A new procedure for elimination of atrial fibrillation associated with mitral valve disease: a proof-of-concept study

BACKGROUND

Left atrial enlargement and fibrosis have been linked to the pathogenesis of atrial fibrillation (AF). The authors aimed to introduce a novel concept and develop a new procedure for AF treatment based on these characteristics.

METHODS

The study included three stages. The first stage was a descriptive study to clarify the characteristics of the left atrial enlargement and fibrosis' distribution in patients with mitral valve disease and long-standing persistent AF. Based on these characteristics, the authors introduced a novel concept for AF treatment, and then translated it into a new procedure. The second stage was a proof-of-concept study with this new procedure. The third stage was a comparative effectiveness research to compare the clinical outcomes between patients with this new procedure and those who received Cox-Maze IV treatment.

RESULTS

Based on the nonuniform fashion of left atrial enlargement and fibrosis' distribution, the authors introduced a novel concept: reconstructing a left atrium with appropriate geometry and uniform fibrosis' distribution for proper cardiac conduction, and translated it into a new procedure: left atrial geometric volume reduction combined with left appendage base closure. As compared to the Cox-Maze IV procedure, the new procedure spent significantly shorter total surgery time, cardiopulmonary bypass time, and aortic cross-clamp time ( P <0.001). Besides, the new procedure was related to a shorter ICU stay period (odd ratio (OR)=0.45, 95% CI=0.26-0.78), lower costs (OR=0.15, 95% CI=0.08-0.29), and a higher rate of A wave of transmitral and transtricuspid flow reappearance (OR=1.76, 95% CI=1.02-3.04).

CONCLUSIONS

The new procedure is safe and effective for eliminating AF associated with mitral valve disease.

Anesthetic Considerations for a Novel Method of Surgical Ventricular Remodeling Using the BioVentrix Revivent TC System

Surgical ventricular remodeling (SVR) is an invasive method of treating patients with heart failure who also have ischemic cardiomyopathy and reduced ejection fraction (EF). Introduced in the mid-1980s, this technique was met with varying success and relatively high morbidity and mortality despite its theoretical benefits. The development of the BioVentrix Revivent TC System (BioVentrix, Inc., San Ramon, CA) as a less-invasive method of surgical ventricular remodeling has created a novel, multidisciplinary approach to heart failure management, which necessitates multiple subspecialties. Currently in the trial phase in the United States and widely used in Europe, the positive results to date appear promising for the rapid adoption of this procedure. For the cardiac anesthesiologist, a thorough understanding of the patient population, procedural goals, and intraoperative management is essential. This overview discusses the advancement in surgical ventricular remodeling, the pertinent surgical steps of the BioVentrix Revivent TC System placement, and specific anesthetic considerations for this novel procedure.

First Successful LVAD Implantation After BioVentrix Revivent TC Ventricular Reshaping

The Revivent TC System (BioVentrix Inc, San Ramon, CA) enables a less invasive approach for left ventricular reshaping and scar exclusion in selected patients with ischemic cardiomyopathy. Although the system is designed to improve quality of life and to promote reverse remodeling, patients can still progress to end-stage heart failure requiring advanced therapies. This report describes a case of left ventricular assist device surgery in a patient 16 months after Revivent System implantation. The planning process and surgical technique proved to be complex. This case report can help provide guidance to advanced heart failure teams who encounter patients with the Revivent System who require left ventricular assist device support.

Left ventricular surgical remodeling 2.0

Left ventricular surgical remodeling has been, for a long time, the procedure applied for large dyskinetic, or akinetic, areas as a consequence of a myocardial infarction, mainly located in the left anterior descending area. Many surgical techniques were developed, aimed to a pure reduction of the volume of the left ventricular (LV) cavity or to add to volume reduction a more physiologic conical shape. The expansion of interventional procedures invaded most of the fields before treated only by cardiac surgeons. In this issue, Pillay describes a hybrid technique, involving both interventional cardiologists and cardiac surgeons, aimed to LV volume reduction after an anterior myocardial infarction. A series of internal (right ventricular septum) and external (anterior wall) anchors are implanted to approximate the LV free wall to the anterior septum, consequently excluding the scarred myocardium. Although some limitations of this study, the authors have to be commended for having revitalized a procedure almost eliminated from the surgical scenario.

Autophagy during left ventricular redilation after ventriculoplasty: Insights from a rat model of ischemic cardiomyopathy

OBJECTIVES

Myocardial autophagy has been recognized as an important factor in heart failure. It is not known whether changes in ventricular geometry by left ventriculoplasty influence autophagy in ischemic cardiomyopathy. We hypothesized that myocardial autophagy plays an important role in left ventricular (LV) redilation after ventriculoplasty.

METHODS

Four weeks after ligation of the left anterior descending artery, ventriculoplasty or sham operation was performed. The animals were euthanized at 2 days (early) or 28 days (late) after the second operation. Ventricular autophagy was evaluated by protein expression of microtubule-associated protein light chain 3 II, an autophagosome marker. Cardiomyocyte area was assessed by histologic examination. LV function was evaluated by echocardiography. To examine the implications of autophagy, an autophagy inhibitor (3-methyladenine) was injected intraperitoneally for 3 weeks before sacrifice.

RESULTS

The LV was reduced in size early and redilated late after ventriculoplasty. LV systolic function was improved early and later worsened after ventriculoplasty. Light chain 3 II expression decreased early after ventriculoplasty and increased in the late period. Myocyte area increased from the early to late stage after ventriculoplasty. Autophagic inhibition exaggerated the increased myocyte hypertrophy and LV redilation.

CONCLUSIONS

In a rat model of myocardial infarction, autophagy decreased early after ventriculoplasty and increased again during LV redilation. These results provide new insights into the mechanism underlying the late failure of ventriculoplasty.