Tolerability of sirolimus: a decade of experience at a single cardiac transplant center.

Sirolimus is used in cardiac transplant recipients to prevent rejection, progression of cardiac allograft vasculopathy, and renal dysfunction. However, sirolimus has many potential side effects and its tolerability when used outside of clinical trials is not well established. We describe a decade of experience with sirolimus in cardiac transplant recipients at our institution. We retrospectively reviewed records of all adult cardiac transplant recipients living between September 1999 and February 2010 (n = 329) and identified 67 patients (20%) who received sirolimus. The indications for sirolimus were cardiac allograft vasculopathy (67%), renal dysfunction (25%), rejection (4%), and intolerability of tacrolimus (3%). One-third of patients discontinued sirolimus at a median (25th, 75th percentiles) of 0.9 (0.2, 1.6) yr of duration. Over 70% of subjects experienced an adverse event attributed to sirolimus. Adverse events were associated with higher average sirolimus levels (9.1 ng/mL vs. 7.1 ng/mL, p = 0.004). We conclude that sirolimus is frequently used in cardiac transplant recipients (20%) and commonly causes side effects, often necessitating discontinuation. Higher average sirolimus levels were associated with adverse events, suggesting that tolerability may improve if levels are maintained within the lower end of the current therapeutic range; however, the improvement in tolerability would need to be balanced with the potential for decreased efficacy.

Sirolimus use and incidence of venous thromboembolism in cardiac transplant recipients.

Sirolimus is an immunosuppressive agent increasingly used in cardiac transplant recipients in the setting of allograft vasculopathy or worsening renal function. Recently, sirolimus has been associated with increased risk of venous thromboembolism (VTE) in lung transplant recipients. To investigate whether this association is also present in cardiac transplant recipients, we retrospectively reviewed the charts of 67 cardiac transplant recipients whose immunosuppressive regimen included sirolimus and 134 matched cardiac transplant recipients whose regimen did not include sirolimus. Rates of VTE were compared. Multivariable Cox proportional hazards models tested the association of sirolimus use with VTE. A higher incidence of VTE was seen in patients treated with vs. without sirolimus (8/67 [12%] vs. 9/134 [7%], log-rank statistic: 4.66, p=0.03). Lower body mass index (BMI) and total cholesterol levels were also associated with VTE (p<0.05). The association of sirolimus with VTE persisted when adjusting for BMI (hazard ratio [95% confidence interval]: 2.96 [1.13, 7.75], p=0.03) but not when adjusting for total cholesterol (p=0.08). These data suggest that sirolimus is associated with an increased risk of VTE in cardiac transplant recipients, a risk possibly mediated through comorbid conditions. Larger, more conclusive studies are needed. Until such studies are completed, a heightened level of awareness for VTE in cardiac transplant recipients treated with sirolimus appears warranted.

Bridge to heart transplantation with left ventricular assist device versus inotropic agents in status 1 patients.

OBJECTIVE: Left ventricular assist devices (LVADs) are commonly used for critically ill patients awaiting heart transplantation, although their effect on long-term outcomes, relative to inotropic support alone, is still debated. METHOD: Data from Status 1 patients who underwent heart transplantation at our institution between 1990 and 2005 were reviewed (n = 180). They were divided into two groups: those who underwent LVAD implantation as a bridge to transplant (n = 31) and those treated with inotropic agents without the support of LVAD (n = 149). They were compared in terms of demographics and clinical outcome. RESULTS: Both groups were similar in terms of patient and donor demographics. Relative to the inotrope group, the LVAD group did have a longer ischemic time (p = 0.032), a greater incidence of pretransplant transfusion (p < 0.00001), and a greater maximum level of pretransplant panel reactive antibodies (p < 0.001). Creatinine at listing significantly improved in LVAD patients awaiting transplantation (p < 0.0001). Comparisons of 5-year survival in addition to freedom from posttransplant infection, malignancy, revascularization, and acute rejection did not show significant difference between the two groups. The LVAD group did benefit from increased freedom from chronic rejection compared to the inotrope group (p = 0.049). Stepwise Cox Regression did not identify any independent factors affecting patient survival during the first 5 years after transplant. CONCLUSIONS: Status 1 patients successfully bridged to heart transplantation with LVADs had similar long-term clinical outcomes compared to those treated with inotropic agents.

Low voltage on the electrocardiogram is a marker of disease severity and a risk factor for adverse outcomes in patients with heart failure due to systolic dysfunction.

BACKGROUND: The prognostic implications of low QRS voltage on the electrocardiogram (ECG) in heart failure (HF) are not well characterized. METHODS: We manually measured and summed the QRS voltage in all 12 leads of the ECG (sumQRS) in two cohorts: (1) 415 patients with a low left ventricular ejection fraction followed up in a HF clinic ("clinic cohort") and (2) 100 subjects with advanced HF who had an ECG within 1 year preceding cardiac transplantation ("pretransplant cohort"). Low voltage was defined as the lowest quartile of the clinic cohort (sumQRS <12 mV) and its prevalence was compared in the two cohorts. The associations of low voltage with 1-year outcomes were assessed in the clinic cohort. RESULTS: In the clinic cohort, the frequency of low voltage was higher in New York Heart Association class 4 versus class 1-3 patients (34% vs 22% respectively, P = .04). The frequency of low voltage in the pretransplant cohort (47%) was twice that of the clinic cohort (24%, P < .001). After 1 year of follow-up in the clinic cohort, low ECG voltage was associated with a higher rate of death (14% vs 5%, P = .008) and the composite end point of death or HF hospitalization (35% vs 20%, P = .004). These associations persisted in multivariable analyses adjusting for important confounders. CONCLUSIONS: Low ECG voltage is a marker of the severity of HF and is a risk factor for adverse outcomes in patients with systolic HF at 1 year.

Predictors of pericardial effusion after orthotopic heart transplantation.

OBJECTIVES: Pericardial effusion occurs frequently after orthotopic heart transplantation, but the causes of this complication have not been well described. This study was designed to identify factors predisposing toward the development of significant postoperative pericardial effusions in a large, single-institution population of orthotopic heart transplant recipients. METHODS: A retrospective review of more than 90 preoperative, intraoperative, and postoperative variables was conducted for 241 patients undergoing orthotopic heart transplantation from September 1988 to December 1999. Patients who had significant postoperative pericardial effusions develop were identified from postoperative echocardiograms by standard criteria. Factors associated with the development of significant pericardial effusions were determined by multivariate logistic regression analysis. RESULTS: Echocardiographic data were available for 203 of 241 transplant recipients. Forty-two patients (21%) had significant effusions develop. According to multivariate analysis, pericardial effusions were less likely to occur in recipients with a history of previous cardiac surgery (odds ratio 0.13, 95% confidence interval 0.05-0.36, P <.0001) and with greater weight (odds ratio 0.96, 95% confidence interval 0.94-0.99, P <.0048). Pericardial effusions were more likely to occur in patients who had received aminocaproic acid during the operation (odds ratio 5.92, 95% confidence interval 2.23-15.72, P <.0008). Patient survival and hospital length of stay did not differ between patients with and without postoperative pericardial effusions. CONCLUSIONS: Postoperative pericardial effusions develop in approximately 20% of patients undergoing orthotopic cardiac transplantation. On the basis of the risk factors identified in this study, prevention may prove difficult, although avoidance of the intraoperative use of aminocaproic acid may be helpful.

Relationship of right- and left-sided filling pressures in patients with advanced heart failure: a 14-year multi-institutional analysis.

BACKGROUND: Jugular venous pressure (JVP) is assessed to estimate volume status in patients with heart failure because right atrial pressure (RAP) reflects pulmonary capillary wedge pressure (PCWP). In a large cohort of heart failure patients spanning 14 years, we sought to further characterize the relationship between RAP and PCWP, including identifying temporal trends, to optimize estimates of PCWP by JVP. We also sought to determine whether the RAP to PCWP relationship impacts post-transplant mortality. METHODS: Hemodynamic data were obtained from 4,079 patients before cardiac transplantation. Elevated RAP was defined as ≥10 mm Hg and elevated PCWP ≥22 mm Hg. Hemodynamics were "concordant" when both RAP and PCWP were elevated or when both were not elevated. The frequency of concordant hemodynamics was assessed over 3 eras (1993 to 1997, 1998 to 2002, 2003 to 2007). Baseline characteristics were compared among quartiles of the ratio (RAP+1)/PCWP. The association of (RAP+1)/PCWP with 2-year mortality after cardiac transplantation was assessed using multivariate models. RESULTS: The frequency of concordant hemodynamics over time was stable (74%, 72%, 73%; p = 0.4). Increasing (RAP+1)/PCWP was associated with the following variables: female gender; cardiomyopathy etiology besides ischemic or non-ischemic; prior sternotomies; and lower creatinine clearance (p < 0.01 for all). Elevated (RAP+1)/PCWP was associated with post-transplant mortality (relative risk 1.2, 95% confidence interval 1.02 to 1.37, p = 0.02). CONCLUSIONS: [corrected] RAP and PCWP remain concordant in most heart failure patients, supporting the ongoing use of JVP to estimate PCWP. Easily identifiable patient characteristics were associated with an increased RAP/PCWP ratio, and their presence should alert clinicians that PCWP may be overestimated by JVP assessment. A higher RAP/PCWP ratio was an adverse risk factor for post-cardiac transplant survival.

Concentric left ventricular hypertrophy as assessed by cardiac magnetic resonance imaging and risk of death in cardiac transplant recipients.

BACKGROUND: Although risk factors for left ventricular (LV) hypertrophy in the native heart are well known, as is its association with increased risk of adverse outcomes, such information is poorly defined in heart transplant (HTx) recipients. We determined whether increased LV mass and concentricity (mass/volume) were associated with death in patients after HTx. METHODS: Between May 2003 and May 2006, 140 HTx recipients underwent cardiac magnetic resonance imaging (MRI). Clinical characteristics associated with increased LV mass were determined. Cox proportional hazard models were constructed to assess the relationship of LV mass and concentricity with death. RESULTS: MRIs were acquired a median of 6.0 years after transplant. The top quartile of indexed LV mass and concentricity were 35.8 g/m(2.7) or higher and 1.5 g/ml or higher, respectively. History of rejection (odds ratio [OR], 5.9; 95% confidence interval [CI], 2.1-16.4; p < 0.01), diabetes (OR, 3.3; 95% CI, 1.3-8.2; p = 0.01), and post-transplant year of MRI acquisition (OR, 1.2; 95% CI, 1.1-1.4; p < 0.01) were associated with the top quartile of LV mass in multivariable models. LV mass and concentricity were independently associated with cardiovascular death (hazard risk [HR], 1.11 per g/m;(2.7) HR, 10.1 per g/ml, p ≤ 0.01, respectively). LV concentricity was independently associated with all-cause mortality (HR, 4.4 per g/ml, p < 0.01). CONCLUSION: A history of rejection and diabetes are associated with increased LV mass. Increased LV mass, particularly of a concentric phenotype, is an independent risk factor for cardiovascular and all-cause mortality after HTx.

Utility of routine immunofluorescence staining for C4d in cardiac transplant recipients.

BACKGROUND: Immunofluorescence staining of endomyocardial biopsy (EMB) specimens to detect the complement fragment C4d is used to diagnose antibody-mediated rejection. However, data are limited regarding the utility of routine staining for C4d in clinical care. METHODS: This study retrospectively reviewed the clinical course of adult cardiac transplant recipients who underwent > or = 2 EMBs with immunofluorescence C4d staining at the University of Texas Southwestern Medical Center since September 2006. C4d staining was performed by the immunohistochemistry laboratory and interpreted by the members of the surgical pathology department, in conjunction with interpretation of the routine hematoxylin and eosin staining. Donor-specific antibodies (DSA) were routinely assessed at the time of clinical rejection. RESULTS: Of 67 patients, specimens were positive for C4d (C4d+) in 14 and negative for C4d (C4d-) in 53. The frequency of acute cellular rejection (ACR) in these 2 groups was 57% (8 of 14, designated C4d+/ACR+) vs 11% (6 of 53, designated C4d-/ACR+; p < 0.001). Significantly more patients with a positive C4d specimen had a positive retrospective donor specific crossmatch, presence of DSA after transplantation, and depressed graft function (p < 0.01 for each). CONCLUSIONS: Positive C4d immunofluorescence staining on EMB specimens was associated with ACR, reduced allograft function, a positive retrospective crossmatch, and the presence of DSA after transplantation. The latter 2 observations support the contention that C4d deposition is a marker of antibody-mediated rejection. Routine evaluation of C4d staining is feasible in the clinical setting and may identify variable patterns of rejection.

Utility of the Cylex assay in cardiac transplant recipients.

BACKGROUND: Although the Cylex immune assay has been proposed as a means of tailoring immunosuppression after organ transplantation, there are limited data regarding its utility in cardiac transplant recipients. Therefore, we sought to determine the utility of the Cylex assay in assessing the risk of infection or rejection in cardiac transplant recipients. METHODS: This study is a retrospective review of the clinical course of all adult cardiac transplant recipients who underwent a Cylex assay at UT Southwestern Medical Center between January 2004 and September 2007. RESULTS: One hundred eleven patients were free of significant rejection or infection at the time of the first Cylex assay. Most patients (92%) were >1 year post-transplant. Over the next 157 +/- 41 (mean +/- SD) days, 2 patients had 3 episodes of rejection requiring therapy and 7 patients had 8 infections requiring therapy. The Cylex responses ranged from 17 to 894 ng/ml. No correlation was observed between the baseline Cylex response and subsequent risk of either infection or rejection within 6 months. Lower white blood cell count and African American ethnicity were correlated with a lower Cylex response. CONCLUSIONS: In this study, the Cylex assay had limited utility as an adjunct to routine clinical evaluation in assessing risk of infection or rejection in cardiac transplant recipients.

Effects of early steroid withdrawal after heart transplantation.

BACKGROUND: Managing immunosuppression is a significant aspect of posttransplantation patient care. Previously, our institution reported that prednisone could be withdrawn in cardiac allograft recipients without jeopardizing midterm survival. We returned to this group of patients to investigate the long-term effects of our steroid taper protocol. METHODS: We reviewed the records of 162 consecutive cardiac transplant recipients from our institution. Patients who underwent transplantation between 1988 and 1990 were treated with traditional triple-therapy immunosuppression (cyclosporine, azathioprine, and prednisone). Beginning June 1990, we instituted a protocol of early steroid taper with discontinuation by 6 months after transplant. The two groups were comparable with respect to age, sex, ethnicity, cause of heart failure, ischemic time, body mass index, and creatinine at the time of transplantation. RESULTS: Fifty-seven percent of the patients in the early steroid taper group were successfully withdrawn from steroids at 6 months after transplantation. This group had a decreased freedom from and increased frequency of acute rejection (p < 0.01 for each) when compared with the traditional therapy group. There was, however, no difference in freedom from posttransplant coronary artery disease (p = 0.53). The early steroid taper group enjoyed an increased freedom from malignancy (p = 0.01) and trended toward a decreased frequency of infection (p = 0.10) and improved survival (p = 0.06). CONCLUSIONS: Steroid withdrawal is possible in 57% of patients at 6 months after transplantation. The institution of an early steroid taper protocol improves the overall freedom from malignancies and may decrease the frequency of infection and prolong overall survival without increasing the risk of posttransplant coronary artery disease.

Induction therapy with basiliximab allows delayed initiation of cyclosporine and preserves renal function after cardiac transplantation.

BACKGROUND: Cyclosporine (CsA) is frequently initiated as induction therapy in patients undergoing orthotopic heart transplantation, but our experience has identified a significant rate of post-operative renal dysfunction. We therefore devised a renal-sparing cyclosporine-free induction regimen consisting of the early administration basiliximab, an interleukin-2 receptor monoclonal antibody, followed by the late initiation of cyclosporine on post-operative Day 4. METHODS: Between September 1998 and December 1999, we treated 25 patients at risk for post-operative renal dysfunction (high-risk basiliximab group) with the new induction regimen and another 33 patients not at risk (low-risk CsA group) for renal dysfunction with our standard cyclosporine protocol. We identified a historical control group (1996 through 1998) of 32 patients at risk for renal dysfunction (high-risk CsA group) who had received our standard cyclosporine protocol. RESULTS: The increase in serum creatinine levels after transplantation was less in the high-risk basiliximab group (-0.1 +/- 0.7) than in the high-risk CsA group (0.5 +/- 1.0, p < 0.02) and comparable to the low-risk CsA group (0.03 +/- 0.6). The basiliximab protocol did not increase rejection; the percentage of rejection episodes was high-risk basiliximab, 0; high-risk CsA, 13; and low-risk CsA, 3 (p = .13). CONCLUSION: Basiliximab induction therapy allows delayed initiation of cyclosporine after cardiac transplantation without an increase in rejection and reduces the risk of post-operative renal dysfunction.

Routine computed tomography screening of the chest in high-risk cardiac transplant recipients may improve survival.

BACKGROUND: Multiple studies have demonstrated an increased incidence of lung cancer in the heart transplant population. We reviewed our cardiac transplantation experience with respect to the development of bronchogenic carcinoma and explored the role of routine chest computed tomography (CT) in its surveillance. METHODS: We performed a review of our cardiac transplantation experience, highlighting the incidence of lung cancer, and we analyzed our recent experience with screening chest CT in lung cancer surveillance in this patient group. RESULTS: Eighteen patients developed 20 cases of bronchogenic carcinoma for an incidence of 6.83%. In 10 cases, the patients underwent surgical resection; however, in the remaining cases, the patients were either treated with chemotherapy and/or radiation or they died before initiation of therapy. The actuarial 1-, 2- and 5-year overall survival rates were 49%, 29% and 13%, respectively. The median survival of patients who underwent surgical resection was 28 months (3 to 85 months), whereas the median survival of patients who were either ineligible for surgery or died before initiation of treatment was only 1 month (1 to 13 months). All patients diagnosed with lung cancer by chest CT underwent surgical resection; however, only 37.5% of patients diagnosed with lung cancer by chest X-ray were found at an appropriate stage for resection (p = 0.025). CONCLUSIONS: Cardiac transplant recipients have a significant risk of developing bronchogenic carcinoma. Routine chest CT screening in high-risk patients may enable clinicians to identify disease earlier, which is essential for the option of surgical resection and, therefore, prolonged survival.