Download Ischemic heart disease MGMC 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
• IHD is vast
• Non cardiac surgery is an ocean
• Just I am going to touch some points
Preoperative workup
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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
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H/o Dyspnoea
oedema
H/o of M.I ,
F/H/O CAD
Co morbid conditions
current medications
Physical examination
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Look for cyanosis, pallor,
dyspnea during conversation,
nutritional status,
skeletal deformities,
tremors & anxiety,
assessment of vital signs ,
JVP pulsation, carotid bruit, oedema.
MET
3.5 ml/kg/min.
MET Functional Levels of Exercise
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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
12 Lead ECG
ECG
(Preoperative resting)
• Q waves
– Magnitude & extent
– Estimate of LVEF & long term mortality
• ST segment depression
Adverse
– Horizontal/downsloping > 0.5mm perioperative
cardiac events
• LVH with “strain pattern”
• LBBB with established IHD
Within 30 days of surgery, Both Preop. & Postop. ECG
Anteroseptal
ST elevation
Q waves (V1 – V4)
ST depression I, V3 – V6
LV strain pattern
Leads I, aVL, V4-V6
T wave inversion
LBBB
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 %
• IIICCC
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
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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 vasodilator
Dipyrimadole/Adenosine Thallium 201 imaging
– Dobutamine stress echocardiography
Increase 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
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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
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MI within 6 months,
Age>70
Emergency
AS, arrhythmias S3 gallop, increased JVP
Don’t think operation or not !!
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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,
• digoxin
• adenosine,
amiodarone
Beta blockers
lignocaine
Cardioversion
Myocardial oxygen balance
DECREASE O2 SUPPLY
Decreased CBF
tachycardia
hypotension
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 ??
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High spinal
Pancuronium
Pethidine
Ketamine
Etomidate
Benzodiazepines
Remifentanyl
Phenylephrine
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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
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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
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Hypoxemia
Shivering
Pain
-sepsis, bleeding-------Monitoring , enzymes
Summary
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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