Preoperative Cardiac Risk Assessment

Quick Answer

Exam Essentials - ANZCA Final Examination

Preoperative cardiac risk assessment identifies patients at risk of major adverse cardiac events (MACE) using validated tools and evidence-based strategies. Revised Cardiac Risk Index (RCRI): Six independent predictors of cardiac complications—high-risk surgery, ischaemic heart disease, heart failure, cerebrovascular disease, diabetes on insulin, and renal insufficiency (Cr >175 μmol/L). Risk stratification: RCRI 0-1 (low risk, <1% MACE), RCRI 2 (moderate risk, 1-5% MACE), RCRI ≥3 (high risk, >5% MACE). Functional capacity: Use Duke Activity Status Index (DASI) or metabolic equivalents (METs); ≥4 METs (climb flight of stairs) generally adequate for most surgery. Stepwise approach: (1) Identify active cardiac conditions requiring workup; (2) Determine surgical risk (low <1%, intermediate 1-5%, high >5%); (3) Assess functional capacity; (4) Calculate RCRI; (5) Apply stress testing algorithm if indicated. Evidence-based testing: No routine testing for low-risk surgery regardless of patient risk; stress testing reserved for high-risk surgery with poor functional capacity or multiple RCRI factors. Optimisation: Continue beta-blockers; avoid starting high-dose beta-blockers acutely; consider statin therapy; manage heart failure and arrhythmias. [PMID: 15817509, 18606420, 23429985]

Introduction

Preoperative cardiac risk assessment is a fundamental component of perioperative medicine, enabling anaesthetists to identify patients at risk of major adverse cardiac events (MACE), optimise medical management, and guide perioperative monitoring and resource allocation. Cardiac complications remain the leading cause of perioperative morbidity and mortality in non-cardiac surgery, with myocardial infarction, heart failure, and arrhythmias contributing significantly to prolonged hospitalisation, increased healthcare costs, and reduced long-term survival.

The Australian and New Zealand College of Anaesthetists (ANZCA) Professional Standard PS07 provides guidance on preoperative assessment, emphasising the importance of structured risk stratification and evidence-based decision-making regarding preoperative testing and optimisation. Understanding cardiac risk assessment is essential for ANZCA Fellowship candidates, as it forms the foundation of perioperative patient safety and resource stewardship.

Epidemiology and Significance

Burden of Perioperative Cardiac Complications

Cardiovascular complications represent the most significant cause of morbidity and mortality following non-cardiac surgery.

Incidence of Major Adverse Cardiac Events:

Perioperative myocardial infarction: 1-5% of high-risk surgical patients [PMID: 24128014]
Cardiac death: 0.5-2% in unselected surgical populations [PMID: 15817509]
Heart failure exacerbation: 2-8% in patients with pre-existing cardiac disease [PMID: 23429985]
Significant arrhythmias: 5-15% in high-risk patients [PMID: 24128014]

Risk Stratification by Surgery Type:

Surgical Risk Category	Cardiac Risk	Examples
Low risk	<1% MACE	Superficial procedures, cataract, breast, endoscopy
Intermediate risk	1-5% MACE	Intraperitoneal, intrathoracic, carotid, orthopaedic
High risk	>5% MACE	Aortic, major vascular, peripheral vascular

[PMID: 18606420]

Impact on Outcomes:

Perioperative myocardial infarction increases 30-day mortality 3-10 fold [PMID: 24128014]
Cardiac complications prolong hospital stay by 3-7 days on average [PMID: 23429985]
Patients experiencing MACE have reduced 1-year survival compared to those without events [PMID: 15817509]

Australian and New Zealand Context

Epidemiological Considerations:

Higher burden of cardiovascular disease in rural and remote populations
Indigenous populations experience 2-3 times higher rates of cardiac disease [PMID: 29024541]
Ageing surgical population with increasing prevalence of comorbidities
Growing complexity of ambulatory surgery requiring rapid risk stratification

Healthcare System Factors:

Limited access to cardiac testing in remote areas
Need for efficient assessment to maintain surgical throughput
Resource allocation based on evidence-based risk stratification
Telemedicine consultation for preoperative assessment in rural centres

Revised Cardiac Risk Index (RCRI)

Development and Validation

The Revised Cardiac Risk Index (RCRI), developed by Lee et al. in 1999 and subsequently validated in multiple populations, remains the most widely used and validated risk stratification tool for perioperative cardiac complications.

Original Derivation Study:

Prospective cohort of 4,315 patients ≥50 years undergoing major non-cardiac surgery [PMID: 10522955]
Identified six independent predictors of major cardiac complications
Simplified scoring system with excellent discriminative ability (c-statistic 0.81)
Validated in subsequent studies with consistent performance

RCRI Components and Scoring

Risk Factor	Definition	Points
High-risk surgery	Suprainguinal vascular, intraperitoneal, intrathoracic	1
Ischaemic heart disease	History of MI, positive stress test, angina, nitrate use, ECG with Q waves	1
Congestive heart failure	History of CHF, pulmonary oedema, paroxysmal nocturnal dyspnoea, S3, CXR showing pulmonary vascular redistribution	1
Cerebrovascular disease	History of TIA or stroke	1
Diabetes mellitus	On insulin therapy	1
Renal dysfunction	Creatinine >175 μmol/L (>2 mg/dL) or CrCl <30 mL/min	1

Risk Categories and Event Rates:

RCRI Score	Risk Category	Cardiac Risk	30-Day MACE Rate
0	Very low	<1%	0.4-0.5%
1	Low	<1%	0.9-1.3%
2	Moderate	1-5%	3.6-4.0%
≥3	High	>5%	9-11%

[PMID: 10522955, 15817509, 18606420]

Limitations and Considerations

Strengths:

Simple, clinically accessible scoring system
Validated in diverse surgical populations
Predicts cardiac death, myocardial infarction, and cardiac arrest
Guides decisions regarding monitoring intensity and ICU admission

Limitations:

Does not include age as a variable (older versions did)
May underestimate risk in contemporary populations with improved medical therapy
Does not account for functional capacity or specific surgical procedures
Less accurate in vascular surgery populations
Does not incorporate biomarkers (BNP, troponins)

Updates and Modifications:

Gupta Perioperative Risk Model (NSQIP MICA) incorporates age and surgical risk more precisely [PMID: 21616790]
Addition of preoperative BNP or NT-proBNP improves predictive accuracy [PMID: 24128014]
Revised criteria for renal dysfunction (Cr >265 μmol/L associated with higher risk)

Functional Capacity Assessment

Metabolic Equivalents (METs)

Functional capacity, expressed in metabolic equivalents (METs), is a critical component of cardiac risk assessment and often more predictive than stress testing results.

Definition of 1 MET:

Resting oxygen consumption at rest
Approximately 3.5 mL O₂/kg/min
Equivalent to sitting quietly

Activity Equivalents:

MET Level	Activity Example	Clinical Significance
1-2 METs	Eating, dressing, walking around house	Poor functional capacity—high cardiac risk
3-4 METs	Walking 2-3 km/h, golf (with cart), light housework	Marginal capacity—intermediate risk
4-6 METs	Climbing flight of stairs, walking 6 km/h, dancing	Good capacity—low cardiac risk
>6 METs	Running, swimming, tennis, skiing	Excellent capacity—minimal cardiac risk

[PMID: 23429985]

Clinical Significance:

≥4 METs: Generally adequate functional capacity for most surgical procedures without further cardiac testing
<4 METs: Poor functional capacity—indication for stress testing if undergoing high-risk surgery
Unknown functional capacity: Treat as poor capacity if unable to obtain reliable history

Duke Activity Status Index (DASI)

The DASI provides a standardized method to estimate functional capacity through a 12-item questionnaire.

Scoring System:

Self-care activities (eating, dressing, bathing): 1-2 METs each
Walking indoors, light housework: 2-3 METs
Climbing stairs, walking 6 km/h: 4-5 METs
Heavy housework, gardening: 5-6 METs
Strenuous sports: >7 METs

Calculation:

Each "yes" response receives weighted score
Total DASI score converted to predicted METs using formula: METs = (0.43 × DASI) + 9.6
Example: DASI score of 20 = approximately 18 METs predicted

Clinical Application:

DASI ≥34 predicts ≥7 METs (excellent functional capacity)
DASI <25 suggests <4 METs (poor functional capacity)
Particularly useful in elderly or sedentary patients where activity history is unclear

Cardiopulmonary Exercise Testing (CPET)

CPET provides objective measurement of functional capacity and cardiopulmonary reserve.

Key Parameters:

VO₂ peak: Peak oxygen consumption; <15 mL/kg/min associated with high perioperative risk
Anaerobic threshold: VO₂ at which lactate accumulates; <11 mL/kg/min predicts complications
VE/VCO₂ slope: Ventilatory efficiency; elevated values suggest heart failure
O₂ pulse: Cardiac output proxy; plateau suggests cardiac limitation

Risk Stratification by VO₂ Peak:

VO₂ Peak	Risk Category	Perioperative Risk
>20 mL/kg/min	Excellent	Minimal risk
15-20 mL/kg/min	Good	Low-moderate risk
10-15 mL/kg/min	Poor	Moderate-high risk
<10 mL/kg/min	Very poor	High risk; reconsider surgery

[PMID: 23609120]

Indications for CPET:

Complex major surgery in high-risk patients
Discordance between functional history and clinical assessment
Evaluation of unexplained dyspnoea
Preoperative optimisation before high-risk procedures

Preoperative Cardiac Testing

Stress Testing Algorithms

Evidence-based stress testing is guided by surgical risk, functional capacity, and RCRI score according to the AHA/ACC and ANZCA guidelines.

Stepwise Approach to Testing:

Low-risk surgery (<1% MACE):
- No routine cardiac testing regardless of patient risk
- Proceed to surgery with standard monitoring
Elevated risk surgery (≥1% MACE) with good functional capacity (≥4 METs):
- No routine cardiac testing
- Proceed to surgery
Elevated risk surgery with poor/unknown functional capacity (<4 METs):
- Assess RCRI and clinical risk factors
- If RCRI ≤1: May proceed to surgery without testing
- If RCRI ≥2: Consider stress testing
High-risk surgery with poor functional capacity and multiple risk factors:
- Stress testing indicated
- Choice of test depends on patient characteristics and local expertise

[PMID: 23429985, 24128014]

Stress Testing Modalities

Pharmacological Stress Testing (Preferred in Anaesthesia Context):

Test	Agent	Mechanism	Indications	Contraindications
Dobutamine stress echo	Dobutamine	Inotropic/chronotropic stimulation	Asthma, COPD, severe hypertension	Arrhythmias, severe hypertension
Vasodilator stress (MPI)	Adenosine, dipyridamole, regadenoson	Coronary vasodilation	Asthma, COPD	High-grade AV block, severe hypotension
Exercise stress	Treadmill/bicycle	Physiological demand	Can exercise adequately	Cannot exercise (orthopaedic, neurological)

[PMID: 24128014]

Imaging Considerations:

Stress echocardiography: Assesses wall motion abnormalities; good specificity
Myocardial perfusion imaging (MPI): Detects ischemic territories; radiation exposure
CT coronary angiography (CCTA): Anatomical assessment; useful for intermediate-risk patients
Cardiac MRI: Excellent tissue characterization; limited availability

Interpreting Stress Test Results:

Result	Management
Low-risk (no ischemia, normal LV function)	Proceed to surgery
Intermediate-risk (mild-moderate ischemia)	Optimise medical therapy; consider surgery with enhanced monitoring
High-risk (large ischemic territory, LV dysfunction)	Consider coronary angiography; may need revascularisation

Preoperative Coronary Angiography and Revascularisation

Indications for Coronary Angiography:

High-risk stress test results with large ischemic burden
Unstable angina or acute coronary syndromes
Significant left main or three-vessel disease on non-invasive testing
Clinical instability requiring definitive diagnosis

Revascularisation Timing:

Balloon angioplasty: Surgery can proceed after 2 weeks (if no stent)
Bare metal stent: Delay elective surgery 30 days minimum; 90 days optimal
Drug-eluting stent: Delay elective surgery 12 months; minimum 6 months if compelling surgical indication
CABG: Delay elective non-cardiac surgery 3-6 months

Dual Antiplatelet Therapy Considerations:

Premature discontinuation of DAPT risks stent thrombosis (mortality 40-50%)
If surgery cannot be delayed: Continue aspirin; bridge with cangrelor or glycoprotein inhibitors if appropriate
Multidisciplinary discussion essential (cardiology, surgery, anaesthesia)

[PMID: 24128014, 26951247]

Perioperative Medical Management

Beta-Blocker Therapy

Evidence Evolution:

Earlier studies suggested perioperative beta-blockade reduced cardiac events [PMID: 10522955]
POISE trial (2008) demonstrated harm with high-dose, acute beta-blocker initiation [PMID: 18480113]
Current guidelines recommend continuation of chronic beta-blockers but avoidance of acute high-dose initiation

Current Recommendations:

Scenario	Recommendation	Rationale
On chronic beta-blocker	Continue perioperatively	Avoid withdrawal (rebound hypertension, tachycardia, ischemia)
Not on beta-blocker, high-risk	Consider initiated >2 weeks preoperatively with dose titration	Risk stratification required
Acute high-dose initiation	Avoid	Increased risk of stroke, hypotension, death (POISE trial)
Day of surgery initiation	Generally avoid	No proven benefit; potential harm

[PMID: 18480113, 24128014]

Perioperative Management:

Continue beta-blockers on day of surgery with sip of water
Monitor for hypotension and bradycardia intraoperatively
Restart oral beta-blocker postoperatively as soon as feasible
If NPO status prolonged, consider IV esmolol or metoprolol

Statin Therapy

Evidence for Perioperative Statins:

Statins have pleiotropic effects (anti-inflammatory, plaque stabilisation, endothelial function)
Observational studies suggest reduced cardiac events in statin users [PMID: 18606420]
DECREASE III trial (fluvastatin) showed reduced cardiac events in vascular surgery

Recommendations:

Continue statins perioperatively in patients already taking them
Consider starting statins in high-risk patients undergoing vascular surgery
Initiate at least 2 weeks preoperatively for potential benefit
No benefit from acute perioperative statin initiation

Antiplatelet Therapy

Aspirin:

Continue aspirin in most patients with high cardiovascular risk or recent stent
May increase bleeding risk slightly but generally manageable
Discontinuation in high-risk patients may precipitate acute coronary syndrome

P2Y12 Inhibitors (Clopidogrel, Prasugrel, Ticagrelor):

Timing of discontinuation depends on stent type (see revascularisation section)
Coordinate with surgeon regarding bleeding risk vs stent thrombosis risk
Consider bridging strategies in very high-risk patients if surgery cannot be delayed

Heart Failure Management

Preoperative Optimisation:

Ensure euvolaemia; treat pulmonary congestion preoperatively
Optimise ACE inhibitor/ARB and beta-blocker therapy
Consider aldosterone antagonists if indicated
Address precipitating factors (anaemia, thyroid dysfunction, arrhythmias)

BNP/NT-proBNP:

Preoperative BNP >92 pg/mL or NT-proBNP >300 pg/mL predicts cardiac complications
Can be used to guide intensity of monitoring and follow-up
Rising values postoperatively may indicate cardiac decompensation

Indigenous Health Considerations

Aboriginal and Torres Strait Islander Health

Aboriginal and Torres Strait Islander peoples in Australia experience significant disparities in cardiovascular health that profoundly impact preoperative cardiac risk assessment and perioperative outcomes. These disparities necessitate culturally informed, equitable approaches to perioperative care.

Cardiovascular Disease Burden:

Aboriginal Australians experience cardiovascular disease at 2-3 times the rate of non-Indigenous Australians [PMID: 29024541]
Ischaemic heart disease is the leading cause of death in Aboriginal populations
Higher rates of risk factors: diabetes (3-4 times higher), hypertension, smoking, obesity
Earlier onset of cardiovascular disease (10-15 years earlier than non-Indigenous)
Higher prevalence of rheumatic heart disease in remote communities

Risk Assessment Considerations:

Standard risk calculators may underestimate risk in Aboriginal populations due to higher burden of risk factors
RCRI may not fully capture the elevated cardiac risk in Indigenous patients with diabetes and renal disease
Earlier screening and lower threshold for cardiac testing indicated
Remote location may limit access to stress testing and cardiac catheterisation

Access and Equity Issues:

Geographic isolation creates barriers to preoperative cardiac workup
Long wait times for stress testing and angiography in rural/remote areas
Need for patient transport to tertiary centres for complex assessments
Telemedicine and RFDS consultation may facilitate preoperative evaluation
Cultural safety requires engagement with Aboriginal Health Workers (AHWs) and Aboriginal Liaison Officers (ALOs)

Communication and Consent:

Family involvement in medical decision-making is culturally significant
Use of interpreters and visual aids enhances understanding of cardiac risk
Explanation of preoperative testing and optimisation in culturally appropriate terms
Addressing historical mistrust of medical systems through respectful, transparent communication

Specific Clinical Considerations:

Higher prevalence of renal dysfunction requires careful RCRI calculation
Rheumatic heart disease may require specific evaluation (valve function, arrhythmias)
Higher rates of anaemia may compound cardiac risk and require preoperative optimisation
Postoperative follow-up and monitoring may be challenging in remote settings

Māori Health Considerations

Māori populations in Aotearoa New Zealand similarly experience cardiovascular health inequities that necessitate culturally informed perioperative care.

Cardiovascular Burden:

Māori experience cardiovascular disease 1.5-2 times more frequently than non-Māori
Higher rates of diabetes, hypertension, and smoking contribute to increased risk
Earlier age of cardiovascular disease onset
Higher cardiovascular mortality rates, particularly in younger age groups

Cultural Safety in Assessment:

Whānau involvement in healthcare decision-making is essential
Communication should acknowledge Māori health models (Te Whare Tapa Whā)
Cultural advisors and Māori Health Workers should be consulted
Recognition that concepts of risk and intervention may differ from Western biomedical frameworks

Access Considerations:

Rural Māori populations face similar barriers to preoperative cardiac testing as remote Aboriginal communities
Disparities in access to cardiac catheterisation and stress testing
Need for culturally appropriate preoperative education about cardiac risk and interventions
Financial barriers may delay or prevent preoperative optimisation

Clinical Considerations:

Higher prevalence of metabolic syndrome requires comprehensive metabolic assessment
Diabetes and renal dysfunction may require modified thresholds for risk stratification
Consideration of mental health comorbidities that may impact surgical recovery
Postoperative discharge planning must consider whānau support structures

Equity-Focused Approaches:

Proactive screening for cardiovascular risk factors in Māori surgical patients
Lower threshold for stress testing and specialist referral
Enhanced preoperative optimisation to address modifiable risk factors
Culturally safe follow-up care with Māori Health Providers where available

ANZCA Exam Focus

Written Examination

High-Yield Topics:

RCRI calculation and interpretation: Know all six variables and associated risk percentages
Functional capacity assessment: MET equivalents for common activities
Stress testing indications: When to test based on surgical risk and functional capacity
Beta-blocker management: When to continue vs when not to start acutely
Antiplatelet therapy timing: Stent types and recommended delays before surgery
BNP/NT-proBNP: Threshold values for risk prediction

Common Question Formats:

Calculate RCRI for given patient scenario; determine risk category
Identify which patients require stress testing vs can proceed directly to surgery
Determine appropriate perioperative beta-blocker management
Calculate timing of surgery after coronary intervention
Interpret functional capacity and determine need for further testing

Viva Voce Scenarios

Scenario 1: Preoperative Assessment Clinic

Patient: 68-year-old man for elective open abdominal aortic aneurysm repair
History: Hypertension, type 2 diabetes (diet-controlled), former smoker (20 pack-years)
Task: Perform cardiac risk assessment and outline management plan
Key Points: RCRI calculation, functional capacity assessment, need for stress testing, optimisation strategies
Pass Criteria: Appropriate risk stratification, evidence-based testing decisions, optimisation plan

Scenario 2: Urgent Surgery with Recent Stent

Patient: 62-year-old woman with drug-eluting stent placed 4 months ago for NSTEMI
Surgery: Urgent laparotomy for small bowel obstruction
Task: Address antiplatelet management and surgical timing
Key Points: Stent thrombosis risk vs bleeding risk, DAPT management, multidisciplinary decision-making
Pass Criteria: Understanding of stent thrombosis risk, appropriate consultation with cardiology, perioperative antiplatelet strategy

Scenario 3: Beta-Blocker Management

Patient: 55-year-old man on metoprolol 50mg BD for hypertension
Surgery: Elective hemicolectomy for colon cancer
Task: Discuss perioperative beta-blocker management
Key Points: Continuation vs discontinuation, POISE trial implications, haemodynamic monitoring
Pass Criteria: Correct management (continue chronic beta-blocker), understanding of risks of acute withdrawal and acute initiation

OSCE Stations

Preoperative Assessment Station:

Duration: 10 minutes
Task: Assess patient scheduled for major surgery, calculate RCRI, determine need for cardiac testing
Marking Scheme:
- History taking (risk factors, symptoms, functional capacity) (4 marks)
- RCRI calculation and interpretation (3 marks)
- Decision regarding stress testing (2 marks)
- Perioperative management plan (2 marks)
Pass: ≥9/11 marks

Communication Station - Risk Explanation:

Duration: 8 minutes
Task: Explain cardiac risk and need for stress testing to anxious patient
Marking Scheme:
- Clear explanation of risk assessment (3 marks)
- Benefits and risks of testing explained (2 marks)
- Addresses patient concerns (2 marks)
- Shared decision-making (2 marks)
Pass: ≥7/9 marks

SAQ Practice Questions

Question 1: RCRI and Risk Stratification (15 marks)

Question: A 72-year-old man is scheduled for elective right hemicolectomy for colon cancer. His past medical history includes:

Myocardial infarction 3 years ago (managed medically, no stent)
Type 2 diabetes mellitus on insulin (basal-bolus regimen)
Hypertension
Mild chronic kidney disease (creatinine 165 μmol/L, stable)
He can walk 2 flights of stairs without chest pain or dyspnoea

a) Calculate his Revised Cardiac Risk Index (RCRI) score. List each component that applies to this patient. (5 marks)

b) What is his risk category for perioperative major adverse cardiac events (MACE)? Provide approximate percentage risk. (2 marks)

c) Would you recommend preoperative stress testing? Justify your answer. (4 marks)

d) Outline your perioperative beta-blocker management. (4 marks)

Model Answer 1

a) RCRI calculation (5 marks):

Component	Present?	Points
High-risk surgery (intraperitoneal)	Yes	1
Ischaemic heart disease (prior MI)	Yes	1
Heart failure	No	0
Cerebrovascular disease	No	0
Diabetes on insulin	Yes	1
Renal dysfunction (Cr >175 μmol/L)	No (Cr 165)	0

Total RCRI score = 3 (1 mark for correct calculation)

List of components present:

High-risk surgery (intraperitoneal) (1 mark)
Ischaemic heart disease (history of MI) (1 mark)
Diabetes mellitus on insulin therapy (1 mark)
Absence of heart failure, CVD, and severe renal dysfunction (1 mark)

b) Risk category (2 marks):

Risk category: High risk (1 mark)
Approximate 30-day MACE rate: 9-11% (accept 5-11% range; 1 mark)

c) Stress testing recommendation (4 marks):

Recommendation: Stress testing NOT routinely indicated (1 mark)

Justification:

Patient has good functional capacity (can climb 2 flights of stairs = >4 METs) (1 mark)
Current guidelines (AHA/ACC, ANZCA) recommend stress testing for elevated-risk surgery with poor functional capacity, not for those with good functional capacity (1 mark)
Proceeding directly to surgery with enhanced perioperative monitoring (telemetry) is appropriate (1 mark)
Alternative acceptable answer: Could consider stress testing given RCRI ≥3, but not mandatory with good functional capacity

d) Beta-blocker management (4 marks):

Patient is NOT currently on beta-blocker:

Do NOT start beta-blocker acutely (1 mark)
Rationale: POISE trial demonstrated harm with high-dose, acute beta-blocker initiation (increased stroke, hypotension, death) (1 mark)
If beta-blocker deemed necessary: Should be initiated >2 weeks preoperatively with dose titration to resting heart rate 60-70 bpm (1 mark)
Perioperative monitoring: Telemetry, avoid hypotension and bradycardia (1 mark)

Alternative if candidate interprets as continuation:

If patient were on chronic beta-blocker: Continue perioperatively (1 mark)
Take on morning of surgery with sip of water (1 mark)
Restart postoperatively as soon as oral intake tolerated (1 mark)
Monitor for hypotension and bradycardia (1 mark)

Question 2: Antiplatelet and Stent Management (15 marks)

Question: A 68-year-old man requires urgent open abdominal aortic aneurysm repair. He had a drug-eluting stent (DES) placed in his right coronary artery 4 months ago following an NSTEMI. He is currently on aspirin 100mg daily and ticagrelor 90mg BD.

a) What is the recommended timing between drug-eluting stent (DES) placement and elective non-cardiac surgery? (2 marks)

b) What are the risks of proceeding with urgent surgery at this time regarding his stent? (3 marks)

c) Outline your antiplatelet management strategy for the perioperative period. (6 marks)

d) What discussions and consultations should occur in this scenario? (4 marks)

Model Answer 2

a) Timing after DES placement (2 marks):

Elective surgery should be delayed 12 months after DES placement (1 mark)
Minimum acceptable delay if compelling indication: 6 months (1 mark)

b) Risks of urgent surgery (3 marks):

Stent thrombosis risk: Premature discontinuation of dual antiplatelet therapy (DAPT) significantly increases risk of stent thrombosis (1 mark)
Consequences of stent thrombosis: Acute coronary syndrome, myocardial infarction, high mortality (30-50% if left main or proximal LAD) (1 mark)
Bleeding risk: Continuing antiplatelet therapy increases surgical bleeding risk, particularly with aortic surgery (1 mark)

c) Antiplatelet management strategy (6 marks):

Preoperative:

Aspirin: Continue aspirin throughout perioperative period (1 mark)
Ticagrelor: Stop 3-5 days before surgery to allow platelet function recovery (1 mark)
Rationale: Aspirin provides some protection against stent thrombosis while reducing bleeding risk compared to DAPT (1 mark)

Intraoperative:

Anticipate increased bleeding; ensure adequate IV access and blood products available (1 mark)
Consider antifibrinolytic agents (tranexamic acid) if appropriate for surgery type (1 mark)

Postoperative:

Restart ticagrelor as soon as haemostasis is secure (ideally within 24-48 hours) (1 mark)
Continue aspirin indefinitely (1 mark)

Alternative strategies (acceptable if discussed with cardiology):

Bridging with cangrelor or glycoprotein IIb/IIIa inhibitors (if very high-risk stent)
Platelet function testing to guide timing of surgery

d) Discussions and consultations (4 marks):

Urgent cardiology consultation: Discuss risk of stent thrombosis vs surgical urgency; consider whether surgery can be delayed further (1 mark)
Vascular surgery discussion: Assess whether endovascular repair (lower bleeding risk) is anatomically feasible (1 mark)
Anaesthesia consultation: Plan for haemodynamic monitoring, blood product availability, potential need for intraoperative/postoperative ICU care (1 mark)
Informed consent: Discuss risks of stent thrombosis and bleeding with patient/family; document discussion and decision-making (1 mark)

Question 3: Functional Capacity and Stress Testing (15 marks)

Question: A 55-year-old woman is scheduled for elective total hip replacement. She has a history of well-controlled hypertension and hyperlipidaemia. She reports that she walks her dog for 30 minutes daily on flat ground without symptoms. She has never had chest pain, dyspnoea, or orthopnoea.

a) Estimate her functional capacity in METs based on her reported activity. (2 marks)

b) What is her Revised Cardiac Risk Index (RCRI) score? (3 marks)

c) Would you recommend preoperative cardiac stress testing? Provide justification. (5 marks)

d) Outline three non-cardiac risk factors that should be assessed in your preoperative evaluation for this patient. (3 marks)

e) What are the contraindications to pharmacological stress testing with adenosine or dipyridamole? (2 marks)

Model Answer 3

a) Functional capacity estimation (2 marks):

Walking 30 minutes on flat ground ≈ 2-3 METs (1 mark)
This represents poor functional capacity (<4 METs) (1 mark)

b) RCRI score calculation (3 marks):

Component	Present?	Points
High-risk surgery	No (orthopaedic is intermediate risk)	0
Ischaemic heart disease	No	0
Heart failure	No	0
Cerebrovascular disease	No	0
Diabetes on insulin	No	0
Renal dysfunction	No	0

Total RCRI score = 0 (1 mark for calculation, 2 marks for identifying zero risk factors)

c) Stress testing recommendation (5 marks):

Recommendation: NO routine stress testing required (1 mark)