Left anterior descending coronary artery: long-term angiographic results of CABG with endarterectomy.

AIM: The procedure of coronary bypass grafting (CABG) with coronary endarterectomy (CE) is controversial. However, in the setting of severely calcified coronary arteries CE may enable complete revascularization. Complete revascularization, especially of the left anterior descending artery (LAD), is important for long-term outcome. In this study we assessed long-term LAD graft patency and anterior wall function after CABG with CE of the LAD. METHODS: Between 1984 and 1992, 283 patients underwent CABG with CE of the LAD. In 50 patients (47 men), aged 59+/-7.6 (40-77), clinical reassessment and surveillance angiography were performed. In all patients complete revascularization had been achieved with 3.5+/-1 (1-5) grafts/patient with 1-3 CE/patient. The LAD was grafted either with a saphenous vein segment (N=38) or with left intern thoracic artery (N=12). A graft obstructed less than 50% in diameter was defined as patent. RESULTS: At follow-up 39 patients (78%) were in CCS class I/II and had improved significantly (P<0.000). Control angiography after 7.6+/-2.5 (3.5-11.7) years after CABG revealed a patent LAD graft in 30/50 patients (60%). Actuarial graft patency was 100%, 96%, and 56% after 2, 5, and 10 years and was lower in patients with diabetes (P=0.001). Deterioration of anterior wall motion was observed in 17 patients (34%) and was more frequent if anterior wall motion was preoperatively normal (P=0.002), irrespective of LAD graft patency. CONCLUSION: Clinical status and long-term graft patency of grafts on endarterectomized LAD is considerable. However, patients with preoperatively normal anterior wall function are at increased risk for myocardial damage in the long-term.

Successful single lung fontan operation in 2 children: case reports.

We report on 2 children, aged 3 and 4 years, with single ventricle physiology who underwent Fontan operation in the presence of a single right lung successfully with good midterm outcome. Therefore, the absence of one lung is not a contraindication for a Fontan palliation in selected patients with optimal hemodynamics.

Anatomical risk factors for mortality and cardiac morbidity after arterial switch operation.

BACKGROUND: The arterial switch operation (ASO) is the treatment of choice for transposition of the great arteries. METHODS: Anatomical risk factors on mortality and morbidity were analyzed retrospectively in 312 patients who underwent ASO between 1982 and 1997. RESULTS: Survival was 95%, 92%, and 92% after 30 days, 5, and 10 years, respectively. Operative survival improved after 1990 to 97% (p < 0.001). Risk factors for operative mortality were complex anatomy (p = 0.018), coronary anomalies (p = 0.008), and prolonged bypass time (p < 0.001). Determinants of late mortality were coronary distribution (p = 0.03), position of the great arteries (p = 0.0095), bypass time (p = 0.047), and aortic coarctation (p = 0.046). After a follow-up of 3.6 +/- 2.7 years (0.1 to 14.9 years), 98% had good left ventricle function, 94% were in sinus rhythm, 2.4% had moderate to severe pulmonary stenosis, 0.3% had significant aortic regurgitation, and 1% had coronary stenosis. Freedom from reoperation was 100%, 96%, and 94% after 1, 5, and 10 years, respectively. No preoperative anatomic parameter correlated with long-term morbidity. CONCLUSIONS: ASO can be performed with low operative mortality (< 5%) and long-term morbidity. Malformations associated with complex transposition of the great arteries influence early and late mortality.

Aortopexy reduces anastomosis stress after repair of coarctation.

Restenosis after repair of coarctation with hypoplastic distal aortic arch is an important complication. Complete removal of ductal tissue, resection of isthmus area, and side-to-side arterioplasty of the distal aortic arch leads to a wide distance between the aortic arch and descending aorta; therefore, the anastomosis may remain under tension, increasing risk of restenosis. To reduce the tension, aortopexy of the descending aorta was used. The operative technique and the results in 16 neonates and infants are presented.

Aortopexy in severe tracheal instability: short-term and long-term outcome in 29 infants and children.

BACKGROUND: Tracheal instability is a hazardous situation after operation for esophageal atresia. In cases with life-threatening apneas, aortopexy is a therapeutic option. To assess efficacy, short-term and long-term outcome was analyzed retrospectively. METHODS: Between 1985 and 2000, 29 patients (age, 1.5 months to 5.2 years) were operated on. A flaccid trachea after operation for esophageal atresia was the cause for life-threatening apneas in 27, and there was external vascular compression in 2 patients. The operative procedure consisted of ventropexy of the aortic arch to the sternum and ventral thoracic wall. RESULTS: There was neither early nor late mortality. A reversible lesion of the phrenic nerve was observed in 2 patients, a pneumothorax in 3, and secondary wound healing in 1. In all but 1 patient symptoms improved markedly or disappeared within days or within the first 3 months postoperatively. An increased susceptibility to respiratory infections was observed in long-term follow-up. CONCLUSIONS: Aortopexy can be performed with no mortality and low morbidity. Aortopexy is effective to prevent further life-threatening apneas, but does not prevent an increased susceptibility to respiratory infections.

Systemic right ventricular failure after atrial switch operation: midterm results of conversion into an arterial switch.

BACKGROUND: Failure of the systemic right ventricle after atrial switch operation can be treated by conversion into an arterial switch operation. METHODS: Four patients, age 38 to 59 months, presented with right ventricular failure after Senning operation and ventricular septal defect closure. One patient had elevated left ventricular pressure; in the other three patients the left ventricle was retrained to a left ventricular/right ventricular pressure ratio of 0.8 or greater by pulmonary artery banding in 12 to 24 months. RESULTS: Postoperative course after arterial switch operation was prolonged, but clinical condition was good at discharge. Fractional shortening ranged from 20% to 28%. Trace-to-moderate aortic regurgitation was present; only 1 patient had preserved sinus rhythm. After a mean follow-up of 43.5 months 1 patient had died due to left ventricular dysfunction. The survivors are in New York Heart Association functional class I to II. Fractional shortening has improved (29% to 37%); aortic regurgitation has not increased. No patient has undisturbed sinus rhythm. CONCLUSIONS: Conversion of an atrial into an arterial switch is an alternative to cardiac transplantation in childhood. However, the procedure is demanding. Long-term morbidity is caused by rhythm disturbances. Aortic valve performance and left ventricular function require close observation.

Closure of atrial septal defects via limited right anterolateral thoracotomy as a minimal invasive approach in female patients.

OBJECTIVE: The closure of atrial septal defects via sternotomy is a low-risk and high-benefit procedure. Limited right anterolateral thoracotomy is an alternative approach with regard to cosmetic aspects. However, it is discussed that a lateral approach is not appropriate for more complex lesions and is associated with an increased incidence of phrenic nerve damage. METHODS AND RESULTS: The perioperative and long-term outcomes (mean follow-up time: 73.2 months) of 87 female patients, mean age 20.4 years (range: 3-56 years), operated on for all types of atrial septal defects via limited right anterolateral thoracotomy between 1982 and 1993, were analysed retrospectively. Special features of the operation technique were a limited skin incision, protection of mammary gland tissue, prevention of phrenic nerve damage, and aortic cannulation in all patients. There were no intraoperative complications. Postoperative complications occurred in 12/87 patients including one rethoracotomy for postoperative bleeding and one late pericardial tamponade due to coumadine overdose. Follow-up was assessed by a survey obtained by the patients or their parents, and their family doctors in 79 patients (90.8%) Cardiac symptoms, mostly supraventricular arrhythmias, were observed in 13.9%. Echocardiography revealed mild tricuspid valve regurgitation (one patient) and mild mitral valve incompetence (one patient with ostium primum defect); there were no residual shunts. Cosmetic results were considered good and excellent in 87.3% and satisfactory in 8.9%. Three patients (3.8%) complained of a broad scar. Anaesthetic areas and optional scar pain were quite frequent (16.5%), whereas restriction of shoulder movement, breast asymmetry and scoliosis were rare. In summary, only one patient, suffering from intercostal neuralgia, would prefer sternotomy. CONCLUSION: Limited right anterolateral thoracotomy has a high cosmetic acceptance and was proven to be safe and effective for closure of any kind of atrial septal defects. Therefore, it is recommended as standard approach for atrial septal defects especially in female patients. reserved.

Pulmonary artery stenosis after systemic-to-pulmonary shunt operations.

OBJECTIVE: Systemic-to-pulmonary shunt operations are still required for palliation of certain congenital heart defects. The aim of this study was to analyze the incidence and etiology of the development of pulmonary artery stenosis after these procedures. METHODS AND RESULTS: Pre- and post-operative angiograms of 59 patients who underwent 54 peripheral and 12 central shunt operations were analyzed retrospectively. Patients without prior cardiovascular interventions (group I, n = 47) were differentiated from patients with prior interventions (group II, n = 12). In group I, all peripheral shunts were inserted contralaterally to the ductus arteriosus. Follow-up for all patients was 1.8 years (4 days-7.8 years). Pulmonary artery stenosis was diagnosed in 12/59 patients (20.3%, group I 12/47; group II 0) after a time interval of 4 days up to 5.3 years and only after Blalock-Taussig shunts (one classical, 11 modified) (12/40 = 30%). The stenoses were located ipsilaterally to the shunt in 7/12 and contralaterally in 5/12. Statistical analysis did not show any impact of age, weight, sex, shunt type or size, pulmonary artery diameters, Nakata and McGoon indices and prior interventions on the development of pulmonary artery stenosis. However, a patent ductus arteriosus and administration of Prostaglandin E1 had a significant impact on the development of pulmonary artery stenosis on the side of the ductus arteriosus. CONCLUSION: Pulmonary artery stenosis is not a rare event after systemic-to-pulmonary shunt operations. A patent ductus arteriosus with or without administration of Prostaglandin E1 is related to pulmonary artery stenosis on the side of the ductus arteriosus. Pulmonary artery stenosis on the side of a peripheral shunt may be caused by inappropriate surgical technique, increased intimal proliferation, or pulmonary artery kinking. Treatment depends on severity of cyanosis and on further surgical plans.

Anatomically positioned aorta ascending-descending bypass grafting via left posterolateral thoracotomy for reoperation of aortic coarctation.

OBJECTIVE: Operation for aortic recoarctation and/or residual hypoplastic arch represents a surgical challenge because of surrounding scar tissue in the coarctation area, hazard of spinal cord ischemia due to aortic cross-clamping, laceration of the recurrent nerve, and the choice of the best approach. We demonstrate the first results of an anatomically guided technique via the prior left thoracotomy approach without establishment of cardiopulmonary bypass. METHODS: Since 1989, five patients underwent anatomically positioned ascending-descending bypass grafting for treatment of recoarctation. Indication was a non-dilatable hypoplastic aortic arch segment; in two cases an additional isthmic restenosis was present. Inclusion criteria for our technique was an aorta ascending diameter large enough to allow partial clamping. Primary repair of aortic coarctation was end-to-end anastomosis in four patients and patch angioplasty in one. Mean age at primary repair was 5.5 years and at reoperation 16.1 years. Systolic pressure gradients at rest ranged from 35 to 70 mmHg; upper extremity hypertension was present in all patients. Operative technique consisted of performing a dacron or PTFE aorta ascending-descending bypass graft parallel to the aortic arch, size 18 or 20 mm in diameter, via the prior left thoracotomy. RESULTS: There were no intraoperative complications and all patients survived. Postoperative complications were left lung atelectasis with necessity of reintubation, pericardial effusion, and transient left diaphragm elevation, each in one patient. After 7-90 months all patients are free of symptoms, have normal blood pressure (with two patients being under anti-hypertensive medication), and have no echocardiographically measurable pressure gradients. CONCLUSIONS: Anatomically positioned aorta ascending-descending bypass grafting via the prior left posterolateral thoracotomy without cardiopulmonary bypass is a safe and efficient method for operation of complex recoarctation in patients with an acceptable size of the aorta ascendens.

Twenty years experience with pediatric pacing: epicardial and transvenous stimulation.

OBJECTIVE: Permanent cardiac pacing in children and adolescents is rare and often occurs by means of epicardial pacing. Based on two decades of experience, operative and postoperative data of patients with epicardial and transvenous pacing were analyzed retrospectively. METHODS: Between October 1979 and December 1998, 71 patients (mean age, 5.3+/-4.2, range, 1 day-16.2 years; mean body weight, 18+/-12; range, 8-56 kg) underwent permanent pacemaker implantation. Indications were sinus node dysfunction and atrio-ventricular block following surgery for congenital heart disease (69%), or congenital atrioventricular block (31%). Pacing was purely atrial (1.4%), purely ventricular (73%), ventricular with atrial synchronization (5. 6%), or atrioventricular synchronized (20%). Epicardial pacing was established in 49 (69%), transvenous in 22 (31%) patients. Follow-up was 3.4+/-3.8 years (epicardial) and 3.0+/-4.0 years (transvenous). RESULTS: Epicardial leads were implanted in younger patients (mean age: 4.5 vs. 7.0 years, P<0.05) and preferably after surgery induced atrioventricular block (78 vs. 46%, P<0.05). The youngest patient with transvenous pacing was 1.3 years old (weight, 8.5 kg). At implantation epicardial ventricular stimulation threshold at 1.0 ms was 1.07+/-0.46 vs. 0.53+/-0.31 V (transvenous) (P<0.05). The age-adjusted rate of lead-related reoperations was significantly higher in patients with epicardial leads (P<0.05), mainly due to increasing chronic stimulation thresholds resulting in early battery depletion. In three patients who received steroid-eluting epicardial leads initial low thresholds persisted after five month to one years. In two patients with recurrent epicardial threshold increase, steroid-eluting epicardial leads led to good acute and chronic thresholds after nine to 15 month. Two post-operative death (2.8%) were probably due to a dysfunction of the (epicardial) pacing system. CONCLUSIONS: Transvenous pacing in the pediatric population is associated with a lower acute stimulation threshold and a lower rate of lead-related complications. If epicardial pacing is necessary (e. g. small body weight, special intracardiac anatomy (e.g. Fontan), impossible access to superior caval vein), steroid-eluting leads may be considered.

Fibrin gel -- advantages of a new scaffold in cardiovascular tissue engineering.

OBJECTIVE: The field of tissue engineering deals with the creation of tissue structures based on patient cells. The scaffold plays a central role in the creation of 3-D structures in cardiovascular tissue engineering like small vessels or heart valve prosthesis. An ideal scaffold should have tissue-like mechanical properties and a complete immunologic integrity. As an alternative scaffold the use of fibrin gel was investigated. METHODS: Preliminary, the degradation of the fibrin gel was controlled by the supplementation of aprotinin to the culture medium. To prevent tissue from shrinking a mechanical fixation of the gel with 3-D microstructure culture plates and a chemical fixation with poly-L-lysine in different fixation techniques were studied. The thickness of the gel layer was changed from 1 to 3 mm. The tissue development was analysed by light, transmission and scanning electron microscopy. Collagen production was detected by the measurement of hydroxyproline. Injection molding techniques were designed for the formation of complex 3-D tissue structures. RESULTS: The best tissue development was observed at an aprotinin concentration of 20 microg per cc culture medium. The chemical border fixation of the gel by poly-L-lysine showed the best tissue development. Up to a thickness of 3 mm no nutrition problems were observed in the light and transmission electron microscopy. The molding of a simplified valve conduit was possible by the newly developed molding technique. CONCLUSION: Fibrin gel combines a number of important properties of an ideal scaffold. It can be produced as a complete autologous scaffold. It is moldable and degradation is controllable by the use of aprotinin.

Fulminant toxoplasmosis in a heart transplant recipient.

Toxoplasma gondii infections in heart transplant recipients emerge in most cases as newly acquired infections of the immunocompromised sero-negative patient from an exogenous source, usually the donor organ. We report on a 64-year-old heart transplant recipient who developed pneumonitis, myocarditis, and hyperacute encephalitis three weeks after transplantation. Histopathological examination of an endomyocardial biopsy revealed fulminant T. gondii infection. Although appropriate chemotherapy was administered immediately, the patient died the next day. Our case demonstrates that if a histological diagnosis is not rendered in time, fulminant toxoplasmosis may lead to a fatal outcome. In conclusion, a general screening of the donors and recipients for opportunistic infections, including toxoplasmosis, and an appropriate prophylaxis should always be considered.

Mechanical aortic and mitral valve replacement in infants and children.

BACKGROUND: The aim of this study was to evaluate early and late outcomes after mechanical systemic heart valve replacement in pediatric patients. METHODS: Between October 1981 and December 2003, 32 children (mean age 7.2 +/- 5.4 years; 4 months - 15.9 years) underwent mechanical mitral (MVR, n = 17), aortic (AVR, n = 13) or double valve replacement (DVR, n = 2) with St. Jude Medical valves. Twenty-two patients (69 %) had undergone previous cardiac surgery. Anticoagulation self-management was used since 1995. RESULTS: The operative mortality was 3.1 %. Perioperative complications were complete heart block (n = 5), ventricular fibrillation (n = 1) and myocardial infarction (n = 1) and were exclusively related to patients with MVR. Mean calculated valve size ratio (geometric prosthesis orifice area/normal valve size area) was 1.72 (1.07 - 2.85) for AVR and 1.4 (0.88 - 3.12) for MVR. Mean follow-up was 9.1 +/- 6.6 years (range 0.4 - 23.2 years, cumulative 283 patient-years). There were two late deaths in patients with MVR. Actuarial survival after 10 years was 93.8 %. Late complications were endocarditis (n = 2), minor hemorrhagic event (n = 1), and stroke (n = 1). Anticoagulation self-management is well accepted by all patients/parents. Overall 10-year freedom from any anticoagulation-related adverse event with phenprocoumon was 89.1 % (1.2 %/patient year). Nine patients required reoperations: redo-MVR (outgrowth of prostheses (n = 3), pannus overgrowth (n = 2), closure of paravalvular leak after AVR (n = 2), partial aortic valve thrombosis (n = 1) and redo-DVR (n = 1 for endocarditis). Freedom from reoperation after 10 years was 80.9 %. CONCLUSIONS: Mechanical valve prostheses are a valuable option for left-sided heart valve replacement in pediatric patients. Perioperative morbidity was exclusively related to patients with MVR. Oversizing was often possible to avoid early reoperation for outgrowth. The operative mortality and long-term morbidity are acceptable. Anticoagulation self-management is safe and well accepted.

Systemic mechanical heart valve replacement in children under 16 years of age.

UNLABELLED: We report the early and late outcome following left-sided mechanical heart valve replacement in children. Between 10/1981 and 02/2001, 27 children (13 male, mean age 7.2 +/- 5.2 years, range 0.53-15.7 years) underwent mechanical mitral (MVR 16), aortic (AVR 9) or double valve replacement (DVR 2) with St. Jude Medical valves. Eighteen children (66.7%) had undergone previous cardiac surgery. Valve disease was congenital in 23, due to endocarditis in 2 and rheumatic in 2 patients. Concomitant cardiac surgery was performed in 12 patients (44.4%). Operative mortality was 3.7% (1/27). Perioperative complications were complete heart block (5) and myocardial infarction (1). Mean follow-up was 6.5+/-5.9 years (range 0.4-19 years, total 169.9 patient-years). There was one valve-related late death due to mitral valve thrombosis without phenprocoumon. Actuarial survival after 1, 5 and 10 years was 93, 93 and 93%. Late complications included endocarditis (2), minor hemorrhagic event (1) and stroke (1). Overall 10-year freedom from any anticoagulation-related adverse event under phenprocoumon was 91% (1.3%/patient year). Eight patients required reoperations: re-MVR (5; outgrowth of the prostheses (3), pannus overgrowth (2)), closure of paravalvular leak after AVR (2), and re- DVR (1; endocarditis). Actuarial freedom from reoperation after 1, 5 and 10 years was 96, 88 and 76%. CONCLUSION: Mechanical valve prostheses are a valuable option for left-sided heart valve replacement in pediatric patients with good results. Operative mortality and the incidence of any valve-related events as endocarditis, reoperation, thromboembolism or anticoagulation related bleeding is acceptable.

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.

Experience with an adjustable pulmonary artery banding device in two cases: initial success--midterm failure.

Retraining of the left ventricle in congenitally corrected TGA or after Senning or Mustard operation is necessary when right-ventricular failure is developing and an arterial switch operation is indicated. As these hearts have little tolerance of marginal overbanding, a long-term adjustable pulmonary artery banding device would lower stress and risk of training. Although the inserted device (Osypka) allowed convenient intraoperative pressure ratio adjustment, mid-term adjustment failed due to dysfunction of the system.

Minimally invasive surgery for congenital heart defects in paediatric patients.

BACKGROUND: In selected cases, minimally-invasive approaches are favoured for the correction of congenital heart defects with regard to better cosmetic results. METHODS: Between July 1999 and April 2001, 25 children (9 male; mean age 5.8 +/- 4.1 years; mean weight 19.6 +/- 12.6 kg) were operated on using minimally invasive approaches. Diagnoses were: ASD (n = 19), VSD (n = 2), ostium primum defect (n = 3) and Tetralogy of Fallot (n = 1). Female patients with ASD underwent a limited right anterolateral thoracotomy. A ministernotomy was chosen in male patients, in patients under 6 months of age, and in patients with malformations other than ASD. Cannulation was always performed via the chest incision. RESULTS: There were no perioperative complications. Mean operation time was 3.23 +/- 0.89 h. Twelve patients were extubated immediately after surgery, mean ventilation time in the others was 12.1 +/- 11.7 h. Mean ICU stay and hospital stay were 1.5 +/- 0.75 days and 8.3 +/- 2.2 days, respectively. Follow-up (mean 4.8 +/- 4.6 months) was uneventful. CONCLUSIONS: Intracardiac repair of some congenital heart defects can be performed safely and effectively via minimally-invasive approaches. Indications are expanding towards more complex defects. Exposure for precise repair is good, additional incisions can be avoided, and cosmetic results have been excellent.

Borderline hypoplastic left heart malformations: Norwood palliation or two-ventricle repair?

BACKGROUND: Patients with hypoplastic left heart syndrome (HLHS) and associated malformations undergo Norwood palliation or potentially a two-ventricle repair. METHODS: Since 8/99, 8 patients with typical HLHS and two with DILV underwent Norwood/Fontan palliation (group I). Three other patients (group II) had two-ventricle repair. Anatomy was: aortic atresia, coarctation, unrestrictive VSD (patient 1), hypoplastic mitral and aortic valve, arch and LV, coarctation (patients 2 and 3). Surgical procedures were Norwood arch reconstruction with either Rastelli operation (patient 1) or ASD-closure (patients 2 and 3). RESULTS: Operative mortality in group I was 1/8 (day 22; RV-failure). Two patients died before Glenn (sepsis, RV-failure). Six patients underwent Glenn procedure successfully. No patient died in group II. Echocardiography after 13 +/- 7.4 months showed mild homograft dysfunction (patient 1) and an LVOT-gradient of 20 mmHg (patient 3). Clinical condition of all survivors in both groups is good. CONCLUSION: Some anatomical subsets of HLHS with borderline mitral valves and small left ventricles may undergo two-ventricle repair despite severe LVOTO. Mortality and morbidity seem to be lower, but selection criteria are so far not defined.

Tissue engineering: complete autologous valve conduit--a new moulding technique.

OBJECTIVE: The use of fibrin gel, which can be produced from patients' blood, was investigated as an autologous, biodegradable scaffold. A new moulding technique was developed to create a complete aortic root. METHODS: A new moulding technique was generated for the creation of complete valve conduit. On the basis of biomechanical valve design studies, a tricuspid "ventricular" and "aortic" stamp were developed. A silicone-coated aluminum cylinder was used to circumferentially limit the mould. The cell/gel suspension was filled into the mould and polymerization was started. RESULTS: The creation of complex structures such as complete valve conduits is possible with the moulding technique described. With a layer thickness of up to 2 mm, histological investigations showed excellent tissue development with viable fibroblasts surrounded by collagen bundles. CONCLUSION: Fibrin gel unifies many properties of an ideal scaffold: The formation of complex structures is possible, the degradation and polymerization is controllable and the formation of the extracellular matrix is excellent.