Quantitative dobutamine stress echocardiography for the early detection of cardiac allograft vasculopathy in heart transplant recipients

BACKGROUND

A non-invasive method to detect the presence of cardiac allograft vasculopathy (CAV) remains an important goal in clinical cardiology.

OBJECTIVE

To assess the value of quantitative dobutamine stress echocardiography (DSE) for the early detection of CAV.

METHODS

42 heart transplant recipients underwent DSE with acquisition of both conventional two-dimensional and colour tissue Doppler data. All studies were analysed conventionally and quantitatively using regional deformation parameters-that is, peak systolic longitudinal strain (in(peak sys)), strain rate (SR(peak sys)) and post-systolic strain index. Myocardial segments were classified as normal, mildly abnormal or severely abnormal based on correlative angiographic findings.

RESULTS

At baseline, in(peak sys) was significantly lower in severely abnormal segments than in normal ones. However, at peak stress, in(peak sys) was able to separate three groups of segments. Receiver operating characteristic analysis showed an SR(peak sys) response of <0.5/s to identify patients with CAV with a sensitivity of 88%, specificity of 85% and a negative predictive value of 92%.

CONCLUSION

Regional myocardial function is impaired in heart transplant recipients with CAV even when the disease is considered to be non-significant on conventional angiography. Systolic deformation parameters tended to detect the existence of CAV more accurately than conventional visual DSE assessment. Strain rate imaging during stress can therefore safely be used as a non-invasive screening test for detecting CAV in heart transplant recipients.

A 3-D CT image of a left atrial thrombus sparing only the ostia of the pulmonary veins

A 58-year old woman was referred because of progressive heart failure since three weeks. Because of peripheral oedema and the presence of a diastolic murmur an echocardiography is performed showing a mitral stenosis and the presence of a thrombus in the left atrium. We present 3-D Computed Tomography (CT) images that show the massive extent of the left atrial thrombus only sparing the ostia of the pulmonary veins. A clue for diagnosis for mitral stenosis is the presence of an rumbling mid-diastolic murmur.

Regional right ventricular dysfunction in chronic pulmonary hypertension

OBJECTIVE

Right ventricular (RV) failure is the main cause of mortality in patients with pulmonary hypertension (PH). Therefore, there is an increasing interest for the assessment of RV function. This study aimed to evaluate the regional RV function in patients with PH by using ultrasonic strain rate imaging.

METHODS

In all, 27 patients with PH and 27 control subjects were studied by ultrasonic strain rate imaging. The regional longitudinal deformation was measured in the RV free wall divided into two segments. A subgroup of 16 patients had concomitant invasive hemodynamic measurements.

RESULTS

In patients with PH, deformation parameters were significantly lower compared with that of control subjects (basal strain rate -2.28 +/- 0.9 vs -2.94 +/- 0.9 s(-1); strain -28 +/- 13% vs -42 +/- 11%; apical strain rate -1.05 +/- 1.38 vs -2.60 +/- 0.9 s(-1); strain -13 +/- 16% vs -41 +/- 11%, respectively). The deformation parameters in the apical segment were reduced more than in the basal segment (the segment-wise comparison with P < .002 for strain rate and P < .0001 for strain) in the patient group. The reduction of the apical deformation was related to the severity of RV afterload. Strong correlations were found between the apical strain and invasively measured mean pulmonary arterial pressure (R = 0.82, P < .0001) and pulmonary vascular resistance (R = 0.73, P < .001) and echocardiographically estimated hemodynamic parameters, RV size and global function, and exercise capacity (evaluated by a 6-minute walk test expressed as a percentage of the expected value).

CONCLUSION

Strain rate imaging provides a new tool to quantify regional RV dysfunction in patients with PH and reveals a characteristic regional pattern of abnormal RV free wall function.

The potential clinical role of ultrasonic strain and strain rate imaging in diagnosing acute rejection after heart transplantation

BACKGROUND

There has been a continued search for a more sensitive noninvasive technique for detecting sub-clinical acute rejection in heart transplant recipients. Ultrasonic deformation imaging (strain/strain rate) is sensitive in detecting sub-clinical abnormalities in regional systolic function and could potentially be sufficiently sensitive to detect changes in deformation induced by graft rejection.

AIM

To assess the use of strain (S) and strain rate (SR) imaging as a noninvasive method for monitoring and diagnosing acute rejection in heart transplant recipients.

METHODS AND RESULTS

A prospective preliminary study was carried out involving 31 consecutive heart transplant patients who underwent a total of 106 routine follow up endomyocardial biopsy with correlative cardiac ultrasound data. To assess regional longitudinal deformation, ultrasonic S and SR data were acquired from the intraventricular septum, left ventricular (LV) lateral and right ventricular free walls (RVFW). For radial deformation, data were obtained from the LV posterior wall (LVPW). According to the International Society of Heart and Lung Transplantation criteria, 88 biopsies (Group 1) had grade 0 or IA rejection, and 18 biopsies (Group 2) had > or =grade IB rejection. Longitudinal peak systolic S and SR were decreased (p<0.05) in Group 2, compared to Group 1 in the RVFW basal and apical segments and the basal and mid segments of the LV lateral wall. Radial peak systolic S and SR were significantly lower (p<0.001) in Group 2, compared to Group 1.

CONCLUSIONS

S/SR imaging might be a good technique and an additional tool for detecting > or =IB grade of acute rejection. The myocardial deformation, as assessed by S/SR imaging could be of clinical value in monitoring and diagnosing acute rejection in heart transplant recipients and could improve patients' management by reducing the number of biopsies performed.

Comparison of real-time tri-plane and conventional 2D dobutamine stress echocardiography for the assessment of coronary artery disease

AIMS

Although dobutamine stress echocardiography (DSE) is an accepted tool for the diagnosis of coronary artery disease (CAD), it requires subsequent image acquisitions of the left ventricle (LV) in order to visualize all segments. This makes the procedure relatively time-consuming and might limit its accuracy. With the introduction of matrix array transducers, the real-time simultaneous acquisition of all LV segments has become possible using multi-plane imaging. The purpose of this study was: (i) to test the feasibility and efficiency of real-time tri-plane (RT3P) imaging during DSE, (ii) to compare the accuracy of RT3P DSE in detecting CAD using coronary angiography as the reference method.

METHODS AND RESULTS

Thirty-six patients suspected of CAD were prospectively enrolled. Both conventional two-dimensional (2D) and RT3P imaging were performed during a DSE protocol. Coronary angiography was performed within 24 h. Ultrasound data were acquired at each stage of the DSE. The total effective acquisition time for RT3P imaging was significantly shorter (55+/-29 vs. 137+/-63 s, P<0.001). Data yield was similar for both methods (2D: 98% vs. 3D: 97%). Overall sensitivity (93%), specificity (75%), and accuracy (89%) were identical between both methods. On a segmental level, the sensitivity, specificity, and accuracy of the RT3P and the 2D DSE were similar.

CONCLUSION

RT3P imaging fastens the DSE protocol without compromising the accuracy for the diagnosis of CAD. This could facilitate a more wide-spread use of DSE and therefore contributes positively to its routine clinical acceptance.

Autologous bone marrow-derived stem-cell transfer in patients with ST-segment elevation myocardial infarction: double-blind, randomised controlled trial

BACKGROUND

The benefit of reperfusion therapies for ST-elevation acute myocardial infarction (STEMI) is limited by post-infarction left-ventricular (LV) dysfunction. Our aim was to investigate the effect of autologous bone marrow-derived stem cell (BMSC) transfer in the infarct-related artery on LV function and structure.

METHODS

We did a randomised, double-blind, placebo-controlled study in 67 patients from whom we harvested bone marrow 1 day after successful percutaneous coronary intervention for STEMI. We assigned patients optimum medical treatment and infusion of placebo (n=34) or BMSC (n=33). Our primary endpoint was the increase in LV ejection fraction and our secondary endpoints were change in infarct size and regional LV function at 4 months' follow-up, all assessed by MRI. We assessed changes in myocardial perfusion and oxidative metabolism with serial 1-[11C]acetate PET. Analyses were per protocol. This study is registered with , number NCT00264316.

FINDINGS

Mean global LV ejection fraction 4 days after percutaneous coronary intervention was 46.9% (SD 8.2) in controls and 48.5% (7.2) in BMSC patients, and increased after 4 months to 49.1% (10.7) and 51.8% (8.8; OR for treatment effect 1.036, 95% CI 0.961-1.118, p=0.36). Compared with placebo infusion, BMSC transfer was associated with a significant reduction in myocardial infarct size (BMSC treatment effect 28%, p=0.036) and a better recovery of regional systolic function. Myocardial perfusion and metabolism increased similarly in both groups. We noted no complications associated with BMSC transfer and all but one patient in the BMSC group completed the 4 months' follow-up.

INTERPRETATION

Intracoronary transfer of autologous bone marrow cells within 24 h of optimum reperfusion therapy does not augment recovery of global LV function after myocardial infarction, but could favourably affect infarct remodelling.

The Evaluation of Pulmonary Hypertension Using Right Ventricular Myocardial Isovolumic Relaxation Time

Right ventricular (RV) blood pool-derived isovolumic relaxation time (IVRT) correlates well with systolic pulmonary arterial pressure (PAP). However, because of complex parameter derivation, the method is rarely used. The aim of this study was to validate the measurement of myocardial velocity imaging-derived RV IVRT (IVRT') against invasively measured PAP. Transthoracic echocardiography with myocardial velocity imaging and right heart catheterization were performed in 33 patients with pulmonary hypertension. Blood pool IVRT and myocardial IVRTs for the tricuspid valve annulus ring, basal and apical RV free wall segments were measured and compared with data from 33 age- and sex-matched control subjects. Measured IVRTs were significantly longer in patients with pulmonary hypertension than in control subjects. The strongest correlation (R = 0.74, P < .0001) was found between systolic PAP and the heart rate-corrected IVRT' derived from the basal RV free wall segment. The basal segment IVRT' corrected for heart rate correlates well with the invasive PAP measurement and, therefore, can be used to predict systolic PAP. It can even be considered as an alternative to tricuspid regurgitation-derived PAP systolic when tricuspid regurgitation is nonrecordable. A proposed method to derive systolic PAP should be used while screening the patients at risk for pulmonary hypertension, monitoring the disease progression and the effect of treatment.

Feasibility of strain and strain rate imaging for the assessment of regional left atrial deformation: a study in normal subjects

AIMS

There are no data on the use of Myocardial Velocity Imaging (MVI) to study the left atrium (LA) wall deformation. The aims of this study were to assess the feasibility of measuring regional longitudinal strain/strain rate (epsilon/SR) profiles in the LA wall, to define the normal values and to validate these measurements.

METHODS AND RESULTS

MVI data were recorded in 40 healthy young individuals using a GE Vivid7 for the lateral, anterior and inferior LA walls. The peak epsilon/SR values and total epsilon values during the contractile, reservoir and conduit LA phases were measured. For the LA lateral wall, the total epsilon values were correlated with the LA volumetric indicators (LA active emptying fraction: LA AEF; LA expansion index: LA EI; and LA passive emptying fraction: LA PEF). The correlations were significant for all three periods: contractile (total epsilon vs. LA AEF, r=-0.78, P<0.001), reservoir (total epsilon vs. LA EI, r=0.43, P<0.01) and conduit (total epsilon vs. LA PEF, r=-0.46, P<0.005).

CONCLUSION

SR/epsilon imaging for the quantification of longitudinal myocardial LA deformation was shown to be feasible and the normal values were reported and validated. These data may improve the understanding of the LA pathophysiology.

Ultrasonic strain/strain rate imaging—a new clinical tool to evaluate the transplanted heart

OBJECTIVE

The aim of this study was to investigate the clinical applicability of strain and strain rate imaging (epsilon/SRI) in heart transplantation (Htx) patients and to establish "normal" post-Htx regional systolic deformation values.

BACKGROUND

Epsilon/SR indices have been shown to be a more sensitive measure of regional systolic function than standard echo measurements. Thus, they might provide a new tool to better define both normal cardiac graft function and detect changes due to post-Htx complications. However, prior to investigating the role of epsilon/SRI in detecting abnormalities, "normal" post-Htx regional deformation values must be established as graft regional function can be altered by a number of factors such as ischemic time, surgical technique or accelerated graft ageing.

METHODS

A total of 57 Htx patients (age 36+/-12 years; post-Htx 5.5+/-3 years) without any documented complication were studied. Epsilon/SRI data were acquired from the septum, left ventricular (LV) free walls and right ventricular free wall (RVFW). A total of 29 age-matched healthy subjects served as controls.

RESULTS

Htx longitudinal peak systolic velocities (Vsys) were lower in inferior, septal and RVFW segments compared to controls. Peak systolic epsilon/SR (epsilonsys/SRsys)) did not differ from controls except in septum and RVFW in which the values were significantly reduced. Radial Vsys) in the Htx group were higher than controls while epsilonsys/SRsys were reduced. There was a significant decrease in SR(sys) in apical LV segments with increasing time post-Htx, whereas those measured in RVFW showed an increase by that time.

CONCLUSION

Epsilon/SRI demonstrated that "healthy" Htx hearts have normal global systolic function but altered regional systolic deformation indices compared to normal hearts. Post-Htx time has a diminishing effect on the regional systolic deformation indices in LV segments but an improving effect in RVFW. These "normal" Htx values should provide the basis for subsequent studies into the role of epsilon/SRI in the non-invasive detection of post-Htx complications.

New aspects of the ventricular septum and its function: an echocardiographic study

OBJECTIVES

To examine whether the line dividing the septum into two layers is found consistently by conventional echocardiography and to evaluate functional differences in the right and left side of the septum in terms of wall thickening, strain rate, and strain imaging.

DESIGN

In a systematic study in 30 normal subjects, M mode and Doppler myocardial imaging data from the interventricular septum (IVS) were recorded. Velocity curves, regional strain rate, and strain profiles were obtained. Systolic deformation (wall thickening, radial and longitudinal strain rate, and strain) of both sides were assessed. Furthermore, three patients with one sided abnormalities were studied.

RESULTS

A bright echo consistently segmented the IVS into a left and right part. In this normal population radial deformation was different for the left and right side of the septum (mean (SD) wall thickening on the left, 49 (46)%, and on the right, 17 (38)%; strain rate on the left, 3.8 (0.6) 1/s, and on the right, 2.1 (1.9) 1/s; strain on the left, 41 (17)%, and on the right, 22 (14)%), whereas longitudinal deformation was found to be similar (strain rate on the left, -2.2 (0.7) 1/s, and on the right, -2.0 (0.6) 1/s; strain on the left, -28 (12)%, and on the right, -25 (12)%). The presented clinical examples show that abnormalities can be strictly limited to one layer.

CONCLUSIONS

Differential radial deformation and knowledge of fibre architecture showing an abrupt change in the middle of the septum, together with the clinical cases, suggest the septum to be a morphologically and functionally bilayered structure potentially supplied by different coronary arteries.

Quantifying myocardial deformation throughout the cardiac cycle: a comparison of ultrasound strain rate, grey-scale M-mode and magnetic resonance imaging

Strain rate imaging (SRI) is a new ultrasound (US) approach to the quantification of regional myocardial deformation. It previously has been validated in vitro and in vivo against other imaging techniques. However, in all such studies, only peak strain values were compared, and the temporal evolution of the strain curve was not studied. Yet, it is the temporal evolution of the strain curves that contains the more important clinical information (e.g., asynchrony, viability, etc). Thus, the aim of this study was to compare the evolution of strain during the complete cardiac cycle as measured by US SRI, US grey-scale M-mode and magnetic resonance imaging (MRI). In 10 healthy volunteers and 20 patients with chronic ischaemic heart disease, radial deformation of the inferolateral segment of the left ventricle was measured by US SRI, US M-mode and MRI. The correspondence of the temporal characteristics of these strain curves were compared by defining an intraclass correlation coefficient (ICC). In healthy volunteers, an overall good agreement (mean ICC: 0.75 and 0.63 for systole and diastole) was found between the different methods. However, in patients with abnormal segmental deformation and low peak strain values, the agreement was less (mean ICC: 0.42 and 0.32), but remained within acceptable limits for clinical decision making. Myocardial deformation measurements using SRI correlated well with MRI and US M-mode measurements throughout the complete cardiac cycle.

Restrictive left ventricular filling in hypereosinophilic syndrome as a result of partial cavity obliteration by an apical mass: a strain/strain rate study

We present a case of hypereosinophilic syndrome with a large apical mass, which markedly reduced end-systolic left ventricular cavity volume. Standard blood pool Doppler findings showed a restrictive filling pattern. However, ultrasound-derived regional strain rate and strain parameters suggested that wall deformation was not compromised, inferring that the restrictive filling pattern in this case was solely as a result of the reduction in end-systolic cavity size.

Cardiac resynchronization therapy can reverse abnormal myocardial strain distribution in patients with heart failure and left bundle branch block

OBJECTIVES

We studied the effects of cardiac resynchronization therapy (CRT) on regional myocardial strain distribution, as determined by echocardiographic strain rate (SR) imaging.

BACKGROUND

Dilated hearts with left bundle branch block (LBBB) have an abnormal redistribution of myocardial fiber strain. The effects of CRT on such abnormal strain patterns are unknown.

METHODS

We studied 18 patients (12 males and 6 females; mean age 65 +/- 11 years [range 33 to 76 years]) with symptomatic systolic heart failure and LBBB. Doppler myocardial imaging studies were performed to acquire regional longitudinal systolic velocity (cm/s), systolic SR (s(-1)), and systolic strain (%) data from the basal and mid-segments of the septum and lateral wall before and after CRT. By convention, negative SR and strain values indicate longitudinal shortening.

RESULTS

Before CRT, mid-septal peak SR and peak strain were lower than in the mid-lateral wall (peak SR: -0.79 +/- 0.5 [septum] vs. -1.35 +/- 0.8 [lateral wall], p < 0.05; peak strain: -7 +/- 5 [septum] vs. -11 +/- 5 [lateral wall], p < 0.05). This relationship was reversed during CRT (peak SR: -1.35 +/- 0.8 [septum] vs. -0.93 +/- 0.6 [lateral wall], p < 0.05; peak strain: -11 +/- 6 [septum] vs. -7 +/- 6 [lateral wall], p < 0.05). Cardiac resynchronization therapy reversed the septal-lateral difference in mid-segmental peak strain from -46 +/- 94 ms (LBBB) to 17 +/- 92 ms (CRT; p < 0.05).

CONCLUSIONS

Left bundle branch block can lead to a significant redistribution of abnormal myocardial fiber strains. These abnormal changes in the extent and timing of septal-lateral strain relationships can be reversed by CRT. The noninvasive identification of specific abnormal but reversible strain patterns should help to improve patient selection for CRT.

One-dimensional ultrasonic strain and strain rate imaging: a new approach to the quantitation of regional myocardial function in patients with aortic stenosis

Abnormalities in regional left ventricular (LV) function in aortic stenosis (AS) have yet to be appropriately characterized. One-dimensional strain (epsilon) and strain rate imaging (SRI), new ultrasound (US) indices for quantifying regional wall deformation, might allow this. The aims of this study were 1. to define regional radial and longitudinal epsilon /SR in AS; 2. to establish if they are related to the severity of the disease; and 3. to determine if regional deformation is further altered by coexistent coronary artery disease (CAD). A total of 40 patients were studied: Group I with isolated AS (10 women, 10 men; mean age 66 years) and group II with AS and concomitant CAD (CAD/AS) (13 women, 7 men, mean age 68 years). Data were compared to 20 age-matched healthy people (N). Regional systolic maximal velocity/SR and end-systolic and maximal epsilon were measured. The maximal systolic velocity/SR in AS and CAD/AS patients were significantly reduced compared to N. The two patient groups could be further differentiated by end-systolic and maximal epsilon, which demonstrated a further reduction in both epsilon indices in CAD/AS (i.e., maximal radial epsilon 29.3%, AS; 23.7%, CAD/AS; 40.4%, N; AS and CAD/AS vs. N, AS vs. CAD/AS, p < 0.05). Indices of radial and longitudinal deformation correlated both with aortic valve area (AVA) and stroke volume (SV) (i.e., radial maximal epsilon and AVA, r = 0.77, p < 0.05). A significant correlation was also found between epsilon indices and the severity of left anterior descending (LAD) or circumflex artery (CX) coronary artery. Regional myocardial deformation in AS is abnormal. In the absence of CAD, the degree of abnormality correlates with aortic valve area (AVA). The severity of the disease was best expressed by changes in regional epsilon. In CAD/AS patients, there was a significant further reduction in end-systolic and maximal epsilon. These changes correlated with the severity of coronary narrowing in the subtending vessel.

ST-deviation reconstruction in missing leads on the 12-lead ECG: applicability in studies on ST-segment resolution during thrombolysis

Quantitative analysis of ST-segment deviations (STdev) and their resolution by treatment (STR; calculated from a combined sum of STdev in multiple leads) are used in trials on reperfusion for myocardial infarction (MI). Unreadable or unavailable electrocardiogram (ECG) leads are a common reason for exclusion, decreasing the statistical power of the trials. We developed mathematical formulas for reconstruction of immeasurable STdev based on STdev from other available leads on the 12-lead ECG. Formulas were deducted from a database of computer-assisted STdev measurements in 2 ECGs (baseline and 180 min after thrombolysis) of 1121 pts. Their accuracy was later evaluated on a second dataset of 377 pts. Acceptable fits could be derived for absent single leads, or for groups of absent limb leads (I-II-III or aVL-aVF). The intraclass correlation coefficient between real and calculated STdev was >or= 0.80 for each (0.77 for V1 in inferior MI). The correlations between STR calculated from original data and from reconstructed STdev were very strong (all intraclass correlation >or=0.97), and discordance in STR subgroup categorization occurred in <or=10% of pts in all but one of the scenarios (I-II-III substituted in 180 min ECG in inferior MI). Scenarios with multiple missing precordial leads however are not substitutable, nor are calculated STdev reliable for STR evaluation in only the lead with highest elevation in baseline. STdev reconstruction formulas can reliably be used in trials where analysis of aggregate STR is an endpoint. Reliable substitution can significantly increase the number of evaluable patients and therefore strengthen the statistical power of these trials.

The feasibility of ultrasonic regional strain and strain rate imaging in quantifying dobutamine stress echocardiography

BACKGROUND

Ultrasonic strain rate and strain can characterize regional one-dimensional myocardial deformation at rest. In theory, these deformation indices could be used to quantify normal or abnormal regional function during a dobutamine stress echo test.

AIMS

The aims of our pilot study were threefold: (1) to determine the percentage of segments in which interpretable strain rate/strain data could be obtained during routine dobutamine stress echo, (2) to establish whether either the increase in heart rate or artefacts induced by respiration during dobutamine stress echo would influence analysis by degrading the data and (3) to determine the optimal frame rate vs image sector angle settings for data acquisition. Furthermore, although the detection of ischaemia was not to be addressed specifically in this study, we would describe the findings on the potential clinical role of regional deformation vs velocity imaging in detecting ischaemia-induced changes.

METHODS

A standard dobutamine stress echo protocol was performed in 20 consecutive patients with a history of chest pain (16 with angiographic coronary artery disease and four with normal coronary angiograms). DMI velocities were acquired at baseline, low dose, peak dose, and recovery. To evaluate radial function (basal segment of the left ventricle posterior wall segment), parasternal LAX, SAX views were used. For long axis function data were acquired (4-CH, 2-CH views) from the septum; lateral, inferior and anterior left ventricle walls. Data was acquired using both 15 degrees (>150 frames per second (fps) and 45 degrees (115fps) sector angles. During post-processing each wall was divided into three segments: basal, mid and apical. Strain rate/strain values were averaged over three consecutive heart cycles.

RESULTS

Data was obtained from 1936 segments, of which only 54 had to be excluded from subsequent analysis (2.8%) because of suboptimal quality. An increase in heart rates (up to 150/min) was not associated with a significant reduction in the number of interpretable segments. There was a significant correlation between maximal systolic strain rate/strain values obtained at narrow and at wide sector angles (e.g. a correlation for the septal segments: r=0.73,P <0.001 for strain rate, and r=0.71; P<0.001 for strain). The correlation for the timing of events obtained from narrow and wide sector angles was weaker. This would indicate that there was the insufficient temporal resolution for the latter acquisition method. Normal and abnormal regional strain rate/strain responses to an incremental dobutamine infusion were defined. In normal segments, maximal systolic strain rate values increased continuously from baseline, reaching the highest values at the peak dose of dobutamine. The segmental strain response was different. For strain, there was an initial slight increase at low dose of dobutamine (5, 10 microg/kg/min), but no further increase with increasing dose. A pattern representing an ischaemic response was identified and described.

CONCLUSIONS

The feasibility study would suggest that with appropriate data collection and post-processing methodologies, strain rate/strain imaging can be applied to the quantification of dobutamine stress echo. However, appropriate post-processing algorithms must be introduced to reduce data analysis time in order to make this a practical clinical technique.

Differential changes in regional right ventricular function before and after a bilateral lung transplantation: an ultrasonic strain and strain rate study

The evaluation of regional right ventricular function by ultrasound remains a challenge. This case report demonstrates the potential value of the new cardiac deformation indices, strain and strain rate imaging, in determining the differing regional abnormalities in longitudinal right ventricular function before and after bilateral lung transplantation. These indices were measured in a patient with severe right ventricular dysfunction as a result of primary pulmonary hypertension.

Identification of acutely ischemic myocardium using ultrasonic strain measurements. A clinical study in patients undergoing coronary angioplasty

OBJECTIVES

The goal of this study was to investigate whether the changes in myocardial deformation measured with ultrasonic strain could accurately identify acutely ischemic myocardium during coronary angioplasty.

BACKGROUND

Early identification of acute myocardial ischemia has important clinical implications. The accuracy of ultrasonic strain for the detection of acute myocardial ischemia has been validated in animal experiments but has not been investigated in the clinical setting.

METHODS

In 73 patients (64 +/- 12 years), either radial or longitudinal strain values were monitored in the "at-risk" segments before, during, and early after right, circumflex, and left anterior descending coronary angioplasty. Based on the visual wall motion assessed before the angioplasty, segments were divided into normokinetic (group I) and hypo/akinetic (group II). Strain data in the "at-risk " segments were compared with values derived from the adjacent nonischemic segments and normal values in 20 controls.

RESULTS

Coronary occlusion induced a marked reduction in the systolic strain both in the radial (from 49 +/- 6.9% to 23 +/- 4.6% in group I and from 21.9 +/- 11% to 11.3 +/- 8.4% in group II, p < 0.001) and longitudinal directions. Concomitantly, postsystolic strain increased (from 3.8 +/- 3.1% to 14.6 +/- 9.5% in group I, and from 4.4 +/- 3.7% to 11.3 +/- 7.8% in group II in radial direction, p < 0.001). Upon reperfusion, all deformation parameters returned to near preocclusion values. In comparison with control, baseline, and reperfusion data, the systolic and postsystolic strain parameters measured during total coronary occlusion identified acutely ischemic myocardium with a sensitivity of 86% to 95% and a specificity of 83% to 89%.

CONCLUSIONS

In this model of acute ischemia, ultrasonic strain indexes differentiate acutely ischemic segments from both normal and dysfunctional myocardium. This should be a promising new approach to the bedside monitoring of acute ischemic changes in regional myocardial function.

The potential value of ultrasonic deformation measurement in differentiating regional ischaemic substrates during dobutamine stress echocardiography

The differentiation between differing regional ischaemic substrates is crucial for decision-making in patients with coronary artery disease. This study demonstrates that quantification of dobutamine stress echocardiography using ultrasonic strain measurement has the potential to identify three differing regional ischaemic substrates (ischaemic, stunned and scarred) in the same patient. The data were validated by traditional analysis of dobutamine stress echo, coronary angiography and correlative quantitative positron emission tomography information.

Visualization of ventricular thrombi with contrast-enhanced magnetic resonance imaging in patients with ischemic heart disease

BACKGROUND

Ventricular thrombus formation is a frequent and potentially dangerous complication in patients with ischemic heart disease. Although transthoracic echocardiography (TTE) is generally used as diagnostic technique, we explored the role of contrast-enhanced (CE)-MRI to detect ventricular thrombi.

METHODS AND RESULTS

In 57 patients with acute myocardial infarction, chronic myocardial infarction, or ischemic cardiomyopathy, MRI was performed to evaluate ventricular function (CINE-MRI) and to depict presence of myocardial necrosis and/or scarring and no-reflow areas (CE-MRI). All studies were analyzed for concomitant ventricular thrombi. CE-MRI depicted 12 mural thrombi (3.1+/-2.9 cm3), located in left ventricular (LV) apex or adherent to anteroseptum, presenting as black, well-defined structures surrounded by bright contrast-enhanced blood. Thrombus formation on CE-MRI was related to larger end-diastolic volumes; lower ejection fractions; the region of delayed enhancement and lowest wall motion score, especially in left anterior descending coronary artery territory; and LV aneurysm formation. On CINE-MRI, thrombi were found in 6 patients. Nonvisualized thrombi were usually small (mean size 1.2+/-0.7 cm3). TTE depicted thrombi in 5. Nonvisualized lesions were most frequently located in LV apex and had a larger size than nonvisualized lesions on CINE-MRI (3.0+/-3.2 cm3). In 3 patients with suspected apical thrombus on TTE, MRI was normal.

CONCLUSIONS

CE-MRI is not only an excellent technique to depict myocardial necrosis and scar tissue in patients with ischemic heart disease, but this study also suggests a better identification of LV thrombi than with presently used clinical imaging modalities, such as TTE.