Longitudinal cardiac dimensions in patients undergoing LVAD implantation.

BACKGROUND: In conventional left ventricular assist devices (LVAD), a separate outflow graft is sutured to the ascending aorta. Novel device designs may include a transventricular outflow cannula crossing the aortic valve (AV). While transversal ventricular dimensions are well investigated in patients with severe heart failure, little is known about the longitudinal dimensions. These dimensions are, however, particularly critical for the design and development of mechanical circulatory support (MCS) devices with transaortic outflow cannula. METHODS: In an explorative retrospective cohort study at the University Medical Center Freiburg, Germany, the longitudinal cardiac dimensions of patients undergoing computed tomography angiography (CTA) before and, if available, after LVAD implantation were analyzed. Among others, the following dimensions were assessed: (a) apex to AV, (b) apex to mitral valve, (c) AV to sinotubular junction (STJ), (d) apex to STJ, (e) apex to brachiocephalic artery (BCA), and (f) AV to BCA. RESULTS: In total, 44 LVAD patients (36 male, age 55.8 years, height 1.75 m) were included. The longitudinal cardiac dimensions were (a) 114.5 ± 12.1 mm, (b) 108.0 ± 12.4 mm, (c) 20.9 ± 2.9, (d) 135.4 ± 13.4 mm, (e) 206.0 ± 18.3, and (f) 91.5 ± 9.8 mm. Postoperatively, (a) and (b) decreased by 31.5% and 39.5%, respectively (N = 14). CONCLUSIONS: Longitudinal cardiac dimensions may be reduced by up to 40% after LVAD implantation. A better knowledge of these dimensions and their postoperative alterations in LVAD patients may improve surgical planning and help to design MCS devices with transventricular outflow cannula.

A systematic methodology for epicardial and epiaortic echocardiography in swine research models.

Background: Perioperative echocardiography is of paramount importance during cardiac surgery. Nonetheless, in the experimental large-animal setting, it might be challenging obtaining optimal imaging when using conventional imaging acquisition techniques, such as transthoracic and transesophageal screenings. Open-chest surgery allows epicardial echocardiographic assessment with direct contact between probe and heart, thus providing superior quality. Standard protocols regarding the use of epicardial ultrasound in swine for research purposes are lacking. Methods: Epicardial echocardiography was performed in 10 female German Landrace pigs undergoing cardiac surgery. A structured and comprehensive protocol for epicardial echocardiography was elaborated including apical, ventricular long and short axis, as well as epiaortic planes. All experiments were approved by the local board for animal welfare and conducted in accordance with the German animal protection law (TierSchG) and the ARRIVE guidelines. Conclusions: Systematic protocols using epicardial echocardiography may serve as an additional tool to assess cardiac dimensions and function in experimental scenarios with swine models.

Cardiac dimensions and hemodynamics in healthy juvenile Landrace swine.

BACKGROUND: Swine are frequently used as animal model for cardiovascular research, especially in terms of representativity of human anatomy and physiology. Reference values for the most common species used in research are important for planning and execution of animal testing. Transesophageal echocardiography is the gold standard for intraoperative imaging, but can be technically challenging in swine. Its predecessor, epicardial echocardiography (EE), is a simple and fast intraoperative imaging technique, which allows comprehensive and goal-directed assessment. However, there are few echocardiographic studies describing echocardiographic parameters in juvenile swine, none of them using EE. Therefore, in this study, we provide a comprehensive dataset on multiple geometric and functional echocardiographic parameters, as well as basic hemodynamic parameters in swine using EE. METHODS: The data collection was performed during animal testing in ten female swine (German Landrace, 104.4 ± 13.0 kg) before left ventricular assist device implantation. Hemodynamic data was recorded continuously, before and during EE. The herein described echocardiographic measurements were acquired according to a standardized protocol, encompassing apical, left ventricular short axis and long axis as well as epiaortic windows. In total, 50 echocardiographic parameters and 10 hemodynamic parameters were assessed. RESULTS: Epicardial echocardiography was successfully performed in all animals, with a median screening time of 14 min (interquartile range 11-18 min). Referring to left ventricular function, ejection fraction was 51.6 ± 5.9% and 51.2 ± 6.2% using the Teichholz and Simpson methods, respectively. Calculated ventricular mass was 301.1 ± 64.0 g, as the left ventricular end-systolic and end-diastolic diameters were 35.3 ± 2.5 mm and 48.2 ± 3.5 mm, respectively. The mean heart rate was 103 ± 28 bpm, mean arterial pressure was 101 ± 20 mmHg and mean flow at the common carotid artery was 627 ± 203 mL/min. CONCLUSION: Epicardial echocardiography allows comprehensive assessment of most common echocardiographic parameters. Compared to humans, there are important differences in swine with respect to ventricular mass, size and wall thickness, especially in the right heart. Most hemodynamic parameters were comparable between swine and humans. This data supports study planning, animal and device selection, reinforcing the three R principles in animal research.

Cardioaortic dimensions in German landrace pigs derived from cardiac magnetic resonance imaging.

Pigs are frequently applied as animal models in cardiovascular research due to their anatomical and physiological similarity to humans. For study planning and refinement, precise knowledge of the cardioaortic dimensions is essential. In a retrospective single-center study, the cardioaortic dimensions and left ventricular function of German Landrace pigs were assessed using cardiac MRI. All parameters were compared between male and female pigs and analyzed for correlation with body weight. In total, 15 pigs were included (7 male and 8 female, weight 60.9 ± 7.0 kg). The left ventricle revealed an end-diastolic diameter of 50.5 ± 4.4 mm and an ejection fraction of 51.2 ± 9.8%. The diameters of the ascending and descending aorta were 21.3 ± 2.3 and 16.2 ± 1.4 mm, respectively. There were no significant differences between male and female pigs, except that males had a smaller end-diastolic left ventricular volume (p = 0.041). A moderate correlation was found between body weight and the aortic annulus diameter (R = 0.57, p = 0.027). In conclusion, cardiac MRI allows precise quantification of porcine cardioaortic dimensions. For medical device testing, size differences between pigs and humans should be considered.

Intra-aortic band impairs transapical device implantation in a pig: a case report.

BACKGROUND: Anatomic anomalies in the ascending aorta may impair the implantation and testing of cardiovascular devices in humans and animal models. CASE PRESENTATION: We present the rare case of an intra-aortic band in a German Landrace pig. During terminal animal testing, the band hindered the implantation of a left ventricular assist device (LVAD) with transventricular outflow graft across the aortic valve. After lower partial sternotomy, epicardial echocardiography displayed an intraluminal echogenic structure at the sinotubular junction causing unspecific flow turbulences. Under cardiopulmonary bypass, coring of the left ventricular apex was performed. Due to strong resistance in the proximal aorta, accurate positioning of the transventricular LVAD outflow graft was impossible. After euthanasia, necropsy revealed a fibrous band located at the sinotubular junction, dividing the lumen of the ascending aorta. CONCLUSIONS: The occurrence of an intra-aortic band represents an extremely rare case of a most likely congenital anomaly. Awareness of such anomalies is important for planning and performing animal testing. Perioperative echocardiography may help to either remove such anomalies or allow discontinuing the procedure prior to device implantation.

Impact of an Accessory for Left Ventricular Assist Devices on Device Flow and Pressure Head In Vitro.

A novel accessory directing the blood from the outflow of a left ventricular assist device (LVAD) back through the left ventricular apex and across the aortic valve allows LVAD implantation via the left ventricular apex solely but may affect the LVAD performance. We quantified the effect of the accessory on LVAD flow and pressure head in vitro. In a mock circulatory loop, a centrifugal-flow LVAD (HeartMate 3, Abbott, Abbott Park, IL, USA) with (Accessory) and without the accessory (Control) was compared under physiological conditions using a water/glycerol solution as a blood substitute. The pump was operated at 4000, 5200, and 6400 rpm and 5 different resistance levels. Flow, inlet, and outlet pressure were measured, and pressure head was calculated. Compared to the Control, flow and pressure head in the Accessory group were reduced by an overall average of 0.26 L/min and 9.9 mmHg (all speeds and resistance levels). The highest decline in flow and pressure head occurred at the lowest resistance levels. In conclusion, the accessory leads to a reduction of LVAD flow and pressure head that is enhanced by decreases in resistance. Future developments in the LVAD accessory's design may reduce these effects and allow unimpaired LVAD performance and minimally invasive device implantation.

How do researchers perceive problems in research collaboration? Results from a large-scale study of German scientists.

In recent years, collaboration has become the norm in scientific knowledge production. Like other forms of collaboration, research collaborations (RCs) face specific problems that can jeopardize success. Against this background, the present study sought to gain a deeper understanding of the relevance of different collaboration problems and the interconnections among these problems. Building on previous insights into the most current problems, we addressed four major issues: (1) researchers' perceived relative relevance of collaboration problems in their projects (in terms of their occurrence), (2) differences in these perceptions based on the type of RC (e.g., number of subprojects and collaboration mode) and (3) on the characteristics of researchers, and (4) the co-occurrence of collaboration problems. Based on a representative survey of leading participants of RCs funded by the German Research Foundation (n = 5,326), we found that researchers experienced collaboration problems (e.g., fairness and communication problem) only to a small degree, and there were almost no differences regarding their perceived relevance. Furthermore, there were almost no significant differences concerning the perceived relevance of these problems depending on the type of RC or the individual researchers. However, the findings did reveal specific patterns of co-occurrence (e.g., relationship and difference problem). The results suggest that previous research may have overstated the relevance of collaboration problems in RCs. Instead, it seems that at least in Germany, collaborative research works better than one might assume.

Small-diameter bacterial cellulose-based vascular grafts for coronary artery bypass grafting in a pig model.

Surgical revascularization is the gold standard in most cases of complex coronary artery disease. For coronary artery bypass grafting, autologous grafts are state-of-the-art due to their long-term patency. A non-negligible amount of patients lack suitable bypass material as a result of concomitant diseases or previous interventions. As a promising alternative, tissue-engineered vascular grafts made of biomaterials such as bacterial cellulose (BC) are gaining more and more attention. However, the production of small-diameter grafts (inner diameter < 6 mm) of application-oriented length (> 5 cm) and their in vivo long-term patency remain challenging. In this study, grafts of 20 cm in length with an inner diameter of 3 mm were generated in a custom-made bioreactor. To potentially improve graft compliance and, therefore in vivo patency, BC was combined with an embedded cobalt-chromium mesh. The grafts were designed for in vivo endothelialization and specific surgical properties and implanted as an aortocoronary bypass in a left anterior descending occluded pig model (n = 8). Coronary angiography showed complete patency postoperatively at 4 weeks. Following 4 weeks in vivo, the grafts were explanted revealing a three-layered wall structure. Grafts were colonized by smooth muscle cells and a luminal layer of endothelial cells with early formation of vasa privata indicating functional remodeling. These encouraging findings in a large animal model reveal the great potential of small-diameter BC grafts for coronary and peripheral bypass grafting.

Understanding and Addressing Problems in Research Collaboration: A Qualitative Interview Study From a Self-Governance Perspective.

For collaborative research to be successful, understanding and solving collaboration problems is of paramount importance. However, theory-driven research on this issue at a general level is scarce. Drawing from two micro-oriented approaches (i.e., club theory and commons theory) and relying on self-governance as the basic principle for addressing collaboration problems, we aim to develop theoretically informed, concise and generalizable catalogs of problems and solutions based on the experiences and expectations of research collaboration participants. A series of expert interviews (N = 18) were conducted with leading researchers in Germany. Seven typical problems (e.g., lack of commitment or fairness) and 12 possible solutions (e.g., continuous evaluation or creating cognitive common ground) that can be applied within the self-regulatory framework were identified. The results provide a useful framework to further investigate problems and solutions as well as interlinkages between the two, and to improve research collaboration.

Postoperative administration of tranexamic acid as approach to reduce blood loss after open-heart surgery.

BACKGROUND: Tranexamic acid (TXA) reduces perioperative bleeding among patients undergoing heart surgery. It is uncertain whether its postoperative administration, after prior administration before cardiopulmonary bypass (CPB), has an additional benefit. OBJECTIVE: Our study aimed to evaluate whether the postoperative administration of TXA reduces the blood loss after heart surgery. METHODS: In a retrospective cohort study at the University Heart Center Dresden, patients who underwent on-pump open-heart surgery and received 1 g TXA before CPB were included. Patients with postoperative administration of 1 g TXA were compared to patients without. Primary endpoint was the postoperative blood loss within 24 hours. RESULTS: Among 2,179 patients undergoing heart surgery between 1 July 2013 and 31 October 2014, 92 (4.2%) received TXA postoperatively. After matching, 71 patients with postoperative administration of TXA were compared to 71 without (n = 142). Postoperative administration of TXA did not result in decreased blood loss (MD 146.7 mL; p = 0.064). There was no evidence of an increased risk for thromboembolic complications. CONCLUSIONS: The postoperative administration of TXA did not reduce blood loss. The use of TXA was shown to be safe in terms of thromboembolic events and hospital mortality. Unless there is no clear evidence, the postoperative administration of TXA should be restricted to patients with massive blood loss and signs of hyperfibrinolysis only.

Measuring cognitive performance in way that incorporates the concept of active and healthy ageing (AHA).

OBJECTIVES: To demonstrate that the mental-cognitive domain of the validated generic bio-functional status (BFS)/bio-functional age (BFA) assessment tool reflects cognitive performance, and so meets the needs of the European Innovation Partnership on Active and Healthy Ageing (EIP-AHA). STUDY DESIGN: Monocenter, cross-sectional, observational, non-interventional trial (Bern Cohort Study 2014, BeCS-14) (Cantonal Ethics Committee, KEK-BE 023112). MAIN OUTCOME MEASURES: Ratings on the mental-cognitive BFS domain and on a validated cognitive performance test battery (Inventar der Gedächtnisdiagnostik; IGD) in 47 healthy, educated, middle-class, midlife men and women. RESULTS: Mean cognitive performance was average in younger, and higher in better-educated individuals. Participants' BFA was 8.9 ± 6.6 year-equivalents below their chronological age. Subjects who performed better in the IGD (sub)domains also performed better in the BFS cognitive-mental function subdomain. Correlation analysis of the ratings in the BFS cognitive-mental function subdomain and total score on the IGD revealed that the highest correlations were achieved by the BFS parameters cognitive switching capability (r=-0.56, p < 0.001), strategic thinking (r=-0.49, p < 0.001), changeover capability (r=-0.50, p < 0.001) and stepping-stone-maze test (r=-0.51, p < 0.001). CONCLUSIONS: Ratings on the BFS cognitive-mental function subdomain correlated well with scores on a validated questionnaire for cognition assessment, the IGD. Therefore, the BFS/BFA assessment tool meets the needs of the EIP-AHA.

Measuring chronic stress exposure incorporating the active and healthy ageing (AHA) concept within the cross-sectional Bern cohort study 2014 (BeCS-14).

The aim of the study was to represent chronic stress exposure by a complex generic Active and Healthy (AHA) diagnostic assessment tool incorporating ICF. This is a single-centre, cross-sectional, observational, non-interventional, non-randomized trial in University based women's hospital, division of Gynecological Endocrinology and Reproductive Medicine. All participants followed a standardized, holistic battery of biopsychosocial assessments consisting of bio-functional status (BFS), bio-functional age (BFA) and the questionnaire for chronic stress exposure (TICS). 624 non-pediatric, non-geriatric subjects were recruited in the BeCS-14 cohort. The mean difference between chronological age and BFA was 7.8 ± 8.0 year equivalents. The mean stress level score assessed by SSCS was 13.2 with 45.4% being exposed to above average stress intensity. 22 BFS items (14 objective, 7 subjective) significantly correlated with chronic stress exposure (TICS-SSCS). The constructed sum score composed of SOC_L9 and complaint questionnaire (physical and emotional wellbeing) represented chronic stress exposure best (pearson-correlation value 0.564, p < 0.0001). Higher chronic stress exposure was associated with bio-functional pro-aging (less vitality) in both sexes. In conclusion, chronic stress is accepted as a major risk factor for developing non-communicable diseases (NCD). Our ICF compatible, complex, generic BFS/BFA assessment tool reflects chronic stress exposure and may be applied in various health care settings, e.g., in health promotion and prevention of NCDs.

Linking the menopause rating scale to the International classification of functioning, disability and health - A first step towards the implementation of the EMAS menopause health care model.

OBJECTIVES: To link the Menopause Rating Scale (MRS-II) to the International Classification of Functioning, Disability and Health (ICF) and present a clinical application of an ICF-based tool. STUDY DESIGN: The MRS-II was linked to the corresponding ICF category. The linked items were used to generate an ICF Categorical Profile. To broadly examine its feasibility in clinical practice, qualitative interviews with three patients were performed. MAIN OUTCOME MEASURES: Corresponding items of the MRS-II in the ICF. Perception of the ICF Categorical Profile from patients' perspective. RESULTS: A total of 44 concepts from the MRS-II were identified that could be linked to 24 different ICF categories, which all belonged to the component Body Functions. From patients' perspective, filling in the ICF Categorical Profile helped to structure their goals but did not improve the overview of symptoms. CONCLUSIONS: The ICF Categorical Profile could be a valuable tool in menopause healthcare; however, it is necessary to adapt the ICF for this specific use. An ICF Core Set needs to be developed in order to accomplish the goal of the European Menopause and Andropause Society and implement its Healthy Menopause Health Care Model in daily practice.

Illness perception in overweight and obesity and impact on bio-functional age.

PURPOSE: Obesity is pandemic. Yet, the success of most weight loss programmes is poor. The aim of the study was to assess illness perception in overweight/obese people and its impact on bio-functional age (BFA) reflecting physical, mental, emotional and social functioning. METHODS: 75 overweight/obese subjects from the cross-sectional Bern Cohort Study 2014 were included. Participants followed a validated "bio-functional status" test battery amended by the validated questionnaires Patiententheoriefragebogen (illness perception) and AD-EVA (eating and movement behaviour). BFA was calculated in subjects aged ≥ 35 years (n = 56). RESULTS: (1) Mental occupation with the cause of overweight/obesity was generally moderate to high, but decreasing with age. (2) The predominant theories for being overweight/obese were health behaviour (58.7%) and psychosocial factors (33.3%). (3) Overweight/obese people with psychosocial theories on illness causes were more likely to have emotional or disinhibited eating patterns. (4) Cognitive control of eating patterns increased with age in both sexes. (5) Overweight/obese people were still bio-functionally younger than their chronological age (8.6 ± 0.8 year equivalents), although (6) quality of life was below average and (7) the risk for functional pro-aging was increased in those being especially mentally occupied with causes for overweight/obesity (r = 0.38, p < 0.001) and those having psychosocial (r = 0.32, p < 0.05) or naturalistic theories (r = 0.47, p > 0.001). CONCLUSIONS: Consciously perceived psychosocial stress was found to be a main factor to disturb health and promote unhealthy cognitive patterns regulating eating and moving habits. Thus, successful weight reduction programmes should integrate subjective illness perceptions to not only improve the therapeutic outcome, but also functioning (BFA).

Towards ICF implementation in menopause healthcare: a systematic review of ICF application in Switzerland.

AIMS OF THE STUDY: To present a systematic literature review on the application and degree of implementation of the International Classification of Functioning, Disability and Health (ICF) across different health conditions and regions in Switzerland in order to develop an ICF classification of the climacteric syndrome in the medium term. METHODS: A systematic literature search was conducted through Embase and Medline covering the period between 2011 and August 2016. Inclusion criteria were the term ICF in title or abstract and Switzerland as the workplace of the first author. Identified publications were analysed as descriptive statistics. RESULTS: A total of 83 articles were included in the analysis. Forty-seven different first authors from 24 different institutions were identified. The majority of publications were from Swiss Paraplegic Research (68.7%) and focused on neurology (31.3%). Forty-six cohort studies were identified. In most of them, the ICF was used to set up a general language for comparing patients' information (82.9%). Only one paper from the medical specialty gynaecology was identified; this was on breast cancer. No paper on the menopause was found. CONCLUSION: In Switzerland, the ICF is actively used in various areas of healthcare, especially in the field of neurology and rehabilitation. There is a need for ICF core sets in other medical fields, such as menopause healthcare, in order to accomplish the goal of the European Menopause and Andropause Society, which is a healthcare model for healthy menopause and aging.