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Biomedical subjects

G Nollert

Publications and source records attributed to G Nollert.

46 records · Page 3Linked to original sources
PubMed1995

Use of the internal mammary artery as a graft in emergency coronary artery bypass grafting after failed PTCA.

The use of the internal mammary artery (IMA) is recommended in elective aorto-coronary bypass grafting (CABG) because of favourable long-term patency results. In emergency CABG many surgeons prefer revascularization only with venous grafts due to the shorter operation time and higher initial flow rates of this type of graft. We investigated whether use of the IMA influences operative and mid-term results of emergency CABG after failed percutaneous transluminal coronary angioplasty (PTCA). From January 1990, to March, 1993, 56 emergency CABGs were performed in patients from 7 different cardiological centres where PTCA had failed. In 23 patients (Group A), the IMA was used as a bypass graft. In most of these patients the left IMA was anastomosed with the left anterior descending artery (n = 19). In one case both IMAs were used as bypass grafts. Venous grafts only were applied in 33 patients (Group B). Due to preparation of the IMA, aortic cross-clamp and bypass times were approximately 15 mins longer in Group A patients, although there was no significant difference in the number of grafts (1.7 +/- 0.8 in Group A vs. 1.5 +/- 0.7 in Group B). All patients of Groups A and B underwent echocardiographical investigations 14.6 +/- 8.2 months postoperatively. The overall mortality in Group A was 13% (n = 3) compared to 9% (n = 3) in Group B (p = 0.58). Significant predictors for death were age 65 years and over, diabetes mellitus, dilatation of the RCX and stenoses unfavourable for PTCA.(ABSTRACT TRUNCATED AT 250 WORDS)

Angioplasty, Balloon, Coronary↗
PubMed1994

Comparison of UW versus HTK solution for myocardial protection in heart transplantation.

In order to evaluate the protective effect of University of Wisconsin (UW) solution in heart transplantation, a retrospective comparative study with histidine-tryptophane-ketoglutarate (HTK) solution was initiated. In group I, we included 160 patients with HTK preservation, while group II consisted of 50 patients who had their transplant protected with UW solution. All patients received standard quadruple drug therapy for immunosuppression. The average ischaemic time of the donor hearts in group I was 142+/-44 min, ranging from 83 to 235 min. Acute immediate perioperative graft failure occurred in six cases (3.8%). Statistical analysis including the chi-square test, revealed a significant increase in the incidence of acute perioperative graft failure when compared with duration of ischaemic time (P < 0.01). Within the first 30 postoperative days, 24 patients died (15% early mortality). The same statistical correlation was evident between the incidence of early mortality and duration of graft ischaemic time. The 30-day and 6-month survival rates were 81% and 78%, respectively. The average ischemic time of the donor hearts in group II was 193+/-50 min ranging from 100 to 360 min, which was significantly longer in comparison with the group I (P < 0.05). Acute perioperative graft failure occurred once (2%); the patient was retransplanted successfully. Five patients died within the first 30 postoperative days (10% early mortality). There was no correlation between length of ischaemic time and incidence of acute graft failure or early mortality. The 30-day and 6-month survival rates were 90% and 88%, respectively and, thus, better when compared with group I. In both groups similar results were achieved with regard to postoperative NYHA status of the patients and incidence of cardiac arrhythmias. Myocardial preservation with HTK solution showed satisfying results as long as the ischaemic time did not exceed 4 h. The early functional results achieved with UW graft protection were excellent, even with ischaemic times longer than 4 h and not depending on lenght of ischaemic period.

Adenosine↗
PubMed1993

Myocardial preservation using HTK solution for heart transplantation. A multicenter study.

Bretschneider HTK solution is commonly used for myocardial preservation. In order to evaluate its protective effect for heart transplantation, a retrospective study was initiated in cooperation with Eurotransplant and five heart transplant centers. Seventy-six female and 524 male patients who underwent cardiac transplantations between 1981 and 1991 were included in this study. Using standardized questionnaires, donor and recipient laboratory data, immunosuppressive therapy and the preoperative, intraoperative and postoperative organ function were documented. The average ischemic time of the donor hearts was 160 min, ranging from 75 min-304 min. Immediate postoperative graft failure was observed in 25 transplantations (4.2%). Within the first 30 days 71 organs (11.8%) failed. Using the chi2-test, a statistically significant increase of acute graft failure and early mortality was evident when they were correlated with the length of ischemic time (P = 0.01). In addition, a higher incidence of early graft failure was observed when the perfusion volume was less than 1500 ml. The 1- and 5-year survival rates were 72% and 63%, respectively. Organ preservation with HTK shows good results as long as the ischemic time does not exceed 4 h. The possibility that an increased perfusion volume allows longer ischemic times cannot be excluded with this study.

Cardioplegic Solutions↗
PubMed1993

Effects of recombinant human erythropoietin on autologous blood donation before open heart surgery.

We studied the effects of four different doses of recombinant human erythropoietin (rhEPO) on the amount of preoperative autologous blood donation. 43 patients prior to open heart surgery were randomized into 5 groups (100, 200, 400, 800 U/kg rhEPO i.v. or placebo) and treated twice weekly over a period of 4 weeks. Autologous blood was taken at a hemoglobin of 13 g/dl and a hematocrit of 34% respectively. Application of low-dose rhEPO (100 and 200 U/kg) did not increase the amount of autologous blood donated, only 400 and 800 U/kg produced a significant increase by 27% and 39% respectively (p < 0.01) In addition RBC showed a reduced decline of hemoglobin level (p < 0.01). Reticulocytes increased by 2.5 times the baseline in the placebo and treatment groups up to 200 U/kg. Again, only 400 and 800 U/kg produced a significantly higher increase of 3.2 and 3.6 times respectively (p < 0.05 and p < 0.01). Although iron was supplied orally, ferritin levels declined in all groups whereas serum iron and transferrin levels remained unchanged. No influence could be detected on WBC, thrombocyte count, or arterial blood pressure. Mild and reversible side effects were observed in 8 patients (19%). Perioperatively 34 patients (81%) received exclusively autologous blood, only 8 patients (19%) needed additional homologous blood transfusions. Administration of high-dosed rhEPO (400-800 U/kg) seems to be an effective treatment with only slight side effects for increasing erythropoiesis during autologous blood donation.

Adolescent↗
PubMed1993

Long-term results of pacemaker therapy after orthotopic heart transplantation.

The objectives of this study were to identify: (1) the indications for pacemaker implantation; (2) the long-term survival; (3) the percentage of bradyarrhythmias below 50 beats/min persisting for more than 3 months; and (4) the variables predicting persistent bradyarrhythmias following orthotopic heart transplantations. During the recent decade (August 1, 1981 through December 31, 1991), 237 patients underwent orthotopic heart transplantation at our institution. Twenty-six recipients (11%) showed evidence of a symptomatic bradyarrhythmia due to sinus node dysfunction (n = 25) or complete heart block (n = 1), which required insertion of a permanent pacing device. During a mean follow-up period of 17.2 months (range 3 to 57 months), five patients (19%) died and one was lost to follow-up. Actuarial survival at 1 and 4 years were 81% and 65%, respectively, as compared to 79% and 69%, respectively, in patients without permanent pacemakers. Holter monitoring after 3 months (n = 25) and 1 year (n = 14) showed a spontaneous heart rate below 50 beats/min in six (24%) and three patients (18%), respectively. None of the tested variables predicted the necessity of initial pacemaker implantation. However, in patients requiring permanent pacing for a period longer than 3 months, ischemic time of the donor heart was found to be significantly longer as compared to the other patients (221 +/- 76 min vs 137 +/- 91 min, p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMedDate not supplied

Registration of thoracic electrical bioimpedance for early diagnosis of rejection after heart transplantation.

In this study, registration of thoracic electrical bioimpedance was used for early detection of acute rejection after heart transplantation. Thirty-five heart transplant recipients were monitored by registration of thoracic electrical bioimpedance signals during the immediate postoperative period and during the outpatient follow-up. At the same time, endomyocardial biopsy specimens were taken. In addition to cardiac stroke volume index and ejection fraction, the acceleration index (seconds -2) was calculated. This acceleration index describes the acceleration of blood volume and represents a function parameter of the myocardial inotropy. Seventeen acute rejection episodes were diagnosed during the follow-up period. The average acceleration index value during the 17 rejection episodes was 92.5 +/- 11.7 sec-2 and thus significantly lower when compared with the nonrejection levels (p < 0.05). The acceleration index values decreased during acute rejections by an average of 36.4 +/- 19.3 sec-2 (28%). The sensitivity of this diagnostic parameter in the examined patients was 71%, and the specificity was 100%. Thus registration of thoracic electrical bioimpedance and calculation of the acceleration index represents a quick and noninvasive monitoring technique and can ideally be used in the outpatient clinic as a supplement to invasive endomyocardial biopsies.

Adult↗
PubMedDate not supplied

The influence of gastrointestinal agents on resorption and metabolism of cyclosporine after heart transplantation: experimental and clinical results.

The clinical effectiveness of cyclosporine is limited by changes in resorption and metabolism of cyclosporine and by possible drug interactions. This study examined the influence of five gastrointestinal agents on duration and resorption of cyclosporine and dosage/level relations: cimetidine, famotidine, pirenzepine, aluminum hydroxide, and omeprazole. These gastrointestinal agents were studied in 64 rat experiments, in which the impact of each single drug and of drug combinations on cyclosporine resorption and metabolism was tested. A standardized dosage of cyclosporine was given orally, and the duration was calculated for the maximum whole blood level of cyclosporine to be achieved; the dosage/level quotient was calculated. Cimetidine, famotidine, pirenzepine, and combination treatment prolonged duration of cyclosporine resorption. Furthermore, cimetidine, famotidine, and omeprazole lowered the dosage/level quotient, thus leading to higher cyclosporine levels with the same dosage; pirenzepine increased the dosage/level quotient. For clinical comparison, 163 heart transplant patients who had received standard triple-drug immunosuppressive therapy were analyzed. The time interval until a therapeutic cyclosporine level was achieved and the dosage/level quotient were once again calculated. Similar to the results in the animal experiments, cimetidine and famotidine significantly delayed the resorption of cyclosporine; cimetidine, famotidine, and omeprazole lowered the cyclosporine dosage/level quotient, thus leading to higher cyclosporine levels with the same dosage. Aluminum hydroxide did not lead to any changes in the resorption or metabolism of cyclosporine. Most examined gastrointestinal agents, and particularly H2-blocking drugs, led to significant prolongation of cyclosporine resorption and cyclosporine level alterations. The initial prolongation of cyclosporine resorption was successfully avoided by intravenous administration of cyclosporine for the first 4 postoperative days in 40 consecutive patients.

Absorption↗