Early inpatient calculation of laboratory-based 30-day readmission risk scores empowers clinical risk modification during index hospitalization.

Improving 30-day readmission continues to be problematic for most hospitals. This study reports the creation and validation of sex-specific inpatient (i) heart failure (HF) risk scores using electronic data from the beginning of inpatient care for effective and efficient prediction of 30-day readmission risk. METHODS: HF patients hospitalized at Intermountain Healthcare from 2005 to 2012 (derivation: n=6079; validation: n=2663) and Baylor Scott & White Health (North Region) from 2005 to 2013 (validation: n=5162) were studied. Sex-specific iHF scores were derived to predict post-hospitalization 30-day readmission using common HF laboratory measures and age. Risk scores adding social, morbidity, and treatment factors were also evaluated. RESULTS: The iHF model for females utilized potassium, bicarbonate, blood urea nitrogen, red blood cell count, white blood cell count, and mean corpuscular hemoglobin concentration; for males, components were B-type natriuretic peptide, sodium, creatinine, hematocrit, red cell distribution width, and mean platelet volume. Among females, odds ratios (OR) were OR=1.99 for iHF tertile 3 vs. 1 (95% confidence interval [CI]=1.28, 3.08) for Intermountain validation (P-trend across tertiles=0.002) and OR=1.29 (CI=1.01, 1.66) for Baylor patients (P-trend=0.049). Among males, iHF had OR=1.95 (CI=1.33, 2.85) for tertile 3 vs. 1 in Intermountain (P-trend <0.001) and OR=2.03 (CI=1.52, 2.71) in Baylor (P-trend < 0.001). Expanded models using 182-183 variables had predictive abilities similar to iHF. CONCLUSIONS: Sex-specific laboratory-based electronic health record-delivered iHF risk scores effectively predicted 30-day readmission among HF patients. Efficient to calculate and deliver to clinicians, recent clinical implementation of iHF scores suggest they are useful and useable for more precise clinical HF treatment.

Reasons for, and outcomes of patients who were referred for a ventricular assist device but were declined: the recent era forgotten ones.

BACKGROUND: Ventricular assist devices (VADs) have a proven survival benefit in select patients with advanced heart failure, yet many patients considered for implantation are declined for various reasons. The outcome of these patients is obscure owing to their exclusion from recent VAD studies. We aim to compare the outcomes of patients who received a VAD to those who did not. METHODS: For this study, the Artificial Heart Program's database at Intermountain Medical Center was queried from 2006 to 2012 for patients referred for a VAD. Kaplan-Meier survival analysis was performed with log-rank test determining significance. RESULTS: Of 232 patients included, 118 patients received a VAD and 114 patients did not. The prevailing reason for VAD decline in eligible and willing patients was due to pre-existing illness (39%). Mortality was higher in non-VAD vs. VAD patients (58.8% vs. 35.6%, p < 0.001) with a median time-to-death of 67 (IQR:12-314) and 301 (IQR:136-694) d, respectively (p = 0.007). CONCLUSIONS: In the current era of non-pulsatile VADs, mortality of patients who are considered but not implanted remains high. Additionally, mortality of these patients occurred much sooner. Educational efforts ensuring timely referral for VAD therapy are important to maximize the number of patients who may benefit.

Interleukin receptor family member ST2 concentrations in patients following heart transplantation.

OBJECTIVE: To evaluate soluble (s) ST2 as a biomarker of rejection, allograft vasculopathy and mortality after orthotopic heart transplantation (OHT). METHODS: sST2 concentrations were measured in 241 patients following OHT. RESULTS: Elevated sST2 was associated with cellular rejection (CR) ≥ 1R, with highest rates of CR in the 4th sST2 quartile (p = 0.003). No significant association between sST2 and antibody-mediated rejection or allograft vasculopathy was found. sST2 ≥ 30 ng/mL independently predicted death over 7-year follow-up (HR = 2.01; 95% CI 1.15-3.51; p = 0.01). CONCLUSION: Concentrations of sST2 are associated with the presence of CR and predict long-term mortality following OHT.

Impact of high-dose inotropic donor support on early myocardial necrosis and outcomes in cardiac transplantation.

BACKGROUND: Cardiac donors routinely require vasoactive agents for circulatory stability after brain death. Nevertheless, inotropes have been associated with direct cardiac toxicity. Our study evaluated whether the use of high-dose inotropic support in potential donors was associated with increased early myocardial necrosis (MN) and worse clinical outcomes after cardiac transplantation. METHODS: The UTAH Cardiac Transplant Program (UCTP) and Intermountain Donor Services databases were queried for records between 1996 and 2009. The high-dose donor inotropic support (HDIS) group was defined as patients on dopamine >10 µg/kg/min. The incidence of early MN, intensive care unit (ICU) length of stay, length of ventilator support, and mortality was evaluated. RESULTS: Two hundred and forty-four recipients undergoing transplant met study criteria. The average donor age was 27 yr. The incidence of MN in the HDIS (n=29) and non-HDIS (n=204) groups was 14.8% and 6.7%, respectively, OR 2.67. Total ischemic time, ventilator support time, ICU stay, and actuarial survival were similar between both groups. CONCLUSION: The use of high-dose inotropic support to maintain donor stability appears to have a higher trend for early post-transplant MN without an impact on clinical outcomes. With the current growing shortage of organ donors, it appears reasonable to use donors on high-dose inotropic support.

Differential impact on post-transplant outcomes between pulsatile- and continuous-flow left ventricular assist devices.

BACKGROUND: The HeartMate II (HMII) left ventricular assist device (LVAD) has proven reliable and durable and has become the preferred choice for bridge to transplant therapy (BTT) when compared with the pulsatile HeartMate XVE (XVE). In this study, we compared the post-transplant (PTx) outcomes between XVE and HMII using a large national data registry. METHODS: The Organ Procurement and Transplantation Network (OPTN)/United Network for Organ Sharing (UNOS) Thoracic Registry database was queried for all patients implanted with either an XVE or an HMII as BTT during 2004-2009. Statistical analysis between XVE and HMII were performed using Kaplan-Meier survival analysis and Cox regression analyses. RESULTS: A total of 673 patients were implanted with the XVE and 484 with HMII. When adjusted for age, gender, ethnicity, intra-aortic balloon pump, ventilator, inotropes, dialysis, body mass index, creatinine, bilirubin, transfusion, pulmonary capillary wedge, and pulmonary arterial pressures, the HMII had similar one- and three-yr survival (hazard ratio = 0.95, CI = 0.64, 1.42) and rejection-free survival PTx compared to XVE. The XVE group had more early incidences of allograft rejection (AR) and hospitalization for infection (HI). CONCLUSIONS: Compared to XVE, patients with HMII have similar one- and three-yr survival after heart transplantation with less risk of early graft rejection and significant infection. With a strong shift toward use of continuous-flow LVADs, PTx outcomes are expected to continue to improve.

Automated identification and predictive tools to help identify high-risk heart failure patients: pilot evaluation.

OBJECTIVE: Develop and evaluate an automated identification and predictive risk report for hospitalized heart failure (HF) patients. METHODS: Dictated free-text reports from the previous 24 h were analyzed each day with natural language processing (NLP), to help improve the early identification of hospitalized patients with HF. A second application that uses an Intermountain Healthcare-developed predictive score to determine each HF patient's risk for 30-day hospital readmission and 30-day mortality was also developed. That information was included in an identification and predictive risk report, which was evaluated at a 354-bed hospital that treats high-risk HF patients. RESULTS: The addition of NLP-identified HF patients increased the identification score's sensitivity from 82.6% to 95.3% and its specificity from 82.7% to 97.5%, and the model's positive predictive value is 97.45%. Daily multidisciplinary discharge planning meetings are now based on the information provided by the HF identification and predictive report, and clinician's review of potential HF admissions takes less time compared to the previously used manual methodology (10 vs 40 min). An evaluation of the use of the HF predictive report identified a significant reduction in 30-day mortality and a significant increase in patient discharges to home care instead of to a specialized nursing facility. CONCLUSIONS: Using clinical decision support to help identify HF patients and automatically calculating their 30-day all-cause readmission and 30-day mortality risks, coupled with a multidisciplinary care process pathway, was found to be an effective process to improve HF patient identification, significantly reduce 30-day mortality, and significantly increase patient discharges to home care.

ISHLT pathology antibody mediated rejection score correlates with increased risk of cardiovascular mortality: A retrospective validation analysis.

BACKGROUND: Antibody-mediated rejection (AMR) in cardiac transplant recipients is a serious form of rejection with adverse patient outcomes. The International Society of Heart and Lung Transplantation (ISHLT) has published a consensus schema for the pathologic diagnosis of various grades of antibody-mediated rejection (pathology antibody-mediated rejection [pAMR]). We sought to determine whether the ISHLT pAMR grading schema correlates with patient outcomes. METHODS: Using our database, which contains a semi-quantitative scoring of all pathologic descriptors of pAMR, we retrospectively used these descriptors to convert the previous AMR categories to the current ISHLT pAMR categories. Cox proportional hazard models were fit with cardiovascular (CV) death or retransplant as the outcome. The pAMR value was included as a categorical variable, and cellular rejection (CR) values were included in a separate model. RESULTS: There were 13,812 biopsies from 1,014 patients analyzed. The pAMR grades of pAMR1h, pAMR1i, and pAMR2 conferred comparable increased risk for CV mortality. Significantly increased risk of CV mortality was conferred by biopsies graded as severe AMR (pAMR3). CONCLUSIONS: The new ISHLT pAMR grading schema identifies patients at increased risk of CV mortality, consistent with risks published from several programs before 2011. The current schema is validated by this analysis in a large biopsy database. Because pAMR1h, pAMR1i, and pAMR2 have similar CV risks associated with them, the threshold for a positive diagnosis of pAMR should be re-evaluated in future iterations of the ISHLT schema.

Mixed cellular and antibody-mediated rejection in heart transplantation: In-depth pathologic and clinical observations.

BACKGROUND: Little is known about mixed cellular and antibody-mediated rejection (MR) in heart transplantation. It remains unclear whether cardiac MR has distinctive pathologic and clinical features beyond those of simultaneous cellular rejection (CR) and antibody-mediated rejection (AMR). In this study we systematically explore the pathologic and clinical characteristics of MR in heart transplantation. METHODS: The UTAH Cardiac Transplant Program database was queried for transplant recipients who survived long enough to have at least one endomyocardial biopsy (EMB) between 1985 and 2014. Only EMBs with both CR and AMR scores documented were included. In addition to detailed pathologic analyses, we also examined the incidence and prevalence of MR, the likelihood to transition from and to MR, and mortality associated with MR. RESULTS: Patients (n = 1,207) with a total of 28,484 EMBs met the study inclusion criteria. The overall prevalence of MR was 7.8% and it was nearly twice as frequent within the first year post-transplant. Mild MR was by far the most common occurrence and was typically preceded by an immune active state. When CR increased in severity, AMR tended to follow, but the reverse was not true. On pathology, individual features of CR and AMR were more easily separated in cases of mild MR, whereas they substantially overlapped in more severe cases. MR was associated with a significant cardiovascular death risk that was incremental with severity. CONCLUSIONS: MR is not common, usually occurs early after transplant, and is associated with worse outcomes. MR reflects a complex interplay between cellular and humoral processes, which varies with rejection severity.

Impact of Ischemic Heart Failure Etiology on Cardiac Recovery During Mechanical Unloading.

BACKGROUND: Small-scale studies focused mainly on nonischemic cardiomyopathy (NICM) have shown that a subset of left ventricular assist device (LVAD) patients can achieve significant improvement of their native heart function, but the impact of ischemic cardiomyopathy (ICM) has not been specifically investigated. Many patients with acute myocardial infarction are discharged from their index hospitalization without heart failure (HF), only to return much later with overt HF syndrome, mainly caused by chronic remodeling of the noninfarcted region of the myocardium. OBJECTIVES: This study sought to prospectively investigate the effect of ICM HF etiology on LVAD-associated improvement of cardiac structure and function using NICM as control. METHODS: Consecutive patients (n = 154) with documented chronic and dilated cardiomyopathy (ICM, n = 61; NICM, n = 93) requiring durable support with continuous-flow LVAD were prospectively evaluated with serial echocardiograms and right heart catheterizations. RESULTS: In patients supported with LVAD for at least 6 months, we found that 5% of subjects with ICM and 21% of subjects with NICM achieved left ventricular ejection fraction ≥40% (p = 0.034). LV end-diastolic and end-systolic volumes and diastolic function were significantly and similarly improved in patients with ICM and NICM. CONCLUSIONS: LVAD-associated unloading for 6 months resulted in a substantial improvement in myocardial structure, and systolic and diastolic function in 1 in 20 ICM and 1 in 5 NICM patients. These specific incidence and timeline findings may provide guidance in clinical practice and research design for sequencing and prioritizing advanced HF and heart transplantation therapeutic options in patients with ICM and NICM.

Lactic acidosis after cardiac transplantation: foe or common innocent bystander?

BACKGROUND: Lactic acidosis (LA) frequently occurs after heart transplantation (HTx). It is hypothesized to be related to inotropic support or metabolic derangements from chronic heart failure. As such, restoring hemodynamic stability with mechanical circulatory support before HTx should mitigate this problem. Our aim was to evaluate the incidence and outcomes of LA after HTx. METHODS: We evaluated HTx recipients January 2000 to May 2011. Post-HTx outcomes included graft dysfunction, length of intensive care unit stay, length of hospital stay, inotropic support, and survival. RESULTS: Of 143 eligible patients, 98.6% had LA, 67% severe, after HTx. Data were analyzed based on the severity of LA. Time to peak lactate, intensive care unit stay, length of hospital stay, peak glucose, inotropic dose, graft dysfunction, and survival after HTx were similar between groups. Statistically significant differences included pretransplant support (25.6% mechanical circulatory support in nonsevere vs. 44.9% severe LA), hospitalization at the time of HTx (37.2% vs. 21.4%), glucose at the time of peak lactate (182.88 ± 69.80 vs. 221.31 ± 56.91), ischemic time (187.4 ± 63.1 vs. 215.5 ± 68.1), and duration of inotrope. CONCLUSION: Severe LA is common after HTx, though it appears to be transient and benign. Mechanical circulatory support after HTx does not prevent LA. High lactate levels are associated with longer ischemic times, longer duration of inotrope, and correspond with higher glucose levels. The underlying mechanism is yet to be satisfactorily elucidated.

Comparing velour versus silicone interfaces at the driveline exit site of HeartMate II devices: infection rates, histopathology, and ultrastructural aspects.

BACKGROUND: Driveline exit site (DLES) infection is a major complication of ventricular assist devices (VADs). Differences in the sheath material interfacing with exit site tissue appear to affect healing time and infection risk more than site hygiene, but the mechanistic basis for this is not clear. METHODS: Health record data from Utah Artificial Heart Program patients with HeartMate II (HMII) devices implanted from 2008 to 2012 were retrospectively reviewed, with particular attention to interface type, incorporation (healing) time, and infections. Tissue samples from the DLES were collected at the time of VAD removal in a small subset. These samples were examined by routine histology and environmental scanning electron microscopy (ESEM). RESULTS: Among 57 patients with sufficient data, 15 had velour interfaces and 42 had silicone. Indications for and duration of support were similar between the groups. The silicone group had shorter incorporation time (45 ±22 vs. 56 ±34 days, P=.17) and fewer DLES infections (20% vs. 1.7%, P=.026, for patient infections and 0.0340 vs. 0.166, P=.16, for infections per patient-year). Tissues from five patients, three with velour, were examined. Velour interfaces demonstrated more hyperkeratosis, hypergranulosis, and dermal inflammation. By ESEM, the silicone driveline tracts appeared relatively smooth and flat, whereas the velour interface samples were irregular with deep fissures and globular material adhering to the surface. CONCLUSIONS: Using the silicone portion of the HMII driveline at the DLES was associated with fewer infections and a trend toward faster healing in this small retrospective series. Whether the intriguing microscopic differences directly account for this needs further study on a larger scale.

Coronary computed tomography angiography for the detection of cardiac allograft vasculopathy: a meta-analysis of prospective trials.

OBJECTIVES: This study aimed to evaluate the diagnostic accuracy of coronary computed tomography angiography (CCTA) for detecting cardiac allograft vasculopathy (CAV) in comparison with conventional coronary angiography (CCAG) alone or with intravascular ultrasound (IVUS). BACKGROUND: CAV limits long-term survival after heart transplantation, and screening for CAV is performed on annual basis. CCTA is currently not recommended for CAV screening due to the limited accuracy reported by early studies. Technological advances, however, might have resulted in improved test performance and might justify re-evaluation of this recommendation. METHODS: A systematic review of Medline, Cochrane, and Embase for all prospective trials assessing CAV using CCTA was performed using a standard approach for meta-analysis for diagnostic test and a bivariate analysis. RESULTS: Thirteen studies evaluating 615 patients (mean age 52 years, 83% male) and 9,481 segments fulfilled inclusion criteria. Patient-based analyses comparing CCTA versus CCAG for the detection of any CAV (> luminal irregularities) and significant CAV (stenosis ≥50%), showed mean weighted sensitivities of 97% and 94%, specificities of 81% and 92%, a negative predictive value (NPV) of 97% and 99%, a positive predictive value (PPV) of 78% and 67%, and diagnostic accuracies of 88% and 94%, respectively. There was a strong trend toward improved sensitivity (97% vs. 91%, p = 0.06) and NPV (99% vs. 97%, p = 0.06) to detect significant CAV with 64-slice compared with 16-slice CCTA. A patient-based analysis of 64-slice CCTA versus IVUS showed a mean weighted sensitivity and specificity of 81% and 75% to detect CAV (intimal thickening >0.5 mm), whereas the PPV and NPV were 93% and 50%, respectively. CONCLUSIONS: CCTA using currently available technology is a reliable noninvasive imaging alternative to coronary angiography with an excellent sensitivity, specificity, and NPV for the detection of CAV.

Electromagnetic interference of automatic implantable cardioverter defibrillator and HeartWare left ventricular assist device.

The use of continuous-flow left ventricular assist devices (LVAD) have markedly improved outcomes in patients with advanced heart failure (HF). The HeartWare LVAD is a miniaturized centrifugal pump implanted within the pericardial space. Implantable cardioverter-defibrillators (ICDs) are susceptible to oversensing of extracardiac signals (electromagnetic interference [EMI]). We report two cases of EMI in patients that received a HeartWare LVAD as destination therapy for advanced HF. The patients were 75 and 78 years old, both with severe ischemic dilated cardiomyopathy (ejection fraction < 0.20) and New York Heart Association class 4 heart failure. Both patients had a St. Jude Medical Unify ICD with a 7 Fr dual coil St. Jude Medical Durata ICD lead. In both patients, the lead location was in the right ventricular apex with an inferior orientation. Both patients experienced immediate ICD therapies after LVAD placement, requiring the tachytherapies to be disabled. ICD programming changes to increase sensitivity and the detection windows were ineffective. Both patients underwent ICD system revision. In one patient, the existing lead was moved to an anteroseptal location that stopped the EMI. In the other patient, the ICD system was changed to allow a separate right ventricular sensing lead in an anteroseptal location and a dual coil ICD lead placed in an apical location, a strategy used to obtain an acceptable defibrillation threshold. The patients have had no subsequent EMI detected on clinical and remote monitoring. Patients with a right ventricular apical ICD lead placement that undergo placement of a HeartWare LVAD are susceptible to EMI and inappropriate ICD therapies. These cases suggest the primary mechanism is proximity of the ICD lead to the device and as such relocation to an anteroseptal location can overcome the problem. These data suggest that all patients that receive a HeartWare LVAD with an ICD should have the device carefully checked at maximum LVAD output to determine if EMI may be present. ASAIO Journal 2013;59:136-139. Key Words: left ventricular assist device, electromagnetic interference, improper ICD shocks, end-stage heart failure.

Repeated measurement of the intermountain risk score enhances prognostication for mortality.

BACKGROUND: The Intermountain Risk Score (IMRS), composed of the complete blood count (CBC) and basic metabolic profile (BMP), predicts mortality and morbidity in medical and general populations. Whether longitudinal repeated measurement of IMRS is useful for prognostication is an important question for its clinical applicability. METHODS: Females (N = 5,698) and males (N = 5,437) with CBC and BMP panels measured 6 months to 2.0 years apart (mean 1.0 year) had baseline and follow-up IMRS computed. Survival analysis during 4.0±2.5 years (maximum 10 years) evaluated mortality (females: n = 1,255 deaths; males: n = 1,164 deaths) and incident major events (myocardial infarction, heart failure [HF], and stroke). RESULTS: Both baseline and follow-up IMRS (categorized as high-risk vs. low-risk) were independently associated with mortality (all p<0.001) in bivariable models. For females, follow-up IMRS had hazard ratio (HR) = 5.23 (95% confidence interval [CI] = 4.11, 6.64) and baseline IMRS had HR = 3.66 (CI = 2.94, 4.55). Among males, follow-up IMRS had HR = 4.28 (CI = 3.51, 5.22) and baseline IMRS had HR = 2.32 (CI = 1.91, 2.82). IMRS components such as RDW, measured at both time points, also predicted mortality. Baseline and follow-up IMRS strongly predicted incident HF in both genders. CONCLUSIONS: Repeated measurement of IMRS at baseline and at about one year of follow-up were independently prognostic for mortality and incident HF among initially hospitalized patients. RDW and other CBC and BMP values were also predictive of outcomes. Further research should evaluate the utility of IMRS as a tool for clinical risk adjustment.

Peripartum cardiomyopathy: post-transplant outcomes from the United Network for Organ Sharing Database.

BACKGROUND: Nearly 25% of patients with peripartum cardiomyopathy (PPCM) will require cardiac transplantation. Whether post-transplant outcomes differ among patients with PPCM compared with other recipients remains unsettled. METHODS: The United Network for Organ Sharing database was queried for cardiac transplants, comparing characteristics and outcomes for PPCM, other women, and all others. RESULTS: Between 1987 and 2010, 42,406 patients (9,419 women and 32,987 men) received a heart transplant. Of these, 485 women who had PPCM as the indication were younger (p < 0.001), had higher sensitization (p < 0.001), required higher intensity of cardiovascular support pre-transplant (p = 0.026), and had higher listing status (p < 0.001). Those with PPCM had more post-transplant rejection during the index transplant hospitalization (p < 0.001) and during the first year (p = 0.003). Comparing PPCM with other women and all others, graft survival was inferior (p = 0.004 and p < 0.003, respectively) and age-adjusted survival was lower (p < 0.001 and p = 0.02, respectively). CONCLUSIONS: This large report shows outcomes of graft failure and death are inferior for recipients with PPCM, which may be partly explained by younger age, higher allosensitization, higher pre-transplant acuity, and increased rejection. More research is needed to determine management strategies to improve outcomes in PPCM heart transplant recipients.

Longitudinal evaluation of microvessel density in survivors vs. nonsurvivors of cardiac pathologic antibody-mediated rejection.

BACKGROUND: Antibody-mediated rejection (AMR) of cardiac allografts is associated with reduced long-term graft survival, but not every patient with AMR develops premature graft failure. The tissue level mechanisms leading to graft failure in some patients with antibody-mediated rejection are poorly characterized. METHODS: We assessed changes in myocardial microvessel density (number of capillaries per unit area) in endomyocardial biopsies over time using whole-slide microscopic imaging of CD34-stained slides and computer-assisted image analysis. Changes were compared among eight heart transplant recipients with multiple episodes of pathologic AMR who died from cardiovascular causes, eight age- and gender-matched patients with pathologic AMR who were still alive at a similar follow-up interval, and six matched controls without AMR or cellular rejection. RESULTS: Microvessel density decreased in the last biopsies (mean 6.52 years post-transplant) from patients with pathologic AMR and cardiovascular mortality compared to their biopsies at 6 and 12 months post-transplant [respectively, -22% (P=.02) and -25% (P=.02)]. A similar decrease was not seen for the other groups. CONCLUSIONS: Significantly reduced myocardial microvessel density does occur in a subset of patients with pathologic AMR who have a worse outcome. These data provide insights into the interplay between AMR, microvascular injury, and clinical outcomes.

Biopsy-diagnosed antibody-mediated rejection based on the proposed International Society for Heart and Lung Transplantation working formulation is associated with adverse cardiovascular outcomes after pediatric heart transplant.

BACKGROUND: There is greater awareness of the pathologic features and clinical implications of antibody-mediated rejection (AMR) after heart transplantation (HT). Yet, compared with adults, the lack of routine surveillance for AMR has limited the growth of evidence in the pediatric population. Herein, we compared outcomes of pediatric HT recipients with and without AMR. METHODS: All recipients ≤18 years of age with at least 1 endomyocardial biopsy (EMB) between 1988 and 2009 were included in this study. Assessment for AMR was routine. AMR severity was assigned retrospectively using the proposed 2011 ISHLT grading schema for pathologic AMR (pAMR). Outcome comparisons were made between patients with histologic and immunopathologic evidence for AMR (pAMR 2), those with severe AMR (pAMR 3), and those without evidence of AMR (pAMR 0) or without both histologic and immunopathologic findings (pAMR 1). RESULTS: Among 1,406 EMBs, pAMR 2 or higher was present in 258 (18%), occurring in 45 of 76 (59%) patients. Of the 17 episodes of pAMR 3 in 9 patients, 6 (35%) were sub-clinical. Mortality was not different between groups. Patients with at least 1 pAMR 3 episode had lower freedom from cardiovascular (CV) mortality or cardiac allograft vasculopathy within 5 years of HT than those without pAMR 3 (45% vs 91%, p < 0.001). CONCLUSIONS: Biopsy findings of AMR (pAMR 2 or higher) are common after pediatric HT. Like cellular rejection, biopsy grading of AMR seems important to delineate those at risk of adverse events. Our results suggest that pAMR 3 is associated with worse CV outcomes. Widespread surveillance for pAMR with a uniform grading system is an important next step to further validate these findings in the pediatric HT population.

A longitudinal study of the course of asymptomatic antibody-mediated rejection in heart transplantation.

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.

Would access to device therapies improve transplant outcomes for adults with congenital heart disease? Analysis of the United Network for Organ Sharing (UNOS).

BACKGROUND: Patients with congenital heart disease (CHD) now survive into adulthood and often present with end-stage heart failure (HF). HF management and approach to orthotopic heart transplant (OHT) may differ from adults without CHD. We sought to compare OHT waitlist characteristics and outcomes for these 2 groups. METHODS: The Organ Procurement and Transplantation Network (OPTN)/United Network for Organ Sharing (UNOS) database was used to identify adults (≥18 years) listed for OHT from 2005 to 2009. The cohort was divided into those with or without CHD. RESULTS: Of 9,722 adults included, 314 (3%) had CHD. Adults with CHD were younger (35 ± 13 vs 52 ± 12 years, p < 0.01) and more often had undergone prior cardiac surgery (85% vs. 34%, p < 0.01). Patients with CHD were less likely to have a defibrillator (44% vs 75%, p < 0.01) or ventricular assist device (5% vs 14%, p < 0.01) and were more likely to be listed at the lowest urgency status than patients without CHD (64% vs 44%, p < 0.01). Fewer CHD patients achieved OHT (53% vs 65%, p < 0.001). Although overall waitlist mortality did not differ between groups (10% vs 8%, p = 0.15), patients with CHD were more likely to experience cardiovascular death (60% vs 40%, p = 0.03), including sudden in 44% and due to HF in 16%. CONCLUSIONS: Despite lower urgency status, patients with CHD have greater cardiovascular mortality awaiting OHT than those without. Increased defibrillator use could improve survival to OHT, because sudden death is common. VAD support may benefit select patients, but experience in CHD is limited. Referral to specialized adult congenital heart centers can enhance utilization of device therapies and potentially improve waitlist outcomes.

Antibody testing for cardiac antibody-mediated rejection: which panel correlates best with cardiovascular death?

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.