Tissue-Engineered Heart Valves: A Call for Mechanistic Studies.

Heart valve disease carries a substantial risk of morbidity and mortality. Outcomes are significantly improved by valve replacement, but currently available mechanical and biological replacement valves are associated with complications of their own. Mechanical valves have a high rate of thromboembolism and require lifelong anticoagulation. Biological prosthetic valves have a much shorter lifespan, and they are prone to tearing and degradation. Both types of valves lack the capacity for growth, making them particularly problematic in pediatric patients. Tissue engineering has the potential to overcome these challenges by creating a neovalve composed of native tissue that is capable of growth and remodeling. The first tissue-engineered heart valve (TEHV) was created more than 20 years ago in an ovine model, and the technology has been advanced to clinical trials in the intervening decades. Some TEHVs have had clinical success, whereas others have failed, with structural degeneration resulting in patient deaths. The etiologies of these complications are poorly understood because much of the research in this field has been performed in large animals and humans, and, therefore, there are few studies of the mechanisms of neotissue formation. This review examines the need for a TEHV to treat pediatric patients with valve disease, the history of TEHVs, and a future that would benefit from extension of the reverse translational trend in this field to include small animal studies.

Karl Viktor Hall: From In Situ Vein Bypass to the Tilting Disc Heart Valve Prosthesis.

In 1977, Karl Viktor Hall implanted a novel tilting disc heart valve prosthesis at Rikshospitalet in Oslo, Norway. The Medtronic-Hall valve was known for its excellent durability and low thrombogenicity. Hall popularized the use of the great saphenous vein in situ as an arterial shunt in the 1960s, made a metal stripper to lyse vein valves, and introduced electromagnetic flowmeters in vascular surgery. He performed the first coronary artery bypass graft in Scandinavia in 1969. Under his leadership the first heart transplantation and the first heart-lung transplantation were performed in Scandinavia by his successor Tor Frøysaker in 1983 and 1986, respectively.

Sir Donald Ross, pioneer aortic valve surgeon.

Tribute to Sir Donald Ross by David Wheatley, as read by Robert Kleinloog, President, Society of Cardiothoracic Surgeons of South Africa at the Annual Congress of the South African Heart Association 19 October 2014.

Personal glimpses into the evolution of truncus arteriosus repair.

Truncus arteriosus (common arterial trunk) is an uncommon but complex congenital heart anomaly. Until the early 1970s, typically, patients died between the age of a few weeks to six months. Congestive heart failure owing to large pulmonary blood flow and truncal valve regurgitation was the major cause of death until innovative surgical techniques were discovered. In 1963, Herbert Sloan at the University of Michigan completed the first repair using a nonvalved conduit with long-term survival (not reported until 1974). At the Mayo Clinic, Rastelli and McGoon studied and completed the first repair with a valved homograft in 1967. In 1976, Ebert used the 12-mm Hancock valved conduit in infants under six months of age (University of California, San Francisco). In Boston (mid-1980s), Jonas and Castañeda used aortic homografts, which greatly reduced bleeding as a postoperative complication. In the early 1990s, Bove (University of Michigan) reported outstanding results with an approach based on primary repair within the first few days of life for patients with truncus arteriosus. Improved prognosis for patients with truncus arteriosus resulted from these corrective operations by analyzing the natural history of this condition while applying innovative ideas, improved technology, and perioperative care.

Understanding the morphology of the specialized conduction tissues in congenitally malformed hearts.

To repair congenital heart defects by means of open heart surgery, the surgeon needs guidance about the location and distribution of the specialized conduction tissues, in order to avoid their direct damage and consequent conduction disturbances. This review addresses the historical steps of the morphological study of the conduction system in different types of heart defects, providing updated information about the subject.

Surgical ablation for atrial fibrillation.

This paper reviews the history of surgical procedures developed for eradication of atrial fibrillation (AF) during cardiac surgery for structural heart disease, and in patients with AF without other indication for cardiac surgery. Current evidence indicates that, despite their proven efficacy, the Cox-Maze procedure and its modifications require cardiopulmonary bypass and cannot be easily justified in the case of AF without other indication for cardiac surgery. In patients undergoing cardiac surgery for mitral valve disease, concomitant ablation techniques using modifications of the Maze and alternative energy sources appear to be safe and effective in treating AF, especially in non-rheumatic disease. Minimally invasive epicardial ablation has been recently developed and can be performed on a beating heart through small access incision ports. Various techniques combining pulmonary vein isolation, ganglionated plexi ablation, and left atrial lines have been tried. Initial results are promising but further clinical experience is required to establish ideal lesion sets, appropriate energy sources, and the benefit-risk ratio of such an approach in patients without other indication for cardiac surgery. The role of surgical ablation in the current management of AF is under investigation.