Cardiac allograft hypertrophy is associated with impaired exercise tolerance after heart transplantation

Left ventricular apical hypertrophy emerged from the fourth-year post heart transplantation: Case report and literature review

Apical hypertrophic cardiomyopathy (AHCM) is a relatively rare phenotype of hypertrophic cardiomyopathy, which is characterized by focal thickening of the left ventricular (LV) apical myocardium, showing a spade-shaped shadow on the left ventricle. We present the case of a 59-year-old man who was found to have AHCM, is an asymptomatic orthotopic heart transplantation (HTx) patient. This rare and progressive case of LV apical hypertrophy emerged from the fourth year post surgery. We analyzed the etiology of this case and summarized the clinical manifestations and prognosis of AHCM following HTx by reviewing our case and the literature.

Circulating Galectin-3 Levels Are Persistently Elevated After Heart Transplantation and Are Associated With Renal Dysfunction

OBJECTIVES

This study evaluated changes in serum levels of galectin (Gal)-3 before and after heart transplantation (HTx) and assessed the role of pre-HTx Gal-3 as a biomarker for post-HTx outcomes.

BACKGROUND

Gal-3 is a novel biomarker that reflects cardiac remodeling and fibrosis. Elevated serum Gal-3 levels are associated with poor prognosis in heart failure patients. Whether Gal-3 levels change following HTx and the significance of post-HTx outcomes are unknown.

METHODS

Serum Gal-3 levels were measured in 62 patients at 118 days (Interquartile Range [IQR]: 23 to 798 days) before and 365 days (IQR: 54 to 767 days) post HTx. Cardiac tissue taken during routine post-HTx endomyocardial biopsy was evaluated to assess the correlation between tissue Gal-3 staining and serum Gal-3 levels and with the presence of myocardial hypertrophy and fibrosis.

RESULTS

Serum Gal-3 levels remained significantly elevated (>17.8 ng/ml) in 35 patients (56%) post HTx. There was a significant inverse correlation between Gal-3 levels and glomerular filtration rate measured before and after HTx (p > 0.005). There was no association between Gal-3 serum level and Gal-3 staining of myocardial tissue or with the presence of myocyte hypertrophy and interstitial fibrosis post HTx. Elevated pre-HTx Gal-3 levels were associated with reduced post-HTx exercise capacity, but this association was not significant after adjustment for age, body mass index, and glomerular filtration rate.

CONCLUSIONS

This is the first study to demonstrate the fact that Gal-3 levels remain elevated in the majority of patients despite HTx and is associated with renal dysfunction. Our findings suggest Gal-3 is a systemic rather than cardiac-specific biomarker.

Myocyte growth, repair, and oxidative stress following pediatric heart transplantation

Cardiac remodeling is associated with plasma biomarkers of fibrinogenesis, inflammation, and oxidative stress, and upregulation of mitogenic, pro-fibrotic, and apoptotic signaling pathways. Our primary objective was to evaluate biomarker and subcellular myocardial changes in pediatric heart transplant recipients. Fifty-two-week prospective, randomized (tacrolimus, Tac, vs. cyclosporine, CsA), open-label, parallel group study. Serial myocardial biopsies were probed for mitogenic and pro-inflammatory proteins. Plasma biomarkers of oxidative stress (F2α isoprostanes, nitrotyrosine), and inflammation and oxidation (hsCRP and cystatin-C) were measured. Nine of 11 randomized patients completed the study (four Tac, five CsA). Mean levels of F2α isoprostanes, hsCRP, and cystatin-C were maximal at Week 2. Peak activation of all MAP kinases in myocardial tissue was maximal at Week 10; no association was seen with rejection. Cardiac Bax/Bcl-2 levels (index of apoptosis) correlated negatively with F2α isoprostanes at Week 2 (r = -0.88) and with hsCRP at Week 52 (r = -0.67). At Week 52, hsCRP levels correlated positively with molecular indices of cardiac cell growth. We found evidence of systemic and myocardial oxidative damage and inflammation early posttransplant, which may be related to the remodeling process. Further study is needed to better understand the cardiac and systemic repair processes following pediatric heart transplantation.

Changes in cardiopulmonary exercise testing parameters following continuous flow left ventricular assist device implantation and heart transplantation

BACKGROUND

Reduced exercise tolerance from impaired cardiac output is an important criterion for left ventricular assist device (LVAD) implantation. However, little is known about how exercise capacity changes after LVAD and how changes compare with patients undergoing heart transplantation.

METHODS AND RESULTS

We compared changes in cardiopulmonary exercise testing performed pre- and postoperatively in patients who underwent HeartMate II LVAD implantation (n = 25) and heart transplantation (n = 74) at the Mayo Clinic in Rochester, Minnesota, between 2007 and 2012. Preoperatively, patients undergoing LVAD and transplant had markedly reduced exercise time (mean 5.1 minutes [45% predicted] and 5.0 minutes [44% predicted], respectively), low peak oxygen consumption (VO2; mean 11.5 mL · kg · min [43% predicted] and 11.9 mL · kg · min [38% predicted]), and abnormal ventilatory gas exchange (ratio of minute ventilation to carbon dioxide production [VE/VCO2] nadir 39.4 and 37.4). After LVAD and transplant, there were similar improvements in exercise time (mean Δ +1.2 vs. 1.7 minutes, respectively, P = .27) and VE/VCO2 nadir (mean Δ -3.7 vs. -4.2, P = .74). However, peak VO2 increased posttransplant but did not change post-LVAD (mean Δ +5.4 vs. +0.9 mL · kg · min, respectively, P < .001). Most patients (72%) had a peak VO2 < 14 mL · kg · min post-LVAD.

CONCLUSIONS

Although improvements in exercise capacity and gas exchange are seen after LVAD and heart transplant, peak VO2 doesn't improve post-LVAD and remains markedly abnormal in most patients.

LVAD implant as a bridge to heart transplantation is associated with allosensitization as measured by single antigen bead assay

BACKGROUND

Left ventricular assist devices (LVAD) as a bridge (BTT) to heart transplantation (HTX) may be limited by the formation of anti-human leukocyte antigen antibodies. Whether sensitization occurs with continuous axial flow LVAD implant as assessed by single antigen bead (SAB) assay is unknown.

METHODS

Cytotoxic panel-reactive antibody (PRA) and SAB assays were analyzed in HTX recipients undergoing LVAD implant as a BTT. Sensitization was defined as peak anti-human leukocyte antigen antibody values of more than 2000 mean fluorescence intensity because these values have been found to correlate with flow cytometric crossmatch results.

RESULTS

LVADs were implanted as BTT in 30 patients. There were 7% (2 of 30) of patients before LVAD implant and no patients after LVAD implant with PRA more than 10%. However, 20% (6 of 30) of patients before LVAD and 53% (16 of 30) after LVAD were sensitized as measured by SAB (P=0.024). At HTX, 47% (14 of 30) of patients remained sensitized. A positive virtual crossmatch was observed in 28% (4 of 14) of the sensitized patients at HTX. There was no difference between the sensitized and nonsensitized groups (P>0.4 for all) in usage of blood products (6411 vs. 6339 units) and time to HTX (28,663 vs. 25,748 days), and 1 year after HTX, there were no differences in rejection (total rejection score 0.30 vs. 0.37) and survival (93% vs. 88%).

CONCLUSION

Allosensitization after LVAD is common despite cytotoxic PRA being negative. One year after HTX, this sensitization does not translate into increased acute cellular or antibody-mediated rejection or reduced survival.