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