ITE Valvular Heart Disease Management 6

Question 1

A 55-year-old man with a St. Jude mechanical mitral valve prosthesis on warfarin (INR target 2.5–3.5) requires elective cholecystectomy. His current INR is 3.1. What is the most appropriate perioperative anticoagulation strategy?

Accepted Answer

Bridge with unfractionated heparin infusion after stopping warfarin 5 days preoperatively

Answer

Mechanical mitral valve prostheses carry a high thromboembolic risk (Class I indication for bridging per ACC/AHA). Unlike mechanical aortic valves in low-risk patients, mechanical mitral valves require bridging anticoagulation when warfarin must be interrupted. The preferred bridging agent is intravenous unfractionated heparin (UFH) in the inpatient setting, particularly for high-risk valves, because UFH can be rapidly reversed with protamine and has more predictable pharmacokinetics in the perioperative period. LMWH is an alternative but is less preferred for mechanical mitral valves given limited data and inability to rapidly reverse. Continuing full anticoagulation through surgery increases bleeding risk and is inappropriate for most elective surgeries.

Question 2

A 58-year-old woman with rheumatic mitral stenosis presents with progressive dyspnea. Echocardiography shows a mitral valve area of 1.3 cm², mean gradient of 7 mmHg, and a Wilkins score of 6. She has mild mitral regurgitation and no left atrial thrombus on TEE. Which intervention is most appropriate?

Accepted Answer

Percutaneous mitral balloon commissurotomy (PMBC)

Answer

PMBC is indicated for symptomatic severe mitral stenosis (MVA ≤1.5 cm²) when valve morphology is favorable (Wilkins score ≤8), there is no significant MR (mild is acceptable), and no left atrial thrombus. This patient meets all criteria. A Wilkins score of 6 indicates excellent valve pliability, with expected good procedural outcomes. Surgical options are reserved for patients with unfavorable anatomy (Wilkins >8), significant MR (≥moderate), or left atrial thrombus.

Question 3

A 72-year-old man with low-flow, low-gradient severe aortic stenosis (AVA 0.7 cm², mean gradient 28 mmHg, LVEF 30%) undergoes dobutamine stress echocardiography. At peak dobutamine dose, AVA increases to 0.9 cm² and mean gradient rises to 35 mmHg. What is the most accurate interpretation?

Accepted Answer

Pseudo-severe aortic stenosis — the valve is not truly severe

Answer

In low-flow, low-gradient AS, dobutamine stress echo differentiates true severe from pseudo-severe stenosis. When the AVA increases to >1.0 cm² with dobutamine, this indicates pseudo-severe stenosis — the low resting AVA is due to incomplete leaflet opening from low forward flow, not fixed severe stenosis. Here the AVA increased to 0.9 cm², which approaches but does not reach 1.0 cm²; however, the pattern of AVA increase with gradient increase (not a proportionally greater gradient increase) supports pseudo-severe AS. True severe AS with contractile reserve shows a fixed AVA (<1.0 cm²) despite increasing flow with a significant gradient rise.

Question 4

A 45-year-old asymptomatic man is found to have severe aortic regurgitation on routine echocardiography. LVEF is 58%, LV end-systolic dimension is 48 mm, and LV end-diastolic dimension is 72 mm. He exercises regularly without symptoms. What is the most appropriate next step?

Accepted Answer

Aortic valve replacement based on LV end-systolic dimension threshold

Answer

According to ACC/AHA guidelines, aortic valve replacement is indicated in asymptomatic severe AR when LVEF falls below 55% OR when LV end-systolic dimension (LVESD) exceeds 50 mm (Class I). This patient's LVESD is 48 mm — just below the threshold — and LVEF is 58%. However, a LVESD of 50 mm is the cutoff; at 48 mm, surgery is not yet mandated. Importantly, LVESD ≥50 mm is the key threshold, not LVEDD. The LVEDD of 72 mm alone is not a Class I surgical indication (threshold would be >65 mm as a lower-evidence indicator). Close follow-up every 6–12 months is appropriate here.

Question 5

A 68-year-old woman with hypertrophic obstructive cardiomyopathy (HOCM) and a resting LVOT gradient of 55 mmHg presents with NYHA class III dyspnea despite maximally tolerated metoprolol and disopyramide. She has a septal thickness of 22 mm and no coronary artery disease. Echocardiography reveals a suitable septal perforator anatomy. Which intervention is preferred?

Accepted Answer

Alcohol septal ablation

Answer

Both surgical septal myectomy and alcohol septal ablation (ASA) are guideline-endorsed for drug-refractory HOCM with severe obstruction. Myectomy is generally preferred in younger patients or those with complex anatomy requiring concurrent repair. ASA is preferred in older patients or those with significant comorbidities who are high surgical risk, and when septal perforator anatomy is suitable. This 68-year-old patient with suitable anatomy and no need for concomitant surgery is an appropriate ASA candidate. ICD addresses sudden death risk but does not relieve obstruction. Mavacamten is a newer option but is reserved for patients before considering invasive septal reduction.

ITE - Internal Medicine In-Training Exam Practice Test

ITE - Internal Medicine In-Training Exam Practice Test

ITE Valvular Heart Disease Management 6