Relocation of patients after cardiac surgery: is it worth the effort?

BACKGROUND: Fast-track protocols may facilitate early patient discharge from the site of surgery through the implementation of more expedient pathways. However, costs may merely be shifted towards other parts of the health care system. We aimed to investigate the consequence of patient transfers on overall hospitalisation, follow-up and readmission rate after cardiac surgery. METHODS: A single-centre descriptive cohort study using prospectively entered registry data. The study included 4,515 patients who underwent cardiac surgery at Aarhus University Hospital during the period 1 April 2006 to 31 December 2012. Patients were grouped and analysed based on type of discharge: Directly from site of surgery or after transfer to a regional hospital. The cohort was obtained from the Western Denmark Heart Registry and matched to the Danish National Hospital Register. RESULTS: Median overall length of stay was 9 days (7.0;14.4). Transferred patients had longer length of stay, median difference of 2.0 days, p < 0.001. Time to first outpatient consultation was 41(30;58) days in transferred patients vs. 45(29;74) days, p < 0.001. 18.6% was readmitted within 30 days. Mean time to readmission was 18.4 ± 6.4 days. Median length of readmission was 3(1,6) days. There was no difference in readmissions between groups. Leading cause of readmission was cardiovascular disease with 48%. CONCLUSION: Transfer of patients does not overtly reduce health care costs, but overall LOS and time to first outpatient consultation are substantially longer in patients transferred to secondary hospitals than in patients discharged directly. Readmission rate is high during the month after surgery, but with no difference between groups.

Effects of levosimendan in patients with left ventricular hypertrophy undergoing aortic valve replacement.

BACKGROUND: Left ventricular hypertrophy is associated with adverse outcomes, including death, during cardiac surgery. This may be facilitated by an increased oxygen demand and diastolic dysfunction. Levosimendan augments haemodynamics without further oxygen consumption and improves echocardiographic indices of diastolic dysfunction. This study aimed to describe the haemodynamic effects of short-term pre- and intra-operative levosimendan infusion including advanced echocardiographic measures of diastolic and systolic heart function. METHODS: The study was randomised, double-blinded and placebo-controlled performed at a single-centre university hospital. Patients with left ventricular hypertrophy and ejection fraction > 45% scheduled for single procedure aortic valve replacement were included and randomised to infusion of either levosimendan 0.1 µg/kg/min or placebo from 4 h before anaesthesia to the end of surgery. Outcome measures were echocardiographic indices of left ventricular diastolic function: E/e' (primary endpoint), e', e'/a' and indices of systolic function: longitudinal strain, ejection fraction and s'. Patients were followed until 6 months after surgery. In addition, invasive haemodynamic measures were obtained perioperatively. RESULTS: The trial was prematurely terminated due to an overall high incidence of post-operative atrial fibrillation (15/20, P = 0.002) after inclusion of 20 patients. The relative decrease in perioperative cardiac index was lower (P = 0.016) in the levosimendan group. There was no difference in E/e', and similar results were found for all measures of systolic function. CONCLUSION: Short-term levosimendan caused a transient relative increase in cardiac index, but no effect was seen on the first post-operative day and up to 6 months post-operatively with indices of systolic and diastolic heart function.

High thoracic epidural analgesia decreases stress hyperglycemia and insulin need in cardiac surgery patients.

OBJECTIVE: Assuming that high thoracic epidural analgesia (HTEA) with the sympathetic block might decrease postoperative blood glucose (BG) level and reduce the need of insulin, the aim was to evaluate the effect of HTEA on the BG level and insulin requirement in patients undergoing cardiac surgery. MATERIALS AND METHODS: Forty-two low-risk patients age 65-79 years scheduled for elective coronary artery bypass grafting with or without aortic valve replacement were randomised to receive HTEA as supplement for general anaesthesia. BG and lactate were measured before and after cardiopulmonary bypass and postoperatively at least every 3 h together with administration of insulin. Postoperative pain was evaluated 30 min, 2, 4 and 6 h after extubation, and before discharge from the intensive care unit. RESULTS: Overall BG levels showed great variation over time (P < 0.001). No statistically significant difference was found in perioperative BG, but postoperative lower BG levels were found in HTEA patients (P = 0.042). The number of patients not receiving insulin in postoperative period was significantly higher in HTEA group (9 vs. 2, P = 0.032). No differences were seen in lactate levels. Patients in the HTEA group had significant lower pain scores (P < 0.001). CONCLUSION: HTEA preserves glucose metabolism better and leads to a lesser degree of 'stress hyperglycaemia' in cardiac surgery patients.

Mesenchymal stem cells in oral reconstructive surgery: a systematic review of the literature.

This study evaluated clinical outcomes following intraoperative use of adult mesenchymal stem cells (MSCs) in various oral reconstructive procedures. PubMed was searched without language restrictions from 2000 to 2011 using the search words stem cell, oral surgery, tissue engineering, sinus lift, bone regeneration and combinations of these. Inclusion criteria were intraoperative use of MSCs in the study design. Reference lists of the articles found were searched for other related studies. Eighteen clinical trials using MSCs for sinus augmentation were found: five case reports on the repair of large bony defects and six studies on ridge augmentation and healing of alveolar sockets after third molar extraction. The findings suggest that MSCs are capable of producing in vivo bone, re-establishing lost tissue and facilitating placement of dental implants. Use of MSCs would reduce patient morbidity because of a less stressful harvesting technique than that of autogenous bone. The majority of clinical trials indicate that MSCs can produce bone in vivo. However, a satisfactory outcome was not seen in all studies, and due to the diversity of study designs, a 'golden approach' cannot be determined. Before use of MSCs can be considered as a first-choice treatment, more predictable outcomes and better long-term prognoses need to be established. Conventional bone grafting remains the gold standard.

Power dependence of supercontinuum noise in uniform and tapered PCFs.

We experimentally investigate the noise properties of picosecond supercontinuum spectra generated at different power levels in uniform and tapered photonic crystal fibers. We show that the noise at the spectral edges of the generated supercontinuum is at a constant level independent on the pump power in both tapered and uniform fibers. At high input power the spectral bandwidth is limited by the infrared loss edge, this however has no effect on the noise properties.

Deep-blue supercontinnum sources with optimum taper profiles--verification of GAM.

We use an asymmetric 2 m draw-tower photonic crystal fiber taper to demonstrate that the taper profile needs careful optimisation if you want to develop a supercontinuum light source with as much power as possible in the blue edge of the spectrum. In particular we show, that for a given taper length, the downtapering should be as long as possible. We argue how this may be explained by the concept of group-acceleration mismatch (GAM) and we confirm the results using conventional symmetrical short tapers made on a taper station, which have varying downtapering lengths.

Agreement between cardiac outputs by four-dimensional echocardiography and thermodilution method is poor.

OBJECTIVE: The objective of the study was to determine the agreement of cardiac output (CO) measured by four-dimensional echocardiography (4D echo) to simultaneously obtain CO from pulmonary artery catheter (PAC) using thermodilution technique. MATERIALS AND METHODS: Sixty-three comparable readings from 27 patients scheduled for elective coronary artery bypass were included. All echocardiographic measurements were obtained by one experienced echocardiographer. All echo images were analyzed independently and blinded from PAC-obtained measurements. Analysis was primarily done by Bland and Altman plot. The collected data were further controlled for interobserver bias and image quality. RESULTS: Differences in CO measurements increased with higher CO, hence values were logarithmically transformed. On the logaritmic scale, the 4D echo underestimated CO by 0.37 l/min compared with PAC, indicating that PAC measurements were 1.45 times higher than the 4D echo (95% confidence interval 1.32-1.52) and limits of agreement 0.97-2.14). The interobserver bias of 4D echo measurement analysis was 0.29 l/min (95% confidence interval 0.16-0.42) and limits of agreement -0.8-1.38). No difference was seen in image quality between comparisons with good agreement compared with comparisons with poor agreement. CONCLUSION: The agreement between COs by 4D echo and standard PAC thermodilution technique was poor. 4D echo underestimates CO as compared with PAC. This is most likely caused by the analysis software or low frame rate inherent to the technique.

Variation in use of peroperative inotropic support therapy in cardiac surgery: time for reflection?

BACKGROUND: There is no well-established evidence-based clinical guidelines on the most appropriate use of peroperative inotropic support in cardiac surgery. We aimed to identify patient- and procedure-related factors associated with the use of peroperative inotropic support and to estimate physician-level variation. METHODS: A population-based study using data from the Western Denmark Heart Registry on 3585 consecutive cardiac surgery cases from three university hospitals. Inotropic support was defined as infusion of inotropic drugs or nor epinephrine at the separation from cardiopulmonary bypass. Poisson's regression modelling was used to determine predictors of inotropic support and to compare use of high-dose inotropic support among experienced cardiac anaesthesiologists. RESULTS: We identified a range of factors that were independently associated with an increased use of inotropic support therapy including pre-operative left ventricular dysfunction, pre-operative renal dysfunction, complex procedures, prior cardiac surgery, emergency surgery, pre-operative pulmonary hypertension, critical pre-operative state, extended extra corporal circulation-time and female gender. Further, we found substantial variation in use of inotropic support both at hospital- and at physician-level. The adjusted odds ratio of high-intensity inotropic support varied significantly at physician level from 2.3 [95% confidence interval (CI) 1.83-2.71] to 0.3 (95% CI 0.15-0.61) when the individual physicians were compared with the rest. CONCLUSION: The use of inotropic support during cardiac surgery is associated with the pre-operative state of the patient, as well as type of surgery. However, the present study indicates that use of peroperative inotropic support is also highly dependent on physician's preferences, indicating the need for an evidence-based approach when initiating inotropic therapy in cardiac surgery.

Sufentanil preserves hemodynamics and left ventricular function in patients with ischemic heart disease.

OBJECTIVE: Sufentanil has been reported to provide stable hemodynamics similar to other opioids. However, it has not been reliably established whether this stability can be attributed only to Sufentanil and translates into fully preserved left ventricular (LV) function. The purpose of this study was to evaluate the effect of Sufentanil on hemodynamics and LV systolic and diastolic function using invasive monitoring and echocardiography in patients with ischemic heart disease. METHODS: Prospective observational study of thirty patients acting as their own control undergoing echocardiographic imaging before and after bolus Sufentanil 1.5-2.0 µg/kg. Full invasive hemodynamic monitoring was established before Sufentanil administration. Global LV systolic function was evaluated with a global longitudinal peak systolic strain (GLPSS) by speckle tracking ultrasound; systolic displacement by tissue tracking (TT) and diastolic function was evaluated using Doppler tissue imaging and pulse wave Doppler. RESULTS: Hemodynamic monitoring showed a minor decline in systolic blood pressure from 159 to 154 mmHg (P=0.046). No changes were observed in the cardiac index, stroke volume index and heart rate. An unchanged TT score index (9.9 vs. 10.2 mm, P=0.428) and GLPSS (14.3 vs. 14.5%, P=0.658) indicated preserved LV global systolic function and unchanged E'/A' (0.95 vs. 0.89, P=0.110) and E/E' ratio (15.4 vs. 14.9, P=0.612) indicated unchanged diastolic function. CONCLUSION: Sufentanil preserves hemodynamic parameters as well as echocardiographic indices of LV systolic and diastolic function in patients with ischemic heart disease (IHD).

Ketamine reduce left ventricular systolic and diastolic function in patients with ischaemic heart disease.

OBJECTIVE: Ketamine may be followed by a general increase in haemodynamics and oxygen consumption, which may be of concern in patients with ischaemic heart disease. The purpose of this study was to evaluate the effect of ketamine on left ventricular (LV) systolic and diastolic function by different modalities of echocardiography and tissue Doppler imaging in patients with ischaemic heart disease. METHODS AND RESULTS: Prospective observational study of 11 patients acting as own control based on echocardiographic imaging before and after bolus ketamine 0.5 mg/kg. Simpson's 2 D-volumetric method was used to quantify left ventricular volume and ejection fraction. General global LV deformation was assessed by Speckle tracking ultrasound, systolic LV longitudinal displacement was assessed by Tissue Tracking score index and the diastolic function was evaluated from changes in early-(E') and atrial (A') peak velocities during diastole. Average heart rate (34%) and blood pressure (35%) increased significantly after ketamine (P<0.0001). Mean tissue tracking score index decreased from 11.2 ± 2.3 to 8.3 ± 2.6 (P=0.005) and Global Speckle tracking 2D strain from 17.7 ± 2.7 to 13.7 ± 3.6 (P=0.0014) indicating a decrease in LV global systolic function. The E'/A' ratio decreased from 1.11 ± 0.43 to 0.81 ± 0.46 (P=0.044) indicating impaired relaxation. CONCLUSION: Different modalities of echocardiography in combination with tissue Doppler indicate both diminished systolic and diastolic function after ketamine administration in patients with ischaemic heart disease.

7-cell core hollow-core photonic crystal fibers with low loss in the spectral region around 2 microm.

Several 7 cell core hollow-core photonic crystal fibers with bandgaps in the spectral range of 1.4 microm to 2.3 microm have been fabricated. The transmission loss follows the approximately lambda(-3) dependency previously reported, with a minimum measured loss of 9.5 dB/km at 1.99 microm. One fiber with a transmission loss of 26 dB/km at 2.3 microm is reported, which is significantly lower than the transmission loss of solid silica fibers at this wavelength.

High thoracic epidural analgesia improves left ventricular function in patients with ischemic heart.

BACKGROUND: In patients with ischemic heart disease, high thoracic epidural analgesia (HTEA) has been proposed to improve myocardial function. Tissue Doppler Imaging (TDI) is a tool for quantitative determination of myocardial systolic and diastolic velocities and a derivative of TDI is tissue tracking (TT), which allows quantitative assessment of myocardial systolic longitudinal displacement during systole. The purpose of this study was to evaluate the effect of thoracic epidural analgesia on left ventricular (LV) systolic and diastolic function by means of two-dimensional (2D) echocardiography and TDI in patients with ischemic heart disease. METHODS: The effect of a high epidural block (at least Th1-Th5) on myocardial function in patients (N=15) with ischemic heart disease was evaluated. Simpson's 2D volumetric method was used to quantify LV volume and ejection fraction. Systolic longitudinal displacement was assessed by the TT score index and the diastolic function was evaluated from changes in early (E'') and atrial (A'') peak velocities during diastole. RESULTS: After HTEA, 2D measures of left ventricle function improved significantly together with the mean TT score index [from 5.87 +/- 1.53 to 6.86 +/- 1.38 (P<0.0003)], reflecting an increase in LV global systolic function and longitudinal systolic displacement. The E''/A'' ratio increased from 0.75 +/- 0.27 to 1.09 +/- 0.32 (P=0.0026), indicating improved relaxation. CONCLUSION: A 2D-echocardiography in combination with TDI indicates both improved systolic and diastolic function after HTEA in patients with ischemic heart disease.

Single-polarization ultra-large-mode-area Yb-doped photonic crystal fiber.

We report on an ytterbium-doped single-transverse-mode rod-type photonic crystal fiber that combines the advantages of low nonlinearity and intrinsic polarization stability. The mode-field-area of the fundamental mode is as large as 2300 microm(2). An output power of up to 163 W with a degree of polarization better than 85% has been extracted from a simple fiber laser setup without any additional polarizing element within the cavity than the fiber itself. The beam quality has been characterized by a M(2) value of 1.2. The single-polarization window ranges from 1030 to 1080 nm, hence possesses an excellent overlap with the gain profile of ytterbium-doped silica fibers. To the best of our knowledge this fiber design has the largest mode-field-diameter ever reported for polarizing or even polarization maintaining rare-earth-doped double-clad fibers.

Cardiac surgery patients present considerable variation in pre-operative hemodynamic variables.

BACKGROUND: It is essential to control hemodynamics in cardiac surgery. Patients are often monitored extensively in order to optimize hemodynamic performance. However, pre-operative values are normally unknown. Furthermore, hemodynamic goals may seem arbitrary and the lack of an evidence-based consensus may lead to both under- and over-treatment. The aim of this study was to evaluate the variables most commonly used for hemodynamic guidance in the post-operative period. METHODS: Ten patients scheduled for elective cardiac surgery were followed with invasive hemodynamic monitoring the night before surgery. All data were recorded automatically and electronically. RESULTS: We found considerable inter-patient differences and intra-patient variation. The greatest intra-patient variation was found in the cardiac index (CI), ranging from 1.9 to 5.3 l/min/m(2). Four patients had periodic CI <2.4 l/min/m(2). Eight patients showed SpO2 values < or =92, four of them in more than 15% of the observations. Six patients had an SvO2 <70% in more than 40% of the observations and two an SvO2 < 64% in more than 20% of the observations. CONCLUSIONS: This study is unique because hemodynamic reference data in cardiac surgery patients have not been published previously. The intra-patient variations were unexpectedly high in most hemodynamic variables and demonstrate the difficulties of using hemodynamic parameters as a guidance for treatment and indicate that goal-oriented therapy using currently accepted values may result in over-treatment in some patients.

Autotransplantation of premolars: does surgeon experience matter?

Autotransplantation of premolars is a well-established method to rehabilitate aplasia of premolars. Nevertheless, with the introduction of titanium implants, not all surgical units offer this procedure. The aim of this study was to examine the predictability of autotransplantation of premolars on orthodontic indication as suggested by Andreasen et al., when performed by surgeons with or without prior experience of this procedure. A prospective protocol was implemented in 2001. All patients treated with autotransplantation of premolars during the years 2001-2015 were recalled to evaluate the long-term status of the teeth. The state of root development, need for endodontic treatment, presence of an apical pathology or ankylosis, and tooth loss were recorded. The results were divided into two groups according to the surgeon's experience: senior surgeons with prior training and experience in the procedure and junior surgeons without prior experience. A total of 89 teeth (66 patients) were treated. The mean observation time was 10.1 years (range 1.0-15.1 years). The long-term survival rate was 95%. No statistically significant difference between the results of the two groups of surgeons was found. Autotransplantation of premolars on orthodontic indication could be adopted successfully in the hospital setting regardless of surgeon experience.

High-power rod-type photonic crystal fiber laser.

We report on a novel ytterbium-doped fiber design that combines the advantages of rod and fiber gain media. The fiber design has outer dimensions of a rod laser, meaning a diameter in the range of a few millimeters and a length of just a few tens of centimeters, and includes two important waveguide structures, one for pump radiation and one for laser radiation. We obtained 120-W output power in single-mode beam quality from a 48-cm-long fiber cane that corresponds to an extracted power of 250 W/m. The fiber has significantly reduced nonlinearity, which therefore allows for scalability in the performance of a high-peak-power fiber laser and amplifier system.

Design, synthesis, and pharmacological evaluation of thapsigargin analogues for targeting apoptosis to prostatic cancer cells.

A series of thapsigargin (TG) analogues, containing an amino acid applicable for conjugation to a peptide specifically cleaved by prostate-specific antigen (PSA), has been prepared to develop the drug-moiety of prodrugs for treatment of prostatic cancer. The analogues were synthesized by converting TG into O-8-debutanoylthapsigargin (DBTG) and esterifying O-8 of DBTG with various amino acid linkers. The compounds were evaluated for their ability to elevate the cytosolic Ca(2+) concentration ([Ca(2+)](i)) in TSU-Pr1 cells, their ability to inhibit the rabbit skeletal muscle SERCA pump, and their ability to induce apoptosis in TSU-Pr1 human prostatic cancer cells. The activity of analogues, in which DBTG were esterified with omega-amino acids [HOOC(CH(2))(n)()NH(2), n = 5-7, 10, 11], increased with the linker length. Analogues with 3-[4-(L-leucinoylamino)phenyl]propanoyl, 6-(L-leucinoylamino)hexanoyl, and 12-(L-serinoylamino)dodecanoyl were considerably less active than TG, and analogues with 12-(L-alaninoylamino)dodecanoyl and 12-(L-phenylalaninoylamino)dodecanoyl were almost as active as TG. The 12-(L-leucinoylamino)dodecanoyl gave an analogue equipotent with TG, making this compound promising as the drug-moiety of a PSA sensitive prodrug of TG.

Polarization maintaining large mode area photonic crystal fiber.

We report on a polarization maintaining large mode area photonic crystal fiber. Unlike, previous work on polarization maintaining photonic crystal fibers, birefringence is introduced using stress applying parts. This has allowed us to realize fibers, which are both single mode at any wavelength and have a practically constant birefringence for any wavelength. The fibers presented in this work have mode field diameters from about 4 to 6.5 micron, and exhibit a typical birefringence of 1.510(-4).

High-power air-clad large-mode-area photonic crystal fiber laser.

We report on a 2.3 m long air-clad ytterbium-doped large-modearea photonic crystal fiber laser generating up to 80 W output power with a slope efficiency of 78%. Single transverse mode operation is achieved with a mode-field area of 350 microm2. No thermo-optical limitations are observed at the extracted ~35W/m, therefore such fibers allow scaling to even higher powers.

Low-nonlinearity single-transverse-mode ytterbium-doped photonic crystal fiber amplifier.

We report on an air-clad large-core single-transverse-mode ytterbium-doped photonic crystal fiber with a mode-field-diameter of 35 microm, corresponding to a mode-field-area of ~1000 microm(2). In a first experiment this fiber is used to amplify 10-ps pulses to a peak power of 60 kW without significant spectral broadening due to self-phase modulation allowing for the frequency up-conversion of these pulses using narrow-bandwidth phase matched nonlinear crystals.