Ablation Of Vessels Research Articles

Radio-frequency ablation of umbilical vessels in complicated monochorionic twin gestations

Aims: Radio-frequency ablation provides a novel minimally-invasive percutaneous ultrasound-guided procedure for umbilical vessel closure in complicated discordant monochorionic twin gestations, TRAP and TTTS. The purpose of this abstract is to present outcome data of 15 cases.

W1119 Effective Ablation of Ecstatic Vessels Using Radiofrequency Energy Ablation for Bleeding from Chronic Radiation Proctitis As Imaged Using Endoscopic Optical Coherence Tomography

W1119 Effective Ablation of Ecstatic Vessels Using Radiofrequency Energy Ablation for Bleeding from Chronic Radiation Proctitis As Imaged Using Endoscopic Optical Coherence Tomography

Combining Surgical Ablation of Retinal Inflow and Outflow Vessels With Photodynamic Therapy for Retinal Angiomatous Proliferation

To evaluate short-term efficacy of combining surgical ablation of retinal inflow and outflow vessels and photodynamic therapy (PDT) for stage 3 retinal angiomatous proliferation (RAP). Prospective interventional case series. Five eyes (five patients) underwent surgical ablation of inflow and outflow vessels and PDT for stage 3 RAP. Inflow and outflow vessels were ablated in four eyes, and only inflow was ablated in one eye. In four eyes starting PDT within six weeks of surgical ablation, choroidal neovascularization (CNV) disappeared or shrank after one PDT session (three months follow-up). However, CNV enlarged again in three of the four (final follow-up) because of reperfusion from newly formed inflow vessels. In one eye starting PDT seven months after ablation, a new retinal inflow vessel feeding the CNV appeared by the time of the first PDT session. The CNV continued to expand, despite two PDT sessions. Combining surgical ablation and PDT was not useful on account of a high frequency of reperfusion from retinal inflow vessels.

Treatment Strategy to Optimize Radiofrequency Ablation for Liver Malignancies

The purposes of this study were to investigate a treatment strategy to increase liver tumor necrosis and minimize complications with ultrasound-guided percutaneous radiofrequency (RF) ablation and to evaluate its therapeutic efficacy. A total of 332 patients with 503 liver malignancies underwent RF ablation according to a mathematical protocol with adjunctive measures. In the 332 patients, 205 had 308 hepatocellular carcinomas (HCCs) with a mean largest diameter of 4.1 cm and 127 had 195 metastatic liver carcinomas (MLCs) with a mean largest diameter of 3.9 cm. In patients with HCC, 60 (29.3%) had stage I/II disease and 145 (70.7%) had stage III/IV disease. Depending on tumor size, shape, and location, a defined treatment strategy was adopted that consisted of a mathematical protocol, an individualized protocol, and adjunctive measures. The mathematical protocol was followed for tumors larger than 3.5 cm. The individualized protocol was used for tumors located adjacent to the diaphragm, gastrointestinal tract, or gallbladder. Some adjunctive measures such as supplementary fine needle localization, local saline solution injection, and feeding vessel ablation were used to deal with different features of these liver tumors. Patients were followed regularly to assess treatment efficiency, and the tumor was considered to have early complete necrosis if no viability was found on enhanced computed tomography 1 month after RF ablation. In this series, the early necrosis rates were 95.8% for HCC (295 of 308 tumors), 94.9% for MLC (185 of 195 tumors), 91.3% for tumors larger than 3.5 cm (189 of 207 tumors), 90.7% for tumors near the gastrointestinal tract (49 of 54 tumors), 91.5% for tumors near the diaphragm (86 of 94 tumors), and 90.6% for tumors near the gallbladder (48 of 53 tumors). The local recurrence rates were 10.7% for HCC (33 of 308 tumors) and 14.9% for MLC (29 of 195 tumors). The 1-, 2-, and 3-year overall survival rates were 89.6%, 69.4%, and 59.6%, respectively, for HCC and 80.3%, 52.8%, and 30.9%, respectively, for MLC. The 1-, 2-, and 3-year survival rates in 60 patients with stage I/II HCC were 93.7%, 87.1%, and 76.2%, respectively. The incidence of major complications was 1.4% (eight of 574 sessions), which included of three hemorrhages, four injuries to adjacent structures, and one case of needle tract seeding. In RF ablation of hepatic tumors, application of a proper protocol and adjunctive measures play important roles in improving tumor necrosis rate and minimizing potential complications.

Outcome of antenatally diagnosed sacrococcygeal teratomas: single-center experience (1993-2004)

Aims Sacrococcygeal teratomas (SCTs) are the commonest neonatal tumors with an incidence of approximately 1:30,000. There are few large single-center series and even fewer describing both their antenatal and postnatal course. We report the outcome of all fetuses investigated at a tertiary fetal medicine center with this diagnosis. Method Demographic details were obtained from a prospectively maintained database. Patient records were examined for additional data including antenatal and postnatal interventions. Data were described as median (range). Results Forty-one SCTs were diagnosed antenatally during the period 1993 to 2004. Twelve were excluded from subsequent analysis (single antenatal visit or attending for second opinion [n = 6] and termination of pregnancy [n = 6]). Twelve underwent fetal intervention (laser vessel ablation [n = 4], alcohol sclerosis [n = 3], cyst drainage [n = 2], amniodrainage [n = 2], vesicoamniotic shunt [n = 1]) for fetal hydrops and polyhydramnios to aid in delivery and to prevent obstructive uropathy developing in the fetus. Of these, 3 died in utero and 9 survived to be born (median gestational age, 33 weeks [27-37 weeks]). A further 3 died in the neonatal period. There are 6 long-term survivors (50%) from this group. Seventeen infants, without intervention, were born at median gestational age 38 weeks (26-40 weeks). One infant with severe cardiac anomalies died on the day of birth. All surviving infants had definitive excisional surgery at a median of 2 days (1-16 days). Current median follow-up of survivors is 39 months (8-86 months). There have been no recurrences. One child has mild constipation, and 3 are awaiting cosmetic revision of their scars. Conclusions The overall survival of antenatally diagnosed SCT is approximately 77%, with the development of hydrops and others requiring in utero intervention carrying a poor prognosis. Otherwise, the outcome after surgical excision is excellent.

Prediction of the ablated area by the spread of microbubbles during radiofrequency ablation of hepatocellular carcinoma

Radiofrequency ablation (RFA) is effective for the treatment of hepatocellular carcinoma (HCC). To prevent the ablation of adjacent organs and vessels, the spread of microbubbles generated by heating during RFA was observed by ultrasonography (US) and used to predict the ablated area; however, several reports documented that discrepancies existed between the spread of microbubbles and the ablated area. The spread of microbubbles during RFA was observed by US in 24 patients with HCC and the areas were compared with the defect of enhancement in contrast enhanced (CE)-US, using Levovist in the same plane. During the ablation, the posterior margin was obscure but the border could be visualized 5 min after the ablation. The size of the area of hyperechogenicity 5 min after ablation and that of the defect observed by CE-US was found to correlate (r(2)=0.91, P<0.0001). The shape of the hyperechogenicity corresponded well to the defect area, even in cases showing irregular spread of the microbubbles. The observation of microbubbles during RFA can predict the ablated area and might be useful to prevent the unfavorable ablation of adjacent organs and vessels.

Standard treatment of liver malignancies with radiofrequency ablation

To investigate the role of standard treatment with ultrasound-guided radiofrequency ablation (RFA) in improving the treatment level of liver malignancies. 302 patients with 476 liver malignancies were treated with established protocol and adjuvant measures and subjected to efficiency analysis. In the 302 patients, 181 had 282 hepatocellular carcinomas (HCC) with a mean diameter of 4.2 cm, and 121 had 194 metastatic liver carcinomas (MLC) with a mean diameter of 3.9 cm. According to UICC-TNM system 50 patients (27.6%) were in stage I/II and 131 (72.4%) in stage III/IV (including 39 patients with recurrent HCC after surgical resection). A standard protocol and an individualized protocol were used to treat the tumors based on their size, shape and special location such as the distance from diaphragm, gallbladder and gastrointestinal tract. Needle placement method and operation skill for the tumor region adjacent to important structures were described. Some adjuvant measures such as supplementary fine needle localization, local saline injection and feeding vessel ablation were used to improve RFA efficacy in tumors with different features. Local ablation of bleeding site and haemostatic administration systemically were adopted to deal with bleeding. For the patients with tumor adjacent to gastrointestinal tract, prolonged fasting after the RFA procedure was required. the patients were followed up regularly to assess the treatment efficiency, and the tumor was considered complete necrosed if no viability was found on enhanced CT or enhanced US one month after RFA. The tumor necrosis rate was 95.7% (270/282 tumors) for HCC, 94.8% (184/194 tumors) for MLC, 91.1% (51/56 tumors) for tumor near gastrointestinal tract, 88.5% (69/78 tumors) for tumors near diaphragm, and 94.3% (49/52 tumors) for tumor near gallbladder. The local recurrence rate was 10.3% (29/282 tumors) for HCC and 14.4% (28/194 tumors) for MLC. The 1, 2 and 3 year overall survival rates were 87.6%, 67.4% and 58.6% in the HCC patients, and 87.4%, 48.2%, 25.3% in the MLC patients respectively. The 1, 2 and 3 year survival rates of 50 HCC patients in early (I-II) stages were 90.7%, 85.9% and 73.7%, respectively. The incidence of complications was 2.2% (13/583 sessions), including 5 cases of hemorrhage, 1 case colon perforation, 8 cases of injury of adjacent structures. Application of proper protocol and adjuvant measures plays an important role in improving tumor ablation rate. Knowledge about possible complications and their control may increase the treatment efficacy and help to promote the use of RFA technique.

New micro vertical scissors for the surgical ablation of retinal angiomatous proliferation

To develop new micro vertical scissors for the ablation of retinal angiomatous proliferation (RAP) to minimize possible retinal damage. Interventional case report. New micro vertical scissors were developed and used for the ablation of RAP vessels. The length of the inner side of the tip is 180 microm, which is approximately one seventh that of regular vertical scissors. The scissors handled easily and the RAP vessels were ablated with less retinal damage compared with that associated with use of standard vertical scissors. Postoperatively, intraretinal hemorrhage was reduced and hyperfluorescence seen on indocyanine green angiography resolved. The new micro vertical scissors developed for the ablation of RAP vessels can be used safely and effectively during this surgical procedure.

The Placenta

The human placenta is a discoid organ that has a hemochorial relationship with the mother. That is to say, the trophoblast that covers the villi is in direct contact with the maternal blood. Transfer of substances has to traverse the syncytiotrophoblast, cytotrophoblast, villous basement membrane, fetal capillary bed, and its endothelium. Although the placenta is the most available tissue, it is the least thoroughly investigated organ, and many aspects of its control still are unknown. Especially deficient is our knowledge of the genetic control of its many functions. The placenta also has a different imprinting pattern (paternal imprinting) from that of the embryo. The prevailing sentiment is that once delivery has occurred, it is a superfluous tissue that only needs to be discarded. There are many reasons, however, that knowledge of placental pathology can aid materially in a better understanding of newborns who have anomalies or neonatal problems. Further, a detailed examination of the placenta at birth can provide a better insight into prenatal life and its possible disturbances than is possible from notes in the history of the patient. The shape of the placenta is extremely variable (Fig. 1), probably due to placental location, its interaction with the endometrium, and uterine shape. The placenta implants anywhere in the uterus, but most commonly, it is in an anterior or posterior location. Much less often it is on the fundus. The shape often can be understood best by considering the history of its implantation. The reason for a specific shape can be derived further from the frequently aberrant shapes of twin placentas where competition for space in the uterus, a phenomenon that has been termed “trophotropism,” can be inferred to have existed. This term was used initially in attempts to explain the placental features in the uncommon event of a placenta …

Interstitial vascularity in fibrosing alveolitis.

The aim of this study was to evaluate interstitial vascularity in cryptogenic fibrosing alveolitis (CFA) and in fibrosing alveolitis associated with systemic sclerosis (FASSc). Open lung biopsies from eight patients with CFA, nine patients with FASSc, and normal lung from 12 patients undergoing surgery for lung cancer were studied. Markers for endothelial cells (CD34) and cell proliferation (proliferating cell nuclear antigen) were localized by sequential immunohistochemistry and quantified using computer-assisted analysis. Vascular distribution was evaluated at increasing distances (up to 160 microm) from the airspaces. Vessel density was markedly reduced in both FASSc (3.9%) and in CFA (4.5%) compared with control samples (20.4%, p < 0.0001). The percentage of tissue occupied by vessels decreased with increasing distance from alveoli in control samples but not in CFA or FASSc samples. Endothelial cell proliferation indices were increased in FASSc but not in CFA, compared with control samples (p = 0.006). In conclusion, there is net vascular ablation and redistribution of blood vessels in areas of interstitial thickening in both CFA and FASSc, which may contribute to gas exchange impairment.

Excimer laser (308 nm) recanalisation of in-stent restenosis: thermal considerations.

Excimer laser recanalisation of in-stent restenosis may be a viable modality for improving coronary patency. However, the presence of arterial stents modifies the thermal properties of the irradiated area and may alter temperature patterns generated during ablation. The goal of this study was to evaluate, in vitro, temperature changes during excimer laser ablation of stented vessels and compare them with those obtained from unstented (control) vessels. Six different stent types (AVE Microstent-II, AVE-GFX, ACS Multi-link, JJ Palmaz-Schatz, JJ Crown, and NIR) were deployed in freshly excised porcine coronary vessels. Three control unstented samples were also measured. Blood or saline was infused through the vessels, while the tissue environment was kept at approximately 37 degrees C. A 308 nm excimer laser (Spectranetics, CVX300) with an eccentric 2.0 mm laser catheter (Spectranetics, EII) delivered two trains of 200 pulses each, 10 s apart, at 60 mJ/mm2, and 40 Hz, simulating maximum clinical exposure. The catheter was positioned midway in the stent, first coaxially parallel to the vessel wall, and then at an angle against the stent and vessel wall. Temperature measurements (n= 168 for blood, n=96 for saline) were performed with a approximately 210 microm diameter, fast-response thermocouple with 0.1 degrees C resolution. The probe was positioned to within approximately 250 microm from the inner surface of the vessels. Tissue temperature was measured at the catheter tip and at the distal and proximal edges of the stents. Maximum recorded temperatures for coaxial and angular alignment, did not exceed 42.2 degrees C (approximately 6 degrees C above baseline) and 54.2 degrees C (approximately 18.1 degrees C above baseline) respectively, for all stents types tested, controls, and all probe locations. Both stented and unstented vessels exhibited comparable temperature gradients. The observed maximum temperatures, obtained under extreme lasing conditions, indicated that 308 nm ablation, in the presence of stents under blood or saline infusion, produces clinically acceptable temperatures.

Fetoscopic laser ablation of placental vessels in severe previable twin-twin transfusion syndrome: De Lia J.E.; Kuhlmann R.S.; Harstad T.W.; Cruikshank D.P. Am J Obstet Gynecol 1995 172/4 I (1202–1211)

Fetoscopic laser ablation of placental vessels in severe previable twin-twin transfusion syndrome: De Lia J.E.; Kuhlmann R.S.; Harstad T.W.; Cruikshank D.P. Am J Obstet Gynecol 1995 172/4 I (1202–1211)

Fetoscopic laser ablation of placental vessels in severe previable twin-twin transfusion syndrome

OBJECTIVE: We undertook a pilot study to determine the feasibility and efficacy of fetoscopic laser occlusion of chorioangiopagous vessels in severe previable twin-twin transfusion syndrome. STUDY DESIGN: A total of 35 patients were referred to the investigators with ultrasonographic findings consistent with twin-twin transfusion syndrome, posterior placental implantation, gestational age < 25 weeks, and clinical hydramnios. Placental vessel occlusion was performed with a rigid 2.9 × 3.85 mm dual-channel fetoscope and neodymium:yttrium-aluminum-garnet laser light. RESULTS: Of the original 35 patients, 5 were eliminated preoperatively and 4 intraoperatively for various factors. The 26 treated patients had a mean gestational age of 20.8 weeks (range 18 to 24) and a mean fundal height of 36.1 cm (range 29 to 44). One patient has surviving triplets, 8 have surviving twins, 9 have a single survivor (2 neonatal and 7 fetal deaths occurred in this group), and 8 have no survivors (all had pregnancy loss within 3 weeks of treatment). The cases with survivors were delivered for obstetric indications at a mean of 32.2 weeks (range 26 to 37), having gained a mean of 11.7 weeks (range 6 to 17) in utero. Fifty-three percent ( 28 53 ) of the fetuses survived with 96% ( 27 28 ) developing normally at a mean age of 35.8 months (range 1 to 68). Thirty-three of 35 placentas were monochorionic with chorioangiopagous vessels on gross and microscopic evaluation. CONCLUSIONS: Fetoscopic laser occlusion of chorioangiopagous vessels is technically feasible and improves the course and outcome of severe twin-twin transfusion syndrome in previable fetuses.

Laser management of anterior epistaxis

Epistaxis is a common condition that often resolves with home remedies or with the attention of a primary care physician. However, 5% to 10% of patients suffer intractable epistaxis that requires the attention of an otolaryngologist. Among these cases, we may be faced with a patient who suffers recurrent epistaxis over a period of weeks to months that is associated with an anterior septal source. Conservative methods of packing and cauterization have failed and the patient suffers the annoyance, disability, and possible serious medical sequelae of significant blood loss. We introduce the results of a new surgical method for the management of intractable epistaxis from an anterior source. This technique abandons the laser ablation of septal vessels from outside the mucosa in favor of an approach from beneath the tissue surface. Standard septal surgical instruments are used to create familiar mucoperichondrial flaps where endoscopic visualization then permits Nd-YAG or argon laser obliteration of the septal vessels from beneath the mucosal surface.

Flash Lamp‐Pumped Dye Laser Treatment of Telangiectasia

Although many treatment modalities are effective in the treatment of essential telangiectasia, most have a risk of scarring and or incomplete obliteration of the dilated vessels. The Candela flash lamp-pumped dye laser has been regarded as highly selective for blood vessel ablation with virtually no risk of scarring. To present a study of 182 patients who underwent this treatment. Good to excellent response was seen in 97.5% of these patients. No scars were seen in any of the patients studied. Patients described the degree of discomfort as mild to moderate and found the post-treatment purpura an acceptable phase of healing, if advised preoperatively. We found the laser to be safe and effective in the treatment of facial telangiectasia.