First-in-Human Implantations of the NaviGate Bioprosthesis in a Severely Dilated Tricuspid Annulus and in a Failed Tricuspid Annuloplasty Ring
Based on an old misconception that the tricuspid valve is not important for cardiac performance, functional tricuspid regurgitation (TR) has been historically ignored. As a consequence, an increasing number of patients present in the current era with severe TR associated with right heart failure that is refractory to medical treatment. Traditional or redotricuspid valve surgery in that setting has been shown to have high mortality (up to 35% at 30 days).1–3 Thereby, transcatheter valve implantation technology seems as an attractive alternative. Herein, we report the first-in-human successful implantation of the NaviGate valved-stent (NaviGate Cardiac Structures, Inc, NCSI, Lake Forest, CA) in 2 patients with severe TR and prohibitive risk for conventional surgery, for which they received Food and Drug Administration and institutional review board approvals for compassionate use (Figure 1).
A 64-year-old woman presented after multiple admissions for refractory right heart failure with severe functional TR secondary to annular dilatation, severe right ventricular (RV) dysfunction, severe pulmonary hypertension (systolic pressure, 75 mm Hg), and moderate ischemic mitral regurgitation (Figure 2A). Other comorbidities included chronic kidney dysfunction, chest radiation for breast cancer, atrial fibrillation, obstructive lung disease, and coronary bypass surgery with patent grafts. The patient was deemed high risk for conventional open-heart surgery by the Multidisciplinary Heart Team and was found a candidate for compassionate use of a first-in-human NaviGate valved-stent implantation. Preoperative sizing included a focused 4-dimensional computed tomography that was used to develop a 3-dimensional printing model of the right heart structures to simulate the implantation steps of the NaviGate device (Figure 3A–3C). The tricuspid annulus (TA) measured 50×40 mm on the computed tomographic scan.
The patient underwent the implantation procedure in a hybrid operating room under fluoroscopy, transesophageal, and intracardiac echocardiographic guidance. We used intracardiac echocardiography to ensure coaxial alignment of the valved-stent to the TA plane before deployment. Transatrial access was obtained via anterolateral mini-thoracotomy using Seldinger technique, and then the delivery system mounted with the valved stent was advanced to the center of the TA. The NaviGate valved-stent (48 mm) was deployed on beating heart without rapid ventricle pacing (Figure 4). Intraoperative transesophageal chocardiography showed functioning bioprosthesis with interval improvement of severe TR to moderate paravalvular leak at the level of the septal leaflet (Figure 5).
The patient was extubated on postoperative day (POD#) 8, transferred to a ward on POD#17, and discharged home on POD#29. A predischarge echocardiogram showed moderate to severe RV dysfunction and mild to moderate paravalvular TR. She had functional improvement at 5 months; however, she was admitted to the hospital 6 months after surgery for ischemic colitis (unrelated to the procedure) and underwent right hemicolectomy complicated by sepsis and subsequently died.
A 78-year-old man presented with progressive congestive heart failure refractory to optimal medical therapy. He has a history of 3 open-heart surgeries for coronary bypass (patent grafts), mitral valve repair with annuloplasty ring, and 2 tricuspid valve repairs (annuloplasty ring 34 mm). An echocardiogram showed left ventricular ejection fraction 45%, severe pulmonary hypertension (systolic pressure 90 mm Hg), severe RV dysfunction, severe TR because of leaflets tethering, and mild functional mitral regurgitation (Figure 2B). Other comorbidities included diabetes mellitus, atrial fibrillation, obstructive lung disease, and chronic kidney disease. The patient was deemed high risk for conventional open-heart surgery by the Multidisciplinary Heart Team and was found as a candidate for compassionate use of catheter-delivered NaviGate valved-stent. Preoperative planning included testing in a 3-dimensional printing model (Figure 3D–3F).
Percutaneous transjugular access was obtained with placement of 42F introducer sheath. The NaviGate valved-stent (36 mm) was positioned at the center of the tricuspid annuloplasty ring and then deployed in a controlled release fashion on beating heart (Figure 6A and 6B). The vascular access was secured with a Perclose device, and then skin incision was closed (Figure 6C). Intraoperative transesophageal chocardiography showed interval improvement of severe TR to mild paravalvular leak (Figure 7). The patient was extubated on the day of surgery, transferred to the ward on POD#2, and was discharged home on POD#7 after an uneventful postoperative course. Predischarge echocardiogram showed severe RV dysfunction and mild paravalvular TR. He is 3 months out from the procedure with functional improvement, stable mild paravalvular TR, and interval improvement of RV function on a follow-up echocardiogram.
The Heart Team at our institution applies the following criteria to identify candidates for transcatheter tricuspid valve implantation: severe symptomatic TR, prohibitive surgical risk (multiple comorbidities, complicated reoperation, severe RV dysfunction), pulmonary artery pressure ≤90 mm Hg (by echocardiography and right heart catheterization), and the appropriate TA or ring size assessed on focused 4-dimensional computed tomographic scan (available NaviGate valved-stent sizes: 36, 40, 44, 48, and 52 mm). The successful implantation of the NaviGate valved-stent in both patients resulted in interval improvement of the degree of TR, however with residual paravalvular leak. Achieving a complete seal was more challenging in the first patient with severely dilated native TA compared with the second patient with the annuoplasty ring. Another technical challenge is the long angulation part of the current delivery system which limited a perfect coaxial alignment of the valved-stent in the TA. Modifications are being currently ongoing to shorten the distal angulation part of the delivery system. We prefer to oversize the device by 5% to 10% to the TA or the prior ring size to achieve better sealing. Neither of the 2 patients had conduction disturbances or coronary obstruction after the procedure (Figure 8). We use computed tomographic scan to examine the vascular anatomy before surgery, and we do not use venous access with diameter <15 mm. Anticoagulation regimen for the Navigate valved-stent is aspirin and warfarin.
The short-term results suggest that the procedure is safe and feasible using transatrial or transjugular approaches on beating heart. Significant reduction of the degree of TR could help improve the clinical status with concurrent medical therapy. Further developments in the current technology will help to achieve optimal results.
Dr Navia is the inventor on patents related to this device and is a consultant to the company. The other authors report no conflicts.
- © 2017 American Heart Association, Inc.