Persistent Shortness of Breath Following Bioprosthetic Valve-in-Valve TAVR
An 80-year-old woman presented to her cardiologist with several months of progressive shortness of breath and chest pressure. Her medical history was notable for coronary artery disease and aortic insufficiency with 3-vessel coronary artery bypass surgery and aortic valve replacement with a 23 mm bioprosthetic valve 10 years ago. At the time, she experiences moderate chest pressure and shortness of breath with light housework that is relieved with rest. On physical examination, she was an overweight woman in no acute distress. Her blood pressure and heart rate were 128/80 mmHg and 72, respectively. On cardiac examination, she had a normal S1, single S2, and late peaking systolic ejection murmur loudest at the upper right sternal border. Her electrocardiogram demonstrated sinus rhythm with right bundle branch block. There were no acute ischemic changes. Laboratory data were notable for troponin I of 0.05 and B-type natriuretic peptide level of 2,300. A transthoracic echocardiogram (TTE) demonstrated a highly calcified bioprosthetic aortic valve with a peak velocity of 4.3 m/s, mean gradient of 39 mmHg, dimensional valve index (DVI) of 0.24, acceleration time of 120 ms, and an effective orifice area index (EOAI) of 0.5 cm2/m2 (Figure 1, panels A-B). Coronary angiography was performed and revealed 3-vessel coronary artery disease with patent grafts. Cardiac surgery was consulted for prosthetic aortic stenosis and felt the patient was high risk for repeat surgical aortic valve replacement. She subsequently underwent uncomplicated transcatheter aortic valve replacement (TAVR) with deployment of a 23 mm Medtronic CoreValve Evolut R (Medtronic, Inc.; Minneapolis, MN).
At her 2-week follow-up visit, the patient complained of persistent dyspnea and mild chest pressure with exertion. Her examination revealed clear lung fields, normal S1 and S2, with a mid-peaking systolic ejection murmur at the left sternal border without a diastolic component. TTE day 2 after valve deployment and day of follow-up visit demonstrated a well-positioned CoreValve Evolut R within the prior bioprosthetic valve with free movement of the prosthetic cusps. Doppler examination at 2 weeks revealed a peak velocity across the prosthesis of 4.3 m/s, mean gradient of 37 mmHg, DVI of 0.26, acceleration time of 80 ms, and an EOAI of 0.5 cm2/m2 (Figure 1, panels C-D). These values were similar to those obtained 2 days after TAVR.
What is the cause for the persistently elevated gradient on TTE?