.17, 95% confidence interval [CI] 1.20-8.41, p = 0.020), IS history (OR 5.55, 95% CI 1.46-21.01, p = 0.012), and subarachnoid hemorrhage (SAH) (OR 4.48, 95% CI 1.52-13.20, p = 0.007) were risk factors for overall complications, whereas aneurysmal height (OR 0.77, 95% CI 0.61-0.98, p = 0.032) was a protective factor. SAH (OR 6.44, 95% CI 1.54-26.89, p = 0.011) and preprocedural mRS score > 2 (OR 5.07, 95% CI 1.01-25.59, p = 0.049) were independent risk factors for perforator occlusion stroke. Periprocedural cerebrovascular complications (OR 32.09, 95% CI 3.00-343.94, p = 0.004) and preprocedural mRS score > 2 (OR 319.92, 95% CI 30.28-3379.98, p < 0.001) were independent risk factors for 30-day unfavorable clinical outcomes.

CONCLUSIONS

Hyperlipidemia, IS history, and SAH were independent predictors for overall periprocedural cerebrovascular complications of endovascular treatment for IVADAs, but aneurysmal height was an independent protective factor. SAH and preprocedural mRS score > 2 were independent risk factors for perforator occlusion stroke. Preprocedural mRS score > 2 and periprocedural complications were independent risk factors for 30-day unfavorable clinical outcomes.

Thromboelastography in the Perioperative Period: A Literature Review

Assessing coagulation status is essential for prompt intervention to reduce morbidity and mortality related to bleeding and thrombotic complications during the perioperative period. Traditional coagulation tests such as platelet count, activated partial thromboplastin time (aPTT), prothrombin time (PT), international normalized ratio (INR), and activated clotting time (ACT) provide only static evaluation. These tests are not designed for assessment of dynamically changing coagulation conditions during the perioperative time. However, viscoelastic coagulation testing such as thromboelastography (TEG) produces a rapid numerical and graphical representation that helps to detect and direct targeted hemostatic therapy. Searching the literature through PubMed, Medline, Ovid, CINAHL, and ClinicalTrials.gov we retrieved 210 studies, which represent the use of TEG in the perioperative period. The included studies were categorized under various settings such as trauma, obstetrics, orthopedics, intensive care unit (ICU), cardiovascular, transplant, and miscellaneous scenarios. TEG showed promising results in trauma surgeries in predicting mortality, hypercoagulability, and bleeding even when it was compared to conventional methods. TEG was also useful in monitoring anticoagulant therapy in orthopedic and obstetric surgeries; however, its role in predicting thrombotic events, hypercoagulability, or complications was questionable. In ICU patients, it showed promising results, especially in the prediction or improvement of sepsis, coagulopathy, thrombotic events, ICU duration, hospital stay, and ventilator duration. TEG parameters effectively predicted hypercoagulation in transplant surgeries. Regarding cardiovascular surgeries, they were effective in the prediction of the need for blood products, coagulopathy, thrombotic events, and monitoring anticoagulation therapy. More randomized clinical trials comparing TEG parameters with standardized tools are needed to produce robust results to standardize its use in different perioperative settings.

Excessive platelet inhibition following Pipeline embolization of intracranial aneurysms

BACKGROUND

High levels of platelet inhibition have been associated with hemorrhagic complications following Pipeline embolization of intracranial aneurysms. We therefore titrate clopidogrel dosing to maintain a moderate level of platelet inhibition using the VerifyNow P2Y12 assay. However, many patients demonstrate dramatic increases in platelet inhibition following treatment despite being on a consistent antiplatelet regimen. We therefore elected to explore the incidence of this phenomenon and possible predisposing factors.

METHODS

All successful Pipeline aneurysm treatments performed at our institution from 2011 to 2019 with moderate procedure-day platelet inhibition levels as indicated by a VerifyNow PRU of 60-235 were included. Patients who received glycoprotein IIb/IIIa inhibitors and those treated for ruptured/symptomatic lesions were excluded. The incidence of excessive platelet inhibition defined by a PRU<60 within 8 weeks of treatment was noted. Multivariable logistic regression was performed to determined independent predictors of the phenomenon.

RESULTS

Some 190 treatments were performed in 178 qualifying patients. A post-procedure PRU <60 occurred following 79% of treatments, documented on average after 8.5 (range 1-47) days. A higher procedure day hematocrit level (P=0.003, OR 1.09, 95% CI 1.029 to 1.152) was an independent predictor of reaching a PRU <60, while intra-procedural midazolam exposure (P=0.044, OR 0.44, 95% CI 0.201 to 0.980) and a higher procedure-day PRU (P=0.047, OR 0.99, 95% CI 0.982 to 1.000) were associated with a reduced odds. Time-since-procedure and hematocrit levels were associated with excessive platelet inhibition when excluding patients who initially demonstrated hyperresponse.

CONCLUSION

Elevations in platelet inhibition were frequently observed following flow diversion with Pipeline.