Perioperative Myocardial Infarction - Etiology and Prevention

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Perioperative Myocardial Infarction- Etiology
and Prevention

• R3 ???

2
PMI

• Predictor of short- and long-term morbidity and
  mortality
• ??? ?? etiology? ? ??? ?
• Etiology ???? ???? ??
• ????? ???
• ?? ???? ??

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Etiology of PMI
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Acute Coronary Syndrome
Etiology of PMI

• Etiology
• ????
• plaque(structurallyfunctionally),
• coronary a. stenosis,
• coronary endothelial lesions,
• plaque inflammation
• Plaque
• structural morphology, cellular composition,
• biological activity
• exogenous factors (mechanical stress, vasomotor
  tone, infection, blood viscosity, coagulability)
• systemic or multi-focal arterial inflammation

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Acute Coronary Syndrome
Etiology of PMI

• Pathophysiology
• Plaque progression
• abrupt, unpreditable
• ?? thrombosis??? ??
• Risk factors triggers
• physical activity, mental stress,
  environmental
• temperature, smoking, infection, hydration,
  
• arterial pr.

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Acute Coronary Syndrome
Etiology of PMI

• Plaque rupture
• causes
• - mechanical stress, coronary vasospasm,
• widespread acute inflammatory endothelial
• activation, or the chronic inflammatory
• component of atherosclerosis
• size of thrombus
• strenuous physical activity emotional stress
• ? sympathetic tone?? ?????
• ? torombosis?
• ??? ??? ??!!

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Acute Coronary Syndrome
Etiology of PMI

• angiographically fairly small coronary lesion
• ? progress acutely to severe stenosis or total
  
• occlusion
• MI
• If coronary blood flow is interrupted for longer
  than 30 min, a MI may result
• ?????? size ??

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Perioperative MI
Etiology of PMI

• Etiology
• ?? ???? ????? ????? ??
• (CAG, EKG, oxygen supply/demand mismatch,
  plaque rupture)
• Most(gt80) PMIs occur early after surgery
• Asymptomatic, non-Q-wave type
• ST-seg depression(duration? ??)
• Serum troponin concentration
• HR? ??? ?????
• Prolonged stress-induced myocardial ischemia ?
  primary cause of PMI!!

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Perioperative MI
Etiology of PMI

• ??????, ??? ? ??
• (HR?, a.pr. ?, sympathetic tone?, procoagulant
  activity?)
• ??? CAD??? plaque? ??? ??? coronary a.
  thrombosis????
• Plaque disruption
• Thrombosis? thrombolysis?? ??, ??? flow condition

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Perioperative MI
Etiology of PMI

• Diagnosis
• MI Dx criteria (WHO)
• i) typical ischemic chest pain
• ii) increased serum concentration of creatine
  kinase (CK)-MB isoenzyme
• iii) typical electrocardiographic findings,
  including development of pathological Q-waves

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Perioperative MI
Etiology of PMI

• Revised definition of MI(by the ESC ACC)
• (1) typical rise and gradual fall in cardiac
• troponin concentrations or more rapid rise
• and fall of CK-MB concentration in
• combination with at least one of the
  following
• (a) typical ischemic symptoms
• (b) development of pathological Q-waves in the
  ECG
• (c) ECG changes indicative of myocardial ischemia
• (d) coronary a. intervention
• (2) pathological findings of an acute MI

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Perioperative MI
Etiology of PMI

• High specificity of cardiac troponin
• MI Troponin concentration
• cTnI gt 1.5 ng ml cTnT gt 0.1 ng ml
• Cardiac troponin? CK-MB?? ? ??
• ??? ?? ? underestimate
• troponin? ??? ?? ? overestimate
• Long term survival rate? ??
• ??? ??? ??? ??? ?????

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Prevention of Perioperative MI
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Preoperative Coronary Revascularization
Prevention of perioperative MI

• ???? improve perioperative and long-
• term outcome
• ???? ????? risk, ???? ?? ?
• ?? ?? ??

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Preoperative Coronary Revascularization
Prevention of perioperative MI

• Preoperative coronary angiography
• Positive DTS pts.?? ??
• Perioperative cardiac outcome??
• Cardiac evaluation?? MI 2?, death 3?
• ????? ??? ?? ???
• ?? ??? ????? ??? ??? ??? ???? ??

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Preoperative Coronary Revascularization
Prevention of perioperative MI

• Percutaneous transluminal coronary angioplasty
  (PTCA)
• ??? ??? design? ???? ??
• ??? ????? ??? ??? ??
• Angina pectoris congestive heart failure?
• but not in non-fatal PMI mortality
• ?? 90? ??? ??? ?? ??

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Preoperative Coronary Revascularization
Prevention of perioperative MI

• Coronary stenting
• Fatal cardiac event? ?? stent thrombosis
• ??? 6? ??? ??? ???? ??
• 79? ?? ??? ????? ???

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Preoperative Coronary Revascularization
Prevention of perioperative MI

• Preoperative surgical coronary revascularization
• ???? CABG??? ??? PMI? mortality?? ??? ?? ??
• Advanced angina multi-vessel CAD?? ?? ??
• Minor op.??? ??? ???
• CABG?? ? 1???? ??? ???? MI?, mortality?
• 6?? ?? ?? ??

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Preoperative Coronary Revascularization
Prevention of perioperative MI

• Risk calculation in preoperative coronary
  revascularization
• ?? ??? risk? ???? ???
• ?? ???? ??? ? risk? ??? ? ??
• ??? ?? ?? ?? ???? risk? ??
• Long-term outcome?? ???? ?
• (??? ??? ?? ???? ????)

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Preoperative Coronary Revascularization
Prevention of perioperative MI

• Recommendations for preoperative coronary
  angiography
• ????? ?? ??? ??? Ix? ??
• Ix
• (i) evidence for high risk of adverse outcome
  based on non-invasive test results
• (ii) angina pectoris unresponsive to adequate
  medical therapy
• (iii) unstable angina, particularly when facing
  intermediate or high risk non-cardiac surgery
• (iv) equivocal non-invasive test results in
  patients at high clinical risk undergoing high
  risk surgery

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Preoperative Coronary Revascularization
Prevention of perioperative MI

• Recommendation for preoperative coronary
  intervention
• ??? ???? ??? ???? ??
• PTCA
• Balloon plasty? ??? ? ???? ???? ?? ?? (??? ??? ?)

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Preoperative Coronary Revascularization
Prevention of perioperative MI

• Coronary stenting
• Dual antiplatelet medication
• (thienopyridine aspirin)
• Re-endothelialization (?? 8?)
• Re-stenosis (?? 6-8?)
• ???? ????? 2?
• 4-6?? ??
• Drug-eluting stent
• stent stenosis????, antipletelet ?????
• ?? ? ? ????? ??
• 2??? ??? ??? ??
• Dual antipletelet therapy? surgeon? ????
• drug-eluting stent? ??

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Preoperative Coronary Revascularization
Prevention of perioperative MI

• 2??? ??? ??? ??
• Dual antipletelet therapy? surgeon? ????
• drug-eluting stent? ??
• ?? ??? heparin-or phosphorylcholine-coated
  stent??? ???
• PTCA without stent placement

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Preoperative Coronary Revascularization
Prevention of perioperative MI

• Recommendation for preoperative surgical coronary
  revascularization
• ?? ????? ??? ??? Ix??
• Ix
• (i) acceptable coronary revascularization risk
  and suitable viable myocardium with left main
  stenosis
• (ii) three-vessel CAD in conjunction with left
  ventricular dysfunction
• (iii) two-vessel disease involving severe
  proximal left ant. Descending a. obx.
• (iv) intractable coronary ischemia despite
  maximal medical therapy
• ??? 4-6? ?? ??. ???? 6? ??? ???

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Pharmacological treatment
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Beta-blocker
Pharmacological treatment

• Rationale for the use of perioperative ß-blocker
  therapy
• ??? anti-arrhythmic, anti-inflammatory, altered
  gene expression and receptor activity, protection
  against apoptosis
• ??? reduces post-myocardial
• infarction mortality
• reducing myocardial oxygen
• consumption
• Activation of hypothalamus-pituitary-adrenal axis
  ??? ??? 1??

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Beta-blocker
Pharmacological treatment

• Atenolol, bisoprolol
• ??? 2?? ??? ??
• Risk reduction???
• ??? ?? ?? ??? ??
• Thoracic epidural, a2-adrenergic agonists?? ????
  ??? ?? ?? ??
• (bradycardia, hypotention)

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Beta-blocker
Pharmacological treatment

• Thoracic epidural, a2-adrenergic agonists?? ????
  ??? ?? ?? ?? (bradycardia, hypotention)
• ?-blocker??? ? ???? ????
• ????? ?? 1????. ??? premedi?
• ??? HR? 50-60bpm?? ??
• ???? 80bpm? ?? ???
• ?? ??? 1?, ?? ?? ??
• ??? ?? ???? withdrawal Sx.
• ??? ????
• ?????? terget rate?? ???? ??? ???

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Beta-blocker
Pharmacological treatment

• ACC/AHA Class I guidelines
• (i) the need for ß-blockers in the recent past to
  control symptoms of angina
• (ii) patients with symptomatic arrhythmias or
  hypertension
• (iii) patients at high risk for a perioperative
  cardiac event based on the finding of myocardial
  ischemia on perioperative testing

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Beta-blocker
Pharmacological treatment

• ?-blocker? CIx
• Symptomatic bradycardia(lt50-60bpm)
• Symptomatic hypotension(lt90-100mmHg)
• Severe heart failure requiring i.v. diuretics or
  inotropes
• Cardiogenic shock
• Asthma or reactive airway disease requiring
  bronchodilator and/or steroids
• 2 or 3 degree AV block

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Alpha-2 adrenoceptor agonists
Pharmacological treatment

• Clonidine
• 0.2mg orally
• Reduced perioperative myocardial ischemia and
  improved 30-day and 2-yr mortality
• But had no effect on PMI
• Inhibit central sympathetic discharge, reduce
  peripheral norepinephrine release, and dilate
  post-stenotic coronary vessels

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Aspirin
Pharmacological treatment

• Improved outcome following CAB surgery
• Eliminates the diurnal variation in plaque
  rupture
• Anti-inflammatory effect

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Statins
Pharmacological treatment

• Lipid-lowering therapy
• Plaque size?
• Pleiotropic effects
• Reversal of endothelial dysfunction
• Modulation of macrophage activation
• Immunological effects
• Anti-inflammatory, antithrombotic and
  antiproliferative actions

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Conclusions

• PMI? etiology? ????
• High risk group??? ?? long-term outcome? ???? ??
  ??? ? ????? ???? ?
• ??, ??, ?? ??? ??? ??
• ????? ?????? ?