Lung resection procedures — MCQs

10 questions

A 57-year-old man presents to his family physician for a routine exam. He feels well and reports no new complaints since his visit last year. Last year, he had a colonoscopy which showed no polyps, a low dose chest computerized tomography (CT) scan that showed no masses, and routine labs which showed a fasting glucose of 93 mg/dL. He is relatively sedentary and has a body mass index (BMI) of 24 kg/m^2. He has a history of using methamphetamines, alcohol (4-5 drinks per day since age 30), and tobacco (1 pack per day since age 18), but he joined Alcoholics Anonymous and has been in recovery, not using any of these for the past 7 years. Which of the following is indicated at this time?

A 56-year-old previously healthy woman with no other past medical history is post-operative day one from an open reduction and internal fixation of a fractured right radius and ulna after a motor vehicle accident. What is one of the primary ways of preventing postoperative pneumonia in this patient?

A 61-year-old man comes to the physician because of a 3-month history of worsening exertional dyspnea and a persistent dry cough. For 37 years he has worked in a naval shipyard. He has smoked 1 pack of cigarettes daily for the past 40 years. Pulmonary examination shows fine bibasilar end-expiratory crackles. An x-ray of the chest shows diffuse bilateral infiltrates predominantly in the lower lobes and pleural reticulonodular opacities. A CT scan of the chest shows pleural plaques and subpleural linear opacities. The patient is most likely to develop which of the following conditions?

A 35-year-old woman volunteers for a study on respiratory physiology. Pressure probes A and B are placed as follows: Probe A: between the parietal and visceral pleura Probe B: within the cavity of an alveolus The probes provide a pressure reading relative to atmospheric pressure. To obtain a baseline reading, she is asked to sit comfortably and breathe normally. Which of the following sets of values will most likely be seen at the end of inspiration?

A 62-year-old man comes to the physician for a follow-up examination after having been diagnosed with stage II adenocarcinoma of the left lower lung lobe without evidence of distant metastases 1 week ago following an evaluation for a chronic cough. He has hypertension and type 2 diabetes mellitus. He has smoked one pack of cigarettes daily for the past 40 years. His current medications include metformin, sitagliptin, and enalapril. He is 177 cm (5 ft 10 in) tall and weighs 65 kg (143 lb); BMI is 20.7 kg/m2. He appears lethargic. Vital signs are within normal limits. Pulse oximetry shows an oxygen saturation of 98%. Examination shows inspiratory wheezing at the left lung base. The remainder of the examination shows no abnormalities. A complete blood count and serum concentrations of electrolytes, creatinine, glucose, and liver enzymes are within the reference range. Spirometry shows an FEV1 of 1.6 L. The diffusing lung capacity for carbon monoxide (DLCO) is 66% of predicted. Which of the following is the most appropriate next step in the management of this patient?

In which of the following pathological states would the oxygen content of the trachea resemble the oxygen content in the affected alveoli?

A 56-year-old man presents to the emergency department with severe chest pain and a burning sensation. He accidentally drank a cup of fluid at his construction site 2 hours ago. The liquid was later found to contain lye. On physical examination, his blood pressure is 100/57 mm Hg, respiratory rate is 21/min, pulse is 84/min, and temperature is 37.7°C (99.9°F). The patient is sent immediately to the radiology department. The CT scan shows air in the mediastinum, and a contrast swallow study confirms the likely diagnosis. Which of the following is the best next step in the management of this patient’s condition?

A 70-year-old man with severe ischemic cardiomyopathy (EF 25%) has recurrent ventricular tachycardia despite optimal medical therapy and ICD placement. Cardiac MRI shows a large anteroseptal scar with viable myocardium in the lateral and inferior walls. He has three-vessel coronary disease. His daughter is advocating for heart transplantation, but he has multiple comorbidities including obesity (BMI 37) and active tobacco use. Evaluate the management priority and rationale.

A 49-year-old woman with myasthenia gravis undergoes CT chest showing a 5 cm anterior mediastinal mass with irregular borders. Biopsy confirms thymoma (WHO type B2). She has well-controlled myasthenic symptoms on pyridostigmine. Staging shows no distant metastases, but the mass abuts the pericardium without clear invasion. Evaluate the optimal treatment approach.

Q10

A 58-year-old man with coronary artery disease requires CABG. Preoperative angiography shows 90% left main stenosis, 95% proximal LAD stenosis, 80% circumflex stenosis, and chronic total occlusion of the RCA with collaterals. He has diabetes, renal insufficiency (Cr 2.1), and previous stroke. Evaluate the optimal grafting strategy to maximize long-term patency and outcomes.

Lung resection procedures US Medical PG Practice Questions and MCQs

Question 1: A 57-year-old man presents to his family physician for a routine exam. He feels well and reports no new complaints since his visit last year. Last year, he had a colonoscopy which showed no polyps, a low dose chest computerized tomography (CT) scan that showed no masses, and routine labs which showed a fasting glucose of 93 mg/dL. He is relatively sedentary and has a body mass index (BMI) of 24 kg/m^2. He has a history of using methamphetamines, alcohol (4-5 drinks per day since age 30), and tobacco (1 pack per day since age 18), but he joined Alcoholics Anonymous and has been in recovery, not using any of these for the past 7 years. Which of the following is indicated at this time?

A. Colonoscopy
B. Chest computerized tomography (CT) scan (Correct Answer)
C. Abdominal ultrasound
D. Chest radiograph
E. Fasting glucose

Explanation: ***Chest computerized tomography (CT) scan*** - This patient has a significant **smoking history** (1 pack per day since age 18 = **39 pack-years**) and is 57 years old, placing him in a high-risk group for **lung cancer**. - Annual low-dose CT screening for lung cancer is recommended for individuals aged 50-80 with a 20 pack-year smoking history who currently smoke or have quit within the past 15 years. - He meets all criteria: age 57, 39 pack-years, and quit only 7 years ago (within the 15-year window). - Since he had screening **last year** with no masses, this year's visit represents the appropriate time for his **annual follow-up screening**. *Colonoscopy* - The patient had a colonoscopy last year with **no polyps**, suggesting he is at average risk for colorectal cancer. - For individuals at average risk with normal findings, repeat screening colonoscopy is typically recommended every **10 years** (or every 5 years for flexible sigmoidoscopy), not annually. *Abdominal ultrasound* - One-time abdominal ultrasound screening for **abdominal aortic aneurysm (AAA)** is recommended for men aged 65-75 who have ever smoked. - This patient is only 57 years old and does not yet meet the age criteria for AAA screening. *Chest radiograph* - While a chest radiograph can identify some lung abnormalities, a **low-dose CT scan** is far more sensitive and specific for detecting early-stage lung cancer in high-risk populations. - Chest radiography is **not recommended** as a screening tool for lung cancer due to its lower sensitivity and lack of mortality benefit in trials. *Fasting glucose* - The patient had a **normal fasting glucose** of 93 mg/dL last year, and there are no new symptoms suggestive of diabetes. - For asymptomatic adults with normal glucose, diabetes screening is typically repeated every **3 years**. - Annual re-screening is not indicated without new risk factors or symptoms.

Question 2: A 56-year-old previously healthy woman with no other past medical history is post-operative day one from an open reduction and internal fixation of a fractured right radius and ulna after a motor vehicle accident. What is one of the primary ways of preventing postoperative pneumonia in this patient?

A. Shallow breathing exercises
B. Incentive spirometry (Correct Answer)
C. Outpatient oral antibiotics
D. Hyperbaric oxygenation
E. In-hospital intravenous antibiotics

Explanation: ***Incentive spirometry*** - **Incentive spirometry** is a cornerstone of postoperative care, actively encouraging patients to take slow, deep breaths. This expands the lungs and prevents the collapse of alveoli, reducing the risk of **atelectasis** and subsequent **pneumonia**. - Its effectiveness lies in promoting lung aeration and clearing secretions, which are crucial after anesthesia and surgery, especially in patients with reduced mobility or pain. *Shallow breathing exercises* - **Shallow breathing** is insufficient for adequate lung expansion and can actually contribute to **atelectasis** and the pooling of secretions in the lungs. - Effective pulmonary hygiene requires **deep breaths** to maximize alveolar recruitment and prevent respiratory complications. *Outpatient oral antibiotics* - **Prophylactic antibiotics** are typically given around the time of surgery to prevent surgical site infections, not primarily to prevent postoperative pneumonia in an outpatient setting. - Administering antibiotics without a diagnosed infection can lead to **antibiotic resistance** and is not a standard practice for preventing pneumonia unless a specific risk factor or existing infection is identified. *Hyperbaric oxygenation* - **Hyperbaric oxygenation** involves breathing 100% oxygen in a pressurized chamber and is used for conditions like **decompression sickness**, non-healing wounds, or severe infections. - It is not a standard or primary method for preventing postoperative pneumonia, as its mechanism of action is unrelated to common pulmonary hygiene techniques. *In-hospital intravenous antibiotics* - While antibiotics can treat pneumonia, their routine, **prophylactic use** intravenously in-hospital solely for preventing postoperative pneumonia is generally unwarranted and can contribute to **antibiotic resistance**. - Antibiotics are indicated if there is evidence of an active infection, but the primary prevention of pneumonia focuses on mechanical lung expansion and airway clearance.

Question 3: A 61-year-old man comes to the physician because of a 3-month history of worsening exertional dyspnea and a persistent dry cough. For 37 years he has worked in a naval shipyard. He has smoked 1 pack of cigarettes daily for the past 40 years. Pulmonary examination shows fine bibasilar end-expiratory crackles. An x-ray of the chest shows diffuse bilateral infiltrates predominantly in the lower lobes and pleural reticulonodular opacities. A CT scan of the chest shows pleural plaques and subpleural linear opacities. The patient is most likely to develop which of the following conditions?

A. Malignant mesothelioma
B. Spontaneous pneumothorax
C. Bronchogenic carcinoma (Correct Answer)
D. Aspergilloma
E. Mycobacterial infection

Explanation: ***Bronchogenic carcinoma*** - This patient has **asbestosis** from 37 years of shipyard work (asbestos exposure) combined with a **40-pack-year smoking history**, creating a **synergistic risk** for lung cancer. - Asbestos exposure alone increases lung cancer risk **5-fold**, smoking alone increases it **10-fold**, but **combined exposure increases the risk 50-fold** due to synergistic effects. - The chest imaging findings (diffuse bilateral infiltrates, pleural reticulonodular opacities, pleural plaques, and subpleural linear opacities) confirm **asbestosis**, making **bronchogenic carcinoma** the most likely future complication. *Malignant mesothelioma* - While strongly associated with **asbestos exposure**, it is **not synergistic with smoking** and has a lower absolute incidence compared to bronchogenic carcinoma in patients with combined exposures. - Mesothelioma typically presents with **unilateral pleural thickening**, pleural effusion, and chest pain rather than the diffuse parenchymal infiltrates and bibasilar crackles seen here. *Spontaneous pneumothorax* - Characterized by sudden lung collapse with acute chest pain and dyspnea, appearing on imaging as air in the pleural space. - While smoking-related emphysema can lead to bullae rupture and pneumothorax, the primary findings here indicate chronic interstitial lung disease and pleural pathology from asbestos exposure. *Mycobacterial infection* - Would typically present with constitutional symptoms (fever, night sweats, weight loss) and possibly hemoptysis, which are not mentioned in this case. - Imaging usually shows cavitary lesions, nodules, or upper lobe predominance, differing from the diffuse lower lobe infiltrates and pleural plaques characteristic of asbestosis. *Aspergilloma* - A fungal ball within a pre-existing cavity, typically seen in patients with tuberculosis, sarcoidosis, or other chronic cavitary lung diseases. - The clinical presentation and imaging findings, particularly the occupational asbestos exposure and smoking history, point toward malignancy risk rather than fungal colonization.

Question 4: A 35-year-old woman volunteers for a study on respiratory physiology. Pressure probes A and B are placed as follows: Probe A: between the parietal and visceral pleura Probe B: within the cavity of an alveolus The probes provide a pressure reading relative to atmospheric pressure. To obtain a baseline reading, she is asked to sit comfortably and breathe normally. Which of the following sets of values will most likely be seen at the end of inspiration?

A. Probe A: -6 mm Hg; Probe B: 0 mm Hg (Correct Answer)
B. Probe A: 0 mm Hg; Probe B: -1 mm Hg
C. Probe A: -4 mm Hg; Probe B: 0 mm Hg
D. Probe A: -4 mm Hg; Probe B: -1 mm Hg
E. Probe A: -6 mm Hg; Probe B: -1 mm Hg

Explanation: ***Probe A: -6 mm Hg; Probe B: 0 mm Hg*** - At the **end of inspiration**, the **intrapleural pressure (Probe A)** is at its most negative, typically around -6 to -8 cm H2O (equivalent to -4 to -6 mmHg), reflecting the maximum expansion of the thoracic cavity. - At the **end of inspiration**, just before exhalation begins, there is **no airflow**, so the **intrapulmonary pressure (Probe B)** equalizes with atmospheric pressure, resulting in a 0 mm Hg reading. *Probe A: 0 mm Hg; Probe B: -1 mm Hg* - An **intrapleural pressure of 0 mm Hg** would indicate a **pneumothorax** since it should always be negative to prevent lung collapse. - An **intrapulmonary pressure of -1 mm Hg** would indicate that **inspiration is still ongoing**, as air would be flowing into the lungs. *Probe A: -4 mm Hg; Probe B: 0 mm Hg* - While an **intrapulmonary pressure of 0 mm Hg** is correct at the end of inspiration, an **intrapleural pressure of -4 mm Hg** is typical for the **end of expiration (Functional Residual Capacity)** during quiet breathing, not the end of inspiration. - The **intrapleural pressure becomes more negative** during inspiration due to increased thoracic volume, so -4 mm Hg would be insufficient. *Probe A: -4 mm Hg; Probe B: -1 mm Hg* - An **intrapleural pressure of -4 mm Hg** is the normal pressure at the **end of expiration**, not the end of inspiration, where it becomes more negative. - An **intrapulmonary pressure of -1 mm Hg** indicates that **inspiration is still in progress**, not at its end, as air would still be flowing into the lungs. *Probe A: -6 mm Hg; Probe B: -1 mm Hg* - While an **intrapleural pressure of -6 mm Hg** is consistent with the end of inspiration, an **intrapulmonary pressure of -1 mm Hg** means that **airflow is still occurring into the lungs**. - At the **very end of inspiration**, just before the start of exhalation, airflow momentarily ceases, and intrapulmonary pressure becomes zero relative to the atmosphere.

Question 5: A 62-year-old man comes to the physician for a follow-up examination after having been diagnosed with stage II adenocarcinoma of the left lower lung lobe without evidence of distant metastases 1 week ago following an evaluation for a chronic cough. He has hypertension and type 2 diabetes mellitus. He has smoked one pack of cigarettes daily for the past 40 years. His current medications include metformin, sitagliptin, and enalapril. He is 177 cm (5 ft 10 in) tall and weighs 65 kg (143 lb); BMI is 20.7 kg/m2. He appears lethargic. Vital signs are within normal limits. Pulse oximetry shows an oxygen saturation of 98%. Examination shows inspiratory wheezing at the left lung base. The remainder of the examination shows no abnormalities. A complete blood count and serum concentrations of electrolytes, creatinine, glucose, and liver enzymes are within the reference range. Spirometry shows an FEV1 of 1.6 L. The diffusing lung capacity for carbon monoxide (DLCO) is 66% of predicted. Which of the following is the most appropriate next step in the management of this patient?

A. Schedule lobectomy (Correct Answer)
B. Administer cisplatin and vinorelbine
C. Schedule a wedge resection
D. Administer cisplatin and etoposide
E. Radiation therapy

Explanation: ***Schedule lobectomy*** - The patient has **stage II non-small cell lung cancer (adenocarcinoma)** without distant metastases, making surgical resection with **lobectomy** the treatment of choice for curative intent. - While pulmonary function is somewhat impaired (FEV1 and DLCO), his overall status, age, and normal labs suggest he can likely tolerate the procedure. *Administer cisplatin and vinorelbine* - This combination is a common regimen for **adjuvant chemotherapy** following surgical resection in certain stages of NSCLC, or for advanced unresectable disease. - It is not the primary treatment for a resectable stage II cancer; **surgery is preferred for cure**. *Schedule a wedge resection* - A **wedge resection** (sublobar resection) is typically reserved for patients with very small, peripheral tumors or those with severe comorbidities that preclude lobectomy due to poor pulmonary function. - Given the patient's stage II disease and potentially curative intent, a **lobectomy is generally preferred** for better oncologic outcomes. *Administer cisplatin and etoposide* - This chemotherapy regimen is more commonly used for **small cell lung cancer (SCLC)** or for some advanced NSCLC cases, not typically for resectable stage II adenocarcinoma as a primary treatment. - Even if used in NSCLC, it would usually be in the context of advanced disease or as part of a neoadjuvant/adjuvant approach with surgery, not as a standalone initial treatment for resectable disease. *Radiation therapy* - **Radiation therapy** is often used for inoperable tumors, for patients who refuse surgery, or as an adjuvant treatment. - For a resectable stage II NSCLC, **surgery offers the best chance for cure**, making radiation therapy alone less appropriate as the first-line definitive treatment strategy.

Question 6: In which of the following pathological states would the oxygen content of the trachea resemble the oxygen content in the affected alveoli?

A. Emphysema
B. Exercise
C. Pulmonary embolism (Correct Answer)
D. Pulmonary fibrosis
E. Foreign body obstruction distal to the trachea

Explanation: ***Pulmonary embolism*** - A pulmonary embolism blocks **blood flow** to a portion of the lung, creating **dead space ventilation** (high V/Q ratio). - In the affected alveoli, **no blood perfusion** means no oxygen extraction occurs, so the alveolar oxygen content remains **high and similar to tracheal/inspired air**. - This is the classic physiological state where ventilation continues but perfusion is absent, preventing gas exchange. *Foreign body obstruction distal to the trachea* - A complete obstruction **prevents fresh air** from reaching the affected alveoli. - The trapped gas undergoes **resorption atelectasis**: oxygen is absorbed into capillary blood, CO2 diffuses in, and alveolar gas equilibrates with **venous blood** composition. - Alveolar oxygen content becomes **very low**, not similar to tracheal air. *Emphysema* - Emphysema involves destruction of **alveolar walls** and enlargement of airspaces with impaired gas exchange. - While V/Q mismatch occurs, oxygen is still extracted by perfusing blood. - Alveolar oxygen content is **lower than tracheal air** due to ongoing (though inefficient) gas exchange. *Exercise* - During exercise, **oxygen consumption increases** dramatically with enhanced cardiac output and oxygen extraction. - Alveolar oxygen content is **significantly lower** than tracheal air due to increased oxygen uptake by blood. *Pulmonary fibrosis* - Pulmonary fibrosis causes **thickening of the alveolar-capillary membrane**, impairing oxygen diffusion. - Despite diffusion limitation, blood still perfuses the alveoli and extracts oxygen. - Alveolar oxygen content is **lower than tracheal air**, though the A-a gradient is increased.

Question 7: A 56-year-old man presents to the emergency department with severe chest pain and a burning sensation. He accidentally drank a cup of fluid at his construction site 2 hours ago. The liquid was later found to contain lye. On physical examination, his blood pressure is 100/57 mm Hg, respiratory rate is 21/min, pulse is 84/min, and temperature is 37.7°C (99.9°F). The patient is sent immediately to the radiology department. The CT scan shows air in the mediastinum, and a contrast swallow study confirms the likely diagnosis. Which of the following is the best next step in the management of this patient’s condition?

A. Ceftriaxone
B. Oral antidote
C. Dexamethasone
D. Surgical repair (Correct Answer)
E. Nasogastric lavage

Explanation: ***Surgical repair*** - The presence of **mediastinal air** on CT scan and confirmation of **esophageal perforation** by contrast swallow study indicate a surgical emergency. - **Emergency surgical repair** is crucial to prevent widespread mediastinitis, sepsis, and potential mortality from corrosive ingestion. *Ceftriaxone* - While **antibiotics** like Ceftriaxone might be used as adjuncts to prevent infection, they are not the primary treatment for an established esophageal perforation. - Antibiotics alone will not address the structural defect or contain the leakage of corrosive material into the mediastinum. *Oral antidote* - For corrosive ingestions, administering an **oral antidote** is contraindicated as it can worsen tissue damage or induce vomiting, leading to further esophageal injury. - The immediate priority is managing the perforation, not neutralizing the corrosive agent internally. *Dexamethasone* - **Corticosteroids** like dexamethasone are sometimes considered in the management of corrosive ingestions to reduce stricture formation, but their role is controversial and they are not the initial treatment for an acute perforation. - In an active perforation, corticosteroids would not address the immediate life-threatening issue of mediastinal contamination. *Nasogastric lavage* - **Nasogastric lavage** is contraindicated in corrosive ingestions, especially with suspected or confirmed perforation. - Passing a tube could further injure the already damaged tissue and increase the risk of perforation or exacerbate an existing one.

Question 8: A 70-year-old man with severe ischemic cardiomyopathy (EF 25%) has recurrent ventricular tachycardia despite optimal medical therapy and ICD placement. Cardiac MRI shows a large anteroseptal scar with viable myocardium in the lateral and inferior walls. He has three-vessel coronary disease. His daughter is advocating for heart transplantation, but he has multiple comorbidities including obesity (BMI 37) and active tobacco use. Evaluate the management priority and rationale.

A. Left ventricular assist device as destination therapy
B. Catheter ablation of VT with continued ICD monitoring
C. Cardiac resynchronization therapy upgrade and medication adjustment
D. List for heart transplantation immediately given severe cardiomyopathy
E. CABG with surgical ventricular reconstruction and continued medical optimization (Correct Answer)

Explanation: ***CABG with surgical ventricular reconstruction and continued medical optimization*** - The patient has **three-vessel disease** and **viable myocardium** in the lateral and inferior walls; **CABG** addresses the ischemic substrate and potentially improves **LVEF**. - **Surgical ventricular reconstruction (SVR)** addresses the large **anteroseptal scar**, reducing left ventricular volume and providing better geometric stability to mitigate **ventricular tachycardia** (VT). *Left ventricular assist device as destination therapy* - While **LVAD** is an option for end-stage heart failure, the presence of **active tobacco use** and **obesity** (BMI 37) are significant relative contraindications. - **Surgical revascularization** is prioritized when significant **viable myocardium** is present and surgical targets are available. *Catheter ablation of VT with continued ICD monitoring* - **VT ablation** target-treats the arrhythmia but does not address the underlying **remodelling** or **ischemia** causing the progressive cardiomyopathy. - Given the **three-vessel disease**, surgical intervention is more comprehensive for long-term prognosis compared to percutaneous ablation alone. *Cardiac resynchronization therapy upgrade and medication adjustment* - The patient is already on **optimal medical therapy** with an **ICD**; simple medication adjustment is unlikely to control recurrent VT in the setting of structural scar and ischemia. - **CRT** provides limited benefit if the primary issue is a large **anteroseptal scar** and **active ischemia** requiring revascularization. *List for heart transplantation immediately given severe cardiomyopathy* - Direct listing is contraindicated due to **active tobacco use** and a **BMI >35**, which are standard exclusion criteria for transplant programs. - Heart transplantation is considered a last resort after maximizing options like **revascularization** and addressing **modifiable risk factors**.

Question 9: A 49-year-old woman with myasthenia gravis undergoes CT chest showing a 5 cm anterior mediastinal mass with irregular borders. Biopsy confirms thymoma (WHO type B2). She has well-controlled myasthenic symptoms on pyridostigmine. Staging shows no distant metastases, but the mass abuts the pericardium without clear invasion. Evaluate the optimal treatment approach.

A. Thymectomy with possible en bloc pericardial resection, followed by adjuvant radiation (Correct Answer)
B. Increase immunosuppression then delayed surgery in 6 months
C. Radiation therapy alone to preserve myasthenia control
D. Immediate thymectomy followed by observation
E. Neoadjuvant chemotherapy, then thymectomy and adjuvant radiation

Explanation: ***Thymectomy with possible en bloc pericardial resection, followed by adjuvant radiation*** - Complete **surgical resection (R0)** is the cornerstone of treatment for **WHO type B2 thymomas**, especially when the mass is resectable despite abutting local structures like the **pericardium**. - **Adjuvant radiation** is indicated for **Masaoka Stage II/III** disease or high-risk B2 histology to minimize the risk of **local recurrence**. *Increase immunosuppression then delayed surgery in 6 months* - Delaying surgery for a 5 cm **potentially invasive thymoma** allows for tumor progression and increases the risk of higher-stage disease. - **Myasthenia gravis** symptoms are already **well-controlled**, making immediate surgical intervention safe and the preferred priority. *Radiation therapy alone to preserve myasthenia control* - **Radiation alone** is not a curative intent treatment for resectable thymoma and is usually reserved for **unresectable** or medically unfit patients. - Thymectomy is actually a therapeutic part of managing **myasthenia gravis**, often leading to symptomatic improvement or remission. *Immediate thymectomy followed by observation* - Observation alone after surgery is insufficient for **B2 thymomas** that show irregular borders or high-risk features like **pericardial involvement**. - The size over 5 cm and contact with the **pericardium** (Stage IIb/III) necessitate **postoperative radiotherapy** to improve oncologic outcomes. *Neoadjuvant chemotherapy, then thymectomy and adjuvant radiation* - **Neoadjuvant chemotherapy** is typically reserved for tumors deemed **primarily unresectable** on imaging, which is not the case here. - Since the mass only **abuts** the pericardium and has no distant metastases, it is considered **upfront resectable**.

Question 10: A 58-year-old man with coronary artery disease requires CABG. Preoperative angiography shows 90% left main stenosis, 95% proximal LAD stenosis, 80% circumflex stenosis, and chronic total occlusion of the RCA with collaterals. He has diabetes, renal insufficiency (Cr 2.1), and previous stroke. Evaluate the optimal grafting strategy to maximize long-term patency and outcomes.

A. Bilateral internal mammary arteries with supplemental vein grafts
B. Off-pump CABG with sequential vein grafts only
C. LIMA to LAD, radial artery to circumflex, vein graft to RCA (Correct Answer)
D. All saphenous vein grafts to minimize operative time
E. LIMA to LAD, saphenous vein grafts to remaining vessels

Explanation: ***LIMA to LAD, radial artery to circumflex, vein graft to RCA*** - The **LIMA-to-LAD** graft is the gold standard, providing the best long-term patency and survival outcomes in multi-vessel **CABG**. - Using a **radial artery** for the circumflex system (high-grade stenosis) offers superior patency over vein grafts while avoiding the high risk of **sternal wound infection** associated with **BIMA** in diabetic patients. *Bilateral internal mammary arteries with supplemental vein grafts* - While **BIMA** provides excellent patency, it is associated with a significantly increased risk of **sternal dehiscence** and infection in patients with **Diabetes Mellitus**. - The benefit of a second arterial graft is better achieved with the **radial artery** in this high-risk comorbid profile. *Off-pump CABG with sequential vein grafts only* - **Sequential vein grafts** have lower long-term patency compared to arterial conduits and do not capitalize on the survival benefit of the **LIMA-to-LAD**. - Off-pump surgery might reduce some risks but using only vein grafts is suboptimal for a 58-year-old with **long-term** survival goals. *All saphenous vein grafts to minimize operative time* - **Saphenous vein grafts (SVG)** have much higher failure rates (approx. 50% at 10 years) compared to **internal mammary arteries**. - Minimizing operative time does not justify the poor long-term clinical outcomes and higher **re-intervention rates** associated with an all-SVG strategy. *LIMA to LAD, saphenous vein grafts to remaining vessels* - This is a standard approach, but the addition of a second arterial conduit like the **radial artery** is preferred for younger patients with high-grade stenosis to maximize **patency**. - In the setting of **90% left main** and **80% circumflex** stenosis, the radial artery is more durable than a vein graft for the circumflex target.

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