XXIV World Congress of the International Union of Angiology April 21 - 25, 2010 Buonos Aires, Argentina
ANTI-PLATELET DRUGS: CORRELATION BETWEEN PLATELET FUNCTION AND PERIOPERATIVE BLOOD LOSS IN VASCULAR SURGERY Moniaci D*, Iazzolino L*, Renghi A**, Garavoglia M****, Bellomo G***, Pergolini P***, Brustia P* *S.C.D.O. di Chirurgia Vascolare, Ospedale ”Maggiore della Carità”, Novara **S.C.D.U. di Anestesia e Rianimazione I, Ospedale ”Maggiore della Carità”, Novara ***S.C.D.O. di Laboratorio di Analisi Chimico-Cliniche, Ospedale ”Maggiore della Carità”, Novara ****S.C.D.U. di Chirurgia Generale, Ospedale ”Maggiore della Carità”, Novara
Introduction Bridge Therapy 6 ANTIPLATELET THERAPY In the patient enrolled for Carotid Endarterectomy the anti platelet (AP) therapy must continue or has to be introduced in the Aspirin/ Combined ASA 100 mg perioperative period because of the protective effect played both dipyridamole: 5 Therapy 6 43 on the carotid postoperative thrombosis and on the coronary ASA 100 mg 1,2,3 complications . Some Authors even suggest the use of a combined AP therapy, ASA 200 mg 4 in order to further reduce the risk of postoperative thrombosis . Considering that the balance of an anti-platelet therapy is deThienopyridines licate and stands between a vascular event and the risk of surgical bleeding, the introduction of new tools for assessment of Aspirin/ platelet function (Aggregometry and PFA), may suggest impordipyridamole tant information to the surgeon, such as the identification of the Bridge Therapy patients with a perioperative high bleeding risk and the identification of the candidates for the carotid endarterectomy who Combined Therapy might undergo combined AP therapy (due to the weak effect of ASA 200 mg: 21 Thienopyridines: 28 a single therapy). Materials and Methods A prospective study about all the patients enrolled for Carotid CEA SURGICAL TECHNIQUE Endarterectomy between October 2008 and May 2009 at the “Vascular and Endovascular Surgery Division”, Novara aimed to evaluate the correlation between AP drug (type/dose), perioDirect carotid endarterectomy perative bleeding (on the basis of surgeon evaluation) and platelet data obtained by PFA and Aggregometry. Bypass Results Eversion technique 108 patients were enrolled: 59% were under acetylsalicylic acid therapy, 25% under thienopyridines therapy, 5% under aspirin/ Patch Angioplsty dipyridamole therapy, 6% under bridge therapy (the temporary perioperative substitution of low-molecular-weight heparin Patch Angioplsty or unfractionated heparin in place of warfarin) and 5% under Eversion technique combined therapy. Direct carotid endarterectomy Perioperative outcome: 3 out of 108 patients (2,8%) suffered from Bypass minor neurological accidents due to microembolizations, there were no hemorragic complication, no cardiac ischemic accidents. The PFA and Aggregometry data do not correlate with a longer bleeding time. No AP therapy caused haemostatic difficulties. In the patients with thromboembolic complications neither Aggregometry nor the surgeon’s opinions resulted predictive; we underline that in those patients the PFA data marked a resistance to the ASA therapy, but this ASA resistance was sensed also in other patients who had not had such consequences.
Conclusions
The first outcome of our study is that in CEA surgery AP therapies provide a successful protection against thromboembolic complications without increasing the bleeding time length. The PFA and Aggregometry data do not correlate with surgical bleeding time. 5,6 If the PFA data are in accordance with the literature , those concerning Aggregometry diverge from the literature which instead correlates Aggregometric data and thromboembolic/hemorragic complications. This can be caused by a sample of patients not 7 wide enough, as the complications mentioned above in the samples we studied are small . In order to evaluate the Aggregometric skills about clinical predictability we conclude that further studies on larger samples of pa8,9 tients are essential . Bibliography 1 Engelter S, Lyrer P. Antiplatelet therapy for preventing stroke and other vascular events after carotid endarterectomy. Stroke. 2004 May;35(5):1227-8. Epub 2004 Apr 1 2 Chassot PG, Delabays A, Spahn DR. Perioperative use of anti-platelet drugs. Best Pract Res Clin Anaesthesiol. 2007 Jun;21(2):241-56. 3 Grines CL, Bonow RO, Casey DE Jr, Gardner TJ, Lockhart PB, Moliterno DJ, O’Gara P, Whitlow P. Prevention of premature discontinuation of dual antiplatelet therapy in patients with coronary artery stents: a science advisory from the American Heart Association, American College of Cardiology, Society for Cardiovascular Angiography and Interventions, American College of Surgeons, and American Dental Association, with representation from the American College of Physicians. American Heart Association; American College of Cardiology; Society for Cardiovascular Angiography and Interventions; American College of Surgeons; American Dental Association; American College of Physicians. J Am Dent Assoc. 2007 May;138(5):652-5. 4 Payne DA, Jones CI, Hayes PD, Thompson MM, London NJ, Bell PR, Goodall AH, Naylor AR. Beneficial effects of clopidogrel combined with aspirin in reducing cerebral emboli in patients undergoing carotid endarterectomy. Circulation. 2004 Mar 30;109(12):1476-81. Epub 2004 Mar 8. 5 Gum PA, Kottke-Marchant K, Welsh PA, White J, Topol EJ: A prospective, blinded determination of the natural history of aspirin resistance among stable patients with cardiovascular disease. J Am Coll Cardiol 2003;41:961–965. 6 Chakroun T, Gerotziafas G, Robert F, Lecrubier C, Samama MM, Hatmi M, Elalamy I: In vitro aspirin resistance detected by PFA-100■ closure time: pivotal role of plasma von Willebrand factor. Br J Haematol 2004;124:80–85. 7 Casagrande JT, Pike MC, Smith PG: The power function of the ‘exact’ test for comparing two binomial distributions. Appl Stat 1978; 27: 176–80. 8 Karger R, Donner-Banzhoff N, Müller HH, Kretschmer V, Hunik M: Diagnostic performance of the platelet function analyzer (PFA-100) for the detection of disorders of primary haemostasis in patients with a bleeding history – a systemic review and metaanalysis. Platelets 2007;18:249–260. 9 Toth O, Calatzis A, Penz S, Losonczy H, Siess W: Multiple electrode aggregometry: a new device to measure platelet aggregation in whole blood. Thromb Haemost 2006;96:781–788.
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