Ani C. Anyanwu

Seeking a Higher Standard for Degenerative Mitral Valve Repair: Begin with Etiology

doi:10.1016/j.jtcvs.2007.10.060 D espite the widely held consensus that valve repair is the preferred surgical treatment for patients suffering from degenerative mitral valve disease, valve replacement for this condition remains all too prevalent. In the past few years interest in mitral valve repair has expanded among cardiologists and surgeons, with the recognition that asymptomatic patients with severe mitral regurgitation may be candidates for surgery provided they are likely to undergo valve repair and obtain a durable result. We address both issues in the context of a recent article published in the Journal, which explored the results of mitral valve repair in degenerative disease according to etiologic classification – Barlow’s disease or fibroelastic deficiency. Most reports in the mitral valve repair literature define patient subsets on the basis of leaflet dysfunction (posterior, anterior or bileaflet prolapse) and repair techniques (chordal shortening or artificial chordoplasty; annuloplasty ring or no annuloplasty ring, etc.), without clarification of the etiology of degenerative disease. Furthermore, these studies traditionally used patient survival and freedom from re-operation as the principal indicators of a durable result. Recently, however, it has been appreciated that a proportion of patients free from reoperation after mitral valve repair have significant recurrent mitral regurgitation implying that freedom from reoperation is not a robust measure of durability of mitral valve repair. In their recent article, Flameng and co-workers introduced a fresh dimension into mitral valve repair outcomes research, by attempting to define the long-term outcome of mitral valve repair, including the freedom from recurrent mitral regurgitation, on the basis of etiology of degenerative mitral valve disease. Their data suggest, perhaps surprisingly, that, provided the surgical techniques were optimal, patients have a similar rate of recurrent regurgitation after mitral valve repair regardless of whether the original disease was Barlow’s or fibroelastic deficiency. There are several limitations in their analysis which deserve emphasis and suggest the need for further study, including retrospective classification of etiology and non-standardized and evolving surgical techniques – both of which limit the robustness of outcomes data. Nonetheless, this emphasis on etiologic classification in outcomes analysis of degenerative mitral valve repair is significant. We believe accurate etiologic classification is crucial to outcomes research, and indeed to achieving a higher standard of clinical care, as it does not seem logical that degenerative valves with very diverse characteristics (Figure 1a, 1c) are considered the same.

Surgical Strategies for Functional Tricuspid Regurgitation

Functional or secondary tricuspid regurgitation commonly is found in the setting of left-sided heart disease and, when severe, is associated with substantially poorer functional outcomes and survival if untreated. The traditional view that functional tricuspid regurgitation generally resolves with surgical correction of the primary lesions is no longer held. Data showing late development of severe tricuspid regurgitation in patients with mild regurgitation at time of mitral valve surgery have heralded a new era of aggressive intervention on the tricuspid valve. Tricuspid ring annuloplasty can be performed with minimal incremental morbidity and negligible additional mortality. Therefore, in addition to patients with severe regurgitation, annuloplasty is now also recommended for patients with risk factors for developing late tricuspid insufficiency (typically patients with moderate tricuspid regurgitation or severe annular dilation at time of left-sided cardiac procedures). In this work we review the current indications for tricuspid valve repair in patients undergoing other cardiac surgery operations and also the various options available to the surgeon.

Functional tricuspid regurgitation in mitral valve disease: epidemiology and prognostic implications.

In this review we summarize the data on epidemiology and natural history of functional tricuspid valve regurgitation as it applies to surgery for mitral valve disease. Tricuspid regurgitation in the context of mitral valve disease is frequent and is associated with substantial reduction in survival and quality of life. In many patients, the correction of left-sided cardiac lesions does not lead to resolution of tricuspid regurgitation. Significant tricuspid regurgitation after mitral valve surgery portends a poor prognosis, a course that is often not altered by subsequent surgical therapy. Although a liberal approach to tricuspid annuloplasty is widely practiced, the evidence that this approach alters the natural history of functional tricuspid regurgitation is not yet available, so it is not certain how much of the negative impact of tricuspid regurgitation is causative, rather than confounding, and to what degree we will improve long-term outcomes of mitral valve surgery by liberal tricuspid annuloplasty.

IMPLANTABLE CARDIOVERTER-DEFIBRILLATORS DO NOT REDUCE MORTALITY IN PATIENTS WITH THE HEARTMATE II LEFT VENTRICULAR ASSIST DEVICE

The clinical significance of ventricular tachycardia/ventricular fibrillation (VT/VF) in patients with the HeartMate II (HMII) left ventricular assist device (LVAD) has not been well elucidated. Accordingly, the role of implantable cardioverter-defibrillators (ICDs) in this patient population

Current concepts in Barlow’s valve reconstruction

Degenerative mitral valve diseases constitute a spectrum of lesions, varying from simple chordal rupture involving prolapse of an isolated segment in an otherwise normal valve to multisegmental prolapse involving one or both leaflets in a valve with significant excess tissue and a large annular size. Barlow syndrome is the most advanced and complex entity in this spectrum and is distinguished by the characteristic presence of diffuse and complex redundancy of the valve due to myxomatous degeneration (◘ Fig. 12.1a), producing prolapse of multiple segments in one or both leaflets (◘ Fig. 12.1b). Severe annular dilatation with giant valve size is evident (ring size ≥36 mm). In addition, varying degrees of annular calcification is often observed, as well as subvalvular fibrosis and calcification of the papillary muscles, in particular the anterior papillary muscle (◘ Fig. 12.1c). Therefore, surgical repair of the Barlow valve may present specific challenges. In this chapter, we describe our systematic approach to Barlow valve repair; we have found it to possible to repair essentially all Barlow valves by consistent application of the outlined principals.

Functional Tricuspid Regurgitation: Introduction

Functional or secondary tricuspid regurgitation typically refers to tricuspid regurgitation occurring secondary to left-sided heart disease, or pulmonary hypertensive disease, in the absence of organic lesions of the tricuspid valve. Until recently, “surgical abstention” has been the norm in dealing with functional tricuspid regurgitation, with the assumption that tricuspid regurgitation should resolve once the primary cause (typically mitral stenosis or regurgitation) is eliminated. This historical conservative approach to tricuspid regurgitation continues to tailor surgical practice to the present day, and tricuspid valve annuloplasty remains an infrequent operation in most surgical practices. Increasingly, however, there are reports in the literature supporting a more aggressive role for surgery in the prevention and treatment of functional tricuspid regurgitation. We have dedicated the cardiac section of this issue of the Seminars in Thoracic and Cardiovascular Surgery to exploring the pathophysiological, epidemiologic, and clinical basis for a more aggressive approach to management of functional tricuspid regurgitation. In 6 articles, invited experts in valvular heart disease have provided a thorough review of the current state of opinion and practice as regards functional tricuspid valve regurgitation. Although the articles are written mostly from the perspective of treating the patient with mitral valve disease, the principles apply to other causes of functional tricuspid regurgitation. The first 3 articles focus on the basis for intervention on functional tricuspid regurgitation. In the first article, myself and Dr. Adams review the epidemiology of functional tricuspid regurgitation, including the natural history, prognosis, and the current evidence base for practice. Although severe tricuspid regurgitation is undoubtedly associated with increased morbidity and reduced long-term survival, we note that the evidence on which current practice is determined is weak. Although it is likely that increased use of tricuspid annuloplasty will reduce the morbidity and mortality of functional tricuspid regurgitation, we do not at present have sufficiently robust data demonstrating such benefit. Next, Dr. Hung reviews the pathogenesis of functional tricuspid regurgitation and describes the annular and ventricular mechanisms underlying the development of

Surgical Pulmonary Embolectomy

Pulmonary embolectomy is one of the oldest cardiac operations, dating back to the early 20th century. Initially performed blindly as a closed cardiac procedure, the operation is now performed on cardiopulmonary bypass with clots extracted from the opened pulmonary arteries under direct vision. Surgery was the mainstay of therapy for pulmonary emboli in the 1960s and 1970s. Presently, however, with the advent of effective nonsurgical therapy, pulmonary embolectomy is largely reserved for anatomically extensive central emboli with hemodynamic compromise or right ventricular strain, or for cases in which medical therapy has failed or is contraindicated. The results of surgery have improved greatly in recent years, with contemporary series reporting mortality rates below 10%. Patient selection and surgical management are the key to minimizing the mortality of this operation. If patients are operated on at an early stage, before the onset of irreversible right ventricular dysfunction or protracted cardiogenic shock, then the mortality risk is low. On the other hand, preoperative cardiac arrest leads to a fivefold increase in mortality. Modern intraoperative management includes cardiopulmonary bypass, avoidance of cardiac ischemia, extraction of clots under direct vision only, and placement of cava filters. Some patients are not suitable for pulmonary embolectomy, including those undergoing cardiopulmonary resuscitation, those with predominantly peripheral emboli, and patients who do not have immediate access to cardiac surgery (thrombolysis is preferable to a delay in treatment). On the other hand, in centers with the infrastructure for immediate embolectomy, surgery offers the fastest means of deobliterating the pulmonary arteries and should thus be considered as a therapeutic option in all patients with massive or even submassive pulmonary embolism.