Ischemic heart disease for noncardiac surgery Dr. S. Parthasarathy MD., DA., DNB, MD (Acu), Dip....

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

• IHD is vast

• Non cardiac surgery is an ocean

• Just I am going to touch some points

Preoperative workup

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

Preoperative workup

• Who should do ??

• Wait for clearance is ???

• We should do !!

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

history

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

Physical examination

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

MET3.5 ml/kg/min.

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

METS

• < 4

• 4 - 7

• > 7

Vital point

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

Investigations

• All routine investigations

• ECG and special

ECG12 Lead ECG(Preoperative resting)

• Q waves– Magnitude & extent – Estimate of LVEF & long term mortality

• ST segment depression– Horizontal/downsloping > 0.5mm

• LVH with “strain pattern”• LBBB with established IHD

Adverseperioperativecardiac events

Within 30 days of surgery, Both Preop. & Postop. ECG

Q waves (V1 – V4)

AnteroseptalST elevation

ST depression I, V3 – V6 LV strain pattern

Leads I, aVL, V4-V6LV

H + ST

dep.

T wave inversionLBBB

Broad QRS complex

Certain terminologies

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 I I C C C

Surgical risk

• High (Cardiac risk often >5%)– Emergency surgery (specially in elderly)– Aortic/major vascular/peripheral vascular surgery– Major surgery with large fluid shifts/blood loss

• Intermediate (Cardiac risk generally <5%)– Carotid endarterectomy, Head & neck – Intraperitoneal, Intrathoracic, Ortho, Prostate

• Low (Cardiac risk generally <1%)– Superficial procedure, Cataract, Endoscopy, Breast

Clinical Predictors of Increased Perioperative Cardiovascular Risk

• Physical capacity • Surgery • Cardiac risk index • Clinical predictors

• Three sentences to follow !!

• 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 ??

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.

Investigations• Exercise ECG• Patients unable to exercise

– Radionuclide Myocardial Perfusion Imaging Induce hyperaemic response:

Coronary vasodilatorDipyrimadole/Adenosine Thallium 201 imaging

– Dobutamine stress echocardiographyIncrease myocardial O2 demand: Dobutamine

• Cardiac CT• Echocardiography

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

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

Cardiac CT Reconstruction

• Dobutamine stress echocardiography• RWMA at 60 % predicted heart rates – cardiac

risk • Myocardial perfusion imaging• More than 20 % defect • Reversible – more dangerous

Medications

• Beta blockers • Statins • Alpha agonists• Smoking cessation, hypertension, diabetic

control • Diuretics , antiplatelets – case to case

• Nitroglycerines

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

Preoperative PCI

• The indications don’t change with surgery or not

innumerable protocols

Goldman risk index

• MI within 6 months, • Age>70• Emergency • AS, arrhythmias S3 gallop, increased JVP

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

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

• TEE Emergency use three times as ECG, looking like a cell

phone – preintubation ??

– Acute, persistent haemodynamic instability

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

Perioperative arrythmias

• no details

• SVT VT sustained or not

• Ca channel blockers, Beta blockers• digoxin lignocaine• adenosine,

amiodarone Cardioversion

Myocardial oxygen balance

DECREASE O2 SUPPLY Decreased CBF

tachycardiahypotension increased preload hypocapnia

↓ Oxygen content anemia

Hypoxemia decreased release – ODC - Lt

INCREASED O2 DEMAND • Tachycardia

• Increased wall tension ↑ preload ↑ afterload

• Increased contractility

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

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)

Can we have ??

• High spinal • Pancuronium • Pethidine • Ketamine • Etomidate • Benzodiazepines• Remifentanyl • Phenylephrine

• iV lignocaine • Smooth extubation• Atropine • Atracurium

• Vecuronium• mivazerol (IV form only

available in Europe)

Nitroglycerin

• Role unclear• Intravenous NTG

– Compounds vasodilation (Anaesthetics)– Cardiovascular decompensation– Monitor intravascular status (CVP)

• Topical NTG– Uneven absorption– Ischemia detected – other drugs ?? – then

use

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 !!

Postoperative period

• Say No to

• Hypoxemia • Shivering • Pain • -sepsis, bleeding--------• Monitoring , enzymes

Summary

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

Homework

• IHD - met 5 and hernioraphy

• IHD, PCI done for TURP

• CABG done on clopidogrel for DU perforation

• IHD with mild AS for DHS . 75 years male

Thank you all