ANESTHESIA FOR NON CARDIAC SURGERY IN PATIENTS WITH CORONARY STENTS
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ANESTHESIA FOR NON CARDIAC SURGERY IN PATIENTS WITH CORONARY STENTS







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Dr. Mahesh Vakamudi Professor and Head Department of Anesthesiology, Critical Care and Pain Medicine (ISO 9001:2008 CERTIFIED) Sri Ramachandra University Chennai. ANESTHESIA FOR NON CARDIAC SURGERY IN PATIENTS WITH CORONARY STENTS. Magnitude of the problem.
ANESTHESIA FOR NON CARDIAC SURGERY IN PATIENTS WITH CORONARY STENTS

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Slide 1

Dr. Mahesh Vakamudi

Professor and Head

Department of Anesthesiology, Critical Care and Pain Medicine

(ISO 9001:2008 CERTIFIED)

Sri Ramachandra University

Chennai

ANESTHESIA FOR NON CARDIAC SURGERY IN PATIENTS WITH CORONARY STENTS

Slide 2

Magnitude of the problem

  • 2 million patients undergo PCI annually

  • 90% of these patients receive one or more intracoronary stents

  • 5% of these patients will undergo non cardiac surgery in the first year after stenting

Slide 3

NUMBER

Percutaneous coronary interventions

>

Coronary artery bypass surgeries

Increase procedural success

Stents commonly placed

Decrease restenosis

Slide 4

Why this lecture?

  • In patients who have coronary stents, perioperative coronary stent thrombosis is a catastrophic complication

  • Non cardiac surgery, especially if surgery is performed immediately after stenting and particularly if dual antiplatelet therapy is discontinued – increases this risk

  • Maintain balance between risk of bleeding and stent thrombosis is our dilemma.

  • What do we do? That’s what this lecture is about

Slide 5

Which patients are prone for stent thrombosis?

  • Patients with a suboptimal angiographic result

  • Those with high risk lesions

    • Small vessels

    • Bifurcation lesions

  • Those with diabetes and renal failure

  • Those whose dual antiplatelet therapy has been stopped

Slide 6

Scoring system for LST

Risk score for prediction of LST

Low

Medium

High

Very High

0

6

9

13

19

Slide 7

Why thrombosis?

Early surgery

STENT THROMBOSIS

Slide 8

Discontinuation of Aspirin and Clopidogrel

Loss of anti-inflammatory protection by clopidogrel

Rebound increase in COX 1 and TXB2

Loss of antiplatelet effect

Increased thrombin and decreased fibrinolysis

Stent thrombosis

&

Surgery

Prothrombotic state

MI

Slide 9

Coronary angioplasty without stents

Abrupt vessel collapse due to acute recoil and vasospasm

Stent placement injures vessel wall and causes scar tissue growth inside the stent

Stent restenosis

Bare metal stents

Prevent neointimal hyperplasia

Delay endothelialization

Drug eluting stents

but

Antiproliferative and immunosuppressive properties

Late stent thrombosis

Platform + Carrier

(Stent + Drug)

Slide 10

Incidence of deaths

Bare metal stents

8 out of 25 patients who underwent surgery within 2 weeks died – 7 of MI, 1 of bleeding

None out of 15 patients who underwent surgery after 15 days died

Kaluza GL, Joseph J, Lee JR, Raizner ME, Raizner AE.

Catastrophic outcomes of noncardiac surgery soon after coronary stenting.

J Am Coll Cardiol 2000;35:1288 –94.

Slide 11

Bare metal stents

The risk of death, MI, or stent thrombosis was elevated for 6 weeks, not for just 2 weeks

Of 27 patients who underwent non cardiac surgery within 3 weeks of BMS, 86% of those who stopped antiplatelets died

Sharma AK, Ajani AE, Hamwi SM, et al. Major noncardiac surgery

following coronary stenting: when is it safe to operate? Catheter

Cardiovasc Interv 2004;63:141–5.

Wilson SH, Fasseas P, Orford JL, et al. Clinical outcome of patients undergoing noncardiac surgery in the two months following coronary stenting. J Am Coll Cardiol 2003;42:234–40.

Slide 12

DES

  • First generation DES elute

    • Sirolimus

    • Paclitaxel

  • Second generation DES elute

    • Zotarolimus

    • Everolimus

Slide 13

Drug eluting stents

McFadden et al. (19) reported DES thrombosis in 3 patients undergoing surgery late (343 to 442 days) after implantation.

Nasser et al. (20) reported sirolimus-eluting stent (SES) thrombosis in 2 patients after surgery performed 4 and 21 months after SES implantation.

Slide 14

Avoid preoperative coronary stenting

Avoid preoperative coronary revascularization, unless there exists a strong and proven indication

Choose BMS if

Surgery needed from 6 weeks to 12 months

Bleeding diathesis

Patient unable or unwilling to receive long term clopidogrel

Stent selection (BMS vs DES)

Consider balloon angioplasty if surgery is needed within 6 weeks. Avoid stents

Delay surgery

Choose DES if surgery is needed after 12 months

BMS – 6 weeks

DES – 12 months

Optimize antiplatelet therapy

Continue antiplatelet therapy during surgery

Education and collaboration

Surgeons

anesthesiologists cardiologists

Slide 15

Avoiding revascularization

  • CARP trial

  • 510 stable patients with CAD undergoing major vascular surgery

  • Randomized to revascularization (by CABG or PCI) or no revascularization

  • Similar incidence of postoperative MI and 27 month survival in both the groups

So, first ask the question: Is revascularization necessary?

Slide 16

Revascularization without stents (Balloon only)

  • Patients with acute coronary syndrome and those with profound ischemia on non invasive testing do need revascularization

  • Can be done without stents: Percutaneous balloon angioplasty

  • In this study, when surgery was done 11 days after PCI, only 1 patient died and 1 had an AMI

Gottlieb A, Banoub M, Sprung J, Levy PJ, Beven M, Mascha EJ.

Perioperative cardiovascular morbidity in patients with coronary artery

disease undergoing vascular surgery after percutaneous transluminal

coronary angioplasty. J Cardiothorac Vasc Anesth 1998;12:501– 6.

Slide 17

When surgery after Balloon angioplasty?

  • 2002 ACC AHA guidelines

  • Delaying noncardiac surgery for 6 to 8 weeks was discouraged because restenosis could have occurred

  • Performing noncardiac surgery too early after the PCI also may be risky because acute or subacute closure after balloon angioplasty usually occurs within hours to days after the procedure.

  • Delay surgery for 1 week after balloon angioplasty

Slide 18

If stenting can’t be avoided

  • Complex lesion or inability to achieve optimal result with balloon angioplasty

  • Choose the right stent

  • Surgery needed with 12 months: Choose BMS

  • Surgery can be delayed for > 12 mth: DES

  • BMS endothelialize more rapidly than DES

  • Sirolimus eluting stent preferable as it requires 3 mths of antiplatelet therapy than a paclitaxel eluting stent that requires 6 mths of clopidogrel

Slide 19

Delay surgery

  • 6 weeks BMS

  • 12 months DES

Slide 20

Major adverse cardiac events (%)

Bare metal stents

10

Drug eluting stents

8

6

4

2

0

0

2

4

6

8

10

12

14

16

18

Time from stent until surgery (months)

Slide 22

What are the steps to prevent stent thrombosis in these patients coming for non cardiac surgery?

Slide 23

Periopantiplatelet therapy

  • Continue dual antiplatelet thearpy during and after surgery

  • Discontinue clopidogrel but “bridge” the patient to surgery with Glycoprotein IIb/IIIa inhibitor or an antithrombin, and restart clopidogrel as soon as possible after surgery

  • Discontinue clopidogrel before surgery and restart it as soon as possible after surgery

Slide 24

Impact of aspirin on bleeding

  • Most studies in cardiac and vascular surgery

  • Safe in doses of 75 – 150 mg

  • Increases bleeding by a factor of 1.5, no effect on morbidity and mortality

  • Avoid in TURP and intracranial surgery (as bleeding in these situations can be life threatening)

Continue aspirin monotherapy in elective non cardiac surgery

Slide 25

Option 1 : Continue therapy

  • Dental extractions

  • Cataract surgery

  • Dermatologic surgery

Slide 26

Option 2: Bridging therapy

  • Bridge using short acting antiplatelet or an anticoagulant

  • Platelet inhibitors are the more logical choice as stent thrombosis is a platelet mediated phenomenon

  • Cessation of heparin in a patient not on antiplatelets can cause rebound effect and stent thrombosis

Slide 27

Bridging therapy

  • A shortacting GP IIb/IIIa inhibitor (tirofiban or eptifibatide) or thrombin inhibitor, or both, is substituted for clopidogrel during the perioperative period

  • Role

    • Prevent platelet aggregation

    • Displace fibrinogen from GP IIb/IIIa receptors

    • Block signaling processes

Slide 28

Bridging therapy

  • Tirofiban and eptifibatide are administered parenterally

  • Have half-lives 2 h

  • Eliminated by renal clearance.

  • Infusion rate is reduced by half in patients with reduced renal function

  • Platelet function returns to 60%–90% of normal after the infusion is stopped for 6–8 h.

Slide 29

When bridging therapy?

  • Surgeries with high risk of bleeding

    • Intracranial

    • Spinal

    • Retinal

Slide 30

Other drugs

  • Reversible P2Y12 receptor antagonists are undergoing clinical trials

  • Cangrelor is a parenteral, reversible direct P2Y12 inhibitor

  • Half-life of 5–9 min allows 100% recovery of platelet function 1 h after the infusion is discontinued

  • 4 mcg/kg/min infusion achieves complete platelet inhibition when measured at 4 min

  • AZD6140 is an oral, reversible direct P2Y12 receptor antagonist with a half life of 12 hrs.

Slide 31

Problems with bridging therapy

  • Expensive

  • Logistically difficult

  • Exposes patients to risks associated with a prolonged hospitalization

  • Some claim that it confers no protection against intraoperative stent thrombosis

Slide 32

Option 3: Stop antiplatelets

  • Neurosurgery

  • Restart clopidogrel after surgery

  • 600 mg loading dose – Maximal inhibition of platelet aggregation in 2 – 4 hours (takes 6 hrs with 300 mg)

  • Reduces the incidence of hyporesponsiveness to platelets (which are activated due to surgery)

Slide 33

Anesthetic drugs metabolized by CYP3A4 like midazolam can irreversibly inhibit this enzyme which metabolizes clopidogrel into its active form, modulating its antiplatelet effect

Slide 34

Steps: Preoperative evaluation

  • Determine the type of stent: BES, SES, PES

  • When were stents implanted?

  • Determine location of stent in coronary circulation

  • How complicated was the revascularization?

  • Is there a previous history of stent thrombosis?

  • What antiplatelet regimen is being followed?

  • Determine co-morbidities?

  • What is the recommended duration of antiplatelet therapy for this patient?

  • Co-ordinate with cardiologist

Slide 35

Steps

  • Perform procedure in centers where there is 24 hr interventional cardiology coverage for emergency PCI

Slide 36

Intraop management

  • Tight hemodynamic control

  • Use of beta blockers

  • Good HR control

  • Good BP control

  • Decrease sympathetic outflow and therefore decrease platelet activation

Slide 37

Regional anesthesia in patients on antiplatelets

  • Advantages

    • Attenuation of hypercoagulable state

    • Systemically absorbed LA have antiplatelet effect

  • Follow ASRA guidelines

  • For patients receiving bridging therapy with eptifibatide or tirofiban, 8 h must elapse before a neuraxial blockade can be performed

Slide 38

Management of stent thrombosis

  • ST segment elevation acute myocardial infarction

  • Reperfusion

  • Thrombolytic therapy less effective than primary PCI

    • Platelet mediated phenomenon

    • Risk of bleeding

  • All that is required during PCI is aspirin and one dose of heparin or bivalirudin

Slide 39

Role of platelet transfusion

  • Transfused platelets are not inhibited by serum therapeutic levels of antiplatelets

  • The thrombogenic surface of stents may attract and activate donor platelets to an even greater extent than endogenous platelets

Platelet transfusions to be avoided except in instances of life threatening bleeding

Slide 40

Algorithm for patients with DES for NCS

Emergency

Semi emergency

Elective

Assess risk of bleeding

DES > 1 yr

DES < 1 yr

Low

Intermediate

High

STOP

Length of DAPT

Stop Anti PLT

Continue DAPT

> 1 yr

< 1 yr

Assess risk of thrombosis

Stop clopidogrel

Continue LD aspirin

Low

High

Proceed with surgery

Hosp Admn

? IV Anti PLT

Slide 41

Education

  • In a survey of anesthesiologists, 63% were not aware of recommendations about the appropriate length of time between stent placement and a subsequent surgical procedure, and one-third recommended no delay or a delay of only 1 to 2 weeks, which is insufficient for BMS, and even more so for DES

Patterson L, Hunter D, Mann A. Appropriate waiting time for

noncardiac surgery following coronary stent insertion: views of Canadian

anesthesiologists. Can J Anaesth 2005;52:440 –1

Slide 42

Take home points

  • Many patients come for non cardiac surgery after PCI

  • Stent thrombosis is a catastrophe

  • Remember the stepwise approach to the issue

Slide 43

Avoid preoperative coronary stenting

Stent selection (BMS vs DES)

Thank you

Delay surgery

Optimize antiplatelet therapy

Education and collaboration


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