Myocardial injury after non cardiac surgery (MINS.pptx

myocardial injury after non cardiac surgery

1. Myocardial Injury After Non Cardiac Surgery (MINS)

2. CONTENT INTRODUCTION DEFINITION PERIOPERATIVE CONSIDERATION PREOPERATIVE INTRAOPERATIVE POSTOPERATIVE

3. Introduction Cardiac complications are common after major non-cardiac surgery 30% of those having surgery procedure have at least 1 cardiovascular risk factor, with 30 day motality rate of 0.5% - 2% Major adverse cardiac event – MI The pathophysiology of MINS in surgical patients differs from that of myocardial infarction in medical. Surgical patients are exposed to a unique environment that includes sympathetic activation, bleeding, anaemia , pain, hypotension and hypercoagulability during the perioperative period.

4. Definition of myocardial ischaemia Tropinin rise above 99 th percentile with at least one of the following features: Ischaemic nature of chest pain Recent significant ECG findings such as new ST segment changes or left bundle branch block, or present of Q wave Echocardiography - New onset regional wall abnormality Angiography - intracoronary thrombus on Definition of myocardial ischaemia is difficult in the perioperative context. More than 93% of patients who experienced MINS, did not fulfil the diagnostic criteria for the universal definition of myocardial ischaemia Only 7% presented with ischaemic symptoms and 15% had nonspecific ECG changes. Most of post-operative MI (PMI) manifest without symptoms – GA/ post operative analgesia/ sedation  thus PMI often recognized late  high attributable mortality

5. Definition of MINS Post operative troponin level elevation during or within 30 days after non cardiac surgery with: Underlying ischaemic origin of troponin elevation – (exclusion of known non- ischaemic causes of perioperative troponin elevation, e.g. sepsis and pulmonary embolism) Absence of other clinical or ECG criteria of PMI

6. PHYSIOLOGY 2 mains mechanisms to cause myocardial ischaemia : Acute coronary artery rupture or instability Myocardial oxygen supply-demand imbalances Contributing factors: Increase myocardial oxygen demand from symptathetics response to pain/ trauma / inflammation Reduction in myocardial oxygen supply: anaemia / hypoxia/ hypotension / thrombosis from perioperative hypercoagulability

7. Preoperative considerations: Risk evaluation scoring systems Multiple scoring systems are available that predict risk of major adverse cardiac event Lee’s revised Cardiac Risk Index  predicts major cardiac complication in non cardiac surgery https://www.uptodate.com/contents/image?imageKey=CARD%2F57075&topicKey=PC

8. Mortality score in patient with MINS

9. Recent MI Recent PCI

10. STRESS TEST ESC/ESA/AHA/ACC guideline propose preop stress test if all the following criteria are met: Elective surgery Patient has poor functional capacity limited by angina or SOB, or with unknown functional capacity Patient has elevated perioperative risk of major adverse coronary events Testing will impact decision making for perioperative care Patient with excellent functional capacity (METs > 10) – no need stress test In patient with moderate to good functional status (4- 10 METs) – reasonable to forgo stress test and proceed with surgery

11. CORONARY REVASCULARISATION Unless strong indication; ex: left main stem disease, - preoperative prophylactic revascularization in stable or asymptomatic coronary artery disease has shown no benefit

12. Medication considerations Beta blockers Guideline suggest continuing beta blocker for those already taken them It is still debatable about starting pt who are at risk of perioperative myocardial ischaemia – increase mortality & stroke risk due to drug induced hypertension Aspirin Recent RCT showed and increased rate of significant bleeding without improved mortality / reduced non fatal MI ACE American guideline: suggest to continue their used European guidelines: suggest discontinuing the therapy

13. Statins Statin may reduce the incidence of perioperative MI Should be continued in pt already on them and could be initiated in patient undergoing vascular surgery at least 2 week preoperatively Clonidine an α2-adrenergic agonist that reduces blood pressure by inhibiting sympathetic outflow – did not prove beneficial

14. Intraoperative consideration

15. Myocardial supply demand imbalance can be modified intraoperatively to prevent myocardial ischaemia Component Oxygen Maintain normal oxygen saturation using lowest possible FiO2 Hyperoxia can increase infarct size in acute STEMI Significant association between high FiO2 and ACS Heart rate Large dose of perioperative heart rate reducing agents given preoperatively have not proved to be beneficial Avoiding tachycardia with careful titration of analgesia and beta blockers Transfusion treshold Hb > 10 might result in better outcome for pt with ACS In low risk gp : hb of 8 Temperature control Hypothermia associated with increased perioperative myocardial ischaemia and cardiac event

16. Anaesthetic technique There is no strong evidence to support a specific anaesthetic technique in preventing myocardial ischaemia Volatile compare with TIVA – inconclusive Use of Nirous oxide – does not appear to increase mortality COX 2 inhibitor – increase risk of MI

17. Intraoperative monitoring

18. Post operative consideration Postoperative placement – consider move to more intensive monitoring Serial ECGs/ Tropinoin level Ensure cardiology follow up or in patient review if infarct is suspected Ensure good analgesic, euvoleamia Maintain normal oxygen saturation Commence aspirin and PGY2 inhibitor as guided by cardiology opinion

19. Management of myocardial ischaemia Confirm diagnosis Obtain 12 ECG lead Obtain baseline and 4 hour troponin levels Optimise myocardial oxygen supply and demand balance Consider Abandoning surgery