Bahar Pirat

Baskent University, Engüri, Ankara, Turkey

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Publications (50)181.17 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Velocity vector imaging allows quantitation of myocardial strain and strain rate from 2-dimensional images based on speckle tracking echocardiography. The aim of this study was to analyze the changes in myocardial strain and strain rate patterns in patients with end-stage renal disease and renal transplant recipients. We studied 33 patients with end-stage renal disease on hemodialysis (19 men; mean age, 36 ± 8 y), 24 renal transplant recipients with functional grafts (21 men; mean age, 36 ± 7 y) and 26 age- and sex-matched control subjects. Longitudinal peak systolic strain and strain rate for basal, mid, and apical segments of the left ventricular wall were determined by velocity vector imaging from apical 4- and 2-chamber views. The average longitudinal strain and strain rate for the left ventricle were noted. From short-axis views at the level of papillary muscles, average circumferential, and radial strain, and strain rate were assessed. Mean heart rate and systolic and diastolic blood pressure during imaging were similar between the groups. Longitudinal peak systolic strain and strain rate at basal and mid-segments of the lateral wall were significantly higher in renal transplant recipients and control groups than endstage renal disease patients. Average longitudinal systolic strain from the 4-chamber view was highest in control subjects (-14.5% ± 2.9%) and was higher in renal transplant recipients (-12.5% ± 3.0%) than end-stage renal disease patients (-10.2% ± 1.6%; P ≤ .001). Radial and circumferential strain and strain rate at the level of the papillary muscle were lower in patients with end-stage renal disease than other groups. Differences in myocardial function in patients with end-stage renal disease, renal transplant recipients, and normal controls can be quantified by strain imaging. Myocardial function is improved in renal transplant recipients compared with end-stage renal disease patients.
    04/2015; 13(Suppl 1):235-241.
  • M Türker · A Pirat · A Firat · B Pirat · A Sezgin · G Arslan
    Critical Care 01/2015; 19(Suppl 1):P138. DOI:10.1186/cc14218 · 5.04 Impact Factor
  • European Heart Journal – Cardiovascular Imaging 12/2014; 15(suppl 2):ii78-ii81. DOI:10.1093/ehjci/jeu254 · 4.11 Impact Factor
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    ABSTRACT: Background: Recent studies have demonstrated that longitudinal septal deformation in patients with left ventricular (LV) dysfunction and left bundle branch block (LBBB) predict LV remodeling after CRT. However, the importance of septal deformation patterns for prediction of long-term survival is unknown. Methods: From 2 centers a total of 193 CRT candidates with LBBB (NYHA II-IV, EF≤35, and QRS≥120ms) underwent echocardiography before CRT. Longitudinal 2-D strain analysis in the apical four-chamber view identified four patterns based on previously defined criteria: double-peaked systolic pattern (type 1), early pre-ejection shortening peak followed by prominent systolic stretch (type 2), shortening with one systolic peak inside 70% of ejection phase (type 3) and normal septal peak timing outside early 70% (type 4) . Outcome was pre-defined as freedom from death, left ventricular assist device or heart transplantation over 4 years. Results: Thirty-six patients (19%) had early septal deformation pattern type 1, 49(25%) type 2, 44(23%) type 3 and 64(33%) pseudonormal septal contraction type 4. There were 35 deaths, 4 transplantations, and 6 left ventricular assist device implantations over 4 years. The event rate was 0.05% (2/36) for type 1, 14% (7/49) for type 2, 25% (11/44) for type 3, 39% (25/64) for type 4. Patients with type 1 and 2 patterns had a more favourable event-free survival HR 0.26, CI 0.09-0.81 (P=0.005) than type 3 HR 1.17, CI 0.06-2.2 (P=0.65). Patients with type 4 septal contraction showed poor event-free survival HR 2.8, CI 1.6-5.1 (<0.001). (Figure 1) Conclusions: In LBBB-patients, septal deformation strain patterns predict long-term survival after CRT. Pattern 1 and 2 are highly associated with long-term survival while patients with pattern 4 have a poor prognosis.
    European Heart Journal – Cardiovascular Imaging 12/2014; 15(suppl 2):ii161-ii164. DOI:10.1093/ehjci/jeu264 · 2.65 Impact Factor
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    ABSTRACT: Background Implementation of reliable noninvasive testing for screening cardiac allograft vasculopathy (CAV) is of critical importance. The most widely used modality, dobutamine stress echocardiography (DSE), has moderate sensitivity and specificity. The aim of this study was to assess the potential role of serial coronary flow reserve (CFR) assessment together with DSE for predicting CAV. Methods A total of 90 studies were performed prospectively over 5 years in 23 consecutive heart transplant recipients who survived >1 year after transplantation. Assessment of CFR with transthoracic Doppler echocardiography, DSE, coronary angiography, and endomyocardial biopsy was performed annually. Results of CFR assessment and DSE were compared with angiographic findings of CAV. Results Acute cellular rejections were excluded by endomyocardial biopsies. CAV was detected in 17 of 90 angiograms. Mean CFR was similarly lower in both mild (CAV grade 1) and more severe (CAV grades 2 and 3) vasculopathy, but wall motion score index became higher in parallel with increasing grades of vasculopathy. Any CAV by angiography was detected either simultaneously with or later than CFR impairment, yielding 100% sensitivity for CFR. The combination of CFR and DSE increased the specificity of the latter from 64.3% to 87.2% without compromising sensitivity (77.8%). Conclusions CFR is very sensitive for detecting CAV and increases the diagnostic accuracy of DSE, raising the potential for patient management tailored to risk modification and to avoid unnecessary angiographic procedures.
    Journal of the American Society of Echocardiography: official publication of the American Society of Echocardiography 05/2014; 27(5). DOI:10.1016/j.echo.2014.01.020 · 3.99 Impact Factor
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    ABSTRACT: Migraine is a common neurovascular disorder characterized by attacks of severe headache, autonomic and neurologic symptoms. Migraine can affect many systems in the body, yet its effects on cardiovascular system are unclear. We hypothesized that migraine and coronary microvascular angina may be manifestations of a common systemic microvascular dysfunction and clinically associated. Forty patients with migraine and 35 healthy volunteers were included into the study. Using transthoracic Doppler echocardiography, coronary flow was visualized in the middle or distal part of the left anterior descending artery. Coronary diastolic peak flow velocities were measured with pulse wave Doppler at baseline and after dipyridamole infusion (0.56 mg/kg/4 min). Coronary flow reserve of <2 was considered normal. In addition, thorough 2-dimensional and Doppler echocardiographic examinations were also performed. Fifty-two women and 23 men were included. Coronary flow reserve was significantly lesser in the migraine group than in the control group (1.99 ± 0.3 vs 2.90 ± 0.5, p <0.05). In addition, mitral annular velocities were lower and the ratio of early mitral inflow velocity to early mitral annular velocity (E/E' lateral and E/E' septal) was higher in migraineurs than in the control group (p <0.05 for all), indicating diastolic function abnormalities in the migraine group. In conclusion, these findings suggest that there is an association between coronary microvascular dysfunction and migraine independently of the metabolic state of the patients. A common pathophysiologic pathway of impaired endothelial vasodilatation, vasomotor dysfunction, and increased systemic inflammatory factors may play a role in these 2 clinical conditions and could be the underlying cause of subclinical systolic and diastolic left ventricular dysfunction in migraineurs.
    The American journal of cardiology 08/2013; 112(10). DOI:10.1016/j.amjcard.2013.06.029 · 3.43 Impact Factor
  • Hellenic journal of cardiology: HJC = Hellēnikē kardiologikē epitheōrēsē 03/2013; 54(4):316-7. DOI:10.1016/S0167-5273(13)70007-X · 0.79 Impact Factor
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    International Journal of Cardiology 03/2013; 163(3):S15. DOI:10.1016/S0167-5273(13)70036-6 · 6.18 Impact Factor
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    ABSTRACT: J Clin Hypertens (Greenwich). 2012;14:871-876. ©2012 Wiley Periodicals, Inc. Isolated systolic hypertension (ISH) is a common condition in the elderly that is associated with endothelial dysfunction. Concerning the effect of type of hypertension on coronary microvascular function, coronary flow reserve (CFR) in patients with ISH was evaluated and the results were compared with patients with combined systolic/diastolic hypertension (SDH). Seventy-six elderly patients (older than 60 years) who were free of coronary artery disease and diabetes mellitus were enrolled in the study (38 with ISH and 38 with combined SDH). Using transthoracic Doppler echocardiography, CFR was calculated as the ratio of hyperemic to baseline diastolic peak flow velocities. A CFR value of >2 was accepted as normal. The mean age was 68.6±6.3 years and the groups had similar features with regard to demographic and clinical characteristics. Patients with ISH had significantly lower CFR values compared with those with combined SDH (2.22±0.51 vs 2.49±0.56, respectively; P=.03). On multivariate regression analysis, ISH (β=-0.40, P=.004) and dyslipidemia (β=-0.29, P=.04) were the independent predictors of CFR. These findings indicate that CFR, an indicator of coronary microvascular/endothelial function, is impaired more profoundly in patients with ISH than in patients with combined SDH.
    Journal of Clinical Hypertension 12/2012; 14(12):871-6. DOI:10.1111/j.1751-7176.2012.00705.x · 2.96 Impact Factor
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    ABSTRACT: Although group A β-hemolytic streptococcus is an uncommon cause of infective endocarditis, an increase in the incidence of invasive group A streptococcus infections including bacteremia has been reported in the last two decades. Herein we report Streptococcus pyogenes endocarditis in a previously healthy adult patient who was hospitalized to investigate the etiology of fever. Because of a suspicion of a new vegetation appeared in the second (aortic) valve in the 14(th) day of high dose penicillin G treatment, the mitral and aortic valves were replaced by mechanical prosthesis on the 22(nd) day of treatment. He was discharged from hospital after the 6 week course of antibiotic treatment.
    Balkan Journal of Medical Genetics 09/2012; 29(3):331-3. DOI:10.5152/balkanmedj.2012.053 · 0.17 Impact Factor
  • International Journal of Cardiology 03/2011; 147. DOI:10.1016/S0167-5273(11)70441-7 · 6.18 Impact Factor
  • International Journal of Cardiology 04/2010; 140. DOI:10.1016/S0167-5273(10)70104-2 · 6.18 Impact Factor
  • International Journal of Cardiology 04/2010; 140. DOI:10.1016/S0167-5273(10)70105-4 · 6.18 Impact Factor
  • Scandinavian cardiovascular journal: SCJ 03/2009; 43(1):80. · 1.10 Impact Factor
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    ABSTRACT: The proximal isovelocity surface area (PISA) method is useful in the quantitation of aortic regurgitation (AR). We hypothesized that actual measurement of PISA provided with real-time 3-dimensional (3D) color Doppler yields more accurate regurgitant volumes than those estimated by 2-dimensional (2D) color Doppler PISA. We developed a pulsatile flow model for AR with an imaging chamber in which interchangeable regurgitant orifices with defined shapes and areas were incorporated. An ultrasonic flow meter was used to calculate the reference regurgitant volumes. A total of 29 different flow conditions for 5 orifices with different shapes were tested at a rate of 72 beats/min. 2D PISA was calculated as 2pi r(2), and 3D PISA was measured from 8 equidistant radial planes of the 3D PISA. Regurgitant volume was derived as PISA x aliasing velocity x time velocity integral of AR/peak AR velocity. Regurgitant volumes by flow meter ranged between 12.6 and 30.6 mL/beat (mean 21.4 +/- 5.5 mL/beat). Regurgitant volumes estimated by 2D PISA correlated well with volumes measured by flow meter (r = 0.69); however, a significant underestimation was observed (y = 0.5x + 0.6). Correlation with flow meter volumes was stronger for 3D PISA-derived regurgitant volumes (r = 0.83); significantly less underestimation of regurgitant volumes was seen, with a regression line close to identity (y = 0.9x + 3.9). Direct measurement of PISA is feasible, without geometric assumptions, using real-time 3D color Doppler. Calculation of aortic regurgitant volumes with 3D color Doppler using this methodology is more accurate than conventional 2D method with hemispheric PISA assumption.
    Journal of the American Society of Echocardiography: official publication of the American Society of Echocardiography 02/2009; 22(3):306-13. DOI:10.1016/j.echo.2008.11.031 · 3.99 Impact Factor
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    ABSTRACT: Our goal was to prospectively compare the accuracy of real-time three-dimensional (3D) color Doppler vena contracta (VC) area and two-dimensional (2D) VC diameter in an in vitro model and in the clinical assessment of mitral regurgitation (MR) severity. Real-time 3D color Doppler allows direct measurement of VC area and may be more accurate for assessment of MR than the conventional VC diameter measurement by 2D color Doppler. Using a circulatory loop with an incorporated imaging chamber, various pulsatile flow rates of MR were driven through 4 differently sized orifices. In a clinical study of patients with at least mild MR, regurgitation severity was assessed quantitatively using Doppler-derived effective regurgitant orifice area (EROA), and semiquantitatively as recommended by the American Society of Echocardiography. We describe a step-by-step process to accurately identify the 3D-VC area and compare that measure against known orifice areas (in vitro study) and EROA (clinical study). In vitro, 3D-VC area demonstrated the strongest correlation with known orifice area (r = 0.92, p < 0.001), whereas 2D-VC diameter had a weak correlation with orifice area (r = 0.56, p = 0.01). In a clinical study of 61 patients, 3D-VC area correlated with Doppler-derived EROA (r = 0.85, p < 0.001); the relation was stronger than for 2D-VC diameter (r = 0.67, p < 0.001). The advantage of 3D-VC area over 2D-VC diameter was more pronounced in eccentric jets (r = 0.87, p < 0.001 vs. r = 0.6, p < 0.001, respectively) and in moderate-to-severe or severe MR (r = 0.80, p < 0.001 vs. r = 0.18, p = 0.4, respectively). Measurement of VC area is feasible with real-time 3D color Doppler and provides a simple parameter that accurately reflects MR severity, particularly in eccentric and clinically significant MR where geometric assumptions may be challenging.
    JACC. Cardiovascular imaging 12/2008; 1(6):695-704. DOI:10.1016/j.jcmg.2008.05.014 · 6.99 Impact Factor
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    ABSTRACT: A growing body of data indicates an independent association between serum gamma-glutamyltransferase (GGT) activity, a marker of increased oxidative stress, and cardiovascular diseases. The process of calcific aortic valve disease has been shown to present characteristics of atherosclerosis. The study aim was to evaluate the possible role of serum GGT in patients with calcific aortic valve disease. The results of patients' echocardiography studies from 2005 for the presence of calcific aortic valve disease in the forms of aortic stenosis (AS) and aortic valve calcification (AVC) without significant valve stenosis, were retrospectively evaluated. Age-and gender-matched patients with normal aortic valve morphology were selected at random as a control group. A total of 383 patients was enrolled into the study (126 with AS, 133 with AVC, 124 controls). Serum GGT activity, along with other liver enzyme analyses and laboratory results, were determined and compared among the groups. Age, gender and clinical and laboratory results were similar among the three groups. Median serum GGT levels in the AS, AVC and control groups were 23.0 U/1 (mean 31.5 +/- 24.9 U/1), 22.0 U/1 (mean 27.6 +/- 18.6 U/) and 18.0 U/l (mean 22.4 +/- 16.4 U/l), respectively. Compared to controls, AS patients had significantly higher serum GGT and C-reactive protein levels, while the differences between AVC patients and controls for these parameters were not significant. The study results suggest that serum GGT activity is increased in patients with calcific AS. These increases seem to occur in advanced rather than milder forms of calcific aortic valve disease.
    The Journal of heart valve disease 08/2008; 17(4):371-5. DOI:10.1016/S1567-5688(07)71846-9 · 0.73 Impact Factor
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    ABSTRACT: We investigated whether isovolumic acceleration (IVA) under inotropic stimulation as a means of right ventricular (RV) contractile reserve, is a surrogate for hemodynamic burden and has prognostic value in patients with mitral stenosis (MS). Thirty-one pure MS patients and 20 controls underwent cardiac catheterization, exercise test, and dobutamine stress echocardiography. RV fractional area change (FAC), +dP/dt/P(max), RV tissue Doppler indices (isovolumic contraction [IVC] and systolic [S] velocity, and IVA) were measured. Patients were followed-up for the occurrence of cardiac adverse events. Inotropic modulation unmasked statistically significant differences regarding magnitude of changes in IVA, IVC, S, and +dP/dt/P(max), but not RV FAC. Inability to increase IVA more than 6.5 m/s(2) was the only independent determinant of pulmonary capillary wedge pressure >or=18 mm Hg (P=.004). Although MS severity did not predict the RV contractile reserve and pulmonary artery pressure (PAP) behavior during inotropic stimulation, the RV contractile reserve was related to the degree of systolic PAP. IVA increases of <3.4 m/s(2) had 86% sensitivity and 75% specificity to predict unfavorable outcomes during long-term follow-up (20+/-8 months). RV contractile reserve provides complementary data to the hemodynamic significance of MS severity, may contribute to clinical decision making, and be of prognostic value in these patients.
    International journal of cardiology 07/2008; 135(2):193-201. DOI:10.1016/j.ijcard.2008.03.050 · 6.18 Impact Factor
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    ABSTRACT: Approximately half of all deaths in patients with end-stage renal disease (ESRD) are due to cardiovascular diseases. Although renal transplant improves survival and quality of life in these patients, cardiovascular events significantly affect survival. We sought to evaluate coronary flow reserve (CFR), an indicator of coronary microvascular function, in patients with ESRD and in patients with a functioning kidney graft. Eighty-six patients (30 with ESRD, 30 with a functioning renal allograft, and 26 controls) free of coronary artery disease or diabetes mellitus were included. Transthoracic Doppler echocardiography was used to measure coronary peak flow velocities at baseline and after dipyridamole infusion. CFR was calculated as the ratio of hyperemic to baseline diastolic peak flow velocities and was compared among the groups. The mean age of the study population was 36.1+/-7.3 years. No between-group differences were found regarding age, sex, or prevalences of traditional coronary risk factors other than hypertension. Compared with the renal transplant and control groups, the ESRD group had significantly lower mean CFR values. On multivariate regression analysis, serum levels of creatinine, age, and diastolic dysfunction were independent predictors of CFR. CFR is impaired in patients with ESRD suggesting that coronary microvascular dysfunction, an early finding of atherosclerosis, is evident in these patients. Although associated with a decreased CFR compared with controls, renal transplant on the other hand seems to have a favorable effect on coronary microvascular function.
    Atherosclerosis 06/2008; 202(2):498-504. DOI:10.1016/j.atherosclerosis.2008.04.043 · 3.97 Impact Factor
  • Atherosclerosis Supplements 05/2008; 9(1):147-147. DOI:10.1016/S1567-5688(08)70595-6 · 9.67 Impact Factor