Search PubMed⌕ Search

Biomedical subjects

B Reichart

Publications and source records attributed to B Reichart.

At least 19 recordsLinked to original sources
PubMed2006

Fluorescent microspheres reveal different regional blood flow in hyperacutely rejected nontransgenic and hDAF pig hearts.

Classic features of hyperacute rejection show differential severity in the inner compared to the outer myocardium. In the present study, regional blood flow (RBF) measured by fluorescent microspheres served as a marker of the extent of hyperacute rejection. Using a working heart model, hearts of nontransgenic and hDAF transgenic pigs were perfused with human blood. Additionally, hDAF transgenic pig hearts were perfused with human blood containing GAS914 or the GPIIb/IIIa inhibitor tirofiban. Injections of fluorescent microspheres into the donor heart were performed in situ and during perfusion. Reference arterial blood samples were collected from the inferior aorta and the afterload line. Perfusion was terminated before hyperacutely rejected hearts failed to pump against the afterload column. RBF was determined in tissue samples of standardized areas of the left atrium and ventricle. Each specimen was divided into subepicardial and subendocardial tissue samples. Fluorescence intensity was measured using an automated luminescence spectrometer. At the end of perfusion with human blood, hyperacutely rejected nontransgenic pig hearts showed a higher RBF in the subendocardium. In hDAF-transgenic pig hearts perfused with unmodified human blood the subendocardial/subepicardial blood flow ratio changed in favor of the subepicardium. This ratio was not further improved by GAS914. In contrast, tirofiban was able to assimilate subepicardial and subendocardial blood flow. In conclusion, RBF of hyperacutely rejected pig hearts was inhomogeneous. Inhibition of complement activation improved the reduced subepicardial RBF, but depletion of antibodies had no positive effect. The ability of tirofiban to further increase subepicardial RBF affirms thrombosis of subepicardial veins as the defining characteristic of hyperacute rejection.

Acute Disease↗
PubMed2006

Seeding of human vascular cells onto small diameter polyurethane vascular grafts.

INTRODUCTION: Thrombogenicity of small diameter vascular prostheses might be reduced by complete coverage of the luminal surface with vascular cells. We investigated cell seeding on polyurethane vascular prostheses (PUVP). METHODS: 45 PUVP were divided into three groups of n = 15 each: Group A (diameter 20 mm, gamma-sterilized), Group B (diameter 4 mm, gamma-sterilized), and Group C (diameter 4 mm, ethylene oxid [Eto]-sterilized). Human smooth muscle cells (SMC), fibroblasts (FB), and endothelial cells (EC) were isolated from saphenous vein segments and expanded in culture. PUVPs were pre-seeded with a mixed culture of FBs and SMCs (mean 7.7 +/- 2.3 x 10(6) cells) followed by EC seeding (mean 4.4 +/- 0.9 x 10(6) cells). Seven days after cell seeding, PUVPs were perfused under a pulsatile flow. Flow definitions were as follows: adaption phase: low flow, resulting pressure: 60/30 mm Hg; high flow: resulting pressure: 160/50 mm Hg, lasting for 4 hours in all groups. Three subgroups were defined out of each group, differing in the perfusion strategy: high flow immediately, adaption phase of 15 minutes followed by high flow, and adaption phase of 30 minutes followed by high flow. Specimens were taken after each seeding procedure, prior to and after perfusion, and then examined using a scanning electron microscope (SEM) and immunohistochemical staining procedures. RESULTS: Pre-seeding with the mixed culture revealed a better initial adhesion in Groups A and B compared to group C (76% vs. 41%). In Groups A and B, EC seeding (adhesion 72%) resulted in a confluent EC layer. Immunohistochemical stainings were positive for collagen IV, laminin, CD31, and factor VIII, but negative for eNOS. In Group C, only isolated cells were found after each seeding procedure, which rounded up and vanished during the next days. When perfused with high-flow immediately, Group A and B prostheses revealed small defects (< 10% of the surface) of all cell layers. After perfusion with an adaption phase of 15 minutes only few defects were found within the EC layer with an intact basement membrane. An adaption phase of 30 minutes resulted in a confluent cell layer without significant cell defects. After perfusion, the endothelial cells also stained positive for eNOS. CONCLUSION: Seeding of a mixed culture consisting of FBs and SMC resulted in an excellent EC adhesion and resistance to shear stress. Cell attachment was better on gamma-sterilized PUVPs compared to Eto-sterilization. The cells obviously maintained their ability to adapt to shear stress.

Adaptation, Physiological↗
PubMed2006

The controversy of donor serum sodium levels in heart transplantation--a multicenter experience.

BACKGROUND: Elevated donor serum sodium is a phenomenon often encountered in the management of brain dead donors. The clinical relevance on recipient outcome is less examined. We investigated the impact of elevated donor serum sodium levels (DSL) on outcome after heart transplantation in 1800 heart transplantations. METHODS: Data was conducted in a retrospective analysis from 1989 until 2005. The transplantations were performed at three German heart transplant centers. The joined database included DSL at the time of organ procurement, recipient and donor age, ischemia time, primary graft failure and survival data. RESULTS: Mean DSL was 147.7 +/- 10.3 l/l (range 111 - 208 l/l). Recipients were divided into 4 groups with percentiles of 141, 147, and 154 l/l resulting in DSL of A: 135.8 +/- 4.4, B: 143.6 +/- 1.7, C: 149.7 +/- 1.9, and D: 161.3 +/- 7.7 l/l for the four quartiles. Primary graft failure occurred in 2.6 % of the patients with A: 2.8 %, B: 2.8 %, C: 3.7% and D: 1.4 % ( P = n.s.). Mean 5- and 10-year-survival rates were 70.9 % (57.6 %) with A: 71.1 % (53.86 %), B: 69.3 % (53.9 %), C: 72.7 % (61.0 %), D: 71.2 % (62.4 %), respectively ( P = n. s.). In a multivariate analysis a significant impact on postoperative results could be revealed for recipient age ( P = 0.002), ischemia time ( P = 0.002) and donor age ( P = 0.009). DSL were no individual risk factor in the multivariate analysis. CONCLUSION: There was no impact of donor serum sodium levels neither on early postoperative results, nor on long-term outcome indicating that cardiac allografts from donors with elevated sodium levels might be transplanted successfully, achieving favourable results.

Adolescent↗
PubMed2005

A low-flow adaptation phase improves shear-stress resistance of artificially seeded endothelial cells.

INTRODUCTION: The purpose of this study was to evaluate the effect of different adaptation phases on the shear-stress resistance of endothelial cells seeded artificially onto vascular prostheses and biological heart valves. MATERIAL AND METHODS: Human endothelial cells (EC), fibroblasts (FB), and smooth muscle cells (SMC) were isolated from vena saphena magna pieces and expanded in culture. Group A: 15 polyurethane vascular grafts (20 mm diameter) were seeded with FB and SMC (53 +/- 1.2 million cells), followed by EC seeding (39 +/- 0.9 million cells). Group B: eight stentless porcine valves (Freestyle, Medtronic, USA) were seeded with FB (68 +/- 1.5 million cells) and EC (42 +/- 1.1 million cells). Shear-stress testing was done under pulsatile flow (pulse rate: 80 pulses/min.). Adaptation phase: flow was set to 0.9 +/- 0.3 l/min (systolic pressure: 40 - 50 mm Hg). High flow was 3.2 +/- 0.6 l/min. (systolic pressure: 140 - 160 mm Hg) and lasted over four hours in all groups. The vascular grafts were divided into three groups (n = 5 each): group 1 (high flow immediately), group 2 (adaptation phase of 15 minutes), and group 3 (adaptation phase of 30 minutes). The valves either were given high flow immediately (n = 4) or had an adaptation phase of 30 minutes (n = 4). Specimens were obtained after cell seeding, before, and after perfusion. RESULTS: A confluent EC layer was achieved on all grafts. After perfusion without adaptation, large defects within the cell layer were found. No FB and SMC were seen at the bottom of these defects. In group B, the defects were largest on the ventricular surface of the leaflets. After an adaptation phase of 15 minutes in group A, only a few defects within the EC layer were detected with a still confluent FB and SMC. After a 30-minute adaptation phase defects within the EC layer were very rare and no interruption of the underlying FB and SMC layer was seen. Immunohistochemical staining for factor VIII and CD31 proved the EC to be viable and staining for collagen IV and laminin revealed the formation of a basement membrane. After perfusion, the specimen also stained positive for eNOS. CONCLUSION: An adaptation phase of 30 minutes proved to be sufficient to allow artificially seeded endothelial cells to adapt to shear stress. The formation of a basement membrane was of great importance for the maintenance of a confluent EC layer.

Adaptation, Physiological↗
PubMed2005

Results of pediatric cardiac transplantation -- long-term results of a 15-year experience.

INTRODUCTION: Heart transplantation (HTx) has increasingly become a therapeutic option for end-stage heart failure of any origin in children. Short- and mid-term results are promising. However, long-term outcome has been a matter of concern because of acute or chronic rejection and side effects of immunosuppression. We performed a retrospective study of up to 15-years of follow-up on this patient entity. METHODS: Between 1988 and 2004, 58 HTx were performed in 55 children (cardiomyopathy (DCM) 32, congenital heart disease (CHD) 23, Re-HTx 3). Mean age was 9.1 +/- 7.2 years (4 days - 17.9 years). Twenty-nine patients had a total of 51 previous operations. RESULTS: Operative mortality was 4/58 (6.8 %) due to primary graft failure. Late mortality was 7/54 (12.1 %) due to acute rejection (2), pneumonia (2), intracranial hemorrhage (1), suicide (1) and lymphoma (1). Mean follow-up was 5.2 +/- 4.2 years. One-, 5-, and 10-year survival was 86 %, 80 % and 80 %, respectively, and improved significantly after 1995 (92 % and 92 %; p = 0.04). Survival was comparable for DCM and CHD patients (1-year: 88 % vs. 82 %; p = 0.19; 5-years: 84 % vs. 77 %; p = 0.12). Three patients with therapy resistant rejection and assisted circulation required retransplantation and are alive. Freedom from acute rejection was 46 % with primary cyclosporine immunosuppression and 63 % with tacrolimus. Ninety-eight percent of the survivors are at home and in excellent cardiac condition. CONCLUSION: Pediatric heart transplantation is a curative treatment for DCM and CHD with excellent clinical mid-term results. However, further follow-up is necessary to evaluate long-term side effects of immunosuppressants. Donor shortage remains a problem.

Cardiomyopathy, Dilated↗
PubMed2005

Minimally invasive off-pump pulmonary vein isolation to treat paroxysmal atrial fibrillation.

BACKGROUND: Minimally invasive off-pump pulmonary vein isolation to cure paroxysmal atrial fibrillation (PAF) may be an alternative to percutaneous catheter-based procedures. METHODS: Three patients with highly symptomatic lone PAF refractory to medical treatment and having undergone unsuccessful catheter-based ablation underwent pulmonary vein isolation using the Cardioblate BP device with a minimally invasive approach. RESULTS: There were no complications and all patients were discharged in sinus rhythm. Mean ablation time per lesion was 15.2 sec and mean operation time was 118 min. CONCLUSIONS: Irrigated bipolar radiofrequency ablation of the pulmonary veins is safe and can be performed off-pump in a minimally invasive manner.

Atrial Fibrillation↗
PubMed2005

Human herpesvirus 6 in bronchalveolar lavage fluid after lung transplantation: a risk factor for bronchiolitis obliterans syndrome?

Bronchiolitis obliterans syndrome (BOS) is the limiting factor to long-term survival after lung transplantation. Previous studies suggested respiratory viral tract infections are associated with the development of BOS. To identify the impact of virus detection in bronchoalveolar lavage (BAL) fluid, we analyzed BAL samples from 87 consecutive lung transplant recipients for human herpesvirus (HHV)-6, Epstein-Barr virus, Herpes simplex virus 1/2, Cytomegalovirus, respiratory syncytical virus and adenovirus by PCR. Acute rejection, BOS and death were recorded for a mean follow-up time of 3.27 +/- 0.47 years. Results of PCR analysis and other potential risk factors were entered into a Cox regression analysis of BOS predictors and death. Only acute rejection was a distinct risk factor for BOS of all stages, death and death from BOS. HHV-6 was detected in 20 patients. Univariate and multivariate analysis revealed that HHV-6 was associated with an increased risk to develop BOS > orb = stage 1 and death, separate from the risk attributable to acute rejection. Identification of HHV-6 DNA in BAL fluid is a potential risk factor for BOS. Our results warrant further studies to elucidate a possible causal link between HHV-6 and BOS.

Adenoviridae Infections↗
PubMed2004

Laparoscopic diaphragmatic plication: long-term results of a novel surgical technique for postoperative phrenic nerve palsy.

BACKGROUND: Paralysis of the diaphragm is a severe complication of cardiothoracic surgery carrying significant morbidity and mortality. This study demonstrates a novel minimally invasive technique for treatment of phrenic nerve injuries presenting with symptomatic eventration of the diaphragm. It also presents long-term results of three patients treated with this operation. METHODS: Chest x-ray proved eventration of the left diaphragm in all patients. Two patients required treatment due to prolonged respirator therapy/assisted ventilation for 4 weeks after cardiac surgery. One patient suffered from progressive dyspnea caused by increasing left-sided diaphragmatic elevation and underwent surgery 2 years after cardiac surgery. In all cases, a minimally invasive abdominal approach was chosen. During surgery the dome of the diaphragm was pulled down via three percutaneously inserted retention stitches. This resulted in two or three folds of the diaphragm located within the abdomen. These diaphragmatic folds were subsequently tightened using 12 to 15 unresorbable sutures with extracorporally prepared knots. Surgical as well as long-term follow-up results are presented of all patients and a review of the current literature is provided. RESULTS: Mean operating time was 203 min; mean intraoperative blood loss was 130 ml. No major complications occurred during surgery or the postoperative period. At a median follow-up of 72 months no recurrence was observed. CONCLUSIONS: Laparoscopic diaphragmatic plication provides excellent relief of symptoms caused by diaphragmatic paralysis. There is no perioperative morbidity, and hospital stay is short. The laparoscopic approach, therefore, is an attractive surgical alternative for the treatment of phrenic nerve palsy and should be considered in all suitable patients.

Aged↗
PubMed2003

[Surgical treatment of aortic valve disease in old age].

In terms of long-term survival and quality of life, excellent results with aortic valve replacement (AVR) can also be achieved in patients older than 70 years of age. An indication for this procedure is given in symptomatic patients with significant aortic valve stenosis, patients with severe acute aortic insufficiency (AI), those with signs of cardiac insufficiency but still normal left ventricular function, and asymptomatic AI patients with an ejection fraction of less than 50% and/or an end-diastolic LV diameter (EDD) of more than 75 mm or an end-systolic diameter (ESD) of more than 55 mm. Many patients with a heart defect in need of surgical treatment also have CAD as well, in which case a bypass should be performed at the same time. For AVR, both mechanical and biological prostheses are available, the latter being regarded as the method of choice in patients aged over 70. The mechanical variant requires life-long anticoagulation therapy with phenprocoumon.

Age Factors↗
PubMed2003

[Leiomyosarcoma of the heart--interdisciplinary therapeutic approach of systemic chemotherapy and subsequent heart transplantation].

HISTORY AND ADMISSION FINDINGS: A 35-year-old man reported progressive exercise dyspnea, decreased exercise tolerance and weight loss of 10 kg in 2 months. Imaging tests demonstrated a tumor of maximally 7 cm diameter in the region of the left atrium. Histologically it was a poorly differentiated leiomyosarcoma G 3, which could not be completely resected (R 2 resection). SUBSEQUENT INVESTIGATION: Six weeks after surgical resection a rapidly growing tumor, maximally 7.5 cm in diameter, was visualized at the right lateral region of the left atrium. It filled it almost completely and extended via the right upper pulmonary vein to the right hilus. TREATMENT AND COURSE: As part of a multimodal therapeutic approach he was given 6 cycles of chemotherapy (doxorubicin and ifosfamide), bringing about significant reduction of the tumor size. The tumor was then completely resected, followed by an orthotopic heart transplantation with right pneumonectomy. The resected surgical specimen indicated complete remission, no vital tumor cells being demonstrated. No tumor recurrence or distal metastasis was seen during a follow-up period of 36 months. The patient died from right heart failure with advanced pulmonary hypertension 45 months after the diagnosis had first been made, 37 months after the cardiac transplantation.

Adult↗
PubMed2003

[Prevention of early graft occlusion after coronary bypass grafting by post-operative reduction of plasma fibrinogen by H.E.L.P. apheresis. First evaluation of 12 patients treated during our study (44 bypasses)].

BACKGROUND: Early graft occlusion is a known complication after CABG (Coronary Artery Bypass Grafting). The thromboembolic closure of the bypass occurs at a frequency of 5-15%, depending on the implemented vessel (arterial or venous graft). Fibrinogen as a substrate of thrombus formation plays a major role in both primary and secondary haemostasis. The operative trauma triggers the acute phase-response and also activates the clotting process. This leads to high fibrinogen levels of up to 600 mg/dl postoperatively, providing an impaired haemorrheological pattern which promotes thrombus formation. In a prospective pilot-study we examined whether drastic postoperative lowering of fibrinogen by H.E.L.P.-(Heparin-mediated Extracorporeal LDL-/Fibrinogen Precipitation) apheresis can prevent early graft vessel closure in patients undergoing CABG. METHODS: For the purpose of this study 12 male patients (mean age 60+/-5.8 years) who underwent multivessel CABG were recruited between 12/2000 and 2/2002 according to a GCP approved protocol. The postoperative fibrinogen levels of the patients were monitored and H.E.L.P. apheresis was applied when plasma fibrinogen levels exceeded >350 mg/dl on day 1 and >250 mg/dl every following day up to day 8 after the operation. Pre- and post apheresis blood samples were obtained and reduction of plasma fibrinogen, LDL-Cholesterol and CRP were determined. Coronary angiography was performed within the 9th-16th postoperative day. To investigate the long term outcome a second coronary angiography was performed half a year after the operation. RESULTS: A total of 44 bypass grafts (23 arterial; 21 vein grafts) were implemented in 12 patients (mean 3.6/patient) and a total of 66 H.E.L.P.-Apherses from day 1-8 were postoperatively applied (mean 5.5/patient). Fibrinogen levels were lowered from a maximum on day 2 of 447+/-112.2 mg/dl (pre-apheresis) to a minimum on day 8 of 228+/-46.2 mg/dl (pre-apheresis) demonstrating a reduction of 50%. Per single treatment the fibrinogen was lowered from 357+/-93 mg/dl (pre-apheresis) to 157+/-46 mg/dl (post apheresis); reduction: 55%. Coronary angiography revealed graft patency in 43 of 44 grafts (97.7% patency). The one occluded bypass was an Y-graft to a diagonal branch less than 1mm in diameter. No bleeding or H.E.L.P. related complications were observed.Up to now 7 of 12 patients underwent the second coronary angiography according to the study protocol. Apart from the already immediately postoperatively occluded Y-graft no new bypass-occlusion was revealed. CONCLUSIONS: Early and extensive reduction of postoperatively elevated plasma fibrinogen levels by H.E.L.P. apheresis seems to be an efficient and safe therapeutic approach for preventing early graft occlusion in patients undergoing multivessel CABG.

Anticoagulants↗
PubMed2003

Surgical treatment of permanent atrial fibrillation using microwave energy ablation: a prospective randomized clinical trial.

OBJECTIVE: Radiofrequency or the use of microwave energy in combination with atrial size reduction during open heart surgery have been reported to be effective in up to 75% in the treatment of permanent atrial fibrillation. However, no data from prospective randomized trials using microwave energy are available. METHODS: Forty-three patients with permanent atrial fibrillation undergoing open-heart surgery were randomly stratified into treatment group receiving microwave ablation and atrial size reduction (n=24) or control group (n=19). Patients in either group were treated with amiodarone or sotalol for 3 months if sinus rhythm or any atrioventricular rhythm was successfully restored. Follow-up time points were at 3, 6 and 12 month after surgery. RESULTS: In the treatment group 22 out of 24 patients (91,7%) were successfully converted to sinus rhythm by using intraoperative microwave ablation therapy whereas only six out of 19 (31.5%) patients converted to sinus rhythm directly after surgery. At 12-month follow-up there were still a significantly higher percentage of patients in the treatment group free from atrial fibrillation when compared to control (80 vs. 33.3%, P=0.036). CONCLUSION: The preliminary data from this first prospectively randomized trial indicate that microwave ablation combined with atrial size reduction is a safe and highly efficient treatment in permanent atrial fibrillation.

Aged↗
PubMed2003

Myoblasts for survive 16 weeks after intracardiac transfer and start differentiation.

INTRODUCTION: Skeletal myoblasts have been shown to survive transfer into myocardial scar tissue. The purpose of this study was to investigate differentiation after intramyocardial transplantation. Additionally, we evaluated an intravital fluorescence dye. MATERIALS AND METHODS: Skeletal myoblasts were harvested from 8 male inbred Lewis rats and expanded in culture. For each transplantation planned, 10(6) cells were trypsinized and incubated for three minutes with 2 ml of buffered PKH-26 solution (Sigma, St. Louis). This dye was integrated into the cell membrane. After washing three times, the cells were plated again for two more days. The cells were then transplanted into the hearts of 60 female Lewis-rats, mean weight 380 g (260 - 450 g). At implantation, 10(6) cells suspended in 100 microliters were injected into the apex region of the left ventricle. 12 animals served as the control group with only cell medium injected. Animals were sacrificed after 1, 2, 6, 8, 12, and 16 weeks (n = 10 each). The hearts were explanted and serial frozen sections of the hearts were prepared for detecting labeled cells. Sections with labeled cells were stained immunohistochemically for Myo D1 (myogenic origin), n-cam (early myotubes), desmin (muscular filament), myosin light chain (muscular contractile protein), and connexin 43 (tight junction). RESULTS: Cell labeling was successful in all cases. After two days, the myoblasts had recovered from the staining procedure. The fluorescing dye, however, was only rarely transmitted by cell division. Marked cells were found in the intercellular spaces between the cardiac myofibers in at least 8 animals from each group. No fibrotic reaction or inflammation was seen surrounding the transplanted cells. Up to 6 weeks after implantation, the cells stained positive for n-cam and Myo D1, and particularly for desmin. More n-cam positive cells were found than labeled cells, indicating cell division after the cell transfer. Two animals suffered sudden death after a follow-up time of 8 and 10 weeks, which was possibly due to cardiac arrhythmia. After 8 weeks, the cells formed conglomerates and stained positive for desmin, myosin light chain, and connexin 43. The cells were not structurally integrated into the recipient myocardial tissue, however. CONCLUSIONS: Myoblasts divided further after transplantation into rat myocardium. Positive staining for desmin demonstrated the development of myofibers. Starting at 8 weeks after transplantation, the cells started differentiation without reaching structural integration during follow-up. Labeling the cells with PKH-26 proved to be a reliable method to detect the cells.

Animals↗
PubMed2003

Neurological and neuropsychological examination and outcome after use of an intra-aortic filter device during cardiac surgery.

Cerebral embolization of particles after cardiac surgery is frequently associated with neurological deficits. Aortic crossclamp manipulation seems to be the most significant cause of emboli release during cardiac surgery. The goal of this study was to demonstrate whether the use of an intra-aortic filter device has an effect on the magnet resonance imaging (MRI) and functional neurological outcome. Twenty-four patients undergoing cardiosurgical procedures using cardiopulmonary bypass (CPB) were selected: coronary artery bypass graft (CABG) surgery (n = 17), aortic valve replacement (AVR) surgery (n = 4) or combined procedures (n = 3). Patients were evaluated by diffusion weighted MRI of the brain, neurological examination and neuropsychological assessment regarding alertness as well as divided and selective attention before and five to seven days after surgery. The patients were divided into two groups. In group I, 12 patients received a filter through a modified 24 F arterial cannula immediately before the aortic crossclamp was released. Filters remained in the aorta until CPB was discontinued. Intraoperatively, bilateral middle cerebral artery transcranial Doppler (TCD) was monitored at baseline, at the beginning of CPB, at a timepoint when the aorta was crossclamped, when the filter was inserted and while the crossclamp was switched to partial clamping until the CPB was discontinued. TCD was used for detection of microembolic signals (MES). The captured material in the filter was examined histologically. Twelve patients served as controls without aortic filtration (group II). The MRI of the brain did not show any diffusion alterations in either group before or after surgery. No patient developed a focal neurological deficit or stroke. Intraoperative quantitative MES detection revealed a four to tenfold increase in patients of group I compared with group II (5-6 versus 0.5-1 MES/min) during the filter dwell time. There was no consistent pattern regarding the neurobehavioural sequelae. Filters showed arteriosclerotic debris in 75% of the patients. The use of the intra-aortic filter device did not show a positive effect on neurological, neuroradiographical and neuropsychological outcomes. The increase of the MES rate in group I patients may be due to microbubbles generated as microcavitations by the filter or the aortic filter cannula. The intra-aortic filter was able to capture atheromatous material in 75% of the patients.

Aorta, Thoracic↗
PubMed2003

Homografts: a review.

Since their introduction into clinical practice in 1965 homografts have become established in clinical routine. The storing and sterilization procedures have been improved over time. Long-term results showed that homografts had a superior durability compared to xenogenic biological prostheses. Approximately 40% were still in place 20 years after implantation in aortic position. Their low rate of thromboembolic events made a life-time anticoagulative therapy unnecessary and their hemodynamics were superior to all other heart valve prostheses. There exist two implantation techniques, subcoronary or mini-root, both technically more demanding compared with implantation of stented valve prostheses. When using the subcoronary technique, the valve is suspended into the aortic root leaving the coronary arteries untouched. The success of this technique, however, depends on the relation of the recipients aortic root and the implanted valve. The mini-root technique requires reimplantation of the coronary arteries but left the morphology of the valve and its root unchanged. Especially in patients with endocarditis, the mini-root technique offered the advantage of allowing for excision of all affected tissue with subsequent replacement by the homograft. The Ross-procedure uses the patient's own pulmonary valve as aortic valve substitute with implantation of a homograft in pulmonary position. This proved to be advantageous in children, since in these patients the degeneration of an aortic homograft was faster compared to an older population. This was explained by the recipient's immunologic response to the graft which was more pronounced in younger patients. The advantages of homografts with regards to hemodynamics and thromboembolic risk make them a good alternative to mechanical prostheses in younger, active patients. In very young patients, a Ross-procedure was shown to be superior to aortic homografts due to slower degeneration of the autograft. The decision to use a homograft must be made individually according to the patients demands.

Heart Diseases↗