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Biomedical subjects

W Rudolph

Publications and source records attributed to W Rudolph.

At least 55 records · Page 3Linked to original sources
PubMed1988

Restenosis after balloon dilatation of coronary stenosis, multivariate analysis of potential risk factors.

This study was undertaken to analyze change in stenosis caliber up to six months after PTCA with respect to regression or progression as well as to detect factors which possibly influencing the restenosis rate. A computer assisted system with high accuracy was used for two-dimensional quantitation of stenosis. A linear multivariate analysis was applied to quantitative and qualitative angiographic data as well as to clinical findings obtained before, immediately after and six months post-PTCA in 95 consecutive patients in whom 101 stenoses were dilatated. All patients were on a standard medical regimen of aspirin or coumadin and nifedipine. After six months, 56 patients showed a change in minimal stenosis area (mSA) of less than 1 mm2 (no progression), 33 patients showed a decrease in mSA of greater than 1 mm2 which rendered the stenosis with greater than 70% luminal reduction, and 12 patients showed a decrease in mSA of greater than 1 mm2 which did not, however, result in high-grade luminal narrowing. With regard to factors capable of affecting restenosis rate, there was no relationship between extent of dilatation achieved, local dissection, stenosis configuration or localization, calcification, patient age, sex, duration of symptoms, overweight, cholesterol, triglycerides, HDL, LDL, smoking, hypertension or diabetes. However, a relationship was found between the discontinuation of aspirin or coumadin as a result of GI side effects or bleeding (2% no progression; 20% progression). Thus, antiplatelet therapy appears to be important with respect to long-term results after PTCA.

Angina Pectoris↗
PubMed1988

[Color Doppler sonography (angiodynography) in the assessment of the arterial vascular bed of the lower extremities].

With color Doppler ultrasonography, since its inception two years ago, through combination of color-coded flow and gray-coded vessel and tissue imaging, a new technique is available with which, based on the information derived from the Doppler principle, characterization is enabled of the direction of blood flow coded in red or blue, the velocity in varying color intensities and turbulent flow through color mixing. For determination of the velocity of flow at any point in the vessel, additionally, the pulsed Doppler method is available. The diagnosis of obstruction is based on delineation of plaques in the vascular lumen as well as changes in profile of the flowing blood. Color Doppler ultrasonography enables differentiation of high-grade stenosis from occlusion, aids and rapid localization of a stenosis and permits correction of the angle between the Doppler beam and flow in the vessel without providing quantitative evaluation of the degree of stenosis; the latter, however, can be mediated from the recorded velocity profile of the pulsed Doppler method Through demonstration of color-coded blood flow, the patency of bypass grafts can be documented. Additionally, information can be obtained with regard to the proximal and distal anastomoses, flow patterns in the region of preserve venous valves, stenoses and arterio-venous fistulas. Pseudoaneurysms are seen as cavity-like perivascular structures devoid of echo signals, the contiguous access to the lumen of which can be verified by display of pulsatile, systolic-diastolic flow in the color-coded image. With color Doppler ultrasonography abnormal flow patterns incurred through atherosclerotic changes in the vessel wall, stenoses, anastomoses, aneurysms and pseudoaneurysms can be reliably detected.(ABSTRACT TRUNCATED AT 250 WORDS)

Arterial Occlusive Diseases↗
PubMed1988

[Doppler echocardiographic findings before and after balloon catheter valvuloplasty in mitral stenosis].

This study was undertaken to analyze the diagnostic value of Doppler echocardiographic determination of pressure gradient and valve orifice area for the evaluation of balloon valvuloplasty in mitral stenosis as well as the echocardiographic assessment of calcification, leaflet motion and the subvalvular apparatus for characterization of the most favorable morphologic prerequisites for this procedure. Doppler echocardiographic studies were performed in 24 patients with mitral stenosis, 21 women and three men, age range from 29 to 79 years, mean age 55 years, one day before and after balloon valvuloplasty and the results were compared with invasively-determined hemodynamic measurements. The Doppler echocardiographic determination of the mean pressure gradient before and after balloon valvuloplasty was carried out with the modified Bernoulli equation from the velocity profile of the stenotic jet and calculation of the mitral valve orifice area using the pressure half-time method. Echocardiographic assessment of valve morphology and motion was based on two-dimensional echocardiographic cross-sectional images. Calcification, as observed in the parasternal cross-sectional image, was classified as absent (grade 0), slight to moderate (grade 1) or severe (grade 2). Motion of the valve leaflets, as judged from the apical four- and two-chamber views, was assigned one of five grades taking into consideration the motion of the bodies of both leaflets from the systolic baseline position as less than 10 degrees, between 10 and 45 degrees and more than 45 degrees. The subvalvular apparatus, that is the chordae and the papillary muscles, were graded as unremarkable (grade 0), slightly altered (grade 1) and markedly altered (grade 2). Using a score derived by adding the grade of these three criteria, a formal value between 0 and 8 was calculated. Hemodynamic measurements were carried out with standard techniques employing simultaneous registrations of left atrial and left ventricular pressure for evaluation of the mean diastolic pressure gradient. Determination of the stroke volume was based on biplane left ventriculograms using Simpson's rule. The valve orifice area was calculated according to the Gorlin formula. Dilatation was carried out with a Bifoil (12F, balloon diameter 2 X 19 mm) or Trefoil (10F, 3 X 12 mm) valvuloplasty catheter. After PTVP, on comparison of the Doppler-echocardiographically determined pressure gradient (5.7 +/- 1.9 mm Hg) with that determined invasively (6.4 +/- 3.2 mm Hg) there was a moderate correlation (n = 19, r = 0.74, SEE = 1.3 mm Hg) where the noninvasively-determined values, in general, were smaller.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1988

[Doppler echocardiography in the evaluation of the results of balloon catheter valvuloplasty in aortic valve stenosis].

This study was undertaken to assess the diagnostic value of Doppler echocardiographic methods for determination of the mean pressure gradient and valve orifice area in the evaluation of the results of balloon valvuloplasty (PTVP) in aortic stenosis by comparison with invasively-determined measurements. In 16 patients with aortic valve stenosis, eight men and eight women, mean age 64 +/- 10 years, Doppler echocardiographic studies were performed one day before and after PTVP. The mean pressure gradient was calculated with the aid of the modified Bernoulli equation and the aortic valve orifice area with the continuity equation. After PTVP, on comparison of Doppler echocardiographic and invasively-determined pressure gradients, there was no significant correlation (n = 16, y = 0.3x + 18.7, r = 0.36, SEE = 9.3 mm Hg) (Figure 2). Prior to PTVP the two methods correlated reasonably well with each other (n = 16, y = 0.6x + 7.7, r = 0.54, SEE = 17.8 mm Hg) (Figure 2). On comparison of the Doppler echocardiographic and invasively-determined aortic valve orifice area, both after and before PTVP, there were significant linear correlations (n = 8, y = 0.41x + 0.41, r = 0.73, SEE = 0.12 cm2 and n = 14, y = 0.71x + 0.17, r = 0.86, SEE = 0.10 cm2, respectively) (Figure 4). Correspondingly, there was close agreement between the change in absolute aortic valve orifice areas determined invasively (0.18 +/- 0.15 cm2) and noninvasively (0.15 +/- 0.10 cm2, n = 8).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1988

[Balloon valvuloplasty in mitral stenosis. Hemodynamic results, influencing factors and comparison with surgical procedures].

Percutaneous transluminal valvuloplasty for mitral stenosis represents an alternative to surgical treatment. The reported increases in valve orifice area vary with values from 0.6 to 2.03 cm2 over a wide range. This study was undertaken to evaluate our own results and to determine if factors could be identified which may exert an influence on the outcome of the procedure. Additionally, to evaluate this new method of treatment, the pressure-flow relationship at rest and during exercise after valvuloplasty was compared with that observed after mitral valve commissurotomy or mitral valve replacement. In 25 patients with moderately-severe to severe mitral stenosis, mean age 56 +/- 11 years, mean valve orifice area 1.1 +/- 0.37 cm2, 52% with preexistent regurgitation, antegrade percutaneous, transvalvular valvuloplasty was carried out. Diagnostic catheterization was performed immediately prior to and after the procedure. Two concurrent groups of patients were analyzed for the purpose of comparison: 26 consecutive patients who underwent mitral valve commissurotomy with a comparable valve orifice area of 1.13 +/- 0.39 cm2 of whom 31% had a regurgitant component; and 37 consecutive patients who had valve replacement mostly with a Björk-Shiley prosthesis (M 29, 31, 33), mean age 52 +/- 8 years, comparable valve orifice area of 1.1 +/- 0.37 cm2 and a regurgitant component in 65%. Dilatation of the valve was carried out after transseptal catheterization with the use of an 8F Mullins sheath introducing a 7F balloon-tipped catheter (Critikon) via the left atrium, the left ventricle and into the descending aorta through which a 300 cm long 0.035" guidewire was advanced. By means of a retrieval catheter introduced via the femoral artery into the descending aorta, the guidewire was exteriorated via the femoral artery. After dilatation of the septum with a 9F dilatation catheter with a balloon of 8 mm diameter, a 10F or 12F dilatation catheter (Trefoil 3 X 12 mm or Bifoil 2 X 19 mm) (Schneider-Shiley) was advanced transseptally and the balloons positioned at the level of the mitral valve. The balloons were inflated with a pressure averaging 3.6 + 0.65 atmospheres (2-4.7 atm) and a mean duration of 27 +/- 8 s (16 to 45 s) on the average 3.9 +/- 1.6 times (1 to 9X) until disappearance or widening of the hour-glass waist of the balloon.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1987

[Interval therapy in effective treatment of angina pectoris using nitroglycerin patch systems. A controlled study with determination of nitroglycerin plasma levels].

In ten patients with angiographically-documented coronary artery disease, stable angina pectoris and reproducible exercise-induced ST-segment depression, the extent and duration of antiischemic and antianginal effects of transdermal nitroglycerin patches delivering 10 mg/24 hours were investigated according to a double-blind, crossover, placebo-controlled protocol. Exercise testing and blood sampling for determination of nitroglycerin plasma concentrations were carried out at 2.5 and twelve hours after initial application, at 2.5, twelve and 24 hours after renewed application subsequent to a twelve-hour treatment pause as well as at 2.5 hours after application of a third patch (Figure 1). At 2.5 hours after initial application there was a reduction in exercise-induced ST-segment depression from 2.7 mm +/- 0.19 (SEM) to 0.75 +/- 0.2 (-72%; p less than 0.001) (Figure 2). The exercise capacity to onset of 1 mm ST-segment depression increased from 117 Watt X min +/- 34 (SEM) to 361 Watt X min +/- 84 (+210%; p less than 0.001) (Figure 3). At twelve hours, exercise-induced ST-segment depression was reduced only from 2.5 mm +/- 13 to 1.77 +/- 0.2 (-32%; p less than 0.01) and the increase in exercise capacity to onset of 1 mm ST-segment depression was narrowed from 136 Watt X min +/- 28.5 to 215 Watt X min +/- 43 (+59%; p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Cutaneous↗
PubMed1987

[Discontinuous drug release as an alternative to interval therapy in the treatment of coronary heart disease with nitroglycerin patches].

In ten patients with angiographically-documented coronary artery disease, according to a double-blind, placebo-controlled protocol, the antiischemic and antianginal actions of a new transdermal nitroglycerin patch system with discontinuous drug release (7.5 mg/24 hours, two-thirds of which is released within the first twelve hours) were assessed on three consecutive days to determine whether effective longterm treatment is possible (Figure 1). At 2.5 hours after initial application, as compared with placebo, the active drug led to a reduction in exercise-induced ST-segment depression of 55.9% (p less than 0.001; Figure 2), the exercise capacity to onset of 1 mm ST-segment depression increased 129% (p less than 0.05; Figure 3), angina pectoris during exercise was incurred in only 20% of the patients (Figure 4). At twelve hours, the corresponding effects were attenuated at -44%, +114% and +60%. 24 hours after patch application, an appreciable effect could no longer be detected. After renewed patch application on the second day, as compared with the initial application, the actions on ST-segment depression and exercise capacity were diminished about 20%. Similarly, there was an increase in the number of patients who developed angina during exercise. At twelve hours, there was more marked attenuation of the effects on all three parameters than that which had already been observed on the first day. At 24 hours, there were no significant effects. At 2.5 hours after renewed patch application on the third day, the effects on ST-segment depression, exercise capacity and incurrence of angina pectoris were essentially similar those seen after the second application.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Cutaneous↗
PubMed1987

[Grading of the aortic valve regurgitation with the color Doppler echocardiography].

This study was undertaken to assess whether various parameters of the extension of aortic regurgitation with color Doppler imaging are comparable with angiographic techniques for classification of severity. In 39 patients with aortic regurgitation, 14 women and 25 men, mean age 53 +/- 14 years, Doppler echocardiographic examinations were performed prospectively for determination of length, width and area of the maximal extension of regurgitant flow (Figure 1). Angiographic assessment of severity showed grade I regurgitation in nine, grade II in 14, grade III in twelve, and grade IV in four patients. The length of regurgitant flow in the color Doppler image showed an increasing tendency with increasing angiographic severity (r = 0.38, SEE = 13 mm), however, for various grades of severity, there was clear overlap. The area of regurgitation, similarly, due to substantial overlap, correlated only weakly with the angiographic data (r = 0.54, SEE = 196 mm2). To date, there is not theoretical basis for a correlation of the length and area of regurgitant flow with the severity and experimental studies have shown that there is no simple relationship. The best correlation was found for the width of the regurgitant flow (r = 0.63, SEE = 3 mm), however, here as well, there was clear overlap of data such that there was no statistically significant difference between grades II and III. Unequivocal differentiation of the values could only be achieved between grades I and IV. Based on a width of 7 mm, high-grade regurgitation could be detected with a sensitivity of 75% and a specificity of 74%.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1986

[On the topic: Doppler echocardiography].

With Doppler echocardiography, in addition to delineation of cardiac structures and their motion, intracardiac pressure and blood flow characteristics can also be assessed. The theoretical basis for this diagnostic method had been formulated by Christian Doppler approximately 100 years prior to its initial use for measuring blood flow in the heart with the aid of ultrasonic waves. The development of continuous-wave Doppler which subsequently yielded the capability for determination of the direction of blood flow, was followed by the development of pulsed Doppler for measurement of blood flow velocity in localized regions of the heart. Inter-currently, combinations of pulsed Doppler together with echocardiography as well as that of pulsed and continuous-wave Doppler were successfully incorporated into a single unit. The most recent development is represented by the realization of color Doppler systems. The possible applications of Doppler echocardiography in cardiology are manifold. Stroke volume and cardiac output determinations are based on measurement of the velocity profile in a specified region of the heart or neighboring great vessels and calculation of the respective area of flow. Intracardiac pressures can be determined in the presence of valvular stenosis, regurgitation or shunt using the pressure differences between contiguous cardiac or vascular structures as calculated by the modified Bernoulli equation and the clinically-measurable or estimable pressure in one of the respective areas. Further methods encompass parameters which can be obtained with the aid of the velocity profile of the pulmonary flow. While two-dimensional echocardiography remains the standard for assessment of systolic left ventricular function, evaluation of diastolic function can be achieved with Doppler echocardiography based on parameters of mitral inflow.(ABSTRACT TRUNCATED AT 250 WORDS)

Color↗
PubMed1986

[Avoidance of tolerance development to long term therapy with nitrates through correct dosage].

Tolerance development to organic nitrates, with respect to blood pressure reduction and precipitation of headache, had been assumed for almost a century but it was not until 1980 that the anti-ischemic effect was proven to be subject to this phenomenon, in a placebo-controlled, double-blind study carried out by our group exemplarily employing long-term treatment with isosorbide dinitrate (ISDN) in sustained-release form. Subsequent studies showed that tolerance development was also incurred during administration of ISDN, nonsustained-release form, 40 mg q.i.d. and on application of transdermal nitroglycerin patch systems. Both changes in the pharmacokinetics and activation of counter-regulatory mechanisms can be excluded as meaningful etiologic factors for the development of nitrate tolerance. It must be assumed that intracellular changes in the target organ which are associated with a diminished responsiveness for guanylate cyclase activation are at the basis of tolerance development. Prerequisite, according to laboratory experiments and clinical observations, are high concentrations of nitrates. After development of tolerance, on allowing a nitrate-free interval to intervene, the attenuated effects rapidly resume. Consequently, we investigated the hypothesis that tolerance could be avoided by an intermittent administration of nitrates which prevented accumulation of high serum concentrations. This was confirmed in two placebo-controlled, double-blind studies. Both during treatment with 20 mg ISDN in the morning and at midday as well as with the once-daily administration of 120 mg ISDN sustained-release form in the morning, there was an unequivocal anti-ischemic effect without tolerance development together with a significant reduction in the rate of anginal attacks and nitrate consumption.(ABSTRACT TRUNCATED AT 250 WORDS)

Angina Pectoris↗
PubMed1986

[Long-term follow-up of aortic or mitral valve replacement. Comparison of results following implantation of a mechanical or biological artificial valve].

The prognosis of valvular heart disease is favorably influenced by surgical treatment in spite of the possible incurrence of early or late postoperative complications. The hemodynamic properties of currently implanted bioprostheses and mechanical prostheses are essentially similar. It can be assumed that the fate of the patient, after having survived the early-postoperative phase, is predominantly dependent on the underlying disease and on complications of the prosthetic valve, itself, or the inherent necessity for chronic anticoagulation. To characterize the longterm course more closely, in this study in patients with prosthetic aortic or mitral valves, analysis of the survival rate as well as incidence of valvular dysfunction, late endocarditis, thromboembolism and bleeding associated with anticoagulant therapy was performed separately for patients with Björk-Shiley prostheses and for those with bioprostheses. The study encompasses 407 patients after isolated aortic valve replacement, 226 with Björk-Shiley prosthesis and 181 with bioprosthesis, as well as 269 patients after isolated mitral valve replacement, 142 with Björk-Shiley prosthesis and 127 with bioprosthesis (Table 2). All patients had valve replacement between 1975 and 1983 which was performed in the Department of Cardiovascular Surgery at the German Heart Center in Munich under comparable conditions, since 1977 with employment of cardioplegia. The preoperative characteristics of the groups compared did not differ significantly from each other (Table 1). Continuous follow-up was obtained in 95% of the patients. The mean observation period of all four compared patient groups ranged between 52.1 and 61.3 months. The term "major complication" was used to designate late-postoperative death, hemodynamic derangement due to prosthetic dysfunction, late endocarditis as well as major thromboembolism or bleeding. Prosthetic dysfunction in the case of Björk-Shiley valves was designated as mechanical or due to thrombosis, in the case of bioprostheses as valve degeneration or thrombosis. Late endocarditis was diagnosed only on documentation of - with a minimum interval of 30 days between valve implantation and onset of symptoms - changes in auscultatory findings and a morphological substrate on the implanted valve. Thromboembolism was assumed, after ruling out bleeding, only if a definitive or highly-probable transient or permanent neurologic deficit or a well-established suspicion of acute ischemia in an extremity or visceral organ was present. A bleeding complication was considered as such only if treatment by a physician was required.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗