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Biomedical subjects

R Brennecke

Publications and source records attributed to R Brennecke.

At least 19 recordsLinked to original sources
PubMed1992

[Acceptance of social security by the German population].

Against the background of persistent problems of financing and monitoring the system of social security as practised in the Federal Republic of Germany, empirical research into preferences and acceptance has gained increasing importance. The acceptance of social security by the population has been checked empirically by means of data of the Socio-Economic Panel. The following questions have been studied: Which degree of acceptance applies generally speaking to the existing system? Are there differences in respect of acceptance regarding the various subdivisions of social insurance and how are they to be explained? What are the conclusions that can be arrived on the basis of these results? Overall assessment of the indicators employed shows that on the whole a high degree of acceptance is accorded to the existing security system. It cannot be concluded from the results that a fundamental reorganisation of the entire system towards security mainly on the individual's own responsibility would be in accordance with the preferences of the great majority of the population. Reorganisation would have to reckon with a low acceptance level. However, the monthly contributions--especially in respect of sickness insurance--are considered to be too high by part of the population.

Germany↗
PubMed1991

[The effect of PTCA on clinical outcome in patients with coronary single vessel disease].

We evaluated a 3-year clinical follow-up in 53 patients with unsuccessful PTCA, due to failure to reach the lesion (control-group) in comparison to a "matched pairs" group of 53 patients, in whom PTCA had been performed (PTCA-group). There were no deaths in the PTCA-group compared to 3 deaths (5.7%) in the control-group (ns). Two patients (3.8%) and three patients (5.7%), respectively, suffered an acute transmural myocardial infarction during the follow-up period (ns). Coronary artery bypass grafting (CABG) had been performed in five patients (9.4%) following PTCA, and in 17 patients (32.1%) of the control-group (p less than 0.002). The overall rate of serious cardiac events (death, myocardial infarction or CABG) amounted to 13.2% (seven patients) in the PTCA-group and to 43.4% (23 patients) in the control-group (p less than 0.002). Only in the PTCA-group was a repeat PTCA performed in 15 patients (28.3%) with restenosis (p less than 0.00003). 35 of 53 patients in the PTCA-group (66%) and 27 of 50 survivors in the control-group were free of symptoms at the end of follow-up (ns). These results demonstrate that PTCA in patients with single-vessel disease is followed by a marked reduction of serious cardiac events, predominantly of bypass-operations, but the necessity of a second PTCA-procedure in case of restenosis has to be considered.

Angioplasty, Balloon, Coronary↗
PubMed1990

Analysis of risk factors for restenosis after PTCA.

To identify risk factors for restenosis, we evaluated data in 473 patients with single-vessel percutaneous transluminal coronary angioplasty (PTCA) and control angiography after 6 months. Restenosis, defined as (1) loss greater than 50% of the initial gain, and (2) stenosis greater than 50% was found in 138 patients (29.2%). Univariate analysis revealed eight factors related to restenosis: (1) duration of symptoms less than 1 month (P = 0.005), (2) unstable angina (P = 0.004), (3) high-grade stenosis before PTCA (P = 0.014), (4) large residual stenosis after PTCA (P = 0.001), (5) insufficient improvement of stenosis (P = 0.042), (6) prolonged single inflation time (P = 0.017), (7) prolonged total inflation time (P = 0.055), and (8) low inflation pressure (P = 0.028). Multivariate analysis revealed four factors significantly related to restenosis: (1) large residual stenosis after PTCA (P = 0.0001), (2) prolonged single inflation time (P = 0.0047), (3) unstable angina (P = 0.0127), and (4) high-grade stenosis before PTCA (P = 0.0179). Modification of procedural factors might be helpful to reduce the risk of restenosis after successful PTCA.

Aged↗
PubMed1990

Parametric assessment of myocardial perfusion during interventional cardiac catheterization by means of X-ray densitometry-short-and long-term results.

X-ray densitometric evaluation of digital subtraction angiocardiograms allows an assessment of myocardial perfusion by means of the parameter 'MEAN RISE TIME' (MRT), defined as the time from the onset of local myocardial contrast medium opacification to the point of maximum opacification. Best results are obtained when the response of that parameter is compared before and after stimulation of coronary flow by papaverine. A prolongation of this parameter, especially after papaverine, was indicative of an impairment of myocardial perfusion, when compared to the results of TL-201 scintigraphy. In 50 patients with single vessel coronary artery disease the results of MRT pre and post papaverine before and after coronary angioplasty, as well as after 6 months were evaluated for 204 post-stenotic regions-of-interest. Before angioplasty papaverine induced a significant prolongation of post-stenotic MRT was measured 2.3 s +/- 0.9 s vs 3.1s +/- 0.8s; p less than 0.01), while after successful angioplasty post-stenotic MRT was measured significantly shorter after stimulation of coronary flow (2.6s +/- 1.0s vs. 1.9s +/- 0.9s; p less than 0.01). This indicated an improvement in myocardial perfusion. Nevertheless, 16/50 patients still presented pathological results of post-stenotic MRT after papaverine, although angioplasty was regarded successful. These patients presented a markedly higher rate of restenosis (14/16 patients after 6 months), a higher rate of dissections at the dilation site and a higher rate of dilated vessels, supplying myocardial areas after a Q-wave myocardial infarction. Thus, these results demonstrate the additional information about the short-and long-term outcome of an angioplasty procedure by densitometric myocardial perfusion analysis.

Absorptiometry, Photon↗
PubMed1990

Short- and long-term outcome after PTCA in patients with stable and unstable angina.

Acute results and follow-up data over a period of 36 months after attempted PTCA in 406 patients with stable angina and 202 patients with unstable angina are reported. The rate of acute complications (death, myocardial infarction and bypass grafting (CABG) amounted to 1.5% in stable and 6.4% in unstable patients (P less than 0.005). Within the first week after PTCA a significantly lower percentage (1.7% vs 10.4%) of cardiac events (death, myocardial infarction, CABG and repeat PTCA) was observed in the stable group (P less than 0.001). During a 12-month follow-up period, another 16.3% of the patients in the stable group and 30.7% of unstable patients suffered a new cardiac event (P less than 0.001). The long-term follow-up of 36 months revealed no significant difference in the event rate between stable and unstable patients (5.4% in both groups). The cumulative rate of myocardial infarction within 3 years after PTCA was significantly lower (3.7% vs 9.4%) in the stable group (P less than 0.005). The cumulative mortality amounted to 3.0% in stable and 6.4% in unstable patients (P less than 0.05) and the incidence of repeated PTCA was 8.1% and 19.3% respectively (P less than 0.001). The crossover rate to CABG was 10.1% in stable and 17.8% in unstable patients (P less than 0.01). The total rate of any cardiac event thus amounted to 24.9% in stable and 53.0% in unstable patients (P less than 0.001) within a 3-year follow-up period. At the end of follow-up, 74% of the stable patients were asymptomatic, compared with 60% of unstable patients (P less than 0.01). 45% of the stable group patients and 28% of the unstable patients were not on antianginal treatment (P less than 0.01). We conclude that PTCA in unstable angina carries a markedly enhanced risk of acute complications and cardiac events in the early phase after PTCA. In the long run, patients with stable angina have a better quality of life with regard to medical treatment and angina symptoms.

Adult↗
PubMed1989

[Possibilities and limits of 2-dimensional echocardiography in quantitative image analysis].

By two-dimensional echocardiography left ventricular volumes can be measured and ejection fraction can be calculated. But volume and ejection fraction determination are combined with a systematic underestimation despite high correlation in comparison to "true volume", whereas cineventriculography systematically overestimates true volume. This echocardiographic methodological problem is related not only to tangential scanning but also to low lateral resolution yielding a reduced endocardial border delineation. Meanwhile, advanced transducer technology and digital imaging techniques with zoom and cineloop possibilities have improved endocardial border detection. In comparison to cineventriculography, volume determination by two-dimensional echocardiography has improved significantly in comparison to results in 1983; this improvement was mainly due to a better determination of endsystolic volume. Similarly, left ventricular contrast echocardiography using color coding with statistical analysis of digitized images enhanced the accuracy of analysis of global and regional left ventricular function. Transesophageal echocardiography will be used when there is reduced image quality of transthoracic echocardiography, for example, in obese patients or those with pulmonary emphysema or mechanical ventilation. Transthoracic echocardiography has become a routine method for assessing global and regional left ventricular function. Echoventriculography can be used in patients with renal insufficiency, anaphylactic reaction to contrast medium, and poor left ventricular function.

Algorithms↗
PubMed1989

[The status of echocardiography imaging].

After several decades of gradual technical improvement of echocardiographic imaging, these methods have now attained a level of performance that is not so much dictated by technical limitations as it is determined by constraints imposed by the underlying physical principles. Image quality of echocardiographic imagers is discussed in terms of the spatial, temporal, and graylevel resolution provided. The level of technical performance obtained recently improves essentially the clinical value of echocardiography. Application of contrast material requires new techniques of image display such as color superposition imaging. Image quality in Doppler or color flow imaging is essentially described in terms of spatial, temporal, and velocity resolution. Phantom studies are proposed for routine testing of the image quality provided by clinical echocardiographic instruments. We mention some expected developments concerning archival image storage and the integration of echocardiograms into cardiological databases or complete departmental information systems.

Echocardiography↗
PubMed1989

[Right heart ventriculography using Gelifundol].

Forty patients (14 women, 26 men, mean age 58 years) with suspected anomaly of the right heart and suspected tricuspid insufficiency or atrial septal defect were given four injections of Gelifundol in five-minute intervals via the right cubital vein. Before, during, and after each injection an echocardiogram was obtained (four-chamber-view). One subcostal view was recorded. Contrast echocardiograms were analyzed according to a subjective score scheme by two independent observers and by video-intensitometry. After injection of contrast medium no patient showed ECG changes, nor did any patient report side effects after the injection of Gelifundol. Concerning the subjective parameters there were no significant differences between both observers. Score points varied between 5.2 to 5.5, intensitometric maxima lay between 54.6 and 58.0 relative intensity units, and the half-time of the intensity maximum (T1/2) varied between 7.2 s and 8.1 s. There were no statistical differences between the two observers. In all patients a diagnotic improvement could be achieved. A tricuspid insufficiency which was not diagnosed in the native echocardiogram could be diagnosed in 13 patients with Gelfundol. Thus, Gelifundol seems well suited for the assessment of right ventricular lesions in man.

Adolescent↗
PubMed1988

[Current complication rate of percutaneous transluminal coronary angioplasty in stable and unstable angina].

During a four-year period (1983-1986) percutaneous transluminal coronary angioplasty (PTCA) was performed on 930 patients with stable or unstable angina with a mortality rate of 0.4%. A transmural myocardial infarct developed in 1.1% and 1.0% of patients required an urgent aorto-coronary bypass. Thus the total rate of severe cardiac complications was 2.5%. Compared with the years 1983-1985, there was in 1986 a significant fall in the number of deaths and of myocardial infarcts from 2.2% to 0.5% (P less than 0.05), while there was a nonsignificant increase in emergency coronary bypass surgery from 0.7 to 1.3%. Patients with unstable angina compared with those with stable angina had a significantly higher mortality rate (1.0% vs. 0.2%; P less than 0.05), incidence of infarction (2.0% vs. 0.6%; P less than 0.05), and emergency operations (2.0% vs. 0.5%; P less than 0.05). The total risk of a severe cardiac complication was 1.2% for stable and 5.2% for unstable angina (P less than 0.001).

Aneurysm↗
PubMed1988

Requirements on resolution of digital imaging equipment in the cardiac catheterization laboratory.

We evaluated the requirements on spatial resolution of digital imaging equipment in the cardiac catheterization laboratory. Fifty cinefilms of the heart as the biological object and one film of a lead-ladder-pattern as an objective test were used. The patient films were examined for the visibility of the left ventricular angiogram, coronary arterial tree, coronary artery lesions, branching of septal arteries and the number of septal arteries. All films were viewed three times: with a 625 line TV-system, with a 1249 line TV-system and with a cineprojector. It was found that two application areas with different demands on the spatial and temporal resolution can be distinguished: 1) low spatial resolution and high temporal resolution, e.g. left ventriculography; and 2) high spatial resolution and low temporal resolution, e.g. coronary arteriography. For the diagnostic assessment of the state of the coronary system, the spatial resolution provided by the 1249 line TV-system was sufficient. Exceeding this resolution by using cinefilm quality provided no additional diagnostic information. A frame rate lower than 50 frames per second for coronary arteriography seems possible.

Angiography↗
PubMed1988

The effect of balloon dilatation on post-stenotic myocardial perfusion before and after stimulation of coronary flow reserve: evaluation by the densitometric parameter 'mean rise time'.

From densitometric evaluation of digital subtraction cineangiocardiograms the parameter 'Mean Rise Time' (MRT), defined as the time from the onset of local myocardial contrast medium opacification to the point of maximal opacification can be derived; this parameter revealed a close correlation with the results on myocardial perfusion obtained by Thallium-201 scintigraphy. A prolonged 'Mean Rise Time' was indicative of an impairment of myocardial perfusion. We have developed a heart-phase gated real-time digitization procedure and computer-supported method for the densitometric estimation of the MRT to obtain information about the effect of coronary balloon dilatation on myocardial perfusion before and after stimulation of coronary flow reserve by Moxaverin. In 22 patients with single vessel coronary artery disease Moxaverin caused a significant prolongation of the post-stenotic MRT (2.3 +/- 1.2s (mean +/- s.d.) vs. 2.9 +/- 1.1s, p less than 0.05), while after successful dilatation of the obstructive lesion a significant shortening of the MRT was found after stimulation of the coronary flow reserve (2.5 +/- 1.2s vs. 1.9 +/- 0.9s, p less than 0.05). A highly significant decrease in MRT after Moxaverin was measured post-dilatation in comparison to the initial pre-dilatation results (2.9 +/- 1.1s vs. 1.9 +/- 0.9s, p less than 0.005); this shows that the effect of successful balloon dilatation on the post-stenotic myocardial perfusion can be described very well by this parameter. These results demonstrate that information about post-stenotic myocardial perfusion during interventional heart catheterization can be obtained from digital densitometry.

Adult↗
PubMed1988

[Social medicine in the curriculum of universities of West Germany. Recommendations for developing topics and organization].

At German universities and colleges social and community medicine is mainly taught by lecturers from various medical fields. Accordingly a great variety of topics are presented and different focuses are set. Thus orientation becomes more difficult for the students. The present paper was elaborated by experienced lecturers. It contains proposals for the organization of the lessons. With regard to the topics a list of priorities is presented and criteria for the qualification of the lecturers are formulated.

Curriculum↗