Assessment of Coronary Flow Velocity Reserve by Noninvasive Transthoracic Doppler Echocardiography in Patients with Angiographically Normal Coronary Arteries

Summary： The measurement of coronary flow velocity reserve （CFVR） by transthoracic Doppler echocardiography （TTDE） with invasive intracoronary Doppler flow wire technique （ICD） was validated and the pathological factors which influence CFVR in patients with angiographically normal coronary arteries were analyzed. CFVR was determined successfully in left anterior descending artery （LAD） in 37 of 40 patients with angiographically normal coronary arteries （men 22, women 15, age 20-75 years, mean age 54±12 years）. Coronary flow velocity was measured in the distal LAD by TTDE with contrast enhancement at baseline and during intravenous adenosine infusion of 110 μg/ kg per min within 48 h after ICD technique. Average peak velocity at baseline （APVb）, average peak velocity during hyperemia （APVh） and CFVR determined from TTDE were correlated closely with those from ICD measurements （APVb： y= 0. 64x＋ 5. 04, r=0. 86, P〈0. 001; APVh： y=0. 63x＋14. 36, r=0.82, P〈0.001; CFVR： y=0.65xq-0.92, r=0.88, P〈0.001）. For CFVR measurements, the mean differences between TTDE and ICD methods were 0. 12±0.39. CFVR in patients with history of hypertension was significantly lower than that in patients without history of hypertension （P〈0.05）. Intravascular ultrasound （IVUS） was performed in 34 patients. Plaque formation was found in LAD by IVUS in 17 （50%） patients. No significant difference in CFVR was found between the patients without plaque formation （3. 11±0. 49） and those with plaque formation （2. 76±0.53, P=0. 056）. It is suggested that TTDE with contrast enhancement provides reliable measurement of APV and CFVR in the distal I.AD. The early stage of atherosclerosis could be detected by IVUS, which may be normal in angiography. CFVR is impaired in patients with history of hypertension compared with that in patients without history of hypertension.

Non-invasive Assessment of Coronary Flow Velocity Reserve: A New Method Using Transthoracic Doppler Echocardiography

Summary: Transthoracic Doppler echocardiography (TTDE) allows noninvasive flow measurement in the distal left anterior descending artery (LAD). The feasibility of detecting coronary flow by contrast-enhanced TTDE with second harmonic technique was assessed, the coronary flow velocity reserve (CFVR) was evaluated in comparison to intracoronary Doppler flow (ICD) analysis and the CFVR after PTCA in LAD was investigated. In 77 (96 %) of 80 patients, CFVR was successfully determined with intravenous adenosine infusion. Doppler signal quality was evaluated in the first 46 patients by use of intravenous Levovist infusion and second harmonic technique. The Doppler flow was not visible in 1 patient only. CFVR determined from TTDE (2.77±0.65) was correlated closely with those from ICD (2.88±0.78) measurements (y=0.73x+0.67, r=0.87, P<0.001). In conclusion, TTDE is a feasible method and provides reliable data on CFVR which can be used for follow-up after PTCA.

Can transthoracic Doppler echocardiography be used to detect coronary slow flow phenomenon？

Background Coronary slow flow phenomenon （CSFP） is an important, angiographic clinical entity but is lacking non-invasive detecting techniques. This study aimed to elucidate the value of transthoracic Doppler echocardiography （TTDE） in the diagnosis and monitoring of coronary slow flow in left anterior descending （LAD） coronary artery.Methods We consecutively enrolled 27 patients with CSFP in LAD detected by coronary arteriography from August 2009 to April 2010. Thirty-eight patients with angiographically normal coronary flow served as control. Corrected thrombolysis in myocardial infarction （TIMI） frame count （CTFC） was used to document coronary flow velocities. All subjects underwent TTDE within 24 hours after coronary angiography. LAD flow was detected and the coronary diastolic peak velocities （DPV） and diastolic mean velocities （DMV） were calculated.Results Sixty of 65 （92.3%） subjects successfully underwent TTDE. Baseline clinical characteristics were similar between the two groups. Coronary DPV and DMV of LAD were significantly lower in the CSFP group than in the control group （（0.228±0.029） m/s vs. （0.302±0.065） m/s, P=0.000; （0.176±0.028） m/s vs. （0.226±0.052） m/s, P=0.000,respectively）. There was a high inverse correlation between CTFC and coronary DPV and DMV （r=-0.727, P=0.000;r=-0.671, P=0.000, respectively）. Receiver operating characteristic （ROC） curve showed that the area under the curve （AUC） was less than one half for coronary DPV （AUC=0.104） and DMV （AUC=0.204）, respectively.Conclusions In patients with CSFP, there is a high inverse correlation between CTFC and coronary diastolic flow velocities in the LAD coronary artery, as measured by TTDE. The value of TTDE in the monitoring and evaluation of coronary flow in patients with CSFP deserves further investigation.

Comparison between Doppler echocardiography and hot-film anemometry in measuring the turbulent shear stress downstream of artificial mitral valves： a methodological study

Background Turbulent shear stress （TSS） plays an important role in the research of fluid dynamics of heart valves. This study aimed to perform a quantitative study of TSS downstream of porcine artificial mitral valves in order to verify the correlation of hot-film anemometry （HFA） and Doppler echocardiography combined with computer-aided image analysis for the detection of TSS. Methods A porcine model of mitral valve replacement was established. HFA and Doppler ultrasound techniques were used to directly and indirectly measure TSS-relevant parameters of the artificial mitral valve following different mitral valve replacements： different approaches were used to reserve the subvalvular apparatus of the mitral valve. A correlation analysis was then carried out. Results There was a significant correlation between the HFA and Doppler ultrasound combined with computer-aided image analysis of the TSS at the same time and at the same site. No significant difference was found in the TSS measured by the two methods. Conclusions Compared with HFA, Doppler echocardiography combined with computer-aided image analysis is a safe, non-invasive, and real-time method that enables accurate and quantitative detection of TSS downstream in vivo, objectively reflecting the flow field downstream of the artificial mitral valve. Doppler ultrasound combined with computer- aided image analysis can be employed for quantitatively evaluating the downstream hemodynamic performance of the mitral valve.

Role of 2-dimensional Doppler echo-cardiography in screening portopulmonary hypertension in portal hypertension patients

BACKGROUND: Portopulmonary hypertension (PPH) is difficult to recognize in the early and middle stages because it is frequently asymptomatic. As right ventricular function is impaired in patients with moderate and severe PPH, any dramatic hemodynamic changes in liver transplantation or other procedures may result in death from pulmonary and cardiac events. In this study, we investigated the prevalence of PPH in patients with portal hypertension (PHT) mainly caused by hepatitis B virus, and evaluated the effect of 2-dimensional Doppler echocardiography (2D-ECHO) in screening for PPH. METHODS: One hundred and five PHT patients received transthoracic 2D-ECHO preoperatively, systolic pulmonary arterial pressure (SPAP, normal range <30 mmHg) and pulmonary acceleration time (PAT, normal range >= 120 msec) were measured to screen for PPH (positive result: SPAP >= 30 mmHg and/or PAT <100 msec). Subsequently, pulmonary hemodynamic parameters were measured by right heart catheterization (RHC) for definitive diagnosis of PPH. The results of the two methods were compared to assess the screening effect of 2D-ECHO. RESULTS: The prevalence of PPH in this study was 3.8% (4/105). About 90% (95/105) of patients had a detectable tricuspid regurgitation by 2D-ECHO and the mean SPAP was 27.7 +/- 5.9 mmHg. Twenty-two of these 95 patients had an SPAP >30 mmHg. The mean PAT of all patients was 140 23 msec and 5 were <100 msec. Twenty-two patients were screened out by 2D-ECHO and 4 were diagnosed by RHC. A positive significant correlation (r=0.55, P<0.01) was found between SPAP measured by 2D-ECHO and mean pulmonary artery pressure (MPAP) measured by RHC, and a weak but significant negative correlation (r=-0.27, P=0.005) existed between PAT and pulmonary vascular resistance (PVR). The sensitivity, specificity, agreement rate, positive predictive value and negative predictive value of the screening test were 100%, 82%, 83%, 18% and 100%, respectively. CONCLUSIONS: The prevalence of PPH in this study is lower than in Western countries. As a screening test, 2D-ECHO has very high sensitivity and negative predictive value. A negative test result can directly be used to exclude PPH, while a positive result should be confirmed by RHC.

Correction of Left Ventricular Doppler Echocardiographic Measurements for Physiological Variances Using a Novel Optimized Multivariable Allometric Model in Healthy Chinese Han Adults

Most left ventricular(LV)Doppler measurements vary significantly with age and gender,making it necessary to correct them for physiological variances.We aimed to verify the hypothesis that different Doppler measurements correlate nonlinearly with different biometric variables raised to different scaling factors and exponents.In this work,a total of 23 LV Doppler parameters were measured in 1224 healthy Chinese adults.An optimized multivariable allometric model(OMAM)and scaling equations were developed in 70%of the subjects(group A),and the reliability of the model and equations was verified using the remaining 30%of the subjects(group B)as well as 183 overweight subjects(group C).The single-variable isometric model(SVIM)with body surface area(BSA)as a scaling variable was used for comparison.Before correction,all 23 LV Doppler parameters correlated significantly with one or more of the biometric variables.In group B,gender differences were found in 47.8%(11/23)of the parameters and were eliminated in 81.8%(9/11)of the parameters after correction with OMAM.The successful correction rate with OMAM was 100%(23/23)in group B and 82.6%(19/23)in group C.New reference values for corrected Doppler measurements independent of biometric variables were established.The SVIM with BSA successfully corrected none of the 23 parameters.In conclusion,different LV Doppler parameters allometrically correlated with one or more of the biometric variables.The novel OMAM developed in this study successfully corrected the effects of the physiological variances of most biometric variables on Doppler measurements in healthy and overweight subjects,and was found to be far superior to the SVIM.However,whether the OMAM equations can be applied to other ethnicities,obese subjects,and pathological conditions requires further investigation.

Assessment of atrial electromechanical interval using echocardiography after catheter ablation in patients with persistent atrial fibrillation

We sought to investigate variation of atrial electromechanical interval after catheter ablation procedure in patients with persistent atrial fibrillation using pulse Doppler（PW） and pulse tissue Doppler imaging（PW-TDI）.A total of 25 consecutive in-patients with persistent atrial fibrillation,who restored sinus rhythm after ablation procedure,were recruited in our cardiac center.Echocardiography was performed on each patient at 2 hours,1 day,5 days,1 month and 3 months after the ablation therapy,and atrial electromechanical delay was measured simultaneously by PW and PW-TDI.There was no significant difference between PW and TDI in measuring atrial electromechanical delay.However,at postoperative 2 hours,peak A detection rates were mathematically but nonsignificantly greater by PWTDI than by PW.Second,there was a significant decreasing trend in atrial electromechanical interval from postoperative 2 hours to 3 months,but only postoperative 2-hour atrial electromechanical interval was significantly greater than atrial electromechanical interval at other time.Lastly,patients without postoperative 2-hour atrial electromechanical interval had a significantly longer duration of atrial fibrillation as compared to those with postoperative 2-hour atrial electromechanical interval,by the PW or by PW-TDI,respectively.In patients with persistent atrial fibrillation,atrial electromechanical interval may decrease significantly within the first 24 hours after ablation but remain consistent later,and was significantly related to patients＇ duration of atrial fibrillation.Atrial electromechanical interval,as a potential predicted factor,is recommended to be measured by either PW or TDI after24 hours,when patients had recovered sinus rhythm by radiofrequency ablation.

Pulsed Doppler Tissue Imaging for Assessment of Left Ventricular Systolic and Diastolic Synchronicity in Normal Subjects

Objectives To quantitatively analyze the longitudinal myocardial systolic and diastolic velocities and time intervals of the left ventricle in normal subjects, and to explore the value of pulsed Doppler tissue imaging （DTI） for the assessment of left ventricular systolic and diastolic synchronicity. Methods Twenty and six healthy subjects were studied by pulsed DTI. The septal and lateral, anterior and inferior walls of the left ventricle were displayed respectively, and basal and middle segments of each wall were selected for myocardial motion spectrum sampling. DTI parameters were： peak systolic myocardial velocity （s）, regional pre-ejection period （PEP）, time to the peak of s wave （Ts）, regional ejection time （ET） ; peak early diastolic velocity （e）, peak late diastolic velocity （a）, e/a ratio, time to the beginning of e wave （QE）, time to the peak of e wave （Te） and regional isovolumic relaxation time （IVRT）. Results The e and e/a were significantly different among basal segments, and s and e/a were significantly different among middle segments, with the highest value in lateral segments and the lowest value in septal segments. The s, e and a were all significantly higher in basal segments than middle segments. None of the systolic time intervals （PEP, Ts and ET） and diastolic time intervals （QE, Te and IVRT） were significantly different among basal segments and middle segments, neither were they when basal segment was compared with middle segment. Conclusions In normal subjects, the longitudinal myocardial systolic and diastolic velocities of the left ventricle are not homogeneous, but the contraction and relaxation are highly synchronized. Pulsed DTI can be used to quantitatively analyze the systolic and diastolic synchronicity of the heart.

Patient selection for transcatheter aortic valve replacement:A combined clinical and multimodality imaging approach

Transcatheter aortic valve replacement(TAVR) has been validated as a new therapy for patients affected by severe symptomatic aortic stenosis who are not eligible for surgical intervention because of major contraindication or high operative risk. Patient selection for TAVR should be based not only on accurate assessment of aortic stenosis morphology, but also on several clinical and functional data. Multi-Imaging modalities should be preferred for assessing the anatomy and the dimensions of the aortic valve and annulus before TAVR. Ultrasounds represent the first line tool in evaluation of this patients giving detailed anatomic description of aortic valve complex and allowing estimating with enough reliability the hemodynamic entity of valvular stenosis. Angiography should be used to assess coronary involvement and plan a revascularization strategy before the implant. Multislice computed tomography play a central role as it can give anatomical details in order to choice the best fitting prosthesis, evaluate the morphology of the access path and detect other relevant comorbidities. Cardiovascular magnetic resonance and positron emission tomography are emergent modality helpful in aortic stenosis evaluation. The aim of this review is to give an overview onTAVR clinical and technical aspects essential for adequate selection.

Anterior Mitral Valve Orifice in a Dog

The patient was admitted to OndokuzMayıs University Animal Hospital Internal Medicine outpatient clinic with complaints of epileptic seizures and hypothyroidism. A description of the patient’s owner is available in the history information. There was no physician information. Bradycardia was found in the electrocardiography of the patient. 2-D, M-Mode, PW, CW and Color doppler examinations were performed. Left-ventricular hypokinetic and mitral and tricuspidal valve movements were observed with limited M-Mode imaging. Anterior mitral orifice of 2 mm width was detected on septal mitral valve by PW doppler and color doppler. With this orifice, the presence of regurgitant jet, which covers LA at a rate of 1/3 and was 3.2 m/sec, together with mitral regurgitation (0.5 m/sec.), was demonstrated. PISA calculations;VFR (mL/s), ERO (mm2) and RVol (mL/pulse) values were calculated as if there were mitral regurgitation and data were obtained for mild-moderate mitral regurgitation. Therefore, no operative treatment of the orifice was recommended. Mitral valve orifice is a rare pathology and this is the first report in canine veterinary practice with degenerative mitral valve disorder. We aimed to underline the possibility of mitral orifice development in degenerative mitral valve disorders, known to present with vegetations and varying degrees of prolapsus, conventionally.

Paradoxical Low Flow Low Gradient Severe Aortic Stenosis—An Under-Recognized Entity

Some patients with severe aortic stenosis (AS), due to restrictive cardiac physiology, paradoxically have relatively low flow and low gradients across stenotic aortic valves despite preserved left ventricular (LV) systolic function. It results in symptoms and reduced quality of life and carries a high mortality. Whilst this form of severe AS, termed paradoxical low flow low gradient (pLFLG), is well reported, patients with this diagnosis experience inappropriate barriers to aortic valve replacement (AVR), the only efficacious treatment. We present the case of an 88-year-old female with 12 months of exertional dyspnoea on a background of hypothyroidism and hypercholesterolemia. Transthoracic echocardiogram (TTE) revealed LV hypertrophy, with a small LV cavity size and reduced stroke volume, yet normal systolic function. A heavily calcified aortic valve was identified with severe aortic stenosis, based on valve area, yet with incongruous mean transvalvular gradient of 25 mmHg (severe ≥ 50 mmHg). Following exclusion of other differential diagnoses, her symptoms were attributed to paradoxical LFLG severe AS. She was however declined definitive transcatheter aortic valve implantation (TAVI) due to her paradoxically low mean aortic gradient. Following further deterioration in her symptoms and supportive quantification of poor exercise performance, she was ultimately re-referred, accepted, and underwent TAVI. Following her AVR, the patient experiences significant improvement in both symptoms and quality of life after only one month. Paradoxical LFLG severe AS remains a well-documented yet under recognized disease. It carries high morbidity and mortality if untreated, yet is significantly less likely to be referred and accepted for intervention. With its prevalence expected to rise with an ageing population, this case serves as a timely reminder for clinicians to address the under recognition of important pathology.

Inaccuracy of doppler echocardiographic estimates of pulmonary artery pressures in adult atrial septal defect patients with pulmonary arterial hypertension

Background While echocardiography has been a pivotal screening test in pulmonary arterial hypertension （PAH）, the presence of structural cardiac defects may affect the ability to reliably predict pulmonary artery pressures （PAPs）. This study sought to evaluate the accuracy of Doppler echocardiography （DE） for estimating PAPs in adult atrial septal defect （ASD） patients with PAH. Methods A prospective study was carried out to compare the echocardiographic assessment of PAP with the same pressures obtained by right heart catheterization （RHC） in adult ASD patients with PAH who underwent simultaneous DE and RHC. Bland-Altman analyses were performed to evaluate the agreement between DE and RHC measurements of PAPs. Results Two hundred and fifty-seven patients were included in the study. A significant overestimation of the systolic pulmonary arterial pressure （sPAP） and mean pulmonary artery pressure （mPAP） was reported by echocardiography compared with those by catheterization （（81.8±26.9） mmHg vs. （72.9±26.9） mmHg, P 〈0.01; （51.9±16.4） mmHg vs. （41.4±17.2） mmHg, P 〈0.01, respectively）. Twenty-one percent （55/257） of the patients had PAH when estimated by echocardiography whereas showed normal results in the subsequent catheterization test. Using Bland-Altman analytic methods, the bias for the echocardiographic assessment of the sPAP was 9.1 mmHg with 95% limits of agreement ranging from -24.4 to 42.6 mmHg. For mPAP measurement, the bias was 10.5 mmHg with 95% limits of agreement ranging from -12.4 to 33.4 mmHg. On multiple linear regression analysis, age, gender, body surface area, ASDs＇ diameter, PVR, diastolic blood pressure, and echocardiographic assessment of right atrial pressure （RAP） explained 68.8% of the total variability in the model （P=0.688, P 〈0.01）. Conclusion Inaccuracy was frequently reported in Doppler echocardiographic assessment of the PAP in adult ASD patients with PAH and was often associated with age, gender, body surface area, ASDs＇ diameter, pulmonary vascular resistance, diastolic blood pressure and echocardiographic estimation of RAP.

Cardiac conductive system excitation maps using intracardiac tissue Doppler imaging

OBJECTIVE: To precisely visualize cardiac anatomic structures and simultaneously depict electro-mechanical events for the purpose of precise underblood intervention. METHODS: Intracardiac high-resolution tissue Doppler imaging was used to map real time myocardial contractions in response to electrical activation within the anatomic structure of the cardiac conductive system using a canine open-chest model. RESULTS: The detailed inner anatomic structure of the cardiac conductive system at different sites (i.e., sino-atrial, atrial wall, atrial-ventricular node and ventricular wall) with the inside onset and propagation of myocardial velocity and acceleration induced by electrical activation was clearly visualized and quantitatively evaluated. CONCLUSION: The simultaneous single modality visualization of the anatomy, function and electrical events of the cardiac conductive system will foster target pacing and precision ablation.

Impact of uncontrolled blood pressure on diagnostic accuracy of coronary flow reserve for detecting significant coronary stenosis in hypertensive patients

Background Impaired coronary flow reserve （CFR） in patients with hypertension may be caused by epicardial coronary stenosis or microvascular dysfunction. Antihypertensive treatment has been shown to improve coronary microvascular dysfunction. The aim of this study was to evaluate the impact of uncontrolled blood pressure （BP） on diagnostic accuracy of CFR for detecting significant coronary stenosis. Methods A total of 98 hypertensive patients scheduled for coronary angiography （CAG） due to chest pain were studied. Of them, 45 patients had uncontrolled BP （defined as the office BP 〉140/90 mmHg （1 mmHg=0.133 kPa） in general hypertensive patients, or ≥130/80 mmHg in hypertensive individuals with diabetes mellitus）, and the remaining 53 patients had well-controlled BP. CFR was measured in the left anterior descending coronary artery （LAD） during adenosine triphosphate-induced hyperemia by non-invasive transthoracic Doppler echocardiography （TTDE） within 48 hours prior to CAG. Significant LAD stenosis was defined as 〉70% luminal narrowing. Diagnostic accuracy of CFR for detecting significant coronary stenosis was analyzed with a receiver operating characteristic analysis. Results CFR was significantly lower in patients with uncontrolled BP than in those with well-controlled BP （2.1±0.6 vs. 2.6±0.9, P〈0.01）. Multivariate linear regression analysis of the study showed that the value of CFR was independently associated with the angiographically determined degree of LAD stenosis （β= -0.445, P 〈0.0001） and the presence of uncontrolled BP （β= -0.272, P=0.014）. With a receiver operating characteristic analysis, CFR 〈2.2 was the optimal cut-off value for detecting LAD stenosis in all hypertensive patients （AUC 0.83, 95% CI 0.75-0.91） with a sensitivity of 75%, a specificity of 78%, and an accuracy of 77%. A significant reduction of diagnostic specificity was observed in patients with uncontrolled BP compared with those with well-controlled BP （67% vs. 93%, P=0.031）. Conclusions CFR measurement by TTDE is valuable in the diagnosis of significant coronary stenosis in hypertensive patients. However, the diagnostic specificity is reduced in patients with uncontrolled BP.

A review of isolated muscular ventricular septal defect

Background Color Doppler echocardiography greatly facilitates the diagnosis of isolated muscular ventricular septal defect with a small shunt.Data sources Original research articles were collected from database,including PubMed and Google scholar.Relevant articles about muscular ventricular septal defect were included.Results The frequency of isolated muscular ventricular septal defect is 5.7%in preterm infants and 1.1-5.3%in term infants.Spontaneous closure in muscular ventricular septal defect occurs with higher frequency and earlier than in perimembranous ventricular septal defect.Approximately 80-90%of isolated muscular ventricular septal defect closes spontaneously by 12 months of age.Midventricular muscular ventricular septal defect is spontaneously closed earlier in the short term,but no site difference is found in the long term.The spontaneous closure mechanism is regarded as aposition of the muscle tissueor fibrous tissue formation in the right ventricular side,but in rare cases involves aneurysm formation of the fibrous tissue.Regarding spontaneous closure of isolated muscular ventricular septal defect diagnosed for the fetus,further studies are needed.Chromosomal microarray analysis of fetuses with isolated muscular ventricular septal defect has revealed that it is not a severe risk factor of chromosomal abnormalities.Conclusions This paper presents a review of the history of the diagnosis and frequency of ventricular septal defect,with discussion of its natural history from the fetal period to after birth in patients with isolated muscular ventricular septal defect.