83 research outputs found
Determination of different forms of aminothiols in red blood cells without washing erythrocytes
Detection and quantification of different aminothiols forms (reduced and total) in biological fluids are important for the investigation of oxidative stress-related diseases and cell homeostasis study. The aim of this study was to optimize a HPLC method in order to determine both reduced and total thiol forms in red blood cells (RBC) at low temperature without washing erythrocytes. Analytical recoveries for total and reduced thiols were 91.6-98.5 and 94.9-98.2% respectively. The relative standard deviations intra-assay for total and reduced thiols were 1.14-3.64 and 0.83-2.3% respectively and the relative standard deviations inter-assay for total and reduced thiols were 1.12-3.54 and 0.84-2.03%, respectively. This method allows specific analysis of the aminothiol state inside the RBC, as a model of intracellular metabolism functioning
Determination of different forms of aminothiols in red blood cells without washing erythrocytes
Detection and quantification of different aminothiols forms (reduced and total) in biological fluids are important for the investigation of oxidative stress-related diseases and cell homeostasis study. The aim of this study was to optimize a HPLC method in order to determine both reduced and total thiol forms in red blood cells (RBC) at low temperature without washing erythrocytes. Analytical recoveries for total and reduced thiols were 91.6-98.5 and 94.9-98.2% respectively. The relative standard deviations intra-assay for total and reduced thiols were 1.14-3.64 and 0.83-2.3% respectively and the relative standard deviations inter-assay for total and reduced thiols were 1.12-3.54 and 0.84-2.03%, respectively. This method allows specific analysis of the aminothiol state inside the RBC, as a model of intracellular metabolism functionin
Identification of responders to cardiac resynchronization therapy by contractile reserve during stress echocardiography
Aims The identification of responders to cardiac resynchronization therapy (CRT) remains a challenge. We assessed the role of dyssynchrony (DYS) and contractile reserve (CR) in identifying CRT responders. Methods and results Sixty-nine patients (55% with ischaemic aetiology) referred for CRT (ejection fraction 35%, New York Heart Association III, and QRS duration 120 ms) underwent baseline evaluation of DYS and dobutamine stress-echo [up to 40 mg/kg/min: CR was defined as a wall motion score index (WMSI) variation 0.20]. CRT responders were identified by clinical and/or echocardiographic [end-systolic volume (ESV) decrease 15%] follow-up criteria. During a median follow-up of 11 months, 46 patients (66%) were classified as clinical responders. Reverse remodelling was found in 34 of the 59 patients (58%) with echocardiographic follow-up. CR was present in 78% of clinical responders (P ? 0.001) and in 69% with reverse remodelling (P ? 0.005). DYS was equally present in the two groups. Reverse remodelling was correlated with rest-stress changes in ESV (r ? 0.439, P ? 0.003) and in WMSI (r ? 0.450, P ? 0.001), but not with DYS. CR (OR ? 6.2, 95% CI ? 1.4-27.6, P ? 0.015) was the best predictor of response to CRT. Conclusion Patients with CR show a favourable clinical and reverse LV remodelling response to CRT. This finding shifts the focus from electrical (dyssynchrony) to the myocardial substrate of functional response
Ventricular-Arterial coupling during dipyridamole stress
Background: The interaction of the heart with the systemic vasculature, termed ventricular-arterial coupling, is a central determinant of net cardiovascular performance in normal and pathological conditions. Ventricular and arterial elastance can be easily assessed by echocardiography, both at rest and during stress. Aim: To assess noninvasively left ventricular-arterial coupling in healthy and diseased subjects at rest and during dipyridamole (DIP) stress. Materials and methods: We enrolled 365 patients (63?16 years; 231 males) referred to stress echo lab: 131 "normals" (Nl); 86 patients with coronary artery disease, 68 with negative (CAD, SE -) and 18 with positive (CAD, SE+) stress echo; 148 with idiopathic dilated cardiomyopathy (DCM). In all, ventricular-arterial coupling was indexed by the ratio of ventricular force (Systolic Pressure/End-Systolic Volume index) to arterial elastance (EaI, ratio of end-systolic pressure by stroke volume). 2D echo (for ESV and stroke volume) and cuff sphygmomanometer (systolic pressure, multiplied x 0.90 to obtain end-systolic pressure) provided the raw measurements. Results: At rest, EaI was profoundly increased in DCM (6.3?4.4; p<.001 vs. all other groups: Nl=4?1.1; CAD, SE-=3.8?1; CAD SE+=4.2?1.3). DIP maximized ventricular-arterial coupling in normals. Residual vasodilatation and contractile reserve slightly increased cardiac efficiency in DCM and in CAD SE- pts. The CAD SE+ pts showed negative contractile reserve and the worse stress ventricular arterial coupling (see figure). Conclusions: Ventricular-arterial coupling was optimized by DIP in normals, and disrupted in CAD patients with stress induced ischemia. Effective arterial elastance is dramatically increased in DCM at rest and weakly responds to vasodilator stress
Identification of responders to CRT by stress echo: no contractile reserve, no party
Background: Cardiac resynchronization therapy (CRT) is increasingly used, but the identification of "responders" remains challenging. Aim: to assess the value of inotropic reserve during pharmacological echo stress to identify responders. Materials and methods: We enrolled 32 patients (age 69?9 years; 9 females) referred to CRT, all with LV ejection fraction (LVEF) ≤35n %, NYHA ≥IIb and QRS duration ≥130 milliseconds. Twenty-two patients showed echocardiographic criteria for dyssynchrony (at least one of M-mode, Tissue Doppler, or live 3D echo criteria). All patients underwent pharmacological stress echo (dobutamine, up to 40 mcg/Kg/min in 29, dipyridamole 0.84 mg/kg 10 min, in 3). Patients were considered with contractile response if variation of WMSI (from 1=normal, to 4=dyskinetic, 17 segment model of left ventricle) stress-rest (delta WMSI) was ≥0.20. "Responders" to CRT were defined at 6 months follow-up as survivors with NYHA class improvement ≥1 grade and without new hospital admission for acute heart failure. Results: In the follow-up (median=20 months), 16 patients were responders to CRT (Group I) and 16 non-responders (Group II). Responders showed a wider QRS (I=162?25 vs. II=142 ?27 msec; p .044) and a greater delta WMSI (I=0.34?0.25 vs. II= 0.15?0.18; p=.021). At individual patient analysis, inotropic reserve was more often associated with a favourable clinical outcome (see figure) whereas dyssynchrony criteria by echocardiography were equally present in the two groups (I=12/16 vs. II=10/16, p=ns). In the follow-up there were 5 deaths, all in group II. Conclusion: Patients with contractile reserve during stress echo show a favourable clinical response to CRT. This parameter shifts the focus from electrical (dyssynchrony) to the myocardial substrate of functional response: no muscle, no party
Live 3-D stress echo: is beauty also a sign of intelligence?
Background: Last generation 3-D live stress echo has potential for adding "beauty" (seductive display) and also "intelligence" (unique quantitative information) to the robust, albeit qualitative, classic 2-D stress echo based on wall motion analysis. Aim: to assess feasibility of 3-D stress echo. Materials and methods: From May 2005, we enrolled 214 consecutive patients (age=64?11 years; 88 females) routinely screened for suspect coronary artery disease with dipyridamole (0.84 mg/kg in 6\u27) stress echo. Transthoracic echocardiography (2D, 3D and coronary flow reserve, CFR, by pulsed Doppler) was performed with commercially available systems (iE33) using phase array probes (1-5 and 3-8 MHz, S5-S8) and a matrix 3D probe for 3D-Live application. Each data set was analyzed with a dedicated software (3DQ, QLab - Advanced Ultrasound Quantification Software - vs. 4.1 and 4.2, Philips Electronics), including 3D volumes and dissynchrony index (DI), considered as the mean value of standard deviation of maximum time to systolic volume variation. Results: Interpretable 2D data were obtained in all pts (100 % feasibility), CFR data on left anterior descending artery in 185 pts (88 %) and 3D data in 151 pts (70 %). In the 48 pts with negative stress echo (for wall motion criteria) by 2D and 3D, 3D-DI decreased (rest=1.3?.8 vs. stress=.99?.54, p<.001): see figure. In patients with normal resting echo and positive stress echo, 3D-DI increased (rest= 4.5?1.9 vs. stress= 8.3?3.2, p<0.01). Last generation live 3D dipyridamole stress echo still suffers a feasibility gap vs. 2D and Doppler-CFR stress echo, but shows potential for adding substantial "beauty" (convincing display) and perhaps some extra-"intelligence" (quantitative support) to classic stress echo
Stress echo 2020: the international stress echo study in ischemic and non-ischemic heart disease
BACKGROUND: Stress echocardiography (SE) has an established role in evidence-based guidelines, but recently its breadth and variety of applications have extended well beyond coronary artery disease (CAD). We lack a prospective research study of SE applications, in and beyond CAD, also considering a variety of signs in addition to regional wall motion abnormalities. METHODS: In a prospective, multicenter, international, observational study design, > 100 certified high-volume SE labs (initially from Italy, Brazil, Hungary, and Serbia) will be networked with an organized system of clinical, laboratory and imaging data collection at the time of physical or pharmacological SE, with structured follow-up information. The study is endorsed by the Italian Society of Cardiovascular Echography and organized in 10 subprojects focusing on: contractile reserve for prediction of cardiac resynchronization or medical therapy response; stress B-lines in heart failure; hypertrophic cardiomyopathy; heart failure with preserved ejection fraction; mitral regurgitation after either transcatheter or surgical aortic valve replacement; outdoor SE in extreme physiology; right ventricular contractile reserve in repaired Tetralogy of Fallot; suspected or initial pulmonary arterial hypertension; coronary flow velocity, left ventricular elastance reserve and B-lines in known or suspected CAD; identification of subclinical familial disease in genotype-positive, phenotype- negative healthy relatives of inherited disease (such as hypertrophic cardiomyopathy). RESULTS: We expect to recruit about 10,000 patients over a 5-year period (2016-2020), with sample sizes ranging from 5,000 for coronary flow velocity/ left ventricular elastance/ B-lines in CAD to around 250 for hypertrophic cardiomyopathy or repaired Tetralogy of Fallot. This data-base will allow to investigate technical questions such as feasibility and reproducibility of various SE parameters and to assess their prognostic value in different clinical scenarios. CONCLUSIONS: The study will create the cultural, informatic and scientific infrastructure connecting high-volume, accredited SE labs, sharing common criteria of indication, execution, reporting and image storage of SE to obtain original safety, feasibility, and outcome data in evidence-poor diagnostic fields, also outside the established core application of SE in CAD based on regional wall motion abnormalities. The study will standardize procedures, validate emerging signs, and integrate the new information with established knowledge, helping to build a next-generation SE lab without inner walls
Feasibility of real-time three-dimensional stress echocardiography: pharmacological and semi-supine exercise
<p>Abstract</p> <p>Background</p> <p>Real time three dimensional (RT3D) echocardiography is an accurate and reproducible method for assessing left ventricular shape and function.</p> <p>Aim</p> <p>assess the feasibility and reproducibility of RT3D stress echocardiography (SE) (exercise and pharmacological) in the evaluation of left ventricular function compared to 2D.</p> <p>Methods and results</p> <p>One hundred eleven patients with known or suspected coronary artery disease underwent 2D and RT3DSE. The agreement in WMSI, EDV, ESV measurements was made off-line.</p> <p>The feasibility of RT-3DSE was 67%. The inter-observer variability for WMSI by RT3D echo was higher during exercise and with suboptimal quality images (good: k = 0.88; bad: k = 0.69); and with high heart rate both for pharmacological (HR < 100 bpm, k = 0.83; HR ≥ 100 bpm, k = 0.49) and exercise SE (HR < 120 bpm, k = 0.88; HR ≥ 120 bpm, k = 0.78). The RT3D reproducibility was high for ESV volumes (0.3 ± 14 ml; CI 95%: -27 to 27 ml; p = n.s.).</p> <p>Conclusions</p> <p>RT3DSE is more vulnerable than 2D due to tachycardia, signal quality, patient decubitus and suboptimal resting image quality, making exercise RT3DSE less attractive than pharmacological stress.</p
Head to head comparison of 2D vs real time 3D dipyridamole stress echocardiography
Real-time three-dimensional (RT-3D) echocardiography has entered the clinical practice but true incremental value over standard two-dimensional echocardiography (2D) remains uncertain when applied to stress echo. The aim of the present study is to establish the additional value of RT-3D stress echo over standard 2D stress echocardiography. We evaluated 23 consecutive patients (age = 65 ± 10 years, 16 men) referred for dipyridamole stress echocardiography with Sonos 7500 (Philips Medical Systems, Palo, Alto, CA) equipped with a phased – array 1.6–2.5 MHz probe with second harmonic capability for 2D imaging and a 2–4 MHz matrix-phased array transducer producing 60 × 70 volumetric pyramidal data containing the entire left ventricle for RT-3D imaging. In all patients, images were digitally stored in 2D and 3D for baseline and peak stress with a delay between acquisitions of less than 60 seconds. Wall motion analysis was interpreted on-line for 2D and off-line for RT-3D by joint reading of two expert stress ecocardiographist. Segmental image quality was scored from 1 = excellent to 5 = uninterpretable. Interpretable images were obtained in all patients. Acquisition time for 2D images was 67 ± 21 sec vs 40 ± 22 sec for RT-3D (p = 0.5). Wall motion analysis time was 2.8 ± 0.5 min for 2D and 13 ± 7 min for 3D (p = 0.0001). Segmental image quality score was 1.4 ± 0.5 for 2D and 2.6 ± 0.7 for 3D (p = 0.0001). Positive test results was found in 5/23 patients. 2D and RT-3D were in agreement in 3 out of these 5 positive exams. Overall stress result (positive vs negative) concordance was 91% (Kappa = 0.80) between 2D and RT-3D. During dipyridamole stress echocardiography RT-3D imaging is highly feasible and shows a high concordance rate with standard 2D stress echo. 2D images take longer time to acquire and RT-3D is more time-consuming to analyze. At present, there is no clear clinical advantage justifying routine RT-3D stress echocardiography use
Arterial pressure changes monitoring with a new precordial noninvasive sensor
<p>Abstract</p> <p>Background</p> <p>Recently, a cutaneous force-frequency relation recording system based on first heart sound amplitude vibrations has been validated. A further application is the assessment of Second Heart Sound (S2) amplitude variations at increasing heart rates. The aim of this study was to assess the relationship between second heart sound amplitude variations at increasing heart rates and hemodynamic changes.</p> <p>Methods</p> <p>The transcutaneous force sensor was positioned in the precordial region in 146 consecutive patients referred for exercise (n = 99), dipyridamole (n = 41), or pacing stress (n = 6). The curve of S2 peak amplitude variation as a function of heart rate was computed as the increment with respect to the resting value.</p> <p>Results</p> <p>A consistent S2 signal was obtained in all patients. Baseline S2 was 7.2 ± 3.3 m<it>g</it>, increasing to 12.7 ± 7.7 m<it>g </it>at peak stress. S2 percentage increase was + 133 ± 104% in the 99 exercise, + 2 ± 22% in the 41 dipyridamole, and + 31 ± 27% in the 6 pacing patients (p < 0.05). Significant determinants of S2 amplitude were blood pressure, heart rate, and cardiac index with best correlation (R = .57) for mean pressure.</p> <p>Conclusion</p> <p>S2 recording quantitatively documents systemic pressure changes.</p
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