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Biomedical subjects

W Rafflenbeul

Publications and source records attributed to W Rafflenbeul.

At least 73 records · Page 4Linked to original sources
PubMed1984

[Progression of coronary sclerosis. Studies in 19 patients over a 6-year period using quantitative coronary angiography].

The characteristics of progressive coronary artery disease as judged from sequential angiography were quantitatively analysed in 19 patients with stable angina in whom coronary angiograms were repeated after 64-104 months (average 76.5 months). The diameters of at most 15 corresponding segments were measured with a vernier caliper (accuracy: 0.05 mm) at identical sites and in the same projections. Considering the error in measurement (less than 10%) and spontaneous changes in smooth muscle tone only a diameter decrease of greater than 20% and/or every transition to an occlusion were recorded as progression. The progression over a 6-year interval was predominately characterized by: A large amount of total occlusions (61% of all progressive stenoses), relatively independent of the initial degree of stenosis. A large amount of newly developed obstructions which are more severe in coronary arteries already segmentally diseased at the onset, indicating a diffuse intramural disease of the entire vessel. A different pattern of progression in the 3 main coronary arteries. No influence of risk factors on natural history.

Angina Pectoris↗
PubMed1984

[Progression and regression of coronary sclerosis in the angiographic image].

The natural history of coronary artery disease has to be studied by comparing coronary angiograms of the same patient taken at different times. However, conclusions from repeated angiographic studies are fraught with substantial errors mainly because of: 1. patients selection, 2. variable time interval and 3. technical pitfalls. Despite this bias published interval studies demonstrate that coronary atherosclerosis predominantly is a progressive disease: after 2-3 years 50% to 60%, after 3-4 years 60% to 70% and after 5 years more than 80% of patients demonstrate progressive coronary artery disease at angiography. In addition, quantitative evaluation of coronary angiograms reveals that progression of coronary artery disease: 1. has a variable pattern and pace in each coronary artery and 2. predominantly involves initially normal coronary artery segments. From all clinical and angiographic parameters under scrutiny progressive coronary artery disease is significantly correlated to: abnormal lipid levels at the time of the first angiogram, a period of unstable angina pectoris, interval myocardial infarction and initial severity of coronary artery obstruction. It has to be emphasized, however, that in the individual patient the speed of progression is highly variably supporting the concept of different underlying pathophysiological mechanisms (primary/secondary progression). Regression or coronary stenosis is a rare phenomenon which may occur spontaneously and is anecdotally reported in patients after vigorous treatment of severe hyperlipoproteinemia.

Angina Pectoris↗
PubMed1983

Quantitative coronary angiography: evidence of a sustained increase in vascular smooth muscle tone in coronary artery stenoses.

Quantitative analysis of coronary angiograms was performed to evaluate the effect of either 0.8 mg nitroglycerin (NTG, n = 54 stenoses) or 20 mg nifedipine (NIF, n = 42 stenoses) sublingually, or of both drugs combined (n = 50 stenoses) on coronary artery stenosis diameter. The narrowest diameter (DSTEN) in each stenosis was measured in multiple angiographic projections (2-7, mean: 4) before, and 10 min after administration of the drugs. Coronary artery stenoses were defined as concentric with DSTEN differing less than 25%, or as eccentric with greater than 25% in various projections. To establish the long-term effects of the vasodilator drugs measurements were repeated in 36 stenoses after an average 23-day interval in identical projections before and after NIF plus NTG sublingually. NTG dilated DSTEN from 1.19 mm to 1.53 mm (+28%) on average in 25 of 54 stenoses. After NIF, DSTEN increased in 20 of 42 stenoses from 1.21 mm to 1.59 mm (+31%) on average. The combination was most effective with DSTEN increasing from 1.24 mm to 1.85 mm (+49%) on average in 31 of 50 stenoses. The dilatory response was found to be related to stenosis morphology: lesions with an elliptical residual lumen responded significantly more often to NTG plus NIF than did lesions with a circular residual lumen; and of limited duration: interval angiography showed a restored increased vascular tone which could be released again with sublingual administration of NTG plus NIF.(ABSTRACT TRUNCATED AT 250 WORDS)

Coronary Angiography↗
PubMed1982

[The concept of "dynamic" coronary artery stenosis].

The present understanding of the pathogenesis of myocardial ischemia is primarily based on the concept of either a high-grade "fixed" coronary artery obstruction or a spastic vasoconstriction of an epicardial coronary artery. Both these mechanisms do not sufficiently explain the variable clinical syndromes of angina pectoris, particularly not the variation in anginal threshold experienced by many patients. Therefore, the concept of a variable vasoconstriction ("functional component") superimposed on an atherosclerotic lesion ("organic component") constitutes a plausible hypothesis connecting both pathogenetic mechanisms. The pathophysiological basis for this concept of "dynamic" changes in the degree of coronary artery stenosis, the clinical relevance and the therapeutical consequences are discussed.

Coronary Disease↗
PubMed1982

[Surgical revascularization in stenosis and occlusion of the left main coronary artery].

From 1975 through 1981 130 patients underwent coronary revascularization for significant stenosis or complete occlusion of the left main coronary artery (LMA). Hospital mortality was 4.6%, 3.3% were related to cardiac causes. The incidence of perioperative infarcts was 9.7%; in three fourths of these patients cardiovascular complications (e.g. hypertension, hypotension, arrhythmias) had occurred between start of anesthesia and start of extracorporeal circulation. Patients with a more than 90% LMA stenosis and complete occlusion of the right coronary artery appear to be at a particularly high risk both in terms of mortality and perioperative infarcts as compared to all other LMA-stenosis patients (operative mortality 15% vs. 3.5%, perioperative infarcts 15% vs. 8.8%). 3 patients with complete LMA occlusion did not suffer perioperative infarcts and survived in the long term. Follow-up investigation (mean 28.8 months) revealed late infarcts in 9 patients, 5 of which were lethal (late mortality 4.1%). Of hospital survivors, 88% were entirely asymptomatic or had very little angina pectoris (classes I and II NYHA). Cumulative survival was 84.3% at 5 years.

Angina Pectoris↗
PubMed1980

Dilation of coronary artery stenoses after isosorbide dinitrate in man.

The effect of isosorbide dinitrate (ISDN), 5 mg sublingually, on the diameters of coronary artery stenoses (n = 27) was examined in 20 patients. Another 18 patients with angiographically normal coronary arteries received the same amount of ISDN and were used as controls. Prestenotic and stenotic diameters were measured with a vernier calliper having an accuracy of 0.05 mm. The degree of stenosis was expressed as percentage of cross-sectional area reduction. ISDN caused uniform dilatation of every normal epicardial artery; mean increase in diameter was 21 per cent (range: 17 to 26%). In 18 stenoses (28 to 95% obstruction) there was very little change after ISDN. The mean prestenotic diameter increased from 2.82 +/- 0.48 mm to 3.05 +/- 0.43 mm and the mean stenotic diameter from 1.45 +/- 0.49 mm to 1.59 +/- 0.51 mm. However, in the nine other stenoses (35 to 89% obstruction) the mean degree of obstruction decreased significantly from 68 +/- 15.6 per cent to 47 +/- 15.6 per cent after ISDN. This improvement was a result of a significant increase of the mean stenotic diameter from 1.71 +/- 0.47 mm to 2.41 +/- 0.55 mm, whereas the prestenotic diameter showed only an insignificant increase from 3.17 +/- 0.63 mm to 3.31 +/- 0.58 mm after ISDN. In four patients with two obstructions in different coronary branches ISDN dilated one without significantly affecting the other lesion. From the data we conclude that ISDN can dilate some coronary artery stenoses but that this response may vary from one site to another even in the same patient.

Coronary Disease↗
PubMed1980

Quantitative difference in "critical" stenosis between right and left coronary artery in man.

Coronary artery stenoses that limit blood flow below demand are considered critical. In this comparative study we investigated whether the same degree of stenosis in either the proximal third of the right coronary artery (RCA) or the proximal third of the left anterior descending artery (LAD) causes critical flow reduction. Lesions were quantified from 35-mm cinefilms in multiple projections using a vernier caliper. These morphometric measurements were correlated with various manifestations of critical flow reduction, such as angina pectoris, development of collateral vessels and segmental wall motion abnormalities. In 13 patients with anginal pain and isolated RCA stenosis, the mean degree of obstruction was 63% area stenosis, which was significantly lower (p < 0.05) than that measured in 17 symptomatic patients who had isolated obstructions of the LAD (77% area stenosis). In patients with an identical degree of obstruction (78%) in either the LAD or RCA, collateral vessels were angiographically demonstrable in 53% of the RCA stenoses but in only 29% of the LAD stenoses. Furthermore, when the stenoses were less than 63% in the RCA and LAD, regional wall motion abnormalities were more frequently (p < 0.05) associated with RCA than with LAD stenoses. These observations indicate that a significantly smaller percent area of stenosis is critical in the RCA than in the LAD.

Arterial Occlusive Diseases↗
PubMed1980

[Coronary morphology in patients with unstable angina pectoris. Quantitative analysis of coronary angiograms before and after one year of medical treatment (author's transl)].

The purpose of this study was to quantify coronary morphology under medical therapy in patients with initially unstable angina pectoris (Propranolol, long-term nitrates). In 25 patients the extent of 69 coronary stenoses was exactly quantified with a vernier caliper (accuracy: 0.05 mm) in two successive coronary angiograms performed in each patient at approximately one year interval. The validity of the measuring technique was assessed in nine hearts in which 19 coronary stenoses were measured in the intravital coronary angiogram and then compared with the post mortem planimetric measurements of the same cross-sections after pressure fixation. This relation yielded a correlation coefficient of r = 0.87. In the patients with initially unstable angina the average degree of the stenoses in the three major coronary branches did not change significantly over the one year interval: In 27 stenoses of the right coronary artery the mean degree of obstruction averaged 79% in the initial angiogram and 84% in the second angiogram. In 26 stenoses of the left anterior descending artery the degree of obstruction was 78% and 77%, respectively and in 16 stenoses of the left circumflex artery 73% and 83%, respectively. Only 14 out of 69 stenoses (= 20%) showed a distinct progression of more than 20% area obstruction. All stenoses of 90% or more in the first angiogram (n = 6) progressed to complete obstruction within one year. In contrast, in five other stenoses we measured a regression in the degree of obstruction of more than 20%. We conclude from these quantitative measurements that the severity and the distribution of coronary lesions are similar in patients with stable or unstable angina pectoris. Coronary anatomy showed no significant change after one year of medical treatment in patients with unstable angina.

Angina Pectoris↗
PubMed1975

[Proceedings: Diagnostic value of myocardial perfusion scintigraphy in coronary sclerosis].

UNLABELLED: Perfusion scintigrams with Technetium-labeled microspheres were performed in 60 patients undergoing selective coronary angiography. The scintigrams were analyzed semiquantitatively with the aid of a computer. In addition, angiograms were quantitated with regard to proximal obstructions as well as regional wall changes of the left ventricle (VCF). RESULTS: 1. A reduction of scintigraphic activity was already seen in narrowings of lesser degrees (50%); 2. scintigraphic activity followed the degree of obstruction rather than the contraction abnormality. Perfusion scintigrams are helpful in selecting patients for revascularization.

Coronary Disease↗
PubMed1975

[The development of intramyocardial haemorrhages or fluidaccumulation in the extracellular space].

Isolated rat hearts according to Langendorff and rabbit hearts after orthostatic collapse were studied under the light and electron microscope. The light-micrographs were also quantitatively analysed. Changes in the vessels are noticeable, especially those in the sinusoid's. Vessel ruptures occur, also isolated endothelial ruptures with intact basement membranes and perfusion fluid enters the extracellular space. Numerous 0.06-01 mu large vesicles appear in the cytoplasma of the endothelial cells. A large number of vesiculation processes can be demonstrated along the cell membrane. The extracellular space is strongly-dilated. Changes in the colloid osmotic pressure and a rise in perfusion pressure have no clearly demonstrable influence on the extent of extravasation under the experimental conditions. The mechanism possible inducing such vessel changes is discussed.

Animals↗
PubMed1975

[Influence of acute preload changes on the mean velocity of circumferential fiber shortening of the left ventricle].

The cineangiographically determined mean velocity of circumferential fiber shortening (-vcf) has been used as a measure of basal cardiac contractility in man. In order to test the effect of acute changes in preload on -vcf, dextran was administered i.v. in steps of plus 2 percent, plus 4 percent and plus 6 percent of body weight to 8 closed-chest anesthetized dogs after minimizing cardiac reflex adjustments by 0.5 mg/kg propranolol i.v. and by cutting the vagi. -vcf, end-diastolic and end-systolic volume were estimated from left ventricular (LV) monoplane cinefilms in the right anterior oblique projection. At plus 2 percent and plus 4 percent of dextran -vcf remained unchanged as compared to control, i.e. after autonomic blockade. At plus 6 percent -vcf decreased significantly. LV max dP/dt increased significantly up to the step of plus 4 percent and decreased then slightly despite a further significant increase of LV end-diastolic pressure. In additional 6 dogs the largest volume load (plus 6 percent) was applied as the first step after control. Under these conditions there was no significant change in -vcf. In conclusion, -vcf appears to be essentially independent of changes in preload. Its usefulness as a measure of contractility is however limited by the negative inotropic effect of repeated injections of contrast dye.

Animals↗
PubMed1975

Angiographic determination of left ventricular muscle mass in the dog.

Left ventricular (LV) cineangiography in the right anterior oblique projection was carried out in 7 dogs. Calculation of LV muscle mass (LMM) was based on the determination of end-diastolic volume (EDV) and posterior wall thickness (h). Three different procedures of calculation were used. (A) EDV was determined according to the technique of Greene [8]; h was assumed to be equal around the LV cavity. (B) Systematic overestimation of EDV by Greene's method was corrected according to the regression equation proposed by Bentivoglio [9]; h was the same as in A. (C) EDV was corrected as in B; h at the ends of the long axis was assumed to be only half of that at the minor axis (i.e. h/2). The calculated values of LMM (4 to 11) in the individual dogs were averaged and compared with the true LMM determined at autopsy. True LMM in 7 dogs was 96 +/- 6 g (SE). Method A yielded 122 +/- 9 g (P less than 0.01) and method C 91 +/- 6 G (P greater than 0.05). Linear regression analysis between calculated and weighed LMM yielded a correlation coefficient of 0.936 in A, 0.938 in B and 0.931 in C. The SEE was 8.8 g, 7.5 g and 6.6 g, respectively. It is concluded that LMM can be determined with reasonable accuracy from linear regression equations whereby method C appears to be the preferable mode of calculation (smallest SEE).

Angiocardiography↗
PubMed1975

Light- and electron microscopic investigations of pulmonary tissue after high-frequency positive-pressure ventilation (HFPPV).

Narcotisized dogs were artificially ventilated for periods of two to five hours with HFPPV. During this time the blood gases, pH and bases were controlled. In spite of sufficient oxygenation and CO2-elimination, a metabolic acidosis developed which could not be fully compensated by the addition of buffer solutions. In light and electron microscopy these lungs did not differ significantly from control lungs. Haemorrhages or atelectases were never observed. Type I cells as well as Type II cells in the alveoli are unchanged, i.e. the Type II cells were not depleted but contained numerous typical lamellar bodies with a diameter of 0.4-1 mu. The blood gas barrier was not widened and was ca. 3000 A wide. The alveolar surface was coated by an often fragmented electron-dense film (monolayer of the surfactant).

Acid-Base Equilibrium↗