Biomedical subjects

Roland Hetzer

Publications and source records attributed to Roland Hetzer.

At least 163 records · Page 9Linked to original sources

PubMed2002

Tissue-engineering bioreactors: a new combined cell-seeding and perfusion system for vascular tissue engineering.

One approach to the tissue engineering of vascular structures is to develop in vitro conditions in order ultimately to fabricate functional vascular tissues before final implantation. In our experiment, we aimed to develop a new combined cell seeding and perfusion system that provides sterile conditions during cell seeding and biomechanical stimuli in order to fabricate autologous human vascular tissue in vitro. The cell seeding and perfusion system is made of Plexiglas and is completely transparent (Berlin Heart, Berlin, Germany; University Hospital Benjamin Franklin, Berlin, Germany). The whole system consists of a cell seeding chamber that can be incorporated into the perfusion system and an air-driven respirator pump connected to the bioreactor. The cell culture medium continuously circulates through a closed-loop system. We thus developed a cell seeding device for static and dynamic seeding of vascular cells onto a polymeric vascular scaffold and a closed-loop perfused bioreactor for long-term vascular conditioning. The cell seeding chamber can be easily connected to the bioreactor, which combines continuous, pulsatile perfusion and mechanical stimulation to the tissue-engineered conduit. Adjusting the stroke volume, the stroke rate, and the inspiration/expiration time of the ventilator allows various pulsatile flows and different levels of pressure. The whole system is a highly isolated cell culture setting, which provides a high level of sterility and a gas supply and fits into a standard humidified incubator. The device can be sterilized by ethylene oxide and assembled with a standard screwdriver. Our newly developed combination of a cell seeding and conditioning device provides sterile conditions and biodynamic stimuli for controlled tissue development and in vitro conditioning of an autologous tissue-engineered vessel.

Bioreactors↗

PubMed2002

Hemostatic activation and inflammatory response during cardiopulmonary bypass: impact of heparin management.

BACKGROUND: Cardiac surgery involving cardiopulmonary bypass (CPB) leads to fulminant activation of the hemostatic-inflammatory system. The authors hypothesized that heparin concentration-based anticoagulation management compared with activated clotting time-based heparin management during CPB leads to more effective attenuation of hemostatic activation and inflammatory response. In a randomized prospective study, the authors compared the influence of anticoagulation with a heparin concentration-based system (Hepcon HMS; Medtronic, Minneapolis, MN) to that of activated clotting time-based management on the activation of the hemostatic-inflammatory system during CPB. METHODS: Two hundred elective patients (100 in each group) undergoing standard cardiac surgery in normothermia were enrolled. No antifibrinolytic agents or aprotinin and no heparin-coated CPB systems were used. Samples were collected after administration of the heparin bolus before initiation of CPB and after conclusion of CPB before protamine infusion. RESULTS: There were no differences in the pre-CPB values between both groups. After CPB there were significantly higher concentrations ( < 0.05) for heparin and a significant reduction in thrombin generation (25.2 +/- 21.0 SD vs. 34.6 +/- 25.1), d-dimers (1.94 +/- 1.74 SD vs. 2.58 +/- 2.1 SD), and neutrophil elastase (715.5 +/- 412 SD vs. 856.8 +/- 428 SD), and a trend toward lower beta-thromboglobulin, C5b-9, and soluble P-selectin in the Hepcon HMS group. There were no differences in the post-CPB values for platelet count, adenosine diphosphate-stimulated platelet aggregation, antithrombin III, soluble fibrin, Factor XIIa, or postoperative blood loss. CONCLUSION: Compared with heparin management with the activated clotting time, heparin concentration-based anticoagulation management during CPB leads to a significant reduction of thrombin generation, fibrinolysis, and neutrophil activation, whereas there is no difference in the effect on platelet activation. The generation of fibrin even in the presence of high heparin concentrations most likely has to be attributed to the reduced antithrombin III concentrations or reduced inhibition of clot-bound thrombin. Therefore, in addition to maintenance of higher heparin concentrations, monitoring and substitution of antithrombin III should be considered to ensure more efficient antithrombin activity during CPB.

Adult↗

PubMed2002

Intravascular ultrasound assessment of longitudinal plaque distribution patterns in patients with angiographically silent coronary artery disease after heart transplantation.

AIMS: The purpose of this three-dimensional intracoronary ultrasound (ICUS) study was to assess longitudinal plaque distribution patterns in patients with angiographically silent coronary artery disease (CAD) after heart transplantation (HTX). METHODS AND RESULTS: Out of 334 patients without diameter stenosis >/=25% determined by coronary angiography, 321 underwent successful three-dimensional ICUS (30 MHz) of the left main coronary artery (LMCA) and all segments of the left anterior descending coronary artery (LAD). Early plaque formation was found in 296 patients (92.2%). Single (focal CAD, n = 65) or multiple (polyfocal CAD, n = 77), discrete coronary lesions were found in 142 patients and continuous plaque formation of at least one entire coronary segment (diffuse CAD) in 154 patients. Using multivariate regression analysis, male sex (P = 0.01), increasing post-transplantation time (P = 0.003) and increasing donor age (P = 0.001) were independent clinical predictors for diffuse CAD. Both focal and diffuse CAD most frequently affected the proximal LAD (88% compared with 89.6%, NS). The mean intimal index of each LAD segment was significantly higher in patients with diffuse CAD (P < 0.001) and showed a proximal-to-distal decline in patients with focal/polyfocal (LMCA, 10.1 +/- 14.3, LAD-6, 30.1 +/- 17.4%, LAD-7, 16.3 +/- 14.1%, LAD-8, 4.6 +/- 11.1%; P < 0.001) and diffuse (LMCA, 27.0 +/- 16.0, LAD-6, 47.8 +/- 16.1%, LAD-7, 41.9 +/- 14.5%, LAD-8, 24.9 +/- 23.3%; P < 0.01) CAD. CONCLUSION: Evaluation of longitudinal plaque distribution after HTX by three-dimensional ICUS revealed a time-dependent increase in the incidence of diffuse CAD and a proximal-to-distal decline in frequency and magnitude of early plaque formation.

Cohort Studies↗

PubMed2002

Bronchiolitis obliterans syndrome in lung transplant recipients: use of spirometrically gated CT.

PURPOSE: To assess the potential use of spirometrically gated lung computed tomographic (CT) findings in the diagnosis of bronchiolitis obliterans syndrome after lung transplantation. MATERIALS AND METHODS: Forty-nine lung transplant recipients were examined at least 8 months after surgery with spirometrically gated thin-section CT of the lung. In addition to visual signs of small-airway disease at CT, mean lung attenuation and the SD were numerically determined and compared with the results of lung function testing at the time of the CT examination and 1 year later by using factorial analysis of variance. RESULTS: Mean lung attenuation was significantly lower in patients who developed bronchiolitis obliterans syndrome within 1 year after the CT study (-837 HU +/- 3) than in patients with persistent normal lung function (-812 HU +/- 3, P <.001). With an optimal threshold, sensitivity was 69%, specificity was 71%, and accuracy was 84%. Visual analysis did not significantly contribute to the prognostic power of CT. CONCLUSION: Spirometrically gated CT measurements of lung attenuation can be used to predict the onset of bronchiolitis obliterans syndrome after lung transplantation.

Adult↗

PubMed2002

Huge pulmonary arteriovenous fistula: diagnosis and treatment and an unusual complication of embolization.

We report the case of a 42-year-old woman with Rendu-Osler-Weber syndrome (hereditary hemorrhagic telangiectasia) and a huge pulmonary arteriovenous fistula that involved the entire right middle lobe. She had a history of dyspnea and intermittent atrial flutter for 6 months. A chest radiograph showed a discrete shadowing of the middle part of the right lung. Arteriovenous fistula was suspected based on the echocardiographic finding of immediate bubble detection in the left atrium on introducing echocardiographic contrast medium into the venous system. Atrial shunt was excluded. Angiography revealed a huge pulmonary arteriovenous fistula in the entire middle lobe of the right lung. A trial of interventional embolization was performed, but the size of the fistula made it impossible to achieve complete closure of all segmental fistulas. Furthermore, the patient complained of unusual, severe chest pain after implantation of the first coil, so that the coil had to be removed. Therefore the patient underwent surgical resection of the entire right middle lobe and the upper part of the right lower lobe. Anatomy was clearly delineated and all connecting vessels were suture-closed, but both lungs showed diffuse microscopic superficial pulmonary arteriovenous fistulas, which were too small to be detected by angiography and which were also partly closed. The postoperative course was uneventful: the patient recovered completely, she no longer had shortness of breath, and blood gas analysis showed normal P(aO)(2). It is not clear whether the patient's improved physical performance will last, because the development of diffuse microscopic arteriovenous fistulas bilaterally in the lungs is not predictable. Therefore close follow-up is necessary and in the case of recurrence (ie, enlargement of the existing small fistulas), early interventional embolization should be performed.

Adult↗

PubMed2002

Clinical and echocardiographic features in patients with dilated cardiomyopathy: wave intensity and diastolic abnormality analysis.

OBJECTIVE: The pathophysiology of dilated cardiomyopathy is not fully understood, and among the problems which need to be solved is the lack of an adequate classification which could help to predict the survival of patients in the end stage of the disease. The criteria used today, based on clinical symptoms and invasive and noninvasive assessment of the heart function, are far from satisfactory. Estimation of maximal oxygen consumption is a time-consuming procedure and more descriptive of the global cardiopulmonary situation rather than being able to provide specific answers. Loading conditions seem to be the key to the problem. The state of vascular resistance and systolic performance of the heart can be defined using the method known as "wave intensity" (WI), which represents the relation of the pressure estimated noninvasively to the flow inside the vessel. This study presents first experiences with wave intensity in the Deutsches Herzzentrum Berlin in patients suffering from end-stage dilated cardiomyopathy (DCM), a group of ambulatory patients after heart transplantation (HTx), and in healthy volunteers. The study was performed in supine and upright position. PATIENTS: Out of 182 patients waiting for transplantation, thirty-one (17%) ambulatory patients suffering from dilated cardiomyopathy comprised the first group (Group A). Their mean age was 53 +/- 14.2 years and 16 were men. Maximum MV O2 was 16.1 (+/- 4.57) mg/kg. Mean PAP and capillary pressure were 26.1 (+/- 11.91) and 16.8 (+/- 9.81) mmHg, respectively. Cardiac index was 2.3 (+/- 0.58) l/min/m2. The second group (Group B) consisted of 56 ambulatory patients after heart transplantation (mean 3.8 +/- 3.35 years) who did not suffer from rejection. Their mean age was 49.9 +/- 15.18 years and 47 were men. Normal sinus rhythm was an inclusion criterion for the study. The control group consisted of 15 healthy volunteers with a mean age of 35 +/- 12 years and 2 were men. METHOD: Real time wave intensity (WI), Doppler mitral filling and noninvasive cardiac output were recorded and analyzed using the ALOKA 5.500 machine equipped with a wave intensity real time analysis system. Wave intensity was defined noninvasively as the product of delta U and delta V where delta U was vascular diameter change (representing pressure change) and delta V was the velocity inside the vessel. The measurements were done in real time during constant short time intervals. The WI data were obtained from the right common carotid artery in all patients. RESULTS: The 1st and 2nd WI peaks were significantly lower in supine position in the DCM group and rose significantly in upright position when compared to the data from patients after transplantation and volunteers. The values of 1st and 2nd peak in supine position in DCM were respectively 4606 (+/- 2283) and 1483 (+/- 675) and upright 1st and 2nd were 5405 (+/- 3432) and 202 (+/- 1726). The values of 1st and 2nd peak in the Tx group were significantly higher at rest: 10,743 (+/- 6290) and 3195 (+/- 2127), respectively, and were not significantly lower after upright maneuver. The highest values of both products (1st and 2nd) of WI were observed in healthy volunteers 14,632 (+/- 6293) and 14,153 (+/- 6969) and were significantly higher when compared to the DCM group (p = 0.01). Cardiac output in the supine position was significantly lower in the DCM patients and fell after position was changed to erect. In the Tx group, cardiac output was normal at rest and didn't fall significantly in the upright position. The DCM and transplant patients showed abnormalities in diastolic heart function after changing to the erect position (restrictive pattern of mitral filling); however, more severe filling abnormalities were found in the DCM patients. CONCLUSION: Our results demonstrate that patients suffering from DCM are less tolerant of arthostatic stress than patients after heart transplantation. The slight increase in wave intensity in the DCM group hints at stronger activation of autonomic vascular control, leading to a stiffening in the arterial system, which possibly protects the central nervous system from hypoperfusion. The diastolic alteration was probably the response of diseased myocardium to increased requirements of the peripheral system after changing the position of the patients. This diastolic alteration, although less pronounced, was noticed in the transplanted group, but was not seen in healthy individuals. Therefore, we conclude that wave intensity is a new, powerful marker providing information not only about left ventricular systolic function but also about mechanoelastic properties of the arterial system integrated with elastic properties of the myocardium.

Adult↗

PubMed1999

Pulsatile pediatric ventricular assist devices: Current results for bridge to transplantation.

While pulsatile ventricular assist devices have gained widespread use in adult patients awaiting heart transplantation, only very limited experience with these devices exists in the pediatric population. In the past mostly non-pulsatile systems such as ECMO have been used to support pediatric patients with heart failure for very limited periods of time. Only recently have miniaturized pulsatile devices became available. This article describes the technical characteristics of these devices which have been implanted at the Deutsches Herzzentrum Berlin since 1992. The Berlin Heart assist device has since been used in 34 children between the ages of 6 days and 16 years. We report our strategy in patient selection, perioperative care and subsequent heart transplantation. The current literature on mechanical circulatory support in children is reviewed. Copyright 1999 by W.B. Saunders Company

Journal Article↗

PubMedDate not supplied

Myocardial rewarming mirrors intraoperative mammary artery graft function.

BACKGROUND: The internal mammary artery (IMA) bypass graft provides a satisfactorily long-lasting blood supply to the myocardium. However, its initial flow capacity can be insufficient with subsequent regional myocardial ischemia. We evaluated a method to assess the IMA graft function intraoperatively. METHODS: Twenty-five patients with three-vessel coronary artery disease underwent coronary artery bypass grafting on cardiopulmonary bypass. The in situ IMA was grafted to the left anterior descending coronary artery (LAD) in combination with two saphenous vein grafts to the left circumflex and right coronary artery. Distal anastomoses were performed during cold intermittent blood cardioplegia. After unclamping of the aorta and of the grafted IMA, the temperature at the cardiac anterior and posterior side was measured during the first 5 minutes of warm reperfusion. RESULTS: A sufficient IMA graft function was expressed by a typical rise in temperature: the cardiac anterior and posterior sides showed a parabolic and exponential course, respectively. The rewarming velocity expressed as the first derivative of temperature over time led to a sharp and early peak for the anterior side, and a smaller and delayed peak for the posterior side. Insufficient IMA graft function could be recognized by an atypical temperature course. CONCLUSIONS: Temperature measurement of the heart during warm reperfusion after hypothermic cardioplegia can help to assess the effectiveness of the IMA-LAD graft function.

Coronary Angiography↗

PubMedDate not supplied

Application of stereolithography for scaffold fabrication for tissue engineered heart valves.

A crucial factor in tissue engineering of heart valves is the functional and physiologic scaffold design. In our current experiment, we describe a new fabrication technique for heart valve scaffolds, derived from x-ray computed tomography data linked to the rapid prototyping technique of stereolithography. To recreate the complex anatomic structure of a human pulmonary and aortic homograft, we have used stereolithographic models derived from x-ray computed tomography and specific software (CP, Aachen, Germany). These stereolithographic models were used to generate biocompatible and biodegradable heart valve scaffolds by a thermal processing technique. The scaffold forming polymer was a thermoplastic elastomer, a poly-4-hydroxybutyrate (P4HB) and a polyhydroxyoctanoate (PHOH) (Tepha, Inc., Cambridge, MA). We fabricated one human aortic root scaffold and one pulmonary heart valve scaffold. Analysis of the heart valve included functional testing in a pulsatile bioreactor under subphysiological and supraphysiological flow and pressure conditions. Using stereolithography, we were able to fabricate plastic models with accurate anatomy of a human valvular homograft. Moreover, we fabricated heart valve scaffolds with a physiologic valve design, which included the sinus of Valsalva, and that resembled our reconstructed aortic root and pulmonary valve. One advantage of P4HB and PHOH was the ability to mold a complete trileaflet heart valve scaffold from a stereolithographic model without the need for suturing. The heart valves were tested in a pulsatile bioreactor, and it was noted that the leaflets opened and closed synchronously under subphysiological and supraphysiological flow conditions. Our preliminary results suggest that the reproduction of complex anatomic structures by rapid prototyping techniques may be useful to fabricate custom made polymeric scaffolds for the tissue engineering of heart valves.

Bioprosthesis↗

PubMedDate not supplied

Mitral annulus after mitral repair: geometry and dynamics.

The study of systolic changes in both the inflow and outflow of the left ventricle after mitral repair elucidates the geometric characteristics after surgery. The study included eight normal subjects and six patients after mitral repair without a prosthesis. The left ventricular (LV) base, consisting of both mitral valve annulus (MVA) and left ventricular outflow tract (LVOT) orifice, was reconstructed from magnetic resonance images. The angle between the planes of the MVA and LV base (MB angle), and the proportionate share of the LVOT at the LV base were calculated. After mitral repair, both the MVA and LV base became almost normal in size, showing flexible change (i.e., contraction and dorsiflexion) in the MVA and contraction of the LV base in systole. Compared with the normal heart at 100 ms delay from the electrocardiogram R wave, the hearts of the patients at the same phase had a mean 1.05 cm2 larger LVOT orifice, resulting in a mean 8.0 degree larger MB angle. Furthermore, the LVOT orifice occupied a mean of 49.5% of the LV base (41.9% in normal subjects). We hypothesize that the higher MB angle at early systole may weaken the tension of the chordae of the anterior mitral leaflet.

Adult↗

PubMedDate not supplied

Development of a database of patients supported by ventricular assist devices.

An increase in the number of patients with end stage heart failure is leading to increased use of ventricular assist devices (VAD). However, sometimes the optimal time point for implantation of left ventricular or biventricular support remains unclear. Data analysis using an electronic database may help to make the decision making process more precise and thus improve outcome. However, it is not easy to find a balance between sufficient comprehensiveness of the data, which are selected from a huge amount of available information, and practicability of database maintenance and data analysis. We developed the Assist Database based on Access for Windows. The Assist Database consists of five main parts: (1) demographic and admission data, diagnosis, goal, and type of VAD; (2) preoperative period; (3) postoperative period up to 30 days; (4) follow-up period; and (5) statistical evaluation. The preoperative and postoperative parts include hemodynamic data; ventilatory support; laboratory results; results from echocardiographic, neurologic, pathologic, and other examinations; medication; and complications. The follow-up part documents readmissions, complications, and outcome. From April 1987 to October 2002, eight different types of VAD were implanted in 654 patients in our institution. Their data were retrospectively added to the Assist Database using medical records and different previously used electronic databases. Since the Assist Database came into routine use, it has been supplied daily with selected data of current patients. On the data entry level, the data arising from medical records are entered either manually via standard forms or automatically from other electronic documentation systems used in our hospital in routine patient care to collect laboratory results, demographic data, blood transfusion data, and operative data and from electronic patient charts via interfaces. The structure of the database is designed to facilitate the data analysis level. The database presented is one of three databases united to form a network. The structure of the Assist Database facilitates comprehensive, time saving data collection, which allows different online data analyses. These analyses may affect the decision making process and thus improve outcome. However, achieving a balance between the volume of available information, the time consumed, and the relevance of the data for further analysis remains difficult. The Assist Database should include information relevant for the decision making process and for the prediction of outcome. In particular, data collection should be focused on patients' preoperative condition and on postoperative organ function and quality of life. Further, different databases (for patients with congestive heart failure, assist device patients, and transplanted patients) should be unified to form a network to avoid the repeated collection of identical data, to save time, and to increase the quality of analysis. In the long-term, multicenter use of the Assist Database could be considered.

Data Collection↗

PubMedDate not supplied

Effects of basic fibroblast growth factor and transforming growth factor-beta on maturation of human pediatric aortic cell culture for tissue engineering of cardiovascular structures.

Optimal in vitro conditions are necessary for the development of a strong, well structured, and functional tissue engineered cardiovascular structure eventually designed for implantation. To further optimize in vitro conditions for cell proliferation and extracellular matrix formation in tissue engineering of cardiovascular structures, in this study, ascorbic acid and growth factors as additives to standard cell culture medium were evaluated for their effect on tissue development in vitro. Biodegradable polymer patches [polyglycolic acid (PGA) coated with poly-4-hydroxybutyrate (P4HB)] were seeded with human pediatric aortic cells and cultured for 7 and 28 days. Group A was cultured with standard medium (DMEM with 10% fetal calf serum and 1% antibiotics) supplemented with ascorbic acid; group B was cultured with standard medium plus ascorbic acid and basic fibroblast growth factor (bFGF); group C was cultured with standard medium adding ascorbic acid and transforming growth factor (TGF). Analysis of the cell seeded polymer constructs included DNA assay, collagen assay, and histologic and immunohistochemical examination for cell proliferation and collagen formation. After 7 and 28 days of culture, group B and group C showed a significantly higher DNA content compared with group A. The addition of bFGF (group B) led to a markedly higher collagen synthesis after 28 days of culture compared with the additives in groups C and A. The histologic and immunohistochemical examination also revealed a more dense, organized tissue development with pronounced matrix protein formation in the tissue engineered structures in group B after 28 days of culture. When seeded on to the polymeric scaffold, human vascular cells proliferate and form organized cell tissue after 28 days of culture. The addition of bFGF and ascorbic acid to the standard medium enhances cell proliferation and collagen synthesis on the biodegradable polymer, which leads to the formation of more mature, well organized tissue engineered structures.

Aorta↗

PubMedDate not supplied

Executive cognitive dysfunction without stroke after long-term mechanical circulatory support.

Among patients who receive heart transplantation (HTx) after long-term mechanical circulatory support (MCS), some show executive cognitive dysfunction without a history of stroke. Fifty HTx patients (19 patients on MCS for longer than 3 months before HTx and 31 patients without MCS as control group) were enrolled in the study. All subjects were men aged between 20 and 59 years without a history of stroke. Patients with MCS were divided into two groups: the AH-Thr group (n = 11), in which thrombus was detected in the left ventricular assist device (LVAD) and quickly removed (mean 3.3 times); and the AH group (n = 8), in which there was no detectable thrombus in the LVAD. The Trail Making Test (TMT) and the Wisconsin Card Sorting Test (WCST) were administered. The AH-Thr group showed poorer cognitive performance both in the TMT part B, with longer completion time (p < 0.05 versus the other two groups), and in the WCST, with more perseverative errors (p < 0.001 versus the other two groups). These data indicate that patients in the AH-Thr group showed executive cognitive dysfunction in set-shifting ability, suggesting frontal lobe damage. The conditions that facilitate thrombus formation in the LVAD may induce executive cognitive dysfunction without stroke.

Adult↗

PubMedDate not supplied

Short-term culture of human neonatal myofibroblasts seeded using a novel three-dimensional rotary seeding device.

A crucial factor in the tissue engineering of heart valves is an effective cell seeding with uniform cell distribution on biodegradable scaffolds to eventually form functional tissue constructs in vitro. In our laboratory, we developed a new cell-seeding device for optimal cell distribution for tissue-engineered heart valve constructs. In the present study, we developed a new cell-seeding device made of acrylic glass that is completely transparent (University Hospital Benjamin Franklin, Berlin, Germany). The polymeric heart valve scaffold is fixed in a small-volume, cylindrical cell-seeding chamber, and is surrounded by optimal cell suspension. The cell-seeding chamber is placed in a clear acrylic bowl so that it can be rotated in all directions to provide optimal cell distribution to all areas of the heart valve construct. We thus developed a highly isolated cell-seeding device that is driven by an independently developed rotating machine consisting of two independent motors (University Hospital Benjamin Franklin, Berlin, Germany). The whole system provides a high level of sterility and fits into a humidified incubator. Our newly developed cell-seeding device enables sterile conditions and optimal cell distribution for the controlled fabrication of autologous tissue-engineered heart valve constructs.

Biocompatible Materials↗

PubMedDate not supplied

Transfusion-free cardiac surgery with cardiopulmonary bypass in a 2.2-kg neonate.

Particularly in neonates, complex cardiac surgery employing cardiopulmonary bypass normally requires the transfusion of autologous blood components. This is predominately caused by the relatively high priming volume of the circuit with subsequent extreme hemodilution. We report on a synoptic approach to avoiding transfusions in a 2.2 kg neonate with scheduled for correction of an intracardiac total anomalous pulmonary venous connection to the coronary sinus and a persistent foramen ovale. In this patient with a preoperative hemoglobin value of 16.5 g/dL, minimization of the cardiopulmonary bypass circuit, adjustment of the perfusion technique and strict reduction of blood sampling resulted in complete avoidance of transfusions during the entire course of the operation while maintaining safe hemoglobin levels, which never fell below a concentration of 8 g/mL.

Blood Transfusion, Autologous↗

PubMedDate not supplied

Repair of ALCAPA in a 4-kg patient followed by successful weaning and "off-pump" explantation of an apical venting pulsatile LVAD.

Even in infants and small children, ventricular assist devices have an emerging role in the treatment of congenital and postcardiotomy heart failure. Extracorporeal pneumatic pulsatile devices are considered the strategy of choice if long-lasting bridge to recovery or transplantation is expected. However, complete explantation of the device may be complicated by hemorrhage and subsequent transfusions due to the establishment of CPB. The present case demonstrates successful weaning and complete removal of an apical venting pulsatile LVAD in a 4-kg infant without the employment of CPB.

Abnormalities, Multiple↗

PubMedDate not supplied

Different hemodynamic stress of the ascending aorta wall in patients with bicuspid and tricuspid aortic valve.

It is unclear whether ascending aorta dilation in patients with bicuspid aortic valve is caused by abnormal hemodynamics or by a common developmental defect of the aortic valve and aortic wall. We performed an echocardiographic study to examine the differences in hemodynamic stress at the ascending aorta in patients with bicuspid and tricuspid aortic valve. We studied prospectively 58 consecutive patients referred for preoperative echocardiographic examination with aortic valve stenosis and either bicuspid or tricuspid valve and an ascending aortic diameter of </=4.5 cm. Echocardiographic examination was performed from the parasternal long-axis view using ALOKA SDD 5.500 (Aloka, Tokyo) with 3.5 MHz probe. With aortic wall tissue Doppler imaging we obtained wall motion velocity patterns from the anterolateral and posteromedial region of the ascending aorta. The tissue Doppler examination showed a significantly higher peak systolic wall velocity of the anterolateral region of the ascending aorta in patients with bicuspid aortic valve (12.2 +/- 4.3 cm/sec vs. 8.8 +/- 2.6 cm/sec, p = 0.047). We conclude that in patients with bicuspid aortic valve and aortic valve stenosis the anterolateral region of the ascending aorta is subject to greater hemodynamic stress than in patients with tricuspid aortic valve.

Aged↗

PubMedDate not supplied

Cardiopulmonary bypass for complex cardiac surgery using bivalirudin anticoagulation in a patient with heparin antibodies.

BACKGROUND: The presence of antibodies directed against heparin necessitates the use of an alternative anticoagulant in patients undergoing cardiac surgery. Bivalirudin is a short-acting direct thrombin inhibitor that has been used successfully in routine cardiac surgical cases. Experience in complicated cases requiring extended cardiopulmonary bypass is limited, however. We report the successful use of bivalirudin in a patient who underwent complex cardiac surgery. METHOD: A 42-year-old patient with aortic regurgitation due to endocarditis who had heparin antibodies underwent a Ross procedure for aortic valve replacement using bivalirudin as anticoagulant during cardiopulmonary bypass (CPB). Bivalirudin was given with a bolus of 1 mg/kg and a continuous infusion of 2.5 mg/kg/hours during CPB. Monitoring of bivalirudin was performed using the ecarin clotting time (ECT). RESULTS: After 128 minutes of extracorporeal circulation, the patient was weaned from CPB without problems. After termination of CPB, modified ultrafiltration (MUF) was commenced. Perioperatively, six units of fresh frozen plasma were transfused. The 12-hour postoperative blood loss was 550 mL. The postoperative course was uneventful and the patient was discharged from hospital after 5 days. CONCLUSION: Bivalirudin can be safely used for anticoagulation during CPB even in complex cardiac surgery.

Adult↗