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Biomedical subjects

M Klepzig

Publications and source records attributed to M Klepzig.

17 recordsLinked to original sources
PubMed1989

Peripheral percutaneous transluminal laser angioplasty in humans: in vitro investigations and clinical results with a novel laser catheter system.

Percutaneous transluminal laser angioplasty has become an accepted method of treatment of peripheral arterial occlusive disease. To minimize the risk of arterial wall perforation during laser angioplasty, a novel laser catheter system was developed. In 113 obliterated postmortem human arteries the perforation rate was 0.9%. The mean degree of stenosis was reduced from 89 +/- 9% before, to 53 +/- 11% after laser irradiation. Clinical Nd:YAG laser angioplasty was performed in 19 patients suffering from peripheral arterial occlusive disease. The Fontaine stage improved in 16 patients; in no case did it deteriorate. The mean degree of stenosis was reduced by laser angioplasty from 91 +/- 12% to 31 +/- 19%. A further reduction down to 13 +/- 18% was achieved by subsequent percutaneous transluminal balloon angioplasty. The systolic Doppler ankle-arm pressure gradient was improved from 0.58 +/- 0.26 to 0.89 +/- 0.25. In 7 patients microembolisms were detectable on the final angiogram. There was no acute reocclusion and no perforation. Within a follow-up period of 12 months, four restenoses were diagnosed by digital subtraction angiography. On average, the Doppler index was 0.75 +/- 0.32.

Angioplasty, Balloon↗
PubMed1988

[Percutaneous peripheral laser angioplasty: initial clinical results].

Laser angioplasty has developed as a new method for the treatment of peripheral arterial occlusive disease. In 19 patients with high grade stenoses or obstructions of the superficial femoral, popliteal or posterior tibial arteries (Fontaine stage IIa-IV) percutaneous transluminal laser angioplasty was performed using a novel laser catheter system. The laser catheter itself is made of polyethylene. Its distal tip is formed ovally and marked X-ray densely. A silica fiber (core diameter 0.6 mm) for delivering the laser energy is inserted into the laser catheter. Through a sheath with hemostatic valve, laser catheter and silica fiber are introduced into the artery and then advanced to the stenosis over a guide wire. During laser angioplasty, laser catheter and silica fiber are rotated around the guide wire. We use a cw-Nd: YAG laser with a wavelength of 1064 nm. The mean degree of stenosis decreased from 92 +/- 12% before to 31 +/- 19% after laser angioplasty. By conventional balloon angioplasty a further reduction of the degree of stenosis down to 15 +/- 20% was achieved. The mean systolic Doppler ankle-arm pressure ratio improved from 0.56 +/- 0.25 before laser angioplasty to 0.89 +/- 0.24 after combined laser and balloon angioplasty. In seven patients, clinically non-significant distal embolization occurred. In no patient there was a perforation of the arterial wall. Up to now, digital subtraction angiography 3 months after laser angioplasty has been performed in five patients and showed patency of all lesions. The mean systolic Doppler ankle-arm pressure ratio was 0.84 +/- 0.20.

Aged↗
PubMed1988

[Percutaneous transluminal laser angioplasty in peripheral arterial occlusive disease--development of a new laser catheter system].

Percutaneous laser angioplasty in arterial occlusive disease has lately been performed clinically for the first time. Perforation of the arterial wall and formation of aneurysms are serious risks. Two novel laser catheters for laser angioplasty with minimized perforation risk are presented. Catheter I (5F) and II (6.3F) are designed in the same manner. The distal tip of these catheters is ovally formed and marked by a small X-ray dense metal ring. The silica fiber has a core diameter of 400 micron (I) respectively 600 micron (II). Its tip is also marked X-ray densely and therefore the position of the fiber tip can be controlled exactly during laser angioplasty. Using a guide wire and applicating short laser pulses the perforation risk can be minimized. In a total of 132 atherosclerotic stenosed or obstructed human arteries laser angioplasty was performed in vitro using a Nd:YAG laser. There were two perforations (1.5%). The degree of stenosis was reduced from 87 (90)% to 54 (52)%. Using the 600-micron-fiber (catheter II) the velocity of laser angioplasty was increased 2.5 times compared to laser angioplasty using the 400-micron-fiber.

Angioplasty, Balloon↗
PubMed1987

Regression of cardiac hypertrophy: experimental and clinical results.

Since left ventricular hypertrophy is considered to be a precursor of later hypertensive heart failure, a treatment that can prevent or even reverse myocardial hypertrophy is a highly desirable goal. In order to evaluate which type of antihypertensive treatment is able to induce regression of hypertensive hypertrophy, experimental and clinical studies were performed. Experimental studies were performed in spontaneously hypertensive rats (SHRs). Left ventricular hypertrophy and pumping function were studied after antihypertensive treatment with a beta-receptor blocker (metoprolol), an arteriolar vasodilator (hydralazine), and a calcium channel blocker (nifedipine) had been instituted for a period of 20-40 weeks. Patients with hemodynamically compensated hypertensive heart disease were treated with a calcium channel blocker (nifedipine), an angiotensin-converting enzyme (ACE) inhibitor (enalapril), an antisympathetic agent (clonidine), and prazosin. Comparing the amount of blood pressure reduction with the extent of hypertrophy reversal, nifedipine, prazosin, and enalapril were equipotent, whereas clonidine was most efficient in this respect. Muscle mass was overproportionally reduced in relation to blood pressure reduction following treatment with clonidine. It is likely that this was caused by lowered catecholamine levels secondary to clonidine therapy. Left ventricular pumping function was enhanced as a result of a reduction in left ventricular afterload, whereas myocardial contractility was found to be unchanged.

Animals↗
PubMed1987

Media hypertrophy in hypertensive coronary resistance vessels.

Coronary reserve is reduced in human hypertensive hypertrophy and in the model of spontaneously hypertensive rats (SHRs). In isolated coronary resistance vessels, the role of structural and functional changes was evaluated. Furthermore, the effect of long-term antihypertensive therapy was also studied. At the age of 20 weeks, SHR and Wistar-Kyoto (WKY) rats were examined. Distal segments of the left anterior descending coronary artery were dissected and mounted on a myograph developed by Mulvany and Halpern. After recording of radius-wall tension curves, the vessels were set up to a wall tension equal to two-thirds of the systolic blood pressure. In SHRs, the vessel diameters were reduced. After equilibration with Ringer's solution, vessel dilatation was decreased in calcium-free solution (10 +/- 3 vs. 34 +/- 7%, p less than 0.05), but contraction increased after 123 mM of potassium stimulation (78 +/- 19 vs. 33 +/- 9%). There was no difference in calcium sensitivity during methoxamine or potassium activation. In the coronary resistance vessels of SHRs, electron microscopy revealed media hypertrophy (15.6 +/- 2.9 vs. 9.5 +/- 2.1 microns, p less than 0.05) and media hyperplasia (4.5 +/- 3 vs. 3.7 +/- 6 muscle layers, p less than 0.05). Media hypertrophy and a decrease in the vasodilatating capacity of resistance vessels contribute to the reduction of coronary reserve in hypertensive hypertrophy. The minimal coronary vascular resistance, a parameter of the vasodilatating capacity, was significantly increased in SHRs. Antihypertensive therapy with metoprolol and hydralazine or nifedipine resulted in an improvement of coronary reserve.

Animals↗
PubMed1985

[Amrinone in acute and long-term therapy].

The purpose of this study was to evaluate acute and chronic therapeutic effects of the positive inotropic vasodilating agent amrinone. 50 patients with cardiomyopathy or coronary artery disease and left heart failure participated in the study. Swan-Ganz catheterisation was used in 15 patients; following injection of 1.5 mg/kg amrinone, the mean pulmonary pressure decreased by 26%, the wedge pressure by 27%. Cardiac index rose by 18% (p less than 0.01). 35 patients were examined in the oral study, the avg. dose being 300 mg/day. After 2 and 12 weeks of therapy, exercise tolerance increased by 22% and 13% respectively (p less than 0.05). Cardiac output after maximal workload as determined by equilibrium radionuclide ventriculography increased by 27% and 30% respectively (p less than 0.05). 34 side effects occurred in 23 of 35 patients: nausea, orthostasis, angina pectoris, tachyarrhythmia, hepatotoxicity, thrombocytopenia, hyperuricemia and brown coloring of finger-nails. From the hemodynamic point of view amrinone is intravenously and orally effective. Careful selection of patients and frequent examinations are however necessary.

Administration, Oral↗
PubMed1984

[Therapy of the hypertensive crisis with urapidil. Various effects on patients with or without coronary disease].

The effect of urapidil on various hemodynamic and echocardiographic parameters has been investigated in 36 patients with hypertensive emergencies (14 patients with coronary artery disease, 22 patients without coronary artery disease). During treatment with urapidil, blood pressure decreased in both groups by 35%, the heart rate decreased slightly (3-8%). The mean pulmonary artery pressure decreased by 45% (coronary patients) respectively 36% (non-coronary patients), the pulmonary capillary wedge pressure by 59% (coronary patients) resp. 48% (non-coronary patients). Cardiac output increased in both groups by about 20%. In the echocardiogram, both groups showed decreases in the diameters of left atrium and left ventricle, and an increase in the fractional shortening of the left ventricle. Patients with coronary artery disease required less urapidil than non-coronary patients.

Acute Disease↗
PubMed1984

[Quantitative resting radionuclide-ventriculography for multifactorial analysis of left ventricular function].

Results from 388 patients, examined with quantitative equilibrium radionuclide ventriculography (qERNV) at rest, were stored in a data bank system and evaluated statistically. The value of time and velocity parameters [ejection time (ET), filling time (FT), time ES to peak filling rate (TpFR), mean (mER) and peak (pER) ejection rate, peak filling rate (pFR)] were evaluated in patients with coronary heart disease (CHD, with and without history of earlier myocardial infarction) or with cardiomyopathy (CMP). Significant (p less than 0.025) changes vs. normal in CHD I/II were obtained from pER, pFR, ET, in CHD III from gEF, EDV, mER, pER, pFR, in CHD IV from gEF, EDV, mER, pER, pFR, in patients with infarction or with CMP from gEF, EDV, mER, pER, pFR, ET and TpFR. Resting qERNV revealed a sensitivity in diagnosing a CHD (stages I-III) by mER of 30-59%, by pER of 40-65%, by pFR of 48-60% and by ET of 58-61%, which was higher than the sensitivity of gEF (19-56%).

Cardiac Output↗
PubMed1984

[Right ventricular hemodynamics and lung function following amrinone injection].

UNLABELLED: Amrinone is a positive inotropic agent which has been widely used for treatment of left heart failure. As this drug has a relaxing effect on smooth muscle cells, we considered that hemodynamics and ventilatory mechanics could be simultaneously improved in patients with right heart failure caused by obstructive lung disease. Swan-Ganz catheters were used in 11 patients. Following injection of 1.5 mg/kg Amrinone, cardiac output increased from 6.1 to 6.9 l/min (p less than 0.05). Stroke volume showed only a slight increase; pulmonary vascular resistance was reduced from 407 to 308 dynes . s . cm-5 (p less than 0.01). Body plethysmographic examination revealed a decrease of specific airway resistance from 33 to 24 cm H2O . s (p less than 0.01). CONCLUSION: In patients with right heart failure due to obstructive lung disease Amrinone application can result in an improvement in both hemodynamics and ventilatory mechanics.

Airway Resistance↗
PubMed1983

[Myocardial 201-thallium uptake after hydralazine in coronary disease].

UNLABELLED: Following injection of hydralazine, a benign coronary-artery-dilating drug, myocardial blood flow increased by 25%. Myocardial 201-thallium uptake at rest and after intravenous injection of 12 mg hydralazine was quantitatively investigated in 28 patients. In patients with essential hypertension or coronary artery stenoses of up to 90%, myocardial 201-thallium uptake increased by 19%-30% in nonischemic areas. In 9 of 14 patients with regional imaging defects, thallium uptake also increased in these ischemic areas; 4 of these patients had asynergies in the area of imaging defects. In 3 patients with a complete obstruction of a major branch of a coronary artery perfusion defects developed following hydralazine application. CONCLUSION: An increased 201-thallium uptake in an ischemic area indicates reperfusion; this could be helpful for deciding whether coronary surgery should be performed or not.

Coronary Circulation↗