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Hasan Yilmaz

Publications and source records attributed to Hasan Yilmaz.

17 recordsLinked to original sources
PubMed2006

Preclinical testing of a new clot-retrieving wire device using polyvinyl alcohol hydrogel vascular models.

INTRODUCTION: Cerebral embolism is the principal cause of cerebral infarction. Recently, mechanical embolectomy has been proposed as an effective method. We performed a preclinical evaluation of a new mechanical clot-retrieving wire. METHODS: This clot-retrieving wire consisted of three nitinol loops at the tip of a microguidewire. These three loops could be collapsed into a 0.018-inch wire compatible microcatheter. Each loop was 8 mm long and 3.5 mm wide. For simulation, polyvinyl alcohol (PVA) vascular anatomical models of the human carotid (eight models) and vertebrobasilar (three models) circulation were constructed. A pulsatile flow circulation system was used. Embolic clots were produced using pig blood plasma. The microcatheter and the microguidewire were advanced beyond the clot. The wire was then exchanged for the retrieving wire. The microcatheter was then pulled slightly back to open the loops. The clot was then caught by withdrawal of the system. Once caught, the clot was retrieved to the guiding catheter tip. We investigated the following points: ease of device deployment, clot capture ability, clot removal against blood flow and removal of the clot out of the introducer system. RESULTS: A total of 104 procedures were performed in 11 PVA models and evaluated. The drop rate was 19%. We succeeded in partial and total recanalization in 51.0% of the procedures (53/104) within 30 minutes. CONCLUSION: This new clot-retrieving wire could be useful for mechanical clot extraction in stroke.

Embolectomy↗
PubMed2006

Orthostatic mesodiencephalic dysfunction after decompressive craniectomy.

An extreme syndrome of the trephined after decompressive craniectomy is reported here. The most extensive clinical syndrome observed was established over 4 weeks and consisted of bradypsychia, dysartria, and limb rigidity with equine varus feet predominating on the right. The syndrome was aggravated when the patient was sitting with the sequential appearance over minutes of a typical parkinsonian levodopa-resistant tremor starting on the right side, extending to all four limbs, followed by diplopia resulting from a left abducens nerve palsy followed by a left-sided mydriasis. All signs recovered within 1-2 h after horizontalisation. It was correlated with an orthostatic progressive sinking of the skin flap, MRI and CT scan mesodiencephalic distortion without evidence of parenchymal lesion. Brain stem auditory evoked potential wave III latency increases were observed on the right side on verticalisation of the patient. EEG exploration excluded any epileptic activity. Symptoms were fully recovered within 2 days after cranioplasty was performed. The cranioplasty had to be removed twice due to infection. Bradypsychia, speech fluency, limb rigidity and tremor reappeared within a week after removal of the prosthesis. While waiting for sterilisation of the operative site, the symptoms were successfully prevented by a custom-made transparent suction-cup helmet before completion of cranioplasty.

Adult↗
PubMed2006

Intravenous versus combined (intravenous and intra-arterial) thrombolysis in acute ischemic stroke: a transcranial color-coded duplex sonography--guided pilot study.

BACKGROUND AND PURPOSE: Determine feasibility and safety of intravenous (IV) versus combined (IV-IA [intra-arterial]) thrombolysis guided by transcranial color-coded duplex sonography (TCCD). METHODS: Thirty-three patients eligible for IV thrombolysis, within 3 hours of onset of symptoms, with occlusion in middle cerebral artery territory (TCCD monitoring, thrombolysis in brain ischemia [TIBI] flow grade [0-3]), underwent IV thrombolysis (tissue plasminogen activator, 0.9 mg/kg). In case of recanalization (modification of TIBI score > or =1) after 30 minutes IV thrombolysis was continued over 1 hour; otherwise, it was discontinued, with subsequent IA thrombolysis. Recanalization was determined by TIBI (TCCD) and angiographically by thrombolysis in myocardial infarction (TIMI) flow grades. Clinical outcome measures were assessed at baseline, 24 hours (NIHSS) and 3 months (modified Rankin Scale). RESULTS: In the IV group, 10/17 patients (59%) with complete or partial recanalization after 30 minutes had a favorable outcome at 3 months (modified Rankin Scale 0 to 2). TIBI flow grades 3 to 5 after 30 minutes of IV thrombolysis predicted a good prognosis compared with TIBI grades 1 to 2 (P<0.05). In the combined IV/IA therapy group (no recanalization after 30 minutes), 9/16 patients (56%) had a favorable outcome at 3 months. One symptomatic intracerebral hemorrhage occurred in each group. CONCLUSIONS: Combined IV-IA versus IV thrombolysis guided by TCCD was feasible and safe. Recanalization after 30 minutes of IV thrombolysis led to a favorable outcome in 59% of the patients, provided TIBI flow grades were of 3 to 5. In the absence of early recanalization during IV thrombolysis, there was clinical benefit to proceed to IA therapy for a significative proportion of patients (56%).

Acute Disease↗
PubMed2006

Intracranial aneurysm stenting: follow-up with MR angiography.

Intracranial stenting is increasingly being used to treat intracranial aneurysms and stenoses. We wanted to assess the utility of magnetic resonance angiography (MRA) in the follow-up of patients treated with various types of intracranial stents and to assess the utility of performing gadolinium-enhanced MRA. A total of 19 patients having undergone intracranial stenting for aneurysms were imaged by MRI at 1.5T. A total of 20 stents were placed in 19 patients. In addition to conventional T2- and diffusion-weighted MRI, 3D time-of-flight MRA was performed before and after contrast administration. In the case of metallic INX stents (N = 7), there was a signal drop at the level of the vessel. which did not allow to evaluating the parent vessel, whereas this was visible in Nitinol stents (N = 8). Additionally a stent with a wire had a small artifact (N = 3). Contrast administration also improved vessel lumen visualization. In the case of Nitinol stents, MRA can be used to reliably demonstrate the vessel lumen after intracranial stenting. The use of postcontrast 3D time-of-flight imaging helps improve the intraluminal definition.

Adult↗
PubMed2006

The petrosquamosal sinus in humans.

This article provides a comprehensive description of the morphology of the human petrosquamosal sinus (PSS) derived from original observations made on 13 corrosion casts of the cranial venous system combined with routine clinical imaging studies in two patients. The PSS is not a rare finding in the adult human. In particular, continuous developments in imaging techniques have made radiologists become increasingly aware of this anatomical entity in recent years. The role of the PSS as a major encephalic drainage pathway and its potential implication in pathological conditions such as intracranial venous hypertension are discussed.

Adult↗
PubMed2005

Comparison of two methods (microscopy and enzyme-linked immunosorbent assay) for the diagnosis of amebiasis.

Diagnosis of amebiasis is usually performed on a clinical basis alone in most endemic countries having limited economic resources. This epidemiological study was conducted using modern diagnostic tests for amebiasis in the southeastern region of Turkey, an endemic area for amebiasis. The population of this study included patients with symptomatic diarrhea/dysentery attending both Yuzuncu Yil University, Van and Harran University, Sanliurfa, Turkey. A total of 380 stool specimens were collected and examined for Entamoeba by light microscopy (fresh, lugol, and trichrome staining) and stool antigen detection based- enzyme-linked immunosorbent assay (EIA) test (TechLab Entamoeba histolytica II). 24% (91/380) of stool specimens were positive for E. histolytica/Entamoeba dispar trophozoites/cysts microscopically using trichrome staining. 13% (51/380) of the stool specimens were found to be positive for E. histolytica by the EIA test, including 15% (14/91) of microscopy (+) stool specimens and 13% (37/289) of microscopy (-) stool specimens. Enteric parasites were common in these populations with 66% (251/380) of the study population harboring more than one parasite. In addition to the 13% (51/380) of patients determined to have E. histolytica by EIA, eighty-six patients (22.6%) had Blastocystis hominis, 54 (14.2%) Entamoeba coli, 44 (11.5%) Giardia lamblia, 16 (4.2%) Chilomastix mesnili, 15 (3.9%) Iodamoeba bütschlii, 12 (3.1%) Hymenolepis nana, 9 (2.3%) Endolimax nana, 9 (2.3%) Dientamoeba fragilis, and 8 (2.1%) had Ascaris lumbricoides. We concluded that E. histolytica infection was found in 13% of the patients presenting with diarrhea in Van and Sanliurfa Turkey.

Adolescent↗
PubMed2005

Myocardial bridging of obtuse marginal branch of the left circumflex artery associated with congenital corrected transposition of the great arteries.

A 54-year-old male was admitted to the emergency department with progressive dyspnea and chest pain during exercise. Congenital corrected transposition of the great arteries was detected on echocardiography. Coronary angiography revealed myocardial bridging on the obtuse marginal branch of the left circumflex coronary artery. Being a rare complex cardiac anomaly we discussed the congenitally corrected transposition of the great arteries (CCTGA) in association with myocardial bridging.

Comorbidity↗
PubMed2005

Pelvic osteoplasty in osteolytic metastases: technical approach under fluoroscopic guidance and early clinical results.

PURPOSE: To describe a new fluoroscopically guided technique for osteoplasty (or cementoplasty) of the superior and inferior pubic rami and ischial tuberosities and to provide information about the access routes and initial results on pain management after this technique. MATERIALS AND METHODS: Twenty-three lytic metastases of the superior and inferior pubic rami and ischial tuberosities were treated in 14 consecutive patients. Percutaneous access of the bones was performed under fluoroscopy. All patients had pain refractory to radiation and narcotic therapy and were unsuitable candidates for surgery according to multidisciplinary consensus. RESULTS: Technical success was achieved in all cases. Clinically, effective pain relief was obtained in 92% of patients. One intraarticular asymptomatic minor complication and one major complication resulting from leakage near the pudendal nerve were observed. The latter was subsequently treated by radiofrequency ablation. CONCLUSION: Pelvic osteoplasty appears to be a safe and highly effective palliative therapy for painful osteolytic malignant bone metastases.

Aged↗
PubMed2005

Aural myiasis in children and literature review.

Myiasis is a disease caused by fly larvae. The term "myiasis" is derived from the Greek word "myia" meaning fly. Aural myiasis is a rare clinical state and occurs frequently in children. In this article, six children with aural myiasis, caused by the fly larvae, are reported because of unusual presentation. All of the children with aural myiasis were associated with chronic otitis media. In the treatment, a combination of suctioning and alligator forceps was used to remove maggots under the light microscopic field. Additionally, antibiotics were used in all children. Thus, aural myiasis is successfully treated by direct extraction of larvae and application of preventative methods.

Animals↗
PubMed2004

Thrombolysis for ischemic stroke in patients with old microbleeds on pretreatment MRI.

BACKGROUND: Old asymptomatic microbleeds (MBs) visualized on T2-weighted MRI are indicative of microangiopathy. They may be a marker of increased risk of intracerebral hemorrhage (ICH) following thrombolysis. However, data regarding this potential risk are limited. METHODS: A retrospective analysis of pretreatment T2-weighted MRI was performed in consecutive stroke patients who received intravenous tissue plasminogen activator (tPA). We aimed to assess the impact of MBs on the risk of cerebral bleeding. The frequency and location of MBs were assessed and compared with the location of ICH after thrombolysis. RESULTS: Forty-four patients were studied. MBs were present on pretreatment MRI in 8 cases (18.2%). At day 1, symptomatic ICH occurred in none of 8 patients with MBs versus 1 of 36 patients without (NS). At day 1, ICH occurred in 3 of 8 patients with MBs versus 10 of 36 patients without (NS). At day 7, symptomatic ICH occurred in 1 of 8 patients with MBs versus 2 of 36 patients without (NS). At day 7, ICH occurred in 5 of 8 patients with MBs versus 12 of 36 patients without (NS). No ICH occurred at the site of an MB. ICH occurred within the ischemic area in all patients who bled. CONCLUSIONS: Our study suggests that stroke patients with a small number of MBs on pretreatment MRI could be treated safely with thrombolysis. Larger prospective studies are needed to address the predictive value of detection of MBs with regard to the risk of tPA-induced ICH.

Acute Disease↗
PubMed2004

Human fasciolosis in Van province, Turkey.

This investigation was carried out to determine the frequency of the fasciolosis in Erciş, a town in the Van province located in the Eastern Turkey. The study includes 500 asymptomatic subjects (322 males and 178 females) whose ages ranged from 5 to 75 years. In all subjects, stool samples were examined at initiation of the study and one week later to rule out pseudoparasitosis. The methods of flotation (in saturated saline solution) and sedimentation (in formalin-ether solution) were used in examination of the stool samples. Fasciola hepatica eggs were detected in nine (1.8%) out of 500 subjects. In conclusion, our data showed that the prevalence of human fasciolosis was high in our region because watercress consumption was common. We also think that human fasciolosis is more frequent than expected in Turkey. To determine the exact prevalence of the disease, extensive serological investigations should be performed in different regions of Turkey.

Adolescent↗
PubMed2004

The effect of combination therapy on regression of left ventricular hypertrophy in cases with hypertension.

OBJECTIVE: Up to this date, it is well shown that several antihypertensive drugs have different regressive effect on left ventricular hypertrophy (LVH). However, there are different studies regarding the effect of antihypertensive combination therapies on regression of LVH. In this study, 2 different combinations ACE-I plus calcium channel blocker and ACE-I plus diuretic were compared in cases with hypertension whose BPs were not controlled by ACE-I alone. METHODS: Forty patients with mild to moderate hypertension were included in this study. The treatment was continued for 6 months in the Faculty of Medicine at Ege University, Turkey, between January and December 2003. Adequate response with lisinopril 20 mg/daily failed to be achieved in all patients. Patients divided into 2 groups. There were no differences between the groups in patients' age, blood pressure (BP) and other clinical and laboratory range. First group patients received lisinopril 20 mg + nifedipine GITS 30 mg and second group patients received lisinopril 20 mg + hydrochlorothiazide 25 mg. The treatment was continued for 6 months. Blood pressure were measured every 2 weeks, echocardiographic findings, and blood and urinary analysis were performed before and at the end of treatment. RESULTS: Systolic and diastolic BP decreased significantly in both groups and no significant difference regarding BP was found between the 2 groups. Left ventricular mass index also decreased significantly in both groups. However, in the first group left ventricular mass index decreased more compared to the second group. CONCLUSION: The effect of combination therapies with angiotensin converting enzyme inhibitor (ACE-I) plus diuretic and ACE-I plus calcium channel blocker on systolic and diastolic BP are similar. However, when LVH is present, regressive effect of the combination of ACE-I plus calcium channel blocker is superior to the combination of ACE-I plus diuretic.

Adult↗
PubMed2003

Early magnetic resonance imaging prediction of arterial recanalization and late infarct volume in acute carotid artery stroke.

In patients with acute ischemic stroke, early recanalization may save tissue at risk for ischemic infarction, thus resulting in smaller infarcts and better clinical outcome. The hypothesis that clinical and diffusion- and perfusion-weighted imaging (DWI, PWI) parameters may have a predictive value for early recanalization and final infarct size was assessed. Twenty-nine patients were prospectively enrolled and underwent sequential magnetic resonance imaging (1) within 6 hours from hemispheric stroke onset, before thrombolytic therapy; (2) at day 1; and (3) at day 60. Late infarct volume was assessed by T2 -weighted imaging. At each time, clinical status was assessed by the National Institutes of Health Stroke Scale (NIHSS). Twenty-eight patients had arterial occlusion at day 0 magnetic resonance angiography (MRA). They were classified into two groups according to day 1 MRA: recanalization (n = 18) versus persistent occlusion (n = 10). Any significant differences between these groups were assessed regarding (1) PWI and DWI abnormality volumes, (2) relative and absolute time-to-peak (TTP) and apparent diffusion coefficient within the lesion on DWI; and (3) day 60 lesion volume on T2 -weighted imaging. Univariate and multivariate logistic regression analysis showed that the most powerful predictive factors for recanalization were lower baseline NIHSS score and lower baseline absolute TTP within the lesion on DWI. The best predictors of late infarct size were day 0 lesion volume on DWI and day 1 recanalization. Early PWI and DWI studies and day 1 MRA provide relevant predictive information on stroke outcome.

Acute Disease↗
PubMedDate not supplied

Rheological changes after stenting of a cerebral aneurysm: a finite element modeling approach.

Hemodynamic changes in intracranial aneurysms after stent placement include the appearance of areas with stagnant flow and low shear rates. We investigated the influence of stent placement on blood flow velocity and wall shear stress of an intracranial aneurysm using a finite element modeling approach. To assess viscosity changes induced by stent placement, the rheology of blood as non-Newtonian fluid was taken into account in this model. A two-dimensional model with a parent artery, a smaller branching artery, and an aneurysm located at the bifurcation, before and after stent placement, was used for simulation. Flow velocity plots and wall shear stress before and after stent placement was calculated over the entire cardiac circle. Values for dynamic viscosity were calculated with a constitutive equation that was based on experimental studies and yielded a viscosity, which decreases as the shear rate increases. Stent placement lowered peak velocities in the main vortex of the aneurysm by a factor of at least 4 compared to peak velocities in the main artery, and it considerably decreased the wall shear stress of the aneurysm. Dynamic viscosity increases after stent placement persisted over a major part of the cardiac cycle, with a factor of up to 10, most pronounced near the dome of the aneurysm. Finite element modeling can offer insight into rheological changes induced by stent treatment of aneurysms and allows visualizing dynamic viscosity changes induced by stent placement.

Blood Flow Velocity↗