PubMed Health⌕ Search

Biomedical subjects

W Schiller

Publications and source records attributed to W Schiller.

8 recordsLinked to original sources
PubMed2005

Quantification of coronary artery stenosis with 16-slice MSCT in patients before CABG surgery: comparison to standard invasive coronary angiography.

OBJECTIVE: Invasive, selective coronary angiography is the gold standard for evaluation of coronary artery disease (CAD) and degree of stenosis. The purpose of this study was to compare 3-dimensional (3D) reconstructed 16-slice multislice computed tomographic (MSCT) angiography and selective coronary angiography in patients before elective coronary artery bypass graft (CABG) procedure. METHODS: Sixteen-slice MSCT scans (Philips Mx8000 IDT) were performed in 50 patients (42 male/8 female; mean age, 64.44 +/- 8.66 years) scheduled for elective CABG procedure. Scans were retrospectively electrocardiogram-gated 3D reconstructed. The images of the coronary arteries were evaluated for stenosis by 2 independent radiologists. The results were compared with the coronary angiography findings using the American Heart Association segmental classification for coronary arteries. RESULTS: Four patients (8%) were excluded for technical reasons. Thirty-eight patients (82.6%) had 3-vessel disease, 4 (8.7 %) had 2-vessel disease, and 4 (8.7%) had an isolated left anterior descending artery stenosis. In the proximal segments all stenoses >50% (56/56) were detected by MSCT; medial segment sensitivity was 97% (73/75), specificity 90.3%; distal segment sensitivity was 90.7% (59/65), specificity 77%. CONCLUSION: Accurate quantification of coronary stenosis greater than 50% in the proximal and medial segments is possible with high sensitivity and specificity using the new generation of 16-slice MSCTs. There is still a tendency to overestimate stenosis in the distal segments. MSCT seems to be an excellent diagnostic tool for screening patients with possible CAD.

Aged↗
PubMed2001

Young Investigator's Prizewinner 2001. Direct visualization of the influence of normothermic as opposed to hypothermic cardiopulmonary bypass on the systemic microcirculation in neonatal piglets.

The direct visualization of systemic microcirculation using intravitalmicroscopy permits the classification of proinflammatory and ischemic microvascular alterations during normothermic and hypothermic cardiopulmonary bypass in neonates. We used seven newborn piglets, on average aged 9 days, and weighing 3200g, as a control group. In addition, we studied nine piglets subjected to 60 minutes of constant nonpulsatile flow using hypothermic extracorporeal circulation at 28 degrees C, and five piglets using normothermic conditions at 37 degrees C. The microvascular network of the greater omentum and the subcutaneous tissue was directly visualized using intravitalmicroscopy. We analysed interactions between leukocytes and endothelial cells, microvascular morphology, and microrheological conditions, focussing on signs of ischemic and proinflammatory alterations. During normothermic cardiopulmonary bypass, the numbers of activated leukocytes were elevated compared to hypothermic cardiopulmonary bypass (p > 0.05). Arteriolar diameter decreased during hypothermia. Capillaries were markedly dilated during normothermia. Patterns of microvascular perfusion, for both types of cardiopulmonary bypass, showed signs of ischemic damage, revealed by a reduced functional capillary density. Perfusion dependent levels of lactate were higher during normothermic cardiopulmonary bypass (p > 0.05). This new experimental approach revealed that non-pulsatile cardiopulmonary bypass, independent of temperature, induces a proinflammatory and ischemic response compared to an unaltered control group. The markedly elevated numbers of activated adherent leukocytes, the reduced capillary density, and the high lactate levels in those undergoing bypass in normothermic conditions indicate a more pronounced inflammatory stimulus and tissue hypoperfusion compared to the possible protective effect of hypothermia for children undergoing cardiopulmonary bypass.

Animals↗
PubMed1999

Respiratory arousals in mild obstructive sleep apnea syndrome.

The objective of the study is to identify patients with mild sleep apnea by counting not only apneas and hypopneas, but also mild respiratory events, which do not fulfill apnea or hypopnea criteria, but result in an arousal (Type-R arousal). Arousals related to body movements (Type-M arousal) were separately counted. The influence of nasal continuous positive airway pressure (nCPAP) on respiratory and movement arousals was analyzed. Daytime sleepiness before and after nCPAP and its relationship to arousal types was investigated using the Multiple Sleep Latency Test (MSLT) and a standardised questionnaire. Twenty-two patients with a mean age of 43.6 +/- 9.2 years underwent polysomnographic evaluation on a baseline night, and during three nights with nCPAP. On the baseline night, subjects presented with a mean RDI of 10.5 +/- 7.2/h, an apnea index (AI) of 1.2 +/- 1.5/h, a hypopnea index (HI) of 9.3 +/- 6.6/h, a R index of 5.2 +/- 5.9/h, and a M index of 9.7 +/- 5.6/h. Use of nCPAP lowered the RDI (p < 0.001) and the R index (p < 0.01). Mean sleep latency in the MSLT increased with nCPAP (p < 0.05) and the patient's subjective well being improved (p < 0.01). Correlation analysis revealed a relationship between Type-R arousals and RDI and HI (r = 0.5, p < 0.01) as well as between questionnaire scores and mean sleep latency. The decrease of Type-R indicates the positive effect of nCPAP. Arousal analysis and detection of mild respiratory events associated with arousals are helpful in investigating the sleep structure and in objectifying clinical symptoms and treatment success in patients with mild OSAS.

Adult↗
PubMed1999

Economic evaluation of different minimally invasive procedures for the treatment of coronary artery disease.

OBJECTIVE: Several different techniques exist within the field of minimally invasive coronary artery surgery. In this study the impact of all these techniques on the total costs and economics has been evaluated. METHODS: Since May 1997, 121 minimally invasive direct coronary artery bypass (MIDCAB) procedures, 125 off-pump coronary artery bypass (OPCAB), ten Port-Access coronary artery bypass (PA-CABG) and 10 endoscopic coronary artery bypass grafting (ENDO-CABG) procedures were performed at our institution. A relative cost analysis of the different procedures was carried out in addition to a thorough evaluation done in five patients of each group dividing the costs into staff-related costs, material-related costs and general hospital costs. The costs were set in relation to regular CABG procedures. RESULTS: Specific less invasive coronary artery surgical techniques, such as the MIDCAB or OPCAB technique already are able to reduce the total costs when compared to regular CABG procedures. Within the Port-Access group as well as the ENDO-CABG group, increased material- and general costs are present when compared to regular CABG leading to increased total hospital costs for PA-CABG and Endo-CABG in Germany. CONCLUSION: At present, MIDCAB and OPCAB procedures are able to reduce total hospital charges, when compared to regular CABG procedures. Increased costs for Port-Access, as well as Endo-CABG surgeries may be compensated in the future by decreased costs due to a shorter phase of rehabilitation and faster return to regular professional activities.

Angioscopy↗
PubMed1982

[Comparison of commercially available radioimmunoassays for the determination of bile acids in serum (author's transl)].

Three commercially available radioimmunoassays for the determination of bile acids in serum were evaluated with respect to specificity and precision. The SLCG-radioimmunoassay (Abbott) measures chiefly cholic acid conjugates, and the CBA-radioimmunoassay (Becton-Dickinson) measures all conjugated bile acids, with an over-response to taurine metabolites. With respect to cross reactions, the performances of the CG-and the CBA-radioimmunoassays differed significantly from those stated by the manufacturers, the former showing a 32% response to taurocholic acid, the latter responding only 118% to taurochenodeoxycholic acid. At physiological concentrations of albumin + globulin, the recovery of defined cholanic acids was 85-101%. Good reproducibility was shown by the CG-radioimmunoassay in the range 0.5-10.0 mumol/l, by the CBA-radioimmunoassay in the range 1.0-25.0 mumol/l, and by the SLCG-radioimmunoassay in the range 0.5-3.0 mumol/l. There were no important differences in the inter-and intra-assay precision of the three methods.

Antibody Specificity↗