ANESTHESIA FOR NON CARDIAC SURGERY IN PATIENTS WITH CORONARY STENTS

ANESTHESIA FOR NON CARDIAC SURGERY IN PATIENTS WITH CORONARY STENTS

Dr. Mahesh VakamudiProfessor and HeadDepartment of Anesthesiology, Critical Care and Pain Medicine (ISO 9001:2008 CERTIFIED)Sri Ramachandra UniversityChennai

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

Coronary artery bypass

surgeries

Percutaneous coronary

interventions

NUMBER

>Stents

commonly placed

Increase procedural

successDecrease restenosi

s

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

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

Scoring system for LST

Risk score for prediction of LST

Renal failure 6 pointsBifurcation lesion 6 pointsDiabetes 4 pointsBrachytherapy 2.5 pointsEach 20% fall in EF 0.25 points

Low0 6 9 1

319

Medium High Very High

Why thrombosis?

Stents not endothelializ

ed

Prothrombotic state due to surgery

Stopping antiplatelets

STENT THROMBOSIS

Early surgery

Discontinuation of Aspirin and Clopidogrel

Loss of antiplatelet effect

Rebound increase in COX 1 and

TXB2Increased

thrombin and decreased fibrinolysis

Surgery Prothrombotic state

Loss of anti-inflammatory protection

by clopidogrel

Stent thrombos

is

MI⁺ &

Coronary angioplasty

without stents

Abrupt vessel collapse due to acute recoil and

vasospasm

Bare metal stents

Stent placement injures vessel wall and causes scar

tissue growth inside the stent

Stent restenosi

s

Drug eluting stents

Platform + Carrier

(Stent + Drug)

Antiproliferative and immunosuppressive

properties

Prevent neointimal hyperplasia

Delay endothelializati

onbut

Late stent thrombosis

Incidence of deaths

Bare metal stents

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.

8 out of 25 patients who underwent surgery within 2 weeks died – 7 of

MI, 1 of bleedingNone out of 15 patients who underwent surgery after 15 days

died

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.

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

Sharma AK, Ajani AE, Hamwi SM, et al. Major noncardiac surgeryfollowing coronary stenting: when is it safe to operate? CatheterCardiovasc Interv 2004;63:141–5.

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

Bare metal stents

DES

First generation DES elute Sirolimus Paclitaxel

Second generation DES elute Zotarolimus Everolimus

Nasser et al. (20) reported sirolimus-eluting stent (SES) thrombosis in 2 patients after surgery

performed 4 and 21 months after SES implantation.

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

days) after implantation.

Drug eluting stents

Avoid preoperative coronary stenting

Stent selection (BMS vs DES)

Delay surgery

Optimize antiplatelet therapy

Education and collaboration

Avoid preoperative coronary

revascularization, unless there exists a strong and proven

indicationConsider balloon angioplasty if

surgery is needed within 6 weeks.

Avoid stents

Choose BMS ifSurgery needed from

6 weeks to 12 months

Bleeding diathesisPatient unable or unwilling to receive

long term clopidogrel

Choose DES if surgery is

needed after 12 months

BMS – 6 weeksDES – 12 monthsContinue

antiplatelet therapy during

surgerySurgeonsanesthesiologi

sts cardiologists

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 groupsSo, first ask the question:

Is revascularization necessary?

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

Perioperative cardiovascular morbidity in patients with coronary arterydisease undergoing vascular surgery after percutaneous transluminalcoronary angioplasty. J Cardiothorac Vasc Anesth 1998;12:501– 6.

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

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

Delay surgery

6 weeks BMS 12 months DES

Time from stent until surgery (months)

Major adverse cardiac events (%)

10

8

6

4

2

02 4 6 8 1

012

14

16

18

0

Bare metal stents

Drug eluting stents

RISK OF PERIOPERATIVE STENT THROMBOSIS WITH DES

Stents implanted in left main coronary arteryStents implanted in bifurcations

Greater total stent length (multiple/overlapping stents)

Heightened platelet activity (surgery, DM, malignancy)

In stent restenosisLeft ventricular dysfunction

Localized hypersensitivity vasculitisPenetration by stent into necrotic core

Plaque disruption into non stented segmentRenal failure

Diabetes mellitusResistance to antiplatelets

Inappropriate discontinuation of antiplatelet medications

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

cardiac surgery?

Periop antiplatelet 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

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

Option 1 : Continue therapy Dental extractions Cataract surgery Dermatologic surgery

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

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

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.

When bridging therapy?

Surgeries with high risk of bleeding Intracranial Spinal Retinal

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.

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

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)

Anesthetic drugs metabolized by CYP3A4

like midazolam can irreversibly inhibit this

enzyme which metabolizes clopidogrel

into its active form, modulating its

antiplatelet effect

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

Steps

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

Intraop management

Tight hemodynamic control Use of beta blockers Good HR control Good BP control Decrease sympathetic outflow and

therefore decrease platelet activation

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

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

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 plateletsPlatelet transfusions to be avoided

except in instances of life threatening bleeding

Algorithm for patients with DES for NCSEmergen

cySemi

emergencyElectiv

eAssess risk of

bleedingLow Intermediat

eHigh

Length of DAPT< 1 yr

> 1 yr

Stop clopidogrelContinue LD

aspirinProceed

with surgery

DES > 1 yr

DES < 1 yr

Continue DAPT

Stop Anti PLT

Assess risk of thrombosis

Low HighHosp Admn ? IV Anti PLT

STOP

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 fornoncardiac surgery following coronary stent insertion: views of Canadiananesthesiologists. Can J Anaesth 2005;52:440 –1

Take home points

Many patients come for non cardiac surgery after PCI

Stent thrombosis is a catastrophe Remember the stepwise approach to

the issue

Avoid preoperative coronary stenting

Stent selection (BMS vs DES)

Delay surgery

Optimize antiplatelet therapy

Education and collaboration

Thank you