Incomplete Expansion Research Articles

The mechanisms of late scaffold thrombosis.

Coronary scaffolds have been recently developed to address the long-term limitations of metallic drug eluting stents. Concerns have however been expressed on the safety of these devices, with evidence of both early and late scaffold thrombosis. While early thrombosis has been associated with incomplete scaffold expansion, leading to flow disturbances, blood recirculation, and platelet activation, the pathophysiology of late events remains less understood. Recent cases series have shown that malapposition and scaffold dismantling might play a role in this phenomenon, an observation that further confirms the importance of an accurate implantation. Further, the role of dual antiplatelet therapy, and whether prolonging it may reduce event rates, remains to be elucidated. As well, the role of inflammatory phenomena has been proposed but never demonstrated. This brief review summarizes the current evidence on these phenomena.

Connecting the Failure of K Theory inside and above Vegetation Canopies and Ejection–Sweep Cycles by a Large-Eddy Simulation

AbstractParameterizations of biosphere–atmosphere interaction processes in climate models and other hydrological applications require characterization of turbulent transport of momentum and scalars between vegetation canopies and the atmosphere, which is often modeled using a turbulent analogy to molecular diffusion processes. Simple flux–gradient approaches (K theory) fail for canopy turbulence, however. One cause is turbulent transport by large coherent eddies at the canopy scale, which can be linked to sweep–ejection events and bear signatures of nonlocal organized eddy motions. The K theory, which parameterizes the turbulent flux or stress proportional to the local concentration or velocity gradient, fails to account for these nonlocal organized motions. The connection to sweep–ejection cycles and the local turbulent flux can be traced back to the turbulence triple moment . In this work, large-eddy simulation is used to investigate the diagnostic connection between the failure of K theory and sweep–ejection motions. Analyzed schemes are quadrant analysis and complete and incomplete cumulant expansion methods. The latter approaches introduce a turbulence time scale in the modeling. Furthermore, it is found that the momentum flux and sensible heat flux need different formulations for the turbulence time scale. Accounting for buoyancy in stratified conditions is also deemed important in addition to accounting for nonlocal events to predict the correct momentum or scalar fluxes.

Prospective rAndomized, single-blind, mulTicenter study of sirolimus-eluting coRonary stent “Calypso” vs everolimus-eluting cOronary stenT “XiencePrime”: results of the PATRIOT trial

Aim. This trial was aimed at comparing the efficacy and safety of sirolimus-eluting coronary stent “Calypso” (Angioline) and everolimus-eluting coronary stent “XiencePrime” (Abbott Vascular) when used for treatment of ischemic heart disease patients.Methods. The trial included patients suitable for coronary revascularization with coronary stenting. They underwent a standard revascularization procedure and were randomized in 2:1 ratio to receive “Calypso” coronary stent (Angioline) (n = 407) or “XiencePrime” coronary stent (AbbottVascular) (n = 203). The follow-up period was 12 months. In order to detect restenosis (secondary endpoint), angiographic follow-up was performed in 20% of cases at 12 months. The trial protocol had no limitations regarding the length of lesions, number of target lesions and number of implanted stents. The main exclusion criterion was STEMI. The composite primary endpoint included one-year target lesion-related complications determined as cardiogenic death, target vessel myocardial infarction, clinically indicated target lesion revascularization. The primary endpoint data were evaluated by an independent committee.Results. In the trial, 55% of patients had acute coronary syndrome with ST elevation and type C lesions were detected in 46% of cases. In “Calypso” and “XiencePrime” groups, TLF occurred in 5.4% and 6.4% respectively (absolute risk difference in TLF accounted for 1%, 95% CI [---;2.1%]; p non-inferiority = 0.017). Thus, the hypothesis of non-inferiority of “Calypso” as compared to “XiencePrime” was confirmed. The incidence of stent thrombosis (definite and probable) was relatively low and had no significant differences between “Calypso” and “XiencePrime” groups (0.73% and 0%; p>0.05). Definite stent thrombosis was noted in two cases in the “Calypso” group (0.49%), in one case the cause of thrombosis turned out to be incomplete stent expansion after implantation.Conclusion. “Calypso” sirolimus eluting stent was not inferior to “XiencePrime” everolimus-eluting stent in treating patients with coronary heart disease.Received 7 November 2017. Revised 13 November 2017. Accepted 20 November 2017.Funding: The study was funded by “Angioline Interventional Devices” (Novosibirsk, Russian Federation). The supporting source had no involvement in study design; collection, analysis and interpretation of data; writing of the report; and in the decision to submit the article for publication.Conflict of interest: The authors declare no conflict of interest.

Thrombose de valve post-TAVI

GoalsTranscatheter aortic valve or leaflets thrombosis are mainly misapprehended. It negatively impacts the long-term efficiency of such prosthesis. Moreover, its incidence is presumably higher than previously described. EpidemiologyRecently reported subclinical leaflet thrombosis, occurring between first to third months after implantation, is about 10to 15%. All prosthesis are concerned by potential thrombosis. DiagnosisTranscatheter aortic valve thrombosis is usually detected on the basis of increased transvalvular pressure gradients or symptoms at routine follow-up. Main causes of post-TAVI thrombosis are: elderly patients, incomplete TAVI expansion, incomplete TAVI apposition to the aortic wall, areas of diminished blood flow and stagnation around the prosthesis. Main risk-factors of thrombosis are: large valves, patients with ejection fraction lower than 35%, valve-in-valve implantation, males, patients with large sinus of Valsalva, patients without anticoagulants. TreatmentPost-TAVI anti thrombotic regimen remains empirical. It is based on aspirin alone or dual antiplatelet therapy for 1–6months, followed by aspirin for life. Symptomatic patients with thrombus-based valve dysfunction are to be treated by oral anticoagulation (i.e., VKA or new oral anticoagulants NOAC). This treatment allows the restoration of normal leaflet motion in patients with a median time of 14 days.

Effectiveness of Ambulatory Tru-Close Thoracic Vent for the Outpatient Management of Pneumothorax: A Prospective Pilot Study.

ObjectiveThis study aimed to assess the technical feasibility, procedural safety, and long-term therapeutic efficacy of a small-sized ambulatory thoracic vent (TV) device for the treatment of pneumothorax.Materials and MethodsFrom November 2012 to July 2013, 18 consecutive patients (3 females, 15 males) aged 16–64 years (mean: 34.7 ± 14.9 years, median: 29 years) were enrolled prospectively. Of these, 15 patients had spontaneous pneumothorax and 3 had iatrogenic pneumothorax. A Tru-Close TV with a small-bore (11- or 13-Fr) catheter was inserted under bi-plane fluoroscopic assistance.ResultsTechnical success was achieved in all patients. Complete lung re-expansion was achieved at 24 hours in 88.9% of patients (16/18 patients). All patients tolerated the procedure and no major complications occurred. The patients' mean numeric pain intensity score was 2.4 (range: 0–5) in daily life activity during the TV treatment. All patients with spontaneous pneumothorax underwent outpatient follow-up. The mean time to TV removal was 4.7 (3–13) days. Early surgical conversion rate of 16.7% (3/18 patients) occurred in 2 patients with incomplete lung expansion and 1 patient with immediate pneumothorax recurrence post-TV removal; and late surgical conversion occurred in 2 of 18 patients (11.1%). The recurrence-free long-term success rate was 72.2% (13/18 patients) during a 3-year follow-up period from November 2012 to June 2016.ConclusionTV application was a simple, safe, and technically feasible procedure in an outpatient clinic, with an acceptable long-term recurrence-free rate. Thus, TV could be useful for the immediate treatment of pneumothorax.

P3.04-045 Primary Lung Cancer Presenting as Pneumothorax: Topic: Miscellaneous II

Analysis of our patients with primary lung cancer presenting as pneumothorax. Between 2010 -2015 we treated in our clinic among 338 adults (258 men and 80 women) presenting with spontaneous pneumothorax, there were nine men and two woman with lung cancer: Seven squamous cell carcinoma, three adenocarcinoma and one oat cell carcinoma. Pneumothorax led to the diagnosis in 11 cases and the remaining occurred as a complication of known neoplastic disease. The average age was 60 years from (32-72 years old). We analyze these 11 cases treated in our hospital. In patients with normal chest x-ray film findings after lung expansion, further investigation for neoplastic disease is not justified. But we need to perform and chest CT and other investigation in patients with, heavy smoking, chronic bronchitis, bullous emphysema and incomplete lung expansion after chest drainage also patients with age over 50 years old. The occurrence of a pneumothorax in patients with lung cancer, worsening prognosis. Five-year survival is poor, suggesting that lung cancers present as pneumothorax at an advanced stage of disease.

Safety and Efficacy of Self-Expanding Metal Stents for Biliary Drainage in Patients Receiving Neoadjuvant Therapy for Pancreatic Cancer

Introduction: Durable biliary drainage is essential during neoadjuvant therapy (NAT) in patients with biliary obstruction from pancreas cancer. Plastic stents (PS) are associated with high occlusion rates resulting in interruptions in treatment. The aim of this study was to evaluate the safety and efficacy of self-expanding metal stents (SEMS) for biliary drainage in patients receiving NAT for pancreatic cancer. Methods: All patients referred to a tertiary center with resectable or borderline resectable (BR) pancreatic cancer and biliary obstruction were retrospectively reviewed using a prospectively maintained database. After confirming the diagnosis with EUS-FNA (on site), SEMS were deployed either as the initial biliary intervention or at the time of stent exchange in those who had prior PS. All patients who received NAT after SEMS placement were enrolled. Demographics, biliary drainage efficacy, stent dysfunction rate, procedural complications and SEMS-related reinterventions were collected. Results: From 2009 to 2014, 333 consecutive patients with resectable or BR pancreatic cancer were reviewed. Biliary drainage was required in 210 patients of which 142 (81 M, mean age 66 ± 9 years) had SEMS placed prior to starting NAT. Sixty-seven (47%) were resectable, 75 (53%) BR, 87 (61%) had prior PS exchanged to SEMS, and 115 (81%) were uncovered SEMS. The median duration from SEMS placement to the end of NAT was 111 days (range 44-282, Figure 1).Figure 1Liver function tests improved significantly after SEMS (Table 1). During NAT (median 111 days), SEMS dysfunction requiring reintervention occurred in 16 patients (11.2%) and by 282 days (maximum range of NAT) in 21 patients (14.8%;Figure 1): tissue/tumor ingrowth (11), stent occlusion from debris/food (6), stent migration (3), incomplete expansion (1), “tissue cheese-cutter” effect (1) and cystic duct obstruction (1). No difference in the rate of stent dysfunction and reinterventions was found on subgroup analysis (Table 2). There was no significant correlation between the days to SEMS related reinterventions and the duration of NAT (r2=0.05, p=0.34).Table 1: Liver function tests and tumor markers pre and post SEMS placementTable 2: Subgroup analysisConclusion: SEMS provide safe, effective and durable biliary drainage during NAT for pancreas cancer. No predictors of stent dysfunction requiring reintervention were found and there was no correlation between the duration of neoadjuvant therapy and SEMS dysfunction rate.

Interaction between the stent strut and thrombus characterized by contrast-enhanced high-resolution cone beam CT during deployment of the Solitaire stent retriever

BackgroundThe mechanism by which a stent retriever removes intraluminal thrombus from an occluded vessel in humans has not previously been studied. This study performed contrast-enhanced high-resolution cone beam CT (CE-HRCBCT)...

Pneumothorax associated with nontuberculous mycobacteria: A retrospective study of 69 patients.

The incidence of nontuberculous mycobacterial pulmonary disease (NTMPD) is increasing worldwide. Secondary spontaneous pneumothorax occurs as a complication of underlying lung disease and is associated with higher morbidity, mortality, and recurrence than primary spontaneous pneumothorax. We here investigated the clinical features and long-term outcomes of pneumothorax associated with NTMPD.We conducted a retrospective study on consecutive adult patients with pneumothorax associated with NTMPD at Fukujuji Hospital and Keio University Hospital from January 1992 to December 2013. We reviewed the medical records of 69 such patients to obtain clinical characteristics, radiological findings, and long-term outcomes, including pneumothorax recurrence and mortality.The median age of the patients was 68 years; 34 patients were women. The median body mass index was 16.8 kg/m2. Underlying pulmonary diseases mainly included chronic obstructive pulmonary disease and pulmonary tuberculosis. On computed tomography, nodules and bronchiectasis were observed in 46 (98%) and 45 (96%) patients, respectively. Consolidation, pleural thickening, interlobular septal thickening, and cavities were most common, and observed in 40 (85%), 40 (85%), 37 (79%), and 36 (77%) patients, respectively. Regarding pneumothorax treatment outcomes, complete and incomplete lung expansion were observed in 49 patients (71%) and 15 patients (22%), respectively. The survival rate after pneumothorax was 48% at 5 years. By the end of the follow-up, 33 patients had died, and the median survival was 4.4 years with a median follow-up period of 1.7 years. The rate of absence of recurrence after the first pneumothorax was 59% at 3 years. By the end of the follow-up, 18 patients had experienced pneumothorax recurrence. Furthermore, 12/18 patients (66%) with recurrent pneumothorax died during the study period. Twenty-three patients (70%) died because of NTMPD progression. Low body mass index (BMI) was a negative prognostic factor for pneumothorax associated with NTMPD in multivariate analysis (HR 0.79, 95% CI 0.64−0.96; P = 0.018)Patients with pneumothorax associated with NTMPD have advanced disease, a high rate of pneumothorax recurrence, and poor prognosis, regardless of the pneumothorax treatment used. Further improvements in early diagnosis of NTMPD and appropriate management in both NTMPD and NTMPD-associated pneumothorax are needed.

Outpatient Treatment for Pneumothorax Using a Portable Small-Bore Chest Tube: A Clinical Report.

BackgroundFor treatment of pneumothorax in Korea, many institutions hospitalize the patient after chest tube insertion. In this study, a portable small-bore chest tube (Thoracic Egg; Sumitomo Bakelite Co. Ltd., Tokyo, Japan) was used for pneumothorax management in an outpatient clinic.MethodsBetween August 2014 and March 2015, 56 pneumothorax patients were treated using the Thoracic Egg.ResultsAfter Thoracic Egg insertion, 44 patients (78.6%) were discharged from the emergency room for follow-up in the outpatient clinic, and 12 patients (21.4%) were hospitalized. The mean duration of Thoracic Egg chest tube placement was 4.8 days, and the success rate was 73%; 20% of patients showed incomplete expansion and underwent video-assisted thoracoscopic surgery. For primary spontaneous pneumothorax patients, the success rate of the Thoracic Egg was 76.6% and for iatrogenic pneumothorax, it was 100%. There were 2 complications using the Thoracic Egg.ConclusionOutpatient treatment of pneumothorax using the Thoracic Egg could be a good treatment option for primary spontaneous and iatrogenic pneumothorax.

Stabilization of numerical interchange in spectral-element magnetohydrodynamics

Auxiliary numerical projections of the divergence of flow velocity and vorticity parallel to magnetic field are developed and tested for the purpose of suppressing unphysical interchange instability in magnetohydrodynamic simulations. The numerical instability arises with equal-order C0 finite- and spectral-element expansions of the flow velocity, magnetic field, and pressure and is sensitive to behavior at the limit of resolution. The auxiliary projections are motivated by physical field-line bending, and coercive responses to the projections are added to the flow-velocity equation. Their incomplete expansions are limited to the highest-order orthogonal polynomial in at least one coordinate of the spectral elements. Cylindrical eigenmode computations show that the projections induce convergence from the stable side with first-order ideal-MHD equations during h-refinement and p-refinement. Hyperbolic and parabolic projections and responses are compared, together with different methods for avoiding magnetic divergence error. The projections are also shown to be effective in linear and nonlinear time-dependent computations with the NIMROD code Sovinec et al. [17], provided that the projections introduce numerical dissipation.

Performance analysis of a Miller cycle engine by an indirect analysis method with sparking and knock in consideration

In this paper, a full-factorial design of experiment was applied to thoroughly investigate the effects of compression ratio, intake valve closing retardation angle, and engine speed on the fuel consumption performance and power performance of the Miller cycle engine based on a quasi-dimensional simulation model. A new indirect analysis method based on formula derivation and main effect analysis was proposed to simplify the complex relationship between the design factors and the performance parameters. The definition of effective compression ratio was modified to take account of the actual mass of mixture trapped in the cylinder. The results show that the distributions of brake mean effective pressure and brake specific fuel consumption can be regarded as the re-organization results from the distributions of volumetric efficiency and indicated efficiency. The intake valve closing retardation angle has a strong negative correlation with volumetric efficiency. The modified effective compression ratio is the approximate product of the compression ratio and the volumetric efficiency, and makes obvious effects on the distribution of the indicated efficiency. Therefore the combustion process is co-evolved with the intake process in a Miller cycle engine. The further improvement of brake specific fuel consumption is mainly limited by four factors, i.e., the back flow loss, the exergy loss, the incomplete expansion loss, and the combustion loss. The improvement of fuel consumption performance is at a cost of power performance, and the trade-off between the both essentially results from the knock constraint. The engine speed makes obviously effects on both volumetric efficiency and indicated efficiency, resulting in increasing the nonlinearity of the variation of the performance parameters. However, the nonlinearity provides a possibility for a Miller cycle range extender to improve the fuel consumption performance and power performance at same time by optimizing the controlled speed.

Search for Expectancy-Inconsistent Information Reduces Uncertainty Better: The Role of Cognitive Capacity.

Motivation and cognitive capacity are key factors in people’s everyday struggle with uncertainty. However, the exact nature of their interplay in various contexts still needs to be revealed. The presented paper reports on two experimental studies which aimed to examine the joint consequences of motivational and cognitive factors for preferences regarding incomplete information expansion. In Study 1 we demonstrate the interactional effect of motivation and cognitive capacity on information preference. High need for closure resulted in a stronger relative preference for expectancy-inconsistent information among non-depleted individuals, but the opposite among cognitively depleted ones. This effect was explained by the different informative value of questions in comparison to affirmative sentences and the potential possibility of assimilation of new information if it contradicts prior knowledge. In Study 2 we further investigated the obtained effect, showing that not only questions but also other kinds of incomplete information are subject to the same dependency. Our results support the expectation that, in face of incomplete information, motivation toward closure may be fulfilled efficiently by focusing on expectancy-inconsistent pieces of data. We discuss the obtained effect in the context of previous assumptions that high need for closure results in a simple processing style, advocating a more complex approach based on the character of the provided information.

Mid- and Longer-term Follow up of Chimney and/or Periscope Grafts and Risk Factors for Failure

The aim was to report on chimney and periscope grafts (CPGs) and their mid- and longer-term outcomes when they are used to preserve reno-visceral artery (RVA) perfusion in endovascular repair of pararenal (PRAAs) or thoraco-abdominal aortic aneurysm (TAAAs). In addition, factors associated with CPG failure are presented. Limited data exist on the outcomes of CPGs, and mid- and long-term results are generally not reported. This was a prospective study in a cohort of 100 patients with PRAA (69) or TAAA (31). A total of 224 (mean 2.24 per patient) RVAs were preserved with 136 (61%) chimney and 88 (39%) periscope grafts. CPGs were constructed mainly using self expandable stent grafts. Patients were followed by clinical examination, CTA (82%), and/or duplex (18%). Data were collected until February 2015. CPG immediate technical success was 99% (222/224 branches). Mean follow up was 29 months (range 0-65; SD 17); 59% patients were followed>2 years, 30%>3 years, and 16%>4 years. Post-operatively, CPG occlusion was observed early (≤30 days) in three (1.3%) branches and during follow up in 10 (4.5%). At 36 and 48 months, the estimated primary patency was 93% and 93%. After corrective percutaneous (10) or surgical (3) re-interventions, the estimated secondary patency was 96% and 96%. Thirty day mortality was 2%; at 36 and 48 months the estimated patient survival was 79%. Significant shrinkage (72 [SD 23] vs. 62 [SD 24] mm; p<.001) was observed, with a substantial reduction (>5mm) in 55 patients, and sac enlargement in four. Incomplete aneurysm sac sealing was treated successfully by a secondary intervention in 15 patients. Self expandable CPGs have proved to be a highly successful and durable treatment for RVA preservation up to 5 years. Incomplete CPG expansion, inadequate length, and CPG use in small and diseased target arteries were risk factors for occlusion. These mid- and longer-term results support CPG use to treat PRAAs or TAAAs in patients unfit for open surgery or fenestrated/branched stent grafts.

Ewald expansions of a class of zeta-functions.

The incomplete gamma function expansion for the perturbed Epstein zeta function is known as Ewald expansion. In this paper we state a special case of the main formula in Kanemitsu and Tsukada (Contributions to the theory of zeta-functions: the modular relation supremacy. World Scientific, Singapore, 2014) whose specifications will give Ewald expansions in the H-function hierarchy. An Ewald expansion for us are given by H_{1,2}^{2,0}leftrightarrow H_{1,2}^{1,1} or its variants. We shall treat the case of zeta functions which satisfy functional equation with a single gamma factor which includes both the Riemann as well as the Hecke type of functional equations and unify them in Theorem 2. This result reveals the H-function hierarchy: the confluent hypergeometric function series entailing the Ewald expansions. Further we show that some special cases of this theorem entails various well known results, e.g., Bochner–Chandrasekharan theorem, Atkinson–Berndt theorem etc.

Pipeline Embolization Device for Large/Giant or Fusiform Aneurysms: An Initial Multi-Center Experience in Korea.

PurposeThe purpose of this study was to assess the safety and early outcomes of the Pipeline device for large/giant or fusiform aneurysms.Materials and MethodsThe Pipeline was implanted in a total of 45 patients (mean age, 58 years; M:F=10:35) with 47 large/giant or fusiform aneurysms. We retrospectively evaluated the characteristics of the treated aneurysms, the periprocedural events, morbidity and mortality, and the early outcomes after Pipeline implantation.ResultsThe aneurysms were located in the internal carotid artery (ICA) cavernous segment (n=25), ICA intradural segment (n=11), vertebrobasilar trunk (n=8), and middle cerebral artery (n=3). Procedure-related events occurred in 18 cases, consisting of incomplete expansion (n=8), shortening-migration (n=5), transient occlusion of a jailed branch (n=3), and in-stent thrombosis (n=2). Treatment-related morbidity occurred in two patients, but without mortality. Both patients had modified Rankin scale (mRS) scores of 2, but had an improved mRS score of 0 at 1-month follow-up. Of the 19 patients presenting with mass effect, 16 improved but three showed no changes in their presenting symptoms. All patients had excellent outcomes (mRS, 0 or 1) during the follow-up period (median, 6 months; range, 2-30 months). Vascular imaging follow-up (n=31, 65.9%; median, 3 months, range, 1-25 months) showed complete or near occlusion of the aneurysm in 24 patients (77.4%) and decreased sac size in seven patients (22.6%).ConclusionIn this initial multicenter study in Korea, the Pipeline seemed to be safe and effective for large/giant or fusiform aneurysms. However, a learning period may be required to alleviate device-related events.

Is high pressure postdilation safe in bioresorbable vascular scaffolds? Optical coherence tomography observations after noncompliant balloons inflated at more than 24 atmospheres.

Optical coherence tomography (OCT) was used to investigate integrity and expansion of bioresorbable drug-eluting scaffolds (BVS) after high-pressure postdilation (HPPD). Because of concerns about the risk of BVS damage, postdilation was not recommended and applied in the existing randomized studies and most registries. Recent real world data suggest incomplete BVS expansion cause higher rates of thrombosis. In vivo confirmation of the safety of high pressure postdilation is of paramount importance. Data from final OCT examination of consecutive implanted BVS, postdilated with noncompliant (NC) balloons at pressure ≥24 atm were analyzed. The following stent performance indices were assessed with OCT: mean and minimal lumen and scaffold area, residual area stenosis (RAS), incomplete strut apposition (ISA), tissue prolapse, eccentricity index (EI), symmetry index (SI), strut fractures, and edge dissections. Twenty-two BVS postdilated at high pressure were analyzed. The average maximal postdilation balloon inflation (maxPD) was 28 ± 3 atm. High pressure OPN NC Balloon (SIS Medical AG, Winterthur Switzerland) was used in 41% of postdilations with a maximal PD of 30 ± 4.7 atm. Final mean and minimal lumen area were 6.8 ± 1.4 and 5.5 ± 1.4 mm(2) , respectively. OCT showed low percentage of RAS (16 ± 9.6%), and low percentage of ISA (1.8 ± 2.4%). Mean EI was 0.86 ± 0.02 and SI 0.35 ± 0.14. OCT analysis showed one edge dissection and no scaffold fractures. BVS deployment optimization using HPPD does not cause BVS disruption and is associated with a good BVS expansion, low rate of strut malapposition and edge dissections.

Leaflet stress and strain distributions following incomplete transcatheter aortic valve expansion

Transcatheter aortic valve replacement (TAVR) is an established treatment alternative to surgical valve replacement in high-risk patients with severe symptomatic aortic stenosis. The current guidelines for TAVR are to upsize transcatheter aortic valve (TAV) relative to the native annulus to secure the device and minimize paravalvular leakage. Unlike surgical stented bioprosthetic valves where leaflets are attached to a rigid frame, TAVs must expand to fit within the native annulus. Fully-expanded circular TAVs have consistent leaflet kinematics; however, subtle variations in the degree of stent expansion may affect leaflet coaptation. The objective of this study was to determine the impact of incomplete TAV expansion on leaflet stress and strain distributions. In this study, we developed finite element models of a 23mm homemade TAV expanded to diameters ranging from 18 to 23mm in 1mm increments. Through dynamic finite element simulations, we found that leaflet stress and strain distributions were dependent on the diameter of the inflated TAV. After complete expansion of the TAV to 23mm, high stress and strain regions were observed primarily in the commissures during diastole. However, 2–3mm incomplete TAV stent expansion induced localized high stress regions within the TAV commissures, while 4–5mm incomplete stent expansion induced localized high stress regions within the belly of the TAV leaflets during the diastolic phase of the cardiac cycle. Increased mechanical stress and flexural deformation on TAV leaflets due to incomplete stent expansion may lead to accelerated tissue degeneration and diminished long-term valve durability.

Surgery for localized pulmonary mycotic infections in patients with hematopoietic disorder

BackgroundSurgical resection is considered to be the most effective treatment for localized pulmonary mycotic infections. However it is also a particularly challenging procedure because it is associated with considerable mortality and morbidity. Furthermore, hematopoietic disorders usually cause immunosuppression, anemia, and coagulopathy, which are definite risk factors for surgery. The purpose of this study is to evaluate the surgical outcomes of pulmonary mycotic infections in hematopoietic disorder patients.MethodsBetween 2011 and 2013, 23 patients underwent surgical treatment for pulmonary mycotic infections at a single institution. The patients were divided into two groups; Group A (hematopoietic disorder patients, n = 9) and Group B (n = 14). We retrospectively reviewed medical and radiologic data.ResultsThe complex type was more frequent in group A (66.6 %) than in group B (35.7 %). Postoperatively, there was no mortality. However, morbidity was 22.2 % (2 incomplete expansion) in group A, and 35.6 % (1 prolonged air leak, 3 bleeding, 1 Bronchopleural fistula) in group B. The difference in morbidity between the groups did not show any statistical significance (p = 0.657) as well as duration of chest tube drainage, and postoperative hospital stay. The hematopoietic disorder patients did not impose a risk factor for morbidity and mortality.ConclusionsAlthough hematopoietic disorder patients have many surgical risk factors, the surgical treatment of pulmonary mycotic infections produces very acceptable outcomes in selected cases.

Value of C-Arm Computed Tomography to Evaluate Stent Deployment During Femoro-Popliteal Revascularization

To compare the accuracy of C-arm computed tomography (CT) and digital subtraction angiography (DSA) in detecting incomplete stent expansion (ISE) after superficial femoral artery (SFA) stenting using intravascular ultrasound (IVUS) as a gold standard. Fifty patients with symptomatic SFA occlusive disease requiring angioplasty were prospectively included. Once technical success (<30 % residual stenosis) was obtained on post-procedural DSA, C-arm CT and IVUS were acquired. DSA and C-arm CT examinations were reviewed by 2 investigators and correlated with IVUS. C-arm CT image quality was rated on a four-point scale. Doppler ultrasound was performed at 1-year follow-up. The ankle-brachial index was 0.69 ± 0.10 and 0.99 ± 0.40, respectively, pre- and post-procedure. C-arm CT imaging quality was rated as good or excellent in 80%. In-stent minimal luminal diameter (MLD) was evaluated at 4.71 ± 0.7 mm on DSA, 3.39 ± 0.6 mm on IVUS, and 3.12 ± 0.9 mm on C-arm CT. Compared to IVUS, DSA demonstrated an overestimation of MLD (p = 0.0001), an underestimation of ISE (DSA = 18.8% ± 7.6; IVUS = 29.8% ± 9) (p < 0.0001), and a poor inter-technique intra-class correlation coefficient (ICC = 0.24). No difference was observed between IVUS and C-arm CT in ISE as calculated by diameter (29.8 ± 9 vs. 28.2 ± 12.5%, p = 0.5) and area (30.2 ± 8.4 vs. 33.3 ± 9.5%, p = 0.2). Inter-technique ICC between C-arm CT and IVUS was 0.72 [95%CI 0.49; 0.85] for MLA measurements. The inter-observer ICC for MLD and MLA measurements on C-arm CT were, respectively, estimated at 0.75 [95% CI 0.40, 0.89] and 0.77 [95% CI 0.43, 0.90)]. C-arm CT presents a better correlation with IVUS than DSA to determine lumen diameter and ISE immediately after percutaneous revascularization.