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Biomedical subjects

Roland Hetzer

Publications and source records attributed to Roland Hetzer.

At least 91 records · Page 5Linked to original sources
PubMed2004

Factors excercising an influence on recovery of hibernating myocardium after coronary artery bypass grafting.

OBJECTIVE: Coronary artery bypass grafting (CABG) in patients with endstage coronary disease (CAD) significantly improves symptoms and prolongs life expectancy. Left ventricular function is also improved in some patients, but not in others. Factors which influence functional recovery of hibernating myocardium after revascularization are at present under investigation. METHODS: From 3/2000 to 8/2002, we analyzed 41 patients with an ejection fraction (EF) of < or =30%, who underwent CABG, prospectively. All patients received low-dose dobutamine echocardiography (DE), dobutamine myocardial scintigraphy with SPECT, dobutamine magnetic resonance tomography (MRI), contrast-enhanced MRI and, when necessary, positron emission tomography (PET). Hibernating myocardium (area of interest) was identified with these diagnostic tools preoperatively and biopsy samples were taken intraoperatively. RESULTS: All patients received complete coronary revascularization. Early mortality was 2.4%. Three patients died during follow-up. Six months after the operation DE, MRI and SPECT were repeated. EF increased in 23 patients (group I) by at least >or =5%, and in 14 patients (group II) it did not improve. The wall motion score in the area of interest had increased during preoperative DE in group I significantly. The score did not change in group II. In addition the diastolic-systolic wall thickness increase in the area of interest rose >15% during DE in group I preoperatively; the increase was < or =15% in group II. MRI hyperenhancement of the left ventricle was significantly lower in group I compared to group II preoperatively. SPECT showed myocardial viability in the area of interest in all 37 patients. There were no significant differences between group I and II seen in SPECT. When the area of interest was located in the anterior wall the patients more frequently showed ventricular improvement postoperatively than patients with an area of interest located in the inferior, lateral or posterior wall. Light microscopy showed more severe myocardial cell hypertrophy (>19 microm) and less severe destruction of myocardial cell architecture in biopsies of group I compared to group II (myocardial cell hypertrophy < or =17 microm). Electron microscopy showed mitochondrial abnormalities in size and shape, lack of contractile material and large areas containing nonspecified cytoplasm, lipid droplets, and large glycogen-filled regions, but no significant differences between the two groups. Gene expresssion of the pro-apoptotic genes BAK and BAX was lowered compared to expression in 'normal' myocardium. The anti-apoptotic gene BCL-XL was significantly more expressed in the 'area of interest' of group II patients than in group I patients. CONCLUSIONS: We conclude that in patients with endstage CAD myocardial recovery after coronary revascularization can be predicted using DE and MRI preoperatively. Myocardial regions without any potential of functional recovery show less adaptation (less pronounced myocardial cell hypertrophy), a more severe degree of myocardial architecture destruction and a higher degree of anti-apoptotic gene expression. We recommend a myocardial biopsy when DE and MRI are not favorable in a patient with end stage coronary artery disease referred to us with the option of heart transplantation or coronary bypass.

Adult↗
PubMed2004

Comparison of somatic development and status of conduit after extracardiac Fontan operation in young and older children.

OBJECTIVE: We set out to examine whether the extracardiac Fontan operation (ECFO) in young children is beneficial for the early postoperative course and whether it has a negative impact on the mid-term hemodynamics and growth of the children due to absent growth potential of the prosthetic conduit. Therefore we compared our medium-term experience with ECFO in children under 4 years of age to that in older children regarding the incidence of postoperative complications, somatomotoric development and conduit status. METHODS AND RESULTS: Between 11/95 and 12/02 ECFO was performed in 30 children under 4 years of age and 21 older children aged 4-13 years. There were no deaths in children under 4 years of age and two older children died. No prolonged support (>72 h) of suprarenin was required in small children compared to 4 older children. In twenty-seven children, who underwent postoperative heart catheterization no pulmonary artery or systemic vein distortion occurred. One re-operation and one transcatheter intervention were performed because of the partial conduit stenosis. During the median follow-up of 4.8 years a manifestly accelerated postoperative weight gain was observed in children operated on under 4 years of age, compared to that in older children (up to the 50 vs. 10th percentile, P<0.05). CONCLUSIONS: The ECFO could be performed in young children with low morbidity and mortality rates. In the majority of patients, implanted prosthetic grafts maintain stable form without the development of stenosis. Accelerated somatic development, especially in small children, is to be observed after completion of the Fontan circulation.

Adolescent↗
PubMed2004

Clinical results with an ePTFE inflow conduit for mechanical circulatory support.

BACKGROUND: Neurologic complication is an adverse event associated with mechanical circulatory support. To decrease the incidence of embolic cerebrovascular accidents (CVA) during support with the Novacor left ventricular assist system (LVAS), an expanded polytetrafluoroethylene (ePTFE) inflow conduit has been developed and introduced clinically. METHODS: Using clinical data from Europe and Canada, we conducted a retrospective analysis of the incidence of embolic CVA with the ePTFE inflow conduit (n=88) in comparison with the previously used polyester inflow conduits (n=310, including Vascutek n=155 and Cooley n=155). We calculated freedom from embolic CVA, risk reduction for embolic CVA, and linearized rates of embolic CVA. RESULTS: A significant decrease in the incidence of embolic CVA was demonstrated with the ePTFE conduit (ePTFE 10% vs polyester 23%, p=0.002). Kaplan-Meier analysis of freedom from embolic CVA at 180 days after implantation was 86% for the ePTFE group vs 72% for the polyester group (log-rank test, 0.0185). We also found an associated risk reduction of 55% in CVA occurrence in the ePTFE group when compared with the Polyester group (hazard ratio, 0.445; 95% confidence limit, 0.222-0.890; p=0.0221). Linearized CVA rates also were decreased at all time intervals after implantation in the ePTFE group. CONCLUSIONS: Preliminary clinical results with the newly introduced ePTFE inflow conduit provide compelling evidence that the ePTFE conduit material significantly decreases thromboembolic complications during mechanical circulatory support with the Novacor LVAS.

Adolescent↗
PubMed2004

Impact of donor-transmitted coronary atherosclerosis.

Because of the shortage of donor hearts, the criteria of an acceptable organ have been extended considerably over the past few years. This has increased the probability of the transmission of atherosclerotic lesions by means of transplantation. This study evaluated the extent to which pre-existing coronary atherosclerosis boosts the cumulative injury caused by brain death, ischemia, and reperfusion, and thus additionally impairs the outcome of transplantation.

Age Factors↗
PubMed2004

Transcontinental transport of a patient with an AbioMed BVS 5000 BVAD.

In patients with severe cardiogenic shock requiring implantation of a short-term assist device transportation to a specialized heart center for further therapy may be necessary. We report the first successful transcontinental air transport (from Singapore to Berlin, Germany) of a patient with fulminating myocarditis requiring implantation of a biventricular assist device.

Air Ambulances↗
PubMed2004

Non-specific removal of antibodies in patients with idiopathic dilated cardiomyopathy: implications for xenotransplantation.

We assessed the efficiency of non-specific extracorporeal immunoadsorption (EIA), using polyclonal anti-human immunoglobulin antibodies, in depleting the serum of anti-galactosealpha1,3galactose (Gal) antibody and in decreasing serum cytotoxicity in 5 patients with idiopathic dilated cardiomyopathy. The mean concentrations of anti-Gal immunoglobulin (Ig)M and IgG before EIA were 74 microg/ml and 159 microg/ml, respectively. After EIA, these concentrations decreased by 86% and 88%, respectively. Both anti-Gal IgM and IgG returned to pre-EIA concentrations within 1 month, without rebound to greater than baseline concentrations. After EIA, mean serum cytotoxicity also decreased from 90% to 17%, with recovery by 1 month. Extracorporeal immunoadsorption proved safe in patients with heart failure and was effective in depleting anti-Gal antibody and in decreasing serum cytotoxicity to pig cells.

Adult↗
PubMed2004

Quantitative analysis of right atrial performance after surgical repair of tetralogy of Fallot.

We aimed to assess the right atrial performance in patients after surgical correction of tetralogy of Fallot, and to clarify the relationship between the pump function of the right atrium and right ventricular systolic function. We included in the study 50 asymptomatic patients following corrective surgery of tetralogy of Fallot, comparing them to 30 normal subjects. Right atrial areas were measured by echocardiography, and the active fractional area of emptying was expressed, in percentages, as the area measured at the onset of atrial contraction, minus the minimal area, divided by the area at the onset of atrial contraction. We used this value to assess the atrial pump function. Right atrial peak strain rates were measured by tissue Doppler imaging. Compared to controls, patients with tetralogy of Fallot had a significantly reduced right atrial active fractional area of emptying (p = 0.005), along with a reduced peak late diastolic strain rate (p = 0.002). Among 20 patients who underwent magnetic resonance tomographic examination, a relatively higher right atrial peak late diastolic strain rate was shown in patients with a right ventricular ejection fraction of less than 50% (p = 0.021). Right atrial performance is reduced in patients after surgical correction of tetralogy of Fallot. When facing right ventricular systolic dysfunction, nonetheless, the right atrial pump function may be relatively enhanced. Tissue Doppler derived strain rate can provide quantitative analysis of regional right atrial performance.

Adolescent↗
PubMed2004

Nitric oxide inhalation modulates endothelin-1 plasma concentration gradients following left ventricular assist device implantation.

Inhaled nitric oxide (iNO) therapy is an effective treatment of pulmonary hypertension following left ventricular assist device (LVAD) implantation. As iNO may also modulate circulating endothelin-1 (ET-1) and big endothelin following LVAD implantation, we investigated the effects of iNO on ET-1 and big endothelin plasma concentration gradients. In order to assist weaning from cardiopulmonary bypass, iNO was administered to 15 consecutive patients with secondary pulmonary hypertension following implantation of a LVAD. Central venous, pulmonary arterial and arterial ET-1 and big endothelin plasma levels were measured preoperatively, on cardiopulmonary bypass prior to iNO administration, 12, 24 and 48 hours postoperatively, and 72 hours after weaning from iNO. The ET-1 gradients between central venous and pulmonary arterial plasma levels decreased significantly with time, and there was a trend for lower arterial-pulmonary arterial plasma concentration gradients. Big endothelin plasma concentration gradients were not altered significantly. The decrease in ET-1 plasma concentration gradients during and after iNO administration may reflect a restoration of the physiologic balance between the different vascular beds. This provides further evidence that intermittent iNO therapy may modulate ET-1 after LVAD implantation.

Administration, Inhalation↗
PubMed2004

Perfusion technique for nonhaemic cardiopulmonary bypass prime in neonates and infants under 6 kg body weight.

BACKGROUND: Cardiopulmonary bypass (CPB) in neonates and infants is associated with significant haemodilution when priming of the CPB circuit is accomplished without transfusion of homologous blood components. The degree of haemodilution and, thus, the requirements for blood transfusion may be reduced when the CPB circuit is miniaturized without compromising patient safety. METHOD: Between January 2002 and October 2003, selected neonates and small infants were operated on using a nonhaemic prime extracorporeal circuit. CPB priming volume could be reduced from 300 mL to 190 mL by using a dedicated neonatal CPB console with mast-mounted roller pump heads. Reduction of priming volume resulted from shortening of all CPB lines to the minimum, downsizing of all CPB lines, exclusion of unused CPB components, use of vacuum-assisted venous drainage and from close co-operation between the perfusionist, cardiac surgeon and anaesthesiologist. The reduction in priming volume was achieved without eliminating the arterial line filter as safety device. RESULTS: A total of nine patients weighing between 3.2 and 5.9 kg (mean 4.7 kg) and with a body surface area of 0.22-0.35 m2 (mean 0.29 m2) were operated on with the use of the modified neonatal CPB circuit and a nonhaemic prime. Bypass time varied from 38 to 167 min (mean 96 min). The mean haematocrit on CPB was 22.5% with a range of 17-29%. The postoperative course of all patients was uneventful. CONCLUSION: A significant reduction in CPB priming volume makes nonhaemic prime CPB in neonates and small infants undergoing complex repair of congenital heart defects possible.

Blood Transfusion, Autologous↗
PubMed2004

Dynamic high-resolution electron-beam CT scanning for the diagnosis of bronchiolitis obliterans syndrome after lung transplantation.

PURPOSES: To determine the diagnostic capabilities of dynamic high-resolution electron-beam (HREB) CT scanning for diagnosing bronchiolitis obliterans syndrome (BOS) in lung transplant recipients. MATERIALS AND METHODS: At the time of follow-up examinations after lung transplantation, 52 patients were examined by dynamic HREB CT scan. Visual signs of small airway disease were assessed and compared with lung function. For numerical analysis, the mean lung attenuation and its SD were determined and compared with the course of lung function tests. RESULTS: On visual analysis, significant parenchymal attenuation inhomogeneities were present in eight of nine patients with manifest BOS, and in two of four patients who developed BOS during follow-up. Thirteen of 20 patients with persistent normal lung function displayed homogeneous lung attenuation. On numerical analysis, mean lung attenuation was significantly lower in patients who developed BOS during follow-up than in patients with persistent normal lung function (both in expiration and inspiration, p < 0.0001). With an optimal threshold, the sensitivity was 100% (4 of 4 patients) and the specificity was 90% (19 of 20 patients). In patients with BOS at the time of the CT scan examination, parenchymal attenuation was less homogeneous than in patients with persistent normal lung function (p < 0.0001). With an optimal threshold, the sensitivity was 78% (7 of 9 patients) and the specificity was 85% (17 of 20 patients). CONCLUSIONS: Dynamic HREB CT of lung transplant recipients correlates well with lung function criteria of BOS at the time of the CT examination and with the subsequent progression to BOS.

Adolescent↗
PubMed2004

Factors influencing the results of double-valve surgery in patients with fulminant endocarditis: the importance of valve selection.

BACKGROUND: Extension of infection below the aortic valve is a serious complication, especially with mitral valve involvement. Mortality is substantial and reinfection can strongly influence outcome. PATIENTS: Of 327 surgical patients with active infective aortic valve endocarditis admitted to the Deutsches Herzzentrum Berlin for surgical treatment between December 1996 and December 2003, 108 had root abscess, and 53 (25.5%) had diagnoses of secondary infective mitral valve disease (SMVD). The mean age (+/-SD) was 53 +/- 14.2 years; there were 37 men and 16 women. METHODS: The secondary lesion on the mitral valve was classified as SMVD requiring double-valve surgery (DVS). This prospective clinical and echocardiographic study revealed 2 paths of infection extension into the mitral valve. In the DVS group, 38 patients (71.7%) had tissue metastatic lesions, and 15 patients (28.3%) had a jet lesion on the mitral valve. Most patients (42) with SMVD had an aortic ring abscess as the primary lesion. RESULTS: All patients with destructive endocarditic doublevalve disease received aortic and mitral valve surgery. In 19 cases (35.8%), mitral valve reconstruction was undertaken; in 4 cases, mitral valve replacement had to be carried out after attempted mitral valve reconstruction. Concomitant mitral valve replacement because of severe damage to the valvular and subvalvular apparatus was performed in 30 patients (56.6%). Other types of surgery performed in 11 cases (20.8%) were 8 closures of a septic ventricular septal defect and 3 closures of a fistula to the right ventricle or right atrium. Twenty-seven patients were treated with a Shelhigh prosthesis, 18 were treated with double-valve replacement (both Shelhigh), and 9 were treated with an aortic Shelhigh prosthesis and concomitant mitral valve reconstruction. Homografts were used in 17 patients, with mitral valve reconstruction carried out in 10 patients and a stented mitral prosthesis in 7. In 9 cases, 2 stented valve prostheses were used. There were 14 early (60 days) deaths (26.4%). Septic shock, severe annular and subannular destruction, and poor left ventricular function (end-diastolic dimension >65 mm, ejection fraction <40%) were the significant risk factors determined in the multivariate analysis. Function of Implants: Continuous and Color Doppler Investigation: Comparative studies of 2 different implants in the aortic position were performed late postoperatively (325 +/- 251 days) for homografts and the Shelhigh stentless prosthesis. The calculated instantaneous (maximal Doppler) gradient and the mean pressure gradient through the aortic implants were 19 +/- 10.4 mm Hg and 12 +/- 5.7 mm Hg, respectively, for the homografts and 24 +/- 8.4 mm Hg and 15 +/- 4.6 mm Hg, respectively, for the Shelhigh stentless prosthesis (not significantly different for the 2 groups). There was no mitral or aortic valve dysfunction. A trivial paravalvular leakage in the mitral position in 1 patient and a pseudoaneurysm of the left ventricular out- flow tract without leakage or valvular dysfunction in another were diagnosed by postoperative Doppler investigation. CONCLUSIONS: The mortality in patients with destructive endocarditis requiring DVS depends mostly on the patients' preoperative hemodynamic situation. The risk of reinfection can be minimized if valve substitutes are properly selected (homografts, Shelhigh No-React SuperStentless and No-React BioConduit in the aortic position, or Shelhigh BioMitral in the mitral position). Concomitant mitral valve reconstruction procedures do not increase the risk of mitral reinfection.

Endocarditis↗
PubMed2004

Changes in myocardial collagen content before and after left ventricular assist device application in dilated cardiomyopathy.

BACKGROUND: The purposes of this study were to confirm the changes in myocardial collagen level after left ventricular assist device (LVAD) support in dilated cardiomyopathy (DCM), find the relation between these changes and prognosis, and test a practical method to assess the level of myocardial collagen. METHODS: Left ventricular samples were collected from DCM patients with different prognosis (transplanted group n = 8, weaning group n = 10) at the time when the LVADs were implanted and again during cardiac transplantation (n = 8). The level of neutral salt soluble collagen (NSC) and acid soluble collagen (ASC) was measured by Sircol collagen assay, and that of total collagen and insoluble collagen (ISC) by quantification of hydroxyproline (Hyp). Serum samples were collected from a portion of these patients (transplanted group, n = 6; weaning group n = 7) at the time the LVADs were implanted, 1 month after implantation and on explantation. Circulating concentration of carboxy-terminal propeptide of type I procollagen (P I CP), amino-terminal propeptide of type I procollagen (P I NP), amino-terminal propeptide of type III procollagen (P III NP) and type I collagen telopeptide (I CTP) were measured by the equilibrium type radioimmunoassay. RESULTS: Before LVAD implantation the level of NSC and ISC in the weaning group was higher but ASC in the transplanted group was lower than in the controls (P < 0.05). After LVAD support, the level of total collagen was higher, but ASC was also lower in the transplanted group than in the controls (P < 0.05). In comparison of the pre- and post-LVAD subgroups of the transplanted and weaning groups, all collagen fraction levels before LVAD implantation were lower in the transplanted group than in the weaning group (P < 0.05); but this difference disappeared after LVAD support. Comparison of the pre- and post-LVAD subgroups of the transplanted group showed increased level of NSC and total collagen after LVAD support. The changes of serum peptide concentration showed that P III NP increased constantly in the transplanted group, but P I CP and P I NP increased in the weaning group after LVAD implantation. CONCLUSIONS: The changes in myocardial collagen level as a sign of myocardial interstitial remodeling in DCM are not involved with total collagen but involved with collagen fractions, and they are related to prognosis. The changes of myocardial collagen content and serum procollagen peptide after LVAD support can be regarded as an expression of the reverse of maladaptive myocardial interstitial remodeling.

Adult↗
PubMed2003

Cytomegalovirus infection status predicts progression of heart-transplant vasculopathy.

BACKGROUND: Transplant vasculopathy (TVP) is the most common cause of death and retransplantation after heart transplantation. Human cytomegalovirus (HCMV) infection has been linked to atherosclerosis and to the development of TVP. A prospective study evaluating the relation between CMV infection and progression of TVP is lacking thus far. The purpose of the present study was to investigate the influence of CMV infection status on the progression of TVP within 1 year. METHODS: We enrolled 103 consecutive heart-transplant recipients who underwent routine cardiac catheterization and intracoronary ultrasound examination at study entry and after 1 year. Plaque progression determined by quantitative intracoronary ultrasound was used to define the severity of disease at baseline and at 1-year follow-up. At study entry, HCMV infection status was evaluated by immunological assays and reverse-transcriptase polymerase chain reaction (RT-PCR). RESULTS: HCMV immunoglobulin (Ig)G/IgM seropositivity was found in 34 (33%) of transplant recipients, 11 of whom were HCMV PCR positive. The HCMV-positive group showed more advanced, calcified lesions (64.7% vs. 27.5%, P=0.002), and the maximal plaque thickness was significantly different from the HCMV IgG/IgM-negative group (median [quartile] 1.36 [0.85, 1.88] vs. 1.05 [0.58, 1.34], P=0.02). In a logistic regression model, we demonstrate that HCMV IgG/IgM positivity is a predictor for the progression of TVP independent of cardiovascular risk factors, inflammatory markers, and platelet activation (P=0.038). In addition, HCMV PCR positivity even increases the risk for accelerated TVP (P=0.017) and, consecutively, transplant failure. CONCLUSIONS: HCMV infection status in transplant patients detects patients with increased risk for transplant failure caused by TVP.

Cytomegalovirus Infections↗
PubMed2003

Modulation of circulating endothelin-1 and big endothelin by nitric oxide inhalation following left ventricular assist device implantation.

BACKGROUND: Inhaled nitric oxide (iNO) is an established therapy in the treatment of pulmonary hypertension and right ventricular dysfunction following left ventricular assist device implantation. Since it is known that endothelin-1 contributes to pulmonary hypertension, and nitric oxide modulates endothelin-1 synthesis in vitro, we investigated the effects of iNO on circulating endothelin-1 and big endothelin following left ventricular assist device implantation. METHODS AND RESULTS: On weaning from cardiopulmonary bypass, 15 consecutive patients with secondary pulmonary hypertension after implantation of a left ventricular assist device were treated with iNO. Endothelin-1 and big endothelin plasma levels were measured preoperatively, on cardiopulmonary bypass prior to iNO, 12, 24, and 48 hour postoperatively, and 72 hour after cessation of iNO. Endothelin-1 levels were increased preoperatively (1.05+/-0.20 fmol/L), and were highest on cardiopulmonary bypass (1.65+/-0.27 fmol/L). During iNO therapy endothelin-1 and big endothelin decreased significantly (endothelin-1: 12 hour 1.24+/-0.18, 24 hour 0.93+/-0.20, and 48 hour 0.81+/-0.14 fmol/L); they were lowest 72 hour post-iNO (endothelin-1: 0.56+/-0.09 fmol/L). Plasma endothelin-1 concentrations and iNO dose were inversely correlated (r=-0.657, P<0.015). A significant correlation was also found between endothelin-1 versus PA pressures and PVR/SVR ratio, but not with CI and SVR. CONCLUSIONS: Since it is known that endothelin-1 mediates pulmonary hypertension, we suggest a 2-fold effect of iNO therapy: firstly, a selective vasodilation of the pulmonary vasculature; and secondly, iNO mediated modulation of endothelin-1.

Administration, Inhalation↗