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R Dörr

Publications and source records attributed to R Dörr.

At least 19 recordsLinked to original sources
PubMed1997

Impact of various compression rates on interpretation of digital coronary angiograms.

According to the ACC/ACR/NEMA/ESC-guidelines, digital techniques should be replaced by cinefilm for coronary angiography. The ad hoc group of experts recently chose CD-R (CD recordable) as transport media and the JPEG standard for image compression. To avoid a possible loss of image quality, the guidelines allow a maximal data compression of only 2:1. This, however, leads to a considerable limitation: coronary angiograms cannot be viewed in real-time directly from CD. Since the possible influence of higher compression rates on image quality of coronary angiograms had not been investigated in a controlled study, we evaluated 8 various compression rates (ranging from 5:1 to 43:1) according to a prospective, randomized and blinded protocol. Four independent observers assessed 1440 angiograms using a semiquantitative score. We found that angiograms with a compression rate of 5:1 and 6:1 did not lead to a clinically relevant deterioration of image quality, whereas 11:1 was still acceptable, but 43:1 becomes unacceptable. Since no clinically relevant loss of information at a compression rate of 6:1 was experienced in our study, a modification of the ACC/ACJ/NEMA/ESC-guidelines allowing higher compression rates should be considered.

Angiography, Digital Subtraction↗
PubMed1997

Sheath pulling immediately after PTCA: comparison of two different deployment techniques for the hemostatic puncture closure device: a prospective, randomized study.

Sheath pulling immediately after percutaneous transluminal coronary angioplasty (PTCA) increases patients' comfort, decreases burden for the medical staff, and may reduce hospital costs by shortening the length of stay. Immediate sheath pulling in anticoagulated patients with a low risk of bleeding complications is feasible using hemostatic devices. For the hemostatic puncture closing device (HPCD), published data regarding sheath pulling in patients immediately after PTCA is limited. Furthermore, no study addressed the question whether the recommended deployment time (DT) of 30 min can be reduced to a few minutes. We, therefore, performed a prospective study, randomizing 140 patients to a DT of 5 and 30 min, respectively. There were no statistical differences in gender, age, height, weight, or cardiovascular risk factors between the two groups. Blood pressures measured invasively immediately before sheath removal were comparable. Activated coagulation time just prior to sheath removal was 227 +/- 52 sec in the DT-5 group and 223 +/- 37 sec in the DT-30 group. After deployment, 74% of the DT-5 patients and 71% of the DT-30 patients showed immediate and complete hemostasis. The remaining patients showed only little oozing with complete hemostasis at the time of the final device removal. Hematoma size after 24 hr was 6.2 +/- 4.4 cm2 for DT-5 and 6.8 +/- 8.2 cm2 for DT-30 patients. There was no statistical difference between both groups. No severe bleeding or major complications were observed in either group. Thus, the use of a collagen system with an intra-arterial anchor (HPCD) is effective and safe when sheaths are pulled immediately after PTCA. The reduction of deployment time from 30 to 5 min is not related to an increased risk of bleeding or other vascular complications; patients can be transferred much faster to the ward, therefore reducing the burden on the personnel in the catheterization laboratory and increasing patients' comfort by allowing them to return to their rooms without a sheath.

Adult↗
PubMed1996

-Differential antithrombotic therapy in patients with low and high PTCA risk-.

Acute coronary occlusion as well as restenosis still represent the major limitations of coronary interventions. Either event seems to be related to thrombus formation. The purpose of this overview is to summarize the current status of the usefulness of conventional and newer antithrombotic drugs regarding the prevention of acute occlusion and restenosis (excluding stents). ANTICOAGULATION: For ethical reasons, no placebo-controlled studies were conducted to prove the usefulness of heparin in preventing acute occlusions. The dosage mostly used is 10,000 U, although a relationship between dosage and complication rate has not been documented. A prolonged heparin infusion in patients with low risk and uncomplicated PTCA has no advantages. Restenosis is not influenced by prolonged infusion of heparin or administration of coumadin as well. Low molecular weight heparin is currently under investigation. Hirudin and hirulog have shown promising results with less acute occlusions; however, their therapeutic range must be considered. ANTIAGGREGATION: In controlled studies, ASA significantly reduced acute occlusions during PTCA when given in addition to heparin. Ticlopidin is as effective as ASA, but due to its side effects should only be administered when contraindications to ASA exist. ASA significantly reduced restenosis in only 1 of 4 studies with limited number of patients. Thromboxane inhibitors such as ridogrel or clopidogrel showed promising initial results. Trapidil significantly reduced restenosis in 2 studies; quantitative stenosis analysis, however, was not performed. Inhibition of platelets by glycoprotein (GP) IIb/IIIa receptor antagonists represents an innovative therapeutic concept: numerous controlled trials have documented a significant reduction in cardiac ischemic events and therefore indirectly in restenosis rates. The recombinant monoclonal antibody c7E3 Fab seems to be more effective than the synthetic integrelin. Unfortunately, efficacy appears to be in direct relationship to the risk of bleeding complications. The clinical role of oral GP IIb/IIIa inhibitors has yet to be established. For patients with high risk PTCA, the use of hirudin instead of heparin as well as the addition of GP IIb/IIIa inhibitors should be considered.

Angioplasty, Balloon, Coronary↗
PubMed1996

[Waiting times and death on the waiting list for coronary artery bypass operation. Experiences in Munich with over 1,000 patients].

Short-term and long-term results are the classical parameters for quality assurance in coronary artery bypass graft surgery (CABGS). In contrast, waiting times and the inherent risks of waiting lists are usually neglected. Although the problem of "death on the waiting list" is generally known, related publications are scarce. Therefore, in January 1994, we started a prospective study to document the waiting times and the occurrence of severe complications in our patients waiting for CABGS. Between January 1, 1994 and July 31, 1996, we catheterized 1125 patients with indication for CABGS. 968 patients had social health insurance (SOCL); 157 patients were privately insured (PRIV). The urgency of CABGS was classified as "emergent", "ery urgent" and "less urgent" according to the clinical experience of the responsible cardiologists. All emergency cases could be operated the same day. 69% of the very urgent SOCL patients had to travel beyond the Munich area to be operated, while 84% of the respective PRIV patients were operated in Munich. SOCL patients were therefore separated from their families 4.3 times more frequently then PRIV. Not so urgent SOCL cases were separated from their families 1.8 times more often than PRIV. The mean waiting time for SOCL was 39.5 +/- 39.1 days in 1994, 34.9 +/- 31.5 days in 1995 and 22.7 +/- 16 days in 1996. The corresponding values of PRIV are 19.1 +/- 16.2, 19.8 +/- 14.1 and 17.2 +/- 12.6 days. The risk of dying while waiting for CABGS was 1.3% per month (15/1125). The reduction of waiting times by the factor of two between 1994 and 1996 did not, however, influence the death on the waiting list, because all deaths occurred within 4 weeks after diagnostic catheterization. Our results show that triage practices for patients requiring CABGS are not reliable. To minimize the risk of the "death on the waiting list", CABGS must be offered within a week after diagnostic coronary angiography, even for "elective" cases.

Adult↗
PubMed1995

Thyroid testing using the Cobas Core immunoassay system. A multicentre study.

The random access immunoanalyzer Cobas Core and the Cobas Core Thyroid Assays were assessed as to their clinical usefulness in the analysis of different thyroid diseases. Four centres participated in this study measuring the following five thyroid tests per sample on the instrument: thyrotropin, free thyroxine, thyroxine, triiodothyronine and free triiodothyronine. The assessment was based on studies of precision and clinical samples. Within- and between-series precisions showed a mean CV over all assays of 4.3 and 6.1%, respectively. Comparison of the test results with clinical data demonstrated that the Cobas Core results are in accordance with diagnosed thyroid diseases. A good discrimination between normal and disease status and between untreated and treated status was found. Furthermore, 370 sera measured with Technicon Immuno-1 TSH and FT4 assays were compared to the respective Cobas Core EIAs). A good correlation between the assays was demonstrated.

Evaluation Studies as Topic↗
PubMed1993

Evaluation of segmental elastic properties of the aorta in normotensive and medically treated hypertensive patients by intravascular ultrasound.

DESIGN AND METHODS: Local elastic properties of the descending aorta at different levels were evaluated by means of intravascular ultrasound images and pressure measurements. For this purpose, 30 normotensive patients and 30 age-matched medically treated patients with essential hypertension, all undergoing diagnostic cardiac catheterization, were studied. RESULTS: Hypertension was well controlled in the essential hypertensives (137.1 +/- 6.79/74.5 +/- 2.65 mmHg). Systolic but not diastolic blood pressure in the hypertensive patients was significantly different from that of the normotensives (118.8 +/- 4.38/69.7 +/- 1.65 mmHg). The continuous loss of volume compliance with increasing distance from the heart was significantly higher in the hypertensives than in the normotensive patients [normotensives (1.45 +/- 0.19) x 10(-10) m5/N at the thoracic aorta, (0.08 +/- 0.05) x 10(-10) m5/N at the external iliac artery; hypertensives (0.81 +/- 0.09) x 10(-10) and (0.05 +/- 0.01) x 10(-10) m5/N at the corresponding sites]. Similarly, the hypertensives had an elevated elastic modulus proximal to the aortic bifurcation compared with the normotensives (244.47 +/- 44.06 versus 108.10 +/- 17.76 m/s, respectively). The decrease in buffering function of the vessel at this site is presumably caused by a turbulent flow pattern. Compared with the normotensives, the treated hypertensives had a significantly higher elastic modulus at each site where this was measured, whereas volume compliance and sectional compliance were lower. CONCLUSION: The differences in elastic modulus and compliance between hypertensive and normotensive patients seem disproportionate to the difference in systolic blood pressure (within the normal range in both the treated hypertensives and the normotensives). Therefore, normalization of high blood pressure by long-term antihypertensive treatment may not fully reverse changes, caused by arterial hypertension, in the viscoelastic properties of the arterial wall.

Adult↗
PubMed1992

Fluorine-18 deoxyglucose PET for assessment of viable myocardium in perfusion defects in 99mTc-MIBI SPET: a comparative study in patients with coronary artery disease.

Extent and frequency of viable tissue in myocardial segments yielding a perfusion defect on technetium-99m methoxyisobutylisonitrile (99mTc-MIBI), single photon emission tomography (SPET) at rest was prospectively investigated with 2-18F-2-deoxyglucose (18FDG) positron emission tomography (PET) in 46 patients with chronic coronary artery disease (CAD). Of these, 43 had a history of old myocardial infarction. For comparative visual and quantitative evaluation of identical anatomical slices, PET image files were converted into the SPET file structure and into the same matrix size. SPET and PET images were documented and visually (9 segments/patient) or semiquantitatively evaluated by a target-like polar map. Relative perfusion was expressed in percentage of peak 99mTc-MIBI uptake. Sample 18FDG uptake was related to the 18FDG uptake in the area of such maximal perfusion (18FDG uptake was 100% at the 100% 99mTc-MIBI uptake area). Of 414 segments, 167 (40%) revealed a resting perfusion defect. 18FDG uptake was present in 38 (23%) of the defects, while another 40 (24%) segments yielded 18FDG uptake in the periphery of the defect. When grouped according to the degree of 99mTc-MIBI uptake-reduction (in percentage of peak activity), 80% of severe defects (less than or equal to 30% of peak uptake), 48% of moderate (31%-50% of peak uptake) and 31% of mild (greater than 50% of peak uptake) defects were considered as non-viable on the basis of 18FDG uptake. Complete viability was found in none of the severe defects in contrast to 29% of moderate and 35% of mild perfusion defects.(ABSTRACT TRUNCATED AT 250 WORDS)

Coronary Disease↗
PubMed1992

[Morphology of aortic isthmus stenosis--invasive study using intravascular ultrasound].

In patients with coarctation of the aorta, intravascular ultrasound can yield important additional diagnostic information concerning stenosis morphology and aortic wall structure that, thus far cannot be obtained with conventional angiography. For the first time, we were able to visualize, in vivo, the eccentric thickening of the posterior aortic wall, which is the typical morphological finding in patients with coarctation of the aorta, known from post mortem or intraoperative specimens. The additional information about stenosis morphology and aortic wall structure, obtained with intravascular ultrasound, is especially valuable for the newer interventional therapy of balloon angioplasty. With intravascular ultrasound, not only the direct quantitative assessment of the aortic cross-sectional luminal area, but also the immediate visualization of local dissections and aneurysms is possible. Using special angioplasty catheters with integrated ultrasonic crystals (which are currently under manufacturing development), a step-wise dilation with immediate evaluation of the therapeutical success may improve the short- and long-term results of balloon angioplasty. At present, intravascular ultrasound is still only an additional diagnostic tool. If it is combined with interventional balloon angioplasty, however, it could gain increasing clinical importance for the treatment of aortic coarctation in the near future.

Aorta, Thoracic↗
PubMed1990

Characterization of nuclear DNA in 12 species of Chlorella (Chlorococcales, Chlorophyta) by DNA reassociation.

Strains of 12 different species of the genus Chlorella were analyzed for amount, reiteration frequency and kinetic complexity of chromosomal DNA components by C0t analysis. The resulting C0t curves reveal at least two different DNA components consisting of single copy DNA (up to 95%) and of repetitive DNA with complexities of 4.1 x 10(3) base pairs (bp) to approximately 11.7 x 10(3) bp and a reiteration frequency of 100-760. The total amount of repetitive DNA is less than 9% of the nuclear genome and similar in all strains studied. In contrast, the total kinetic complexity varies in a wide range from 1.26 x 10(7) bp to 8.08 x 10(7) bp which is mainly due to differences in the size of single copy DNA. The genome sizes in Chlorella seem not to be correlated with biochemical and physiological characteristics and therefore are unlikely to be useful as a taxonomical marker. A comparison of thermal denaturation profiles showed that the melting points of repetitive and single copy DNA differ by approximately 7 degrees C which may result from base mismatch and/or from a distinct base composition of the repetitive DNA.

Cell Nucleus↗
PubMed1988

[Reocclusion following successful thrombolytic therapy in acute myocardial infarct].

Following successful reperfusion of the previously occluded coronary artery in acute myocardial infarction, reocclusion remains an at least partially unsolved problem. The literature reports figures between 10 and 30%. In the present study, 130 out of 543 patients with successful thrombolysis by means of intracoronary streptokinase underwent a follow-up angiography at the 3rd day (106/130, 80%) and/or 6 months (76/130, 59%) after the acute intervention. During the observation period, neither PTCA nor bypass surgery were performed. Reocclusion could be documented in 5.5% of patients at the early stage, and in 25.0% half a year later. In more than 75% of patients, who presented with a reoccluded infarct related artery, clinical evidence of reinfarction had been recorded during the follow-up period.

Coronary Circulation↗
PubMed1987

[Potentials of invasive cardiological diagnosis and therapy in West Germany. A comparison with other European states and the USA].

On the basis of a market analysis on the part of industry, the cardiological and cardiosurgical investigation and treatment capacities in 13 West European countries and in the USA are examined. With 2.0 adult left-heart catheter centers per million inhabitants or about 500,000 inhabitants per center, West Germany takes fourth place behind the USA (4.0), the Netherlands (3.2) and Switzerland (2.3). With regard to cardiac surgery, West Germany takes last place in the European comparison with less than 0.6 cardiac surgery centers per million inhabitants. The widespread use of transluminal coronary angioplasty (PTCA) is limited by the fact that only 28% of all cardiological centers in West Germany can ensure preparedness for emergency cardiac surgery operations in the same hospital. However, experience in the United States shows that less a proliferation of cardiac surgery centers than additional instruments and staff in the available facilities in West Germany would be desirable for economic and medical reasons.

Adult↗
PubMed1986

[Blood fibronectin changes in various neoplasms].

In 85 patients presenting with various cancers, changes in the frequencies of plasma fibronectin and of the carcino-embryonic antigen (CEA) were compared and the results were correlated with the degree of extension. Forty-six percent of patients with mammary adenocarcinoma had plasma fibronectin values higher than the age-related limit range, but only 18% had an increase in CEA. In patients with secondary metastases, the highest values were significantly different from those found in controls. In these cases, fibronectin was present in abnormal concentrations in more than 80% of the patients, and CEA in 50%. Positive fibronectin values were less frequent in other cancers, except those of the genital tract. Neither fibronectin nor CEA are organ-specific, yet these two tumoral markers differ in the frequency with which they appear, notably in patients with mammary carcinoma.

Adult↗
PubMed1985

[Intracoronary streptokinase in acute myocardial infarct. Experience with 461 patients].

Between March 1980 and July 1984, coronary angiography was performed on 461 consecutive patients (no age limit) with acute myocardial infarction, and the partially or completely obstructing thrombus lysed by selective intracoronary infusion of streptokinase. At the time of first coronary angiography 96 patients (21%) had a high degree of stenosis but no total occlusion of the infarct vessel (group A). In 365 patients (79%) there was complete occlusion which in 315 patients (86%) was removed successfully after an occlusion period of 213 +/- 87 minutes (group B). In 50 patients (14%) (group C) attempts at reperfusion failed. In 129 of 163 patients (79.1%) with one-vessel disease, PTCA (percutaneous transluminal coronary angioplasty) was successful. Patients with multiple-vessel disease and an occlusion time of less than four hours, on the other hand, were treated surgically within the first ten days (78 patients). In the remaining 254 patients conservative treatment was practised. Within the first 30 days there were seven deaths (14%) in group C, while among group A and B patients, under conservative treatment, 16 died (7.8%). After successful PTCA four patients (3.1%) died. The lowest mortality was among patients with a short occlusion time and early bypass operation (2.6%). The most frequent cause of death was cardiogenic shock (20 of 29 patients), more rarely ventricular fibrillation (3) or other causes (4). Ventricular rupture occurred in three patients, one of whom was saved by pericardial tap. One year later the mortality among the conservative group was 21.2%, after successful PTCA or bypass operation 9.3% and 6.4%, respectively.

Aged↗
PubMed1985

Sequential intervention procedures after intracoronary thrombolysis; balloon dilatation, bypass surgery, and medical treatment.

After successful intracoronary thrombolysis of an acute myocardial infarction in 145 patients subsequent intervention procedures were evaluated. In 48 of 62 patients (43%), percutaneous transluminal coronary angioplasty was performed successfully (success rate 77%), 41 patients (28%) were operated on and 56 patients (39%) were treated only medically. During the hospital phase in the angioplasty group, 4 reinfarctions were noted and 3 repeat angioplasties were required, while 41 of the 48 successfully treated patients (85.4%) remained clinically stable. In the surgical group, one cardiac failure occurred, while 40 patients (97.6%) were without cardiac event. In the medical group, 5 patients died (8.9%), 8 patients (14.3%) had a reinfarction, and 76.8% were clinically stable. During the follow-up period in the surgical group of 6 months 37 patients (90.2%) were clinically stable, all in functional classes I and II. In the angioplasty group 33 patients were stable (68.8%), and in the medical group 26 patients were stable (46.6%). In the whole group of 145 patients the hospital mortality together with that in the 6 months follow-up period was 9.7% with a reinfarction rate of 22.8%.

Adrenergic beta-Antagonists↗
PubMed1982

[Treatment of acute cardiac arrest. Observations in a cardiological intensive-care unit].

Between 1976 and 1980, 301 of 3106 patients in the cardiological intensive-care unit were treated for acute cardiac arrest (9.7%). As a result of better methods of prevention and the emergency doctor system, there has since 1968 been a 50% reduction in the number of cardiac arrests. Two-thirds of the patients were male, resuscitation was successful in 34% ("successful" means that the patient was transferred to a general ward from the intensive-care unit in a clinically and haemodynamically stable condition). The prognosis was better in those with posterior-wall myocardial infarction than in those with unstable angina, mitral-valve disease with congestive heart failure, and those with anterior-wall infarction, the latter generally being more extensive and thus in principle more dangerous than posterior-wall infarction. Cardiac arrest as part of cardiogenic shock proved irreversible in every instance. After three months the survival rate was 72%, after six months 66%, after one year 62% of all patients who had required resuscitation. They would not have been alive without intensive-care treatment. These figures contradict negative comments on the purpose and usefulness of cardiological intensive-care units.

Adult↗