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Post-operative management of patients at high risk of MI with uninterrupted Clopidogrel therapy
- Dr Nathaniel M Broughton, Dr Louise Oduro, and Dr Nicholas Levy (3 December 2007)
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Blood transfusion and major cancer surgery
- William J Fawcett, Elizabeth L Combeer, Nial F Quiney (20 November 2007)
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Dr Nathaniel M Broughton, Anaesthetic ST2 West Suffolk Hospital, Dr Louise Oduro, and Dr Nicholas Levy
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Department of Anaesthesia & Intensive Care, West Suffolk Hospital, Hardwick Lane, Bury St.Edmunds, Suffolk. IP33 2QZ 28th November 2007 Dear Sir, We read with interest the review of perioperative antiplatelet therapy by Chassot and colleagues1. The case for continuing perioperative antiplatelet therapy in patients at high risk of myocardial infarction (MI) is clear. We certainly agree that during the first 3 months post insertion of a bare metal stent, or 12 months for drug eluting stents, only urgent surgery should be considered. We also agree that for most surgery undertaken during this period, dual antiplatelet therapy should be continued. However, we also believe that certain points require clarification. Where Clopidogrel is stopped preoperatively the risk of an ischaemic event is up to 45%2. In their recent review, Howard-Alpe advocate several days of postoperative high dependency monitoring should clopidogrel be stopped preoperatively3. This recommendation would cover patients during the period when they are at highest risk from either from a stent thrombosis MI or a non-vessel occlusion MI, which is at 24 and 36 hours respectively1,4. However, Chassot and colleagues make no recommendations regarding the level of postoperative care. Myocardial Infarction not only follows coronary artery occlusion but also when there is an imbalance between myocardial oxygen supply and demand (a non-vessel occlusion MI). We are concerned that increased surgical bleeding from uninterrupted dual agent therapy may increase the risk of a myocardial infarction from a non-vessel occlusion MI. This is a condition already under-diagnosed in the perioperative period. The signs of this condition include hypotension, anaemia, and tachycardia which should be readily recognised within a high dependency area, but this may not be so true for ward based care. We therefore suggest that all patients who are on a course of Clopidogrel, that are undergoing major surgery, irrespective of whether the drug has been stopped perioperatively, should be monitored within a high dependency area postoperatively for at least 48hours to allow early identification and prompt treatment of a perioperative MI. When stopped pre-operatively, Chassot and colleagues advise recommencing Clopidogrel at a 300mg loading dose1. Conversely, Howard-Alpe and colleagues3 suggest that a loading dose of 600mg will expedite the therapeutic effect. Local guidelines in this region do not comment upon postoperative loading5. It would appear that on this matter consensus opinion is yet to emerge. We believe that further consideration of the above points is essential before comprehensive guidelines can be adopted. Yours, Dr Nathaniel Broughton* Anaesthetic ST2 Dr Louise Oduro Anaesthetic ST1 Dr Nicholas Levy Consultant in Anaesthesia & Intensive Care *Author for correspondence References 1 – ‘Perioperative antiplatelet therapy: the case for continuing therapy in patients at risk of myocardial infarction’ Chassot et al. BJA 2007; 99: 316-328 2 – ‘Coronary artery stenting and non-cardiac surgery – a prospective outcome study’ Vicenzi et al. BJA 2006; 96: 686-693 3 – ‘Coronary artery stents and non-cardiac surgery’ Howard-Alpe et al. BJA 2007; 98: 560-574 4 – ‘Myocardial infarction after vascular surgery: the role of prolonged stress-induced, ST depression-type ischemia’. Landesberg G, Mosseri M, Zahger D, et al. J Am Coll Cardiol 2001; 37: 1839–45 5 – ‘Guidelines for Perioperative Cessation of Anticoagulant and Antiplatelet Agents Around Elective Non-Cardiac Surgery’ - Anglia Cardiac Network, May 2007 Conflict of Interest:None declared |
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William J Fawcett, Consultant anaesthetist Royal Surrey County Hospital, Guildford GU2 7XX. UK, Elizabeth L Combeer, Nial F Quiney
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We were interested to read the review by Chassot et al [1] of perioperative antiplatelet therapy. The review is both timely and well thought out. The authors present a well balanced assessment of the risks and benefits of per operative antiplatelet therapy. However we would like to challenge their assessment of the safety of blood transfusion during surgery. The authors state that the ‘complication rate of red blood cell transfusion is only 0.4% (all types of complications included) and a mortality linked to massive surgical blood loss is <3%’. The authors seemed to have ignored the very real effects of per operative allogenic red cell transfusion on long term survival in patients undergoing surgery for malignant tumours. For example the current evidence suggests that avoiding per operative transfusion of red blood cells during liver tumour resection for colorectal metastases leads to a doubling of 3 and 5 year survival [2]. As a result of this surgeons and anaesthetists involved in these operations have developed techniques to minimise [3, 4] and eventually avoid [5] blood transfusion during major liver resection surgery. Similar effects on survival have also been shown in patients undergoing colorectal tumour resection (). To dismiss this important deleterious effect of red blood cell transfusion would, in our view, be a mistake. Rather a review, for each patient, of the risks and benefits of antiplatelet therapy is probably the most sensible approach. References 1. Chassot P-G, Delabays A, Spahn DR. Perioperative antiplatelet therapy: the case for continuing therapy in patients at risk of myocardial infarction. British Journal of Anaesthesia 2007;99:316-28 2. Gozzetti G, Mazziotti A, Grazi GL, Jovine E, Gallucci A, Gruttadauria S, Frena A, Morganti M, Ercolani G, Masetti M, Pierangeli F. Liver resection without blood transfusion. British Journal of Surgery 1995;82:1105-10 3. Fawcett WJ Quiney NF, Karanjia ND. Liver resection and hypovolaemia: a technique vindicated. Anaesthesia 2006;61:82-3. 4. Quiney NF, Langford L, Patel A, Fawcett WJ. Blood loss and transfusion requirements during hepatic resection surgery under low CVP conditions - is routine cross-matching essential? European Journal of Anaesthesiology 2007; 24:70 5. Torzilli G, Gambetti A, Del Fabbro D, Leoni P, Olivari N, Donadon M, Montorsi M, Makuuchi M. Techniques for hepatectomies without blood transfusion, focusing on interpretation of postoperative anaemia. Archives of Surgery 2004:139;1061-5 Conflict of Interest:None declared |
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