First MitraClip NT Case in South Florida

Valvular heart disease exacts a significant burden on the U.S. population, affecting approximately 4 million people.^1,2,3 Chronic mitral regurgitation (MR) is the most common type of valve lesion and its prevalence increases considerably with advancing age.^2,3 Moderate or severe MR occurs at a frequency of 1.7%, adjusted to the U.S. adult population in 2000, increasing from 0.5 to 9.3% between 18 and ≥75 years of age, respectively.^1,2 If left untreated, the disease often progresses, causing negative remodeling of the left ventricle, ultimately leading to heart failure. Historically, the management of this condition had been surgical repair or replacement. In the last decade, percutaneous repair using the MitraClip device (Abbott Vascular) has emerged as a less invasive alternative. Scientific studies like EVEREST I, EVEREST II, ACCESS-Europe, and REALISM have demonstrated this approach to be safe and effective. The scientific evidence collected in these studies led to MitraClip’s approval by CE Mark in 2008 for both primary and secondary MR, and by the FDA in October of 2013 for primary MR patients with prohibitive surgical risk.³ Among the reported complications related to the procedure are the need for blood transfusion, access site bleeding, transseptal puncture-related complications, device embolism, and single leaflet device attachment (SLDA). Device embolization is very rare.³ In the EVEREST II study, all SLDA cases later required surgery.^3,4 In 2016, Abbott Vascular introduced a newer generation device, the MitraClip NT, which provides improvements in grasping, steering, and retraction when compared to the first-generation MitraClip device.^5,6,7 Here we present a case of severe degenerative MR with complex anatomy that was initially treated using the first-generation MitraClip device, resulting in an SLDA of the second MitraClip. The patient later returned for successful treatment using the MitraClip NT device, marking the first commercial use of this product in South Florida.

Case

Our patient is a 49-year-old woman with a history of a large anterior ST elevation myocardial infarction, treated with PCI of the LAD. The patient had a delayed presentation resulting (despite primary PCI) in a severe cardiomyopathy with subsequent implantable cardioverter defibrillator (ICD) implantation. She had New York Heart Association class III symptoms despite optimal medical therapy and was hospitalized several times for congestive heart failure (CHF) decompensation. Echocardiography revealed an ejection fraction of 20% with anterior wall akinesis, severe mitral regurgitation, and increased pulmonary pressures. Her mitral regurgitation was eccentric, suggesting leaflet pathology, and likely a mixed picture of degenerative and functional MR. This was confirmed on transesophageal echocardiography (TEE), which demonstrated severe mitral regurgitation with a posteriorly directed jet and prolapse of the anterior mitral valve leaflet A2 scallop (Figure 1A-B). A nuclear SPECT stress test revealed a fixed defect in the anterior wall consistent with scar. Coronary angiography and hemodynamic evaluation confirmed a chronic total occlusion (CTO) of the proximal left anterior descending (LAD) stent with faint collaterals from a non-dominant right coronary artery (RCA), and type 2 pulmonary hypertension (HTN) with a pulmonary capillary wedge pressure (PCWP) of 40 mm Hg (Figure 2A-B). She was considered a prohibitive risk for surgical mitral valve repair and was therefore referred for percutaneous mitral valve repair using the MitraClip device in order to improve her symptoms. 

First Procedure. The patient underwent a sterile surgical prep and general anesthesia. TEE guidance was used throughout the procedure. Primary vascular access was via the right common femoral vein, which was preclosed using 2 Perclose ProGlide devices (Abbott Vascular) in the usual manner, and a temporary 8 French (Fr), 11 cm sheath was placed in the vein. A radiofrequency NRG Transseptal Needle (Baylis Medical) and sheath were used for transseptal puncture, after which the patient received unfractionated heparin at a dose of 80 units/kg, maintaining the activated clotting time (ACT) greater than 250 seconds throughout the procedure. The femoral vein was then dilated and a 24 Fr MitraClip guide catheter was advanced over a dilator into the left atrium.

The MitraClip device was prepared outside the body in the usual manner and then inserted through the guide catheter into the left atrium. Using standard techniques, the device was manipulated into position and deployed, reducing the MR from 4+ to 2+. A decision was then made to place a second MitraClip once the transvalvular gradient was confirmed by TEE as 1 mm Hg. The second clip was prepared outside the body in the usual manner, and then advanced through the guiding catheter in a similar fashion and manipulated down to the level of the mitral valve. Multiple TEE views confirmed that both the anterior and posterior leaflets were grasped by the device. Three-dimensional (3D) imaging confirmed an adequate tissue bridge in the short axis “surgeon’s view.”  The second clip was medial relative to the first clip, still in an A2-P2 position. Prior to deploying the clip, the MR was noted to be 1+ and the transvalvular gradient was 2 mm Hg. The clip was released, but almost immediately noted to have an SLDA. No embolization occurred.  

A third clip was prepared with the intention of “stabilizing” the SLDA between the first and third clips. After multiple attempts, anterior and posterior leaflet grasp medial to the SLDA could not be confirmed. The position of the third clip was now close to the A1-P1 segment and the posterior leaflet length was short. Further attempts were aborted in order to avoid another SLDA or embolization. Hemostasis was obtained using the ProGlide devices and manual compression. The patient’s hospital course was uncomplicated and she was discharged the following day (Figure 3A-H, Figure 4A-D).

The patient continued to have episodes of heart failure and volume overload refractory to medical treatment. After reviewing her case, it was felt that the MitraClip NT device would provide for a better grasp of the short medial aspect of the P2 scallop, allowing us to stabilize the SLDA and reduce the mitral regurgitation. She was readmitted for her second procedure.

Second Procedure. Once again, the patient underwent a sterile surgical prep and general anesthesia. TEE guidance was used throughout the procedure. Primary vascular access was via the right common femoral vein that was preclosed using 2 ProGlide devices in the usual manner and a temporary 8 Fr, 11 cm sheath was placed in the vein. A floppy J-tipped wire successfully crossed the residual small atrial septal defect (ASD) from the previous procedure, after which the patient received unfractionated heparin at a dose of 80 units/kg, maintaining the ACT greater than 250 seconds throughout the procedure. The femoral vein was dilated and a 24 Fr MitraClip guide catheter was advanced over a dilator into the left atrium.

The MitraClip NT device was prepared outside the body in the usual manner and then inserted through the guide catheter into the left atrium. Using standard techniques and multiple intraprocedural adjustments, the device was manipulated into position and deployed just medial to the SLDA device, reducing the regurgitation (which had worsened since the last procedure) from 4+ to 2+. Most importantly, the SLDA was completely stabilized, markedly reducing the risk of device embolization. The transvalvular gradient remained at 2 mm Hg. There was a double orifice noted on 3D TEE. After deployment, all 3 clips remained in stable position and the mitral gradient remained normal with 2+ MR (Figure 5A-F, Figure 6A-B).

Discussion 

Edge-to-edge percutaneous mitral repair is the most advanced and safe alternative to surgical therapy for DMR in the United States.³ However, the complexity and anatomic variability of the mitral valve apparatus can lead to challenging and complex procedures. In this case, the posterior mitral leaflet was very short, making it difficult to grasp with the first-generation MitraClip device and leading to an SLDA during the index procedure. The second procedure was the first in South Florida using the MitraClip NT device, resulting in a good outcome for the patient. The MitraClip NT has several advantages over its predecessor. Its “grippers” are made of nitinol, providing greater elasticity and allowing for a larger gripper drop angle.^5,6,7 This permits better leaflet engagement and capture. Also, it has enhanced steering, which allows for more precise torque translation and clip placement.^5,6,7 These two characteristics make it more suitable for challenging cases such as the one described here. Using the MitraClip NT device, we were able to both effectively reduce the MR and stabilize the SLDA that occurred during the first procedure.

Our patient’s complex anatomy highlights one of the potential future uses of the MitraClip NT device. The MitraClip is approved only for degenerative MR and not for functional mitral regurgitation (FMR). The ongoing COAPT trial is the first randomized, controlled trial to evaluate the potential benefit of MitraClip therapy compared to standard medical therapy in high-risk patients with heart failure and FMR.³ This trial will help to shed light on the question of whether or not percutaneous mitral valve repair should be considered for severe FMR, a patient subset previously known to derive limited benefit from surgical repair or replacement. Continued use of the device both commercially and in clinical trials will help to mold understanding of this complex disease and the mitral valvular apparatus, hopefully clarifying the group(s) of patients whose morbidity and mortality can be favorably impacted in the future.

In the future, patients may have access to a percutaneous mitral prosthesis.¹⁰

Conclusion 

In high-risk surgical patients, edge-to-edge percutaneous mitral repair utilizing the MitraClip device is a safe and effective alternative to surgical treatment for chronic symptomatic severe degenerative MR. In our limited experience, we favor the second-generation MitraClip NT device over the first-generation MitraClip in cases with challenging mitral leaflet morphology.

References

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2. Nkomo VT, Gardin JM, Skelton TN, Gottdiener JS, Scott CG, Enriquez-Sarano M. Burden of valvular heart diseases: a population-based study. Lancet. 2006; 368(9540): 1005-1011.
3. Suradi HS, Kavinsky CJ, Hijazi ZM. Percutaneous mitral valve repair: the MitraClip device. Global Cardiology Science and Practice. 2016:2016(2). Available online at https://dx.doi.org/10.21542/gcsp.2016.17. Accessed February 19, 2017.
4. Glower DD, Kar S, Trento A, et al. Percutaneous mitral valve repair for mitral regurgitation in high risk patients: results of the EVEREST II study. J Am Coll Cardiol. Jul 15 2014; 64(2): 172-181.
5. Tests performed by and data on file at Abbott Vascular.
6. MitraClip Clip NT Delivery System Instructions for Use.
7. Robertson SW, Pelton AR, Ritchie RO. Mechanical fatigue and fracture of nitinol. International Materials Reviews. 2012; 57(1): 1-36.
8. Sorajja P, Mack M, Vemulapalli S, et al. Initial experience with commercial transcatheter mitral valve repair in the United States. J Am Coll Cardiol. 2016; 67(10): 1129-1140.
9. Ailawadi G. Updated MitraClip® Outcomes From the STS TVT Registry. Presented at the Transcatheter Cardiovascular Therapeutics conference, October 30, 2016, Washington, D.C. Available online at https://www.tctmd.com/slide/updated-mitraclip-outcomes-sts-tvt-registry. Accessed February 19, 2017.
10. Muller DW, Farivar RS, Jansz P, Bae R, Walters D, Clarke A, et al; Tendyne Global Feasibility Trial Investigators. Transcatheter mitral valve replacement for patients with symptomatic mitral regurgitation: a global feasibility trial. J Am Coll Cardiol. 2017 Jan 31; 69(4): 381-391.

Disclosures: The authors report no conflicts of interest regarding the content herein.

The authors can be contacted via Patty Vila at patricia.vila@tenethealth.com.