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Perioperative Myocardial Infarction - Etiology and Prevention

Perioperative Myocardial Infarction - Etiology and Prevention. R3 김상영. PMI. Predictor of short- and long-term morbidity and mortality 예방을 위해 etiology 를 잘 알아야 함 Etiology : 명확하게 밝혀지지 않음 여러요소가 관련됨 계속 논의중인 영역.

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Perioperative Myocardial Infarction - Etiology and Prevention

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  1. Perioperative Myocardial Infarction- Etiology and Prevention R3 김상영

  2. PMI • Predictor of short- and long-term morbidity and mortality • 예방을 위해 etiology를 잘 알아야 함 • Etiology : 명확하게 밝혀지지 않음 여러요소가 관련됨 계속 논의중인 영역

  3. Etiology of PMI

  4. Etiology of PMI Acute Coronary Syndrome • Etiology • 관련인자 : plaque(structurally&functionally), 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

  5. Etiology of PMI Acute Coronary Syndrome • Pathophysiology • Plaque progression • abrupt, unpreditable 종종 thrombosis발생에 관여 • Risk factors & triggers : physical activity, mental stress, environmental temperature, smoking, infection, hydration, arterial pr.

  6. Etiology of PMI Acute Coronary Syndrome • 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↑⇒ 응고경향↑ ⇒ torombosis↑ 수술중 환경과 비슷!!

  7. Etiology of PMI Acute Coronary Syndrome • 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 • 시간지날수록 size 커짐

  8. Etiology of PMI Perioperative MI • Etiology • 여러 요소들이 복합적으로 작용한다는 개념 (CAG, EKG, oxygen supply/demand mismatch, plaque rupture) • Most(>80%) PMIs occur early after surgery • Asymptomatic, non-Q-wave type • ST-seg depression(duration이 중요) • Serum troponin concentration • HR의 증가가 동반되기도 • Prolonged stress-induced myocardial ischemia → primary cause of PMI!!

  9. Etiology of PMI Perioperative MI • 수술끝날무렵, 깨울때 잘 생김 (HR↑, a.pr. ↑, sympathetic tone↑, procoagulant activity↑) • 기존에 CAD있으면 plaque에 의하지 않아도 coronary a. thrombosis유발가능 • Plaque disruption • Thrombosis와 thrombolysis간에 균형, 충분한 flow condition

  10. Etiology of PMI Perioperative MI • 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

  11. Etiology of PMI Perioperative MI • 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

  12. Etiology of PMI Perioperative MI • High specificity of cardiac troponin • MI & Troponin concentration • cTnI > 1.5 ng ml & cTnT > 0.1 ng ml • Cardiac troponin이 CK-MB보다 더 적합 • 전통적 정의 ⇒ underestimate troponin을 이용한 정의 ⇒ overestimate • Long term survival rate에 영향 • 소량의 증가도 유의한 결과로 받아들여야

  13. Prevention of Perioperative MI

  14. Prevention of perioperative MI Preoperative Coronary Revascularization 지지자측 : improve perioperative and long- term outcome 반대자측 : 시술자체의 risk, 시술후의 수술 시 기에 따른 예후

  15. Prevention of perioperative MI Preoperative Coronary Revascularization • Preoperative coronary angiography • Positive DTS pts.에서 시행 • Perioperative cardiac outcome향상 • Cardiac evaluation중에 MI 2명, death 3명 • 통계적으로 유의한 결과 없었음 • 결론 : 유익한 추가정보를 주거나 이익을 준다고 생각되지 않음

  16. Prevention of perioperative MI Preoperative Coronary Revascularization • Percutaneous transluminal coronary angioplasty (PTCA) • 자료의 크기와 design이 적절하지 않음 • 후향성 연구에서는 효과가 있다고 나옴 • Angina pectoris & congestive heart failure↓ but not in non-fatal PMI & mortality • 시술 90일 후에는 유의한 유익 없음

  17. Prevention of perioperative MI Preoperative Coronary Revascularization • Coronary stenting • Fatal cardiac event의 원인 : stent thrombosis • 시술후 6주 이내에 수술한 그룹에서 발생 • 7~9주 후에 수술한 그룹에서는 없었다

  18. Prevention of perioperative MI Preoperative Coronary Revascularization • Preoperative surgical coronary revascularization • 수술전에 CABG시행한 그룹이 PMI와 mortality에서 향상된 값을 보임 • Advanced angina & multi-vessel CAD에서 특히 뚜렷 • Minor op.시에는 차이점 없었다 • CABG시행 후 1달이내에 수술한 그룹에서 MI↑, mortality↑ • 6개월 뒤에 수술 권장

  19. Prevention of perioperative MI Preoperative Coronary Revascularization • Risk calculation in preoperative coronary revascularization • 시술 자체의 risk를 배제했던 결과들 • 모두 감안하면 오히려 총 risk가 높아질 수 있다 • 수술만 놓고 보면 수술 단독군이 risk가 적다 • Long-term outcome까지 고려해야 함 (추후에 시술을 받을 가능성이 얼마인지)

  20. Prevention of perioperative MI Preoperative Coronary Revascularization • Recommendations for preoperative coronary angiography • 수술예정이 아닌 환자와 비슷한 Ix을 적용 • 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

  21. Prevention of perioperative MI Preoperative Coronary Revascularization • Recommendation for preoperative coronary intervention • 수술과 관계없는 환자와 비슷하게 적용 • PTCA • Balloon plasty한 자리가 다 아문뒤에 수술하는 것이 좋다 (적어도 일주일 뒤)

  22. Prevention of perioperative MI Preoperative Coronary Revascularization • Coronary stenting • Dual antiplatelet medication (thienopyridine & aspirin) • Re-endothelialization (대략 8주) • Re-stenosis (대략 6-8주) • 수술연기 : 절대적으로 2주 4-6주가 적당 • Drug-eluting stent : stent stenosis가능성↑, antipletelet 복용기간↑ 수술 몇 달 연기하는게 낫다 • 2달이내 수술이 필요한 경우 • Dual antipletelet therapy를 surgeon이 인정하면 drug-eluting stent도 가능

  23. Prevention of perioperative MI Preoperative Coronary Revascularization • 2달이내 수술이 필요한 경우 • Dual antipletelet therapy를 surgeon이 인정하면 drug-eluting stent도 가능 • 인정 안하면 heparin-or phosphorylcholine-coated stent이용이 효과적 • PTCA without stent placement

  24. Prevention of perioperative MI Preoperative Coronary Revascularization • Recommendation for preoperative surgical coronary revascularization • 역시 수술안하는 사람과 유사한 Ix적용 • 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 • 적어됴 4-6주 뒤에 수술. 가능하면 6달 이후가 바람직

  25. Pharmacological treatment

  26. Pharmacological treatment Beta-blocker • Rationale for the use of perioperative β-blocker therapy • 장점들 : anti-arrhythmic, anti-inflammatory, altered gene expression and receptor activity, protection against apoptosis • 효과들 : reduces post-myocardial infarction mortality reducing myocardial oxygen consumption • Activation of hypothalamus-pituitary-adrenal axis : 수술후 적어도 1주일

  27. Pharmacological treatment Beta-blocker • Atenolol, bisoprolol • 퇴원후 2년내 유병률 비교 • Risk reduction있었다 • 실험에 대해 여러 비판도 존재 • Thoracic epidural, α2-adrenergic agonists과의 병용치료 여부에 대해 검증 미비 (bradycardia, hypotention)

  28. Pharmacological treatment Beta-blocker • Thoracic epidural, α2-adrenergic agonists과의 병용치료 여부에 대해 검증 미비 (bradycardia, hypotention) • Β-blocker약제는 뭘 선택해도 무방하다 • 시작시기는 수술 1주전부터. 늦어도 premedi시 • 수술중 HR을 50-60bpm으로 조절 술후에도 80bpm을 넘지 않도록 • 술후 적어도 1주, 보통 한달 복용 • 갑자기 투여 중지하면 withdrawal Sx. 서서히 감량해야 • 집중관찰하여 terget rate에서 조절해야 효과가 있었다

  29. Pharmacological treatment Beta-blocker • ACC/AHA Class I guidelines • (i) the need for β-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

  30. Pharmacological treatment Beta-blocker • Β-blocker의 CIx • Symptomatic bradycardia(<50-60bpm) • Symptomatic hypotension(<90-100mmHg) • 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

  31. Pharmacological treatment Alpha-2 adrenoceptor agonists • 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

  32. Pharmacological treatment Aspirin • Improved outcome following CAB surgery • Eliminates the diurnal variation in plaque rupture • Anti-inflammatory effect

  33. Pharmacological treatment Statins • Lipid-lowering therapy • Plaque size↓ • Pleiotropic effects • Reversal of endothelial dysfunction • Modulation of macrophage activation • Immunological effects • Anti-inflammatory, antithrombotic and antiproliferative actions

  34. Conclusions • PMI의 etiology는 다방면성 • High risk group환자의 경우 long-term outcome을 고려하여 술전 시술이 더 유익한지를 판단해야 함 • 술전, 술중, 술후 약제를 이용한 관리 • 집중적으로 모니터링해야 함

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