Alteration of inflammatory response by shock wave therapy leads to reduced calcification of decellularized aortic xenografts in mice†.

OBJECTIVES: Tissue-engineered xenografts represent a promising treatment option in heart valve disease. However, inflammatory response leading to graft failure and incomplete in vitro repopulation with recipient cells remain challenging. Shock waves (SWs) were shown to modulate inflammation and to enhance re-epithelialization. We therefore aimed to investigate whether SWs could serve as a feasible adjunct to tissue engineering. METHODS: Porcine aortic pieces were decellularized using sodium deoxycholate and sodium dodecylsulphate and implanted subcutaneously into C57BL/6 mice (n = 6 per group). The treatment (shock wave therapy, SWT) group received SWs (0.1 mJ/mm(2), 500 impulses, 5 Hz) for modulation of inflammatory response directly after implantation; control animals remained untreated (CTR). Grafts were harvested 72 h and 3 weeks after implantation and analysed for inflammatory cytokines, macrophage infiltration and polarization, osteoclastic activity and calcification. Transmission electron microscopy (TEM) was performed. Endothelial cells (ECs) were treated with SWs and analysed for macrophage regulatory cytokines. In an ex vivo experimental set-up, decellularized porcine aortic valve conduits were reseeded with ECs with and without SWT (0.1 mJ/mm(2), 300 impulses, 3 Hz), fibroblasts as well as peripheral blood mononuclear cells (all human) and tested in a pulsatile flow perfusion system for cell coverage. RESULTS: Treated ECs showed an increase of macrophage migration inhibitory factor and macrophage inflammatory protein 1ß, whereas CD40 ligand and complement component C5/C5a were decreased. Subcutaneously implanted grafts showed increased mRNA levels of tumour necrosis factor α and interleukin 6 in the treatment group. Enhanced repopulation with recipient cells could be observed after SWT. Augmented macrophage infiltration and increased polarization towards M2 macrophages was observed in treated animals. Enhanced recruitment of osteoclastic cells in proximity to calcified tissue was found after SWT. Consequently, SWT resulted in decreased areas of calcification in treated animals. The reseeding experiment revealed that fibroblasts showed the best coverage compared with other cell types. Moreover, SW-treated ECs exhibited enhanced repopulation compared with untreated controls. CONCLUSIONS: SWs reduce the calcification of subcutaneously implanted decellularized xenografts via the modulation of the acute macrophage-mediated inflammatory response and improves the in vitro repopulation of decellularized grafts. It may therefore serve as a feasible adjunct to heart valve tissue engineering.

Simple adaptations of surgical technique to critically reduce the risk of postoperative sternal complications in patients receiving bilateral internal thoracic arteries.

OBJECTIVES: Limited blood supply to the thoracic chest wall is a known risk factor for sternal wound complications after CABG. Therefore, bilateral internal thoracic arteries are still rarely utilized despite their proven superior graft patency. The aim of our study was to analyse whether modification of the surgical technique is able to limit the risk of sternal wound complications in patients receiving bilateral internal thoracic artery grafting. METHODS: All 418 non-emergent CABG patients receiving bilateral internal thoracic artery CABG procedures (BITA) from January 2001 to January 2012 were analysed for sternal wound complications. Surgical technique together with known risk factors and relevant comorbidity were analysed for their effect on the occurrence of sternal wound complications by means of multivariate logistic regression analysis. RESULTS: Sternal wound complications occurred in 25 patients (5.9%), with a sternal dehiscence rate of 2.4% (10 patients). In multivariate analysis, diabetes (odds ratio [OR]: 4.8, 95% CI: 1.9-11.7, P=0.001), but not obesity (OR: 1.6, 95% CI: 0.7-4.2, P=0.28) or chronic obstructive pulmonary disease (OR: 2.2, 95% CI: 0.87-5.6, P=0.1) was a relevant comorbid condition for sternal complications. Skeletonization of ITA grafts (OR: 0.17, 95% CI: 0.06-0.5, P=0.001) and the augmented use of sternal wires (OR: 0.24, 95% CI: 0.06-0.95, P=0.04) were highly effective in preventing sternal complications. The use of platelet-enriched-fibrin glue (PRF) sealant, however, was associated with more superficial sternal infections (OR: 3.7, 95% CI: 1.3-10.5, P=0.02). CONCLUSIONS: Adjusted for common risk factors, skeletonization of BITA grafts together with augmented sternal wires is effective in preventing sternal complications. The use of PRF sealant, however, increased the risk for superficial wound complications.

Second internal thoracic artery versus radial artery in coronary artery bypass grafting: a long-term, propensity score-matched follow-up study.

BACKGROUND: The best second arterial conduit for multiple arterial revascularization (MAR) is still a matter of debate. Previous studies on the benefit of either using the radial artery (RA) or the right internal thoracic artery (RITA) in coronary artery bypass grafting are not conclusive. The aim of our study was to compare the perioperative and long-term outcome of either RA or RITA grafts as second conduits for MAR. METHODS AND RESULTS: A consecutive series of 1001 patients undergoing first nonemergent coronary artery bypass grafting receiving either RA or RITA as second graft for MAR between 2001 and 2010 were studied. There were 277 patients receiving a RITA and 724 patients receiving a RA in addition to a left internal thoracic artery (LITA). Concomitant saphenous vein grafts (SVG) were grafted in addition as necessary. Propensity score-matched analysis was performed to compare the 2 groups, bilateral ITA±SVG (BITA±SVG group) and the LITA+RA±SVG group relative to overall survival and major adverse cardiac and cerebrovascular events-free survival. Hazard ratios and their 95% confidence intervals were estimated by COX regression stratified on matched pairs. The incidence of perioperative major adverse cardiac and cerebrovascular events was significantly lower in the BITA±SVG group (1.4% versus 7.6%, P<0.001). Overall survival (hazard ratio 0.23; 95% confidence interval 0.066-0.81; P=0.022) and major adverse cardiac and cerebrovascular events-free survival (hazard ratio 0.18; 95% confidence interval 0.08-0.42; P<0.001) were significantly better in the BITA±SVG group compared to the LITA+RA±SVG group. CONCLUSIONS: The results of our study provide strong evidence for the superiority of a RITA graft compared to RA as a second conduit in MAR.

Mediastinal liposarcoma.

A 64-year-old male underwent surgical resection of a large liposarcoma of the mediastinum. The management of this unusual tumor is the subject of this case report.

Propensity score-matched analysis of aortic valve replacement by mini-thoracotomy.

BACKGROUND AND AIM OF THE STUDY: Although minimally invasive aortic valve replacement (MIAVR) through an anterolateral mini-thoracotomy has been shown to reduce surgical trauma, the technique is utilized only at a few selected heart surgery centers. The study aim was to demonstrate the implementation of a MIAVR program at the Innsbruck Medical University, Austria. METHODS: Between October 2006 and January 2009, a total of 315 patients underwent elective isolated aortic valve replacement (AVR). Of these patients, 87 (27.6%) received MIAVR, while the remainder (n = 228) underwent 'conventional' AVR by full sternotomy. In the MIAVR group, 76 patients (87%) were cannulated via the femoral artery. The mean EuroSCORE was 5.7 +/- 2.2 in the MIAVR group, and 6.7 +/- 2.9 in the AVR group (p < 0.001). Propensity score matching was used to reduce the impact of treatment selection in the comparison of MIAVR with conventional AVR. The propensity score was used to yield two matched groups by means of a 1:1 sample matching. RESULTS: The total operative, cardiopulmonary bypass and aortic cross-clamp times were significantly longer in the MIAVR group compared to the matched AVR group. The actuarial one-year survival was 96% in the MIAVR group, and 98% in the propensity-matched AVR group (p = 0.57). Reoperation due to bleeding was necessary in 4.6% of the MIAVR group (four patients, three by mini-thoracotomy) compared to 5.7% in the matched AVR group (n = 5; p = 0.38). A total of six MIAVR patients (6.9%) had complications from the cannulated groin, predominantly lymphatic fistula formation. Additionally, there was a trend towards a higher rate of renal insufficiency in the MIAVR group (p = 0.07). CONCLUSION: MIAVR can be safely implemented as routine cardiac surgery procedure, although the operative times are significantly longer. The early postoperative outcome was equal to that of the sternotomy approach, but postoperative complications were predominantly associated with femoral cannulation.

A passive magnetically and hydrodynamically suspended rotary blood pump.

A combined hydrodynamic-magnetic bearing allows the design of rotary blood pumps that are not encumbered with mechanical bearings and magnets requiring sensors or electrical power. However, such pumps have so far needed very small and accurately manufactured gaps between rotor and housing to assure effective hydromagnetic bearing behavior. In order to use this concept in disposable pump heads, a design that allows larger rotor-housing gaps, and thus larger manufacturing tolerances, is needed. A pump with passive magnetic bearings and a gap between rotor and housing in the range of 0.5 mm was designed. Numerical simulations were performed to optimize the rotor geometry at low levels of shear stress. An experimental test stand was used to find a range of speeds and gap settings that resulted in low levels of vibration and useful pressure-flow relationships. Three different rotor geometries were tested using a viscosity-adjusted test fluid. Blood damage tests were conducted within the desirable range of speeds and gap settings. In this study stable pump performance was demonstrated at total gap widths between 0.3 and 0.7 mm at flows of 0-10 L/min, with afterloads up to 230 mm Hg. Best performance was achieved with rotors sliding on a fluid pillow between the rotor and the outer housing at a gap distance of 50 to 250 microm. The inner gap distance, between the rotor and the inner housing, could be as great as 500 microm. Hemolysis tests on the prototype within the chosen operating range showed lower values (NIH = 0.0029 +/- 0.0012 g/100 L) than the Biomedicus BP-80 pump (NIH = 0.0033 +/- 0.0011 g/100 L). In conclusion, it is possible to build rotary blood pumps with passive hydromagnetic bearings that have large gaps between their rotors and housings. Rotor behavior is sensitive to the position of the permanent magnetic drive unit. To minimize vibration and blood damage, the fluid gaps and the rotational speed have to be adjusted according to the desired operating point of the pump. Further study is needed to optimize the magnetic drive unit and to ascertain its ability to withstand inertial loads imposed by sudden movements and external shock.

The accuracy of the Vigileo/FloTrac continuous cardiac output monitor.

OBJECTIVE: The Vigileo/FloTrac system (software version 1.01; Edwards Lifesciences, Irvine, CA) determines cardiac output, without calibration, by analysis of the arterial pulse wave. To assess the accuracy of the Vigileo/FloTrac system, it was compared with the pulmonary artery catheter bolus thermodilution method as the current standard method. The study design was prospective and observer blinded. SETTING: A single university hospital. PARTICIPANTS: Thirty elective coronary artery bypass graft surgery patients. No special interventions were done to the participants. MEASUREMENTS AND MAIN RESULTS: After approval by the ethics committee and with written informed consent, synchronized measurements using both methods were made at 7 predefined time points, intraoperatively and postoperatively, producing 192 data pairs for evaluation. The statistical evaluation was performed by using the Bland-Altman method of analysis. In addition, a +/-20% and +/-30% deviation from the pulmonary artery catheter were evaluated (20% criteria and 30% criteria). In total, 46% of measurements did not fulfill the 20% criteria; 26% were outside the 30% limits. The Bland-Altman analysis for all time points showed that 95% of all differences between both methods were within a range between -2.2 and +3.1 L/min. Regression analysis revealed low correlation values at all time points. CONCLUSION: The described deviation from the standard must be regarded according to the user's needs. Considering the 30% limits of agreement, the Vigileo system (version 1.01) seems sufficiently accurate; applying the 20% criteria, it is not.

Robotic technology-probably a safe tool for development of completely endoscopic coronary revascularization procedures.

BACKGROUND: : Totally endoscopic coronary artery bypass grafting (TECAB) requires telemanipulation technologies because attempts using conventional thoracoscopic instrumentation have completely failed. These complex operations require individual and team learning curves and necessitate a stepwise approach. The aim of this study is to assess risk adjusted outcome in robotically assisted coronary artery bypass grafting (CABG) after the first 6 years of application. METHODS: : From 2001 to 2007, 177 CABG procedures were performed using the da Vinci system. A low risk patient population [age 59 (31-76) years, EuroSCORE 1 (0-7)] was treated. The following procedures were carried out: endoscopic internal mammary artery takedown in minimally invasive direct coronary artery bypass, Off-pump coronary artery bypass, and CABG (n = 26); robotic suturing of left internal mammary artery to left anterior descending artery anastomoses through sternotomy (n = 32); TECAB on the arrested heart (n = 108); TECAB on the beating heart (n = 11). RESULTS: : There was no hospital mortality, and cumulative risk adjusted mortality plots showed that 2.76 predicted events did not occur. Given 177 event free procedures Clopper Pearson estimations revealed a 95% confidence interval between 0.0% and 2.3% for perioperative mortality. CONCLUSIONS: : Introduction of robotic TECAB grafting appears to meet current CABG safety standards. Initial application in low risk patients and a stepwise approach towards completely endoscopic versions of the operation are worthwhile. Despite a high grade of innovation and despite learning curves, perioperative mortality may be lower than predicted.

Evaluation of cardiac scoring models for an Austrian cardiac register.

The Austrian Health 2006 Structural Plan of 28 June 2006 requires that reference centres for heart surgery 'participate in result-quality registers (e.g. cardiac registers)'. The aim of the present study was to identify a suitable scoring model for the Austrian register during the run-up to its creation. During the period from November 2004 to December 2005 a survey was done of the actual situation, the organisational and economic possibilities, and the requirements of all Austrian heart centres. General and also specific Austrian basic conditions were defined. Scoring models were then classified and evaluated. The characteristics 'national and international comparability', the associated 'distribution of the scoring system' and 'detailed scientific discussion of the applicability' were found as the main criteria for selection. Economic aspects such as survey and analysis costs, and the everyday practicability of gathering data in the actual situation revealed by the survey, were also included in the evaluation framework. It could be demonstrated that under the given circumstances, the EuroSCORE represented the suitable predictive model.

Does gender affect outcome of cardiac surgery in octogenarians?

The long-term results of cardiac surgery in 212 consecutive octogenarians (116 men, 96 women) were reviewed retrospectively. Preoperative functional status, Euroscore, and the incidences of hypertension and chronic obstructive pulmonary disease were similar in both sexes. Women had more diabetes mellitus (45% versus 25%; p < 0.05) but less renal dysfunction (16% versus 29%; p < 0.05). Men required emergency procedures more frequently (p < 0.05). Women underwent complete revascularization more often and had more arterial grafts. Hospital mortality was similar (11.5% in women versus 12.9% in men), but women had more complications (76% versus 64%), longer convalescence (24.3 versus 18.5 days), fewer psychiatric disorders (14% versus 23%) and less heart block (9% versus 19%). Men had a slightly better outcome in terms of functional class and Euroqol score during follow-up of up to 114 months. Median survival was longer in women (3.15 versus 2.96 years) but 1-, 3-, and 5-year survival rates and late deaths were similar. Outcomes appear to be equitable for both sexes among octogenarians.