[Quantitative analysis of the left main coronary artery by 3D echocardiography. Role, possibilities and limitations of noninvasive imaging of the left coronary artery]. / Quantitative Analyse des Hauptstammes der linken Koronararterie durch 3D-Echokardiographie. Stellenwert, Möglichkeiten und Grenzen der nicht-invasiven Darstellung der linken Koronararterie.

The left main coronary artery was investigated in 30 patients using a transesophageal approach, and a 3D reconstruction of the 2D databases was performed. Two groups of patients were analyzed. First, patients with calcified aortic stenosis were investigated and the reconstructed data obtained were compared to the left ventricular angiogram of the left coronary artery. Second, the 2D databases of patients with non-calcified aortic valve and aortic anulus were reconstructed using the 3D technique. In group 1 the estimate in size of the left ventricular coronary artery was closely related to the diameter of the left coronary artery as obtained by the coronary angiogram (mean difference 0.08 mm, interval of confidence at 95%, -0.48 and +0.32 mm). In both groups a substantial increase in imaging of the left coronary artery was obtained compared to the standard 2D echocardiographic view (% in group 1, and % in group 2, respectively). Independent of the 3D reconstruction of the left coronary artery in the any-plane mode, an orthogonal imaging of the artery could be obtained in only 15% of patients in group 1 but in 40% of patients in group 2. We conclude that 3D reconstruction of the left coronary artery (LAD) is superior to 2D echocardiography in echo-imaging of the proximal part of the LAD and correlates strongly to the diameters measured in the left coronary angiogram. In patients with major calcification of the aortic anulus and/or a calcified native aortic valve this approach is associated with multiple artifacts in imaging. The rapid technical evolution in this technique including improvement in computer technology and appropriate software may ensure a further important role of 3D echo imaging in noninvasive visualization of the normal and diseased left main coronary artery.

Ethylnitrosourea-induced development of malignant schwannomas in the rat: two distinct loci on chromosome of 10 involved in tumor susceptibility and oncogenesis.

Inbred rodent strains with differing sensitivity to experimental tumor induction provide model systems for the detection of genes that either are responsible for cancer predisposition or modify the process of carcinogenesis. Rats of the inbred BD strains differ in their susceptibility to the induction of neural tumors by N-ethyl-N-nitrosourea (EtNU). Newborn BDIX rats that are exposed to EtNU (80 microg/g body weight; injected s.c.) develop malignant schwannomas predominantly of the trigeminal nerves with an incidence >85%, whereas BDIV rats are entirely resistant. A T:A-->A:T transversion mutation at nucleotide 2012 of the neu (erbB-2) gene on chromosome 10, presumably the initial event in EtNU-induced schwannoma development, is later followed by loss of the wild-type neu allele. Genetic crosses between BDIX and BDIV rats served: (a) to investigate the inheritance of susceptibility; (b) to obtain animals informative for the mapping of losses of heterozygosity (LOH) in tumors with polymorphic simple sequence length polymorphisms (SSLPs); and (c) to localize genes associated with schwannoma susceptibility by linkage analysis with SSLPs. Schwannoma development was strongly suppressed in F1 animals (20% incidence). All of the F1 schwannomas displayed LOH on chromosome 10, with a consensus region on the telomeric tip encompassing D10Rat3, D10Mgh16 and D10Rat2 but excluding neu. A strong bias toward losing the BDIV alleles suggests the involvement of a BDIV-specific tumor suppressor gene(s). Targeted linkage analysis with chromosome 10 SSLPs in F2 intercross and backcross animals localized schwannoma susceptibility to a region around D10Wox23, 30 cM centromeric to the tip. Ninety-four % of F1 tumors exhibited additional LOH at this region. Two distinct loci on chromosome 10 may thus be connected with susceptibility to the induction and development of schwannomas in rats exposed to EtNU.

Three-dimensional imaging of nerve tissue by x-ray phase-contrast microtomography.

We show that promising information about the three-dimensional (3D) structure of a peripheral nerve can be obtained by x-ray phase-contrast microtomography (p-microCT; Beckmann, F., U. Bonse, F. Busch, and O. Günnewig, 1997. J. Comp. Assist. Tomogr. 21:539-553). P-microCT measures electronic charge density, which for most substances is proportional to mass density in fairly good approximation. The true point-by-point variation of density is thus determined in 3D at presently 1 mg/cm3 standard error (SE). The intracranial part of the rat trigeminal nerve analyzed for the presence of early schwannoma "microtumors" displayed a detailed density structure on p-microCT density maps. The average density of brain and nerve tissue was measured to range from 0.990 to 0.994 g/cm3 and from 1.020 to 1.035 g/cm3, respectively. The brain-nerve interface was well delineated. Within the nerve tissue, a pattern of nerve fibers could be seen that followed the nerve axis and contrasted against the bulk by 7 to 10 mg/cm3 density modulation. Based on the fact that regions of tumor growth have an increased number density of cell nuclei, and hence of the higher z element phosphorus, it may become possible to detect very early neural "microtumors" through increases of average density on the order of 10 to 15 mg/cm3 by using this method.

Detection of strands in native aortic valves by transesophageal echocardiography.

Prevalence and echocardiographic characteristics of strands on the leaflets of native aortic valves were examined. According to our data, the strands we found in 39% of patients are most likely Lambl's excrescences.

[Intraventricular obstructions in dobutamine stress echocardiography: determinants of their development and clinical sequelae]. / Intraventrikuläre Obstruktionen bei der Dobutamin-Stressechokardiographie: Determinanten Ihrer Entstehung und klinische Folgen.

UNLABELLED: Dobutamine stress echocardiography (DSE) leads to strong hypercontraction, tachycardia, and peripheral vasodilatation. In previous studies systolic obstruction of the left ventricular outflow tract (LVOT) was observed as a result of these factors. To evaluate left ventricular function and morphology in patients (pts) with induced systolic LVOT obstruction, we used continuous wave (CW) doppler registrations in combination with quantitative 2-D-echocardiography in 100 pts during routinely performed DSE (5-40 micrograms/kg/min). In addition left ventricular wall thickness was measured. Symptoms were registered using a standardised questionnaire and cardiac arrhythmias were counted over a two minute interval at rest and during the maximal heart rate of each patient. During DSE dynamic flow acceleration with late systolic peak velocity above 2 m/second (s) was considered to represent LVOT obstruction in pts with normal flow profiles in the LVOT before infusion of dobutamine. For invasive studies pts were investigated with femoral catheterisation by the method of Judkins. A greater than 50% stenosis was judged to be significant. RESULTS: Examinations in 73 pts provided data of sufficient quality for echocardiographic and Doppler sonographic evaluations. 39 pts, 26 men, 13 women, mean age 64 +/- 8 years, developed late systolic flow velocities above 2 m/s and therefore formed the obstructive group (grp A). Grp B consisted of 34 pts, 26 men and 8 women, mean age 66 +/- 10 years, who showed normal time velocity integrals during DSE. In 41 pts invasive data provided information concerning the existence and severity of coronary artery disease. There were no significant differences in the increase of heart rate, the product of maximal systolic blood pressure and maximal heart rate or the percentage of pts, who reached their age corrected submaximal heart rate during DSE. Obstructive pts (group A) showed late systolic dynamic acceleration of systolic flow with a mean maximal speed of 315.4 +/- 139.8 cm/s, which peaked 0.12 +/- 0.04 s after the R-wave. From the velocities we calculated a mean pressure gradient of 47.5 +/- 39.7 mm Hg using the modified Bernoulli equation. Group B patients showed lower and earlier maximal speeds with a mean value of 158.2 +/- 37.6 cm/s, 0.09 +/- 0.04 s after the R-wave, corresponding to a pressure gradient of 10.6 +/- 4.9 mm Hg (p < 0.001). Ejection fractions were higher (p < 0.001) before the test in grp A: 68.2 +/- 8% compared to 55.7 +/- 10.4% in B. This difference increased during peak stress: 74.1 +/- 7.7% compared to 59.5 +/- 12.8%. End diastolic (EDVI) and end systolic volume indexes (ESVI) were lower in grp A (p < 0.001). During DSE, the decrease in ESVI was somewhat stronger for pts in grp A. Left ventricular hypertrophy was more often seen with obstruction. Septal thickness was increased in A: 1.45 +/- 0.34 cm compared to 1.13 +/- 0.27 cm in B (p < 0.001). Left ventricular posterior wall measured 1.03 +/- 0.28 cm in A and 0.83 +/- 0.23 cm in B (p < 0.01). 27 pts in grp B and only 9 in grp A had a history of previous myocardial infarction. Showing no difference at rest, wall motion score indexes raised under DSE in both groups and developed significantly higher scores in grp B at peak stress: 1.30 (1.0-1.90) compared to 1.18 (1.0-1.75) in A. We observed typical chest pain more often in grp B. Unspecific symptoms and arrhythmogenic complications were not statistically different, with the exception of ventricular bigeminy which was more often observed in grp B. A decline in the diastolic blood pressure was observed in pts with very severe obstruction (> 3.5 m/s, p < 0.05). Sensitivity of DSE was 84%, specificity 79%. No significant differences between pts with and without obstruction were observed. SUMMARY: Intraventricular obstructions during DSE are often observed in pts with normal systolic function at rest and during peak stress, especially in the case of left ventricular hypertrophy. (ABSTRACT TRU

Quantitative assessment of aortic stenosis by three-dimensional echocardiography.

The purpose of this study was to assess the feasibility of three-dimensional echocardiography in aortic stenosis. Planimetric determination of valve area and dynamic volume-rendered display were performed. Three-dimensional echocardiography permits display of any desired plane of the cardiac structure. Thus in the case of aortic stenosis, the plane used for planimetric evaluation can be positioned exactly through the valve orifice. Dynamic volume-rendered display may provide a spatial demonstration of the stenotic valve. In 48 patients aortic valve area was measured by planimetry. The three-dimensional data set was acquired by a workstation in the course of a multiplane transesophageal examination. Results were compared with those obtained by multiplane transesophageal two-dimensional planimetric technique and invasive measurement. A dynamic three-dimensional reconstruction was displayed. Planimetric determination of valve area was possible in 42 (88%) of 48 cases. Statistical analysis of the data acquired showed a good agreement between three-dimensional echocardiography and transesophageal echocardiography (mean difference +0.018 cm2; SD = 0.086) and between three-dimensional echocardiography and the invasive technique (mean difference +0.012 cm2; SD = 0.12). Dynamic volume-rendered display was possible in 42 of 48 cases. Three-dimensional echocardiography permits accurate and reliable determination of aortic valve area. Preoperative spatial recognition of the stenotic valve is possible by dynamic volume-rendered display.

Effects of prostaglandin E1 and buflomedil on left ventricular function in patients with severe chronic occlusive arterial disease: a prospective, randomized, double-blind trial.

In this study, the effect of a course of prostaglandin E ( 1 ) (60 microg/d intravenously [i.v.]) or buflomedil (150 mg/d i.v.) treatment on parameters of left ventricular systolic function was investigated by echocardiography in patients of comparatively advanced age with severe peripheral occlusive arterial disease (Fontaine's stage III or IV). The study population was 20 patients, 12 men and 8 women, between 51 and 85 years of age (average age, 73. 7 years), with multiple coexisting medical conditions. These patients were no longer suitable candidates for other forms of interventional or surgical treatment. The patients were treated with prostaglandin E ( 1 ) or buflomedil in the dosages recommended for peripheral occlusive arterial disease for 3 weeks. The following were determined on the 1st, 11th, and 21st day, before and after drug administration: end-diastolic and end-systolic volume, ejection fraction, and pre-ejection period/left ventricular ejection time ratio. The data from all 20 patients were included in the evaluation. There was no evidence of any significant change in the ejection fraction or systolic time intervals, suggesting the safety of the drugs in this special patient population with multiple coexisting conditions.

[Prospective study of subjective stress caused by dobutamine stress echocardiography--effect on diagnostic accuracy]. / Prospektive Untersuchung zur subjektiven Beeinträchtigung durch die Dobutaminbelastungsechokardiographie--Auswirkung auf die diagnostische Sicherheit.

UNLABELLED: We used a standardized questionnaire to assess physical and mental distress caused by dobutamine stress echocardiography (DSE). The examination was performed according to a standardized protocol (5-40 micrograms/kg/min including atropine). 91 patients (pts), 68 men (62 +/- 9 years), 23 women (65 +/- 7 years) were asked to quantify the severity of the following symptoms: palpitations, anxiety, headache, nausea, discomfort of left lateral position, angina pectoris and dyspnea. Numbers on a rating scale from 1-10 defined the degree of distress. Absence of a symptom equalled mark, 1, slight expression marks 2-4. Moderate expression was defined by marks 5-7 and very strong expression by marks 8-10. RESULTS: 86% of pts felt affected by one or more symptoms to a slight to moderate extent (mark 4 +/- 2.17). Palpitations were felt by 85% of the pts (mark 6 +/- 2.83), anxiety by 42% (mark 3 +/- 2.5), headache by 50% (3 +/- 2.54), nausea by 20% (2 +/- 1.72), angina pectoris by 42% (3 +/- 2.5), dyspnea by 30% (2 +/- 2.42) and discomfort of left lateral recumbent position by 43% (mark 3 +/- 2.59). 43 pts underwent coronary angiography. The negative predictive value of DSE to identify pts without a coronary artery stenosis extending a 50% diameter reduction was 85% for the 16 pts who reached their individual submaximal heart rate compared to 60% for those 27 pts who did not reach it. Unspecific symptoms led to test termination in these pts. The positive predictive values were comparable (89 and 94%). CONCLUSION: DSE causes physical and mental distress. If symptoms lead to test termination before age corrected submaximal heart rate is reached, normal wall motion does not exclude significant coronary artery disease.

Echocardiographic visualization of anomalous left main coronary arteries originating from the right sinus of Valsalva.

We report on two patients in whom the anomalous left main coronary artery arising from the right sinus of Valsalva with a septal course could be visualized by transthoracic echocardiography. It appeared as a small echo-free space, anterior to the aorta in the short parasternal axis. If the left main coronary artery arises anomalously from the right sinus of Valsalva, it can take four different courses until it branches into the left anterior descending and the circumflex coronary artery. The course between aorta and pulmonary trunk can be differentiated into an interarterial and a septal course using angiographic criteria. The interarterial course is a potentially life-threatening anomaly due to a high rate of myocardial infarction and sudden cardiac death. Echocardiography alone seems not to be able to distinguish between the potentially life-threatening interarterial and the benign septal course, as in our patients.