Transcatheter Valve Repair

Abstract

Modern interventional cardiology is grounded in the perfor-mance of percutaneous coronary interventions. However, begin-ning with the introduction of atrial septostomy and then followedby percutaneous balloon valvuloplasty, noncoronary interven-tions have provided a growing contribution to general proceduresin the cardiac catheterization laboratory. Today, up to 30% of allinterventions reflect a growing list of both peripheral proceduresand cardiac noncoronary interventions for structural and valvularheart disease.The first successful valvular interventions, namely balloonvalvuloplasty for pulmonic, mitral, and aortic stenosis, wereperformed more than 20 years ago, but only recently havesuccessful interventions for aortic stenosis and regurgitant val-vular disease been developed and attempted. The combination ofthese valvular interventions, other interventions for patients withstructural heart disease, and the growing population of adultswith congenital heart disease provide the basis for a whole newsubspecialty within interventional cardiology. This book is oneof the first to specifically address this new subspecialty. It wascompiled by a who’s who of pioneers in this new field. To besuccessful, this book must meet numerous challenges. First, ithas to deal with a rapidly moving and developing field. Second,it must bridge the worlds of adult cardiology, pediatric cardiol-ogy, and adults with congenital heart disease. Next, it must dealwith the pathophysiology of 4 very different valves and theirassociated lesions. Finally, it must cover a wide spectrum ofknowledge for cardiologists, who diagnose these illnesses, havepreviously treated them with medications, and now must under-stand mechanical interventions, as well as cardiac surgeons, whotypically see later stages of these diseases and treat them verydifferently. Despite these challenges, this book is admirablysuccessful at achieving all of these goals.The book is divided into 6 sections, the first 4 of which treateach of the valves separately. The fifth and sixth sectioncomprise 1 chapter each on tissue engineering and valve testing.The first section addresses the pulmonary valve. Chapters dealwith embryology, pathophysiology, and treatments, includingpulmonary valve replacement. The hemodynamic evaluationreflecting the perspective of both pediatric and adult patients isnicely divided between 2 chapters. One criticism of this sectionis the lack of a specific chapter on balloon valvuloplasty in bothchildren and adults, particularly as this was the first successfulapplication of percutaneous treatment for a valve lesion.The second section deals with the aortic valve and hasparticularly elegant chapters on echocardiographic and hemody-namic assessment. The impact of new percutaneous techniquesforaorticvalvereplacementandthesurgicalresultsaredescribedin 3 chapters. The results with percutaneous valve replacementfor aortic stenosis are described in separate chapters dealing withthe Edwards valve and the CoreValve, as well as a futuristicchapter on a nano-synthesized metallic valve. This section couldbenefit from a chapter on the embryology of aortic valve disease.In addition, the chapter on the history of nonsurgical aortic valvereplacement could be expanded to include information on clini-cal trial design and patient selection for this new therapy.The third section deals with the mitral valve and has 2 chapterson the embryology and etiology of mitral valve disease. Therewas some duplication between these 2 chapters, but they are bothwell written. Even though both chapters describe mitral stenosis,there is again no chapter or discussion in detail of percutaneousballoon valvuloplasty for rheumatic disease. The chapter onsurgical therapy emphasizes repair techniques, with only sparsedata on valve replacement and the outcomes. There is a gooddescription of percutaneous edge-to-edge repair utilizing the cliptechnique, as well as a good chapter on percutaneous coronarysinus indirect annuloplasty. The suture-based edge-to-edge leaf-let repair technique that is now in phase I clinical trials was notcovered in this section and will need to be added to futureadditions.Finally, the tricuspid valve is dealt with in section IV. There is anexcellent chapter on cardiac magnetic resonance imaging, but noembryologic discussion. The hemodynamics, surgical treatment,and the development of one device for percutaneous replacement ofthe tricuspid valve comprise the remaining chapters.Sections V and VI probably do not deserve separate sections atthe present time, given that there is only 1 chapter in each.Nonetheless, the use of heart valve tissue engineering and theimportance of valve testing represent important additions to thebook. In this regard, the chapter on valve testing is interesting,but should be supplemented by more discussions of trial designand the Food and Drug Administration pathways to approval.Overall, the book is an excellent compilation of a fast andnewly developing field. There is liberal use of color illustrations.In the future, the use of videos or movies on an accompanyingCD or DVD might be considered. Most of the chapters arerelatively short and concise. Some of the information on basicpathophysiology and surgery is available elsewhere, although theinclusion of this information in this book allows a singlereference for this and the clinical information on percutaneoustechniques for valvular repair and replacement.I think cardiologists, both pediatric and adult, and cardiacsurgeons will find something of interest in this book. As this fielddevelops and more clinical information becomes available, it islikely that future editions will include more outcomes data andwill allow this first-rate book to develop into a classic.