Biomedical subjects

Okan Ekinci

Publications and source records attributed to Okan Ekinci.

7 recordsLinked to original sources

PubMed2005

The value of magnetic resonance imaging for the diagnosis of arrhythmogenic right ventricular cardiomyopathy.

This study evaluated the diagnostic significance of a magnetic resonance imaging (MRI) based scoring model for identification of arrhythmogenic right ventricular cardiomyopathy (ARVC) in patients with MRI evidence of RV abnormalities. Fifty-three patients with RV myocardial abnormalities on MRI were divided into a group with ARVC 1 (n=17) and a group with other RV arrhythmias (n=37). Decision tree learning (DTL) and linear classification (based on a modified ARVC scoring model of major and minor criteria) were used to identify and assess MRI criterion information value, and to induce ARVC diagnostic rules. All major ARVC criteria were more frequent in the ARVC group. Among minor criteria regional RV hypokinesia, mild segmental RV dilatation, and prominent trabeculae were more frequent in the ARVC group while mild global RV dilatation was more frequent in the non-ARVC group. RV aneurysm achieved highest importance in ARVC diagnosis (predictive accuracy 76.8%). Better diagnostic accuracy (sensitivity 93.3%, specificity 89.5%) was achieved when the MRI score for the major and minor criteria reached threshold value of four: two major criteria, or one major and two minor, or four minor criteria. Combinations between major and minor criteria contributed to a statistically valid model for ARVC diagnosis.

Adult↗

PubMed2005

Delayed contrast-enhanced magnetic resonance imaging for the detection of autoimmune myocarditis and long-term follow-up.

MRI proved to be a valuable tool for the evaluation and monitoring of myocarditis. We report the case of a 36 year old caucasian male with an undifferentiated collagenosis who presented first four years ago with unspecific symptoms and impaired exercise capacity. On echocardiography left ventricular function was impaired as well as on MRI. In addition, after administration of Gd-DTPA an intramyocardial pathological signal enhancement was observed on TSE T1 weighted and contrast enhanced FLASH 3D IR sequences. Based on several diagnostic tests including myocardial biopsy an autoimmune myocarditis due to an undifferentiated collagenosis was diagnosed. On long time follow up over almost 3 years with repeated MRI examinations, the delayed hyper enhancement (dHE) decreased or disappeared with successful treatment, respectively. However, in the area of recurrent inflammation, a persisting area of dHE developed with a subsequent perfusion defect. This area represents myocardial fibrosis due to recurrent inflammation.

Adult↗

PubMed2005

A decrease in pulmonary vein diameter after radiofrequency ablation predicts the development of severe stenosis.

A decrease in ostial pulmonary vein (PV) diameter was observed in patients on the day after radiofrequency ablation of atrial fibrillation (AF). This study examined whether a relative reduction in PV diameter on day 1 (RRPVD1) after the procedure predicts the late development of severe PV stenosis (PVS). The study included 104 consecutive patients (mean age = 55 years, range 46-61, 34 women) with drug refractory AF. Pulmonary vein diameter was measured using MR angiography (MRA) on the day before and on day 1 after the ablation procedure. The MRA was repeated every 3 months after the procedure. Severe PVS was defined as a >70% diameter reduction from the initial ostial diameter. The cut-off of RRPVD1 was prespecified as 25% decrease in initial diameter. The data are presented as medians and interquartile range. A total of 357 PV were treated. The RRPVD1 was 0.0% (0.0-11.1%). Severe PVS was found in 18 PV during a follow-up of 12 months (range 6-13). The log-rank analysis confirmed a strong association between a RRPVD1 >/=25% and the development of PVS (hazard ratio: 7.1; 95% confidence interval 3.8-13.5, P < 0.0001). By multivariate Cox regression model, after adjustment of procedure variables, RRPVD1 was the strongest predictor of development of severe PVS. RRPVD1 >/=25% was a strong independent predictor of development of severe PVS.

Aged↗

PubMed2004

Angiographic outcome in multivessel disease (GABI II study) using new coronary device interventions and comparison with GABI I trial results.

Percutaneous coronary interventions using stents were investigated in patients with multivessel disease. Acute and long-term results were compared with those of the German Angioplasty Bypass Surgery Investigation trial in a prospective multicenter study. The study included 134 patients in whom 277 lesions were treated. Angiographic success and procedural success were achieved in 268 of 277 lesions (97%) and 118 of 134 patients (88%), respectively. Control angiography performed in 90 of 118 eligible patients (76%) exhibited restenosis in 43 of 182 lesions (24%). Multivariate regression analysis found that a diffuse lesion, the lesion and stent length, and the final luminal diameter were predictive for restenosis. Thus, immediate and long-term results of multivessel coronary intervention utilizing stents were improved compared to percutaneous transluminal coronary angioplasty of multivessel lesions. However, there is still need for improvement of long-term results, especially in particular lesion subgroups.

Adult↗

PubMed2004

N-terminal B-type natriuretic peptide predicts extent of coronary artery disease and ischemia in patients with stable angina pectoris.

BACKGROUND: B-type natriuretic peptide (BNP) and its N-terminal fragment (NT-proBNP) are elevated in patients with acute coronary syndromes and are closely linked to prognosis. Because there is only a small amount of data available concerning NT-proBNP in patients with stable angina pectoris, we aimed to determine whether NT-proBNP is of additional diagnostic value in these patients. METHODS AND RESULTS: Ninety-four patients with stable angina pectoris were prospectively included. All patients underwent exercise testing and coronary angiography, and 91 patients received thallium-201 single-photon emission computed tomography myocardial scintigraphy. NT-proBNP was analyzed at rest and after exercise testing. NT-proBNP was elevated in patients with inducible myocardial ischemia shown by single-photon emission computed tomography (396 +/- 80 pg/mL vs 160 +/- 101 pg/mL; P <.01) closely linked to the extent of coronary artery disease (CAD) (no CAD, 148 +/- 29 pg/mL; 1- or 2-vessel disease, 269 +/- 50 pg/mL; 3-vessel disease 624 +/- 186 pg/mL; P <.01). In a multivariate analysis, NT-proBNP was an independent predictor for CAD. The area under the curve of the receiver operating characteristic curve was 0.72 for NT-proBNP to predict CAD. Using an optimized cut off level of 214 pg/mL, CAD can be predicted with high accuracy. The total test efficiency of exercise testing can be improved from 1.46 to 1.52 when combined with NT-proBNP measurement. CONCLUSION: NT-proBNP is elevated in patients with stable angina pectoris and has a close correlation to disease severity. Combining the measurement of NT-proBNP with exercise testing, the test accuracy for predicting severe CAD can be improved. Our data show an incremental value of NT-proBNP in the diagnostic process of stable angina pectoris.

Aged↗

PubMed2004

Decreased pulmonary perfusion in pulmonary vein stenosis after radiofrequency ablation: assessment with dynamic magnetic resonance perfusion imaging.

STUDY OBJECTIVES: The functional impact of pulmonary vein (PV) stenosis on pulmonary perfusion after radiofrequency ablation (RFA) for atrial fibrillation (AF) has not been systematically evaluated previously. Therefore, we correlated magnetic resonance (MR) pulmonary perfusion imaging with single-photon emission CT (SPECT) perfusion and with the degree of PV stenosis (PVS) apparent on MR angiography (MRA) after RF ablation. SETTING: Joint radiology-cardiology collaborative magnetic resonance unit at the Kerckhoff Heart Center. DESIGN AND PATIENTS: This was a cohort study of 110 patients who were routinely examined by MRA after RFA for AF, whereby 51 patients with a PV diameter reduction of > 25% or with clinical symptoms (ie, dyspnea and cough) were enrolled into the study. Patients were examined at follow-up by MR perfusion imaging and MRA, and the results were compared to those from patients who underwent SPECT scanning and from a control group of 26 untreated patients. Twelve patients underwent PVS dilatation as well as 22 sequential follow-up examinations. METHODS: Pulmonary perfusion was evaluated using a dynamic contrast-enhanced three-dimensional MR perfusion sequence (1.5 T, 2.5-s temporal resolution, and 0.05 cm spatial resolution), and high-resolution, contrast-enhanced MRA was performed to measure PV diameter. PV dilatation was performed using an angioplasty catheter that was 8 to 10 mm in diameter. RESULTS: The localization and extent of perfusion defects measured by MRI or SPECT scanning were precisely matched. MR perfusion imaging detected 20 of 21 perfusion defects (sensitivity, 95.2%; specificity, 100%). PVSs and perfusion deficits correlated closely and showed the following threshold: perfusion decreased substantially in PVs 6 mm in diameter. After PVS dilatation, perfusion was restored partially after weeks, and complete normalization was seen in 4 of 12 patients (33%). CONCLUSIONS: PVSs caused severe perfusion deficits, which were reliably demonstrated by MR perfusion imaging. Clinical symptoms correlated better with MR perfusion than they did with MRA. The combination with MRA to assess underlying PVS allowed a "one-stop-shopping" MRI procedure to be carried out. The results led to alterations of RFA techniques, and therefore MRA and MR perfusion imaging may be beneficial in patient follow-up and in evaluating new ablation techniques.

Atrial Fibrillation↗

PubMed2003

Pulmonary vein diameter reduction after radiofrequency catheter ablation for paroxysmal atrial fibrillation evaluated by contrast-enhanced three-dimensional magnetic resonance imaging.

BACKGROUND: Radiofrequency catheter ablation (RFCA) is a promising intervention to treat atrial fibrillation. However, pulmonary vein (PV) stenosis after RFCA has been reported. The aim of this study was to investigate the incidence and time course of pulmonary vein stenosis after RFCA within a period of 3 months. Contrast-enhanced magnetic resonance angiography (MRA) was used to visualize pulmonary veins and was compared with radiographic angiography. METHODS AND RESULTS: Forty-six consecutive patients with symptomatic paroxysmal atrial fibrillation had RFCA in the orifice of 138 pulmonary veins. Comparison of diameters measured in 44 untreated vessels either by radiographic angiography or with MRA established the reliability of MRA (r=0.934). MRA measurements revealed an incidence of relevant diameter reductions of > or =25% or stenosis of > or =50% after RFCA of 25 of 138 (18.1%) treated vessels 1 day and/or 3 months after ablation. A progression of diameter reduction after RFCA was observed in 8.3% (maximum 75%), whereas a regression was observed in 6.3% of treated PVs. Ablation at a radial angle of >180 degrees of a pulmonary vein orifice increased the risk of diameter reduction significantly compared with ablation at a radial angle < or =180 degrees (P=0.002). CONCLUSIONS: The occurrence and progression of PV stenosis is a potential significant complication of RFCA in the orifice of pulmonary veins. These findings may have an impact on the technical performance of this intervention. In addition, long-term studies will be necessary to evaluate lumen reduction over time. MRA is a noninvasive, reproducible imaging modality for this purpose.

Angiography↗