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Biomedical subjects

M Kaltenbach

Publications and source records attributed to M Kaltenbach.

At least 127 records · Page 7Linked to original sources
PubMed1989

Hemodynamic effects of nitroglycerin in an experimental model of acute aortic regurgitation.

Afterload reduction is an accepted therapeutic modality for the treatment of congestive heart failure caused by chronic aortic regurgitation. However, the role of vasodilator therapy in acute aortic incompetence has not been established. To investigate this, left ventricular volume overload was produced in 18 dogs by constructing a valved conduit from the descending thoracic aorta to the left ventricular apex. The time course of aortic, pulmonary and conduit flows was analyzed in eight control studies and established stability of the experimental model. In the remaining 10 dogs, intravenous nitroglycerin, titrated to reduce mean aortic blood pressure by 40%, and placebo (ethanol) were each infused for 20 min periods. Compared with placebo, nitroglycerin significantly reduced aortic flow (3,945 +/- 324 to 3,397 +/- 362 ml/min, p less than 0.01), regurgitant flow (1,304 +/- 131 to 764 +/- 90 ml/min, p less than 0.001), septal-lateral end-diastolic diameter (47.5 +/- 1.8 to 46.5 +/- 1.8 mm, p less than 0.001), left ventricular end-diastolic pressure (6.9 +/- 0.8 to 6.0 +/- 0.6 mm Hg, p less than 0.05), left ventricular stroke work (19.0 +/- 2.6 to 10.8 +/- 1.7 g-m/beat, p less than 0.001) and systemic vascular resistance (2,253 +/- 173 to 1,433 +/- 117 dyne-s/cm5, p less than 0.001). In contrast, pulmonary flow, left anterior descending coronary flow and subendocardial pH did not change during infusion of either nitroglycerin or placebo. These data indicate that by decreasing preload and afterload, and by preserving coronary flow and tissue pH, nitroglycerin effectively reduced ventricular and regurgitant volumes in the setting of acute volume overload.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

[Basic therapy of chronic heart failure with digitalis or diuretics?].

Sixteen patients in heart failure and sinus rhythm were, after a four-week treatment-free period, randomly assigned to receive, for four to six weeks, either a diuretic combination (hydrochlorothiazide + triamterene) or a digitalis glycoside. Subsequently the treatment was exchanged between the two groups. Without treatment nine patients were in stage II (New York Heart Association classification), seven in stage III. Pulmonary wedge pressure at rest was 27 +/- 14, on exercise 32 +/- 8 mm Hg, cardiac output 5.3 +/- 1.0 at rest and 7.8 +/- 2.3 l/min on exercise. Digitalis glycosides improved symptoms by one stage in three of 16 patients. All objective measures showed slight but not significant improvement. Diuretic treatment improved symptoms in five patients, while heart size and echocardiographically measured ventricular volume decreased slightly. Cardiac output decreased at rest, but not significantly, and on exercise not at all. Pulmonary arterial pressure (21 +/- 9 mm Hg), pulmonary wedge pressure (13 +/- 7 mm Hg) and pulmonary artery pressure on exercise (39 +/- 11 mm Hg) were significantly lower on diuretics than without treatment. The results support the primary use of diuretics in the treatment of chronic heart failure.

Aged↗
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

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

Low-speed rotational angioplasty in chronic peripheral artery occlusions: experience in 83 patients. Work in progress.

Between December 1986 and October 1988, 83 patients with chronic peripheral artery occlusions were treated with a new technique. In 56 patients, the superficial femoral artery was completely occluded; in 21 patients, the popliteal artery; and in six patients, the iliac artery. The length of occlusion ranged from 5 to 35 cm (mean, 12.5 cm). The duration, estimated by history, was 5-48 months (mean, 16.5 months). In seven patients, durations of 6-36 months were documented angiographically. A flexible, blunt, motor-driven rotating catheter was introduced through an 8-F sheath, and rotational angioplasty was performed at low speed (up to 200 rpm). In 49 of 60 (82%) patients in whom this new technique was used as the primary intervention, the occlusions were successfully reopened. In 23 patients in whom conventional methods had failed more than 4 weeks earlier, the success rate for rotational angioplasty was 67% (12 of 18 patients); when the time interval was less than 4 weeks, only one of five patients was treated successfully. In none of the 83 patients did a perforation occur. This new technique can reopen chronic artery occlusions with a high degree of success and without the danger of vessel-wall perforation, even after failure of conventional techniques.

Adult↗
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

[Rotation angioplasty--clinical experiences in 83 patients with chronic arterial vascular occlusion].

Chronic, total vascular occlusion represents the limit for use of balloon dilatation. Occlusions of the superficial femoral artery and popliteal artery of more than 10 cm in length have a low recanalization rate of 50 to 60% with conventional angioplasty. In iliac artery occlusions, in addition to a high rate of complications, the recanalization rate is only about 30 to 40%. Starting in 1984, we developed a slowly rotating (100 to 200 r.p.m.), electrically-driven, flexible catheter with a blunt tip, inside lumen and outer diameter of 2.2 mm for the purpose of recanalization (Figure 1). The theoretical basis was that such a catheter would seek the soft occluding thrombus as the path of least resistance. Since 1986, the procedure has been carried out in 56 patients with occlusion of the superficial femoral artery, 21 with occlusion of the popliteal artery and six with occlusion of the iliac artery. The duration of occlusion ranged between five and 48 months and the length of the occlusions between 5 and 35 cm (mean 12.5 cm); the patients were in Fontaine stage II and IV, the ankle arm-index ranged between 0 and 0.86 (mean 0,51). After antegrade or retrograde puncture of the common femoral artery and intra-arterial injection of 5,000 units of heparin, the rotation catheter was advanced through an 8F sheath through the occlusion by means of slow rotation (Figure 2). After contrast medium injection to document the intraluminal position of the catheter and the catheter exchange over a 0.35'' wire, the channel created was dilated.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
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

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

[Diastolic ventricular function in hypertrophic, obstructive and non-obstructive cardiomyopathy--effect of gallopamil].

Left ventricular function was investigated by radionuclide ventriculography in 13 patients (11 male, two female) with hypertrophic cardiomyopathy, aged from 22-57 years (mean 45.5 years) at rest and during exercise. Ten patients had hypertrophic obstructive cardiomyopathy with maximal left ventricular outflow tract gradients of 64-290 mmHg (mean 147 mmHg). Left ventricular enddiastolic pressure of all patients ranged from 8-35 mmHg (mean 21 mmHg). Radionuclide ventriculography was performed without therapy, after acute application of a single oral dose of gallopamil (50 mg), and after longterm treatment for 3 weeks (50 mg tid). Ejection fraction at rest after single dose increased from 69.2% to 72.9% (p less than 0.02), peak ejection rate (PER) increased from 333.5 to 362.0/s (p less than 0.01) and peak filling rate (PFR) from 284.5 to 316.5/s (p less than 0.02). Under exercise single dose as well as longterm treatment led to a slight but significant shift in the ratio of PFR/PER (from 1.02 to 1.12 after single dose [p less than 0.04], and to 1.18 with longterm treatment [p less than 0.03]). There was no correlation between the individual response to gallopamil treatment and histopathological parameters such as hypertrophy or fibrosis. These data demonstrate that gallopamil in patients with hypertrophic cardiomyopathy leads to an improvement mainly in left ventricular diastolic function which appears to be most effective under exercise.

Adult↗
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↗