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M Schwaiblmair

Publications and source records attributed to M Schwaiblmair.

At least 19 recordsLinked to original sources
PubMed2005

Human herpesvirus 6 in bronchalveolar lavage fluid after lung transplantation: a risk factor for bronchiolitis obliterans syndrome?

Bronchiolitis obliterans syndrome (BOS) is the limiting factor to long-term survival after lung transplantation. Previous studies suggested respiratory viral tract infections are associated with the development of BOS. To identify the impact of virus detection in bronchoalveolar lavage (BAL) fluid, we analyzed BAL samples from 87 consecutive lung transplant recipients for human herpesvirus (HHV)-6, Epstein-Barr virus, Herpes simplex virus 1/2, Cytomegalovirus, respiratory syncytical virus and adenovirus by PCR. Acute rejection, BOS and death were recorded for a mean follow-up time of 3.27 +/- 0.47 years. Results of PCR analysis and other potential risk factors were entered into a Cox regression analysis of BOS predictors and death. Only acute rejection was a distinct risk factor for BOS of all stages, death and death from BOS. HHV-6 was detected in 20 patients. Univariate and multivariate analysis revealed that HHV-6 was associated with an increased risk to develop BOS > orb = stage 1 and death, separate from the risk attributable to acute rejection. Identification of HHV-6 DNA in BAL fluid is a potential risk factor for BOS. Our results warrant further studies to elucidate a possible causal link between HHV-6 and BOS.

Adenoviridae Infections↗
PubMed2002

Bronchial epithelial cell B7-1 and B7-2 mRNA expression after lung transplantation: a role in allograft rejection?

Obliterative bronchiolitis is commonly interpreted as chronic rejection and involves the bronchial and bronchiolar epithelium. Upregulation of major histocompatibility complex (MHC) II on bronchial epithelial cells (BEC) had been hypothesised to be an important trigger of a bronchus directed rejection response. More recently, the additional expression of the costimulatory molecules B7-1 (CD80) and B7-2 (CD86) on antigen presenting cells were found to play an important role in the activation of T-lymphocytes in transplant rejection. The role of the expression of these molecules by BEC is unclear. BEC obtained by bronchial brushing and bronchoalveolar lavage fluid (BALF) cells from lung transplant recipients were studied and evaluated for messenger ribonucleic acid (mRNA) expression of B7-1 and B7-2 by semi-quantitative reverse transcriptase-polymerase chain reaction. Significantly elevated B7-1/glyceraldehyde-3-phosphate dehydrogenase (GAPDH) mRNA ratios were found in BEC from patients examined during the first 3 months after lung transplantation. Interestingly, in a small group of patients with bronchiolitis obliterans syndrome the B7-1/GAPDH and B7-2/GAPDH ratios were significantly elevated for BEC, whereas no differences were found for the BALF cells. In summary, B7 messenger ribonucleic acid expression by bronchial epithelial cells may play a role in (chronic) lung allograft rejection.

Adult↗
PubMed2001

Pressure-guided nonsurgical myocardial reduction induced by small septal infarctions in hypertrophic obstructive cardiomyopathy.

OBJECTIVES: We sought to assess the safety and efficacy of pressure-guided nonsurgical myocardial reduction (NSMR) with the induction of small septal infarctions in patients with hypertrophic obstructive cardiomyopathy (HOCM). BACKGROUND: Nonsurgical myocardial reduction has been shown to decrease left ventricular outflow tract (LVOT) obstruction and to improve symptoms in patients with HOCM. Infarct sizes differ considerably among studies published so far. METHODS: In 50 patients, the LVOT gradient was invasively determined at the time of the intervention, four to six months (n = 49) and 12 to 18 months (n = 25) after NSMR. New York Heart Association functional class and quality of life were assessed by using a standard questionnaire. Exercise capacity was tested by spiro-ergometry. Left ventricular (LV) mass was determined by electron beam computed tomography. RESULTS: Small septal infarctions (mean creatine kinase value 413 +/- 193 U/l) resulted in a sustained decrease in LVOT gradients, from 80 +/- 33 to 18 +/- 17 mm Hg after four to six months (p < 0.001, n = 49) and to 17 +/- 15 mm Hg (p < 0.001, n = 25) after 12 to 18 months. Nonsurgical myocardial reduction was followed by a decrease in LV hypertrophy, which was associated with a sustained increase in exercise capacity, as well as improvement in quality of life. CONCLUSIONS: Pressure-guided NSMR inducing small septal infarctions was sufficient to result in a sustained decrease in LVOT obstruction and to improve symptoms. The incidence of complications, such as complete heart block with necessary permanent pacemaker implantation (<10%), seems to be diminished by minimizing the infarct size.

Aged↗
PubMed2001

Role of brain natriuretic peptide in risk stratification of patients with congestive heart failure.

OBJECTIVES: Using a prospective study design, we assessed the value of brain natriuretic peptide (BNP) to identify patients with heart failure who have an increased risk of deterioration of their functional status. Furthermore, we examined the relationship between BNP and various clinical characteristics incorporated into an established survival model used for risk stratification. BACKGROUND: Prediction of the clinical course is a crucial part of the decision-making process about the adequate treatment strategy for patients with advanced congestive heart failure (CHF). Although laborious, multivariable indexes have been established for risk stratification, simple plasma BNP measurements may be as useful as prognostic indicators. METHODS: In 78 patients referred to our heart failure clinic, plasma BNP levels were compared with the results of a multivariable prognostic model. To assess the prognostic power of BNP, the clinical course of this cohort was monitored for a median follow-up period of 398 days. RESULTS: At study entry, plasma BNP and the heart failure survival score (HFSS) showed a significant correlation (r = -0.706). During follow-up, Kaplan-Meier estimates of freedom from clinical events differed significantly for patients above and below the 75th percentile concentrations of plasma BNP (p < 0.0001). Changes in plasma BNP were significantly related to changes in limitations of physical activity, as demonstrated by logistic regression analysis (chi-square statistic = 24.9, p < 0.0001). Proportional hazards analysis confirmed BNP as a powerful predictor of functional status deterioration (p < 0.0001). This prognostic information was as powerful as that derived from the multivariable HFSS. CONCLUSIONS: Measurement of plasma BNP concentrations might provide a useful and cost-effective screening tool that helps reduce the need and frequency for more expensive cardiac tests.

Activities of Daily Living↗
PubMed2001

Cellular chimerism of the lung after transplantation. An interphase cytogenetic study.

The present study evaluated the origin of endothelial and epithelial cells, as well as of lymphocytes and macrophages, after lung transplantation. Biopsy specimens from patients who underwent lung and heart-lung transplantation and received organs of sex-mismatched donors were studied by means of nonisotopic in situ hybridization with DNA probes of the X and Y chromosome. By means of monoclonal antibodies against leukocytes, T and B lymphocytes, and macrophages, the various infiltrating cell types were analyzed. In all allografted lungs, the endothelial cells and bronchial and alveolar epithelium retained the donor sex type. The lymphocytes of the donor were almost completely replaced by recipient cells 1 month after transplantation. Low numbers of alveolar macrophages of the donor were present during the entire period under study. Low numbers of donor lymphocytes and high numbers of donor alveolar macrophages in the allografted lung seem to be correlated with a worse clinical course.

Antibodies, Monoclonal↗
PubMed2000

Elevated levels of interleukin-8 and transforming growth factor-beta in bronchoalveolar lavage fluid from patients with bronchiolitis obliterans syndrome: proinflammatory role of bronchial epithelial cells. Munich Lung Transplant Group.

BACKGROUND: Obliterative bronchiolitis (OB), the most important long-term complication after lung transplantation, is thought to be a manifestation of chronic rejection within the airways, with the hallmarks inflammation and fibroproliferation. METHODS: To characterize the inflammatory process in the context of OB we quantified tumor necrosis factor-alpha, interleukin (IL)-8, IL-10, and transforming growth factor (TGF)-beta on the protein and mRNA level in bronchoalveolar lavage fluid samples obtained from patients with bronchiolitis obliterans syndrome (BOS) and without BOS. In addition, bronchial cells sampled by bronchial brushing were analyzed for mRNA expression. RESULTS: In respiratory epithelial lining fluid (ELF) from BOS patients the protein levels of IL-8 (52.4+/-22.2 vs. 4.4+/-0.9 pg/ml ELF, P<0.005) and TGF-beta (5.6+/-1.9 vs. 0.9+/-0.2 ng/ml ELF, P<0.005) were significantly elevated. In addition, bronchoalveolar lavage fluid cells of BOS patients showed increased expression of TGF-beta (1.13+/-0.44 vs. 0.45+/-0.16, optical density [O.D.]/O.D. glyceraldehyde-3-phosphate dehydrogenase [GAPDH], P=0.11) and IL-8 (0.25+/-0.13 vs. 0.09+/-0.03 O.D/O.D. GAPDH, P=0.53) without the differences reaching statistical significance. In contrast, IL-8 mRNA expression of bronchial cells was significantly higher in the BOS group (0.85+/-0.40 vs. 0.22+/-0.10 O.D./O.D. GAPDH, P<0.05). CONCLUSIONS: We assume that IL-8 and TGF-beta may act as key mediators for airway inflammation and fibroproliferation in the pathogenesis of OB, with bronchial epithelial cells serving as a relevant source of IL-8.

Adult↗
PubMed2000

Evidence for oxidative stress in bronchiolitis obliterans syndrome after lung and heart-lung transplantation. The Munich Lung Transplant Group.

Bronchiolitis obliterans syndrome (BOS) is the most serious long-term sequel of lung or heart-lung transplantation (H/LTX). Neutrophilia in the lower respiratory tract is a prominent feature of BOS. Because polymorphonuclear leukocytes (PMN) are capable of releasing large quantities of reactive oxygen species, we measured indicators of oxidative stress and glutathione levels representing antioxidant defense in H/LTX patients (HLTX, n=6; double-LTX, n=7; single-LTX, n=9). We analyzed 19 bronchoalveolar lavage (BAL) samples from 13 non-BOS patients (nine female, four male: age 39+/-4 years) and 17 BAL samples from nine BOS patients (five female, four male: age 33+/-2 years). PMN were the predominant BAL cell population in BOS (61.7+/-7.8% vs. 12.3+/-3.4%, P<0.001). Myeloperoxidase activity in the epithelial lining fluid and oxidized methionine residues in BAL-derived proteins were elevated in BOS (8.6+/-1.6 U/ml vs. 2.2+/-0.6 U/ml, P<0.01; and 12.6+/-1.1% vs. 7.7+/-0.8%, P<0.001, respectively). In addition, the concentration of reduced glutathione in epithelial lining fluid was decreased in BOS (162.6+/-20.1 microM vs. 345.8+/-57.1 microM, P<0.01), whereas the proportion of oxidized glutathione was increased (13.9+/-2.0O% vs. 6.7+/-1.2%, P<0.001). PMN, myeloperoxidase, and oxidized methionine residues were inversely correlated, whereas reduced glutathione was positively correlated with forced expiratory volume in 1 sec (P<0.05 to P<0.001). We conclude that excessive oxidative stress and a lack of glutathione are associated with BOS after H/LTX and may play relevant roles in the development of this disorder.

Adult↗
PubMed2000

Optimization and evaluation of the signal intensity change in multisection oxygen-enhanced MR lung imaging.

The behavior of the signal intensity in MRI of human lungs was investigated during inhalation of pure oxygen. Nine volunteers were examined, five using a breath-hold and four using a non-breath-hold technique. Four coronal slices were acquired in each volunteer using an inversion recovery turbo spin-echo sequence. The inversion time of the sequence was optimized for maximum contrast. Breathing of pure oxygen and room air was alternated in the volunteers. Breath-hold and non-breath-hold cases were compared. Breathing pure oxygen lead to a statistically significant signal intensity increase (up to 18%) compared to breathing room air. In addition, T(1) maps were acquired during breathing 100% oxygen and room air. Inhalation of pure oxygen reduced the mean T(1) time of the lungs from 1280 (+/-85) msec to 1224 (+/-139) msec without breath-hold and from 1219 (+/-176) to 1074 (+/-92) msec with breath-hold. Therefore, an optimized sequence and measurement protocol provided significant signal intensity changes utilizing 100% oxygen. Magn Reson Med 43:860-866, 2000.

Adult↗
PubMed2000

Incomplete sympathic reinnervation of the orthotopically transplanted human heart: observation up to 13 years after heart transplantation.

OBJECTIVE: Heart transplantation (HTx) is associated with autonomic denervation of the donor heart. Sympathetic reinnervation (RI) as defined by the presence of functional nerve terminals occurs only if sympathetic ganglia outside the heart are connected with nerve terminals in the transplanted heart. The purpose of this study was to define the incidence and functional consequences of RI over time after HTx. The activity and distribution of norepinephrine (NE) uptake sites were assessed by positron emission tomography (PET) imaging. Symptom limited exercise testing was performed by bicycle-ergometer. METHODS: Forty-seven patients (m:f=42:5, 47.6+/-8. 2 years, age range 27-65 years) were investigated between 2 months and 13.6 years after HTx using PET and the NE analogue C-11-hydroxyephedrine (HED). Tracer uptake was quantified using dynamic imaging protocols yielding regional HED retention fraction. A regional value above 7%/min (+/-2.5 SD above the mean value of denervated hearts) was considered evidence for RI. The functional significance of RI was investigated in 34 patients (m:f=30:4, 49. 3+/-8.4 age range 27-62 years) by symptom limited exercise testing. Cardiac catheterization was performed at the time of PET imaging. RESULTS: RI could not be assessed in the first year after HTx, in 11% in the second year and in 80% of the patients from the third year on. Retention values plateaued then. In all time intervals, beyond the third year, not reinnervated patients were found. RI remained incomplete and was always restricted to the anterior wall of the left ventricle. Extent of retention of the left ventricle revealed a large individual range up to 66%, averaging of 20%. Recipient age at the time of HTx, reinnervated patients were 5.5 years younger than not reinnervated ones, proved as the only significant influencing factor for RI (P<0.05). Dividing patients into scintigraphically reinnervated (n=20) and not reinnervated (n=14), reinnervated patients displayed during exercise a higher maximal heart rate (137+/-14 vs. 123+/-20/min, P<0.05), heart rate increase (40+/-15 vs. 28+/-13/min, P<0.05), max. oxygen consumption (1674+/-424 vs. 1279+/-308 ml/min, P<0.01) and anaerobic threshold (887+/-170 vs. 717+/-183 mlO(2)/min, P<0.01) than not reinnervated ones. A correlation between transplant vasculopathy and RI could not be demonstrated. CONCLUSION: ++: RI assessed by PET and the NE analogue HED is time dependent, incomplete, displays a typical pattern and demonstrates a broad individual spread. Furthermore, RI enhances functional parameters of exercise testing.

Carbon Radioisotopes↗
PubMed1999

Optimization of the immunosuppressive protocol after lung transplantation.

BACKGROUND: The successful use of tacrolimus (Tac)-based immunosuppressive therapy in organ transplantation and our own positive experience in heart transplantation led us to investigate regimens including this agent at our center for lung transplantation. METHODS: From 1991 to 1998, 86 patients underwent lung transplants at our center and 78 of them were included in this analysis. The first 34 patients were treated with cyclosporin (CsA), azathioprine (Aza), and rabbit antilymphocyte globulin; the subsequent 30 patients received Tac with Aza, and the most recent 12 patients Tac with mycophenolate mofetil (MMF). In addition, all patients received prednisone. RESULTS: The number of acute rejection episodes per 100 patient days was 1.5, 0.6, and 0.3 for three treatment groups, respectively. Similarly, the incidence of refractory acute rejection per 100 patient days was lower in both Tac groups (0.20, 0.03, and 0, respectively). Freedom from acute rejection was highest in the Tac-MMF group (P=0.0037 vs. Tac/Aza, P=0.0007 vs. CsA/Aza). Freedom from recurrent acute rejection was significantly higher in both Tac groups (P=0.027 Tac/ Aza vs. CsA/Aza and P=0.025 Tac/MMF vs. CsA/Aza). The incidence of infections per 100 patient days was similar (0.8, 0.5, and 0.8) in all three treatment groups, with a similar distribution of fungal, bacterial, and viral infections. Freedom from infection also showed no difference. The survival rate was significantly higher for the Tac population, with actuarial 1- and 3-year survival rates of 93% and 71%, compared with the CsA group (71% and 51%, respectively, P=0.04). Prevalence of renal dysfunction (creatinine >2.0 mg/ dL) was 18%, 13%, and 0% in the 3 treatment groups, respectively. The development of glucose metabolism disorders was lower in the CsA group than in the Tac-Aza group (15% vs. 27%, P<0.05). CONCLUSIONS: Tac-based immunosuppressive therapy results in a lower rate of acute rejection after pulmonary transplantation, with similar infection rates and a slightly higher incidence of new onset diabetes mellitus compared with CsA-based therapy.

Acute Disease↗
PubMed1999

[Pharmacological testing of the reversibility of increased pulmonary vascular resistance before heart transplantation with prostaglandin I2 (prostacyclin)].

An increased pulmonary vascular resistance (PVR) or an increased transpulmonary gradient (TPG) is a risk factor for increased 3-day and 3-month mortality after heart transplantation (HTx). The reversibility of increased PVR or TPG under pharmacologic testing is supposed to indicate a decreased probability of right ventricular failure/death after transplantation. We tested the response of an increased PVR (> 2.5 Wood units, WU) and/or of an increased TPG (> 15 mm Hg) in 29 right heart catheterizations (thermodilution catheter) of 23 patients (54 +/- 8 years, mean NYHA-class 3.1 +/- 0.6, ischemic n = 8, dilated cardiomyopathy n = 15). Increasing doses of prostaglandin I2 (PGI2, mean maximum dose 13.5 +/- 6.4 ng/kg/min) were applied stepwise over at least 10 min at the maximum dose level. We analyzed any dependence of the reversibility of PVR and TPG under prostaglandin I2 on hemodynamic values, echocardiographic parameters, demographic data, and laboratory findings. A decrease of PVR to a range usually accepted as no contraindication for HTx (< or = 4 WU) was found in each patient without symptomatic systemic hypotension during application of PGI2 (baseline value: 4.7 +/- 1.3 WU, during PGI2: 2.3 +/- 0.6 WU). An unresponsive, fixed increased PVR or TPG was not observed using PGI2. In 62% of investigations, both PVR and TPG decreased below 2.5 WU and 15 mmHg, respectively. The extent of reversibility of PVR and TPG was individually different and did not depend on the mean pulmonary artery pressure, mean capillary wedge pressure, cardiac output, mean systemic artery pressure or echocardiographic parameters (EDD, FS, ES-distance), sodium, urea or bilirubin levels, medication, age of the patients or the duration of the disease. The baseline PVR correlated inversely with its percentile value during PGI2 (r = -0.76, p < 0.05). In advanced heart failure, PGI2 decreases PVR in ranges of lower risk concerning orthotopic HTx, without causing an intolerable systemic hypotension. The individual extent of reversibility of PVR and TPG under PGI2 is not influenced by basic hemodynamic parameters or the patient's demographic profile.

Dose-Response Relationship, Drug↗
PubMed1999

Functional significance of cardiac reinnervation in heart transplant recipients.

BACKGROUND: There is accumulating evidence of structural sympathetic reinnervation after human cardiac transplantation. However, the functional significance of reinnervation in terms of exercise capacity has not been established as yet; we therefore investigated the influence of reinnervation on cardiopulmonary exercise testing. METHODS: After orthotopic heart transplantation 35 patients (mean age, 49.1 +/- 8.4 years) underwent positron emission tomography with scintigraphically measured uptake of C11-hydroxyephedrine (HED), lung function testing, and cardiopulmonary exercise testing. Two groups were defined based on scintigraphic findings, indicating a denervated group (n = 15) with a HED uptake of 5.45%/min and a reinnervated group (n = 20) with a HED uptake of 10.59%/min. RESULTS: The two study groups did not show significant differences with regard to anthropometric data, number of rejection episodes, preoperative hemodynamics, and postoperative lung function data. The reinnervated group had a significant longer time interval from transplantation (1625 +/- 1069 versus 800 +/- 1316 days, p < .05). In transplant recipients with reinnervation, heart rate at maximum exercise (137 +/- 15 versus 120 +/- 20 beats/min, p = .012), peak oxygen uptake (21.0 +/- 4 versus 16.1 +/- 5 mL/min/kg, p = .006), peak oxygen pulse (12.4 +/- 2.9 versus 10.2 +/- 2.7 mL/min/beat, p = .031), and anaerobic threshold (11.2 +/- 1.8 versus 9.5 +/- 2.1 mL/min, p = .046) were significantly increased in comparison to denervated transplant recipients. Additionally, a decreased functional dead space ventilation (0.24 +/- 0.05 versus 0.30 +/- 0.05, p = .004) was observed in the reinnervated group. CONCLUSIONS: Our study results support the hypothesis that partial sympathetic reinnervation after cardiac transplantation is of functional significance. Sympathetic reinnervation enables an increased peak oxygen uptake. This is most probably due to partial restoration of the chronotropic and inotropic competence of the heart as well as an improved oxygen delivery to the exercising muscles and a reduced ventilation-perfusion mismatching.

Adult↗
PubMed1999

Cardiopulmonary exercise testing before and after lung and heart-lung transplantation.

Heart-lung (HLT) and lung transplantation (LT) have been shown to be effective procedures for patients with end-stage cardiopulmonary disorders. As yet, few data exist on the exercise performance of patients before and after thoracic transplantation except with regard to 6-min walk tests. In this article we report cardiopulmonary exercise test results of lung and heart-lung transplant recipients in comparison with their pretransplant values. We studied 103 consecutive recipients of single-lung (n = 46), bilateral lung (n = 32), and heart-lung (n = 25) transplants. Cardiopulmonary exercise testing with a cycle ergometer was performed before and shortly after surgery. Before transplantation, all patients showed severe exercise intolerance and markedly impaired parameters reflecting cardiopulmonary function (e.g., work capacity: 20 +/- 11% predicted; oxygen uptake: 34 +/- 12% predicted; oxygen pulse: 50 +/- 18% predicted; functional dead space ventilation: 57 +/- 10% of minute ventilation; alveolar-arterial oxygen difference during exercise: 79 +/- 15 mm Hg). At 55 +/- 9 d after transplantation, transplant recipients reached maximum oxygen uptakes in the range of 22 to 71% of predicted values; the peak oxygen uptake was increased after transplantation (13.1 +/- 3.4 ml/min/kg versus 10.4 +/- 3.8 ml/min/kg; p < 0.001). Work capacity, oxygen pulse, tidal volume, and peak minute ventilation did not differ in patients following single- or double-lung tranplantation or HLT. Ventilatory factors did not appear to limit exercise capacity in any group. Despite the persistent limitations in aerobic capacity and work rate seen in many of the recipients, cardiopulmonary performance is reasonably well restored shortly after LT and HLT.

Adult↗
PubMed1999

Bronchiolitis obliterans syndrome after (heart-)lung transplantation. Impaired antiprotease defense and increased oxidant activity.

Increased numbers of neutrophils are a common finding in bronchoalveolar lavage fluid (BALF) samples obtained from patients after (heart-)lung transplantation [(H)LTX]. Since proteases and reactive oxygen species secreted by neutrophils are capable of causing substantial damage to the lung tissue if not counterbalanced by the antiprotease and antioxidant screen, we hypothesized that neutrophil products may play a role in the development of obliterative bronchiolitis (OB). A total of 72 BALF samples obtained from 33 patients after (H)LTX were evaluated. Sixteen of these patients were suffering from bronchiolitis obliterans syndrome (BOS) at the time of bronchoalveolar lavage (BAL). As a control, BALF samples from 17 healthy volunteers were analyzed. Anti-neutrophil elastase (NE) activity was quantified by a titration assay. Concentrations of alpha(1)-protease inhibitor (API), secretory leukocyte protease inhibitor (SLPI), NE-API complex, and myeloperoxidase (MPO) were measured by ELISA. Oxidized methionine [Met(O)] was quantified by high-performance liquid chromatography (HPLC). Epithelial lining fluid (ELF) from patients suffering from BOS showed significantly increased neutrophil counts, significantly elevated concentrations of NE-API complex and Met(O), and a significant decrease in the concentration of SLPI. Furthermore, a trend toward an increased NE activity and MPO concentration was observed. These findings suggest that neutrophils may be involved in the development of BOS.

Bronchiolitis Obliterans↗
PubMed1999

Lung function and cardiopulmonary exercise performance after heart transplantation: influence of cardiac allograft vasculopathy.

STUDY OBJECTIVE: The reduced exercise capacity observed in most patients after heart transplantation may be due to treatment with immunosuppressive drugs, deconditioning, cardiac denervation, and graft rejection. Cardiac allograft vasculopathy (CAV) is presently the major factor limiting long-term survival after transplantation. Little information is available with regard to the relationship between CAV and functional impairment in these patients. DESIGN: Prospective. SETTING: A university hospital and a large transplant center. PATIENTS: About 37+/-5 months (range, 2 to 137 months) after orthotopic heart transplantation, 120 patients underwent lung function testing, cardiopulmonary exercise testing, and right and left heart catheterization. Significant CAV was defined as a stenosis > or =70% or severe diffuse obliteration in any of the three main vessels. Group I (n = 28) had a significant CAV; group II (n = 92), without a remarkable CAV, was the control group. MEASUREMENTS AND RESULTS: Overall, the maximum heart rate was 86+/-2% of what was predicted, and the peak oxygen consumption was 18.8+/-0.7 mL/kg/min (64% of that predicted). Groups I and II did not show significant differences with regard to anthropometric data, hemodynamic measurements, or number of rejection episodes. Group I exhibited significant differences in maximum heart rate (120+/-5 vs. 134+/-3 beats/min; p<0.01), work capacity (47+/-5% vs. 59+/-3%; p<0.05), peak oxygen uptake (16+/-1 vs. 20+/-1 mL/min/kg; p<0.01), and functional dead space ventilation (31+/-2 vs. 26+/-1; p<0.01). Pretransplant status, etiology of heart failure, ischemic time, and the number of rejection episodes did not correlate with any exercise parameter. CONCLUSIONS: Following heart transplantation, patients with significant CAV show a diminished exercise capacity, a reduced oxygen uptake, and a ventilation-perfusion mismatch. Thus, CAV may be a major factor limiting exercise capacity in heart-transplant patients.

Adult↗
PubMed1998

Relations between cardiopulmonary exercise testing and quantitative high-resolution computed tomography associated in patients with alpha-1-antitrypsin deficiency.

High-resolution computed tomography (HRCT) can be used to diagnose and quantify emphysema noninvasively, as significant correlations have been found between the histological grade on resected lung specimens and quantified (q) computed tomography (CT). In this study, we performed thin section qHRCT in patients with severe hereditary alpha-1-antitrypsin (AAT) deficiency. AAT deficiency is the most common genetic cause of emphysema in adults, and exercise intolerance is the most disabling, distressing consequence of emphysema for the majority of patients. qHRCT was used to quantify precisely the alterations in the lung parenchyma due to pulmonary emphysema. Up until now, the important relationship between the severity of emphysema and the reduced exercise capacity has received little attention. Therefore the purpose of the study was to investigate the relationship between emphysema as displayed by qHRCT and cardiopulmonary exercise testing (CPX) in patients with severe cardiopulmonary impairment. - qHRCT was performed in 21 patients with homozygous AAT deficiency. CT scans were obtained at three spirometrically standardized levels at the carina and (5 cm above and below the carina). The mean lung density at 50% of vital capacity and a quantitative histogram analysis of the frequencies of CT values were determined. All patients underwent symptom-limited CPX to analyse simultaneously cardiovascular and ventilatory systems responses. - In all patients, qualitative CT assessment demonstrated panlobular emphysema with large and extensive areas of uniform low attenuation, characteristically with a lower-lobe distribution. Mean CT density values of the patients (-845 +/- 6.9 (mean +/- SEM)) were significantly correlated with work capacity (r = 0.55, p <0.01), oxygen-pulse (r = 0.54, p <0.01) and functional dead space ventilation (r = -0.54, p <0.01). Moreover, severe emphysema index (CT values below a threshold value of 950 HU) correlated positively with functional dead space ventilation (r = 0.60, p <0.01) and alveolar-arterial oxygen difference (r = 0.70, p <0.001). - These results clearly demonstrate that CPX parameters, indicating a disturbed pulmonary gas exchange and a ventilation-perfusion-mismatch during exercise, are significantly related to the extent of lung emphysema.

Adult↗
PubMed1998

[Virtual and three-dimensional bronchoscopy with spiral and electron beam computed tomography].

PURPOSE: To compare spiral computed tomography (CT) and electron-beam CT (EBT) for 3D and virtual CT-bronchoscopy. MATERIALS AND METHODS: 17 patients with various disorders of the tracheobronchial system were examined using fiberoptic bronchoscopy, spiral CT and EBT. 3D images were reconstructed from CT data sets using automated segmentation based on volume-growing methods. Surface-rendered, volume-rendered, and hybrid reconstructions were visualized in real time using a data helmet. RESULTS: All data sets could be processed to high-quality three-dimensional (3D) and virtual reconstructions. The reduction of motion artifacts due to shorter scan times made EBT data sets better suited for automated segmentation and less susceptible to motion artifacts. 3D and virtual reconstructions did not increase the diagnostic sensitivity of CT compared to axial reconstructions alone. CONCLUSIONS: Shorter scan times of CT imaging yield higher-quality 3D and virtual reconstructions. Modern reconstruction techniques are valuable visualization tools for select indications and are the prerequisite for future developments in computer-aided medicine.

Bronchial Neoplasms↗