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Biomedical subjects

G Kober

Publications and source records attributed to G Kober.

At least 19 recordsLinked to original sources
PubMed2001

Influence of right ventricular pre- and afterload on right ventricular ejection fraction and preload recruitable stroke work relation.

When right ventricular (RV) afterload is abnormally increased, it correlates inversely with right ventricular ejection fraction (RVEF). We tested, whether this would be different with normal afterload. Additionally, we investigated whether previous studies on the slope of RV preload recruitable stroke work (SW) relation, which used rather non-physiological measures to change RV preload, could be transferred to more physiological loading conditions. RV volumes were determined by thermodilution in 16 patients with stable coronary artery disease and normal pulmonary artery pressure (PAP) at rest. Pre- and afterload were varied by body posture, nitroglycerin (NTG) application and by exercise at different body positions. At rest, the change from recumbent to sitting position decreased PAP, cardiac index (Ci), RV diastolic and systolic volumes, and RVEF. Additionally, mean pulmonary artery pressure (MPAP) correlated positively with both RVEF and cardiac index. After correction for mathematical coupling, the RV preload recruitable SW relation was: right ventricular stroke work index (RVSWi) (103 erg m-2)= 8.1 x (RV end-diastolic volume index -4.9), with n=96, r=0.57, P< or =0.001. Exercise abolished this correlation and led to an inverse correlation between RV end-systolic volume (ESV) and RVSW. In conclusion, (i) RVEF correlates positively with RV afterload when afterload varies within normal range; (ii) the slope of the RV preload recruitable SW relation, which is obtained at steady state under normal loading conditions, is substantially flatter than previously described for dynamic changes of RV preload. With increasing afterload, preload loses its determining effect on RV performance, while afterload becomes more important. This puts earlier assumptions of an afterload independent RV preload recruitable SW relation into question.

Aged↗
PubMed1999

[Magnesium excretion in urine is not a marker of magnesium deficiency. Reliability of an oral magnesium administration test].

BACKGROUND: Serum magnesium analysis does not reflect body content of magnesium. So substitution is based on empirical maneuvers. PATIENTS AND METHOD: In a study on 44 patients urinary magnesium excretion was analyzed before and after oral magnesium substitution (40 mval). The provable hypothesis was the estimation that patients in magnesium deficiency under chronical diuretic treatment (n = 11) would have a lower magnesium excretion than patients of the control group (n = 10). Further analysis was done with patients after orthotopic cardiac transplantation (n = 12) and those suffering from coronary heart disease (n = 11). RESULT: After oral administration of magnesium in all 4 groups there was a rise in blood levels, only significant in the patient group under chronic diuretic treatment. Urinary magnesium excretion, however, showed no significant differences. Patients after cardiac transplantation had the lowest rise in urinary magnesium excretion. CONCLUSION: There was no clear differentiation by means of this oral magnesium substitution test. Magnesium excretion even after oral substitution is of no value to analyze magnesium deficiency.

Administration, Oral↗
PubMed1999

Sulfonylureas and ischaemic preconditioning; a double-blind, placebo-controlled evaluation of glimepiride and glibenclamide.

AIMS: Glimepiride is a new sulfonylurea for diabetes treatment which is supposed to impact less on extra-pancreatic ATP-dependent K+ channels than the conventional drug glibenclamide. This study was performed to evaluate whether this results in a better maintenance of ATP-dependent K+ channel mediated ischaemic myocardial preconditioning. METHODS AND RESULTS: In a double-blind placebo-controlled study the period of total coronary occlusion during balloon angioplasty of high grade coronary artery stenoses was used as a model to compare the effects of both drugs. Quantification of myocardial ischaemia was achieved by recording the intracoronary ECG and the time to the occurrence of angina during vessel occlusion. All patients underwent three dilatations. The first dilatation (dilatation 1) served to determine the severity of ischaemia during vessel occlusion. During dilatation 2, baseline values were recorded. Thereafter, glimepiride (15 patients: 1.162 mg), glibenclamide (15 patients: 2.54 mg) or placebo (15 patients) were intravenously administered over 12 min. Dilatation 3 started 10 min after the beginning of the drug administration. Mean ST segment shifts in the placebo group decreased by 35% (dilatation 2: 0.23; dilatation 3:0.15 mV; CI -0.55 to 0.00 mV; P=0.049). A similar reduction also occurred in the glimepiride group, in which repetitive balloon occlusion led to a 34% reduction (dilatation 2: 0.35; dilatation 3: 0.23 mV; CI -0.21 to -0.02 mV; P=0.01). There was little influence however, on mean ST segment shifts in the glibenclamide group (dilatation 2 and dilatation 3: 0.24 mV; CI -0.10 to 0.25 mV; P=0.34). Accordingly, time to angina during balloon occlusion slightly increased (by 30%) in the placebo group (dilatation 2: 37 s; dilatation 3: 48 s; CI 0.0 to 15.0 s; P=0.16); increased by 13% in the glimepiride group (dilatation 2: 40 s; dilatation 3: 45 s; CI 0.0 to 14.0 s; P=0023); and remained unchanged in the glibenclamide group (dilatation 2 and dilatation 3: 30 s; CI -7.5 to 7.5 s; P=0.67). CONCLUSION: These results show that glimepiride maintains myocardial preconditioning, while glibenclamide might be able to prevent it.

Adult↗
PubMed1998

[Full working capacity instead of threatened retirement. Thrombendarterectomy in chronic thromboembolic pulmonary hypertension].

HISTORY AND CLINICAL FINDINGS: A 56-year-old man in marked right heart failure (stage III-IV of the New York Heart Association classification) and severe pulmonary hypertension was admitted to a rehabilitation clinic for therapeutic and social-medical assessment. On physical examination the important features were markedly distended neck veins, tachycardia at rest (90/min), a loud 2nd pulmonary sound and dyspnea. INVESTIGATIONS AND DIAGNOSIS: Non-invasive tests (ECG, echocardiography, abdominal ultrasound and lung functions) confirmed right heart failure; invasively obtained haemodynamic data indicated its severity. Selective pulmonary angiography defined the embolisation to be central and bilateral. TREATMENT AND COURSE: As intensive drug treatment and physiotherapy had failed to achieve significant improvement, operative removal of the bilateral central and some segmental pulmonary thrombi was performed and an inferior vena caval filter inserted. Immediately after operation the markedly elevated right-heart and pulmonary artery pressures fell markedly and there was dramatic improvement in the patient's general condition and in his physical capacity. Angiography demonstrated largely normal pulmonary perfusion. Instead of the anticipated retirement, the patient was discharged on anticoagulants, in the expectation of a return to full-time work. CONCLUSION: With pulmonary thrombendarterectomy severe chronic thromboembolic pulmonary hypertension may well be treated.

Echocardiography↗
PubMed1997

Chronic coronary occlusions: age, morphology and chance of reopening.

In chronic coronary occlusions the chance of successful reopening by angioplasty can be judged from the age of the occlusion. Often, however, time since occlusion cannot be accurately assessed. Therefore we determined whether the chance of reopening can be predicted from angiographic morphology. In cineangiograms from 60 consecutive patients with chronic coronary occlusions morphological details in at least two projections were evaluated in relation to the rate of success and the estimated age of occlusion. Morphological features associated with a higher rate of success (type A) were a clearcut proximal stump, absence of side branches at the site of occlusion, absence of bridging collaterals, and only slight filling of the distal part of the vessel. Features associated with a low success rate (type B) were absence of proximal stump, side branches at the site of occlusion, bridging collaterals, and rapid high-contrast filling of the distal part of the vessel. 48/60 (80%) of occlusions could be classified as type A or type B. The success rate was 17/21 (81%) in type A versus 5/27 (18.5%) in type B (P < 0.0002). The estimated age of type B occlusions was higher than that of type A medians 8 and 4 months (P < 0.002). Thus in chronic coronary occlusions the likelihood of successful reopening can be judged in many patients from morphological features.

Angioplasty, Balloon, Coronary↗
PubMed1996

[Alternative techniques in coronary intervention--a new differential therapy?].

Alternative coronary angioplasty techniques have not been applied as often as initially supposed. Due to the favorable success rates, complication rates and costs, balloon angioplasty is still the gold standard and primary intervention procedure. Beyond that, in randomized studies recurrence rates were shown mostly higher with newer techniques. Thus alternative techniques are recommendable only when balloon angioplasty is unsuccessfull or when a failure is to be expected. Today, some niches for alternative techniques can be defined, although they have to be confirmed in further randomized studies, particularly since these techniques usually require a final balloon dilatation and can give rise to new complications.

Angioplasty, Balloon, Coronary↗
PubMed1995

[Telemetry during swimming in risk evaluation of heart patients in rehabilitation].

Swimming differs from other forms of exercise due to its additional hydrostatic and thermal burden. It was investigated whether additional pathologic findings in comparison to history and standard exercise tests can be obtained by holter monitoring during swimming. Symptoms and exercise electrocardiogram were compared with the holter ECG during swimming in 125 patients divided into 3 groups with different diagnoses and severity of cardiac diseases. In a considerable percentage of patients ischemic changes and severe rhythm disturbances were found only during swimming with further diagnostic and therapeutic consequences, though patients with moderate and severe angina and with significant ischemic signs in the exercise test were excluded and mainly patients with slight or absent symptoms were evaluated predominantly. Thus, since swimming is a favorite leisure-time occupation also in patients with diseases of heart and circulation, holter monitoring during swimming is of diagnostic importance in the rehabilitation of these patients.

Adult↗
PubMed1995

Chronic angiotensin-converting enzyme inhibition may improve sodium excretion in cardiac transplant hypertension.

Cyclosporine-associated hypertension (CAH) may be mediated in part by sodium and volume retention. To investigate this issue, we studied the effects of a calcium antagonist, nitrendipine (NIT, 10-20 mg b.i.d.), and a converting enzyme inhibitor, lisinopril (LIS, 10-20 mg o.d.), on blood pressure (office BP, 24 hr ambulatory BP), excretion of an acute sodium load (200 mmol/2 hr i.v.), glomerular filtration rate (insulin clearance), cumulative dopamine excretion, plasma atrial natriuretic peptide (ANP), and endothelin excretion in 8 patients with CAH after cardiac transplantation in a double-blind, randomized, crossover trial for 6 weeks. Five patients received a diuretic during the trial at a constant dose. Office diastolic BP (DBP) decreased significantly with LIS from 97 +/- 6 to 87 +/- 9 mmHg and with NIT from 96 +/- 7 to 92 +/- 12 mmHg. Ambulatory 24 hr DBP decreased significantly from 96 +/- 7 mmHg to 86 +/- 10 mmHg (LIS) and to 84 +/- 11 mmHg (NIT). Ambulatory DBP during the day was lowered significantly from 98 +/- 11 mmHg to 87 +/- 10 mmHg (LIS) and to 88 +/- 9 mmHg (NIT) and during the night from 95 +/- 9 mmHg to 86 +/- 8 mmHg (LIS) and to 79 +/- 7 mmHg (NIT). Cumulative sodium excretion 6 hr after an acute sodium load increased to 52 +/- 39 mmol (placebo), 96 +/- 44 mmol (LIS, P < 0.05 vs. placebo), and 71 +/- 34 mmol (NIT). Glomerular filtration rate, cumulative dopamine excretion, ANP, and endothelin excretion did not differ between either treatment group. We conclude, that: (1) both drugs were similar in lowering office BP and during the day, but NIT tended to be more effective during the night; and (2) cumulative sodium excretion during LIS was significantly increased compared with placebo. There was a similar trend during NIT also. Therefore, it is possible that chronic angiotensin-converting enzyme inhibition and possibly calcium antagonists might improve the sodium-retaining state in CAH independent of differences in blood pressure, ANP, dopamine, or renal function.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1995

[Color Doppler-guided compression of pseudoaneurysms after arterial puncture. Early and late results].

Sixteen pseudoaneurysms occurred after 1796 femoral arterial punctures for diagnostic coronary angiography and/or angioplasty, performed between 1. 1. 1993 and 25. 3. 1994. One additional patient with pseudoaneurysm had undergone a femoral arterial puncture at another hospital. Primary colour Doppler-directed compression of the pseudoaneurysm (15-minute compression followed by 10-minute compressions, as needed) was successful in 16 patients. There was one recurrence, after five days, which was successfully and lastingly treated by another compression. Primary thrombosing by compression of the pseudoaneurysm failed in only one patient, but after spontaneous thrombosis achieved by a compression bandage no flow was demonstrable on the following day. Clinical examination and/or colour Doppler sonography was performed on all patients a mean of 84 days (5 days to 6 months) after successful treatment: no recurrence was recorded. There were no significant early or late complications. These data indicate that colour Doppler-monitored compression of femoral-artery pseudoaneurysm can be considered the treatment of choice, with few exceptions, for this not rare complication of arterial catheterization.

Aneurysm, False↗
PubMed1994

Risk of endomyocardial biopsy in immunosuppressed patients after cardiac transplantation.

OBJECTIVES: Central venous puncture is required for endomyocardial biopsy to identify rejection after cardiac transplantation. We evaluated our use of the Seldinger technique to determine the safety of this invasive method. METHODS: In 42 immunosuppressed patients central venous puncture was performed after cardiac transplantation using the Seldinger technique for right heart biopsy. Together with physical examinations, chest X-ray and cardiac ultrasonography were performed during the inhospital follow-up. Outpatient follow-up continues and all reported adverse effects were evaluated by the attending cardiologist. RESULTS: There were a total of 620 central venous punctures, most via the right internal jugular vein (77.9%). The planned puncture could not be performed in 3.2% of the cases and an alternative site was used. The femoral approach was associated with the longest radiation time. No severe adverse effects were observed and no complications (infection, large haematoma, pneumothorax, severe rhythm disorders) were recorded. CONCLUSION: Even in immunosuppressed patients frequently requiring central venous puncture, right heart endomyocardial biopsy can be safely performed to evaluate rejection.

Adult↗
PubMed1994

Recoil following Wiktor stent implantation for restenotic lesions of coronary arteries.

The purpose of this study was to determine acute recoil of the vessel wall immediately after Wiktor stent implantation in native coronary arteries of 77 consecutive patients and to assess whether there was compression or "late recoil" of the stent itself at long-term follow-up. Furthermore, the relationship between recoil and a number of clinical, angiographic, and procedural variables was studied in addition to the relation between acute recoil renarrowing or restenosis was assessed. All angiograms were analyzed with the Cardiovascular Angiography Analysis System using automated edge detection. Acute recoil was defined by the difference between the mean diameter of the fully expanded balloon on which the stent was mounted and the mean diameter of the stented segment. Late recoil was calculated by comparing the mean diameter of the stent itself immediately after implantation and at follow-up without opacification of the vessel. Acute recoil amounted to 0.25 +/- 0.32 mm or 8.2%. Multivariate analysis identified sex (coefficient = -0.20, p = 0.04) and stent/artery ratio (coefficient = 0.99, p = 0.0001) as the only independent predictors of acute recoil. "Late recoil" of the stent itself was not observed. The overall difference between the mean diameter of the stent itself immediately after implantation and at follow-up was -0.15 +/- 0.33 mm, suggesting an overall increase in diameter of 5.0%. There was no relation between acute recoil and late restenosis. On the contrary, there was a trend towards a greater degree of recoil in patients without restenosis. Moreover, linear regression analysis disclosed a weak but negative correlation between acute recoil and a loss in minimal luminal diameter (coefficient: -0.55, p = 0.04). The Wiktor stent effectively scaffolds the instrumented vessel. Only a minimal amount of acute recoil was noted, which did not contribute to late luminal renarrowing or restenosis. In addition, no late compression of the stent itself was observed. These data suggest that tissue ingrowth into the lumen of the stented segment is the main cause of late luminal renarrowing after stent implantation.

Aged↗