Valvular Heart Diseases

VALVULAR HEART DISEASES

VALVULAR HEART DISEASES

Valvular heart diseases are characterized by damage to or defects in one or more of the four heart valves: aortic, mitral, tricuspid and pulmonary valves. Normal and functioning valves ensure proper blood flow, but valvular heart diseases cause the valves to become too narrow and hardened (aortic stenosis) to open fully, or unable to close completely (aortic regurgitation). Aortic stenosis is a common heart valve disease in China. Rheumatic diseases are a major cause of aortic stenosis for Chinese patients. Due to improving living standards and the aging population, the degenerative change in valves is becoming another main cause of heart valve diseases in Chinese patients.

 

 

Currently, procedures to treat valvular heart diseases are generally divided into three categories: traditional thoracotomy heart valve replacement and repair surgery, minimally invasive valve surgery, and transcatheter valve therapy. The transcatheter valve therapy method is expected to be the key direction for the development of valvular heart disease treatment globally.

TaurusElite™

TaurusElite™ Transcatheter Aortic Valve System
(product candidate, currently in the clinical trial stage before the Listing Date)

TaurusOne®

TaurusOne® Transcatheter Aortic Valve System
(product candidate, currently in the clinical trial stage before the Listing Date)

TAVR

TAVR Overview

With the first treatment performed in France in 2002, TAVR is a globally advanced cardiovascular interventional technique by implanting a prosthetic valve through a vascular path to treat aortic stenosis. Unlike traditional thoracotomy, TAVR does not require complex tracheal intubation and extracorporeal procedures, and has the advantages of smaller trauma to patients and shorter postoperative recovery periods.

 

TAVR procedures are suitable for patients with inoperable aortic stenosis, and severe aortic stenosis patients with high surgical risk who cannot withstand the traditional open-heart surgery. TAVR procedures are also increasingly being performed on intermediate to low surgical risk patients. In August 2019, in the U.S., the FDA expanded the indications of TAVR to cover patients with low surgical risk, which account for 79.9% of all SAVR operable patients.

Aortic Stenosis

Aortic Stenosis Overview

Aortic stenosis is the narrowing of the aortic valve opening. Aortic stenosis restricts the blood flow from the left ventricle to the ascending aorta during systole. CAS and BAV are two main characteristics of aortic stenosis patients in China.

 

CAS is a progressive calcification of leaflets. Calcification happens when calcium deposits form on a patient’s aortic valve, causing the opening of the aortic valve to narrow. This narrowing can become severe enough to reduce blood flow through the aortic valve. Due to shear stress, inflammation, lipid infiltration and myofibroblast differentiation, leaflet calcification worsens in patients, leading to progressive aortic stenosis, and eventually the patient’s valve becomes obstructed, requiring valve replacement.

 

According to the second edition of Transcatheter Aortic Valve Treatment Manual, calcified aortic valve stenosis is the third most common cardiovascular disease after coronary heart disease and hypertension. BAV is a heart disease where the aorta has two leaflets (bicuspid valve) instead of the normal three leaflets, mainly causing valvular dysfunction and severe aortopathy leading to aortic stenosis. BAV is a common form of cardiac valvular disease in China. Demographic factors such as cholesterol level, genes and gender are found to relate to the prevalence of BAV.

 

Valvular aortic stenosis is a life-threatening disease which can be treated by pharmacological approach, surgical procedures or interventional procedures. The pharmacological approach can only help alleviate the patients’ symptoms, but cannot prevent aortic stenosis from progressing to severe aortic stenosis. If severe aortic stenosis is not treated by replacing heart valves through surgeries or interventional procedures, patients will experience worsening symptoms, which can lead to death. Among surgeries, balloon valvotomy is used primarily in children and very young adults with congenital aortic stenosis, and SAVR, the traditional open-heart surgery, is a common choice for patients younger than 75 years old and for patients with low surgical risk.