Biomedical subjects

M Weyand

Publications and source records attributed to M Weyand.

At least 37 records · Page 2Linked to original sources

PubMed2001

Modulating IL-6 and IL-10 levels by pharmacologic strategies and the impact of different extracorporeal circulation parameters during cardiac surgery.

Postoperative morbidity after coronary artery bypass grafting (CABG) using cardiopulmonary bypass (CPB) can be influenced by pro- and anti-inflammatory cytokines like interleukin 6 (IL-6) and IL-10 triggering and balancing the acute phase response. The extent of cytokine release can be modulated by different methods. This prospective randomized study examines the effect of treatment of patients with steroid (group 1, 250 mg of prednisolone)(Solu-Decortin H)), aprotinin (group 2, 6 Mio. KIU [kallikrein inhibitory units] aprotinin [Trasylol]), and heparine coating of the artificial surface (group 3, Bioline) on the systemic release of IL-6 and IL-10 in four groups of 40 patients with coronary artery disease (CAD) scheduled for CABG. Group 4 (standard medication) served as control. Twenty hemodynamic and biochemical parameters of the CPB were analyzed regarding correlation to cytokine levels measured by enzyme-linked immunosorbent assay (ELISA). In group 1, IL-6 was suppressed compared to the control (P< 0.01). IL-10 was upregulated (P< 0.01). In group 2, cytokine release was similar to group 1. Using heparin-coated circuits in group 3 led to IL-10 upregulation (P < 0.05) and IL-6 suppression (P < 0.05). We found an exponential relationship between IL-10 levels (IL-6 levels) and cardiac ischemia time, duration of CPB, and the extent of negative base excess. An inverse relationship was found for IL-10 (IL-6) levels and venous O2 saturation (SvO2), and mean arterial pressure (MAP). Hypothermia (<34 degrees C) reduced IL-10 and IL-6 release, whereas long duration of hypothermia correlated with higher IL-10 and IL-6 release. Cytokine release after extracorporeal circulation (ECC) can be modulated pharmacologically and by distinct perfusion regimen.

Aged↗

PubMed2000

Structural basis for the impaired channeling and allosteric inter-subunit communication in the beta A169L/beta C170W mutant of tryptophan synthase.

We determined the 2.25 A resolution crystal structure of the betaA169L/betaC170W mutant form of the tryptophan synthase alpha(2)beta(2) complex from Salmonella typhimurium complexed with the alpha-active site substrate analogue 5-fluoro-indole-propanol-phosphate to identify the structural basis for the changed kinetic properties of the mutant (Anderson, K. S., Kim, A. Y., Quillen, J. M., Sayers, E., Yang, X. J., and Miles, E. W. (1995) J. Biol. Chem. 270, 29936-29944). Comparison with the wild-type enzyme showed that the betaTrp(170) side chain occludes the tunnel connecting the alpha- and beta-active sites, explaining the accumulation of the intermediate indole during a single enzyme turnover. To prevent a steric clash between betaLeu(169) and betaGly(135), located in the beta-sheet of the COMM (communication) domain (betaGly(102)-betaGly(189)), the latter reorganizes. The changed COMM domain conformation results in a loss of the hydrogen bonding networks between the alpha- and beta-active sites, explaining the poor activation of the alpha-reaction upon formation of the aminoacrylate complex at the beta-active site. The 100-fold reduced affinity for serine seems to result from a movement of betaAsp(305) away from the beta-active site so that it cannot interact with the hydroxyl group of a pyridoxal phosphate-bound serine. The proposed structural dissection of the effects of each single mutation in the betaA169L/betaC170W mutant would explain the very different kinetics of this mutant and betaC170F.

Base Sequence↗

PubMed2000

[Late postoperative cardiac arrhythmias after total cavopulmonary anastomosis and correlation with age of the patients at operation].

Late postoperative arrhythmias are a common problem associated with significant morbidity following Fontan operations. We analyzed in our patients whether age at the time of a modified Fontan procedure (total cavopulmonary connection) has an influence on the frequency of late postoperative arrhythmias. We examined all 66 long-term surviving patients who underwent a total cavopulmonary connection (TCPC) in our center during a nine year period. At the time of TCPC, 31 children were younger (group I) and 35 children were older than 4 years (group II). The follow-up period was almost identical in both groups (group I: 4.29 years, group II: 4.52 years). We evaluated all ecgs performed at maximum intervals of 6 months and all Holter ecgs performed at intervals of 12 months. Atrial tachyarrhythmias (supraventricular tachycardias, atrial flutter) were registered in six patients (9%). All of these patients belonged to group II (17%). Ventricular arrhythmias (couplets, ventricular tachycardia) were found in 3% of the younger and 17% of the older patients. Abnormalities of sinus node function were registered in equal frequency in younger and older children (group I: 35%, group II: 31%), while pauses with a duration of > 2 s where present only in older children (group II: 14%). Pacemaker implantation or antiarrhythmic therapy became necessary in 10/66 patients (15%) affecting none of the children who underwent the TCPC < 4 years (group I) but 10/35 children (group II) who underwent the TCPC at an older age (29%). According to our findings in the medium-term follow-up after TCPC, atrial tachyarrhythmias and complex ventricular arrhythmias are registered less frequently in children who underwent the modified Fontan procedure at an age of less than 4 years. Although further studies will have to show whether these differences persist in the long-term follow-up, these findings represent an additional argument for the elective performance of modified Fontan operations at an age of less than 4 years.

Adolescent↗

PubMed2000

Operative techniques and strategies for minimally invasive fetoscopic fetal cardiac interventions in sheep.

BACKGROUND: Recent efforts to develop procedures for fetoscopic fetal cardiac interventions have been prompted by the development of severe secondary damage to the fetal heart due to semilunar valvar obstructions and the poor outcome of therapy-refractory fetal arrhythmias. The purpose of our manuscript is to analyze and share our experience with the creation of an operative setup for these procedures in sheep. METHODS: We studied a total of 48 fetal sheep between 81 and 106 days of gestation (term, 145 days). After entering the amniotic cavity by a percutaneous approach, we performed various fetoscopic fetal cardiac procedures. We analyzed the success of percutaneous fetal access, methods of trocar support, the incidence and management of trocar dislodgement or accidental insertion into the chorioamniotic space, problems related to amniotic insufflation and trocar placement, as well as techniques for fetal posturing and uterine closure. RESULTS: Percutaneous fetal access was achieved in all sheep. The use of resterilizable trocars substantially decreased the costs of our procedures. Utilizing a percutaneous transuterine purse-string suture for trocar support helped to minimize the number of nonabsorbable T-fasteners remaining inside the uterus postoperatively. As complications such as trocar dislodgement, insertion of the trocar into the chorioamniotic space, and problems with intraamniotic insufflation and gas loss were mastered, conversion to an open operative approach was never required. A novel strategy that we devised for percutaneous fetal posturing permitted adequate fetal posturing with ease and minimal trauma to the fetal skin. CONCLUSION: As operative techniques have become more refined, the feasibility of performing fetoscopic fetal cardiac interventions in human fetuses now depends mainly on technical improvements in imaging and interventional catheters, as well as advances in pacemaker equipment.

Animals↗

PubMed2000

Selection and management of ventricular assist device patients: the Muenster experience.

BACKGROUND: Because of the growing discrepancy between the availability of donor organs and the number of patients with end-stage heart disease who need heart transplantation, a larger proportion of patients waiting for a suitable donor heart require pre-operative mechanical circulatory assistance. The criteria for the selection and management of these patients as applied at Muenster University Hospital are reviewed. METHODS: The study population consists of 631 patients referred to our center for transplantation between January 1, 1990, and December 31, 1996. Two hundred ninety-seven patients were listed for transplantation and 157 were transplanted. Of 41 patients who underwent implantation of a ventricular assist device (n = 34, Novacor; n = 6, TCI HeartMate; n = 1, Medos), 39 received the device as a bridge to transplantation and 2 as permanent support. For the purpose of the analysis, the study population was divided into 3 groups (elective bridging, urgent bridging, emergency bridging) and compared with heart transplant candidates who did not require mechanical circulatory assistance. RESULTS: Patients who underwent elective or urgent assist-device implantation were younger and had greater hemodynamic compromise than the remainder of patients waiting for heart transplantation, as suggested by a higher functional class and lower mean arterial pressure, cardiac index, serum sodium, and pulmonary artery wedge pressure. Survival of patients who electively underwent implantation of an assist device was better than that of patients who were stable on the waiting list and did not undergo heart transplantation during follow-up. CONCLUSIONS: This finding suggests that earlier implantation of assist devices may facilitate resolution of organ dysfunction before heart transplantation.

Adult↗

PubMed1999

Crystal structure of wild-type tryptophan synthase complexed with the natural substrate indole-3-glycerol phosphate.

We used freeze trapping to stabilize the Michaelis complex of wild-type tryptophan synthase and the alpha-subunit substrate indole-3-glycerol phosphate (IGP) and determined its structure to 1. 8 A resolution. In addition, we determined the 1.4 A resolution structure of the complex with indole-3-propanole phosphate (IPP), a noncleavable IGP analogue. The interaction of the 3'-hydroxyl of IGP with the catalytic alphaGlu49 leads to a twisting of the propane chain and to a repositioning of the indole ring compared to IPP. Concomitantly, the catalytic alphaAsp60 rotates resulting in a translocation of the COMM domain [betaGly102-betaGly189, for definition see Schneider et al. (1998) Biochemistry 37, 5394-5406] in a direction opposite to the one in the IPP complex. This results in loss of the allosteric sodium ion bound at the beta-subunit and an opening of the beta-active site, thereby making the cofactor pyridoxal 5'-phosphate (PLP) accessible to solvent and thus serine binding. These findings form the structural basis for the information transfer from the alpha- to the beta-subunit and may explain the affinity increase of the beta-active site for serine upon IGP binding.

Binding Sites↗

PubMed1999

Ambulatory care of patients with left ventricular assist devices.

BACKGROUND: Left ventricular assist devices (LVAD) have revolutionized the treatment of patients with acute and chronic heart failure as they provide a high quality of life. We report on our experience with patients receiving ambulatory care after LVAD implantation. METHODS AND RESULTS: Since July 1995, 46 patients with a mean age of 45+/-11 years underwent implantation of an electrically driven LVAD with portable controller and batteries. Sixteen (35%) patients bridged >30 days were treated in part on an outpatient basis. After LVAD implantation, they were treated in the hospital for 86+/-32 days (range 40 to 153 days). Afterward, they received ambulatory care for 74+/-76 days (range 2 to 301 days, total experience 1206 days). In 13 cases, the outpatient treatment was interrupted by 1.7+/-1.7 readmissions, for a total of 32+/-42 days (median 19 days). Reasons for readmission included systemic or drive line infections (incidence 0.0066 per outpatient day), suspected or true thromboembolic events (incidence 0.0066 per outpatient day), and suspected malfunction of the LVAD. One patient supported as alternative to transplantation died after cerebral bleeding after 244 days, 1 patient with a history of acute myocarditis had ventricular fibrillation during LVAD assist while being at home for 177 days and died in a low output state, 10 patients were given transplantation after a mean support interval of 206+/-88 days, and 4 patients currently await heart transplantation. CONCLUSIONS: Outpatient treatment after LVAD implantation is feasible, and severe complications are uncommon.

Adult↗

PubMed1999

X-ray structure determination of a vanadium-dependent haloperoxidase from Ascophyllum nodosum at 2.0 A resolution.

The homo-dimeric structure of a vanadium-dependent haloperoxidase (V-BPO) from the brown alga Ascophyllum nodosum (EC 1.1.11.X) has been solved by single isomorphous replacement anomalous scattering (SIRAS) X-ray crystallography at 2.0 A resolution (PDB accession code 1QI9), using two heavy-atom datasets of a tungstate derivative measured at two different wavelengths. The protein sequence (SwissProt entry code P81701) of V-BPO was established by combining results from protein and DNA sequencing, and electron density interpretation. The enzyme has nearly an all-helical structure, with two four-helix bundles and only three small beta-sheets. The holoenzyme contains trigonal-bipyramidal coordinated vanadium atoms at its two active centres. Structural similarity to the only other structurally characterized vanadium-dependent chloroperoxidase (V-CPO) from Curvularia inaequalis exists in the vicinity of the active site and to a lesser extent in the central four-helix bundle. Despite the low sequence and structural similarity between V-BPO and V-CPO, the vanadium binding centres are highly conserved on the N-terminal side of an alpha-helix and include the proposed catalytic histidine residue (His418(V-BPO)/His404(V-CPO)). The V-BPO structure contains, in addition, a second histidine near the active site (His411(V-BPO)), which can alter the redox potential of the catalytically active VO2-O2 species by protonation/deprotonation reactions. Specific binding sites for the organic substrates, like indoles and monochlordimedone, or for halide ions are not visible in the V-BPO structure. A reaction mechanism for the enzymatic oxidation of halides is discussed, based on the present structural, spectroscopic and biochemical knowledge of vanadium-dependent haloperoxidases, explaining the observed enzymatic differences between both enzymes.

Amino Acid Sequence↗

PubMed1999

Coronary artery bypass grafting with an expanded polytetrafluoroethylene graft.

BACKGROUND: We report our experience with the Perma-Flow aortocoronary-right heart graft in 15 patients in whom autologous conduits were not available. METHODS: Fifteen patients received 39 coronary anastomoses--10 to left anterior descending coronary artery branches, 15 to circumflex coronary artery branches, and 14 to branches of the right coronary artery. Early angiography was done in 11 patients. RESULTS: One patient died on postoperative day 17 of multiorgan failure. The graft was patent at postmortem examination. Of 30 coronary anastomoses at risk, 24 were patent. Three connections to the left anterior descending system were occluded in patients with an additional internal mammary artery graft to the same coronary system, and three connections to the circumflex system were occluded in patients with a history of major posterior infarction. Three of five distal anastomoses to the right atrial appendage were occluded, whereas all six connections to the superior vena cava were patent. None of the patients had shown recurrent angina at a mean follow-up of 10.9 months (range, 2-39 months). CONCLUSIONS: The synthetic Perma-Flow coronary graft appears to be a safe alternative in patients in whom arterial or venous conduits are not available. Competitive flow may lead to anastomotic occlusions. The appropriate site for the distal arteriovenous fistula seems to be the superior vena cava.

Blood Vessel Prosthesis↗

PubMed1999

A simple new model of physiologically working heterotopic rat heart transplantation provides hemodynamic performance equivalent to that of an orthotopic heart.

BACKGROUND: The widely used non-volume-loaded abdominal heterotopic heart transplant (NL) in rats undergoes atrophy after transplantation. Various techniques have been designed to load the transplanted heart because of its potential immunological impact. Our aim was to create a volume-loaded heterotopic heart transplantation model (VL) capable of ejection and practical for routine studies. Using this model, we tested the hypothesis that VL isografts would retain myocardial performance comparable to native hearts (NH). METHODS: Heterotopic hearts were transplanted using and end-to-side anastomosis between the donor's superior vena cava and the recipient's abdominal inferior vena cava. The right ventricle loads the left ventricle (LV) via a direct anastomosis of the pulmonary artery to the left atrium. The LV ejects volume through an end-to-side anastomosis of the donor's aorta to the recipient's abdominal aorta. Hemodynamic data (systolic and diastolic LV pressures, dP/dt max and min, tau) were studied in-situ (at baseline and after adding volume) and in a Langendorff perfusion system (at baseline and after stimulation with isoproterenol) 2 weeks after transplantation. RESULTS: In situ systolic pressure and diastolic function of VL was superior to NL, and beta-adrenergic stimulated performance in the Langendorff perfusion of VL showed hemodynamic performance equivalent to NH, unlike NL which had a diminished response. CONCLUSION: This technique results in a volume-loaded ejecting heart transplant model that preserves anatomical structures. The VL can be evaluated in situ and after explantation in Langendorff perfusion system and may offer advantages if workload of the graft is of significance to the study performed.

Abdomen↗

PubMed1999

Effective gene transfer in the rat myocardium via adenovirus vectors using a coronary recirculation model.

BACKGROUND: Gene therapy promises to play an important role in the treatment of heart disease and in transplantation. The limited effectiveness of gene transfer, however, remains an unresolved problem. The aim of the study was to create a model for more effective gene transfer using adenovirus vectors carrying the lacZ-reporter gene (AdV-lacZ). METHODS: Beating Lewis rat hearts perfused with oxygenated Krebs-Henseleit solution were harvested, after which an atrial septal defect (ASD) was created. All vessels were tied and AdV-lacZ was injected into the aortic root. The solution was recirculated through the ASD to the left side of the heart and pumped back to the coronary arteries by the left ventricle. Incubation was allowed for 20 min at 15 degrees C and the hearts were subsequently transplanted heterotopically in syngeneic rats. This method was compared to AdV-lacZ injection into cardioplegic hearts. The hearts were harvested after 2, 7, or 14 days and evaluated histologically for expression of the lacZ gene. RESULTS: Maximal gene expression was achieved after 7 days by the recirculation model. There was less efficient gene expression at day 2 and at day 14. No evidence of ischemic injury of the myocardium was noticed histologically. Almost no successful gene expression was seen in the arrested hearts. CONCLUSION: This novel recirculation method lets the vector be repeatedly exposed to the endothelium, resulting in an effective gene expression after 7 days incubation time rather than after 14, when a decline has set in presumably due to immunologic response.

Adenoviridae↗

PubMed1999

Left ventricular assist system support is associated with persistent inflammation and temporary immunosuppression.

BACKGROUND: In patients undergoing left-ventricular assist system support, it has not been elucidated to which extent mechanical circulatory support itself as opposed to the underlying condition of endstage heart-failure contributes to perturbation of immune homeostasis. METHODS: In eleven heart transplant candidates who had to undergo Novacor left-ventricular assist device bridging, we prospectively sampled interleukin-6, T-cell and monocyte subsets and compared them to fifteen UNOS status II patients awaiting cardiac transplantation on medical heart failure treatment as outpatients at the time of LVAS implantation/listing decision as well as 2.0+/-1.2 months and 4.5+/-2.3 months later. In order to assess deviations in both groups from normal values, thirty-two healthy subjects served as reference group. RESULTS: Patients undergoing Novacor bridging had higher C-reactive protein, leukocyte, neutrophil, and monocyte levels at all three times, and exhibited lower CD3 +, CD4+, CD3+/CD45 RO T-cell and natural killer cell counts than medically treated patients awaiting transplantation 2 months after the LVAS implantation/listing decision. In comparison to controls, both groups had higher levels of inflammatory activation and lower levels of immunocompetence at all three times. CONCLUSIONS: While both groups of endstage heart failure patients show immunological alterations compared to controls, patients who have to be bridged by the Novacor LVAS exhibit a more pronounced activation of inflammatory markers. This may be due to more advanced heart failure but the device itself also may contribute to more pronounced inflammation and a temporary suppression of immunocompetent cells.

Adult↗

PubMed1999

Use of an intraaortic balloon pump in patients with impaired left ventricular function.

Prophylactic use of an intraaortic balloon pump (IABP) prior to open-heart surgery in patients with impaired left ventricular function is still under debate. Patients with left ventricular ejection fraction (LVEF) < 40% were therefore compared according to time of IABP placement, viz. preoperative (n = 56), intraoperative (n = 40) or postoperative (n = 17), and also with patients who did not receive mechanical support despite LVEF < 40% (n = 78). The main indication for preoperative IABP insertion was severely impaired left ventricular function (80%), while patients with intraoperative or postoperative IABP placement mainly presented with low cardiac-output syndrome (70%/53%). Preoperative IABP was associated with a low mortality rate (8.9%), whereas patients with intraoperative or postoperative IABP placement had a high mortality risk and an increased catecholamine requirement. Of the patients scheduled for surgery without prophylactic IABP, 19% required intra- or postoperative insertion. Prophylactic placement of IABP thus reduced the mortality rate as well as the postoperative need for mechanical and catecholamine support. Need for intraoperative IABP insertion was associated with high mortality, whereas the outcome after postoperative IABP placement depended on the indication for the measure.

Aged↗

PubMed1998

Cerebral and systemic embolization during left ventricular support with the Novacor N100 device.

BACKGROUND: Patients undergoing implantation of left ventricular assist systems (LVAS) are prone to thromboembolic complications. We analyzed the incidence, clinical findings, and outcome of neurologic and systemic thromboembolic events (TE) in patients with the Novacor N100 LVAS. In a subset of patients, transcranial Doppler sonography was used to detect microembolic signals. METHODS: Thirty-six patients underwent implantation of a Novacor N100 LVAS for various reasons. The surgical procedure was elective in 18 patients and scheduled on an urgent or emergency basis in another 18 patients. The assist period lasted from 17 to 336 days (109 +/- 88 days); 22 patients were forwarded to heart transplantation after being supported for 140 +/- 87 days. RESULTS: Clinical cerebral embolism was evident in 17 patients (47%). Thromboembolic events were singular in 8 and multiple in 9 patients; in the latter up to 10 TE occurred (mean +/- SD, 1.4 +/- 2 TE). Leading neurologic symptoms were unilateral hemiplegia in 11, as well as ocular symptoms and aphasia in 12 patients each. Noncerebral TE were detected in 4 patients, 2 of whom underwent an emergency operation for intestinal and iliac artery occlusion. The incidence of TE did not correlate strongly with the interval of LVAS support. Cerebral computed tomography confirmed lesions in 58% of patients. Transcranial Doppler sonography detected microembolic signals on 67% of all recordings, with the microembolic signals being more frequent on days with clinically manifest TE. The outcomes were good, as only 2 patients suffer from neurologic sequelae. CONCLUSIONS: Thromboembolism is still a major threat for patients with LVAS implantation. Neurologic sequelae are frequent but have a favorable prognosis, and systemic complications occur considerably less often. Patient selection, adequate anticoagulation, and transcranial Doppler sonography may help to reduce the incidence of TE.

Adult↗

PubMed1998

Neonatal mechanical bridging to total orthotopic heart transplantation.

BACKGROUND: Until recently, newborns with medically intractable cardiac failure caused by congenital malformations were mostly doomed to death because of the severity of the disease, which precludes a palliative operation, or because of fatal deterioration before availability of a suitable donor heart. METHODS: The recently developed paracorporeal pneumatically driven Medos HIA ventricular assist device offers a therapeutic option for these small infants because it is manufactured in various sizes and is even suitable for cardiac assistance in neonates with a body surface area less than 0.3 m2. RESULTS: We report our initial experience with this device, which we used for univentricular bridging to total orthotopic cardiac transplantation in 3 infants. The device was inserted to support the left ventricle in two instances and to support the right heart in one. Successful bridging to transplantation was achieved in 2 infants for periods of 2 and 7 weeks. CONCLUSIONS: Our experience demonstrates the feasibility of univentricular mechanical support followed by successful cardiac transplantation in infants and newborns.

Aortic Valve Stenosis↗

PubMed1998

Thoracic epidural anesthesia does not affect functional recovery from myocardial stunning in sevoflurane-anesthetized dogs.

OBJECTIVE: A beneficial effect of thoracic epidural anesthesia (TEA) on recovery from myocardial stunning was previously shown in awake dogs. The aim of this study was to investigate the effects of TEA on recovery from myocardial stunning in sevoflurane-anesthetized dogs. DESIGN: Randomized animal study. SETTING: Animal laboratory of a university hospital. PARTICIPANTS: Chronically instrumented mongrel dogs. INTERVENTIONS: Six dogs were chronically instrumented for measurement of hemodynamics and myocardial wall thickening fraction (WTF). The following experiments were performed on separate days in a crossover fashion: (1) 10 minutes of ischemia of the left anterior descending (LAD) coronary artery during sevoflurane anesthesia without TEA and (2) 10 minutes of ischemia during sevoflurane anesthesia with TEA. MEASUREMENTS AND MAIN RESULTS: WTF was measured awake (baseline) and at predetermined time points until complete recovery of myocardial function occurred. Induction of anesthesia led to a decrease of WTF compared with baseline. Induction of ischemia led to a further decrease of WTF to negative values, which returned to positive values within the first minute of reperfusion. There were no differences between the two experimental conditions at any of the time points measured. In awake dogs, TEA improved the recovery from myocardial stunning compared with the control experiment. There was no difference between conscious dogs with TEA or sevoflurane-anesthetized dogs with or without TEA. CONCLUSION: TEA has no additional protective effect on the recovery of WTF during sevoflurane anesthesia.

Anesthesia, Epidural↗

PubMed1998

Effect of platelet inhibitors on thromboembolism after implantation of a Novacor N100--preliminary results.

BACKGROUND: Left-ventricular assist device implantation (LVAD) is still associated with thromboembolism as the optimal anticoagulation is still unclear. We report on the effects of adding platelet inhibitors to our anticoagulation regimen in our Novacor LVAD program. METHODS: Oral platelet aggregation inhibitors (aspirin 330 mg + dipyridamole 75 mg, three times per day) were added to the heparin/phenprocoumon treatment in 9 patients starting on postoperative day 3 to 7 (group A). Of the previous 41 patients, the last 20 patients served as a control group (group B), to reduce any learning curve effect. RESULTS: The mean interval of mechanical support between the two groups was comparable (group A vs B: 148 +/- 127 vs 104 +/- 61 days, n.s.). Accordingly, the cumulative support was much lower in group A (1051 days) as compared to group B (2091 days). In group B, 10 patients (50%) developed clinically evident thromboembolism. The number of events ranged from 1 to 10 (mean 1.4 +/- 2.3), with a total of 32. With addition of platelet inhibitors, the incidence of cerebral embolism dramatically dropped, as only one patient presented with transient ischemic attacks in group A (p < 0.05). Thoracic bleeding as defined by excessive drainage losses requiring redo thoracotomy did not increase (group A vs B: 22% vs 20%, n.s.). CONCLUSION: Addition of platelet inhibitors to heparin/phenprocoumon effectively prevents thromboembolism. However, platelet inhibitors should be postponed until sufficient hemostasis is achieved, since too early administration is associated with an increased risk of bleeding.

Anticoagulants↗

PubMed1998

Left ventricular pseudoaneurysm in a patient with Dressler's syndrome after myocardial infarction.

Successful recanalisation of the left anterior descending coronary artery was performed in a 51 year old man who was admitted two weeks after acute anterior myocardial infarction. Fourteen days later, the patient developed Dressler's syndrome with cardiac tamponade, which was immediately punctured. Sternotomy was performed after two weeks because of progressive haemodynamic deterioration, and fibrinous masses were removed from the pericardium. The patient recovered but two weeks later echocardiography showed a perforation of the left ventricular free wall and formation of a pseudoaneurysm. Intensive monitoring showed significant enlargement of the pseudoaneurysm, which was subsequently resected. This case demonstrates that dangerous formation of a pseudoaneurysm can occur not only during the first days of acute myocardial infarction but also after weeks in patients suffering from non-infectious pericarditis caused by Dressler's syndrome. Although the incidence of Dressler's syndrome is declining, patients should be monitored carefully for several weeks, especially by echocardiography.

Aneurysm, False↗