Biomedical subjects

Dimitrios Karnabatidis

Publications and source records attributed to Dimitrios Karnabatidis.

17 recordsLinked to original sources

PubMed2006

Splenic arteriovenous fistula and sudden onset of portal hypertension as complications of a ruptured splenic artery aneurysm: Successful treatment with transcatheter arterial embolization. A case study and review of the literature.

Splenic arteriovenous fistula (SAVF) accounts for an unusual but well-documented treatable cause of portal hypertension([1-4]). A case of a 50-year-old multiparous female who developed suddenly portal hypertension due to SAVF formation is presented. The patient suffered from repeated episodes of haematemesis and melaena during the past twelve days and thus was emergently admitted to hospital for management. Clinical and laboratory investigations established the diagnosis of portal hypertension in the absence of liver parenchymal disease. Endoscopy revealed multiple esophageal bleeding varices. Abdominal computed tomography (CT) and transfemoral celiac arteriography documented the presence of a tortuous and aneurysmatic splenic artery and premature filling of an enlarged splenic vein, findings highly suggestive of an SAVF. The aforementioned vascular abnormality was successfully treated with percutaneous transcatheter embolization. Neither recurrence nor other complications were observed.

Aneurysm, Ruptured↗

PubMed2006

Application of paclitaxel-eluting metal mesh stents within the pig ureter: an experimental study.

OBJECTIVE: The purpose of the present study is to compare the standard bare metal stents (BMS) with the Paclitaxel-Drug Eluting Stent (DES) in the ureter of a pig model. MATERIALS AND METHODS: We report on an experimental study with ten female pigs weighing between 25 and 30 kg. The stents were randomly placed in either the right or left ureter in each of 10 study animals, for a total of 20 stented ureters. Ten ureters were stented with an R-Stent (Orbus Medical Technologies, Hoevelaken Netherlands), and ten with a Paclitaxel-Eluting Coronary Stent (Boston Scientific, Natick, MA, USA). Patency was measured by radiograph of the nephrostomy tract, intravenous urography and virtual endoscopy at 24 hours and 21 days after the initial procedure, respectively. RESULTS: Free flow of urine through the stents into the bladder was documented in all stented ureters 24 hours after stent insertion by radiograph of the nephrostomy tract. At the 21 day follow-up examination, 5 R-Stents were found to be completely occluded and two partially stenosed, whereas no occluded stent was detected in the Paclitaxel-DES group. Pathology examination of the stents at 21 days follow-up showed that the obstructed R-Stents generated severe inflammation with metaplasia of the urothelium. The Paclitaxel-Eluting MS generated a mild inflammatory response within the ureteral lumen at the site of the stent, without hindering ureteral patency. R-stents proved to develop more hyperplasia compared to the Paclitaxel-Eluting MS. CONCLUSIONS: Paclitaxel-DES, when compared with the standard R- Stent BMS, generated less inflammation and/or hyperplasia of the surrounding tissues, thus maintaining ureteral patency. Long-term animal trials are required to further validate our results.

Animals↗

PubMed2006

Digital subtraction angiography and computer assisted image analysis for the evaluation of the antiangiogenetic effect of ionizing radiation on tumor angiogenesis.

PURPOSE: The aim of the present study was to evaluate and quantify the antiangiogenetic effect of ionizing radiation on tumor angiogenesis using digital subtraction angiography (DSA) in conjunction with computer assisted image analysis (CAIA). METHODS: Walker 256 carcinosarcoma was inoculated in both glutei of 12 Wistar rats. When the tumors reached a diameter of 1.5 cm, local irradiation of the right gluteus was performed. The left gluteus of each animal served as a control. After 24 hours of irradiation, angiography was performed, and images where digitized and subsequently processed. The effect of irradiation was observed both in big and small vessels (smaller or greater than 200 microm). RESULTS: Irradiated areas of both small and big vessels showed a statistically significant reduction in both total vessel area and length. Small vessels showed a greater trend toward suppression by irradiation (not statistically significant). CONCLUSION: Irradiation had a deleterious effect in both macro- and micro-blood supply of a tumor. The use of CAIA enhanced the efficacy of DSA and enabled the in vivo identification of the effect of irradiation on various caliber vessels as well as the ratios of total length and total area of small and big vessels.

Angiography, Digital Subtraction↗

PubMed2005

Hemobilia secondary to hepatic artery pseudoaneurysm: an unusual complication of bile leakage in a patient with a history of a resected IIIb Klatskin tumor.

We report a case of a 74-year-old woman with a 16-year history of a double bilo-enteric anastomosis due to resected hilar cholangiocarcinoma (Type IIIb Klatskin tumor). The patient presented with cholangitis secondary to benign anastomotic stenosis which resulted in a large intrahepatic biloma. In order to restore the patency of the anastomosis and overcome cholangitis, several attempts took place, including endobiliary stenting, balloon-assisted biloplasty and transhepatic billiary drainage. Anastomotic patency was achieved, complicated, however, by persistent upper gastro-intestinal bleeding, presented as hemobilia. A biloma-induced pseudoaneurysm of the left hepatic artery was diagnosed. This had ruptured into the biliary tract, and presented the actual cause of the hemobilia. Selective embolism of the pseudoaneurysm resulted in control of the hemorrhage, and was successfully combined with transhepatic dilatation of the anastomosis and percutaneous drainage of the biloma. The patient was ultimately cured and seems to be in excellent condition, 5 mo after treatment.

Aneurysm, False↗

PubMed2005

Outflow protection filters during percutaneous recanalization of lower extremities' arterial occlusions: a pilot study.

PURPOSE: Filter devices are already employed for the protection of carotid, coronary and renal distal vascular bed during endovascular procedures. This is a pilot study investigating their feasibility, safety and distal emboli protection capability during recanalization of lower extremities' acute and subacute occlusions. MATERIALS AND METHODS: Study population included 16 patients, 11 with a subacute arterial occlusion and 5 with an acute episode. The Trap filter (Microvena, USA) and its successor the Spider filter (EV3, USA) were utilized. Subacute occlusions were dealt with standard angioplasty and stenting procedures, while acute ones were managed primarily with Angiojet rheolytic thrombectomy. Outflow arterial tree was checked angiographically in-between consequent procedural steps. Embolic material collected after filter recovery was analyzed histopathologically. Patients' follow-up was scheduled at 1 month. RESULTS: Seventeen filter baskets were applied in the recanalization of 16 target lesions in total. Mean length of the occluded segments was 6.1 (range: 2-15 cm; S.D. = 3.7 cm). Mean in situ time of the filters was 38.75 min (range: 20-60 min; S.D. = 12.71 min). Technical success rate of deployment and utilization of the filtration devices was 100% (17/17). Procedural success rate of the recanalization was 100% (16/16) without any clinical or angiographic evidence of periprocedural distal embolization. Macroscopic particulate debris was extracted from all the filters (17/17) containing fresh thrombus, calcification minerals, cholesterol and fibrin. Mean diameter of the largest particle per specimen was 1702.80 (range: 373.20-4680.00 microm; S.D. = 1155.12 microm). No adverse clinical events occurred at 1-month follow-up with 100% limb salvage (16/16). CONCLUSION: The application of outflow protection filters is safe, feasible and efficacious in hindering distal embolization complications and safeguarding the distal capillary bed. Nevertheless, this is a pilot study in a limited group. Further studies have to be contacted in order to provide evidence for a more general use of these devices.

Angiography, Digital Subtraction↗

PubMed2005

External beam radiation therapy reduces the rate of re-stenosis in patients treated with femoral stenting: results of a randomised study.

BACKGROUND AND PURPOSE: To evaluate the feasibility and efficacy of external beam irradiation (EBI) for the prevention of re-stenosis due to neointimal hyperplasia, after percutaneous transluminal angioplasty (PTA) and stent placement of the superficial femoral artery. PATIENTS AND METHODS: A total of 60 patients with the diagnosis of superficial femoral artery stenoses or occlusions due to peripheral arterial obstructive disease underwent PTA and implantation of a self-expandable stent at their superficial femoral artery. After the procedure, patients were randomised and 30 of them received EBI (6 MV photons, total dose 24 Gy in six fractions in 2 weeks), while the rest 30 received no radiation therapy. RESULTS: EBI was technically feasible in all patients, without serious radiation related side effects. Overall, a statistically significant difference was observed in stenosis categories between the two groups at 6 months follow-up (P=0.04). More specifically, significantly more patients in the control group presented with stenosis greater or equal than 70% [EBI group 30% (9/30); control group 66.7% (20/30); P=0.009]. This difference in the percentage of re-stenosis had as a consequence significantly lower re-intervention rates among the patients of the irradiated group [17% (5/30) versus 47% (14/30); P=0.025] during the 6 months follow-up period. We also observed that the irradiated patients had re-stenosis at the stent ends, while the non-irradiated had re-stenosis at the stent ends and the lumen. Three of the irradiated patients, who discontinued the anti-platelet treatment, have shown thrombosis of the irradiated artery during the first month from the completion of the treatment. CONCLUSIONS: It is our belief that EBI is a feasible, safe and effective method for the prevention of neointimal hyperplasia at the superficial femoral artery. Further studies are deemed necessary to optimise the radiotherapy schedule.

Aged↗

PubMed2004

Intracranial aneurysms: reproduction of the surgical view using 3D-CT angiography.

Our purpose was to describe a technique for simulating the surgical view of ruptured intracranial aneurysms, using volume-rendering techniques in spiral computed tomography (CT) angiography data. The 3D (three-dimensional) rendered images were assessed by a team consisted of four radiologists, one neurosurgeon and one medical physicist. The resultant 'surgical view' image was standardized in space using a three-dimensional coordinate system, which allowed for its reproduction in the operating theatre. The surgical views are a potentially useful tool for the surgical planning of intracranial aneurysms.

Adolescent↗

PubMed2004

Extracranial internal carotid artery aneurysms: report of a ruptured case and review of the literature.

Aneurysms of the extracranial carotid arteries (ECAA) are extremely rare. Schechter et al. [1] documented 835 cases in the literature up to 1977. One hundred and sixteen cases of ECAA have been documented in the Chinese literature since 1981, suggesting a higher prevalence of carotid aneurysmal disease in China than in the West. Four percent of all peripheral artery aneurysms are reported to be ECAA [2]. Those arising from the internal carotid artery (EICAA) are even more rare. Two recent reviews [3, 4] reported 24 and 25 cases of EICAA during 21 and 17 years, respectively, the majority of them is treated surgically. Our literature review revealed only a few true EICAA managed endovascularly, but none of them with a covered stent. We describe a rare such case of ruptured atherosclerotic EICAA which was treated percutaneously.

Aged↗

PubMed2004

CT angiography with three-dimensional techniques for the early diagnosis of intracranial aneurysms. Comparison with intra-arterial DSA and the surgical findings.

INTRODUCTION: Cerebral CT angiography (CTA) is an established method applied to both the detection and treatment planning of intracranial aneurysms. The aim of our study was to compare CTA and digital subtraction angiography (DSA) findings with the surgical results mainly in patients with acute SAH and to evaluate the clinical usefulness of CTA. MATERIALS AND METHODS: During the last 2 years, 82 consecutive patients were admitted under clinical symptoms and signs suggestive of harboring an intracranial aneurysm. CT angiography performed immediately afterwards the plain CT, while DSA was performed within the first 48 h of admission. All aneurysms detected were confirmed during surgery or endovascular embolization. Repeat DSA was performed in all patients having both the initial CTA and the DSA 15 days after the onset of symptoms negative. CT angiograms and conventional angiographies were studied by a consensus of two radiologists for each technique, who performed aneurysm detection, morphological features characterization and evaluation of the technique. RESULTS: Surgical or/and endovascular treatment was performed in 45 patients and 53 aneurysms were confirmed. Using 3D-CT angiography, we detected 47 aneurysms in 42 patients. Conventional angiography depicted 43 aneurysms in 39 patients. The sensitivity of CTA for the detection of all aneurysms versus surgery was 88.7%, the specificity 100%, the positive predictive value (PPV) 100%, the negative predictive value (NPV) 80.7% and the accuracy 92.3%. Accordingly, the sensitivity of DSA was 87.8%, the specificity 98%, the PPV 97.7%, the NPV 89.1% and the accuracy 92.9%. Considering aneurysms > or =3 mm, CTA showed a sensitivity ranging from 93.3 to 100%, equal to that of DSA. CONCLUSION: Cerebral CT angiography has an equal sensitivity to DSA in the detection of intracranial aneurysms >3 mm. It has also 100% detection rate in AcoA and MCA bifurcation aneurysms, while some locations, like posterior communicating artery aneurysms, remain problematic. The delineating features of each aneurysm are better depicted with CTA due to 3D visualization. The use of digital subtraction angiography as a diagnostic tool can be limited in equivocal cases.

Adolescent↗

PubMed2003

Delayed diagnosis of a false aneurysm after lumbar arterial injury: treatment with endovascular embolization: a case report.

STUDY DESIGN: A case report is presented. OBJECTIVES: To report a case of lumbar artery pseudoaneurysm that was primarily missed, and to discuss therapeutic options. SUMMARY OF BACKGROUND DATA: In the literature, only a few cases of lumbar artery pseudoaneurysms have been reported. The diagnosis is difficult and often delayed, with a sometimes fatal outcome. The treatment is either surgery or endovascular embolization. METHODS: In a patient who survived after a fall from 20 feet (6 m) height, a relatively small retroperitoneal hematoma detected during urgent splenectomy was underestimated. Two weeks later, the underlying laceration of the lumbar artery led to the formation of a pseudoaneurysm, which then ruptured causing a large retroperitoneal hematoma and gradual complete femoral nerve palsy. RESULTS: Complete occlusion of the pseudoaneurysm and progressive regression of the retroperitoneal hematoma were achieved by two stages of endovascular embolization. The size of the hematoma was diminished gradually during a period of 12 months, whereas the femoral nerve has completely recovered. CONCLUSIONS: Traumatic rupture of a lumbar artery is a rare complication of a blunt abdominal trauma. This condition leads to a potentially massive retroperitoneal hemorrhage and shock, or to subsequent pseudoaneurysm formation and delayed retroperitoneal hematoma. This condition can be managed with either surgical or preferably endovascular intervention provided the patient is hemodynamically stable.

Accidental Falls↗

PubMed2003

Ureteral metallic stents: application of virtual endoscopy for ureteral patency control.

OBJECTIVE: In the present study we have applied virtual endoscopy (VE) in patients with ureteral metallic stents as a follow-up tool study especially in the need to define ureteral patency. METHODS: We performed the suggested technique in 6 patients with malignant ureteral obstruction treated successfully by placement of Wallstent intraureteral metallic stents, and correlated the results with antegrade nephrostomography 48 hours after initial stent placement. RESULTS: In 2 patients restenosis was observed, and in the remaining 4 patients the stented ureters remained patent during the follow up evaluation. VE and antegrade nephrostomography, were concurrent as to their findings. Moreover, VE proceeds beyond the stenotic segment, allowing visualization of the ureteral lumen both cephalad and caudal to the point of obstruction. CONCLUSION: VE is providing indeed a more accurate, direct and dynamic approach in the evaluation of a strictured ureteral lumen within the metallic stent.

Female↗

PubMed2002

Ureteropelvic junction obstruction: an innovative approach combining metallic stenting and virtual endoscopy.

PURPOSE: We report our experience with auto-expandable metallic stents for treating ureteropelvic junction obstruction. MATERIALS AND METHODS: We treated 4 patients with a mean age of 45 years who had ureteropelvic junction obstruction with placement of a self-expandable intraureteral metallic stent (Wallstent, Schneider, Zurich, Switzerland). All patients presented with recurrent ureteropelvic junction obstruction after open pyeloplasty. Excretory urography and 3-dimensional reconstruction computerized tomography were performed 1 and 6 months after stent insertion. Virtual endoscopy images were obtained at followup due to the need to define ureteral patency. RESULTS: Mean followup was 16 months (range 9 to 24). Wallstent placement was successful and immediate patency was achieved in all cases. During followup 3 patients required no further intervention and the stented ureteropelvic junction remained patent. In the remaining patient stricture recurred 2 months after initial stent insertion due to the ingrowth of scar tissue through the prosthesis. Additional intervention was deemed necessary after placing a longer 6 cm., completely coaxial overlapping metal stent. Virtual endoscopy and excretory urography findings concurred. Virtual endoscopy allows visualization of the stented ureteropelvic junction lumen cephalad and caudal to the prosthesis. It also enables easy navigation within the stent at different angles of view. CONCLUSIONS: The concept of applying metallic stents for ureteropelvic junction obstruction and adjacent adynamic ureteral segments combined with virtual endoscopy is strengthened by the results of this study.

Adult↗

PubMed2002

Externally coated ureteral metallic stents: an unfavorable clinical experience.

OBJECTIVE: The purpose of the present study was to evaluate the use of externally coated stents in patients with malignant ureteral obstruction. MATERIALS AND METHODS: We have prospectively evaluated 16 patients, 10 men and 6 women, with malignant ureteral obstruction treated successfully by placement of Passager metal stents (Boston Scientific, Natick, MA, USA) bypassing the stricture. Mean patient age was 65.6 years (range 62-78 years). Ureteral patency was confirmed 24 and 48 hours by injection of contrast material through the nephrostomy tube, and after patency confirmation the nephrostomy catheter was removed. RESULTS: All stents were positioned successfully, and the postoperative course was uneventful. In 13 cases (81.2%) the prostheses finally migrated into the bladder hindering overall ureteral patency (mean time of migration: 1.5 months). Patency was achieved in the remaining ureters (n=3), during the follow-up period (mean: 8 months, range 6-16 months), without any need for further intervention. CONCLUSION: The inappropriate anchorage and the increased ureteral peristalsis are the main causes of migration towards the bladder, thus, minimizing the usefulness of this stent for the treatment of ureteral strictures.

Aged↗

PubMed2002

Arterioureteral fistula--a rare complication of ureterolithotomy: treatment with embolization.

Fistula formation between a ureteral branch of a renal artery and the ipsilateral ureter is rare. We describe a case that followed ureterolithotomy of an impacted stone. Selective angiography with embolization of the bleeding branch was curative.

Embolization, Therapeutic↗

PubMedDate not supplied

Virtual endoscopy: navigation within pelvicaliceal system.

PURPOSE: To evaluate the use of virtual endoscopy (VE) for the investigation of the pelvicaliceal unit and the depiction of its anatomic deformities. PATIENTS AND METHODS: Two study groups were prospectively enrolled in our protocol: ten patients with nonurologic pathologies, and thus without any known deformity of the pelvicaliceal unit (group A), and five patients with caliceal obstruction (group B). Virtual endoscopy represented a non-invasive technique providing amplification of the image in three-dimensional space. RESULTS: Virtual endoscopy was feasible in all patients, and in all cases succeeded in demonstrating the threedimensional morphology of the region of interest. The entire processing time ranged from 10 to 15 minutes (mean 12.6 minutes), and the three-dimensional image could be viewed from different angles, allowing better evaluation of the collecting system and its deformities than is possible with conventional intravenous urography or percutaneous nephrostomography. CONCLUSION: Virtual endoscopy enabled the creation of endoluminal views of the renal pelvis and calices from spiral tomographic images, thereby allowing diagnostic-preoperative and postoperative evaluation of the pelvicaliceal unit.

Adult↗

PubMedDate not supplied

Percutaneous rheolytic thrombectomy for treatment of acute renal-artery thrombosis.

PURPOSE: We present our experience with percutaneous rheolytic treatment with the AngioJet thrombectomy catheter for acute renal-artery thrombosis. CASE REPORT: A 63-year-old male patient with renal-artery thrombosis presented 48 hours after the onset of acute nonradiating flank pain. Thrombosis was documented by CT angiography, 99mTc-DTPA, and digital subtraction angiography. A percutaneous thrombectomy was performed with the AngioJet catheter. At the end of the procedure, the arterial lumen was patent, and no underlying stenosis or other deformity of the arterial wall was found. Thus, the cause of the obstruction was considered to be an embolus. After the procedure, urokinase was given to prevent distal occlusions from emboli that could have escaped mechanical thrombectomy. Heparin was also administered. The patient was released from the hospital with a patent renal unit and ameliorated serum creatinine concentration. CONCLUSION: We propose the use of the AngioJet thrombectomy catheter for the percutaneous treatment of acute renal-artery thrombosis.

Aged↗

PubMedDate not supplied

Anastomoses between bronchial and coronary circulation in a porcine model: computed tomographic and angiographic demonstration.

INTRODUCTION: Although the importance of the bronchial arteries is evident in modern day thoracic surgery, the significance of their communications with coronary arteries has yet to be appreciated, especially in cases of heart-lung transplantation and aortic aneurysm repair. We conducted a study to demonstrate the coronary-bronchial anastomotic routes in a porcine model using angiography and computed tomography. METHODS: Six young female white pigs were used. The heart and lungs were removed en bloc, including the lower trachea and oesophagus. Digital subtraction angiography of the bronchial circulation and spiral computed tomography scan were performed in a three-phase study before and after administration of contrast medium. This was achieved by infusion either into the cannulated bronchial artery or into the aortic root. Macroscopic evaluation was carried out using latex infusion into the bronchial or coronary circulation. RESULTS: We demonstrated communications between the bronchial and coronary systems in 5 of 6 subjects. This communication was located at the left atrial wall and the posterior and anterior wall of the left ventricle. In one case there were further anastomoses around the right atrial wall. CONCLUSIONS: There were communications between the left coronary arteries and the bronchial arteries in the majority of cases. Digital subtraction angiography and spiral computer tomography scan can demonstrate these communications directly and indirectly by measurements of contrast enhancement within the heart wall. Our study emphasises the importance of the bronchial arteries in cases of heart-lung transplantation and repair of thoracic aortic aneurysms.

Angiography, Digital Subtraction↗