Microscopic and energy dipersive x-ray analysis of surface adaptation of dental cements to dental ceramic surfaces

The authors present a retrospective study on 30 patients with prosthetic graft infection. Included are 25 patients with aortic graft infection, three with infection of a femorodistal bypass and two with infected axillofemoral grafts. There were 23 isolated primary prosthetic graft infections and seven aorto-enteric fistulas. Treatment consisted of graft excision and replacement with cryopreserved arterial homografts, harvested from brain-death multi-organ donors. The in situ technique was used in 27 cases. Eight patients died postoperatively and two deaths were from allograft related complications. The operative mortality rate was 11% for isolated aortic graft sepsis and the early limb salvage rate was 100%. Persistent or recurrent infection was noted in two cases. The mean follow-up of the series was 24.5 months and occlusive complications occurred in five patients (23%), which resulted in two major amputations. Serial CT scans showed abnormalities in six of the 22 survivors, all of them related to the aortic segment of the allograft. It is concluded that in situ reconstruction with cryopreserved arterial allografts represents an acceptable alternative, especially in the treatment of isolated aortic graft sepsis. Continued follow-up towards late deterioration and/or occlusive complications remains mandatory.     

Urinary bladder marsupialization for treatment of obstructive urolithiasis in male goats

In this study, 18 patients (17 men and 1 woman; mean age 61 years) with a previously infected vascular graft underwent vascular reconstruction with cryopreserved arterial allografts. Treatment consisted of first total (n = 11) or partial removal (n = 7) of infected prosthetic grafts. Revascularizations were aortoaortic (n = 2), aortobifemoral (n = 8), aortounifemoral (n = 3), femorofemoral (n = 2), iliofemoral (n = 1), or femoropopliteal (n = 2) bypasses. Four patients died postoperatively (22%)-one of septic necrosis of the allograft, one of septic rupture of the aortic anastomosis of a previous bypass, one of multiorgan failure, and one of mesenteric infarction. One allograft occluded within 30 days (5.5%), leading to an above-knee amputation. In the remaining patients, routine arteriography or duplex scan showed patent allografts. For the 14 survivors, the mean follow-up period was 20 months (range: 1-45 months). Two patients died-one of septicemia not related to the allograft, and one of multiple organ failure. Among the 12 survivors, 3 patients with non-ABO-compatible allografts developed different types of long-term alterations. One patient had a hemorrhage due to femoral allograft rupture at 45 days, and two patients had aortic allografts dilatation with mural thrombus, necessitating a prosthetic replacement in one patient. Cryopreserved allografts used for the treatment of infected vascular graft are useful in selected cases, although they are not totally resistant to infection. Patients should be followed closely to detect significant long-term alterations of the allografts.     

Aortic valve replacement with cryopreserved aortic allograft: ten-year experience

OBJECTIVE: Cryopreserved aortic allograft can be used for aortic valve replacement in congenital, rheumatic, degenerative, and infected native valve conditions, as well as failed prosthetic valves. This study was conducted to determine the long-term results of aortic valve replacement with cryopreserved aortic allografts. METHODS: Aortic valve replacement with cryopreserved aortic allografts was performed in 117 patients from July 1985 until August 1996. All patients requiring aortic valve replacement regardless of valve disease were considered for allograft replacement; the valve was preferentially used in patients under age 55 years and in the setting of bacterial endocarditis. Four operative techniques involving cryopreserved aortic allografts were used: freehand aortic valve replacement with 120-degree rotation, freehand aortic valve replacement with intact noncoronary sinus, aortic root enlargement with intact noncoronary sinus, and total aortic root replacement. Valve function was assessed by echocardiography during the operation in 78 patients (66%) and after the operation in 77 patients (65%). RESULTS: One-hundred eighteen aortic valve replacements with cryopreserved aortic allografts were performed on 117 patients; mean age was 45.6 years (range 15 to 83 years) and mean follow-up was 4.6 years (range up to 11 years). Intraoperative echocardiography disclosed no significant aortic valve incompetence. There were four operative deaths (3%) and seven late deaths; freedom from valve-related mortality at 10 years was 9:3% +/- 4.55%. New York Heart Association functional status at latest follow-up was normal in 98 (94%) patients. On postoperative echocardiography, 90% had no or trivial aortic valve incompetence. Freedom from thromboembolism at 10 years was 100% and from endocarditis, 98% +/- 2.47%. Seven (6%) patients required valve explantation, four for structural deterioration. At 10 years, freedom from reoperation for allograft-related causes was 92% +/- 3.47%. CONCLUSIONS: Aortic valve replacement with cryopreserved aortic allografts can be performed with low perioperative and long-term mortality. Most patients have excellent functional status, and reoperation for valve-related causes is unusual. Aortic valve replacement with cryopreserved aortic allografts demonstrates excellent freedom from thromboembolism, endocarditis, and progressive valve incompetence.     

Cryopreserved arterial allografts in the treatment of major vascular infection: a comparison with conventional surgical techniques

OBJECTIVE: Recent findings with cryopreserved heart valve allografts in the treatment of infectious endocarditis suggest that the use of cryopreserved arterial allografts may improve the outcome in patients with vascular infections. METHODS: Seventy-two patients with mycotic aneurysms (n = 29) or infected vascular prostheses (n = 43) of the thoracic (n = 26) or abdominal aorta (n = 46) were treated with in situ repair and extra-anatomic reconstruction using prosthetic material (n = 38) or implantation of a cryopreserved arterial allograft (n = 34). Disease-related survival and survival free of reoperation were assessed. Morbidity, cumulative lengths of intensive care, hospitalization, antibiotic treatment, and costs were calculated per year of follow-up. RESULTS: The use of cryopreserved arterial allografts was superior to conventional surgery in terms of disease-related survival (P =.008), disease-related survival free of reoperation (P =.0001), duration of intensive care per year of follow-up (median 1 vs 11 days; range 1 to 42 vs 2 to 120 days; P =.001), hospitalization (14 vs 30 days; range 7 to 150 vs 15 to 240 days; P =.002), duration of postoperative antibiotic therapy (21 vs 40 days; range 21 to 90 vs 60 to 365 days; P =.002), incidence of complications (24% vs 63%; P =.005), and elimination of infection (91% vs 53%; P =.001). In addition, costs were 40% lower in the group treated by allografts (P =.005). CONCLUSIONS: The use of cryopreserved arterial allografts is a more effective treatment for mycotic aneurysms and infected vascular prostheses than conventional surgical techniques.     

Primary immunosuppression with mycophenolate mofetil and antithymocyte globulin for kidney transplant recipients of a suboptimal graft

BACKGROUND: In renal transplantation the beneficial immunosuppressive effects of cyclosporin (CsA) may be curtailed by its nephrotoxicity, specially in patients receiving a cadaveric allograft from suboptimal donors or at risk of delayed graft function. Mycophenolate mofetil (MMF) and antithymocyte globulin (ATG) have each demonstrated to be potent immunosuppressants in renal transplantation. In a prospective analysis we have studied the results at 6 months of the combination of MMF, ATG and low-dose steroids in patients with low immunological risk receiving a first cadaveric renal allograft from a suboptimal donor or at risk of delayed graft function. METHODS: Patients with preformed reactive antibodies < 500% receiving a first graft from a suboptimal donor (age > or = 40 years, non-heart-beating, acute renal failure, arterial hypertension) or at risk of delayed graft function (cold ischaemia time > or = 24 h) were eligible for this open single-arm pilot trial. From September 1996 to March 1997 we recruited 17 patients. They were treated with MMF 2 g p.o. preoperatively, and after transplantation at 3 g/day; rabbit ATG i.v. at 2 mg/kg preoperatively, and 1.5 mg/kg/day the first day after transplantation, followed by four doses of 1 mg/kg on alternate days; prednisone was given at 0.25 mg/kg/day and reduced progressively to 0.1 mg/kg/day at 3 months. Primary outcomes were incidence of biopsy-proven acute rejection, delayed graft function, opportunistic infections, graft and patient survival, and the need for introduction of CsA treatment. RESULTS: delayed graft function occurred in two cases (12%). Four of 17 patients (24%) had a biopsy-proven acute rejection (2 grade I and 2 grade II) within the first 3 months after transplantation. CsA was added in two cases with grade II biopsy-proven acute rejection, and in one with grade I biopsy-proven acute rejection. In one patient MMF was replaced by CsA because of gastrointestinal intolerance. Mean serum creatinine 6 months after transplantation was 159+/-59 micromol/1. Cytomegalovirus tissue invasive disease occurred in one patient (6%). At 6 months follow-up all patients are alive with functioning allografts. CONCLUSIONS: These preliminary results suggest that in low-immunological-risk patients who receive a suboptimal renal allograft or at risk of delayed graft function, the combination of MMF, ATG, and steroids is an efficient immunosuppressive regime that may avoid the use of CsA in 70% of the recipients.     

DNA requirements in vivo for phage T4 packaging

OBJECTIVE: We sought to determine the morphology, mechanisms of deterioration, cellular viability, extracellular matrix integrity, and the role of immune responses in the dysfunction of cryopreserved aortic and pulmonic valve allografts. METHODS: We studied 33 explanted left-sided (n = 20) or right-sided (n = 13) cryopreserved human allograft heart valves explanted several hours to 9 years after operation, 14 nonimplanted allografts, and 16 aortic valves removed from transplanted allograft hearts 2 days to 4 years after operation. Analysis included gross inspection, radiography, light microscopy, electron microscopy, and immunohistochemical studies. RESULTS: Allografts implanted for more than 1 day had progressive collagen hyalinization and loss of normal structural complexity and cellularity, including endothelium and deep connective tissue cells. Inflammatory cells were generally minimal or absent in the allografts. Transmission electron microscopy of long-term cryopreserved allograft valves revealed no viable cells, focal calcification centered around dead cell remnants, and distorted but preserved collagen. In contrast, aortic valves from transplanted hearts showed remarkable structural preservation, including endothelium and abundant deep connective tissue cells; inflammatory infiltrates were generally mild and of no apparent deleterious consequence, including valves from patients who died of fatal rejection. CONCLUSIONS: Cryopreserved allografts are morphologically nonviable; their collagen is flattened but largely preserved. They are unlikely to grow, remodel, or exhibit active metabolic functions, and their usual degeneration cannot be attributed to immunologic responses. In contrast, aortic valves of transplanted hearts maintain near-normal overall architecture and cellularity and do not show apparent immunologic injury, even in the setting of fatal myocardial parenchymal rejection or graft arteriosclerosis.     

Hemodynamic performance of cryopreserved aortic homograft valves during midterm follow-up

OBJECTIVES: The aim of this prospective study of adult patients operated with a cryopreserved aortic homograft was to use serial echocardiographic data to evaluate the postoperative hemodynamic performance of these valves. BACKGROUND: Only limited data on hemodynamic performance of aortic homografts at rest and during exercise are available. Controversy also exists regarding incidence and progression of aortic regurgitation (AR). METHODS: Fifty-nine patients aged 39-86 years who received an aortic homograft (median size 21 mm) implanted with subcoronary technique were studied with serial Doppler-echocardiography (D-E). In 31 of these patients, D-E also was performed during supine exercise. RESULTS: Overall survival was 100% during a median follow-up of 28 months (range 4-54). During follow-up AR grade II or more was detected in 25% of the patients with an increasing time-related risk of developing AR. Maximum and mean pressure differences at 7 months follow-up calculated with the short form of the Bernoulli equation were 11.4 (4.6) and 5.5 (2.1) mm Hg, respectively. During supine exercise that increased cardiac output 72%, maximum pressure difference increased from 11.9 (5.2) to 18.5 (9.5) mm Hg. CONCLUSIONS: The aortic homograft valve shows low pressure differences at rest and during exercise, but AR grade I or II is often seen during follow-up. As AR progresses with time we stress the importance of echocardiographic follow-up of patients with aortic homografts.     

Sub-trochanteric fractures. A comparative study between gamma nail and angular osteosynthesis with lateral cortical support]

METHODS: Thirty-three children and young adults with congenital aortic valve disease underwent pulmonary autograft replacement of the aortic valve between October 1993 and March 1997. There wer six females and 27 males; at operation, median age was 16 years (range: 3 to 41 years) and median body weight 60 kg (range: 14 to 121 kg). Fifteen patients (46%) had undergone one or more previous cardiac surgical procedures. A bicuspid aortic valve was present in 31 patients (94%); moderate to severe aortic stenosis and regurgitation was present in 10 (30%) and 26 (79%), respectively. RESULTS: All patients underwent the Ross procedure while in NYHA class I (64%) or class II (36%). A preoperative shortening fraction of 41 +/- 1.4% suggested well-preserved systolic function, but the mean left ventricular end-diastolic pressure of 16.6 +/- 1.3 mmHg was consistent with preoperative left ventricular pressure and volume overload. The aortic root was replaced using an interrupted suture technique in two patients and with three separate running sutures in 31. The right ventricular outflow tract was reconstructed in all classes with a cryopreserved pulmonary homograft valved conduit (median diameter 23 mm; range 19 to 30 mm). Intraoperative complications included transient atrioventricular dissociation (one), permanent atrioventricular dissociation (one), and left coronary artery distortion relieved by shortening the distal ascending aorta (one). Postoperatively, postpericardiotomy syndrome developed in six patients (18%), supraventricular tachycardia in three (9%), and ventricular tachycardia in one (3%). At three days after surgery, one patient developed ischemic left ventricular dysfunction requiring repositioning of the distorted left coronary artery higher on the neo-aortic root. Hospital survival rate was 100%. During a median follow-up of 17 months (range: 1 to 41 months) one patient suffered a non-cardiac death due to blunt trauma. there has been a significant postoperative improvement in NYHA class among surviving patients (class I, 94%; class II, 6%; p = 0.004 versus preoperative). Postoperative aortic regurgitation was absent or trivial in 17 (60%) and mild in the remaining 11 (40%) patients for whom follow-up echocardiographic data are available. One patient required reoperation 16.5 months after the Ross procedure to replace a rapidly degenerating pulmonary homograft, and one with moderately severe homograft stenosis and five with mild homograft stenosis are being monitored. Postoperatively, a gradual early expansion in the diameter of the neo-aortic root and reduction in echocardiographic indices of left ventricular hypertrophy and dilatation occurred. CONCLUSIONS: Pulmonary autograft replacement of the aortic valve in young patients with congenital aortic valve disease has produced excellent short-term anatomic/physiologic results and symptomatic relief with no mortality. Indices of left ventricular dilatation and hypertrophy regress after repair when the Ross operation precedes important deterioration in preoperative ventricular function. Important technical considerations include: (i) the native distal ascending aorta should be sufficiently shortened before performing the distal aortic anastomosis; and (ii) the left coronary anastomosis should be positioned relatively high on the neo-aortic root with a slight amount of tension. Both of these maneuvers reduce the likelihood of coronary artery distortion. Rapid degeneration of the pulmonary homograft and the propensity towards progressive dilatation of the neo-aorta are important postoperative considerations. Until more is known about the etiology and natural history of these two potential complications, postoperative anti-inflammatory and/or immunosuppressive therapy and strict control of hypertension should be strongly considered.     

Cell-free arterial grafts: morphologic characteristics of aortic isografts, allografts, and xenografts in rats

PURPOSE: Chronic rejection of arterial allografts and xenografts results in arterial wall dilation and rupture, making them unsuitable for long-term arterial replacement in vascular surgery. In the arterial wall, as in other organs, the cells probably carry major antigenic determinants. Arterial wall cellular components can be removed by detergent treatment to produce a graftable matrix tube. METHODS: We compared the patency and macroscopic and microscopic morphologic changes that occurred in sodium dodecyl sulfate (SDS)-treated and untreated arterial isografts, allografts, and xenografts 2 months after implantation in rats. We quantified elastin, collagen, and nuclear density in the three layers of the graft wall (intima, media, and adventitia) by morphometric methods. The SDS treatment removed endothelial and smooth muscle cells and cells in the adventitia but preserved elastin and collagen extracellular matrix. RESULTS: All arterial xenografts, whether SDS treated or untreated, were aneurysmal 2 months after grafting, with loss of the medial cellular and extracellular components. In allografts, SDS treatment prevented dilation, reduced adventitial inflammatory infiltration, and preserved medial elastin. The SDS-treated allografts had an evenly distributed, noninflammatory intimal thickening that was richer in elastin fibers than that in untreated allografts. CONCLUSIONS: These results suggest an interspecies, but not an intraspecies, graft antigenicity of arterial extracellular matrix. The SDS treatment prevented chronic rejection of the arterial allograft and led to the proliferation of an elastin-rich and adapted intima.     

Application of cryopreserved allograft to aortic root replacement for valve detachment case due to aortitis

A 54-year-old male who had received an aortic valve replacement with SJM 23 about 3 years before suffered from an acute cardiac failure because of the valve detachment. From his clinical course, it was diagnosed that the aortic valve insufficiency was complicated by an aortitis. We operated on him by an aortic root replacement using a cryopreserved allograft which we prepared. A donor of the allograft was 35-year-old male, died of a subarachnoidal hemorrhage. We harvested his aortic root at an autopsy and dipped it into a nutrition medium with 10% dimethylsulfoxide. Within 10 hours from his death, we froze the tissue using a program freezer and stored it in a liquid nitrogen for 7 months. After thawing it in 37 degrees C water quickly, we rinsed the graft and used for the operation. The cell viability of the graft was confirmed by a tissue culture. Indication of the allograft valve to an aortitis case is still controversial. We think the allograft is recommendable to valve detachment case due to aortitis, because the softness of the graft decreases a compliance mismatch between the graft and the patient's annulus, which may prevent redetachment. Although we felt concern about redetachment of the conduit due to the weakness of the patient's aortic annulus, no complication regarding the allograft happened at all as yet.     

Experimental study of tracheal allotransplantation with cryopreserved grafts

OBJECTIVE: Tracheal reconstruction is necessary in patients with extensive tracheal stenosis caused by neoplasm, trauma, and congenital disease. We investigated the possibility of tracheal allotransplantation with cryopreserved grafts in a canine model. METHODS: A seven-ring section of thoracic trachea was removed in 19 adult mongrel dogs. In group A (n = 4), a five-ring tracheal autograft was implanted. In group B (n = 6), a five-ring allograft was implanted without immunosuppression. In group C (n = 9), a five-ring cryopreserved tracheal allograft was implanted without immunosuppression. Omentopexy wrapping around the grafts and both anastomotic sites was used in all animals. RESULTS: All grafts survived without any evidence of atrophy or stenosis in group A. All animals in group B died of severe airway obstruction within 1 month, and postmortem examination of these grafts showed epithelial defect and necrotic tracheal cartilage in the scar tissue. In group C, no animals died of asphyxia caused by severe stenosis of the grafts. The graft epithelium was no longer present 20 days after transplantation, and the graft was covered with regenerated epithelium within about 60 days after the operation. CONCLUSION: These findings show that cryopreserved tracheal allografts can be transplanted by means of omentopexy without immunosuppression and that cryopreservation may reduce tracheal allogenicity.     

Intimal thickening develops without humoral immunity in a mouse aortic allograft model of chronic vascular rejection

BACKGROUND: The major threat to the long-term survival of cardiac allograft recipients is the development of diffuse intimal thickening in the allograft coronary arteries through mechanisms that are poorly understood. Although antidonor antibodies have been associated with the development of this condition, a causal relationship has not been established. METHODS AND RESULTS: To determine whether humoral immune responses are necessary for the development of graft vascular disease, we performed abdominal aortic allografts from normal donor mice into different immunodeficient recipient mice: those lacking all donor-specific immune responses (severe combined immunodeficient [SCID] mice and recombination activating gene-1 [RAG-1]-deficient mice) and those lacking humoral immune responses alone owing to a targeted deletion of the joining region (JH) gene segments for the immunoglobulin heavy chain. At 6 to 9 weeks after transplantation, aortic allografts in normal immunocompetent recipients showed concentric intimal thickening extending the full length of the graft (percent luminal reduction, [%LR], 31.2 +/- 9.1 [mean +/- SD] and 38.5 +/- 3.6 in different donor-recipient strain combinations). In contrast, syngeneic (histocompatible) aortic grafts showed a normal-appearing vessel wall (%LR, 1.6 +/- 0.7). In both SCID and RAG-1-deficient recipients, aortic allografts showed a virtual absence of neointimal formation (%LR, 3.7 +/- 2.1 and 3.8 +/- 1.6 in SCID and RAG-1-deficient recipients, respectively), indicating a critical etiological role for alloimmune responses in this model. Importantly, allografts in JH-deficient mice showed marked intimal thickening (%LR, 35.7 +/- 7.9), with an appearance histologically indistinguishable from that of normal immunocompetent recipients. CONCLUSIONS: Neointimal formation in graft vascular disease is critically dependent on alloimmune responses of the host. Humoral effector mechanisms, however, may not be required.     

Increased pulmonary flow velocities in oversized homografts in patients after the Ross procedure

OBJECTIVE: Between September 1991 and July 1996, 60 patients (mean age 29.8 +/- 9 years; range 5-57) underwent aortic root replacement with pulmonary autograft, a viable biologic and nondegenerating substitute. The pulmonary root was replaced with cryopreserved homografts from cardiac transplant recipients. The aim of this study was to evaluate differences in early valve function of viable and cryopreserved allografts. METHODS: All patients had Doppler echocardiographic examinations preoperatively, at discharge from hospital and 54 patients at 1 year follow-up. We measured aortic and pulmonary peak flow velocities with continuous and pulsed-wave Doppler, and graded aortic and pulmonary insufficiency (AI, PI) with color Doppler flow (grade 0-IV). Intraoperatively, the diameters of the pulmonary root and the pulmonary homograft were measured with standard valve probes and matched to body surface area. RESULTS: Pulmonary peak flow velocity (PVmax) increased significantly from preoperative 0.87 +/- 0.11 m/s to 1.30 +/- 0.34 m/s postoperatively (P < 0.001). The implanted homografts (mean 25.9 +/- 2.4 mm) were larger than their native pulmonary diameter (mean 23.3 +/- 1.8 mm) in all patients. Homograft size matched for body surface area (BSA) did not correlate with increased PVmax. There was a significant increase of PVmax at follow-up (FU) since discharge, also (1.83 +/- 0.53 m/s; P < 0.001). Pulsed-wave Doppler demonstrates that increase of PVmax is located directly at the homograft leaflets and not at the anastomoses. Aortic peak flow velocities (AVmax) were normal postoperatively and at FU (post = 1.35 +/- 0.35 m/s; FU = 1.17 +/- 0.27 m/s). There was no significant change in AI or PI since discharge (AI FU = 0.8 +/- 0.4; PI FU = 0.7 +/- 0.5). Eight patients with fever and symptoms diagnosed as post-pericardiotomy syndrome had significantly higher PVmax at FU (PVmax = 2.41 +/- 0.40 m/s; P < 0.02). CONCLUSIONS: The Ross procedure leads to normal AVmax but significant increase of PVmax even in oversized cryopreserved homografts immediately after surgery. Further increase of PVmax without changes in AVmax in the first year demonstrates that changes in flow velocities are valve related and not due to increase in cardiac output. Further investigations will be necessary to determine whether this observation is due to valve rejection or early leaflet degeneration and treatment with immunosuppressive therapy is warranted.     

Factors related to the donor organ are major determinants of renal allograft function and survival

In this study, we analyzed the relative impact of donor and recipient variables on cadaveric renal allograft function and survival. The unique feature of the study population is that each pair of recipients received their allografts from a single donor. The study includes 378 adult patients. In 129 pairs both recipients were Caucasian, and in 60 pairs one recipient was Caucasian and the other was African-American. All transplants were done in one center, thus minimizing differences in preservation time and providing uniform posttransplant management. The initial analysis showed a relationship between the function of the allograft 6 months after transplantation (serum creatinine [SCr]6 mo) and donor variables (P = 0.0004, analysis of variance). Furthermore, it was calculated that 64% of the variability in the SCr 6mo among patients was due to donor factors and 36% was due to recipient factors. An elevated SCr 6 mo was significantly associated with older donors, male recipients, and patients with acute rejection episodes. Furthermore, other unidentified donor factors may have an impact on allograft function. Reflecting the importance of donor factors, there was a significant relationship between SCr 6mo in paired recipients (P < 0.0008 by Spearman). Analysis of racially dissimilar pairs showed that the SCr 6mo and graft survival 6 months after transplantation were not significantly different between Caucasians and African-Americans. However, beyond 6 months, graft survival was worse in African-Americans (P < 0.0001 by Cox). Compared with Caucasians, graft survival was significantly worse in African-Americans with poorly controlled blood pressure (mean arterial pressure > 105 mmHg) (P = 0.002, Cox), but not in those patients with mean arterial pressure < 105 mmHg. In conclusion, donor factors are major determinants of renal allograft function. However, those factors may not be easily identifiable or quantifiable. Donor factors do not contribute to racial differences in allograft survival. However, poorly controlled hypertension correlates with poor renal graft survival in African-Americans.     

The distinction between coronary and myocardial reperfusion after thrombolytic therapy by clinical markers of reperfusion

BACKGROUND: On the basis of a previous experience in a chronic sheep model in which partial mitral allografts remained viable and properly functioning 12 months after operation, we assessed the results obtained by replacing the tricuspid valve with fresh antibiotic-preserved mitral allografts. METHODS: Twenty 3-month-old sheep with a mean weight of 23.7 +/- 2.3 kg underwent cardiopulmonary bypass and had a fresh antibiotic-preserved mitral allograft implanted in the tricuspid position with the heart beating under normothermic conditions. The tricuspid valve apparatus was not excised. After a mean follow-up of 13.2 months, the allograft was evaluated by gross inspection and light and electron microscopy. RESULTS: Nine sheep died of technical causes within the first week after operation and 2 at 4 and 6 months of infective endocarditis of the allograft. The hemodynamic study before heart explantation revealed residual tricuspid incompetence in 3 of the 9 survivors. Macroscopic examination showed flexible valves with no signs of structural deterioration, calcification, or thrombosis. Under light and scanning electron microscopic examination, allografts were almost completely denuded of endothelial cells and showed loosely arranged connective tissue with scarce signs of inflammatory reaction. Despite these findings, allografts were free from major structural damage. CONCLUSIONS: The mitral homograft could be an alternative to replacement of the tricuspid valve with a bioprosthesis or a mechanical prosthesis.     

Endothelial activation and development of coronary artery disease in transplanted human hearts

CONTEXT: The development of coronary artery disease in heart transplants is often associated with graft failure. Early detection of allografts prone to develop this disease is essential to institute new therapeutic approaches that could prolong allograft function. OBJECTIVE: To determine if early activation of arterial/arteriolar endothelium predicts the development of coronary artery disease, graft failure, or both in transplanted human hearts. DESIGN: Prospective cohort study. SETTING: Heart Transplant Center. PARTICIPANTS: A total of 121 consecutive adult cardiac allograft recipients who received transplants between 1988 and 1995 and were followed up through 1996. MAIN OUTCOME MEASURES: Development of coronary artery disease and graft failure. METHODS: Immunocytochemistry was performed on serial endomyocardial biopsy specimens to evaluate endothelial activation markers (intercellular adhesion molecule-1 and histocompatibility antigen HLA-DR) in arteries and arterioles. The presence and progression of coronary artery disease was evaluated by annual coronary angiograms with side-by-side comparisons. RESULTS: None of the 121 donor hearts showed arterial/arteriolar endothelial activation before transplantation. Arterial/arteriolar endothelial activation was present in 78 and absent in 43 of 121 allografts during the first 3 months after transplantation. The time of appearance and the proportion of biopsy specimens showing endothelial activation during these first 3 months were significantly associated with the risk of developing coronary artery disease, the progression of the disease, and the time required to develop the disease (P<.001). Significantly more patients with arterial/arteriolar endothelial activation died or received a second transplant (P<.001). CONCLUSIONS: Activation of arterial/arteriolar endothelium in transplanted human hearts predicts development of coronary artery disease and increased risk of graft failure.     

Ablation of irreversibly rejected renal allograft by embolization with absolute ethanol: a new clinical application

Surgical allograft nephrectomy has been the conventional therapy for removing failed kidney allografts when clinical manifestations of graft intolerance appear. However, removal of a transplanted kidney is an extensive surgical procedure. On the other hand, transcatheter vascular embolization (TVE) has proven useful in ablating organs and could be applied to renal transplant ablation. The aim of this study was to present the results of TVE for the treatment of graft intolerance syndrome (GIS) in failed allograft kidneys. Transcatheter vascular embolization was performed in 14 allograft recipients (33 +/- 13 years of age; 10 men and four women) affected by GIS after irreversible kidney allograft failure. Graft intolerance syndrome was diagnosed by fever (93%), hematuria (50%), graft pain (36%), flu-like symptoms (29%), and increased graft size (29%). Absolute ethanol (0.1 mL/kg body weight) was injected in the allograft artery, and in seven patients a stainless steel coil was left in the renal artery following ethanol injection. All patients showed clinical disappearance of the GIS. No major complication occurred, although a postembolization syndrome of pain, fever, hematuria, numbness, and paresthesia of the affected area appeared in 11 of the 14 patients. After 2 to 56 months of follow-up no late complications occurred, with the exception of a graft abscess formation in one patient after 6 months of embolization. Subsequent transplantectomy was uneventful. In conclusion, TVE is a safe and effective method for kidney graft ablation, and it may become an alternative treatment for GIS following irreversible rejection.     

Bullous erythema multiforme following topical diphenylcyclopropenone application

A 68 year-old woman underwent replacement of the descending thoracic aorta with a cryopreserved aortic homograft for the treatment of a Stanford B dissecting aneurysm. After surgery, the patient made an uneventful recovery without recurrent infection. In such cases, the use of aortic homografts to replace aortic segments is a promising and effective therapeutic option.     

Aortic valve replacement with biological substitute

In the quest for an ideal aortic valve substitute, homografts and autografts are well-established options. We reviewed our results with homografts and autografts for aortic valve replacement during the last 5 years. From March 1992 through July 1997, 189 patients (138 male and 51 female), age 8 months to 68 years (mean 31.0+/-4.2 years), underwent aortic valve replacement with a human biological substitute. Of these, 93 patients received a cryopreserved or antibiotic-preserved aortic/pulmonary homograft, whereas 96 patients underwent a Ross procedure. Etiology was rheumatic in 143 (75.6%) patients, bicuspid aortic valve in 40 (21.2%), Marfan's disease in 5 (2.6%), and myxomatous aortitis in 1 (0.5%). Among the homograft group, a scalloped subcoronary implantation technique was used in 54 patients, whereas 32 patients underwent root replacement. Five patients required aortic root and ascending aortia replacement for annuloaortic ectasia. In all patients undergoing the Ross procedure, a root replacement technique was used. Operative mortality was 7.4% (14 patients). Late mortality was 5.3% (10 patients). Follow-up ranged from 1 to 46 months postoperatively. In patients with homograft aortic valve replacement, 76 patients (91.5%) had trivial to mild aortic regurgitation, while 7 patients (8.4%) had important aortic regurgitation. In patients with the Ross procedure, 78 patients (89.6%) had trivial to mild regurgitation. Moderate to severe aortic regurgitation was present in 9 patients (10.3%), all of whom had rheumatic heart disease and were young (< 30 years at surgery). We conclude that homografts and autografts provide an excellent substitute for the diseased aortic valve. Young age (< 30 years) with rheumatic etiology is a major risk factor for early progressive aortic regurgitation in patients undergoing the Ross procedure.     

Treatment of major defects of bone with bulk allografts and stemmed components during total knee arthroplasty

We reviewed the results an average of fifty months (range, twenty-four to 120 months) after the use of thirty-five allografts in thirty patients during primary or revision total knee replacement. Twenty-nine femoral-head allografts, five distal femoral allografts, and one proximal tibial allograft were used in conjunction with a long-stemmed implant to reconstruct large osseous defects. The patients were evaluated clinically, radiographically, and subjectively (with use of a questionnaire). Twenty-six (87 per cent) of the thirty patients had a good or excellent clinical result, and no revisions were necessary. As none of the patients had collapse of the graft, subsidence of the implant, or revision, we believe that the outcome of treatment with a femoral-head allograft, particularly in association with a component inserted with cement, is excellent. Four non-porous-coated components were placed without cement on structural allografts. Radiographically, three of those components subsided, but none of the three needed revision and two were associated with a good clinical result. Our current practice is to cement components in all arthroplasties involving grafting. Our findings suggest that the use of a stemmed component reduces the stress on the allograft, host bone, and fixation interface. In addition, such a component contributes to the longevity of a total knee replacement associated with a bone graft. Additional studies with long-term follow-up are necessary to confirm this outcome.