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Background: Allograft coronary vasculopathy is a major cause of death beyond the first year after cardiac transplantation. The aim of this study was to review our experience with percutaneous coronary intervention (PCI) with stents in cardiac transplant recipients. Methods: We identified patients who were treated with PCI using stents. Patient characteristics, procedure information and clinical outcomes were assessed for these patients by review of their medical records. We also compared results for those who had bare metal stents vs those who had drug-eluting stents. Results: Forty patients from our program’s 865 cardiac transplant recipients received a total of 78 coronary stents. There were 35 males (87.5%) and 5 females (12.5%). The indication for PCI was progressive asymptomatic coronary vasculopathy in 18 patients (45%), angina in 5 (12.5%), acute myocardial infarction (MI) in 4 (10%) and congestive heart failure (CHF) in 6 (15%). Primary success (<50% residual stenosis) was obtained in 71 (91%) of 78 stents. During the mean follow-up of 40.8 ± 34.5 months, 6 patients died (15%) and 2 (5%) were re-transplanted. There was a lower rate of re-stenosis with drug-eluting stents (2 of 13, 15%) compared with bare metal stents (20 of 65, 31%), although this difference was not statistically significant (p = 0.27). Conclusions: In cardiac transplant recipients, PCI with stents can be performed with high rates of primary success. Restenosis rates are higher compared with PCI in native coronary arteries. A trend toward less restenosis with drug-eluting stents was observed, which needs to be confirmed in larger studies. [Copyright &y& Elsevier]

Background: β-Blockers are frequently used after cardiac transplantation for blood pressure control. There is no well-known interaction between β-blockers and cyclosporine A (CsA). However, recent reports have suggested that carvedilol, but not metoprolol, modulates P-glycoprotein (P-gp), a membrane protein that regulates CsA absorption. We evaluated the effects of carvedilol and metoprolol on CsA level when initiated in cardiac transplant recipients. Methods: Using our cardiac transplant database, we identified patients who were started on either carvedilol or metoprolol for blood pressure control. We then compared their CsA doses and levels before and within 2 weeks after the initiation of β-blocker therapy. Results: We found 20 patients taking metoprolol and 12 patients taking carvedilol. With initiation of metoprolol, CsA level decreased in 12 patients and increased in 8 patients. The mean CsA level before and after metoprolol initiation was 236 ng/ml and 253 ng/ml, respectively (p = 0.50). In an attempt to maintain a therapeutic CsA level, the mean CsA dose was not significantly adjusted (from a mean of 293 mg/day to a mean of 294 mg/day; p = 0.92). In the Carvedilol Group, CsA level increased in 10 of 12 patients. The mean CsA level before the initiation of carvedilol was 257 ng/ml. The mean CsA level after carvedilol initiation was 380 ng/ml (p = 0.009). In an attempt to maintain a therapeutic CsA level, the mean CsA dose was reduced by 10%, from a mean of 319 mg/day to a mean of 288 mg/day (p = 0.004). Conclusion: Carvedilol, but not metoprolol, was associated with a significant increase in CsA levels after initiation in cardiac transplant recipients. Although carvedilol and CsA do not interact at the level of cytochrome P450 system, it appears that carvedilol influences CsA levels through its effects on P-gp. An average reduction of 10% is necessary on the CsA dose upon initiation of carvedilol, and close follow-up of the level is essential. [Copyright &y& Elsevier]

Background: Growing evidence suggests worse cardiac allograft vasculopathy and mortality in patients with asymptomatic antibody-mediated rejection (AMR). Debate continues about whether therapeutic intervention is warranted to avoid adverse outcomes. In this study we examine the course of individual episodes of untreated asymptomatic AMR on follow-up endomyocardial biopsy (EMB). Methods: The U.T.A.H. Cardiac Transplant Program database was queried for transplant recipients between 1985 and 2009 who survived beyond 1 year and had at least 1 episode of lone AMR with a follow-up EMB. All EMBs were screened for AMR by immunofluorescence and graded for severity. Data were analyzed based on time from transplant (early, ≤12 months; late, >12 months). Results: Nine hundred fifty-eight patients with a total of 15,448 biopsies qualified for the study. Average age at transplant was 46.7 years; 13% of the patients were female. Within the first year post-transplant, asymptomatic AMR was diagnosed in 13.6% of biopsies compared with 5.2% beyond 1 year. AMR resolved in 65% (early) vs 75% (late) on follow-up EMB. More severe AMR was less likely to improve regardless of time from transplant. Furthermore, after an episode of AMR had resolved, the recurrence rate at 3, 6 and 12 months was 44%, 50.1% and 56.2%, respectively. Conclusions: The incidence of AMR is higher in the first year post-transplant and the likelihood of resolution is less on follow-up EMB, especially when more severe. A small but significant number of cases became worse or did not change. These new findings may be helpful in planning future studies that test whether therapeutic interventions on asymptomatic AMR favorably impact outcomes. [Copyright &y& Elsevier]

Background: Recent efforts are being undertaken to update and refine current diagnostic criteria for antibody-mediated rejection (AMR) in heart transplantation. We believe that the appropriate reactants are those that best predict the adverse consequences of AMR and therefore tested various models using different reactants to find the best predictors of cardiovascular mortality in pathologically defined AMR. Methods: The study group included only patients in whom all immunofluorescence antibodies of interest had been tested on biopsy specimens obtained after 2002 when C4d was routinely added. We analyzed our data using 3 Cox proportional hazard models with time-varying covariates using an end point of cardiovascular mortality, as previously defined. Results: In 3,712 biopsy specimens from 422 patients, the 2-antibody model achieved a value of R 2 = 0.930 using C3d and C4d antibodies alone. A model that used 4 antibodies—C3d, C4d, human leukocyte antigen-D related (HLA-DR) and fibrin—was superior (R 2 = 0.988). The model that best predicted cardiovascular mortality included all 6 antibodies: HLA-DR, immunoglobulin (Ig) G, IgM, C3d, C4d, and fibrin (R 2 = 0.989). The models using 4 or 6 antibodies were significantly superior to the model using only C3d and C4d (for each interaction, p < 0.0001). Conclusions: The combination of complement components, HLA-DR and fibrin, is valuable in defining AMR in patients at risk for allograft loss from cardiovascular causes. Fibrin is particularly important for detecting the presence of severe AMR, with a high likelihood of poor long-term patient outcome. [ABSTRACT FROM AUTHOR]

Background: Little has been reported on the clinical significance of asymptomatic antibody-mediated rejection (AMR) alone or mixed rejection (MR), defined as concurrent cellular rejection (CR) and AMR in heart transplantation. In this study, we examined whether a differential impact on cardiovascular mortality (CVM) existed when comparing asymptomatic AMR, to stable MR or CR. Methods: The Utah Transplantation Affiliated Hospitals (UTAH) Cardiac Transplant Program pathology database of all heart transplant recipients between 1985 and 2004 was queried. Patients were classified as cellular, antibody-mediated, or mixed rejectors based on their predominant pattern of rejection type in the first three months post-transplant. Kaplan-Meier survival curves were fit to each of the three groups and analyses were adjusted for age at the time of transplant, gender, and underlying primary cardiac disease. Results: Eight hundred and sixty nine heart transplant recipients qualified for analysis. Over the study period, patients with asymptomatic AMR or stable MR patterns had significantly worse CVM when compared to patients with stable CR pattern (AMR, 21.2%; MR, 18.0%; CR, 12.6%; AMR vs. CR, p = 0.009; MR vs. CR, p = 0.001). In contrast, CVM was comparable in patients with asymptomatic AMR or stable MR patterns (p = 0.9). Conclusions: Asymptomatic or subclinical AMR and MR are clinically relevant, should be recognized, and deserve consideration for therapeutic intervention in hopes of avoiding adverse outcomes. [Copyright &y& Elsevier]

Background: The current International Society for Heart and Lung Transplantation (ISHLT) diagnostic criteria for antibody-mediated rejection (AMR) designate AMR as either absent (AMR 0) or present (AMR 1), without grading its severity. Yet, the extent of histologic and immunofluorescence (IF) findings of AMR varies across endomyocardial biopsies (EMBs). In this study, we hypothesized that the severity of AMR, as assessed on EMBs, correlates with cardiovascular mortality in heart transplant recipients. Methods: All EMBs from 1985 to 2005 were evaluated. Biopsy specimens were uniformly studied by light microscopy and IF early post-transplant. A comprehensive vascular score (V1: no AMR, to V5: severe AMR) was prospectively assigned to each EMB, based on severity of both histologic and IF findings. Univariate Cox proportional hazards regressions were performed using indicators of vascular scores alone, combined, and cumulatively. Results: Nine hundred six patients were transplanted and included in the study. Mean age was 46.6 ± 15.5 years and 82% were male. A total of 26,236 EMBs comprised the study data. As expected, histologic and immunopathologic findings of AMR varied in severity. An incremental risk of cardiovascular mortality was found with more severe AMR whether vascular scores were analyzed individually (p = 0.001), in combination (p = 0.01) or cumulatively (p = 0.006). Conclusions: The severity of AMR on EMBs correlates with an incremental cardiovascular mortality risk after heart transplantation, suggesting that AMR should be viewed as a spectrum rather than just as present or absent. Supplementing the ISHLT AMR diagnostic guidelines with a consensus severity scale is warranted. [Copyright &y& Elsevier]

Background: The International Society for Heart and Lung Transplantation (ISHLT) recently established a diagnostic scheme for antibody-mediated rejection (AMR). Currently, however, confirmatory immunohistochemistry studies are recommended only if AMR is clinically or histologically suspected. In this study, we examine whether a pattern of repetitive AMR occurred early enough after transplantation to warrant prospective immunohistochemistry screening in all recently transplanted recipients. Methods: We queried our pathology database of adult and pediatric endomyocardial biopsies (EMBs) from 1985 to 2005. All EMB specimens were prospectively studied by immunofluorescence in the early post-operative period. AMR was defined as the presence of complement and immunoglobulin deposits on frozen section. Only patients classified as antibody-mediated rejectors (≥3 episodes of AMR) were included. Cumulative incidence and time from transplant to first and third AMR episodes were obtained. Results: Three hundred seventy-five of 870 heart transplant recipients had ≥3 episodes of AMR. Mean age of recipients was 45.6 years and 78% were male. A total of 19,569 EMBs comprised the study data. By 100 days post-transplant, 85% of patients had their first and 54% their third AMR. In addition, patients showed a clear trend of early clustering of AMR-positive biopsies. Results were similar regardless of whether or not muromonab-CD3 (Orthoclone OKT3) induction was used. Conclusions: We advocate early immunohistochemical surveillance testing for AMR to supplement the diagnostic algorithm established by the ISHLT, because a pattern of AMR becomes manifest soon after transplantation. This change will allow earlier detection of asymptomatic AMR and may prompt changes in immunosuppression strategies to avoid adverse outcomes. [Copyright &y& Elsevier]