ERASMO SIMAO DA SILVA
Projetos de Pesquisa
Unidades Organizacionais
Departamento de Cirurgia, Faculdade de Medicina - Docente
LIM/02 - Laboratório de Anatomia Médico-Cirúrgica, Hospital das Clínicas, Faculdade de Medicina - Líder
LIM/02 - Laboratório de Anatomia Médico-Cirúrgica, Hospital das Clínicas, Faculdade de Medicina - Líder
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- The Distensibility of the Human Vena Cava and Its Importance to In Vitro Studies of Venous Compression Syndromes: A Search for a Suitable Polymer for 3-Dimensional Printing(2023) PUECH-LEAO, Pedro; TORRES, Inez O.; SILVA, Erasmo S. da; CESTARI, Ismar N.; CESTARI, Idagene A.; ROSA, Jhenyfer M. da; NAHAS, William C.; LUCCIA, Nelson DeBackground: Venous compression syndromes are clinical conditions in which the large veins are compressed by other anatomical structures. Laboratory simulations may help us better understand the hemodynamics in venous compressions by creating situations similar to those seen in vivo. The aim of this study is to produce a model of the caval bifurcation using a polymer with distensibility similar to the human vena cava. Methods: Fragments of the inferior vena cava were collected from 13 deceased kidney donors (aged 15-37 years) and were tested for deformation (strain) when subjected to distension at 50 N/cm2. Strips of 5 different polymers-thermic polyurethane and Agilus30 with Vero Magenta (AV) (in 3 different hardnesses) and silicone-were subjected to the same biomechanical tests and compared with the vena cava. A model of the caval bifurcation was produced with 3-D printing. Results: The deformation (strain) of the vena cava wall was 0.16 & PLUSMN; 0.9 when submitted to stress close to 50 N/cm2. Silicone showed a strain higher than the standard deviation of venous fragments. The strain of AV resin 95 Shore was lower than the standard deviation of the venous fragments. AV Resins 70 and 85 Shore showed strains within the standard deviation of the venous specimen, with 70 Shore being closest to the mean venous strain. Therefore, this material was selected for modeling the caval bifurcation. The computed tomography scan image generated a computer model of the caval bifurcation and was printed in 3 dimensions. In addition, the segments of 2 adjacent vertebrae were also printed to reference the compression site. Conclusions: The 3-D printing of large veins can produce models with anatomy and biome-chanics similar to those of human veins and opens a field of investigation into the hemody-namics of venous compression syndromes. Polymers with Shore A70 appear to have biomechanical properties similar to those of the vena cava wall. The model obtained in this study can be used in several in vitro studies of May-Thurner Syndrome.
- Aorta Rupture Assay: Comparing the Failure Pressure of Infrarenal Abdominal Aortic Aneurysm and Normal Abdominal Aorta Specimens(2019) GOMES, Vivian C.; RAGHAVAN, Madhavan L.; SILVA, Luiz F. da; ZYNGIER, Selene; SILVESTRE, Gina; QUEIROZ, Alexandre; MARQUES, Michele A.; SILVA, Erasmo S. da
- Percutaneous endovascular delivery of calcium chloride to the intact porcine carotid artery: A novel animal model of arterial calcification(2020) ABRAO, Sergio R.; CAMPOS, Carlos M.; CAVALCANTE, Rafael; EGGERMONT, Jeroen; LEMOS, Pedro; LEDERMAN, Alex; SILVA, Erasmo S. da; AUN, Ricardo; BELCZAK, Sergio Q.; ABIZAID, Alexandre; JR, Fabio Sandoli de BritoObjective The present study evaluated the effect of endovascular administration of calcium chloride to the carotid artery of swines, to create a model of arterial calcification. Methods Fifteen Large White pigs were used for the study. Via endovascular treatment, carotid arteries were exposed during 9 min to either calcium chloride (experimental artery) or saline (control artery) with the use of the TAPAS catheter. Intravascular ultrasound (IVUS) imaging was obtained at baseline, postprocedure and at 30 days. Optical coherence tomography (OCT) imaging was obtained in vitro after carotids were harvested. Longitudinally cut parallel arterial segments were placed in a system of delicate clamps and underwent uniaxial strain test. All arteries underwent histopathological examination. Results Calcium chloride treated segments showed extensive circumferential parietal calcification evident on both IVUS and OCT. Reduction in minimal lumen area on IVUS was evident in experimental arteries both at 24 hr and 30 days postprocedure. Histopathologic assessment (Von Kossa stain) confirmed medial calcification with mild intimal thickening. Biomechanical testing showed treated segments to have smaller breaking strength and less elastic deformation than controls. Conclusion We developed a nonexpensive, reproducible model of early carotid medial calcification in pigs. Our model has the potential to help the development of research to unravel mechanisms underlying arterial calcification, the use of current or new devices to treat calcified lesions as well as to serve as an option for training interventionalists on the use of such devices.
- The similarities and differences among patients with abdominal aortic aneurysms referred to a tertiary hospital and found at necropsy(2015) SILVA, Erasmo S. da; GORNATI, Vitor C.; CASELLA, Ivan B.; AUN, Ricardo; ESTENSSORO, Andre E. V.; PUECH-LEAO, Pedro; LUCCIA, Nelson DeObjective: To analyze the characteristics of patients with abdominal aortic aneurysms referred to a tertiary center and to compare with individuals with abdominal aortic aneurysm found at necropsy. Methods: We have retrospectively analyzed the medical records of 556 patients with abdominal aortic aneurysm and 102 cases abdominal aortic aneurysm found at necropsy. Results: At univariated analysis, hypertension, tobacco use and maximum diameter were significant risk factors for symptomatic aneurysm, while diabetes tended to be a protective factor for rupture. By logistic regression analysis, the largest transverse diameter was the only one significantly associated with abdominal aortic aneurysm rupture (p<.0001, odds ratio 1.7, 95% confidence interval 1.481-1.951). Intact abdominal aortic aneurysm found at necropsy showed similarities with outpatients in relation to abdominal aortic aneurysm diameter and risk factors. Conclusion: Intact abdominal aortic aneurysm at necropsy and at outpatients setting showed similarities that confirmed that abdominal aortic aneurysm repair is less offered to women, and they died more frequently with intact abdominal aortic aneurysm from other causes.
- Does elevated wall tension cause aortic aneurysm rupture? Investigation using a subject-specific heterogeneous model(2017) CHUNG, Timothy K.; SILVA, Erasmo S. da; RAGHAVAN, Suresh M. L.Objective: To investigate whether peak wall tension in abdominal aortic aneurysm occurs at the site of rupture to test for a causative relationship. Methods: Four ruptured and nine unruptured AAA were harvested whole from cadavers, followed by regional measurements of wall thickness, elastic parameters and failure tension. Finite element models were developed with subject-specific load-free AAA morphology and heterogeneous properties interpolated using a geodesic distance weighted approach from the measurements. The wall tension under uniform pressure and tension to failure tension ratio as an index of susceptibility to rupture were computed. As a secondary aim, the peak wall tension using this heterogeneous model approach was compared to the traditional homogeneous model approach in order to evaluate the reliability of the latter. Results: The average peak wall tension in the ruptured group was 43% higher than in the unruptured group without statistical significance even though it was 54% larger in diameter. The site of peak wall tension was in the vicinity of the site of rupture in two ruptured MA. The peak tension did not breach failure tension at the rupture site in any of the AAA. The traditional population-wide homogeneous model approach overestimated peak wall tension by just 3% compared to the subject-specific heterogeneous model approach. Conclusion: We failed to find adequate evidence of a causative relationship between peak wall tension and AAA rupture. The findings are not conclusive owing to study limitations such as ignoring intraluminal thrombus, sparse distribution of specimens procured and small study population.
- Catheter-directed foam sclerotherapy with tumescence of the great saphenous vein versus ultrasound-guided foam sclerotherapy: A randomized controlled trial(2020) SANTOS, Jorgete B. dos; CAMPOS JUNIOR, Walter; PORTA, Rina M. P.; PUGGINA, Juliana; SILVA, Daniela F. T. da; PUECH-LEAO, Pedro; LUCCIA, Nelson de; SILVA, Erasmo S. daObjectives To compare the effectiveness of two foam sclerotherapy techniques of the great saphenous vein. Methods Fifty subjects with varicose veins, edema, and great saphenous vein incompetence (diameter 6-10 mm) were randomly categorized into two equal groups and were treated with different foam sclerotherapy techniques: A (usual ultrasound-guided) and B (catheter-directed with tumescence). Concomitant phlebectomy was performed in all patients. Patients were seen on days 7 and 28, and at six and 12 months. The primary outcomes were the full success rate of the treated great saphenous vein and the number of patients who required retreatment sessions performed at 28-day follow-up. The secondary-assisted outcomes were the full success rates of the treated great saphenous vein after the retreatment sessions at six- and 12-month follow-up. Secondary outcomes were changes in quality of life and side effects and complications of the intervention. In case of reflux, retreatment sessions were performed at 28 days and six months in both groups. Results Full success rate of the treated great saphenous vein was 36% in group A vs. 80% in group B (p = 0.012) and the number of patients who required retreatment sessions were n = 14 in group A vs. n = 3 in group B at 28-day follow-up (p = 0.002). Both were statistically significant. At six and 12 months, the success rates were not statistically significant between the groups. Complication rates were similar between the groups. Quality of life improved in both groups with statistical difference (p < 0.001). Conclusions Catheter-directed foam sclerotherapy with tumescence was better than usual ultrasound-guided foam sclerotherapy as it reached higher full success rate of the treated great saphenous vein and as a lower number of patients required retreatment sessions in the short-term. Both methods proved to be safe and improved the quality of life.
- Plasma advanced glycation end products and soluble receptor for advanced glycation end products as indicators of sterol content in human carotid atherosclerotic plaques(2022) PINTO, Raphael S.; FERREIRA, Guilherme S.; SILVESTRE, Gina Camillo R.; SANTANA, Monique de Fatima M.; NUNES, Valeria S.; LEDESMA, Lucas; PINTO, Paula R.; ASSIS, Sayonara Ivana S. de; MACHADO, Ubiratan F.; SILVA, Erasmo S. da; PASSARELLI, MarisaAdvanced glycation end products (AGEs) are independently related to cardiovascular disease (CVD) and favor cholesterol and oxysterol accumulation in macrophage foam cells. Soluble RAGE (sRAGE) impairs cellular AGE signaling alleviating the deleterious effects of AGE in atherogenesis. The association between plasma AGEs and sRAGE with the content of cholesterol, markers of cholesterol synthesis and absorption, and oxysterols in atherosclerotic plaques was evaluated in subjects undergoing carotid endarterectomy. Plasma and carotid plaques were obtained from symptomatic (n = 23) and asymptomatic subjects (n = 40). Lipids from plaques were extracted and sterols (oxysterols, cholesterol, desmosterol, lathosterol, sitosterol, and campesterol) were determined by using gas chromatography/mass spectrometry. Plasma total AGEs and pentosidine were measured by using fluorimetry and sRAGE by using ELISA. In symptomatic subjects ' atherosclerotic plaques, an increased amount of cholesterol (3x) and oxysterols [7 alpha-hydroxycholesterol (1.4x); 7 beta-hydroxycholesterol (1.2x); 25-hydroxycholesterol (1.3x); 24-hydroxycholesterol (2.7x), and 27-hydroxycholesterol, (1.15x)], with exception to 7 ketocholesterol, were found in comparison to asymptomatic individuals. Plasma total AGEs and pentosidine significantly and positively correlated to sterols accumulated in the atherosclerotic lesion, including cholesterol, desmosterol, campesterol, sitosterol, and oxysterols. On the other hand, sRAGE inversely correlated to total AGEs and pentosidine in plasma, and with major species of oxysterols, cholesterol, and markers of cholesterol synthesis and absorption in the atherosclerotic lesion. In multiple regression analyses, it was observed a significant inverse correlation between sRAGE and 24-hydroxycholesterol and desmosterol, and a positive significant correlation between pentosidine and 24-hydroxycholesterol, 27-hydroxycholesterol, and campesterol. In conclusion, the plasma concentration of AGEs and sRAGE is a tool to predict the accumulation of sterols in atherosclerotic lesions in symptomatic and asymptomatic individuals, helping to prevent and improve the management of acute cardiovascular complications.
- Characterization and Natural History of Patients with Internal Carotid Occlusion: A Comparative Study(2018) MULATTI, Grace Carvajal; PUECH-LEAO, Pedro; LUCCIA, Nelson De; SILVA, Erasmo S. daBackground: To characterize patients with internal carotid occlusion (ICO) with respect to demographic data, associated diseases, medical management, and risk factors and to compare these patients with those with nonsignificant stenosis (NSS; less than 50% stenosis). Secondary end points were new neurologic events, progression of contralateral degree of stenosis, cardiovascular symptoms, and death during follow-up. Methods: Retrospective analysis was performed using data collected from clinical records and added to a prospective database. Missing data were obtained during phone interviews or requested medical appointments. Results: From 2005 to 2013, 213 patients with ICO and 172 with NSS were studied (medium follow-up 37.81 months). Among the patients with ICO, a greater proportion were men, had a history of smoking, and presented with peripheral arterial disease and a lower creatinine clearance compared with those with NSS (P < 0.05). At the time of diagnosis, 76.1% of the patients with ICO were symptomatic compared with 35.5% of those with NSS (P = 0.000001). The patients in the ICO group exhibited significant progression of contralateral stenosis compared with those in the control group with progression on any side (15.0% vs. 2.3%, P = 0.00011). In addition, 18 patients in the ICO group (8.5%) exhibited new neurological symptoms compared with 13 (7.6%) in the NSS group (P = 0.41). When the ICO and NSS groups were combined, 10.8% of the initially symptomatic patients presented with new symptoms compared with 4.3% of those who were initially asymptomatic (P = 0.0218). The number of deaths was significantly higher among the patients in the ICO group (14.1% vs. 6.4%, P = 0.0150). Conclusions: Patients presenting with ICO have more risk factors and higher mortality by any cause. Initially, symptomatic patients will likely present with more neurological symptoms during follow-up, independent of carotid morphology, ICO, or NSS. Efforts must be made to identify those at risk before occlusion and to prevent secondary events and death.