Stabilization of Rapidly Progressive Cardiac Allograft Vasculopathy Using mTOR Inhibition After Heart Transplantation.

BACKGROUND: Inhibition of the mammalian target of rapamycin (mTor) pathway after heart transplantation has been associated with reduced progression of coronary allograft vasculopathy (CAV). The application of low-dose mTOR inhibition in the setting of modern immunosuppression, including tacrolimus, remains an area of limited exploration. METHODS: This retrospective study included patients who received heart transplantation between January 2009 and January 2019 and had baseline, 1-year and 2-3-year coronary angiography with intravascular ultrasound (IVUS). Intimal thickness in 5 segments along the left anterior descending artery was compared across imaging time points in patients who were transitioned to low-dose mTOR inhibitor (sirolimus) vs standard treatment with mycophenolate on a background of tacrolimus. Long-term adverse cardiovascular outcomes (revascularization, severe CAV, retransplant, and cardiovascular death) were also assessed. RESULTS: Among 216 patients (mean age 51.5 ± 11.9 years, 77.8% men, 80.1% white), 81 individuals (37.5%) were switched to mTOR inhibition. mTOR inhibition was associated with a reduction in intimal thickness by 0.05 mm (95% CI 0.02-0.07; P < 0.001). This reduction was driven by patients who met the criteria for rapidly progressive CAV 1-year post-transplant (0.12 mm; P = 0.016 for interaction). After a median follow-up of 8.6 (IQR 6.6-11) years, 40 patients had major adverse cardiovascular outcomes. The use of mTOR inhibitors was not significantly associated with cardiovascular outcomes (P = 0.669). CONCLUSION: Transitioning patients after heart transplantation to an immunosuppression regimen composed of low-dose mTOR inhibition and tacrolimus was associated with a lack of progression of CAV, particularly in those with rapidly progressive CAV at 1 year, but not with long-term cardiovascular outcomes.

PCSK9 Inhibitors in Heart Transplant Patients: Safety, Efficacy, and Angiographic Correlates.

BACKGROUND: Statins are recommended in heart transplant patients, but are sometimes poorly tolerated. Alternative agents are often considered including proprotein convertase subtilisin/kexin type-9 inhibitors (PCSK9i). We sought to investigate the use of PCSK9i after heart transplantation. METHODS AND RESULTS: We identified patients who received a heart transplant from 1999 to 2019 and were started on PCSK9i at our institution. Clinical, laboratory, and coronary angiography with intravascular ultrasound results were compared. Among 65 patients initiated on PCSK9i (48 for statin intolerance and 17 for refractory hyperlipidemia), the median time from transplant was 5.5 years (interquartile range [IQR], 2.8-9.9 years) with a median PCSK9 treatment duration of 1.6 years (IQR, 0.8-3.2 years) and 80% still on treatment. Evolocumab was used in 73.8%, alirocumab in 12.3%, and both in 13.8% owing to insurance coverage. All patients required prior authorization; initial denial occurred in 18.5% and 32.3% had denials in subsequent years. The median low-density lipoprotein cholesterol decreased from 130 mg/dL (IQR, 102-148 mg/dL) to 55 mg/dL (IQR, 35-74 mg/dL) after starting PCSK9i (P < .001), with 72% of patients achieving a low-density lipoprotein cholesterol of <70 mg/dL after treatment. There were also significant reductions of total cholesterol, non-high-density lipoprotein cholesterol, total/high-density lipoprotein cholesterol ratio, and triglycerides, with a modest increase in high-density lipoprotein cholesterol. These changes were durable at latest follow-up. In 33 patients with serial coronary angiography and intravascular ultrasound, PCSK9i were associated with stable coronary plaque thickness and lumen area. CONCLUSIONS: Among heart transplant recipients, PCSK9i are effective in lowering cholesterol levels and stabilizing coronary intimal hyperplasia with minimal side effects. Despite favorable effects, access and affordability remain a challenge.

Influence of Donor Transmitted and Rapidly Progressive Coronary Vascular Disease on Long-Term Outcomes After Heart Transplantation: A Contemporary Intravascular Ultrasound Analysis.

BACKGROUND: Donor-transmitted atherosclerosis (DTA) and rapidly progressive cardiac allograft vasculopathy (CAV) at 1 year are intravascular ultrasound (IVUS)-derived measures shown to predict adverse cardiovascular outcomes in the setting of early generation immunosuppressive agents. Given the paucity of data on the prognostic value of IVUS-derived measurements in the current era, we sought to explore their association with adverse outcomes after heart transplantation. METHODS AND RESULTS: This is a retrospective cohort analysis of patients who underwent heart transplantation at our center between January 2009 and June 2016 with baseline and 1-year IVUS. Five IVUS sections were prospectively analyzed for intimal thickness and lumen area. DTA was defined as maximum intimal thickness of 0.5 mm or greater at baseline, and rapidly progressive CAV as an increase in maximum intimal thickness by 0.5 mm or more at 1 year. Our primary analysis assessed the relationship of IVUS and other clinical data on a composite outcome: coronary intervention, CAV stage 2 or 3 (defined by the International Society for Heart and Lung Transplantation 2010 nomenclature), or cardiovascular death. Among 249 patients (mean age 51.0 ± 12.2 years and 74.3% male) included in the analysis, DTA was detected in 118 patients (51.4%). Over a median follow-up of 6.1 years (interquartile range 4.2-8.0 years), 45 patients met the primary end point (23 percutaneous coronary intervention, 11 CAV 2 or 3, and 11 cardiovascular deaths as first event). DTA and rapidly progressive CAV were not associated with the primary end point, all-cause mortality, or retransplantation. In an additional analysis including post-transplant events, incident rejection was strongly associated with poor outcomes, although cytomegalovirus infection was not. CONCLUSIONS: In this contemporary cohort, IVUS-derived DTA and rapidly progressive CAV were not associated with medium- to long-term adverse events after heart transplantation.

Wearable defibrillator use in heart failure (WIF): results of a prospective registry.

BACKGROUND: Heart failure (HF) patients have a high risk of death, and implantable cardioverter defibrillators (ICDs) are effective in preventing sudden cardiac death (SCD). However, a certain percentage of patients may not be immediate candidates for ICDs, particularly those having a short duration of risk or an uncertain amount of risk. This includes the newly diagnosed patients, as well as those on the cardiac transplant list or NYHA class IV heart failure patients who do not already have an ICD. In these patients, a wearable cardioverter defibrillator (WCD) may be used until long term risk of SCD is defined. The purpose of this study was to determine the incidence of SCD in this population, and the efficacy of early defibrillation by a WCD. METHODS: Ten enrolling centers identified 89 eligible HF patients who were either listed for cardiac transplantation, diagnosed with dilated cardiomyopathy, or receiving inotropic medications. Data collected included medical history, device records, and outcomes (including 90 day mortality). RESULTS: Out of 89 patients, final data on 82 patients has been collected. Patients wore the device for 75±58 days. Mean age was 56.8±13.2, and 72% were male. Most patients (98.8%) were diagnosed with dilated cardiomyopathy with a low ejection fraction (<40%) and twelve were listed for cardiac transplantation. Four patients were on inotropes. There were no sudden cardiac arrests or deaths during the study. Interestingly, 41.5% of patients were much improved after WCD use, while 34.1% went on to receive an ICD. CONCLUSIONS: In conclusion, the WCD monitored HF patients until further assessment of risk. The leading reasons for end of WCD use were improvement in left ventricular ejection fraction (LVEF) or ICD implantation if there was no significant improvement in LVEF.

Detection of cardiac allograft rejection and response to immunosuppressive therapy with peripheral blood gene expression.

BACKGROUND: Assessment of gene expression in peripheral blood may provide a noninvasive screening test for allograft rejection. We hypothesized that changes in peripheral blood expression profiles would correlate with biopsy-proven rejection and would resolve after treatment of rejection episodes. METHODS AND RESULTS: We performed a case-control study nested within a cohort of 189 cardiac transplant patients who had blood samples obtained during endomyocardial biopsy (EMB). Using Affymetrix HU133A microarrays, we analyzed whole-blood expression profiles from 3 groups: (1) control samples with negative EMB (n=7); (2) samples obtained during rejection (at least International Society for Heart and Lung Transplantation grade 3A; n=7); and (3) samples obtained after rejection, after treatment and normalization of the EMB (n=7). We identified 91 transcripts differentially expressed in rejection compared with control (false discovery rate <0.10). In postrejection samples, 98% of transcripts returned toward control levels, displaying an intermediate expression profile for patients with treated rejection (P<0.0001). Cluster analysis of the 40 transcripts with >25% change in expression levels during rejection demonstrated good discrimination between control and rejection samples and verified the intermediate expression profile of postrejection samples. Quantitative real-time polymerase chain reaction confirmed significant differential expression for the predictive markers CFLAR and SOD2 (UniGene ID No. 355724 and No. 384944). CONCLUSIONS: These data demonstrate that peripheral blood expression profiles correlate with biopsy-proven allograft rejection. Intermediate expression profiles of treated rejection suggest persistent immune activation despite normalization of the EMB. If validated in larger studies, expression profiling may prove to be a more sensitive screening test for allograft rejection than EMB.