Transcatheter Mitral Valve Lithotripsy as a Pretreatment to Percutaneous Balloon Mitral Valvuloplasty for Heavily Calcified Rheumatic Mitral Stenosis

Percutaneous balloon mitral valvuloplasty with shockwave lithotripsy for the treatment of calcific mitral valve stenosis

BACKGROUND

Calcific mitral stenosis (calcific MS) presents a challenge for surgical treatment and is a contraindication for most contemporary transcatheter mitral valve replacement devices (TMVR), rendering patients with very limited therapeutic options.

AIMS

This study aims to assess the clinical and hemodynamic follow-up after mitral valve lithotripsy (MVL).

METHODS

All consecutive patients who underwent MVL to treat symptomatic calcific MS at St Michael's Hospital, Toronto, Canada, were included. Patients were deemed unsuitable for mitral surgery or TMVR after heart team assessment. Patients with rheumatic MS or ≥moderate mitral regurgitation (MR) were excluded. The primary endpoint was a reduction in the invasive mitral gradient by ≥50% without significant (≥moderate) MR.

RESULTS

Fifteen patients underwent MVL between 2021 and 2023 with a mean age of 74 ± 9 years; 53% were female, with a mean STS score of 10% ± 0.1%. Following MVL, there was a reduction in the invasively measured mean trans-mitral gradient compared to baseline (14 mmHg vs. 6 mmHg; p < 0.05). The primary endpoint was achieved in 8 patients (53%) with no major procedural complications. At follow-up (median 90 days, IQR 58-115 days), 14 (93%) patients reported improved symptoms from New York Heart Association (NYHA) Class III-IV to NYHA Class I-II (p < 0.01) with stable echo-derived mean gradient (7.7 mmHg ± 2 mmHg vs. 8.4 mmHg ± 2.9 mmHg (p = 0.7).

CONCLUSIONS

In selected patients with symptomatic inoperable calcific MS, MVL was safe and associated with significant short-term clinical and hemodynamic improvement. MVL may represent a new compassionate therapy for this challenging cohort. Further studies are needed to determine the long-term outcomes and help define the role of IVL technology in treating calcific valvular conditions.

Rheumatic and Degenerative Mitral Stenosis: From an Iconic Clinical Case to the Literature Review

Mitral stenosis (MS) poses significant challenges in diagnosis and management due to its varied etiologies, such as rheumatic mitral stenosis (RMS) and degenerative mitral stenosis (DMS). While rheumatic fever-induced RMS has declined in prevalence, DMS is rising with aging populations and comorbidities. Starting from a complex clinical case of DMS, the aim of this paper is to review the literature on mitral stenosis by analyzing the available tools and the differences in terms of diagnosis and treatment for rheumatic and degenerative stenosis. Emerging transcatheter techniques, such as transcatheter mitral valve replacement (TMVR) and lithotripsy-facilitated percutaneous mitral commissurotomy (PMC), represent promising alternatives for DMS patients deemed unfit for surgery. In particular, intravascular lithotripsy (IVL) has shown potential in facilitating percutaneous interventions by fracturing calcific deposits and enabling subsequent interventions. However, larger prospective studies are warranted to validate these findings and establish IVL's role in DMS management. To further enhance this technique, research could focus on investigating the long-term outcomes and durability of mitral lithotripsy, as well as exploring its potential in combination with PMC or TMVR.

Review of intravascular lithotripsy for treating coronary, peripheral artery, and valve calcifications

Management of intracoronary calcium (ICC) continues to be a challenge for interventional cardiologists. There have been significant advances in calcium treatment devices. However, there still exists a knowledge gap regarding which devices to choose for the treatment of ICC. The purpose of this manuscript is to review the principles of intravascular lithotripsy (IVL) and clinical data. The technique of IVL will then be compared to alternative calcium treatment devices. Clinical data will be reviewed concerning the treatment of coronary, peripheral artery and valvular calcifications. Controversies to be discussed include how to incorporate IVL into your practice, what is the best approach for treating calcium subtypes, how to approach under-expanded stents, what is the ideal technique for performing IVL, how safe is IVL, whether imaging adds value when performing IVL, and how IVL fits into a treatment program for peripheral arteries and calcified valves.

Transcatheter heart valve interventions for patients with rheumatic heart disease

Rheumatic heart disease [RHD] is the most prevalent cause of valvular heart disease in the world, outstripping degenerative aortic stenosis numbers fourfold. Despite this, global resources are firmly aimed at improving the management of degenerative disease. Reasons remain complex and include lack of resources, expertise, and overall access to valve interventions in developing nations, where RHD is most prevalent. Is it time to consider less invasive alternatives to conventional valve surgery? Several anatomical and pathological differences exist between degenerative and rheumatic valves, including percutaneous valve landing zones. These are poorly documented and may require dedicated solutions when considering percutaneous intervention. Percutaneous balloon mitral valvuloplasty (PBMV) is the treatment of choice for severe mitral stenosis (MS) but is reserved for patients with suitable valve anatomy without significant mitral regurgitation (MR), the commonest lesion in RHD. Valvuloplasty also rarely offers a durable solution for patients with rheumatic aortic stenosis (AS) or aortic regurgitation (AR). MR and AR pose unique challenges to successful transcatheter valve implantation as landing zone calcification, so central in docking transcatheter aortic valves in degenerative AS, is often lacking. Surgery in young RHD patients requires mechanical prostheses for durability but morbidity and mortality from both thrombotic complications and bleeding on Warfarin remains excessively high. Also, redo surgery rates are high for progression of aortic valve disease in patients with prior mitral valve replacement (MVR). Transcatheter treatments may offer a solution to anticoagulation problems and address reoperation in patients with prior MVR or failing ventricles, but would have to be tailored to the rheumatic environment. The high prevalence of MR and AR, lack of calcification and other unique anatomical challenges remain. Improvements in tissue durability, the development of novel synthetic valve leaflet materials, dedicated delivery systems and docking stations or anchoring systems to securely land the transcatheter devices, would all require attention. We review the epidemiology of RHD and discuss anatomical differences between rheumatic valves and other pathologies with a view to transcatheter solutions. The shortcomings of current RHD management, including current transcatheter treatments, will be discussed and finally we look at future developments in the field.

Multimodality imaging for patient selection, procedural guidance, and follow-up of transcatheter interventions for structural heart disease: a consensus document of the EACVI Task Force on Interventional Cardiovascular Imaging: part 1: access routes, transcatheter aortic valve implantation, and transcatheter mitral valve interventions

Transcatheter therapies for the treatment of structural heart diseases (SHD) have expanded dramatically over the last years, thanks to the developments and improvements of devices and imaging techniques, along with the increasing expertise of operators. Imaging, in particular echocardiography, is pivotal during patient selection, procedural monitoring, and follow-up. The imaging assessment of patients undergoing transcatheter interventions places demands on imagers that differ from those of the routine evaluation of patients with SHD, and there is a need for specific expertise for those working in the cath lab. In the context of the current rapid developments and growing use of SHD therapies, this document intends to update the previous consensus document and address new advancements in interventional imaging for access routes and treatment of patients with aortic stenosis and regurgitation, and mitral stenosis and regurgitation.

Intravascular Lithotripsy for Severe RVOT Calcification to Optimize Transcatheter Pulmonary Valve Replacement

The presence of severe right ventricular outflow tract calcification may preclude safe and effective transcatheter pulmonary valve replacement in patients with pulmonary allograft stenosis owing to the risk of conduit tear and suboptimal annular expansion. Debulking calcium using intravascular lithotripsy within the right ventricular outflow tract may mitigate this risk and improve valve hemodynamics. (Level of Difficulty: Advanced.).

Lithotripsy-Assisted Transcatheter Mitral Valve Replacement for Severe Mitral Annular and Valve Calcification

Background

Transcatheter mitral valve replacement (TMVR) is evolving; however, limitations include severe calcification of the mitral valve leaflets and mitral annular calcification (MAC), which may be associated with incomplete valve expansion. Shockwave intravascular lithotripsy (IVL)-assisted percutaneous mitral valvuloplasty to treat calcific mitral stenosis has been reported. We describe the first human use of IVL-assisted transseptal TMVR with the Intrepid valve to treat a severely calcified mitral valve in a patient with severe stenosis and regurgitation.

Methods

An 83-year-old man with rheumatic heart disease and severe MAC (MAC score, 10; calcium volume score, 7756 cm3) presented with combined mitral stenosis and regurgitation (valve area, 1.5 cm2; 3+ mitral regurgitation [MR]) and medically refractory heart failure symptoms and was enrolled into the APOLLO (Transcatheter Mitral Valve Replacement With the Medtronic Intrepid TMVR System in Patients With Severe Symptomatic Mitral Regurgitation) trial of Intrepid valve TMVR. Transseptal implantation of a 48-mm Intrepid valve was facilitated by Shockwave IVL delivered via two 8.0 × 60-mm M5+ balloons placed across the mitral annulus before implantation. Cerebral embolic protection during IVL and valve implant was provided by a Sentinel device and left subclavian balloon occlusion.

Results

Despite initial postimplant valve frame deformation and moderate central MR, postdilation achieved valve frame expansion and reduced MR. Echocardiography and computed tomography performed before hospital discharge and at 30 days show progressive valve frame expansion in the anteroposterior dimension, increased valve area, and resolution of MR.

Conclusions

Intravascular lithotripsy of severe MAC before self-expanding TMVR may enhance annular compliance, mitigate fibroelastic recoil, and minimize TMVR valve frame deformation. Although promising, further study is required before IVL is considered a routine adjunct for TMVR in severe MAC.

Lithotripsy of Calcified Aortic Valve Leaflets by a Novel Ultrasound Transcatheter-Based Device

The increasing incidence of calcific aortic valve disease necessitates the elaboration of new strategies to retard the progression of the pathology with an innovative solution. While the increasing diffusion of the transcatheter aortic valve replacements (TAVRs) allows a mini-invasive approach to aortic valve substitution as an alternative to conventional surgical replacement (SAVR) in an always larger patient population, TAVR implantation still has contraindications for young patients. In addition, it is liable to undergo calcification with the consequent necessity of re-intervention with conventional valve surgery or repeated implantation in the so-called TAVR-in-TAVR procedure. Inspired by applications for non-cardiac pathologies or for vascular decalcification before stenting (i.e., coronary lithotripsy), in the present study, we show the feasibility of human valve treatment with a mini-invasive device tailored to deliver shockwaves to the calcific leaflets. We provide evidence of efficient calcium deposit ruptures in human calcified leaflets treated ex vivo and the safety of the treatment in pigs. The use of this device could be helpful to perform shockwaves valvuloplasty as an option to retard TAVR/SAVR, or as a pretreatment to facilitate prosthesis implantation and minimize the occurrence of paravalvular leak.