Fabrication and in-vitro characterization of a polymeric aortic valve for minimally invasive valve replacement.

The valve replacement therapy is the standard treatment for severe heart valve diseases. Nowadays, two types of commercial prosthesis are available: mechanical and biological, but both of them have severe limitations. Moreover, alternative therapeutic approach for valve replacement, based on minimally invasive techniques (MIAVR), motivates the search for new valve materials. In this study a polyurethane-based self-expandable tri-leaflets heart valve compatible with MIAVR procedure is proposed. The device is based on the development, fabrication and characterization of three different elements: the leaflets, the polymeric stent for supporting the leaflets, and the external metallic stent for anchoring the valve to the native aortic root. The polymeric stent and the valve leaflets were fabricated using a thermoplastic silicone-polycarbonate-urethane using 3D printing and spray technology while the external metallic stent was made in nickel titanium (Nitinol) to obtain a self-expandable valve after the crimping process. The three elements were assembled in the completed device and tested by crimping, fatigue and fluid-dynamic test. The novel polymeric valve proposed showed promising results about valve crimping capabilities, durability and fluid dynamic performances. This approach could offer advantages such as low cost and to produce a tailor-made device basing on patient's imaging data. Moreover, the selected biomaterial offers the potential to have a device that could need of permanent anticoagulation and lack of calcification.

A Proof of Concept of a Non-Invasive Image-Based Material Characterization Method for Enhanced Patient-Specific Computational Modeling.

PURPOSE: Computational models of cardiovascular structures rely on their accurate mechanical characterization. A validated method able to infer the material properties of patient-specific large vessels is currently lacking. The aim of the present study is to present a technique starting from the flow-area (QA) method to retrieve basic material properties from magnetic resonance (MR) imaging. METHODS: The proposed method was developed and tested, first, in silico and then in vitro. In silico, fluid-structure interaction (FSI) simulations of flow within a deformable pipe were run with varying elastic modules (E) between 0.5 and 32 MPa. The proposed QA-based formulation was assessed and modified based on the FSI results to retrieve E values. In vitro, a compliant phantom connected to a mock circulatory system was tested within MR scanning. Images of the phantom were acquired and post-processed according to the modified formulation to infer E of the phantom. Results of in vitro imaging assessment were verified against standard tensile test. RESULTS: In silico results from FSI simulations were used to derive the correction factor to the original formulation based on the geometrical and material characteristics. In vitro, the modified QA-based equation estimated an average E = 0.51 MPa, 2% different from the E derived from tensile tests (i.e. E = 0.50 MPa). CONCLUSION: This study presented promising results of an indirect and non-invasive method to establish elastic properties from solely MR images data, suggesting a potential image-based mechanical characterization of large blood vessels.

Effects of Adjuvant Chemotherapy on Cognitive Function of Patients With Early-stage Colorectal Cancer.

PURPOSE: Chemotherapy-related cognitive impairment can occur in cancer survivors after treatment, especially those patients who have undergone chemotherapy for breast cancer. The frequency and to what extent such toxicity develops in colorectal cancer (CRC) survivors is unknown. The present prospective study evaluated the effects of adjuvant chemotherapy on the cognitive performance of patients with localized CRC compared with a control group who had not undergone chemotherapy. PATIENTS AND METHODS: Consecutive patients with localized stage II and III CRC completed neuropsychological assessments, self-reported cognitive complaint questionnaires, and depressive symptom evaluations before starting fluoropyrimidine-based adjuvant chemotherapy and after 12 months. Blood was collected for apolipoprotein E genotyping. Diffusion tensor imaging data were acquired from a subset of participants at both evaluation points. RESULTS: From December 2012 to December 2014, 137 patients were approached and 85 were included. Of these 85 patients, 49 had undergone chemotherapy and 26 had not, in accordance with the standard recommendations for adjuvant therapy for CRC. The mean age was 62.5 ± 9.4 years, 60% were men, and the mean educational attainment was 7.6 ± 3.7 years. No difference was found in the global composite score (P = .38), attention (P = .84), or memory (P = .97) between the 2 groups during the follow-up period (mean ± standard deviation, 375 ± 29 days). However, a statistically significant difference was found for executive function after adjustment for age, sex, education, and depressive symptoms at baseline (ß -1.80; 95% confidence interval, -3.50 to -0.11; P = .04), suggesting worse performance for the chemotherapy group. For the 32 patients who had undergone magnetic resonance imaging, tract-based spatial statistics did not show voxelwise significant differences in structural brain connectivity at baseline or during follow-up. Apolipoprotein E polymorphisms were not predictive of cognitive dysfunction. CONCLUSION: Patients with CRC who received adjuvant 5-fluorouracil with or without oxaliplatin presented with a decline in executive function after 12 months compared with patients with localized disease who had not received chemotherapy.

Corpus callosum diffusion abnormalities in refractory epilepsy associated with hippocampal sclerosis.

OBJECTIVES: To detect by diffusion tensor imaging (DTI) the extent of microstructural integrity changes of the corpus callosum (CC) in patients with hippocampal sclerosis (HS) and to evaluate possible association with clinical characteristics. METHODS: Fourty-two patients with temporal lobe epilepsy (TLE) and HS and 30 control subjects were studied with DTI. We grouped patients according to lesion side (left or right) HS. Mean diffusivity (MD), fractional anisotropy (FA), radial (RD) and axial diffusivity (AD) were extracted from five segments in CC midsagittal section obtained by automatic segmentation. CC DTI findings were compared between groups. We also evaluated association of DTI changes and clinical characteristics. RESULTS: HS patients displayed decreased FA and increased MD and RD in the anterior, mid-posterior and posterior CC segments, compared to controls. No differences were observed in AD. Patients reporting febrile seizure as the initial precipitating event presented more intense diffusion changes. No differences were seen comparing left and right HS. Age at epilepsy onset, disease duration and seizure frequency were not associated with DTI findings. CONCLUSIONS: This is one of the largest series of TLE-HS patients evaluating CC white matter fiber integrity by DTI, which allowed us to study how some clinical characteristics, such as seizure frequency, disease duration and lesion side, are related to CC integrity. Occurrence of febrile seizure was the only factor that had significant impact on tract integrity. Diffusion changes were not restricted to the posterior part of the CC; we observed the same changes for the anterior part of the CC. Diffusion changes were characterized by an increase in RD, while the AD remained intact for all regions of the CC.

DTI-based tractography of the arcuate fasciculus in patients with polymicrogyria and language disorders.

OBJECTIVES: To assess the integrity of the arcuate fasciculus (AF) with diffusion tensor imaging (DTI) and tractography in patients with congenital polymicrogyria (PMG) and language disorders. METHODS: Twelve patients with PMG and 12 matched controls were prospectively evaluated with DTI (32 gradient encoding directions, b-value=1000 s/mm(2)) at 3.0T. The AF was virtually dissected with a deterministic streamline approach. DTI metrics included FA (fractional anisotropy), mean diffusivity (MD), axial diffusivity (AD) and radial diffusivity (RD). A subset of patients (n=4) was evaluated to assess cognitive performance and language skills. RESULTS: Qualitative evaluation revealed several abnormalities in tracts size and architecture in nearly all PMG patients. Remarkably, in 3 patients with bilateral PMG, the AF was not delineated on both hemispheres. In comparison to controls, patients exhibited significant decrease of FA (p=0.003) in addition to increase of RD (p=0.03) in the right AF, whereas there was significant increase of MD in the left AF (p=0.04). All 4 patients with language evaluation had suboptimal performance on lexical fluency and prosodic linguistic. CONCLUSIONS: DTI and tractography suggest that the AF is severely disrupted in patients with PMG, providing an anatomical in vivo substrate for the language disorders commonly associated with these cortical malformations.

Diffusion abnormalities of the corpus callosum in patients with malformations of cortical development and epilepsy.

PURPOSE: Diffusion tensor imaging (DTI) is a magnetic resonance imaging (MRI) technique that can characterize white matter (WM) architecture and microstructure. DTI has demonstrated extensive WM changes in patients with several epileptic syndromes, but few studies have focused on patients with malformations of cortical development (MCD). Our aim was to investigate the quantitative diffusion properties of the corpus callosum (CC), a major commissural bundle critical in inter-hemispheric connectivity, in a large group of patients with MCD. METHODS: Thirty-two MCD patients and 32 age and sex-matched control subjects were evaluated with DTI at 3.0 T. We analyzed the three major subdivisions of the CC (genu, body, and splenium) with deterministic tractography to yield fractional anisotropy (FA), mean diffusivity (MD), parallel diffusivity (λ||) and perpendicular diffusivity (λ⊥). We further assessed the CC with region of interest (ROI)-based analyses and evaluated different subgroups of MCD (polymicrogyria/schizencephaly, heterotopia, and cortical dysplasia). Partial correlations between diffusion changes and clinical parameters (epilepsy duration and age at disease onset) were also queried. RESULTS: There were significant reductions of FA, accompanied by increases in MD and λ⊥ in all segments of the CC in the patients group with both analytical methods. The absolute differences in FA were greater on ROI-analyses. There were no significant differences between the MCD subgroups, and no correlations between clinical parameters of epilepsy and FA. CONCLUSIONS: Our study indicates DTI abnormalities consistent with microstructural changes in the corpus callosum of MCD patients. The findings support the idea that patients with epilepsy secondary to cortical malformations present widespread WM changes that extend beyond the macroscopic MRI-visible lesions.

Phosphorus magnetic resonance spectroscopy in malformations of cortical development.

PURPOSE: The aim of this study was to evaluate phospholipid metabolism in patients with malformations of cortical development (MCDs). METHODS: Thirty-seven patients with MCDs and 31 control subjects were studied using three-dimensional phosphorus magnetic resonance spectroscopy ((31)P-MRS) at 3.0 T. The voxels in the lesions and in the frontoparietal cortex of the control subjects were compared (the effective volumes were 12.5 cm(3)). Robust quantification methods were applied to fit the time-domain data to the following resonances: phosphoethanolamine (PE); phosphocholine (PC); inorganic phosphate (Pi); glycerophosphoethanolamine (GPE); glycerophosphocholine (GPC); phosphocreatine (PCr); and α-, ß-, and γ-adenosine triphosphate (ATP). We also estimated the total ATP (ATP(t) = α-+ß-+γ-ATP), phosphodiesters (PDE = GPC+GPE), phosphomonoesters (PME = PE+PC), and the PME/PDE, PCr/ATP(t) and PCr/Pi ratios. The magnesium (Mg(2+)) levels and pH values were calculated based on PCr, Pi, and ß-ATP chemical shifts. KEY FINDINGS: Compared to controls and assuming that a p-value < 0.05 indicates statistical significance, the patients with MCDs exhibited significantly lower pH values and higher Mg(2+) levels. In addition, the patients with MCDs had lower GPC and PDE and an increased PME/PDE ratio. SIGNIFICANCE: Mg(2+) and pH are important in the regulation of bioenergetics and are involved in many electrical activity pathways in the brain. Our data support the idea that neurometabolic impairments occur during seizure onset and propagation. The GPC, PDE, and PME/PDE abnormalities also demonstrate that there are membrane turnover disturbances in patients with MCDs.

Anisotropic AAA: computational comparison between four and two fiber family material models.

Abdominal aortic aneurysm (AAA) is a cardiovascular disease with high incidence among elderly population. Biomechanical computational analyses can provide fundamental insights into AAA pathogenesis and clinical management, but modeling should be sufficiently accurate. Several constitutive models of the AAA wall are present in the literature, and some of them seem to well describe the experimental behavior of the aneurysmatic human aorta. In this work we compare a two (2FF) and a four (4FF) fiber families constitutive models of the AAA wall. Both these models satisfactorily fit literature data from biaxial tests on the aneurysmatic tissue. To investigate the peculiar characteristics of these models, we considered the problem of AAA inflation, and solved it by implementing the constitutive equations in a finite element code. A 20% axial stretch was imposed to the aneurysm ends, to simulate the physiological condition. Although fitted on the same dataset, the two material models lead to considerably different outcomes. In particular, adopting a 4FF strain energy function (SEF), an increase of the circumferential stress values can be observed, while higher axial stresses are recorded for the 2FF model. These differences can be attributed to the intrinsic characteristics of the SEFs and to the effective stress field, with respect to the one experienced in biaxial experimental tests on which the fitting is based. In fact the two SEFs appear similar within the region of the stress-strain experimental data, but become different outside it, as in case of aneurysms, due to the effects of the data extrapolation process. It is suggested that experimental data should be obtained for conditions similar to those of the application for which they are intended.

[Surgical treatment of acute colonic diverticulitis. Personal experience]. / Il trattamento chirurgico della diverticolite acuta del colon. Esperienza personale.

BACKGROUND: Colonic acute diverticulitis presents in patients that suffered from colonic diverticula in 10-25% of cases higher percentage in the elder patient. Colonic acute diverticulitis mortality leads high rates in over 70 years old patients with a value a upper than 75-80%. Perforation and diffuse peritonitis are the more serious complications. Accurate clinical staging followed by correct surgical option are the base of the therapeutical success. METHODS: Between january 1995 and june 2000 we studied by a retrospective analysis 56 patients (34M/22F), mean age 67, hospitalized cause acute perforate colonic diverticulitis, all patients were recorded in order their clinical conditions APS score and Hinchey staging of the disease. At the time of the recovery all patients underwent at clinical examination, abdominal ultrasound, plane X-ray, and bloody tests. Surgical operations performed were: PRA; PRA and protective colostomy; Hartmann procedure. In the patients with APS score > 6-10 and aged > 70 Hartmann procedure was performed. RESULTS: Overall mortality was 9% (5 pazienti), overall morbility was 40%. On the basis of the I and II Hinchey stage mortality rate was 0%. In the III stage was recorded mortality of 4% and 33% in IV stage. Complication were: 6 anastomotic lekage; 7 infections of the laparotomic wound; 1 incisional hernia; 2 lekeages of the stomoa; 3 stomatitis; 5 proctitis. CONCLUSION: Therapeutical choise treatment has to consider Hinchey stage and APS score. Hartmann procedure is indicated in stage III-IV with score APS > 8-10. For the other patients primary resection anastomosis and if is necessary associated colostomy is the treatment recommended.

[Palliative treatment of neoplasms of the bilio-pancreatic area. Surgical diversion treatment versus endoscopic-percutaneous approach]. / Trattamento palliativo delle neoplasie del distretto bilio-pancreatico. Terapia derivativa chirurgica versus approccio endoscopico-percutaneo.

Bilio-pancreatic (BPD) tumours are pathologies with an overall resectability rate of 20-25%, with a high percentage of patients directed towards palliative treatment (70-90%). One hundred and twenty-eight patients underwent palliative treatment for BPD tumours. The M:F ratio was 1:1.5 and the mean age 61 years. The tumours were topographically divided into: 84 (63%) localised in the pancreatic head region; 34 (25%) biliary duct tumours and 6 arising in the ampulla of Vater. 42 patients (30%) underwent palliative surgical treatment (group 1) and 86 (70%) received non-surgical treatment (endoscopic percutaneous) (group 2). We also performed 6 gastrointestinal by-passes (GEA). The early morbidity rate was 36% in the first group and 12.8% in the second. The incidence of late morbidity in the first group was nil, with a mean survival of 10 months. Mortality was nil in both groups. Surgical by-pass is advisable in the presence of patients with a longer life expectancy and in good clinical condition but presents a high rate of early morbidity and a low percentage of late complications. The authors conclude that validity of the methods is similar. They believe that, in selected cases, surgical treatment remains the therapy of choice for BPD tumours.

[Sensitivity and specificity of transrectal ultrasonography in the preoperative staging and postoperative follow-up in rectal neoplasms. Experience with 100 clinical cases]. / Sensibilità e specificità dell'ultrasonografia trans-rettale nello staging preoperatorio e nel follow-up post-chirurgico delle neoplasie del retto. Esperienza su 100 casi clinici.

UNLABELLED: Preoperative staging plays an important role in the surgical treatment of rectal cancer. The most sensitive imaging techniques currently available are CT, MRI and transanal ultrasound (TAUS). The aim of the study was to evaluate the sensitivity and specificity of TAUS in the preoperative staging and postoperative follow-up of rectal cancer. METHODS: From January 1992 to May 1999, TAUS was used to study 100 patients with rectal cancer. RESULTS: Patients were staged according to the Astler-Coller classification: 1) A: 8 patients; 2) B1: 16 patients; 3) B2: 22 patients; C1: 30 patients; C2: 24 patients. The sensitivity and specificity of TAUS in the preoperative staging of these tumors were 96% for the T parameter, and 100% for the N parameter. The N but not the T parameter results are in line with the values reported in the international literature. CONCLUSION: Transanal ultrasound, in our personal experience, has proved to be a very accurate imaging technique in the preoperative staging and postoperative follow-up of rectal cancer.

[Short- and long-term monitoring with high-resolution ultrasonography of postoperative thyroid residue. Personal experience with 200 thyroidectomies]. / Monitoraggio a breve e lungo termine mediante ultrasonografia ad elevata risoluzione (us-hr) del residuo tiroideo post-operatorio Esperienza personale su 200 tiroidectomie.

BACKGROUND: After having abandoned conservative operations of the thyroid (partial resection, enucleal resection) today total thyroidectomy and sub-total thyroidectomy and near total thyroidectomy are the operations of choice. Cause the frequent post-operative scintigraphic signs, on the 3rd month, of thyroidal residue of significative size, founded in our patients operated for sub-total thyroidectomy, we begun to study the echografical monitoring of the thyroidal recess. METHODS: From January 1995 to December 1997 we operated 200 patients for Thyroidectomy. The kinds of operations were: total thyroidectomy for 96 patients (48%), sub-total thyroidectomy for 64 patients (32%), and near total thyroidectomy for 40 patients (20%). We controlled all the patients by ecografical monitoring of the thyroidal recess to detect and to determinate the possible thyroidal residue, that it will be monitorized on the 7th day, on the 1st month, on the 6th month and on the 12th month. We measured the thyroidal residual dimensions and volume. We recorded all the examinations by VCR or film and after we elaborated the results by exponential graphics. The patients that showed the thyroidal residues underwent to a scintigraphy. RESULTS: The thyroidal residuals were measured within the 7Th post-operative day. In the following controls we have noted a thyroidal residue hypertrophy. Multinodular goither was the disease with the highest degree of growth (until the 200% of the first measure of the residue). After an initial phase of growth almost all the patients showed a trend to the stabilization, with the exception only of the patient that suffered from multinodular goither. The scintigraphic examination was not realiable, in our experience, about the mathematic measurement of the thyroidal tissue, showing always an overvaluation of the residue. The best specificity was showed by US-HR. CONCLUSIONS: The patient that undergoes to total thyroidectomy needs an adequate suppressive and substitutive therapy. We identify the presence of several stimulating factors the growth of the residual thyroidal tissue that could arise to promote the hyperplasia and the hypertrophy of the parenchyma (EGF, TSG, TSI, PG). There are factors that are unidentified and are not subject to the suppression caused by substitutive therapy.

[Periampullar tumors: role of intraoperative color-Doppler ultrasonography in the evaluation of vascular invasion. Methods available to the surgeon and personal experience]. / I tumori della regione periampollare: ruolo della ultrasonografia color-doppler intraoperatoria nella valutazione della invasione vascolare. Metodiche a disposizione del chirurgo ed esperienza personale.

BACKGROUND: Tumors of the head of the pancreas and of the periampullary region, similar nosologic entity, represent the fourth most common cause of cancer death. These tumors are characterized bt high mortality rate associated with a low percentage of surgical resectability. Vascularly involvement is, in our experience, one of the criteria of exclusion for curative surgical resection. For this reason regional pancreasectomy don't show, in several case records, comforting datas about survival. METHODS: From 1995 to 1998 we introduced in the operative practice the color--doppler ultrasonography to diagnose vasculary involvement. We evaluated twenty patients that previously were candidated for surgical therapy consisting in a duodenal-pancreasectomy. All the patients were staged by preoperative abdominal ultrasound, E.R.C.P., CT, and angio M.R.I.. In no one of these patients were founded signs of vascularly involvement. We recognized by intraoperative color-doppler ultrasound three microscopic invasions of spleno-mesenteric-portal vasculary axis. RESULTS: U.S. I.O. C.D. in our case reports has underlined a sensibility and specificity of 100%. It has discovered, also, a false positive for neoplastic thrombosis, and a case of false negative. CONCLUSIONS: Intraoperative ultrasound shows a high sensibility about the intraoperative staging for the bibliopancreatic tumors. The study about the possible vascularly involvement is helped by the application of the colour in terms of an high sensibility and diagnostic care.

[Minimally invasive percutaneous ultrasonography-guided treatment of postoperative splenic abscess. Personal experience with 5 clinical cases]. / Terapia mininvasiva percutanea ultrasonoguidata degli ascessi post-chirurgici della milza. Esperienza personale su cinque casi clinici.

INTRODUCTION: Splenic abscesses are very rare pathologies encountered in daily clinical practice. The treatment, after failure of other medical treatments, has basically been surgical, in spite of large diffusion of percutaneous echo and CT techniques. The initial hesitation in applying this sort of method was caused by an unfounded fear of difficult management of haemorrhagic complications. METHODS: In our Clinic we treated 6 postoperative abscesses, observed in 5 patients. One of these (16%) was double and 3 concomitant with other intraperitoneal abscessual septic collections, which received priority in percutaneous treatment. In four cases (67%), Van-Sonnemberg drainage catheters were placed which caliber varied from 12 to 14 F. In the remaining two cases, we evacuated the abscess using an echo-guided needle puncture. In two cases we applied fibrinic glue; in one case as a haemostatic agent and in the other, to protect the wide abscessual cavity. RESULTS: We recorded the resolution of the symptomatology and instrumental findings in all patients. One patient died two weeks later due to unrelated causes. We recorded one minor complication which involved an intra-abscessual haemorrhage, which was then treated by fibrinic glue (Tissucol). CONCLUSION: Echo-guided percutaneous treatment, at present, is the treatment of choice for both multiple or single splenic abscesses. This treatment is not used for the miliaric form because we believe that in this case, the most appropriate choice is intensive medical treatment, which if fails, may require splenectomy.

[Carcinomas of the digestive system in patients under 20 years old]. / I carcinomi dell'apparato digerente in pazienti di età inferiore a 20 anni.

Gastrointestinal cancers are very scarce for the people under twenties. Such a rarity, as misguides diagnostic trend, is responsible, in the greater part of cases, of the lag in the recognizing these neoplasm and, consequently, reduces the expectations of surviving whether medium or long term. Authors report their experience as regards to observation of two cases of malignant neoplasm of the stomach and of the recto-sigmoid joint in young patients of fourteen and nineteen years old and they emphasize the importance of a complete diagnostic route which, in spite of age, does not exclude the possibility of a neoplastic pathology in the presence of suggestive persistent symptomatology. It is underlined the importance of early diagnosis in fact survival yield is always and however dependent on a disease stage and not on age. Furthermore it is underlined that the young patient is subject to a rate of postoperative complications which is marginal compared with intervention yield, this is translated in a better responsiveness of young patient to radical and, if it is necessary, extended interventions.

[Indications and technic for autotransfusion in surgery]. / Indicazioni e tecnica dell'autotransfusione in chirurgia.

The authors, after considering the advantages of autotransfusion, report their experience about 14 election patients operated on, and emphasize the usefulness of the usefulness of the method, designed to remove the iatrogenous pathology involved in the transfusions of homologous blood.

[Aneurysm of the superficial femoral artery]. / Aneurisma dell'arteria femorale superficiale.

The authors start from a case of aneurysm of the superficial femoral artery, they had the opportunity to observe, and discuss the etiopathogenetic, diagnostic and clinical problems involved in this disease. Then, they dwell upon the main therapeutical solutions suggested, and declare inclined to endoaneurysmography with interposition of autologous or heterologous grafting.

[Intentional normovolemic hemodilution (preliminary results)]. / L'emodiluizione normovolemica intenzionale (risultati preliminari).

The authors, after illustrating the advantages of hemodilution from the rheological, hemodynamic and district microcirculatory standpoint, illustrate their experience about 11 patients treated with such method. They point out the advantages this method can bring in both reducing the iatrogenous pathology involved in the hemodilution and reducing the difficulties faced by blood-banks and the costs burdening on the medical services.