Imaging for trans-catheter pulmonary stent-valve implantation without angiography: role of intravascular ultrasound.

Patients with stenosed biologic pulmonary conduits require redo cardiac surgery to prevent severe right ventricular dysfunction. Following the latest trends, the trans-catheter pulmonary stent-valve implantation represents a new fascinating alternative carrying a lower operative risk, compared with the standard open-heart re-intervention. Traditionally, the pulmonary stent valve is positioned off pump, under fluoroscopic control, and requires angiographies. However, alternative tools not requiring contrast injections for the intra-operative cardiac imaging have to be also considered strongly. The usefulness of intravascular ultrasound for the positioning of aortic endoprosthesis has already been proven in previous reports and, following the same principle, we have started to routinely implant balloon-expandable stent valves (Edwards Sapien? THV) in stenosed pulmonary valve conduits using intravascular ultrasound for the stent-valve positioning without angiography. We describe the intra-operative intravascular imaging technique with technical details.

Controls on ostracod valve geochemistry: Part 2. Carbon and oxygen isotope compositions

The stable carbon and oxygen isotope compositions of fossil ostracods are powerful tools to estimate past environmental and climatic conditions. The basis for such interpretations is that the calcite of the valves reflects the isotopic composition of water and its temperature of formation. However, calcite of ostracods is known not to form in isotopic equilibrium with water and different species may have different offsets from inorganic precipitates of calcite formed under the same conditions. To estimate the fractionation during ostracod valve calcification, the oxygen and carbon isotope compositions of 15 species living in Lake Geneva were related to their autoecology and the environmental parameters measured during their growth. The results indicate that: (1) Oxygen isotope fractionation is similar for all species of Candoninae with an enrichment in 18O of more than 30/00 relative to equilibrium values for inorganic calcite. Oxygen isotope fractionation for Cytheroidea is less discriminative relative to the heavy oxygen, with enrichments in 18O for these species of 1.7 to 2.30/00. Oxygen isotope fractionations for Cyprididae are in-between those of Candoninae and Cytheroidea. The difference in oxygen isotope fractionation between ostracods and inorganic calcite has been interpreted as resulting from a vital effect. (2) Comparison with previous work suggests that oxygen isotope fractionation may depend on the total and relative ion content of water. (3) Carbon isotope compositions of ostracod valves are generally in equilibrium with DIC. The specimens' δ13C values are mainly controlled by seasonal variations in δ13CDIC of bottom water or variation thereof in sediment pore water. (4) Incomplete valve calcification has an effect on carbon and oxygen isotope compositions of ostracod valves. Preferential incorporation of at the beginning of valve calcification may explain this effect. (5) Results presented here as well as results from synthetic carbonate growth indicate that different growth rates or low pH within the calcification site cannot be the cause of oxygen isotope 'vital effects' in ostracods. Two mechanisms that might enrich the 18O of ostracod valves are deprotonation of that may also contribute to valve calcification, and effects comparable to salt effects with high concentrations of Ca and/or Mg within the calcification site that may also cause a higher temperature dependency of oxygen isotope fractionation.

Interplay of mechanotransduction, FOXC2, connexins, and calcineurin signaling in lymphatic valve formation.

The directional flow of lymph is maintained by hundreds of intraluminal lymphatic valves. Lymphatic valves are crucial to prevent lymphedema, accumulation of fluid in the tissues, and to ensure immune surveillance; yet, the mechanisms of valve formation are only beginning to be elucidated. In this chapter, we will discuss the main steps of lymphatic valve morphogenesis, the important role of mechanotransduction in this process, and the genetic program regulated by the transcription factor Foxc2, which is indispensable for all steps of valve development. Failure to form mature collecting lymphatic vessels and valves causes the majority of postsurgical lymphedema, e.g., in breast cancer patients. Therefore, this knowledge will be useful for diagnostics and development of better treatments of secondary lymphedema.

Infection after total ankle replacement : A 5-year retrospective analysis of 92 implanted ankle prostheses (2004-2008).

Objectives: Total ankle replacement (TAR) is increasingly used for treatment of primary or posttraumatic arthritis of the ankle joint, if joint movement is intended to be preserved. Data on characteristics and treatment of ankle prosthetic joint infection (PJI) is limited and no validated therapeutic algorithm exist. Therefore, we analyzed all infections, which occurred in a cohort of implanted ankle prostheses during a 5-year-period.Methods: Between 06/2004 and 12/2008, all patients with an implanted ankle prosthesis at our institution were retrospectively reviewed. All patients were operated by the same surgical team. Ankle PJI was defined as visible purulence, acute inflammation on histopathology, sinus tract, or microbial growth in periprosthetic tissue or sonication fluid of the removed prosthesis. The surgery on the infected ankle prosthesis and the follow-up were performed by the surgical team, who implanted the prosthesis. A specialized septic team consisting of an orthopaedic surgeon and infectious diseases consultant were included in the treatment.Results: During the study period, 92 total ankle prostheses were implanted in 90 patients (mean age 61 years, range 28-80 years). 78 patients had posttraumatic arthritis, 11 rheumatoid arthritis and 3 other degenerative disorder. Ankle PJI occurred in 3 of 92 TAR (3.3%), occurring 1, 2 and 24 months after implantation; the causative organisms were Enterobacter cloacae, Streptococcus pyogenes and Staphylococcus epidermidis, respectively. The ankle prosthesis was removed in all infected patients, including debridement of the surrounding tissue was debrided and insertion of an antibiotic loaded spacer. Provisional arthrodesis was performed by external fixation in two patients and by plaster cast in one. A definitive ankle arthrodesis with a retrograde nail was performed 6 to 8 weeks after prosthesis removal. One patient needed a flap coverage. All 3 patients received intravenous antibiotic treatment for 2 weeks, followed by oral antibiotics for 4-6 weeks. At follow-up visit up to 18 months after start of treatment, all patients were without clinical or laboratory signs of infection.Conclusions: The infection incidence after TAR was 3.3%, which is slightly higher than reported after hip (<1%) or knee arthroplasty (<2%). A two-step approach consisting of removal of the infected prosthesis, combined with local and systemic antibiotic treatment, followed by definitive ankle arthrodesis shows good results. Larger patient cohort and longer follow-up evaluation is needed to define the optimal treatment approach for ankle PJI.

Which available transapical transcatheter valve fits into degenerated aortic bioprostheses?

The transapical transcatheter aortic valve implantation (TA-TAVI) in degenerated aortic bioprosthesis is an emerging therapy for surgically non-amenable patients. However, the presence of different types of aortic bioprostheses (stented and stentless), available in different sizes (19-27 mm), can be at the origin of important mismatches between the malfunctioning, degenerated aortic valves and the inner stent-valves implanted through transapical accesses (23 and 26 mm Edwards Sapien transcatheter stent-valves). We report an emergency TA-TAVI treatment of a severely regurgitant degenerated 23 mm Mitroflow aortic bioprosthesis (Sorin Group, Milano, Italy) implanted seven years earlier in an 80-year-old lady, and we reviewed the current available literature about transapical 'valve-in-valve' procedures to analyze the hemodynamic results and the ideal 'prosthesis-to-prosthesis' match.

Radiographic total disc replacement angle measurement accuracy using the Oxford Cobbometer: precision and bias.

Total disc replacement (TDR) clinical success has been reported to be related to the residual motion of the operated level. Thus, accurate measurement of TDR range of motion (ROM) is of utmost importance. One commonly used tool in measuring ROM is the Oxford Cobbometer. Little is known however on its accuracy (precision and bias) in measuring TDR angles. The aim of this study was to assess the ability of the Cobbometer to accurately measure radiographic TDR angles. An anatomically accurate synthetic L4-L5 motion segment was instrumented with a CHARITE artificial disc. The TDR angle and anatomical position between L4 and L5 was fixed to prohibit motion while the motion segment was radiographically imaged in various degrees of rotation and elevation, representing a sample of possible patient placement positions. An experienced observer made ten readings of the TDR angle using the Cobbometer at each different position. The Cobbometer readings were analyzed to determine measurement accuracy at each position. Furthermore, analysis of variance was used to study rotation and elevation of the motion segment as treatment factors. Cobbometer TDR angle measurements were most accurate (highest precision and lowest bias) at the centered position (95.5%), which placed the TDR directly inline with the x-ray beam source without any rotation. In contrast, the lowest accuracy (75.2%) was observed in the most rotated and off-centered view. A difference as high as 4 degrees between readings at any individual position, and as high as 6 degrees between all the positions was observed. Furthermore, the Cobbometer was unable to detect the expected trend in TDR angle projection with changing position. Although the Cobbometer has been reported to be reliable in different clinical applications, it lacks the needed accuracy to measure TDR angles and ROM. More accurate ROM measurement methods need to be developed to help surgeons and researchers assess radiological success of TDRs.

Transapical aortic valve implantation following a left pneumonectomy.

Transapical transcatheter aortic valve implantation is an emerging technique for high-risk patients with symptomatic aortic valve stenosis, peripheral vascular disease, and severe concomitant comorbidities. However, a previous major surgical intervention involving the left hemithorax and the lung has always been considered a technical surgical challenge or even a potential contraindication for this minimally invasive procedure. With this report, we demonstrate, for the first time, that a previous left pneumonectomy followed by mediastinal radiotherapy does not affect the feasibility of transapical transcatheter aortic valve implantation, and we discuss the preoperative workup and the peculiar intraoperative cardiac imaging and surgical assessment.

Initial and Extended Use of Femoral Versus Nonfemoral Double-Lumen Vascular Catheters and Catheter-Related Infection During Continuous Renal Replacement Therapy.

BACKGROUND: The risk of catheter-related infection or bacteremia, with initial and extended use of femoral versus nonfemoral sites for double-lumen vascular catheters (DLVCs) during continuous renal replacement therapy (CRRT), is unclear. STUDY DESIGN: Retrospective observational cohort study. SETTING & PARTICIPANTS: Critically ill patients on CRRT in a combined intensive care unit of a tertiary institution. FACTOR: Femoral versus nonfemoral venous DLVC placement. OUTCOMES: Catheter-related colonization (CRCOL) and bloodstream infection (CRBSI). MEASUREMENTS: CRCOL/CRBSI rates expressed per 1,000 catheter-days. RESULTS: We studied 458 patients (median age, 65 years; 60% males) and 647 DLVCs. Of 405 single-site only DLVC users, 82% versus 18% received exclusively 419 femoral versus 82 jugular or subclavian DLVCs, respectively. The corresponding DLVC indwelling duration was 6±4 versus 7±5 days (P=0.03). Corresponding CRCOL and CRBSI rates (per 1,000 catheter-days) were 9.7 versus 8.8 events (P=0.8) and 1.2 versus 3.5 events (P=0.3), respectively. Overall, 96 patients with extended CRRT received femoral-site insertion first with subsequent site change, including 53 femoral guidewire exchanges, 53 new femoral venipunctures, and 47 new jugular/subclavian sites. CRCOL and CRBSI rates were similar for all such approaches (P=0.7 and P=0.9, respectively). On multivariate analysis, CRCOL risk was higher in patients older than 65 years and weighing >90kg (ORs of 2.1 and 2.2, respectively; P<0.05). This association between higher weight and greater CRCOL risk was significant for femoral DLVCs, but not for nonfemoral sites. Other covariates, including initial or specific DLVC site, guidewire exchange versus new venipuncture, and primary versus secondary DLVC placement, did not significantly affect CRCOL rates. LIMITATIONS: Nonrandomized retrospective design and single-center evaluation. CONCLUSIONS: CRCOL and CRBSI rates in patients on CRRT are low and not influenced significantly by initial or serial femoral catheterizations with guidewire exchange or new venipuncture. CRCOL risk is higher in older and heavier patients, the latter especially so with femoral sites.

Cardiac rotation and relaxation in patients with aortic valve stenosis.

BACKGROUND: Diastolic dysfunction with delayed relaxation and abnormal passive elastic properties has been described in patients with severe pressure overload hypertrophy. The purpose of this study was to evaluate the time course of rotational motion of the left ventricle in patients with aortic valve stenosis using myocardial tagging. METHODS: Myocardial tagging is a non-invasive method based on magnetic resonance which makes it possible to label ('tag') specific myocardial regions. From the motion of the tag's cardiac rotation, radial displacement and translational motion can be determined. In 12 controls and 13 patients with severe aortic valve stenosis systolic and diastolic wall motion was assessed in an apical and basal short axis plane. RESULTS: The normal left ventricle performs a systolic wringing motion around the ventricular long axis with clockwise rotation at the base (-4.4+/-1.6 degrees) and counter-clockwise rotation at the apex (+6.8+/-2.5 degrees) when viewed from the apex. During early diastole an untwisting motion can be observed which precedes diastolic filling. In patients with aortic valve stenosis systolic rotation is reduced at the base (-2.4+/-2.0 degrees; P<0.01) but increased at the apex (+12.0+/-6.0 degrees; P<0.05). Diastolic untwisting is delayed and prolonged with a decrease in normalized rotation velocity (-6.9+/-1.1 s(-1)) when compared to controls (-10.7+/-2.2 s(-1); P<0.001). Maximal systolic torsion is 8.0+/-2.1 degrees in controls and 14.1+/-6.4 degrees (P<0.01) in patients with aortic valve stenosis. CONCLUSIONS: Left ventricular pressure overload hypertrophy is associated with a reduction in basal and an increase in apical rotation resulting in increased torsion of the ventricle. Diastolic untwisting is delayed and prolonged. This may explain the occurrence of diastolic dysfunction in patients with severe pressure overload hypertrophy.

Quelles applications raisonnables pour l'anticoagulation régionale au citrate en épuration extrarénale [What reasonable applications for regional citrate anticoagulation in renal replacement therapy?].

Regional citrate anticoagulation of the extracorporeal circuits (CRA) experienced considerable growth over the past decade. This development is partly explained by the significant progresses made in the field of bioengineering. These allow a secure administration of citrate, while an increasing availability of ionized calcium measurement at the bedside allows reactivity in monitoring the treatment. An increasing severity of the medical condition of patients requiring blood purification treatment gives more contrast to the profile of patient who may benefit from a CRA. If some methods of renal replacement therapy are well suited to this mode of anticoagulation, others are, to date, only at the stage of development and are applied under close medical supervision.

A new self-expanding aortic stent valve with annular fixation: in vitro haemodynamic assessment.

OBJECTIVE: Balloon-expandable stent valves require flow reduction during implantation (rapid pacing). The present study was designed to compare a self-expanding stent valve with annular fixation versus a balloon-expandable stent valve. METHODS: Implantation of a new self-expanding stent valve with annular fixation (Symetis, Lausanne, Switzerland) was assessed versus balloon-expandable stent valve, in a modified Dynatek Dalta pulse duplicator (sealed port access to the ventricle for transapical route simulation), interfaced with a computer for digital readout, carrying a 25 mm porcine aortic valve. The cardiovascular simulator was programmed to mimic an elderly woman with aortic stenosis: 120/85 mmHg aortic pressure, 60 strokes/min (66.5 ml), 35% systole (2.8 l/min). RESULTS: A total of 450 cardiac cycles was analysed. Stepwise expansion of the self-expanding stent valve with annular fixation (balloon-expandable stent valve) resulted in systolic ventricular increase from 120 to 121 mmHg (126 to 830+/-76 mmHg)*, and left ventricular outflow obstruction with mean transvalvular gradient of 11+/-1.5 mmHg (366+/-202 mmHg)*, systolic aortic pressure dropped distal to the valve from 121 to 64.5+/-2 mmHg (123 to 55+/-30 mmHg) N.S., and output collapsed to 1.9+/-0.06 l/min (0.71+/-0.37 l/min* (before complete obstruction)). No valve migration occurred in either group. (*=p<0.05). CONCLUSIONS: Implantation of this new self-expanding stent valve with annular fixation has little impact on haemodynamics and has the potential for working heart implantation in vivo. Flow reduction (rapid pacing) is not necessary.

Short-term clinical outcomes among patients undergoing transcatheter aortic valve implantation in Switzerland: the Swiss TAVI registry.

AIMS: To evaluate short-term clinical outcomes following transcatheter aortic valve implantation (TAVI) using CE-mark approved devices in Switzerland. METHODS AND RESULTS: The Swiss TAVI registry is a national, prospective, multicentre, monitored cohort study evaluating clinical outcomes in consecutive patients undergoing TAVI at cardiovascular centres in Switzerland. From February 2011 to March 2013, a total of 697 patients underwent TAVI for native aortic valve stenosis (98.1%), degenerative aortic bioprosthesis (1.6%) or severe aortic regurgitation (0.3%). Patients were elderly (82.4±6 years), 52% were females, and the majority highly symptomatic (73.1% NYHA III/IV). Patients with severe aortic stenosis (mean gradient 44.8±17 mmHg, aortic valve area 0.7±0.3 cm²) were either deemed inoperable or at high risk for conventional surgery (STS 8.2%±7). The transfemoral access was the most frequently used (79.1%), followed by transapical (18.1%), direct aortic (1.7%) and subclavian access (1.1%). At 30 days, rates of all-cause mortality, cerebrovascular events and myocardial infarction were 4.8%, 3.3% and 0.4%, respectively. The most frequently observed adverse events were access-related complications (11.8%), permanent pacemaker implantation (20.5%) and bleeding complications (16.6%). The Swiss TAVI registry is registered at ClinicalTrials.gov (NCT01368250). CONCLUSIONS: The Swiss TAVI registry is a national cohort study evaluating consecutive TAVI procedures in Switzerland. This first outcome report provides favourable short-term clinical outcomes in unselected TAVI patients.