Ultrafast Plasmon Dynamics in Crystalline LiF Triggered by Intense Extreme UV Pulses.

An extreme ultraviolet pump and visible-light probe transmission experiment in crystalline LiF, carried out at the Free Electron Laser facility FERMI, revealed an oscillating time dependence of the plasmon mode excited in the high-density high-temperature electron plasma. The effect is interpreted as a fingerprint of the electron-ion interaction: the ion motion, shaped by the electron dynamic screening, induces, in turn, electron density fluctuations that cause the oscillation of the plasmon frequency at the timescale of the ion dynamics. Fitting the high resolution transmission data with an RPA model for the temperature-dependent dielectric function, which includes electron self-energy and electron-ion coupling, confirms the interpretation of the time modulation of the plasmon mode.

Case report - coronary vasospasm in transplanted heart: a puzzling phenomenon.

BACKGROUND: Coronary artery spasm (CAS) is an underdiagnosed disease especially in heart transplant patients, and in those patients the etiology and pathophysiology remain largely unknown, although it has been associated with cardiac allograft vasculopathy or graft rejection. CASE PRESENTATION: We report the case of a heart-transplant patient whose cardiac graft experienced two coronary vasospasms: the first before transplantation, and the other at one-month of a postoperative course complicated by primary graft failure. CONCLUSION: Our case illustrates that a transplanted heart predisposed with coronary vasospasm may suffer from early relapse in the recipient despite of complete post-surgical autonomic denervation. Exacerbated endothelial dysfunction of the donor heart after transplant, with the addition of systemic factors in the recipient may be involved in the genesis of this puzzling phenomenon.

[General recommendations for medical treatment after heart transplantation]. / Aspects médicaux autour de la transplantation cardiaque en 2014.

Heart transplantation remains the treatment of choice in selected patients with severe heart failure (HF) despite optimal medical therapy. Since long-term survival after HTX is improving, there is a growing need for evidence-based strategies that reduce long-term mortality resulting from both immunological and non-immunological risk. This manuscript summarizes recommendations for treatment of transplant vasculopathy, malignancy after transplantation, and prevention of corticosteroid induced bone disease. Based on actual understanding of cardiovascular risk factors in the population, preservation of renal function, prevention and treatment of hyperlipidemia and diabetes, as well as blood pressure control play an important role in the long-term follow-up after heart transplantation.

[Long-term mechanical circulatory support: where do we stand in 2013?]. / Assistance circulatoire chronique: le point en 2013.

With the advent of new technologies, experience with long-term mechanical circulatory support (MCS) is rapidly growing. Candidates to MCS are selected based on concepts, strategies and classifications that are specific to this indication. As results drastically improve, supported by stronger scientific evidence, the trend is towards earlier implantation. An adequate pre-implant follow-up is mandatory in order to avoid missing the best window of opportunity for implantation. While on chronic support, the hemodynamic profile of patients with continuous-flow ventricular assist devices is unique and remarkably influenced by the hydration status. Optimal management of these patients from the pre-implant phase to the long-term support phase requires a multidisciplinary approach that is similar to that already long validated for organ transplantation.

Low back pain and kidney mobility: local osteopathic fascial manipulation decreases pain perception and improves renal mobility.

OBJECTIVES: a) To calculate and compare a Kidney Mobility Score (KMS) in asymptomatic and Low Back Pain (LBP) individuals through real-time Ultrasound (US) investigation. b) To assess the effect of Osteopathic Fascial Manipulation (OFM), consisting of Still Technique (ST) and Fascial Unwinding (FU), on renal mobility in people with non-specific LBP. c) To evaluate 'if' and 'to what degree' pain perception may vary in patients with LBP, after OFM is applied. METHODS: 101 asymptomatic people (F 30; M 71; mean age 38.9 ± 8) were evaluated by abdominal US screening. The distance between the superior renal pole of the right kidney and the ipsilateral diaphragmatic pillar was calculated in both maximal expiration (RdE) and maximal inspiration (RdI). The mean of the RdE-RdI ratios provided a Kidney Mobility Score (KMS) in the cohort of asymptomatic people. The same procedure was applied to 140 participants (F 66; M 74; mean age 39.3 ± 8) complaining of non-specific LBP: 109 of whom were randomly assigned to the Experimental group and 31 to the Control group. For both groups, a difference of RdE and RdI values was calculated (RD = RdE-RdI), before (RD-T0) and after (RD-T1) treatment was delivered, to assess the effective range of right kidney mobility. EVALUATION: A blind assessment of each patient was carried using US screening. Both groups completed a Short-Form McGill Pain Assessment Questionnaire (SF-MPQ) on the day of recruitment (SF-MPQ T0) as well as on the third day following treatment (SF-MPQ T1). An Osteopathic assessment of the thoraco-lumbo-pelvic region to all the Experimental participants was performed, in order to identify specific areas of major myofascial tension. INTERVENTION: Each individual of the Experimental group received OFM by the same Osteopath who had previously assessed them. A sham-treatment was applied to the Control group for the equivalent amount of time. RESULTS: a) The factorial ANOVA test showed a significant difference (p-value < 0.05) between KMS in asymptomatic individuals (1.92 mm, Std. Dev. 1.14) compared with the findings in patients with LBP (1.52 mm, Std. Dev. 0.79). b) The ANOVA test at repeated measures showed a significant difference (p-value < 0.0001) between pre- to post-RD values of the Experimental group compared with those found in the Control. c) A significant difference (p-value < 0.0001) between pre- to post-SF-MPQ results was found in the Experimental cohort compared with those obtained in the Control. CONCLUSIONS: People with non-specific LBP present with a reduced range of kidney mobility compared to the findings in asymptomatic individuals. Osteopathic manipulation is shown to be an effective manual approach towards improvement of kidney mobility and reduction of pain perception over the short-term, in individuals with non-specific LBP.

Artificial muscle: the human chimera is the future.

Severe heart failure and cerebral stroke are broadly associated with the impairment of muscular function that conventional treatments struggle to restore. New technologies enable the construction of "smart" materials that could be of great help in treating diseases where the main problem is muscle weakness. These materials "behave" similarly to biological systems, because the material directly converts energy, for example electrical energy into movement. The extension and contraction occur silently like in natural muscles. The real challenge is to transfer this amazing technology into devices that restore or replace the mechanical function of failing muscle. Cardiac assist devices based on artificial muscle technology could envelope a weak heart and temporarily improve its systolic function, or, if placed on top of the atrium, restore the atrial kick in chronic atrial fibrillation. Artificial sphincters could be used to treat urinary incontinence after prostatectomy or faecal incontinence associated with stomas. Artificial muscles can restore the ability of patients with facial paralysis due to stroke or nerve injury to blink. Smart materials could be used to construct an artificial oesophagus including peristaltic movement and lower oesophageal sphincter function to replace the diseased oesophagus thereby avoiding the need for laparotomy to mobilise stomach or intestine. In conclusion, in the near future, smart devices will integrate with the human body to fill functional gaps due to organ failure, and so create a human chimera.

Impact of aortic grafts on arterial pressure: a computational fluid dynamics study.

OBJECTIVE: Vascular prostheses currently used in vascular surgery do not have the same mechanical properties as human arteries. This computational study analyses the mechanisms by which grafts, placed in the ascending aorta (proximal) and descending aorta (distal), affect arterial blood pressure. METHODS: A one-dimensional cardiovascular model was developed and adapted to include the graft geometry with in vitro measured mechanical properties. Pressure at the aortic root and haemodynamic parameters were computed and compared for a control, proximal and distal graft case. RESULTS: In comparison to the control case, the proximal graft increased characteristic impedance by 58% versus only 1% change for the distal graft. The proximal and distal graft increased pulse pressure by 21% and 10%, respectively. CONCLUSIONS: The mechanisms underlying pulse pressure increase are different for proximal and distal grafts. For the proximal graft, the primary reason for pulse pressure rise is augmentation of the forward wave, resulting from characteristic impedance increase. For the distal graft, the pulse pressure rise is associated with augmented wave reflections resulting from compliance mismatch. Overall, the proximal aortic graft resulted in greater haemodynamic alterations than the distal graft. Thus, it is likely that patients who receive ascending aorta grafts are more prone to systolic hypertension and therefore deserve closer blood pressure monitoring.

[Selection and preoperative follow-up of heart transplantation candidates in the French part of Switzerland]. / Sélection et suivi prétransplantation des patients candidats à la greffe cardiaque en Suisse romande.

Heart transplantation (HTx) started in 1987 at two university hospitals (CHUV, HUG) in the western part of Switzerland, with 223 HTx performed at the CHUV until December 2010. Between 1987 and 2003, 106 HTx were realized at the HUG resulting in a total of 329 HTx in the western part of Switzerland. After the relocation of organ transplantation activity in the western part of Switzerland in 2003, the surgical part and the early postoperative care of HTx remained limited to the CHUV. However, every other HTx activity are pursued at the two university hospitals (CHUV, HUG). This article summarizes the actual protocols for selection and pre-transplant follow-up of HTx candidates in the western part of Switzerland, permitting a uniform structure of pretransplant follow-up in the western part of Switzerland.

Atrial assist device, a new alternative to lifelong anticoagulation?

OBJECTIVE: Atrial fibrillation is a very common heart arrhythmia, associated with a five-fold increase in the risk of embolic strokes. Treatment strategies encompass palliative drugs or surgical procedures all of which can restore sinus rhythm. Unfortunately, atria often fail to recover their mechanical function and patients therefore require lifelong anticoagulation therapy. A motorless volume displacing device (Atripump) based on artificial muscle technology, positioned on the external surface of atrium could avoid the need of oral anticoagulation and its haemorrhagic complications. An animal study was conducted in order to assess the haemodynamic effects that such a pump could provide. METHODS: Atripump is a dome-shape siliconecoated nitinol actuator sewn on the external surface of the atrium. It is driven by a pacemaker-like control unit. Five non-anticoagulated sheep were selected for this experiment. The right atrium was surgically exposed, the device sutured and connected. Haemodynamic parameters and intracardiac ultrasound (ICUS) data were recorded in each animal and under three conditions; baseline; atrial fibrillation (AF); atripump assisted AF (aaAF). RESULTS: In two animals, after 20 min of AF, small thrombi appeared in the right atrial appendix and were washed out once the pump was turned on. Assistance also enhanced atrial ejection fraction. 31% baseline; 5% during AF; 20% under aaAF. Right atrial systolic surfaces (cm2) were; 5.2 +/- 0.3 baseline; 6.2 +/- 0.1 AF; 5.4 +/- 0.3 aaAF. CONCLUSION: This compact and reliable pump seems to restore the atrial "kick" and prevents embolic events. It could avoid long-term anticoagulation therapy and open new hopes in the care of end-stage heart failure.

A simple way to decompress the left ventricle during venoarterial bypass.

OBJECTIVE: The aim of this investigation was to improve the hemodynamics during venoarterial bypass by remote decompression of the left ventricle (LV). METHODS: Venoarterial bypass was established in 5 bovine experiments (69+/-10 kg) by the transjugular insertion of a self-expanding cannula (smartcanula) with return through a carotid artery. Cardiogenic shock was simulated with ventricular fibrillation induced by an external stimulator. Left ventricular decompression was achieved by switching to transfemoral drainage of the pulmonary artery (PA) with a long self-expanding cannula. RESULTS: Initial pump flow was 4.7+/-0.9 l/min and the aortic pressure accounted for 75+/-21 mmHg. After induction of ventricular fibrillation, the pump flow dropped after 11+/-8 min to 2.5+/-0.1 l/min. Transfemoral decompression increased the pump flow to 5.6+/-0.7 l/min, while the RV pressure decreased from 27+/-9 to 3+/-5 mmHg, the PA pressure decreased from 29+/-7 to 5+/-4 mmHg, the LV pressure decreased from 29+/-6 to 7+/-2 mmHg, and the aortic pressure increased from 31+/-3 to 47+/-11 mmHg. CONCLUSIONS: Remote drainage of the pulmonary artery during venoarterial bypass allows for effective decompression of the left ventricle and provides superior hemodynamics.

[Hybrid treatment of aortic aneurysms]. / Les cures hybrides des lésions anévrismales.

The hybrid treatment of aortic aneurysms is indicated in patients having the ostia of supra aortic or visceral branches taken in to the aneurysm. Indeed, these lesions are not eligible for classic endovascular treatment because the existing endoprostheses cannot provide perfusion of the side branches without inducing major endoleaks. The surgical technique consists of 2 steps: firstly, a by-pass between normal aorta and the major aortic branches involved in the aneurysm is performed to guarantee the perfusion of the organs such as brain, bowel, and after endoprosthesis deployment. Secondly, the endoprosthesis is deployed using the classical technique to isolate the aneurysm. The hybrid approach provides safe and reliable treatment of complex aortic aneurysms with mortality and morbidity rate far below the classical open surgery.

[Stents valves for percutaneous valve replacement]. / Remplacement valvulaire percutané au moyen de stent-valves--une nouvelle approche thérapeutique.

Stents have a long history in traditional valve surgery as both, porcine biological valves as well as pericardial valves are mounted on stents prior to implantation. Recently stent-mounted biological devices have been compressed up to the point, where they can be passed through a catheter. Various routes can be distinguished for implantation: open access, the trans-vascular route in antegrade or retrograde fashion, as well as direct trans-apical or trans-atrial access. Direct access has the potentialforvideo-endoscopic valve replacement. In theory, as well as in the experimental setting, valved stents have been implanted in tricuspid and caval position respectively, as well as in pulmonary, mitral and aortic locations. The largest clinical experience has been achieved in pulmonary position whereas current efforts target the aortic position.

[Cell therapies in cardiology: results from the first randomized clinical trials]. / Thérapie cellulaire en cardiologie: bilan des premiers essais cliniques randomisés.

Following acute myocardial infarction, necrotic cardiac tissue is replaced by scar leading to ventricular remodeling and pump failure. Transplantation of autologous bone marrow-derived cells into the heart, early post-infarct, aims to prevent ventricular remodeling. This strategy has been evaluated in four controlled, randomized clinical trials, which provided mixed results. A transient improvement in ventricular function was observed in one trial, and a modest improvement (the duration of which remains to be determined) in an additional trial, whereas two trials showed negative results. A modest benefit of bone marrow cell transplantation was also observed in patients with chronic ischemic heart disease. Despite mixed results reported so far, cell therapy of heart disease still is in its infancy and has considerable room for improvement.

Intra vascular ultra sound: one more tool to diagnose aorto-duodenal fistula.

The incidence of aorto-enteric fistula in the first 5 years after abdominal aortic replacement ranges from 0.3 to 2%. We present a clinical case in which all conventional diagnostic tools failed to demonstrate the aorto-enteric fistula. A 73 year-old male suffering intermittent episodes of melena without signs and symptoms of infection was repeatedly admitted at our institution. All conventional diagnostic tools failed to show the bleeding source. Precise diagnosis was obtained using intra vascular ultrasound (IVUS). IVUS allowed prompt diagnosis of the aorto-duodenal fistula and opened the way to its endovascular treatment.

[Management of critical limb ischemia]. / Prise en charge de l'ischémie critique des membres inférieurs.

Critical limb ischemia (CLI) is the leading cause of major leg amputation. Diabetes, smoking and end stage renal disease are the main risk factors for CLI. Despite their reduced survival rate, most CLI patients should be treated by surgical or endovascular arterial reconstruction, since amputation rate with conservative treatment alone is as high as 95% at 1 year in surviving patients with tissue loss, and can be reduced to 25% with successful reconstruction. When arterial reconstruction is impossible or fails, spinal cord stimulation also allows to avoid major amputation in up to 75% of precisely selected patients. Timely management and multidisciplinary approach are advised to reduce the risk of major amputation.

[Surgical options for terminal heart failure]. / Options chirurgicates pour l'insuffisance cardiaque terminale.

Terminal heart failure can be the cause or the result of major dysfunctions of the organisms. Although, the outcome of the natural history is the same in both situations, it is of prime importance to differentiate the two, as only heart failure as the primary cause allows for successful mechanical circulatory support as bridge to transplantation or towards recovery. Various objective parameters allow for the establishment of the diagnosis of terminal heart failure despite optimal medical treatment. A cardiac index <2.0 l/min, and a mixed venous oxygen saturation <60%, in combination with progressive renal failure, should trigger a diagnostic work-up in order to identify cardiac defects that can be corrected or to list the patient for transplantation with/without mechanical circulatory support.

Muscular counterpulsation: preliminary results of a non-invasive alternative to intra-aortic balloon pump.

OBJECTIVES: IABP is the most widely used form of temporary cardiac assist and its benefits are well established. We designed an animal study to evaluate a device based on muscular counterpulsation (MCP) that should reproduce the same hemodynamic effects as IABP in a completely non-invasive way. METHODS: Six calves, 60+/-4 kg, divided into 2 groups, in general anaesthesia, equipped with EKG, Swan-Ganz, pressure probe in the femoral artery and flow probe in the left carotid artery, received either IABP through right femoral artery, or muscle counterpulsation (MCP). MCP consists of electrically induced skeletal muscle contraction during early diastole, triggered by EKG and microprocessor controlled by a portable device. For each animal the following parameters were also considered: mean aortic pressure (mAoP), CO, CI, left ventricular stroke work index (LVSWI), systemic vascular resistance (SVR) and mean femoral artery flow (Faf). We did 3 sets of measurements: baseline (BL), after 20 (M20) and 40 (M40) min of cardiac assistance. These measurements have been repeated after 40 min of rest for 3 times. Results are expressed as mean+/-SD. RESULTS: Baseline values: mAoP, 76.51+/-12 mmHg; mCVP, 11.5+/-3 mmHg; CO, 5+/-1 l/min per m(2); LVSWI, 0.77+/-0.2 KJ/m(2); SVR, 1040+/-15 dyns/cm(-5); Faf, 75.5+/-10 ml/min. IABP group: mAoP, 81.1+/-6 mmHg; mCVP, 1+/-0.1 mmHg; CO, 4.5+/-0.7 l/min per m(2); LVSWI, 0.69+/-0.2 KJ/m(2); SVR, 1424+/-8 dyns/cm(-5); Faf, 64.3+/-3 ml/min. MCP group: mAoP, 60.1+/-7 mmHg; mCVP, 23.6+/-2 mmHg; CO, 4.8+/-0.4 l/min per m(2); LVSWI, 0.69+/-0.2 KJ/m(2); SVR, 608+/-25 dyns/cm(-5); Faf, 92.3+/-12 ml/min. CONCLUSIONS: MCP and IABP had the same effects on CO and LVSWI. Moreover, MCP reduced SVR and increased the peripheral circulation without requiring any vascular access nor anticoagulation therapy.

Sutureless videoendoscopic thoracic aorta to iliac artery bypass: the easiest approach to occlusive aorto-iliac diseases.

OBJECTIVE: We designed an animal study to determine the feasibility of videoendoscopic thoracic aorta to iliac artery bypass using a sutureless anastomotic device for proximal anastomosis construction. METHODS: In 12 pigs the descending thoracic aorta was exposed using the thoracoscopic technique. A 4 mm PTFE thin wall graft was used as conduit. The proximal anastomosis was constructed using a mechanical device for sutureless anastomosis inserted through the camera port incision. The prosthesis was passed through the diaphragm in the retroperitoneal space and the distal anastomosis was done with running suture. RESULTS: The operation was successfully completed in 11 animals. One animal died due to hemorrage during anastomosis construction. Mean graft flow was 144 ml/min (range 88-167 mmHg). The angiogram showed no graft kinking or stenosis. Total operative time was 58 min (range 47-68 min). CONCLUSIONS: This approach allows quick and excellent exposure of the entire descending thoracic aorta. The use of the sutureless device to perform the proximal anastomosis dramatically reduces the technical demands of this procedure and could avoid an aortic clamp.

Cross-sectional compliance overestimates arterial compliance because it neglects the axial strain.

A high resolution echo-tracking system permits the calculation of cross-sectional compliance considering vessel diameter variations alone, and assumes that longitudinal movement of the vessel wall due to pulse pressure is negligible. However, using piezoelectric crystals sutured on the adventitia of the vessel wall we demonstrated that arterial length changes up to 5% (mean 2.7%) as a function of pulse pressure. Therefore, cross-sectional compliance seems to provide a limited approximation of the real phenomenon because it neglects axial vessel movement. Axial vessel movement is taken into account when the vessel compliance is calculated according to the principle of continuity of the mass: [equation: see text]. To verify this hypothesis we measured the blood flow gradient through 10 cm long segments of 10 pig carotid arteries (Qin - Qout) and divided it for the derivative of blood pressure over a given time (deltaP/deltat). For the same vessels, we calculated the cross-sectional compliance (CC) using the echo-tracking system (NIUS 02). We found a CC of (5.91 +/- 0.4) x 10(-7) micro m(2)/mm Hg and a segmental carotid compliance or dynamic compliance (C(d)) of (6.21 +/- 0.2) x 10(-8) micro m(3)/mm Hg. The impact of axial strain in calculations of compliance results in a dynamic compliance, which is one order of magnitude smaller than traditionally calculated arterial compliance.