Bahar Pirat

Three-Dimensional Color Doppler Echocardiography for Direct Measurement of Vena Contracta Area in Mitral Regurgitation: In Vitro Validation and Clinical Experience

OBJECTIVESnOur 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.nnnBACKGROUNDnReal-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.nnnMETHODSnUsing 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).nnnRESULTSnIn 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).nnnCONCLUSIONSnMeasurement 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.

Impaired coronary flow reserve in patients with metabolic syndrome

BACKGROUNDnMetabolic syndrome (MetS) is a strong predictor of cardiovascular events. Coronary flow reserve (CFR), as determined by transthoracic echocardiography, is an indicator of microvascular function. In this study, we sought to determine whether CFR is impaired in patients with MetS without clinical coronary heart disease.nnnMETHODSnThirty-three patients with MetS (mean age, 67+/-8 years) and 35 age- and sex-matched controls were studied prospectively. Transthoracic two-dimensional and Doppler echocardiography was performed on all patients. Baseline and hyperemic (after dipyridamole infusion) coronary flow rates were measured using pulsed Doppler echocardiography. CFR was calculated as the ratio of hyperemic to baseline diastolic peak velocities.nnnRESULTSnThere was no difference with regard to baseline systolic and diastolic coronary flow rates in patients with MetS compared with control subjects (19.9+/-3.1cm/s vs. 19.7+/-2.9cm/s, P>.05; and 27.7+/-4.2cm/s vs. 27.1+/-3.6cm/s, P>.05, respectively). Hyperemic diastolic flow and CFR were significantly lower in patients with MetS than in controls (61.7+/-9.4cm/s vs. 70.2+/-9.2cm/s, P<.0001; and 2.2+/-0.5 vs. 2.6+/-0.4, P=.001, respectively). In a logistic regression analysis that included age, sex, body mass index, hypertension, and dyslipidemia and MetS, MetS was the only predictor of a CFR<2.5 (P=.007, OR=6.1, 95% CI: 1.6-23.3).nnnCONCLUSIONnIn conclusion, CFR is impaired in patients with MetS suggesting that coronary microvascular dysfunction, an early finding of atherosclerosis, is present in this patient population. Metabolic syndrome is associated with a CFR<2.5.

Right ventricular contractile reserve in mitral stenosis: Implications on hemodynamic burden and clinical outcome

BACKGROUNDnWe 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).nnnMETHODSnThirty-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.nnnRESULTSnInotropic 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).nnnCONCLUSIONnRV 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.

Follow-Up of Heart Transplant Recipients with Serial Echocardiographic Coronary Flow Reserve and Dobutamine Stress Echocardiography to Detect Cardiac Allograft Vasculopathy

BACKGROUNDnImplementation 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.nnnMETHODSnA 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.nnnRESULTSnAcute 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%).nnnCONCLUSIONSnCFR 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.

Evaluation of coronary microvascular function in patients with end-stage renal disease, and renal allograft recipients.

BACKGROUNDnApproximately 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.nnnMETHODSnEighty-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.nnnRESULTSnThe 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.nnnCONCLUSIONSnCFR 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.

Coronary microvascular function in patients with isolated systolic and combined systolic/diastolic hypertension.

J Clin Hypertens (Greenwich). 2012;14:871–876. ©2012 Wiley Periodicals, Inc.

Comparison of Tissue Doppler Echocardiography Parameters in Patients With End-Stage Renal Disease and Renal Transplant Recipients

BACKGROUNDnTissue Doppler echocardiography has been introduced as a useful tool to assess systolic myocardial function. In this study we sought to compare patients with end-stage renal disease (ESRD), with renal transplantations and control subjects with regard to tissue Doppler parameters.nnnMETHODSnThirty recipients with functional grafts of overall mean age 36 +/- 7 years included 24 men. An equal number of patients with ESRD of overall mean age 35 +/- 7 years included 20 men. A third cohort was comprised of 20 age- and gender matched control subjects. Tissue Doppler imaging from the septal and lateral mitral annulus of the left ventricle and free wall of the right ventricle was performed from a 4-chamber view.nnnRESULTSnMean systolic and diastolic blood pressures were similar among the groups during imaging. Peak systolic velocity (S wave) at the septal annulus was similar in control subjects and recipients. S waves were significantly lower among ESRD patients compared with recipients (10.3 +/- 2.1 vs 12.0 +/- 2.5 cm/s, P = .04, respectively). Isovolumic contraction velocity of the septum and the right ventricular wall were significantly lower in ESRD patients than recipients or controls: 10.2 +/- 2.6 vs 12.5 +/- 2.8 vs 11.4 +/- 1.8 cm/s for septal wall (P = .008) and 13.9 +/- 3.6 vs 17.9 +/- 5.1 vs 16.8 +/- 5.8, for right ventricle (P = .01).nnnCONCLUSIONnSystolic indices of tissue Doppler echocardiography in recipients demonstrated similar values as control subjects and increased values compared with ESRD patients. These results suggested improvement in systolic myocardial function following renal transplantation.

Treatment-associated change in apelin concentration in patients with hypertension and its relationship with left ventricular diastolic function

Objective: We examined the change in apelin concentration and its relationship with left ventricular diastolic function in patients treated for hypertension. Methods: Ninety treatment-naive patients with newly diagnosed hypertension and 33 age- and sex-matched control subjects were prospectively enrolled. Patients with hypertension were randomized to treatment either with telmisartan 80 mg or amlodipine 10 mg. Apelin concentration was measured and echocardiography was performed at baseline and after 1 month of treatment. Results: The data of 77 patients and 33 controls were analyzed. Mean age, gender, baseline blood pressure, apelin levels, and echocardiographic measurements were similar between the treatment groups (p>0.05 for all). Apelin concentration was significantly lower in patients with hypertension than in controls. There was a significant increase in apelin level after 1 month of treatment in both groups (0.32±0.17 vs. 0.38±0.17 ng/dL in telmisartan group, p=0.009, and 0.27±0.13 vs. 0.34±0.18 ng/dL in amlodipine group, p=0.013). Diastolic function improved significantly in both groups (p<0.05) but was not significantly associated with change in apelin concentration. Conclusion: Apelin concentration increased significantly after 1 month of effective treatment with telmisartan or amlodipine to a similar extent. Change in apelin concentration was not associated with improvement in diastolic function.

T1 Mapping by Cardiac Magnetic Resonance and Multidimensional Speckle-Tracking Strain by Echocardiography for the Detection of Acute Cellular Rejection in Cardiac Allograft Recipients

OBJECTIVESnThe aim of this study was to test the hypothesis that echocardiographic strain imaging, by tracking subtle alterations in myocardial function, and cardiac magnetic resonance T1 mapping, by quantifying tissue properties, are useful and complement each other to detect acute cellular rejection in heart transplant recipients.nnnBACKGROUNDnNoninvasive alternatives to endomyocardial biopsy are highly desirable to monitor acute cellular rejection.nnnMETHODSnSurveillance endomyocardial biopsies, catheterizations, and echocardiograms performed serially according to institutional protocol since transplantation were retrospectively reviewed. Sixteen-segment global longitudinal strain (GLS) and circumferential strain were measured before, during, and after the first rejection and at 2 time points for patients without rejection using Velocity Vector Imaging for the first part of the study. The second part, with cardiac magnetic resonance added to the protocol, served to validate previously derived strain cutoffs, examine the progression of strain over time, and to determine the accuracy of strain and T1 measurements to define acute cellular rejection. All tests were performed withinxa048 h.nnnRESULTSnMedian time to first rejection (16 grade 1 rejection, 15 gradexa0≥2 rejection) was 3 months (interquartile range: 3 to 36 months) in 49 patients. GLS and global circumferential strain worsened significantly during grade 1 rejection andxa0≥2 rejection and were independent predictors of any rejection. In the second part of the study, T1 timexa0≥1,090 ms, extracellular volumexa0≥32%, GLS >-14%, and global circumferential strainxa0≥-24% had 100% sensitivity and 100% negative predictive value to define gradexa0≥2 rejection with 70%, 63%, 55%, and 35% positive predictive values, respectively. The combination of GLS >-16% and T1 timexa0≥1,060 ms defined grade 1 rejection with 91% sensitivity and 92% negative predictive value. After successful treatment, T1 times decreased significantly.nnnCONCLUSIONSnT1 mapping and echocardiographic GLS can serve to guide endomyocardial biopsy selectively.

Head to Head Comparison of Speckle Tracking Strain Echocardiography with Invasive Hemodynamic Assessment for the Detection of Acute Cellular Rejection in Cardiac Allograft Recipients

Introduction Non-invasive alternatives to endomyocardial biopsy (EMB) are highly desirable to monitor acute cellular rejection (ACR). In the present study, we aimed to test the hypothesis that echocardiographic strain quantification, by tracking subtle alterations in myocardial function, is useful and superior to invasive hemodynamic measurements to detect ACR. Materials and Methods All patients underwent serial surveillance EMBs, catheterizations and echocardiography examination according to our institutional protocol. Data from the first rejection episodes were compared with the data obtained after treatment. Patients without rejection during follow-up were also included for comparison. All tests were performed within 48 hours of each other. In addition to standard 2D and Doppler echocardiographic measurements, global longitudinal and circumferential strain (GLS, GCS) were assessed from 16 segments, from digitally stored echocardiograms by using the Velocity Vector Imaging software on Syngo Workplace (Siemens Healthcare GmbH, Erlangen/Germany). Results We observed 16 grade 1R, 14 grade 2R and 1 grade 3R and 18 no rejection. Time to first rejection was 3 months (interquartile range: 3-36). Only GLS and GCS were significantly reduced during grade 1R. During grade ≥2R, GLS, GCS, tricuspid annular peak systolic excursion, cardiac index were significantly reduced, right atrial and systolic pulmonary artery pressures were significantly increased as compared to no rejection. The negative and positive predictive values of the best fit cut-off of GLS (<17%) were 98% and 43% for grade ≥2R, 84% and 70% for any rejection. In the multivariate logistic regression analysis including the most pertinent variables according to univariate analyses, GLS and GCS emerged as independent determinants of any rejection (p=.015 and p=.004, respectively). Despite successful treatment, strain values remained significantly lower than the values of no-rejection group (GLS 17.0% [14.7% - 18.3%] vs 18.9% [16.8% - 22.1%]; p=.006, GCS 25.5% [22% - 27.8%] vs 29.0% [24.0% - 33.4%]; p=.01). Figure. No caption available. Conclusions Echocardiographic strain, but not hemodynamic assessment by cardiac catheterization, is a sensitive tool to detect first rejection episode after HTx. However, incomplete normalization of strain after treatment necessitate intra-individual comparisons on serial follow-up are warranted. Strain is a promising marker of ACR however it needs to be tested in larger series.