Case presentation

An 84-year-old woman, with a history of a heart murmur for more than 15 years, presented with congestive heart failure and severe mitral regurgitation. She had undergone a diagnostic catheterization 5 years earlier for dyspnea, which found moderate (2+) mitral regurgitation and a mild global reduction in left ventricular function (ejection fraction 50%), with normal coronary arteries. Diagnosed with a nonischemic cardiomyopathy, she was treated medically and did well until 1 year prior to this presentation.

She now reports progressive and severe shortness of breath with exertion, limiting her ability to perform all her usual activities. An echocardiogram found severe mitral regurgitation and deterioration in left ventricular function (ejection fraction 35% to 40%). The mechanism of her mitral regurgitation appeared to be from tethered leaflets. She was referred to a cardiac surgeon for consideration of mitral valve replacement. After her consultation, she initially declined surgery, but then developed overt congestive heart failure requiring hospital admission. At this point, she agreed to participate in a randomized controlled trial comparing mitral valve surgery to percutaneous repair of the mitral valve using a MitraClip (EVEREST II trial) and was randomized to the MitraClip arm of the trial.

Her past medical history is notable for diabetes, asthma, paroxysmal atrial fibrillation, and hypertension, and she was treated with lisinopril, furosemide, amiodarone, and warfarin. On physical examination, she appeared markedly younger than her stated age. Blood pressure measured 124/58 mmHg, heart rate was 80 and regular, and jugular venous pressure was normal. On cardiac exam, the first sound was inaudible and the second sound was loud, consistent with pulmonary hypertension. A long, 3/6 holosystolic murmur was present at the apex. A 12-lead electrocardiogram demonstrated sinus rhythm with left anterior fascicular block, an intraventricular conduction delay, and left ventricular hypertrophy. Routine blood analysis revealed mild renal insufficiency with a creatinine of 1.7 mg/dL.

Cardiac catheterization

The procedure was performed under general anesthesia and was guided by transesophageal echocardiography. Vascular access initially consisted of an 8 French sheath in the right femoral vein, and a 6 French sheath in the left femoral artery. Baseline hemodynamics were assessed and found a pulmonary artery pressure of 56/40 mmHg, a mean pulmonary capillary wedge pressure of 40 mmHg, and a cardiac output of 4.0 L/minute. A transseptal catheterization was performed and mean left atrial pressure measured 35 mmHg.

Following transseptal puncture, she received 4000 U of unfractionated heparin and maintained an activated clotting time (ACT) over 250 seconds. The transseptal sheath was exchanged for a 24 French MitraClip steerable guide. Through this guide, the MitraClip was advanced through the left atrium and oriented to the mitral valve using transesophageal echo guidance. Once the device was in the left ventricle, the clip was opened (Figure 57-1 and Video 57-1). Careful adjustments were made using echo guidance in order to position the clip at the site of maximum regurgitation. The device was gently pulled back and the leaflets were grabbed (Videos 57-2, 57-3). After the leaflets were grabbed and the clip closed (Figures 57-2, 57-3), the degree of mitral regurgitation was assessed and found to be satisfactorily reduced (Video 57-4). At this point, the clip was released. There was only minimal, 1+ residual regurgitation. Hemodynamics were reassessed. There was no diastolic pressure gradient between the left atrium and left ventricle (Figure 57-4