Surgical Treatment of Thoracic Aortic Aneurysms in Patients with Congenital Heart Disease.

BACKGROUND: This study we evaluate our results for surgical treatment of thoracic aortic aneurysms in patients with congenital heart disease. PATIENTS AND METHODS: Fifty patients aged between 12 and 71 years were treated for 51 thoracic aortic aneurysms. Forty-four of the patients developed aneurysms in the ascending aorta and seven developed aneurysms in the descending aorta. The underlying diseases for ascending aortic aneurysms included 16 congenital aortic stenosis, 16 bicuspid aortic valves, 4 transposition of the great arteries, 3 tetralogy of Fallot, 2 truncus arteriosus communis, and 3 other diseases. Patients with connective tissue disorders were excluded. All descending aortic aneurysms developed late after coarctation repair. The time interval between the correction and aneurysm operations was 15 years in ascending aneurysms and 28 years in descending aneurysms. RESULTS: The operative procedures for 44 ascending aortic aneurysms included 38 ascending aortic replacements, with or without aortic valve replacement (including 31 conduits), and 6 David operations. Graft replacement was undertaken for the seven descending aortic aneurysms. There were two hospital deaths. Forty-eight hospital survivors were in New York Heart Association functional class II or less at follow-up, which was conducted up to a maximum of 8 years after the procedure. All patients were free from reoperation and thromboembolic events. Aortic valve function was good in all six patients after the valve-sparing operation. CONCLUSION: Thoracic aortic aneurysms in patients with congenital heart disease is highly associated with bicuspid aortic valve and aortic coarctation. For ascending aortic aneurysms, conduit replacement is the method of choice. The David procedure provides good results in selected patients. For descending aortic aneurysms, graft replacement is the preferred procedure. The relatively late development of thoracic aortic aneurysms indicates that long-term follow-up in patients with congenital heart disease, especially in patients with bicuspid aortic valve and aortic coarctation, is essential.

A modified technique of Konno aortoventriculoplasty for redo aortic valve replacement procedures.

This article puts forward a modified technique of Konno aortoventriculoplasty for repeat procedures. After incision of the ventricular septum, this approach involves aortic valve replacement using a mechanical valved conduit, reimplantation of the coronary arteries, and graft replacement of the ascending aorta. This modification allows the removal of the diseased ascending aortic wall caused by a previous patch enlargement or poststenotic dilation.

Aortic root replacement in a patient with bicuspid pulmonary valve late after arterial switch operation.

Mild to moderate neoaortic root dilatation late after arterial switch operation (ASO) is a well-documented morbidity, but rarely needs surgical replacement. Here, we report on a 22-year-old man, who developed marked dilatation of neoaortic root and needed an aortic root replacement with mechanical conduit. His aortic valve was bicuspid. Only three cases have been reported for surgical replacement of aortic root after ASO, and two of them had bicuspid neoaortic valves. We suspect that a bicuspid neoaortic valve may be a risk factor for marked dilatation of the aortic root late after ASO.

Use of fresh decellularized allografts for pulmonary valve replacement may reduce the reoperation rate in children and young adults: early report.

BACKGROUND: Degeneration of xenografts or homografts is a major cause for reoperation in young patients after pulmonary valve replacement. We present the early results of fresh decellularized pulmonary homografts (DPH) implantation compared with glutaraldehyde-fixed bovine jugular vein (BJV) and cryopreserved homografts (CH). METHODS AND RESULTS: Thirty-eight patients with DPH in pulmonary position were consecutively evaluated during the follow-up (up to 5 years) including medical examination, echocardiography, and MRI. These patients were matched according to age and pathology and compared with BJV (n=38) and CH (n=38) recipients. In contrast to BJV and CH groups, echocardiography revealed no increase of transvalvular gradient, cusp thickening, or aneurysmatic dilatation in DPH patients. Over time, DPH valve annulus diameters converge toward normal z-values. Five-year freedom from explantation was 100% for DPH and 86 ± 8% and 88 ± 7% for BJV and CH conduits, respectively. Additionally, MRI investigations in 17 DPH patients with follow-up time >2 years were compared with MRI data of 20 BJV recipients. Both patient groups (DPH and BJV) were at comparable ages (mean, 12.7 ± 6.1 versus 13.0 ± 3.0 years) and have comparable follow-up time (3.7 ± 1.0 versus 2.7 ± 0.9 years). In DPH patients, the mean transvalvular gradient was significantly (P=0.001) lower (11 mm Hg) compared with the BJV group (23.2 mm Hg). Regurgitation fraction was 14 ± 3% and 4 ± 5% in DPH and BJV groups, respectively. In 3 DPH recipients, moderate regurgitation was documented after surgery and remained unchanged in follow-up. CONCLUSIONS: In contrast to conventional homografts and xenografts, decellularized fresh allograft valves showed improved freedom from explantation, provided low gradients in follow-up, and exhibited adaptive growth.

Risk factors for distal Contegra stenosis: results of a prospective European multicentre study.

Objectives The EUCon study was designed to identify risk factors for distal anastomotic stenosis after bovine jugular vein (Contegra) implantation in children. Methods Between March 2006 and August 2008, 104 devices were implanted in nine European centers. Preoperative, intraoperative, and follow-up data (at discharge, 6, 12, 24 months) including standardized echocardiography were prospectively registered, source data verified and collected in a central database. Main endpoint was distal stenosis (either postvalvular gradient of ≥50 mm Hg or need for intervention for distal stenosis). Eight potential risk factors (age <2 years, diagnosis, running suture, use of glue, flapless anastomosis, oversizing less than + 2 z, anticoagulation, implantation site) were investigated. Cox regression, decision tree analyses, and "Clustering by Response" were applied. Results Patient age ranged from 0 to18 years, mean 6.0 ± 6.1, median 3.2 years. Implantation reasons: 88% congenital malformations, 12% Ross operations. Follow-up was 88.3% complete. Durability (freedom from death, reoperation, degeneration, endocarditis, and explantation) compared well to corresponding homograft literature. Sixteen patients reached study endpoints. Age <2 years was the only invariably significant risk factor (p = 0.044); "Clustering By Response" found young anticoagulated patients with oversized conduits to be at a higher risk than the others (p = 0.018, OR = 3.2). Conclusion Patient age is the main risk factor for development of distal anastomosis stenosis after Contegra implantation. The influence of the other investigated factors is too small to be proven in 104 patients after 2 years, or other risk factors must be taken into consideration to explain outcome differences among recipients under 2 years.

Improved results after repair of complete atrioventricular septal defect.

BACKGROUND: This study evaluates the historical impact on the outcomes of early primary repair of complete atrioventricular septal defect (AVSD) at our institute. METHODS: Since 1976, a total of 185 children with complete AVSD have been referred to our unit. Prior to 1990, 78 children received conservative therapy, and selected 51 patients underwent surgical repair (group 1). After 1990, all referred children underwent surgical repair (n = 56; group 2). Pre- and postoperative parameters were analyzed and compared among the groups. RESULTS: Age at operation was 15.4 +/- 20.4 versus 9.9 +/- 18.0 months in group 1 and group 2, respectively. Association with Down syndrome (53% vs. 82%; p < 0.01) and with patent ductus arteriosus (16 vs. 34%; p < 0.05) was less frequent in group 1. No difference was seen regarding preoperative pulmonary vascular resistance index (RPI). Actuarial survival at 15 years has improved in group 2 (69.3 +/- 6.7 vs. 90.8 +/- 3.9%; p < 0.05). Freedom from reoperation of the left atrioventricular valve at 15 years was not significantly different (78.8 +/- 6.8 vs. 90.6 +/- 4.7%; p = 0.23). Risk factor analysis identified an RPI >6.0 WU/m(2) as a risk for early death. CONCLUSION: By operating on the patients with complete AVSD earlier and not excluding patients with Down syndrome, recent results had definitely improved over the last decades. Despite this positive result, a high RPI exceeding 6 WU/m(2) still remains a risk factor for early mortality independent of early primary repair.

Aneurysm of the aortic root in the setting of Wiskott-Aldrich syndrome.

Wiskott-Aldrich syndrome is a rare X-linked disease, associated with immunodeficiency, infections, thrombocytopaenia, and eczema. Aortitis and formation of aneurysms have also been described. We describe here our experience with a 7-year-boy with this syndrome. He survived replacement of the aortic root because of an aneurysmal ascending aorta, and subsequent bone marrow transplantation.

Whole blood coagulation measured by modified thrombelastography (ROTEM) is impaired in infants with congenital heart diseases.

Patients with congenital heart disease (CHD) often do have a variety of coagulation abnormalities that results in bleeding diathesis. Our study aimed to determine the impact of cyanosis and CHD on modified thrombelastography parameters, compared with children without CHD. Preoperative blood samples were taken for TEM analyses from a total of 51 infants scheduled for surgery. The following groups were examined: normal patients without CHD, acyanotic patients with acyanotic CHD, and cyanotic patients with CHD and with preoperative hemoglobin values higher than 15 g dl(-1). Mean values of all patient groups as well as all individual values of normal patients were within their normal ranges. Within these limits, however, clots were significantly inferior in cyanotic patients (worse mean values of eight out of 10 measured TEM parameters representing the intrinsic, extrinsic, and plasmatic pathways of coagulation) and in acyanotic patients (two out of 10 TEM parameters). Individually, pathological TEM parameters were found in seven (41%) cyanotic patients (P=0.003; vs. normal patients) and in three (17%) acyanotic patients (P=0.01). More than one abnormal TEM coagulation parameter was found in four patients, all of them cyanotic patients. Hyperfibrinolysis was detected in one patient, a cyanotic patient. The present investigation confirms previous findings that in patients with CHD the heart defect itself compromises coagulation monitored with TEM, but in addition, we demonstrate that cyanosis and/or polycythemia exert the essential negative impact on hemostasis. Preoperative hyperfibrinolysis detected with TEM seems to play no important role.

Clinical application of tissue engineered human heart valves using autologous progenitor cells.

BACKGROUND: Tissue engineering (TE) of heart valves reseeded with autologous cells has been successfully performed in vitro. Here, we report our first clinical implantation of pulmonary heart valves (PV) engineered with autologous endothelial progenitor cells (EPCs) and the results of 3.5 years of follow-up. METHODS AND RESULTS: Human PV allografts were decellularized (Trypsin/EDTA) and resulting scaffolds reseeded with peripheral mononuclear cells isolated from human blood. Positive stain for von Willebrand factor, CD31, and Flk-1 was observed in monolayers of cells cultivated and differentiated on the luminal surface of the scaffolds in a dynamic bioreactor system for up to 21 days, indicating endothelial nature. PV reseeded with autologous cells were implanted into 2 pediatric patients (age 13 and 11) with congenital PV failure. Postoperatively, a mild pulmonary regurgitation was documented in both children. Based on regular echocardiographic investigations, hemodynamic parameters and cardiac morphology changed in 3.5 years as follows: increase of the PV annulus diameter (18 to 22.5 mm and 22 to 26 mm, respectively), decrease of valve regurgitation (trivial/mild and trivial, respectively), decrease (16 to 9 mm Hg) or a increase (8 to 9.5 mm Hg) of mean transvalvular gradient, remained 26 mm or decreased (32 to 28 mm) right-ventricular end-diastolic diameter. The body surface area increased (1.07 to 1.42 m2 and 1.07 to 1.46 m2, respectively). No signs of valve degeneration were observed in both patients. CONCLUSIONS: TE of human heart valves using autologous EPC is a feasible and safe method for pulmonary valve replacement. TE valves have the potential to remodel and grow accordingly to the somatic growth of the child.

Evaluation of 188 consecutive homografts implanted in pulmonary position after 20 years.

OBJECTIVE: Homografts are considered the gold standard for right ventricular outflow tract reconstruction. Their long-term durability is limited, and alternatives became available. We evaluate their long-term hemodynamic performance to permit comparisons with alternative devices. METHODS: Between 1985 and 2004, 188 homografts were implanted in pulmonary position at our institution. Mean patient age was 24.8 years (range 2 days-75 years); 56 were female and 132 male. Total follow-up time was 1073 years. Fifty-eight percent were Ross procedures (mean age 31.5 years) and 42% were different procedures (mean age 15.6 years); main diagnoses were tetralogy of Fallot (48%), truncus arteriosus (14%), transposition of the great arteries (11%). Twenty-six percent were redo implantations. We evaluated freedom from death, explantation, insufficiency, relevant gradient, degeneration, and the interval between diagnosis of degeneration and therapeutic procedure (therapeutic gap). Results were stratified by indication, age, history, homograft size, and origin. RESULTS: Ten-year-freedom-from explantation was 82% in homografts >19 mm and 45% in smaller ones. Ten-year freedom from degeneration was 68% after Ross procedure and 25% after other operations; it was 83% in patients older than 10 years at implantation and 51% in younger ones. 'Non-Ross-procedure' and 'implantation age below 10 years' were the only independent risk factors for degeneration. The observed trend towards therapeutical gap reduction was not statistically significant. CONCLUSIONS: Homograft implantation in the pulmonary position can be performed with good long-term freedom from explantation. However, freedom from degeneration is a matter of concern. Therefore, alternative valved conduits are required especially for pediatric patients.

Clinical outcome of patients 20 years after Fontan operation--effect of fenestration on late morbidity.

OBJECTIVE: The Fontan operation has been proposed as definitive palliation for an increasing variety of hearts with complex univentricular anatomy, but late morbidity after Fontan operation is still a matter of concern. This retrospective study evaluates the late outcome in patients with Fontan circulation. METHODS: We included 121 consecutive patients that underwent Fontan operation between 1984 and 2004. Modifications of the Fontan operation included atriopulmonary anastomosis (APA; n = 28), total cavopulmonary connection (TCPC; n = 63), and fenestrated TCPC (f-TCPC; n = 30). Mean age was 5.8+/-5.5 years. Post operative mortality, morbidity, hemodynamics, and somatic development were analyzed. RESULTS: Actuarial survival was 87% at 20 years after Fontan operation. There were 10 early deaths, 5 late deaths, and 2 takedowns followed by successful conversion and heart transplantation. Among 108 early-survivors with Fontan circulation, 19 underwent reoperation, including 3 conversions of APA to TCPC. Freedom from reoperation was 76% at 20 years. Freedom from intervention was 34% at 20 years. Freedom from tachyarrhythmia or pacemaker implantation was 23% and 77%, respectively at 20 years. Heterotaxy and atrioventricular valve anomaly were risk factors for late failure and tachyarrhythmias. Patients with fenestrated TCPC had reduced incidence of late tachyarrhythmias, and patients with APA who developed collaterals showed low incidence of late tachyarrythmia. Postoperative sinus node dysfunction or tachyarrhythmias was associated with significantly lower cardiac index. Somatic development was gradually compensated after Fontan operation. Weight normalized completely 15 years postoperatively. CONCLUSIONS: Long-term survival after Fontan procedure is encouraging, but late morbidity remains suboptimal. During follow-up, emerging complications should be managed by surgical and interventional procedures. Fenestration in Fontan circulation provided better cardiac output and lower incidence of late tachyarrhythmias, suggesting a benefit of fenestration for late outcome.

Decellularized aortic homografts for aortic valve and aorta ascendens replacement.

OBJECTIVES: The choice of valve prosthesis for aortic valve replacement (AVR) in young patients is challenging. Decellularized pulmonary homografts (DPHs) have shown excellent results in pulmonary position. Here, we report our early clinical results using decellularized aortic valve homografts (DAHs) for AVR in children and mainly young adults. METHODS: This prospective observational study included all 69 patients (44 males) operated from February 2008 to September 2015, with a mean age of 19.7 ± 14.6 years (range 0.2-65.3 years). In 18 patients, a long DAH was used for simultaneous replacement of a dilated ascending aorta as an extended aortic root replacement (EARR). Four patients received simultaneous pulmonary valve replacement with DPH. RESULTS: Thirty-nine patients (57%) had a total of 62 previous operations. The mean aortic cross-clamp time in isolated cases was 129 ± 41 min. There was 1 conduit-unrelated death. The mean DAH diameter was 22.4 ± 3.7 mm (range, 10-29 mm), the average peak gradient was 14 ± 15 mmHg and the mean aortic regurgitation grade (0.5 = trace, 1 = mild) was 0.6 ± 0.5. The mean effective orifice area (EOA) of 25 mm diameter DAH was 3.07 ± 0.7 cm(2). DAH annulus z-values were 1.1 ± 1.1 at implantation and 0.7 ± 1.3 at the last follow-up. The last mean left ventricle ejection fraction and left ventricle end diastolic volume index was 63 ± 7% and 78 ± 16 ml/m(2) body surface area, respectively. To date, no dilatation has been observed at any level of the graft during follow-up; however, the observational time is short (140.4 years in total, mean 2.0 ± 1.8 years, maximum 7.6 years). One small DAH (10 mm at implantation) had to be explanted due to subvalvular stenosis and developing regurgitation after 4.5 years and was replaced with a 17 mm DAH without complication. No calcification of the explanted graft was noticed intraoperatively and after histological analysis, which revealed extensive recellularization without inflammation. CONCLUSIONS: DAHs withstand systemic circulation, provide outstanding EOA and appear as an alternative to conventional grafts for AVR in young patients. EARR using DAH is a further option in aortic valve disease associated with aorta ascendens dilatation as it avoids the use of any prosthetic material.

Mid term course after pediatric right ventricular outflow tract reconstruction: a comparison of homografts, porcine xenografts and Contegras.

OBJECTIVE: Homografts and porcine xenografts are valved conduits for pediatric RVOT reconstruction. They lack availability and durability. The Contegra, a glutaraldehyde fixed bovine jugular vein, was developed as an alternative. In this article, we compare single center results of 190 RVOT conduit implantations. METHODS: 52 homografts, 30 porcine xenografts, 108 Contegras were implanted since 1992. Since 1999, data collection was prospective, for Contegras within a controlled clinical trial. Follow-up is complete for all evaluated items. We stratified reoperations by problem zone (sub-, intra-, and supravalvular) and analyzed the role of patient age, diagnosis, graft type, graft size, previous operations and year of operation on freedom from explantation or reoperation related to supravalvular reasons. RESULTS: Porcine xenografts were inferior concerning freedom from explantation and reoperation (P<0.0001). They gave erlier reason for explantation in each zone (P<0.001). At 4 years, homograft valve related reoperation need reached 20%, Contegras 0% (P=0.002). Supravalvlar reoperation reasons developed about equally in homografts and Contegras. Multivariable Cox' regression analysis showed porcine xenografts and age <1 year as independent risk factors for explantation due to supravalvular reasons. We found no reason to assume that supravalvular reoperation reasons occured more frequently after Contegra than after homograft implantation. CONCLUSION: After 12 years RVOT reconstruction with 190 valved conduits, Contegras remain our device of choice. At 4 years, they show no subvalvular or valvular reason for explantation or reoperation. Contegras have the advantages of easy handling and availability, and they compare well with homografts regarding freedom from explantation and freedom from reoperation.

Bovine valved venous xenografts for RVOT reconstruction: results after 71 implantations.

BACKGROUND: Pediatric right ventricular outflow tract (RVOT) reconstruction with homo- or porcine xenografts is problematic because of limited availability, lack of material for reconstruction, early degeneration, and tissue ingrowth. Contegra, a bovine jugular vein graft, might be an interesting alternative to overcome these problems. PATIENTS AND METHODS: Within a Federal Drug Administration controlled study, we implanted 71 Contegra pulmonary valved conduits from May 1999 to September 2001 in 71 patients (male/female 33/38) in the age range 2 days-17.4 years, median 1.2 years. Twenty five were primary repairs, 22 had previous graft implantations, and 24 had other repairs/palliations. Preoperative diagnoses: truncus arteriosus communis (19 patients), tetralogy of Fallot (32), double outlet right ventricle (13), transposition of the great arteries (5), and two rare complex malformations. The size of implanted Contegra conduits ranged from 12 to 22 mm. Echocardiography was performed at 1 and 3 months, and then every 3 months postoperatively. Follow-up time was 27 months (maximal), 80 years in total. Results were compared with our 52 homograft- and 30 Tissuemed porcine xenograft recipients. RESULTS: Contegra enables the surgeon to perform all anastomoses without additional material. Its tissue is very apt for suturing and its insufficiencies are common, but without clinical significance or tendency to increase. We saw no sign of conduit or valve degeneration during the whole follow-up up to 27 months. There were no device related adverse events. Redos: five for peripheral pulmonary arteries, two residual ventricular septum defect (VSD) closures. There were six deaths (five early, one late). The maximal transvalvular gradients of 25-42 mmHg were measured in seven patients; these gradients did not increase further during the follow-up. Six patients with completely intact Contegra conduits developed pressure gradients of more than 70 mmHg immediately distal from the conduit. At 27 months, Contegra grafts were advantageous compared to homografts with respect to survival and freedom from explantation. Right ventricle to left ventricle (RV/LV) ratio development and freedom from explantation/redo were equal for Contegra conduits and homografts. Porcine Tissuemed xenografts were significantly inferior. CONCLUSION: The Contegra conduit offers unique tailoring and suturing options for primary and redo RVOT reconstruction. At 27 months, its durability seems at least equivalent to homografts and is superior to porcine Tissuemed xenografts.

Does the noise of mechanical heart valve prostheses affect quality of life as measured by the SF-36 questionnaire?

OBJECTIVE: The closure clicks of mechanical heart valve prostheses' leaflets are quite often clearly audible. The study describes the effects of subjective valve sound perception on the patients' quality of life and analyses factors that might contribute to valve noise-related discomfort. METHODS: We included 556 patients who received a mechanical valve prosthesis and participated in the study in our institution from 1994 to 1998. All compiled the standardised questionnaire Short-Form-36 Health Survey (SF-36) and indicated their subjective disturbance grade pre- and postoperatively, then every 6 months up to 2 years. A series of factors was scanned for correlation with unpleasant noise perception. RESULTS: Two years after the operation, only 5.8% classified their valve sounds as 'quite' or 'very much' disturbing. Age <60 years and being female were statistically significant factors for persisting unease caused by valve sounds. Without one of these factors, severe disturbance chance was 1.5%. As expected, quality of life improved after surgery. Patients disturbed seriously by valve noise showed significantly lower mean life quality values on each SF-36 scale. CONCLUSION: Patients (94.2%) with mechanical heart valve replacement have no persistent complaints about the valve noise. The grade of annoyance by valve noise is paralleled by lower average quality of life. Age under 60 years or being female increases the probability of severe disturbance due to mechanical valve sounds. It remains unclear whether the disturbing noise is reason or consequence of lower quality of life.

Semilunar valve replacement with decellularized homograft after Damus-Kaye-Stansel anastomosis and fontan procedure.

We describe a patient in whom severe neoaortic (anatomic pulmonary) valve regurgitation developed late after Damus-Kaye-Stansel anastomosis and Fontan operation. The valve was replaced with a fresh decellularized homograft, which we developed and applied in the normal pulmonary and aortic position in more than 100 patients. During follow-up of more than 2 years, the valve function is excellent, and no infectious or thromboembolic complications were seen. The decellularized homograft seems to be an ideal material in this situation.

Use of latissimus dorsi pedicled myocutaneous flap for reconstruction in the chest area of an 8-month-old female infant with ectopia cordis.

Ectopia cordis (EC) is characterized by a complete or partial malposition of the heart outside the thorax. Despite the interdisciplinary treatment, the repair of EC is still very difficult and offers new surgical challenges because of its complexity and various combinations with other anomalies. We report the successful outcome after using a pedicled latissimus dorsi flap in reconstructive surgery in the setting of chronic wound dehiscence in an 8-month-old female infant born with a thoracic EC and omphalocele.

Early systemic cellular immune response in children and young adults receiving decellularized fresh allografts for pulmonary valve replacement.

OBJECTIVES: The longevity of homografts is determined by the activation of the recipients' immune system resulting from allogenic antigen exposition. Fresh decellularized pulmonary homografts (DPH) have shown promising early results in pulmonary valve replacement in children and young adults and could potentially avoid significant activation of the immune system, as more than 99% of the donor DNA is removed during the decellularization process. While the humoral immune response to decellularized allografts has been studied, detailed information on the more significant cellular immune response is currently lacking. METHODS AND RESULTS: Peripheral blood samples were obtained from patients undergoing pulmonary valve replacement with DPH before, after, and for approximately 3 years after implantation. Absolute counts and percentages of mature T- (CD3(+)), B- (CD19(+)), and natural killer- (CD16(+)/CD56(+)) cells, as well as T helper- (CD4(+)) and cytotoxic T-cell- (CD8(+)) subsets, were determined by fluorescence-activated cell sorting (FACS). Between May 2009 and September 2013, 199 blood samples taken from 47 patients with a mean age at DPH implantation of 16.6±10.8 years were analyzed. The hemodynamic performance of DPH was excellent in all but one patient, and no valve-related deaths or conduit explantations were observed. The short-term follow up revealed a significant postoperative decrease in cell counts of most subtypes with reconstitution after 3 months. Continued assessment did not show any significant deviations in cell counts from their baseline values. CONCLUSION: The absence of cellular immune response in patients receiving DPH supports the concept that decellularization can provide a basis for autologous regeneration.