A. Gillinov

Surgical left atrial appendage occlusion : evaluation of a novel device with magnetic resonance imaging

OBJECTIVE Management of the left atrial appendage (LAA) is considered an important adjunct to ablation in cardiac surgical patients with atrial fibrillation (AF). However, current surgical techniques, both cut-and-sew and stapling, have been associated with incomplete LAA occlusion and complications. Using cardiac magnetic resonance imaging (MRI), we studied the safety and effectiveness of a new device for LAA occlusion in a primate model. METHODS Seven adult baboons underwent off-pump placement of an LAA clip (AtriCure Inc., Westchester, Ohio). LAA occlusion was confirmed intraoperatively by direct incision. All animals had MRI before and after clip placement to assess LAA perfusion, architecture, and overall cardiac function. Pathologic and histological studies were performed at 7, 30 and 180 days. RESULTS Clip placement was successful in all (n=7) without any clip related complications. Complete LAA occlusion was demonstrated intraoperatively in all subjects. LAA occlusion was confirmed on pre-sacrifice MRI, and left and right ventricular function were unchanged from preoperative studies; however, clip placement caused small reductions in left ventricular end-diastolic, end-systolic, and stroke volumes. At sacrifice, direct inspection confirmed stable location, persistent LAA exclusion, tissue in-growth and homogenous epithelialization without damage to adjacent structures. Histological analysis revealed a regular in-growth pattern in all studied specimens. CONCLUSION We demonstrated a safe, straightforward, persistent and effective method for LAA occlusion with this new LAA clip. MRI effectively demonstrated LAA occlusion and only minor changes in left ventricular volumes.

Impact of additive mitral valve surgery to coronary artery bypass grafting on mortality in patients with coronary artery disease and ischaemic mitral regurgitation: a systematic review and meta-analysis of randomized trials and observational studies

Aims Treatment of ischaemic mitral regurgitation (IMR) remains controversial. While IMR is associated with worse outcomes, randomized controlled trials (RCTs) and observational studies provided conflicting evidence regarding the benefit of mitral valve replacement (MVR) or repair (MVr) in addition to coronary artery bypass grafting (CABG). We conducted a meta-analysis incorporating data from published RCTs and observational studies comparing CABG vs. CABG + MVR/MVr. Methods and results We searched PubMed, MEDLINE, Embase, Ovid, and Cochrane for RCTs and observational studies comparing CABG (Group 1) vs. CABG + MVR/MVr (Group 2). Outcome was 30-day and 1-year mortality after surgical intervention. Mantel-Haenszel odds ratio (OR) was calculated using random-effects meta-analysis for the outcome. Heterogeneity was assessed by I2 statistics. Four RCTs and 11 observational studies met the inclusion criteria (5781 patients, 507 in RCTs, 5274 in observational studies). Group 1 vs. 2 weighted mean left ventricular ejection fraction in RCTs and combined RCTs/observational studies was 41.5 ± 12.3 vs. 40.3 ± 10.4% ( P -value = 0.24) and 45.5 ± 7.2 vs. 38 ± 10% ( P -value < 0.001), respectively. In RCTs, there was no difference in 30-day [OR: 0.95, 95% confidence interval (95% CI): 0.30-3.08, P = 0.94] or 1-year (OR: 0.90, 95% CI: 0.43-1.87, P = 0.78) mortality, respectively. For combined RCTs/observational studies, there was no difference in mortality at 30 days (OR: 0.67, 95% CI: 0.43-1.04, P = 0.08) or at 1 year (OR: 0.90, 95% CI: 0.7-1.15, P = 0.39). Conclusion In a meta-analysis of RCTs and observational studies of IMR patients, the addition of MVR/MVr to CABG did not improve survival.

Reply to Tavlasoglu et al.

We are very pleased with the interest shown in our paper and the recognition of this common clinical problem [1]. The authors provided an in-depth validation and analyses of some of the existing makeshift methods and related suction pressures; however, we did not aim to collect this sort of data in our clinical study. The purpose of our study was to determine the incidence of chest tube clogging and the role of bedside evaluation of potential issues with chest tubes. The data in our first prospective study demonstrated the incidence of chest tube clogging to be 36% [2]. We noted that the internal end of the chest tube (portion inside the body) was occluded in 86% of those patients even when the external portion appeared clear and that the degree of clogging cannot be always appreciated by the nurses and care providers in the intensive care units prior to removal. So it is not uncommon for caregivers to think that they have cleared the tube with makeshift bedside techniques, when in fact, the tube is still partially or completely occluded. Thus, possible solutions to address this must be optimized to maintain the chest tube lumen clear for the whole length of the tube, provide controlled clot removal and/or prevent clogging, especially at the ‘functional’ portion of the catheters where the sideand end-holes collect the shed blood and/or fluids from within the chest. It is also important to consider that there is no consensus regarding the best practice for chest tube management and maintenance of patency [3, 4]. Strategies for establishing patency include but are not limited to makeshift methods such as milking, tapping, fanfolding several layers of tubing and squeezing, handover-hand and/or hand-held, or roller stripping manipulations, which all can be effective in selected clinical situations. Tavlasoglu et al. add to the options with their well-described ‘fanfolding modification’, which addresses some of the concerns of the other makeshift techniques. However, all of them generate uncontrolled changes in intrathoracic pressure and may cause bidirectional dislodgement of clots [5]. As cardiac surgery patients are becoming generally more complicated and bleeding represents a growing issue with the use of powerful anti-platelet agents, the problem of clogging may grow. Further efforts to understand how to prevent this are needed. Thus, it is important to recognize that clogged and dysfunctional chest tubes represent a real clinical issue.

GENDER DIFFERENCES IN THE ETIOLOGY OF MITRAL VALVE DISEASE

Background: Women historically have poorer outcomes following mitral valve surgery. This study sought to define gender differences in the etiology of valve disease for patients undergoing mitral valve surgery. Methods: We retrospectively analyzed primary mitral valve pathology for all patients who

PROGNOSTIC SIGNIFICANCE OF GLOBAL LONGITUDINAL STRAIN AND CORRECTION OF PRIMARY MITRAL REGURGITATION IN PATIENTS WITH PRESERVED LEFT VENTRICULAR EJECTION FRACTION

The prognostic significance of baseline LV-global longitudinal strain (LV-GLS) in asymptomatic/minimally symptomatic patients with ≥3+ primary mitral regurgitation (PMR) & preserved LVEF (≥60%) late following medical management or surgical correction is unknown. Among 1202 patients (61±13

IMPACT OF BASELINE PULMONARY PRESSURES ON LONG-TERM OUTCOME IN MYXOMATOUS MITRAL REGURGITATION: THRESHOLD OR PROGRESSIVE EFFECT?

We sought to assess impact of pulmonary hypertension on long-term outcomes in patients with significant myxomatous mitral regurgitation (MMR). We studied 1318 patients (age 62±13 years & 66% men) with ≥3+ MMR on resting echo, evaluated at our center from 2005-8. Baseline clinical & echo data