Heart valve biomechanics

Heart valves are dynamic structures, that are subjected to cyclical loading in each heart beat. The frequency of the loading is dependent on the heart rate, and the amplitude of loading is dependent on transmitral pressure. In a physiological range, valves seem to sustain these forces well and maintain their biological homeostasis. However, in an unphysiological range, they undergo remodeling, and manifest as pathologies such as fibrosis and calcification.

Research interest: We are interested in delineating the intricate link between valve mechanics and valve biology, to provide avenues for therapeutic intervention

Translational impact: We are developing new surgical techniques, devices, and materials that can restore or preserve the biomechanics of the valves, such that their durability is improved.

Project 1 - Mitral & tricuspid valve mechanics & surgical repair

The mitral and tricuspid valve have 3-dimensional structures that are anchored at various points to the cardiac chambers surrounding them. Dynamic motion of the cardiac chambers impacts the mechanics and kinematics of the valves, and thus their function is interrelated. In patients with dilated or dysfunction failing hearts, changes in the cardiac chambers also alters the valve geometries, restricting their closure in systole. This leads to leakage of blood through the valves, which increases mortality. Surgical and interventional techniques to restore mitral and tricuspid valve geometry are proposed, but their efficacy and long term impact are not known.

Biomechanics of mitral-valve left ventricular interactions

Fibrosis & its inhibition after valve repair

Hemodynamic efficacy of tricuspid valve repairs

Recent publication: Amedi A, Onohara D, Xu D, Suresh K, Padala M. Hemodynamic outcomes after undersizing ring annuloplasty and focal suture annuloplasty for surgical repair of functional tricuspid regurgitation. Journal of Thoracic and Cardiovascular Surgery. Accepted. August 2020. (PMID: pending)​

project 2: novel materials for durable heart valves

Currently used materials for heart valve repair and replacement are often durable for 7-10 years, after which structural degeneration and calcification are often evident. Especially among younger patients, who are likely to survive greater than a decade after their surgery, the need for materials with better durability, less risk of calcification, and that do not require life-long anti-coagulation could be useful. In our laboratory, we are working on both inventing new materials and modifying existing materials for a wide variety of cardiovascular applications, with the hope that one or more of these materials can be advanced to clinical use or into implants that can be deployed in patients with cardiovascular diseases or defects.

Use of reinforced ePTFE sheets for heart valve reconstruction

Biohybrid materials for cardiovascular implants

Project 3: transcatheter mitral & tricuspid valve therapies

The era of heart valve therapies is transitioning from open heart surgery to transcatheter interventions that can be performed in a beating heart, with catheters that are guided with imaging. We have developed a new repair technology that uses focal leaflet enhancement to correct functional mitral and tricuspid regurgitation. The Cardiac Leaflet Enhancer (CARLEN) is a miniature, anchor-less, implant that attaches to the native heart valve at the site of regurgitation, and immediately corrects FMR.