Ischemic heart disease for noncardiac surgery

1. Ischemic heart disease for noncardiac surgery Dr. S. Parthasarathy MD., DA., DNB, MD (Acu), Dip. Diab. DCA, Dip. Software statistics, PhD(physiology) Mahatma Gandhi Medical College and Research Institute, Puducherry, India

2. IHD is vast • Non cardiac surgery is an ocean • Just I am going to touch some points

3. Preoperative workup • history, • physical examination, • investigation, • clinical risk predictors, • risk assessment, • functional capacity.

4. Preoperative workup • Who should do ?? • Wait for clearance is ??? • We should do !!

5. History • 1. Angina at unaccustomed work. No limitation of physical activity • 2. Angina on moderate exertion. Mild limitation of physical activity • 3. Angina on mild exertion. Marked limitation of physical activity • 4. Angina at rest • NYHA grades

6. history • H/o Dyspnoea • oedema • H/o of M.I , • F/H/O CAD • Co morbid conditions • current medications

7. Physical examination • Look for cyanosis, pallor, • dyspnea during conversation, • nutritional status, • skeletal deformities, • tremors & anxiety, • assessment of vital signs , • JVP pulsation, carotid bruit, oedema.

8. MET 3.5 ml/kg/min.

9. MET Functional Levels of Exercise • 1 Eating, working at a computer, dressing • 2 Walking down stairs or in your house, cooking • 3 Walking 1-2 blocks • 4 gardening • 5 Climbing 1 flight of stairs, dancing, bicycling • 6 Playing golf, carrying clubs • 7 Playing singles tennis • 8 Rapidly climbing stairs, jogging slowly • 9 Jumping rope slowly, moderate cycling • 10 Swimming quickly, running or jogging briskly • 11 Skiing cross country, playing full-court basketball • 12 Running rapidly for moderate to long distances

10. METS • < 4 • 4 - 7 • > 7

11. Vital point • Elective surgery in patients with a history of AMI should be delayed up to 6months after the episode of AMI if possible.

12. Investigations • All routine investigations • ECG and special

13. ECG 12 Lead ECG(Preoperative resting) • Q waves • Magnitude & extent • Estimate of LVEF & long term mortality • ST segment depression • Horizontal/downsloping> 0.5mm • LVHwith “strain pattern” • LBBBwith established IHD Adverse perioperative cardiac events Within 30 days of surgery, Both Preop. & Postop. ECG

14. Anteroseptal ST elevation Q waves (V1 – V4) LV strain pattern ST depression I, V3 – V6 LVH + ST dep. Leads I, aVL, V4-V6

15. T wave inversion LBBB Broad QRS complex

16. Certain terminologies

17. Revised cardiac risk index (Lee) • High-risk surgery (intraperitoneal, intrathoracic, or suprainguinal vascular procedures) • IHD • History of congestive heart failure   •  History of cerebrovascular disease    • Diabetes mellitus requiring insulin  • Creatinine >2.0 mg/dL • 0 = 0.4%, 1 = 0.9%, 2 = 7%, >3 = 11 % • I II C CC

18. Surgical risk • High(Cardiac risk often >5%) • Emergency surgery (specially in elderly) • Aortic/majorvascular/peripheral vascular surgery • Major surgerywith large fluid shifts/bloodloss • Intermediate (Cardiac risk generally <5%) • Carotid endarterectomy, Head & neck • Intraperitoneal, Intrathoracic, Ortho, Prostate • Low(Cardiac risk generally <1%) • Superficial procedure, Cataract, Endoscopy, Breast

19. Clinical Predictors of Increased Perioperative Cardiovascular Risk

20. Physical capacity • Surgery • Cardiac risk index • Clinical predictors • Three sentences to follow !!

21. Perioperative risk with non vascular surgery, non high risk is low • Chronic stable angina 4 - METs • Revascularization 5 years prior with stable symptoms • Is there a need for evaluation ??

23. Preoperative exercise stress testing?? • Preoperative exercise stress testing is usually not indicated in patients • with stable coronary artery disease and acceptable exercise tolerance. • Because the exercise ECG can produce a number of false-negative and false-positive results, its predictive value is limited.

24. Investigations • Exercise ECG • Patients unable to exercise • Radionuclide Myocardial Perfusion Imaging Induce hyperaemic response: Coronary vasodilator Dipyrimadole/Adenosine Thallium 201 imaging • Dobutamine stress echocardiography Increase myocardial O2 demand: Dobutamine • Cardiac CT • Echocardiography

25. Induced Ischaemia • ST segment depression • Horizontal or downsloping > 0.1 mV • ST segment elevation • >0.1 mV in noninfarct lead • Abnormal leads: 5 or more • Ischaemic response • Persistent > 3 min after exertion • Typical angina • Exercise induced fall in Syst. BP by 10 mmHg

26. ECHO • Size of chambers • Dimension/volume of cavity • Wall thickness • Pumping function • Ejection fraction • Regional wall motion abnormalities • Hypokinesia, Dyskinesia, Akinesia • Valve function • Diastolic dysfunction

27. Cardiac CT Reconstruction

28. Dobutamine stress echocardiography • RWMA at 60 % predicted heart rates – cardiac risk • Myocardial perfusion imaging • More than 20 % defect • Reversible – more dangerous

29. Medications • Beta blockers • Statins • Alpha agonists • Smoking cessation, hypertension, diabetic control • Diuretics , antiplatelets – case to case • Nitroglycerines

30. Anti platelets • Aspirin (Low dose) • Cardiovascular risk > Bleeding risk – continue • Prostatectomy & Intracranial surgery- discontinue • Clopidogrel (Elective Surgery) • With hold for 1 week • If cardiac risk high: LMWH • Dual therapy/Emergency surgery • Platelet transfusions • Haemostatic agents

31. Preoperative PCI • The indications don’t change with surgery or not

32. innumerable protocols

37. Goldman risk index • MI within 6 months, • Age>70 • Emergency • AS, arrhythmias S3 gallop, increased JVP

38. Don’t think operation or not !! • Do we need investigations • Do we need PCI • Do we need CABG • Does not change much !! • Beta blockers, statins , alpha agonists, Ca C inh, digitalis to continue • Warfarins ?? And LMWH

39. Intraoperative management • ST segment monitoring and analysis (II, V4,V5 – 96%) • Temperature Core temperature >35OC • Blood sugar control (Insulin) <150 mg% • CVP ?? Arterial line – case to case basis , PAC ?? • Risk of major haemodynamic disturbances • TEEEmergency use three times as ECG, looking like a cell phone – preintubation ?? • Acute, persistent haemodynamic instability

40. ECG • The introduction of ST-segment trending helps as an early warning detection system but should not replace examination of the ECG printout. • 15 % - 40 % changes

41. Perioperativearrythmias • no details • SVT VT sustained or not • Ca channel blockers, Beta blockers • digoxinlignocaine • adenosine, amiodaroneCardioversion

42. Myocardial oxygen balance DECREASE O2 SUPPLY INCREASED O2 DEMAND Tachycardia Increased wall tension ↑ preload ↑ afterload Increased contractility Decreased CBF tachycardia hypotension increased preload hypocapnia ↓ Oxygen content anemia Hypoxemia decreased release – ODC - Lt

44. Anaesthetic technique • Regional block • Better ablation of catecholamine response • Decreases preload and afterload • Less hypercoagulable state • Limit use to infra-umbilical procedures • Volatile anaesthetics (Maintenance) • Beneficial (In haemodynamically stable) • Cardioprotective: Decrease troponin release • Pre & Post condition against infarction • N2O – increased PVR, DD, homocysteine increase

45. Anaesthetic technique • Subarachnoid block • Bupivacaine + Fentanyl • General Anaesthesia + Epidural • Monitored anaesthesia care • L.A + Intravenous sedation/analgesia • Ensure satisfactory local anaesthetic block • Dexmedetomidine (short acting  2 agonist)

46. Can we have ?? • High spinal • Pancuronium • Pethidine • Ketamine • Etomidate • Benzodiazepines • Remifentanyl • Phenylephrine • iVlignocaine • Smooth extubation • Atropine • Atracurium • Vecuronium • mivazerol (IV form only available in Europe)

47. Nitroglycerin • Role unclear • Intravenous NTG • Compounds vasodilation (Anaesthetics) • Cardiovascular decompensation • Monitor intravascular status (CVP) • Topical NTG • Uneven absorption • Ischemia detected – other drugs ?? – then use

48. Predictors of postoperative myocardial ischaemia • Left ventricular hypertrophy • History of hypertension • Diabetes mellitus • Known ischaemic heart disease • Use of digoxin • 8 -24 hours , upto 40 % of high risk patients • Previous !!

49. Postoperative period • Say No to • Hypoxemia • Shivering • Pain • -sepsis, bleeding-------- • Monitoring , enzymes

50. Summary • METs • Risk index • Surgical • Drugs , IHD and anaesthetic • SA or GA – monitoring • Maintain balance • Post op – say no to ??