Left atrial appendage mass.

Left atrial (LA) masses are known to be associated with peripheral embolization. Accurate identification of etiology is crucial because treatment strategies may differ. We present the case of a young woman, who was initially diagnosed with a LA thrombus and anticoagulated. The diagnosis was revised to a primary cardiac tumor after review of the echocardiographic findings. Surgical excision revealed an atrial myxoma in an unusual location.

A Score for Predicting Acute Kidney Injury After Coronary Artery Bypass Graft Surgery in an Asian Population.

OBJECTIVE: To develop a scoring system to predict acute kidney injury in Asian patients after coronary artery bypass grafting. DESIGN: A retrospective analysis of data collected in an institutional cardiac database. SETTING: A tertiary academic hospital in a large metropolitan city. PARTICIPANTS: The study comprised 954 patients with coronary artery disease. INTERVENTIONS: All patients underwent coronary artery bypass surgery with cardiopulmonary bypass but did not undergo any other concomitant procedures. MEASUREMENTS AND MAIN RESULTS: The main outcome measured was acute kidney injury as defined by the Acute Kidney Injury Network criteria. The following 6 clinical variables were independent predictors of kidney injury: age>60 years, diabetes requiring insulin, estimated glomerular filtration rate<60 mL/min/1.73 m(2), ejection fraction<40%, cardiopulmonary bypass time>140 minutes, and aortic cross-clamp time>100 minutes. These variables were used to develop the Singapore Acute Kidney Injury score. CONCLUSION: The Singapore Acute Kidney Injury score is a simple way to predict, at the time of admission to the intensive care unit, an Asian patient's risk of developing acute kidney injury after coronary artery bypass surgery.

Unravelling the proteome of degenerative human mitral valves.

Degenerative mitral valve disease (DMVD), which includes the syndromes of mitral valve prolapse (MVP) and flail leaflet, is a common valvular condition which can be complicated by mitral regurgitation and adverse cardiovascular outcomes. Although several genetic and other studies of MVP in dog models have provided some information regarding the underlying disease mechanisms, the proteins and molecular events mediating human MVP pathogenesis have not been unraveled. In this study, we report the first large-scale proteome profiling of mitral valve tissue resected from patients with MVP. A total of 1134 proteins were identified, some of which were validated using SWATH-MS and western blotting. GO annotation of these proteins confirmed the validity of this proteome database in various cardiovascular processes. Among the list of proteins, we found several structural and extracellular matrix proteins, such as asporin, biglycan, decorin, lumican, mimecan, prolargin, versican, and vinculin, that have putative roles in the pathophysiology of MVP. These proteins could also be involved in the cardiac remodeling associated with mitral regurgitation. All MS data have been deposited in the ProteomeXchange with identifier PXD000774 (http://proteomecentral.proteomexchange.org/dataset/PXD000774).

Fiber optic projection-imaging system for shape measurement in confined space.

A fiber-based projection-imaging system is proposed for shape measurement in confined space. Owing to the flexibility of imaging fibers, the system can be used in special scenarios that are difficult for conventional experimental setups. Three experiments: open space, closed space, and underwater are designed to demonstrate the strength and weakness of the system. It is shown that when proper alignment is possible, relatively high accuracy can be achieved; the error is less than 2% of the overall height of a specimen. In situations where alignment is difficult, significantly increased error is observed. The error is in the form of gross-scale geometrical distortion; for example, flat surface is reconstructed with curvature. In addition, the imaging fibers may introduce fine-scale noise into phase measurement, which has to be suppressed by smoothing filters. Based on results and analysis, it is found that although a fiber-based system has its unique strength, existing calibration and processing methods for fringe patterns have to be modified to overcome its drawbacks so as to accommodate wider applications.

Pushing the hybrid approach to the edges, three stories in one: a case report.

Background: Mitral annular calcification (MAC) is common in the elderly. Extensive calcification has been historically challenging for the cardiac surgeons, with traditional surgical approaches carrying significant risks. Less invasive approaches have recently been explored in an attempt to reduce this risk. Case summary: We report the case of a 75-year-old woman who presented with recurrent pulmonary oedema, due to severe MAC and mitral regurgitation. Her past medical history included bioprosthetic aortic valve replacement 5 years ago. Given the extensive MAC and the patient's frailty, a minimally invasive hybrid approach with direct implantation of a transcatheter balloon expandable Sapien 3 valve was selected to manage her. Although the post-surgical result was initially excellent with elimination of the mitral regurgitation, the patient's post-operative course was marked by two serious complications, namely, acute severe aortic regurgitation, due to rupture of the bioprosthetic valve's right cusp, and severe paravalvular leak of the Sapien valve, due to posterior migration towards the left atrium. These were managed successfully with emergency valve-in-valve implantation using the 'double chimney' technique for the bioprosthetic aortic valve, as well as transeptal valve-in-valve implantation of a 2nd Sapien valve in the mitral valve, which sealed the gap between the 1st Sapien and the calcified mitral annulus. Discussion: This case illustrates a less invasive approach for the management of severe MAC. Complications can still occur in this high-risk group of patients, and therefore, such cases should be managed with close collaboration between cardiac surgeons and cardiologists, in centres with high expertise.

Stroke prevention strategies for cardiac surgery: a systematic review and meta-analysis of randomized controlled trials.

BACKGROUND: Stroke is a much-feared complication of cardiac surgery, but existing literature on preventive strategies is fragmented. Hence, a systematic review and meta-analysis of stroke prevention strategies for cardiac surgery was conducted. METHODS: An electronic literature search was conducted to retrieve randomized controlled trials (RCTs) investigating perioperative interventions for cardiac surgery, with stroke as an outcome. Random-effects meta-analyses were conducted to generate risk ratios (RRs), 95% confidence intervals (95% CI), and forest plots. Descriptive analysis and synthesis of literature was conducted for interventions not amenable to meta-analysis, focusing on risks of stroke, myocardial infarction and study-defined major adverse cardiovascular events (MACE). RESULTS: Fifty-six RCTs (61 894 patients) were retrieved. Many included trials were underpowered to detect differences in stroke risk. Among pharmacological therapies, only preoperative amiodarone was shown to reduce stroke risk in one trial. Concomitant left atrial appendage closure (LAAC) significantly reduced stroke risk (RR = 0.55, 95% CI = 0.36-0.84, P = 0.006) in patients with preoperative atrial fibrillation, and there was no difference in on-pump versus off-pump coronary artery bypass grafting (CABG) (RR = 0.94, 95% CI = 0.64-1.37, P = 0.735). Much controversy exists in literature on the timing of carotid endarterectomy relative to CABG in patients with severe carotid stenosis. The use of preoperative remote ischemic preconditioning was not found to reduce rates of stroke or MACE. CONCLUSION: This review presents a comprehensive synthesis of existing interventions for stroke prevention in cardiac surgery, and identifies gaps in research which may benefit from future, large-scale RCTs. LAAC should be considered to reduce stroke incidence in patients with preoperative atrial fibrillation.

Controlled release of vancomycin from PEGylated fibrinogen polyethylene glycol diacrylate hydrogel.

Surgical site infection (SSI) is a common issue post-surgery which often prolongs hospitalization and can lead to serious complications such as sternal wound infection following cardiac surgery via median sternotomy. Controlled release of suitable antibiotics could allow maximizing drug efficacy and safety, and therefore achieving a desired therapeutic response. In this study, we have developed a vancomycin laden PEGylated fibrinogen-polyethylene glycol diacrylate (PF-PEGDA) hydrogel system that can release vancomycin at a controlled and predictable rate to be applied in SSI prevention. Two configurations were developed to study effect of the hydrogel on drug release, namely, vancomycin laden hydrogel and vancomycin solution on top of blank hydrogel. The relationship between the rigidity of the hydrogel and drug diffusion was found to comply with a universal power law, i.e., softer hydrogels result in a greater diffusion coefficient hence faster release rate. Besides, vancomycin laden hydrogels exhibited burst release, whereas the vancomycin solution on top of blank hydrogels exhibited lag release. A mathematical model was developed to simulate vancomycin permeation through the hydrogels. The permeation of vancomycin can be predicted accurately by using the mathematical model, which provided a useful tool to customize drug loading, hydrogel thickness and stiffness for personalized medication to manage SSI. To evaluate the potential of hydrogels for bone healing applications in cardiovascular medicine, we performed a proof-of-concept median sternotomy in rabbits and applied the hydrogels. The hydrogel formulations accelerated the onset of osteo-genetic processes in rabbits, demonstrating its potential to be used in human.

Influence of prosthesis type on long-term survival after re-replacement of aortic valve prosthesis.

BACKGROUND: The purpose of this study is to examine the influence of the prosthesis type on early mortality and long-term survival after re-replacement of aortic valve prosthesis, especially in patients over 60 years old. METHODS: Late outcome of 223 patients who underwent a reoperation on the aortic valve and received a mechanical (mechanical group) or biological (biological group) heart valve prosthesis at a single institution were analyzed for survival and major valve-related complications, including structural valve deterioration, thromboembolism, hemorrhage, further reoperation, and valve-related mortality. RESULTS: Preoperative New York Heart Association class IV (P = 0.001), emergency procedure (P = 0.002), and endocarditis (P = 0.025) were significant risk factors for 30-day mortality rates, which were 8.4 % and 12.5 %, respectively (mechanical versus biological group, P = 0.361). A subanalysis of elective patients revealed a low risk of 30-day mortality of 2.4 % and 1.8 %, respectively. Event-free survival was comparable at 5 years (73.9% ± 3.6% versus 70.5% ± 6.5%, mechanical versus biological group) and 10 year (49.7% ± 5.0% versus 35.3% ± 9.8%, mechanical versus biological group). In a propensity-matched subanalysis, survival and event-free survival were comparable at 5 and 10 years in both groups. CONCLUSION: The type of aortic valve prosthesis did not affect early outcome and late survival in patients who underwent valve replacement, and therefore, the current strategy favoring a biological aortic valve prosthesis for patients aged over 60 years in first-time operations could also be applied in re-replacement.

Predicting late aortic complications after acute type A dissection surgery with volumetric measurements in a Singapore cohort.

Introduction: This study was conducted to evaluate the efficacy of postoperative computed tomography (CT) measurements of aortic lumen volumes in predicting aortic-related complications following acute type A aortic dissection (ATAAD) repair. Methods: We conducted a single-institution retrospective aortic volumetric analysis of patients after ascending aorta replacement performed during 2001-2015. The volumetric measurements of total lumen (total-L), true lumen (TL), false lumen (FL), as well as the TL:FL ratio from the first and second postoperative computer angiograms were obtained. A generalised structural equation model was created to analyse the predictive utility of TL:FL ratio. Results: One hundred and twenty-five patients underwent surgical intervention, of whom 97 patients were eventually discharged and analysed for postoperative complications. A total of 19 patients were included in the final analysis. Patients with late postoperative aortic complications had a significantly higher FL volume and total-L volume on the first (FL volume P = 0.041, total-L volume P = 0.05) and second (FL volume P = 0.01, total-L volume P = 0.007) postoperative scans. The odds of having aortic complications were raised by 1% with a 1 cm3 increase in total-L volume and by 2% with a 1 cm3 increase in FL volume. The TL:FL ratio was significantly lower in patients who developed complications. Conclusion: Postoperative CT volumetric measurements in patients who developed complications are characterised by a significant increase in the FL volume and total-L volume from the first postoperative scans. Patients with disproportionately expanded FL presenting with TL:FL ratios less than 1 were associated with aortic complications. Hence, the TL:FL ratio may be a reliable and useful parameter to monitor postoperative disease progression and to evaluate the risk of late complications in ATAAD patients.

Effects of antibiotic treatment and phagocyte infiltration on development of Pseudomonas aeruginosa biofilm-Insights from the application of a novel PF hydrogel model in vitro and in vivo.

Background and purpose: Bacterial biofilm infections are major health issues as the infections are highly tolerant to antibiotics and host immune defenses. Appropriate biofilm models are important to develop and improve to make progress in future biofilm research. Here, we investigated the ability of PF hydrogel material to facilitate the development and study of Pseudomonas aeruginosa biofilms in vitro and in vivo. Methods: Wild-type P. aeruginosa PAO1 bacteria were embedded in PF hydrogel situated in vitro or in vivo, and the following aspects were investigated: 1) biofilm development; 2) host immune response and its effect on the bacteria; and 3) efficacy of antibiotic treatment. Results: Microscopy demonstrated that P. aeruginosa developed typical biofilms inside the PF hydrogels in vitro and in mouse peritoneal cavities where the PF hydrogels were infiltrated excessively by polymorphonuclear leukocytes (PMNs). The bacteria remained at a level of ~106 colony-forming unit (CFU)/hydrogel for 7 days, indicating that the PMNs could not eradicate the biofilm bacteria. ß-Lactam or aminoglycoside mono treatment at 64× minimal inhibitory concentration (MIC) killed all bacteria in day 0 in vitro biofilms, but not in day 1 and older biofilms, even at a concentration of 256× MIC. Combination treatment with the antibiotics at 256× MIC completely killed the bacteria in day 1 in vitro biofilms, and combination treatment in most of the cases showed significantly better bactericidal effects than monotherapies. However, in the case of the established in vivo biofilms, the mono and combination antibiotic treatments did not efficiently kill the bacteria. Conclusion: Our results indicate that the bacteria formed typical biofilms in PF hydrogel in vitro and in vivo and that the biofilm bacteria were tolerant against antibiotics and host immunity. The PF hydrogel biofilm model is simple and easy to fabricate and highly reproducible with various application possibilities. We conclude that the PF hydrogel biofilm model is a new platform that will facilitate progress in future biofilm investigations, as well as studies of the efficacy of new potential medicine against biofilm infections.

Meta-Analysis of Percutaneous Coronary Intervention Versus Coronary Artery Bypass Grafting for Left Main Narrowing.

Randomized controlled trials (RCTs) comparing percutaneous coronary intervention (PCI) with drug-eluting stents and coronary artery bypass grafting (CABG) for patients with left main coronary artery disease (LMCAD) have reported conflicting results. We performed a systematic review up to May 23, 2021, and 1-stage reconstructed individual patient data meta-analysis (IPDMA) to compare outcomes between both groups. The primary outcome was 10-year all-cause mortality. Secondary outcomes included myocardial infarction (MI), stroke, and unplanned revascularization at 5 years. We performed individual patient data meta-analysis using published Kaplan-Meier curves to provide individual data points in coordinates and numbers at risk were used to increase the calibration accuracy of the reconstructed data. Shared frailty model or, when proportionality assumptions were not met, a restricted mean survival time model were fitted to compare outcomes between treatment groups. Of 583 articles retrieved, 5 RCTs were included. A total of 4,595 patients from these 5 RCTs were randomly assigned to PCI (n = 2,297) or CABG (n = 2,298). The cumulative 10-year all-cause mortality after PCI and CABG was 12.0% versus 10.6%, respectively (hazard ratio [HR] 1.093, 95% confidence interval [CI] 0.925 to 1.292; p = 0.296). PCI conferred similar time-to-MI (restricted mean survival time ratio 1.006, 95% CI 0.992 to 1.021, p=0.391) and stroke (restricted mean survival time ratio 1.005, 95% CI 0.998 to 1.013, p = 0.133) at 5 years. Unplanned revascularization was more frequent after PCI than CABG (HR 1.807, 95% CI 1.524 to 2.144, p <0.001) at 5 years. This meta-analysis using reconstructed participant-level time-to-event data showed no statistically significant difference in cumulative 10-year all-cause mortality between PCI versus CABG in the treatment of LMCAD.

Minimally invasive tricuspid valve surgery and concomitant MAZE procedure with closure of LA appendage through an ASD.

Utilization of the ASD as a gateway to reach the left heart in tricuspid valve surgery may facilitate the use of a mini right thoracotomy and single atriotomy approach, avoiding the need for bi-atrial incisions and/or median sternotomy.

Sleep apnea and recurrent heart failure hospitalizations after coronary artery bypass grafting.

STUDY OBJECTIVES: Sleep apnea is prevalent in patients undergoing coronary artery bypass grafting (CABG). We investigated the relationship between sleep apnea and recurrent heart failure hospitalizations in patients undergoing nonurgent CABG. METHODS: Between November 2013 and December 2018, 1,007 patients completed a sleep study prior to CABG and were followed up until April 2020. Recurrent heart failure hospitalizations were analyzed by Poisson, negative binomial, Andersen-Gill, and joint frailty models, with partial and full adjustment for covariates. RESULTS: At an average follow-up of 3.3 years, the number of patients with 0, 1, or ≥ 2 heart failure hospitalizations were 908 (90.2%), 62 (6.2%), and 37 (3.7%), respectively. The total number of heart failure hospitalizations was 179, comprising 62 (35%) first and 117 (65%) repeat events. The numbers of heart failure hospitalizations for the sleep apnea (n = 513, 50.9%) and nonsleep apnea groups were 127 and 52, respectively. Negative binomial regression demonstrated that sleep apnea was associated with recurrent heart failure hospitalizations (fully adjusted rate ratio, 1.71; 95% confidence interval [CI], 1.12-2.62; P = .013). Similar results were found in Poisson (1.63; 95% CI, 1.15-2.31; P = .006), Andersen-Gill (1.66; 95% CI, 1.01-2.75; P = .047), and joint frailty models (1.72; 95% CI, 1.00-3.01; P = .056). CONCLUSIONS: In patients after CABG, repeat events accounted for two-thirds of heart failure hospitalizations. Sleep apnea was independently associated with recurrent heart failure hospitalizations. CITATION: Teo YH, Tam WT, Koo C-Y, et al. Sleep apnea and recurrent heart failure hospitalizations after coronary artery bypass grafting. J Clin Sleep Med. 2021;17(12):2399-2407.

A Novel Minimally Invasive Technique of Temporary Caval Occlusion for Right Heart Surgery.

Right heart surgery is challenging in the minimally invasive cardiac surgery setting, particularly in terms of caval isolation procedures in patients with enlarged and pressurized atria. We describe a novel minimally invasive caval occlusion technique with the use of a balloon catheter designed for temporary large vessel occlusion. A patient with a large ostium secundum atrial septal defect and significant shunt flow underwent a successful minimally invasive closure of the pathological connection between atria with a bovine pericardial patch. The utilized occlusion technique provided excellent visibility of the surgical site and may facilitate minimally invasive procedures in various clinical scenarios.

Meta-analysis of the benefit of beta-blockers for the reduction of isolated atrial fibrillation incidence after cardiac surgery.

Objectives: Postoperative atrial fibrillation (POAF) is a common problem of cardiac surgery. Beta-blockers are recognized as effective prophylactic agents available for POAF management. To better understand its effect on isolated atrial fibrillation after cardiac surgery, a meta-analysis was conducted. Methods: Randomized controlled trials (RCTs) were searched and filtered by comparing the efficacy of beta-blockers and control users in isolated POAF for cardiac surgery. Seventeen RCTs were identified and analyzed by typical meta-analysis methods. The search was performed from inception to May 31, 2020. Subgroup analyses were conducted for type of surgery and beta-blocker, starting time and route of administration of beta-blocker, and dosage of intravenous landiolol hydrochloride. Results: Beta-blockers were effective in reducing isolated POAF risk (risk ratio [RR], 0.52 [0.41, 0.66], P = .31, I2 = 12%). In subgroup analyses, beta-blocker administration during postoperative period (RR, 0.43 [0.29, 0.62], P = .84, I2 = 0%) and on-pump coronary artery bypass graft (RR, 0.34 [0.04, 3.15], P = .56, I2 = 0%) had lowest risk of isolated POAF incidence. Intravenous landiolol hydrochloride at 2 µg/kg/min also had low risk of isolated POAF occurrence. Conclusions: Beta-blocker treatment helps to reduce isolated atrial fibrillation incidence after cardiac surgery. Our subgroup analyses also reveal postoperative beta-blocker administration after on-pump coronary artery bypass graft surgery is most effective in reducing isolated POAF risk. Intravenous landiolol hydrochloride at a dosage of 2 µg/kg/min has also displayed favorable results. Further trials may be required to explore these factors.

Sleep apnea and diabetes mellitus are independently associated with cardiovascular events and hospitalization for heart failure after coronary artery bypass grafting.

The relative and combined effects of sleep apnea with diabetes mellitus (DM) on cardiovascular outcomes in patients undergoing coronary artery bypass grafting (CABG) remain unknown. In this secondary analysis of data from the SABOT study, 1007 patients were reclassified into four groups based on their sleep apnea and DM statuses, yielding 295, 218, 278, and 216 patients in the sleep apnea (+) DM (+), sleep apnea (+) DM (-), sleep apnea (-) DM (+), and sleep apnea (-) DM (-) groups, respectively. After a mean follow-up period of 2.1 years, the crude incidence of major adverse cardiac and cerebrovascular event was 18% in the sleep apnea (+) DM (+), 11% in the sleep apnea (+) DM (-), 13% in the sleep apnea (-) DM (+), and 5% in the sleep apnea (-) DM (-) groups. Using sleep apnea (-) DM (-) as the reference group, a Cox regression analysis indicated that sleep apnea (+) and DM (+) independently predicted MACCEs (adjusted hazard ratio, 3.2; 95% confidence interval, 1.7-6.2; p = 0.005) and hospitalization for heart failure (adjusted hazard ratio, 12.6; 95% confidence interval, 3.0-52.3; p < 0.001). Sleep apnea and DM have independent effects on the prognosis of patients undergoing CABG.Clinical trial registration: ClinicalTrials.gov identification no. NCT02701504.

Functional reservoir microcapsules generated via microfluidic fabrication for long-term cardiovascular therapeutics.

Cardiovascular disease is a chronic disease that leads to impaired cardiac function and requires long-term management to control its progression. Despite the importance of hydrogels for therapeutic applications, a contradiction between the size of a hydrogel and the amount of loaded drug has been encountered when using conventional fabrication methods. In this study, biocompatible reservoir microcapsules (diameter ∼100 µm) with a large liquid core and polymeric shell were fabricated via a one-step phase separation of poly(ethylene glycol)diacrylate (PEGDA) and dextran within pre-gel droplets through microfluidics. By controlling the process of phase separation, high drug-loading efficiency (∼80%) for long-term release (30 days) of vascular endothelial growth factor (VEGF) and platelet-derived growth factor (PDGF) was achieved. Drug molecules were dispersed within the liquid core at a concentration above saturation solubility for sustained delivery via regulation of the shells. Effective therapeutic enhancement of human umbilical vein endothelial cell (HUVEC) and umbilical artery smooth muscle cell (SMC) proliferation and tube formation in vitro promoted rapid cell proliferation and increased the number of migrated cells by ∼1.7 times. Moreover, in vivo blood vessel regeneration for cardiovascular control induced by sustained dual-drug (VEGF and PDGF) delivery to the rat heart was achieved, showing the effectiveness of long-term protein delivery in improving cardiac function and significantly reducing ventricular wall thickness and fibrosis of the infarct region. The ratio of heart tissue scarring was reduced to 11.2% after microcapsule treatment compared with 21.4% after saline treatment in the rat model. By using these reservoir microcapsules, similar sustained delivery of proteins, mRNAs and biologic drugs could be developed for the treatment of a range of long-term chronic diseases and regenerative medicine.