Biomedical subjects

H Sievert

Publications and source records attributed to H Sievert.

At least 91 records · Page 5Linked to original sources

PubMed1989

[Coronary arteriography with a plasma-isotonic roentgen contrast medium: effects on ECG, blood pressure and coronary circulation].

The nonionic-dimeric compound lotrolan (0.27 osmol/kg, 280 mg J/ml) is the first contrast medium with plasma-isotonic osmolality and sufficient iodine content for intravascular use. In 15 patients with coronary heart disease, the cardiac side effects of 1) lotrolan, 2) nonionic-monomeric lopromide (0.77 osmol/kg, 370 mg J/ml and 3) ionic-monomeric Amidotrizoate (2.1 osmol/kg, 370 mg J/ml) were compared intraindividually following randomized left coronary artery injections (8 ml). Electrocardiographic indices, aortic pressure, coronary sinus flow (thermodilution method), and coronary vascular resistance were determined before, during, and 60 s after each injection. Heart rate remained almost unchanged with lotrolan (+/- 3%) and lopromide (-8%). Amidotrizoate (-16%), however, caused a significant bradycardia. Aortic pressure decreased markedly after Amidotrizoate (-12%) but only moderately after lopromide (-7%) and lotrolan (-6%). Coronary sinus flow increased to the same extent with lopromide (+66%) and Amidotrizoate (+72%), but less with lotrolan (+43%). Coronary vascular resistance dropped significantly more following lopromide (-38%) and Amidotrizoate (-43%) than after lotrolan (-27%). As opposed to Amidotrizoate and lopromide, lotrolan caused only slight changes in heart rate, blood pressure, and coronary hemodynamics, presumably due to its plasma-isotonic osmolality. Only minor differences were found between the cardiac effects of Amidotrizoate and lopromide. The diagnostic quality of the angiograms, however, was better with Amidotrizoate and lopromide. Thus, due to its reduced cardiac side effects, lotrolan may only be useful in the case of experimental investigations applying digital techniques.

Adult↗

PubMed1988

[Opening of chronic coronary artery occlusions with a recanalization catheter].

Percutaneous transluminal angioplasty for recanalization was attempted for 44 chronic coronary arterial occlusions in 41 patients (two occluded vessels in three patients). In 11 instances the occlusion could be passed with a guide-wire. In the other 33 this was not possible. In 25 of them a 3, 4 or 5 F recanalization catheter, its end tapered to 2 or 3 F, was used. In this way re-opening was possible in 17 cases (68%). The catheter made it possible to splint or stiffen the guidewire to keep it straight, superselectively inject contrast medium, measure the pressure distal to the occlusion, and gradually bougie-like enlarge the resulting subtotal stenosis. A total of 28 of 44 coronary occlusions were re-opened (64%). All these patients were functionally improved. At subsequent angiography (a mean of 3.6 months later) 22 of 25 vessels had remained open, but ten had narrowed and three had become re-occluded.

Adult↗

PubMed1988

[Transfemoral closure of the duct of Botallo. Acute and long-term results].

A persistent ductus arteriosus was occluded with an Ivalon plug via a catheter delivery system, introduced through the femoral artery, in 38 patients, aged 11-72 years (mean 39). The mean diameter of the ductus was 4.5 +/- 1.2 (2-9) mm, mean pulmonary artery pressure 30/12 (15/5-70/27) mm Hg. In two patients the plug became dislocated after two and seven weeks, respectively, without serious consequences. In all others the occlusion was successful and permanent. There were only a few complications and none was serious. During a follow-up period of up to four years there were no instances of recanalization or further plug dislocation.

Adolescent↗

PubMed1988

[Long-term results of transluminal valvuloplasty in calcified aortic valve stenosis].

Transluminal valvuloplasty (TVP) was attempted in 11 patients, aged 38-82 years, with calcified aortic valve stenosis (AS). The transvalvular systolic pressure gradient was reduced from a mean of 91 +/- 28 to 44 +/-30 mm Hg. Two patients had needed an emergency with decompensated AS in cardiogenic shock, died during the operation, another died of the consequences of an endocarditis. One patient had an inadequate TVP: a renewed TVP was subsequently performed at another hospital, followed by an operation for severe aortic regurgitation produced by the second TVP. In four patients left-heart catheterization 3-12 months post-dilation demonstrated considerable restenosis. One patient was significantly improved clinically (but no angiography had as yet been performed) four months after the TVP. Doppler echocardiography in this patient, too, demonstrated renewed increase in transvalvular pressure gradient. The results demonstrate that, because of the high rate of recurrence, TVP is at present only rarely indicated for calcified AS.

Adult↗

PubMed1988

[Reopening of long-segment occluded aortocoronary venous bypasses. Short- and long-term results].

Recanalization of an occluded aortocoronary vein bypass was achieved in six out of seven patients (aged 57 +/- 4 years) 3-40 months after operation and 2-16 weeks after occlusion. The recanalization was done with a specially modified catheter introduced into the stump of the occluded vessel: urokinase was infused followed by balloon dilatation. Subsequent treatment included administration of nitrates, calcium antagonists, aspirin and heparin for at least three months. Repeat coronary angiography after 3-6 months (mean 4.3 +/- 1.0 months) demonstrated vessel patency in four of the six bypasses. One of them, severely stenosed, was again successfully dilated. It is concluded that bypass recanalization can be attempted if the occlusion occurred only a few weeks previously, angiography demonstrates a bypass stump and the state of the peripheral coronary artery makes good outflow likely.

Angioplasty, Balloon↗

PubMed1988

[Digitalis therapy in chronic heart failure. Digitoxin in patients in sinus rhythm pretreated with diuretics].

Eight patients in sinus rhythm with chronic heart failure were studied. After individually adjusted six-week treatment with diuretics (hydrochlorothiazide-triamtere and/or frusemide) all patients were clearly improved symptomatically. Subsequently they additionally received digitoxin for six weeks, 0.07-0.1 mg daily. Before and at the end of the digitoxin period cardiac volume was determined radiologically, echocardiography was performed and haemodynamic parameters determined at rest and on exercise via indwelling catheters. During digitoxin administration there was a slight increase in cardiac output from 4.63 +/- 0.82 to 5.05 +/- 0.98 l/min (P less than 0.1) at rest and from 7.22 +/- 1.94 to 7.79 +/- 2.59 l/min at rest. The mean values of all other haemodynamic parameters remained unchanged. These results suggest that in patients with chronic heart failure and sinus rhythm any clinical or haemodynamic improvement achieved will not be significantly bettered by digitoxin.

Adult↗

PubMed1988

Coronary hemodynamics during left and right coronary arteriography with an ionic and nonionic contrast medium.

The direct effects of ionic amidotrizoate (iodine content 370 mg/ml, osmolality 2.1 osmol/kg) and nonionic iopamidol (iodine content 370/ml, osmolality 0.8 osmol/kg) on the coronary circulation were intraindividually compared in 10 patients suffering from coronary heart disease. In accordance with a double-blind, crossover protocol, both contrast media were injected into the left and right coronary arteries (8 ml and 5 ml per injection, respectively). Injections of both dyes into the left coronary artery caused a similar decrease in heart rate. The prolongation in the QT interval was significantly greater after amidotrizoate (p less than 0.05). Systolic (p less than 0.01) and diastolic (p less than 0.05) aortic pressures decreased to a greater extent following amidotrizoate injection. Each contrast agent produced a similar increase in coronary sinus flow, but iopamidol resulted in a smaller decrease in coronary vascular resistance (p less than 0.05). After right coronary artery injections, both contrast media caused bradycardia and prolongation of the QT interval, a decrease in systolic and diastolic aortic pressure, a rise in coronary sinus flow, and a lowering of coronary vascular resistance. Though most changes were more pronounced following amidotrizoate injection, the differences in the ionic and the nonionic agent were not statistically significant. Thus, after selective coronary arteriography, both contrast media caused a transient drop in coronary vascular resistance and a rise in coronary sinus flow despite a decrease in aortic pressure. The effects of amidotrizoate were more marked, which might be attributed to the higher osmolality of this ionic contrast medium. Coronary hemodynamics, however, usually returned to baseline values within 1 minute.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiography↗

PubMed1988

Effects of 5 mg sublingual nitrendipine in patients with precapillary pulmonary hypertension due to pulmonary fibrosis.

In 10 patients with precapillary pulmonary hypertension due to pulmonary fibrosis, the arterial blood pressure, right heart hemodynamics, cardiac output, and arterial oxygen partial pressure were measured to evaluate the benefits of acute sublingual (5 mg) nitrendipine. Additionally, the effect of oxygen enriched air was compared to control. At rest, nitrendipine significantly diminished arterial blood pressure [102 +/- 3 to 93 +/- 3 mm Hg (mean +/- SEM)], right atrial pressure (5.7 +/- 0.9 to 3.4 +/- 0.8 mm Hg), mean pulmonary artery pressure (33.4 +/- 3.5 to 29.8 +/- 3.3 mm Hg), and pulmonary artery wedge pressure (13.0 +/- 2.0 to 6.8 +/- 0.8 mm Hg). During exercise, nitrendipine reduced mean pulmonary artery pressure (54.5 +/- 4.8 to 49.3 +/- 4.7 mm Hg) and right atrial pressure (9.3 +/- 1.3 to 6.8 +/- 1.4 mm Hg). A diminuation of arterial partial oxygen pressure did not occur at rest (63.2 +/- 3.8 mm Hg) or during exercise (50.9 +/- 5.1 mm Hg). Thus, nitrendipine causes a slight but significant improvement of right heart hemodynamics. The occurrence of arteriovenous intrapulmonary shunting due to vasodilatating effects of nitrendipine can be excluded. Also, nitrendipine can safely be used in combined arterial hypertension and pulmonary fibrosis.

Administration, Sublingual↗

PubMed1988

[Aortic isthmus stenoses--dilatation in adulthood. A German cooperative study].

An analysis of percutaneous transluminal angioplasty of the coarctation of the aorta in adults was evaluated in a cooperative study of the German Working Group of Angioplasty of the German Society of Cardiology. Dilation was performed in 18 patients with a mean age of 26 years (14-49 years). The success rate (gradient less than or equal to 20 mm Hg) was 78% regarding peak to peak gradient, 89% regarding mean gradient. The peak-to-peak gradient decreased from 82 +/- 16 mm Hg to 18 +/- 11 mm Hg. The diameter of the aortic isthmus increased from 0.7 +/- 0.3 cm to 1.3 +/- 0.4 cm (p less than 0.01). After six months only one restenosis occurred. The peak-to-peak gradient measured 10 +/- 12 mm Hg, the diameter 1.4 +/- 0.5 cm. In two patients a balloon rupture occurred without rupture-related complications. No patients died, no cross paralysis or aortic rupture occurred. In three of seven patients with trans-esophageal echocardiographic monitoring a small intimal flap was found; in one patient a media dissection occurred leading to a 15-min period of chest pain and spontaneous healing. In another patient successful dilation was controlled by acute control aortography and computer tomography. After discharge severe chest pain developed. A subtraction angiography of the aorta was negative. Six months later a biplane aortography of the distal thoracic aorta confirmed the diagnosis of aortic dissection type III DeBakey, previously diagnosed by transesophageal echocardiography.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1988

[A catheter for imaging the persistent ductus arteriosus].

Nonsurgical techniques for patent ductus closure require precise knowledge of ductus diameter, length and shape. Angiographic visualization, especially in adults, may be difficult, due to the high flow and overlap of the aorta or the pulmonary artery. We have developed a new catheter for visualizing a patent ductus without intraarterial injection of contrast dye. A smooth latex balloon is mounted near the tip of this catheter and when it is filled with dye, the balloon fits the contours of the ductus. Ductus diameter may be established by measuring the diameter of the balloon. Furthermore, the hemodynamic consequences of ductus closure may be observed with the balloon occluding the ductus.

Adolescent↗

PubMed1988

[Quantitative coronary angiography: methodologic principles of a densitometric procedure].

In a defined short segment of a coronary artery, the amount of contrast medium depends on the cross-sectional area of the artery. The density of the coronary angiogram in the corresponding region reflects the amount of contrast medium. During projection of a single coronary angiographic frame, light intensity at the respective region can be measured by means of a light sensor. In phantom studies, light intensity was proportional to the amount of contrast medium in the corresponding area. This was the case even after dilution of the contrast medium (correlation coefficient r = 0.96-0.99). In a concentric stenosis model, a good correlation was found between the real cross-sectional area and the cross-sectional area measured by densitometric analysis (r = 0.97). Even in the model of eccentric stenoses, the correlation was linear (r = 0.96). Thus, it seems basically possible to densitometrically measure the cross-section of a coronary stenosis in relation to a normal segment. Unlike video densitometry, this method requires only very little apparatus.

Absorptiometry, Photon↗

PubMed1988

[Results of balloon valvuloplasty in pulmonary valve stenosis].

Percutaneous balloon pulmonary valvuloplasty was performed in 17 consecutive patients, ranging in age from eleven years to 67 years (mean age: 40 +/- 17 years). The peak to peak pressure gradient was reduced by 16 to 167 mm Hg, the mean pressure gradient decreased from 99 +/- 42 to 46 +/- 22 mm Hg. In six patients there was a pressure gradient above 50 mm Hg after the procedure. Within three months it decreased due to regression of infundibular hypertrophy and ranged from 26 to 46 mm Hg after one year. There were no serious complications. One patient experienced a brief episode of syncope. Another patient developed a pulmonary incompetence which was without hemodynamic significance. Percutaneous balloon pulmonary valvuloplasty offers an alternative method for treating pulmonary stenosis not only in children but also in adults.

Adolescent↗

PubMed1987

[Coarctation of the abdominal aorta. Experiences with transluminal angioplasty].

Balloon dilatation was performed transfemorally in three patients suffering from coarctation of the abdominal aorta. In two cases the pressure gradient could be reduced markedly from 85 to 55 and from 72 to 32 mm Hg, respectively. At follow-up angiography 3 months later the gradient was reduced further to 12 and 5 mm Hg, respectively. One women patient who had previously been handicapped by claudication intermittens, was free from complaints after balloon dilatation, whereas the other women patient with suprarenal stenosis of the aorta and renal hypertension was normotensive subsequent to balloon dilatation. In the third (male) patient who had already been operated on earlier because of stenosis of the aortic isthmus, dilatation was unsuccessful even if a very high balloon pressure was applied. These experiences support the view--in agreement with other authors--that balloon dilatation in coarctation of the abdominal aorta is a method of low invasiveness that should be attempted before surgery is performed.

Adult↗

PubMed1987

[Transluminal angioplasty of aortic isthmus stenosis in juveniles and adults].

Percutaneous transluminal balloon angioplasty of coarctation of the aorta was performed on eleven patients, aged 5-35 years (mean 25 years). Three patients had had surgical resection of the coarctation previously. There were no complications. The balloons used had a diameter up to 20 mm and were inflated with pressures of 3-5 bar for 10-60 sec. In two of the preoperated patients dilatation did not succeed. It was successful in the remaining nine. In these patients the gradient was reduced from a mean of 58 +/- 17 to 18 +/- 11 mm Hg, the stenosis diameter being increased from 4.5 +/- 2.4 to 11.9 +/- 5.1 mm. In five of six patients, angiography three or twelve months postoperatively demonstrated persisting dilatation. It is concluded that this procedure can be successfully used in both juveniles and adults, not only in children.

Adolescent↗

PubMed1987

[Therapy of latent cardiomyopathy with verapamil].

In an open, randomized cross-over trial lasting two months, 21 patients with latent cardiomyopathy were either untreated or received verapamil 120 mg three times daily. Angina and dyspnea improved in 14 of the 21 patients. These symptoms worsened in one, remained unchanged in six (P less than 0.05). During exercise the pulmonary artery diastolic pressure fell from a mean of 25.3 +/- 7.6 to 20.1 +/- 6.6 mm Hg (P less than 0.05); (at rest, from mean of 10.7 +/- 5.2 to 9.0 +/- 4.5 mm Hg - not significant). In nine patients with a raised resting PA diastolic pressure verapamil produced a significant reduction (from 15.4 +/- 2.7 to 11.1 +/- 4.1 mm Hg) (P less than 0.05). All other hemodynamic parameters remained unchanged. These clinically and hemodynamically favorable effects are possibly due to improved diastolic ventricular function by verapamil. In latent cardiomyopathy any impairment of diastolic relaxation may be more important pathogenetically than reduction in systolic ventricular function.

Adult↗

PubMed1987

[Transfemoral valvuloplasty using the balloon catheter in mitral stenosis].

In two female patients (59 and 30 years old) with mitral stenosis, a successful valvuloplasty was carried out with a balloon catheter. After transseptal puncture with determination of the pressure gradient between the left auricle and the left ventricle, the atrial septum was initially dilated with a small balloon and a MediTech balloon catheter with a diameter of 25 mm was pushed forward into the region of the mitral valve via a guide wire. On filling of the balloon, the marked indentation at 3-4 atü hyperbaric pressure initially present could be eliminated. The pressure gradient fell from 8 mm Hg to 2 mm Hg in the first patient and from 12 mm Hg to 3 mm Hg in the second patient. The interventions were without complications. There was a marked clinical improvement with increase of physical exercise tolerance and decrease of dyspnoea in both patients. A mitral valve insufficiency did not occur. The new technique may possibly constitute an alternative to surgical commissurotomy.

Adult↗

PubMed1987

[Transfemoral valvuloplasty in calcified aortic valve stenosis].

In a 55 year old male patient and a 67 year old woman with calcified aortic valve stenosis, a valvuloplasty was performed via the femoral approach using a large-lumen balloon catheter. The 55 year old patient, who had undergone an aortocoronary bypass operation some years ago, displayed the symptoms of a cardiogenic shock. A surgical intervention would have entailed an additional risk. In the second case, there was a raised risk for the operation in view of a coronary two-vessel disease and with regard to the patient's age. By filling the balloon catheter placed in the aortic valve, the pressure gradient could be reduced from 100 mm Hg to 40 mm Hg, and in the second case from 95 mm Hg to 45 mm Hg. The slight aortic insufficiency which had been previously present in the two cases did not increase appreciably. The symptoms of cardiogenic shock disappeared, and there was a distinct clinical improvement. Valvuloplasty is evidently a possible method of treatment (even if it is palliative) in calcified aortic valve stenosis.

Aged↗

PubMed1987

[Measuring the intracoronary pressure gradient--value and methodologic limitations].

Measurements of pressure gradients were performed in a fluid-filled model. The hydrostatically regulated perfusion pressure, as well as the diameter of the tube segments and the regulation of the flow by peripheral resistance, were comparable to conditions in human coronary arteries. Pressure gradients above 20 mm Hg were only measured with a reduction in cross-sectional area of more than 90%. Even after increasing the flow four-fold, which corresponds to the human coronary flow reserve, as well as after probing the stenosis with different catheters (2F-5F), gradients greater than 20 mm Hg were only recorded with high-grade stenoses (more than 80% reduction in cross-sectional area). The findings in this model demonstrate that measurement of pressure gradients allows only a quantitative differentiation between high-grade (greater than 80%) and low-grade (less than 80%) stenoses. The catheter itself can substantially contribute to the gradient by vessel obstruction, depending on the diameter of the catheter and of the coronary vessel. A quantitative assessment of the stenosis therefore requires knowledge of the pre- and post-stenotic vessel diameter as well as of the catheter diameter. However, pressure measurements during transluminal coronary angioplasty should not be abandoned. They can be useful to aid catheter positioning and to estimate dilatation efficacy. Moreover, measurement of coronary capillary wedge pressure during balloon expansion provides valuable information about the extent of collateralisation.

Angioplasty, Balloon↗