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R Körfer

Publications and source records attributed to R Körfer.

At least 37 records · Page 2Linked to original sources
PubMed2002

The heater-cooler unit--a conceivable source of infection.

Even drinking water is contaminated with pathogenic microorganisms. This does not necessarily pose a risk for healthy individuals, but it may result in serious consequences in people with impaired immune systems. This is particularly valid if drinking water is used for medical purposes. The heater-cooler unit (HCU) connected to heat exchangers or blankets by tubing, the connection is closed water circuit that contains microorganisms and algae. While connecting the tubing to the heat exchanger, spilling of water cannot be avoided. Microbiological examinations showed that germs and particles pollute the units. Exposure to the patient and the OR equipment has the potential to increase the risk of infection should the HCU water come in contact with the patient. As a result of the high incidence of particle and algae in the HCU, malfunction occurs. Sampling shows >1000/mL CFU (colony forming units) at 36 degrees C and 55/mL CFU at 20 degrees C on average. The specific findings include Pseudomonas and Legionella. Disinfecting HCU is very difficult. Often HCUs do not provide any technology to reduce bacterial or other contamination. The instructions for use of oxygenators often exclude the use of disinfectants. Maintenance instructions for the HCU advocate the use of disinfectants that carry the risk of oxygenator damage and of heat exchanger leakage. The effect of chemical disinfectants and heat exchanger membranes have not been examined, they may impair heat exchanger permeability and function. As an alternative to chemical and thermal disinfection, we used the alternative method of filtration. Using a membrane filter element, we noticed a decreasing number of CFUs from 55 to sterile conditions at 20 degrees C and from >1000 CFUs to 100 CFUs at 36 degrees C (Figure 1). In addition, we noticed a removal of other particles and algae. In conclusion, we have demonstrated a technique that is simple to implement and effectively reduces the microbiological load of the water in the heater-cooler unit.

Disinfection↗
PubMed2001

Successful use of cardiac allograft from serotonin antagonist intoxication.

BACKGROUND: Compromised organ donors are generally not accepted for heart transplantation (HT) despite the increasing number of critically ill patients on the waiting lists. By extending the donor criteria to include certain cases of intoxication, the organ shortage may be reduced. METHODS: The case of a successful orthotopic HT with an allograft from a donor poisoned by antidepressant overdose is presented. RESULTS: Early graft function was satisfactory with anteroseptal dyskinesis and an ejection fraction of 75% on echocardiography. The cardiac allograft recipient suffered some postoperative complications including gastrointestinal problems. The following period was up to now uneventful. Discharge from the intensive care unit was after 4 days. In-hospital stay was prolonged at 26 days. CONCLUSIONS: Because of limited myocardial toxicity, donor hearts from certain victims of antidepressant intoxication may be safely used for HT. Existing cardiac organ donor criteria must be reevaluated to maximise the available organ pool.

Adult↗
PubMed2001

Differential indication for mechanical circulatory support following heart transplantation.

PURPOSE: We describe our experience with ventricular assist devices (VAD) in patients with cardiogenic shock refractory to pharmacological therapy and support using intraaortic balloon pump after cardiac transplantation. PATIENTS: Between July 1987 and August 1997, 848 patients underwent cardiac transplantation in our hospital. INTERVENTIONS: Fifteen patients (1.8%) needed mechanical circulatory support for refractory cardiac failure due to right heart failure (six patients), primary graft failure (three patients), and acute rejection (six patients). Three pump systems were used: Biomedicus Centrifugal Pump, Abiomed BVS 500, and Thoratec VAD. The choice of system depended on the indication and quality of each device. Seven patients (47%) could be weaned from the mechanical circulatory support (MCS) system and three patients (20%) are long-term survivors. RESULTS: All 15 patients developed at least one serious complication, such as multiorgan failure (MOF), liver failure, acute renal failure or sepsis. Twenty-five per cent had severe bleeding and 13% had neurological complication. Mortality was due mostly to MOF, MOF and sepsis or sepsis. The survivors had a CI greater than 2.2 l.min.m2, total bilirubin less than 1.0 U/1, and did not undergo resuscitation. CONCLUSIONS: Heart failure after cardiac transplantation severe enough to require MCS is currently associated with several major complications and high mortality (80%).

Adult↗
PubMed2001

Pseudoaneurysm after heart transplantation with history of LVAD driveline infection.

An infective complication of the aorta is a potential cause of early and late mortality after heart transplantation. We report the case of a 21-year-old male cardiac transplant patient in whom a pseudoaneurysm of the recipient site of ascending aorta coincided with the site of the outflow prosthesis of a preexisting left ventricular assist device; this condition developed 9 months after transplantation.

Adult↗
PubMed2001

Device and patient management in a bridge-to-transplant setting.

BACKGROUND: A variety of sophisticated devices have been developed for mechanical circulatory support in patients bridged to cardiac transplantation. Based on 13 years' experience, we have developed specific protocols for patient selection and management for different devices. METHODS: The principal systems applied in the bridge-to-transplant cohort are the Thoratec ventricular assist device (n = 144, mean duration of support 53 +/- 57 days), the Novacor left ventricular assist system (LVAS) (n = 85, mean duration of support 154 +/- 15 days), and the HeartMate LVAS (n = 54, mean duration of support 143 +/- 142 days). The Thoratec device is used for biventricular assistance or if the duration of support is expected to be less than 6 months. For long-term support, either the Novacor or HeartMate LVAS are preferred. RESULTS: Despite careful postoperative patient management, this group of patients is prone to a variety of complications. Bleeding occurred in 22% to 35%, right heart failure in 15% to 26%, neurologic disorders in 7% to 28%, infection in 7% to 30%, and liver failure in 11% to 20% of patients. Complications varied with the device applied and the patient's preoperative condition. A total of 73 patients were discharged from hospital for a mean period of 184 days; this cumulative experience amounted to 37.5 patient-years. CONCLUSIONS: The Novacor and the HeartMate systems offer the additional possibility of discharging patients during support if they fulfill certain criteria. The main reasons for rehospitalization were thromboembolic and infectious complications.

Adult↗
PubMed2001

International normalized ratio self-management after mechanical heart valve replacement: is an early start advantageous?

BACKGROUND: Severe thromboembolic and hemorrhagic complications after mechanical heart valve replacement essentially depend on the intensity of oral anticoagulation and the fluctuation of individual international normalized ratio (INR) values. METHODS: After heart valve replacement with Medtronic Hall, St. Jude Medical, and CarboMedics implants, patients were randomly divided into two groups, one controlling INR values at home, the other being monitored by family practitioners. RESULTS: Almost 80% of the INR values recorded by patients at home were within the stipulated therapeutic range, INR 2.5 to 4.5, compared with just 62% of INR values recorded by family practitioners. The overall complication rate (hemorrhages and thromboembolic events) of the self-management group was significantly (p < 0.05) decreased compared with the conventional group. CONCLUSIONS: Through INR self-management, an improvement in the quality of ongoing oral anticoagulation could be shown. Starting this form of therapeutic control early after mechanical heart valve replacement appears to effect a further reduction in anticoagulant-induced complications.

Adult↗
PubMed2001

Midterm follow-up of patients discharged from hospital under left ventricular assistance.

BACKGROUND: Against the background of increasing demand for long-term mechanical circulatory support, discharging patients to their homes while on assist devices becomes more and more important. This report describes the midterm follow-up of 66 patients who were allowed to leave the hospital under left ventricular assist device (LVAD) support with Novacor or HeartMate systems. Between May 1994 and January 2000, 66 patients (9 women, 57 men, between 15 and 68 years old) under LVAD support fulfilled our criteria for being discharged home on the device. Intent to treat comprised bridging to transplantation in 59 patients, bridging to recovery in 5 patients, and alternative to transplantation in 2 patients. Forty-four patients received support with Novacor, 18 patients with the VE HeartMate, 2 patients with centrifugal pumps and Novacor, and 1 patient each with Novacor and Thoratec/Medos HIA-VAD. The mean out-of-hospital (OOH) follow-up period was 162 +/- 187 days, with a cumulative OOH experience of 30 patient years. Twenty-nine patients were not readmitted, and 37 patients were readmitted 54 times (23 patients were readmitted once, 11 patients twice, and 3 patients 3 times). The primary reasons for readmission included neurologic disorders and infection complications. At 229 days, 50% of all patients were free from readmission. The readmission rate was 1.8 patient/year. Sixteen patients died while on LVAD support (24%). Our midterm follow-up results show the safety and efficacy of this therapeutic option. Acceptable hospital readmission rates strongly support the future use of this technology as an alternative to transplantation in managing end-stage heart failure patients.

Adolescent↗
PubMed2001

The time course of natriuretic hormones as plasma markers of myocardial recovery in heart transplant candidates during ventricular assist device support reveals differences among device types.

BACKGROUND: The natriuretic hormones ANP and BNP are expressed differently in the myocardium. Both hormones have compensatory diuretic activity during heart failure. Mechanical stretch of the myocardial walls induces the expression of these hormones. In failing human myocardium, both ANP and BNP are transcribed in the ventricular myocardium in high amounts. We measured the plasma concentrations of ANP and BNP in patients supported by various ventricular assist devices (VADs) at various times. We analyzed the time courses of ANP and BNP to determine (1) the time scale of their down-regulation as a marker of putative myocardial recovery, (2) their steady-state levels under VAD support and (3) differences caused by various VAD devices. METHODS: We analyzed ANP and BNP using commercially available radioimmune assays. We analyzed the time courses of patients supported by Thoratec (THO) LVAD (n = 8), TCI Heartmate (TCI) (n = 6), Novacor (NOV) (n = 7), and Lionheart (LIO) (n = 3). RESULTS: Patients supported with NOV and some patients with TCI showed down-regulation of BNP to a steady-state level at 30 to 50 days, following a single exponential decay. In contrast, patients supported by THO or LIO did not reveal a determined time course of the natriuretic hormones. Only a few patients reached normal plasma values during VAD support. CONCLUSION: The time courses of ANP and BNP differ among VAD types because of construction and/or driving mode, which might be important when considering patients for weaning from VAD without heart transplant.

Adult↗
PubMed2001

Heparin-coated extracorporeal circulation with full and low dose heparinization: comparison of thrombin related coagulatory effects.

Thrombin related coagulatory effects of a heparin-coated cardiopulmonary bypass system combined with full and low dose systemic heparinization were investigated in a prospective, randomized study in coronary bypass surgery patients. One hundred nineteen patients were divided into 3 groups. Group A (n = 39) had a standard uncoated extracorporeal circulation (ECC) set, and systemic heparin was administered in an initial dose of 400 IU/kg body weight. During ECC activated clotting time (ACT) was maintained at > or =480 s. Group B (n = 42) had the same ECC set completely coated with low molecular weight heparin. Intravenous heparin was given in the same dose as in Group A, and ACT was kept at the same level. Group C (n = 38) had the same coated ECC set as Group B, but intravenous heparin was reduced to 150 IU/kg, and during ECC, ACT was set to be > or =240 s. The same ECC components were used in all 3 groups including roller pumps, coronary suction, and an open cardiotomy reservoir. Thrombin generation as indicated by F1/F2 was significantly elevated at an ECC duration >60 min if heparin-coated ECC combined with low dose systemic heparinization was employed. Complexed thrombin (TAT) was significantly elevated after administration of protamine. Release of D-dimers indicating fibrinolysis was not significantly different between groups. Signs of clinical thromboembolism, i.e., postoperative neurological deficit, occurred in 2 patients in Group A and 1 patient in Group C. We conclude that heparin-coated extracorporeal circulation combined with reduced systemic heparinization intraoperatively leads to significantly increased thrombin generation, but not to increased fibrinolysis.

Adult↗
PubMed2001

Clinical use of heparin-coated cardiopulmonary bypass in coronary artery bypass grafting.

Clinical handling, risk and benefit of a heparin-coated cardiopulmonary bypass system combined with reduced systemic heparinization in coronary bypass surgery was investigated in a prospective, randomized clinical study. 243 patients (Pts.) were divided into 3 groups: group A (n = 83) had a standard uncoated extracorporeal circulation (ECC) set, and systemic heparin was administered in an initial dose of 400 IE/kg body weight. During ECC activated clotting time (ACT) was kept > or = 480 sec. Group B (n = 77) had the same ECC set completely coated with low-molecular-weight heparin; i.v. heparin was given in the same dose as in group A, ACT was kept at the same level. Group C (n = 83) had the same coated ECC set as group B, but i.v. heparin was reduced to 150 IE/kg, and was set to be > or = 240 sec during ECC ACT. The same circulatory components were used in all 3 groups including roller pumps, coronary suction and an open cardiotomy reservoir. In the postoperative clinical course, recovery was not significantly different between groups, especially with respect to organ dysfunction; but there was significantly reduced postoperative bleeding where heparin-coated ECC and low-dose systemic heparinization were both used. This circulatory technique was also associated with a distinctly lower need for postoperative blood replacement. We conclude that heparin-coated extracorporeal circulation combined with either full-dose or reduced systemic heparinization can be used effectively with the same standard equipment and procedures as in uncoated technology. Combination with low-dose i.v. heparin leads to significantly decreased blood loss and less need for blood replacement.

Adult↗
PubMed2001

Right ventricular diastolic function in beta-thalassemia major: echocardiographic and clinical correlates.

BACKGROUND: Cardiac hemochromatosis remains the most frequent cause of death in beta-thalassemia major. Previous studies suggest an important right ventricular (RV) contribution to cardiac morbidity and mortality. Studies with Doppler echocardiography have shown contradictory results regarding left ventricular (LV) filling, whereas the RV filling characteristics have not been studied yet. We prospectively studied the pattern of RV filling and investigated echocardiographic and clinical correlates during baseline and follow-up examinations in patients with beta-thalassemia major. METHODS AND RESULTS: The study included 79 patients, aged 24.2 +/- 8.0 years, with homozygous beta-thalassemia major without symptoms of heart failure with normal LV function and 51 healthy control subjects, matched for age, sex, and body surface area. Doppler echocardiographic indexes of systolic and diastolic ventricular function were assessed. Hemodynamic measurements were obtained in 8 patients by right heart catheterization. An abnormal RV relaxation pattern was evident in the patient group. The LV filling characteristics indicated increased preload without abnormal alteration, whereas catheterization findings were consistent with a high cardiac output state. Short tricuspid deceleration time (DT) had the best predictive value for subsequent cardiac events. Repeat echocardiographic study in 35 asymptomatic patients at 19 +/- 7 months demonstrated deterioration of LV systolic function, chamber enlargement, and shortening of DT of tricuspid and mitral inflow. CONCLUSIONS: In patients with homozygous beta-thalassemia major without cardiac disease, the pattern of RV filling is abnormally altered, indicating impaired relaxation. In contrast, the LV filling is compatible with increased preload, as in chronic anemia. Short DT of early tricuspid inflow carries important prognostic value. LV remodeling occurs over time along with transition toward a restrictive ventricular filling pattern.

Adolescent↗
PubMed2001

Low dose systemic heparinization combined with heparin-coated extracorporeal circulation. Effects related to platelets.

BACKGROUND: A heparin coated cardiopulmonary bypass system combined with full and low dose systemic heparinization in coronary bypass surgery was investigated in a prospective, randomised study. Roller pumps, coronary suction and an open cardiotomy reservoir were used. METHODS: One hundred and nineteen patients were divided into 3 groups: group A (n=39) had a standard uncoated extracorporeal circulation (ECC)-set and systemic heparin was given in an initial dose of 400 IE/kg body weight. During ECC activated clotting time (ACT) was kept at = or >480 sec. Group B (n=42) had the same ECC-set completely coated with low molecular weight heparin, i.v. heparin was administered in the same dose as in group A, ACT was again kept at = or >480 sec. Group C (n=38) had the same coated ECC set as group B, but i.v. heparin was reduced to 150 IE/kg and during ECC ACT was maintained of = or >240 sec. RESULTS: Platelet decrease was significantly less in both groups utilizing coated circuitry as compared to control group A. Activation of thrombocytes as marked by b-thromboglobulin (not PF4) was significantly decreased in patients treated with coated circuits combined with low dose systemic heparinization and postoperative bleeding was significantly reduced. CONCLUSIONS: We conclude that in heparin coated extracorporeal circulation combined with either full dose or reduced systemic heparinization compared to uncoated circuits platelet count reduction is significantly less. Platelet activation as marked by b-thromboglobulin and postoperative blood loss are decreased with coated equipment and low i.v. heparinization.

Adult↗
PubMed2001

[INR self-management after mechanical heart valve replacement: ESCAT (Early Self-Controlled Anticoagulation Trial)].

Severe thromboembolic and hemorrhagic complications following mechanical heart valve replacement essentially occur due to intense oral anticoagulation and fluctuating individual INR values around the target range. INR self-management can help to minimize these fluctuations. Beginning this therapeutic control immediately after mechanical heart valve replacement further reduces anticoagulant-induced complications. Included in the study were 1200 patients. The quality of oral anticoagulation also improved through INR self-management. Over an observation period of two years, nearly 80% of INR values recorded by the patients themselves were within the target therapeutic range of 2.5-4.5. This corresponds to a high significance of p < = 0.001 in favor of INR self-management. Only 64.9% of INR values monitored by family practitioners were within the desired range. The results differed slightly in quality between patient groups with different levels of training (comprehensive, secondary modern, grammar with or without university). Of patients trained in INR self-management following mechanical heart valve replacement, 91.7% maintained their competence in this technique throughout the entire follow-up period. Only 8.3% of those trained immediately after surgery were unable to continue with INR self-management.

Administration, Oral↗
PubMed2000

Electrocardiographic remodeling in patients paced for heart failure.

Congestive heart failure due to advanced coronary artery disease or dilated cardiomyopathy is often associated with intraventricular conduction delays. Electrical resynchronization is an evolving method to improve clinical and functional status. To evaluate whether pacing-induced changes in the electrocardiogram are related to hemodynamic changes, we analyzed electrocardiograms of patients enrolled in the Pacing Therapies in Congestive Heart Failure trial. The study population consisted of 42 patients, New York Heart Association functional class III-IV with a baseline QRS complex of 175 +/- 32 msec and a PR interval of 196 +/- 33 msec. The mean left ventricular ejection fraction was 0.23. Using high-resolution computer scans, we measured QRS duration of intrinsic and paced electrocardiographs at different times during the study. Results of the electrocardiographic measurements were correlated with functional results. During the crossover period, 34 episodes of biventricular pacing, 27 episodes of left ventricular pacing, and 5 episodes of right ventricular pacing occurred, each at an individual optimized atrioventricular (AV) delay. The only significant difference was that right ventricular pacing increased the QRS width by 40 msec as compared with baseline or biventricular pacing. Functional benefit, as indicated by relative increase of peak oxygen uptake (VO2) compared with baseline, was significantly correlated with shortening of paced QRS width (correlation coefficient, r = 0.55; p <0.05). After 12-month follow-up of 28 patients, we saw a slight, nonsignificant decrease of intrinsic QRS width. With regard to the underlying disease, intrinsic QRS width at baseline and at 12 months was also not significantly different between patients with coronary artery disease and dilated cardiomyopathy. This study found that right ventricular pacing causes an increase in QRS duration in patients with left bundle-branch block, whereas in left ventricular and biventricular pacing, QRS width remains unchanged. Shortening of QRS width is correlated with a pronounced relative increase of peak VO2, and thus may become a noninvasive marker of clinical efficacy. There is no evidence of remodeling of the intrinsic electrocardiogram after 12 months of pacing.

Arrhythmias, Cardiac↗
PubMed2000

[Is the estimation of the progression of valvular aortic stenosis possible?].

BACKGROUND AND OBJECTIVE: It is of great importance to assess progression of aortic valvar stenosis (AVS) when cardiac surgery is planned for other indications when established criteria for aortic valve replacement are not fulfilled at that moment. These considerations have often been ignored in prospective planning of treatment, necessitating a second cardiac surgical intervention just a few years later. The aim of this study was to establish criteria for estimating the rate of progression of AVS. PATIENTS AND METHODS: Clinical, echocardiographic and haemodynamic data were analysed for 169 patients with aortic valvar stenosis (169 men, 88 women; mean age at first cardiac catheterization [CC] 55.2 +/- 15.7 years, at second CC 63.4 +/- 15.6 years. RESULTS: The degree of AVS increases exponentially in relation to the extent of calcification (graded 0-3) and the fall in transaortic gradient (TG), from a TG > 0.6 mmHg/ml stroke volume and can be sufficiently predictable for clinical purposes. But neither age, sex nor the aetiology/pathology of the valvar defect have a sustained influence on the progression of AVS. CONCLUSIONS: These data indicate that knowing the current reduction in TG and the degree of calcification makes it possible to assess the likely progression of previously asymptomatic AVS and thus greatly facilitate the decision of whether or not to combine aortic valve replacement with another indicated cardiac operation.

Adolescent↗