1. Preoperative Cardiac Evaluation
Prepared for KMRH residents in Anaesthesia July 2013
Kabul

2. Preoperative Cardiac Evaluation
Risk assessment – Patient and Surgical Factors
Pre-operative Interventions to modify risk
Intra-operative Interventions to modify risk
Post Operatively Surveillance

3. Preoperative Cardiac Evaluation
Risk assessment : Patient Factors
Congestive Heart Failure
MI within 30 days
Severe Cardiac Arrhythmia including heart block
Severe Valvular disease
Severe or Unstable angina
Other - Remote MI, Diabetes, Renal dysfunction, Poorly managed hypertension, Rhythm other than sinus, Previous or compensated CHF, stable angina
treated hypertension, LVH or LBBB, advanced age

4. Preoperative Cardiac Evaluation Patient Factors
Congestive Heart Failure
MI within 30 days
Severe Cardiac Arrhythmia including heart block
Severe Valvular disease
Severe or Unstable angina
These are severe clinical indicators
and patients should be evaluated
and optimized preoperatively

5. Preoperative Cardiac Evaluation Patient Factors
Other - Remote MI, Diabetes, Renal dysfunction, Poorly managed hypertension, Rhythm other than sinus, Previous or compensated CHF, stable angina
These are intermediate clinical indicators
that may or may not need further evaluation
depending on their functional capacity and
nature of surgery.

6. Preoperative Cardiac Evaluation Patient Factors
Functional capacity – is the patient able to :
Class I – Angina only during strenuous or METS
prolonged physical activity
Class II – Slight limitation, with angina only METS
during vigorous physical activity
Class III –Symptoms with everyday living 4-6 METS
activities, i.e., moderate limitation
Class IV – Inability to perform any activity < 4 METS
without angina or angina at rest,
i.e.,severe limitation

7. Cardiac Risks of Noncardiac Surgery Surgical Factors
Cardiac stress is inherent to surgery
Anaesthetic technique, drugs, pain, and nature of the Surgery all effect :
1. The stress response and catecholamines – increase HR and BP
2. Fluctuations in HR, BP, intravascular volume, oxygenanation, and oxygen transport
These factors will cause imbalance in myocardial O2 supply and
demand
Inhalational agents cause afterload reduction, decreased contractility. Spinal anesthesia causes sympathetic blockade with decrease in preload and afterload, fluid shifts.

8. Cardiac Risks of Non-cardiac Surgery
Myocardial Oxygen Supply and Demand
increased HR decreased HR
increased Systolic BP increased Diastoloic BP
increased wall tension reduced wall tension
increases chamber pressure decreased chamber pressure
adequate coronary circulation inadequate coronaries adequate hemoglobin
Supply Supply

9. Surgery-specific risks
High risk (>5% cardiac risk)
Emergency major operations
Especially in the elderly
Aortic or major vascular surgery
Extensive operations with large volume shifts or blood loss.

10. Surgery-specific risks
Intermediate risk (<5% cardiac risk)
Intraperitoneal and intrathoracic
Carotid endarterectomy
Head and neck
Orthopedic
Prostate

11. Surgery-specific risks
Low risk surgeries (<1% cardiac risk)
Endoscopic procedures
Superficial biopsies
Cataracts
Breast surgery

12. Assessing the situation
Determine the urgency for surgery
Emergency Surgery – few options – do the best you can
Options to consider (as a team)
Postpone or cancel
Modify the surgical procedure
Delay case (for further testing or patient optimization)
Perioperative medical therapy
Perioperative monitoring
Modification of the location of care
This is often done for us.
Hence, this presentation deals largely with the elective or semi-urgent surgery, during which time the case may be considered and options explored.
However, one may be called upon even in the emergent setting. In this case, the consultant in medicine should focus on perioperative medical management, surveillance, and post-operative risk stratification

13. Pre-operative Interventions to Modify Risk Investigations
EKG – suitable for most patients over 40 with risk factors
CXR - if any concern from history or physical examination
Bloodwork – if significant co-morbidities or chance of significant blood loss
Consultation – changing nature of symptoms ( eg worsening angina ) or concern regarding valvular integrity or ventricular function
Testing may include echocardiography or cardiac stress testing
Medications may be adviseable – B blockers, statins, ASA, others
Invasive intervention should be based on symptoms, not surgery

14. Intra-operative Interventions to Modify Risk
Consider :
Anaesthetic Technique
Intra operative Monitoring
Choice of Drugs
Post operative analgesia
Post operative care

15. Intra-operative Interventions to Modify Risk: Anaesthetic Technique
Regional Anaesthesia –
Minimizes the hormonal stress response
Spinal/Epidural techniques require consideration of hemodynamic changes
Never been shown superior or safer to GA
Some benefit to graft patency for peripheral vascular surgery

16. Intra-operative Interventions to Modify Risk: Choice of Drugs
Optimization of myocardial O2 supply/demand is the goal !!!
B blockers pre or intra operatively may reduce incidence of adverse cardiac events , may increase risk of cerebrovascular events
All volatiles (except N2O) are vasodilators and reduce contractility – so they may reduce demand, but also reduce supply ! Some ( sevoflurane ) may have intrinsic cardio-protective effects
Vasopressors alpha agents ( neosynephrine ) may help increase coronary perfusion pressure and may be useful in conjunction with B blockers

17. Intra-operative Interventions to Modify Risk Choice of Drugs
Ketamine increases HR and contractility but may minimize post induction hypotension – consider combining it with midazolam to reduce unwanted effects
NTG enhances coronary perfusion but reduces BP and filling pressure
ACE inhibitors and Angiotensin receptor blockers
Beware as they may cause profound post induction hypotension unresponsive to sympathomimetics – may require small dose vasopressin (0.4 U)
Post op Analgesia will reduce the stress response if adequate. Consider multimodal approach including neuraxial opioids ( if appropriate monitoring available )

18. Intra-operative Interventions to Modify Risk: Monitoring
Invasive monitoring may assist in guiding fluid management, provide early warning to hemodynamic changes, and allow blood analysis
EKG additional leads ( 5 lead ) may allow detection of up to 70 % of ischemic events

19. Post Operative Surveillance
Post operative cardiac events
peak at 48 hrs post op
Myocardial infarctions are often silent with 50% mortality
CHF as a result of remobilization of intra-operative fluids
Consider intermediate care area for high risk patients

20. Preoperative Evaluation Algorithm Putting it all together

21. Preoperative Evaluation Algorithm Putting it all together
For patients with major clinical predictors undergoing non-emergent noncardiac surgery, consider delaying the surgery.
Medical management
Medical Risk factor modification
Consider invasive/non-invasive testing

22. Preoperative Evaluation Algorithm Putting it all together
For patients with intermediate clinical predictors, evaluate functional status.
Moderate to good functional status (>4 mets) promps us to look at the procedure itself.
Low functional status (<4 METs) may merit further testing.
High surgical risk  further testing
Intermediate or low surgical risk  likely okay to OR, with risk

23. Preoperative Evaluation Algorithm Putting it all together
For patients without intermediate clinical predictors, moderate to good functional status indicates lowest cardiac risk for all procedures
Poor functional status should always prompt us to evaluate the surgical procedure and consider further testing

24. Preoperative evaluation algorithm
Consider noninvasive testing if two or more are present:
Intermediate clinical predictors
Poor functional capacity
High surgical risk procedure

25. Therapeutic Preoperative Interventions at KMRH
Invasive options available ? ( PCTA, stents, CABG ) for severe symptoms
Medical optimization
Stress testing, Echocardiography may direct you to modify your anaesthetic plans

26. Thank You