Biomedical subjects

Reiner Koerfer

Publications and source records attributed to Reiner Koerfer.

At least 19 recordsLinked to original sources

PubMed2007

Self-management of oral anticoagulation therapy improves long-term survival in patients with mechanical heart valve replacement.

BACKGROUND: The Early Self-Controlled Anticoagulation Trial has demonstrated that in patients with mechanical heart valve replacement self-management of oral anticoagulation results in less major thromboembolic events than conventional measurement by the general practitioner. However, the effects of self-management on long-term survival are currently not known. METHODS: Nine hundred thirty patients participated in a follow-up study of the aforementioned trial (488 from the self-management group and 442 from the conventional group). Long-term survival was assessed 12 years after the study began using the intent-to treat analysis as well as the per protocol analysis. Univariate and multivariate analyses were performed in order to assess independent predictors of survival. RESULTS: In total, the 930 patients accrued 8,315 patient-years of observation. During follow-up, 236 patients died. According to the intent-to treat analysis, 10-year survival was 76.1% in the conventional group and 84.5% in the self-management group. The corresponding values for the per protocol analysis were 67.7% and 80.6%, respectively. Age, kind of valve surgery, and study group were independent predictors of survival. Self-management of oral anticoagulation increased long-term survival by 23% (intent-to-treat analysis) and 33% (per protocol analysis), respectively, compared with conventional measurement by the general practitioner. Possible reasons for these advantageous results in the self-management group are fewer thromboembolic events due to a higher percentage of international normalized ratio values lying in the target range compared with the conventional group. CONCLUSIONS: Data indicate that self-management of oral anticoagulation is a promising strategy in order to increase long-term survival in patients with mechanical prosthetic valves.

Administration, Oral↗

PubMed2007

Vitamin D and vascular calcification.

PURPOSE OF REVIEW: Vascular calcification is frequently found in patients with osteoporosis, atherosclerosis and chronic kidney disease, leading to high morbidity and mortality rates. The effects of vitamin D excess and deficiency on vascular calcification are reviewed in this article. RECENT FINDINGS: There is evidence from experimental studies that mediacalcinosis induced by vitamin D excess is an active and reversible process. Vitamin D excess, however, is rarely seen in the general human population. Experimental data also demonstrate that physiologic vitamin D actions include the inhibition of processes that are important for intimal and medial artery calcification such as pro-inflammatory cytokine release, adhesion molecule release, and proliferation and migration of vascular smooth muscle cells. In uremic rats, low levels of the vitamin D hormone calcitriol are associated with massive vascular and soft tissue calcifications. Whereas retrospective studies already indicate a beneficial effect of active vitamin D on mortality rates in chronic kidney disease, little is yet known about the effect of vitamin D deficiency on cardiovascular morbidity and mortality in the general population. SUMMARY: Available data indicate that vitamin D exerts a biphasic 'dose response' curve on vascular calcification with deleterious consequences not only of vitamin D excess but also of vitamin D deficiency.

Animals↗

PubMed2006

Heparin-induced thrombocytopenia in patients receiving mechanical circulatory support.

OBJECTIVES: Patients receiving mechanical circulatory support are at risk for the development of heparin-induced thrombocytopenia due to the prolonged postoperative use of heparin. We evaluated their antibody status and outcome. METHODS: Between 2003 and 2004, 115 patients received mechanical circulatory support for more than 5 days. Blood samples from postoperative day 7 were retrospectively analyzed for anti-platelet factor 4/heparin antibodies and heparin-induced platelet activation. RESULTS: Overall, 12 (10.6%) patients had heparin-induced thrombocytopenia as defined by in vitro platelet activation, 28 (24.8%) had nonactivating antibodies, and 73 (64.6%) were classified as negative for antibodies. Patients positive for heparin-induced thrombocytopenia had the highest levels of anti-platelet factor 4/heparin immunoglobulin G antibodies. Freedom from thromboembolism was 33%, 33%, and 16% at 1, 3, and 6 months for positive patients, 77%, 68%, and 55% for negative patients (P < .001), and 70%, 53%, and 53% for patients with nonactivating antibodies (P = .068), respectively. The relative risk for thromboembolism in antibody positive patients peaked in the first month of support (odds ratio 7.46, P = .002). Independent risk factors for thromboembolic events included higher anti-platelet factor 4/heparin antibody titers, female gender, and higher fibrinogen levels. CONCLUSION: Heparin-induced thrombocytopenia was more prevalent in patients receiving mechanical circulatory support than in other cardiac patients. Frequent antibody screening is recommended due to the increased risk of thromboembolism. Heparin alternatives should be subjected to clinical trials in these high-risk patients.

Antibodies↗

PubMed2006

Vitamin D insufficiency in congestive heart failure: why and what to do about it?

This article gives an overview of the current knowledge on vitamin D status in patients with congestive heart failure (CHF). A serum 25-hydroxyvitamin D level below 50 nmol/l (20 ng/ml) is generally regarded as insufficient. Available data indicate that the majority of CHF patients have 25-hydroxyvitamin D levels in the insufficiency range. Skin synthesis of vitamin D after solar ultraviolet B exposure is the most important vitamin D source for humans. However, CHF patients have relatively low outdoor activities. Consequently, a disease-related sedentary lifestyle is an important cause for the insufficient vitamin D status in CHF patients. There is also evidence from a recently performed case-controlled study that indicators of ultraviolet B exposure are already reduced in CHF patients during childhood, adolescence, and early adulthood compared to healthy controls. We present results indicating that an insufficient vitamin D status may contribute to the etiology/pathogenesis of CHF. Data include a vitamin D-mediated reduction of elevated blood pressure as well as a vitamin D-mediated prevention of enhanced parathyroid hormone levels, a pathophysiological state that contributes to cardiovascular disease. Based on population attributable risks, hypertension and cardiovascular disease have a high impact, accounting for the majority of CHF events.Theoretically, vitamin D status can be improved by adequate skin synthesis of vitamin D and/or adequate oral vitamin D intake. At present, daily oral intake of 50-100 microg vitamin D seems to be the most effective way to improve vitamin D status in CHF patients.

Heart Failure↗

PubMed2006

Triple bridge-to-transplant in a case of giant cell myocarditis complicated by human leukocyte antigen sensitization and heparin-induced thrombocytopenia type II.

Bridge-to-bridge experience has documented the feasibility of a switch from short-term to long-term mechanical circulatory support until heart transplant. We describe a case of irreversible cardiogenic shock due to giant cell myocarditis treated consecutively with extracorporal membrane oxygenation, bi-ventricular assist device, and total artificial heart. The postoperative course was complicated by human leukocyte antigen sensitization and heparin-induced thrombocytopenia type II. Our patient successfully underwent heart transplant after 10 months of support and was discharged in good condition. This case illustrates suitable device selection for myocarditis and represents two treatable immunological complications.

Adult↗

PubMed2006

Vitamin D supplementation improves cytokine profiles in patients with congestive heart failure: a double-blind, randomized, placebo-controlled trial.

BACKGROUND: Elevated circulating concentrations of proinflammatory cytokines may contribute to the pathogenesis of congestive heart failure (CHF). In vitro studies suggest that vitamin D suppresses proinflammatory cytokines and increases antiinflammatory cytokines. OBJECTIVE: We evaluated the effect of vitamin D supplementation on the survival rate and different biochemical variables in patients with CHF. DESIGN: One hundred twenty-three patients randomly received either 50 mug vitamin D(3)/d plus 500 mg Ca/d [D(+) group] or placebo plus 500 mg Ca/d [D(-) group] for 9 mo. Biochemical variables were assessed at baseline and after 9 mo. The survival rate was calculated for a follow-up period of 15 mo. RESULTS: Ninety-three patients completed the study. Significant treatment effects were observed on logarithmic-transformed serum concentrations of 25-hydroxyvitamin D (P = 0.001), parathyroid hormone (P = 0.007), tumor necrosis factor alpha (P = 0.006), and interleukin 10 (P = 0.042). 25-Hydroxyvitamin D increased by 26.8 ng/mL in the D(+) group but increased only by 3.6 ng/mL in the D(-) group. Compared with baseline, parathyroid hormone was significantly lower and the antiinflammatory cytokine interleukin 10 was significantly higher in the D(+) group after 9 mo. The proinflammatory cytokine tumor necrosis factor alpha increased in the D(-) group but remained constant in the D(+) group. The survival rate did not differ significantly between the study groups during the follow-up period. CONCLUSIONS: Vitamin D(3) reduces the inflammatory milieu in CHF patients and might serve as a new antiinflammatory agent for the future treatment of the disease. Our data provide evidence for the involvement of an impaired vitamin D-parathyroid hormone axis in the progression of CHF.

Chronic Disease↗

PubMed2005

Markers of bone metabolism in congestive heart failure.

Congestive heart failure (CHF) is a chronic disease, whose incidence is especially growing in the subpopulation of elderly people. CHF is characterized by dyspnea and fatigue at rest or with exertion, ankle swelling and pulmonary edema. Cardiac transplantation is the ultimate therapeutic measure in patients with end-stage CHF. Some risk factors associated with CHF such as low mobility, renal failure, and prescription of specific drugs may predispose patients to develop osteoporosis. This review article gives an overview about markers of bone metabolism in CHF patients as well as in heart transplant recipients. At first, the physiology of bone metabolism is summarized. Then, a short description of different bone formation and resorption markers is presented. They can be used to characterize actual bone metabolism and can be helpful to explain possible mechanisms of bone loss. Regarding pre-transplant CHF patients, available data indicate that the disturbances in bone metabolism are only subtle. Heart transplant recipients, however, are at increased risk for osteoporotic bone loss due to the use of immunosuppressive agents such as corticosteroids and calcineurin inhibitors. Preventive strategies are able to normalize bone metabolism and to attenuate the high bone loss during the first year after heart transplantation.

Biomarkers↗

PubMed2005

Immunosuppressive therapy with everolimus can be associated with potentially life-threatening lingual angioedema.

Everolimus has recently received approval for immunosuppressive therapy in heart transplant recipients in Austria and Germany. At our heart center we have treated 114 patients with everolimus since January 2004. Here we describe 6 cases of lingual angioedema (corresponding to 5.3% of the patients). Symptoms occurred within 2 to 41 days after initiation of therapy. In 5 out of the 6 patients, lingual angioedema disappeared with anti-allergic treatment alone. However, in one patient, two severe recurrent episodes of lingual angioedema occurred so that therapy had to be discontinued. We conclude that the potentially life-threatening condition of lingual angioedema should be considered a severe drug reaction after initiation of everolimus therapy in heart transplant recipients.

Angioedema↗

PubMed2005

The Bad Oeynhausen concept of INR self-management.

BACKGROUND: A significant number of patients depend on the intake of vitamin K antagonists for prevention and treatment of thromboembolic events. The development of portable anticoagulation monitors has enabled self-testing and self-adjustment of anticoagulation therapy. OBJECTIVE: To describe the principles of a training course to learn INR self-management and to illustrate reliability of our concept. DESCRIPTION: The training is divided into an early postoperative training, an ambulatory training six months later, and a 24 hours care and consultation. According to our concept, each patient who depends on long-term anticoagulation therapy is able to learn INR self-management. Reliability of our concept has been proved in two prospective, randomized clinical trials. STUDY RESULTS: A study with 1,155 patients has demonstrated that INR values lie more often in the predetermined target range in the INR self-management group if compared to the conventional group (79.2% vs. 64.9%; P < 0.001). Moreover, this study has demonstrated that self-management can lead to a reduction of thromboembolism (1.5% vs. 2.8%; P < 0.05), and to a lower lethality if compared to conventional INR management (3.5% vs 6.0%; P < 0.025). A second study with 1,816 patients has confirmed that INR self-management results in a high percentage of INR values in the target range (76%), even though target INR-range is reduced and narrowed. Thus, low dose INR self-management did not increase the risk of thromboembolism while avoiding the zone of higher risk for bleeding, beginning from INR > 3.5. CONCLUSIONS: The Bad Oeynhausen concept of INR self-management is a promising tool to achieve low hemorrhagic complications without increasing the risk of thromboembolic complications. It can thus be successfully applied to patients with an indication for permanent anticoagulation therapy.

Anticoagulants↗

PubMed2005

Left ventricular pacing through the anterior interventricular vein in a patient with mechanical tricuspid, aortic and mitral valves.

Transvenous endocardial pacemaker implantation is contraindicated in patients after mechanical tricuspid valve replacement. A 76-year-old woman who suffered from bradyarrhythmia was implanted with a left ventricular pacing lead through a transvenous coronary vein after aortic, mitral, and tricuspid valve replacements. There were no complications and the stimulation thresholds were stable. The use of coronary vein leads provides a minimally invasive approach, safety, and effective stimulation for patients with a mechanical tricuspid valve.

Aged↗

PubMed2005

Three cases of orthotopic heart transplantation for arrhythmogenic right ventricular cardiomyopathy.

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a cardiomyopathy that primarily affects the heart muscle in the right ventricle. The ventricular muscle is replaced by fatty or fibrous tissue in a diffuse or spotty process. We performed orthotopic heart transplantations in 3 patients and all patients are alive. When ARVC has progressed to heart failure in the right or left ventricles, orthotopic heart transplantation is an effective therapeutic option.

Adult↗

PubMed2005

Clinical outcome of patients with deep sternal wound infection managed by vacuum-assisted closure compared to conventional therapy with open packing: a retrospective analysis.

BACKGROUND: It is suggested that the vacuum technique is a promising new method for the therapy of mediastinitis, but reliable investigations are currently almost completely lacking. We therefore compared clinical outcome of patients whose sternal infection was managed with the vacuum-assisted closure system or with the conventional procedure of open packing. METHODS: We performed a retrospective analysis in 68 cases of sternal wound infection that were identified at our Heart Center between September 1998 and September 2003. Thirty-five patients could be allocated to the vacuum group and 33 patients to the conventional group. We compared the time interval from sternal infection until freedom of microbiological cultures, in-hospital stay, the status at discharge (rewired or open sternum), the time interval until wound healing was achieved, and survival rates. Moreover, we compared serum levels of C-reactive protein and blood leukocyte counts on admission, at diagnosis of sternal infection, and at different points of time until discharge. RESULTS: Baseline characteristics and blood factors did not differ between the two study groups at diagnosis of sternal infection. Moreover, the number of prescribed antibiotics was similar, and the C-reactive protein level and blood leukocyte counts at discharge were comparable in both groups. However, freedom from mediastinal microbiological cultures was achieved earlier (p < 0.01), C-reactive protein levels declined more rapidly (p < 0.025), in-hospital stay was shorter (p < 0.01), rewiring was earlier (p < 0.01), and survival tended to be higher (p < 0.15) in the vacuum group compared to the conventional group. CONCLUSIONS: This retrospective analysis could demonstrate that the vacuum technique improves the medical outcome of patients with mediastinitis compared with the conventional technique of open packing.

Adult↗

PubMed2005

Low-dose international normalized ratio self-management: a promising tool to achieve low complication rates after mechanical heart valve replacement.

BACKGROUND: International normalized ratio (INR) self-management can significantly reduce INR fluctuations, bleeding, and thromboembolic events compared with INR control managed by general practitioners. However, even patients with INR self-management may have an increased risk of bleeding if their INR value is above 3.5. This study evaluated the compliance, clinical complications, and survival of patients after mechanical heart valve replacement with low-dose INR self-management compared with conventional-dose anticoagulation. METHODS: Group 1 (n = 908) received low-dose anticoagulation with a target INR range of 1.8 to 2.8 for aortic valve replacement and 2.5 to 3.5 for mitral or double valve replacement. Group 2 (n = 910) received conventional-dose anticoagulation with a target INR range of 2.5 to 4.5 for all heart valve prostheses. RESULTS: In groups 1 and 2, 76% and 75% of INR values, respectively, were in the target range. Results did not differ according to schooling and age. The rate of thromboembolic events per patient year was 0.18% in group 1 and 0.40% in group 2 (p = 0.210). The rate of bleeding complications was 0.74% for group 1 and 1.20% for group 2 (p = 0.502). In most patients with clinically relevant bleeding, these complications occurred although their measured INR values were below 3.5. The survival rate did not differ between the study groups (p = 0.495). CONCLUSIONS: Low-dose INR self-management is a promising tool to achieve low hemorrhagic complications without increasing the risk of thromboembolic complications. INR self-management is applicable for all patients in whom permanent anticoagulation therapy is indicated. Even INR values below 3.5 can bear the risk of bleeding complications.

Adolescent↗

PubMed2005

CardioWest total artificial heart: Bad Oeynhausen experience.

BACKGROUND: The use of ventricular assist devices (VAD) has become a widely accepted therapeutic option. However, there are still limitations to the patient collective eligible for VAD placement, who might therefore benefit from the implantation of a total artificial heart. We present the first German single-center experience with the CardioWest total artificial heart (TAH) (SynCardia Systems, Tucson, AZ) in 42 patients. METHODS: Between February 2001 and December 2003, 42 patients (37 men, 5 women, mean age 51 +/- 13 years) received a TAH at our Center. Their body surface area ranged between 1.5 and 2.4 (mean, 1.9 +/- 0.19) m2. All patients were in persistent cardiogenic shock in spite of maximum inotropic support and had numerous preoperative risk factors (intraaortic balloon pumping, mechanical ventilation, acute renal failure, previous cardiac surgery, recent cardiopulmonary resuscitation). RESULTS: Duration of support was 1 to 291 days. Eleven patients (26%) underwent successful transplantation; 9 of them could be discharged home. Twenty-two patients died under support, 21 of them from multiple organ failure and 1 patient from a technical problem. Nine patients are still on the device, 4 of them at home after the original CardioWest console was replaced by the Berlin Heart EXCOR driver (Berlin Heart, Berlin, Germany). Exceptional results were achieved in patients with cardiogenic shock after cardiac surgery or after acute myocardial infarction. CONCLUSIONS: Against the background of the extremely poor preoperative situation of our patients, the overall survival rate of 48% can be considered as favorable. A prospective, randomized study is planned to find out whether patients with idiopathic dilated or ischemic cardiomyopathy are more likely to benefit from a biventricular assist device or a total artificial heart.

Adult↗

PubMed2005

A multidisciplinary network to save the lives of severe, persistent cardiogenic shock patients.

BACKGROUND: Severe, persistent cardiogenic shock is associated with very high morbidity and lethality. We therefore tried to improve the outcome of these patients using a network between local hospitals and a specialized heart center that has facilities for transplantation and ventricular assist device (VAD) implantation. METHODS: Between 1998 and 2000, 50 patients, who were in cardiogenic shock (mean age 49 years, SD 14) despite high doses of at least three inotropic agents, were admitted to our specialized heart center. During the first 12 hours, we tried to stabilize the patient's condition, to reduce inotropic support agents, and to keep cardiac index above 2.4 L.min(-1).m(-2). According to this strategy, patients were allocated to medical treatment only, emergency VAD therapy, urgent VAD implantation, or heart transplantation. To assess variables potentially influencing patients' outcome, we performed univariate and multivariate analyses. RESULTS: Early in-hospital mortality was 36% and late mortality was 10%. Overall survival at 1, 6, and 12 months of follow-up was 70%, 56%, and 52%, respectively. Even when the heart transplant patients were excluded, overall 12-months survival after cardiogenic shock was still 50%. Higher age, and the absence of sinus rhythm were the only independent risk factors for 12-month mortality. CONCLUSIONS: Our data show that a network between cardiology departments of local hospitals and specialized heart centers can be life-saving for severe, persistent cardiogenic shock patients.

Adult↗

PubMed2005

Putting cardiovascular disease and vitamin D insufficiency into perspective.

The aetiology of CVD is still not completely understood. The present review article summarises data supporting the hypothesis that an insufficient vitamin D status may contribute to the worldwide high prevalence of CVD. Human vitamin D status primarily depends on skin exposure to the UVB spectrum of the sunlight. Epidemiological data indicate that geographic latitude, altitude, season, and the place of residence (urban or rural) are associated with CVD mortality. Interestingly, all these factors also have an influence on human UVB exposure and thus on vitamin D status. Several mechanisms might be responsible for a protective role of vitamin D in CVD. These mechanisms include the inhibition of vascular smooth muscle proliferation, the suppression of vascular calcification, the down regulation of pro-inflammatory cytokines, the up regulation of anti-inflammatory cytokines, and the action of vitamin D as a negative endocrine regulator of the renin-angiotensin system. The first intervention trials indicate that vitamin D may suppress cardiovascular risk markers. However, more controlled clinical trials are needed to investigate whether optimal oral vitamin D supplementation is able to reduce CVD morbidity and mortality.

Calcinosis↗

PubMed2005

Pharmacokinetics and bioavailability of mycophenolic acid after intravenous administration and oral administration of mycophenolate mofetil to heart transplant recipients.

The aim of this prospective study was to characterize the multiple-dose pharmacokinetics of mycophenolic acid (MPA) after administration of a 3-hour intravenous (IV) infusion of mycophenolate mofetil (MMF, CellCept) at a dose level of 1.5 g every 12 hours for 5 full days to cardiac allograft recipients and to compare the bioavailability of MPA after a switch from the IV infusion to an oral dose of 1.5 g every 12 hours from day 6. In addition to MMF, patients received cyclosporine and prednisolone. Blood (EDTA) samples for full pharmacokinetic profiles were obtained for 9 patients on days 3 and 5 (IV MMF) and on days 6 and 10 (oral MMF). They were centrifuged within 45 minutes of collection, and plasma was stabilized by addition of ortho-phosphoric acid to prevent in vitro conversion of MMF to MPA. Plasma concentrations of MPA were determined using a validated HPLC procedure. The median MPA AUC on day 6 (29.7 mg.h/L) after the first oral dose was slightly lower than the AUCs on the other study days (34.2, 33.8, and 33.8 mg.h/L on days 3, 5, and 10, respectively). Pairwise comparison of the individual days revealed statistically significant (P<0.05) differences between day 6 and day 3 and between day 5 and day 3. The Cmax on day 6 was significantly lower than that on study days 3 and 5. The bioavailability of MPA from the oral MMF formulation was estimated as the ratio of the AUC on day 6 or 10 to the AUC on day 5 when steady state was presumed to have been reached with the IV formulation. The mean ratios (expressed as percentage) for the log-transformed AUCs were 91.6% and 107.8% on days 6 and 10, respectively, relative to day 5. The 90% confidence interval (CI) on day 6 (79.3% to 105.8%) was marginally below the range (80%-125%) required to conclude that the formulations are bioequivalent, whereas on day 10 the 90% CI (93.3% to 124.7%) was within this range. In the case of the Cmax values, however, the 90% confidence intervals fell outside of this range (day 6, 57.2% to 92.8%; day 10, 70.6% to 114.9%). The results of this study show that heart transplant recipients receiving the IV formulation of MMF (1.5 g BID) are not subject to a greater drug exposure than that seen with the oral formulation (1.5 g BID) and that the oral MMF formulation shows excellent, high, and consistent bioavailability (mean 95%) based on comparison with the IV formulation.

Administration, Oral↗

PubMed2005

Endocardial pacing after Fontan-type procedures.

BACKGROUND: Sinus node dysfunction is a frequent complication of Fontan-type procedure. Epicardial pacing is considered as the standard treatment for these patients. METHODS AND RESULTS: We evaluated an endocardial approach in seven patients using a 4.1 French bipolar lumenless lead (SelectSecure) that is positioned through a steerable guiding catheter. Either a purely transvenous or an open transatrial approach can be used for lead placement. The smallest child weighed 12 kg. Individual anatomy was assessed preimplantation using magnetic resonance imaging and injection of radiographic contrast agent through the guiding catheter. A pullback pressure recording was used to confirm unimpaired blood flow into the pulmonary artery. Five of our seven patients underwent de novo transvenous atrial lead implantation for AAIR pacing. In the remaining two patients, both atrial and ventricular leads were inserted. One patient with an intraatrial tunnel underwent transvenous-lead placement. The remaining patient with an extracardiac conduit received atrial and ventricular leads implanted through a guiding catheter inserted through an atriotomy. The postoperative management included short- or long-term oral anticoagulation. CONCLUSIONS: Transvenous endocardial lead implantation avoids the problem of increasing capture thresholds typically observed with epicardial leads. Due to its high tensile strength and lumenless design, the isodiametric lead is expected to remain extractable for an extended period of time.

Adolescent↗