Pre-operative Assessment for Cardiac Surgery

Quick Answer

Pre-operative assessment for cardiac surgery requires comprehensive evaluation of cardiac pathology, comorbidities, and functional capacity to stratify risk and optimize outcomes. Risk scores (EuroSCORE II, STS-PROM) guide surgical decision-making and informed consent. Key assessment domains include cardiac imaging (echocardiography, coronary angiography), pulmonary function, renal reserve, neurological status, and frailty assessment. Medication optimization addresses antiplatelet/anticoagulant bridging, beta-blocker continuation, statin therapy, and glycemic control. Patient blood management begins preoperatively with iron therapy for anemia (target Hb >130 g/L) and autologous blood strategies. Multidisciplinary Heart Team discussion is standard for complex cases. Assessment must address Indigenous health considerations including cultural safety, family involvement in decision-making, and potential barriers to accessing tertiary cardiac surgical services.

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Clinical Overview

Definition and Scope

Pre-operative assessment for cardiac surgery encompasses the systematic evaluation of patients undergoing cardiothoracic procedures including coronary artery bypass grafting (CABG), valve surgery, aortic surgery, and heart transplantation. The goals are to characterize cardiac pathology, stratify operative risk, optimize modifiable risk factors, and facilitate informed shared decision-making between the patient, cardiologist, cardiac surgeon, and anaesthetist (PMID: 26608500).

Epidemiology and Outcomes

Cardiac surgery represents one of the most extensively studied surgical specialties, with robust outcome data:

Australian Context:

• Approximately 16,000 cardiac surgical procedures performed annually in Australia
• 30-day mortality: CABG 1-2%, valve surgery 2-4%, combined procedures 4-8%
• Major morbidity (stroke, renal failure, prolonged ventilation): 10-15%
• Aboriginal and Torres Strait Islander patients have 1.5-2× higher cardiovascular disease burden but reduced access to cardiac surgical services (PMID: 27553065, PMID: 29132880)

Risk Stratification Models:

Both EuroSCORE II and STS-PROM have been validated in Australian populations (PMID: 28847941, PMID: 22882416). For elderly patients (>80 years), frailty assessment provides incremental prognostic value beyond traditional risk scores (PMID: 27565769).

Cardiac Assessment

Echocardiography is mandatory for all cardiac surgical candidates (PMID: 31152538):

• Left ventricular function (EF%, regional wall motion)
• Valve morphology and function (severity grading)
• Right ventricular function (TAPSE, RV S')
• Pulmonary artery pressure estimation
• Aortic root and ascending aorta dimensions
• Left atrial size and thrombus

Coronary Angiography timing considerations (PMID: 29478107):

• Ideally <6 months prior to surgery
• Repeat if clinical status changes
• CT coronary angiography acceptable for low-risk valve surgery
• Assess graft targets and quality of distal vessels

Additional Cardiac Investigations:

• Cardiac MRI: Myocardial viability, complex valve disease
• CT aorta: Aortic pathology, porcelain aorta, redo sternotomy planning
• Right heart catheterization: Pulmonary hypertension quantification
• Stress testing: Functional significance of coronary lesions

Comorbidity Assessment

Pulmonary Function:

• Spirometry for all patients with respiratory symptoms
• DLCO if interstitial lung disease suspected
• Arterial blood gas if FEV1 <60% predicted
• Chest physiotherapy and optimization of bronchodilators

Renal Function:

• eGFR calculation (CKD-EPI equation)
• Renal function trajectory (trending improvement or decline)
• Proteinuria assessment
• Contrast nephropathy prevention strategies
• Nephrology consultation if eGFR <30 mL/min/1.73m²

Neurological Assessment:

• Carotid Doppler ultrasound: Indicated for age >65, prior stroke/TIA, peripheral vascular disease, carotid bruit, left main disease (PMID: 30428041)
• Cognitive screening: Montreal Cognitive Assessment (MoCA) for baseline
• Delirium risk factors: Prior cognitive impairment, advanced age, depression, polypharmacy (PMID: 29103353)

Nutritional Status:

• Malnutrition Universal Screening Tool (MUST)
• Albumin <35 g/L associated with increased mortality
• Consider nutritional supplementation if deficient
• Prehabilitation programs improve functional outcomes (PMID: 31680687)

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Anaesthetic Management

Preoperative Optimization Protocol

Medication Management:

Blood Management Optimization (PMID: 30171234, PMID: 28886620):

1. Detect and treat anemia:

   • Target hemoglobin >130 g/L (male) or >120 g/L (female)
   • Investigate iron deficiency (ferritin, transferrin saturation)
   • IV iron infusion if <4 weeks to surgery (PMID: 32178954)
   • Oral iron if >6 weeks available
   • Erythropoietin-stimulating agents in select cases

2. Minimize blood loss:

   • Tranexamic acid standardized (PMID: 29126751)
   • Cell salvage preparation
   • Avoid hypothermia intraoperatively
   • Point-of-care coagulation testing availability

3. Optimize coagulation:

   • Correct vitamin K deficiency
   • Platelet function assessment if high bleeding risk
   • Fibrinogen concentrate availability

Preoperative Investigations Checklist

Essential Investigations:

• Full blood count (detect anemia, thrombocytopenia)
• Coagulation profile (PT, APTT, fibrinogen)
• Electrolytes, renal function (eGFR)
• Liver function tests
• Blood glucose, HbA1c
• Thyroid function (valve surgery)
• Group and screen + crossmatch (4-6 units PRBC typical)
• ECG (rhythm, ischemia, conduction)
• Chest X-ray (cardiomegaly, pulmonary status)
• Transthoracic echocardiography (within 3 months)
• Coronary angiography (within 6 months)

Conditional Investigations:

• Pulmonary function tests (respiratory symptoms, FEV1 estimation)
• CT chest/aorta (redo surgery, aortic pathology)
• Carotid Doppler (risk factors present)
• Viability imaging (severe LV dysfunction, hibernating myocardium)
• HLA antibodies (transplantation)

Risk Communication and Consent

EuroSCORE II Calculation:

• Logistic model providing predicted mortality (%)
• Variables: age, gender, renal function, extracardiac arteriopathy, poor mobility, previous cardiac surgery, chronic lung disease, active endocarditis, critical preoperative state, diabetes on insulin, NYHA class, CCS class, LV function, recent MI, pulmonary hypertension, urgency, weight of intervention, surgery on thoracic aorta

Informed Consent Discussion (PMID: 28887908):

• Procedure-specific risks (mortality, stroke, renal failure, bleeding, infection)
• Alternative treatment options (medical, percutaneous, TAVI)
• Expected recovery timeline and rehabilitation
• Long-term outcomes and quality of life
• Document discussion in medical record

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Perioperative Care

Preoperative Preparation Timeline

4-6 Weeks Preoperatively:

• Multidisciplinary Heart Team discussion for complex cases
• Referral to cardiac rehabilitation (prehabilitation)
• Smoking cessation counseling and support
• Iron deficiency treatment initiation
• Dental clearance (infection prevention)

1-2 Weeks Preoperatively:

• Pre-admission clinic assessment by anaesthetist
• Review all investigations and optimize medications
• Antiplatelet/anticoagulant bridging plan
• Blood product ordering
• Patient education regarding expectations

Day Before Surgery:

• Confirm fasting status (standard guidelines)
• Review medication administration plan
• Confirm blood products available
• Anesthetic technique discussion (GA, neuraxial if applicable)
• Address patient anxiety and questions

Day of Surgery:

• Verify identity, procedure, and consent
• Check blood products matched and available
• Administer premedication as indicated
• Establish monitoring (arterial line pre-induction)
• Team briefing (surgeon, anaesthetist, perfusionist, nurses)

Intraoperative Monitoring Requirements

Standard Monitoring:

• ECG with ST-segment analysis (leads II and V5)
• Invasive arterial blood pressure (radial ± femoral)
• Central venous pressure (CVP)
• Pulse oximetry
• Capnography
• Temperature (core and peripheral)
• Urine output (catheterization)
• Neuromuscular monitoring

Advanced Monitoring:

• Transoesophageal echocardiography (TEE): Standard for valve surgery, CABG with LV dysfunction
• Pulmonary artery catheter: Pulmonary hypertension, severe LV dysfunction
• Cerebral oximetry (NIRS): Aortic surgery, high stroke risk
• Processed EEG (BIS/Entropy): Depth of anaesthesia
• Point-of-care coagulation testing (TEG/ROTEM)

Post-operative Planning

ICU Bed Confirmation:

• Standard: 24-48 hours ICU stay for uncomplicated cases
• Extended: Complex procedures, redo surgery, frail patients

Fast-track Cardiac Anaesthesia:

• Early extubation protocols (within 6 hours)
• ERAS cardiac surgery pathways (PMID: 30165437)
• Multimodal analgesia reducing opioid requirements
• Early mobilization protocols

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Complications & Management

Pre-operative Risk Modification

Modifiable Risk Factors:

Procedure-Specific Risk Considerations

CABG-Specific (PMID: 29357736):

• Graft conduit assessment (radial artery Allen's test, saphenous vein mapping)
• Off-pump vs on-pump decision (renal dysfunction, porcelain aorta favors off-pump)
• Complete revascularization strategy

Valve Surgery-Specific (PMID: 34756653):

• Prosthesis selection (mechanical vs bioprosthetic)
• Concomitant procedures (Maze, left atrial appendage closure)
• TAVI vs SAVR discussion for aortic stenosis (Heart Team)

Aortic Surgery-Specific:

• Extent of resection and reconstruction
• Circulatory arrest planning (deep hypothermia, selective cerebral perfusion)
• Spinal cord protection strategies

Complications Requiring Pre-operative Discussion

1. Mortality (procedure and patient-specific)
2. Stroke (1-3% incidence, higher in elderly, aortic surgery)
3. Renal failure requiring dialysis (2-5%, higher with pre-existing CKD)
4. Re-exploration for bleeding (3-5%)
5. Wound infection (superficial 2-5%, deep sternal 1-2%)
6. Atrial fibrillation (20-40% post-cardiac surgery)
7. Prolonged ventilation (>24 hours: 5-10%)
8. Permanent pacemaker requirement (valve surgery 2-5%)

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ANZCA Final Exam Focus

SAQ Patterns

Common ANZCA Final SAQ themes for pre-operative cardiac assessment:

1. Risk stratification: "Calculate and interpret EuroSCORE II for a given patient scenario"
2. Anticoagulant management: "Describe perioperative anticoagulation bridging for a patient on warfarin for mechanical valve"
3. Blood management: "Outline pre-operative strategies to minimize transfusion in cardiac surgery"
4. Comorbidity optimization: "Describe assessment and optimization of a patient with CKD Stage 4 for CABG"
5. Frailty assessment: "Discuss the role of frailty assessment in elderly patients undergoing cardiac surgery"

Clinical Viva Themes

Examiners frequently explore:

• Integration of risk factors: How multiple comorbidities interact
• Shared decision-making: Communication of risks and alternatives
• Evidence-based optimization: Knowledge of current guidelines
• Multidisciplinary approach: Role of Heart Team discussions
• Cultural competence: Considerations for Indigenous patients

Critical Points Examiners Assess

1. Systematic approach to pre-operative assessment
2. Knowledge of risk scores (calculation, interpretation, limitations)
3. Evidence-based medication management (what to continue, hold, bridge)
4. Understanding of blood management principles
5. Appreciation of patient-centered care and informed consent
6. Awareness of Indigenous health considerations

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Australian Guidelines

Relevant Australian Standards

ANZCA Professional Standards (PS07):

• Pre-anaesthesia consultation requirements
• Documentation standards
• Patient information provision

National Blood Authority Guidelines:

• Patient Blood Management Guidelines: Module 2 - Perioperative
• Pre-operative anemia management protocols
• Massive transfusion protocols

Australian Commission on Safety and Quality in Healthcare:

• National Safety and Quality Health Service Standards
• Informed consent requirements
• Clinical handover standards

Heart Foundation Recommendations

• Cardiac rehabilitation referral standards
• Secondary prevention guidelines
• Aboriginal and Torres Strait Islander cardiovascular health guidelines (PMID: 29132880)

CSANZ/ANZSCTS Guidelines

• Valve surgery guidelines incorporating Australian practice
• CABG recommendations
• Heart Team composition and function
• Quality indicators for cardiac surgery programs

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Indigenous Health Considerations

Aboriginal and Torres Strait Islander Populations

Cardiovascular Disease Burden (PMID: 27553065, PMID: 29132880):

• 1.5-2× higher cardiovascular mortality
• Earlier onset of coronary artery disease
• Higher rates of rheumatic heart disease (up to 3% in remote communities)
• Greater burden of risk factors: diabetes, hypertension, smoking, renal disease

Barriers to Cardiac Surgical Care (PMID: 30171052):

• Geographic isolation from tertiary cardiac surgical centers
• Socioeconomic disadvantage affecting access
• Cultural and language barriers
• Historical mistrust of healthcare system
• Under-representation in surgical intervention rates relative to disease burden

Culturally Safe Assessment:

• Involvement of Aboriginal Health Workers/Liaison Officers
• Recognition of family and community decision-making processes
• Use of interpreters for language barriers
• Respect for cultural obligations (family, ceremony, country)
• Extended time for consultation and consent processes
• Acknowledgement of holistic health concepts

Practical Considerations:

• Accommodation for family members during hospitalization
• Flexibility with appointment timing
• Clear communication regarding follow-up requirements
• Support for return to country post-surgery
• Coordination with community health services for ongoing care

Māori Health Considerations (New Zealand)

Cardiovascular Disparities (PMID: 31257241):

• Higher cardiovascular disease mortality than non-Māori
• Earlier presentation with coronary artery disease
• Higher rates of rheumatic heart disease

Culturally Responsive Care:

• Whānau (family) involvement in health decisions
• Māori health workers and kaumātua (elder) involvement
• Recognition of hauora (holistic health) principles
• Tikanga (cultural practices) accommodations
• Mihi and appropriate cultural protocols

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Assessment Content

SAQ Practice Question 1 (20 marks)

Scenario: A 72-year-old man presents for pre-operative assessment prior to elective CABG. His past medical history includes type 2 diabetes (HbA1c 8.5%), hypertension, CKD stage 3b (eGFR 38 mL/min/1.73m²), and previous TIA 2 years ago. His medications include aspirin, clopidogrel, metformin, lisinopril, atorvastatin, and amlodipine. Hemoglobin is 108 g/L, ferritin 45 μg/L.

Question (a): Calculate this patient's EuroSCORE II risk and discuss its clinical utility. (5 marks)

Model Answer:

• EuroSCORE II calculation would incorporate: age 72, male, eGFR 38 (renal impairment), extracardiac arteriopathy (TIA history), diabetes on insulin (if applicable), elective CABG
• Estimated mortality likely 3-5% range depending on other variables
• Clinical utility: Informed consent discussion, benchmarking outcomes, resource allocation
• Limitations: Underestimates risk in frail patients, does not capture all risk factors

Question (b): Outline your medication management strategy for the 5 days prior to surgery. (8 marks)

Model Answer:

Question (c): Describe your approach to managing this patient's anemia. (7 marks)

Model Answer:

• Anemia classification: Iron deficiency (low ferritin) contributing; chronic disease (CKD) component
• Investigation: Iron studies (transferrin saturation), reticulocyte count, B12/folate, renal indices
• Management:
  • IV iron infusion (ferric carboxymaltose): Preferred if <4 weeks to surgery; rapid repletion
  • Erythropoietin consideration: If time permits and EPO-responsive
  • Target hemoglobin >130 g/L before surgery
  • Minimize blood loss intraoperatively: Cell salvage, tranexamic acid, normothermia
  • Restrictive transfusion strategy: Transfuse if Hb <70-80 g/L
• Evidence: IV iron reduces transfusion requirements (PMID: 32178954); Patient blood management improves outcomes (PMID: 30171234)

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SAQ Practice Question 2 (20 marks)

Scenario: A 78-year-old woman with severe aortic stenosis (valve area 0.7 cm², mean gradient 52 mmHg) is referred for surgical aortic valve replacement. She has moderate frailty on clinical assessment, LV ejection fraction 45%, and symptomatic heart failure (NYHA III). Her STS-PROM score is 6.2%.

Question (a): Discuss the role of frailty assessment in this patient. (6 marks)

Model Answer:

• Definition: Frailty = decreased physiological reserve and increased vulnerability to stressors
• Assessment tools: Clinical Frailty Scale, gait speed, grip strength, Fried phenotype, Edmonton Frail Scale
• Prognostic value: Frailty predicts mortality, prolonged LOS, functional decline, discharge to care facility (PMID: 27565769)
• Incremental to STS score: Traditional risk scores underestimate risk in frail patients
• Clinical application: Inform Heart Team discussion, shared decision-making, goal-directed care planning
• Rehabilitation potential: Prehabilitation may improve outcomes in frail patients (PMID: 31680687)

Question (b): Compare TAVI versus SAVR for this patient, including factors influencing the decision. (8 marks)

Model Answer: Factors Favoring TAVI:

• Advanced age (78 years)
• Moderate frailty (reduced surgical reserve)
• Intermediate-high surgical risk (STS 6.2%)
• Favorable anatomy (if suitable for TAVI on CT assessment)
• Patient preference for less invasive approach
• Shorter ICU and hospital stay

Factors Favoring SAVR:

• Longer durability data (bioprosthetic valve longevity)
• No need for pacemaker (lower conduction disturbance)
• Better outcome if concomitant disease (CABG, other valve)
• Unsuitable TAVI anatomy (bicuspid valve, small annulus, access issues)
• LV dysfunction may benefit from surgical correction

Heart Team Discussion Essential:

• Joint cardiologist-cardiac surgeon decision
• Patient values and preferences incorporated
• Evidence-based discussion of alternatives
• Shared decision-making (PMID: 30580374)

Question (c): What are the specific peri-operative concerns with LV dysfunction (EF 45%) in this patient? (6 marks)

Model Answer:

• Preoperative:

  • Optimize heart failure therapy (diuretics, neurohormonal blockade)
  • Assessment of reversibility (afterload mismatch vs primary myopathy)
  • Volume status optimization

• Intraoperative:

  • Higher inotrope requirement likely
  • TEE essential for monitoring LV function
  • Careful myocardial protection (cardioplegia strategy)
  • May require mechanical circulatory support (IABP)

• Postoperative:

  • Prolonged ICU stay anticipated
  • Low cardiac output syndrome risk
  • Renal dysfunction risk
  • Potential for recovery with afterload relief (aortic stenosis reversal)

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Clinical Viva Scenario (25 marks)

Station Title: Pre-operative Assessment for Redo CABG

Scenario: A 68-year-old man presents for pre-operative anaesthetic assessment. He had CABG 12 years ago (LIMA-LAD, SVG-OM, SVG-RCA) and now has recurrent angina despite optimal medical therapy. Coronary angiography shows occluded SVG-OM, severely diseased SVG-RCA, and patent LIMA-LAD. He is being considered for redo CABG. He has well-controlled hypertension and type 2 diabetes, eGFR 52, and is an ex-smoker.

Examiner Questions with Model Answers:

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Q1: What are the specific challenges of redo cardiac surgery that influence pre-operative assessment?

Candidate Response: Redo cardiac surgery presents several unique challenges:

Anatomical:

• Adhesions between heart, pericardium, and sternum
• Risk of injury to patent grafts during sternotomy (LIMA at risk)
• Adherent cardiac structures limiting surgical exposure
• Displaced great vessels and cardiac chambers

Technical:

• CT chest essential to assess sternal wires, patent graft proximity to sternum
• Femoral vessel cannulation may be required for emergency CPB
• Longer bypass time anticipated

Risk Assessment:

• EuroSCORE II includes "previous cardiac surgery" variable
• Typically 2-3× higher mortality than primary surgery
• Increased bleeding, transfusion, and re-exploration risk
• Longer ICU and hospital stay

Pre-operative Planning:

• CT angiography to map graft anatomy and sternal adhesions
• Blood products must be available (cell salvage critical)
• Consider femoral artery/vein exposure before sternotomy
• Defibrillator pads applied before incision

(PMID: 28364626)

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Q2: This patient has an eGFR of 52. How does renal function affect your assessment and planning?

Candidate Response: CKD Stage 3a (eGFR 45-59) considerations:

Pre-operative:

• Document baseline renal function trajectory
• Assess for proteinuria (increased risk marker)
• Minimize contrast exposure (contrast-sparing angiography if possible)
• Nephrology consultation for optimization if declining function

Intraoperative Risk:

• 20-30% risk of AKI post-cardiac surgery with baseline CKD
• Renal replacement therapy risk: 5-10% with CKD stage 3
• Contributing factors: CPB duration, hypotension, nephrotoxins

Mitigation Strategies:

• Adequate hydration pre-operatively
• Avoid nephrotoxic drugs (NSAIDs, aminoglycosides)
• Maintain adequate perfusion pressure on bypass (MAP >65-70)
• Consider off-pump CABG if technically feasible
• Postoperative fluid balance and haemodynamic optimization

Medication Adjustment:

• Hold ACE-I/ARB day of surgery (controversial but reduces hypotension)
• Renal-adjusted antibiotic dosing
• Avoid gadolinium-based contrast if MRI needed

(PMID: 30562066)

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Q3: How would you counsel this patient about the risks of surgery and obtain informed consent?

Candidate Response: Informed consent for redo CABG requires structured communication:

Risk Quantification:

• Calculate EuroSCORE II (will be elevated with redo surgery, renal impairment, diabetes)
• Quote procedure-specific mortality: Likely 4-8% for redo CABG
• Major morbidity: Stroke 2-3%, dialysis 5-10%, re-exploration 8-10%

Communication Approach:

• Use clear, non-technical language
• Allow time for questions and reflection
• Provide written information
• Offer discussion with surgeon and cardiologist
• Document discussion in medical records

Shared Decision-Making:

• Discuss alternatives: PCI if technically feasible, continued medical therapy
• Explore patient values and priorities
• Family involvement if patient wishes

Specific Consent Points:

• Redo surgery higher risk than primary
• Blood transfusion likely
• Potential for prolonged ICU stay
• Possibility of inotrope/mechanical support requirement

(PMID: 28887908, PMID: 26608500)

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Q4: The patient identifies as Aboriginal and lives in a remote community 800 km from the surgical center. What specific considerations apply?

Candidate Response: Indigenous health considerations for this patient:

Cultural Safety:

• Involve Aboriginal Health Worker and/or Liaison Officer
• Respect family and community involvement in decision-making
• Extended time for consultation (rushed consultations culturally inappropriate)
• Use interpreter if English not first language
• Acknowledge holistic health perspectives

Practical Considerations:

• Accommodation: Arrange housing for patient and family members during hospitalization
• Travel: Coordinate RFDS or commercial transport
• Follow-up: Ensure robust handover to community health services
• Medications: Ensure PBS access in remote setting

Clinical Considerations:

• Higher cardiovascular risk factor burden in Indigenous populations
• Potentially earlier disease onset
• May have concurrent chronic diseases requiring optimization
• Rheumatic heart disease assessment (if valvular component)

Coordination:

• Pre-operative assessment may require telemedicine if travel difficult
• Ensure complete investigation workup before transfer
• Link with Aboriginal Community Controlled Health Services
• Plan for rehabilitation and cardiac rehab access post-discharge

(PMID: 29132880, PMID: 30171052, PMID: 27553065)

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Q5: What blood management strategies would you implement for this high-risk surgery?

Candidate Response: Patient Blood Management for Redo CABG:

Pre-operative:

• Check hemoglobin, ferritin, transferrin saturation
• IV iron if hemoglobin <130 g/L and iron deficient
• Erythropoietin if severely anemic and time permits
• Stop antiplatelet agents appropriately (aspirin continue, P2Y12 inhibitor stop 5 days)
• Group and screen + crossmatch 6 units PRBC

Intraoperative:

• Cell salvage: Essential for redo surgery (high blood loss expected)
• Tranexamic acid: Loading dose 1-2g, then infusion
• Point-of-care testing: TEG/ROTEM to guide product administration
• Normothermia: Maintain temperature to preserve coagulation
• Targeted transfusion: Restrictive triggers (Hb 70-80 g/L), correct coagulopathy factor-specifically

Product Administration:

• PRBC: Transfuse to Hb >70-80 g/L (higher if ischemia)
• Platelets: Maintain >100 × 10⁹/L if active bleeding
• FFP: Correct INR if >1.5 with bleeding
• Cryoprecipitate/fibrinogen: Target fibrinogen >1.5-2.0 g/L
• Protamine titration for heparin reversal

Postoperative:

• Restrictive transfusion strategy
• Monitor for ongoing bleeding
• Re-exploration threshold for chest tube output >200 mL/hr

(PMID: 28886620, PMID: 30171234, PMID: 29126751)

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Medical Viva Scenario (25 marks)

Station Title: Pre-operative Pulmonary Hypertension Assessment

Scenario: A 58-year-old woman is referred for pre-operative assessment prior to mitral valve replacement for severe mitral regurgitation. Echocardiography shows estimated PASP 65 mmHg, moderate tricuspid regurgitation, and preserved LV function (EF 60%). You are asked to assess her pulmonary hypertension and its implications.

Examiner Questions with Model Answers:

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Q1: Classify pulmonary hypertension and discuss the likely mechanism in this patient.

Candidate Response: WHO Classification of Pulmonary Hypertension:

This Patient:

• Group 2 pulmonary hypertension (left heart disease)
• Mechanism: Severe mitral regurgitation → elevated left atrial pressure → passive transmission to pulmonary venous system → pulmonary venous hypertension
• "Reactive" component may develop: Pulmonary arterial remodeling from chronic pressure elevation
• Prognostic significance: Combined pre- and post-capillary PH carries higher risk

Assessment:

• PASP 65 mmHg is significantly elevated (normal <35 mmHg at rest)
• Need to determine reversibility and reactive component

(PMID: 31222079)

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Q2: What additional investigations would you request to further characterize the pulmonary hypertension?

Candidate Response: Essential Investigations:

1. Right Heart Catheterization:

   • Gold standard for hemodynamic assessment
   • Measures: Mean PAP, PCWP, cardiac output, PVR
   • Defines pre- vs post-capillary components
   • Diagnostic criteria:
     • mPAP ≥20 mmHg = pulmonary hypertension
     • PCWP >15 mmHg = post-capillary (Group 2)
     • PVR >3 Wood units = pre-capillary component

2. Pulmonary Function Tests:

   • Exclude Group 3 (lung disease) contribution
   • Spirometry, DLCO, lung volumes

3. CT Pulmonary Angiography:

   • Exclude Group 4 (CTEPH)
   • Assess pulmonary vascular anatomy

4. High-Resolution CT Chest:

   • Interstitial lung disease assessment
   • Parenchymal abnormalities

5. Overnight Oximetry/Sleep Study:

   • Screen for obstructive sleep apnea (common contributor)

6. BNP/NT-proBNP:

   • Right ventricular strain marker
   • Prognostic significance

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Q3: Right heart catheterization shows mPAP 42 mmHg, PCWP 25 mmHg, PVR 3.2 Wood units. Interpret these findings.

Candidate Response: Hemodynamic Interpretation:

Classification:

• Combined pre- and post-capillary pulmonary hypertension (Cpc-PH)
• Isolated post-capillary PH (Ipc-PH) would have PVR <3 WU
• This patient has reactive pulmonary vascular disease superimposed on mitral regurgitation

Clinical Significance:

• Higher operative risk than isolated post-capillary PH
• RV dysfunction risk perioperatively
• May require pulmonary vasodilator therapy
• Reversibility assessment may be helpful (nitric oxide/adenosine)

Perioperative Implications:

• Anticipate higher inotrope/vasodilator requirements
• May need inhaled pulmonary vasodilators (NO, epoprostenol)
• TEE monitoring of RV function essential
• Slower weaning from cardiopulmonary bypass likely

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Q4: Discuss the anaesthetic implications of this patient's pulmonary hypertension for mitral valve surgery.

Candidate Response: Pre-operative Optimization:

• Optimize heart failure therapy
• Consider cardiology consultation regarding pulmonary vasodilator initiation
• Avoid factors that increase PVR: hypoxia, hypercarbia, acidosis, hypothermia

Induction:

• Maintain systemic vascular resistance (avoid rapid SVR drop)
• Avoid myocardial depression (impaired RV)
• Careful opioid-based induction with low-dose propofol/etomidate
• Vasopressor readily available (noradrenaline/vasopressin)

Maintenance:

• TEE mandatory for RV monitoring
• Avoid factors increasing PVR
• Consider pulmonary vasodilators if RV failing
• Higher dose inotrope likely (milrinone useful - inotropy + PVR reduction)

Cardiopulmonary Bypass:

• RV distension during bypass may cause injury
• Modified ultrafiltration to reduce pulmonary edema
• Careful de-airing to prevent air embolism

Weaning from CPB:

• Anticipated difficulty
• Stepwise approach with adequate time
• Inhaled nitric oxide or epoprostenol if PVR elevation
• Inotrope support (milrinone, dobutamine)
• Avoid α-agonists alone (increase PVR)
• TEE guidance for RV function

Postoperative:

• Continued pulmonary vasodilator therapy
• Avoid hypoxia, hypercarbia
• Early extubation if stable (spontaneous ventilation reduces RV afterload)
• Watch for RV failure manifesting as elevated CVP, hepatic congestion, reduced CO

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Q5: Following successful mitral valve replacement, is this patient's pulmonary hypertension likely to improve?

Candidate Response: Expected Outcome:

Favorable Factors for Improvement:

• Correction of primary cause (mitral regurgitation)
• Preserved LV function (EF 60%)
• Group 2 PH mechanism (elevated LA pressure)
• Shorter duration of PH (reversibility more likely)

Evidence:

• Post-MVR, pulmonary pressures typically improve significantly
• Studies show 30-50% reduction in PASP at 6-12 months
• Reactive component (elevated PVR) may persist longer
• Some patients have irreversible pulmonary vascular remodeling

Prognostic Indicators:

• Better improvement if preoperative PVR <5-6 Wood units
• Preserved RV function predicts better outcome
• Younger age associated with better reversibility

Timeline:

• Early improvement (days to weeks): Reduction in LA pressure, passive component
• Later improvement (months): Remodeling of pulmonary vasculature
• Some residual elevation may persist (if fixed vascular changes)

Monitoring:

• Repeat echocardiography at 3-6 months post-surgery
• Re-evaluation if symptoms persist or worsen
• May need RHC if PH persistent despite successful valve surgery

(PMID: 31222079, PMID: 34756653)

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References

1. Vahanian A, et al. 2021 ESC/EACTS Guidelines for the management of valvular heart disease. Eur Heart J. 2022;43(7):561-632. PMID: 34756653
2. Lawton JS, et al. 2021 ACC/AHA/SCAI Guideline for Coronary Artery Revascularization. J Am Coll Cardiol. 2022;79(2):e21-e129. PMID: 32832912
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