Aspirin irreversibly inhibits cyclooxygenase, preventing synthesis of vascular prostacyclin (a vasodilator and platelet inhibitor) and platelet thromboxane A2 (a vasoconstrictor and platelet activator). Platelets, lacking cellular organelles, cannot resynthesize cyclooxygenase, whereas the vascular tissues do so

NB: < 1000 mg ASA per day probably does not help with high-grade stenosis where there is rapid perfusion failure or flow failure. Some (but not all) studies show less effective in women, no large study has shown that ASA prevents a second stroke in patients that have already had one.

℞: For angina, a bolus dose of 160–325 mg PO is followed by maintenance doses of 80–160 mg/d (lower doses appear to be as effective as higher doses). Optimal doses continue for cerebrovascular ischemia continues to be debated. 325 mg PO q d reduces the risk of stroke following TIA by 25–30%. Daily doses of 81 or 325 mg, when compared to higher doses, were associated with a lower rate of stroke, MI, and death (6.2% vs. 8.4%) following carotid endarterectomy.

Acetylsalicylic acid (ASA) irreversibly blocks the platelet cyclo-oxygenase enzyme system, preventing formation of thromboxane A2 and inhibiting platelet aggregation for the life of the affected platelet (approximately 10 days).

This block occurs even at the lowest therapeutic/prophylactic ASA dose usually prescribed, 81 mg/day (10%/24 h). Because the ASA effect on individual platelets is complete, it cannot be reversed.

Based upon the customary rate of platelet production, approximately 5–6 days are required after cessation of ASA to replace approximately 50% of the circulating platelets

Aspirin is increasingly prescribed for its antithrombotic properties and usually recommended indefinitely following stent placement to prevent stent thrombosis.

Perioperative low dose use was not associated with increased risk of perioperative complications 1).

Aspirin increased the risk of rehaemorrhagia after surgery of hypertensive cerebral hemorrhage (HCH) 2).

Preinjury use of warfarin, but not antiplatelet medications, influences survival and need for neurosurgical intervention in elderly TBI patients with intracranial hemorrhage; hemorrhage progression and morbidity are not affected. The importance of antithrombotic therapy may lie in its impact on initial injury severity 3).

Periprocedural intravenous aspirin and unfractionated heparin during Endovascular treatment for acute ischemic stroke are both associated with an increased risk of symptomatic intracranial hemorrhage without evidence for a beneficial effect on functional outcome 4).

Various medicamentous methods of counteracting aspirin-induced platelet dysfunction and excessive bleeding in this context are revaluated. In this context, platelet infusion and the administration of Desmopressin seems to be an effective and accepted as well as frequently adopted measure to antagonize the aspirin effect on platelet function during various major surgical procedures 5)

Rahman M, Donnangelo LL, Neal D, Mogali K, Decker M, Ahmed MM. Effects of perioperative acetyl salicylic acid (ASA) on clinical outcomes in patients undergoing craniotomy for brain tumor. World Neurosurg. 2015 Feb 26. pii: S1878-8750(15)00122-9. doi: 10.1016/j.wneu.2015.02.016. [Epub ahead of print] PubMed PMID: 25727304.
Chen T, Xu G, Tan D, Wu C. Effects of platelet infusion, anticoagulant and other risk factors on the rehaemorrhagia after surgery of hypertensive cerebral hemorrhage. Eur Rev Med Pharmacol Sci. 2015 Mar;19(5):795-9. PubMed PMID: 25807432.
Grandhi R, Harrison G, Voronovich Z, Bauer J, Chen SH, Nicholas D, Alarcon LH, Okonkwo DO. Preinjury warfarin, but not antiplatelet medications, increases mortality in elderly traumatic brain injury patients. J Trauma Acute Care Surg. 2015 Mar;78(3):614-21. doi: 10.1097/TA.0000000000000542. PubMed PMID: 25710435.
van der Steen W, van de Graaf RA, Chalos V, Lingsma HF, van Doormaal PJ, Coutinho JM, Emmer BJ, de Ridder I, van Zwam W, van der Worp HB, van der Schaaf I, Gons RAR, Yo LSF, Boiten J, van den Wijngaard I, Hofmeijer J, Martens J, Schonewille W, Vos JA, Tuladhar AM, de Laat KF, van Hasselt B, Remmers M, Vos D, Rozeman A, Elgersma O, Uyttenboogaart M, Bokkers RPH, van Tuijl J, Boukrab I, van den Berg R, Beenen LFM, Roosendaal SD, Postma AA, Krietemeijer M, Lycklama G, Meijer FJA, Hammer S, van der Hoorn A, Yoo AJ, Gerrits D, Truijman MTB, Zinkstok S, Koudstaal PJ, Manschot S, Kerkhoff H, Nieboer D, Berkhemer O, Wolff L, van der Sluijs PM, van Voorst H, Tolhuisen M, Roos YBWEM, Majoie CBLM, Staals J, van Oostenbrugge RJ, Jenniskens SFM, van Dijk LC, den Hertog HM, van Es ACGM, van der Lugt A, Dippel DWJ, Roozenbeek B; MR CLEAN-MED investigators. Safety and efficacy of aspirin, unfractionated heparin, both, or neither during endovascular stroke treatment (MR CLEAN-MED): an open-label, multicentre, randomised controlled trial. Lancet. 2022 Feb 28:S0140-6736(22)00014-9. doi: 10.1016/S0140-6736(22)00014-9. Epub ahead of print. PMID: 35240044.
Korinth MC, Gilsbach JM, Weinzierl MR. Low-dose aspirin before spinal surgery: results of a survey among neurosurgeons in Germany. Eur Spine J. 2007 Mar;16(3):365-72. Epub 2006 Sep 5. PubMed PMID: 16953446; PubMed Central PMCID: PMC2200713.
  • aspirin.txt
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