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Biomedical subjects

V Hossmann

Publications and source records attributed to V Hossmann.

At least 19 recordsLinked to original sources
PubMed1997

Cardiac risk stratification for high-risk vascular surgery.

BACKGROUND: The best strategy for cardiac risk assessment before high-risk vascular surgery remains controversial. A cardiac risk stratification protocol was evaluated in patients undergoing high-risk vascular surgery. Our investigation paralleled the elaboration of the American College of Cardiology/ American Heart Association (ACC/AHA) Guidelines for Perioperative Cardiovascular Evaluation for Noncardiac Surgery and is highly comparable to the proposed guidelines. METHODS AND RESULTS: A cardiac risk stratification protocol was evaluated prospectively in 203 patients scheduled for aortic surgery. Key points of the study were cardiac mortality/morbidity and cost-effectiveness. Patients were stratified into low (n = 101), intermediate (n = 79), and high (n = 23) cardiac risk after clinical predictors. After stratification, the degree of estimated functional capacity assessed by treadmill exercise and daily living activities and expressed by metabolic equivalents (METs) was critical for further cardiac evaluation. In intermediate-risk patients with an estimated functional capacity < 5 METs and in all high-risk patients, noninvasive cardiac testing and/or subsequent medical care were performed. Noninvasive testing was considered necessary in 41 patients, coronary angiography in 7, and myocardial revascularization in 1. Overall hospital mortality was 3.5%. Cardiac mortality and morbidity were 1% and 12.4%, respectively. CONCLUSIONS: Cardiac risk stratification for high-risk vascular surgery patients, according to a protocol similar to the ACC/AHA Guidelines for Cardiovascular Evaluation for Noncardiac Surgery, demonstrated excellent clinical outcome. This approach appears to be a safe and economical strategy for preoperative cardiac evaluation.

Aorta↗
PubMed1988

[Scintigraphic imaging of adrenergic structures of the heart with 123(I)-metaiodobenzylguanidine in cardiomyopathy].

In 14 patients with various kinds of cardiomyopathy (DCM, HCM with and without obstruction, latent cardiomyopathy (= LCM], after confirmation of diagnosis, myocardial imaging with the recently developed substance 123I-metaiodobenzylguanidine (MIBG), an analog to guanethidine, was performed. In comparison, four patients in whom cardiac disease had been excluded, were evaluated. Myocardial uptake and washout were evaluated quantitatively. As a result, each kind of cardiomyopathy showed a significantly higher activity uptake versus normals, especially in patients with DCM. In all patients, the washout rate was increased compared to normals. The higher uptake is caused by depletion of catecholamine stores, as already known in DCM. On the other hand, the increased washout rate is considered to be a sign of a high sympathetic tone found in patients with HCM and LCM. The results seem to demonstrate a primary or secondary involvement of the sympathetic nervous system in these entities of hitherto unknown etiology.

3-Iodobenzylguanidine↗
PubMed1987

[Atropine in intraoperative isorhythmic AV dissociation].

40 patients of the ASA groups I and II in whom intra-operatively an isorhythmic AV dissociation occurred under inhalation narcosis with halothane or enflurane, were examined in a randomized study. Within an observation period of 15 minutes the spontaneous rate of return to the sinus rhythm was 20 per cent (group A, n = 20). Intravenous administration of 0.01 mg/kg atropine sulphate produced a significantly higher rate of return of 80% within the same period. On the whole, no influence on arterial blood pressure was noted. Atropine increases the heart rate by 32%, and this is considered to be an important drawback. The possibility of influencing the AV dissociation via atropine points to the pathogenetic importance of the vagus in so far as it acts as a depressant on the sinus node.

Adolescent↗
PubMed1987

[Comparative study of circulatory and ECG-changes after supraclavicular plexus block with bupivacaine-HCl 0.5 per cent in patients with chronic kidney failure].

The systemic effects of local anesthetic drugs, especially bupivacaine, on myocardial conduction and the increase of cardiotoxicity by hypoxemia, acidosis, and hyperkalemia has been proven in numerous animal experiments. In our department, supraclavicular brachial block with bupivacaine is the method of choice for patients with chronic renal failure requiring operations of the upper limb. The question may be raised whether or not these patients with their concomitant disease--electrolyte and acid-base imbalances, uremic cardiomyopathy--are especially endangered by the use of this drug. Supraclavicular brachial blockade (3 mg/kg bupivacaine 0.5% + 0.1 IU vasopressin/ml) was performed in 10 patients with chronic renal failure requiring hemodialysis. The control group consisted of 10 healthy patients who were admitted for minor hand surgery. Preoperative blood samples were taken for measurements of blood urea nitrogen, serum creatinine, serum electrolytes, and arterial blood gas analysis. Long-term ECG monitoring begun 20 min before injection of the block and continued over a total of 200 min. Serum concentrations of bupivacaine were determined at 10, 20, 30, 60, 120, and 180 min after injection. Comparing the two groups, no severe changes in electrolytes or acid-base status could be found despite some statistical significances. Even though bupivacaine serum concentrations proved to be 3 times higher in the study group than in the control group, no changes in cardiac conduction could be registered. We conclude that bupivacaine is as safe in dialyzed patients with chronic renal failure with regard to possible changes in circulatory parameters and myocardial conduction as in healthy patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Chemical Analysis↗
PubMed1986

Antiplatelet effects of intravenous iloprost in patients with peripheral arterial obliterative disease. A placebo-controlled dose-response study.

The dose-dependent inhibition of platelet aggregation by the chemically stable, prostacyclin-mimetic, iloprost, was studied in patients suffering from stage II-III peripheral arterial obliterative disease (PAOD). The study was designed as a randomized placebo-controlled cross-over trial. Iloprost was administered i.v. to six patients at doses of 0.5, 1.0, 2.0 or 3.0 ng/kg X min for 4 h, with an interval of 2-3 days between the infusions. During iloprost infusion, systolic and diastolic arterial blood pressure, heart rate and blood flow in the affected limb remained unchanged. In contrast, there was a considerable, dose-dependent inhibition of ADP- and thrombin-induced platelet aggregation and secretion ex vivo at doses of 0.5-2.0 ng/kg X min iloprost, indicating that iloprost reduced platelet stimulation by 50%-70%. The antiplatelet action of iloprost remained unchanged during infusion but ceased with 2 h after administration had ended. The agent was tolerated by the patients without unacceptable side-effects at doses up to 2 ng/kg X min. It is concluded that iloprost administered i.v. at doses of 1-2 ng/kg X min in patients with stage II-III PAOD does not involve haemodynamic side-effects and might be considered an effective antiplatelet agent.

Adult↗
PubMed1986

Blood viscosity: a pathogenetic factor in the development of essential hypertension?

Inhibition of the ouabain-sensitive Na-K-ATPase by digoxin significantly decreases erythrocyte deformability (5). Since first a decrease in this transport system has been discussed as a pathogenetic factor in the development of essential hypertension and second an increase in blood viscosity, due to an increased hematocrit has been observed in elderly hypertensives, hemorheology and sodium transport systems were examined in adolescent hypertensives and compared with age-matched normotensive controls. 73 normotensives (N; mean blood pressure 127/80 mmHg) and 53 hypertensives (H; mean blood pressure 147/94 mmHg) aged 23-27 yrs were randomly selected from an epidemiological survey, covering 1342 adolescents. While apparent whole blood viscosity at different shear rates, hematocrit, plasma fibrinogen were not significantly different, erythrocyte deformability, measured with a positive pressure filter system (pore phi 5 mu) and expressed as Q = delta P/ery.susp.Hct 10%/delta P/plasma was significantly attenuated with Q = 1.77 +/- 0.05 in H, compared to 1.64 +/- 0.04 in N (p less than 0.05) The decrease in erythrocyte deformability was not accompanied by an inhibition of the Na-K-pump nor of total K+-uptake in erythrocytes, both measured with the 86Rb uptake. There was only a slight increase in Na+-excretion in urine of 184.4 + 12.2 mval in H, compared to 162.0 +/- 10.4 mval in N (n.s.). K-/+-excretion and serum electrolytes did not show any difference. Whether the decrease in erythrocyte deformability may contribute to an increase in peripheral vascular resistance in essential hypertension has to be further clarified.

Adult↗
PubMed1986

Vasopressor and vasodepressor hormone-systems in adolescent hypertension.

We investigated the activity of the renin-angiotensin-aldosterone-system, the secretion of catecholamines and the kallikrein-kinin-system in 126 adolescents randomly selected from a large study of 1342 young people examined in an epidemiological survey conducted in Cologne in 1975, 1976 and 1980. 73 of them with arterial blood pressures below 145/90 mm Hg were called "normotensives" (systolic blood pressure 127.2 +/- 1.0 mm Hg, diastolic bp 79.7 +/- 0.8 mm Hg). They were compared with 53 "hypertensives" (systolic blood pressure 147.2 +/- 1.6 mm Hg, diastolic bp 93.7 +/- 1.1 mm Hg). Urinary catecholamines were significantly higher in the hypertensives (155.0 +/- 13.3 micrograms/d) compared to the normotensives (100.7 +/- 5.3 micrograms/d) (p less than 0.001) whereas plasma levels of adrenaline and noradrenaline were similar. Serum aldosterone levels and plasma-renin-concentrations were not different between the two groups. Angiotensin-converting-enzyme-activity was slightly higher in the hypertensive group (107.1 +/- 3.5 U/l versus 98.0 +/- 2.6 U/l, p less than 0.001). Urinary kallikrein excretion was found to be modestly lower in hypertensives compared to normotensives (0.40 +/- 0.05 versus 0.55 +/- 0.06 mU/mg creatinine). Urinary excretion of sodium and potassium, blood levels of glucose, uric acid, cholesterol and triglycerides were similar in both groups. The results of the present study suggest an increased sympathetic activity in the early stage of hypertension in adolescents.

Adolescent↗
PubMed1985

[Arteriosclerotic changes in the carotid arteries in patients with hypersensitive carotid sinus reflex].

Thirty-seven patients (15 female, 22 male; aged 46-89 years, mean age 68.8 years) with III or IV grade carotid sinus reflex carotid arteries were investigated by sonography (B-scan and CW-Doppler). It was demonstrated that stenoses or arteriosclerotic plaques, localized in the region of the carotid bulb or bifurcation, were present on both sides in 27 patients and on one side only in four patients. Five patients did not show these changes and four of them had thickening of common carotid artery endothelium. Thus, vascular changes occurred in 35 patients. Occlusions and stenoses greater than 50% were visible in five patients. Primarily bilateral changes were shown as well as unilateral and bilateral pathologic reflex response; main localization was the posterior wall of the carotid bulb. Thus, arteriosclerotic changes seem to be important in the development of pathologic carotid sinus reflex. Cerebral complications (left-sided PRIND) occurred in one patient who did not have high degree carotid stenosis. In comparison to other authors who investigated only with CW-Doppler a much higher rate of arteriosclerotic wall changes and a greater occurrence of bilateral changes could be demonstrated by application of the highly sensitive B-scan sonography.

Aged↗
PubMed1985

High-resolution real-time ultrasound of the carotid bifurcation in patients with hyperactive carotid sinus syndrome.

The carotid bifurcations and the common carotid arteries of 36 patients with the diagnosis hyperactive carotid sinus syndrome (HCSS) were investigated by continuous wave (CW) Doppler ultrasonography and high-resolution real-time B-scan. Using these non-invasive tests, the functional impact of luminal stenosis and the morphological changes resulting from arteriosclerotic deformities could be established. Significant differences were found in comparison with a reference group of 199 patients with a high risk of arteriosclerosis. In the HCSS group, 5 patients had a stenosis of more than 50% at the origin of the internal carotid artery on both sides, or on one side in combination with large plaques or a complete occlusion on the contralateral side. Seventy-five per cent of patients in the HCSS group, as compared to only 23.5% of the control group, had effective arteriosclerotic changes in the carotid bifurcation on both sides; 4 patients had such changes only unilaterally. Marked additional bilateral arteriosclerotic depositions were detected in the common carotid arteries of 17 patients (47.2%). In 5 patients no arteriosclerotic lesions were detectable in the carotid bifurcations, but marked changes were found in both common carotid arteries. These data indicate that bilateral arteriosclerotic changes in the carotid bifurcations and/or the common carotid arteries represent an important pathophysiological factor for the development of an HCSS.

Aged↗
PubMed1985

Monitoring of antifibrinolytic treatment in subarachnoid hemorrhage.

21 patients (aged 28-81 years) with recent subarachnoid hemorrhage (10 saccular aneurysms, 3 arteriovenous angiomas, 8 normal angiograms) were continuously infused with tranexamic acid at a dosage of 5 g daily for up to 14 days. Therapy was surveyed by daily measurement of the available plasminogen activity (aPl) with the chromogenic substrate S-2251 and by a modified bioassay, whereby the concentration of tranexamic acid was determined thrombelastographically and expressed as antifibrinolytic equivalent. In addition, a battery of blood coagulation tests was performed daily. 5 patients died, 1 after postoperative stroke, 3 as a result of general complications during intensive care treatment, but only 1 due to rebleeding. 4 patients were successfully operated during the first week, 1 patient after 2 weeks. aPl fell from 99.2% (SEM 3.0%, n = 21) before treatment to 72.9% (SEM 3.5%, n = 21) after 24 h and to the therapeutic level between 50 and 60% from day 2 on. The mean steady state of the antifibrinolytic equivalent corresponded to about 150 micrograms/ml of tranexamic acid during infusion. Intra- and interindividual changes were relatively small for aPl, when compared with the antifibrinolytic equivalent measured by the bioassay. In 2 elderly patients tranexamic acid infusion had to be terminated because of clinical and laboratory signs of disseminated intravascular coagulation, whereby aPl fell below the therapeutic range, elucidating that this method is a sensitive indicator for a hypercoagulable state and useful for the surveillance of therapy with antifibrinoltic agents.

Adult↗
PubMed1985

Sodium transport and red cell deformability.

Inhibition of the Na-K pump by a circulating factor is thought to be of importance in the pathophysiology of essential hypertension. We tested the correlation between an inhibition of the Na-K pump by digoxin and the deformability of red blood cells (RBC) both in vitro and in vivo. Erythrocytes were incubated with digoxin (0-1.3 mumol/l) for 1 h at 37 degrees C. Highest concentration of digoxin (0.13 and 1.3 mumol/l) significantly diminished Na-K pump activity, measured by uptake of 86rubidium (Rb). There was a parallel decrease in red cell filtrability. In nine healthy volunteers, intake of digoxin (0.2 mg b.i.d.) over a 5-day period did not alter red cell deformability and uptake of 86Rb. Taken together, inhibition of the Na-K pump in vitro correlates with a reduced red cell deformability. However, this occurs at a toxic dosis of digoxin.

Adult↗
PubMed1985

Haemorheology in adolescent hypertensives.

Fifty-three untreated borderline hypertensives and 73 normotensives were randomly selected from 1342 adolescents (age range 23-27 years) who were examined in 1975, 1976 and 1980 in an epidemiological study. Blood pressure was 127.2 +/- 1.0/79.0 +/- 0.8 mmHg in normotensives and 147.2 +/- 1.6/93.7 +/- 1.1 mmHg in hypertensives (P < 0.001). Erythrocyte deformability was measured with a positive pressure filter system (pore diameter 5 microns) at 37 degrees C. Erythrocyte deformability was significantly increased in hypertensives with a value of 1.77 +/- 0.05, compared with 1.64 +/- 0.04 in normotensives (P < 0.05). No difference in apparent whole blood viscosity, haematocrit and plasma fibrinogen was measurable between the groups. Although plasma noradrenaline and adrenaline concentration at rest and after 3 min standing were not different, excretion of urinary catecholamines was significantly elevated in hypertensives with 155.0 +/- 3.3 micrograms/24 h (normotensives: 100.7 +/- 5.3 micrograms/24 h; P < 0.001).

Adolescent↗
PubMed1984

Prolonged infusion of prostacyclin in patients with advanced stages of peripheral vascular disease: a placebo-controlled cross-over study.

Twelve patients (age 33-77 years, mean age 68.4 years) with peripheral vascular disease (PVD) stage III-IV received continuous intravenous infusions of 5 ng prostacyclin (PGI2)/kg/min and physiological saline for 7 days. The administration was randomized and double-blind with an interval of 7 days between the infusions. During PGI2 infusion systolic blood pressure fell significantly from 147.8 +/- 4.8 mm Hg to 140.6 +/- 4.0 mm Hg (P less than 0.01) and returned to 144.5 +/- 4.9 mm Hg post infusion. Transcutaneous pO2 (tcpO2) measured on the instep of the affected limb increased significantly by 8.9 +/- 3.8 Torr during PGI2 infusion and remained elevated during the subsequent week. A significant reduction of pain was observed from the 5th day of PGI2 infusion, lasting for at least the following observation period. Platelet cAMP increased from 18.8 +/- 1.5 pmol/10(8) platelets to 24.7 +/- 1.6 pmol/10(8) platelets on the 3rd day of PGI2 infusion (P less than 0.01). Spontaneous platelet aggregation was also significantly reduced during PGI2 infusion. However, 7 days after the infusion thromboxane B2 (TXB2) in plasma and spontaneous platelet aggregation significantly increased in comparison with the preinfusion values, indicating a rebound phenomenon. The clinical outcome was favorable in 9 of 12 patients, was unchanged in two patients, while progressing to limb amputation in one patient.

Adult↗
PubMed1984

Effect of haemodynamic changes during rapid atrial pacing on determination of sinus node recovery time.

Arterial blood pressure was continuously monitored during rapid atrial pacing in 31 patients with different types of heart disease to determine sinus node recovery time and corrected sinus node recovery time. Pacing was initiated at 70 beats/min and increased stepwise to 160 beats/min. One to one atrioventricular conduction was maintained throughout the one minute stimulation period. Blood pressure fell initially during at least one stimulation period in 21 of our patients and at pacing rates up to 130 beats/min in 18. Once blood pressure had fallen during overdrive pacing maximal sinus node recovery time and maximal corrected sinus node recovery time could not be prolonged by increasing the pacing rate. Sinus node recovery time and corrected sinus node recovery time during the pacing induced fall in blood pressure was significantly shorter than those during stimulation runs with constant blood pressure. No pacing induced fall in blood pressure and no relation between changes in blood pressure and sinus node recovery time were evident in 10 of the 31 patients. Sinus node recovery time is therefore influenced by alterations in autonomic tone due to pacing induced haemodynamic changes.

Aged↗