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1.
Scand Cardiovasc J ; 57(1): 2184861, 2023 12.
Article in English | MEDLINE | ID: mdl-36883910

ABSTRACT

Objectives. Readmission rates following open cardiac surgery are high, affecting patients and the cost of care. This study aimed to investigate the effect of early additional follow-up after open cardiac surgery when 5th-year medical students conducted follow-ups under the supervision of physicians. The primary endpoint was unplanned cardiac-related readmissions within one year. The secondary outcomes were the detection of impending complications and health-related quality of life (HRQOL). Methods. Patients undergoing open cardiac surgery were prospectively included. For intervention, additional follow-up visits, including point-of-care ultrasound, were conducted by supervised 5th-year medical students on postoperative days 3, 14 and 25. Unplanned cardiac-related readmissions, including emergency department visits, were registered within the first year of surgery. Danish National Health Survey 2010 questionnaire was used for HRQOL. In standard follow-up, all patients were seen 4-6 weeks postoperative. Results. For data analysis, 100 of 124 patients in the intervention group and 319 of 335 patients in the control group were included. The 1-year unplanned readmission rates did not differ; 32% and 30% in the intervention and control groups, respectively (p = 0.71). After discharge, 1% of patients underwent pericardiocentesis. The additional follow-up initiated scheduled drainage, contrary to more unscheduled/acute drainages in the control group. Pleurocentesis was more common in the intervention group (17% (n = 17) vs 8% (n = 25), p = 0.01) and performed earlier. There was no difference between groups on HRQOL. Conclusion. Supervised student-led follow-up of newly cardiac-operated patients did not alter readmission rates or HRQOL but may detect complications earlier and initiate non-emergent treatment of complications.


Subject(s)
Cardiac Surgical Procedures , Quality of Life , Humans , Risk Factors , Follow-Up Studies , Postoperative Complications/etiology , Postoperative Complications/therapy , Postoperative Complications/diagnosis , Cardiac Surgical Procedures/adverse effects , Students , Patient Readmission
2.
Patient Educ Couns ; 104(11): 2756-2762, 2021 11.
Article in English | MEDLINE | ID: mdl-33836939

ABSTRACT

OBJECTIVE: To understand how patients experience participation in student encounters. METHODS: Qualitative semi-structured telephone interviews with ten cardiac surgery patients who had attended voluntary postoperative consultations in a student outpatient clinic. The interview guide included questions about reasons for and experiences of being part of a teaching situation. Interviews were analysed through inductive thematic analysis where pieces of text in each interview were assigned different codes and condensed into themes. RESULTS: The patients expressed a duality in their reasons for participating in student consultations: (1) a personal need for assurance (safety) and (2) a wish to help students (altruism). Students were perceived as professional and sometimes insecure. Being part of an educational situation was meaningful to the patients because they did not feel objectified. Knowing that there was a backup supervisor made the patients feel safe even though the supervisor was not present during all parts of the consultation. CONCLUSIONS: Patients experienced safety, understood their role in all parts of the consultation, and shared a wish to help students learn. PRACTICE IMPLICATIONS: A sequential consultation model alternating between student- and supervisor-driven supervision can balance student autonomy and patient safety. This knowledge could guide future patient-centred medical education in student clinics.


Subject(s)
Education, Medical, Undergraduate , Students, Medical , Ambulatory Care Facilities , Humans , Learning , Patient Outcome Assessment , Qualitative Research , Students
3.
Dan Med J ; 68(4)2021 Mar 24.
Article in English | MEDLINE | ID: mdl-33829990

ABSTRACT

INTRODUCTION: Radiofrequency catheter ablation (RFA) is the treatment of choice for a variety of cardiac arrhythmias in adults. RFA is considered effective and is associated with few complications. We aimed to review the characteristics and outcomes of invasive electrophysiological study (EPS) and RFA in children with supraventricular tachyarrhythmia. METHODS: Consecutive patients younger than 16 years of age undergoing EPS and possible RFA from January 2009 to September 2018 at Aarhus University Hospital (uptake three million people) were reviewed retrospectively. Procedural and outcome data were collected from patient charts and from the Danish Ablation Database. Numbers (%) or median (range) are reported. RESULTS: A total of 304 patients (148 girls) underwent EPS (352 procedures). RFA was performed in 246 patients (279 procedures), aged 13 (1-15) years and weighing 46 (6-99) kg. Treatment success was achieved in 195 (79%) of the initial procedures. Using more than one procedure, 227 (92%) patients were free from arrhythmia after 89 (26-143) months of follow-up. The procedure time was 60 (22-222) min. and ablation time 2 (1-23) min. Major complications occurred in two cases. One patient developed transient superior vena cava syndrome and one patient developed an atrioventricular block requiring pacemaker implantation. CONCLUSIONS: RFA may be performed in children with a high success rate and a low but not negligible risk of complications. FUNDING: none. TRIAL REGISTRATION: Approval was obtained from the Danish Data Protection Agency (1-16-02-430-13).


Subject(s)
Catheter Ablation , Superior Vena Cava Syndrome , Tachycardia, Supraventricular , Adolescent , Arrhythmias, Cardiac , Child , Child, Preschool , Female , Humans , Infant , Male , Retrospective Studies , Tachycardia, Supraventricular/surgery , Treatment Outcome
4.
Interact Cardiovasc Thorac Surg ; 28(1): 65-70, 2019 01 01.
Article in English | MEDLINE | ID: mdl-29992278

ABSTRACT

OBJECTIVES: To develop and evaluate a novel mitral annuloplasty ring with selective flexibility for septal-lateral contraction and rigidity for septal-lateral dilatation in an acute porcine model. METHODS: The novel mitral annuloplasty ring was designed with slits in the luminal posterior segment and annular lateral segments. The slits were designed to allow inward motion during contraction and to block outward motion during dilation. The novel mitral annuloplasty ring was tested in vitro with a dedicated mechanical test bench, followed by in vivo characterization, using sonomicrometry and echocardiography for annular and leaflet geometry, in an acute porcine model. RESULTS: From the in vitro characterization, we verified that the ring could easily contract (0.7 mm/N) in the septal-lateral dimension, while dilatation was restrained (0.4 mm/N). In vivo characterization showed a cyclic range of 2.8 ± 0.0 mm for septal-lateral contraction. CONCLUSIONS: A novel saddle-shaped remodelling mitral annuloplasty ring was developed with selective flexibility for septal-lateral contraction and rigidity for septal-lateral dilatation. The advantages of this specific ring is that it re-establishes the coaptation plane, ensures leaflet mobility and septal-lateral flexibility and at the same time improves tissue adaptation and thereby decreases the risk of ring dehiscence and redilatation of the mitral annulus. This concept may prove beneficial for patients with ischaemic mitral valve regurgitation or degenerative valve disease.


Subject(s)
Heart Valve Prosthesis Implantation/methods , Heart Ventricles/physiopathology , Mitral Valve Annuloplasty/methods , Mitral Valve Insufficiency/surgery , Mitral Valve/surgery , Ventricular Remodeling , Animals , Disease Models, Animal , Echocardiography , Heart Ventricles/diagnostic imaging , Mitral Valve/diagnostic imaging , Mitral Valve Insufficiency/diagnosis , Swine
5.
J Heart Valve Dis ; 27(1): 32-37, 2018 Jan.
Article in English | MEDLINE | ID: mdl-30560597

ABSTRACT

BACKGROUND: Currently, several different flexible mitral annuloplasty rings are available, and their efficacy for surgical repair of the mitral valve is, in general, considered equal. However, clinical experience indicates differences in remodeling capacity that have not yet been quantitatively assessed. The study aim was to compare the biomechanical properties of two commonly used flexible mitral annuloplasty rings in an acute pig model. METHODS: Medtronic Simulus Flex (n = 5) and Medtronic Duran AnCore (n = 7) flexible mitral annuloplasty rings were implanted in pigs (bodyweight 80 kg). The native mitral valve was used as a reference (n = 7). Mitral annular dynamics and dimensions were assessed using 11 sonomicrometry crystals placed in the mitral apparatus. A dedicated force transducer was used to detect deformational force transmission between the annuloplasty ring and the mitral annulus. RESULTS: Cyclic changes in mitral annular circumference and commissure-commissure distance were significantly reduced in the Simulus Flex group compared to the Duran AnCore group (p = 0.025 and p <0.01, respectively). In the Simulus Flex group, smaller deformational forces were recorded compared to the Duran AnCore group, but the difference was not statistically significant (p = 0.52 and p = 0.06 for the septal-lateral and the commissure-commissure force measurements, respectively). CONCLUSIONS: The Simulus Flex ring showed significantly more remodeling capacity than the Duran AnCore ring, but the latter ring preserved the natural dynamics of the mitral valve to a greater degree. Insights into these biomechanical differences may facilitate strategies for surgical reconstruction in degenerative mitral valve disease, especially in patients with excessive amounts of tissue and who are at risk of systolic anterior motion of the mitral valve.


Subject(s)
Heart Valve Prosthesis , Mitral Valve Annuloplasty/instrumentation , Mitral Valve/surgery , Animals , Biomechanical Phenomena , Disease Models, Animal , Mitral Valve/physiology , Prosthesis Design , Swine
6.
J Biomech ; 71: 52-58, 2018 04 11.
Article in English | MEDLINE | ID: mdl-29428174

ABSTRACT

OBJECTIVE: Tricuspid valve reconstruction using a small intestinal submucosal porcine extracellular matrix (ECM) tube graft is hypothesized to be durable for six months and show signs of recellularization and growth potential. The purpose was to histologically and biomechanically test ECM valves before and after six months of implantation in pigs for comparison with native valves. METHODS: Ten 60 kg pigs were included, which survived tricuspid valve tube graft insertion. Anterior and septal tricuspid leaflets were explanted from all animals surviving more than one month and examined histologically (n = 9). Endothelialization, collagen content, mineralization, neovascularization, burst strength and tensile strength were determined for native valves (n = 5), ECM before implantation (n = 5), and ECM after six months (n = 5). RESULTS: Collagen density was significantly larger in ECM at implantation (baseline) compared to native leaflet tissue (0.3 ±â€¯0.02 mg/mm3 vs. 0.1 ±â€¯0.03 mg/mm3, p < .0001), but collagen density decreased and reached native leaflet collagen content, six months after ECM implantation (native vs. ECM valve at six months: 0.1 ±â€¯0.03 mg/mm3 vs. 0.2 ±â€¯0.05 mg/mm3, p = .8). Histologically, ECM valves showed endothelialization, host cell infiltration and structural collagen organization together with elastin generation after six months, indicating tissue remodeling and -engineering together with gradual development of a close-to-native leaflet structure without foreign body response. CONCLUSIONS: ECM tricuspid tube grafts were stronger than native leaflet tissue. Histologically, the acellular ECM tube grafts showed evidence of constructive tissue remodeling with endothelialization and connective tissue organization. These findings support the concept of tissue engineering and recellularization, which are prerequisites for growth.


Subject(s)
Extracellular Matrix , Heart Valve Prosthesis , Tricuspid Valve , Animals , Calcinosis/pathology , Collagen , Elastin , Swine , Tensile Strength , Tissue Engineering
7.
J Cardiovasc Magn Reson ; 19(1): 93, 2017 Nov 27.
Article in English | MEDLINE | ID: mdl-29178894

ABSTRACT

BACKGROUND: Chronic pulmonary regurgitation often leads to myocardial dysfunction and heart failure. It is not fully known why secondary hypertrophy cannot fully protect against the increase in wall stress brought about by the increased end-diastolic volume in ventricular dilation. It has been assumed that mural architecture is not deranged in this situation, but we hypothesised that there might be a change in the pattern of orientation of the aggregations of cardiomyocytes, which would contribute to contractile impairment. METHODS: We created pulmonary valvular regurgitation by open chest, surgical suturing of its leaflets in seven piglets, performing sham operations in seven control animals. Using cardiovascular magnetic resonance imaging after 12 weeks of recovery, we demonstrated significantly increased right ventricular volumes in the test group. After sacrifice, diffusion tensor imaging of their hearts permitted measurement of the orientation of the cardiomyocytes. RESULTS: The helical angles in the right ventricle approached a more circumferential orientation in the setting of right ventricular RV dilation (p = 0.007), with an increased proportion of surface-parallel cardiomyocytes. In contrast, this proportion decreased in the left ventricle. Also in the left ventricle a higher proportion of E3 angles with a value around zero was found, and conversely a lower proportion of angles was found with a numerical higher value. In the dilated right ventricle the proportion of E3 angles around -90° is increased, while the proportion around 90° is decreased. CONCLUSION: Contrary to traditional views, there is a change in the orientation of both the left ventricular and right ventricular cardiomyocytes subsequent to right ventricular dilation. This will change their direction of contraction and hinder the achievement of normalisation of cardiomyocytic strain, affecting overall contractility. We suggest that the aetiology of the cardiac failure induced by right vetricular dilation may be partly explained by morphological changes in the myocardium itself.


Subject(s)
Hypertrophy, Right Ventricular/physiopathology , Myocytes, Cardiac/pathology , Ventricular Function, Left , Ventricular Function, Right , Ventricular Remodeling , Animals , Diffusion Tensor Imaging , Disease Models, Animal , Female , Hypertrophy, Right Ventricular/diagnostic imaging , Hypertrophy, Right Ventricular/etiology , Hypertrophy, Right Ventricular/pathology , Magnetic Resonance Imaging , Myocardial Contraction , Pulmonary Valve Insufficiency/complications , Pulmonary Valve Insufficiency/physiopathology , Sus scrofa , Time Factors
8.
J Heart Valve Dis ; 26(3): 295-303, 2017 05.
Article in English | MEDLINE | ID: mdl-29092114

ABSTRACT

BACKGROUND AND AIM OF THE STUDY: The configuration of the native annulus changes from nearly flat in the diastolic phase to saddle-shaped in the systolic phase. The present study was conducted to test a novel remodeling annuloplasty ring with built-in septal-lateral fixation and commissural axial flexibility so as to maintain the change in annular saddle shape. The study aim was to evaluate the in-vivo biomechanical performance of the novel annuloplasty ring, compared with the native valve and a semi-rigid and rigid annuloplasty ring. METHODS: All measurements were performed in vivo using a porcine model. A total of 28 pigs (bodyweight ca. 80 kg) were randomized to four groups: (i) with no ring; (ii) with a novel remodeling ring; (iii) with a semi-rigid ring (Physio I Ring, Edwards Lifesciences); and (iv) with a rigid ring (Classic Annuloplasty Ring, Edwards Lifesciences). Force measurements were performed using a dedicated transducer to determine remodeling capacity of the annuloplasty rings. Geometric parameters were measured by implanting sonomicrometry crystals along the mitral annulus. RESULTS: All ring groups significantly restricted the cyclic change of the mitral annulus compared with the 'no-ring' group. The change and maximum value of the annular height were maintained for the novel ring but were significantly decreased for the rigid and semi-rigid rings compared with the 'no-ring' group. Mitral annular force measurements confirmed that the overall remodeling capacity of the novel ring was comparable with the conventional ring groups, and significantly higher in the septal-lateral direction compared to the semi-rigid ring. CONCLUSIONS: In-vivo geometry and force measurements indicated that the intended design features of the new device were successfully provided. The novel ring concept with remodeling properties, combined with the advantages of a flexible annuloplasty ring, is unique. The maintenance of annular saddle shape and cyclic change in annular height may be an important step towards improved mitral valve repair.


Subject(s)
Heart Valve Prosthesis Implantation/instrumentation , Heart Valve Prosthesis , Hemodynamics , Mitral Valve Annuloplasty/instrumentation , Mitral Valve/surgery , Animals , Biomechanical Phenomena , Echocardiography , Heart Valve Prosthesis Implantation/adverse effects , Materials Testing , Mitral Valve/diagnostic imaging , Mitral Valve/physiopathology , Mitral Valve Annuloplasty/adverse effects , Models, Animal , Prosthesis Design , Stress, Mechanical , Sus scrofa
9.
Interact Cardiovasc Thorac Surg ; 24(6): 918-924, 2017 06 01.
Article in English | MEDLINE | ID: mdl-28329138

ABSTRACT

OBJECTIVES: Tricuspid valve reconstruction using small intestinal submucosal extracellular matrix (ECM) designed as a tube graft is possible in severe valve pathology. Using cardiac magnetic resonance imaging (MRI) and digital photograph imaging, valves were evaluated after 6 months in a porcine model. METHODS: Ten 60 kg pigs received a tricuspid valve tube graft. A baseline MRI was performed after 2 weeks ( n = 8). A follow-up MRI was performed in three of five 6 months' survivors to assess function and haemodynamics of the tricuspid tube graft. Valves were explanted in five animals for gross examination. No statistical comparisons were made due to low numbers. RESULTS: : Compared to the original tube graft, leaflet area and leaflet height decreased after 6 months (32 ± 0 vs 14.7 ± 4 cm 2 and 3.2 ± 0 vs 1.7 ± 0.3 cm, respectively). Both imaging modalities showed septal dehiscence in all tube grafts after 6 months causing haemodynamically severe paravalvular regurgitation. Cardiac MRI showed a significant remodelling of the right ventricular and annular dimensions. The cardiac output decreased (67 ± 16 vs 34 ± 5 ml/min/kg), while right ventricular stroke volume increased from 64.4 ± 14.6 to 107 ± 63.9 ml. This corresponded to a paravalvular regurgitant volume increasing from 7.2 ± 7.3 to 71.7 ± 69.6 ml. CONCLUSIONS: The ECM tube grafts seemed to remodel over time with loss of redundant ECM material. However, tube graft dehiscence caused severe tricuspid paravalvular regurgitation and heart failure. These data suggest that surgical reinforcement, e.g. adjunct annuloplasty, should be considered to improve durability.


Subject(s)
Cardiac Valve Annuloplasty/methods , Heart Valve Prosthesis Implantation/methods , Heart Ventricles/physiopathology , Intestinal Mucosa/transplantation , Tricuspid Valve Insufficiency/surgery , Tricuspid Valve/surgery , Ventricular Remodeling , Animals , Disease Models, Animal , Heart Ventricles/diagnostic imaging , Hemodynamics , Intestine, Small/transplantation , Magnetic Resonance Imaging, Cine , Swine , Tricuspid Valve Insufficiency/physiopathology , Ventricular Function, Left/physiology
10.
Interact Cardiovasc Thorac Surg ; 24(5): 683-690, 2017 05 01.
Article in English | MEDLINE | ID: mdl-28329364

ABSTRACT

OBJECTIVES: To characterize the remodelling effects and deformational forces of normosized rigid, semirigid and flexible mitral annuloplasty rings after implantation in healthy pigs. METHODS: Measurements were performed in vivo with 80-kg porcine animals. Twenty-eight animals were randomized into a no ring group, a flexible ring group (Duran AnCore Ring, Medtronic, Minneapolis, MN, USA), a rigid ring group (Carpentier-Edwards Classic annuloplasty ring, Edwards Lifesciences, Irvine, CA, USA) and a semirigid ring group (Carpentier-Edwards Physio I annuloplasty ring, Edwards Lifesciences). Sonomicrometry crystals were implanted together with an annuloplasty ring and a dedicated mitral annular force transducer. The mitral annuloplasty rings were compared with respect to annular geometry and mitral annular forces. RESULTS: Cyclic changes in the mitral annulus (MA) circumference were significantly lower for all ring groups (flexible: 7 ± 3 mm, semirigid: 4 ± 2 mm and rigid: 2 ± 1 mm) compared to the no ring group (11 ± 5 mm), implying the remodelling capacity of all annuloplasty rings. The cyclic change of the MA area and the septa-lateral and inter-commissural distances were equal in the semirigid and rigid ring groups and significantly lower compared to the no ring and flexible ring groups, suggesting a stronger and equal remodelling effect in the semirigid and rigid ring groups. Forces measured in the transducer reflected the remodelling capacity of the annuloplasty rings and were in general lower for the semirigid and rigid ring groups compared to the no ring and flexible ring groups. Especially the forces in the inter-commissural direction were significantly reduced for the semirigid and rigid ring groups (semi-rigid: 1.4 ± 0.8 N, rigid: 1.2 ± 0.8 N) compared to the no ring and flexible ring groups (no ring: 3.0 ± 1.1 N, flexible: 3.4 ± 1.6 N). CONCLUSIONS: This study is the first to describe different remodelling effects and deformational forces of normosized mitral annuloplasty rings in vivo . Insights into the relationship between the remodelling effects and the accumulated forces of different mitral annuloplasty rings may have implications for ring selections in an aetiology-based mitral valve repair strategy. We propose the application of such a biomechanical approach for quantitative comparison of mitral annuloplasty rings and for future innovations on a rational basis.


Subject(s)
Heart Valve Prosthesis , Mitral Valve Annuloplasty/methods , Mitral Valve Insufficiency/surgery , Mitral Valve/surgery , Animals , Disease Models, Animal , Hemodynamics , Mitral Valve Insufficiency/physiopathology , Prosthesis Design , Swine
11.
Ann Thorac Surg ; 104(2): 599-605, 2017 Aug.
Article in English | MEDLINE | ID: mdl-28242076

ABSTRACT

BACKGROUND: Stentless porcine extracellular matrix tricuspid tube grafts were developed for tricuspid valve reconstruction. The purpose of this study was to conduct an echocardiographic assessment of the performance of native and tube graft leaflets in an acute porcine model. METHODS: Fourteen 65-kg pigs were randomly assigned to tube graft (n = 7) or control with native valve preservation (n = 7). Epicardial echocardiography was performed at baseline after sternotomy, after valve operation, and after hemodynamic stabilization. RESULTS: No baseline differences were found (p > 0.05). All valves were competent with only a mild central regurgitant jet in two tube grafts and two native valves. Tube graft valves were compared with native valves. Anterior-septal leaflet coaptation length (18 ± 6 mm versus 6 ± 1 mm, p < 0.0005), coaptation height (20 ± 9 mm versus 9 ± 4 mm, p < 0.005), and anterior leaflet length (31 ± 1 mm versus 22 ± 2 mm, p < 0.00005) were all significantly larger in the tube graft valves. The billowing index (0.8 ± 0.1 versus 0.9 ± 0.1, p > 0.05) and tenting height (5 ± 1 mm versus 4 ± 2 mm, p > 0.1) were not significantly different. Leaflet excursion angles for both leaflets were not significantly different between the native and tube graft valves (p > 0.1). CONCLUSIONS: In a porcine experimental model, a competent tricuspid valve was constructed using extracellular matrix tube graft material. Coaptation geometry was significantly different from native valves with an increased coaptation zone because of excessive leaflet tissue in the tube graft valves. The tube graft tended to prolapse into the atrium, but it did not compromise the motion and competence of the leaflets.


Subject(s)
Cardiac Surgical Procedures/methods , Heart Valve Diseases/surgery , Heart Valve Prosthesis , Plastic Surgery Procedures/methods , Tissue Engineering , Tricuspid Valve/surgery , Animals , Disease Models, Animal , Echocardiography, Transesophageal , Heart Valve Diseases/diagnosis , Prosthesis Design , Swine , Tricuspid Valve/diagnostic imaging
12.
Eur J Cardiothorac Surg ; 51(5): 836-843, 2017 May 01.
Article in English | MEDLINE | ID: mdl-28175268

ABSTRACT

OBJECTIVES: Investigate myocardial stress adaptation and remodelling capacity of a rigid and semi-rigid mitral annuloplasty ring. METHODS: The annuloplasty rings were characterized in vitro in a mechanical setup with tensile and compressive forces from 0 to 3 N. The rings were tested with and without fixation of the ring to imitate the effect of annular implantation. In vivo measurements were performed with 21 porcine animals randomized into: A no ring group, a rigid ring group (Classic Annuloplasty Ring TM , Edwards Lifesciences) and a semi-rigid ring group (Physio I Annuloplasty Ring, Edwards Lifesciences). The rings were implanted together with a force transducer and sonomicrometry was used for geometry measurements. RESULTS: The flexibility range of the semi-rigid ring was 7.6 and 2.4 mm in the septal-lateral and commissural direction, respectively. With fixation the flexibility was reduced to 1.0 and 0.6 mm, similar to the rigid ring without fixation. In vivo measurements indicated that the rigid and semi-rigid rings equally restrict the annular movement. Septal-lateral flexibility of the semi-rigid ring was not observed. Both rings induced force absorption in the ring and sutures due to the annular fixation. The absorbed forces were significantly lower for the semi-rigid ring in the posterior segment and septal-lateral direction. CONCLUSIONS: This study demonstrates the importance of correct fixation when characterizing annuloplasty rings. The annular movement of the semi-rigid ring was similar to the rigid ring when implanted at the mitral annulus as confirmed in vitro . Despite this the semi-rigid ring demonstrated a favourable stress adaptation which could potentially decrease the risk of ring dehiscence.


Subject(s)
Heart Valve Prosthesis , Mitral Valve Annuloplasty/instrumentation , Mitral Valve/physiology , Mitral Valve/surgery , Animals , Biomechanical Phenomena , Heart/physiology , Pliability , Prosthesis Design , Stress, Mechanical , Swine
13.
Ugeskr Laeger ; 178(50)2016 Dec 12.
Article in Danish | MEDLINE | ID: mdl-27966411

ABSTRACT

INTRODUCTION: Each December Santa's elves spread Christmas joy (JN). Laughter and humour may influence health and stress level. No other study has investigated the effect of JN on the good spirit (DGH) among healthcare professionals. MATERIAL AND METHODS: We performed a single-centre blinded intervention study with crossover at three hospital departments. JN intervention of three days was randomized. Median ± standard deviation was given. The level of significance was p < 0.05. RESULTS: During a four-week period, we made 24 observations (response rate 67). The laugh index increased from 0.02 in November to 0.03 in December (without JN) and further to 0.05 with JN. At one department, the rise was significant. At a department without morning coffee, the DGH level raised after JN intervention corresponding to the level at the departments with morning coffee before JN intervention. CONCLUSION: Christmas atmosphere tended to increase DGH at the morning conferences. JN tended to have an additive effect. JN exposure may be beneficial. FUNDING: The study did not receive any funding. TRIAL REGISTRATION: The trial was not registered and was kept secret for the participants in accordance with the tradition of Santa's elves.


Subject(s)
Holidays/psychology , Laughter , Physicians/psychology , Happiness , Hospital Departments , Humans
14.
J Biomech ; 49(5): 742-748, 2016 Mar 21.
Article in English | MEDLINE | ID: mdl-26903412

ABSTRACT

Limited knowledge exists about the forces acting on mitral valve annuloplasty repair devices. The aim of this study was to develop a new mitral annular force transducer to measure the forces acting on clinically used mitral valve annuloplasty devices. The design of an X-shaped transducer in the present study was optimized for simultaneous in- and out-of-plane force measurements. Each arm was mounted with strain gauges on four circumferential elements to measure out-of-plane forces, and the central parts of the X-arms were mounted with two strain gauges to measure in-plane forces. A dedicated calibration setup was developed to calibrate isolated forces with tension and compression for in- and out-of-plane measurements. With this setup, it was possible with linear equations to isolate and distinguish measured forces between the two planes and minimize transducer arm crosstalk. An in-vitro test was performed to verify the crosstalk elimination method and the assumptions behind it. The force transducer was implanted and evaluated in an 80kg porcine in-vivo model. Following crosstalk elimination, in-plane systolic force accumulation was found to be in average 4.0±0.1N and the out-of-plane annular segments experienced an average force of 1.4±0.4N. Directions of the systolic out-of-plane forces indicated movements towards a saddle shaped annulus, and the transducer was able to measure independent directional forces in individual annular segments. Further measurements with the new transducer coupled with clinical annuloplasty rings will provide a detailed insight into the biomechanical dynamics of these devices.


Subject(s)
Mitral Valve Annuloplasty , Transducers , Animals , Mitral Valve/surgery , Stress, Mechanical , Swine , Systole
15.
Ann Thorac Surg ; 101(1): 125-32, 2016 Jan.
Article in English | MEDLINE | ID: mdl-26365673

ABSTRACT

BACKGROUND: Stentless porcine extracellular matrix tricuspid tubular valves have been developed for tricuspid valve reconstruction. The purpose of this study was to compare biomechanical and functional performance of native and tube graft valves in an acute porcine model. METHODS: Twenty-two 65-kg pigs were randomized to tube graft or control with native valve preservation. Anterior papillary muscle force was measured with a dedicated force transducer. Microtip pressure catheters were placed in the right atrium and ventricle. Leaflet motion and three-dimensional valve geometry were evaluated using 13 sonomicrometry crystals: six in the tricuspid annulus, one on each leaflet free edge, one on each papillary muscle tip, and one in the right ventricular apex. RESULTS: No regurgitation and no significant differences in intracavitary pressures, annular motion, or leaflet excursion angles were observed after tube graft implantation (p > 0.05). Compared with the native valve, the tricuspid annulus, leaflet orifice area, annular diameters, and the septal segment of the annulus were significantly smaller in the tube graft group (p < 0.05). Maximum anterior papillary muscle force was significantly lower in the tube graft group (p < 0.005). The implantation technique led to an annular circumferential downsizing of 20% ± 17%. CONCLUSIONS: An extracellular matrix tube graft implanted in the tricuspid position produces a competent valve with physiologic performance that, despite downsizing, makes the tube graft an attractive alternative to valve replacement. The downsizing of the implantation should be considered when planning tube graft size and may be potentially beneficial by relieving tension on the repaired tissue, thereby increasing durability.


Subject(s)
Atrial Pressure/physiology , Extracellular Matrix , Tricuspid Valve Insufficiency/surgery , Tricuspid Valve/surgery , Ventricular Pressure/physiology , Animals , Biomechanical Phenomena , Disease Models, Animal , Imaging, Three-Dimensional , Prosthesis Design , Swine , Tricuspid Valve/pathology , Tricuspid Valve Insufficiency/physiopathology
16.
Cardiovasc Eng Technol ; 6(2): 185-92, 2015 Jun.
Article in English | MEDLINE | ID: mdl-26577234

ABSTRACT

Mitral valve repair with annuloplasty is often favoured over total valve replacement. In order to develop and optimize new annuloplasty ring designs, it is important to study the complex biomechanical behaviour of the valve annulus and the subvalvular apparatus with simultaneous in- and out-of-plane restraining force measurements. A new flat D-shaped mitral valve annular force transducer was developed. The transducer was mounted with strain gauges to measure strain and calibrated to provide simultaneous restraining forces in- and out of the mitral annular plane. The force transducer was implanted and evaluated in an 80 kg porcine experimental model. Accumulation of out-of-plane restraining forces, creating strain in the anterior segment were 0.7 ± 0.0 N (towards apex) and an average force accumulation of 1.5 ± 0.3 N, creating strain in the commissural segments (away from apex). The accumulations of in-plane restraining forces, creating strain on the inner side of the ring were 1.7 ± 0.2 N (away from ring center). A new mitral annular force transducer was successfully developed and evaluated in vivo. The transducer was able to measure forces simultaneously in different planes. Initial indications point towards overall agreement with previous individual force measurements in- and out-of the mitral annular plane. This can provide more detailed insight into the annular force distribution, and could potentially improve the level of evidence based mitral valve repair and support the development of future mitral annuloplasty devices.


Subject(s)
Heart Valve Prosthesis Implantation/methods , Mitral Valve Annuloplasty/instrumentation , Mitral Valve Annuloplasty/methods , Mitral Valve/physiology , Mitral Valve/surgery , Animals , Biomechanical Phenomena , Cardiovascular Diseases/complications , Cardiovascular Diseases/economics , Cardiovascular Diseases/mortality , Heart Valve Prosthesis Implantation/instrumentation , Mitral Valve/pathology , Models, Cardiovascular , Prosthesis Design , Plastic Surgery Procedures/instrumentation , Plastic Surgery Procedures/methods , Stress, Mechanical , Swine , Ventricular Function, Left/physiology
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