Antiplatelet Drugs for Neurointerventions: Part 1 Clinical Pharmacology

Prasugrel Single Antiplatelet Therapy versus Aspirin and Clopidogrel Dual Antiplatelet Therapy for Flow Diverter Treatment for Cerebral Aneurysms: A Retrospective Multicenter Study

BACKGROUND AND PURPOSE

The optimal antiplatelet regimen after flow diverter treatment of cerebral aneurysms is still a matter of debate. A single antiplatelet therapy might be advantageous in determined clinical scenarios. This study evaluated the efficacy and safety of prasugrel single antiplatelet therapy versus aspirin and clopidogrel dual antiplatelet therapy.

MATERIALS AND METHODS

We performed a post hoc analysis of 4 retrospective multicenter studies including ruptured and unruptured aneurysms treated with flow diversion using either prasugrel single antiplatelet therapy or dual antiplatelet therapy. Primary end points were the occurrence of any kind of procedure- or device-related thromboembolic complications and complete aneurysm occlusion at the latest radiologic follow-up (mean, 18 months). Dichotomized comparisons of outcomes were performed between single antiplatelet therapy and dual antiplatelet therapy. Additionally, the influence of various patient- and aneurysm-related variables on the occurrence of thromboembolic complications was investigated using multivariable backward logistic regression.

RESULTS

A total of 222 patients with 251 aneurysms were included, 90 (40.5%) in the single antiplatelet therapy and 132 (59.5%) in the dual antiplatelet therapy group. The primary outcome-procedure- or device-related thromboembolic complications-occurred in 6 patients (6.6%) of the single antiplatelet therapy and in 12 patients (9.0%) of the dual antiplatelet therapy group (P = .62; OR, 0.712; 95% CI, 0.260-1.930). The primary treatment efficacy end point was reached in 82 patients (80.4%) of the single antiplatelet therapy and in 115 patients (78.2%) of the dual antiplatelet therapy group (P = .752; OR, 1.141; 95% CI, 0.599-2.101). Logistic regression showed that non-surface-modified flow diverters (P = .014) and fusiform aneurysm morphology (P = .004) significantly increased the probability of thromboembolic complications.

CONCLUSIONS

Prasugrel single antiplatelet therapy after flow diverter treatment may be as safe and effective as dual antiplatelet therapy and could, therefore, be a valid alternative in selected patients. Further prospective comparative studies are required to validate our findings.

Safety Profile and Complication Rates in Emergency Off-label Use of Tirofiban in Interventional Neuroradiology : An Observational Dual Center Study

PURPOSE

Tirofiban has been approved for the treatment of acute coronary syndrome. Meanwhile, tirofiban is frequently applied in emergency situations in interventional neuroradiology (INR). The objective of this study was to analyze the risk profile for the off-label use of tirofiban in INR patients.

METHODS

Data of 86 patients, who underwent neurointerventional therapy and were treated with tirofiban at 2 neuroendovascular centers between January 2016 and July 2017 were retrospectively analyzed. Despite off-label use, recent stroke (< 30 days), recent hemorrhage, thrombocytopenia (< 150,000/µl), activated partial thromboplastin time (aPTT) > 1.3-fold, internation normalised ratio (INR) < 1.5, severe liver insufficiency (Child-Pugh C), and preceding intravenous thrombolysis were considered as contraindications.

RESULTS

Median patient age was 62 years (range 26-88 years). Patients received tirofiban for extracranial (n = 35) or intracranial stenting (n = 35), coiling of ruptured cerebral aneurysms (n = 6), continuous intra-arterial nimodipine infusion via microcatheters for subarachnoid hemorrhage (SAH)-related vasospasm (n = 5), or thrombotic complications during neuroendovascular procedures (n = 5). The desired effect of preventing thrombotic complications when applying tirofiban off-label was achieved in 81 of 86 patients (94.2%). Relevant tirofiban-associated complications occurred in 14 patients (16.3%), of which 9 patients received i.v. thrombolysis for treatment of acute ischemic stroke shortly before starting therapy with tirofiban. Of the 86 patients 12 died, while the overall tirofiban-related mortality was 2.3% (2 patients died due to ICH). Logistic regression analysis revealed age to be the only parameter significantly associated with development of tirofiban-associated complications (p = 0.026).

CONCLUSION

Whereas the safety profile of tirofiban when applied off-label in INR is acceptable, the highest risk for relevant tirofiban-associated complications is observed in older patients treated by emergency stenting for acute stroke.

Antiplatelet Drugs for Neurointerventions: Part 2 Clinical Applications

Endovascular techniques have expanded to include balloon and stent-assistance, flow diversion and individualized endovascular occlusion devices, to widen the treatment spectrum for more complex aneurysm morphologies. While usually well-tolerated by patients, endovascular treatment of intracranial aneurysms carries the risk of complications, with procedure-related ischemic complications being the most common. Several antiplatelet agents have been studied in a neurointerventional setting for both prophylaxis and in the setting of intraprocedural thrombotic complications. Knowledge of these antiplatelet agents, evidence for their use and common dosages is important for the practicing neurointerventionist to ensure the proper application of these agents.Part one of this two-part review focused on basic platelet physiology, pharmacology of common antiplatelet medications and future directions and therapies. Part two focuses on clinical applications and evidence based therapeutic regimens.

Clinical Use of Cangrelor After Percutaneous Coronary Intervention in Patients Requiring Mechanical Circulatory Support

BACKGROUND

Patients with cardiogenic shock after percutaneous coronary intervention (PCI) may require mechanical circulatory support (MCS). The combination of dual antiplatelet therapy with cangrelor and continuous anticoagulation required for MCS may increase the risk of bleeding.

OBJECTIVE

The objective of the study is to describe the complications and outcomes of patients who received cangrelor during MCS following PCI.

METHODS

This is a single-center, retrospective, observational case series of 17 patients who received cangrelor while on MCS from June 2017 to September 2019.

RESULTS

In a case series of 17 patients, 8 patients (47%) were supported with an Impella device and 4 patients (24%) with venoarterial (VA) extracorporeal membrane oxygenation (ECMO); 5 required (29%) concomitant VA ECMO and Impella support in the setting of cardiogenic shock. All patients received triple antithrombotic therapy with aspirin, heparin, and cangrelor. Cangrelor was commonly initiated at a median dose of 0.75 (range 0.5-4) µg/kg/min. Cangrelor dose adjustments included changes in increments up to 0.25 µg/kg/min with review of P2Y12 levels. A total of 10 patients (59%) experienced a bleeding event, most commonly located at the peripheral cannulation site (40%) and in the gastrointestinal tract (30%). Seven (70%) and 3 (30%) of the bleeding complications were classified as major and minor, respectively. No patient developed in-stent thrombosis during the hospitalization; 14 (82%) patients survived their MCS course.

CONCLUSION AND RELEVANCE

This case series suggests that cangrelor doses less than 0.75 µg/kg/min may be beneficial. Larger studies should evaluate alternative dosing regimens.