PubMed Posts

Immunohistochemistry (IHC) and immunofluorescence (IF) are crucial techniques for studying cardiac physiology and disease. The accuracy of these techniques is dependent on various aspects of sample preparation and processing. However, standardised protocols for sample preparation of tissues, particularly for fresh-frozen human left ventricle (LV) tissue, have yet to be established and could potentially lead to differences in staining and interpretation. Thus, this study aimed to optimise the reproducibility and quality of IF staining in fresh-frozen human LV tissue by systematically investigating crucial aspects of the sample preparation process. To achieve this, we subjected fresh-frozen human LV tissue to different fixation protocols, primary antibody incubation temperatures, antibody penetration reagents, and fluorescent probes. We found that neutral buffered formalin fixation reduced image artefacts and improved antibody specificity compared to both methanol and acetone fixation. Additionally, incubating primary antibodies at 37°C for 3 h improved fluorescence intensity compared to the commonly practised 4°C overnight incubation. Furthermore, we found that DeepLabel, an antibody penetration reagent, and smaller probes, such as fragmented antibodies and Affimers, improved the visualisation depth of cardiac structures. DeepLabel also improved antibody penetration in CUBIC cleared thick LV tissue fragments. Thus, our data underscores the importance of standardised protocols in IF staining and provides various means of improving staining quality. In addition to contributing to cardiac research by providing methodologies for IF, the findings and processes presented herein also establish a framework by which staining of other tissues may be optimised.

Background: We aimed to assess the impact of complex mitral valve disease and patient risk profile on operative outcomes in the large cohort of the Mini-Mitral International Registry.

Methods: Patients were assigned to categories of complex degenerative mitral valve regurgitation (DMR; bileaflet or anterior mitral leaflet prolapse/flail) and simple DMR (posterior mitral leaflet prolapse/flail). Subgroup analyses was performed in low-risk (EuroSCORE II <8%) and high-risk (EuroSCORE II >8%) cohorts. A logistic regression model was applied to investigate the impact of valve anatomy and patient risk factors on valve repair rate and operative risk.

Results: The study cohort consisted of 4524 patients with DMR (complex DMR, 1296; simple DMR, 3228). Valve repair rate was 87.3% and 91% in complex DMR and simple DMR, respectively. Predictors of valve replacement were anterior leaflet prolapse/flail, bileaflet flail, female sex, age, and reoperation, whereas Barlow disease was protective. Clinical results were comparable between complex DMR and simple DMR. On subgroup analyses, high-risk patients showed less satisfactory outcomes with respect to both the valve repair and operative mortality rates.

Conclusions: Our findings suggest that complex DMR can be satisfactorily addressed by minimally invasive techniques. However, whereas complex disease was associated with low operative risk, anterior leaflet lesions and bileaflet flail remain negative predictors of successful valve repair. Conversely, valve repair rate was less satisfactory in high-risk patients, regardless of DMR complexity.

Intraoperative fluorescence imaging using indocyanine green (ICG) is an innovative and safe tool in minimally invasive thoracic surgery. It provides real-time imaging capabilities that can enhance surgical precision. We describe several clinical uses of ICG including intersegmental plane identification, thoracic duct injury localisation, anomalous systemic artery identification in pulmonary sequestration, phrenic nerve identification, and sentinel lymph node mapping. Successful visualisation of ICG was achieved to identify intra-thoracic anatomical structures and boundaries, allowing for safe and precise dissection.

The Impella CP is a percutaneously inserted temporary left ventricular assist device used in clinical practice and in translational research into cardiogenic shock, perioperative cardiac surgery, acute cardiac failure and mechanical circulatory support. Fluoroscopic guidance is usually used for insertion of an Impella, thus limiting insertion to within catheterization laboratories. Transthoracic, transoesophageal and intracardiac echocardiography have been reported to guide Impella CP implantation with identified specific limitations stemming from the surgical, anatomical and equipment factors. We conducted translational prospective descriptive feasibility investigation as a part of two other hemodynamic Impella studies. It showed the successful application of epicardial echocardiographic scanning for implantation of Impella CP devices in ovine models, from which details of the technique and identified pitfalls are described with practical solutions for future investigators and clinicians. Many described findings are relevant to any other echocardiographic techniques when adequate imaging of the Impella and relevant anatomical structures is achievable.

Introduction: Although cardiovascular surgery societies in Europe and the USA constantly strive for the exchange of knowledge and best practices in coronary artery bypass grafting (CABG), the available evidence on whether such efforts result in similar patient outcomes is limited. Therefore, in the present analysis, we sought to compare patient profiles and overall survival outcomes for up to 3 years between large European and US patient cohorts who underwent isolated CABG.

Methods: Patients from the European DuraGraft Registry (n = 2,522) who underwent isolated CABG at 45 sites in eight different European countries between 2016 and 2019 were compared to randomly selected patients from the US STS database who were operated during the same period (n = 294,725). Free conduits (venous and arterial grafts) from the DuraGraft Registry patients were intraoperatively stored in DuraGraft, an endothelial damage inhibitor, before anastomosis, whereas grafts from the STS Registry patients in standard-of-care solutions (e.g., saline). Propensity score matching (PSM) models were used to account for differences in patient baseline and surgical characteristics, using a primary PSM with 35 variables (2,400 patients matched) and a secondary PSM with 25 variables (2,522 patients matched, sensitivity analysis). The overall survival for up to 3 years after CABG was assessed as the primary endpoint.

Results: The comparison of patient profiles showed significant differences between the European and US cohorts. The European patients had more left main disease, underwent more off-pump CABG, and received more arterial grafts together with more complete arterial grafting procedures. In contrast, the US patients received more distal anastomoses with more saphenous vein grafts (SVGs) that were mainly harvested endoscopically. Such differences, however, were well balanced after PSM for the mortality comparison. Mortality comparison at 30 days, 12 months, and 24 months between the European and US patients was 2.38% vs. 1.96%, 4.32% vs. 4.79%, and 5.38% vs. 6.96%, respectively. At 36 months, the mortality was significantly lower in the European patients than that of their US counterparts (7.37% vs. 9.65%; p-value = 0.016). The estimated hazard ratio (HR) was 1.29 (95% CI 1.05-1.59).

Conclusion: This large-scale transatlantic comparative analysis shows that there are some significant differences in patient profiles between large cohorts of European and US patients. These differences were adjusted by using PSM for the mortality analysis. No significant difference in mortality was detected between groups through 2 years, but survival was significantly better in the European DuraGraft Registry patients at 3 years post-CABG.

Objectives: This study aimed to analyse the impact of preoperative septic cerebral embolism on early and late postoperative outcomes in patients with infective endocarditis undergoing valve surgery.

Methods: Retrospective multicentric study based on the Clinical Multicentric Project for Analysis of Infective Endocarditis in Germany (CAMPAIGN) registry comprising patients with infective endocarditis who underwent valve surgery between 1994 and 2018 at 6 German centres. Patients were divided into 2 groups for statistical comparison according to the presence or absence of preoperative septic cerebral embolism. Propensity score matching was performed for adjusted comparisons of postoperative outcomes. Primary outcomes were 30-day mortality and estimated 5-year survival.

Results: A total of 4917 patients were included in the analysis, 3909 (79.5%) patients without and 1008 (20.5%) patients with preoperative septic cerebral embolism. Patients with preoperative septic cerebral embolism had more baseline comorbidities. Mitral valve endocarditis (44.1% vs 33.0% P < 0.001), large vegetations >10 mm (43.1% vs 30.0%, P < 0.001), and Staphylococcus species infection (42.3% vs 21.3%, P < 0.001) were more frequent in the cerebral embolism group. Among patients with preoperative cerebral embolism, 286 (28.4%) patients had no stroke signs (silent stroke). After matching (1008 matched pairs), there was no statistically significant difference in 30-day mortality (20.1% vs 22.8%; P = 0.14) and 5-year survival (47.8% vs 49.1%; stratified log-rank P = 0.77) in patients with and without preoperative cerebral embolism, respectively.

Conclusions: Preoperative septic cerebral embolism in patients with infective endocarditis requiring valve surgery does not negatively affect early or late mortality; therefore, it should not play a major role in deciding if surgery is to be performed.

Objectives: Sex-related differences play a role in cardiovascular disease-related outcomes. There is, however, a knowledge gap regarding sex-specific differences in patients with infective endocarditis (IE)-requiring surgical treatment. This study aims to analyse sex-related differences in the clinical presentation, treatment and clinical outcomes of patients with IE-requiring surgical treatment from the multicentric Germany-wide CAMPAIGN registry.

Methods: Patients with IE who underwent cardiac surgery between 1994 and 2018 at six German centres were retrospectively analysed. Outcomes were compared based on patients’ sex. Primary outcomes were 30-day mortality and mid-term survival.

Results: A total of 4917 patients were included in the analysis (1364 female [27.7%] and 3553 male [72.3%]). Female patients presented with more comorbidities and higher surgical risk (EuroScore II 12.0% vs 10.0%, P < 0.001). The early postoperative course of female patients was characterized by longer ventilation times (20.0 h vs 16.0 h; P = 0.004), longer intensive care unit stay (4.0 days vs 3.0 days; P < 0.001), and more frequent new-onset dialysis (265 [20.3%] vs 549 [16.3%]; P = 0.001). The 30-day mortality was 13.8% and 15.5% in female and male patients, respectively (P = 0.06). The estimated mid-term survival was significantly higher amongst male patients (56.1% vs 45.4%; Log-rank P < 0.001). Female sex was an independent predictor of mid-term mortality (HR 1.2 [95% CI 1.0-1.4], P = 0.01).

Conclusions: Male patients more frequently undergo cardiac surgery for IE. However, female patients have a higher surgical risk profile and subsequently an increased early postoperative morbidity, but with similar 30-day mortality compared with male patients. The estimated mid-term survival is lower amongst female patients.

The development of small-diameter vascular grafts requires testing in large animal models before advancing to clinical trials. Vascular graft interposition implantation in sheep carotid arteries (CAs) is the most widely used model, but ovine CAs are prone to severe spasm following surgical manipulation, potentially impairing graft performance assessment. There is paucity in the literature on reducing sheep CA spasm using effective vasodilator therapeutic protocols. In this study, four healthy Merino cross White Suffolk wethers (1-2 years, 52.1 ± 0.8 kg) underwent CT angiography and CA graft surgery. CT angiography using iodinated contrast agent was performed with innominate artery access through the CA or ascending aortic arch access through the femoral artery. Sheep then underwent right CA sham surgery or left CA vascular graft implantation. A variety of vasodilators, including papaverine, sodium nitroprusside, verapamil, and their combination, were tested for preventing or treating CA spasms intraoperatively. Blood flow was reassessed immediately after CA surgery using CT angiography. The results showed that innominate artery access through the CA for CT angiography in sheep induced presurgical CA spasm with reduced arterial flow. Conversely, ascending aortic arch access through the femoral artery for CT angiography did not cause CA spasm and maintained arterial flow. During CA graft surgery, surgical trauma induced CA spasm, which was prevented by localized intra-arterial administration of vasodilators papaverine hydrochloride and verapamil before significant surgical manipulation.

Preclinical data have confirmed that human pluripotent stem cell-derived cardiomyocytes (PSC-CMs) can remuscularize the injured or diseased heart, with several clinical trials now in planning or recruitment stages. However, because ventricular arrhythmias represent a complication following engraftment of intramyocardially injected PSC-CMs, it is necessary to provide treatment strategies to control or prevent engraftment arrhythmias (EAs). Here, we show in a porcine model of myocardial infarction and PSC-CM transplantation that EAs are mechanistically linked to cellular heterogeneity in the input PSC-CM and resultant graft. Specifically, we identify atrial and pacemaker-like cardiomyocytes as culprit arrhythmogenic subpopulations. Two unique surface marker signatures, signal regulatory protein α (SIRPA)⁺CD90^–CD200⁺ and SIRPA⁺CD90^–CD200^–, identify arrhythmogenic and non-arrhythmogenic cardiomyocytes, respectively. Our data suggest that modifications to current PSC-CM-production and/or PSC-CM-selection protocols could potentially prevent EAs. We further show that pharmacologic and interventional anti-arrhythmic strategies can control and potentially abolish these arrhythmias.

Background: Despite the well-documented safety and feasibility of robotic coronary artery bypass grafting (CABG), widespread adoption of this approach remains limited by its steep learning curve, high procedural costs and paucity of data on longer-term efficacy. This current meta-analysis aims to provide a systematic overview of the outcomes of robot-assisted CABG, with a focus on long term graft patency and freedom from major adverse cardiac and cerebrovascular events (MACCE).

Methods: A systematic literature search of three electronic databases was conducted for studies reporting outcomes of robotic-assisted CABG, and were grouped based on whether patients underwent robot-assisted minimally invasive direct coronary artery bypass (RA-MIDCAB), totally endoscopic coronary artery bypass (TECAB) or were mixed. Perioperative and mid-to-long term results from included studies were pooled using meta-analysis of proportion or means in a random effects model.

Results: In the quantitative analysis, thirty-nine eligible studies included 6,152 patients who underwent RA-MIDCAB, 1,729 patients who underwent TECAB and 21,642 patients who underwent either form of robot-assisted CABG. A high level of heterogeneity was observed amongst baseline characteristics. Perioperative mortality and complication rates were low. Conversion rate to full sternotomy overall was less than 3.2% [95% confidence interval (CI): 2.1-5.2%, I²=39%]. At a mean follow-up duration of 5.2 years, overall graft patency was 96% for both RA-MIDCAB and TECAB, and freedom from major adverse cardiac events (MACE) or MACCE was 83.2% (95% CI: 72.0-90.4%; I²=90%) for RA-MIDCAB and 91.6% (95% CI: 86.6-94.9%; I²=76%) for TECAB.

Conclusions: Robot-assisted CABG is observed to have acceptable perioperative and mid-to-long term outcomes with promising overall graft patency.