Predictive value of intraoperative biopsies and liver function tests for preservation injury in orthotopic liver transplantation

Eighty liver allografts were studied to determine the predictive value of intraoperative biopsies and postoperative liver function tests for the development of preservation injury (PI). Peak transaminase (aspartate transaminase [AST] and alanine transaminase [ALT]) and prothrombin time (PT) values achieved by each patient during postoperative days (POD) 1 through 7 were determined. PI in day 0 preperfusion biopsies (0Pre) (obtained immediately before implantation) and postperfusion biopsies (0Post) (obtained immediately after revascularization) was categorized by histological criteria as present or absent. PI in biopsies taken during POD 2 through 14 was histologically graded as either moderate-to-severe, mild, or absent. Of the 80 allografts, 8 were omitted because of primary nonfunction or postoperative complications. 0Pre and 0Post biopsies were available on 25 of 72 (35%) and 69 of 72 (96%) allografts, respectively. Only 2 (8%) of the 0Pre biopsies showed histological PI compared with 48 (70%) of the 0Post biopsies. Fifty-nine patients were biopsied between POD 2 through 14. Of these, 15, 28, and 16 patients developed moderate-to-severe, mild, or no evidence of PI, respectively. The presence of PI in the 0Post biopsy strongly correlated with the development of PI during POD 2 through 14 (P < .0005). Peak AST and ALT values in patients with moderate-to-severe PI on POD 2 through 14 were significantly elevated compared with those patients with either mild (P = .01 and .03) or no PI (P = .02 and .006). Because of extensive overlap in AST and ALT values between the three groups, however, transaminase values were not useful in predicting the presence or absence of PI in the individual case. The development of PI during POD 2 through 14 correlated with advanced donor age (P = .06) but was unassociated with 0Pre biopsy findings, cold ischemia time, or peak PT values. We conclude that the 0Post biopsy is a valuable tool for the prediction of subsequent PI in the early postoperative period. In contrast, 0Pre biopsy findings and peak AST and ALT values are not useful in the assessment of PI.

Liver transplantation for hepatitis B cirrhosis: clinical sequela of passive immunization

Aggressive administration of hepatitis B immune globulin (HBIg) has been shown to prevent hepatitis B viral (HBV) infection of the allograft; however, the clinical sequela of such therapy has not been previously described. We reviewed our experience with high dose, intravenous infusion of an intramuscular HBIg preparation to assess the effectiveness and complications of such therapy. Thirty three orthotopic liver transplants (OLTx) were performed in 32 patients with chronic HBV cirrhosis at the University of Virginia between March 1990 and June 1995. Twenty-nine of 32 (91%) patients remain free of HBV recurrence (defined by undetectable serum HBsAg and HBV-DNA) after a mean of 21 months (2-54 months), with one patient requiring retransplantation. Three (10%) patients died of non-HBV causes (two vascular events, one infectious event). Twenty episodes of acute cellular rejection were treated in 18 patients (two had two episodes). Sixteen rejections occurred within 18 d of transplant, 19 by day 120, and one late rejection occurred at 18 months owing to medication non-compliance. Eighteen patients had at least one documented infection. Six patients were treated for CMV infection (five empirically). Eight patients were treated for HSV infections (seven mild herpetic labialis and one herpetic keratitis). Four patients had documented fungal infection (one mucormycosis pneumonia and three minor superficial mucosal infections). With the exception of one necrotizing pneumonia, 11 bacterial infections were successfully treated with conventional antimicrobial agents. No patient developed post-transplant lymphoproliferative disorder. Symptoms associated with HBIg infusion were intermittent but frequent and consisted of myalgias, predominantly back pain (90%), headache (20%) and flushing (5%). No patient experienced anaphylaxis, fever, rash, arthritis or hypotension. Despite the potential for mercury toxicity and HCV transmission in the HBIg formulations currently available in the United States, serum mercury levels remained below standards for industrial exposure (60 micrograms/ml), and only one individual developed post-transplant HCV infection after receiving multiple units of unscreened blood prior to 1991.

SUMMARY

High-dose HBIg prevented HBV infection of the allograft in 29 of 32 patients transplanted for HBV cirrhosis with three non-HBV associated deaths. The intravenous infusion of HBIg was frequently associated with minor side effects that were safely tolerated by patients. The risk of HCV transmission and mercury toxicity are minimal, but support the need for a new intravenous formulation of HBIg. HBIg therapy successfully decreased post-OLTx HBV recurrence with no clinical events associated with immunosuppression. Patients did non experience allergic or infusion-related complications that altered or terminated therapy. Manufacturing modifications of HBIg may allow for improved patient tolerance and decreased risks.

Accuracy and significance of pretransplant liver volume measured by magnetic resonance imaging

Measurement of liver volume in patients with advanced liver disease is used to gauge the appropriate size of donor organs and may have prognostic value. We sought to determine the accuracy of magnetic resonance imaging (MRI) in measuring liver volume in 19 adult patients under consideration for liver transplantation. We also correlated the liver volume determination to the clinical severity of disease. Liver volume was measured at MRI by averaging the calculated volumes from coronal and transverse breath-hold T1-weighted images. These results were compared to the explanted liver volume measured by fluid displacement and the explant mass. The correlation coefficient for MRI liver volume and the explant displacement volume was 0.90. The mean liver volume for Child-Pugh class AB by MRI was 1986 +/- 568 mL (1002-2470 mL) compared to 1433 +/- 379 mL (540-1889 mL) in Child-Pugh class C patients (p = .02). We conclude that MRI offers an anatomically accurate means of determining adult liver volume in vivo. Lower mean liver volumes were observed in Child-Pugh class C patients. In addition to its ability to provide tumor screening and vascular assessment, MRI is able to provide accurate determinations of liver volume in patients undergoing liver transplant evaluations.

Prostaglandin E1 administration following orthotopic liver transplantation: a randomized prospective multicenter trial

BACKGROUND & AIMS

Prostaglandin E1 (PGE1) has been used after orthotopic liver transplantation (OLT) based on limited clinical data suggesting PGE1 infusion improves immediate hepatic allograft function. The aim of this study was to conduct a randomized double-blinded multicenter trial to evaluate the effect of PGE1 on early hepatic and renal function in patients undergoing OLT.

METHODS

One hundred eighteen patients were randomized to receive either PGE1 or crystalloid placebo intravenously after allograft revascularization. Primary end points were incidence of primary allograft nonfunction (PNF) or severe renal dysfunction.

RESULTS

The incidence of PNF was 6.7% (4 of 60) and 6.9% (4 of 58) in the control and PGE1 groups, respectively. PGE1 infusion was, however, associated with improved early renal function (mean peak creatinine level of 1.4 +/- 1.0 and 2.0 +/- 1.0 in patients treated with PGE1 and placebo, respectively; P < 0.001). Severe renal dysfunction occurred more frequently in the placebo group (26.7%) than in the PGE1 group (13.8%; P = 0.65). Additionally, dialysis treatments were more frequent in the placebo group (0.7 +/- 2.0 per patient) than in the PGE1 group (0.2 +/- 1.0 per patient; P = 0.10). Initial intensive care unit stay was shorter in patients treated with PGE1 (4.0 +/- 3.6 days) compared with controls (10.5 +/- 17.1 days) (P < 0.01).

CONCLUSIONS

PGE1 administration after OLT resulted in improved renal function and decreased initial postoperative intensive care unit stay but did not affect the incidence of PNF.

Improved outcome of orthotopic liver transplantation for chronic hepatitis B cirrhosis with aggressive passive immunization

Passive immunization with hepatitis B surface antibody (anti-HBs) is important to prevent hepatitis B virus (HBV) recurrence after orthotopic liver transplantation for chronic HBV cirrhosis. Hepatitis B immune globulin (HBIG) dosing regimens have been poorly defined, utilize numerous routes of administration, and result in a high rate of HBV relapse and mortality. Twenty-five of 27 (93%) patients transplanted (four retransplants) for chronic HBV cirrhosis show no evidence of recurrent HBV (range, 2-55 months). Anti-HBs titers necessary to minimize the risk of hepatitis B surface antigen detectability were >500 IU/L for days 0 to 7, >250 IU/L for days 8 to 90, and >100 IU/L thereafter. Pretransplant HBV E antigen (HBeAG)-positive patients required more HBIG to achieve these goals than HBeAG-negative individuals. The elimination of anti-HBs changed continually for the initial 3 posttransplant months. The anti-HBs half-life increased from 0.7 days to 14.1 days. Anti-HBs elimination was significantly different in HBeAG+ and HBeAG- patients for the first week, but was subsequently indistinguishable after week 1. After 3 months, the half-life was statistically less for HBeAG+ patients, but the difference did not influence the clinical treatment regimens. Quantitative hepatitis B DNA levels did not predict the amount of HBIG required. HBV recurrence after orthotopic liver transplantation can be reduced by aggressive passive immunization. Pharmacokinetic analysis of anti-Hbs elimination can improve immunoglobulin therapy and prevent recurrence of clinical hepatitis.

Clinical and histologic patterns of early graft failure due to recurrnet hepatitis C in four patients after liver transplantation

Hepatitis C viral recurrence after orthotopic liver transplantation is almost universal. Hepatitis C induced graft failure may occur, but the clinical and histologic profiles are not well defined. The aim of this study was to describe the pattern of early graft failure in patients with recurrent hepatitis C after liver transplantation. Thirty patients with hepatitis C underwent liver transplantation from October 1989 through September 1994. Four patients were excluded because of death (2 patients), graft failure unrelated to hepatitis C (1 patient), and lost to follow-up (1 patient). Hepatitis C recurred in 24 of the 26 remaining patients. In 4 patients with hepatitis C virus recurrence and cholestasis, graft failure developed at 5.25, 11.0, 11.0, and 18.5 months. The medical records and liver biopsies were reviewed. In all 4 patients, a histologic pattern characterized by centrilobular ballooning degeneration developed and progressed to involve more than two-thirds of the lobules. Moderate to severe cholestasis and bridging fibrosis were present in all grafts at explant. Two patients had portal inflammation on 3-month biopsies consistent with viral hepatitis. All patients had mild macrovesicular steatosis, but only 1 patient had significant lymphoid aggregates. No patient had evidence of hepatic artery thrombosis. One patient had potential drug-induced cholestasis. One patient had 3 episodes of rejection that were not believed to contribute to graft loss. All 4 patients developed clinical features of hepatic failure and were retransplanted. Two patients had early recurrence of graft failure. We conclude that a pattern of progressive centrilobular ballooning degeneration, bridging fibrosis, and cholestasis occurs in some patients with hepatitis with early graft failure, similar to fibrosing cholestatic hepatitis seen in some transplant patients with recurrent hepatitis B.

Hepatitis C virus in body fluids after liver transplantation

Recurrence of hepatitis C virus (HCV) after liver transplantation is common and is associated with high blood levels of HCV RNA. Higher blood levels of HCV may promote body fluid expression of the virus. We tested 152 body fluid specimens from 33 patients with chronic hepatitis C, 21 of whom had undergone prior liver transplantation. All patients had hepatitis C viremia, as determined by a reverse-transcription polymerase chain reaction (PCR) to the 5' noncoding region. The virus was quantitated in serum by the branched chain DNA assay (bDNA). Body fluids (33 sputum, 33 saliva, 33 urine, 32 tear, 9 vaginal, and 12 semen samples) were analyzed using PCR for HCV RNA. Serum HCV RNA by bDNA in the posttransplantation group was 255 +/- 229 x 10(5) compared with 50 +/- 56 x 10(5) eq/mL in the patients who did not undergo transplantation (P = .01). All urine, tear, and semen specimens were negative for HCV RNA. Five of 21 (24%) posttransplantation patients had detectable HCV RNA using PCR in oral secretions compared with 0 of 12 patients who did not undergo transplantation (not statistically significant). However, 5 of 11 patients with serum HCV RNA by bDNA results greater than 150 x 10(5) eq/mL had positive RNA in oral secretions compared to 0 of 22 patients with bDNA less than 150 x 10(5) eq/mL (P = .01). Posttransplantation patients were more likely to have bDNA levels exceeding 150 x 10(5) eq/mL (11 of 21 v 1 of 12, P = .03). Patients within the first year of transplantation were particularly prone to viral RNA levels exceeding 150 x 10(5) eq/mL (8 of 9 v 3 of 12, P = .01). We conclude that HCV RNA can occasionally be detected using PCR in oral secretions after liver transplantation. This is more likely during the first year posttransplantation when blood levels of HCV RNA often exceed 150 x 10(5) eq/mL by the branched chain DNA assay. Whether or not these observations represent an increased risk of transmission of infection during the early posttransplantation period is not certain.

Need for reduction of cyclosporin dosage in renal transplant patients with hypertriglyceridemia but not hypercholesterolemia

Currently there is a paucity of data regarding the influence of high serum triglyceride levels on cyclosporin A (CyA) levels and dosing. We therefore undertook a retrospective study to determine the relationship of serum lipid levels to CyA levels and CyA dosages. Renal transplant patients at a 0.5-to-3-year post-transplant stage, with a stable CyA dosage, who were not on medications that affect CyA metabolism or renal function, were entered into the study. The CyA dosage was adjusted by clinicians to maintain whole blood. 12-h CyA trough levels between 200 and 250 ng/ml (monoclonal TDX method, which measures the parent compound). Forty-four patients qualified for the study. The data clearly indicated that high cholesterol levels (> 300 mg/dl and with normal triglyceride levels) did not influence the CyA levels or the dosages. Conversely, high triglyceride levels ( > 500 mg/dl) significantly reduced the amount of CyA required. A decreased clearance of CyA in the presence of hypertriglyceridemia led to high CyA levels in some patients. Reducing the CyA dosage to achieve levels between 200 and 250 ng/ml improved renal allograft function and decreased other side effects attributed to CyA toxicity. These studies indicate that high triglyceride levels, but not high cholesterol levels, increase CyA levels, which can lead to CyA toxicity.

Donor lazaroid pretreatment improves viability of livers harvested from non-heart-beating rats

BACKGROUND

Lazaroids are potent inhibitors of lipid peroxidation. Whether the compounds can benefit the liver procured from non-heart-beating donors (NHBDs) is unknown.

METHODS

Donor rats were pretreated with lazaroid U74006F (4.5 mg/kg) 1 hour before cardiac arrest, and transplantation was performed in the rats with donor cardiac arrest from 0 to 60, 100, 120, 140, and 160 minutes as lazaroid pretreated groups. The same number of liver transplantations were done in each paired control group without donor lazaroid pretreatment. Recipient survival rates, bile secretion, serum enzymes, and a lidocaine metabolism test were analyzed.

RESULTS

Donor lazaroid pretreatment significantly increased recipient 3-day survival rates in groups with 60, 100, and 120 minutes of warm ischemia and 7-day survival with 60 minutes of warm ischemia. Also, the pretreatment increased bile secretion and reduced serum aspartate aminotransferase and lactate dehydrogenase levels in the lazaroid-pretreated groups.

CONCLUSIONS

Donor U74006F pretreatment improves viability of livers procured from NHBDs.

The use of pronase-digested human leukocytes to improve specificity of the flow cytometric crossmatch

Two-color fluorescence cytometry (FCXM) has recently been introduced to improve the detection of anti-HLA antibodies that react to donor cells, especially in recipients receiving kidney allografts. Although this assay system is highly sensitive, it lacks specificity. Between 70% and 90% of potential kidney recipients with a positive FCXM would have been denied transplant if such an assay had been used alone to detect antidonor antibodies. Lack of specificity is principally due to normal or irrelevant IgG in aggregates or immune complexes binding to Fc gamma R receptors on lymphocytes including B cells and a significant subset of T cells. To circumvent this problem, we digested Fc gamma R receptors on lymphocytes with pronase. We present data demonstrating that pronase digestion of lymphocytes does not alter HLA antigenicity. In addition, pronased lymphocytes allow one to use either single- or two-color FCXM. With single-color FCXM, one can quantitate antibody reactivity to lymphocytes via a cursor (on the fluorescence histogram) that separates lymphocytes that do not bind to antibodies. We present data demonstrating that this modification renders FCXM highly sensitive and specific. In addition, one can discriminate between IgG and IgM antibodies that react to lymphocytes.

Hyperaluminemia associated with liver transplantation and acute renal failure

Iatrogenic aluminium toxicity is reported in a patient who underwent an orthotopic liver transplant and who had concomitant renal failure requiring hemodialysis. Following transplantation the patient developed a metabolic encephalopathy with only mildly elevated blood ammonia concentrations. During the period following transplantation the patient received massive infusions of albumin and was on oral feeding (vivonexten), both of which contained aluminium, as did the dialysis fluid. Hyperaluminemia and profoundly elevated liver tissue aluminium concentrations were observed. Treatment with desferrioxamine, a trivalent ion chelator, decreased the plasma aluminium concentrations with an improvement in the patient's mental status.

Evidence demonstrating poor kidney graft survival when acute rejections are associated with IgG donor-specific lymphocytotoxin

The current prospective investigation was conducted to determine whether development of IgG donor-specific lymphocytotoxins detected at the onset of acute rejections was predictive of a poor-prognosis acute rejection. Between January 1990 and August 1993, 206 kidney transplants were performed. Cadaver kidney recipients were managed with antilymphocyte globulin as induction therapy and all recipients (i.e., cadaver and living related donor kidneys) received triple immunosuppressive therapy, i.e., CsA, AZA, and prednisone. Rejections were treated with intravenous Solu-Medrol and OKT3. Presence of donor-specific IgG lymphocytotoxin was detected by using dithiothreitol-pretreated sera (obtained at onset of rejection) and frozen donor cells. In addition, percentage of panel reactive antibody was determined on this dithiothreitol-pretreated sera. Of the 82 patients with biopsy-proven acute rejections, 19 were found to have developed donor-specific IgG lymphocytotoxin and a marked increase in panel reactive antibody. One-year graft survival in this group was dismal (16%), despite OKT3 therapy. Over 90% of these patients lost their graft within 2 months of rejection diagnosis. In 63 recipients who had acute rejections without development of IgG anti-HLA antibody, 1-year graft survival was 72%. The majority of these patients lost their grafts from chronic rejection. No anti-HLA activity was found in patients who did not have rejection episodes. Based on this study, evidence indicates that assaying for IgG donor-specific antibody at time of rejection is a valuable tool for selecting a subset of patients with poor-prognosis acute rejections. Identifying this subset will become important as we enter an era of new immunosuppressive agents.

The lack of long-term detrimental effects on liver allografts caused by donor-specific anti-HLA antibodies

Recent reports indicate a higher incidence of both acute and chronic liver allograft rejection when, at the time of transplantation, the recipients serum contains donor-specific anti-HLA antibodies. From 9/89 to 5/91, 133 liver allografts were performed at our institution. Thirteen liver recipients had donor-specific IgG anti-HLA antibodies (complement-fixing) at the time of transplantation. In eleven patients, antibodies reacted to donor class I antigens while in 1 patient the donor-specific antibody had class II reactivity. Twelve patients have been followed for a minimum of 12 months (median 18 months, range 28-12 months). No hyperacute rejection was seen in any of the cases and four patients had acute rejections. Thus far only one of the twelve patients has biopsy evidence suggestive of chronic liver injury. The remaining have normal liver enzymes and bilirubin. Three of these twelve patients died (one from a myocardial infarction and the others from sepsis) accounting for a one-year graft survival of 75%. There was no significant statistical difference in the one-year graft survival in those recipients without donor-specific antibodies (i.e., 80.5%). In eight of the twelve patients, pretransplant preformed antibody level (PRA) was > 50%. In six of the thirteen patients donor-specific antibody was present at dilutions greater than 1:64. As previously reported, the donor-specific antibody disappeared from the serum posttransplant within hours and did not reappear. In vitro studies demonstrated no factor in portal or hepatic artery blood that could inhibit rabbit complement mediated lysis of anti-HLA antibodies. We conclude that it is not a contraindication to do liver transplants in the presence of donor-specific anti-HLA antibodies.

Human sphincter of Oddi motility and cholecystokinin response following liver transplantation

The reported incidence of sphincter of Oddi dysfunction following orthotopic liver transplantation has ranged from 3% to 7%. If sphincteric dysfunction is unrecognized, therapy may be inappropriate; when recognized, extensive surgery may be required. To prospectively identify patients with sphincteric dysfunction, we performed sphincter of Oddi motility studies through the t-tube tract three months after transplantation. Baseline sphincter motility and response to intravenous cholecystokinin were evaluated. The results of 10 subjects are reported; nine had normal basal sphincter pressure (16 +/- 5.8 mm Hg), and all had normal frequency (3.6 +/- 1/min), amplitude (86 +/- 31 mm Hg), and duration (4.5 +/- 1 sec) of phasic contractions. One subject had an elevated basal pressure (47 mm Hg). All, including the subject with elevated basal pressure, demonstrated a normal response to intravenous cholecystokinin with significant inhibition of phasic contraction frequency and amplitude. We demonstrate that simultaneous studies of the sphincter and duodenum can be obtained via the t-tube tract, providing the opportunity for prospective evaluation of sphincteric function. We conclude that sphincter of Oddi function usually remains normal following liver transplantation with choledochocholedochostomy.

Pancreas transplantation. An initial experience with systemic and portal drainage of pancreatic allografts

Pancreas transplantation has evolved dramatically since its introduction in 1966. As new centers for transplantation have developed, the evaluation of complications associated with pancreas transplantation has led to advances in surgical technique. Furthermore, surgical alterations of the pancreas resulting from transplantation (systemic release of insulin and denervation) are of unproven consequence on glucose metabolism. Since 1988, the authors have performed 21 transplants (16 combined pancreas/kidney, 3 pancreas alone, which includes 1 retransplantation, 1 pancreas after previous kidney transplant, and 1 "cluster") in 20 patients aged 18 to 49 years; mean, 35 +/- 1 years. Overall patient survival is 95%. Three pancreatic grafts failed within the first year because of technical failure; one additional pancreas was lost to an immunologic event on postoperative day 449, for an overall pancreatic graft survival of 81%. No renal grafts were lost. To evaluate causes of graft failure, demographic data were compared, which included age and sex of the donor and the recipient, operative time, intraoperative blood transfusion, and ischemic time of the graft. No statistically significant differences were found between groups except for ischemic time (11.7 +/- 6.4 hours for the technical success group versus 19.8 +/- 3.7 hours for the technical failure group; p less than 0.05 by unpaired Student's t test). Quadruple immunosuppression was used, which included prednisone, cyclosporine, azathioprine, and antilymphoblast globulin. A mean of 1.2 (range, 0 to 3) rejection episodes per patient occurred. Mean hospital stay was 24 +/- 11 days. Surgical and infectious complications were evaluated by comparing the technical success (TS) group (n = 17) with the technical failure (TF) group. Surgical complications in the TS group revealed a mean of 1.3 episodes per patient, whereas the TF group had 3.7 episodes per patient. The TS also had a reduced incidence of infectious complications compared with the TF (1.7 versus 4.3 episodes per patient). Cytomegalovirus was common in both groups, accounting for 11 infectious episodes, and occurred on a mean postoperative day of 38. Mean postoperative HbA1C levels dropped to 5 +/- 1% from 11 +/- 3%. The authors developed a new technique that incorporates portal drainage of the pancreatic venous effluent in three recipients. Preoperative metabolic studies disclosed a mean fasting glucose of 211 +/- 27 mg/dL and a mean stimulated glucose value of 434 +/- 41 mg/dL for all patients; the mean fasting insulin was 23 +/- 4 microU/mL.(ABSTRACT TRUNCATED AT 400 WORDS)

Childbearing after liver transplantation

Seventeen female patients who underwent orthotopic liver transplantation between June 1973 and June 1987 became pregnant 5 months to 11 years after transplantation. Immunosuppression was maintained with combinations of prednisone, cyclosporine, and azathioprine prior to and during pregnancy. One patient discontinued immunosuppression after knowledge of pregnancy, taking only azathioprine sporadically. Mean age at time of delivery was 26 years. Twelve patients had no alteration in liver function studies; 7 patients demonstrated mild or moderate enzyme elevations prior to delivery, with one case of rejection confirmed by percutaneous liver biopsy. Major problems related to pregnancy were hypertension, anemia, and hyperbilirubinemia. Twenty live births occurred (2 patients had 2 separate pregnancies, one patient had a set of twins); 13 were by cesarean section, 7 by vaginal delivery. Eleven of the 13 cesarean births were premature by gestational age. All vaginal births were term. Toxemia of pregnancy and early rupture of membranes were the principal indications for cesarean section. There were no congenital abnormalities or birth defects and all the children are surviving well. Fifteen of 16 children older than one year all have normal physical and mental development, with one child manifesting immature speech development. Four children are under one year, all with normal milestones thus far. Sixteen of the 17 mothers are alive from 2-18 years after transplantation; the only death was from a lymphoma, almost 4 years after transplantation and 2 1/2 years after delivery. This experience suggests that women undergoing liver transplantation can safely bear children despite an increased risk of premature cesarean births. The effect of chronic immunosuppression of female pediatric patients on their reproductive potential later in adulthood remains to be fully evaluated but the results so far are favorable.

A modified technique of orthotopic transplant of the kidney in rabbits

In this study kidneys were harvested from bred-for-research cats weighing 4 to 5 kg. General principles of donor bilateral nephrectomy en bloc with aorta, vena cava, renal vessels, and ureters were followed. After the harvest the grafts were placed in lactated Ringer slush. A cuff was prepared on the renal vein over a 10 French plastic tube. The aorta was divided and left in connection with the renal artery at each side. Twenty female checkered Flemish giant rabbits weighing 4.0-6.0 kg served as recipients. After premedication with 40 mg/kg of ketamine, anesthesia was maintained with repeated doses (every 10-15 min) of a 0.1-mL mixture of 5 parts ketamine and 1 part acepromazine diluted 50% in a normal saline. Arterial pressure, CVP, blood gases, and temperature were monitored. Through a limited midline incision a native left nephrectomy was performed. The venous anastomosis was performed with a cuff technique without clamping the vena cava (which causes severe hemodynamic instability); the anastomotic time was 2-3 min. The arterial anastomosis was performed with an end-to-side aorta-to-aorta anastomosis; the anastomotic time was 5 to 7 min. There were no episodes of venous or arterial thrombosis. The donor procedure took approximately 40 min, and the backtable preparation of the graft an additional 45 to 60 min. Preparation of the recipient for the anastomosis took 15 min and the anastomotic time (warm ischemia) was 13 +/- 5 min. In this model suitable for xenograft research the duration of the surgery in the recipient has been greatly reduced because of (1) the previous backtable preparation of the graft, and (2) the cuff technique used for venous anastomosis. The present anesthesia regimen and careful hemodynamic monitoring were also important in the success of this model.

Use of autoperfusion for distant procurement of heart-lung allografts

Heart-lung transplantation has been limited to on-site organ procurement because current methods of lung preservation are unreliable for periods in excess of one hour. A method of dynamic heart-lung preservation has been evaluated as a possible means for distant procurement for human transplantation. Canine and bovine heart-lung blocks were removed and preserved by autoperfusion for periods of two to nine hours. The key features of the method included normothermic coronary autoperfusion with donor blood by an autoregulating beating heart, and a stabilizing reservoir bag interposed between the donor aorta and the right atrium. The reservoir is positioned one meter above the aortic valve, and determines the pressure in the aorta. Flow from the bag to the right heart dictates venous return, pulmonary blood flow, and ventricular stroke volume. The lungs are ventilated with room air and 5% to 10% of CO2, at 4 liters/minute. Normothermia is ensured by immersion of the heart-lungs block in a temperature controlled crystalloid bath. Eleven canine and eight bovine heart-lung blocks were evaluated for two to nine hours. Lung function was excellent during this period, and cardiac output did not decline from pre-harvest levels. Five heart-lung allografts were transplanted after an average of four hours of autoperfusion and all functioned satisfactorily. All animals could be weaned from the extracorporeal circulation support. Two to three hours later, cardiac outputs and arterial pO2 were normal. The peak airway pressures averaged 29 cm H2O.(ABSTRACT TRUNCATED AT 250 WORDS)