Between a Rock and a Hard Place
An 85-year-old Caucasian female patient presented to the emergency department with complaints of shortness of breath and "almost passing out" with exertion that has been occurring over the last couple of weeks prior to admission. She had noticed progressive fatigue and shortness of breath for a few months but within the last couple of weeks had also had two episodes of pre-syncope with the most recent spell being an hour before arrival to the emergency department. The most recent episode was witnessed by her daughter who described her as appearing pale and sweaty in addition to appearing to be struggling to catch her breath.
The patient's past medical history was remarkable for coronary artery disease with a history of having a drug-eluting stent to her left circumflex 3 years prior for typical angina chest discomfort that could not be alleviated with medical therapy. She also had a 10-year history of type II diabetes mellitus, which was complicated by Stage IV chronic kidney disease. She also had a history of permanent dual chamber pacemaker placement for complete heart block that occurred 1 year ago. There was no history of rheumatic fever or other prolonged childhood illnesses.
She was a retired teacher who was a life-long non-smoker and non-drinker.
Her home medications included aspirin 81 mg daily, calcium-carbonate and vitamin D3 supplement, carvedilol 25 mg bid, furosemide 20 mg bid, regular insulin 0-6 units subcutaneous tid with meals, lisinopril 10 mg daily, and spironolactone 25 mg daily.
On initial examination, she was afebrile with a heart rate of 62 bpm, blood pressure of 136/68 (without orthostasis), a respiratory rate of 18 breaths/min with an oxygen saturation of 98% on 2 liters via nasal cannula. She was alert and oriented times 3. Her jugular venous pressure was 9 cm, and she had normal carotid upstrokes without bruits. Her lungs were clear to auscultation and percussion. Her cardiac point of maximal impulse was enlarged but non-displaced. There was a normal S1 and S2, a II/VI blowing holosystolic murmur at the left lower sternal border and apex, but there was no diastolic murmur appreciated. There were no gallops, clicks, or thrills noted. The remainder of her exam was unremarkable with the exception that her pedal pulses were reduced (1+ bilaterally).
The patient was admitted and ruled out for myocardial ischemia with serial troponins. The electrocardiogram revealed normal sinus rhythm with bi-atrial enlargement and left ventricular hypertrophy. A 2-view chest x-ray revealed mildly increased cardiac silhouette andpulmonary vascular cephalization but no alveolar infiltrates. Her creatinine was 1.6 gm/dL with a glomerular filtration rate of 17mL/min/1.73m2. Sodium level was 132 g/dL, but the electrolytes were otherwise normal. Complete blood count was normal. The following videos and image are from transthoracic echocardiography done the following day.
What is the most likely etiology of this patient's mitral valve stenosis?