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Biomedical subjects

C Leuner

Publications and source records attributed to C Leuner.

At least 19 recordsLinked to original sources
PubMed2006

Effect of transcoronary ablation of septal hypertrophy on clinical outcome in hypertrophic obstructive cardiomyopathy associated with atrial fibrillation.

BACKGROUND: Relatively few reports on the clinical impact of atrial fibrillation (AF) in hypertrophic obstructive cardiomyopathy (HOCM) are available. The aims of our study are to report the effect of transcoronary ablation of septal hypertrophy (TASH) on clinical outcome in HOCM associated with AF and to evaluate the influence of AF on symptoms and quality of life in HOCM. PATIENT AND METHODS: In 80 consecutive patients (38 f, mean age 56 +/- 17 years) with severely symptomatic HOCM referred for interventional treatment, we analyzed the prevalence of AF based on 240 Holter ECG recordings and patients' history, retrospectively. Symptoms, quality of life, number of hospital admissions and hemodynamic performance were obtained in all patients before and after TASH. Mortality was additionally investigated by letter and telephone contact. RESULTS: The overall prevalence of AF was 29%. Paroxysmal AF was detected in 17 pts (21.3%), persistent AF in 5 pts (6.3%). Only 1 pt (1.3%) suffered from permanent AF. Symptoms due to AF were present in 52.6% of the AF patients. Quality of life score was markedly improved after TASH (15.9 +/- 3.8 vs. 20.7 +/- 3.8, p < 0.001) with no difference between sinus rhythm and atrial fibrillation. However, hospital admissions were more frequent in the AF group (0.85 +/- 1.84 vs. 0.28 +/- 0.81, p = 0.03) in 32 +/- 13 months. AF patients suffered more often from syncope before TASH (30 +/- 70% vs. 10 +/- 30%, p = 0.008). Two patients with sinus rhythm at baseline died after 32 +/- 13 months from cardiovascular cause. CONCLUSIONS: Atrial fibrillation is the major cardiac arrhythmia in severe HOCM. The majority of AF patients demonstrate AF specific symptoms. The paroxysmal type of atrial fibrillation dominates by far. Both patients with and without atrial fibrillation showed similar quality of life with marked improvement after TASH.

Atrial Fibrillation↗
PubMed2006

Repithel: removing the barriers to wound healing.

BACKGROUND: Various standardized and/or validated models exist to test wound healing products. This article discusses their usefulness in clinical practice. OBJECTIVES: Major barriers to wound healing have been identified after intense interaction of research and practitioners. Although extensively tested, wound healing products are still associated with trial and error due to the high variability and complexity associated with the treatment of wounds. Therefore, the results of preclinical testing are compared and contrasted with clinical observations of a liposomal hydrogel containing 3% povidone-iodine (Repithel, PVP-ILH) to assess their expressiveness and to give the practitioner more guidance in application. METHODS: Testing of PVP-ILH included physicochemical testing according to ISO norms, testing in in vitro and in vivo models. The obtained results are compared to the clinical profile of the obtained product in randomized controlled trials and ultimately expressive case studies. RESULTS: PVP-ILH displays good local tolerance, the basis for use in sensitive and predamaged tissue. As observed in laboratory testing, it readily provides moisture and takes up limited amounts of moisture. This was also seen in the clinical testing, as the ability to keep wounds moist and incorporate a certain -- but not large -- amount of exudates. Clinical results also show clean, well-debrided wounds, an effect that (in the absence of an established model for wound cleansing) was traced to the hydrogel component carbomer. DISCUSSION: Recent consensus advocates the concept of wound bed preparation as a systematic approach to removing barriers to healing (TIME). Based on the results, tissue (removing non-viable tissue and debris) and moisture (balance) can now be better understood, and infection/inflammation (control) and edge (progressing, non-advancing or undermining wound edges) are reviewed together with previously published data to assess all aspects potentially impeding wound healing. CONCLUSION: PVP-ILH successfully removes barriers to wound healing, thus laying the foundation to high-quality wound closure. Results from many scientific disciplines can help the user to better understand a product, standardization of testing is the only way of making results comparable.

Absorption↗
PubMed2000

Transcoronary ablation of septal hypertrophy (TASH): a new treatment option for hypertrophic obstructive cardiomyopathy.

In 1991, our group started to develop a catheter interventional therapy for hypertrophic obstructive cardiomyopathy (HOCM). The new concept was proposed in 1994. It is based on the conventional PTCA technique with the aim of inducing an artificial myocardial infarction by instillation of 96% ethanol into the most proximally situated septal branch of the left anterior descending coronary artery. This leads to a subaortic contraction disorder with subsequent decrease of the intraventricular pressure gradient, shrinkage of the hypertrophied septal bulge and widening of the outflow tract ("therapeutic remodeling"). The subaortic defect is small and well demarcated as assessed by left ventricular angiography, transesophageal echocardiography and 18 F-glucose positron emission tomography. The term transcoronary ablation of septum hypertrophy (TASH) was suggested. Our patient cohort that now comprises 215 therapeutic procedures in 187 patients underwent a large variety of prospective studies (maximum follow-up 4.5 years) including invasive controls at regular intervals, investigation of hemodynamics at rest and at exercise, transesophageal and transthoracic echocardiography, Doppler echocardiography during bicycle exercise, electrophysiologic testing, Holter monitoring and measurement of myocardial metabolism and perfusion, assessment of microembolic events by transcranial Doppler sonography and histological examinations. This article gives an overview and reports our increasing experience in applying TASH. The following post-TASH findings were obtained: significant hemodynamic and clinical improvement at rest and at exercise, decrease of septum thickness, increase of outflow tract area and decrease of induced ventricular tachycardia. There were well-demarcated, histologically atypical subaortic myocardial defects, no microembolic events, abnormal early peak of infarct related enzymes, and no change of baroreflex sensitivity. Pre-/post-TASH evaluations of the patients should be based in particular on clinical symptoms correlated to the intraventricular gradient measured by bicycle exercise Doppler echocardiography and to outflow tract area as assessed by transesophageal echocardiography. Since 1994, as a roughly estimate, worldwide 1000 patients in 20 countries have been treated. According to published articles, abstract presentations and workshops, TASH consistently leads to a pronounced clinical and hemodynamic benefit for patients with HOCM. TASH has become an established technique. At least in centers with a high level of expertise, it is no longer experimental but a routinely performed alternative to surgical treatment for HOCM, i.e., the previous gold standard of therapy. Of course, patient outcome needs further careful clinical and prognostic evaluation. With respect to complications, TASH appears to be superior to surgery (transaortic septal myectomy) for HOCM. Like surgical treatment, TASH is currently indicated in critically ill patients with typical HOCM (subaortic form), who exhibit with drug refractory symptoms, including patients, who preferred DDD pacemaker therapy as a first therapeutic step but in whom this produced no subsequent clinical benefit.

Adult↗
PubMed2000

Improving drug solubility for oral delivery using solid dispersions.

The solubility behaviour of drugs remains one of the most challenging aspects in formulation development. With the advent of combinatorial chemistry and high throughput screening, the number of poorly water soluble compounds has dramatically increased. Although solid solutions have tremendous potential for improving drug solubility, 40 years of research have resulted in only a few marketed products using this approach. With the introduction of new manufacturing technologies such as hot melt extrusion, it should be possible to overcome problems in scale-up and for this reason solid solutions are enjoying a renaissance. This article begins with an overview of the historical background and definitions of the various systems including eutectic mixtures, solid dispersions and solid solutions. The remainder of the article is devoted to the production, the different carriers and the methods used for the characterization of solid dispersions.

Biological Availability↗
PubMed1997

Induction of subaortic septal ischaemia to reduce obstruction in hypertrophic obstructive cardiomyopathy. Studies to develop a new catheter-based concept of treatment.

AIM: To develop a new catheter-based method of treatment in patients with hypertrophic obstructive cardiomyopathy. METHOD: Does abolition of the blood supply to the subaortic part of the septum lead to regional myocardial ischaemia and a decrease in the left ventricular outflow tract gradient? To find this out, in 10 consecutive patients the first larger septal branch of the left anterior descending coronary artery was temporarily occluded with conventional percutaneous transluminal coronary angioplasty. The intracoronary electrocardiogram was registered for objective verification of the intended ischaemia. The intraventricular pressure was measured at rest and at the post extrasystolic beat under programmed electrostimulation of the right ventricle. RESULTS: During occlusion, regional ischaemia was observed in all patients. Simultaneously, there was a significant reduction of the intraventricular gradient from 56.2 mmHg to 32.2 mmHg (P < 0.05) followed by an increase from 32.2 mmHg to 61.1 mmHg (P < 0.01) after release of occlusion of the septal branch. During ischaemia there was no increase in left ventricular end-diastolic pressure. CONCLUSION: We conclude that the results form the basis for a new catheter interventional therapy in hypertrophic obstructive cardiomyopathy.

Adult↗
PubMed1992

Left ventricular outflow tract obstruction in patients with hypertrophic cardiomyopathy: increase in gradient after exercise.

To define alterations in the magnitude of the left ventricular outflow tract gradient during supine exercise, 10 patients with hypertrophic obstructive cardiomyopathy were studied under basal conditions and during exercise and recovery with simultaneous invasive hemodynamic measurements, particularly of the peak to peak systolic pressure gradient across the left ventricular outflow tract. Basal outflow pressure gradient ranged from 0 to 89 mm Hg (average 37.4 +/- 9.6). No increase was observed during 5 min of exercise (average 29.6 +/- 10 mm Hg, range 0 to 91; p = NS), even though arterial blood pressure, heart rate and cardiac index increased significantly in association with a decrease in peripheral vascular resistance. However, a rapid and highly significant increase in left ventricular outflow gradient occurred after exercise was completed (average 83.5 +/- 11.4 mm Hg, range 10 to 130; p less than 0.001), while arterial blood pressure, heart rate and cardiac index closely approached basal levels and total peripheral vascular resistance increased. In contrast to previous assumptions regarding the behavior of the outflow gradient in hypertrophic cardiomyopathy, obstruction to left ventricular outflow increases after rather than during supine exercise. Rapid changes in preload during recovery represent the most likely explanation for the postexercise development of outflow obstruction. New considerations regarding the mechanisms of sudden cardiac death and the therapeutic approach in patients with hypertrophic cardiomyopathy may result from this pathophysiologic observation.

Adult↗
PubMed1983

[2-dimensional echocardiography].

In the mid-seventies, echocardiographic devices for clinical use have been developed to generate real-time cross-sectional images of the heart with a rate of about 30 frames per second. This technique improved the diagnostic power of M-mode echocardiography by visualizing the chambers, valves and walls of the heart in a variety of planes. Cross-sectional echocardiography provides important information for example in the evaluation of left ventricular function, diagnosis of congenital heart diseases, endocarditis, hypertrophic cardiomyopathies, cardiac tumors and others, that cannot be determined adequately by M-mode echocardiography alone.

Cardiomyopathy, Hypertrophic↗
PubMed1981

[The diagnostic value of M-mode-, two-dimensional echocardiography, and computed tomography in comparison to the results of cardiac catheterization in the diagnosis of tumors of the heart (author's transl)].

12 patients with cardiac tumors (7 myxomas of the left, 2 of the right atrium, 2 ventricular, 2 intramural tumors and 1 epicardial cyst) were examined by M-Mode-(ME) and two-dimensional (2DE) echocardiography, computertomography (CT) and heart catheterization (HK) with angiography (A). The results were compared with intraoperative findings. There were no false negative results with 2DE and CT, but in 1 case the size of an intramural tumor was underestimated by 2DE. With ME all atrial myxomas were diagnosed, but 2 ventricular and 2 intramural tumors as well as the epicardial cyst were overlooked. Also with HK and A, the 2 intramural tumors and the epicardial cyst were not recognized well. The results indicate that the diagnosis of cardiac tumors can be made with great accuracy by noninvasive methods. The sensitivity of the single methods depends on the location of the tumors.

Adolescent↗
PubMed1979

[Arrhythmias in patients with mitral valve prolapse syndrome. An echo- and electrocardiographic study - (author's transl)].

The echocardiograms and electrocardiograms of 76 patients with mitral valve prolapse syndrome (MVP) were examined and compared with those of 20 normal subjects. 30 patients had a late systolic, 32 a holosystolic MVP, 14 patients had a mixed motion pattern of the MVP. Eighty percent of them had arrhythmias, which were detected in 44% only by 24-hours ECG, in 32% by 24-hours ECG and exercise ECG and in 4% only by exercise ECG. 16% of the patients had only atrial premature contractions (APC), 22% only ventricular premature contractions (VPC), 39% had both ventricular and atrial premature contractions. Multifocal VPC'S WERE MORE COMMON IN PATIENTS WITH LATE SYSTOLIC MVP, salvos of VPC however were detected in 3 patients with holosystolic and in one patient with late systolic MVP. Only less severe arrhythmias, in general isolated, univorm VPCs were found in 40% of the normal subjects.

Adolescent↗
PubMed1979

[The applicability of systolic time intervals in patients before and after aortic valve replacement (author's transl)].

In order to evaluate the systolic time intervals (STI) for characterizing the left ventricular pump function and the clinical course in patients with aortic valve disease, 35 patients with aortic stenosis (AS) and 25 patients with aortic insufficiency (AI class III or IV (NYHA) were studied before and 1 year after valve replacement either with Björk-Shiley, Lillehie-Kaster or Starr-Edwards aortic prostheses. Left ventricular ejection time index (LVETI), preejection period index (PEPI) and PEP/LVET were determined and compared with cardiac index (CI), stroke volume index (SVI) and ejection fraction (EF). Prosthetic valve replacement leads to a high significant decrease of LVETI from preop. 468 +/- 31 ms to postop. 394 +/- 26 ms (mean normal values 415 ms) and an increase of PEPI from 100 +/- 26 ms to 136 +/- 25 ms (normal 132 ms) as of PEP/LVET from 0.21 +/- 0.09 to 0.41 +/- 0.12 (normal 0.31). Pre- as well as postop. there is no difference in STI between AS and AI. Also the groups with the three prosthetic valve types do not differ significantly. LVETI and PEPI correlate only postop. with CI and SVI, but PEP/LVET correlates well with EF (r = -0.73) before and after operation. The comparison of STI with the hemodynamic data suggest that preop. values of STI near normal and postop. LVETI below, PEPI and PEP/LVET above the mean values of the whole group with aortic valve replacement indicate left ventricular pump dysfunction. The STI are helpful in the pre-/postop. follow-op of patients with severe aortic valve disease to characterize the clinical and hemodynamic course.

Aortic Valve↗