Oral antiplatelet therapy and percutaneous coronary intervention

Treatment of intracranial arterial stenosis

Intracranial stenosis accounts for 8-10% of ischemic strokes in the USA. Treatment of intracranial stenosis with extracranial-to-intracranial bypass surgery was investigated as a therapy in the 1980s, but was shown to be no better than aspirin alone. The Warfarin vs Aspirin for Symptomatic Intracranial Disease study found a 12% per year risk of recurrent stroke for symptomatic lesions of 50% or higher, with the majority of strokes occurring in the first year. Warfarin was no better than aspirin in the prevention of recurrent stroke and had a higher risk of serious bleeding and death. Subgroup analysis showed that patients with the highest risk of recurrent stroke included those with 70% or more stenosis and/or recent symptoms and women. Angioplasty and stenting of intracranial stenosis have been undergoing rapid evolution in technology and are emerging as a promising therapy. Current treatment recommendations include antiplatelet agents, with consideration for angioplasty alone or angioplasty and stenting in cases refractory to medical therapy.

Dual antiplatelet therapy monitoring for neurointerventional procedures using a point-of-care platelet function test: a single-center experience

BACKGROUND AND PURPOSE

Growing evidence of the relationship between poor antiplatelet response and occurrence of clinical events elicited the need of monitoring the response which has not been part of our daily practice. We present our initial experience with a new point-of-care antiplatelet-function test (VerifyNow assay) in neurointerventional procedures.

MATERIALS AND METHODS

Among the 106 consecutive patients from July 2006 to April 2007, ninety-eight met the inclusion criteria. Our preferred antiplatelet regimen was aspirin (325 mg daily) and clopidogrel (300 mg of loading dose followed by 75 mg daily) starting 5-10 days before the procedure. The test results were reported as aspirin-reaction unit (ARU) for aspirin and P2Y(12) reaction units (PRU), baseline (BASE), and percentage inhibition for the P2Y(12) assay and were summarized as mean +/- SD of the values. We analyzed the effects of several factors of poor clopidogrel response (<40% inhibition). The occurrence of thrombotic events was recorded.

RESULTS

The mean ARU of aspirin assays was 438.3 +/- 47.9 (range, 350-632), and the response was poor in 2 patients (2.1%). For clopidogrel, the mean of the BASE, PRU, and percentage inhibition was 356.8 +/- 56.3 (range, 234-495), 198.9 +/- 104.4 (range, 8-401), and 45.2 +/- 27.1% (range, 0-98), respectively. Forty-two patients (42.9%) showed poor response. Multivariate analysis showed greater body weight (81.9 Kg +/- 19.1 kg versus 69.9 +/- 15 kg) in the poor-response group. All 3 cases of intraprocedural thrombosis (3.1%) were observed only in the poor-response group.

CONCLUSION

We observed a high frequency of poor clopidogrel responses in the neurointerventional setting. Routine monitoring of the drug response would be helpful for the early identification of poor antiplatelet responders so that we may modify the regimen and/or treatment plan.