Cardiac surgery elicits pericardial inflammatory responses that are distinct compared with postcardiopulmonary bypass systemic inflammation.

Objectives: Cardiac surgery using cardiopulmonary bypass contributes to a robust systemic inflammatory process. Local intrapericardial postsurgical inflammation is believed to trigger important clinical implications, such as postoperative atrial fibrillation and postsurgical intrathoracic adhesions. Immune mediators in the pericardial space may underlie such complications. Methods: In this prospective pilot clinical study, 12 patients undergoing isolated coronary artery bypass graft surgery were enrolled. Native pericardial fluid and venous blood samples (baseline) were collected immediately after pericardiotomy. Postoperative pericardial fluid and venous blood samples were collected 48-hours after cardiopulmonary bypass and compared with baseline. Flow cytometry determined proportions of specific immune cells, whereas multiplex analysis probed for inflammatory mediators. Results: Neutrophils are the predominant cells in both the pericardial space and peripheral blood postoperatively. There are significantly more CD163lo macrophages in blood compared with pericardial effluent after surgery. Although there are significantly more CD163hi macrophages in native pericardial fluid compared with baseline blood, after surgery there are significantly fewer of these cells present in the pericardial space compared with blood. Postoperatively, concentration of interleukin receptor antagonist 6, and interleukin 8 were significantly higher in the pericardial space compared with blood. After surgery, compared with blood, the pericardial space has a significantly higher concentration of matrix metalloproteinase 3, matrix metalloproteinase 8, and matrix metalloproteinase 9. The same trend was observed with transformational growth factor ß. Conclusions: Cardiac surgery elicits an inflammatory response in the pericardial space, which differs from systemic inflammatory responses. Future work should determine whether or not this distinct local inflammatory response contributes to postsurgical complications and could be modified to influence clinical outcomes.

Sternum-Sparing Left Ventricular Assist Device Insertion Reduces Perioperative Transfusions and Blood Loss: A Single-Centre Canadian Experience.

Background: Left ventricular assist devices (LVADs) improve survival and quality of life, as either destination therapy or a bridge to transplantation. Although less-invasive hemisternotomy approaches for LVAD implantation are well studied, only a paucity of data is available in the literature on sternum-sparing bilateral minithoracotomy (BMT). Our centre has one of Canada's most extensive experiences with the BMT approach. Herein, we compared LVAD implantation via BMT with patients who received full median sternotomy or hemisternotomy. Methods: A single-centre retrospective review of data from Foothills Medical Centre (Calgary, Canada) was performed. Patients underwent LVAD insertion from 2012 to 2019, receiving either BMT (n = 11) or sternotomy (full median sternotomy or upper hemisternotomy with left minithoracotomy; n = 38). Intraoperative and early postoperative outcomes were assessed. Results: Patients who received BMT had significantly fewer transfusions of red blood cells, fresh frozen plasma, and platelets. The BMT group had lower chest-tube output in the first 12 hours. No significant differences occurred in ventilation time, intensive care unit length of stay, mortality, stroke, or reoperation for bleeding. Conclusions: Outcomes suggest that sternum-sparing LVAD implantation is a feasible alternative to sternotomy, leading to less postoperative blood loss and transfusion in the early postoperative period. Less transfusion is particularly valuable in this patient population, to reduce antigen-related sensitization prior to transplantation. Additional study is needed to assess potential benefits related to right heart function, postoperative mobility, and re-entry for transplantation.

Introduction: Les dispositifs d'assistance ventriculaire gauche (DAVG) contribuent à améliorer la survie et la qualité de vie, soit en traitement définitif ou en attente d'une transplantation. Bien que des approches d'hémisternotomie moins invasives lors de l'implantation d'un DAVG font l'objet d'un bon nombre d'études, seules de rares données sont disponibles dans la littérature sur la minithoracotomie bilatérale (MTB) sans ouverture du sternum. Notre centre possède l'une des expériences les plus approfondies au Canada de l'approche par MTB. Dans le présent article, nous avons comparé l'implantation du DAVG par MTB chez les patients qui avaient subi une sternotomie médiane complète ou une hémisternotomie. Méthodes: Nous avons réalisé une revue rétrospective unicentrique des données du Foothills Medical Centre (Calgary, Canada). Les patients avaient subi l'insertion d'un DAVG de 2012 à 2019, soit par MTB (n = 11) ou par sternotomie (sternotomie médiane complète ou hémisternotomie supérieure associée à une minithoracotomie gauche ; n = 38). Nous avons évalué les résultats peropératoires et postopératoires précoces. Résultats: Les patients qui avaient subi une MTB avaient eu significativement moins de transfusions de globules rouges, de plasma frais congelé et de plaquettes. Le groupe de MTB avait un plus faible débit du drain thoracique dans les 12 premières heures. Aucune différence significative dans la durée de ventilation, la durée du séjour aux soins intensifs, la mortalité, l'accident vasculaire cérébral ou la réopération en raison d'un saignement n'a été observée. Conclusions: Les résultats montrent que l'implantation de DAVG sans ouverture du sternum est une alternative à la sternotomie, qui entraîne moins de pertes de sang postopératoires et de transfusions en phase postopératoire précoce. Un moins grand nombre de transfusions est particulièrement important au sein de cette population de patients afin de réduire la sensibilisation aux antigènes avant la transplantation. D'autres études sont nécessaires pour évaluer les avantages potentiels liés à la fonction du cœur droit, la mobilité après l'opération et la réadmission pour une transplantation.

Comprehensive characterization of the postoperative pericardial inflammatory response: Potential implications for clinical outcomes.

Objective: There is a paucity of data on the inflammatory response that takes place in the pericardial space after cardiac surgery. This study provides a comprehensive assessment of the local postoperative inflammatory response. Methods: Forty-three patients underwent cardiotomy, where native pericardial fluid was aspirated and compared with postoperative pericardial effluent collected at 4, 24, and 48 hours' postcardiopulmonary bypass. Flow cytometry was used to define the levels and proportions of specific immune cells. Samples were also probed for concentrations of inflammatory cytokines, matrix metalloproteinases (MMPs), and tissue inhibitors of metalloproteinases (TIMPs). Results: Preoperatively, the pericardial space mainly contains macrophages and T cells. However, the postsurgical pericardial space was populated predominately by neutrophils, which constituted almost 80% of immune cells present, and peaked at 24 hours. When surgical approaches were compared, minimally invasive surgery was associated with fewer neutrophils in the pericardial space at 4 hours' postsurgery. Analysis of the intrapericardial concentrations of inflammatory mediators showed interleukin-6, MMP-9, and TIMP-1 to be highest postsurgery. Over time, MMP-9 concentrations decreased significantly, whereas TIMP-1 levels increased, resulting in a significant reduction of the ratio of MMP:TIMP after surgery, suggesting that active inflammatory processes may influence extracellular matrix remodeling. Conclusions: These results show that cardiac surgery elicits profound alterations in the immune cell profile in the pericardial space. Defining the cellular and molecular mediators that drive pericardial-specific postoperative inflammatory processes may allow for targeted therapies to reduce immune-mediated complications.

Right anterior mini thoracotomy approach for isolated aortic valve replacement: Early outcomes at a Canadian center.

OBJECTIVE: The goal of this manuscript was to report the clinical outcomes of the initial series of 100 consecutive Right Anterior Mini Thoracotomy (RAMT) aortic valve replacement (AVR) implantations at a Canadian Center. METHODS: This retrospective study reported the clinical outcomes of the first 100 patients who underwent the RAMT approach for isolated surgical AVR in Calgary, Canada, between 2016 and 2020. Primary outcomes were death within 30 days of surgery and disabling stroke. Secondary outcomes included surgical times, the need for permanent pacemaker (PPM), incidence of postoperative blood transfusion in the intensive care unit (ICU), postsurgical atrial fibrillation (AF), length of ICU/hospital stay, postsurgical AF, residual paravalvular leak (PVL), postoperative transvalvular gradient, need for postsurgical intravenous opioids, duration of invasive ventilation in the ICU, and chest tube output in the first 12 h postsurgery. RESULTS: In this study, 54 patients were male, and the average age of the cohort was 72 years. Mortality within 30 days of surgery was 1% with no disabling postoperative strokes. Mean cardiopulmonary bypass and cross clamp was 84 and 55 min, respectively. PPM rate was 3%, incidence of blood transfusion in the ICU was 4%, and the rate of postoperative AF was 23%. Median length of ICU and hospital stay was 1 and 5 days, respectively. Rate of mild or greater residual PVL was 3%, while the average residual transvalvular mean gradient was 8.5 mmHg. CONCLUSION: The sternum-sparing RAMT approach can be safely integrated into surgical practice as a minimally invasive alternative for isolated AVR, and can reduce postoperative bleeding and narcotic requirements.

Left ventricular assist devices: A comprehensive review of major clinical trials, devices, and future directions.

Heart failure is an increasingly prevalent medical condition associated with significant morbidity and mortality. In spite of optimal medical therapy, a large number of patients continue to deteriorate clinically and could potentially benefit from advanced therapies. While cardiac transplantation is an established therapy for end-stage heart failure, there are a limited number of donor hearts, and many patients may not be candidates. Over the past two decades, mechanical circulatory support and left ventricular assist devices (LVAD) have altered the heart failure management landscape. Herein we review the indications for LVAD implantation and how they have changed over time. We will also outline major technological evolutions in LVADs and summarize the landmark clinical trials pertaining to them. We also highlight the adverse events associated with LVADs and assess the limitations of the existing literature. Finally, we look ahead to the future of LVAD therapy for patients with advanced heart failure.

LVAD with concomitant rapid deployment valve implantation - a case report.

BACKGROUND: Aortic valve insufficiency can have significant hemodynamic consequences for patients with left ventricular assist devices. A circulation loop can limit systemic blood flow and increase left ventricular filling pressure. CASE PRESENTATION: A 64-year-old male with non-ischemic dilated cardiomyopathy underwent Heartware™ HVAD left ventricular assist device implantation with successful concomitant aortic valve replacement with an Edwards Intuity rapid deployment prosthetic valve. CONCLUSIONS: The use of this rapid deployment valve may have benefits over other techniques including shorter cross clamp times during surgery, intermediate-long term durability, and preservation of aortic valve opening to allow for potential ventricular recovery. The Intuity rapid deployment valve should thus be considered a viable and suitable option for aortic insufficiency intervention during LVAD implantation.

An ex-vivo quantitative assessment to determine the optimal aortotomy closure technique.

BACKGROUND: After performing an aortotomy, there are a variety of techniques utilized for suture closure. There is no published data comparing the efficacy of various suture techniques. The goal of this study is to provide an ex-vivo quantitative assessment of resistance to leakage and dehiscence for three aortotomy closure techniques. MATERIALS AND METHODS: An ex-vivo model was developed utilizing explanted porcine aorta. Aortotomies were closed using one of three techniques: 1) single layer baseball stitch 2) double layer baseball stitch 3) horizontal mattress stitch with a top layer baseball stitch. The aorta was pressurized with saline using an apparatus which captured all leaked fluid. The intra-aortic pressure was adjusted over 8 increments from 110 to 375 mmHg. Leakage rates were determined at each pressure level. Ten aortotomies were performed for each technique, resulting in 240 calculated leakage rates. RESULTS: At all pressures, the horizontal mattress group was measured to have significantly less leakage when compared to single or double layer baseball stitch closures (p < 0.005). There was a trend towards a lower leakage rate in the double layer baseball compared to the single layer baseball stitch. However, this difference is statistically significant only at 300 and 335 mmHg. There were no instances of rupture. CONCLUSION: This study provides the first quantitative comparison of three commonly used aortotomy closure techniques. The running horizontal mattress stitch combined with a baseball stitch provides the greatest resistance to leakage at all pressures. This technique may be superior in clinical scenarios with challenging hemostasis.