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Biomedical subjects

U Nellessen

Publications and source records attributed to U Nellessen.

49 records · Page 3Linked to original sources
PubMed1988

[Comparison of high and low osmolar roentgen contrast media in quantitative coronary angiography].

In 48 patients undergoing diagnostic coronary angiography changes of mean diameters of angiographically "normal" coronary segments after intracoronary injections of diatrizoate 76% or iopromide 370 performed in different intervals, were analyzed with a computer-assisted contour detection system (CAAS). Four study protocols were applied, differing in respect to the type of contrast medium administered and/or to the timing of the reference- and control-angiograms in the course of diagnostic coronary angiography. Coronary angiograms in identical projections were performed before (= reference) and directly after (1. control = C1) diagnostic angiography of the left coronary artery by injection of either diatrizoate 76% (group 1, 10 patients) or iopromide 370 (group II, 11 patients). Additional coronary angiograms were performed 1, 3, 6, and 10 min after C1. During diagnostic angiography in either group about eight dye injections were performed in about seven min. With diatrizoate 76% a significant coronary dilation averaging 18.9 +/- 6.7% (p less than 0.001) was observed at C1, depending on the number of diagnostic dye injections performed per min (mean 1.2 +/- 0.3) and on the interval between the last diagnostic injection and C1 (mean 73 +/- 35 s). Coronary dilation persisted up to the sixth minute (6.2 +/- 4.6%, p less than 0.01). With iopromide 370 a small but significant coronary dilation was observed merely at C1 (5.8 +/- 4.3%, p less than 0.05). In two other studies coronary angiograms were performed in identical projections immediately following complete diagnostic coronary angiography (reference) and in addition after 3, 4, 5, 6, 10, and 20 min (group III, 18 patients) and after 10, 20, and 30 min, respectively (group IV, 9 patients) by administration of diatrizoate 76% as the only contrast medium. Short injection intervals (1 min) resulted in a mild coronary dilation (mean up to 2.4 +/- 4.1% compared to reference; p less than 0.05), longer intervals (3-10 min) resulted in a marked diameter reduction (averaging up to -9.7 +/- 9%; p less than 0.05), probably a consequence of the return of coronary vasomotor tone to baseline levels. These results suggest that in quantitative coronary angiographic studies (e.g., testing coronary vasomotility) non-ionic contrast media should preferably be applied, and adequate injection intervals (greater than 2 min) are mandatory. In intervention- and follow-up studies based on repeated coronary angiograms dye-induced changes of coronary vasomotor tone can be avoided by premedication with vasodilating drugs, e.g. nitrates, and/or calcium antagonists.

Adult↗
PubMed1987

International nifedipine trial on antiatherosclerotic therapy (INTACT).

A number of animal studies revealed an inhibition or retardation of the progression of atherosclerosis by calcium-antagonists. Encouraged by these studies, a multicenter trial on the progression of coronary artery disease (CAD) in man was initiated testing the antisclerotic effect of nifedipine against placebo in 426 patients with mild to moderate coronary disease over 3 years. All patients underwent coronary angiography before entering the trial and will be restudied after 3 years; changes of the coronary artery lumen size are quantitatively assessed by a computer-assisted system (CAAS). INTACT (International Trial on Antiatherosclerotic Coronary Therapy) is therefore the first randomized prospective study on the progression of CAD based on a quantitated anigraphic control of the coronary system. This report presents the design of this still-ongoing study as well as inclusion and exclusion criteria. The quantitative evaluation of the coronary angiograms and the mode of compliance test are described in detail. A number of baseline data as well as the preliminary results of the quantitative evaluation of the first coronary angiograms are presented. Beside the results on the effect of the calcium-antagonist nifedipine on the progression of CAD, INTACT might also supply information on the antiatherosclerotic potency of other drugs administered additionally (beta-blockers and nitrates) and of HDL-cholesterol.

Adult↗
PubMed1987

[Change in the diameter of the coronary vessels following sublingual or intravenous nifedipine administration correlated with the plasma level].

UNLABELLED: The diameter changes of angiographically normal epicardial coronary arteries were studied in 25 patients in correlation to nifedipine plasma levels. In group 1 (15 patients) 20 mg of s.l. nifedipine were administered. Measurements of the coronary lumen size (automated contour detection system, accuracy 0.12 mm) and detection of plasma levels (gas-chromatography) were done before and 10, 20 and 30 min after drug administration. According to the slope of nifedipine plasma levels, patients were divided into group 1 A (n = 4) and 1 B (n = 11). Plasma levels in both groups were: at 10 min, 27.8 +/- 9.8 and 13.5 +/- 4.5 ng/ml resp.; P less than 0.05; at 20 min, 54.0 +/- 11.7 and 21.7 +/- 6.6 ng/ml resp.; P less than 0.001; at 30 min, 79.1 +/- 9.3 and 28 +/- 9.8 ng/ml resp.; P less than 0.001. The corresponding diameter changes in A and B were: 7.3 +/- 5.1%/.-5.6 +/- 9.0% resp.; P less than 0.01; 11.4 +/- 4.1% and -4.5 +/- 11.3% resp.; P less than 0.01; 14.5 +/- 5.9% and 0.5 +/- 13.6% resp.; P less than 0.05. In group 2 (10 patients) 1 mg nifedipine was administered intravenously within 4 min. Measurements were done at 1 min intervals during infusion as well as 7 and 15 min after beginning and compared to a placebo group (n = 10). Peak plasma levels amounted to 16.7 +/- 5.7 ng/ml after 7 min. The maximum coronary dilation was reached after 4 min (verum 5.0 +/- 6.8%; placebo 3.2 +/- 3.6%). Significant differences between both groups were observed after 7 min (verum 4.1 +/- 5.3%; placebo -3.1 +/- 5.8%, P less than 0.05) and 15 min (verum 1.2 +/- 3.2%; placebo -6.2 +/- 8.4%; P less than 0.05). CONCLUSION: based on significantly different plasma levels following sublingual application of 20 mg nifedipine a classification of patients into "early-" and "late-coronary-responders" could be established. After intravenous infusion of 1 mg nifedipine peak plasma levels were much lower than after sublingual application of 20 mg and coronary diameters showed only a mild increase.

Administration, Oral↗
PubMed1986

[Unstable angina pectoris: disease picture and study of its course].

The object of the present study is to analyse the history of patients with typical unstable angina. For this purpose the data of all patients admitted to the Hannover Medical School between 1977 and 1983 and taken to the CCU because of proven unstable angina (history, duration of symptoms, intrahospital mortality, incidence of infarction, medical or surgical therapy, coronary pathomorphology, mortality after release from hospital, late incidence of infarction and rehospitalization) were documented and stored on a data bank for statistical analysis. 123 patients were entered into the study (97 males, 26 females; average age 58.4 +/- 9.2 years); during hospitalization all patients had angina at rest, 94% had transient ECG-changes (ST-segment changes, BBB etc.). The average follow-up was 4.2 +/- 2.0 years. 80 patients of the whole study population were treated medically, 43 underwent early bypass surgery. The two groups were different with respect to coronary pathomorphology (number of diseased vessels) as well as left ventricular wall motion, which was significantly more impaired in the surgical group (p less than 0.05). The hospital-mortality in the surgical group amounted to 9.3% (n = 4), the incidence of infarction to 18.6% (n = 8); the hospital mortality in medically treated patients was 2.5% (n = 2), the incidence of infarction 7.5% (n = 6). During the whole study period (average follow-up 4.2 years) the overall mortality amounted to 21%, the infarction rate was 23.5%: The cumulative survival rates revealed no significant difference between the 2 groups: after 3 years 84% of all patients were still alive, 65% without new infarction during the observation period; the rate of rehospitalization amounted to 50%. At the end of the study class III or IV angina (NYHA-criteria) was much more common in the medically treated than in the surgically treated group (NYHA mean 2.5 versus 2.0; p less than 0.5). The relatively high rate of perioperative death and myocardial infarction in the surgical group is based on the selection of patients according to coronary pathomorphology and the clinical status.

Angina Pectoris↗
PubMed1986

[Importance of transesophageal echocardiography in the diagnosis of cardiac and paracardiac space-occupying processes].

The diagnostic value of transoesophageal echocardiography in the detection of cardiac and extracardiac masses has not yet been properly established. We therefore studied 23 patients (7 males, 16 females, mean age 54.7 years) using transoesophageal echocardiography in addition to conventional transthoracic echocardiography. Nine patients had an atrial thrombus, 6 an atrial myxoma and 8 extracardiac masses. The studies were performed without complications. Transthoracic as well as transoesophageal echocardiographic detection of atrial thrombus or myxoma (n = 15) was successful in all patients except 1 with a thrombus in the left atrial appendix, which could only be visualized by transoesophageal echocardiography. In contrast, accurate diagnosis of extracardiac masses could be established only by transoesophageal echocardiography in 5 of 8 patients (62.5%). In all 23 patients the judgement of the mobility of the tumor, as well as its acoustic properties and wall adherence was markedly facilitated by transoesophageal echocardiography. Thus, this method is a useful diagnostic tool for detection of extracardiac masses, whereas in patients with atrial thrombus or myxoma it can give important additional information.

Adult↗
PubMed1985

Impending paradoxical embolism from atrial thrombus: correct diagnosis by transesophageal echocardiography and prevention by surgery.

During recovery from a posterolateral myocardial infarction, a 56 year old patient developed signs of deep vein thrombophlebitis and subsequently of pulmonary embolism. After conventional echocardiography showed masses in both atria, transesophageal two-dimensional echocardiography clearly revealed an elongated mass overriding an atrial septal defect. Impending paradoxical embolism was confirmed at surgery.

Echocardiography↗
PubMed1985

Chronic aortic regurgitation: reassessment of the prognostic value of preoperative left ventricular end-systolic dimension and fractional shortening.

The prognostic significance of a preoperative echocardiographic left ventricular end-systolic dimension (ESD) greater than 55 mm and/or fractional shortening (FS) of 25% or less was evaluated retrospectively in 84 patients who had undergone aortic valve replacement for isolated chronic aortic regurgitation due to various causes. Postoperative survival, improvement in symptoms, and echocardiographic evidence of regression of left ventricular dilatation and hypertrophy were compared between patients with a preoperative ESD greater than 55 mm (category 1) and those with an ESD of 55 mm or less (category 2) and between patients with FS of 25% or less (category 3) and those with FS greater than 25% (category 4). Patients in categories 1 and 3 had a higher preoperative left ventricular end-diastolic dimension (EDD) and cross-sectional area than those in categories 2 and 4, respectively, but their preoperative functional impairment (NYHA class) was similar. There were 13 deaths, only two of which (one early, one late) could be attributed to left ventricular dysfunction. In both, FS was 25% or less and in one ESD was greater than 55 mm. There was a weak association without useful positive predictive value between the echocardiographic variables and postoperative death due to all causes. Among 42 patients with a preoperative ESD greater than 55 mm and/or FS of 25% or less, 33 (79%) were alive at a mean follow-up of 29.5 months. Symptoms improved in all categories of survivors, with the postoperative NYHA class being similar between categories 1 and 2 and between categories 3 and 4. Among 48 survivors with high-quality echocardiograms both before and after surgery, EDD fell in all groups but fell to a lesser extent in category 3 than in category 4. Postoperative cross-sectional area fell to the same level in all categories. Follow-up intervals were similar in all categories. We conclude that in patients undergoing aortic valve replacement for chronic aortic regurgitation, a preoperative ESD greater than 55 mm or an FS of 25% or less does not reliably predict early or late death, does not correlate with lack of improvement in symptoms, and does not preclude postoperative regression of left ventricular dilatation and hypertrophy. Thus these echocardiographic criteria alone cannot be used for the timing of surgical intervention in these patients.

Adolescent↗
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↗
PubMedDate not supplied

Flow velocity acceleration in the left ventricle: a useful Doppler echocardiographic sign of hemodynamically significant mitral regurgitation.

Doppler echocardiography is a sensitive method to detect mitral regurgitation in patients with both native and prosthetic valves. However, estimates of the amount of mitral regurgitation remain semiquantitative, and even severe mitral regurgitation may be underestimated in the presence of markedly eccentric regurgitant jets or acoustic shadowing of the left atrium by mitral or aortic prostheses. This report describes the Doppler findings in 10 patients with severe native valve mitral regurgitation (angiographic grade III or IV) and in 15 patients with severe bioprosthetic mitral regurgitation that required valve replacement. An increase in peak mitral flow velocity above normal values was seen in eight of 10 patients with severe native valve mitral regurgitation (greater than or equal to 130 cm per second) and 11 of 15 patients with severe prosthetic valve mitral regurgitation (greater than or equal to 210 cm per second). One of 10 patients with a native valve and four of 15 patients with a bioprosthetic valve appeared to have only a localized left atrial systolic flow disturbance, incorrectly suggesting that the mitral regurgitation was mild. However, in all patients with severe mitral regurgitation, a low velocity (less than 100 cm per second) flow signal could be recorded in the left ventricle that was directed toward the mitral valve in systole. This flow signal showed a gradual increase in velocity as the sample volume was moved toward the mitral valve, with an abrupt further increase on entry into the left atrium. This signal was continuous with antegrade mitral flow and had the same orientation as mitral regurgitation recorded by continuous wave technique from the apex. A similar flow signal was not recorded in the left ventricle of any individual in a control group of 30 patients who had no mitral regurgitation or who had angiographic grade I or II mitral regurgitation. These findings suggest that acceleration of left ventricle flow toward the mitral valve in systole is only recorded when there is hemodynamically significant mitral regurgitation that is approximately equal to angiographic grade III or IV. Recognition of this Doppler finding may help in the estimation of mitral regurgitation severity, especially in difficult diagnostic situations.

Aged↗
PubMedDate not supplied

Improvement in left ventricular diastolic filling by septal myectomy in hypertrophic cardiomyopathy.

Abnormalities in left ventricular diastolic function or filling are considered to be responsible for some of the symptoms in patients with hypertrophic cardiomyopathy. To clarify whether the abnormalities in left ventricular diastolic filling are improved by septal myectomy, 13 patients with hypertrophic cardiomyopathy and intracavitary pressure gradient were studied preoperatively and postoperatively by use of pulsed Doppler echocardiography. Peak early diastolic filling velocity (E), the ratio of peak early diastolic filling to peak atrial filling velocities (E/A ratio), and deceleration time were measured from the transmitral flow velocity pattern before and after septal myectomy. Although E and E/A ratio did not change after septal myectomy, deceleration time significantly shortened from 314 +/- 72 to 271 +/- 53 milliseconds (n = 10; p less than 0.05). Further, if seven patients with significant changes in heart rate (greater than 30%) or in the Doppler-determined severity of mitral regurgitation (more than one degree) were excluded (because these parameters may effect E and E/A ratio), there were also significant changes in E (81 +/- 21 versus 98 +/- 25 cm/sec, p less than 0.05) and in E/A ratio (0.84 +/- 0.17 versus 1.14 +/- 0.33, p less than 0.05). Because left ventricular systolic function has been demonstrated to remain constant or to decrease by most measures after septal myectomy, relief of some symptoms may be largely the result of the improvement in diastolic filling suggested by these criteria.

Adult↗
PubMedDate not supplied

Doppler ultrasound of the subclavian artery as an aid to quantification of aortic insufficiency.

Aortic insufficiency (AI) induces backflow of blood in the arterial system that is most pronounced in the major arteries close to the heart. Assuming that the intensity of the arterial backflow of blood may reflect the severity of AI, the systolic and diastolic flow profiles of the subclavian artery were studied in 40 patients with and 10 patients without AI that was angiographically proved by use of continuous wave Doppler ultrasound (8 MHz transducer, supraclavicular approach). Patients with angiographically determined severe AI (n = 17) had significantly higher diastolic regurgitant flow velocities (V-max) than patients with only mild (n = 9) or moderate (n = 14) degrees of AI (Severe AI = 35.0 +/- 12.0 cm/sec, moderate AI = 16.8 +/- 3.9 cm/sec, mild AI = 7.4 +/- 2.6 cm/sec; p < 0.01) and also showed significantly higher values with regard to the time velocity integral of the regurgitant jet (severe AI = 13.8 +/- 5.6 cm; moderate AI = 5.7 +/- 2.4 cm, mild AI = 1.4 +/- 0.9 cm; p < 0.01). After classification by jacknife discrimination analysis, the Doppler ultrasound grading was compared with a corresponding three-point scale (mild, moderate, severe) from aortic root angiography. A correct estimation of the severity of AI was possible in 44 of 50 patients (88%; overestimation in one, underestimation in five) and in 41 of 50 patients (83%; overestimation in one, underestimation in eight) with regard to V-max and the time velocity integral of the regurgitant jet, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Aortic Valve Insufficiency↗