In Vivo Findings of a Novel Focal Ablation Catheter: Focused Electric Field Catheter Tip.

Current catheter designs used for radiofrequency (RF) in cardiac tissue achieve limited ablation depth as lesion size is driven heavily by resistive heating at the tissue surface. A catheter with a truncated, dome-shaped tip with a toroidal surface designed for focal RF ablation was recently described. This in vivo study compares lesion characteristics between a second-generation focused electric field (FEF) catheter vs a standard irrigated catheter using RF energy in a beating heart model. We performed in vivo ablations using RF energy with the FEF ablation catheter tip (Focused Therapeutics) and an irrigated Blazer catheter (Boston Scientific) under identical power, duration, and irrigation rates. In addition, RF dosing at high power and duration was examined using the FEF catheter. Intracardiac echocardiography was used to evaluate steam pops and catheter tip angle relative to the tissue surface. Studies were terminal and lesion size was measured following 2,3,5-triphenyltetrazolium chloride staining. Ablations were performed in 6 swine (FEF, n = 31; control, n = 8). FEF ablation lesions (n = 7) were deeper (15.6 ± 2.6 mm vs 7.5 ± 1.9 mm; P < 0.001) and wider (18.4 ± 2.9 mm vs 12.6 ± 2.4 mm; P < 0.001) than lesions delivered with the control irrigated catheter (n = 8) under the same parameters. Thirty-two percent (n = 10 of 31) of lesions delivered from the left ventricle endocardial surface using the FEF catheter were transmural. No steam pops were observed with delivery of FEF lesions (n = 31). The angle of incidence did not significantly affect FEF lesion size. In this in vivo preclinical study, the FEF catheter, which provides focused energy delivery, resulted in significantly larger lesions than the irrigated control catheter without steam pops. Approximately one-third of ablations with the FEF catheter delivered from the endocardial left ventricular surface resulted in transmural lesions.

Prophylactic dialysis improves short-term clinical outcome in patients with non-dialysis-dependent chronic kidney disease undergoing cardiac surgery: a meta-analysis of randomized controlled trials.

BACKGROUND: Several studies have reported that prophylactic dialysis can reduce the mortality of non-dialysis-dependent chronic kidney disease (CKD) patients after cardiac surgery. However, the results of complications in these randomized controlled trials (RCTs) were not consistent. We aimed to perform a meta-analysis to systematically evaluate the effect of prophylactic dialysis in these non-dialysis-dependent CKD patients. METHODS: We systematically searched Medline, Embase, Cochrane's Library and other online sources for related RCTs. Effects of prophylactic dialysis on the incidence of 30 days' mortality and postoperative complications were analyzed. RESULTS: Four RCTs comprising 395 patients were included, all of them treated by coronary artery bypass grafting. Treatment of preoperative and intraoperative prophylactic dialysis significantly reduced the rate of 30-day all-cause mortality (risk ratio [RR]: 0.27, 95% confidence interval [CI], 0.13-0.58, P < 0.001, I2 = 0%) and the incidence of pulmonary complications (RR: 0.39, 95% CI, 0.20-0.77, P = 0.007, I2 = 0%), low cardiac output (RR: 0.29, 95% CI, 0.09-0.99, P = 0.05, I2 = 0%), and acute kidney injury (RR: 0.19, 95% CI: 0.07-0.52, P = 0.001, I2 = 0%). However, there were no statistically significant differences between the dialysis group and the control group in gastrointestinal bleeding, sepsis or multiple organ failure, wound infection, arrhythmia, transient neurologic deficit, stroke and re-exploration for bleeding. CONCLUSION: Prophylactic dialysis can improve the 30-day clinical outcomes of non-dialysis-dependent CKD patients undergoing cardiac surgery, it was associated with the 30-day mortality benefit and led to a decrease in the incidence of pulmonary complications, as well as low cardiac output, and acute kidney injury.

Autopsy findings of left atrial appendage closure device.

We report an autopsy case of an 80-year-old woman who underwent left atrial appendage closure with a WATCHMAN (Boston Scientific, St. Paul, MN, USA) device. This is the first report of histologic assessment following left atrial appendage closure with a WATCHMAN device at 3 months. Gross and histopathological examinations revealed neoendocardial coverage of the WATCHMAN device. Partial endothelialization was verified by CD34 staining; however, it remains unclear when complete endothelialization is likely to occur.

Short- and long-term effects of a cardiac rehabilitation program in patients implanted with a left ventricular assist device.

The efficacy of cardiac rehabilitation in heart-failure patients who received a left-ventricular assist device (LVAD) instead of heart transplantation (HTx) is still unclear. This study aims to evaluate whether cardiac rehabilitation is beneficial in LVAD as HTx patients in the short term and whether its effects in LVAD patients persist over time. Twenty-five LVAD patients were evaluated by functional and psychological tests at admission (T0) and discharge (T1) of a 4-week inpatient structured rehabilitation program, and follow-ups 3 (T2), 6 (T3), and 12 months (T4) after discharge. Twenty-five matched HTx patients were also studied from T0 to T1 to compare the improvements in the six-minute walk test (6MWT). The quality-of-life scores substantially improved in LVAD patients and the 6MWT showed the same functional recovery as in HTx patients from T0 to T1. After T1, numerous LVAD patients withdrew from the study. However, the 6MWT outcome increased further from T1 to T3, with a positive trend during the follow-ups. Hemoglobin and the ventilatory performance increased, and the psychological perception of heart-failure symptoms and pain further improved at T2. In conclusion, exercise-based rehabilitation programs provide similar beneficial effects in LVAD and HTx patients, without deterioration in LVAD patients up to 12 months after discharge.

Ex Vivo Model of Ischemic Mitral Regurgitation and Analysis of Adjunctive Papillary Muscle Repair.

Ischemic mitral regurgitation (IMR) is particularly challenging to repair with lasting durability due to the complex valvular and subvalvular pathologies resulting from left ventricular dysfunction. Ex vivo simulation is uniquely suited to quantitatively analyze the repair biomechanics, but advancements are needed to model the nuanced IMR disease state. Here we present a novel IMR model featuring a dilation device with precise dilatation control that preserves annular elasticity to enable accurate ex vivo analysis of surgical repair. Coupled with augmented papillary muscle head positioning, the enhanced heart simulator system successfully modeled IMR pre- and post-surgical intervention and enabled the analysis of adjunctive subvalvular papillary muscle repair to alleviate regurgitation recurrence. The model resulted in an increase in regurgitant fraction: 11.6 ± 1.7% to 36.1 ± 4.4% (p < 0.001). Adjunctive papillary muscle head fusion was analyzed relative to a simple restrictive ring annuloplasty repair and, while both repairs successfully eliminated regurgitation initially, the addition of the adjunctive subvalvular repair reduced regurgitation recurrence: 30.4 ± 5.7% vs. 12.5 ± 2.6% (p = 0.002). Ultimately, this system demonstrates the success of adjunctive papillary muscle head fusion in repairing IMR as well as provides a platform to optimize surgical techniques for increased repair durability.

Synthetic Material Abdominal Swabs Reduce Activation of Platelets and Leukocytes Compared to Cotton Materials.

During surgical procedures, cotton abdominal swabs with their high absorptive capacity and malleability are used to retain organs and absorb blood or other body fluids. Such properties of the natural material cotton are advantageous for most operations, but in cardiopulmonary bypass (CPB) surgery, a high blood volume can accumulate in the thoracic cavity that is quickly retransfused via the heart-lung machine (HLM). This common practice is supposed to be safe due to the high anticoagulation. However, in vitro analyses showed that blood cells and plasma proteins were activated despite a high anticoagulation, which can propagate especially an inflammatory response in the patient. Thus, we investigated patients' blood during CPB surgery for inflammatory and coagulation-associated activation after contact to the HLM and either cotton or synthetic abdominal swabs. Contact with cotton significantly increased thrombocyte and neutrophil activation measured as ß-thromboglobulin and PMN-elastase secretion, respectively, compared to synthetic abdominal swabs. Both inflammatory cytokines, interleukin (IL) 1ß and IL6, were also significantly increased in the cotton over the synthetic patient group, while SDF-1α was significantly lower in the synthetic group. Our data show for the first time that cotton materials can activate platelets and leukocytes despite a high anticoagulation and that this activation is lower with synthetic materials. This additional activation due to the material on top of the activation exerted by the tissue contact that blood is exposed to during CPB surgery can propagate further reactions in patients after surgery, which poses a risk for this already vulnerable patient group.

Optimizing cerebral perfusion and hemodynamics during cardiopulmonary bypass through cannula design combining in silico, in vitro and in vivo input.

Cardiopulmonary bypass (CPB) is a standard technique for cardiac surgery, but comes with the risk of severe neurological complications (e.g. stroke) caused by embolisms and/or reduced cerebral perfusion. We report on an aortic cannula prototype design (optiCAN) with helical outflow and jet-splitting dispersion tip that could reduce the risk of embolic events and restores cerebral perfusion to 97.5% of physiological flow during CPB in vivo, whereas a commercial curved-tip cannula yields 74.6%. In further in vitro comparison, pressure loss and hemolysis parameters of optiCAN remain unaffected. Results are reproducibly confirmed in silico for an exemplary human aortic anatomy via computational fluid dynamics (CFD) simulations. Based on CFD simulations, we firstly show that optiCAN design improves aortic root washout, which reduces the risk of thromboembolism. Secondly, we identify regions of the aortic intima with increased risk of plaque release by correlating areas of enhanced plaque growth and high wall shear stresses (WSS). From this we propose another easy-to-manufacture cannula design (opti2CAN) that decreases areas burdened by high WSS, while preserving physiological cerebral flow and favorable hemodynamics. With this novel cannula design, we propose a cannulation option to reduce neurological complications and the prevalence of stroke in high-risk patients after CPB.

Trans-esophageal echocardiography guided closure of ventricular septal defect with 2 occluders from different incisions simultaneously: A case report.

INTRODUCTION: Ventricular septal defect (VSD) accounts for up to 40% of all congenital cardiac malformations. Transthoracic closure of VSDs has been well described in literature. In the current report, we described a procedure to successfully close a VSD with 2 occluders from different incisions simultaneously under the guidance of trans-esophageal echocardiography (TEE), to save the patient from undergoing another surgery. PATIENT CONCERNS: A 52-year-old man was referred to our clinic for repeating palpitations for 6 months without chest pain and polypnea after activity. DIAGNOSIS: The diagnosis of VSD was established due to the findings of a juxtatricuspid VSD with a left-to-right shunt at ventricular level and mild mitral regurgitation by TTE. INTERVENTIONS: A transcatheter VSD closure was firstly performed but failed to repair the VSD. After the failure of transcatheter VSD closure, the patient received transthoracic closure of VSD operated by a cardiac surgeon. The VSD was closed with 2 occluders from different incisions (median thoracic skin incision and subxiphoid incision) simultaneously under the TEE guidance. OUTCOMES: The patient was extubated in intensive care unit and was discharged 4 days after the operation. During the follow up, there were no significant clinical nor laboratory side-effects of the procedure found as compared to the patient's condition before the procedure. CONCLUSION: VSD can be closed with 2 occluders from different incisions simultaneously under the TEE guidance to save the patient from undergoing repeated surgeries. Meanwhile, TEE plays a significant role in cardiac surgery.

[Left Atrial Appendage Closure - step by step]. / Vorhofohrverschluss ­ Schritt für Schritt.

Thrombus formation due to atrial fibrillation is the most common cause of embolic stroke. Anticoagulation offers an effective prophylaxis. However, anticoagulation in turn has an inherent increased risk of bleeding. Patients with non-valvular atrial fibrillation who have contraindications for anticoagulation may profit from a closure of the left atrial appendage. The most commonly and best studied devices for this are the WATCHMAN™ and the AMPLATZER Amulet™ Occluders.In this How-To article, the aim is to offer a general overview of the indications, contraindications and complications as well as the implantation and postoperative management of patients receiving LAA closure by example of the WATCHMAN FLX™ Occluder.

Transcatheter mitral valve repair: an overview of current and future devices.

The field of transcatheter mitral valve repair (TMVr) for mitral regurgitation (MR) is rapidly evolving. Besides the well-established transcatheter mitral edge-to-edge repair approach, there is also growing evidence for therapeutic strategies targeting the mitral annulus and mitral valve chordae. A patient-tailored approach, careful patient selection and an experienced interventional team is crucial in order to optimise procedural and clinical outcomes. With further data from ongoing clinical trials to be expected, consensus in the Heart Team is needed to address these complexities and determine the most appropriate TMVr therapy, either single or combined, for patients with severe MR.

Atrio-aortic erosion caused by Amplatzer Atrial Septal Occluder - a case report.

BACKGROUND: In specialized centers, percutaneous closure using specific occluders is the first-choice treatment in atrial septal defects (ASD). Late complications after this intervention, such as erosion of the aorta or the atria, are rare and have not been sufficiently approached and dealt with in literature. In our clinic we have been faced with the problematic situation of diagnosing and treating such cases. That is why, we have decided to share our experience with other colleagues. CASE PRESENTATION: We present two cases of severe late complications after percutaneous closure of atrial septal defects (ASD). In both cases, the atrial septal occluder (Amplatzer™ Atrial Septal Occluder Device, Abbott, Chicago USA) caused the erosion between the left atrium and the aortic root. The atrio-aortic erosion led to acute cardiac tamponade with upper venous congestion and shock. As the bleeding source remained undetectable for any imaging tools, a diagnostical sternotomy remained the only solution. The cause of the acute bleeding was discovered to be the erosion between the left atrium and the aortic root. The treatment consisted in the removal of the occluder, direct suturing of the perforated areas and the surgical closure of the remaining ASD. The patients fully recovered within the nine to fourteen days' hospital stay. Six months after surgery both patients were well and able to recover their daily routine. CONCLUSIONS: The atrio-aortic erosion after percutaneous closure of atrial septal defects is a surgical emergency. The more so, since it can be complicated by the absence of specific symptoms. A key-element in the diagnosis of this rare pathology remains the medical history of the patient, which the surgeon has to consider thoroughly and launch the diagnostic sternotomy without delay.

Outcomes of pulmonary valve leaflet augmentation for transannular repair of tetralogy of Fallot.

OBJECTIVE: To evaluate the midterm results of pulmonary valve leaflet augmentation in transannular repair of tetralogy of Fallot (TOF). METHODS: From 2007 to 2019, 131 patients underwent a transannular repair with pulmonary leaflet augmentation for TOF (n = 120) and double outlet right ventricle with pulmonary stenosis (n = 11). Patch material was expanded polytetrafluoroethylene (n = 76), glutaraldehyde-treated autologous pericardium (n = 47) and bovine pericardium (n = 8). RESULTS: Median age at repair was 8.9 months (interquartile range, 5.4-14.8). There was no operative mortality. Median follow-up was 6.25 years (interquartile range, 2.77-7.75). Freedom from severe pulmonary regurgitation (PR) was 85% (95% confidence interval [CI], 77%-90%) and 76% (95% CI, 66%-83%) at 1 and 5 years, respectively. Freedom from moderate or greater PR was 69% (95% CI, 60%-76%) and 30% (95% CI, 21%-39%) at 5 and 10 years, respectively. Three patients required pulmonary valve replacement for PR. Nine patients required pulmonary balloon valvuloplasty. Freedom from intervention for pulmonary valve stenosis was 98% (95% CI, 93%-99%) and 94% (95% CI, 87%-97%) at 1 and 5 years, respectively. One patient with severe PR had an indexed right ventricular volume >160 mL/m2. Use of expanded polytetrafluoroethylene resulted in a greater freedom from moderate or greater PR (log-rank test P < .001; Cox regression hazard ratio, 0.40; 95% CI, 0.25-0.63; P < .001). CONCLUSIONS: At midterm follow-up of transannular repair with pulmonary valve leaflet augmentation, severe PR occurs in less than 50% of patients. The expanded polytetrafluoroethylene patch performs better than pericardium.

A perfusable, multifunctional epicardial device improves cardiac function and tissue repair.

Despite advances in technologies for cardiac repair after myocardial infarction (MI), new integrated therapeutic approaches still need to be developed. In this study, we designed a perfusable, multifunctional epicardial device (PerMed) consisting of a biodegradable elastic patch (BEP), permeable hierarchical microchannel networks (PHMs) and a system to enable delivery of therapeutic agents from a subcutaneously implanted pump. After its implantation into the epicardium, the BEP is designed to provide mechanical cues for ventricular remodeling, and the PHMs are designed to facilitate angiogenesis and allow for infiltration of reparative cells. In a rat model of MI, implantation of the PerMed improved ventricular function. When connected to a pump, the PerMed enabled targeted, sustained and stable release of platelet-derived growth factor-BB, amplifying the efficacy of cardiac repair as compared to the device without a pump. We also demonstrated the feasibility of minimally invasive surgical PerMed implantation in pigs, demonstrating its promise for clinical translation to treat heart disease.

A new device to treat mitral valve regurgitation: a proof of concept in bench test study.

Mitral valve repair is typically performed by implanting a ring-like device at the valve annulus to reshape the annulus and to improve leaflet coaptation. In most cases, some additional procedures are needed, including leaflet resection and artificial chordae implantation. However, artificial chordae implantation could be technically challenging and postoperative left ventricular remodeling could increase the risk of recurrent mitral regurgitation. We propose an innovative annular device made of chromo-cobalt, finalized not only to reshape the annulus but also to enable anchoring of leaflets to a fixed intraventricular structure. Durability evaluation of the device was tested by applying eight radial force vectors equally spaced along the ring and related fatigue analysis. To evaluate the efficacy of the mitral valvuloplasty using the tested ring, the device was implanted in five adult swine hearts. Functional analysis of the ring was performed by measuring left ventricular pressure and fluid volume loss, following implantation in normal and dysfunctional mitral valve leaflets. Both fatigue and functional analysis showed satisfactory and promising results in terms of durability and efficacy of mitral valve repair. Because of its favorable durability and functional characteristics this device appears promising and provides good results in terms of valve competence, thus avoiding both manipulations of papillary muscles and interference in left ventricular hemodynamics. However, an in vivo test is mandatory to fully understand the impact of the device on subvalvular apparatus.

A systematic review of the quality of cardiovascular surgery studies that extracted data from the MAUDE database.

OBJECTIVE: To investigate opportunities and limitations of using the Manufacturer and User Facility Device Experience (MAUDE) database for cardiovascular surgery research, we analyzed the quality of studies having ever used MAUDE, in the field of cardiovascular surgery. METHODS: We systematically searched the Cochrane Library, PubMed, EMBASE, and Google Scholar for randomized and nonrandomized studies, from inception to July 2019. Two authors evaluated the quality of the retrieved observational studies, according to the National Institutes of Health quality assessment tool for either case series or cross-sectional studies. These tools quantify the quality of case series and cohorts/cross-sectional studies, respectively, with nine and 14 queries. RESULTS: Fifty-eight studies were included in the final qualitative review. Of 58 identified studies, 32 were case series, 8 were abstracts of case series, and 13 were reviews or case discussion with an included series from MAUDE. Also, five articles were cross-sectional studies. Of the 32 formal case series, 26 (81%) were found to have poor quality. The most common reasons for a poor quality designation included a lack of consecutive participants, undetermined comparability of participants, and undetermined follow-up adequacy. Only one out of five cross-sectional studies had fair quality; four others were evaluated as poor quality studies. CONCLUSIONS: Cardiovascular surgery studies using the MAUDE database, whether case series or cross-sectional design, are mostly of poor quality. Their low quality is partly caused by poor study design, but mainly by intrinsic limitations to the MAUDE database: cases recruited are not consecutive; patient characteristics are not detailed enough to allow a meaningful comparison of patient characteristics between different patient entries; outcome measures are unclear; there is a limited follow-up; and time-to-event data are lacking. We conclude that the quality of cardiovascular surgery publications that rely on data from MAUDE could be improved if investigators were to extract all relevant data points from MAUDE entries, then apply standard quality assessment tools in compiling and reporting the data. MAUDE might be improved if it used medical case report standards during the process of reporting and indexing adverse events. To calculate the incidence rate of any adverse event, all event-free cases, as well as all adverse events in patients using a device, are required. Neither of these two variables is available in the MAUDE at the time of writing.

Endothelium-Mimicking Nanomatrix Coating to Enhance Endothelialization after Left Atrial Appendage Closure Device Implantation.

Blood clots (90%) originate from the left atrial appendage (LAA) in non-valvular atrial fibrillation patients and are a major cause of embolic stroke. Long-term anticoagulation therapy has been used to prevent thrombus formation, but its use is limited in patients at a high risk for bleeding complications. Thus, left atrial appendage closure (LAAC) devices for LAA occlusion are well-established as an alternative to the anticoagulation therapy. However, the anticoagulation therapy is still required for at least 45 days post-implantation to bridge the time until complete LAA occlusion by neoendocardium coverage of the device. In this study, we applied an endothelium-mimicking nanomatrix to the LAAC device membrane for delivery of nitric oxide (NO) to enhance endothelialization, with the goal of possibly being able to reduce the duration of the anticoagulation therapy. The nanomatrix was uniformly coated on the LAAC device membranes and provided sustained release of NO for up to 1 month in vitro. In addition, the nanomatrix coating promoted endothelial cell proliferation and reduced platelet adhesion compared to the uncoated device membranes in vitro. The nanomatrix-coated and uncoated LAAC devices were then deployed in a canine LAA model for 22 days as a pilot study. All LAAC devices were not completely covered by neoendocardium 22 days post-implantation. However, histology image analysis showed that the nanomatrix-coated LAAC device had thicker neoendocardium coverage compared to the uncoated device. Therefore, our in vitro and in vivo results indicate that the nanomatrix coating has the potential to enhance endothelialization on the LAAC device membrane, which could improve patient outcomes by shortening the need for extended anticoagulation treatment.

Nitric oxide added to the sweep gas of the oxygenator during cardiopulmonary bypass in infants: A pilot randomized controlled trial.

Our objective was to assess the effect of nitric oxide added to the sweep gas of the oxygenator during cardiopulmonary bypass (CPB) in infants on platelet count, platelet function, clinical outcomes, and safety. A randomized, double-blinded, placebo-controlled clinical trial in infants less than a year of age undergoing cardiac surgery requiring CPB was undertaken. Nitric oxide at a dose of 20 ppm was added to the sweep gas in the treatment group. Blood was collected at baseline and prior to separation from CPB to measure platelet count and function as determined by responsiveness to specific agonists. Clinical outcomes were observed through hospital discharge. Methemoglobin levels were measured preoperatively, at the conclusion of CPB, and upon admission to the ICU. Forty patients consented and were randomized in the trial. Eighteen patients were randomized to the treatment group and 22 were included in the placebo group. The groups were similar in terms of age, weight, gender, and surgical complexity. No significant differences were found in measures of platelet count, platelet response to agonist, or clinical outcomes. Patients in the treatment group had higher methemoglobin levels after receiving nitric oxide, but no levels approached toxicity (maximum 2.4%). Nitric oxide added to the sweep gas of the oxygenator during CPB in infants did not have an appreciable effect on the preservation of platelet count, platelet responsiveness to agonist, or clinical outcomes. Methemoglobin levels were increased after receiving nitric oxide but were far below a toxic level of 15%.

Transseptal access through atrial flow regulator device during ventricular tachycardia ablation.

Novel interventional therapies for heart failure patients are emerging like atrial flow regulator (AFR). Our case showed that endocardial ventricular tachycardia (VT) ablation could be performed safely by passing through the AFR device lumen without additional transseptal puncture in these patients.