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Biomedical subjects

Omer Goktekin

Publications and source records attributed to Omer Goktekin.

At least 19 recordsLinked to original sources
PubMed2007

Predictors of restenosis after treatment of bifurcational lesions with paclitaxel eluting stents: a multicenter prospective registry of 150 consecutive patients.

OBJECTIVES: The aim of the study was the assessment of the clinical, angiographic and procedural characteristics correlated with freedom from adverse events at 1 year in a real life setting of consecutive bifurcation lesions. BACKGROUND: Even if stent implantation has shown to be superior to conventional balloon angioplasty in most coronary lesions, bifurcation treatment with stent implantation both in main and in side branch (SB) still raises controversy. METHODS: We reviewed the results obtained in a prospective multicenter registry of 150 patients with 158 bifurcation lesions involving a SB of sufficient diameter to be treated, if necessary, with a polymer based paclitaxel eluting stent (PES, TAXUS). Two stents were used in 118 lesions (74.7%). Final kissing balloon inflation was performed in 87/118 lesions (73.7%) and in 30/40 lesions (75.0%) of the 2 and 1 stent group respectively. RESULTS: At 1-year clinical follow-up we observed 4 stent thromboses, all involving the SBs of the 2 stents group (2.7%). Unlike previous reports, revascularization involved the main vessel in the majority of patients (21/150, 14.0%). After an exploratory multivariable analysis the only parameter predictive of target lesion revascularization (TLR) (HR 0.52; CI 95% 0.11-0.86; p = 0.02) and target vessel revascularization (TVR) (HR 0.47; CI 95% 0.14-0.90; p = 0.03) was postprocedural main branch minimal lumen diameter (MB-MLD). CONCLUSIONS: In a real life setting of consecutive bifurcation lesions, thrombosis rate, concentrated in the SB and the 2-stents group, and need for target lesion revascularization remain higher than in less complex lesion subgroups treated with PES. No differences in immediate success and TLR were observed between 2 stents and 1 stent groups. The frequently observed suboptimal stent expansion and final MB-MLD predict 1 year revascularization.

Aged↗
PubMed2007

A new quantitative analysis system for the evaluation of coronary bifurcation lesions: comparison with current conventional methods.

BACKGROUND: Objective conventional quantitative angiographic systems are designed to automatically follow the contours of straight vascular segments and not of bifurcations. Recently a new analysis method was specifically developed for bifurcation lesions, able to automatically divide the lesion into three separate segments. In this study, we aimed to assess whether the smaller interaction required by the analyst could reduce the analysis time and inter and intra observer variability when compared with a conventional analysis. METHOD: We used a dedicated system (QVA-CMS V. 6.0 with the Bifurcation Module, MEDIS, Leiden, The Netherlands) applying a minimum cost algorithm tuned to detect the contours of the proximal main vessel (PMV), distal main vessel (DMV), and side-branch (SB). We assessed the intra- and the interobserver agreement in measurements of minimal lumen diameter (MLD) and percentage diameter stenosis (%DS) of the PMV and DMV, as well as of the SB ostium in 30 angiograms of patients before and after percutaneous coronary angioplasty with stenting of both branches. The consensus between measurements by two observers and by the same observer was analyzed using the intra- and interclass correlation coefficient and the reliability coefficients for all measurements. Bland-Altman plots before and after PCI were also generated to assess the relationship between variability and absolute measurements. RESULTS: Before PCI, intra- and interobserver variabilities were consistently lower for the new QVA system, with a significant difference for lesion length in the SB. Post-PCI data showed a greater variability in the assessment of diameter stenosis with both techniques. The time for analysis was significantly lower both before and after PCI for QVA compared with quantitative coronary angiography (QCA) (4.7 +/- 1.1 min versus 6.2 +/- 1.3 min, P < 0.0001). CONCLUSION: Our results demonstrate that this new quantitative bifurcation analysis system can be consistently applied to the analysis of bifurcation lesions before and after angioplasty, with an intra- and interobserver reproducibility equal to or better than the conventional analysis system with a significantly shorter analysis time.

Aged↗
PubMed2007

The effect of successful electrical cardioversion on left ventricular diastolic function in patients with persistent atrial fibrillation: a tissue Doppler study.

BACKGROUND: Changes in mitral inflow and pulmonary venous flow after electrical cardioversion (ECV) in patients with persistent atrial fibrillation (AF) were showed in many former studies. In our study we investigated the effects of ECV on diastolic parameters by using tissue Doppler imaging (TDI) in patients with persistent AF. METHODS: Forty-one (24 women) consecutive patients underwent successful elective ECV for nonvalvular persistent AF, and maintained sinus rhythm for 1 month were enrolled to the study. Transthoracic echocardiography was applied to all patients before, 24 hours after and 1 month after ECV. Mitral annular TDI parameters were also measured with mitral inflow, pulmonary venous flow, and other standard echocardiographic measurements. RESULTS: No differences in peak myocardial early velocity (Em), deceleration time of Em, and myocardial isovolumic relaxation time measured from mitral lateral annulus before, 24 hours after, and one month after ECV were found. Peak myocardial late velocity measured 24 hours after ECV increased significantly at the end of 1 month. CONCLUSION: There were not any changes in LV diastolic function except restoration of atrial mechanical contraction following ECV in patients with persistent AF.

Aged↗
PubMed2006

"Isolated" diastolic dysfunction in left ventricular outflow tract obstruction.

We sought to investigate the prescence of "isolated" diastolic disease, defined as reduced long-axis early diastolic velocity with normal systolic velocity, in 21 young patients with left outflow tract obstruction. Most patients had depressed systolic velocities despite normal ejection fractions. The close relations amond long-axis velocities suggest isolated diastolic disease is unlikely.

Adult↗
PubMed2006

Presentation, survival prospects, and predictors of death in Eisenmenger syndrome: a combined retrospective and case-control study.

AIMS: To characterize contemporary Eisenmenger patients at a large centre for adult congenital heart disease, assess survival prospects, and identify predictors of death in this population. METHODS AND RESULTS: All Eisenmenger patients under follow-up at our centre since 2000 (n=171, mean age 37+/-12 years) were included. To identify predictors of mortality, a case-control study was performed. Data including symptoms, functional class, medication, laboratory, and electrocardiographic and echocardiographic parameters are presented. Iron deficiency was common and strongly related to phlebotomy (relative risk 4.1, P<0.0001). Haemoglobin concentration was inversely related to arterial oxygen saturations in iron-replete patients (P<0.001) but not in iron-deficient patients. During a median follow-up of 67 months, 20 patients died. Survival at 40, 50, and 60 years of age was 94, 74, and 52%, respectively. When compared with healthy individuals, median survival was reduced by approximately 20 years in Eisenmenger patients and was worst in those with complex lesions. Predictors of mortality included functional class, signs of heart failure, history of clinical arrhythmia, QRS duration and QTc interval, and low serum albumin and potassium levels. CONCLUSION: Despite good short-term prognosis, life expectancy is markedly reduced in Eisenmenger patients. Markers of heart failure and parameters associated with arrhythmia are of prognostic value in terms of mortality and may guide clinicians caring for Eisenmenger patients.

Adolescent↗
PubMed2006

Comparison of ticlopidine vs. clopidogrel in addition to aspirin after paclitaxel-eluting stent implantation: insights from the TRUE (Taxusin Real-life Usage Evaluation) Study.

Thienopyridines and aspirin are beneficial in patients undergoing bare-metal stent implantation, and aspirin and clopidogrel treatment have also been proved effective after drug-eluting stent (DES) implantation. However, despite the common substitution of clopidogrel with ticlopidine because of cost or patient intolerance, there are no data on the comparison of ticlopidine vs. clopidogrel after DES implantation. We hereby compare ticlopidine vs. clopidogrel after paclitaxel-eluting stent implantation in subjects enrolled in the prospective multicenter Taxus in Real-life Usage Evaluation (TRUE) Study. Across the 505 analyzed patients (112 treated with ticlopidine and 393 with clopidogrel), similar rates of early and mid-term (7 months) adverse thrombotic events were found with either antiplatelet regimen, with the notable exception of 2 cases of late stent thrombosis in patients who had prematurely withdrawn ticlopidine treatment just 3 months after the procedure. These findings thus support the overall safety and effectiveness of ticlopidine after DES implantation, and also confirm the increased risk of late thrombosis when premature withdrawal of thienopyridines occurs.

Aspirin↗
PubMed2006

Ventricular fibrosis suggested by cardiovascular magnetic resonance in adults with repaired tetralogy of fallot and its relationship to adverse markers of clinical outcome.

BACKGROUND: Late morbidity and mortality remain problematic after repair of tetralogy of Fallot (TOF). We hypothesized that fibrosis detected by late gadolinium enhancement (LGE) cardiovascular magnetic resonance (CMR) would be present in adults with repaired TOF and would be related to adverse markers of outcome. METHOD AND RESULTS: LGE was scored in the right and left ventricles (RV and LV) of 92 adult patients who had undergone TOF repair. RV LGE was seen in all patients at surgical sites located in the outflow tract (99%) or the site of ventricular septal defect patching (98%) and in the inferior RV insertion point (79%) and trabeculated myocardium (24%). LV LGE (53%) was located at the apex consistent with apical vent insertion (49%), in the inferior or lateral wall consistent with infarction (5%), or in other areas (8%). Patients with supramedian RV LGE score were older (38 versus 27 years, P<0.001) and more symptomatic (38% versus 8% in New York Heart Association class II or greater, P=0.001), had increased levels of atrial natriuretic peptide (7.3 versus 4.9 pmol/L, P=0.041), and had a trend to higher brain natriuretic peptide (12.3 versus 7.2 pmol/L, P=0.086), exercise intolerance (maximum VO2 24 versus 28 mL.min(-1).kg(-1), P=0.021), RV dysfunction (RV end-systolic volume 61 versus 55 mL/m2, P=0.018; RV ejection fraction 50% versus 56%, P=0.007), and clinical arrhythmia (26% versus 10%, P=0.039). Non-apical vent LV LGE also correlated with markers of adverse outcome. In a multivariate model, RV LGE remained a predictor of arrhythmia. CONCLUSIONS: RV and LV LGE were common after TOF repair and were related to adverse clinical markers, including ventricular dysfunction, exercise intolerance, and neurohormonal activation. Furthermore, RV LGE was significantly associated with clinical arrhythmia.

Adolescent↗
PubMed2006

Importance of initiation pattern of polymorphic ventricular tachycardia in patients with implantable cardioverter defibrillators.

BACKGROUND: Stored intracardiac electrograms (ICEGs) are helpful in understanding the initiation mechanisms of sustained ventricular arrhythmias and in determining the appropriateness of the therapy delivered by implantable cardioverter defibrillators (ICDs). AIM: We investigated the initiation pattern of sustained polymorphic ventricular tachycardia (PVT) and the features of the therapy delivered by ICDs. METHODS: Sixty-six patients (mean age of 67 +/- 8 years) with 97 stored ICEGs showing PVT were evaluated. Cardiovascular diagnosis included coronary artery disease in 72.7% of the patients. The average left ventricular ejection fraction was 33+/-6%. RESULTS: Nonsudden onset episodes were more common than sudden onset episodes (63 episodes, 65% vs 34 episodes, 35%, P < 0.001). More PVT episodes were required multiple shock delivery if they had nonsudden onset initiation (28.6% vs 23.6%, P < 0.01). The mean shock energy delivered for arrhythmia termination was higher in PVT with nonsudden onset (20 +/- 4 vs 14 +/- 5 J, P < 0.01). CONCLUSIONS: The stored ICEGs demonstrate that PVT is most often preceded by ventricular ectopy. To be reverted, nonsudden onset episodes require higher levels of shock energy and more frequently multiple shock achievements than sudden onset episodes.

Aged↗
PubMed2006

Which strategy should be used for acute ST-elevation myocardial infarction in patients aged more than 75 years?

The optimal management of acute myocardial infarction in elderly people (>or= 75 years) is controversial because elderly patients have been excluded or are under-represented in most acute myocardial infarction trials. Randomized studies show that, also in the elderly, thrombolytic therapy is effective in reducing mortality after acute myocardial infarction but the benefit in terms of mortality, recurrent infarction and stroke is smaller compared to primary percutaneous coronary intervention. Among the available mechanical therapeutic strategies, stenting is found to be superior to balloon angioplasty, whereas the role of drug-eluting stents in this setting still remains to be evaluated. The standard use of intravenous unfractionated heparin is still recommended because of the increased risk of intracranial haemorrhage by a combination of low molecular weight heparin or IIb/IIIa inhibitors and thrombolytic agents. Dedicated randomized clinical trials are needed to establish the best reperfusion therapy for this expanding population, especially in patients admitted to hospitals without percutaneous coronary intervention facilities and in patients developing cardiogenic shock.

Aged↗
PubMed2005

Late gadolinium enhancement cardiovascular magnetic resonance of the systemic right ventricle in adults with previous atrial redirection surgery for transposition of the great arteries.

BACKGROUND: Patients treated for transposition of the great arteries by atrial redirection surgery have a right ventricle (RV) that sustains systemic pressures long term. Late RV dysfunction occurs in these patients; the reasons for this are unclear, but myocardial fibrosis may be important. Myocardial fibrosis can be visualized by late gadolinium enhancement (LGE) cardiovascular magnetic resonance (CMR). We hypothesized that LGE would be present in the systemic RV and relate to adverse clinical features. METHODS AND RESULTS: We performed CMR on 36 consecutive adult patients (mean age, 27 years) after atrial redirection surgery for transposition of the great arteries. Late gadolinium RV enhancement was seen in 22 patients (61%) with various patterns. Patients with RV LGE were older (30 versus 22 years; P<0.001) and had increased RV end-systolic volume index (43 versus 35 mL/m2; P=0.03), decreased RV ejection fraction (57% versus 62%; P=0.02), increased QRS duration (108 versus 97 ms; P=0.01), and increased QT dispersion (93 versus 71 ms; P=0.002). The extent of LGE correlated with age (r=0.59, P<0.001) and QRS duration (r=0.67, P<0.001) and inversely with RV ejection fraction (r=-0.76, P<0.001). The incidence of documented arrhythmia and/or syncope (10 of 36) was significantly higher in the late gadolinium-positive group (9/22 versus 1/14; P=0.03). CONCLUSIONS: LGE CMR suggestive of myocardial fibrosis occurs in the systemic RV of patients after atrial redirection surgery. The extent of LGE correlates with age, ventricular dysfunction, electrophysiological parameters, and clinical events, suggesting prognostic importance that merits further investigation.

Adult↗
PubMed2005

Treatment of unprotected left main coronary artery stenosis in the drug-eluting stent era.

Coronary angiography is often inadequate for estimating the severity of ambiguous left main coronary artery (LMCA) stenoses. Our assessment of these lesions can be improved by the techniques of intravascular ultrasound and fractional flow reserve which provide indices of stenosis severity to enable the prediction of future events and planning of treatment. For patients requiring LMCA revascularization, coronary artery bypass graft (CABG) surgery has been gold standard for decades. However, this technique continues to be limited by factors such as periprocedural mortality, prolonged hospital stay and rehabilitation, and long-term graft patency. LMCA stenosis remains one of the few serious challenges for the interventional cardiologists and, in the bare metal stent era, the long-term results were not sufficient to replace CABG surgery, mainly because of the high restenosis rate. Drug-eluting stents (DES) have dramatically reduced the restenosis rate and early results in small series (approximately 300 patients in total) treated with DES in LMCA have been encouraging, especially for lesions at the ostium and in the left main shaft. Before changes are made in the guidelines for treatment, we must wait for a refinement in the technique and stent design used for bifurcational left main lesion and the results of randomized, specific multicenter studies (SYNTAX trial). It is likely that, for selected patients, LMCA stenosis will be regarded as an indication for PCI.

Angioplasty, Balloon, Coronary↗
PubMed2005

Regional distribution and extent of perfusion abnormalities, and the lung to heart uptake ratios during exercise thallium-201 SPECT imaging in patients with cardiac syndrome X.

BACKGROUND: Cardiac syndrome X is defined as angina-like chest pain with transient ischemic ST-segment changes during exercise and angiographically normal epicardial coronary arteries. Studies with myocardial perfusion imaging in this syndrome have indicated that some patients, but not all, have an abnormality on perfusion scan. However, the impact of these perfusion abnormalities on pulmonary thallium uptake is not clear in this group of patients. OBJECTIVE: To evaluate the regional distribution and extent of perfusion abnormalities, and the lung to heart (L:H) uptake ratios using exercise thallium-201 single-photon emission computed tomography (TI-201 SPECT) in patients with cardiac syndrome X. METHODS: The study group consisted of 31 selected cardiac syndrome X patients with regional perfusion abnormalities during exercise TI-201 SPECT imaging. A control group included 26 healthy subjects with normal coronary angiograms, exercise testing and exercise TI-201 SPECT imaging. Exercise TI-201 SPECT results were analyzed with further estimation of the L:H ratios, number and localization of regional perfusion defects, and their mean extent scores expressed in pixels and in per cent of the left ventricular wall. Twenty-two patients with known coronary artery disease were also included in the analysis of the L:H ratios. RESULTS: Multiple perfusion defects were detected in 13 (42%) patients and perfusion defects of single localization were detected 18 (58%) patients. All patients had reversible perfusion abnormalities: 21 (67.7%) had anterior, 14 (45.2%) had inferior and 12 (38.7%) had lateral localization of perfusion defects. The analysis of the extent of the perfusion defects revealed that the mean scores of the extent of the single regional defects were 38.61+/-43.8 pixels and those of multiregional defects were 106.1+/-55.2 pixels, which corresponded to 6.05+/-1.8% and 16.6+/-5.4% of the left ventricular wall defects, respectively. Patients with cardiac syndrome X had a significantly higher L:H ratio during exercise than the healthy subjects (0.46+/-0.02 versus 0.34+/-0.03, P<0.01). In addition, L:H ratios were found to be higher in patients with multiple perfusion defects (0.50+/-0.02) than in patients who had only anterior (0.45+/-0.08) or inferior (0.43+/-0.02) perfusion defects (P<0.05 for both). There were no statistically significant differences in the rest L:H ratios between the study and control groups. Also, no significant differences were observed in exercise L:H ratios between the cardiac syndrome X patients and the patients with coronary artery disease (0.46+/-0.02 versus 0.49+/-0.03, P>0.05). CONCLUSIONS: The results suggest that multiple perfusion defects in multiple vascular regions are relatively common in cardiac syndrome X patients, with the majority of these patients having at least one abnormal perfusion bed. Patients with this syndrome who have perfusion abnormalities also had significantly higher L:H ratios during exercise than did the control patients. Increased exercise L:H ratios were more prominent in patients with multiple perfusion defects.

Adult↗
PubMed2004

Drug-eluting bioabsorbable magnesium stent.

Current stent technology is based on the use of permanent implants that remain life long in the vessel wall, far beyond the time required for the prosthesis to accomplish its main goals of sealing dissection and preventing wall recoil. With the possibility to implant long vessel segments using antiproliferative drugs to prevent restenosis, the practice of transforming the coronary vessels into stiff tubes with a full metal jacket covering all side branches and being unable to adjust to the long-term wall changes, including wall remodeling with lumen ectasia becomes a serious concern. In this article, we describe the first biodegradable stent based on a magnesium alloy that allows controlled corrosion with release to the vessel wall and the blood stream of a natural body component such as magnesium with beneficial antithrombotic, antiarrhythmic, and antiproliferative properties. We also discuss the animal experiments and the initial clinical applications in 20 patients with implants below the knee, with final results soon to be released, and the plans for the first coronary study. The results of these last two studies will indicate whether the absence of a permanent implant and the antiproliferative properties shown in animals are sufficient to prevent the restenotic process in humans or whether the prosthesis must be modified by adding the biodegradable coating with conventional antiproliferative drugs.

Absorbable Implants↗
PubMed2003

Initiation of monomorphic ventricular tachycardia: electrophysiological, clinical features, and drug therapy in patients with implantable defibrillators.

At least 2 distinct patterns of sustained monomorphic ventricular tachycardia (MVT) have been ascribed during analysis of stored intracardiac electrograms retrieved from implantable cardioverter defibrillators and Holter recordings in patients with ventricular arrhythmia. We aimed to investigate the electrophysiological features of MVT with different initiation patterns in patients with implantable cardioverter defibrillators and to assess whether there is a relationship of the initiation patterns of sustained MVT with clinical characteristics and efficacy of antiarrhythmic therapy. Seventy-four stored intracardiac electrograms in 21 patients (mean age of 68.2 +/- 4.2 years) with MVT were evaluated. Cardiovascular diagnosis included coronary artery disease in 85.7% of the patients. All MVT episodes were classified as those initiating with ventricular premature beats (nonsudden onset MVT) and those without ventricular ectopy preceding tachycardia (sudden onset MVT). There was significant difference in left ventricular ejection fraction between MVTs with different initiation pattern, being the lower in those with nonsudden onset (33.6% +/- 38.4% vs. 38.4 +/- 7.0%, P <.04). Ventricular tachycardia cycle length was shorter in group of MVT with nonsudden onset as compared with sudden onset (338.5% +/- 48.1% vs. 376.8% +/- 57.0%, P <.02). Tachycardia with sudden onset was associated with shorter preceding RR interval than tachycardia with nonsudden onset (821.8 +/- 136.2% vs. 748.7 +/- 107.7%, P <.01). There were no significant differences in the type of antiarrhythmic drug therapy used between groups (P >.05). Monomorphic ventricular tachycardias with nonsudden onset occurred more frequently than with sudden onset, without precipitating RR cycles shortening, are faster in rate, associating with lower ejection fraction. Monomorphic ventricular tachycardias with sudden onset are characterized by preceding shortening of RR intervals, slower cycle length, and less worsening of ejection fraction.

Aged↗
PubMed2003

Evaluation of mitral valve prolapse using newly developed real-time three-dimensional echocardiographic system with real-time volume rendering.

The development of a real-time three-dimensional (RT3D) image acquisition system and direct digital links between ultrasound equipment and the data processing computer facilitate improved 3D image reconstruction. However, at present time, it is hard to promptly display 3D images and is also ineffective for a practical use. The objective of this study was to assess the feasibility of a new transthoracic RT3D echocardiographic system for evaluation of mitral valve prolapse. Eighteen patients with mitral valve prolapse diagnosed by transthoracic two-dimensional (2D) echocardiography and M-mode were examined through this technique (11 male, mean age 42 +/- 17 years). Since visualization of mitral valve from apical four-chamber view was better than that of the parasternal approach, only apical approach was used for mitral valve evaluation. This system is capable of acquiring volumetric data from mechanical scanning of the phased-array transducer (3.5 MHz) as well as displaying the volume rendered images of the structure without storing the image data and reconstruction of the object. The prolapse of leaflet could be seen in 14/ 18 (77%) of patients with mitral valve prolapse based on conventional echocardiography. The newly developed transthoracic RT 3D ultrasound system without a reconstruction process seemed to be a useful noninvasive tool for diagnosis of mitral valve prolapse and detection of prolapsed leaflet or scallop, which is very important for deciding on a reliable surgical technique.

Adult↗
PubMed2003

Reversible myoglobinuric renal failure following rhabdomyolysis as a rare complication of cardioversion.

Reversible myoglobinuric renal failure following rhabdomyolysis that was related to repeated countershocks delivered for the treatment of refractory recurrent VT and VF attacks during acute myocardial infarction is presented in this case report, in which scan with technetium-99m pyrophosphate has been used for in the diagnosis of extensive skeletal muscle damage.

Acute Kidney Injury↗