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Biomedical subjects

N Reifart

Publications and source records attributed to N Reifart.

At least 55 records · Page 3Linked to original sources
PubMed1990

[Treatment of coronary heart disease in the aged. When balloon dilatation, when surgery?].

Data from 3029 consecutive patients (2474 men, 555 women, mean age 59 [20-88] years) in whom coronary heart disease had been diagnosed by coronary angiography were studied with the object of identifying those patients in the older age group who are suitable for treatment by balloon angioplasty. There were 884 patients with a mean age of 70 (65-88) years, and 2145 patients with a mean age of 54 (20-64) years. Single vessel disease was less common in older patients (30% vs 44%; P less than 0.001), double vessel disease was equally common in both groups (28% vs 30%) and triple vessel disease was commoner in the elderly group (42% vs 26%; P less than 0.001). For elderly patients with single vessel disease conservative treatment was chosen in 50%, angioplasty in 49% and operative treatment in only 1%. Of elderly patients with involvement of two arteries, 44% were treated conservatively, 40% by angioplasty and 16% surgically. Of elderly patients with triple artery disease, 23% were treated conservatively, 8% by angioplasty and 69% operatively. This pattern was similar to that among younger patients. The success rate and the incidence of complications after percutaneous transluminal coronary angioplasty were similar in both age groups. In elderly patients with disease of only one or two coronary arteries the prospects of success and the risks are comparable to those in younger patients, but patients with triple artery disease often need bypass surgery.

Adult↗
PubMed1990

[Echocardiographic functional parameters of the left ventricle as a prognostic indicator in coronary heart disease].

The value of two-dimensional cross-sectional echocardiography for the estimation of the left ventricular function had been investigated in 241 consecutive patients with suspected coronary artery disease (CAD). The day before left heart catheterization the left ventricular volumes (EDV, ESV) as well as the global left ventricular ejection fraction (EF) were calculated from the RAO-equivalent in the 2D-echo and in addition the classification of the EF was visually performed from different cross-sections. The coronary angiography showed in 208/241 patients hemodynamically effective stenoses (lumen restriction greater than 50%). For 192/208 patients there were diagnostically usable 2D-echograms as well as clinical data over an observation period of 3 years and 7 months. The 2D-echo correspond quite well to the levocardiography for the calculation of the EDV with r = 0.75, with r = 0.85 for the ESV, and with r = 0.80 for the EF. The mere visual evaluation of the EF out of the 2D-echo agreed well in 84% of the cases to the quantitative determination. During the observation period 18/192 patients died; 17/18 of these patients of cardial causes. Out of the patients with normal EF in the 2D-echo only 3.5% died, with slightly reduced EF 10% died. With highly reduced EF mortality was with 40% significantly increased (p less than 0.001). Thus in patients with CAD unfavourable long-time prognosis may be quickly recognized by their markedly reduced left ventricular function in the 2D-echocardiogram, which shows favourable correspondence to invasive data.

Adult↗
PubMed1990

Surgical correction of a severely obstructed pulmonary artery bifurcation in Takayasu's arteritis.

A young male patient (NYHA III) presented with a severe pulmonary artery bifurcation stenosis of unknown origin. He underwent successful radical resection and endarterectomy of abundant endoluminal and perivascular inflammatory tissue. Surgery was performed with extracorporeal circulation (ECC) without transection of the aorta and the pulmonary artery bifurcation was enlarged with a patch. Right ventricular to peripheral pulmonary artery pressure gradient fell from 80 mmHg preoperatively to 25 mmHg 18 months postoperatively. The patient is fully rehabilitated and working (NYHA I). Histological examination confirmed Takayasu's arteritis as the underlying disease and medium-term follow-up angiography showed an almost normal pulmonary artery bifurcation. We conclude that the radical surgical approach is a valuable palliation in this disease.

Adult↗
PubMed1990

Experimental balloon valvuloplasty of fibrotic and calcific mitral valves.

This study evaluated the mechanism of valvular area expansion during single- and double-balloon valvuloplasty in fibrotic and calcific mitral valves. Special interest was focused on the morphological features of the valves treated. Mitral valves that appeared unsuitable for commissurotomy were excised in toto at the time of mitral valve replacement in 15 patients. The excised valves were mounted in a fluid-filled chamber with a window for photographic evaluation. The chamber was perfused continuously to ensure maximal valvular opening. The valve was photographed, and the orifice area was measured before and after balloon expansion. In addition, the specimens were examined macroscopically and radiographically with regard to calcium content and degree and localization of fibrosis. These data were correlated with splitting of commissures and with rupture of leaflets. Nine valves were fibrotic, and six were calcific. Dilatation was performed first with a single-balloon catheter (diameter, 2 cm) and then with a double-balloon catheter (diameter, 2 and 1.5 cm). After dilatation with one balloon, the average mitral valve area increased from 0.79 to 1.09 cm2, and with two balloons, average area increased to 1.59 cm2. The single-balloon technique caused commissural splitting in nine valves, stretching in three, partial leaflet rupture in one, and no change in two. After the double-balloon technique, commissural splitting occurred in 12 valves and three leaflets were ruptured where severe fibrosis and calcification were mainly located within the commissures. As a rule, after dilatation with the single-balloon technique, the remaining stenosis was still severe, and after dilatation with the double-balloon technique, the remaining stenosis was moderate.(ABSTRACT TRUNCATED AT 250 WORDS)

Calcinosis↗
PubMed1990

Retardation of development and progression of coronary atherosclerosis: a new indication for calcium antagonists?

Development of atherosclerotic lesions in animals, preferrably induced by a high-cholesterol diet, can be successfully suppressed by calcium channel blockers such as verapamil, nifedipine, nicardipine and diltiazem. The issue of a beneficial effect of calcium channel blockers on human coronary atherosclerosis is however not yet settled. At present, three prospective randomized clinical trials with calcium channel blockers (Nifedipine, Verapamil, Nicardipine) are being conducted (INTACT, FIPS, Study of the Montreal Heart Institute). Target variable for assessment of progression in these studies is the severity of coronary atherosclerosis evaluated by angiography both at entry into the study and after 2-3 years of treatment. A total of 445 patients after coronary bypass surgery (CABG) were entered in FIPS (Frankfurt Isoptin Progression Study) and randomly allocated to either verapamil 120 mg t.i.d. or placebo. The extent of coronary atherosclerosis is assessed by repeat angiography both 1 year and 3 years after randomization. Three vessel regions are evaluated separately. 1. Native vessels without bypass grafts and segments distal to the peripheral graft anastomosis ("core region") 2. Segments bridged by bypass grafts and 3. Bypass grafts. The 1-year follow-up was completed by 162 patients (Group A = 80 patients; Group B = 82 patients). There was a homogeneous distribution in the two groups for all clinical variables, graft patency rates, and the incidence of clinical events (myocardial infarction, need for cardiac surgery or PTCA, cardiac death). The overall progression rate of atherosclerosis in the first year was expectedly low.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

[Protective function of collaterals in percutaneous transluminal coronary angioplasty].

UNLABELLED: With increasing application of PTCA, it will become necessary to identify patients (p) who can be dilated without expensive surgical standby. In 82 p with angina pectoris and stress-induced ischemia and without transmural myocardial infarction, the following parameters were measured during coronary angioplasty (PTCA): angina pectoris (AP), epicardial ST-segment displacement (via long wire), and aortic pressure. In 26 p, the affected vessel showed retrograde filling (A) via collaterals (CL). In 24 p CL were identified without retrograde filling (B) and 32 p were without CL (C). The balloon was inflated three to eight times over periods of 30 to 90 s. [table; see text] CONCLUSIONS: In vessel occlusion caused by PTCA, a myocardial infarction will occur in more than 80% of p without visible CL, and rarely in the presence of CL. Therefore, PTCA of vessels with retrograde filling appears safe. Furthermore randomized studies are necessary to determine if strict surgical standby is required in such cases.

Angina Pectoris↗
PubMed1989

[Acute and subchronic effect of a patch with discontinuous nitroglycerin liberation].

We investigated a new patch with 15 mg nitroglycerine and a drug release of 70% during the first 12 h of application, designed to prevent tolerance. In a double blind placebo controlled trial 12 patients with angiographically significant coronary artery disease, angina and reproducible ST-segment depression during exercise were studied. Stress-tests with a constant workload were performed before, 1 h, 4 h and 8 h after first day application as well as after 8-10 days of therapy. At the first day the sum of ST-segment depression (lead V 5) during each minute of exercise and the 5 minutes of recovery decreased by 55.5% (1 h, p less than 0.001), 47.4% (4 h, p less than 0.001) and 28.4% (8 h, n.s.). After subchronical application the relative values were 32% (1 h, p less than 0.05), 23.8% (4 h, n.s.) and no change after 8 h. Thus the new patch is effective between 1 h and 8 h of acute application. With chronic therapy however tolerance occurs despite the fact that only a small amount of nitroglycerine is released during the last half of a 24 h application.

Administration, Cutaneous↗
PubMed1988

[Color Doppler echocardiography and radionuclide ventriculography in aortic and mitral valve insufficiency].

In 99 stable patients with auscultatory findings of aortic (n = 52) or mitral regurgitation (n = 47), the regurgitant fraction was determined by radionuclide ventriculography (RNV). In addition, color-coded Doppler echocardiography (CDE) was performed to assess semi-quantitatively the severity of valve incompetence. In aortic regurgitation, the results of both methods concurred in 73% of cases. With CDE, the regurgitation was underestimated in 10% by one class and overestimated in 17% by one class. In mitral regurgitation the results concurred only in 60% of the patients. CDE seemed to overestimate the incompetence, by one class, in 19% and to underestimate the lesion in 21% of the patients. In 2/47 patients the difference was more than one class. In conclusion, both noninvasive methods are applicable to assess the severity of mitral and aortic regurgitation. The RNV appears superior in follow-up assessment because of a slightly better reproducibility and investigator-independence.

Adult↗
PubMed1988

[Detection of calcium in mitral valve diseases using computer-assisted 2-dimensional echocardiography].

In order to detect mitral valve calcification, 31 consecutive patients were examined using two-dimensional echocardiography 1 day before mitral valve replacement. Calcifications of the valve were diagnosed by digital image control (grey-scale manipulation using S-curve and reject control). After the operation, the excised valves were X-rayed to determine the degree of calcification. Calcifications of the mitral valve were found by echocardiography with a sensitivity of 89.5%, a specificity of 91.7% and a predictive accuracy of 90.3%. The degree of calcification, however, was underestimated in 47%. The results show that the described grey-scale manipulations are a reliable method of detecting calcifications of the mitral valve by echocardiography. This enables the preoperative identification of those patients who are suitable for mitral valve commissurotomy.

Calcinosis↗
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

Long-term treatment of severe chronic heart failure with captopril: a double-blind, randomized, placebo-controlled, long-term study.

Twenty-three patients with severe heart failure (NYHA classes III and IV) on treatment with digitalis and diuretics were additionally treated in a randomized double-blind study over a 6-month period with captopril (n = 12; mean daily dose 84 mg) or a placebo (n = 11) and were then reexamined. In the captopril group, the left-ventricular filling pressure decreased by 9 mm Hg (from 23 to 14) at rest and 6 mm Hg (from 35 to 29) during exercise. In the placebo group, there was an increase of 4 mm Hg (from 25 to 29) at rest and 7 mm Hg (from 33 to 40) during exercise; p less than 0.01 (p less than 0.01). In the captopril group, the cardiac index at rest increased 0.7 1/min/m2 (from 2.1 to 2.8) and during exercise 1.2 1/min/m2 (from 2.8 to 4.0). In the placebo group, the increase in cardiac index was considerably less pronounced at rest (= 0.2 1/min/m2; from 1.9 to 2.1) and during exercise (= 0.1 1/min/m2; from 2.7 to 2.8); p less than 0.02 (p less than 0.01). The improved cardiac output had a beneficial effect on the renal blood flow. Hippuran clearance increased by 46 ml/min (from 271 to 318), whereas in the control group it decreased 25 ml/min (from 259 to 234) (p less than 1.02). Both the heart rate and the arterial blood pressure remained constant, whereas the decrease in peripheral vascular resistance was definitely more pronounced in the captopril group (= 562 dyne X s X cm-5, from 1,841 to 1,279) than in the placebo group (= 123 dyne X s X cm-5, from 1,834 to 1,710; p less than 0.02). The heart volume, assessed radiographically, increased slightly in the placebo group, and the left-ventricular end-diastolic diameter remained constant in both groups. In the course of the study, two patients died in the captopril group and three in the placebo group. After six months, eight patients in the captopril group and three in the placebo group had improved by at least one NYHA category. The beneficial effects of captopril are due to its inhibitory effect on the renin-angiotensin system as well as to the inhibition of sympathetic stimulation. Consequently, in the captopril group the quantity of plasma norepinephrine decreased by 188 ng/ml (from 430 to 618); p less than 0.03. The indirect vasodilation caused by this mechanism leads to persistent unloading of the myocardium and an improvement in heart failure without loss of action by counterregulatory mechanisms.

Captopril↗
PubMed1987

[Muscular obstruction of the right ventricular outflow tract. Subvalvular pulmonary stenosis or hypertrophic cardiomyopathy?].

A case is reported of right ventricular outflow obstruction caused by hypertrophic cardiomyopathy. The pressure gradient between the inflow tract and the outflow tract of the right ventricle was 84 mm Hg. Resection of the hypertrophic muscle bundles practically eliminated the obstruction leaving only an insignificant subvalvular gradient of 2 mm Hg. Histologic examination revealed cardiac muscle cell hypertrophy and disorganization.

Adult↗
PubMed1986

Effects of bepridil on regional myocardial ischemia and comparison with verapamil.

This study was designed to assess the efficacy of bepridil in reducing regional myocardial ischemia and to compare its efficacy with that of verapamil. Forty-five anesthetized, open-chest dogs were subjected to three 5-minute occlusions of the left anterior descending coronary artery (LAD), each followed by 45 minutes of reperfusion. Eleven dogs (group 1) served as controls. In 10 dogs, bepridil, 5 mg/kg, was administered before the third occlusion (group 2). In 11 dogs, verapamil was administered before the third occlusion (group 3). In each dog, on-line intramyocardial hydrogen ion concentration and carbon dioxide tension were measured in the myocardial segment supplied by the LAD. Regional myocardial contractility was assessed in this area with 2 pairs of ultrasonic crystals inserted to determine percent segmental shortening. Regional myocardial blood flow was determined during each occlusion by washout of xenon-127. The increase in hydrogen ion concentration and carbon dioxide tension did not change from occlusion 2 to occlusion 3 in the control group. Both bepridil and verapamil elicited a significant reduction in the extent of regional ischemia, evidenced by a reduction in the accumulation of hydrogen ions, in occlusion 3 vs occlusion 2. Systolic bulging occurred during all occlusions and the periods of reperfusion were not sufficient to allow complete recovery of regional function. Bepridil and verapamil each caused a significant increase in percent segmental shortening (both p less than 0.025), and verapamil effected a significant improvement of function during occlusion 3 compared with occlusion 2.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

Effects of bepridil on heart mitochondrial membrane and the isolated rat heart preparation.

Bepridil (Cordium) was found to activate rat heart mitochondrial membrane-bound ATPase at concentrations of 10 nmol/l-10 mumol/l. By contrast, oligomycin-sensitive ATPase from beef heart mitochondria was inhibited at concentrations of 1-10 mumol/l. In both systems sensitivity toward the inhibitor oligomycin was reduced. Under the influence of the drug, RCR (coupling degree of electron transport to ATP synthesis), ST3 (oxygen uptake in presence of substrate and ADP) and OPR (oxidative phosphorylation rate, amount of ATP synthesized in mitochondrial metabolic state ST3) values are reduced, indicating partial inhibition of oxidative phosphorylation. At 0.25 mumol/l concentration of bepridil, in the isolated normoxic working rat heart preparation aortic flow was reduced to zero. No changes in oxidative phosphorylation parameters were found in mitochondria isolated from these preparations. In the isolated, working rat heart preparation bepridil at a concentration of 0.05 mumol/l reduced aortic flow to about 75% of its original value. In this preparation, no cardioprotective effects (neither on aortic flow nor on mitochondrial function) could be demonstrated during postischemic reperfusion. It is suggested, that in vitro mitochondrial activities of bepridil are not related to in vivo action of the drug.

Adenosine Triphosphatases↗