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Biomedical subjects

C E Angermann

Publications and source records attributed to C E Angermann.

At least 37 records · Page 2Linked to original sources
PubMed1998

Adult human cardiomyocytes coexpress vimentin and Ki67 in heart transplant rejection and in dilated cardiomyopathy.

BACKGROUND: The aim of this study was to investigate whether adult human cardiomyocytes may reexpress vimentin and whether this is linked to cellular activation. METHODS: Myocardial samples of 81 heart transplant recipients (n=183) and patients with dilated cardiomyopathy (n=10) were investigated by immunohistochemistry with the use of the marker molecule vimentin, the muscle-specific protein desmin, and Ki67, a marker for cell activation. RESULTS: Vimentin protein expression in cardiomyocytes was found in 28 samples of transplant recipients and 5 myocardial samples of patients with dilated cardiomyopathy. Coexpression of vimentin and Ki67 was found in 52 of 340 vimentin-positive cardiomyocytes. CONCLUSIONS: We suggest that the vimentin/Ki67 coexpression indicates cell activation processes as the result of different growth stimuli.

Adult↗
PubMed1997

[Prospective study of the frequency and extent of donor-transmitted coronary disease after heart transplantation by intravascular ultrasound].

PROBLEM AND OBJECTIVE: Cardiac allograft vasculopathy influences long-term survival of patients after heart transplantation. Donor-transmitted coronary artery disease may contribute to the further development of cardiac allograft vasculopathy. The aim of this study was to characterize by intracoronary ultrasound the extent and frequency of transmitted coronary artery disease. PATIENTS AND METHODS: Intravascular ultrasound studies were performed at routine angiography in 33 patients (26 men, 7 women, mean age 51 [23-69] years) early after heart transplantation. Plaque morphology was analysed in 153 coronary segments of 52 epicardial coronary arteries. RESULTS: Relevant atherosclerosis (defined as maximal plaque thickness > or = 0.5 mm in at least one coronary segment) was found in 17 patients (52%), while angiography showed irregularities in only 7 patients (21%). Maximal plaque thickness in patients with relevant atherosclerosis was 1.13 +/- 0.32 mm, mean plaque index was 19.2 +/- 10.2%. Plaque formation was eccentric, and plaques were predominantly located in proximal segments. Morphologic changes affecting more than one segment were found in 52% of the patients. Comparing clinical factors, only donor age predicted the degree of atherosclerosis. CONCLUSIONS: In more than one half of the patients studied early after heart transplantation, Intravascular ultrasound revealed epicardial atherosclerotic lesions which were incompletely identified by coronary angiography. The degree of atherosclerosis was closely related to donor age. The potential influence of donor transmitted coronary artery disease on the progression of transplant coronary artery disease requires further longitudinal studies.

Adult↗
PubMed1997

Recognition of acute cardiac allograft rejection from serial integrated backscatter analyses in human orthotopic heart transplant recipients. Comparison with conventional echocardiography.

BACKGROUND: Previous studies showed that moderate and severe acute cardiac rejection (AR) but not mild AR is associated with significant myocardial acoustic changes. This study examines whether serial measurements of end-diastolic two-dimensional integrated backscatter (2D-IB) enhance the diagnostic potential of ultrasonic tissue analysis in AR. METHODS AND RESULTS: Serial endomyocardial biopsies, conventional echocardiograms, and parasternal long-axis radiofrequency signals for determination of posterior wall and septal 2D-IB were performed in 52 transplant patients. Histology showed no AR in 155 biopsy samples, AR grade 1A in 25, AR grade 1B/2 in 27, and AR grade 3A/3B in 13. Whereas no significant 2D-IB changes occurred between AR-free studies and during AR grade 1A, posterior wall and septal 2D-IB increased during AR grade 1B/2 from -47.80 +/- 4.36 to -42.97 +/- 5.11 dB and from -36.72 +/- 7.45 to -32.52 +/- 7.98 dB (P < .001 and P < .05, respectively) and during AR grade 3A/3B from -47.96 +/- 4.74 to -38.25 +/- 5.32 dB and from -37.92 +/- 5.87 to -31.01 +/- 4.62 dB (P < .001 and P < .01, respectively). Changes in posterior wall and septal 2D-IB were greater during AR grade 3A/3B than during AR grade 1B/2 (P < .01 and P < .05). Increases of 1.5 dB in posterior wall or septal 2D-IB indicated AR grades > or = 1B with sensitivities of 88% and 83% and specificities of 89% and 85%; posterior wall and septal 2D-IB increases of 5.5 and 3.8 dB identified AR grades > or = 3A with sensitivities of 92% and 79% and specificities of 90% and 84%. Although a weak inverse correlation between posterior wall and septal 2D-IB changes and posterior wall and septal thickening (r = .41 and r = .39, both P < .001) and fractional diameter shortening (r = .35, P < .001) was found, significant 2D-IB increases also occurred in some rejecting patients with unaltered contraction. CONCLUSIONS: Increases in end-diastolic posterior wall and septal 2D-IB in serial studies permit reliable identification not only of moderate and severe AR but also of mild AR. Because 2D-IB increase significantly more in AR with myocyte damage than without such damage, an estimate of AR severity appears feasible. Significant myocardial acoustic changes during AR may occur independently of changes in contractile performance.

Acute Disease↗
PubMed1997

[Quantitative dobutamine stress echocardiography in follow-up of heart transplantation: normal values and findings in patients with transplant vasculopathy].

Cardiac allograft vasculopathy (CAV) remains a major problem after heart transplantation. This prospective study was performed to analyze the value of quantitative dobutamine stress echocardiography for the diagnosis of CAV compared with coronary angiography and intravascular ultrasound (IVUS). In 80 patients late (> or = 12 months) after cardiac transplantation, a total of 144 studies were evaluated. In addition to the usually performed regional wall motion analysis of 2D-echocardiograms, systolic thickening of septum and left ventricular posterior wall was quantified by M-mode echocardiography. In patients with CAV by invasive angiography and/or IVUS, systolic thickening of the septum and posterior wall was significantly lower at rest and at maximum dobutamine infusion than in patients without CAV. From a subgroup of 23 studies in transplant recipients without TVP or other cardiac complications, normal values for the M-mode parameters were calculated. The lower limits were: systolic thickening of septum at rest, > 17.2%, at maximum stress, > 45.9%; systolic thickening of left ventricular posterior wall at rest, > 41.6%, at maximum stress, > 67.6%. Regional wall motion analysis of 2D-echocardiograms had a sensitivity of 76% (specificity 82%) for diagnosis of CAV defined by invasive methods, evaluation of wall thickening by M-mode alone had a sensitivity of 63% (specificity 76%). The combined 2D- and M-mode-echocardiographic analysis yielded a sensitivity of 85% (specificity 71%). In summary, dobutamine stress echocardiography is a useful method for the noninvasive diagnosis of CAV. The quantitative M-mode analysis improves the sensitivity of the 2D-analysis. The calculated normal values for the M-mode parameters in heart transplant recipients may serve as reference for other studies.

Adult↗
PubMed1996

Dobutamine stress echocardiography for noninvasive diagnosis of cardiac allograft vasculopathy: a comparison with angiography and intravascular ultrasound.

This study was performed to assess the value of dobutamine stress echocardiography for noninvasive diagnosis of cardiac allograft vasculopathy (CAV) compared with coronary angiography and intravascular ultrasound (IVUS) in 50 consecutive orthotopic heart transplant recipients. In 46 of 50 patients, a technically adequate echocardiogram could be obtained. Using a 16-segment model, a total of 675 segments were analyzed. At rest, wall motion abnormalities were found in 61 of 675 (9.0%) left ventricular segments in 15 of 46 patients. At maximal dobutamine stress, 103 of 675 segments (15.3%) had wall motion abnormalities (25 of 46 patients). Based on IVUS and angiographic findings, patients were allocated to 2 groups. Group I (n=18) had absent or only mild intimal hyperplasia (mean IVUS grade < or = 3.0 on a 6-grade scale). Group II (n=28) had moderate to severe intimal hyperplasia (mean grade > 3.0 with or without angiographic evidence of CAV. The prevalence of wall motion abnormalities was significantly higher in group II than in group I, both at rest (50 of 415 vs 11 of 270 coronary segments in 13 of 28 vs 2 of 18 patients) and during maximal stress (88 of 415 vs 15 of 270 coronary segments in 22 of 28 vs 3 of 18 patients). Quantitative M-mode echocardiography demonstrated decreased wall thickening in group II versus group I patients at maximal dobutamine dosage in the septum (48 +/- 18% vs 61 +/- 17%; p < 0.01) as well as in the left ventricular posterior wall (77 +/- 21% vs 96 +/- 21%; p <0.005). Regional myocardial dysfunction as assessed by dobutamine stress echocardiography was associated with IVUS evidence of moderate to severe intimal hyperplasia. Dobutamine stress echocardiography appears to be a feasible noninvasive method for detection of CAV in heart transplant recipients, which may reduce the need for routine coronary angiography.

Adult↗
PubMed1996

Doppler analysis of pulmonary venous flow profiles in orthotopic heart transplant recipients: a comparison with mitral flow profiles and atrial function.

Previous Doppler studies of transmitral flow profiles in heart transplant recipients suggested left ventricular (LV) diastolic dysfunction. The influence of left atrial filling and emptying on mitral Doppler profiles in heart transplant recipients has not been studied systematically. In the present study, pulmonary venous flow profiles, mitral flow profiles, left atrial area change and mitral annulus motion were analyzed in 20 orthotopic heart transplant recipient and 20 control subjects by transthoracic and transesophageal echocardiography and Doppler. Mitral flow profiles revealed a "restrictive" pattern with a high early-to-late diastolic flow velocity ratio in transplant patients (2.16 +/- 0.52 vs. 1.30 +/- 0.25, p < 0.0001), which was mainly due to a reduced late diastolic maximum mitral flow velocity (32.6 +/- 8.3 vs. 51.6 +/- 12.4 cm/s, p < 0.0001). Left atrial area change (35.9 +/- 13.9 vs. 58.1 +/- 17.0%, p < 0.0006) and mitral annulus motion (9.2 +/- 3.3 vs. 12.2 +/- 2.0%, p < 0.05) were reduced in transplant recipients, compared to controls. Pulmonary venous flow parameters in transplant recipients were markedly altered during systole, when pulmonary venous flow parameters are influenced primarily by atrial function rather than by diastolic LV properties: peak systolic flow velocity (45.5 +/- 8.2 vs. 62.3 +/- 14.0 cm/s, p < 0.001), maximum flow velocity ratio (0.87 +/- 0.19 vs. 1.45 +/- 0.33), time velocity integral of pulmonary venous flow during systole (9.3 +/- 2.3 vs. 17.1 +/- 4.0 cm, p < 0.001) and the systolic fraction of the time velocity integral (52.6 +/- 10.8 vs. 68.5 +/- 6.8%, p < 0.001) were lower in heart transplant recipients than in controls. These findings are compatible with atrial dysfunction and reduced mitral annulus motion. The results of this study indicate that LV diastolic dysfunction is not the only possible cause of altered transmitral Doppler profiles in heart transplant recipients. Atrial abnormalities represent a major contributing factor to altered mitral and pulmonary venous flow patterns. Analysis of transmitral Doppler profiles alone are therefore not adequate for analysis of diastolic LV function in heart transplant recipients.

Adult↗
PubMed1994

Simultaneous transesophageal echocardiography and atrial pacing: assessment of the functional significance of coronary artery disease before surgical treatment of an abdominal aneurysm.

Conventional active stress tests for the evaluation of coronary artery disease are not feasible for patients in whom a significant blood pressure increase during a stress procedure should be avoided, for example, those with a coexisting aortic aneurysm. Transesophageal echocardiography (TEE) with simultaneous atrial pacing is a new, highly specific, and sensitive stress technique for the detection of coronary artery disease. Furthermore, TEE can be performed safely with only mild blood pressure increases. Therefore in the present case report of a 70-year-old male, application of combined TEE and atrial pacing was used successfully to exclude the hemodynamic significance of a circumflex artery stenosis and avoided a significant blood pressure increase before surgical correction of an abdominal aortic aneurysm.

Aged↗
PubMed1994

[Echocardiographic texture analysis in detection of acute cardiac rejection after heterotopic cervical heart transplantation].

Experimental studies from our laboratory demonstrated that acute cardiac rejections (AR) are associated with an increase in myocardial echo amplitudes which correlate with the histologic severity of AR. The aim of the present study was to test whether AR-induced myocardial structural changes would also alter the spatial distribution of the myocardial echo amplitudes, assessed by echocardiographic texture analysis, and whether this method would improve the sensitivity of AR diagnosis. Echocardiographic LV long axis views were daily recorded in 12 dogs after cervical heterotopic heart transplantation (mean survival time: 16.1 days; immunosuppression: cyclosporine, azathioprine and prednisolone; AR treatment: pulsed steroids) under strictly standardized conditions and digitized into a 256 x 256 x 8 pixel matrix. Texture analysis using Co-occurrence- and Run Length Matrix was performed in 45 x 12 pixel-sized regions of interest (ROI) within the septum (VS) and posterior wall (PW) in end-diastole. Results obtained without AR were then compared with those during biopsy-proven mild, moderate and severe AR. Severe AR are associated with a significant increase in Co-occurrence Matrix parameters within the septum and posterior wall (Contrast: VS: 3.1 +/- 0.7 vs. 3.9 +/- 1.1, p < 0.05. PW: 1.8 +/- 0.5 vs. 2.3 +/- 1.0, p < 0.05. Variance: VS: 19 +/- 15 vs. 36 +/- 18, p < 0.05. PW: 11 +/- 6 vs. 21 +/- 8, p < 0.01). During mild and moderate AR no significant changes in texture measurements were found. Testing the influence of ROI placement on myocardial echo amplitude, texture measurements showed a high variability in comparison to mean gray level (up to 30% vs. < 5%).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Serial changes during acute cardiac allograft rejection: quantitative ultrasound tissue analysis versus myocardial histologic findings.

OBJECTIVES: The aim of this study was to assess 1) whether quantitative ultrasound tissue analysis by serial measurements of myocardial echo amplitudes can detect and monitor the onset and degree of acute cardiac rejection, as well as its resolution of acute rejection during treatment, and 2) whether changes in myocardial echo amplitudes are modified by repeat additional rejection episodes. BACKGROUND: Previous experimental studies, all involving heterotopic heart transplantation, have consistently shown reproducible alterations in myocardial echo amplitude during acute rejection episodes untreated by immunosuppressive agents. METHODS: Two-dimensional echocardiographic long-axis views were obtained daily under strict standardization in 12 dogs after heterotopic cervical heart transplantation (mean survival time 16.1 days) and digitized into a 256 x 256 x 8 matrix. Myocardial echo amplitudes were analyzed by gray level histogram statistics in regions of interest (45 x 12 pixels) within the proximal septum and posterior wall and correlated with the results of daily transmural myocardial biopsies. Maintenance immunosuppressive therapy consisted of cyclosporine, azathioprine and steroids. Additive steroids were given during acute cardiac rejection. RESULTS: All dogs experienced at least one moderate or severe episode of acute cardiac rejection. Successful resolution and repeat acute rejection were observed in three dogs. On 65 days, the left ventricular biopsy specimens showed no evidence of acute rejection. Mild acute rejection was present on 36, moderate on 29 and severe rejection on 40 days. End-diastolic mean (+/- SD) gray level increased progressively from 100.7 +/- 20.4 for no acute cardiac rejection to 113.8 +/- 23.1 for mild rejection (p = NS vs. no rejection) to 126.0 +/- 16.1 for moderate rejection (p < 0.01) and to 136.3 +/- 12.6 for severe rejection (p < 0.01). In each individual dog, a correlation between daily measurements of mean gray levels and histologic cardiac rejection grades was found (rmean = 0.80 +/- 0.14 [range 0.57 to 0.97], n = 12). In three dogs with transient complete histologic resolution of acute cardiac rejection, mean gray level did not return to values before rejection (108.0 +/- 15.4 vs. 87.2 +/- 8.4). The subsequent second episode of rejection was characterized by higher gray level values than those associated with the first rejection episode (141.3 +/- 14.4 vs. 124.3 +/- 20.9). CONCLUSIONS: Acute cardiac rejection is associated with a progressive increase in mean gray level. Changes in myocardial echo amplitudes in individuals may thus prove a useful tool for the noninvasive detection and monitoring of acute rejection. Increased mean gray level values after resolution of rejection may indicate persistent structural tissue abnormalities after rejection and demonstrate the need to define new baseline values after histologic resolution of an acute rejection episode.

Acute Disease↗
PubMed1993

In vivo quantification of myocardial echo intensity from logarithmically amplified, demodulated radiofrequency signals.

Clinical application of echocardiographic tissue characterization necessitates measurements through the chest wall. Different distances between transducer and myocardial region of interest result in variable attenuation effects. Therefore, meaningful comparisons of myocardial echo intensity measurements are difficult with current equipment. The present study aims at the quantification and compensation of depth-dependent attenuation effects. Ten normals, 14 patients with mild (n = 7) or moderate (n = 7) hypertensive left ventricular hypertrophy and 10 transplant candidates were examined. Gain-independent logarithmically amplified, demodulated radiofrequency signals of parasternal long axis cross-sections were digitized. Mean myocardial echo intensities were determined in septal and posterior wall regions of interest. The slope of attenuation was determined from these clinically obtained data by plotting the distances between transducer and regions of interest against myocardial echo intensities. An attenuation coefficient derived from this slope was used for compensation of the depth-dependent losses of myocardial echo intensity. Compared with normals, compensated mean myocardial echo intensities were significantly lower in mild or moderate hypertensive left ventricular hypertrophy, but showed no significant difference in transplant candidates. Despite several limitations, the method employed in this study appears to be a possible approach to in vivo quantification and compensation of attenuation.

Adult↗
PubMed1993

Cardiac function during graded bicycle exercise: Doppler-echocardiographic findings in normal subjects and heart transplant recipients.

Orthotopic heart transplantation results in altered atrial anatomy and denervation of the donor heart. To assess the impact of these sequelae on left ventricular filling and systolic performance, 16 heart transplant recipients and 10 normal controls were evaluated by Doppler echocardiography at rest and during graded bicycle exercise. Global and regional systolic ventricular allograft function was normal at rest and during exercise. Resting Doppler profiles demonstrated diminished atrial contribution to ventricular filling in transplant recipients. The response to dynamic exercise was different in both groups; controls increased heart rate, while mitral time-velocity integral was unchanged. Heart transplant recipients, in contrast, showed a blunted heart rate response and increased time-velocity integral. Atrial contribution to ventricular filling was not augmented during exercise as in normal controls. Alterations in transmitral flow profiles in heart transplant recipients do not necessarily reflect ventricular myocardial damage, but may be related to impaired atrial function.

Adult↗