Perioperative risk reduction and B-blockers. Topics. Introduction 3/26/2012

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1 Perioperative risk reduction and B-blockers UCSF Department of Surgery Postgraduate Course John Maa MD, FACS March 25, 2012 Topics 1) The controversy over beta blockers and POISE --- is Clonidine the answer? 2) Anticoagulants---bleeding versus thrombosis 3) Plavix - Coated and bare metal stents 4) When to stop bridging Lovenox? 5) Pradaxa Introduction Worldwide, about 100 million adults undergo non-cardiac surgery every year. Non-cardiac surgery is associated with major cardiovascular complications and over 1 million patients are likely to have such a complication every year. 1

2 Come in the water s fine 1995 to 2005 Early data high efficacy, low risk Treading water 2005 to

3 Equivocal data from randomized studies Everybody out of the pool! 3

4 Perioperative ischemic evaluation (POISE) trial A post POISE world Poise and balance Better results have been reported in the Netherlands Dr. Auerbach was one of the lead authors of a study in 2002 in NEJM that catalyzed the B- blocker wave 4

5 Clonidine for ischemic risk reduction and as anxiolytic Warfarin anticoagulation Invasive surgery is generally safe (from major hemorrhagic complication) when the INR < 1.5. It takes approximately 4 days for the INR to reach 1.5 once warfarin is stopped preoperatively. It takes approximately 3 days for the INR to reach 2.0 once warfarin is restarted postoperatively. All things considered, if warfarin is held 4 days pre-op and started immediately post-op, the patient is effectively without anticoagulation for 4 days (2 days preop and 2 days postop) Plavix 5

6 Dabigatran (Pradaxa in Australia, Europe and USA, Pradax in Canada, Prazaxa in Japan) is an oral anticoagulant from the class of the direct thrombin inhibitors. It is an alternative to warfarin as an orally administered anticoagulant that does not require frequent INR monitoring. There is no specific way to reverse the anticoagulant effect in the event of a major bleeding event. Study: Higher heart attack risk from pradaxa CBS News Jan 2012 Patients taking the Pradaxa have a 33% higher risk of heart attack or severe symptoms of heart disease than do patients taking warfarin. The finding in the Archives of Internal Medicine from the Cleveland Clinic is based on data from seven clinical trials that enrolled 30,514 patients. "The risk of MI or acute coronary syndrome is increased with Pradaxa compared with various control treatments, which include adjusteddose warfarin, Lovenox, or placebo. Pharmacokinetics of Pradaxa Pradaxa: about 80 % of the drug is excreted unchanged via the kidney. The remainder is excreted via the bile into the stool. In patients with normal renal function, Pradaxa s effect is mostly gone within 1-2 days after the last dose Pradaxa acts quickly: its maximum effect is reached within 2-3 hours of taking it. 6

7 When to stop Pradaxa before elective surgery For elective surgery, discontinue Pradaxa 2 days preop, but if there is reduced creatinine clearance and a high risk of bleeding stopping 5 days before may be necessary. No dietary restrictions are necessary Emergency surgery for a patient on Pradaxa Lab tests such as PT, INR, PTT and thrombin time are recommended, though they do not accurately reflect the bleeding risk or blood level of Pradaxa. Activated charcoal may be given if the drug was taken within two hours of arrival. FFP and vitamin K will not be of benefit as there is not a deficiency of clotting factors. Dialysis may be considered, but is likely impractical? The Skeptical Scalpel Nov 2011 As a last resort, recombinant activated Factor VII (rfviia) or prothrombin complex concentrate might be tried : Some have included rfviia or PCC as options to help with clot formation at the site of bleeding. They do not reverse the drug, the correct dose is unknown, and there is no FDA approval for this use. Thrombosis is a known side effect of rfviia and PCC. The half-life of Pradaxa is hours. For semi-emergency surgery such as appendectomy, it might be best to wait 12 hours to perform the surgery. 7