[Arterial hypertension and blood pressure profile in patients with Williams-Beuren syndrome]. / Arterielle Hypertension und Blutdruckprofil bei Patienten mit Williams-Beuren-Syndrom.

The prevalence of hypertension and the diurnal blood pressure pattern were investigated in patients with Williams-Beuren syndrome (WBS) by blood pressure measurements in 142 children, adolescents, and young adults (female n = 62, male n = 80; median age 6.5 years (0.1-34.3 years)) and evaluation of ambulatory blood pressure data from 45 patients (female n = 21, male n = 24; median age 7.8 years (1-23.8 years)). Measurements revealed systolic hypertension in 46.5% of 142 patients, diastolic hypertension occurred in 36.6% (i.e. actual pressure > 95 percentile). According to the ambulatory data 42.2% of 45 patients had hypertension (mean arterial pressure > normal + 2SD). The nocturnal decline of the blood pressure was normal in hypertensive patients but reduced in normotensives (p < 0.01 vs normals). Males were more often hypertensive than females (46% vs 38%). Hypertensives had a higher body mass index than normotensives (19.5 vs 16.6 kg/m2, p < 0.05). In normo- and hypertensive WBS patients mean heart rates were elevated during day- and nighttime (p < 0.02 vs normals) the latter due to a reduced nocturnal decline. The prevalence of hypertension in WBS patients amounts to about 40%, thus being four- to eight-fold in comparison to healthy young adults or children. The diurnal blood pressure pattern and the elevated heart rates indicate that an increased arterial stiffness due to the vascular disease in the WBS and augmented sympathetic activity might play a role in the genesis of hypertension. Thus, effective antihypertensive treatment is likely to become difficult. From our experience beta-blocking agents are often successful in hypertensive WBS patients.

[Effects of age in the correction of isthmus stenosis on postoperative stiffness of the aorta]. / Bedeutung des Alters bei Korrektur einer Isthmusstenose für die postoperative Steifheit der Aorta.

Operative surgery for coarctation aims to eliminate the narrowed segment of the aorta and to restore a normal function of the aortic Windkessel, which depends on normal elastic properties of the aorta. To evaluate the effect of age at coarctectomy on the postoperative aortic elasticity, parameters of regional wall stiffness within the aortic arch were determined in 24 children after coarctectomy by means of echocardiography and blood pressure measurements. Actual data were compared with reference data (mean value normalized to body weight: mn +/- SD) obtained from n = 43 children, adolescents and young adults (age 1 month to 28 years; mean 12.6 years): elastic modulus Epn = 0.20 +/- 0.07 Mdyn/cm2/kg0.11; stiffness index beta = 3.45 +/- 1.3; diameter Dn = 0.52 +/- 0.08 cm/kg0.37. The results revealed that 4.9 years (mean) after coarctation repair within the first year of life (mean 3.2 months, n = 10) the parameters of elasticity and the diameter did not differ from normal. In those n = 5 children operated on in the age of 4.7 years there was a tendency towards increased aortic stiffness and reduced diameter 8.9 years later. In n = 9 children with a mean age of 9.2 years at operation the elastic modulus was increased 7.6 years later: Epn = 0.28 +/- 0.11 Mdyn/cm2/kg0.11; (p < 0.01). The diameter of the proximal aortic arch was significantly reduced (DN =0.42 +/- 0.08 cm/kg0.37., P < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Three decades of follow-up of aortic and pulmonary vascular lesions in the Williams-Beuren syndrome.

The diagnostic criteria of the Williams-Beuren syndrome (WBS) were established almost 3 decades ago. Until now there has been little knowledge about the natural and post-surgical history of vascular lesions in this syndrome. In order to evaluate the long term follow-up of aortic and pulmonary vascular lesions, we have analysed the catheterization data, angiocardiograms, and Doppler-echo measurements in 59 patients who were seen at least twice in our institution between 1961 and 1993. Their follow-up periods ranged from 2.1 to 28.2 years. Of 45 patients with supravalvular aortic stenosis (SVAS) with a mean follow-up period of 12.9 years, it became evident that pressure gradients of less than 20 mm Hg in infancy generally remained unchanged during the first two decades of life. Pressure gradients exceeding 20 mm Hg increased from an average of 35.5 mm Hg to 52.7 mm Hg in 13 patients. Of these, 8 required surgical relief of the narrowing. In 7 patients aortic hypoplasia was documented. In 5 of them the caliber of the aorta showed a tendency towards normalisation within a period of 11.9 to 23.9 years. Of 6 individuals with aortic hypoplasia and surgical relief of SVAS, 4 patients developed restenosis at the distal end of the aortoplasty patch. In contrast, 9 patients with operated SVAS-but without aortic hypoplasia-remained free of restenosis over a period of 11 years (mean). Coarctation occurred in 4/59 patients; restenosis was seen in 2 after 5 and 16 years. Peripheral pulmonary stenosis was followed in 23 patients over 14.4 years (mean).(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of increased wall thickness on indices of left ventricular pump function in children.

OBJECTIVE: To investigate whether augmented chamber performance in children with a concentric hypertrophied left ventricle is due to increased myocardial shortening or a geometric effect of the thickened ventricular wall. DESIGN: Chamber performance in terms of fractional area change and myocardial shortening--that is, circumferential midwall shortening--were measured by cross sectional echocardiography in young people with normal left ventricles and those with concentric hypertrophy of the left ventricle. PATIENTS: 52 healthy infants, children, and young people (age range 3 1/2 weeks to 26 years; body weight 1.8-89 kg (mean 23.6 kg)) and 29 infants, children, and adolescents with ventricular hypertrophy (mean body weight 31.4 kg, age range 4 weeks to 18.7 years). MAIN OUTCOME MEASURES: Chamber areas, fractional area change, midwall circumferential shortening normalised to body weight. RESULTS: In the controls normalised reference values were: end diastolic cavity area, 1.47 (0.25) cm2/kg0.65; fractional area change, 0.56 (0.03); end diastolic myocardial area, 1.62 (0.25) cm2/kg0.55; midwall circumferential shortening, 0.21 (0.03). By comparison, the patients had normal chamber areas (end diastolic myocardial area, 1.57 (0.42) cm2/kg0.65), increased fractional area change, 0.68 (0.05) (P < 0.001), and normal midwall circumferential shortening, 0.21 (0.03). There was a significant relation between the degree of hypertrophy (in terms of end diastolic myocardial area) and pump function while midwall shortening remained constant: 0.08 x end diastolic myocardial area + 0.44 (r = 0.74, P < 0.001). CONCLUSIONS: The relation between myocardial shortening, wall thickness, and fractional area change emphasises that the augmentation of pump function variables in left ventricular hypertrophy in young people is an effect of the thickened wall and not necessarily due to increased myocardial shortening. This relation offers the possibility of assessing the adequacy of chamber performance with respect to the degree of hypertrophy.

[Valvular diseases of the right heart]. / Klappenerkrankungen des rechten Herzens.

Recently, the development of diagnostic and operative interventional techniques has contributed to the successful treatment of congenital valve lesions of the right heart. The clinical picture, diagnostic approaches, and therapeutic outcome are presented. In pulmonic valve stenosis the fusion of leaflets is most common. Stenosis severity corresponds to the intensity of the systolic murmur. Pressure gradients can be quantitated by Dopplersonography. Balloon valvuloplasty is the method of choice for treatment. Residual gradients (24-36 mmHg) are not significantly different from surgical results. In Tetralogy of Fallot the ventricular outflow tract obstruction and a subaortic septal defect are most characteristic, both of which can be visualized by echocardiography. Cyanosis and the pulmonary systolic murmur are typical findings. Complications due to hypoxemia are reduced by corrective surgery in early childhood. Arrhythmias and ventricular dysfunction may complicate the long-term prognosis. Pulmonary insufficiency mostly results from surgical relief of stenoses. It can be quantitated by densitometry and MNR. Even severe pulmonary insufficiency is well tolerated for decades; on the long-term its prognosis remains uncertain. In Ebstein's anomaly the leaflet attachment of the tricuspid valve is displaced into the right ventricle, which is best diagnosed by echocardiography. Symptomatology ranges from heart failure (infancy) to a systolic murmur only (childhood). Plastic recontruction of the tricuspid valve has become technically feasible.

[Functional angiocardiography]. / Funktionsangiokardiographie.

Recent development of powerful image processing systems provides computation of angiocardiographic image series. Thus, acquisition and display of specific cardiac and circulatory parameters has become feasible. The simplest processing mode utilizes repetitive image subtraction, for example for the documentation of left ventricular wall motion abnormalities. A qualitative aspect of organ perfusion (myocardium, lungs) is obtained by color coding of serial DSA-images. Quantitative studies of vascular perfusion, however, require complex parameter extraction techniques according to the theory of indicator dilution. Great advancements have been achieved for arterial flow distribution measurements to study peripheral vascular disease. The actual interest in cardiology concerns measurements of coronary flow reserve that are based either on perfusion time or contrast mass measurements. However, limitations in quantitative flow studies must be considered in relation to the physico-chemical effects of contrast media.

[Pulmonary embolism in early adulthood. Detection using intravenous subtraction angiography]. / Lungenembolie im jugendlichen Alter. Nachweis mit Hilfe der intravenösen digitalen Subtraktionsangiographie.

In female adolescents with pulmonary embolism such as in the presented 19 year old patient oral contraceptives have to be considered as an etiologic factor. It is important to consider this diagnosis even in that age group. The diagnosis can be verified by intravenous digital subtraction angiography.

Replacement of the aortic root by free implantation of a stentless aortic porcine bioprosthesis in a patient with aneurysm of the sinuses of Valsalva.

In a patient with aneurysms of the sinuses of Valsalva a stentless porcine bioprosthesis was implanted with excellent hemodynamic and clinical short-term results. The implantation technique was similar to the technique used for the implantation of a composite graft. The postoperative study revealed a pressure gradient of 7 mmHg between the left ventricle and aorta and no regurgitation. Although the implantation of a porcine aortic root including a part of the ascending aorta without any artificial stenting material is feasible, one should be aware of the specific technical difficulties due to the increased rigidity of the fixated tissue. To our knowledge this is the first report of an implantation of a stentless aortic root porcine bioprosthesis for the treatment of aneurysms of the sinuses of Valsalva.

Densitometric studies in digital subtraction angiography: assessment of pulmonary and myocardial perfusion.

The technical improvement of digital imaging systems has provided for roentgen densitometric analysis of radiographic image sequences. Thereby, regional and temporal measurements of the amount of contrast medium have been performed for comparative studies in angiocardiography. The use of digital image subtraction for densitometric evaluation is specifically advantageous because misregistration by motion artefacts can be circumvented. Furthermore, enhancement of faintly opacified circulatory structures assists in the detection and outlining of the regions of interest. Methods of digital densitometry are described utilizing large "densitometric areas" for the evaluation of pulmonary perfusion symmetry. Similarly, coronary flow distribution data have been established in experimental studies. Regional measurements of myocardial contrast accumulation allowed for perfusion studies in absolute units of volume flow (ml/min) of the three main coronary arterial vessels. Future application of the latter technique is expected to facilitate coronary flow reserve measurements in the clinical setting.

[Experimental measurements of renal circulation using digital functional angiography]. / Experimentelle Nierendurchblutungsmessungen mit der digitalen Funktionsangiographie.

New techniques of digital image processing have been experimentally tested for the assessment of renal blood flow. The underlying principle in functional angiography is the extraction of flow parameters. Basically, density-time variations of the contrast medium are analyzed from each picture element of a 256 X 256 matrix. The real-time acquisition rate of images was 25/sec. For the calculation of angiographic flow a PDP 11/40 computer was used to interactively perform a time dependent segmentation of the renal arteries and the aorta. Subsequently, volume flow was calculated in relative units for the specific vascular segments under study. 15 control angiograms were made in 5 animals with cardiac output ranging between 0.8 to 2.2 l/min. Unilateral renal blood flow was calculated as 24 +/- 3.4% of pre-renal aortic flow without systematic side differences. Reproducibility from repeated flow measurements showed an SD of +/- 1.8% of the individual pre-renal aortic flow. Renal flow was also measured in 3 animals with an experimentally created 50% flow reduction of the left kidney. Angiographic flow in the left renal artery dropped to 12 +/- 2% of pre-renal flow. The present experimental data suggest that digital angiography has sufficient diagnostic capabilities for the detection of abnormal renal blood flow. The technique may serve as a useful diagnostic adjunct to conventional angiography and has the potential of assisting in the evaluation of renal vascular hypertension.

Parametric imaging.

The analysis of circulatory dynamics by functional data extraction from radiologic image sequences constitutes the latest development of digital imaging techniques in angiography. In this article, the methodologic approach of angiographic parameter extraction and the interpretation of functional information are outlined. Applications of parametric imaging in arterial blood flow, arterial flow distribution, parenchymal perfusion, and coronary and myocardial perfusion are discussed.

Orthotopic transplantation of aortic valve allografts. Early hemodynamic results.

The aortic root as a functional unit includes the sinuses of valsalva, valve ring, the leaflets and the commissures. This unit is impaired by the insertion of a bioprosthetic three-leaflet valve. Moreover, bioprostheses fail because of fatigue and flexion stresses. Consequently a program was started for free-handed orthotopic transplantation of allogeneous aortic valves at the Department of Cardiovascular Surgery, University Kiel. A series of 16 consecutive antibiotic, sterilized aortic valve allografts were transplanted in the last 12 months without death. There were 4 females and 12 males between 18 and 63 years old (mean 47.9). The dominant lesion was aortic regurgitation (in 9), stenosis (in 3) and mixed (in 4). Out of the 13 patients who maintained their allografts, 10 (77%) were in class III and 3 (23%) in class IV of the NYHA functional classification. Four patients improved from class III to class I, and 9 from class III and IV to class II of the NYHA functional classification after surgery. All patients except one had postoperative recatheterization including videodensitometry to quantitate the regurgitation, expressed as a regurgitant fraction ( RGF ) in percent of the total stroke volume of the left ventricle, and pressure measurements to determine systolic gradients across the aortic valve allograft, 3 to 6 days and 9 months after surgery. Eleven (68.75%) patients had no regurgitation, 2 (12.5%) patients had trivial aortic regurgitation with RGF of 7% and 10%, respectively. Three (18.75%) patients had severe aortic valve regurgitation with RGF between 40% and 60% due to technical errors and their allografts had to be replaced.(ABSTRACT TRUNCATED AT 250 WORDS)

Digital angiography in the diagnosis of congenital heart disease.

Based on experimental and clinical studies, the technical aspects (choice of projection, injection technique), experimental and clinical results, and the indications for computerized digital angiography in congenital heart disease are reviewed. To obtain high-quality diagnostic images consistently, ECG-gating, suspended or gated respiration, and short pulsewidth acquisition are required. Clinically useful diagnostic information has been acquired in children with suspected functional murmurs, cardiac surgery that is believed to be inadequate, and in cyanotic newborns after intravenous injection of contrast material. Increased diagnostic information has also been obtained after intracardiac injection of small amounts of contrast and computerized digital processing of images in children undergoing cardiac catheterization.

[Digital function angiography. A method of measuring arterial blood flow]. / Digitale Funktionsangiographie. Eine Methode zur arteriellen Durchblutungsmessung.

Digital image processing techniques can be effectively used for the quantitative evaluation of angiograms. In this study, the principle of parameter extraction from digitized image series was utilized. The procedure of parametric analysis was based on mathematical calculations of density-time-curves of the contrast medium according to each picture element of a digital image matrix (256 x 256 picture elements). Flow measurements were calculated from time parameter data and the subsequent segmentation of vessels indicating the propagation of the contrast medium within given time intervals. Flow velocity and volume flow studies will provide additional quantitative information to the evaluation of conventional angiograms.

Assessment of left ventricular muscle volume by digital angiocardiography.

By means of digital image processing, the entire myocardial wall of the left ventricle could be visualized by biplanar angiocardiography in animal experiments using 14 pigs (weight, 16-25 kg). The resulting images of the myocardial wall allowed dimensional measurement by videometry. The muscle volume was computed according to Simpson's rule for end diastole and end systole and compared with postmortem measurements. Replication of the procedure resulted in a 95% confidence interval of +/- 11% (+/- 5.6 ml) at maximum. Comparison with postmortem data showed highly significant correlations of r = 0.894 (end diastole) and r = 0.938 (end systole). This study points out that digital image processing allows a reliable assessment of myocardial volume from routine left ventricular angiocardiography. Besides early clinical applications, the method has been successfully used to visualize nonperfused segments of the myocardial wall in artificial infarction.

Use of digitized functional angiography to evaluate arterial blood flow.

Digital angiography (DA), being a computer-based imaging system, allows for manipulation of the image data. One potential use derived from data manipulation is the production of functional images or images that reflect a physiologic parameter in addition to anatomic information. A discussion is presented of the background work employed to derive blood flow measurements using DA images, including the theoretical and practical limitations of the methodology. While absolute blood flow is hard to determine by any noninvasive and many invasive methods, flow velocity and relative blood flow in large vessels is obtainable with small volumes of intraarterial contrast injection using the basic principles of indicator dilution techniques and evaluation of the time versus density relationships of contrast bolus. An appraisal of the functional imaging method is provided, including its drawbacks and the potential areas of application.

Intravenous angiocardiography using digital image processing. II. Detection of left-to-right shunts in an animal model.

Digital image processing was applied in an experimental model to study the feasibility of intravenous angiocardiography for the detection of cardiac lesions with left-to-right shunting. Methods were designed to produce ventricular and atrial septal defects (VSD, ASD) as well as patent ductus arteriosus (PDA) equivalent in pigs. After intravenous (IV) injection of 0.5-1 ml of Urografin 76% per kg body weight, digitization and computerized processing of roentgen video images recorded at a rate of 50 fields per second was performed. The radiographic images were recorded in the four-chamber view obtained by 30-35 degrees of caudocranial angulation and 50-60 degrees of left anterior oblique positioning of the animal. The processing of images included electrocardiogramgated background subtraction, rescaling, and sometimes histogram equalization. Integration of multiple background and multiple contrast images was performed in order to increase the signal-to-noise ratio. Ventricular septal defects and patent ductus arteriosus could be detected per se, while atrial septal defect only could be indirectly detected. Respiratory motion artifacts could be avoided by cross-correlation respiratory gating or by subtracting left ventricular end systole from end diastole during the same cardiac cycle of left ventricular opacification. The results of the experiments in pigs are the basis for continued clinical use of digitized IV angiocardiography.

Quantitative analysis of structure and function of the cardiovascular system by roentgen-video-computer techniques.

A survey of the evolution of roentgen-video-computer techniques is given which was initiated by the development of videodensitometry by Wood and his associates. Following fundamental studies of the usefulness and limitations of x-ray equipment for quantitative measurements and the applicability of the Lambert-Beers law to x-ray absorption, videodensitometry has been used experimentally and clinically for various circulatory studies and has proved to be particularly valuable for the quantitation of aortic, pulmonic, and mitral valvular regurgitation. The second offspring of these techniques, so-called videometry, uses dimensional measurements from single and biplane angiocardiograms for the assessment of size, shape, and contraction pattern of the heart chambers. Volumes of the right and left ventricles can be determined clinically with a standard error of estimate below 10%. On the basis of these studies, normal values have been derived for all age groups, and they depict geometric changes of the growing heart. Cardiac index and ejection fractions proved to be age-independent biologic constants. Finally, methods for complete digital processing of video-image sequences in an off-line and real-time mode are described which allow digital image storage and documentation, dynamic background subtraction for contrast enhancement, and intravenous angiocardiography, in addition to functional imaging by parameter extraction from a matrix of pixel densitograms. Wall thickness and motion determinations, regional flow distribution measurements, and various image-composition techniques are also feasible.

Intravenous angiocardiography using digital image processing: I. Experience with axial projections in normal pigs.

Computerized digitization and processing of roentgen video images was performed in four-chamber-view intravenous angiocardiography in normal pigs. Significant contrast enhancement was obtained through electrocardiogram-gated background subtraction and rescaling after integration of multiple background and contrast images. Histogram equalization and time parameter extraction or functional imaging was also used. The left and right heart were well visualized after intravenous injection of 0.5-1 ml Urografin-76% per kg of body weight. Image processing of left and right ventricular end diastolic and end systolic frames was performed as well as subtraction of right and left end systolic from end diastolic frames and subtraction of right from left heart frames. If left ventricular end systolic images were subtracted from end diastolic images, the left ventricle was seen without continuity with the left atrium. Through time interval difference processing, left ventricular wall motion per time unit could be studied. The results were the basis for subsequent experiments concerning detection of septal defects in pigs as well as clinical studies.