Prakash Punjabi

Introduction Our aim is to describe the use of cardiopulmonary exercise testing in watchful waiting for asymptomatic severe primary mitral regurgitation. Methods Between October 2016 and October 2017, ten patients with asymptomatic severe primary mitral regurgitation underwent watchful waiting in a single centre. Baseline assessment included history, physical examination, transthoracic echocardiogram and cardiopulmonary exercise testing. Patients were re-evaluated every 6 months with history, physical examination and transthoracic echocardiogram; and at 12 months with cardiopulmonary exercise testing. Results At 1 year follow up, five patients remained asymptomatic with no significant change in left ventricular ejection fraction ( p = 0.18). This was associated with no significant change in cardiopulmonary exercise testing parameters. However, five patients developed early new symptoms or changes in echocardiographic parameters with a significant fall in left ventricular ejection fraction ( p < 0.01). This was associated with a significant fall in anaerobic threshold ( p = 0.04) and four of the five patients having an abnormal percentage predicted peak VO2 at 1 year follow up. Conclusions Changes in symptomatic status or echocardiographic parameters during a watchful waiting approach for asymptomatic severe primary mitral regurgitation is associated with a significant reduction in cardiopulmonary exercise testing parameters.

Medical soft robotics constitutes a rapidly developing field in the treatment of cardiovascular diseases, with a promising future for millions of patients suffering from heart failure worldwide. Herein, the present state and future direction of artificial muscle‐based soft robotic biomedical devices in supporting the inotropic function of the heart are reviewed, focusing on the emerging electrothermally artificial heart muscles (AHMs). Artificial muscle powered soft robotic devices can mimic the action of complex biological systems such as heart compression and twisting. These artificial muscles possess the ability to undergo complex deformations, aiding cardiac function while maintaining a limited weight and use of space. Two very promising candidates for artificial muscles are electrothermally actuated AHMs and biohybrid actuators using living cells or tissue embedded with artificial structures. Electrothermally actuated AHMs have demonstrated superior force generation while creating the prospect for fully soft robotic actuated ventricular assist devices. This review will critically analyze the limitations of currently available devices and discuss opportunities and directions for future research. Last, the properties of the cardiac muscle are reviewed and compared with those of different materials suitable for mechanical cardiac compression.

Coronary artery bypass grafting remains the treatment of choice for a large cohort of patients with significant coronary disease. Despite the increased use of arterial grafts, the long saphenous vein remains the most commonly used conduit. Long-term graft patency continues to be the Achilles heel of saphenous vein grafts. This is due to the development of intimal hyperplasia, a chronic inflammatory disease that results in the narrowing and occlusion of a significant number of vein grafts. Research models for intimal hyperplasia are essential for a better understanding of pathophysiological processes of this condition. Large animal models resemble human anatomical structures and have been used as a surrogate to study disease development and prevention over the years. In this paper, we systematically review all published studies that utilized large animal models of vein graft disease with a focus on the type of model and any therapeutic intervention, specifically the use of external stents/mesh.