Five-year outcomes of fenestrated and branched endovascular repair of complex aortic aneurysms based on aneurysm extent.

OBJECTIVE: The aim of this study was to evaluate the 5-year outcomes of fenestrated/branched endovascular aortic repair (F/BEVAR) for the treatment of complex aortic aneurysms stratified by the aneurysm extent. METHODS: Patients with the diagnosis of complex aortic aneurysm, who underwent F/BEVAR at a single center were included in this study and retrospectively analyzed. The cohort was divided according to the aneurysm extent, comparing group 1 (types I-III thoracoabdominal aneurysms [TAAAs]), group 2 (type IV TAAAs), and group 3 (juxtarenal [JRAAs], pararenal [PRAAs], or paravisceral [PVAAs] aortic aneurysms). The primary endpoints were 30-day and 5-year survival. The secondary endpoints were technical success, occurrence of spinal cord ischemia, primary patency of the visceral arteries, freedom from target vessel instability, and secondary interventions. RESULTS: Of 436 patients who underwent F/BEVAR between July 2012 and May 2023, 131 presented with types I to III TAAAs, 69 with type IV TAAAs, and 236 with JRAAs, PRAAs, or PVAAs. All cases were treated under a physician-sponsored investigational device exemption protocol with a patient-specific company-manufactured or off-the-shelf device. Group 1 had significantly younger patients than group 2 or 3 respectively (69.6 ± 8.7 vs 72.4 ± 7.1 vs 73.2 ± 7.3 years; P < .001) and had a higher percentage of females (50.4% vs 21.7% vs 17.8%; P < .001). Prior history of aortic dissection was significantly more common among patients in group 1 (26% vs 1.4% vs 0.9%; P < .001), and mean aneurysm diameter was larger in group 1 (64.5 vs 60.7 vs 63.2 mm; P = .033). Comorbidities were similar between groups, except for coronary artery disease (P < .001) and tobacco use (P = .003), which were less prevalent in group 1. Technical success was similar in the three groups (98.5% vs 98.6% vs 98.7%; P > .99). The 30-day mortality was 4.5%, 1.4%, and 0.4%, in groups 1, 2, and 3, respectively, and was significantly higher in group 1 when compared with group 3 (P = .01). The incidence of spinal cord ischemia was significantly higher in group 1 compared with group 3 (5.3% vs 4.3% vs 0.4%; P = .004). The 5-year survival was significantly higher in group 3 when compared with group 1 (P = .01). Freedom from secondary intervention was significantly higher in group 3 when compared with group 1 (P = .003). At 5 years, there was no significant difference in freedom from target vessel instability between groups or primary patency in the 1652 target vessels examined. CONCLUSIONS: Larger aneurysm extent was associated with lower 5-year survival, higher 30-day mortality, incidence of secondary interventions, and spinal cord ischemia. The prevalence of secondary interventions in all groups makes meticulous follow-up paramount in patients with complex aortic aneurysm treated with F/BEVAR.

Effect of fenestration configuration on renal artery outcomes during fenestrated-branched endovascular aortic repair.

OBJECTIVE: The aim of this study was to evaluate the effect of fenestration configuration and fenestration gap on renal artery outcomes during fenestrated-branched endovascular aortic repair (F/BEVAR). METHODS: A retrospective multicenter analysis was performed, including patients with complex aortic aneurysms treated with F/BEVAR that incorporated at least one small fenestration to a renal artery. The renal fenestrations were divided into groups 1 (8 × 6 mm) and 2 (6 × 6 mm). Primary patency, target vessel instability (TVI), freedom from secondary interventions (SIs), occurrence of type IIIc endoleak, all related to the renal arteries, were analyzed at 30-day, 1-year, and 5-year landmarks. The fenestration gap (FG) distance was analyzed as a modifier, and clustering was addressed at the patient level. RESULTS: A total of 796 patients were included in this study, 71.7% male, with a mean age of 73.3 ± 8.1 years. The mean follow-up was 30.0 ± 20.6 months. Of the 1474 small renal fenestrations analyzed, 47.6% were 8 × 6 mm, and 52.4% were 6 × 6 mm. At the 30-day landmark, primary patency (99.9% vs 98.0%; P value < .001 for groups 1 and 2, respectively), freedom from TVI (99.6% vs 97.1%; P value < .001 for groups 1 and 2, respectively), and freedom from SI (99.8% vs 98.4%; P value = .022 for groups 1 and 2, respectively) were higher in 8 × 6 compared with 6 × 6 fenestrations, and the incidence of acute kidney injury was similar across the groups (92.6% vs 92.7%; P value = .953 for groups 1 and 2 respectively). The primary patency at 1 and 5 years was higher in 8 × 6 fenestrations (1-year: 98.8% vs 96.9%; 5-year: 97.8% vs 95.7%, for groups 1 and 2, respectively, P values = .010 and .021 for 1 and 5 year comparisons, respectively). The freedom from SIs was significantly higher among 6 × 6 fenestrations at 5 years (93.1% vs 96.4%, for groups 1 and 2, respectively, P value = .007). The groups were equally as likely to experience a type Ic endoleak (1.3% and 1.6% for 8 × 6 and 6 × 6mm fenestrations, respectively, P = .689). The 6 × 6 fenestrations were associated with higher risk of kidney function deterioration (17.8%) when compared with 8 × 6 fenestrations (7.6%) at 5 years (P < .001). The risk of type IIIc endoleak was significantly higher among 8 × 6 fenestrations at 5 years (4.9% and 2% for 8 × 6 and 6 × 6 mm fenestrations, respectively; P = .005). A FG ≥5 mm negatively impacted the cumulative 5-year freedom from TVI (group 1: FG ≥5 mm = 0.714, FG <5 mm = 0.857; P < .001; group 2: FG ≥5 mm = 0.761, FG <5 mm = 0.929; P < .001) and the cumulative 5-year freedom from type IIIc endoleak (group 1: FG ≥5 mm = 0.759, FG <5 mm = 0.921; P = .034; group 2: FG ≥5 mm = 0.853, FG <5 mm = 0.979; P < .001) in both groups and the cumulative 5-year patency in group 2 (group 1: FG ≥5 mm = 0.963, FG <5 mm = 0.948; P = .572; group 2: FG ≥5 mm = 0.905, FG <5 mm = 0.938; P = .036). CONCLUSIONS: Fenestration configuration for the renal arteries impacts outcomes. The 8 × 6 small fenestrations have better patency at 30 days, 1 year, and 5 years, whereas 6 × 6 small fenestrations are associated with lower rates of SIs, primarily due to a lower incidence of type IIIc endoleaks. FG ≥5 mm at the level of the renal arteries significantly impacts the freedom from TVI, freedom from type IIIc endoleak, and 5-year patency independently of the fenestration size or vessel diameter.

Outcome Analysis Comparing Asymptomatic Juxtarenal Aortic Aneurysms Treated with Custom-Manufactured Fenestrated-Branched Devices and the "Off-The-Shelf" Zenith p-Branch Device.

BACKGROUND: Numerous endovascular options have been used for the repair of juxtarenal aortic aneurysms (JRAAs) over the last 15 years. This study aims to compare the performance between the Zenith p-branch device and custom-manufactured fenestrated-branched devices (CMD) for the treatment of asymptomatic JRAA. METHODS: A single-center retrospective analysis of prospectively collected data was performed. Patients with a diagnosis of JRAA submitted to endovascular repair between July 2012 and November 2021 were included in the study, being divided into 2 groups: CMD and Zenith p-branch. The following variables were analyzed: preoperative information: demographics, comorbidities, and maximum aneurysm diameter; procedural data: contrast volume, fluoroscopy time, radiation dose, estimated blood loss, and technical success; and postoperative data: 30-day mortality, duration of intensive care unit and hospital stay, major adverse events, secondary interventions, target vessel instability, and long-term survival. RESULTS: From a total of 373 physician-sponsored investigational device exemption (Cook Medical devices) cases performed at our institution, 102 patients presented the diagnosis of JRAA. Of these, 14 patients were treated with the p-branch device (13.7%) and 88 (86.3%) with a CMD. Both groups presented similar demographic composition and maximum aneurysm diameter. All devices were successfully deployed, with no type I or III endoleaks observed at procedure completion. The contrast volume (P = 0.023) and radiation dose (P = 0.001) were significantly higher in the p-branch group. No significant difference was observed between the groups for the remaining intraoperative data. No paraplegia or ischemic colitis has been observed during the first 30 days after the surgical procedures. There was no 30-day mortality in either group. One major cardiac adverse event was registered in the CMD group. Early outcomes were similar in both groups. No significant difference was found between the groups with respect to the presence of type I or III endoleaks during the follow-up. From a total of 313 target vessels stented in the CMD group (mean of 3.55 per patient) and 56 in the p-branch group (mean of 4 per patient), 4.79% and 5.35% presented instability, respectively, with no difference observed between the groups (P = 0.743). Secondary interventions were required in 36.4% of the CMD cases and 50% of the p-branch group, but this was not statistically different (P = 0.382). In the p-branch cohort, 2 of 7 reinterventions (28.5%) were target vessel-related and in the CMD group, 10 of 32 secondary interventions (31.2%) were target vessel-related. CONCLUSIONS: Comparable perioperative outcomes were obtained when appropriately selected patients were treated with either the off-the-shelf p-branch or CMD for JRAA. The long-term target vessel instability does not appear impacted by the presence of pivot fenestrations in comparison to other target vessel configurations. Given these outcomes, delay in CMD production time should be considered when treating patients with large juxtarenal aneurysms.

Biomechanical Analysis of Cadaveric Thoracic Aorta Zones: The Isthmus is the Weakest Region.

BACKGROUND: The thoracic aorta is a site of multiple pathological processes, such as aneurysms and dissections. When considering the development of endovascular devices, this vessel has been extensively manipulated because of aortic diseases, as well as to serve as a route for procedures involving the head and neck vessels. Therefore, the aim of the present study was to obtain biomechanical experimental information about the strength and deformability of this vessel. MATERIALS AND METHODS: Thirty-one thoracic aorta specimens were harvested during the autopsy procedure. They were carefully dissected and transversally sectioned according to Criado's aortic arch map landing zones (0 to 4). The supra-aortic trunks were removed, and the aortic rings were opened in their convexity, which resulted in flat tissue segments. Four millimeter-wide strips were prepared from each zone after which they were attached to a clip system connected to the INSTRON SPEC 2200 device, which was responsible for pulling the fragment up to its rupture during the uniaxial tension test. The INSPEC software was used to coordinate the test, and data management was conducted via the SERIES IX software. The biomechanical variables that were measured included failure stress, failure tension, and failure strain. RESULTS: When comparing the five segments from all 31 aortas, three different strength levels were observed. Zones 0 and 1 exhibited the highest failure stress and failure tension values, followed by Zones 2 and 4. Zone 3 (aortic isthmus) was the weakest segment that was tested when compared to the stress and tension of Zones 0 and 1 (P < 0.001), the stress and tension of Zone 2 (P = 0.005 and P = 0.002, respectively) and the stress and tension of Zone 4 (P = 0.023 and P = 0.006, respectively). Among donors > 65 years-old, women presented significantly weaker descending aortas than men in regards to stress (P = 0.049) and tension (P = 0.014). Among male donors, the elderly donors presented significantly stiffer aortic walls and weaker ascending (P = 0.029 for stress) and descending (P = 0.004 for stress; P = 0.031 for tension) aortas than younger men. CONCLUSIONS: Uniaxial tensile strength tests revealed that the thoracic aorta is a very heterogeneous vessel. Isthmus frailty may add to the understanding of the pathophysiology of some aortic diseases that commonly compromise this region. The lower strength that was verifiedin some aortic segments from elderly donors may contribute to the genesis of some thoracic aorta diseases among that group of donors. These data can contribute to the development of new endovascular devices that are specifically designed for this vessel.

Experimental Study of Rupture Pressure and Elasticity of Abdominal Aortic Aneurysms Found at Autopsy.

BACKGROUND: Resistance and elasticity of normal and aneurysmal aorta walls are directly associated with this vessel's growth and rupture. This study aims to experimentally analyze the biomechanical behavior of aneurysmal specimens found at autopsy, comparing them with normal diameter aortas removed from age-matched donors. METHODS: Thirty-eight human aortas (30 normal aortas; 8 infrarenal abdominal aortic aneurysms) were harvested during autopsy. An apparatus was built with a digital gauge, plastic tray, connections, and hoses that conducted fluid (air) from a pump through the system. Specimens were dissected, and a flexible balloon was introduced in each of them to avoid leakage. The specimens were fastened on the test tray, and activation of the air pump enhanced system pressure up to their rupture. RESULTS: All 8 aneurysms and all 30 normal aortas specimens evolved to rupture under inflation pressures above 590 mm Hg (mean ± standard deviation = 1,035 ± 375 mm Hg) and 840 mm Hg (mean ± SD = 1,405 ± 342 mm Hg), respectively. In the aneurysm group, 25% of specimens did not rupture in their most dilated region. Percentage of increment in diameter was higher in normal aortas (mean ± SD = 0.2106 ± 0.144) than in aneurysms (mean ± SD = 0.093 ± 0.070). CONCLUSIONS: In the present experiment, unruptured infrarenal abdominal aortic aneurysms could support high pressures nearly as much as nonaneurysmal abdominal aortas. In some specimens, the most dilated part of the aneurysm was not the most vulnerable under pressure. Normal aortas presented higher elasticity than aneurysms.

Biomechanical Properties of the Periaortic Abdominal Tissue: It is Not as Fragile as It Seems.

BACKGROUND: The perivascular adipose tissue has been studied as a critical element that could influence physiological and disease processes of the vessel covered by it. In terms of anatomy, during the abdominal aorta's dissection, it is possible to identify the periaortic adipose tissue and the periaortic parietal peritoneum lying over it, sealing the retroperitoneal space. They seem to be fragile layers, with apparently no biomechanical role in the abdomen. However, it is well known that most cases of ruptured abdominal aortic aneurysms (AAAs) that reach the emergency department still alive present retroperitoneal bleeding contained by the previously mentioned two-layer combination, eventually allowing time for surgical treatment. In previous studies about aortic wall stress, tension, and AAA rupture prediction, only information concerning the vessel wall itself is highlighted. Therefore, the present work aims to study the biomechanical and histological properties of the periaortic tissue, comparing them to the same variables measured in aortic wall samples described in the medical literature. MATERIALS AND METHODS: Samples of periaortic tissue were harvested from 27 individuals during necropsy. Smoking status and the presence of AAAs were observed. Biomechanical uniaxial destructive tests were performed up to samples' rupture. Values of failure stress, tension, and strain were obtained. Samples were also harvested for histological analysis. RESULTS: Periaortic tissue presented less amount of collagen in smokers than in nonsmokers (P = 0.017). The periaortic tissue seems to be more elastic than aortic walls described in the literature (strain: 0.75 ± 0.37). Analyzing periaortic tissue failure stress (56.8 ± 101.26 N/cm2) and tension (7.65 ± 4.99 N/cm), it has at least 52% and 55%, respectively, of the stress and tension described in the medical literature for AAA walls. CONCLUSIONS: The periaortic tissue presents less collagen fibers in smokers than in nonsmokers. The periaortic tissue seemed very delicate during an autopsy, but the study of its biomechanical properties showed that it presents more than half of the resistance of an AAA wall. This information suggests this tissue might have a mechanical protective role against massive bleeding when it comes to an aortic rupture. Therefore this tissue's biomechanical information should be included in computational models on enlargement and rupture prediction of AAAs.

Left Common Carotid Artery Biomechanical Properties in Individuals over 80 years: Women Have Stiffer Vessels.

BACKGROUND: Considering the longevity of the worldwide population, the cardiovascular diseases deserve particular attention, especially the carotid artery disease in the ≥80-year-old population. The stiffness of the common carotid artery, for example, has been showed in numerous clinical studies as a marker of increased risk of stroke, dementia, and depression. Besides, with the emergence of new surgical techniques such as the transcarotid artery revascularization that uses the common carotid artery as a workstation, the biomechanical and histological features of this vessel, more than ever, must be detailed. METHODS: Left common carotid artery fragments from 9 cadaver donors (≥80 years old) were evaluated. Biomechanical (failure stress, tension, and strain) and histological (percentage of collagen and elastic fibers) features of these samples were analyzed with special focus on gender differences. RESULTS: Statistically significant differences in biomechanical and histological features between the genders were observed. The percentage of collagen fiber in intima (P = 0.008) and media (P = 0.041) layers was significantly lower in men than in women. A higher elasticity (failure strain) of the specimens in male gender was also observed (P = 0.025). No significant difference was observed in the layers thickness between the genders regardless which part of the arterial wall was considered. CONCLUSIONS: These biomechanical and histological findings could be the responsible for the higher left common carotid artery stiffness observed among ≥80-year-old women when compared with men in numerous clinical studies in literature.

Case Series on Double-Barrel Stenting for the Renal Arteries Associated With Fenestrated Repair (FEVAR) of Complex Anatomy Aortic Aneurysms.

The double-barrel stenting (DBS) is a technique in which 2 parallel stents are simultaneously deployed through the same reinforced fenestration, into 2 adjacent target vessels. Prior reports describe the application of this technique for the treatment of superior mesenteric artery dissection with aneurysmal degeneration, coronary artery bifurcations, aortic arch branches, and intracranial aneurysms. The DBS technique is particularly useful in the context of fenestrated repair (FEVAR) of complex anatomy aortic aneurysms when the origin of visceral arteries branch off the aorta very close to each other or present early branches. We herein describe a case series including 7 patients who underwent a FEVAR procedure for thoracoabdominal and juxtarenal aortic aneurysms in which the presence of accessory renal arteries (ARA) or early renal branches was the reason for the application of this technique. Technical success was 100% and all stents were patent in the last follow-up CT scan (follow-up range: 1.8-62.8 months). There was only 1 small endoleak from indetermined source potentially related to the DBS, but the aneurysm sac decreased in size during follow-up and no secondary intervention was needed. Therefore, the DBS technique is a viable option for the incorporation of ARA or early renal branches to a fenestrated repair of aortic aneurysms with complex anatomy.

Rare Case of Abdominal Aortic and Multiple Visceral Aneurysms in a Pediatric Patient With PIK3CA Mutation and Vasculitis.

Abdominal aortic aneurysms (AAA) are most commonly observed in elderly male patients and are particularly rare in children. Among the pediatric population, they are usually diagnosed in the context of connective tissue disorders, genetic mutations, or vasculitis. The same is true of visceral arteries aneurysms. This case report describes the staged management of an 11-year-old patient presenting PIK3CA mutation and a 5.8 cm infrarenal AAA associated with bilateral common iliac arteries and multiple visceral aneurysms, the largest observed in the superior mesenteric artery (SMA = 3.2 cm). After careful evaluation, decision was made to first approach the most life-threatening lesion (the infrarenal AAA due to the large diameter) and the remaining aneurysms in secondary procedures, with special attention to the SMA aneurysm. The patient underwent a staged repair, with the first phase consisting of an aortobi-iliac graft with the distal anastomosis made at the left common iliac artery and right external iliac artery. The right hypogastric artery was ligated. The second procedure consisted of SMA aneurysm repair with a plication technique, as 7 branches were visualized coming off the aneurysm sac. Postoperative pathology analysis of the aortic and SMA aneurysms sac revealed vasculitis with a mixed inflammatory pattern and a COL3A1 gene heterozygote variant. He is currently in his 18th month after the last surgical intervention, receiving immunomodulatory therapy, with a planned follow-up by the interdisciplinary team to monitor the medications' side effects and the diameter of the remaining visceral aneurysms.

Biomechanical and histological data from abdominal aortas harvested in autopsy.

This data article describes biomechanical and histological information of abdominal aortas harvested in autopsy. Eight abdominal aorta aneurysms (AAA) and 30 normal diameter abdominal aortas were collected and submitted to an inflation test up to their rupture. This inflation procedure was part of the research entitled "Experimental study of rupture pressure and elasticity of abdominal aortic aneurysms found at autopsy", submitted to Annals of Vascular Surgery. The rupture borders and control samples (harvested from places other than the rupture site) were submitted to uniaxial destructive tensile test and to histological analysis. The following variables were evaluated in the biomechanical test: failure stress, failure tension and failure strain. The histological processing of the samples enabled a quantitative analysis of the percentage of coverage of collagen fibers and elastic fibers in the samples. The present data could be reutilized because they are experimental evidence that cadaveric abdominal aortas, even when previously stressed by inflation, conserve significant resistance against tearing comparable to no previously stressed aortas described in the literature. Considering real whole cadaveric AAAs are especially scarce, this information would be a useful reference source for further in-depth research in the aortic biomechanics field.

Biomechanics data of human supra-aortic trunks and abdominal visceral arteries harvested during autopsy.

The present dataset describes the biomechanical properties of the supra-aortic trunks (brachiocephalic trunk, left common carotid artery, and left subclavian artery) and some of the visceral branches of the abdominal aorta (celiac trunk, superior mesenteric artery, and renal arteries). The specimens have been harvested from 27 adult donors during the autopsy procedure. The vessels were submitted to uniaxial biomechanical tensile tests, and values of failure stress, failure tension, and failure strain were obtained. As atherosclerosis could affect any of those vessels producing a significant reduction in their lumen, the data presented here could be of great interest to vascular surgeons, interventional cardiologists, and interventional neuroradiologists, who manipulate these arteries endovascularly. The observations gathered here are experimental evidence of the vessels' endurance against tearing and of their deformability. Therefore this data article could also help the medical industry dedicated to the production of endovascular devices. This dataset is related to the article entitled "Left Common Carotid Artery Biomechanical Properties in Individuals over 80 years: Women Have Stiffer Vessels" published in Annals of Vascular Surgery in August 2020 [1].

[Occult metastasis in sentinel lymph node in early-stage breast cancer]. / Metástase oculta em linfonodo sentinela no câncer de mama em estádios iniciais.

PURPOSE: sentinel lymph node biopsy in early-stage breast cancer patients has been substituting the total axillary lymph node is presented dissection. The technique of processing the sentinel lymph node and the aim of this study was to investigate the efficacy of occult metastasis identification based on the standard histological and immunohistochemical examination. METHODS: between 2002 and 2005, 266 sentinel lymph nodes were harvested from axillary biopsy of 170 patients with early stage breast cancer. All lymph nodes were considered to be negative according to standard intra-operative cytological assessment. Lymph nodes were transversally sectioned in four or five slices and embedded in paraffin blocks. Two paraffin-embedded tissue sections with 4 microm in thickness were mounted on glass slides and stained with hematoxylin-eosin and immunoperoxidase (cytokeratin AE1/AE3) techniques. RESULTS: standard histological examination identified metastasis in 22 patients (12.9%) and micrometastatic disease was observed in six of these patients (3.5%). The immunohistochemical examination identified metastatic disease in 16 patients (9.4%). Among them, isolated tumor cells were observed in 11 (6.5%) and micrometastases were identified in five (2.9%). CONCLUSIONS: the association of the standard histological examination and immunohistochemical technique increases the chances of sentinel lymph node metastasis identification.

Metástase oculta em linfonodo sentinela no câncer de mama em estádios iniciais / Occult metastasis in sentinel lymph node in early-stage breast cancer

OBJETIVO: a identificação e biópsia do linfonodo sentinela (LS) no câncer de mama em estádio inicial vêm substituindo a dissecção axilar total. Neste estudo, será apresentada a técnica de processamento do LS, visando o diagnóstico de metástase oculta com base no exame histológico e imuno-histoquímico. MÉTODOS: entre os anos de 2002 e 2005, 266 linfonodos sentinelas foram dissecados em 170 pacientes com câncer de mama em estádio inicial. Foram incluídos apenas os linfonodos considerados negativos durante análise intra-operatória por citologia. Os linfonodos foram seccionados tranversalmente em quatro ou cinco fatias e incluídos em parafina. Em cada bloco de parafina, dois cortes histológicos com 4 µm de espessura foram montados em lâminas para microscopia de luz e corados pela técnica da hematoxilina-eosina e imunoperoxidase (citoqueratina AE1/AE3). RESULTADOS: a avaliação histológica convencional identificou metástase no LS de 22 pacientes (12,9 por cento). Em seis destas (3,5 por cento), o acometimento foi do tipo micrometástase. Já a metástase oculta diagnosticada exclusivamente pela imuno-histoquímica ocorreu em 16 pacientes (9,4 por cento). Em 11 destas (6,5 por cento) foram detectadas células tumorais isoladas e em cinco (2,9 por cento), micrometástases. CONCLUSÕES: a associação do exame histológico de parafina e imuno-histoquímica aumenta a capacidade de identificar metástase oculta no LS de pacientes com câncer de mama em estádios iniciais.

PURPOSE: sentinel lymph node biopsy in early-stage breast cancer patients has been substituting the total axillary lymph node is presented dissection. The technique of processing the sentinel lymph node and the aim of this study was to investigate the efficacy of occult metastasis identification based on the standard histological and immunohistochemical examination. METHODS: between 2002 and 2005, 266 sentinel lymph nodes were harvested from axillary biopsy of 170 patients with early stage breast cancer. All lymph nodes were considered to be negative according to standard intra-operative cytological assessment. Lymph nodes were transversally sectioned in four or five slices and embedded in paraffin blocks. Two paraffin-embedded tissue sections with 4 µm in thickness were mounted on glass slides and stained with hematoxylin-eosin and immunoperoxidase (cytokeratin AE1/AE3) techniques. RESULTS: standard histological examination identified metastasis in 22 patients (12.9 percent) and micrometastatic disease was observed in six of these patients (3.5 percent). The immunohistochemical examination identified metastatic disease in 16 patients (9.4 percent). Among them, isolated tumor cells were observed in 11 (6.5 percent) and micrometastases were identified in five (2.9 percent). CONCLUSIONS: the association of the standard histological examination and immunohistochemical technique increases the chances of sentinel lymph node metastasis identification.