Clinical Effects of Surgical Left Atrial Reduction and Concomitant Mitral Valve Replacement in Patients with Giant Left Atrium

ABSTRACT Introduction: A giant left atrium may cause respiratory dysfunction and hemodynamic disturbance postoperatively. This retrospective study aimed to evaluate clinical effects of surgical left atrial reduction in concomitant cardiac valves operations. Methods: One hundred and thirty-five patients with heart valve diseases and giant left atriums from January 2004 to July 2021 were enrolled into this research. They were divided into the folded group (n=63) and the unfolded group (n=72). Patients in the folded group had undergone cardiac valve operations concomitantly with left atrial reductions. The perioperative characteristics were compared between both groups, and subgroup analysis was performed. Results: There were five deaths in the folded group and 25 deaths in the unfolded group (P<0.001). Complications including pneumonia, sepsis, multiple organs dysfunction syndrome, low cardiac output syndrome, and the use of continuous renal replacement therapy were significantly fewer in the folded group. The receiver operating characteristic curve of left atrial max. diameter predicting mortality was significant (area under the curve=0.878, P=0.005), and the cutoff point was 96.5 mm. The stratified analysis for sex showed that more female patients died in the unfolded group. Logistic regression for mortality showed that the left atrium unfolded, left atrial max. diameter, cardiopulmonary bypass time, and mechanical ventilation time increased the risk of death. Conclusion: Surgical left atrial reduction concomitantly with valves replacement could decrease mortality and was safe and effective in giant left atrium patients.

Mid-term outcome after tricuspid valve replacement

Abstract Objective: To evaluate the mid-term survival rate after tricuspid valve replacement (TVR). Methods: We retrospectively studied 110 consecutive patients who underwent TVR from January 2007 to November 2017. A survival analysis was performed with the Kaplan-Meier method and the log-rank test. Results: The median survival was 65.81 months. Mean age was 50 (range 39 to 59) years. Forty-eight patients (43.6%) were male, and 62 patients (56.4%) were female. Most of the patients (78.5%) were categorized into the New York Heart Association (NYHA) functional classes III/IV. Seventy-two patients (65.5%) had isolated TVR. Six-three patients (57.3%) had previously undergone heart surgery. The Kaplan-Meier survival rates at one year, three years, and five years were 59.0%±5%, 52.0%±6%, and 48.0%±6%, respectively. A Cox regression analysis demonstrated that the risk factors for mid-term mortality were advanced NYHA class (hazard ratio [HR] 2.430, 95% confidence interval [CI] 1.099-5.375, P=0.028), need for continuous renal replacement therapy (CRRT) treatment (HR 3.121, 95% CI 1.610-6.050, P=0.001), and need for intra-aortic balloon pump (IABP) treatment (HR 3.356, 95% CI 1.072-10.504, P=0.038). Conclusion: In TVR, impaired cardiac function before the operation and a need for CRRT or IABP treatment after the operation is independently associated with increased mid-term mortality.

Dact1 involvement in the cytoskeletal arrangement of cardiomyocytes in atrial fibrillation by regulating cx43

Abstract Objective: To determine the role of the dishevelled binding antagonist of beta catenin 1 (DACT1) in the cytoskeletal arrangement of cardiomyocytes in atrial fibrillation (AF). Methods: The DACT1 expression and its associations with the degree of fibrosis and β-catenin in valvular disease patients were analyzed by immunohistochemistry and Masson's staining. DACT1 was overexpressed in the atrial myocyte cell line (HL-1) and the cardiac cell line (H9C2) by adenoviral vectors. Alterations in the fibrous actin (F-actin) content and organization and the expression of β-catenin were detected by flow cytometry, immunofluorescence, and Western blotting. Additionally, the association of DACT1 with gap junctions connexin 43 (Cx43) was detected by immunohistochemistry, immunofluorescence, and Western blotting. Results: Decreased cytoplasmic DACT1 expression in the myocardium was associated with AF (P=0.037) and a high degree of fibrosis (weak vs. strong, P=0.028; weak vs. very strong, P=0.029). A positive association was observed between DACT1 and β-catenin expression in clinical samples (P=0.028, Spearman's rho=0.408). Furthermore, overexpression of DACT1 in HL-1 and H9C2 cells induced an increase in β-catenin and subsequent partial colocalization of DACT1 and β-catenin. In addition, F-actin content and organization were enhanced. Interestingly, DACT1 was positively correlated with the Cx43 expression in clinical samples (P=0.048, Spearman's rho=0.370) and changed the Cx43 distribution in cardiac cell lines. Conclusion: DACT1 proved to be a novel AF-related gene by regulating Cx43 via cytoskeletal organization induced by β-catenin accumulation in cardiomyocytes. DACT1 could thus serve as a potential therapeutic marker for AF.