Mitral and Tricuspid Regurgitation

Addressing a Significant Unmet Clinical Need

Mitral and tricuspid regurgitation, are conditions which lead to poor quality of life, cardiac decompensation and early death, and affect over 4 million people in the US alone. Millipede’s IRIS annuloplasty ring system has been developed to meet the growing challenges of treating these patients.

Figure 1

Source: Stuge O and Liddicoat J: Emerging Opportunities for Cardiac Surgeons within Structural Heart Disease, J Thorac and CardiovascSurgery: 132:1258-1261 (2006)

Mitral Valve Regurgitation - A Complex Problem with Multiple Presentations

Mitral valve disease presents itself in primarily two forms: primary or degenerative mitral regurgitation (DMR) is when the valve itself is damaged or malformed, and secondary or functional mitral regurgitation (FMR) in which the valve is normal but the diseased or enlarged left ventricle impedes normal valve function. The majority of patients who are diagnosed with mitral valve disease have FMR (~75%) versus patients with DMR (~25%)1.

Symptoms can be difficult for patients to identify but may include heart palpitations, fatigue and shortness of breath. Left untreated, mitral regurgitation has serious consequences, often associated with chronic volume overload, left ventricular enlargement, atrial fibrillation and symptoms of congestive heart failure (CHF). However, due to the complex nature and position of the mitral valve, surgical intervention is complex. Of patients treated surgically, 85% have DMR and only 15% have FMR2. DMR patients have seen very positive surgical outcomes: a repair rate of 95%. On the other hand, for FMR patients, who are often elderly or suffer from multiple co-morbidities, surgical outcomes are low – a survival rate of only 27% – and thus open heart surgical intervention is rarely undergone3.

Significant Opportunity for FMR Treatment

Mild mitral regurgitation in patients with FMR may be controlled with the use of anticoagulants, digitalis, diuretics, and vasodilators. However, it often isn’t until left ventricular enlargement or insufficiency is significant that symptoms present. Historically, the only surgical repair intervention available has been open heart surgery – but with the left ventricle already compromised and frequent co-morbidities, many patients do not qualify as good surgical candidates. Less than 2% of those with FMR undergo surgical treatment.

New Options with Transcatheter Approach

Transcatheter approaches to valve disease are preferable – primarily because of the ability to avoid the invasiveness of open heart surgery and cardiopulmonary bypass. Transcatheter aortic valve replacement (TAVR) was the first move into transcatheter valve therapy space. While the mitral valve is more complex, the success of TAVR has opened the doorway for a transcatheter approach to the mitral valve – and the mitral valve repair and replacement market looks to be up to three times the size of TAVR4.

Market Opportunity

According to BMO Capital Markets analysis, there are an estimated 4.1 million mitral regurgitation patients the United States – and approximately 1.67 million are eligible for treatment. Conventional wisdom suggests the volume is similar in Europe. Of those 1.67 million, only an estimated 30,000 are currently treated with surgical intervention. When one factors in the high incidence and low-treatability of FMR, and considers the potential European market as well, the potential for a transcatheter MR intervention becomes very exciting.

Figure 1

Source: EuroIntervention 2014; 9: 1133-113

Tricuspid Valve Repair – Additional Unmet Clinical Need

Tricuspid valve regurgitation is the leakage of blood from the right ventricle back to the right atrium, often caused by enlargement of the right ventricle. This enlargement can be due to heart failure, pulmonary hypertension, cardiomyopathy or congenital defects. Symptoms, including fatigue and shortness of breath, are often overlooked or associated with underlying health problems, causing a vast majority of patients, including many considered high risk, to go untreated. Left undiagnosed and untreated, if tricuspid valve regurgitation becomes severe, it can cause serious health complications, especially when combined with comorbidities. Nearly 50 percent of patients with mitral valve regurgitation also have tricuspid regurgitation5.

The market opportunity in the US for tricuspid valve repair is smaller than the mitral valve market, but not insignificant; with 1.4 million patients with functional tricuspid valve disease and 400,000 who suffer from degenerative tricuspid valve regurgitation6.

For detailed market analysis see our News page.

Reproducing the Gold Standard in Valve Repair

Semi-Rigid Annuloplasty Rings Provide Most Durable Solution

The gold standard in surgical heart valve repair today is a complete annuloplasty ring. The ring reduces the valve annulus enabling the leaflets to return to coaptation and reducing mitral regurgitation. Since the inception of mitral valve annuloplasty over 40 years ago by Professor Alain Carpentier, numerous annuloplasty rings and bands have been developed.

In the meta-analysis led by Julien Magne, [fig 1] reviewing mitral valve repairs with annuloplasty rings versus bands, and flexible versus semi-rigid and rigid material, the data clearly found that semi-rigid complete annuloplasty rings provided the most durable solution. Millipede leverages this optimal combination in the design of the IRIS.

Figure 1

Figure 1 | Source: Magne et al., Cardiology 2009; 112: 244-259

1 Wuensch, Joanne, BMO Capital Markets, A Toolbox Will Be Needed to Treat Mitral Valve Disease: Repair and Replacement, January 4, 2017
2 Wuensch, Joanne, BMO Capital Markets, A Toolbox Will Be Needed to Treat Mitral Valve Disease: Repair and Replacement, January 4, 2017
3 Wuensch, Joanne, BMO Capital Markets, TMVR, It’s Gonna Be Big, September 11, 2015
4 Blair, Jenny, Pharma & Medtech Business Intelligence, Transcatheter Mitral Valve Therapy, December 15, 2015
5 Argarwal et al., Interventional Card Perspective on Functional TR, Circ Cardiovasc Interv 2009
6 Rogers J., The Tricuspid Valve, Circulation, 2009