# Clinical Cases: Cardiothoracic Surgery

## Case 1: Aortic Valve Stenosis Requiring TAVR vs SAVR

### Patient Presentation
**Demographics:** 78-year-old male retired professor of history

**Chief Complaint:** "I nearly fainted while climbing the stairs to my study last week, and I've been getting more winded over the past few months."

**History of Present Illness:**
Dr. H.M. presents to the cardiothoracic surgery clinic after referral from cardiology for evaluation of severe symptomatic aortic stenosis. He reports a 6-month history of progressive exertional dyspnea, initially noticed while walking uphill or climbing two flights of stairs (previously could walk 3 miles without limitation). Three weeks ago, he experienced a near-syncopal episode while ascending stairs — he felt lightheaded, had graying of vision, and needed to sit down for several minutes. He did not lose consciousness. He also reports exertional chest pressure described as a "heaviness" across his anterior chest during brisk walking, relieved by rest.

His cardiologist performed an echocardiogram that revealed severe aortic stenosis with a trileaflet aortic valve (senile/degenerative calcific AS). He was referred for evaluation for aortic valve replacement. He lives independently, drives, does his own shopping and cooking, and remains intellectually active (writing a book). His primary concern is recovery time and return to his normal activities.

**Past Medical History:**
- Hypertension (20 years, well-controlled)
- Type 2 diabetes mellitus (12 years, oral agents only)
- Chronic kidney disease stage 3a (eGFR 52 mL/min/1.73m²)
- Atrial fibrillation (paroxysmal, rate-controlled)
- Prior transient ischemic attack (TIA) 3 years ago (no residual deficits)
- Osteoarthritis bilateral knees
- Former smoker (15 pack-years, quit 30 years ago)

**Medications:**
- Amlodipine 5 mg daily
- Metformin 500 mg BID
- Apixaban 5 mg BID
- Metoprolol succinate 50 mg daily
- Atorvastatin 40 mg daily
- Aspirin 81 mg daily

**Social History:**
- Non-smoker (quit 30 years ago)
- Rare alcohol (1 glass wine per week)
- Widowed, lives alone in two-story home
- Two adult children locally, supportive
- Retired professor; writing historical biography
- Independent in all ADLs and IADLs; drives regularly

**Family History:**
- Father: died of aortic aneurysm rupture age 72
- Mother: died of congestive heart failure age 85
- Brother: aortic valve replacement (mechanical) age 68

### Physical Examination
- **Vital Signs:** BP 138/62 mmHg (wide pulse pressure paradoxically preserved due to concurrent AR), HR 72 bpm (irregular), RR 16, SpO2 96% on room air, Temp 36.7°C, BMI 24.6 kg/m²
- **General:** Well-appearing elderly gentleman, no acute distress at rest; thin habitus
- **Cardiovascular:**
  - Carotid pulses: delayed upstroke bilaterally (pulsus parvus et tardus); carotid bruits absent
  - PMI: sustained, laterally displaced to 6th intercostal space, anterior axillary line
  - Auscultation: harsh, late-peaking, grade IV/VI crescendo-decrescendo systolic ejection murmur, loudest at right upper sternal border (aortic area), radiating to bilateral carotids and cardiac apex; S2 absent (calcified immobile valve); S4 gallop present; no S3
  - Additionally: grade II/VI early diastolic blowing murmur at left sternal border (concurrent mild AR)
- **Pulmonary:** Fine bibasilar crackles (mild pulmonary congestion); no wheeze
- **Extremities:** Trace bilateral pedal edema; no clubbing; peripheral pulses palpable but diminished
- **Neurological:** Alert, oriented, cognitively intact (MMSE 29/30); no focal deficits

### Workup and Results

**Laboratory Studies:**
| Test | Result | Reference Range |
|------|--------|-----------------|
| Hemoglobin | 11.8 g/dL | 13.5-17.5 g/dL |
| Creatinine | 1.52 mg/dL | 0.7-1.3 mg/dL |
| eGFR | 52 mL/min/1.73m² | >60 mL/min/1.73m² |
| BNP | 685 pg/mL | <100 pg/mL |
| Troponin I | 0.03 ng/mL | <0.04 ng/mL |
| HbA1c | 6.8% | <5.7% (normal) |
| INR | 1.1 | 0.8-1.2 |
| Albumin | 3.6 g/dL | 3.5-5.0 g/dL |

**Imaging/Additional Studies:**
- **Transthoracic echocardiogram:** Severe aortic stenosis — aortic valve area (AVA) 0.7 cm² (severe <1.0 cm²); mean transvalvular gradient 48 mmHg (severe >40 mmHg); peak velocity 4.6 m/s (severe >4.0 m/s); trileaflet valve with heavy calcification; concentric LV hypertrophy (wall thickness 14 mm); LV EF 50% (low-normal); mild aortic regurgitation; mild mitral regurgitation; estimated RVSP 42 mmHg (mild PH); LAVI 42 mL/m² (dilated — diastolic dysfunction)
- **Cardiac catheterization:** No significant coronary artery disease (mild 30% LAD lesion, non-flow-limiting); confirmed AVA 0.72 cm² on invasive hemodynamics; LVEDP 22 mmHg (elevated)
- **CT aorta (gated):** Aortic annulus dimensions: perimeter 78.2 mm, area 456 mm²; trileaflet valve with heavy calcification; no bicuspid morphology; ascending aorta 38 mm (not dilated); iliofemoral arteries: minimal calcification, minimum diameter 7.2 mm bilaterally (adequate for transfemoral TAVR access); no abdominal aortic aneurysm
- **Frailty assessment:** 5-meter gait speed 0.9 m/s (not frail >0.83 m/s); grip strength adequate; no frailty by Fried criteria
- **STS Predicted Risk of Mortality (SAVR):** 4.2% (intermediate risk)
- **EuroSCORE II:** 3.8%

### Clinical Image

![TAVR vs SAVR decision-making for aortic stenosis](case_01_image.jpg)

*Illustration comparing transcatheter aortic valve replacement (TAVR) via transfemoral approach with surgical aortic valve replacement (SAVR) via sternotomy, showing valve positioning, access routes, and key anatomical considerations. Source: Educational illustration.*

### Diagnosis
**Severe Symptomatic Degenerative Calcific Aortic Stenosis (Trileaflet) — NYHA Class III, Intermediate Surgical Risk**

**Key Diagnostic Criteria:**
- Severe AS by all echocardiographic criteria: AVA <1.0 cm², mean gradient >40 mmHg, peak velocity >4.0 m/s
- Symptomatic: exertional dyspnea (NYHA III), exertional near-syncope, exertional angina
- Confirmed by invasive hemodynamic assessment
- No significant coronary artery disease requiring concurrent CABG
- STS score 4.2% — intermediate surgical risk

### Treatment Plan
1. **Heart Team discussion (multidisciplinary — mandatory for valve intervention decisions):**
   - Cardiothoracic surgeon, interventional cardiologist, imaging cardiologist, cardiac anesthesiologist, geriatrician
   - Decision: TAVR recommended based on: age 78, intermediate surgical risk, favorable transfemoral anatomy, trileaflet valve, no concurrent CABG indication, patient preference for faster recovery
   - SAVR would also be reasonable and was discussed; advantages of SAVR include: longer-term durability data, ability to address concurrent pathology, lower rates of paravalvular leak and permanent pacemaker
   - Shared decision-making with patient: patient prefers TAVR given faster recovery, desire to continue writing project, living alone

2. **Pre-procedural optimization:**
   - Discontinue apixaban 48 hours pre-procedure
   - Discontinue metformin morning of procedure
   - Hold aspirin; continue metoprolol
   - Dental clearance (endocarditis prevention)
   - Pre-hydration protocol for CKD (N-acetylcysteine + isotonic bicarbonate before contrast)

3. **TAVR procedure plan:**
   - Transfemoral approach (bilateral femoral arteries adequate at 7.2 mm)
   - Valve sizing: 26 mm self-expanding or balloon-expandable prosthesis based on CT annular dimensions
   - General anesthesia vs. conscious sedation (center-dependent; patient preference considered)
   - Intra-procedural TEE for valve positioning and assessment of paravalvular leak

4. **Post-procedural management:**
   - ICU monitoring 12-24 hours; telemetry for 48 hours
   - Serial ECGs monitoring for conduction disturbances (new LBBB, high-degree AV block — pacemaker needed in ~10-20% post-TAVR)
   - Echocardiogram before discharge: assess prosthetic valve function, paravalvular leak
   - Dual antiplatelet therapy: aspirin 81 mg + clopidogrel 75 mg for 3-6 months, then aspirin alone (or resume apixaban for atrial fibrillation with aspirin only — per recent trial data favoring OAC monotherapy)
   - Anticipated discharge: day 2-3 post-procedure
   - Cardiac rehabilitation referral

5. **Long-term follow-up:**
   - Echocardiogram at 30 days, 1 year, and annually thereafter
   - Endocarditis prophylaxis for dental procedures (lifelong)
   - Monitor for structural valve deterioration (estimated bioprosthetic valve durability: 10-15+ years with current-generation TAVR valves)
   - Annual assessment of conduction system (delayed pacemaker requirement can occur)

### Key Learning Points
- Severe aortic stenosis is defined by AVA <1.0 cm², mean gradient >40 mmHg, and peak velocity >4.0 m/s; once symptoms develop (the classic triad of angina, syncope, and heart failure), prognosis without intervention is poor (2-year mortality ~50%)
- The Heart Team approach is mandated by guidelines for all valve intervention decisions; TAVR and SAVR are both Class I recommendations for symptomatic severe AS, with the choice influenced by surgical risk, anatomy, age, durability considerations, and patient preferences
- TAVR has become the dominant approach for patients aged >65 with intermediate or higher surgical risk; randomized trials (PARTNER 3, Evolut Low Risk) have shown non-inferiority or superiority of TAVR even in low-risk patients, though long-term durability data beyond 5-10 years is still maturing
- Key TAVR-specific complications include paravalvular leak (2-5%), new permanent pacemaker requirement (10-20% depending on valve type), stroke (1-3%), and vascular access complications; SAVR has higher rates of bleeding, atrial fibrillation, and prolonged recovery
- Frailty assessment is critical in elderly patients: the STS score alone may underestimate risk in frail patients; gait speed, grip strength, cognitive function, and nutritional status should inform the Heart Team decision

---

## Case 2: Coronary Artery Bypass Grafting

### Patient Presentation
**Demographics:** 58-year-old male construction company owner

**Chief Complaint:** "I had a heart attack 2 weeks ago, and the cardiologist says I need bypass surgery because stents won't work for my blockages."

**History of Present Illness:**
Mr. S.B. presented to the emergency department 2 weeks ago with acute onset crushing substernal chest pain radiating to his left arm and jaw, diaphoresis, and nausea. ECG showed ST elevation in leads V1-V4 and he was taken emergently for primary PCI. Angiography revealed a thrombotic occlusion of the mid-LAD (culprit lesion), which was stented (drug-eluting stent) with restoration of TIMI 3 flow. However, significant additional disease was identified: 80% stenosis of the proximal LAD (upstream of stent), 90% ostial circumflex stenosis, 85% stenosis of the first obtuse marginal branch, 75% stenosis of the proximal RCA, and 70% distal RCA stenosis (SYNTAX score: 33 — high).

The interventional cardiologist and Heart Team recommended surgical revascularization (CABG) for the non-culprit disease given the high SYNTAX score, left main equivalent disease pattern, diabetes mellitus, and complexity of the lesions. Mr. S.B. was stabilized medically and now presents to the cardiothoracic surgery clinic for pre-operative evaluation.

He reports no recurrent chest pain since the MI and PCI. He is anxious about surgery, particularly about the sternotomy and recovery time. He needs to return to work as his business depends on his active involvement.

**Past Medical History:**
- Acute anterior STEMI (2 weeks ago — treated with primary PCI to mid-LAD)
- Type 2 diabetes mellitus (15 years, on insulin)
- Hypertension (20 years)
- Hyperlipidemia
- Obesity
- Peripheral arterial disease (ABI 0.72 bilaterally, intermittent claudication)
- Obstructive sleep apnea (on CPAP)
- Former smoker (35 pack-years, quit 2 years ago)

**Medications:**
- Aspirin 81 mg daily
- Ticagrelor 90 mg BID (post-PCI — will be held pre-CABG)
- Atorvastatin 80 mg daily
- Metoprolol succinate 100 mg daily
- Lisinopril 20 mg daily
- Insulin glargine 32 units nightly
- Insulin lispro sliding scale with meals
- Eplerenone 25 mg daily (post-MI with reduced EF)

**Social History:**
- Former smoker: 35 pack-years (quit 2 years ago)
- Rare alcohol
- Married, 3 children (youngest age 16)
- Owns and operates construction company — physically demanding oversight role
- Uses CPAP nightly for OSA (AHI 32 pre-CPAP)
- High-stress lifestyle; minimal regular exercise prior to MI

**Family History:**
- Father: MI at age 52 (survived, died of CHF age 71)
- Mother: type 2 diabetes, died of stroke age 68
- Two brothers: both with CAD (one with prior CABG age 55)

### Physical Examination
- **Vital Signs:** BP 126/78 mmHg, HR 68 bpm, RR 14, SpO2 97% on room air, Temp 36.7°C, BMI 33.8 kg/m², Height 178 cm, Weight 107 kg
- **General:** Obese, well-appearing male in no acute distress; anxious
- **Cardiovascular:** Regular rate and rhythm; S1, S2 normal; soft S3 gallop at apex; no murmurs; JVP 8 cm (mildly elevated); right femoral artery access site from PCI: healing well, no hematoma, no bruit
- **Pulmonary:** Clear to auscultation; no crackles or wheeze
- **Abdomen:** Obese, soft, non-tender; no hepatomegaly
- **Extremities:** 1+ bilateral pedal edema; diminished dorsalis pedis and posterior tibial pulses bilaterally (PAD); saphenous veins palpable bilaterally (conduit assessment)
- **Neurological:** Alert and oriented; no carotid bruits; no focal deficits
- **Sternal/chest wall:** No prior sternotomy; adequate body habitus for median sternotomy

### Workup and Results

**Laboratory Studies:**
| Test | Result | Reference Range |
|------|--------|-----------------|
| Hemoglobin | 13.2 g/dL | 13.5-17.5 g/dL |
| Platelet count | 228 x 10⁹/L | 150-400 x 10⁹/L |
| Creatinine | 1.1 mg/dL | 0.7-1.3 mg/dL |
| eGFR | 72 mL/min/1.73m² | >60 mL/min/1.73m² |
| HbA1c | 8.4% | <5.7% (normal) |
| BNP | 420 pg/mL | <100 pg/mL |
| LDL | 68 mg/dL | <70 mg/dL |
| Albumin | 3.8 g/dL | 3.5-5.0 g/dL |
| INR | 1.0 | 0.8-1.2 |

**Imaging/Additional Studies:**
- **Coronary angiography (2 weeks ago):** Mid-LAD: patent DES; Proximal LAD: 80% stenosis (diffuse, calcified); Ostial LCx: 90% stenosis; OM1: 85% stenosis; Proximal RCA: 75% stenosis; Distal RCA: 70% stenosis; SYNTAX score: 33 (high — favors CABG)
- **Echocardiogram (post-MI, day 5):** EF 40% (reduced — anterior wall hypokinesis); LV dilation (LVEDD 58 mm); mild mitral regurgitation (functional); no LV thrombus; no pericardial effusion
- **Carotid duplex ultrasound:** <50% stenosis bilaterally (no intervention needed)
- **Lower extremity ABI:** 0.72 right, 0.74 left (moderate PAD — assess conduit implications)
- **Pulmonary function tests:** FEV1 78% predicted, FVC 80% predicted, FEV1/FVC 0.82 (mildly reduced — acceptable for surgery)
- **Bilateral saphenous vein mapping (duplex ultrasound):** Right great saphenous vein: suitable caliber (3.5-4.0 mm throughout), no varicosities; Left great saphenous vein: suitable but smaller caliber (2.8-3.2 mm); bilateral radial arteries: Allen test positive bilaterally, right radial artery 2.8 mm diameter (suitable for radial artery graft)
- **STS Predicted Risk of Mortality:** 2.1% (low-intermediate risk)

### Clinical Image

![Coronary artery bypass graft configuration](case_02_image.jpg)

*Illustration showing a typical multi-vessel CABG configuration with left internal mammary artery (LIMA) to LAD, radial artery graft to obtuse marginal, and saphenous vein graft to right coronary artery, with on-pump cardiopulmonary bypass circuit depicted. Source: Educational illustration.*

### Diagnosis
**Multivessel Coronary Artery Disease (Three-Vessel + Left Main Equivalent Pattern) — Post-Anterior STEMI with Reduced Ejection Fraction — Indication for Surgical Revascularization (CABG)**

**Key Diagnostic Criteria:**
- High SYNTAX score (33) — randomized trials demonstrate survival benefit of CABG over PCI for SYNTAX >32 (SYNTAX trial, EXCEL trial, NOBLE trial)
- Three-vessel disease with left main equivalent anatomy (proximal LAD + ostial circumflex)
- Diabetes mellitus — FREEDOM trial demonstrated survival benefit of CABG over PCI in diabetic patients with multivessel disease
- Complex, calcified, diffuse lesions not amenable to complete revascularization with PCI
- Reduced EF (40%) post-MI — CABG with LIMA to LAD provides survival benefit in patients with reduced LV function (STICH trial)

### Treatment Plan
1. **Pre-operative optimization (2-4 week window post-MI):**
   - Discontinue ticagrelor 5 days pre-surgery (bleeding risk reduction; aspirin continued)
   - Optimize glycemic control: target glucose 110-180 mg/dL perioperatively; endocrinology consultation for insulin adjustment
   - Continue statin, beta-blocker, ACE inhibitor through morning of surgery
   - CPAP compliance optimization; bring CPAP to hospital for post-operative use
   - Pre-operative shower with chlorhexidine night before and morning of surgery (SSI prevention)
   - Incentive spirometry training pre-operatively
   - Type and screen 2 units pRBCs

2. **Surgical plan:**
   - Median sternotomy approach
   - Cardiopulmonary bypass with aortic cannulation and bicaval venous cannulation
   - Moderate systemic hypothermia (32°C)
   - Cardioplegic arrest with antegrade and retrograde blood cardioplegia
   - **Graft configuration (total arterial preferred strategy):**
     - LIMA (left internal mammary artery) → LAD (gold standard, >95% 10-year patency)
     - Right radial artery → OM1 (second arterial conduit — superior long-term patency vs. SVG in patients <70)
     - SVG (right great saphenous vein) → RCA (PDA target)
   - Inspect mid-LAD stent area; graft distal to stented segment
   - Estimated bypass time: 90-120 minutes; cross-clamp time: 60-80 minutes

3. **Intra-operative considerations:**
   - TEE for LV function assessment, valve competence, cannulation site evaluation, de-airing
   - Epiaortic ultrasound to identify safe cannulation/cross-clamp site (minimize stroke risk)
   - Strict glycemic control (insulin drip targeting 110-180 mg/dL)
   - Cell saver for blood conservation

4. **Post-operative management:**
   - ICU: mechanical ventilation (extubation within 4-8 hours if stable — enhanced recovery protocol)
   - Hemodynamic targets: MAP 65-80 mmHg, HR <90 bpm, CVP 8-12 mmHg, CI >2.2 L/min/m²
   - Chest tubes (mediastinal and pleural) — remove when output <200 mL/12 hr
   - Temporary epicardial pacing wires (remove day 3-4)
   - DVT prophylaxis: compression devices intra-op, heparin 5000 units SC TID starting 6 hours post-op
   - Restart aspirin within 6 hours post-op; ticagrelor NOT resumed (replaced by aspirin for existing LAD stent)
   - Sternal precautions: no lifting >5 lbs for 8 weeks; pillow splinting for cough
   - CPAP use post-extubation with sternal precautions awareness

5. **Discharge and rehabilitation:**
   - Anticipated hospital stay: 5-7 days
   - Phase I cardiac rehabilitation in hospital (ambulation, stair training)
   - Phase II outpatient cardiac rehabilitation starting 2-4 weeks post-discharge (12-week program)
   - Return to driving: 4-6 weeks; return to full work activities: 8-12 weeks
   - Aggressive secondary prevention: statin (target LDL <70), blood pressure control, diabetes management (target HbA1c <7%), smoking cessation maintenance, weight loss, Mediterranean diet
   - Follow-up: surgeon at 2 weeks (wound check), cardiologist at 4 weeks, then every 3-6 months first year

### Key Learning Points
- CABG provides a survival benefit over PCI in patients with multivessel disease and high SYNTAX scores (>32), left main disease, diabetes with multivessel disease, and reduced LV function — these indications are supported by Level A evidence from multiple randomized trials
- The LIMA-to-LAD graft is the cornerstone of CABG with >95% patency at 10 years; arterial grafts (radial artery, right IMA) provide superior long-term patency compared to saphenous vein grafts and should be maximized in appropriate patients (total arterial revascularization strategy)
- Timing of CABG after STEMI is optimized at 3-7 days post-MI when feasible (allows myocardial recovery and inflammation resolution while preventing recurrent events); urgent CABG (<48 hours) carries higher mortality but may be necessary for specific indications (left main disease, cardiogenic shock, mechanical complications)
- Perioperative glycemic control in diabetic patients undergoing CABG significantly reduces sternal wound infection, mediastinitis, and mortality; continuous insulin infusion targeting 110-180 mg/dL is standard of care
- Enhanced recovery after cardiac surgery (ERACS) protocols including early extubation, early mobilization, multimodal analgesia (avoiding excess opioids), and pre-operative patient education reduce hospital stay, complications, and improve patient satisfaction

---

## Case 3: Lung Cancer Lobectomy

### Patient Presentation
**Demographics:** 64-year-old female retired schoolteacher

**Chief Complaint:** "They found a spot on my lung during a screening CT — my doctor says it might be cancer."

**History of Present Illness:**
Mrs. P.G. underwent a low-dose CT chest as part of lung cancer screening (she meets USPSTF criteria: age 50-80, 30+ pack-year smoking history, quit within past 15 years). The scan identified a 2.8 cm spiculated nodule in the right upper lobe with associated ground-glass component. A PET-CT was performed showing intense FDG uptake in the nodule (SUVmax 8.4) with no mediastinal lymph node uptake and no distant metastatic disease.

A CT-guided percutaneous core needle biopsy confirmed lung adenocarcinoma. Molecular testing revealed KRAS G12C mutation, PD-L1 TPS 30%, no EGFR/ALK/ROS1 alterations. Clinical staging: cT1cN0M0, Stage IA3.

She is referred to thoracic surgery for evaluation of surgical resection. She is asymptomatic from the lung nodule — no cough, hemoptysis, dyspnea, chest pain, or weight loss. She reports good exercise tolerance, walking 2-3 miles daily with her dog without limitation.

**Past Medical History:**
- COPD (moderate; FEV1 68% predicted on most recent PFTs 8 months ago)
- Hypertension (well-controlled)
- Osteoporosis (vertebral compression fracture T12, 3 years ago)
- Gastroesophageal reflux disease
- Depression (well-managed)
- Former smoker: 40 pack-years (1 pack/day x 40 years, quit 4 years ago)

**Medications:**
- Tiotropium 18 mcg inhaled daily
- Albuterol 90 mcg PRN (uses 2-3x/week)
- Amlodipine 10 mg daily
- Alendronate 70 mg weekly
- Omeprazole 20 mg daily
- Escitalopram 10 mg daily
- Calcium 600 mg + Vitamin D 800 IU daily

**Social History:**
- Former smoker: 40 pack-years (quit 4 years ago); no secondhand smoke exposure currently
- No alcohol
- Widowed 6 years ago; lives alone with dog
- Active in church community and book club
- Retired elementary school teacher; volunteers at library
- Two adult daughters, supportive

**Family History:**
- Father: lung cancer (diagnosed age 62, died age 64 — smoker)
- Mother: COPD (died age 78)
- Sister: breast cancer (survivor, age 70)

### Physical Examination
- **Vital Signs:** BP 132/76 mmHg, HR 72 bpm, RR 16, SpO2 95% on room air, Temp 36.7°C, BMI 23.4 kg/m², Height 162 cm, Weight 61.5 kg
- **General:** Well-appearing, well-nourished woman in no acute distress; appears younger than stated age
- **Pulmonary:** Mild bilateral end-expiratory wheeze; slightly prolonged expiratory phase; breath sounds otherwise clear; no crackles; chest wall symmetric, no palpable masses
- **Cardiovascular:** Regular rate and rhythm, no murmurs, no JVD
- **Lymph nodes:** No palpable cervical, supraclavicular, or axillary lymphadenopathy
- **Extremities:** No clubbing (significant — suggests absence of advanced disease); no edema
- **Musculoskeletal:** Mild thoracic kyphosis; no bony tenderness
- **Neurological:** Alert, oriented; no focal deficits; normal gait; no signs of paraneoplastic syndrome

### Workup and Results

**Laboratory Studies:**
| Test | Result | Reference Range |
|------|--------|-----------------|
| CBC | WNL | - |
| Hemoglobin | 13.8 g/dL | 12.0-15.5 g/dL |
| Creatinine | 0.8 mg/dL | 0.6-1.1 mg/dL |
| Albumin | 4.2 g/dL | 3.5-5.0 g/dL |
| LDH | 198 U/L | 140-280 U/L |
| Calcium | 9.4 mg/dL | 8.5-10.5 mg/dL |
| ALT/AST | 22/18 U/L | 7-56 / 10-40 U/L |
| CEA | 4.8 ng/mL | <3.0 ng/mL (smoker <5.0) |

**Imaging/Additional Studies:**
- **Low-dose CT chest (screening):** 2.8 cm spiculated solid nodule with partial ground-glass component (part-solid) in right upper lobe, posterior segment; no mediastinal or hilar lymphadenopathy; no pleural effusion; emphysematous changes bilateral upper lobes (centrilobular)
- **PET-CT:** Hypermetabolic right upper lobe nodule (SUVmax 8.4); no FDG-avid mediastinal or hilar lymph nodes; no distant metastatic disease; liver, adrenals, bone — no abnormal uptake
- **MRI brain (with contrast):** No intracranial metastases
- **CT-guided biopsy pathology:** Lung adenocarcinoma, acinar predominant; molecular: KRAS G12C mutation; PD-L1 TPS 30%; EGFR wild-type; ALK negative; ROS1 negative
- **Pulmonary function tests (pre-operative):**
  - FEV1: 1.76 L (68% predicted)
  - FVC: 2.82 L (85% predicted)
  - FEV1/FVC: 0.62 (obstructive pattern)
  - DLCO: 72% predicted
  - Predicted postoperative (ppo) FEV1 after RUL lobectomy: 1.41 L (54% predicted) — using segment counting method (RUL = 3/20 segments removed from right lung contribution)
  - ppo DLCO: 58% predicted
- **Quantitative perfusion lung scan:** Right lung perfusion 55%, left lung 45%; right upper lobe contributes 18% of total perfusion; ppo FEV1 (perfusion-based): 1.44 L (56% predicted) — adequate for lobectomy (threshold >40% predicted or >0.8 L)
- **Cardiopulmonary exercise testing (CPET):** VO2max 18.2 mL/kg/min (>15 mL/kg/min = acceptable for lobectomy; >20 = low risk)
- **Stair climb test:** 5 flights without stopping (good surgical candidacy)
- **EBUS (endobronchial ultrasound) mediastinal staging:** Stations 4R, 7, 10R sampled — all negative for malignancy (confirmed N0 status)

### Clinical Image

![Lung cancer staging and VATS lobectomy approach](case_03_image.jpg)

*Illustration showing the right upper lobe lung adenocarcinoma with staging workup summary, planned video-assisted thoracoscopic surgery (VATS) lobectomy port placement, and mediastinal lymph node station map for systematic dissection. Source: Educational illustration.*

### Diagnosis
**Right Upper Lobe Lung Adenocarcinoma, cT1cN0M0, Stage IA3 (AJCC 8th Edition) — KRAS G12C Mutant, Surgical Candidate**

**Key Diagnostic Criteria:**
- Tissue-confirmed lung adenocarcinoma on CT-guided biopsy
- Tumor size 2.8 cm (T1c: >2 cm to ≤3 cm)
- No lymph node involvement on PET-CT and confirmed by EBUS (N0)
- No distant metastases on PET-CT and brain MRI (M0)
- Stage IA3 per AJCC 8th edition
- Physiologically fit for lobectomy: ppo FEV1 56% predicted (>40% threshold), VO2max 18.2 mL/kg/min (>15 threshold), adequate functional capacity

### Treatment Plan
1. **Pre-operative optimization (1-2 weeks):**
   - Smoking cessation confirmation and counseling reinforcement (already quit 4 years)
   - Pulmonary prehabilitation: incentive spirometry (10 repetitions/hour while awake), walking program intensification, inspiratory muscle training
   - Optimize bronchodilator therapy: ensure tiotropium and albuterol PRN are continued through day of surgery
   - Hold alendronate 1 week pre-op (esophageal irritation risk with positioning)
   - Nutritional optimization: high-protein diet; albumin adequate at 4.2
   - Anesthesia pre-operative assessment with focus on airway and lung isolation strategy

2. **Surgical procedure:**
   - **Video-Assisted Thoracoscopic Surgery (VATS) Right Upper Lobectomy** with systematic mediastinal lymph node dissection
   - Preferred approach: 3-port VATS or uniportal VATS (surgeon preference/experience)
   - Lung isolation: double-lumen endotracheal tube for one-lung ventilation
   - Complete anatomic lobectomy: individual ligation/stapling of RUL pulmonary artery branches (truncus anterior, ascending artery), RUL pulmonary vein, and RUL bronchus
   - Fissure completion with endoscopic stapler
   - Systematic lymph node dissection: stations 2R, 4R, 7, 8, 9, 10R (minimum 3 N2 stations sampled per guidelines)
   - Single chest tube placement to apex
   - Specimen extraction via utility incision; send for permanent pathology with margins

3. **Intra-operative considerations:**
   - Protective one-lung ventilation (tidal volume 4-5 mL/kg IBW, PEEP 5 cmH2O)
   - Avoid excessive fluid administration (pulmonary edema risk in remaining lung)
   - Multimodal analgesia: paravertebral or intercostal nerve blocks with liposomal bupivacaine; avoid excessive opioids
   - Extubation in the operating room (ERAS protocol)

4. **Post-operative management:**
   - Enhanced Recovery After Thoracic Surgery (ERATS) protocol
   - Ambulation day 0 (evening of surgery)
   - Incentive spirometry every 1-2 hours while awake
   - Pain management: multimodal (acetaminophen scheduled, NSAIDs, gabapentin, PCA or low-dose IV opioid for breakthrough only)
   - Chest tube management: water seal (not suction) protocol; remove when output <200 mL/24 hr, no air leak, lung expanded on CXR
   - VTE prophylaxis: enoxaparin 40 mg SC daily starting 6-12 hours post-op
   - Anticipated discharge: post-operative day 2-4

5. **Pathology and adjuvant therapy decisions:**
   - If final pathology confirms pT1cN0M0 (Stage IA3): observation with surveillance CT per NCCN guidelines (CT chest Q6 months x 2 years, then annually)
   - If unexpected nodal upstaging (pN1 or pN2): adjuvant chemotherapy (cisplatin-based doublet x 4 cycles) ± radiation for N2 disease; consider adjuvant osimertinib trial eligibility (though EGFR wild-type, KRAS G12C targeted agents like sotorasib may have future adjuvant roles)
   - If Stage IB-IIIA on final pathology: ctDNA-guided adjuvant therapy decision (IMpower010 for PD-L1+ tumors: atezolizumab adjuvant immunotherapy)
   - Ongoing lung cancer screening for remaining lung tissue

6. **Surveillance schedule:**
   - CT chest with contrast: every 6 months for years 1-2, then annually for years 3-5, then as clinically indicated
   - CEA at baseline and serially if elevated (limited utility)
   - Annual PFTs to monitor remaining lung function
   - Continued smoking abstinence support

### Key Learning Points
- Low-dose CT lung cancer screening reduces lung cancer mortality by 20% (NLST trial) and up to 24% (NELSON trial); anatomic lobectomy with systematic lymph node dissection is the standard of care for stage I-II NSCLC in physiologically fit patients
- Pre-operative physiological assessment for lobectomy requires three pillars: (1) spirometry with predicted postoperative FEV1 and DLCO (>40% predicted = adequate), (2) cardiopulmonary exercise testing with VO2max (>15 mL/kg/min = acceptable, >20 = low risk), and (3) functional assessment (stair climb test — 3+ flights correlates with acceptable risk)
- VATS lobectomy is associated with less pain, shorter hospital stay, fewer complications, better preserved pulmonary function, and equivalent oncological outcomes compared to open thoracotomy; it is the preferred approach when technically feasible
- Systematic mediastinal lymph node dissection (not just sampling) is essential for accurate staging and may provide therapeutic benefit; upstaging from cN0 to pN1/N2 occurs in 10-15% of cases, fundamentally changing adjuvant therapy decisions
- KRAS G12C mutation is the most common actionable mutation in lung adenocarcinoma (~13%); sotorasib and adagrasib are FDA-approved for advanced/metastatic disease, with adjuvant trials ongoing — molecular profiling at diagnosis informs both immediate and future treatment decisions