CARDIAC ANESTHESIA

1. Perioperative Management of Cardiac
patients With Coronary Stents
Lecturer Of Anesthesiology And Intensive Care
, Al-Azhar University
pediatric cardiac anesthesiologist
Ali_m7areak@yahoo.com
ALI AHMED MAHAREAK, MD

2. Coronary Artery Disease
 Myocardial ischemia results from the reduction of
coronary blood flow to an extent that leads to
decrease in oxygen supply to myocardial tissue
 prolonged & irreversible ischemia myocardial cell
death & necrosis ---this is defined as
myocardial infarction
 Leading cause of death
 Caused by buildup of plaque

3. Risk factors
 Age
 Gender
 Genes
 High blood pressure (hypertension)
 High blood cholesterol
 Smoking
 Obesity
 Physical inactivity
 Diabetes
 Stress

4. Major Risk Factors:
The Big Three
• Hypertension
• High cholesterol
• Cigarette smoking
All three increase risk
factor eight times
AND…. we should add LACK OF EXERCISE

5. Major Risk Factors

6. Major Risk Factors

7. Biochemical Changes in Acute Myocardial Infarction
(mechanism of release of myocardial markers)
ischemia to myocardial muscles (with low O2 supply)
anaerobic glycolysis
increased accumulation of Lactate
decrease in pH
activate lysosomal enzymes
disintegration of myocardial proteins
cell death & necrosis
release of intracellular
contents to blood
BIOCHEMICAL
MARKERS
clinical manifestations
(chest pain)
ECG
changes

8. Pathophysiology of Coronary Artery Disease
Chest pain

9. Diagnosis for Coronary Artery Disease
Symptoms
Symptoms ECG TESTS
• Chest pain
• Fatigue
• Shortness of
breath
• Weakness
•S-T segment elevation
•S-T segment depression
•Hyper-acute T-waves
•T-wave inversion
•Pathological Q-waves
•Left bundle branch block
•Cardiac enzymes
•Echocardiography
•Exercise Stress Test
•Nuclear Stress Test
•CT Scan
•Coronary Angiograph
ECG TESTS

10. Horizontal ST depression

11. ST-Segment Elevation

12. Hyperacute T waves

13. Inferior T-wave inversion

14. Non-ST Elevation Infarction
ST depression & T-wave inversion
The ECG changes seen with a non-ST elevation infarction are:
Before injury Normal ECG
ST depression & T-wave inversion
ST returns to baseline, but T-wave
inversion persists
Ischemia
Infarction
Fibrosis

15. Non-ST Elevation Infarction
Note the ST
depression and
T-wave inversion
in leads V2-V6.

16. Cardiac enzymes

17. ECHOCARDIOGRAPHY

18. ECHOCARDIOGRAPHY

19. Treatment Options for Coronary
Artery Disease
Medications
Balloon
angioplasty
Coronary
stenting
CABG

20. What is a Stent
 A small, mesh-like device
made of metal
 Acts as a support in keeping
the vessel open
 Stent helps to improve blood
flow to the heart muscle and
reduce the pain of angina

21. Scope of the Problem
 In the US over 600,000 percutaneous
coronary interventions (PCI) are done every
year
 The majority of PCIs involve drug eluting stent
placement
 About 5% of patients undergoing PCI will need
non-cardiac surgery within 1 year
 Roughly 1% of elective non-cardiac surgery
pts. had PCI in the preceding year

22. What Problems are There?
Increased risk of myocardial infarction
Risk of stent thrombosis
Increased risk of bleeding due to DAPT

23. Bare metal stents:
 Traditional method
 May have an increased rate of re-narrowing due to
growth of scar tissue in the stent, a condition called
Restenosis.
Drug-eluting stents:
 Combat Restenosis
 Controlled release of medicine into tissue
 Drug limits overgrowth of natural tissue
Types of Stent

25. Limitations of Stents
Stent Thrombosis
• Formed the concept of DAPT
Durability – (Restenosis)
• Neointimal hyperplasia got worse
• Restenosis rates were 20-30%
• Small Vessels, Diabetics, diffuse disease all had
even higher restenosis rates

26. Coronary Restenosis
•30-40%
Balloon
angioplasty
•20-30%BMS
•4-5%DES

27. Why Cardiologists Love PCI & DES
PCI reduces mortality and morbidity in acute
coronary syndromes
PCI is effective in controlling anginal symptoms
Patient recovery time is short
Long term durability is very good

28. Limitations of Drug eluting stents
• Increased, but later, stent thrombosis in DES
• Late (>30 days)
• Very Late (>1 year)
• Inhibition of neo-intimal growth also inhibits
endothelial formation inside the stent
• Long term (12 month) Plavix is recommended

29. Bleeding Stent Thrombosis
Balance

30. Stent Thrombosis
 Stent thrombosis
– Acute –first 24 hours
– Sub-acute – first month
– Late – first year
– Very late - > 1 year
 Stent thrombosis is a serious adverse event, commonly
associated with MI and even sudden cardiac death
 STH is associated with up to 70% rate of MI and 20%
mortality
 Overall stent thrombosis rate is 1-2 % in first year

31. Stent Thrombosis
High risk
<1 month after PCI with BMS
<6 months after PCI with DES
<12 months after complex PCI with DES (long
stents, multiple
stents, overlapping, small vessels,
bifurcations, left main, last remaining vessel)

32. Dual Anti-Platelet Therapy (DAPT)
 Stent implantation is a thrombogenic
procedure.
DAPT is the cornerstone of oral antiplatelet therapy for
the prevention of stent thrombosis
Aspirin irreversibly inhibits platelet cyclooxygenase
(COX-1)
The thienopyridines [e.g., clopidogrel (Plavix®)]
irreversibly bind to the platelet P2Y12 receptor and
inhibit ADP - mediated platelet activation and
aggregation

33. Dual Anti-Platelet Therapy (DAPT)
Aspirin and a P2Y12 inhibitor
Duration:
 2 weeks following PCI
 6 weeks following bare metal stent
 12 months following DES
 12 months following MI
Continuation of aspirin indefinitely
Risk of thrombosis is increased more than 14 folds and 1-year
mortality is increased 10 folds if DAPT is stopped prematurely

34. Stent Thrombosis
Surgery
During surgery there is a hypercoagulable
state induced:
oIncreased inflammation and platelet
activation
oincreased catecholamine release
odecreased fibrinolysis

35. Bleeding Risk During Surgery
Aspirin alone 2.5% to 20%
DAPT 30% to 50%
Intracranial procedures
Spine
Major vascular
fatal bleeding
No increased risk of bleeding-related mortality except
during intracranial, spine and vascular surgeries

36. Bleeding
ASPIRIN 2.5% to 20%
DAPT 30% to 50%
Mortality in brain, spine and
vascular surgeries only
Balance
Stent Thrombosis
 Overall rate is 1-2 % in first year
 Premature stopping 14 folds
 70% rate of MI and 20%
mortality

37. Surgical Risk and Timing
• Non cardiac surgery done less than 6 weeks
after PCI has the highest mortality
• The single biggest predictor of stent
thrombosis is discontinuation of anti-platelet
therapy

38. Surgical Risk and Timing
Bare Metal Stent:
• Risk of death, MI and stent thrombosis is
increased 5% to 30% if surgery is performed
within 6 weeks of placement.
• Emergency surgery triples the risk of adverse
events compared with elective surgery.

39. Surgical Risk and Timing
Drug-Eluting Stent:
 Risk of major adverse cardiac events is very
significant if antiplatelet therapy is
discontinued and noncardiac surgery
performed within 1 year.
 Emergency surgery is associated with a 3.5-
fold increase in adverse events compared with
elective surgery

40. Strategies for Peri-op Management of DES
ELECTIVE SURGERY
 Elective surgery should be delayed at least until
12 months post DES
 Plavix- if stopped - 5 to 7 days pre-op, continue
aspirin if at all possible
 Resume Plavix with 300 or 600mg loading dose

41. Strategy for Peri-op Management of DES
ELECTIVE SURGERY
 Perioperative Monitoring: Urgent cardiac evaluation should be
performed if perioperative angina occurs.
Anesthetic Technique: Neuraxial blockade is avoided patients
undergoing DAPT.
 Platelets: can be administered for bleeding
 Availability of Interventional Cardiology: Patients should
be triaged to an interventional cardiologist within 90 minutes of
a diagnosis or suspicion of acute MI or acute stent thrombosis

42. Strategy for Peri-op Management of DES
 “Bridging Therapy” with GP IIb/IIIa inhibitor
 Stop Plavix 5-7 days pre-op
 Admit 2-3 days pre-op and start IIb/IIIa
 Continue aspirin throughout if possible
 Restart Plavix as soon as possible post-op

43. Strategies for Peri-op Management of DES
URGENT SURGERY
Urgent-Emergent surgeries have 4-fold
higher mortality

44. Strategy for Peri-op Management of DES
URGENT SURGERY
• Continue DAPT if possible - stent thrombosis risk is
high
• Closed/confined space – intracranial, spinal medullary,
posterior chamber ophthalmic surgeries will need
DAPT discontinued
• If P2Y12 inhibitor stopped, try to maintain aspirin
• Restart the P2Y12 inhibitor post surgery (within 24
hours if possible, with 300mg bolus).

45. Strategies for Peri-op Management of DES
Post Op issues
• Resumption of DAPT as soon as possible
• Using bolus dose of P2Y12 inhibitor
• Intensive post–op monitoring if off DAPT
• Prompt evaluation and intervention for stent
thrombosis or any bleeding

46. Strategies for Peri-op Management of DES
Post-op Stent Thrombosis
• Usually presents as ST elevation MI
• Fibrinolytic therapy is contraindicated
• Primary PCI is the treatment of choice

47. Pharmacologic Management
β-Blockers:
 Currently, the only class I recommendation is to
continue them in patients who are already
receiving them.
Other patients who may benefit from β-blockers
include:
 undergoing vascular surgery
 Patients have multiple cardiac risk factors
 Patients show reversible cardiac ischemia on preoperative testing

48. Pharmacologic Management
 α2-Agonists: have analgesic, sedative, and
sympatholytic effects and may be useful
 Nitrovasodilators
 Statin therapy: may be beneficial if started
1 to 4 weeks before high-risk surgery.
 Hyperglycemia: must be controlled (180
mg/dl).
 Anxiety must be treated

49. Intraoperative Management
Goals:
• to prevent myocardial ischemia by optimizing
myocardial oxygen supply and reducing myocardial
oxygen demand
• keep the heart rate and blood pressure within 20%
of the normal awake value
• to monitor for and treat ischemia
Maintenance of the balance between myocardial oxygen
supply and demand is more important than the specific
anesthetic technique or drugs selected to produce
anesthesia and muscle relaxation

50. DECREASED OXYGEN DELIVERY
 Decreased coronary blood flow
 Tachycardia
 Diastolic hypotension
 Hypocapnia
 Coronary artery spasm
 Decreased oxygen content
 Anemia
 Arterial hypoxemia
 Shift of the oxyhemoglobin dissociation curve to
the left

51. INCREASED OXYGEN REQUIREMENTS
 Sympathetic nervous system stimulation
 Tachycardia
 Hypertension
 Increased myocardial contractility
 Increased afterload
 Increased preload

52. Approach to the Management of Patients with
Previous PCI Who Require Noncardiac Surgery
Balloon
angioplasty
Bare-metal
stent
Drug-eluting
stent
Delay for elective or
nonurgent surgery
<14 days
Proceed to the
operation room
with aspirin
Delay for elective or
Nonurgent surgery
>30- 45 days <30- 45 days
Proceed to the
operating room
with aspirin
>365 days
Previous PCI
Time since
PCI
<365 days
>14 days

53. Treatment for Patients Requiring PCI
Who Need Subsequent Surgery
Balloon
angioplasty
Bare-metal
stent
Drug-eluting
stent
14-29 days 30-365 days >365 days
Bleeding risk of surgery
Timing of surgery
Acute MI, H risk ACS
Stent & continue
dual antiplatelet
therapy
low
Not low