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Biomedical subjects

G Kober

Publications and source records attributed to G Kober.

At least 91 records · Page 5Linked to original sources
PubMed1990

[Coronary angioplasty--can the risk of recurrence be predicted on the day of surgery? A prospective study].

Data from a retrospective study defining seven parameters of increased risk of restenosis after successful transluminal coronary angioplasty (high-grade stenoses, long stenoses, eccentric stenoses, use of high pressure, extended time of balloon inflation, stenoses in obese patients, stenoses in patients without a history of smoking) were fed into a computer. A discriminant analysis was made and an algorithm for prediction of restenosis was defined. The validity of prediction was prospectively tested in 101 patients. In 80/101 (79.2%) prediction was possible; in 21/101 (20.8%) it was not possible. In 15/80 patients (18.8%) the prediction was: "restenosis probable"; in 65/80 patients (81.2%): "restenosis not probable". After 4.4 months 93/101 patients (92.1%) had an angiographic follow-up. The prediction "restenosis" proved to be correct in 13/15 patients (86.7%), and the prediction "no restenosis" was correct in 56/65 patients (86.2%). It is concluded that in the majority of patients the risk of restenosis can be predicted immediately after the intervention.

Adult↗
PubMed1990

[Long-term clinical follow-up after coronary dilatation].

To determine the long-term clinical course after percutaneous transluminal coronary angioplasty (PTCA), 841 patients, 615 with successful PTCA and 226 without, were restudied by questionnaire 2-9 years after the intervention. After successful PTCA a lasting symptomatic improvement was seen in 78% of patients vs 55% of patients without successful PTCA (p less than 0.0001). The probability of myocardial infarction 8 years after successful PTCA was 6% vs 24% after unsuccessful PTCA (p less than 0.0005). The 8-year survival probability (non-cardiac deaths excluded) was 95.7% in patients with demonstrable PTCA success, and 92.0% in patients without (p less than 0.05). Similar significant differences in favor of patients with successful PTCA were seen in the long-term prognosis of patients with single-vessel disease (n = 580). It is concluded that a long-term improvement of the cardiac prognosis by successful PTCA is probable.

Angioplasty, Balloon, Coronary↗
PubMed1989

[Ischemic reaction in a young woman without coronary sclerosis: Bland-White-Garland syndrome].

A 39-year-old woman, with known mild mitral regurgitation, developed progressively more severe symptoms of angina, associated with an ischaemia response in the exercise electrocardiogram. Angiocardiography demonstrated an anomalous origin of the left coronary artery from the pulmonary artery (Bland-White-Garland syndrome). At operation an aortocoronary venous bypass graft was constructed; the patient has been without symptoms since and the exercise ECG is normal. As demonstrated by angiography, the previously marked dilatation of the right coronary artery had largely regressed and previously present collaterals to the left coronary artery were no longer visualized three months after operation. The described coronary artery anomaly, although rare, should be considered in a young patient with reproducible coronary artery ischaemia.

Adult↗
PubMed1989

[Catheter valvuloplasty in mitral valve stenosis].

Balloon dilatation of the mitral valve was performed, trans-septum via the femoral vein or retrogradely via the femoral artery, in 20 patients, aged 31-65 years, with post-rheumatic mitral stenosis. Haemodynamically insignificant mitral regurgitation occurred in two patients. In one patient a permanent atrial septal defect was produced by the transseptal puncture. In a fourth patient severe mitral regurgitation occurred which required operation. There were no other serious complications. No dilatation was possible in three patients for technical reasons. Successful dilatation was achieved in 16 of the 20 patients. The end-diastolic transvalvular pressure gradient was reduced from 12 +/- 5 to 4 +/- 3 mm Hg. At follow-up, after 3-6 months (12 patients) or after 1-1.5 years (5 patients), in one instant after a second dilatation, a lasting good result was confirmed, the mean end-diastolic gradient being 4 +/- 3 mm Hg.

Adult↗
PubMed1989

Hemodynamic and antianginal effects during rest and exercise of intravenous isradipine, a new dihydropyridine calcium antagonist.

In an open randomized study, hemodynamic and antianginal effects of nifedipine and the new dihydropyridine derivative isradipine were compared in patients with stable, angiographically confirmed coronary heart disease. Right heart hemodynamics, systemic arterial blood pressure, ECG, and drug plasma concentrations were measured before medication at rest and exercise, after infusions of increasing doses at rest, and again after treatment at rest and exercise. A linear relationship between serum concentrations and cumulated dosages was obtained for both drugs. At rest, both drugs significantly increased cardiac output and heart rate. The reduction of arterial blood pressure was significantly greater after isradipine (systolic from 148 +/- 3 to 104 +/- 3 mmHg; diastolic from 90 +/- 4 to 58 +/- 2 mmHg) than after nifedipine (systolic 149 +/- 6 to 125 +/- 4 mmHg; diastolic 92 +/- 4 to 76 +/- 3 mmHg). The minimal effective plasma level of isradipine regarding blood pressure reduction was estimated at 5 ng/ml (nifedipine: 10-25 ng/ml). During exercise both medications significantly reduced mean pulmonary artery pressure (isradipine: 40 +/- 3 to 20 +/- 1 mmHg, nifedipine: 37 +/- 4 to 22 +/- 1 mmHg), pulmonary artery wedge pressure (isradipine: 23 +/- 3 to 10 +/- 1 mmHg, nifedipine 24 +/- 3 to 14 +/- 1 mmHg), and diastolic arterial pressure (isradipine: 103 +/- 3 to 73 +/- 4 mmHg, nifedipine: 99 +/- 3 to 91 +/- 2 mmHg), whereas systolic pressure was reduced by only isradipine (189 +/- 4 to 147 +/- 5 mmHg). Neither medication significantly changed electrocardiographic ST depression during exercise.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1989

Restenosis is a common feature of the angiographic follow-up after balloon valvoplasty of calcified aortic stenoses.

Balloon dilatation of calcified aortic stenosis was attempted in 12 patients, 6 men and 6 women, aged 38-82 years. Two patients underwent emergency surgery because of myocardial injury or pericardial tamponade. One patient with severe depressed left ventricular function in whom the procedure was attempted in cardiogenic shock died during the procedure. One patient experienced severe aortic insufficiency after dilatation. The remaining pressure gradient was higher than 50 mm Hg in another patient. Seven dilatations were considered to be successful with a remaining pressure gradient below 50 mm Hg and a mean gradient reduction of 53 mm Hg. In one of these 7 patients, who suffered from severe heart failure, valvoplasty had been carried out to make aortic valve replacement possible. The operation was performed 2 weeks later without complications. Five of 6 patients treated medically after successful valvoplasty had restenosis within 3 to 12 months. One of them exhibited a good result at 3 months but severe restenosis after one year. It is concluded that balloon valvoplasty of calcified aortic stenosis cannot be considered an alternative to surgery. If, however, left ventricular function improves after successful valvoplasty, valve replacement will then carry less risk.

Adult↗
PubMed1989

Coronary stenosis dilation by low dose intravenous nitroglycerin.

In a randomized double-blind study, 40 patients with coronary heart disease received either 0.025 mg nitroglycerin or placebo intravenously. Before and 2-3 min after injection, the aortic and left ventricular pressures were recorded and coronary angiography was performed. Mean heart rate, systolic and diastolic aortic pressure, left ventricular filling pressure and the pre- and poststenotic coronary artery diameters, as well as the diameters of representative distal coronary artery segments showed no significant changes. Coronary artery stenosis diameters remained unchanged after placebo (1.01 +/- 0.5 to 1.13 +/- 0.49 mm; n.s.) but increased significantly after nitroglycerin from 1.15 +/- 0.68 to 1.32 +/- 0.73 mm (P less than 0.01). Since it has been demonstrated, on the other hand, that the same dose of nitroglycerin reveals antianginal activity, it can be hypothesized from these results that dilatation of coronary stenoses plays an important role in the antianginal action of nitroglycerin. Strong haemodynamic effects do not appear to be a prerequisite of the beneficial effects of nitroglycerin.

Adult↗
PubMed1989

Recognition of restenosis: can patients be defined in whom the exercise-ECG result makes angiographic restudy unnecessary?

The value of exercise ECG in predicting the occurrence of restenosis after successful transluminal coronary angioplasty (PTCA) was investigated in 398 patients with exercise tests of comparable workload before, immediately after and within 6 months after PTCA. In patients with normalized exercise ECG (n = 166) restenosis was observed in 16.3% and indication for repeat PTCA was present in 6.6%. RePTCA was recommended in only 3.2% of patients if the exercise test was still normal at restudy and if the patients were free of anginal symptoms. In patients with a renewed ST-segment depression (n = 77) the rate of restenosis was 67.5% and the indication for rePTCA was present in 52%. In patients without changes in the exercise tests before and after PTCA and at restudy (n = 155) restenosis was seen in 25.8% and rePTCA was recommended in 14.2%. It is concluded that from the clinical point of view, in patients with improved exercise ECG at restudy, especially if they are free of angina, there is no need for a re-angiogram because indications for rePTCA are very rare.

Angioplasty, Balloon, Coronary↗
PubMed1989

Results of repeat angiography up to eight years following percutaneous transluminal angioplasty.

Percutaneous transluminal coronary angioplasty (PTCA) has become a widely accepted procedure that provides acute and medium-term relief of anginal symptoms and myocardial ischaemia. The acute success rate has risen from about 50% in the early days to approximately 90% in recent years. Serial repeat angiograms obtained in different patient groups have shown a 20% incidence of angiographically defined restenosis in patients who had been successfully treated initially. Despite the restenosis, many of these patients were symptomatically improved since the lesions shown at follow-up angiography were often less severe than those that had existed prior to original PTCA. These figures suggest that a success rate of 80% at 1 year should now be a realistic expectation, especially when patients with repeat PTCA are included. None of the 87 patients re-angiographed between 2 and 8 years after successful PTCA developed restenosis after the first year of treatment. However, new stenoses of 50% or more were found in other vessel segments, in both symptomatic and asymptomatic patients, at a rate of about 7% per year.

Angioplasty, Balloon, Coronary↗
PubMed1989

Long-term results of percutaneous pulmonary valvuloplasty in adults.

We performed percutaneous balloon valvuloplasty of the pulmonary valve in 24 patients (aged 17 to 72 years) and in two juvenile patients. There were no major complications. In almost all the patients the procedure resulted in a successful pressure gradient reduction from a mean of 92 +/- 36 mmHg to 43 +/- 19 mmHg (P less than 0.01). In seven patients there was a residual pressure gradient greater than 50 mmHg which, however, decreased in all patients within the following 3-12 months due to a decrease in subvalvular muscular hypertrophy (from a mean of 70 to 35 mmHg). No restenosis was observed. Only one patient, who had calcified valve leaflets, developed pulmonary insufficiency and this was of only minor haemodynamic importance. Balloon dilatation of the pulmonary valve can be considered a technique with a high success rate and low complication rate even in the elderly. Good long-term results support this approach as the first choice in the treatment of pulmonary valve stenosis.

Adolescent↗
PubMed1989

Can the progression of coronary sclerosis be influenced by calcium antagonists?

The influence of chronic verapamil treatment on the development of human coronary sclerosis was retrospectively investigated in 26 patients; 17 nontreated patients served as controls. The same issue has been dealt with prospectively in a second and still ongoing, double-blind, placebo-controlled study in 444 patients selected after bypass surgery. The retrospective study on patients treated with verapamil revealed a slower development of the overall coronary disease with a slower progression in individual stenoses, more pronounced regression, especially with high-grade stenoses, and less frequent occurrence of new significant stenoses. The question is still open as to whether these effects can be confirmed by the prospective study, the data of which will be available at the end of January 1991, at the earliest, on completion of a 3-year follow-up.

Angiocardiography↗
PubMed1989

[Long-term therapy following myocardial infarct with isosorbide dinitrate in a low and high dose].

The favorable response to nitrates in the case of coronary heart diseases is based on both reduction in left ventricular pre- and afterload and improvement in coronary flow. These effects were studied in the setting of a long-term ISDN therapy with reference to the prognosis of patients after myocardial infarction. Following acute treatment in the respective hospitals, 608 patients with myocardial infarctions were allocated to two double-blind treatment groups with different ISDN dosage levels (group 1 = 5 x 2.5 mg i.d.; group 2 = 5 x 40 mg i.d.) and followed up over a period of 2 years. No differences were found with regard to the end points sudden cardiac death, reinfraction, and indication for revascularization. There was, however, a more frequent additional administration of calciumantagonists to patients of the low-dose group (p less than 0.05), a more frequent drop-out due to the lack of beneficial therapeutic results, and a more exceptional drop-out due to side effects in patients treated with low doses of ISDN (n.s.). The absence of any significant difference with regard to the end points might be attributed to; 1) a loss of potency of high-dose ISDN and simultaneous ineffectiveness of low-dose ISDN; 2) an efficacy of low doses; 3) an absence of actual influence on the target parameters, and 4) an inadequate follow-up time period.

Coronary Circulation↗
PubMed1989

[Anti-angina and coronary dilating effect of low-dose nitroglycerin].

Fourteen patients with typical exercise-induced angina and ST-segment depression received 0.025 mg nitroglycerin intravenously or placebo directly before exercise testing in a double-blind cross-over study. The sum of ST-segment depressions during stress and recovery was 12.8 +/- 4.8 mm after placebo and 8.9 +/- 4.6 mm after nitroglycerin (p less than 0.001). The symptom-free exercise time increased from 3.1 +/- 1.4 to 4.3 +/- 1.9 min (p less than 0.1), whereas severity of angina during exercise decreased significantly (p less than 0.05) after nitroglycerin. There was no influence on either heart rate or blood pressure. In a second randomized double-blind study, 40 patients with coronary heart disease received either 0.025 mg nitroglycerin or placebo intravenously. Before and 2 min after injection the aortic and left ventricular pressures were recorded and coronary angiography was performed. Mean heart rate, blood pressure, left ventricular filling pressure and pre- and poststenotic coronary artery diameter, as well as the diameters of representative distal coronary artery segments showed no significant changes. Coronary artery stenosis diameters remained unchanged after placebo, but increased significantly after nitroglycerin from 1.15 +/- 0.68 to 1.32 +/- 0.73 mm (p less than 0.01). It can be hypothesized from these results that dilatation of coronary stenosis plays an important role in the antianginal action of nitroglycerin. Coronary artery stenoses seem to be more sensitive to nitroglycerin than are other vessel segments.

Angina Pectoris↗
PubMed1989

[Long-term effect of organic nitrates in angina pectoris: dependence on the form of administration and mode of stress].

ISDN (standard release formulation) 40 mg administered 6 times daily (= 240 mg) remained effective during a 4-week treatment of patients with stable angina in terms of decreasing anginal attacks and reducing ischemic ST segment depression at stress testing in the upright position (step climbing test). The sustained antianginal activity is explained by fluctuating plasma levels, provided by rapid drug release from the standard formulation, short administration intervals and an 7-hour-night pause. When comparing acute and chronic antianginal activity of ISDN (40 mg) administered 4 times daily with regard to the type of stress testing it became evident that a marked attenuation of antiischemic activity (-35%; p less than 0.01) occurred in the supine (bicycle ergometry) but not in the upright (step climbing test) position. The most probable explanation for the significant attenuation of efficacy in the supine position is marked blood redistribution into central compartments with increase of cardiac filling pressures during chronic therapy. Rapid development of tolerance both to the hemodynamic and antiischemic effects of glycerol trinitrate within 24 hours could be shown during intravenous administration (3 mg/h) in patients with stable angina. It is concluded that the antiischemic effects of oral ISDN (standard release formulation) administered 4-6 times daily is preserved during long-term therapy due to fluctuating plasma levels. Nitrate therapy providing constant doses over time (e.g. I.V. nitroglycerin) leads to a rapid attenuation of efficacy most probably due to counter regulatory mechanisms.

Administration, Oral↗
PubMed1989

[Isolated human venous segments as a model for the study of problems of nitrate tolerance].

Concentration-dependent relaxation (6-70%) of segments of human saphenous veins under isometric conditions could be demonstrated with cumulative concentrations of isosorbide dinitrate (ISDN) and Glycerol trinitrate GTN (10(-9)-10(-5) M). Vein segments were obtained during coronary by-pass surgery. Nitrate (GTN)-induced relaxation was accompanied by a 2- to 3-fold increase of cyclic GMP content in the vessel walls. However, no change of concentrations in the vessel walls could be determined for the metabolites of prostaglandines: (PG E2, PG F2 alpha, TX B2, 6-keto-PGF1 alpha). Pretreatment of patients with 40 mg ISDN (standard release formulation) 4 times daily for 1 week prior to surgery with the last dose 1 hour before harvesting the vein segments did not influence relaxation. by ISDN. Immersion of vein segments for 1 hour in buffer solution containing 10(-6) M ISDN (= therapeutic concentration) prior to relaxation with cumulative concentrations of ISDN did not influence relaxation either. Induction of in vitro tolerance required ISDN concentrations which exceeded the range achieved under therapeutic conditions: 4.4 x 10(-4) M. This in vitro tolerance could be widely reversed by 10 mM N-Acetylcysteine (NAC) suggesting involvement of sulfhydril (SH) groups. Since tolerance in this experimental model was not seen under concentrations achieved in patients it seems likely that clinical tolerance is caused by activation of counterregulatory forces.

Acetylcysteine↗
PubMed1989

Coronary arteriography with iotrolan 280, a blood-isotonic, nonionic, dimeric contrast medium: preliminary clinical results.

The effects of coronary arteriography with ionic, monomeric diatrizoate (iodine content, 370 mg/ml; osmolality, 2.10 Osm/kg) and nonionic, dimeric iotrolan (iodine content, 280 mg/ml; osmolality, 0.27 Osm/kg) were intraindividually compared in five patients with coronary heart disease. According to an open protocol, both contrast media were injected into the left (LCA) and right coronary arteries (RCA), 8 ml and 5 ml, respectively. Before, during, and 60 seconds after each injection, electrocardiograms (ECG) were recorded and heart rate and aortic pressure were measured. Whereas diatrizoate markedly decreased heart rate (LCA, -36%; RCA, -20%) and aortic pressure (LCA, -26%; RCA, -16%), iotrolan administration kept heart rate virtually unchanged (+/- 1%) and only slightly increased aortic pressure (LCA, 5%, RCA, 8%). After iotrolan injection ECG changes (axis shift of QRS and T waves) were still demonstrable, yet the effects of diatrizoate proved to be more significant (prolongation of QRS and QT intervals as well as shifts of QRS and T axis). The opacification of the coronary arteries was always more pronounced after diatrizoate due to its higher iodine content, but the contrast produced by iotrolan usually was satisfactory. No side effects were observed during the study. Thus, this isosmotic contrast medium prevents bradycardia and hypotension during coronary arteriography. The lower iodine content, however, leads to poorer contrast compared with conventional contrast media.

Blood Pressure↗
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↗