Long-term radiation exposure in patients undergoing EVAR: Reflecting clinical day-to-day practice to assess realistic radiation burden.

Endovascular repair of aortic aneurysms (EVAR) has become an established treatment option currently applied in an increasing numbers of patients with aortic aneurysms. Advantages include reduced surgical trauma, procedural time, intensive care unit and hospital lengths of stay, blood loss as well as morbidity and mortality.The optimal imaging modalities in EVAR follow-up as well as the appropriate intervals between these follow-ups remain subject of controversial discussion. Objective of this study was the evaluation of the realistic radiation exposure and risk estimate postop EVAR treatment.Of the follow-ups required according to the surveillance schedule during the first year post-EVAR, only 68.3% were actually implemented. Of those required from the second year onwards, an average of 70% was actually performed. During the observation period, each patient underwent a mean of 4.3 CTAs. The median ED calculated from all CTAs was 24. 5 mSv. The minimum and maximum cumulative EDs for the entire observation period were 55 mSv and 310 mSv, respectively.

Identification of Factors Influencing Cumulative Long-Term Radiation Exposure in Patients Undergoing EVAR.

Patients who undergo endovascular repair of aortic aneurysms (EVAR) require life-long surveillance because complications including, in particular, endoleaks, aneurysm rupture, and graft dislocation are diagnosed in a certain share of the patient population and may occur at any time after the original procedure. Radiation exposure in patients undergoing EVAR and post-EVAR surveillance has been investigated by previous authors. Arriving at realistic exposure data is essential because radiation doses resulting from CT were shown to be not irrelevant. Efforts directed at identification of factors impacting the level of radiation exposure in both the course of the EVAR procedure and post-EVAR endovascular interventions and CTAs are warranted as potentially modifiable factors may offer opportunities to reduce the radiation. In the light of the risks found to be associated with radiation exposure and considering the findings above, those involved in EVAR and post-EVAR surveillance should aim at optimal dose management.

Allogeneic Blood Product Usage in Coronary Artery Bypass Grafting (CABG) with minimalized Extracorporeal Circulation System (MECC) Versus Standard On-Pump Coronary Artery Bypass Grafting.

AIM: Intraoperative allogeneic blood product transfusion (ABPT) in cardiac surgery is associated with worse overall outcome, including mortality. The objective of this study was to evaluate the ABPTs in minimalized extracorporeal cardiopulmonary (MECC(TM)) compared with standard open system on-pump coronary revascularization. METHODS: Data of 156 patients undergoing myocardial revascularization between September 2008 and September 2010 were reviewed. 83 patients were operated by the MECC technique and 73 were treated by standard extracorporeal circulation (sECC). ABPT and overall early postoperative complications were analyzed. RESULTS: Operative mortality and morbidity were similar in both groups. ABPT in the MECC group was significantly lower than in the sECC group both intraoperatively (7.2 vs. 60.3% of patients p<0.001) and during the first five postoperative days (19.3 vs. 57.5%; p<0.001). "Skin to skin"- (214 ± 45 vs. 232 ± 45 min; p=0.012), cardiopulmonary bypass (CPB) - (82 ± 25 vs. 95 ± 26 min; p=0.014), and X-clamp- times (50 ± 16 vs. 56 ± 17 min; p=0.024) were significantly lower in the MECC group than in the sECC group. Length of ICU (intensive care unit) - and hospital stay were also significantly lower in the MECC group vs. the sECC group (26.7 ± 20.2 vs. 54.5 ± 68.9 h; p<0.001, and 12.0 ± 4.1 vs. 14.5 ± 4.6 days; p<0.001). CONCLUSION: Application of MECC as on-pump coronary artery bypass graft (CABG) results in significantly lower ABPT as well as shorter ICU and in-hospital stay. In order to achieve these benefits of MECC autologous retrograde priming, Bispectral index (BIS) monitoring, intraoperative cell salvage, meticulous hemostasis and strict peri- and postoperative volume management are crucial.

Daptomycin for the treatment of major gram-positive infections after cardiac surgery.

BACKGROUND: Infection is a main cause of morbidity and mortality after heart surgery, with multi-resistant pathogens increasingly representing a challenge. Daptomycin provides bactericidal activity against gram-positive organisms that are resistant to standard treatment including vancomycin. METHODS: A cohort of cardiac surgical patients, treated with daptomycin for major infection at two tertiary care centers, were retrospectively studied with a particular focus on the type of infection, causative pathogens and co-infections, daptomycin dosage, adverse events and outcome in order to provide evidence for the efficiency and safety of daptomycin in a distinct high-risk patient population. RESULTS: Sixty-five patients (87.7 % males, 60.4 ± 13.5 years) who had undergone aortic surgery (20.0 %), ventricular assist device (VAD) implantation (21.5 %), combined procedures (21.5 %), coronary artery bypass grafting (12.3 %), isolated valve surgery (15.4 %) and heart transplantation (7.7 %) were diagnosed with catheter-related infection (26.1 %), valve endocarditis (18.8 %), sternal wound (13.0 %), VAD-associated (11.6 %), cardiac implantable electrophysiological device (CIED)-associated (4.1 %), respiratory tract (4.3 %), bloodstream (4.3 %) and other infection (4.3 %). In 13.0 %, no focus of infection was identified though symptoms of severe infection were present. The most frequent pathogens were Staphylococcus epidermidis (30.4 %), Staphylococcus aureus (23.1 %) and Enterococcus species (10.1 %). Daptomycin doses ranging from 3 mg/kg every 48 h to 10 mg/kg every 24 h were administered for 15.4 ± 11.8 days. 87.0 % of the cases were classified as success, 7.2 % as treatment failure and 5.8 as non-evaluable. Adverse events were limited to one case of mild and one case of moderate neutropenia with recovery upon termination of treatment. CONCLUSION: Daptomycin proved safe and effective in major infection in high-risk cardiac surgical patients.

Left ventricular non-compaction cardiomyopathy and left ventricular assist device: a word of caution.

BACKGROUND: In patients with left ventricular non-compaction (LVNC), implantation of a left ventricular assist device (LVAD) may be performed as a bridge to transplantation. In this respect, the particular characteristics of the left ventricular myocardium may represent a challenge. CASE PRESENTATION: We report a patient with LVNC who required urgent heart transplantation for inflow cannula obstruction nine months after receiving a LVAD. LVAD parameters, echocardiography and examination of the explanted heart suggested changes of left ventricular configuration brought about by LVAD support as the most likely cause of inflow cannula obstruction. CONCLUSIONS: We conclude that changes experienced by non-compacted myocardium during LVAD support may give rise to inflow cannula obstruction and flow reduction. Presence of LVNC mandates tight surveillance for changes in LV configuration and LVAD flow characteristics and may justify urgent transplantation listing status.

Computational evaluation of aortic occlusion and the proposal of a novel, improved occluder: Constrained endo-aortic balloon occlusion.

Because aortic occlusion is arguably one of the most dangerous aortic manipulation maneuvers during cardiac surgery in terms of perioperative ischemic neurological injury, the purpose of this investigation is to assess the structural mechanical impact resulting from the use of existing and newly proposed occluders. Existing (clinically used) occluders considered include different cross-clamps (CCs) and endo-aortic balloon occlusion (EABO). A novel occluder is also introduced, namely, constrained EABO (CEABO), which consists of applying a constrainer externally around the aorta when performing EABO. Computational solid mechanics are employed to investigate each occluder according to a comprehensive list of functional requirements. The potential of a state of occlusion is also considered for the first time. Three different constrainer designs are evaluated for CEABO. Although the CCs were responsible for the highest strains, largest deformation, and most inefficient increase of the occlusion potential, it remains the most stable, simplest, and cheapest occluder. The different CC hinge geometries resulted in poorer performance of CC used for minimally invasive procedures than conventional ones. CEABO with a profiled constrainer successfully addresses the EABO shortcomings of safety, stability, and positioning accuracy, while maintaining its complexities of operation (disadvantage) and yielding additional functionalities (advantage). Moreover, CEABO is able to achieve the previously unattainable potential to provide a clinically determinable state of occlusion. CEABO offers an attractive alternative to the shortcomings of existing occluders, with its design rooted in achieving the highest patient safety. Copyright © 2016 John Wiley & Sons, Ltd.

Suspected involvement of EPTFE membrane in sterile intrathoracic abscess and pericardial empyema in a multi-allergic LVAD recipient: a case report.

Device-related infections in recipients of left ventricular assist devices (LVAD) have been recognized as a major source of morbidity and mortality. They require a high level of diagnostic effort as part of the overall burden resulting from infectious complications in LVAD recipients. We present a multi-allergic patient who was treated for persistent sterile intrathoracic abscess formation and pericardial empyema following minimally invasive LVAD implantation including use of a sheet of e-polytetrafluoroethylene (ePTFE) membrane to restore pericardial integrity. Sterile abscess formation and pericardial empyema recurred after surgical removal until the ePTFE membrane was removed, suggesting that in disposed patients, ePTFE may be related to sterile abscess formation or sterile empyema.

Coronary sinus lead extraction in CRT patients with CIED-related infection: risks, implications and outcomes.

AIM: The aim of the study was to examine risks, implications and outcomes of coronary sinus (CS) lead extraction in patients with infections of cardiac resynchronization therapy (CRT) systems. METHODS: The study included 40 (65.5 ± 11.1 years; 80% male) transvenous CS lead extraction procedures performed between 2000-2011. Nine (22.5%) patients suffered from infection and included one sepsis (11.1%), two (22.2%) of lead and valve endocarditis, and four (44.4%) cases of pocket infection. CS lead extraction in the infection subgroup was performed between 14 days and more than five years after the last CIED-related surgical procedure. RESULTS: Totally 42 CS and 35 non-CS leads were extracted. Leads extracted in the infection subgroup were significantly longer in situ (49.7 ± 30.7 months) compared to the non-infection subgroup (19.2 ± 28.6 months). Extraction in infected patients required more aggressive methods and longer exposure to radiation than non-infected. Procedural success without major complications was achieved in all patients. Minor post-procedural complications occurred in four (44.4%) of the infected and one (3.2%) of the non-infected patients and were surgical-related in three cases. Overall hospitalization times were significantly longer for the infection than for the non-infection subgroup (21.4 ± 15 versus 9.6 ± 6.9 days). CONCLUSION: Our results support the concept of complete CIED-system removal in CIED-associated infection, regardless of whether or not infection appears to be limited to the generator pocket site, despite risk of heart failure, patient frailty and a high level of comorbidity. An interdisciplinary approach encompassing appropriate diagnostic, procedural and safety standards allows CS lead extraction in this high-risk subpopulation to be performed with excellent outcomes and low complication rates.

Dose/time-dependent modulation of the endothelial function through induction agents: non-depleting versus depleting agents.

BACKGROUND: Polyclonal anti-thymocyte globulins (ATGs) and anti-CD25 antibodies are agents used for induction of immunosuppression in solid-organ transplantation. We aimed to investigate the effect of different regimens of these immunosuppressive induction agents on transendothelial migration of peripheral blood mononuclear cells (PBMC) and evaluated the endothelial apoptosis after treatment. METHODS: Human microvascular endothelial cells were either activated with tumor necrosis factor-α/interferon-γ or not and further treated with 25 or 125 µg/mL ATG (Thymoglobulin, Sanofi-Aventis, Germany) for 2 hours or 24 hours, or with 5 µg/mL Basiliximab (Simulect, Novartis, Germany) for 2 hours or 24 hours. PBMC were either activated with phytohaemagglutinin (PHA) or not and further treated with 25 or 125 µg/mL ATG or with 5 µg/mL Basiliximab for 2 h and then used for transendothelial migration assays. Apoptosis of endothelial cells was detected by means of Annexin-V staining after 2-hour incubation with either 25 or 125 µg/mL ATG or 5 µg/mL Basiliximab. RESULTS: Prophylactic 24-hour administration of ATG to naive endothelial cells without PBMC treatment reduced transendothelial migration. Prophylactic 24-hour administration of ATG and Basiliximab to naive endothelial cells after PBMC treatment with the same agents reduced the transendothelial migration after 24 hours. In both cases, no effect could be observed after 2-hour treatment. Basiliximab but not ATG showed a reduction of transmigration after 2-hour treatment of PBMCs without naive EC treatment. Apoptosis of endothelial cells after treatment increased in both cases, being in case of ATG dose-dependent, increasing from 1.2% after either 25 µg/mL ATG to 8.7% after 125 µg/mL ATG. CONCLUSIONS: Immunosuppressive induction agents modulate the endothelial activity in a dose- and time-dependent manner. Our results suggest that administration of induction agents over longer time periods could provide a potential benefit regarding endothelial immunomodulation. Increased doses may, however, show a deleterious effect on endothelial survival.

The secretion pattern of perivascular fat cells is different from that of subcutaneous and visceral fat cells.

AIMS/HYPOTHESIS: We have previously found that the mass of perivascular adipose tissue (PVAT) correlates negatively with insulin sensitivity and post-ischaemic increase in blood flow. To understand how PVAT communicates with vascular vessels, interactions between perivascular, subcutaneous and visceral fat cells with endothelial cells (ECs) were examined with regard to inflammatory, metabolic and angiogenic proteins. To test for possible in vivo relevance of these findings, circulating levels of the predominant secretion product, hepatocyte growth factor (HGF), was measured in individuals carefully phenotyped for fat distribution patterns. METHODS: Mono- and co-cultures of human primary fat cells with ECs were performed. mRNA expression and protein production were studied using Luminex, cytokine array, RealTime Ready and ELISA systems. Effects of HGF on vascular cells were determined by WST assays. In patients, HGF levels were measured by ELISA, and the mass of different fat compartments was determined by whole-body MRI. RESULTS: In contrast with other fat cell types, PVAT cells released higher amounts of angiogenic factors, e.g. HGF, acidic fibroblast growth factor, thrombospondin-1, serpin-E1, monocyte chemotactic protein-1 and insulin-like growth factor-binding protein -3. Cocultures showed different expression profiles from monocultures, and mature adipocytes differed from pre-adipocytes. HGF was preferentially released by PVAT cells and stimulated EC growth and smooth muscle cell cytokine release. Finally, in 95 patients, only PVAT, not visceral or subcutaneous mass, correlated independently with serum HGF levels (p = 0.03; r = 0.225). CONCLUSIONS: Perivascular (pre-)adipocytes differ substantially from other fat cells with regard to mRNA expression and protein production of angiogenic factors. This may contribute to fat tissue growth and atherosclerotic plaque complications. Higher levels of angiogenic factors, such as HGF, in patients with increased perivascular fat mass may have pathological relevance.

Prevention of device-related tissue damage during percutaneous deployment of tissue-engineered heart valves.

BACKGROUND: Endovascular application of pulmonary heart valves has been recently introduced clinically. A tissue-engineering approach was pursued to overcome the current limitations of bovine jugular vein valves (degeneration and limited longevity). However, deployment of the delicate tissue-engineered valves resulted in severe tissue damage. Therefore the objective of this study was to prevent tissue damage during the folding and deployment maneuver. MATERIAL AND METHODS: Porcine pulmonary heart valves, small intestinal submucosa, and ovine carotid arteries were obtained from a slaughterhouse. After dissection and antimicrobial incubation, the valves were trimmed (removal of sinus and most of the muscular ring) to fit into the deployment catheter. The inside (in-stent group, n = 6) or outside (out-stent group, n = 6) of a nitinol stent was covered by an acellular small intestinal submucosa, and the valves were sutured into the stent. The valves were folded, tested for placement in the deployment catheter, and decellularized enzymatically. Myofibroblasts were obtained from carotid artery segments and seeded onto the scaffolds. The seeded constructs were placed in a dynamic bioreactor system and cultured for 16 consecutive days. After endothelial cell seeding, the constructs were folded, deployed, and processed for histology and surface electron microscopy. RESULTS: The valves opened and closed competently throughout the entire dynamic culture. Surface electron microscopy revealed an almost completely preserved tissue in the in-stent group. Stents covered with small intestinal submucosa on the outside, however, showed severe damage. CONCLUSION: This study demonstrates that small intestinal submucosa covering of the inside of a pulmonary valved stent can prevent stent strut-related tissue damage.

Deairing of the venous drainage in standard extracorporeal circulation results in a profound reduction of arterial micro bubbles.

OBJECTIVE: Standard extracorporeal circulation (ECC) remains the staple procedure for cardiac surgeons. Despite modern membrane oxygenators and arterial filters micro bubbles are regularly detected in the arterial line. We investigated whether initial deairing of the venous drainage during connection can reduce the quantity and size of micro bubbles on the arterial side. METHODS: 12 patients underwent isolated coronary artery revascularization with conventional ECC using a two-stage venous catheter and an open, passive venous return into a reservoir. In 6 patients (Control) the venous catheter was routinely connected to the venous line, thereby accepting moderate incorporation of air. In another 6 patients (deaired) the catheter was connected avoiding any visible air entrapment. A bubble counter was used to detect the number and size of any micro bubbles in the arterial line of the ECC. The total number of bubbles as well as the number of bubbles of different sizes was assessed directly after initiation of ECC and during the first 60 sec. RESULTS: All patients had an uneventful surgery with a normal postoperative course. In the Control group a considerable number of bubbles of all sizes occurred initially and after 60 sec. In contrast, very few bubbles were detected in the deaired group. CONCLUSION: Incorporated venous air inevitably reaches the arterial side of the ECC. As deairing of the venous line is a simple and effective manoeuvre to significantly reduce the amount of micro bubbles on the arterial side, we recommend and perform routine deairing in all our patients.

Successful in situ repair of a symptomatic left main coronary artery aneurysm by a saphenous vein graft.

In a male patient, presenting with progressive angina refractory to medical treatment, a solitary aneurysm of the left main coronary artery without fistula, a 2 cm large atrial septal defect (ASD) and a persisting left superior caval vein were diagnosed. Successful resection with subsequent in situ repair by vein grafting of the left anterior descending artery and the circumflex coronary artery system and direct closure of the ASD are described.

Efficient and stable retroviral transfection of ovine endothelial cells with green fluorescent protein for cardiovascular tissue engineering.

To determine whether cellular components of tissue-engineered cardiovascular structures are derived from cells harvested and seeded onto an acellular scaffold, or from cells originating from surrounding tissue (e.g., proximal and distal anastomosis), cellular retroviral transfection with green fluorescent protein (GFP) was used. Ovine endothelial cells (ECs) were transfected with a Moloney murine leukemia virus (Mo-MuLV)-based retroviral vector expressing GFP. Transfection was evaluated by fluorescence microscopy and fluorescence-activated cell sorting. The rate of transfection of the primary cells was 33.4% for ECs, 48 hours after transfection. Stable transfection could be observed for at least 25 subsequent passages. Retroviral transfection with GFP enables stable and reliable long-term labeling of ovine ECs. This approach might offer an attractive pathway to study tissue development, with emphasis on distinguishing between cellular components initially seeded onto a construct and those occurring as a result of cell ingrowth from surrounding tissue.

Prediction of safe duration of hypothermic circulatory arrest by near-infrared spectroscopy.

OBJECTIVE: Hypothermic circulatory arrest is widely used for adults with aortic arch disease as well as for children with congenital heart disease. At present, no method exists for monitoring safe duration of circulatory arrest. Near-infrared spectroscopy is a new technique for noninvasive monitoring of cerebral oxygenation and energy state. In the current study, the relationship between near-infrared spectroscopy data and neurologic outcome was evaluated in a survival piglet model with hypothermic circulatory arrest. METHODS: Thirty-six piglets (9.36 +/- 0.16 kg) underwent circulatory arrest under varying conditions with continuous monitoring by near-infrared spectroscopy (temperature 15 degrees C or 25 degrees C, hematocrit value 20% or 30%, circulatory arrest time 60, 80, or 100 minutes). Each setting included 3 animals. Neurologic recovery was evaluated daily by neurologic deficit score and overall performance category. Brain was fixed in situ on postoperative day 4 and examined by histologic score. RESULTS: Oxygenated hemoglobin signal declined to a plateau (nadir) during circulatory arrest. Time to nadir was significantly shorter with lower hematocrit value (P <.001) and higher temperature (P <.01). Duration from reaching nadir until reperfusion ("oxygenated hemoglobin signal nadir time") was significantly related to histologic score (r (s) = 0.826), neurologic deficit score (r (s) = 0.717 on postoperative day 1; 0.716 on postoperative day 4), and overall performance category (r (s) = 0.642 on postoperative day 1; 0.702 on postoperative day 4) (P <.001). All animals in which oxygenated hemoglobin signal nadir time was less than 25 minutes were free of behavioral or histologic evidence of brain injury. CONCLUSION: Oxygenated hemoglobin signal nadir time determined by near-infrared spectroscopy monitoring is a useful predictor of safe duration of circulatory arrest. Safe duration of hypothermic circulatory arrest is strongly influenced by perfusate hematocrit value and temperature during circulatory arrest.

Patch augmentation of the pulmonary artery with bioabsorbable polymers and autologous cell seeding.

OBJECTIVE: In recent years bioabsorbable synthetic or biologic materials have been used to augment the pulmonary artery or the right ventricular outflow tract. However, each of these polymers has one or more shortcomings. None of these patch materials has been seeded with cells. Thus, we have tested a fast-absorbing biopolymer, poly-4-hydroxybutyric acid, with autologous cell seeding for patch augmentation of the pulmonary artery in a juvenile sheep model. METHODS: Vascular cells were isolated from ovine peripheral veins (n = 6). Bioabsorbable porous poly-4-hydroxybutyric acid patches (porosity > 95%) were seeded on 3 consecutive days with a mixed vascular cell suspension (21.3 +/- 1.3 x 10(6) cells). Forty-five (+/- 2) days after the vessel harvest, 1 unseeded and 6 autologously seeded control patches were implanted into the proximal pulmonary artery. The animals received no postoperative anticoagulation. Follow-up was performed with echocardiography after 1 week and before explantation after 1, 7, and 24 weeks (2 animals each) for the seeded control patches and after 20 weeks for the nonseeded control patch. RESULTS: All animals survived the procedure. Postoperative echocardiography of the seeded patches demonstrated a smooth surface without dilatation or stenosis. Macroscopic appearance showed a smooth internal surface with increasing tissue formation. Histology at 169 days demonstrated a near-complete resorption of the polymer and formation of organized and functional tissue. Biochemical assays revealed increasing cellular and extracellular matrix contents. The control patch showed a slight bulging, indicating a beginning dilatation. CONCLUSION: This experiment showed that poly-4-hydroxybutyric acid is a feasible patch material in the pulmonary circulation.

Tissue-engineered valved conduits in the pulmonary circulation.

OBJECTIVE: Bioprosthetic and mechanical valves and valved conduits are unable to grow, repair, or remodel. In an attempt to overcome these shortcomings, we have evaluated the feasibility of creating 3-leaflet, valved, pulmonary conduits from autologous ovine vascular cells and biodegradable polymers with tissue-engineering techniques. METHODS: Endothelial cells and vascular medial cells were harvested from ovine carotid arteries. Composite scaffolds of polyglycolic acid and polyhydroxyoctanoates were formed into a conduit, and 3 leaflets (polyhydroxyoctanoates) were sewn into the conduit. These constructs were seeded with autologous medial cells on 4 consecutive days and coated once with autologous endothelial cells. Thirty-one days (+/-3 days) after cell harvesting, 8 seeded and 1 unseeded control constructs were implanted to replace the pulmonary valve and main pulmonary artery on cardiopulmonary bypass. No postoperative anticoagulation was given. Valve function was assessed by means of echocardiography. The constructs were explanted after 1, 2, 4, 6, 8, 12, 16, and 24 weeks and evaluated macroscopically, histologically, and biochemically. RESULTS: Postoperative echocardiography of the seeded constructs demonstrated no thrombus formation with mild, nonprogressive, valvular regurgitation up to 24 weeks after implantation. Histologic examination showed organized and viable tissue without thrombus. Biochemical assays revealed increasing cellular and extracellular matrix contents. The unseeded construct developed thrombus formation on all 3 leaflets after 4 weeks. CONCLUSION: This experimental study showed that valved conduits constructed from autologous cells and biodegradable matrix can function in the pulmonary circulation. The progressive cellular and extracellular matrix formation indicates that the remodeling of the tissue-engineered structure continues for at least 6 months.