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Biomedical subjects

G Kober

Publications and source records attributed to G Kober.

At least 145 records · Page 8Linked to original sources
PubMed1986

[Results of combined myocardial scintigraphy and radionuclide ventriculography before and after transluminal coronary angioplasty of critical coronary artery stenoses].

This study compares exercise radionuclide ventriculography (RNVG) and exercise myocardial scintigraphy with 201Tl (MSC) both computed trisectorially. 137 patients before and after transluminal angioplasty (TCA) were investigated. While specificity equivalent was set at 90% for both methods (10% percentile of the controls [n = 29]) overall sensitivity for RNVG was 79% (n = 86) and for MSC 78% (n = 98). Sensitivity of RNVG for lesions of the posterior wall was lower than for the anterior wall: LAD stenoses 83% (n = 46), RCA stenoses 71% (n = 17), and LCX stenoses 63% (n = 8). Sensitivity of MSC presents only a slight difference between anterior and posterior wall lesions: LAD stenoses 78% (n = 51), RCA stenoses 73% (n = 22), RCX stenoses 100% (n = 8). Reproducibility of pathological findings before and after non-successful TCA and the determination of the stenosed vessel was slightly better with MSC than with RNVG. Functional improvement after a successful TCA is predictable by MSC, whereas RNVG documents the functional improvement.

Adult↗
PubMed1986

[Direct myocardial anti-ischemic effect of diltiazem in the human].

In a randomized double blind placebo-controlled study in 20 patients the influence of the calcium antagonist diltiazem (1.0 mg administered intracoronarily, distal from the stenosis) on the severity of myocardial ischemia during therapeutic coronary occlusion (transluminal coronary angioplasty) of the left anterior descending coronary artery was investigated. The severity and time of onset of ischemic ST and T wave changes as well as anginal pain were significantly reduced 3 and 8 minutes after diltiazem, whereas there was no definite change in the controls. Heart rate and blood pressure were not influenced by diltiazem or placebo. The results indicate a direct antiischemic effect of diltiazem on myocardial cells. The findings can neither be explained by an influence on cardiac afterload nor by coronary vessel reactions, nor a reduction of myocardial contractility. The findings do not permit conclusions in terms of the duration of this direct antiischemic mode of action.

Adult↗
PubMed1986

[Mechanism of action and long-term results of balloon dilatation of coronary vessel stenoses].

Predominant mechanisms for opening of coronary stenoses by balloon angioplasty are reduction of atheroma by fluid expression and increase in vessel diameter. Coronary dissection is related to complications like abrupt coronary closure but not to acute or long-term success. Local recurrencies after coronary angioplasty occur within the first 4 months. After this period long-term results depend on progression of the disease in other coronary arteries or segments.

Angioplasty, Balloon↗
PubMed1986

[The diameter of arterial and venous abdominal vessels during acute and chronic administration of nitrates. A sonographic study].

Fourteen male patients with coronary heart disease were randomly assigned to treatment periods with isosorbide dinitrate (ISDN) 120 mg/day (6 X 20 mg) and placebo for 4 weeks each, according to a double-blind protocol with intraindividual cross-over. The luminal diameters of the superior mesenteric artery, the hepatic artery, the superior mesenteric vein and the portal vein were determined sonographically in the supine position on days 1, 14 and 28 of both treatment periods 90 min after drug intake. The measurements were repeated after 1.6 mg sublingual nitroglycerin. On day 1 of drug intake the vessel diameters increased significantly after ISDN as compared to placebo: superior mesenteric artery: +11%; hepatic artery: +26%; superior mesenteric vein: +17%; portal vein: +11% (p less than 0.05). No differences in luminal diameters between both drug regimens were found on days 14 and 28. Additional nitroglycerin caused a marked diameter increase during the placebo period (14-21%; p less than 0.001) and on days 14 and 28 of ISDN therapy, while the drug effects were absent after maximal ISDN-induced vasodilatation on day 1. Thus, nitroglycerin and isosorbide dinitrate administered acutely caused a comparable vasodilatation of arterial and venous vessels in the splanchnic region. During sustained therapy with isosorbide dinitrate the vasodilatory effects of the drug were lost. It is supposed that a decrease of blood pooling in the splanchnic region occurs during sustained ISDN therapy. Despite this tolerance development to the circulatory effects of isosorbide dinitrate, nitroglycerin remained effective with regard to arterial and venous vasodilatation.

Adult↗
PubMed1986

[Hemodynamic side effects of an ionic and a nonionic roentgen contrast medium in patients with heart valve diseases and pulmonary hypertension].

The purpose of this study was to compare the hemodynamic side effects of an ionic and a nonionic contrast medium intra-individually. 20 patients with valvular heart disease (NYHA III-IV) and pulmonary hypertension (PPAsyst greater than or equal to 40 mm Hg) received injections of 40 ml iopamidol (0.8 osmol/kg) and 40 ml amidotrizoate (2.1 osmol/kg) into the right atrium. Heart rate and cardiac output, as well as right atrial, pulmonary-artery, pulmonary-capillary, and aortic pressures were measured. Peripheral and pulmonary vascular resistance and stroke volume were calculated. Right atrial pressure increased more after amidotrizoate (p less than 0.001). Pulmonary artery pressure was elevated with both contrast media to the same extent. An increase in aortic pressure was seen after iopamidol, while a decrease occurred after amidotrizoate (p less than 0.01). Amidotrizoate caused a more marked increase in heart rate (p less than 0.001) and cardiac output (p less than 0.001). Stroke volume was increased with both contrast media. Pulmonary vascular resistance decreased after amidotrizoate as well as after iopamidol, but systemic vasodilatation was more pronounced following injection of amidotrizoate (p less than 0.001). In general, iopamidol caused less hemodynamic side effects than amidotrizoate. Thus, nonionic low osmolality contrast media provide decreased risks in patients with valvular heart disease and elevated pulmonary artery pressures undergoing angiocardiography and intravenous digital subtraction angiocardiography.

Adult↗
PubMed1985

[Transluminal coronary angioplasty in patients with chronic kidney failure].

Six patients with chronic renal failure (two in the predialysis state; four chronically dialysed of whom two were after renal transplantation) were treated by transluminal coronary angioplasty for severe angina and ischaemic ECG changes. In 5 patients the successful dilatation of six stenoses resulted in good clinical and angiographic findings for a follow-up period of up to 3 years. One patient had to have an emergency bypass operation. If coronary revascularisation is indicated, transluminal coronary angioplasty is thus to be preferred to primary bypass operation in patients with chronic renal failure, because it is less invasive, relatively cheap and can be more easily repeated in case of recurrence or new stenoses.

Adult↗
PubMed1985

Relation of antianginal efficacy of nifedipine to degree of coronary arterial narrowing and to presence of coronary collateral vessels.

Thirty-six patients with chronic stable angina pectoris or with stable and vasospastic components of angina pectoris were classified by coronary arteriographic findings into 4 groups. Patients in group A had a single stenotic coronary artery; patients in groups B, C and D had occluded arteries, but these arteries had been collateralized to varying degrees, and an epicardial coronary steal phenomenon was possible. All patients underwent multiple exercise tests before and after randomized, double-blind, crossover treatment with 20 mg of nifedipine, 20 mg of isosorbide dinitrate, a combination of both, and placebo. Maximal and mean ST-segment depression, occurrence of angina pectoris and heart rate were evaluated. After nifedipine treatment, mean ischemic ST-segment depression was reduced 21% in group A (p less than 0.05), but was not significantly altered in the other groups (group B, 2% decrease; group C, 10% increase; group D, 3% decrease). However, isosorbide dinitrate reduced ST-segment depression significantly in all groups (group A, 29%, p less than 0.001; group B, 18%, p less than 0.01; group C, 19%, p less than 0.05; group D, 33%, p less than 0.05). The combination with nifedipine did not further improve the effect of isosorbide dinitrate. Maximal ST-segment depression and angina pectoris paralleled the changes in mean ST depression during the different medications. Heart rate at rest was not significantly changed after nifedipine treatment in any group, but increased significantly after isosorbide dinitrate treatment in groups B and C (group B, 12%, p less than 0.01; group C, 9%, p less than 0.05); heart rate during exercise did not differ significantly in any group or after any form of medication from placebo.

Adult↗
PubMed1985

Active and passive changes in coronary diameter after vasodilation with SIN-1, the active metabolite of molsidomine.

The vasodilating effects of intracoronary injections of 0.4 mg of SIN-1, the active metabolite of molsidomine, on epicardial coronary arteries and coronary stenoses were evaluated in 14 patients with coronary artery disease in a double-blind, randomized fashion vs placebo. Nine additional patients with well defined coronary stenoses received 0.4 mg of SIN-1 as well. Diameter changes of nonstenotic coronary arteries in proximal, medial, and distal coronary segments as well as changes of the residual luminal diameters within coronary stenoses were determined before (K), immediately after (M1), and 10 minutes after (M2) intracoronary administration of SIN-1. Aortic pressures and heart rate were monitored continuously. After administration of SIN-1, the diameters of nonstenotic coronary arteries increased in proximal segments by 9.4% (M1) and 11.7% (M2), in medial segments by 17.9% (M1) and 17.6% (M2), and in distal segments by 25.6% (M1) and 28.8% (M2). Within coronary stenoses the residual luminal diameters showed mean increases of 31.5% (M1) and 48.3% (M2). Placebo administration did not alter coronary diameters significantly. Aortic pressure and heart rate did not change after administration of SIN-1 or placebo. SIN-1 effectively dilates nonstenotic and stenotic coronary segments, as do nitrates and calcium channel blockers. By intracoronary injections, the direct effects on coronary vessels can be evaluated without interference with systemic effects. The increase in the residual luminal diameters within dynamic coronary stenoses after administration of SIN-1 is probably an important antianginal mechanism also for molsidomine.

Coronary Angiography↗
PubMed1985

Recurrence rate after successful coronary angioplasty.

Among 356 consecutive patients with successful TCA performed between October 1977 and June 1983 follow-up angiograms were performed in 333 patients (94%). A total of 439 follow-up angiograms at 1-48 (average 5.6) months after successful angioplasty were analysed. Restenosis rate was 12% if defined as remaining widening of less than 20% compared with the situation before angioplasty. It was 16% if defined as loss of at least half of the initial gain in luminal diameter, and 17% if defined as increase from immediate post-TCA-stenosis of much greater than 30% or the loss of at least half of the initial gain in luminal diameter. This value dropped to 15% if the subgroup of 30 patients with second TCA and of 14 patients with dilatation of an aortocoronary bypass stenosis were excluded; in both subgroups recurrence rate was higher (33% and 45%, respectively). The observed restenosis rate is less than 50% of that reported by the PTCA registry of the NHLBI. Several factors can possibly be responsible for the reduction in restenosis rate: selection of patients; technique of TCA; medical treatment during and after TCA; modification of risk factors, compliance of patients; unknown factors. Long-term medical treatment with acetyl salicylic acid, nitrates and calcium blockers in high doses is considered to be most probably responsible for the favourable results.

Angiography↗
PubMed1985

[Transluminal coronary angioplasty 1977-1985. Experience with 1000 interventions].

Transluminal coronary angioplasty (TCA) was introduced in 1977 for dilatation of coronary stenoses. From October 1977 to December 1984 1087 procedures have been performed in Frankfurt. The mean success rate was 77% with an increase from 58% to 84% since 1977. Recurrences were seen within the first year in 15% of the patients, which could be treated successfully in a high percentage with a second TCA. Emergency bypass operations were necessary in 5.2%. Four patients (fatality rate 0.37%) died as consequence of the intervention. Within few years TCA has become an established procedure for myocardial revascularisation, with a high success rate. Major progress has been possible in the last few years due to technical developments, which are still going on. They may lead to further improvement of the results and enlargement of the indication for TCA.

Adult↗
PubMed1985

[Percutaneous pulmonary valvuloplasty].

Five patients (aged between 11 and 59 years) with valvular pulmonary artery stenosis and pressure gradients between 60 and 143 mm Hg underwent percutaneous transluminal balloon valvuloplasty. Selection of the appropriate balloon size was based on the measurement of the dimension of the value anulus as a determinant from the angiogram. Balloon catheters were used with a diameter of 18 to 20 mm. After placement in the stenotic valve the balloon was filled with diluted contrast material for 10-20 s. The balloon indention by the stenotic valve disappeared suddenly during expansion with one to three atmospheres. The pressure gradient in individual patients decreased from 60 to 25, from 143 to 60, 100 to 55, 143 to 60, and 60 to 37 mm Hg, in the mean from 101 to 52 mm Hg. All patients were discharged two to four days after the procedure. During follow-up with recatheterization after three to nine months (four patients) the gradients decreased as compared to the value immediately after valvuloplasty. The exercise capacity increased in all patients. No complications were observed. Balloon valvuloplasty of pulmonary valvular stenosis seems to be an alternative to the operative procedure.

Adolescent↗
PubMed1985

[Long-term results of transluminal coronary angioplasty of chronic coronary artery occlusions].

In 43 patients an occlusion of the coronary artery, which had occurred a few weeks or months previously, was diagnosed between 1977 and 1983. Angiograms were available prior to the occlusion in 35 patients but not in 8 patients. In 31 patients mechanical revascularization was attempted with acute success in 42 percent of the patients. The primary success rate in a control population without occlusion but high-grade stenoses at similar sites was 83 percent. Reocclusions or high-grade restenoses occurred in 54 percent of the revascularized vessels. Taking into account successful repeated dilatations, 62 percent of the successfully treated patients showed long-term success a year after intervention. With reference to all patients in whom revascularization had been attempted, the long-term success rate was 26 percent. Hence, mechanical revascularization of subacute and chronic artery occlusions by angioplasty shows much less chance of acute success together with a markedly increased restenosis rate compared to angioplasty of chronic stenoses. Regarding the good long-term results in a quarter of patients, the technically unproblematic approach as well as minimal dangers for the patients, a revascularization attempt seems to be justified in corresponding clinical presentations.

Angina Pectoris↗
PubMed1985

[Acute cardiac side effects of iodecol, a new nonionic dimer roentgen contrast medium, in intracoronary injection].

The effects of intracoronary injections of Iodecol, a nonionic-dimeric contrast medium (iodine content 350 mg/ml, osmolality 0.34 osmol/kg, viscosity 13.8 mPa X s) on haemodynamics, coronary blood flow, ECG, and cationic content as well as osmolality of coronary sinus blood have been evaluated and compared to those of Iopamidol and Amidotrizoate. Experiments were carried out in 9 closed-chest dogs using heart catheterisation techniques. After Iodecol and Iopamidol only positive inotropism was seen while Amidotrizoate initially had cardiodepressive effects. Iodecol caused less increase of peak velocity of pressure rise and systolic blood pressure than Iopamidol. All contrast media led to an increase in coronary blood flow of the same extent. ECG changes were most marked following Amidotrizoate and only slight after Iodecol. Decrease of cationic content and increase of osmolality in coronary sinus blood were seen after each compound. Changes were only small after Iodecol and always greater after Amidotrizoate. Moreover, an overproportional decrease of coronary sinus calcium content was seen after Amidotrizoate due to calcium binding. Thus, based on these animal experiments, a further slight reduction of acute cardiac side effects during coronary arteriography could be expected from the use of nonionic dimeric compounds, compared to ionic and currently used nonionic contrast media.

Animals↗
PubMed1985

[The action of a new calcium antagonist 5,6-dimethoxy-2-(3 [(alpha-(3,4-dimethoxy)-phenylethyl)methylamino] propyl)-phthalimidine hydrochloride (AQ-A 39cl) on hemodynamics and ischemia parameters in exercise ECG of patients with coronary heart disease].

Six patients with angiographically documented coronary artery disease underwent multiple exercise tests before and after randomized double-blind crossover treatment with 200 mg 5,6-dimethoxy-2-(3[(alpha-(3,4-dimethoxy)phenylethyl)methylamino] propyl)-phthalimidine-hydrochloride (AQ-A 39 cl, in the following briefly called AQ-A 39) intravenously. Changes in ST-segment depression, angina pectoris, heart rate and blood pressure were evaluated. After AQ-A 39, the sum of ST-segment depression was significantly reduced compared with control and placebo by 48% (2p less than 0.025) and 42% (2p less than 0.05) respectively, maximal ST-segment depression by 45% (2p less than 0.025) and 35% (2p less than 0.05), respectively; the duration of angina pectoris was reduced by 50% and 33%, respectively. AQ-A 39 reduced heart rate at rest and during exercise; blood pressure, however, was not significantly altered. In conclusion, AQ-A 39 is an antianginal drug, which acts most probably by cardiac mechanisms and not by reduction of afterload. Thus, further studies about AQ-A 39 or its derivatives seem to be useful.

Adult↗
PubMed1984

[Coronary artery aneurysms].

Coronary artery aneurysms are rare and are diagnosed almost exclusively by angiography. Apart from a particular form of coronary artery sclerosis congenital malformations and various inflammatory diseases are to be considered aetiologically. Different opinions exist as to the clinical relevance and prognosis as well as to the necessary treatment of coronary artery aneurysms. Over the last 7 years we have observed 10 patients with in part grotesque dilatations of the coronary arteries. Based on the history and the other findings coronary sclerosis or/and congenital malformations had to be assumed. Follow-up of up to 6 years permits not an unfavourable prognosis which is more determined by the accompanying stenosing coronary sclerosis. Due to the danger of thromboses prophylaxis with platelet aggregation inhibitors is recommended. In dilated vascular disorders only surgery should be considered as the exception.

Adult↗
PubMed1984

[Occurrence and predictability of progression of high grade coronary vessel stenoses to occlusions].

The aim of this study is to evaluate the incidence and time of occlusions of high-grade coronary stenoses and to discover risk factors for the prediction of impending occlusions. At the time of scheduled angioplasty, on average within 4.5 months of the first diagnostic angiogram, 35 (6.5% of 650) vessels were already occluded. Another 5 patients had died on the waiting list and 2 had suffered a non-fatal infarction. In comparison to patients without progression of stenoses of a similar location and severity, special risk for the occurrence of occlusions was found in cases with collaterals, after infarctions (history, ECG, angiogram), and with multivessel disease. The prevalence of atherogenic risk factors was also higher. There are no clear differences between both groups as far as age, sex, nature and duration of symptoms, angiographic morphology of stenoses and waiting time for angioplasty are concerned. The stenotic vessels of the 7 patients who died or suffered infarctions had no collaterals. Thus coronary angioplasty should be performed immediately after the diagnostic angiogram. This leads to an increase in the success rate in patients with impending coronary occlusion. The spontaneous risk, however, of these patients in suffering sudden cardiac death or non-fatal infarction is low. On the other hand acute infarction and sudden death in the group of patients without detectable signs of impending occlusions can only be prevented by shortening the waiting time for angioplasty.

Adult↗
PubMed1984

[Frequency of recurrence following successful balloon dilatation of coronary artery stenoses].

In 333 (94%) out of 356 patients, who underwent successful TCA between October 1977 and June 1983, follow-up angiograms were performed. A total of 439 follow-up angiograms taken at 1-48 (on average 5.6) months after successful angioplasty were analysed. Restenosis rate was 12% if defined as remaining luminal widening of less than 20% compared to the situation before angioplasty. Its rate was 16% if defined as loss by at least 50% of the initial increase in luminal diameter. Restenosis rate was 17% if according to the international registry of the NHLBI defined as either loss by at least 50% of the initial increase in luminal diameter or as an increase in post-TCA-stenosis by at least 30%. When excluding those patients with restenosis who underwent repeat TCA and those with dilatation of an aortocoronary bypass stenosis the restenosis rate was reduced to 15.4%. In these two subgroups restenosis rate was 33% and 45%, respectively. Several factors may be responsible for the observed relatively low restenosis rate: Selection of patients Technique of TCA Medical treatment during and after TCA Reduction of risk factors, compliance of patients Unknown factors. Chronical medical treatment with high doses of acetylsalicylic acid, nitrates, and calcium blockers are considered most likely to be responsible for this result.

Angioplasty, Balloon↗