CSC Case Studies & Practical Application 4 — Questions and Answers
Question 1: A 42-year-old woman with SLE presents with dyspnea and echo showing thickened mitral and aortic leaflets with regurgitation but no vegetations. Blood cultures are negative. What is the most likely diagnosis?
- Infective endocarditis
- Libman-Sacks endocarditis (Correct answer)
- Rheumatic heart disease
- Carcinoid heart disease
Correct answer: Libman-Sacks endocarditis
Libman-Sacks endocarditis is a nonbacterial thrombotic endocarditis associated with SLE, characterized by sterile vegetations typically on both sides of the valve leaflets.
Question 2: A 68-year-old man with prior CABG presents with recurrent angina. Stress imaging reveals ischemia in the LAD territory. Angiography shows patent LIMA-LAD graft with a 90% stenosis of the proximal LAD native vessel proximal to the anastomosis. What is the preferred strategy?
- PCI of the native LAD proximal lesion (Correct answer)
- Redo CABG with new conduit
- Medical therapy escalation only
- PCI of the LIMA-LAD anastomosis
Correct answer: PCI of the native LAD proximal lesion
PCI of the native coronary artery proximal to a patent bypass graft anastomosis is preferred over redo surgery when feasible, avoiding graft manipulation.
Question 3: A 25-year-old man with Marfan syndrome is found to have an aortic root diameter of 4.7 cm on annual surveillance. He is asymptomatic. Which management is most appropriate?
- Elective aortic root replacement (Correct answer)
- Increase surveillance frequency to every 3 months
- Continue annual imaging and maintain current medical therapy
- Prescribe losartan and reimage in 2 years
Correct answer: Elective aortic root replacement
Guidelines recommend prophylactic aortic root replacement in Marfan syndrome when the aortic root diameter reaches ≥4.5 cm, or when growth rate exceeds 0.5 cm/year.
Question 4: A 70-year-old man with known severe AS (AVA 0.65 cm²) and EF 25% presents with mean gradient of only 28 mmHg. What test best differentiates true severe AS from pseudo-severe AS in this context?
- Exercise stress echocardiography
- Dobutamine stress echocardiography (Correct answer)
- Cardiac MRI with gadolinium
- Coronary CT angiography
Correct answer: Dobutamine stress echocardiography
Dobutamine stress echocardiography distinguishes true severe AS (AVA remains low at higher flow) from pseudo-severe AS (AVA increases with dobutamine) in low-flow, low-gradient AS.
Question 5: A 52-year-old woman with HCM and LVOT gradient of 75 mmHg at rest has NYHA class III symptoms despite maximally tolerated disopyramide and metoprolol. What intervention should be considered next?
- Add amiodarone
- Septal reduction therapy (surgical myectomy or alcohol septal ablation) (Correct answer)
- ICD implantation
- Cardiac transplantation
Correct answer: Septal reduction therapy (surgical myectomy or alcohol septal ablation)
Septal reduction therapy (surgical myectomy preferred, or alcohol septal ablation) is indicated for drug-refractory obstructive HCM with severe symptoms.
Question 6: A 58-year-old man with history of IV drug use presents with fever, new murmur, and multiple pulmonary emboli on CT. Echo shows a large vegetation on the tricuspid valve. Blood cultures grow MRSA. What is the best treatment strategy?
- IV vancomycin for 6 weeks; surgery only if fails (Correct answer)
- Immediate surgical tricuspid valve replacement
- IV daptomycin for 2 weeks and discharge with oral antibiotics
- Catheter-based vegetation aspiration
Correct answer: IV vancomycin for 6 weeks; surgery only if fails
Right-sided MRSA endocarditis is initially managed with 6 weeks of IV vancomycin (or daptomycin), with surgery reserved for treatment failure or very large vegetations causing persistent sepsis.
Question 7: A 45-year-old man presents with palpitations and ECG showing a short PR interval, delta waves, and wide QRS. He develops rapid AF with rates >250 bpm. What is the most dangerous drug to administer?
- IV procainamide
- IV ibutilide
- IV adenosine or IV verapamil (Correct answer)
- Electrical cardioversion
Correct answer: IV adenosine or IV verapamil
AV nodal blocking agents (adenosine, verapamil, digoxin) are contraindicated in pre-excited AF as they can accelerate conduction through the accessory pathway, precipitating VF.
CSC Case Studies & Practical Application 4
A 42-year-old woman with SLE presents with dyspnea and echo showing thickened mitral and aortic leaflets with regurgitation but no vegetations.
Blood cultures are negative.
What is the most likely diagnosis?