Cath Lab Digest

Introduction

Transcatheter aortic valve replacement (TAVR) has become a viable alternative to traditional open heart surgery in individuals who have severe aortic valve stenosis and are of high or prohibitive surgical risk.¹ Since U.S. Food and Drug Administration (FDA) approval for the TAVR procedure in this subset, many institutions across the nation have started to perform the TAVR procedure in patients with severe native aortic valve stenosis who previously had no mechanical options for the treatment of their disease.

The use of TAVR as a valve-in-valve procedure for treating diseased bioprosthetic aortic valves has been described in the literature.^2,3 Even though it is considered off label, the minimally invasive nature of TAVR coupled with the sicker patient subset being encountered in daily practice has the potential to make the valve-in-valve procedure a very attractive treatment modality for those with progressive disease in previously placed biprosthetic valves who are too high risk for re-do surgeries. We present a representative case below.

Case presentation

The patient is an 88-year-old female who had previous aortic valve replacement (AVR) and coronary artery bypass graft surgery in 2003. At that time, she underwent three-vessel bypass (with an internal mammary to the left anterior descending, a vein graft to the obtuse marginal system, and a vein graft to the right posterior descending artery), and had AVR with a 21-mm Perimount bioprosthesis (Baxter Healthcare, now Edwards Lifesciences). Over the last year, she had developed progressive dyspnea. Echocardiograms performed over this time period revealed preserved left ventricular (LV) function with deterioration of her aortic bioprosthesis. Her bioprosthetic valve had developed progressive restenosis and had also started to develop a moderate amount of aortic insufficiency. 

The patient also has a history of oxygen-dependent chronic obstructive pulmonary disease, hypertension, and previous pacemaker implantation due to sick sinus syndrome. Her calculated risk of mortality for a re-do sternotomy and AVR was estimated at about 22%, and due to her high risk of mortality and her frailty, she was felt to be a poor candidate for a repeat open heart surgery.
Recently, she was admitted to our local hospital with a syncopal event. Her functional status also had declined to a New York Heart Association functional class III status at baseline. Her echocardiogram revealed deterioration in LV function, with an ejection fraction of about 35-40%, and she also was found to have a modest amount of mitral regurgitation in addition to her severely diseased aortic valve bioprosthesis (Figures 1-2). Coronary angiography was performed, and her bypasses were seen to be patent, with no evidence of progressive disease elsewhere. 

Due to progressive deterioration in her quality of life, the patient wanted to see if any treatment options were possible. Factors that made her treatment complicated were the progressive decline in LV function, and the uncertainty about how much functional benefit she would derive from replacing her aortic valve, now given the fact that her symptoms may be attributable to her modest mitral regurgitation. There also was uncertainty regarding how much regression of mitral regurgitation we would see if we were to consider replacing her aortic valve. Clearly, the patient was felt to be too high risk for a surgical AVR with the possibility of a mitral valve replacement as well. From a percutaneous standpoint, her peripheral anatomy was challenging, as both external iliac arterial systems demonstrated modest calcification with maximal diameters of about 7.5 millimeters (mm) by intravascular ultrasound analysis. 

After discussions with the patient and her family, we decided to proceed with an attempt at TAVR. Our hope was that replacing her diseased aortic valve would eliminate the outflow obstruction, and would also eliminate her aortic regurgitation. By doing such, we were hoping to see some mitigation in her LV dilatation, which may, in effect, decrease her mitral regurgitation.⁴