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Biomedical subjects

J Barmeyer

Publications and source records attributed to J Barmeyer.

At least 37 records · Page 2Linked to original sources
PubMed1997

[Structural analysis of 16 different coronary stent systems].

Parallel with the increasing number of coronary stent implantation procedures, new or more elaborate coronary stents were introduced into clinical use almost every month in 1996. We have studied the architecture, surface-morphology, and shape-conversion of 16 different coronary stent systems. The objective of our study was to detect possible specific design and surface features which might influence the healing process in stent restenosis and stent thrombosis. Using electron microscopy we found ultrasmooth surfaces on 5 stents. All other coronary stents revealed individually varying and partly sharp-edged surface irregularities. Video-based morphometry showed covering between 8.3% and 26.4%. Stent shortening after in-vitro expansion ranged from 0% up to 10.5% of the initial stent length. In some stent systems balloon dilation lead to over-expansion of the stent margin. This over-expansion amounted up to 20% of the balloon diameter and the stents revealed a rather biconcave than homogeneous expansion pattern. This phenomenon was also found after postmortal stent implantation in 20 autopsied hearts.

Angioplasty, Balloon, Coronary↗
PubMed1997

High Pressure Coronary Stenting: Efficacy and Safety of Aspirin Versus Coumadin Plus Aspirin Ñ Preliminary Results of a Randomized Study.

The efficacy and safety of treatment after coronary stenting was examined with aspirin alone, 100 mg daily, as compared to coumadin plus aspirin. Data from the first 101 patients, 73 men and 28 women, aged 59.2 +/- 9.3 years, of a prospective randomized study are presented in this preliminary report. Forty-eight patients suffered from one-vessel disease, 32 had two- and 21 three-vessel disease. Indications for stenting were stable angina in 65 patients, unstable angina in 16, threatening myocardial infarction in 4 and restenosis in 16 patients. The stents were implanted by high pressure balloon inflation (14.5 +/- 2.2 atm), 55 of them were Palmaz-Schatz, 31 Micro, 10 Gianturco-Roubin, 2 Wiktor and 3 combined stents. Intravascular ultrasonographic guidance was not performed. The primary end point was defined as the absence of the following events: death, subacute coronary artery closure, acute myocardial infarction, emergency coronary bypass surgery, repeated PTCA, major bleeding or arterio-venous aneurysms needing transfusion or surgery. Eighty out of 101 patients (79.2%), 41 out of 47 (87.2%) in the aspirin group and 39 out of 54 (72.2%) in the coumadin plus aspirin group (p = 0.06) were free of events during hospitalization (9.5 +/- 5.7 days, median: 8 days). Forty-five out of 47 patients (95.7%) in the aspirin and 51 out of 54 (94.4%) in the coumadin plus aspirin group (p = 0.8) were without subacute closure. One death occurred in the aspirin group due to stent abscess two weeks after an angiographically successful stent recanalization. All 7 arterio-venous aneurysms with surgical interventions occurred in the coumadin group (p = 0.01). No emergency bypass surgery had to be performed. If these preliminary results will be confirmed by the final analysis, the combination of coumadin with aspirin does not show more efficacy or safety as compared with aspirin alone in the treatment after high-pressure coronary stenting during the hospital stay.

Journal Article↗
PubMed1996

[Evaluating the measuring accuracy of intravascular ultrasound].

AIM: Intravascular ultrasound investigations are new tomographic imaging methods for evaluation of artery dimensions and wall morphology. The present study was performed to test accuracy and observer variability. METHOD: 3 plastic phantoms and 1 iliacan artery were assessed. The quantitative measurements were made by computerised 3D reconstruction. RESULTS: The plastic phantoms showed ultrasonically three layers of echogenic structures. An intimal fibrous thickening was seen in the iliac artery. The cross sectional diameters were ultrasonically overestimated by 12.6 +/- 5.6%. Due to the lower velocity of sound in water than in blood there were no significant differences to the true diameters. The intra- and interobserved variabilities were determined to 1.4 +/- 0.8% and 2.6 +/- 1.2%. CONCLUSIONS: Intravascular ultrasound provides a reproducible method for measuring vessel lumen diameters with excellent intraobserver and interobserver variabilities. For in vitro examinations the different velocities of sound in different media have to be taken into account.

Humans↗
PubMed1995

[Effect of the degree of revascularization on left ventricular function after aortocoronary bypass operation].

BACKGROUND: The extent of myocardial revascularisation by aortocoronary bypass surgery can only be quantitatively evaluated by using precise criteria. In this retrospective study the effect of coronary surgery on left ventricular function was analyzed. PATIENTS AND METHODS: In 161 patients, 148 male and 13 female, aged 52.5 +/- 7.0 years (33 to 69 years) with 1 (7%), 2 (38%) or 3 vessel disease (55%) the left ventricular function was analyzed by Swan-Ganz catheterization at rest and on exercise, five months before and after coronary bypass operation. Coronary artery and bypass lesions were quantified according to a new detailed score including diseased main or side branches, segment 1 to 3, type of irrigation and area reduction of the artery cross-section. Pulmonary capillary wedge pressure and cardiac index were measured and related to the grade of revascularisation (RG) and pre-operative ejection fraction (EF), classified in the groups RG1 < 50%, n = 54; RG2 50 to 74%, n = 52; RG3 > or = 75%, n = 55, EF1 < 60%, n = 30 and EF2 > or = 60%, n = 129. RESULTS: The change in pulmonary capillary wedge pressure on exercise was in RG1, RG2 and RG3 -26.2%, -29.0% and -40.9%, respectively (p < 0.001). It was significantly higher in RG2 and RG3 than in RG1. The increase in cardiac index on exercise was significant only in groups RG2, RG3 and EF2 (p < 0.005). CONCLUSION: Adequate improvement of left ventricular function can be expected when a grade of revascularisation of 50% and more is achieved.

Adult↗
PubMed1994

[Diagnostic value of right thoracic ECG recording in detection of pulmonary hypertension in chronic obstructive respiratory disease].

There are many electrocardiographic criteria of pulmonary hypertension and cor pulmonale. These criteria are generally highly specific but not sensitive. Therefore many patients with pulmonary hypertension remain undetected. The aim of this study was to delineate a sensitive as well as a specific ECG parameter for noninvasive prediction of pulmonary hypertension under special consideration of the right thoracic leads. 75 patients were included in this study, 62 male and 13 female, mean age 62.7 +/- 9.5 years. All presented with chronic obstructive lung disease known since 12.1 +/- 9.7 years. The underlying disease had been confirmed clinically and by body plethysmography. Laboratory and lung function data showed a high air way resistance with a mean value of 6.8 +/- 3.3 cm H2O/l/s and a high intrathoracic gas volume of 149.1% of the expected value. The severity of hypoxemia was variable but generally moderate with a PaO2 of 65.3 +/- 11.6 mm Hg on average. All patients applied aerosols with ipratropiumbromid, fenoterol and glucocorticoids. 92% additionally received aminophylline and 87.0% oral glucocorticoids. Diuretics and glycosides were prescribed in 50.0% and 34.8% respectively. The four right thoracic ECG leads Vr3 to Vr6 were recorded in addition to the common twelve leads I to III, a VR, aVL, aVF and V1 to V6. A modified Sokolow-Lyon-Index (SIm) as a sum of amplitudes of R in lead Vr3 and S in lead V6 and the combination of SIm with PaO2 (SIm-PaO2, n = 44) according to the formula SIm + 0.02 (100--PaO2%) were established. Additionally a right heart catherization by Swan-Ganz technique was performed. The mean values of hemodynamic data demonstrated a constellation of precapillary pulmonary hypertension with high PAPm and pulmonary resistance and low pulmonary capillary wedge pressure (26.4 +/- 12.9 mm Hg, 396.0 +/- 294.0 dyn.s./cm5 and 8.7 +/- 4.2 mm Hg, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1993

Two-dimensional echocardiographic assessment of right cardiac pressure overload in patients with chronic obstructive airway disease.

Two-dimensional echocardiography was used to estimate right cardiac pressure overload in patients with chronic obstructive airway disease. Area measurements of the four heart chambers were carried out from the apical four-chamber view. Additionally, the respiratory behaviour of the inferior vena cava was examined from the subcostal view. A good apical imaging of the four-chamber view for area measurement was obtained in 44 out of 48 patients with chronic obstructive airway disease. The respiratory behaviour of the inferior vena cava was investigated from the subcostal view in 38 patients. Within 8 days after echocardiography, right cardiac catheterization was carried out in order to measure pulmonary artery and right atrial mean pressures and to determine pulmonary vascular resistance. A good correlation was found between pulmonary artery mean pressure and the following echocardiographic parameters: area index (area/body surface) of the two right heart cavities (r = 0.83), right-to-left ventricular area ratio (r = 0.82) and right-to-left cardiac area ratio (ratio between the added areas of both right heart cavities on the one side and the added areas of both left heart cavities on the other; r = 0.82). Correlation between these parameters and pulmonary vascular resistance (r = 0.71, 0.66 and 0.71, respectively) and between the right atrial mean pressure and the right atrial area index was less close (r = 0.64). On the other hand, the respiratory behaviour of the inferior vena cava proved to be highly specific but not very sensitive in predicting a pathological right atrial pressure.(ABSTRACT TRUNCATED AT 250 WORDS)

Atrial Function, Right↗
PubMed1993

[The long-term effect of molsidomine on frequency of hemorrhage, portal and cardiac hemodynamics in patients with liver cirrhosis--a pilot study].

The aim of the study was to examine the effects of maintenance molsidomine therapy on portal and cardiac haemodynamics in patients with confirmed alcoholic or nonalcoholic liver cirrhosis and portal hypertension. Molsidomine is a selective reducer of preload without development of tolerance. 16 patients with portally decompensated cirrhosis of the liver following an initial or recurrent episode of bleeding form oesophageal/fundal varices were on long-term treatment (4-24 months) with 2 or 3 x 8 mg molsidomine/day (Corvaton retard). They were followed up after 3-6 months. 6 of the 16 had been treated previously with propranolol for haemorrhage prophylaxis over 11 +/- 15 months. In a total of 70 treatment months with propranolol, 10 recurrent bleeds had occurred. During 166 treatment months with propranolol, 10 recurrent bleeds had occurrences of bleeding. This long-term treatment showed reductions in hepatic venous pressure gradient of 24.8% (n = 8) (p < 0.05), variceal pressure of 28.7% (n = 7) (p < 0.05) and size of varices of 17% (n = 8). This occurred without any clinically relevant impairment of systemic cardiovascular regulation. Therefore long-term therapy with molsidomine may be suitable for prophylaxis of haemorrhage of oesophageal varices.

Adult↗
PubMed1992

[The importance of 201-thallium myocardial scintigraphy in the hypertensive patient].

Thallium-201 exercise myocardial scintigraphy was performed in 57 patients (37 males, 20 females; mean age 55.4 [43-78] years) with angina and systemic hypertension after exclusion by coronary angiography of any coronary macroangiopathy. The exercise ECG of 32 patients could not be used in the diagnosis of ischaemia because of the presence of left ventricular hypertrophy with abnormal repolarization or left bundle branch block. Abnormal haemodynamics were demonstrated at cardiac catheterization in 23 patients (Swan-Ganz). Only 10 of the studied hypertensives with normal coronary angiograms had a myocardial scintigram within normal limits, while 12 had extensive ischaemic zones in the left ventricle. All patients with left bundle branch block had evidence of exercise-dependent apical "ischaemia". Thallium-201 myocardial scintigraphy should not be used as a screening method in hypertensives with angina, because the high proportion of "false-positive" findings, in the sense of a macroangiopathy, will nevertheless require early invasive diagnosis.

Adult↗
PubMed1992

Efficacy and safety of APSAC in the treatment of acute myocardial infarction.

A prospective, open, multicentre post-marketing surveillance on the efficacy and safety of intravenous APSAC in the treatment of acute myocardial infarction was performed in 2436 patients. Reperfusion suggested by non-invasive parameters was achieved in 77.3% of patients. In-hospital mortality was low (7.1%). After exclusion from analysis of patients greater than 70 years of age and those reported to be in cardiogenic shock, mortality rate was 2.9%. More importantly, non-invasive evidence for successful thrombolysis resulted in a significantly lower mortality (3.3%) compared with patients without evidence of successful reperfusion (17.2%). The incidence of serious adverse events was low (132 in 2436 patients, 8/2436 = 0.3% fatal). The data from this post-marketing surveillance conducted under every-day clinical conditions confirm the efficacy and safety of APSAC as a thrombolytic agent in acute myocardial infarction, as demonstrated previously in controlled clinical trials.

Acute Disease↗
PubMed1992

Aerobic capacity in rate modulated pacing.

Whether heart rate or AV synchrony is the most important factor for an increase in aerobic capacity was evaluated in a comparative study between sinus bradycardia, VVIR, DDD, and DDDR stimulation. Sixteen patients (mean age 67 years) with chronotropic incompetence and implanted DDDR pacemaker (Telectronics META 1250) were randomly studied by cardiopulmonary exercise testing. All patients were exercised to their anaerobic threshold (AT) with the following heart rates: DDD 84 +/- 3, VVIR 110 +/- 5, and DDDR 116 +/- 6 beats/min. Mean oxygen uptake (VO2, mL/kg per min) at AT was 7.4 +/- 0.3 in DDD and VVIR modes. A 12% increase was measured in DDDR mode (8.3 +/- 0.4). Compared to VVIR work capacity in the DDDR mode was improved by 17% (41 vs 48 W/min). In patients with isolated sinus node disease (n = 9) the increase of VO2 and work capacity at AT during DDDR mode was more pronounced (16% and 20%, respectively, compared to VVIR). In patients with intermittent second or third degree AV block (n = 7) the differences between the pacing modes were not significant. This might partly be due to a lesser degree of chronotropic incompetence in this subgroup. In conclusion only the conjunction of heart rate increase and preservation of AV synchrony provides a significant improvement in aerobic capacity during exercise.

Aged↗
PubMed1991

[The effect of molsidomine on portal and cardiac hemodynamics in liver cirrhosis].

An investigation was conducted on 21 patients (16 men and five women; mean age 48.2 [34-67] years) with cirrhosis of the liver of various aetiologies to determine whether molsidomine, which selectively reduces pre-load with-out the development of tolerance, effects portal and cardiac haemodynamics in liver cirrhosis and portal hypertension. Intravenous injection of 2 mg molsidomine reduced the hepatic vein closing pressure after 30 min by 8% (P less than 0.05) and the hepatic vein closing pressure gradient by 13.4% (P less than 0.002). The cardiac output fell by 5.8% (P less than 0.02) and the mean systemic arterial pressure by 4.2% (P less than 0.003). The reduction in hepatic venous closing pressure gradient did not correlate with the fall in cardiac output and mean arterial pressure. In 15 of 21 patients the hepatic venous pressure fell, but in six patients (28.6%) the pressure was not reduced (non-responders). The latter failure of response was associated with marked ascites, significant functional liver decompensation and alcoholic liver cirrhosis. Preliminary long-term observations with molsidomine point to a reduction in portal pressure by as much as 40%. This suggests that the drug is suitable for preventing bleeding from oesophageal varices.

Adult↗
PubMed1991

[Intolerance reactions to ionic and nonionic contrast media in cardiac diagnosis. A randomized double-blind study].

Reactions to an ionic and a nonionic contrast medium were compared in a randomized double-blind trial involving 1153 patients (897 men, 256 women; mean age 56 [18-84] years) who underwent left-heart catheterization with coronary angiography. 584 patients (group 1) received the ionic contrast medium meglumine diatrizoate (Urografin 76%), while 569 (group 2) received the nonionic iopromide (Ultravist -370). Reactions of skin and mucosae, heart and circulation, lungs and respiratory tract, as well as of the central nervous system were noted. There was no significant difference between the two groups with respect to age, weight, height, allergic predisposition, left-ventricular ejection fraction, or serum electrolyte concentrations. Mild reactions, not requiring any treatment, occurred in 108 of the 1153 patients (9.4%), 85 (14.6%) in group 1 and 23 (4%) in group 2 (P less than 0.001). Severe reaction requiring treatment occurred in eight patients of group 1 (1.4%) and 14 of group 2 (2.5%)--difference not significant. Ventricular fibrillation was more frequent among group 2 patients (four compared with one in group 1), while two of three asystoles requiring treatment occurred in group 1 patients. The results show that, while mild reactions not requiring treatment were clearly less frequent after nonionic contrast medium injection, the risk of severe reactions was not reduced by their use.

Adolescent↗