Olaf Elert

Prevention of sternal dehiscence and infection in high-risk patients: a prospective randomized multicenter trial.

BACKGROUND One factor for the development of sternal wound infection (SWI) is bony instability after sternotomy. This study compares two surgical techniques with respect to the occurrence of SWI in patients with an increased risk. METHODS In this multicenter study, 815 consecutive patients with an increased risk for SWI were prospectively randomly assigned to a conventional osteosynthesis (transsternal or peristernal wiring; n = 440) or to an osteosynthesis with additional lateral reinforcement (Robicsek; n = 375). Primary endpoints were the rate of sternal dehiscence as well as the occurrence of superficial sternal wound infections and deep sternal wound infections. RESULTS Both groups were comparable concerning preoperative and intraoperative variables. The rate of sternal dehiscence, superficial sternal wound infections, and deep sternal wound infections (conventional technique 2.5%, 3.4%, 2.5%; and Robicsek 3.7%, 5.6%, 3.7%) did not differ between the groups. Logistic regression analysis found independent risk factors for the development of sternal dehiscence: body mass indes greater than 30 kg/m(2) (odds ratio [OR]: 2.9; p = 0.05), New York Heart Association class more than III (OR: 2.4; p = 0.07), impaired renal function (OR: 3.9; p = 0.01), peripheral arterial disease (OR: 3.6; p = 0.001), immunosuppressant state (OR: 3.3; p = 0.001), sternal closure performed by an assistant doctor (OR: 2.5, p = 0.004), postoperative bleeding (OR: 4.2; p = 0.03), transfusion of more than 5 red blood units (OR: 3.7, p = 0.01), reexploration for bleeding (OR: 6.9, p = 0.001), and postoperative delirium (OR: 3.5, p = 0.01). There was an inverse relation between the numbers of wires and DSWI in patients with conventional sternal closure (p = 0.008). CONCLUSIONS In patients with an increased risk for sternal instability and wound infection after cardiac surgery, sternal reinforcement according to the technique described by Robicsek did not reduce this complication.

Selective loss of regulatory T cells in thymomas.

Myasthenia gravis (MG) is the prime autoimmune manifestation of thymomas. We investigated the generation of T cells with a regulatory phenotype (TR) in thymomas with and without associated MG. In patients with MG(+) thymomas, maturation and export of TR cells but not of other T‐cell subsets was significantly reduced. We conclude that imbalance between effector and regulatory T cells in thymomas may be involved in modulation of onset and/or severity of MG. Ann Neurol 2004;56:901–904

Changes in coagulation and fibrinolytic parameters caused by extracorporeal circulation.

SummaryDuring cardiopulmonary bypass (CPB) mechanical stress and the contact of blood with artificial surfaces lead to the activation of pro- and anticoagulant systems and the complement cascade, and to changes in cellular components. This phenomenon causes the “postperfusion-syndrome”, with leukocytosis, increased capillary permeability, accumulation of interstitial fluid, and organ dysfunction. In this study, we focused on the influence of the extracorporeal circulation, sternotomy, and heparin administration on the activation of coagulation and fibrinolysis. In 15 patients we investigated coagulation parameters before, during and post CPB, i.e., fibrinogen, antithrombin (AT) III, thrombin-antithrombin complex (TAT), prothrombin fragments F1 + 2 (F1 + 2), factor (F) XIIa, tissue factor (TF), and parameters of the fibrinolytic system, i.e., plasmin-antiplasmin-complex (PAP), D-dimer, tissueplasminogen-activator (tPA), urokinase-type plasminogen activator (uPA), and plasminogen-activator inhibitor type 1 (PAI 1). The results demonstrate distinct alterations in the above mentioned parameters. Despite administration of a high dose of heparin (activated clotting time [ACT] > 450s) combined with a low dose of aprotinin, activation of the coagulation and fibrinolytic pathways was observed. We found this activation was mainly caused by CPB and not by sternotomy. The activation of coagulation was due to foreign surface contact (F XII ⇒ F XIIa) as well as to an effect of tissue factor release in the late phase of CPB. The enhanced fibrinolytic activity during CPB was, at least in part, caused by tPA and was followed by PAI 1 release.

A clinical chameleon: postoperative hypoparathyroidism

BackgroundAbout 1,200 patients per year develop postoperative hypoparathyroidism alone in Germany. Many of those patients may be misdiagnosed as the symptoms of this disease may vary and can be atypical.Patient/resultsAs an example, we describe the first known case of an elderly patient with a long history of seizures as a complication of an undiagnosed chronic hypoparathyroidism after surgery of a pT4-esophageal carcinoma. The 63-year-old male patient underwent laryngo–hypopharyngo–esophagectomy with gastric transposition and partial thyroid resection for a proximal esophageal carcinoma in 1994. About half a year later, the patient developed for the first time a convulsive syncope. Misleading diagnoses were for years suspected metastasis formation and a dumping syndrome. The general physician of the patient called him the epilepsy man, while no cause of the seizures were found. More than a decade of years later, when the correct diagnosis was made, finally by determination of parathyroid hormone levels, the seizures of the patient were completely eliminated by calcium supplementation therapy. The patient’s quality of life improved clearly in the following time.ConclusionIt is essential to consider chronic hypoparathyroidism in the differential diagnosis of patients with hypocalcemia who have undergone extended neck and proximal esophageal surgery before. In addition to that, it is mandatory to autotransplant parathyroids during the initial procedure which might be accidentally removed during surgery and to monitor parathyroid function in each patient in the further course postoperatively.

Cardiac allograft vasculopathy after cardiac transplantation and hormone therapy : Positive effects?

Background. There is a great deal of controversy surrounding the issue of hormone replacement therapy after transplantation. The question whether or not this therapy has effects in cardiac allograft vasculopathy (CAV), the Achilles heel of cardiac transplantation or other unique aspects of allograft function is still unknown. Methods. We investigated the long-term effect of 17β-estradiol as well as phytoestrogen Coumestrol, a synthetically produced phytoestrogen, on the development of CAV and the degree of fibrosis in an ovariectomized female heterotopic chronic allograft model (LEW-F344). Results. We found that, 150 days after transplantation, no significant effect of estrogen application on intimal thickening of coronary arteries was observed. 17β-estradiol and phytoestrogen Coumestrol did significantly reduce the perivascular immune reaction. However, the immune effect had no consequence on the intensity of CAV. Although neither 17β-estradiol nor phytoestrogen Coumestrol revealed a positive effect on CAV, the group of animals treated with 17β-estradiol showed the highest decline in heart function and the most distinct fibrosis. Conclusions. 17β-estradiol does not affect CAV positively, but worsens cardiac allograft function and leads to increased fibrosis. This is the first study showing a negative effect of 17-β-estradiol after heart transplantation in the long term.

Heterotopic Rat Heart Transplantation (Lewis to F344): Early ICAM-1 Expression After 8 Hours of Cold Ischemia

BACKGROUND Primary graft dysfunction is a still poorly understood complication after cardiac transplantation. Ischemia/reperfusion injury contributes to different disorders resulting in impaired graft function. METHODS In a heterotopic rat heart transplantation model we extended graft ischemic time up to 8 hours. RESULTS Using immunohistochemistry we detected an up to 4-fold increase in intracellular adhesion molecule-1 (ICAM-1) expression during 4 hours of reperfusion, independent of ischemic time (30-minute ischemia: 7.65 +/- 2.15 without reperfusion, 19.46 +/- 4.6 after 4-hour reperfusion; 240-minute ischemia: 5.6 +/- 1.99 and 22.3 +/- 3.77; 480-minute ischemia: 3.7 +/- 1.56 and 13.1 +/- 2.2). Eight-hour ischemic allografts had an increase in CD8-positive cells (1.37 +/- 0.5 and 2.3 +/- 0.77) and a significant increase in MHC II expression (11.48 +/- 2.1 and 18.27 +/- 1.34) during 4 hours of reperfusion. CONCLUSIONS We hypothesize that these findings reflect an early inflammatory reaction in the allograft possibly triggered by oxidative stress. During therapeutic interventions, both of these pathways must be considered.

The effectiveness of a motivation programme for lifestyle change in the course of aortocoronary bypass graft surgery

Objective: To evaluate the effectiveness of a motivation programme the motivation for lifestyle change in patients was measured before and after coronary artery bypass graft (CABG) surgery by comparing a usual care group with a group attending a motivation programme. Design: Prospective controlled study. Setting: University hospital cardiothoracic surgery department. Subjects: One hundred and forty patients (mean age 64.9; SD 8.5 years) who had an elective CABG surgery. Interventions: Each patient was evaluated regarding his or her motivation for lifestyle change two days before and 10 days after CABG surgery. Between January and May 2002 patients in usual care were investigated as a control group (n=70). From January to May 2003 patients had the opportunity to take part in a motivation programme that was provided by a trained clinical psychologist (n = 70). The programme consists of both personalized single sessions and group lectures. Measures: A 30-item questionnaire measuring the six factors Vulnerability, Intention, Social expectation, Outcome expectation, Self-efficacy expectation, and Perceived severity was developed. Results: ANOVA procedures with repeated measurements indicate significant effects in terms of higher motivation for lifestyle change in the treatment group in Vulnerability (F(1, 138) = 4.04; P=0.04), Intention (F(1, 138) = 19.81; P<0.001), Social expectation (F(1, 138)=21.97; P<0.001), Outcome expectation (F(1, 138) =17.95; P<0.001), and Self-efficacy expectation (F(1, 138) =14.31; P<0.001). Conclusions: This motivation programme performed in a cardiac surgery hospital after CABG may increase the motivation for a positive lifestyle change.

Effects of the propofol combination anesthesia on the intrinsic blood-clotting system.

Fat emulsions can cause changes in blood-clotting and fibrinolysis. The aim of this study was to examine the relation between the use of the short-acting hypnotic propofol and alteration of the blood clotting system. In a double-blind randomized study, 36 patients with an aortocoronary bypass operation were given either midazolam/fentanyl or propofol/alfentanil. Eleven blood samples were taken at fixed times pre-, intra- and postoperatively to determine changes caused by the anesthetic agents on the hemostaseologic parameters during the whole operation. Perioperative blood pressures of both groups were measured at seven fixed points. From the beginning of the extracorporeal circulation (ECC) to the end of the operation, the measured values of the factor XIIa- and kallikrein-like activity in the propofol group were significantly higher than those of the midazolam group. Also the values of the kallikrein inhibition capacity and the indicators of fibrinolysis (t-PA and D-dimers) suggest a stronger activation of the contact phase at the start of the recirculation and as a result of it a stronger fibrinolysis within the propofol group. Besides, the hypotensive side-effect in the propofol group was evident in contrast to the midazolam group. With this investigation, a correlation between the application of propofol/alfentanil, contact phase activation with activation of the kallikrein-kinin-bradykinin system and the observed hypotension can be set up.

Microbubble Detektion während der extrakorporalen Zirkulation

ZusammenfassungWährend der extrakorporalen Zirkulation (EKZ) besteht durch die mechanische Oxygenierung des Blutes stets das Risiko von Gas-Embolien für den Patienten. Die Detektion von Microbubbles ist während der EKZ mit verschiedenartigen Methoden möglich. Doppler-Ultraschall kann als eine nicht invasive Methode eingesetzt werden um freie Gas-Embolien in der arteriellen Linie der Herz-Lungen-Maschine zu verifizieren.Die vorliegenden Messungen wurden an sechzehn Patienten während einer aorto-koronaren bypass-Operation vorgenommen.Der Aufbau der Herz-Lungen-Maschine bestand aus einer Stöckert® (Stöckert-Shiley, FRG) Rollerpumpe, einem Maxima® (Medtronic, FRG) Membranoxygenator und einem 40 μm Filter in der arteriellen Linie.Zur Microbubble Detektion wurde ein „Cardiovascular micro bubble detector” CMD 10® (Hatteland Instrumentering) eingesetzt. Die Doppler-Sonde war an der arteriellen Linie angebracht. In Zeitabständen von jeweils einer Minute wurden alle gemessenen Bubbles gezählt und der Größe nach 10 Levels zugeteilt. Die Anzahl der Bubbles wurde als Mittelwert±Standardabweichung zu definierten Zeitpunkten in der EKZ ausgedrückt.Während der EKZ erschien die höchste Anzahl an Bubbles in Level 1 entsprechend einer Größe von 10–19 μm. Es waren so gut wie keine Bubbles ab Level 5 entsprechend der Größen über 50 μm nachweisbar. Nach einem Peak der Embolierate bei Beginn der EKZ bestand nur eine geringe Embolierate nach dem Abklemmen der Aorta während einer moderaten Hypothermie. Beim Aufwärmen jedoch stieg die Emboliefrequenz auf 40 bis 300 Counts/min an.Die hier vorgestellte Methode einer semiautomatischen quantitativen und qualitativen Bubble Detektion zu standardisierten Zeitpunkten im Verlauf der EKZ stellt eine geeignete Kontrolle der Embolierate während der EKZ und somit auch zum Vergleich der Embolieraten verschiedener EKZ-Systeme dar.SummaryDuring extracorporeal circulation (ECC) the mechanically oxygenated blood always carries the risk of possible introduction of gas emboli into the patient. Detection of microbubbles during extracorporeal circulation is possible by means of different techniques. Doppler ultrasound can be used as an noninvasive method to detect free gas bubbles in the arterial line of the heart-lung-machine.The measurements were performed in 16 consecutive patients undergoing elective coronary artery bypass grafting.The experimental set up consisted of a StöckertTM (Stöckert-Shiley, FRG) heart-lung-machine with a roller pump, a MaximaTM (Medtronic, FRG) membrane oxygenator, and a 40 μm arterial filter.For microbubble detection, a “cardiovascular micro bubble detector” CMD 10TM (Hatteland Instrumentering) was used. The Doppler probe was attached to the arterial line. In one minute periods all bubbles were counted and divided into ten levels of bubble size. Bubble intensity was expressed as mean±SEM in defined times during ECC.During ECC most bubble intensity occurred at level L1, which corresponds to a bubble size of 10–19 μm. There was nearly no bubble activity at levels corresponding to bubble sizes greater than 50 μm. After an initial bubble release at the beginning of ECC, there was little gas bubble activity after aortic cross clamping during moderate hypothermia. However, during rewarming gas bubble release increased from an average of 40 counts/min to 300. The introduced method of using semiautomatic quantitative and qualitative bubble detection at standardized periods during ECC allows convenient bubble release control during ECC.

Sternal reconstruction with transverse plate fixation

Objectives: The management of sternal dehiscence associated with or without deep sternal wound infection (DSWI) constitutes in every single cases a challenging and controversial problem for a cardiothoracic surgeon. Over the years, quite an impressing array of various methods, materials and surgical techniques have been proposed to adress this complication of cardiac surgery, which occurs with an incidence of 1–8%. Methods: We report about our experience with transverse plate fixation of the sternum halves (TPF) with simplified bilateral pectoralis flap advancement in a series of 9 patients with DSWI, not in a one-step procedure, but after control of infection was achieved by V.A.C.® therapy. Results: All patients went on to complete bony union and wound healing was initially uneventful. The course in the follow-up period of 5 to 17 months was without pathological findings in seven patients. Two patients suffered from major complications, requiring repeat surgery. One thoracic wall hematoma (related to excessive anticoagulation), and one late wound infection occured 9 weeks after reconstruction, which made it necessary to remove the complete fixation system. Conclusion: The clear advantage of the method described are that it provides a very stsable reconstruction of the sternum after DSWI, even in the presence of a reduced or multi-fractured bone matrix, and, moreover, avoids complete mobilization of substernal adhesions and foreign material penetrating to the anterior mediastinum. Based on our experience, we will continue the use of TPF of the sternum combinded with bilateral pectoralis advancement in a selected group of patients.