Cardiac Issues With Non-cardiac Surgery and role of antiplatelets

and anticoagulantsDr Hiralal Pawar

• With progressive aging of the populations,the prevalence of coronary artery disease is increasing.

• Antiplatelet agents are prescribed widely for primary and secondary prevention of cardiovascular disease and especially after percutaneous coronary interventions (PCI)and acute coronary syndromes

• Currently ,over 90% of all PCI involve stents used for a variety of indications

• A rare but serious complications after coronary stent implantation is stent thrombosis

• Different factors are known to be independantly correlated with an increase risk of stent thrombosis including high risk lesions, small vessel lesions,bifurcations,DM ,renal failure

• Most important risk factor , however,is premature cessation of dual antiplatelet therapy with aspirin and thienopyridines

• Recent report suggest that 5% of post PCI patients requires non cardiac surgery within 1 year period

Objectives

• Preoperative risk assessment

• Antiplatelets

• Anticoagulation and antithrombotic issues

• Postoperative Management

• We have patients with following characteristics

• 1)Post ACS—STEMI,NSTEMI,UA

• 2)chronic stable angina

• 3)post PCI

• 4)post CABG

Preoperative cardiac issues

• How healthy is the patient?

• How active is the patient?

• How risky in the planned surgery?

• Is preoperative cardiac testing necessary?

• What preventive measures can be taken to reduce cardiac risk?

• In describing the temporal necessity of operations in this CPG, the GWC developed the following definitions by

• consensus. • An emergency procedure is one in which life or limb is

threatened if not in the operating room where there is time for no or very limited or minimal clinical evaluation, typically within <6 hours.

• An urgent procedure is one in which there may be time for a limited clinical evaluation, usually when life or limb is threatened if not in the operating room, typically between 6 and 24 hours.

• A time-sensitive procedure is one in which a delay of >1 to 6 weeks to allow for an evaluation and significant changes in management will negatively affect outcome

• Most oncologic procedures would fall into this category

•An elective procedure is one in which the procedure could be delayed for up to 1 year. Individual institutions may use slightly different definitions, but this framework could be mapped to local categories. •A low-risk procedure is one in which the combined surgical and patient characteristics predict a risk of a major adverse cardiac event (MACE) of death or myocardial infarction (MI) of <1%. Selected examples of low-risk procedures include cataract and plastic surgery .• Procedures with a risk of MACE of ≥1% are considered elevated risk.

L’Italien JACC 1996;27:779

JACC 2002; 39:542

JACC 2002 39:542

Who to test?

• Intermediate risk patients undergoing intermediate or high risk surgery

• Testing does not add additional information in low risk or high risk patient groups.

What test?

• Well validated– Exercise or

pharmacologic echocardiography

– Exercise or pharmacologic Cardiolite

– CTA

– MRI– Cardiac angiography*

Therapies to reduce perioperative cardiac complications

• Revascularization– Percutaneous revascularization– CABG

• Medical therapy

• The Coronary Artery Revascularization Prophylaxis (CARP) trial compared optimal medical therapy with revascularization (CABG or PCI) in patients with stable IHD before major non cardiac surgery.

• The results of the CARP study indicated that systematic

prophylactic revascularization before vascular surgery does not improve clinical outcomes in stable patients.

Timing of Elective Noncardiac Surgery in Patients With Previous PCI: ACC/AHA 2014

• Recommendations

• Class I

• 1. Elective noncardiac surgery should be delayed 14 days after balloon angioplasty (Level of Evidence: C) and 30 days after BMS implantation (Level of Evidence B).

• 2. Elective noncardiac surgery should optimally be delayed 365 days after drug-eluting stent (DES) implantation. (Level of Evidence: B)

• Antiplatelet Agents: Recommendations

• ACC/AHA 2014

• Class I

• 1. In patients undergoing urgent noncardiac surgery during the first 4 to 6 weeks after BMS or DES implantation, DAPT should be continued unless the relative risk of bleeding outweighs the benefit of the prevention of stent thrombosis. (Level of Evidence: C)

• 2. In patients who have received coronary stents and must undergo surgical procedures that mandate the discontinuation of P2Y12 platelet receptor–inhibitor therapy, it is recommended that aspirin be continued if possible and the P2Y12 platelet receptor–inhibitor be restarted as soon as possible after surgery. (Level of Evidence: C)

• 3. Management of the perioperative antiplatelet therapy should be determined by a consensus of the surgeon,anesthesiologist, cardiologist, and patient, who should weigh the relative risk of bleeding versus prevention of stent thrombosis. (Level of Evidence: C)

• Class IIb1. In patients undergoing nonemergency/nonurgent noncardiac surgery who have not had previouscoronary stenting, it may be reasonable to continue aspirin when the risk of potential increasedcardiac events outweighs the risk of increased bleeding (298, 306). (Level of Evidence: B)

ANTITHROMBOTICS

• Use of therapeutic or full-dose anticoagulants (as opposed to the lower-dose anticoagulation often used for prevention of deep venous thrombosis) is generally discouraged because of their harmful effect on the ability to control and contain surgical blood loss.

• Vitamin K antagonists (warfarin) are prescribed for stroke prevention in patients with AF, for prevention of thrombotic and thromboembolic complications in patients with prosthetic valves, and in patients requiring deep venous thrombosis prophylaxis and treatment.

• Factor Xa inhibitors are prescribed for prevention of stroke in the management of AF. Factor Xa inhibitors are not recommended for long-term anticoagulation of prosthetic valves because of an increased risk of thrombosis when compared with warfarin.

• The role of anticoagulants other than platelet inhibitors in the secondary prevention of myocardial ischemia or MI has not

• been elucidated.

Weighing the Risks

HEMORRHAGE

THROMBOSIS

•Venous

•5-10% fatal

•<5% disabling

•Arterial

•20-40% fatal

•20-50% disabling

•Major bleeding

•9-13% fatal

•Rarely disabling

• The risks of bleeding for any surgical procedure must be weighed against the benefit of remaining on anticoagulants on a case-by-case basis.

• In some instances in which there is minimal to no risk of bleeding, such as cataract surgery or minor dermatologic procedures, it may be reasonable to continue anticoagulation perioperatively.

Warfarin

• The most common indications for oral anticoagulant therapy are atrial fibrillation, the presence of a mechanical heart valve, and venous thromboembolism. Warfarin is the most common oral anticoagulant prescribed for the treatment and prophylaxis of venous or arterial thromboembolism in India.

• The mean half-life of warfarin activity is approximately 40 hours and the anticoagulant effect lasts 2–5 days.

• For most patients, the therapeutic target for the international normalised ratio (INR) range is 2.0–3.0.

• For patients with a mechanical heart valve, the recommended INR range is 2.5–3.5.

• When considering how to manage patients on warfarin who require surgery, it is helpful to weigh up the risk of bleeding versus the risk of thromboembolism (Table 1). This requires consideration of:

• ■ indication for anticoagulation• ■ history of any thrombotic events• ■ type of surgery and its associated risks of bleeding and

thromboembolism, particularly with respect to postoperative venous thromboembolism.

• The patient's management is guided by the risk of thromboembolism (Fig. 2). The options include:■ if low risk, stop warfarin five days before surgery (that is missing four doses before the day of surgery) to allow the INR to drop to less than 1.5, then resume it on the evening of the procedure if there is no evidence of bleeding

•■ if high risk, stop warfarin and start heparin (unfractionated heparin infusion or low molecular weight heparin) before and after the surgery, during the period when the INR is below the therapeutic range. This option is referred to as 'bridging‘ anticoagulation. Heparin is usually started on the third morning after the last dose of warfarin when the INR becomes subtherapeutic.

• Stopping heparin preoperatively• For patients who receive bridging anticoagulation with therapeutic

doses of low molecular weight heparin, the last dose should be administered at least 24 hours before the procedure. There is evidence suggesting that there will be a residual anticoagulant effect if low molecular weight heparin is given too close to the time of the procedure. It is recommended that the last preoperative dose be half the usual total daily dose.

• For unfractionated heparin, it is recommended that the infusion be stopped 4–6 hours before the procedure.

• Resuming heparin postoperatively• The factors that affect the risk of postoperative bleeding include the timing of the

anticoagulant dose after surgery, the dose of anticoagulant and the type of surgery along with its associated bleeding risk.The following recommendations take all of these factors into consideration:

• ■ warfarin can be resumed on the evening of the procedure (regardless of whether the procedure is performed in the morning or afternoon), at the usual maintenance dose (no loading dose)

• ■low molecular weight heparin or unfractionated heparin can be resumed 12–24 hours following the procedure for mminor surgery. For major surgery, the first dose should be 24–72 hours post surgery.9 The initial dose will vary from the prophylactic dose (for example, enoxaparin 40 mg daily) to the therapeutic dose (for example, enoxaparin 1 mg/kg twice daily) depending on the risk of thrombosis, and the risk of bleeding. This needs to be individualised for each patient

Other anticoagulant drugs

• There are an increasing number of patients participating in clinical trials that evaluate the efficacy and safety of other oral anticoagulants such as rivaroxaban and dabigatran for the treatment and prevention of venous and arterial thrombosis.

• Rivaroxaban, a direct factor Xa inhibitor, has a half-life of 4–9 hours. • Dabigatran has a longer half-life of 14–17 hours.• Bridging anticoagulation with a heparin can be used if indicated.• This can be started 24 hours after the last dose of rivaroxaban or

dabigatran.

• Factor Xa inhibitors do not have a reversible agent available at this time. For patients with AF and

• normal renal function undergoing elective procedures during which hemostatic control is essential, such as

• major surgery, spine surgery, and epidural catheterization, discontinuation of anticoagulants for ≥48 hours is

• suggested. Monitoring activated partial thromboplastin time for dabigatran and prothrombin time for apixaban

• and rivaroxaban may be helpful; a level consistent with control levels suggests a low serum concentration of the

• anticoagulant

Recommendations

• Revascularization for appropriate clinical indications

• Maximize adjuvant medical therapy– Aspirin– Statin– Beta blocker

• Close perioperative follow-up

Cardiac Issues in noncardiac surgery

• Establish patient risk

• Assign procedural risk

• Test intermediate risk patients undergoing intermediate or high risk surgery

• Optimize medical therapy

• Revascularization when clinically indicated

• ACC/AHA Guidelines

Anticoagulation / Antiplatelet Agents

• 55 year old male s/p CABG in 2000. Drug eluting stent placed to native vessel in August of 2008.

• Needs colonoscopy • Can plavix and aspirin

be safely stopped?

• 70 year old white female with chronic AF needs shoulder surgery

• History of CVA• Warfarin 5 mg daily• Does the patient need

some form of bridging preoperatively?

CHADS score - AF

Circulation 2004; 110:2287 JAMA 2001; 285:2864

Atrial fibrillation

• Bridge– AF and prosthetic

valves– AF and significant LV

dysfunction (EF<40%)– AF and any prior

thrombotic event (CVA, TIA, arterial emboli)

– “high risk” patients

• No bridging– Low risk patients

How to bridge

• Stop warfarin for 48 hours

• Start lovenox at 1mg/kg SQ BID for 6 doses

• Stop lovenox the morning before surgery

Prosthetic heart valves

• Bioprosthetic valves– All, if in atrial fibrillation

• Mechanical valves– All, regardless of rhythm

Venous thrombosis

• Deep venous thrombosis

• Pulmonary emboli

• Hypercoagulable states– Factor V Leiden– Protein C / S deficiencies– Lupus anticoagulant

How to Bridge

• Stop warfarin

• Start replacement therapy once INR < 2.0– IV heparin– SQ low molecular weight heparin - lovenox

Improved cardiac care for noncardiac surgery?

Yes, we can!

Perioperative Medication Management

• Beta Blockers continue

• Alpha agonists continue

• Calcium blockers continue prn

• ACE / ARB stop preoperatively start when stable

• Statins continue

• Diuretics as needed

• THANK YOU