Showing papers by "Marieke D. Spreeuwenberg published in 2008"

Exercise Testing to Estimate Survival in Pulmonary Hypertension

Abstract: Background: The 6-min walk distance (6MWD) predicts survival in pulmonary hypertension (PH). The peak oxygen consumption (V[spacing dot above]O2peak) measured during a cardiopulmonary exercise test (CPET) also relates to survival in PH, and it is unknown how the prognostic information from measurements of ventilatory responses and gas exchange during CPET compares to the prognostic information obtained by the 6MWD alone. The aims of our study were to compare prognostic values of different exercise parameters in PH and to assess whether CPET adds prognostic value to the information from the 6MWD. Methods: After baseline right-heart catheterization and exercise testing, survival was assessed in a cohort of 115 PH patients. Results: During the 4 yr of follow-up, 18 patients died. At baseline, pulmonary arterial pressure was 49 +/- 17 mm Hg, the slope relating minute ventilation to carbon dioxide output (V[spacing dot above]E/V[spacing dot above]CO2slope) = 45 +/- 11, V[spacing dot above]O2peak = 15 +/- 6 mL[middle dot]kg-1[middle dot]min-1, increase in O2 pulse from rest to peak exercise ([DELTA]O2 pulse) = 5 +/- 2 mL[middle dot]beat-1, and 6MWD = 445 +/- 128 m. For the prediction of mortality, the areas under the receiver operating curves were very similar for the different parameters and ranged from 0.69 to 0.74. Patients with a V[spacing dot above]E/V[spacing dot above]CO2slope 13.2 mL[middle dot]kg-1[middle dot]min-1, [DELTA]O2 pulse > 3.3 mL[middle dot]beat-1, or a 6MWD > 399 m had a higher cumulative survival (P < 0.05). Multivariable Cox regression with a forward selection procedure showed that only [DELTA]O2 pulse improved the univariate 6MWD prediction model significantly (P < 0.05). Conclusion: CPET parameters predict survival in PH patients and add marginally to the prognostic value of the 6MWD.

A systematic analysis of the feasibility of four-dimensional ultrasound imaging using spatiotemporal image correlation in routine fetal echocardiography.

Abstract: Objectives To investigate the feasibility of incorporating spatiotemporal image correlation (STIC) into a tertiary fetal echocardiography program. Methods During the study period all pregnant women fitting our inclusion criteria were enrolled consecutively. Four sonographers participated in the study, one of whom had substantial previous experience of STIC volume acquisition and three of whom did not. STIC volumes were acquired within the time slot allocated for the usual examination and all attempts were recorded. STIC volumes were assessed on acquisition conditions, the quality (as defined by a checklist of cardiac structures that could be visualized), and the rendering abilities. Furthermore, possible learning effects and the influence of experience with STIC on volume acquisition were studied. Results STIC volume acquisition was successful in 75.7% (112/148) of cases in which it was attempted. The more experienced sonographer had a higher success rate in STIC volume acquisition (experienced vs. less experienced, 88.4% vs. 70.5%, P = 0.02). Of all analyzed STIC volumes, 64.8% were of high or sufficient quality. STIC volume quality and rendering ability correlated strongly with the acquisition conditions. High-quality STIC volumes successfully rendered the intracardiac septa in 84.6% of cases. The coronal atrioventricular plane was rendered in 12/26 cases (46.2%). Conclusions This study shows that incorporation of STIC volume acquisition into the daily practice of a tertiary fetal echocardiography program is feasible. Sonographers do not have to be specifically experienced in three- or four-dimensional ultrasound imaging to acquire high-quality STIC volumes. For successful STIC acquisition and subsequent successful analysis, correct acquisition conditions are of major importance. Finally, our results demonstrate that STIC is as susceptible as conventional two-dimensional ultrasound imaging to individual variations and limitations in scanning windows. Copyright © 2008 ISUOG. Published by John Wiley & Sons, Ltd.

Reproducibility of Tumor Perfusion Measurements Using 15O-Labeled Water and PET

Abstract: PET and 15O-labeled water (H2 15 O) can be used to noninvasively monitor tumor perfusion. This allows evaluation of the direct target of antiangiogenic drugs, that is, tumor vasculature. Because these drugs often result in consolidation rather than regression of the tumor mass, a change in perfusion might be a more sensitive way to evaluate response than are indirect size measures on a CT scan. However, to use the technique for serial imaging of individual patients, good reproducibility is essential. The purpose of the present study was to evaluate the reproducibility of quantitative H2 15 O measurements.Methods: Nine patients with non– small-cell lung cancer (NSCLC) were scanned twice within 7 d and before any therapy. All H2 15 O scans were followed by an 18 F-fluorothymidine scan to allow for adequate volume-of-interest (VOI) definition. VOIs were defined using a 3-dimensional threshold technique. Tumor perfusion and the volume of distribution (VT) were obtained using a 1-tissue-compartment model including an arterial blood volume component and an image-derived input function. The level of agreement between test and retest values was assessed using the intraclass correlation coefficient (ICC) and Bland–Altman analyses. Possible dependency on absolute values and lesion size was assessed by linear regression. Results: All primary tumors and more than 90% of clinically suspected locoregional metastases could be delineated. In total, 14 lesions in 9 patients were analyzed. Tumor perfusion showed excellent reproducibility, with an ICC of 0.95 and SD of 9%. The VT was only moderately reproducible, with an ICC of 0.52 and SD of 16%. No dependency was found on absolute values of perfusion (P 5 0.14) and VT (P 5 0.15). In addition, tumor volume did not influence the reproducibility of perfusion (P 5 0.46) and VT (P 5 0.25). Conclusion: Quantitative measurements of tumor perfusion using H2 15 O and PET are reproducible in NSCLC. When patients are repeatedly being scanned during therapy, changes of more than 18% in tumor perfusion and 32% in VT (.1.96 · SD)

Membrane diffusion- and capillary blood volume measurements are not useful as screening tools for pulmonary arterial hypertension in systemic sclerosis: a case control study

Abstract: Background There is no optimal screening tool for the assessment of pulmonary arterial hypertension (PAH) in patients with systemic sclerosis (SSc). A decreasing transfer factor of the lung for CO (TLCO) is associated with the development of PAH in SSc. TLCO can be partitioned into the diffusion of the alveolar capillary membrane (Dm) and the capillary blood volume (Vc). The use of the partitioned diffusion to detect PAH in SSc is not well established yet. This study evaluates whether Dm and Vc could be candidates for further study of the use for screening for PAH in SSc.

227 Early detection of systolic and diastolic dysfunction in asymptomatic hypertrophic cardiomyopathy mutation carriers using cardiac magnetic resonance imaging

Abstract: Background Hypertrophic Cardiomyopathy (HCM) is characterized by asymmetric hypertrophy of the left ventricle (LV). While over 400 HCM mutations have been identified, increasing number of HCM mutation carriers without hypertrophy have been detected. No data on regional functional and structural abnormalities in HCM mutation carriers before the development of hypertrophy are yet available. With cardiac magnetic resonance imaging (CMR), both regional function and structure can accurately be evaluated.