177,121 research outputs found
Machine learning for the identification of decision boundaries during the transition from radial to vertical growth phase superficial spreading melanomas
No full textThe objective of this study was to compute threshold values for the diameter of superficial spreading melanomas (SSMs) at which the radial growth phase (RGP) evolves into an invasive vertical growth phase (VGP). We examined reports from 1995 to 2019 of 834 primary SSMs. All the patients underwent complete surgical removal of the tumor and the diagnosis was confirmed after histologic examination. Machine learning was used to compute the thresholds. For invasive non-naevus-associated SSMs, a threshold for the diameter was found at 13.2 mm (n = 634). For the lower limb (n = 209) the threshold was at 9.8 mm, whereas for the upper limb (n = 117) at 14.1 mm. For the back (n = 106) and the trunk (n = 173), the threshold was at 16.2 mm and 17.1 mm, respectively. When considering non-naevus-associated and naevus-associated SSMs together (n = 834) a threshold for the diameter was found at 16.8 mm. For the lower limb (n = 248) the threshold was at 11.7 mm, whereas for the upper limb (n = 146) at 16.4 mm. For the back (n = 170) and the trunk (n = 236), the threshold was at 18.6 mm and 14.1 mm, respectively. Thresholds for various anatomic locations and for each gender were defined. They were based on the diameter of the melanoma and computed to suggest a transition from RGP to VGP. The transition from a radial to a more invasive vertical phase is detected by an increase of tumor size with a numeric cutoff. Besides the anamnestic, clinical and dermatoscopic findings, our proposed approach may have practical relevance in vivo during clinical presurgical inspections
A new pericardium vascular prosthesis: Mechanical behavior, SEM analyses and clinical indications
No full textThis study deals with the mechanical characterization of a new vascular prosthesis. The prosthesis, made from a single portion of pericardial tissue, is bifurcated, crimped and not porous. The clinical use of this graft could increase hemocompatibility of the device compared to polymeric grafts and reduce the compliance mismatch between the natural vessel and the graft. Several mechanical analyses were performed to evaluate the load-displacement and the cyclic loading characteristics of the graft. Scanning electron microscopy was used to evaluate the tissue and suture line morphology before and after mechanical failure. The preliminary results of some clinical cases are also reported. The results point out that the prostheses, developed using correct technological procedures, show a mechanical behavior similar to that of natural arteries and could be successfully used in selected patients
Great saphenous vein versus expanded polytetrafluoroethylene graft in patients undergoing elective treatment of popliteal artery aneurysm with a posterior approach
No full textBackground: The aim of this study was to compare 30-day and 5-year outcomes of great saphenous vein (GSV) vs expanded polytetrafluoroethylene (ePTFE) graft in patients undergoing elective treatment of popliteal artery aneurysm (PAA) using a posterior approach. Methods: Between January 2010 and December 2023, a retrospectively maintained dataset of all consecutive asymptomatic PAAs who underwent open repair with posterior approach or endovascular repair in 40 centers was investigated. Of 971 cases, 525 patients were included in the present analysis. These were further divided into posterior approach with GSV graft (252; GSV group), and posterior approach with ePTFE graft (273; ePTFE group). Thirty-day outcomes were assessed and compared. During follow-up, survival, primary patency, secondary patency, freedom from reintervention(s), and amputation-free survival rates were compared between the two groups using log-rank tests. Univariate and multivariate Cox regression analyses were performed in the ePTFE group to find predictive factors of poor outcomes. Results: Two groups were homogeneous in terms of preoperative risk factors and morphological data. Median follow-up duration was similar (24 months [interquartile range [IQR], 10-36 months] GSV group vs 21 months [IQR, 7-47 months] ePTFE group; P =.123). At 5 years, there were no differences between the two groups in terms of survival (84.7% GSV group vs 86.1% ePTFE group; P =.097, log-rank = 2.756), secondary patency (94.9% GSV group vs 89.4% ePTFE group; P =.068, log-rank = 3.336), or amputation-free survival (99.1% GSV group vs 99.6% ePTFE group; P =.567, log-rank =.328). Five-year primary patency (89.5% GSV group vs 76.2% ePTFE group; P =.007, log-rank = 7.239) and freedom from reintervention(s) (92.8% GSV group vs 80.6% ePTFE group; P =.011, log-rank = 6.449) were significantly higher in the GSV group. Using multivariate analysis in the ePTFE group, factors compromising primary patency were patients on dialysis (P =.054; odds ratio, 3.641), and patients who were not on any preoperative antiplatelet therapy or anticoagulation (P =.019; odds ratio, 5.532), whereas none of the perioperative factors affected freedom from reintervention(s). Conclusions: GSV as graft guaranteed better primary patency with lower reinterventions rates at midterm follow-up after treatment of PAAs via a posterior approach. Patients on dialysis and who were not on any preoperative antiplatelet therapy or anticoagulation had lower patency rates
Acute medullary ischemia as clinical presentation of an intact infrarenal abdominal aortic aneurysm
No full textAbdominal aortic aneurysms (AAAs) are usually asymptomatic. Abdominal and/or low back pain are signs of rupture or impending rupture. We report the case of an 88-year-old man with unusual symptoms of clinical presentation for an AAA. He was admitted to our hospital with low back pain associated with bilateral lower extremity paresis. Examination revealed an abdominal pulsatile mass, and palpable peripheral pulses. Computed tomography angiography detected a 65-mm intact infrarenal AAA with neither signs of fissure or rupture nor lower extremity arterial disease. Magnetic resonance imaging demonstrated low-intensity signals at L1-L2 in the middle of the conus medullaris (acute medullary ischemia). The patient was managed conservatively with monoantiplatelet therapy, and low-weight-molecular heparin. Symptoms were resolved completely after 3 days. The final decision was to not treat the AAA
Le questioni pendenti: Le endoprotesi aortiche. La situazione nazionale: risultati di una indagine condotta presso i centri italiani che impiantano endoprotesi per il trattamento degli aneurismi dell'aorta addominale. Contributo in Bollettino di Chirurgia Endovascolare
No full textA new pericardium vascular prosthesis: mechanical behaviour, SEM analyses and clinical indications
No full textLow-fidelity simulators for the training of medical students in basic endovascular skills
No full textLetter to the edito
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