Rhett StentsPlatelets

7/27/2019 Rhett StentsPlatelets

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Perioperative management of

antiplatelet therapy in patientswith coronary artery stents

Esi Rhett, MD

Davide Cattano, MD PhD

The Department of Anesthesiology Grand Round Series

March 19, 2009
http://www.uthouston.edu/index/index.htm


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Disclaimer

No financial interest

Patient verbal consent has been obtained

All patients information has been de-identified

and the use of it is restricted to quality

improvement of medical practice


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Learning Objectives

Understand the value of preoperative cardiac evaluation and risk

stratification and the clinical indication for antiplatelet therapy.

Basic knowledge of platelet function and coagulation.

How aspirin and clopidogrel work

Understand the current ACC/AHA and ASA guidelines on the use of

thromboprophylaxis and coronary stents and the limitations.

How to (ideally) approach the patient on antiplatelet therapy

Introduction to the concept of resistance to antiplatelet medications

Future projects


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Introduction

Heart disease continues to be the #1 cause ofmorbidity and mortality in the United States andwestern nations.

Acute coronary syndrome- conditions related tomyocardial ischemia ranging from stable angina toQ-wave myocardial infarction. (1.6 million Americans: 700,000unstable angina and 900,000 divided btwn STEMI and NSTEMI)

Percutaneous coronary intervention (balloonangioplasty and stent placement) offers patientsimproved quality of life by decreasing angina andrisk for myocardial infarction and death.


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Introduction

A major concern after successful coronary artery

stent placement is the potential for acute stent

thrombosis, with subsequent myocardial infarctionand death.

American Society of Anesthesiologists. Practice Alert for the Perioperative Management ofPatients with Coronary Stents. Anesthesiology 2009; 110(1): 22-23.


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Introduction

To prevent stent thrombosis,cardiologists recommenddual antiplatelet medications

consisting of a combinationof aspirin and athienopyridine usuallyclopidogrel.

However, when these patients

present for surgery, there is afear that platelet dysfunctioncan cause surgical site

bleeding.


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Why are these patients on

antiplatelet therapy anyway? Percutaneous Coronary Intervention is inherently

thrombogenic because it disturbs the artery walls.

Drug eluting stents slowly release medications toprevent reendotheliaztion of the artery wall, this

leaves tissue factor exposed where the coagulation

cascade and platelet aggregation can occur.

Surgery is thrombogenic because it causes tissue

damage and inflammation.


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The patient:

Mr. Smyth, 36 year old Caucasian man

Presented to the Anesthesia Clinic December 2008, repeat

anterior cervical 6 and 7 decompression with fusion

MedHx: HTN, dyslipidemia, DM II for 3 years, cervical

herniated disc, ACS in 2003, 2008

In March 2003, when he was only 31 years old, he had an

episode of unstable angina, angiogram revealed a >95%

occlusion in the LAD and received a sirolimus drug eluting

stent.


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The patient cont:

PSx: March 2008, first anterior cervical 6-7 discdecompression with fusion, uneventful hospitalcourse.

He reported had another MI 3/25/08 in Dallas.

Meds: clopidogrel, aspirin (last dose one weekbefore clinic visit), ramipril, metoprolol,

glucophage, atorvostatin, and hydrocodone-acetaminophen

Social: non smoker, occ ETOH


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What other information do you need to

determine the patients risk for surgery? He is unable to give any family history of cardiac disease

or premature cardiac death because he is adopted.

He tolerates some physical activity; he is able to do work

around the house and climb stairs without any chest pain or

shortness of breath.

Cath(5/08) LAD stent patent with multiple other vessel

with disease but recommend medical management for now

ECHO: EF 60-65%

EKG: normal sinus rhythm, no evidence of ST changes or

Q waves


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What other information do you need to

determine the patients risk for surgery?

Vital signs: T96.5, B/P 123/79, P78, 97% on RA

Laboratory data significant for elevated glucose of

196mg/dL, Hb 13.7, all other labs wnl.


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Would you want to stop his

clopidogrel and aspirin for this

procedure again? Plan A: stop both clopidogrel and ASA

Plan B: continue both clopidogrel and ASA

Plan C: Admit the patient for short term

antiplatelet therapy

Plan D: cancel the surgery


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American Society of Anesthesiologists. Practice Alert for the

Perioperative Management of Patients with Coronary

Stents. Anesthesiology 2009; 110(1): 22-23.2007 Science Advisory

Drug Eluting stents (DES)- delay non cardiacsurgery with high risk bleeding for 12

months, thienopyridine and ASA for 12months

Bare Metal Stents (BMS)- delay electivenon-cardiac surgery a minimum of 1 month(4-6 weeks depending on type of BMS), ASA4-6 weeks

(Angioplasty alone delay for 3 weeks)


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Fleisher LA, et al. ACC/AHA 2007 Guidelines on

Perioperative Cardiovascular Evaluation and Care for

Noncardiac Surgery: Executive Summary. J Am Coll Cardiol2007; 50(17): 1707-1732.

In patients who have received drug-eluting

coronary stents and who must undergo

urgent surgical procedures that mandate thediscontinuation of the thienopyridine

therapy, it is reasonable to continue aspirin

if at all possible and restart thethienopyridine as soon as possible.


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Coagulation/Platelet


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Hemostasis

Vascular spasm

Platelet plug (primary

hemostasis) Blood coagulation

(secondary

hemostasis)

Platelet Plug

3 Stages

1.Adhesion2. Release of platelet

granules

3.Aggregation

Morgan and Mihkail, Hepatic Physiology and Anesthesia p783-785


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Clopidogrel: mechanism of action


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Aspirin: mechanism of action


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Aspirin: mechanism of action


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Resistance to antiplatelet therapy

Resistance and differences in response to

antiplatelet medication has been known and

investigated in recent years. Clopidogrel is a prodrug that must be

converted to the active form by

cytochrome-p450 enzymes


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0

20

40

60

80

100

Aggregation(%)

80 9

37 20

5.0

4.0

3.0

2.0

1.0

0

1.9 0.7

2.7 1.0

Platelet aggregation

4 hours post clopidogrel*

*450 mg PO (P=0.0002); **P=0.15

Nonresponders (25%)

14C

O2exhaled/h(%)

Clopidogrel Nonresponsiveness

Correlation with CYP3A4 Enzyme Activity

Lau WC et al. J Am Coll Cardiol. 2003;41:225A.

Responders (75%)

CYP3A4** activity


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Major questions

How do we test antiplatelet therapy

response?

When (If) to stop antiplatelet therapy?

When to restart?

How much to restart: maintenance dose v

loading dose?

What happens after 2 and 12months?


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Platelet Function Monitoring

Clinical tests: Bleeding time , Platelet Funcion

Assay-100, platelet aggregometry and the TEG

Thromboelastogram: advantage of being able tomonitor ASA and thienopyridines and other

GPIIb/IIIa inhibitors

Gurbel PA, Becker RC, et al. Platelet Function Monitoring in Patients with Coronary Artery Disease. J Am

Coll Cardiol 2007; 50(19): 1822-1834. Review.


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What happened to Mr. Smyth?

Surgeons will not like idea of continuing

antiplatelet medications.

When the surgeon was asked to considermaintaining at least the ASA, he refused.

He did accepted restarting ASA the same

day post op and the clopidogrel 48 hrs later.


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What happened to Mr. Smyth?

Surgery proceeded without incident and he was

discharged after a uneventful hospital course.

He was given aspirin 81mg chewable in house. It is unknown when (or if) he restarted the

clopidogrel.

Follow-up phone call showed a disconnected

number


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Conclusions

Drug Eluting stents:

Delay surgery for 12

months if possible tocomplete therapy

Continue ASA and

restart clopidogrel

ASAP

Bare Metal Stents:

Delay for 2 months

Continue ASA andrestart clopidogrel

ASAP

Memorial Hermann Hospital: UT system proposal


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Perioperative management of antiplatelet agents in

noncardiac surgery.

Eur J Anaesthesiol. 2009 Mar;26(3):181-7. Links

Llau JV, Lopez-Forte C, Sapena L, Ferrandis R.

Department of Anaesthesiology and Critical Care

Medicine, University Clinic Hospital, Valencia, Spain.
https://webmail.uth.tmc.edu/owa/UrlBlockedError.aspxhttps://webmail.uth.tmc.edu/owa/redir.aspx?C=6825d4368d4a4ecb968e59362d843899&URL=http%3a%2f%2fwww.ncbi.nlm.nih.gov%2fsites%2fentrez%3fDb%3dpubmed%26Cmd%3dSearch%26Term%3d%2522Llau%2520JV%2522%255BAuthor%255D%26itool%3dEntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DiscoveryPanel.Pubmed_RVAbstractPlushttps://webmail.uth.tmc.edu/owa/redir.aspx?C=6825d4368d4a4ecb968e59362d843899&URL=http%3a%2f%2fwww.ncbi.nlm.nih.gov%2fsites%2fentrez%3fDb%3dpubmed%26Cmd%3dSearch%26Term%3d%2522Lopez-Forte%2520C%2522%255BAuthor%255D%26itool%3dEntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DiscoveryPanel.Pubmed_RVAbstractPlushttps://webmail.uth.tmc.edu/owa/redir.aspx?C=6825d4368d4a4ecb968e59362d843899&URL=http%3a%2f%2fwww.ncbi.nlm.nih.gov%2fsites%2fentrez%3fDb%3dpubmed%26Cmd%3dSearch%26Term%3d%2522Sapena%2520L%2522%255BAuthor%255D%26itool%3dEntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DiscoveryPanel.Pubmed_RVAbstractPlushttps://webmail.uth.tmc.edu/owa/redir.aspx?C=6825d4368d4a4ecb968e59362d843899&URL=http%3a%2f%2fwww.ncbi.nlm.nih.gov%2fsites%2fentrez%3fDb%3dpubmed%26Cmd%3dSearch%26Term%3d%2522Ferrandis%2520R%2522%255BAuthor%255D%26itool%3dEntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DiscoveryPanel.Pubmed_RVAbstractPlushttps://webmail.uth.tmc.edu/owa/redir.aspx?C=6825d4368d4a4ecb968e59362d843899&URL=http%3a%2f%2fwww.ncbi.nlm.nih.gov%2fsites%2fentrez%3fDb%3dpubmed%26Cmd%3dSearch%26Term%3d%2522Ferrandis%2520R%2522%255BAuthor%255D%26itool%3dEntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DiscoveryPanel.Pubmed_RVAbstractPlushttps://webmail.uth.tmc.edu/owa/redir.aspx?C=6825d4368d4a4ecb968e59362d843899&URL=http%3a%2f%2fwww.ncbi.nlm.nih.gov%2fsites%2fentrez%3fDb%3dpubmed%26Cmd%3dSearch%26Term%3d%2522Sapena%2520L%2522%255BAuthor%255D%26itool%3dEntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DiscoveryPanel.Pubmed_RVAbstractPlushttps://webmail.uth.tmc.edu/owa/redir.aspx?C=6825d4368d4a4ecb968e59362d843899&URL=http%3a%2f%2fwww.ncbi.nlm.nih.gov%2fsites%2fentrez%3fDb%3dpubmed%26Cmd%3dSearch%26Term%3d%2522Lopez-Forte%2520C%2522%255BAuthor%255D%26itool%3dEntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DiscoveryPanel.Pubmed_RVAbstractPlushttps://webmail.uth.tmc.edu/owa/redir.aspx?C=6825d4368d4a4ecb968e59362d843899&URL=http%3a%2f%2fwww.ncbi.nlm.nih.gov%2fsites%2fentrez%3fDb%3dpubmed%26Cmd%3dSearch%26Term%3d%2522Lopez-Forte%2520C%2522%255BAuthor%255D%26itool%3dEntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DiscoveryPanel.Pubmed_RVAbstractPlushttps://webmail.uth.tmc.edu/owa/redir.aspx?C=6825d4368d4a4ecb968e59362d843899&URL=http%3a%2f%2fwww.ncbi.nlm.nih.gov%2fsites%2fentrez%3fDb%3dpubmed%26Cmd%3dSearch%26Term%3d%2522Lopez-Forte%2520C%2522%255BAuthor%255D%26itool%3dEntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DiscoveryPanel.Pubmed_RVAbstractPlushttps://webmail.uth.tmc.edu/owa/redir.aspx?C=6825d4368d4a4ecb968e59362d843899&URL=http%3a%2f%2fwww.ncbi.nlm.nih.gov%2fsites%2fentrez%3fDb%3dpubmed%26Cmd%3dSearch%26Term%3d%2522Llau%2520JV%2522%255BAuthor%255D%26itool%3dEntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DiscoveryPanel.Pubmed_RVAbstractPlushttps://webmail.uth.tmc.edu/owa/UrlBlockedError.aspx


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Up and coming research

Dr. Ali Denktas and Dr. Evan Pivalizza

Safety Implications of Patients receiving Preoperative Antiplatelet therapy

with Clopidgrel and/or Aspirin:Investigation of Thrombelastograph PlateletMapping to objectively assess Platelet Inhibition and subsequent use to guide

individual patient management. PI Evan Pivalizza, CO-PI Davide Cattano.

Perioperative management of antiplatelet therapy (Clopidogrel);

retrospective chart review. PI Ali Denktas, CO-PIDavide Cattano.


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Thank you!

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