Tenth RESTORE Group Meeting: overview

A collaborative approach to congestive heart failure management has evolved within the International RESTORE Team comprised of cardiologists and surgeons, representing the four continents of North America (United States), Europe, South America and Asia. This group celebrated its 10th conference at the AATS meeting in San Francisco, and Table 1 lists the sites of prior gatherings. The goals of this integrated team include discussion and application of new concepts about understanding and managing the spectrum of diseases that cause dilated cardiomyopathy from ischemic, valvular and nonischemic causes. Interaction during meetings always includes input from non-RESTORE experts with novel views on CHF topics. Table 1. Summary of sites for the last 10 RESTORE meetings The initial data relating to RESTORE results following restoration after ischemic cardiomyopathy after anterior infarction was reported in JACC in 2000 [1] and this information was the surgical stimulus for development of the STICH trial; and 5-year RESTORE results were reported in 2004 [2]. A recent summary of the collaborative output was recently published in Heart Failure Reviews, a medical journal that asked the RESTORE team to describe the broad range of considerations, with data output occupying 10 manuscripts [3–12] that fill the entire Journal. This publication is predominantly distributed to cardiologists, whose evaluation of CHF patients and recognition of the restoration potential is seminal for the evolution of rebuilding anatomy to reunite form and function for clinical improvement. The diagnostic and follow-up role of MRI was presented to determine if this imaging modality could provide ‘one stop shopping’ to obtain several established clinical guidelines. These include recognition of the amount of asynergy, remote muscle evaluation, end systolic volume index, ejection fraction, wall thickness, viability of ischemic and remote muscle by gadolinium, mitral annular dimension, papillary muscle width, tagging to define deformation. Discrete result examples and time frames were generated to achieve this goal. A yardstick of geometric change during cardiac failure is the conversion of the normal elliptical ventricular shape to a spherical contour. This sphericity concept is based on a dimensional change that accounts for length and width of the overall chamber. Global heart sphericity changes normally occur in nonischemic disease, following chronic valve insufficiency, and late after extensive infarction with stretch of remote muscle. However, the infarction scar initially causes a nonuniform change in the damaged region, does not immediately affect global sphericity, but routinely deforms the apex to change regional ventricular conicity. The new ‘Apical Conicity Index’ is introduced by Di Donato to account for the nonuniform geometric change. Key notes to prognosis following restoration involve two vital categories of adequate myocardial protection and a technically competent geometric procedure. The registry of the RESTORE report of ∼1200 patients was reviewed, to compare restoration results when either cardioplegia or the beating heart were employed during rebuilding. Furthermore, an overall review of experimental studies performed in dilated failing hearts was presented to define differences in these methods’ capacity to nourish LV subendocardial muscle, the most vulnerable area to intraoperative ischemia. Issues related to recognition of the concept of ‘vascular remodeling’ were addressed, as well as providing guidelines for the importance of maintaining a mean perfusion higher pressure during restoration. Geometric principles of restoration have been linked to the spatial geometry of the left ventricle, as described by Torrent-Guasp who unfortunately passed away in early 2005. However, the structural basis for normal geometry was presented to the American Association of Clinical Anatomists in 2004. Arthur Dalley, the AACA President, stated during his introduction that ‘Modern technology changes many things but not anatomy, now the ventricular myocardial band has changed anatomy’. That comment sets the framework for future learning, and helical configuration concepts must be tested since they may become the end points as novel restoration procedures evolve. Fig. 1 shows the postulation of how heart failure alters normal geometric configuration. Fig. 2 displays the interaction between descending segment geometry from the normal heart model, MRI evidence of acceleration tracts from velocity curves from Jung et al. [13] at Freiburg, Germany and by corrosion casts by Gorodkov et al. [14] at the Bakoulev Scientific Institute in Moscow that define how the spiral ventricular muscle trabeculae compress blood in the cavity. The helical ventricular myocardial band described by Torrent-Guasp. The normal heart on the top has a transverse basal loop and a helical apical loop with fibers from the descending and ascending segments forming a helix and exhibiting a crisscross fiber orientation at approximately 60° angles (shown by arrows). The bottom tracing shows the dilated heart, where the apical loop becomes spherical, and the fiber orientation becomes more horizontal and resembles the transverse orientation of the basal loop that serves as a surrounding buttress. Comparison of the spiral trabeculae of myocardial fibers observed by corrosion casts by Gorodkov at Bakoulev Institute in Moscow (left), the descending segment of the apical loop of the helical ventricular myocardial band heart model described by Torrent-Guasp (center) and the velocity acceleration MRI studies of Jung, Markl, and Hennig at the University of Freiburg, Germany, that imply fiber orientation from these contours. A form/function relationship is evolving that sets conceptual guidelines for understanding underlying anatomy and planning restoration procedures. This conceptual background sets the stage to focus upon the new concept that becomes based upon the principle that restoration should create a more conical form; this shape-related end point differs from conventional methods that only address the visible disease. Underlying principles of ‘Form versus Disease’ was described, and this background philosophy initiated several novel CHF procedures in patients with ischemic and nonischemic disease. These clinical geometric goals were described in four papers that addressed fresh and reproducible configuration objectives in (a) dilated ischemic cardiomyopathy with ‘Left Ventricular Hypokinesia’ without scar, (b) ischemic cardiomyopathy that restores ventricular form by identifying new patch placement sites, rather than focusing only upon exclusion of scar, (c) recognition that septal geometric structure/function relationships must be understood to treat right ventricular failure, and (d) employment of using the preserved geometry scaffold in nondilated hearts with ischemic disease, as plans are evolved to use autogenous stem cells to cause synchronous regional contractile recovery in scarred hearts that did not undergo revascularization. This pilot data initiates a novel concept of developing a ‘microscopic and macroscopic’ approach to cardiac failure, whereby subsequent approaches may ultimately combine cell biology with surgical scaffold rebuilding by restoration. Spatial knowledge of the overall geometry of the ventricular chamber was also blended with recognition that natural papillary muscle position maintains the conical shape in the normal heart, but this position changes during dilation to impair mitral valve function by altering tethering, and simultaneously contribute to the sphere formation by widening the interpapillary muscle distance. Buffolo summarized his experience in using mitral valve replacement rather than repair to treat secondary mitral insufficiency in ischemic and nonischemic dilated cardiomyopathy. The approach of bringing the stretched and tethered papillary muscle into a new position adjacent to the annulus during mitral valve replacement restored shape, improved conicity, shrinks volume and allowed favorable late survival in far advanced NYHA patients with congestive heart failure. The final two reports relate to how geometry effects right ventricular function. The underlying analysis is linked to septal function, and new studies demonstrate why septal anatomy derives from the same geometric structures as the left ventricular free wall within the helical ventricular myocardial band. Sonomicrometer analyses imply that the septum should be considered the ‘right ventricular lion’, since the oblique fibers that form septal architecture are responsible for its vital twisting action. Clinical follow-up includes early pilot studies by Frigiola et al. [15] that demonstrate the advantages of restoring function by right ventricular rebuilding in patients presenting with right ventricular failure after chronic pulmonary regurgitation after tetralogy of Fallot repair. Substantial improvement of right ventricular function, and alleviation of ventricular arrhythmias followed reconstruction of septal architecture and exclusion of part of the dilated nonfunctional free wall during pulmonary valve replacement. This overview surveys the topics discussed during the recent RESTORE meeting. The contributors to this issue appreciate the European Journal of Cardiothoracic Surgery providing the opportunity to summarize these reports in a single publication that includes preliminary and completed studies of diagnosis and treatment of congestive heart failure. The meeting goal always includes seminal studies by the RESTORE team, together with sharing new looks at the CHF by participating non-RESTORE investigators. The initial RESTORE reports about ischemic cardiomyopathy after anterior infarction [2,16] reflects the initiation of the Group's broad scope of CHF interests. The broad series of manuscripts that follows this overview defines the breadth of interest and curiosity of the RESTORE membership.