Improved Survival With Statins, Angiotensin Receptor Blockers, and Steroid Weaning After Heart Transplantation

Infectious complications after heart transplantation in patients screened with gene expression profiling

BACKGROUND

The risk of infection after heart transplantation is highest within the first year and represents the leading cause of early mortality. In this cohort of patients enrolled in the Outcomes AlloMap Registry (OAR), we sought to describe infection episodes (IEp) resulting in hospitalization, in the early (<1 year) and late (≥1 year) post-transplant period and determine the impact of immunosuppression on incidence of infection.

METHODS

The primary aim was to assess the incidence and nature of IEp. The secondary aim was to evaluate the effect of potential risk factors, such as recipient age; sex; body mass index; panel-reactive antibodies; cytomegalovirus (CMV) primary mismatch; prednisone, tacrolimus, and sirolimus levels; and gene expression profile (GEP) score, in the development of IEp.

RESULTS

The OAR comprises 1,504 patients, of whom 220 patients (14.6%) had an IEp during a median follow-up period of 382 days (interquartile range [IQR] 230 to 579 days). The cause-specific 5-year hazard ratio for any infection was 2.029 (p = 0.12). The pattern of early infection was consistent with nosocomial and opportunistic causes, whereas later infection was consistent with late-onset opportunistic and community-acquired etiologies. Sixty-two percent of the infections occurred early. In the time-dependent analysis, higher prednisone dose (log prednisone, hazard ratio [HR] 1.30, p = 0.022) was the most significant risk factor for all IEp.

CONCLUSIONS

In the OAR cohort, the majority of infections occurred within 1 year after transplantation. Clinicians may consider more aggressive prednisone withdrawal in low-risk patients to reduce IEp.

Corticosteroid Weaning in Stable Heart Transplant Patients: Guidance by Serum Cortisol Level

Background

Despite earlier studies describing the feasibility of steroid weaning in heart transplant patients, the majority of patients are maintained on steroid therapy for life. We examined a strategy based on a single morning serum cortisol measurement.

Methods

We assigned stable posttransplant patients, who were maintained on tacrolimus, mycophenolate mofetil, and corticosteroids, into one of two groups based on a screening morning cortisol level. Patients with a cortisol < 8 micrograms/deciliter were assigned to a “maintenance” group and the others were assigned to the weaning group and steroids were tapered off over 4–6 weeks. Patients were monitored on subsequent office visits for adrenal insufficiency and allograft rejection.

Results

Thirty-one patients were enrolled (6 patients in the maintenance group and 25 in the steroid-weaning group). Mean follow-up was 10.2 ± 4 years for the weaning group and 9.0 ± 4.9 years in the maintenance group (p = 0.6). No cases of rejection were noted, nor did any patient resume steroid treatment following discontinuation.

Conclusion

Steroids can be safely discontinued in stable heart transplant patients with an AM serum cortisol ≥ 8 micrograms/deciliter with appropriate outpatient follow-up. In this study, no patient suffered late rejection or clinically noted adrenal insufficiency.

Cardiac transplantation in African Americans: a single-center experience

BACKGROUND

In view of limited data on the subject of graft and patient survival differences between African American (AA) and non-AA heart transplant recipients, we reviewed our experience.

HYPOTHESIS

There is a higher mortality among AA recipients compared with non-AA recipients after cardiac transplantation.

METHODS

The study included all AA patients who have received a heart transplant in our center since 1983. Stepwise Cox regression was used for covariates affecting the survival. The χ(2) test was employed to identify the effects of a mechanical assist device and pretransplant creatinine (Cr) on the outcomes in AA and non-AA patients. Kaplan-Meier curves were used to examine survival.

RESULTS

The average survival among AA recipients was 5.4 years, compared with 12 years for the non-AA recipients, with 1-, 5-, and 10-year survival rates of 80%, 55%, and 25%, respectively. This was found to be statistically inferior to the survival probabilities of 92%, 78%, and 58% for the non-AA group (P < 0.005). Based on stepwise Cox regression, the variables such as ethnicity (P < 0.05), pretransplant Cr (P < 0.05), presence of a mechanical assist device (P < 0.005), and United Network for Organ Sharing (UNOS) status at transplant (P < 0.05) independently predicted the outcomes. Kaplan-Meier analysis of pretransplant Cr level and survival showed that the AA group did significantly worse for all Cr classes.

CONCLUSIONS

There is a statistically significant difference in outcomes between AA and non-AA patients after cardiac transplantation. African American patients have decreased survival over a period of time. Pretransplant Cr, ethnicity, presence of a mechanical assist device, and UNOS status at transplantation are independent predictors of outcomes.

Nanoparticle PET-CT detects rejection and immunomodulation in cardiac allografts

BACKGROUND

Macrophages predominate among the inflammatory cells in rejecting allografts. These innate immune cells, in addition to allospecific T cells, can damage cardiomyocytes directly.

METHODS AND RESULTS

We explored whether sensitive positron emission tomography-computed tomography (PET-CT) imaging of macrophages-avid nanoparticles detects rejection of heart allografts in mice. In addition, we used the imaging method to follow the immunomodulatory impact of angiotensin-converting enzyme inhibitor therapy on myeloid cells in allografts. Dextran nanoparticles were derivatized with the PET isotope copper-64 and imaged 7 days after transplantation. C57BL/6 recipients of BALB/c allografts displayed robust positron emission tomography signal (standard uptake value allograft, 2.8±0.3; isograft control, 1.7±0.2; P<0.05). Autoradiography and scintillation counting confirmed the in vivo findings. We then imaged the effects of angiotensin-converting enzyme inhibitor (5 mg/kg enalapril). Angiotensin-converting enzyme inhibitor significantly decreased nanoparticle signal (P<0.05). Histology and flow cytometry showed a reduced number of myeloid cells in the graft, blood, and lymph nodes and diminished antigen presentation (P<0.05 versus untreated allografts). Angiotensin-converting enzyme inhibitor also significantly prolonged allograft survival (12 versus 7 days; P<0.0001).

CONCLUSIONS

Nanoparticle macrophage PET-CT detects heart transplant rejection and predicts organ survival by reporting on myeloid cells.

Steroid withdrawal and reduction of cyclosporine A under mycophenolate mofetil after heart transplantation

Survival and quality of life after heart transplantation are limited by a significant incidence of cardiovascular complications. Side effects of immunosuppressives contribute unfavorably. Aim of this study was to determine (1) whether withdrawal of corticosteroids and dose reduction of cyclosporine A can be performed safely under immunosuppressive therapy with mycophenolate mofetil and (2) if this is beneficial for renal function and cardiovascular risk reduction. Long term heart transplant recipients on steroids and cyclosporine A were examined in a monocentric, prospective, single-arm cohort study. Steroids were withdrawn, mycophenolate mofetil introduced and cyclosporine A dose reduced (target level 50-90 ng/ml). Follow up was 24 months. 23 patients were analyzed: Renal parameters (creatinine, urea, uric acid) improved significantly (p<0.01), as did cardiovascular parameters (heart rate [p<0.05], systolic and diastolic blood pressure [p<0.01]), HbA1c (p<0.05) and triglycerides (p<0.05). In contrast, the self-percepted state of health (SF36™) decreased. Drop outs occurred mostly due to steroid withdrawal syndrome [n=7]. The incidence of adverse events reflected the usual course after heart transplantation. We conclude that CS free immunosuppression comprising reduced cyclosporine levels and addition of MMF in long term heart transplant recipients is safe and improves the cardiovascular risk profile, carbohydrate metabolism and renal function.

Donor-recipient race mismatch and graft survival after pediatric heart transplantation

BACKGROUND

Black recipient race has been shown to predict poorer graft survival after pediatric heart transplantation. We analyzed our single-center experience comparing graft survival by race and the impact of donor-recipient race mismatch.

METHODS

One hundred sixty-nine consecutive primary pediatric heart transplant patients were analyzed by donor and recipient race (white recipient, 99; black recipient, 60; other, 10). The groups were similar in preoperative characteristics. There were fewer donor-recipient race matches in blacks compared with whites (10 versus 71; p < 0.0001).

RESULTS

Although 30-day and 6-month graft survival was similar for black and white recipients (93.9% and 85.8% versus 93.3% and 83.3%, respectively), overall actuarial graft survival was significantly lower in blacks (p < 0.019). Blacks tended to have a higher incidence of positive retrospective crossmatch (n = 26, 43%) than whites (n = 29, 29%), but this was not statistically significant (p = 0.053). The median graft survival for black recipients was 5.5 years compared with 11.6 years for whites. Donor-recipient race mismatch predicted poorer graft survival (5-year graft survival 48.9% versus 72.3%; p = 0.0032). The median graft survival for donor-recipient race-matched patients was more than twice that for mismatched patients (11.6 years versus 4.4 years). Cox proportional hazard analysis showed that donor-recipient race mismatch neutralized the effect of race on graft survival.

CONCLUSIONS

Graft survival after pediatric heart transplantation is inferior for black recipients compared with white recipients. These differences may be explained by a high incidence of donor-recipient race mismatch, which also predicts poorer outcome for all racial groups with pediatric heart transplantation. These data may have implications for future donor allocation schemes.