Combined heart-liver transplantation in the MELD era: do waitlisted patients require exception status?

Combined heart-liver transplant (HLT) is a viable therapy for patients with concomitant end-stage heart and liver failure. Using data from the United Network for Organ Sharing database, we examined the cumulative incidences of transplant and mortality in waitlisted candidates for HLT, isolated heart transplant (HRT) and isolated liver transplant (LIV) in the Model for End-Stage Liver Disease era. The incidence of waitlist mortality was higher in HLT candidates than in HRT candidates (p = 0.001, 26% vs. 12% at 1 year) or LIV candidates (p = 0.005, 26% vs. 14% at 1 year). These differences persisted after stratifying by disease severity. Posttransplant survival was not significantly different between HLT and HRT recipients or between HLT and LIV recipients. In a multivariable model, undergoing HLT was associated with enhanced survival for HLT candidates (hazard ratio, 0.41; confidence interval, 0.21-0.79; p = 0.008), but undergoing HRT alone was not. Interestingly, 90% of HLT recipients were allocated an organ locally, compared to 60% of HRT candidates and 73% of LIV candidates (both p < 0.001). These data suggest that the current cardiac and liver allocation systems may underestimate the risk of death for patients with concomitant end-stage heart and liver failure on the HLT waitlist.

Heart and combined heart-kidney transplantation in patients with concomitant renal insufficiency and end-stage heart failure.

In patients with end-stage heart failure (ESHF) who are candidates for isolated heart transplant (HRT), dialysis dependence (DD) is considered an indication for combined heart-kidney transplantation (HKT). HKT remains controversial in ESHF transplant candidates with nondialysis-dependent renal insufficiency (NDDRI). Using United Network for Organ Sharing data, we examined the cumulative incidences of transplant and mortality in patients with DD and NDDRI waitlisted for HKT or HRT. In all groups, 3-month waitlist mortality was dismal: 31% and 21% for HRT- and HKT-listed patients with DD and 12% and 7% for HRT- and HKT-listed patients with NDDRI. Five-year posttransplant survival was improved in HKT recipients compared with HRT recipients for both patients with DD (73% vs. 51%, p<0.001) and NDDRI (80% vs. 69%, p<0.001). Likewise, multivariable analysis associated HKT with better outcomes than HRT in HKT-listed patients, although both improved survival. These data argue strongly for HKT in ESHF transplant candidates with DD. However, in patients with NDDRI, HKT must be weighed against the possibility of renal recovery with isolated HRT. Whether HRT (followed by a staged kidney transplant in patients who do not recover renal function after HRT), as opposed to HKT, maximizes organ benefit for patients with NDDRI and ESHF requires assessment. Nevertheless, given their dismal waitlist outcomes and excellent posttransplant results, we suggest that patients with DD and NDDRI with ESHF be considered for early listing and transplant.

An analysis of the toxic actions of purified streptolysin O on the isolated heart and separate cardiac tissues of the guinea pig.

The response of isolated guinea pig hearts to perfusion with purified streptolysin O is characterized by a rapid, but transient, decrease in rate and amplitude of contraction; these reactions are superimposed upon a gradual, irreversible, loss of ventricular contractility. At ventricular standstill, the atria continue to beat spontaneously in a normal way. Isolated ventricle strips prepared from such preparations can be driven electrically, and their behavior is functionally indistinguishable from that of similar preparations made from normal hearts. Tests on spontaneously beating isolated atrial pairs show that the toxin induces a dose-dependent, reversible, decline in rate and amplitude which is accompanied by a marked, but transient, increase in the velocity of repolarization of the intracellular potential. The atrial reactions were completely blocked by atropine and potentiated by eserine. Acetylcholine was detected in the perfusates obtained by incubating a large pool of atrial tissue with active toxin, supporting the inference that the transient mechanical and electrophysiological reactions to toxin might be consequences of the release of acetylcholine from these tissues by the active toxin. Control studies showed that only the active toxin had the capacity to induce the cardiac responses. The toxin was active only in the reduced but not the oxidized form. The effects of the active toxin were modified if it were heated prior to challenge, and they could be neutralized by specific antiserum and inhibited by cholesterol. Since the driven ventricle strip was mechanically and electrophysiologically insensitive to streptolysin O, the irreversible changes in the whole heart must have occurred because of a defect in the atrioventricular conduction system.

Transplantation tolerance in adult rats using total lymphoid irradiation: permanent survival of skin, heart, and marrow allografts.

Lewis rats given total lymphoid irradiation (TLI) accepted bone marrow allografts from AgB-incompatible donors. The chimeras showed no clinical signs of graft-versus-host disease. Skin allografts from the marrow donor strain survived for more than 150 days on the chimeras. However, third-party skin grafts were rejected promptly. Although heart allografts survived more than 300 days in Lewis recipients given TLI and bone marrow allografts, detectable levels of chimerism were not required for permanent survival.

Twenty-year survivors of heart transplantation at Stanford University.

Human heart transplantation started 40 years ago. Medical records of all cardiac transplants performed at Stanford were reviewed. A total of 1446 heart transplantations have been performed between January 1968 and December 2007 with an increase of 1-year survival from 43.1% to 90.2%. Sixty patients who were transplanted between 1968 and 1987 were identified who survived at least 20 years. Twenty-year survivors had a mean age at transplant of 29.4 +/- 13.6 years. Rejection-free and infection-free 1-year survivals were 14.3% and 18.8%, respectively. At their last follow-up, 86.7% of long-term survivors were treated for hypertension, 28.3% showed chronic renal dysfunction, 6.7% required hemodialysis, 10% were status postkidney transplantation, 13.3% were treated for diabetes mellitus, 36.7% had a history of malignancy and 43.3% had evidence of allograft vasculopathy. The half-life conditional on survival to 20 years was 28.1 years. Eleven patients received a second heart transplant after 11.9 +/- 8.0 years. The most common causes of death were allograft vasculopathy (56.3%) and nonlymphoid malignancy (25.0%). Twenty-year survival was achieved in 12.5% of patients transplanted before 1988. Although still associated with considerable morbidity, long-term survival is expected to occur at much higher rates in the future due to major advances in the field over the past decade.

Role of tachycardia as an inotropic stimulus in man.

We examined the inotropic effect of tachycardia in nine postsurgical aortocoronary bypass graft patients (with intact cardiac innervation) and nine cardiac allograft recipients (with denervated hearts). The changes in stroke volume (SV) and velocity of circumferential fiber shortening (VCF) which accompany sudden increases and decreases in atrial pacing frequency were determined by computer-aided fluoroscopic analysis of the motion of surgically implanted midwall myocardial markers. Because the first beat after a change in rate retains the frequency characteristics of the preceding rate, we compared the first posttachycardia beat with control beats and late tachycardia beats with the first tachycardia beat; afterload and preload for each pair of beats were similar. For an increase in heart rate of 50 beats/min, SV and VCF rose 79 and 64% from the first tachycardia beat to late tachycardia beats, and SV and VCF rose 8 and 35% from control beats to the first posttachycardia beat in the innervated group. Responses in the denervated group were not significantly different from those in the innervated group. The degree of the inotropic response was positively correlated with the magnitude of the increase in heart rate (r = 0.91). The decay in augmented contractility after decreasing the rate back to control levels fits an exponential relationship with a mean t((1/2)) of 1.7 s. Thus, in conscious man, increases in heart rate represent a positive inotropic stimulus, independent of other factors influencing ventricular performance and unaffected by neural innervation, and should be considered when changes in cardiac function are interpreted during serial studies or after drug administration.

Thimet oligopeptidase (EC 3.4.24.15) activates CPI-0004Na, an extracellularly tumour-activated prodrug of doxorubicin.

CPI-0004Na is a tetrapeptidic extracellularly tumour-activated prodrug of doxorubicin. The tetrapeptide structure ensures blood stability and selective cleavage by unidentified peptidase(s) released by tumour cells. The purpose of this work was to identify the enzyme responsible for the first rate-limiting step of CPI-0004Na activation, initially attributed to a 70 kDa acidic (pI=5.2) metallopeptidase active at neutral pH that was subsequently purified from HeLa cell homogenates. Two electrophoretic bands were isolated and identified by matrix-assisted laser desorption ionisation-time of flight (MALDI-tof) and electrospray ionisation-quadrupole-time of flight (ESI-Q-tof) mass spectrometry as thimet oligopeptidase (TOP). The identity of the CPI-0004Na activating enzyme and TOP was further supported by the similar substrate specificity of the purified enzyme and recombinant TOP, by thiol stimulation of CPI-0004Na cleavage by cancer cell conditioned media (unique characteristic of TOP) and by the inhibition of CPI-0004Na activation by specific inhibitors or immunoprecipitation. Although other enzymes can be involved, TOP clearly appears to be a likely candidate for extracellular activation of the CPI-0004Na prodrug.

Selective decrease of the viability and the sterol content of proliferating versus quiescent glioma cells exposed to 25-hydroxycholesterol.

The effects of 25-hydroxycholesterol (25-OHC), a potent inhibitor of sterol synthesis, on the growth, viability, and sterol content of C-6 rat glioma cells have been studied. Suppression of 3-hydroxy-3-methylglutaryl coenzyme A reductase activity and sterol synthesis in cells that were proliferating in medium supplemented with lipoprotein-poor fetal calf serum caused an arrest of growth after 24 hr. Prolonged incubation of serum-supplemented cells with 25-OHC resulted in a loss of morphological integrity and an 80% decline in cell viability, determined by trypan blue dye exclusion. In contrast, C-6 cells that were induced to enter a quiescent state by removal of serum from the medium remained viable and morphologically differentiated in the presence of 25-OHC. Following the addition of whole fetal calf serum to the medium, serum-free cells that had been incubated with 25-OHC for 3 days were able to resume proliferation. the selective killing of proliferating C-6 glioma cells by 25-OHC was correlated with a 45 to 50% decline in the sterol/phospholipid molar ratio, whereas the sterol/phospholipid ratio in the quiescent cells was not affected by 25-OHC. The results suggest that inhibitors of sterol synthesis may have potential as agents that might selectively decrease the growth and viability of glioma cells in the central nervous system without detriment to the normal nondividing neural cells.

Changes in synthesis of sterols and fatty acids associated with inhibition of growth of L-M cells at high cell density.

The relationship between cell density and de novo synthesis of sterols and fatty acids has been studied in monolayer cultures of L-M cells grown in serum-free medium. Incorporation of radioactivity from [14C] acetate or 3H2O into sterols and fatty acids declined sharply as cultures approached stationary phase. The activities of 3-hydroxy-3-methylglutaryl-CoA reductase and 3-hydroxy-3-methylglutaryl-CoA synthase declined in conjunction with the decrease in sterol synthesis; however, the activity of acetoacetyl-CoA thiolase did not decrease until after sterol synthesis had begun to decline. The magnitude of the initial decline in reductase activity was not diminished when activation of latent enzyme activity was prevented by addition of fluoride to cell homogenates. The diminution in the rate of fatty acid synthesis at high cell density was accompanied by a decrease in the activity of fatty acid synthetase, whereas the activity of acetyl-CoA carboxylase increased slightly. The data suggest that lipogenesis is regulated in coordination with the changes in the rate of cell proliferation that occur when L-M cells attain a high density in monolayer culture. Moreover, these studies establish the feasibility of using the L-M cell culture system to investigate the relationship between cell density and the enzymatic regulation of lipogenesis.

Histologic predictors of acute cardiac rejection in human endomyocardial biopsies: a multivariate analysis.

To identify specific histologic abnormalities that could predict early cardiac rejection before the development of myocyte necrosis, 167 consecutive endomyocardial biopsy samples from 18 cardiac transplant recipients were retrospectively analyzed and 17 histologic variables were semiquantitatively graded from 0 to 3. Forty-five biopsy samples contained foci of myocyte necrosis and were labeled Rejectors. The two samples immediately preceding Rejector biopsies were labeled Predictors (n = 44). All remaining samples were labeled Others (n = 78). Endocardial and interstitial infiltrates, interstitial mononuclear cells, pyroninophilic mononuclear cells, polymorphonuclear leukocytes and other cells (eosinophils and plasma cells) were significantly increased in graded severity in Rejector biopsy samples as compared with Predictors or Others (p less than 0.001, ANOVA testing). These variables cannot distinguish Predictor biopsy specimens from Others. On the other hand, interstitial edema, perivascular karyorrhexis and perivascular infiltrate with intermyocyte extension are histologic abnormalities that can distinguish Predictor biopsy samples from Others (p less than 0.001, ANOVA testing). Multiple logistic regression analysis indicates that the relative risk of developing myocyte necrosis when a biopsy sample contains interstitial edema is 8.1. With perivascular infiltrate with intermyocyte extension in addition, the relative risk is 41.4. In summary, three histologic abnormalities have been identified that help predict the future development of myocyte necrosis within the next two endomyocardial biopsies. Biopsy specimens with these abnormalities probably represent early cardiac rejection before the development of myocyte necrosis.

Immediate improvement of dysfunctional myocardial segments after coronary revascularization: detection by intraoperative transesophageal echocardiography.

To ascertain the immediate effects of coronary artery bypass grafting on regional myocardial function, intraoperative transesophageal two-dimensional echocardiograms were obtained in 20 patients using a 3.5 MHz phased array transducer at the tip of a flexible gastroscope. Cross-sectional images of the left ventricle were obtained at multiple levels before skin incision and were repeated serially before and immediately after cardiopulmonary bypass. Using a computer-aided contouring system, percent systolic wall thickening was determined for eight anatomic segments in each patient at similar loading conditions (four each at mitral and papillary muscle levels). Of the 152 segments analyzed, systolic wall thickening improved from a prerevascularization mean value (+/- SEM) of 42.7 +/- 2.9% to a postrevascularization mean value of 51.6 +/- 2.6% (p less than 0.001). Thickening improved most in those segments with the worst preoperative function (p less than 0.001). Chest wall echocardiograms obtained 8.4 +/- 2.3 days after operation showed no deterioration or further improvement in segmental motion compared with transesophageal echocardiograms obtained after revascularization. Thus: regional myocardial function frequently improves immediately after bypass grafting, with increases in regional thickening being most marked in those segments demonstrating the most severe preoperative dysfunction, and this improvement appears to be sustained; and in some patients, chronic subclinical ischemic dysfunction is present which can be improved by revascularization.

The p39 promoter of minute virus of mice directs high levels of bovine growth hormone gene expression in the bovine papilloma virus shuttle vector.

The promoter of the capsid-coding genes of the autonomous parvovirus minute virus of mice (MVM) is shown to drive high levels of expression of the heterologous bovine growth hormone (bGH) gene in a bovine papilloma virus (BPV)-based shuttle vector. The expression of bGH directed by the MVM p39 promoter was, on average, higher than that obtained from the widely used metallothionein promoter. These results indicate that the MVM-p39/BPV shuttle vector will be generally useful for the high-level expression of heterologous genes.

High-level expression of the bovine growth hormone gene in heterologous mammalian cells.

The gene coding for bovine growth hormone (bGH) was isolated from a lambda-phage library constructed using bovine pituitary DNA partially digested with MboI. Expression of this gene transfected into mouse and monkey cells was studied. CV-1 monkey cells transfected with simian virus 40 (SV40) vectors containing the intact bGH gene, including the putative promoter region, did not express bGH. However, replacement of the bGH promoter with the mouse metallothionein-I (MT) promoter resulted in high-level synthesis and secretion of bGH. These results show that the bGH promoter functions poorly in CV-1 cells but CV-1 cells process and translate the bGH mRNA accurately. The MT-bGH chimeric gene was used to establish permanent bGH-secreting mouse C127 cell lines using the 69% transforming fragment of bovine papilloma virus (BPV) as the vector. One such cell line produced high levels of bGH and secreted it into the medium efficiently. Secreted bGH is processed accurately and is bioactive as judged by its ability to bind to rabbit liver membrane preparations.

Cardiac papillary fibroelastoma and stroke. Echocardiographic diagnosis and guide to excision.

Cardiac papillary fibroelastomas are rare and have been considered a "benign," incidental finding. With two-dimensional echocardiography, these tumors can now be readily diagnosed. A young male patient who had a stroke due to a mitral valve papillary fibroelastoma is described. In this patient, not only did preoperative echocardiography establish the diagnosis, but intraoperative transesophageal two-dimensional echocardiography was utilized to guide tumor excision.

The utility of annual surveillance bronchoscopy in heart-lung transplant recipients.

Bronchoscopy with transbronchial biopsy (TBBx) and bronchoalveolar lavage (BAL) has an appreciable yield in detecting asymptomatic abnormalities in heart-lung transplant recipients (HLTR) during the early postoperative period. The utility of annual surveillance procedures has not been critically evaluated. We reviewed all annual bronchoscopies performed on 29 HLTR to determine the frequency of asymptomatic abnormalities. Surveillance bronchoscopies (SB) were performed on asymptomatic subjects with unchanged lung function compared with baseline. Surveillance/clinical bronchoscopies (SCB) were those performed in patients with stable decrements in lung function. Nineteen patients underwent 48 SB and 8 had 18 SCB. Five of 15 (33%) SB performed at one year yielded an abnormal TBBx (1 grade 2 acute rejection [AR], 1 grade 1 AR, 1 grade 1 AR with obliterative bronchiolitis [OB] and 2 Pneumocystis carinii pneumonia). At 2 or more years, TBBx was abnormal in 2 of 33 (6%, p = 0.024 compared with first year TBBx) (1 grade 1 AR, 1 lymphocytic bronchiolitis). Pathogens were identified in BAL in 19 (40%) SB. Fourteen (78%) SCB were abnormal. Nine (50%) revealed an abnormal TBBx (all OB), but only 2 (11%) of these altered patient management. Seven (39%) demonstrated pathogens in BAL. We conclude that in HLTR (1) surveillance TBBx rarely yields positive findings 2 or more years posttransplant, (2) surveillance TBBx seldom alters management in patients with stable decrements in lung function, and (3) BAL is useful to screen for potential pathogens.

Sequential orthotopic heart transplantation in man.

Between January 1968 and March 1980, 202 hearts had been transplanted into 185 patients at Stanford University Medical Center. Occasionally, patients after transplantation develop myocardial failure which is amenable only to retransplantation. Sixteen patients underwent initial orthotopic allograft using standard techniques. Eight patients developed accelerated arteriosclerotic coronary disease, six had unrelenting rejection, and two had donor heart dysrrhythmia or right ventricular failure requiring retransplantation. One patient required a third transplant because of donor left ventricular ischemia. All sequential transplants were managed similarly to the primary transplant. Of the initial transplant hearts at risk, 60% survived for more than 1 year, and 57% survived for more than 2 years. These results are similar to those of patients not requiring retransplantation. Of the secondary transplant hearts at risk, 31% survived for more than 1 year and 29% survived for more than 2 years. The severity of infection and/or rejection contributed most significantly to secondary heart transplant mortality. Sequential orthotopic cardiac transplantation offers an acceptable alternative to patients with allograft failure. Survival is not as favorable as with initial transplantation because of the prolonged immunosuppression during sequential transplantation.

Pathogenesis and prevention of graft arteriosclerosis in an experimental heart transplant model.

Accelerated graft arteriosclerosis is a major cause of death in human heart transplantation. Despite many investigations, the pathogenesis of this disease remains undetermined and its control inadequate. In this study using a rat heart transplant model and cyclosporin A, a new immunosuppressant, acute rejection was prevented but arteriosclerotic-like vessel disease still developed consistently as early as 20 days postoperatively. The combination of cyclosporin A and dipyridamole prevented the development of this vessel disease in transplanted hearts at 20 and 50 days postoperatively. Sulfinpyrazone and cyclosporin A reduced but did not prevent the disease. These findings suggest that immunologically induced graft arteriosclerosis can be prevented in transplanted rat hearts by the combination of cyclosporin A and dipyridamole.

Combination thalidomide and cyclosporine for cardiac allograft rejection. Comparison with combination methylprednisolone and cyclosporine.

Combination CsA with corticosteroids is the most commonly used maintenance immunosuppressive regimen after cardiac transplantation, although their high-toxicity profiles frequently limit their clinical benefit. Immunosuppressive agents that would act synergistically with CsA but without the toxicity profile of corticosteroids would be clinically useful. Thalidomide was removed from the market due to its teratogenic effects, although it has known immunomodulatory activity. The purpose of this study was (1) to determine whether maintenance immunosuppression with thalidomide and subtherapeutic doses of CsA can help prevent rat cardiac allograft rejection; and (2) to compare its synergism with CsA to the commonly used corticosteroid, methylprednisolone. ACI-LEW allografts were all treated with subtherapeutic doses of CsA (10 mg/g/day, s.c.) for 4 days. When CsA was then discontinued, severe rejection developed by posttransplant day 14. Group 1 received CsA alone. Group 2 received in addition oral thalidomide 100 mg/day for 14 days. Groups 3, 4, and 5 received CsA and methylprednisolone (low dose: 0.2 mg/kg/day s.c.; moderate dose: 2.0 mg/kg/day s.c.; and high dose: 20 mg/kg/day s.c. Twelve histologic parameters of rejection were semiquantitatively graded 0-4, and total pathology scores were determined. The combination of thalidomide and subtherapeutic CsA significantly reduced the severity of myocardial necrosis, interstitial inflammation, interstitial edema, and the total pathology score. Thalidomide was found to be equally as effective as low-, moderate-, and high-dose methylprednisolone. The results of this study suggest the potential clinical role of CsA and thalidomide in maintenance immunosuppressive regimens, thereby avoiding the use of corticosteroids.

Tissue-specific differences in the establishment of tolerance. Tolerogenic effects of lung allografts in rats.

With the increasing frequency of transplantation of two or more organs into a single recipient, it has become evident that different organs are rejected with different kinetics. In this study the kinetics of skin, lung, and heart allograft rejection were compared in a rodent model. To study the influence of different allografts on the recipient's immune system, simultaneous or sequential skin, lung, or heart transplants were performed in various combinations, using DA rats as recipients for PVG allografts. Recipients receiving primary allografts were treated postoperatively with ten doses of cyclosporine (CsA) or preoperatively with 4 doses of rabbit antirat thymocyte globulin (ATG). Subsequent transplants were performed a minimum of 40 days later without additional immunosuppression. All primary skin allografts and 60% of primary lung allografts were rejected, while 100% of the heart allografts were accepted indefinitely. Recipients of primary skin allografts rejected subsequent skin, lung, or heart allografts with accelerated kinetics. Recipients of primary heart allografts accepted subsequent skin, lung, and heart allografts indefinitely without further immunosuppression. Surprisingly, animals that had rejected a primary lung allograft accepted subsequent skin or heart allografts indefinitely. Simultaneously transplanted skin and lung allografts were concordantly rejected. However, these animals accepted a subsequent heart allograft indefinitely, suggesting a strong tolerizing effect of lung allografts. Our results indicate that tissue-specific differences are critical, not only in determining acceptance or rejection of a primary allograft but also in determining the fate of subsequent allografts.