Ultrasound tissue characterization by integrated backscatter for analyzing Fluorouracil induced myocardial damage

BACKGROUND: 5-Fluorouracil (5-FU) cardiotoxicity is a well-known clinical phenomenon whose pathophysiology remains controversial. Cyclic variation of integrated backscatter (CVIBS) assesses acoustic properties of myocardium that may reflect both contractility and structural changes. The aim of this study was to evaluate CVIBS alterations in cancer patients under high-dose leucovorin and infusional 5-FU (HDLV5FU) chemotherapy. METHOD: We prospectively evaluated 37 cancer patients under HDLV5FU treatment. Transthoracic echocardiography and CVIBS were performed at the 0th, 48th hours, and on day 15 of the first cycle. The parasternal long-axis view was preferred to obtain the image of integrated backscatter and mainly two regions of interest--interventricular septum (IVS) and posterior wall (PW)--were used. RESULTS: Clinical cardiotoxicity was observed in two patients. No significant differences were detected in pre- and posttreatment conventional echocardiography evaluations. However, both the IVS (9.3 +/- 1.0 to 8.1 +/- 1.2 dB, P < 0.001) and PW (9.1 +/- 0.7 to 7.8 +/- 0.9 dB, P < 0.001) CVIBS values significantly decreased in all patients. All values were returned to pretreatment levels (9.2 +/- 0.9 dB in the CVIBS-IVS and 8.9 +/- 0.6 dB in CVIBS-PW, respectively) on day 15 after the treatments. CONCLUSION: This study suggests that HDLV5FU may cause acute transient alterations in CVIBS values in the absence of clinical symptoms and signs of cardiotoxicity. The clinical value of CVIBS should be further studied in patients receiving 5-FU-based therapy.     

Backscatter directivity and integrated backscatter power of arterial tissue

A 27 MHz transducer, mounted on an ultrasonic microscope, was used to quantify the dependence of backscatter power on the angle of incidence of arterial vessels. Due to variations in the angle of incidence significant variations in backscatter power were found in the intima, the muscular and elastic media, the adventitia and the external elastic lamina. The muscular and the elastic media show anisotropic behaviour in their angle dependence, i.e. the extent of the angle dependence depends on the direction of angle variation. This anisotropic nature is probably caused by the dominant orientation of smooth muscle cells or elastin fibers in these tissue layers.Measurements on 13 specimens of the iliac artery showed that each tissue type of the vessel has its own specific angle dependent behaviour. In the future this property might be used for quantitative tissue characterization.     

Cyclic variation of myocardial integrated backscatter and myocardial wall thickness during percutaneous coronary angioplasty

Cyclic variation of myocardial integrated backscatter (CVIBS) and change in myocardial wall thickness (WT%) were evaluated during percutaneous transluminal coronary angioplasty (PTCA). Fourteen patients who underwent PTCA of the proximal left anterior descending (LAD) coronary artery were included in the study. PTCA was performed by inflating the balloon at the site of the LAD lesion for 1 minute. CVIBS was measured at three episodes during PTCA in the parasternal short-axis view: before the inflation, at the end of 1-minute inflation, and at the fifth-minute after deflation of the balloon. Three regions of interest were used to evaluate the three-vessel territories: mid-anteroseptal area for LAD, mid-posterolateral area for circumflex artery, and mid-inferior area for right coronary artery. The WT% was calculated in each area. In the LAD territory, CVIBS measured at the end of 1-minute inflation was lower than the values obtained before PTCA, 5.2 +/- 1.0 decibel (dB) versus 3.7 +/- 0.7 dB (P < 0.01). CVIBS magnitudes increased at the fifth-minute after the deflation back up even to higher levels than pre-PTCA values,6.1 +/- 1.0 dB versus 5.2 +/- 1.0 dB (P < 0.01). The WT% values decreased during balloon inflation but did not recover to the pre-inflation values measured at fifth-minute after deflation. In other sites, there was no change in either CVIBS or WT% values at any time studied. The observed increase in CVIBS may be an indicator of restoration of blood flow to ischemic myocardium.     

Ultrasonic tissue characterization and Doppler tissue imaging in the analysis of left ventricular function in essential arterial hypertension: a preliminary study

It is not known if diastolic abnormalities are independent of systolic dysfunction in arterial hypertension. We studied three groups of 10 male subjects of comparable mean age (31.6 +/- 3.5 years), weight, and height: Athletes (A) (cyclists), essential hypertensive patients (H), and controls (C). Ultrasonic myocardial integrated backscatter signals (IBS) of the septum and the posterior wall were analyzed, while the systo-diastolic variation of the backscatter was considered as a cyclic variation index (CVI(ibs)). Myocardial velocities across the left ventricular major axis were sampled at septum and lateral wall levels by pulsed-wave Doppler tissue imaging (DTI). CVI(ibs) at the septum and the posterior wall were significantly lower in the hypertensive group in comparison with athletes and controls, who were comparable. Early diastolic myocardial velocity (E(m)) of the lateral wall and of the septum were significantly lower in hypertensives, while the late diastolic myocardial velocity (A(m)) was significantly higher in hypertensives in comparison with athletes. The E(m)/A(m) at the septum level was significantly lower in hypertensives in comparison with athletes and controls. Significant correlations were found between CVI and DTI parameters: CVI(ibs) and E(m)/A(m) septum (r = 0.50, P < 0.002). Furthermore, significant correlations were found between mean arterial pressure (MAP) and E(m)/A(m) septum (r = - 0.65, P < 0.001). Ultrasonic tissue characterization with the intrinsic contractility study and the evaluation of the regional diastolic function should, therefore, represent a new integrated diagnostic modality for the evaluation of left ventricular hypertrophied intramyocardial function. This study demonstrated that diastolic abnormalities of left ventricular function, in arterial hypertension, are related and progress with systolic intrinsic dysfunction.     

Ultrasonic Tissue Characterization: Review of a Noninvasive Technique for Assessing Myocardial Viability

The determination of myocardial perfusion and myocardial viability has prognostic and therapeutic implications, particularly in the current era of percutaneous transluminal coronary angioplasty and thrombolytic therapy. Several modes of investigation, including positron emission tomography, thallium-201 scintigraphy, and nuclear magnetic resonance imaging are used to differentiate viable from nonviable myocardium. Though these noninvasive tests are useful diagnostic modalities, they are expensive, time consuming, and too cumbersome to be used in the acute setting. Expeditious distinction between viable and nonviable myocardium, during acute coronary syndromes, is of great importance since reperfusion can minimize the extent ofischemic injury and infarction. An expanding body of evidence confirms that ultrasonic tissue characterization has great potential to become a practical bedside diagnostic tool in the search for salvageable myocardium. Further clinical investigative studies would help accomplish a better understanding of the complex interaction between ultrasound and myocardium.     

Serum markers of angiogenesis and myocardial ultrasonic tissue characterization in patients with dilated cardiomyopathy

BACKGROUND AND AIMS: It has been proven that a disturbance in angiogenesis contributes to the progression of myocardial interstitial fibrosis in idiopathic dilated cardiomyopathy (DCM). This study was designed to evaluate the relationship between serum activity of angiogenic factors and myocardial ultrasonic tissue characterization in patients with DCM. METHODS AND RESULTS: We studied 30 patients with DCM and 15 healthy control subjects. Serum levels of vascular endothelial growth factor (VEGF), interleukin (IL)-4 and IL-13 were measured using enzyme-linked immunosorbent assay. We determined calibrated myocardial integrated backscatter (IB) as the value of myocardial interstitial fibrosis using ultrasonic tissue characterization and also quantified the magnitude of cyclic variations in IB (CV-IB). Serum levels of VEGF and IL-13 were significantly higher in patients with DCM than in control subjects (both P<0.05). Calibrated IB was significantly higher and CV-IB was markedly lower in patients with DCM than in control subjects (both P<0.01). In patients with DCM, the levels of IL-13 significantly correlated with calibrated IB (r=0.520, P=0.018). In addition, there was a significant negative correlation between levels of VEGF and CV-IB (r=-0.611, P=0.007). CONCLUSION: The increase in serum VEGF and IL-13 may be closely related to alterations in myocardial texture in DCM.     

Pulmonary hypertension and left heart function: insights from tissue Doppler imaging and myocardial performance index

BACKGROUND: As a consequence of a leftward shift of the interventricular septum and of pericardial restraint, related to the degree RV dilatation, left heart function would be influenced after pulmonary hypertension and right heart failure. METHODS AND RESULTS: We enrolled 70 patients with pulmonary artery systolic pressure (PASP) more than 30 mmHg: 40 patients with PASP between 30 and 60 mmHg (Group 2), 30 patients with PASP more than 60 mmHg (Group 3). Another 70 patients with normal heart performance and PASP less than 30 mmHg served as the control group (Group 1). Myocardial performance index (MPI), isovolumic contraction time (IVCT), and isovolumic relaxation time (IVRT) were obtained by tissue Doppler imaging (TDI). PASP correlated negatively to peak systolic velocity of lateral tricuspid annulus (RV-Sm) and RVEF. The MPI of RV and LV in patients with severe pulmonary hypertension (Group 3) became higher as the result of the prolongation of IVRT. The higher E/Em (peak early-diastolic mitral-inflow velocity divided by early-diastolic velocity of mitral annulus) in pulmonary hypertension indicated diastolic dysfunction of LV. The decline of left ventricular ejection fraction, and also right ventricular ejection fraction, suggested LV systolic dysfunction after pulmonary hypertension. The LV-MPI truly reflected LV systolic and diastolic dysfunction in patients with pulmonary hypertension. In multiple linear regression analysis, LV-MPI was independently associated only with RV-MPI (Beta 0.47, P < 0.0001). CONCLUSION: The result infers that the systolic and diastolic function of LV declined, following pulmonary hypertension.     

Ultrasonic characterization of porcine liver tissue at frequency between 25 to 55 MHz

AIM: To study the relation between acoustic parameters and histological structure of biological tissue and to provide the basis for high-resolution image of biological tissues and quantitative ultrasonic diagnosis of liver disease. METHODS: Ultrasonic imaging and tissue characterization of four normal porcine liver and five cirrhotic liver tissue samples were performed using a high frequency imaging system. RESULTS: The acoustic parameters of cirrhotic liver tissue were larger than those of normal liver tissue. The sound velocity was 1577 m/s in normal liver tissue and 1631 m/s in cirrhotic liver tissue. At 35 MHz, the attenuation coefficient was 3.0 dB/mm in normal liver tissue and 4.1 dB/mm in cirrhotic liver tissue. The backscatter coefficient was 0.00431 dB/Srmm in cirrhotic liver tissue and 0.00303 dB/Srmm in normal liver tissue. The backscatter coefficient increased with the frequency. The high frequency images coincided with their histological features. CONCLUSION: The acoustic parameters, especially the sound backscatter coefficient, are sensitive to the changes of liver tissues and can be used to differentiate between the normal and pathological liver tissues. High frequency image system is a useful device for high-resolution image and tissue characterization.     

Use of cyclic variation of integrated backscatter to assess contractile reserve and myocardial viability in chronic ischemic left ventricular dysfunction

The detection of viable myocardium has important implications for management, but use of stress echocardiography to detect this is subjective and requires exposure to dobutamine. We investigated whether cyclic variation (CV) of integrated backscatter (IB) from the apical views could provide a resting study for detection of contractile reserve (CR) and prediction of myocardial viability in 27 patients with chronic ischemic left ventricular (LV) dysfunction. Repeat echocardiography was performed after 6.7 +/- 3.8 months of follow-up; 14 patients underwent revascularization and 13 were treated medically. Using a standardized dobutamine echocardiography (DbE) protocol, images from three apical views were acquired at 80-120 frames/sec at rest and during stress. CR was identified if improvement of wall motion was observed at low dose (5 or 10 microg/kg/min) DbE. Myocardial viability was characterized by improvement at follow-up echocardiography in patients with revascularization. CVIB at rest and low dose dobutamine were assessed in 194 segments with resting asynergy (severe hypokinesis or akinesis), of which 88 (45%) were in patients who underwent revascularization. Of these, CVIB could be measured in 190 (98%) segments at rest and 185 (95%) at low dose dobutamine. Sixty-two (33%) segments had CR during low dose DbE and 50 (57%) segments showed wall-motion recovery (myocardial viability) at follow-up echocardiography. Segments with CR had significantly higher CVIB at rest (P < 0.001) and low dose dobutamine (P = 0.005) than segments without CR. Using optimal thresholds of CVIB (> 8.2 dB) at rest, the accuracy of CVIB for detecting CR was 70%. Compared with nonviable segments, viable segments had significantly higher CVIB at rest (P < 0.001) and low dose dobutamine (P < 0.001). Using optimal thresholds of CVIB (> 5.3 dB) at rest, the accuracy of CVIB for detecting myocardial viability was 85%, which was higher than that in conventional DbE (62%, P < 0.01). Thus, assessment of CVIB from the apical views is a feasible and accurate tool for detecting CR and predicting myocardial viability in chronic LV dysfunction.     

Effect of preload and heart rate on the doppler and tissue doppler-derived myocardial performance index

Doppler-derived myocardial performance index (MPI) has been described as a noninvasive measurement of LV function. Our aim was to investigate the effect of hemodialysis related volume reduction and heart rate changes on the Doppler-derived LV MPI, and Doppler tissue imaging (DTI) derived left and right ventricular MPI. METHOD: The study group comprised 32 consecutive patients (mean age: 43 +/- 18 yrs) undergoing hemodialysis. Patients underwent echocardiography before and immediately after hemodialysis session. Left and right ventricular MPI derived from conventional pulsed-wave Doppler and DTI was calculated. The difference in MPI, heart rate and body weight was calculated before and after hemodialysis. RESULTS: Doppler-derived LV MPI, and right ventricular MPI obtained by DTI were increased (p = 0.05) but the LV MPI obtained by DTI was unchanged after hemodialysis. There is a significant positive correlation between the Doppler-derived LV MPI difference and volume reduction (r = 0.38, p = 0.032). The heart rate difference was correlated with Doppler-derived LV MPI difference, and DTI derived right ventricular MPI difference (r = 0.38, p = 0.034; r = 0.48, p = 0.006, respectively). Whereas, DTI derived LV MPI difference was not correlated with heart rate difference. By the multivariate analysis, there was no correlation between Doppler-derived LV MPI difference with heart rate difference, and volume reduction. Right ventricular MPI difference correlated with heart rate difference (r = 0.41, p = 0.021) but not with volume reduction. Doppler-derived MPI is partially influenced by preload and heart rate changes. However, DTI derived LV MPI is not influenced by preload and heart rate changes.     

Role of smooth muscle activation in the static and dynamic mechanical characterization of human aortas

Experimental data and a suitable material model for human aortas with smooth muscle activation are not available in the literature despite the need for developing advanced grafts; the present study closes this gap. Mechanical characterization of human descending thoracic aortas was performed with and without vascular smooth muscle (VSM) activation. Specimens were taken from 13 heart-beating donors. The aortic segments were cooled in Belzer UW solution during transport and tested within a few hours after explantation. VSM activation was achieved through the use of potassium depolarization and noradrenaline as vasoactive agents. In addition to isometric activation experiments, the quasistatic passive and active stress–strain curves were obtained for circumferential and longitudinal strips of the aortic material. This characterization made it possible to create an original mechanical model of the active aortic material that accurately fits the experimental data. The dynamic mechanical characterization was executed using cyclic strain at different frequencies of physiological interest. An initial prestretch, which corresponded to the physiological conditions, was applied before cyclic loading. Dynamic tests made it possible to identify the differences in the viscoelastic behavior of the passive and active tissue. This work illustrates the importance of VSM activation for the static and dynamic mechanical response of human aortas. Most importantly, this study provides material data and a material model for the development of a future generation of active aortic grafts that mimic natural behavior and help regulate blood pressure.

The rupture of aortic aneurysms causes around 10,000 deaths each year in the United States (1). Surgical repair of aortic aneurysms and aortic dissections absorb significant healthcare resources (2). Prosthetic tubes made of polyester (Dacron) or polytetrafluoroethylene are often used for the surgical repair of large arteries in aneurysms or acute dissection. Unfortunately, these grafts are so stiff to diameter expansion (3) that they can cause cardiovascular and perfusion problems because they fail to reduce the highly pulsatile nature of the blood flow exiting the heart. This is the reason for an increasing interest in the development of a new generation of grafts (4) in innovative biomaterials or in tissue engineering that mimic the dynamic behavior of the aorta, which is achieved through the correct adjustment of mechanical properties and the introduction of a layered design. Arteries respond to vasoactive chemical stimuli by varying their mechanical properties and diameter because of vascular smooth muscle (VSM) activation; this helps in regulating blood pressure (5). We envision a future generation of aortic grafts based on tissue engineering that mechanically respond to vasoconstrictors to maintain this function. To achieve this result, it is first necessary to investigate the relationship between VSM activation and the mechanical properties of the aorta and to develop a suitable model of the active mechanical response for the graft design. Since the VSM is mainly located in the tunica media (some cells can infiltrate the intima and adventitia with increasing age), the activation strain can be attributed to this aortic layer. Experimental data and a suitable material model for human aortas with smooth muscle activation are not available in the literature despite the need for the development of advanced grafts. This appears to be due to the difficulty of obtaining suitable human samples. In fact, VSM activation is only possible for a small number of hours after the explantation from a heart-beating donor (i.e., donor in intensive care unit with neurological determination of death) and when the tissue is kept refrigerated in organ preservation solution all the time before testing. The present study is important as it provides much-needed experimental data. These data made it possible to create a precise structure-based model of the active aortic tissue and to identify the corresponding material parameters.The passive (i.e., without VSM activation) quasistatic mechanical properties of the intact wall of the human aorta and its three individual layers have been extensively investigated experimentally. In particular, uniaxial extension tests were carried out on strips (cut in the circumferential and longitudinal directions) from the intact wall or separated layers (6–9), and biaxial tests on squares and cruciform samples of aortic tissue (10, 11) were conducted. The microstructure of the collagen and elastin fiber distributions in the three layers was also examined in detail using second-harmonic generation and two-photon excited fluorescence microscopy (9, 10, 12). Along with the progress of experiments, advanced structure-based material models have also been refined. It was assumed that a ground substance/elastin matrix is reinforced by collagen fibers. The orientations and dispersions of the collagen fiber identified from experiments were taken into account in the more advanced models (13–15). The passive dynamic material properties (also referred to as viscoelastic) of the human aortas, on the other hand, are much less studied, even if they are of great importance since the aorta is dynamically loaded by pulsating pressure under physiological conditions. The experiments were performed on a mock circulatory loop under physiological pulsatile pressure and flow (3, 16) and on strips of thoracic descending aortas (8, 17). Viscoelastic models have been developed (18, 19), but they can only partially describe the experimental results. Experimental data show that the aorta stiffens with increasing age (8, 9, 11), which favors hypertension (20).The active (i.e., with VSM activation), quasistatic mechanical characterization of arteries has been less studied than its passive counterpart. The number of studies on human samples is very limited (21, 22), and none have been found on large arteries. Vasoactive agents commonly used to induce VSM contraction are potassium depolarization (KCl) (23), noradrenaline (22), norepinephrine (21), and phenylephrine (24). By using different concentrations of agents, different degrees of activation can be achieved. In previous studies, two methodologies of activation experiments were carried out: 1) pressurization of arterial segments (21, 24–29) and 2) extension tests on arterial strips and rings (5, 22, 30–32). Experiments on strips and rings can be isometric, in which the sample is constantly stretched, and the increase in force from the passive to the active state is measured (5); these are the typical experiments that are carried out on a myograph (22). In isobaric experiments performed on arterial segments, the pressure and axial stretch are fixed; activation of the VSM leads to a reduction in diameter (5). Approximation formulas allow the change in diameter to be linked to the arterial stiffness. Another type of experiment can be performed to measure the force-displacement curve (then converted to stress/strain) in the case of VSM activation by following a similar procedure used for passive mechanical characterization (6–9). A comparison of the active and passive curves gives the mechanical characteristics of the VSM activation. Excluding refs. 5, 28, and 30, a literature review shows that activation was only measured in the circumferential direction. Indeed, the orientation of VSM cells in arteries has usually been believed to be almost circumferential; the present study shows that this is not the case with the descending thoracic aorta in humans. Mechanical models of the mechanical response of active arteries have been developed (5, 14, 33–39) but generally only consider activation in the circumferential direction. There are two exceptions: the model in ref. 5 introduces independent activation stresses in the circumferential and axial directions; another study (38) considers two helically arranged symmetric families of VSM without fiber dispersion.In the present study, the active and passive mechanical characterization of human descending thoracic aortas was performed on specimens from 13 heart-beating donors. The aortic segments were cooled in Belzer UW solution during transport and tested within a few hours after explantation. VSM activation was achieved through the use of KCl and noradrenaline as vasoactive agents. In addition to isometric activation experiments, the quasistatic passive and active stress–strain curves for circumferential and longitudinal strips of the aortic material were obtained. This characterization made it possible to build an original mechanical model of the active aortic material that exactly matched the experimental data. The dynamic mechanical characterization was also performed using cyclic strain at different frequencies of physiological interest. An initial prestretch, which corresponded to the physiological conditions, was applied before the cyclic loading. Dynamic tests allowed to identify the differences in the viscoelastic behavior of the passive and active tissue. The influence of age was also studied. The present study illustrates the importance of VSM activation for the static and dynamic mechanical response of human aortas. Most importantly, it provides material data for the development of a future generation of active aortic grafts that mimic the natural behavior.     

Impairment of left ventricular function in systemic lupus erythematosus evaluated by measuring myocardial performance index with tissue Doppler echocardiography

In 44 patients affected by systemic lupus erythematosus (SLE) without any clinical signs of heart disease (group I) the myocardial performance index (MPI) was calculated to investigate left ventricular function. The index, as the sum of isovolumetric contraction time (ICT) and isovolumetric relaxation time (IRT) divided by ejection time (ET), was measured by tissue Doppler echocardiography (TDE). Results achieved show a prolonged MPI with respect to the values recorded in healthy controls (group II). Its prolongation is due to a significant increase of IRT, whereas ICT and ET were within the normal limits. In patients with SLE without an evident cardiac engagement, this outcome seems to depend on a prevalent diastolic left ventricular dysfunction, perhaps due to a subclinical myocarditis. TDE is more precise than the conventional Doppler method in evaluating MPI and single time intervals, because their measurements are accomplished in concomitance of left ventricular wall motion rather than the flow movement.     

Hemodialysis improves myocardial interstitial edema and left ventricular diastolic function in patients with end-stage renal disease: noninvasive assessment by ultrasonic tissue characterization

Congestive heart failure is the most common cause of mortality in patients with end-stage renal disease (ESRD). Ultrasonic tissue characterization with integrated backscatter offers a promising method for the noninvasive assessment of regional myocardial contractile performance and fibrosis. The aim of this study was to investigate the effect of hemodialysis (HD) on myocardial tissue characterization and left ventricular function in ESRD patients. We examined 26 patients with ESRD undergoing routine HD (age 63 ± 12 years, duration of HD 9.2 ± 3.2 years) and 30 patients with essential hypertension (HT; 60 ± 10 years). Routine echocardiographic parameters and the cyclic variation of ultrasonic integrated backscatter of the ventricular septum (CV-IBS) were measured. Left ventricular mass index was significantly larger in patients with ESRD than in those with HT (217 ± 56 vs 146 ± 45 g/m², P < 0.05). The indices for left ventricular diastolic function (E/A, the ratio of left ventricular peak early to late diastolic filling velocity; DT, the deceleration time of the early diastolic filling) and CV-IBS had deteriorated significantly in patients with ESRD before HD compared with those with HT (E/A, 0.6 ± 0.2 vs 0.9 ± 0.3, P < 0.05; DT, 228 ± 23 vs 184 ± 19 ms, P < 0.05; CV-IBS, 9.0 ± 1.3 vs 12.4 ± 0.9 dB, P < 0.05), possibly reflecting interstitial fibrosis. In patients with ESRD, HD reduced calculated left ventricular mass index by 19% (before HD, 217 ± 56 vs immediately after HD, 176 ± 45 g/m², P < 0.05) and CV-IBS by 19% (9.0 ± 1.3 vs 7.3 ± 1.1 dB, P < 0.05), that possibly reflected improvement of interstitial edema. HD also significantly improved indices for left ventricular diastolic function (E/A, 0.6 ± 0.2 vs 0.9 ± 0.2, P < 0.05; DT, 228 ± 23 vs 188 ± 21 ms, P < 0.05). HD improves myocardial interstitial edema and left ventricular diastolic function in patients with ESRD. Noninvasive assessment of ultrasonic tissue characterization is useful in defining the pathophysiological changes of ventricular myocardium in patients with ESRD. Received: December 17, 2001 / Accepted: April 19, 2002 Correspondence to O. Hirono     

Dynamic assessment of myocardial involvement in patients with end-stage renal disease by ultrasonic tissue characterization and serum markers of collagen metabolism

BACKGROUND: Congestive heart failure is the most common cause of mortality in patients with end-stage renal disease (ESRD). However, noninvasive assessment for cardiac involvement in ESRD has not been established. HYPOTHESIS: Assessment of ultrasonic tissue characterization and serum markers of collagen degradation is useful for defining myocardial involvement in ESRD. METHODS: Cyclic variation of ultrasonic integrated backscatter of the ventricular septum (CV-IBS) and the serum levels of free matrix metalloproteinase-I (MMP-I) and tissue inhibitor of metalloproteinase-I (TIMP-I) were measured in 30 patients with ESRD undergoing routine hemodialysis (HD) and in 40 patients with essential hypertension (HTN). RESULTS: Compared with the group with HTN, ESRD (before HD) showed larger left ventricular (LV) mass index (217 +/- 56 vs. 146 +/- 45 g/m2, p < 0.01), worse LV diastolic function (E/A, 0.6 +/- 0.2 vs. 0.9 +/- 0.3, p < 0.05), smaller CV-IBS (9.0 +/- 1.3 vs. 12.4 +/- 0.9 dB, p < 0.01), and larger TIMP-I/MMP-I (46 +/- 10 vs. 34 +/- 10, p < 0.05), in spite of the comparable ventricular wall thickness. Thus, these indices may possibly reflect myocardial interstitial fibrosis. After HD (after the improvement of myocardial interstitial edema), a negative linear relationship between CV-IBS and TIMP-I/MMP-I was observed (r= -0.52, p < 0.05). CONCLUSIONS: Noninvasive assessment of ultrasonic tissue characterization and serum markers of collagen type I degradation may be a new diagnostic tool for defining myocardial interstitial fibrosis in patients with ESRD and LV hypertrophy.     

肥厚性心肌病心肌超声背向散射积分心动周期变动量与左室舒张功能的关系初探

目的 :研究心肌超声组织背向散射积分 （integrated backscatter,IB）心动周期平均变动量 （average cardiaccyclic variation of IB,ACVIB）与心脏舒张功能的关系 ,探讨应用 ACVIB评估心脏舒张功能的可行性。方法 :按WHO/ISFC-1995制定的标准诊断为肥厚性心肌病 （HCM）的患者 18例定为 HCM组 ,健康人 2 2例定为对照组。应用 Agilent-5 5 0 0型超声诊断仪 ,1检测 2组研究对象的左心室 （LV） IB曲线 ,记录 L V乳头肌水平和腱索水平 2个短轴切面的左室前间隔、后壁心肌组织的 IB心动周期变动量 （cyclic variation of IB,CVIB） ,计算出 ACVIB;2检测2组研究对象的 LV舒张功能。 3对 40例研究对象的 ACVIB与 LV舒张功能各指标的关系进行直线相关回归分析。结果 :HCM组与对照组比较 :ACVIB显著减低 ,同时心脏舒张功能显著减退。相关回归分析结果表明 ,40例研究对象 LV心肌 ACVIB的减小与大部分心脏舒张功能指标变化密切相关 ,包括 :1与 Ve和 Ve/Va相关 (r=0 .5 8和 0 .65 ,均 P<0 .0 1;2与 DT相关 （r=-0 .83 ,P<0 .0 1） ;3与 Vd以及 Vs/Vd密切相关 （r=-0 .5 7及 -0 .68,均P<0 .0 1）。结论 :HCM患者的 LV心肌 ACVIB的改变与 L V舒张功能减退之间存在变化规律 ,ACVIB的减小与舒张功能减退密切相关。通过观察心肌 ACVIB     

The effect of isolated left bundle branch block on the myocardial velocities and myocardial performance index

OBJECTIVES: This study was planned in order to investigate the effect of left bundle branch block (LBBB) on myocardial velocities obtained by tissue Doppler echocardiography (TDE) and myocardial performance index (MPI). METHODS: Subjects with LBBB (n = 61) and age-matched healthy subjects (n = 60) were enrolled in the study. Left ventricular (LV) ejection fraction (EF), mitral inflow velocities (E-wave and A-wave), isovolumetric contraction and relaxation time (ICT and IRT), ejection time (ET), and flow propagation velocity (Vp) were measured by conventional echocardiography. Systolic velocity (Sm), early and late diastolic velocities (Em and Am) and time intervals were measured by TDE. MPI was calculated by the formula (ICT + IRT)/ET. RESULTS: LVEF and mitral E/A ratio were similar in both groups. Vp was lower in the LBBB group than in the control group, whereas the E/Em and the E/Vp ratio was higher. LV Sm and Em/Am ratio were lower in LBBB group. Right ventricular Sm and Em/Am ratio were similar in both groups. LV mean and RV MPI were significantly increased in LBBB group. CONCLUSION: These findings obtained by TDE show that isolated LBBB impairs the ventricular functions. Both of the LV and RV dysfunctions shown by the new parameters may contribute to increased morbidity and mortality in cases with isolated LBBB.     

Right ventricular thickness as predictor of global myocardial performance in systemic sclerosis: A Doppler tissue imaging study

Background

Cardiopulmonary involvement in systemic sclerosis (SSc) is a poor prognostic factor, due to pulmonary hypertension and right ventricular dysfunction. We assessed the echocardiographic parameters of right ventricular (RV) function in SSc and correlated echocardiographic findings to clinical features of the disease.

Methods

Thirty patients with SSc (cases) and 30 healthy, age-matched subjects (controls) were studied. Echocardiography, including tissue Doppler imaging, was used to evaluate cardiac function.

Results

Pulmonary hypertension could be documented in only 5 cases by Doppler echo, using Bernoulli principle. RV diastolic function was significantly deranged in cases. RV systolic function and left ventricle (LV) diastolic function were also significantly deranged in the cases. RV thickness was increased in patients with SSc. There were no significant differences in the echocardiographic variables between diffuse and limited subtypes of SSc. Myocardial performance index (MPI) of both ventricles were increased in cases. We could demonstrate RV thickness as the single most important predictor of MPI of both ventricles with sensitivity of 82% and specificity of 72% for RV-MPI and 63% for LV-MPI. Diastolic function was not found to be affected by disease duration or Rodnan skin score.

Conclusion

Patients with SSc exhibit abnormal RV and LV diastolic functions as well as abnormal RV systolic function. RV wall thickness was found to be simple and the single best predictor of global myocardial performance. RV dysfunction may be a response to intermittent pulmonary arterial hypertension, lung parenchymal involvement, or secondary to LV diastolic dysfunction in SSc.Abbreviations: ACE-I, angiotensin converting enzyme inhibitor; DT, deceleration time; DTI, Doppler tissue imaging; E/A ratio, early diastolic/atrial component velocity ratio; ET, ejection time; FVC, forced vital capacity; Hct, hematocrit; HRCT, high-resolution computed tomography; IVCT/ICT, isovolumic contraction time; ILD, interstitial lung disease; IVRT/IRT, isovolumic relaxation time; LV, left ventricle/ventricular; LVEDD, left ventricular end diastolic dimension; LVEDV, left ventricular end diastolic volume; LVEF, left ventricular ejection fraction; LVESD, left ventricular end systolic dimension; LVESV, left ventricular end systolic volume; MPI, myocardial performance index; PAH, pulmonary arterial hypertension; PAP, pulmonary artery pressure; PASP, pulmonary artery systolic pressure; PAT, pulmonary acceleration time; RR, electrocardiographic R–R interval; RVEF, right ventricular ejection fraction; RV, right ventricle/ventricular; SSc, systemic sclerosis