TA Procedure Research Articles

Diagnostic accuracy of endoscopic ultrasonography-guided tissue acquisition prior to resection of pancreatic carcinoma: a nationwide analysis

IntroductionEndoscopic ultrasonography guided tissue acquisition (EUS + TA) is used to provide a tissue diagnosis in patients with suspected pancreatic cancer. Key performance indicators (KPI) for these procedures are rate of adequate sample (RAS) and sensitivity for malignancy (SFM). Aim: assess practice variation regarding KPI of EUS + TA prior to resection of pancreatic carcinoma in the Netherlands. Patients and methodsResults of all EUS + TA prior to resection of pancreatic carcinoma from 2014–2018, were extracted from the national Dutch Pathology Registry (PALGA). Pathology reports were classified as: insufficient for analysis (b1), benign (b2), atypia (b3), neoplastic other (b4), suspected malignant (b5), and malignant (b6). RAS was defined as the proportion of EUS procedures yielding specimen sufficient for analysis. SFM was calculated using a strict definition (malignant only, SFM-b6), and a broader definition (SFM-b5+6). Results691 out of 1638 resected patients (42%) underwent preoperative EUS + TA. RAS was 95% (range 89–100%), SFM-b6 was 44% (20–77%), and SFM-b5+6 was 65% (53–90%). All centers met the performance target RAS>85%. Only 9 out of 17 met the performance target SFM-b5+6 > 85%. ConclusionThis nationwide study detected significant practice variation regarding KPI of EUS + TA procedures prior to surgical resection of pancreatic carcinoma. Therefore, quality improvement of EUS + TA is indicated.

How Large a Study Is Needed to Detect TKA Revision Rate Reductions Attributable to Robotic or Navigated Technologies? A Simulation-based Power Analysis.

How Large a Study Is Needed to Detect TKA Revision Rate Reductions Attributable to Robotic or Navigated Technologies? A Simulation-based Power Analysis.

Therapeutic apheresis during pregnancy: A single center experience

IntroductionTherapeutic apheresis (TA) represents a treatment option for pre-existing conditions or diseases occurring during gestation. Although pregnancy is not a contraindication per se, due to the lack of evidence-based guidelines and presumed risk of maternal/fetal adverse events there is a general resistance to its application. Material and methodsBetween January 2005 and August 2017, at the Apheresis Unit of the University Hospital of Padua 936 TA procedures were performed during 57 pregnancies in 48 patients: 813 Plasma Exchange sessions, 119 Immunoadsorptions, 4 Red Blood Cell exchanges. The treated disease were as follows: antiphospholipid syndrome (18 patients), autoimmune congenital heart block (18), myasthenia gravis (3), Rh alloimmunization (2), systemic sclerosis (1), suspected autoimmune encephalitis (1), severe hypertriglyceridaemia (1), post partum hemolytic-uremic syndrome (1), sickle cell disease (1), lupus nephritis (1) and thrombotic thrombocytopenic purpura (1). ResultsIn the time period considered the apheresis sessions applied to pregnant women were 7.1% of the total (n = 13.251). The median age at the first treatment was 33 years. The median week of gestation (WG) at the beginning of treatments was 21. Twenty (2.1%) sessions were complicated by adverse events, none requiring or prolonging hospitalization. There were 50 live births, 5 spontaneous abortions and 2 voluntary terminations of pregnancy. Median WG at delivery was 35 and caesarean section was performed in 46 cases. ConclusionsOur data showed that TA in pregnancy is well tolerated. Close collaboration between clinician, obstetrician and TA specialist is crucial to ensure a good outcome of high-risk pregnancies.

Efficacy and safety of transcatheter valve-in-valve replacement for Mitroflow bioprosthetic valve dysfunction.

Bioprostheses with pericardial leaflets mounted externally on the stent pose a high risk for valve-in-valve (ViV) procedures. This study analyzed the efficacy and safety of ViV procedures for treating structural valve deterioration (SVD) in Mitroflow bioprostheses. Between January 2012 and August 2017, 11 patients (mean age 80.3 ± 5.6 years) were treated for SVD of Mitroflow bioprostheses with transcatheter ViV procedures (six transapical [TA] and five transfemoral [TF]) using balloon expandable bioprostheses. All patients but one were in NYHA class III-IV. Mean STS PROM, euroSCORE I, and euroSCORE II were 8 ± 6.5%, 27.8 ± 11.5%, and 12 ± 5.9%, respectively. Two patients had a "porcelain aorta." The size of implanted valves were 23 mm in 10 cases and 26 mm in one case. One patient suffered a coronary occlusion during a TF approach. The mean volume of contrast used in TF implants was 163 ± 69.8 mL. No contrast media were used in TA procedures. There was one in-hospital death (10%). At 1 year of follow-up, peak and mean aortic gradients were 25.5 ± 5.8 mmHg and 15.5 ± 5.7 mmHg, respectively. One patient had mild paravalvular regurgitation. Cumulative survival was 90.9% at 1 year, 70.7% at 2 years, and 53% at 3 years. ViV procedures with balloon-expandable aortic valves provide good hemodynamic and clinical mid-term results for treating patients with a degenerated Mitroflow aortic bioprosthesis. Special care must be taken in small aortic roots, when the stented valve is in the supra-annular position to avoid coronary ostial obstruction.

Conventional surgery and transcatheter closure via surgical transapical approach for paravalvular leak repair in high-risk patients: results from a single-centre experience.

Paravalvular leaks (PVL) occur in up to 17% of all surgically implanted prosthetic valves. Re-operation is associated with high morbidity and mortality. Transcatheter closure via a surgical transapical approach (TAp) is an emerging alternative for selected high-risk patients with PVL. The aim of this study was to compare the in-hospital outcomes of patients who underwent surgery and TA-closure for PVL in our single-centre experience. From October 2000 to June 2013, 139 patients with PVL were treated in our Institution. All the TA procedures were performed under general anaesthesia in a hybrid operative room: in all but one case an Amplatzer Vascular Plug III device was utilized. Hundred and thirty-nine patients with PVL were treated: 122 patients (87.3%) underwent surgical treatment (68% mitral PVL; 32% aortic PVL) and 17 patients (12.2%) underwent a transcatheter closure via a surgical TAp approach (all the patients had mitral PVL; one case had combined mitral and aortic PVLs); in 35% of surgical patients and in 47% of TAp patients, multiple PVLs were present. The mean age was 62.5 ± 11 years; the Logistic EuroScore was 15.4 ± 3. Most of the patients were in New York Heart Association (NYHA) functional class III-IV (57%). Symptomatic haemolysis was present in 35% of the patients, and it was particularly frequent in the TAp (70%). Many patients had >1 previous cardiac operation (46% overall and 82% of TAp patients were at their second of re-operation). Acute procedural success was 98%. In-hospital mortality was 9.3%; no in-hospital deaths occurred in patients treated through a TAp approach. All the patients had less than moderate residual valve regurgitation after the procedure. Surgical treatment was identified as a risk factor for in-hospital death at univariate analysis (OR: 8, 95% CI: 1.8-13; P = 0.05). Overall actuarial survival at follow-up was 39.8 ± 7% at 12 years and it was reduced in patients who had >1 cardiac re-operation (42 ± 8 vs. 63 ± 6% at 9 years; P = 0.009). A transcatheter closure via a surgical TAp approach appears to be a safe and effective therapeutic option in selected high-risk patients with PVL and is associated with a lower hospital mortality than surgical treatment, in spite of higher predicted risk. Long-term survival remains suboptimal in these challenging patients.

Transcatheter aortic valve replacement: Experience with the transapical approach, alternate access sites, and concomitant cardiac repairs

Transapical transcatheter aortic valve replacement (TA-TAVR) is a viable treatment option for selected high-risk elderly patients. We analyzed the 30-day mortality and perioperative complications, focusing on the "learning curve" since our first TA procedure in 2007. We also introduce unique cases, demonstrating new possibilities for alternate access sites and concurrent cardiac interventions using the apical approach. From February 2007 to May 2013, 150 patients underwent TA-TAVR (mean age, 81.4 ± 7 years; mean Society of Thoracic Surgeons score, 9.8±3.5). We compared 2 groups (group A, n=65, procedures from February 2007 to December 2010; group B, n=85, procedures from January 2011 to May 2013). Five deaths (3.3%) occurred within 30 days, with a decrease in 30-day mortality between the 2 groups (group A, n=4, 6.2%; group B, n=1, 1.2%) that became significant at 1 year (log-rank, P=.002). Severe bleeding from the apex (group A, 4.6%; group B 4.4%) and deployment of >1 valve (group A, 7.6%; group B, 10.5%) was similar in both groups. Valve embolization was less frequent in group B (group A, 4.6%; group B, 2.4%). Postoperative complications in groups A and B included stroke (3.1% vs 0%), renal failure (9.3% vs 4.7%), and permanent pacemaker implantation (6.1% vs 5.9%). No myocardial infarctions occurred in either group. Two patients received simultaneous aortic and mitral valve implantation; 1 patient undergoing TA-TAVR also underwent distal arch and descending aorta repair; all had favorable outcomes. With a further 25 TA-TAVR since May 2013, the overall mortality is 2.9% (5/175). Although working with the fragile apical tissues in high-risk elderly patients remains a challenge, we have demonstrated a reduction in mortality and complications with increasing experience in TA-TAVR. We have successfully demonstrated novel combined procedures and uses for the transapical approach and alternate access sites, which should continue to be explored.

Comparison 30-day clinical complications between transfemoral versus transapical aortic valve replacement for aortic stenosis: a meta-analysis review

BackgroundSince 2002, transapical aortic valve replacement has been developed as a clinical pathway for transcatheter aortic valve implantation (TAVI). However the appropriate role of TA in the AS population versus TF remains unclear. We performed a meta-analysis to assess if TF has any benefit in reduction of 30-day clinical complications in AS.MethodsWe conducted a comprehensive search on pub-med and web of knowledge from 2002 through September 2012 using following terms: aortic stenosis, aortic valve replacement, transcatheter aortic valve implantation, TAVI, trans-artery, transfemoral, trans-apical. Studies in the original research or review articles were also considered. Included studies must meet the preconditioned criterias. Two investigators independently browsed the studies by title and abstract, finally making decision according to full-text. Disagreements were discussed in group.ResultsA total of 20 studies met inclusion criteria’s and were included in the analysis (including 4267 patients in TF group, 2242 in TA group). No random clinical trial, one was a retrospective study, others were prospective trials. Our meta-analysis found that TF had the low incidence of 30-day mortality compared with TA procedure (7.5% versus 11.3%). The incidence of stroke at ≤ 30 days was relatively low (3.8% in TF versus 4.0% in TA). Although the incidence of post-operative heart block was high (8.5% versus 7.5%), but no differences were indicated [1.06,95% CI(0.85,1.33)].ConclusionsThe result of our meta-analysis suggested that TF may have a low risk for 30-day mortality against TA procedure. No difference was found in the incidence of post-operative stroke and heart block.

From invited to uninvited participation (and back?): rethinking civil society engagement in technology assessment and development

In recent years, citizens’ and civil society engagement with science and technology has become almost synonymous with participation in institutionally organized formats of participatory technology assessment (pTA) such as consensus conferences or stakeholder dialogues. Contrary to this view, it is argued in the article that beyond these standardized models of “invited” participation, there exist various forms of “uninvited” and independent civil society engagement, which frequently not only have more significant impact but are profoundly democratically legitimate as well. Using the two examples of patient associations and environmental and consumer organizations in the field of nanotechnology, it is illustrated that interest-based civil society interventions do play an important role in the polycentric governance of science and technology. In conclusion, some implications for the activities of TA institutions and the design of novel TA procedures are outlined.

Directivity Computation by Spherical Spiral Scanning in Near Field Region

A procedure for evaluating the directivity of an antenna under test from near-field measurements on a spherical scanning surface is proposed. It uses a formula in closed form for computing the total radiated power from the knowledge of the radiation intensity samples on the far-field sphere. These last are determined via an efficient probe compensated near-field–far-field transformation technique based on a nonredundant sampling representation of the probe voltage. The samples are collected on a spiral wrapping the near-field spherical surface from pole to pole. With respect to the classical spherical scanning, this innovative way of collecting the data allows the reduction of the time required for the samples acquisition by means of a continuous movement of the positioning systems. The effectiveness of the proposed procedure is assessed by numerical simulations.

Efficient Numerical Techniques for Solving Pocklington's Integral Equation Using Multiwavelets

A procedure is presented for solving the electric field integral equation for a thin wire. The method is based upon Alpert multiwavelets functions approximation. The properties of Alpert multiwavelets are first given. These wavelets are utilized to reduce the solution of Pocklington's integral equation to the solution of sparse algebraic equations. In order to save memory requirement and computation time, a threshold procedure is applied to obtain sparse algebraic equations. Through numerical examples, performance of the present method is investigated concerning the convergence and the sparseness of the resulted matrix equation.

Chemical modification of styrene–butadiene–styrene (SBS) rubber by reactive grafting with maleic anhydride

A procedure to increase the adhesion of block styrene-butadiene-styrene (SBS) rubber consisting of the reactive grafting with maleic anhydride (MA) in the presence of an organic peroxide radical initiator is proposed. The influence of the reactive grafting on the surface properties of SBS has been studied with special emphasis on the improvement of the adhesion to polyurethane adhesive. The grafting of MA onto SBS was carried out in the presence of different concentrations of 2,5-dimethyl-2,5-di(tertbutyl peroxy) hexane (DBPH) as initiator to generate oxygen radicals by thermal decomposition, which induce the grafting reaction. The modification process was performed in the molten state using a Brabender mixer to premix the reactants and a hot press to initiate the functionalizing reaction. ATR-IR and XPS spectroscopies were employed to verify the grafting of MA on SBS. The changes in wettability on the modified SBS rubber were determined by contact angle measurements. Adhesion properties were evaluated from T-peel tests of SBS rubber/polyurethane adhesive joints. Reasonable extents of MA grafting on SBS were obtained (evidenced by the presence of a weak carbonyl vibration at 1700 cm-1 in the ATR-IR spectra and by the carbon- oxygen band at a binding energy of 287.0 eV in the XPS spectra). The higher the DBPH amount, the higher the MA amount grafted onto the SBS surface. The maximum grafting level was obtained using 2 wt% MA. Grafted species seemed to be mainly concentrated on the surface of the SBS-molded sheets. The wettability of the modified rubber increased with respect to the original polymer, new carbon-oxygen moieties were created and the C/O ratio increased. A noticeable enhancement in peel strength values was observed, which was ascribed to the creation of interfacial interactions between the polyurethane and the SBS rubber surfaces.

Implications of maternal serum alpha-fetoprotein elevation caused by transabdominal and transcervical CVS.

Of 2882 women allocated to either transabdominal CVS (TA) or transcervical CVS (TC) at two large obstetric centres in Denmark, 2707 had blood samples drawn before and 30 min after CVS for maternal serum-alpha-fetoprotein (MSAFP) measurement. 2535 of these women had cytogenetically normal pregnancies and 2091 of them went on to have samples drawn at the 18-20 week follow-up. Post-procedure MSAFP values were correlated to the biopsy method used, with mean MSAFP values significantly higher after TA than TC, 33 and 15 kU/l, respectively (P < 0.001). Following TA procedures, 18 per cent of cases had feto-maternal transfusion higher than 0.1 ml; this occurred in only 5 per cent of TC cases. MSAFP levels were associated with spontaneous fetal loss in the TA group but not in the TC group. TC, however, was followed by more losses than TA. The post-CVS MSAFP value was positively correlated with the amount of villi aspirated. The difference in post-procedure elevation in MSAFP 30 min later (average 18 kU/l higher for TA than for TC) was not reflected in raised levels at the 18-20 week follow-up. Study medians at mid-trimester did not differ from reference group medians established from a group of singleton pregnancies with sonographically determined gestational age who did not experience invasive procedures and delivered normal infants. Our findings suggest that CVS does not compromise mid-trimester MSAFP for screening for neural tube defects (NTDs). Extremely high mid-trimester MSAFP values in the TC group could predict imminent loss.

Recovery of the auditory brainstem response by sign-bit and conventional averaging.

In evoked potential studies, such as measurement of the auditory brainstem response (ABR), the signal of interest is recovered from the noise background by averaging at least 1000 EEG segments, recorded in phase, with a repeated auditory signal. The possibility is examined that information about whether each sample point was positive or negative relative to a baseline (i.e., averaging the sign bit) would allow recovery of the ABR for clinical purposes. A demonstration is presented in which auditory brainstem responses based on the full 12 bits of a typical analog-to-digital converter (TA or true amplitude procedure) are compared to those based on a single bit (SB procedure). For the signal-to-noise (S/N) ratios associated with an ABR signal in EEG noise (i.e., in the range 0.01>or=S/N>or=0.5), the recovery of the ABR signal using the SB procedure is quite satisfactory. Since the SB procedure is much less demanding computationally than the TA procedure, and thus faster and less expensive, it could be useful for practical ABR recovery. >

Applying technology assessment in the multi-product company

With the Technology Assessment Act becoming law in the USA, a mechanism was set into motion which will have wide repercussions in every industry: any major innovation has to be appropriately evaluated before it can be introduced on the US market. In this article, technological assessment is approached from a manufacturing company viewpoint and seen as a specific application of technological forecasting techniques. The author presents a detailed account of a typical TA procedure composed of three separate assessments—economic, ecological and consumer—of a single product.