Adipose Gene Expression Profile Changes With Lung Allograft Reperfusion

Obesity is a risk factor for primary graft dysfunction (PGD), a form of lung injury resulting from ischemia-reperfusion after lung transplantation, but the impact of ischemia-reperfusion on adipose tissue is unknown. We evaluated differential gene expression in thoracic visceral adipose tissue (VAT) before and after lung reperfusion. Total RNA was isolated from thoracic VAT sampled from six subjects enrolled in the Lung Transplant Body Composition study before and after allograft reperfusion and quantified using the Human Gene 2.0 ST array. Kyoto Encyclopedia of Genes and Genomes pathway analysis revealed enrichment for genes involved in complement and coagulation cascades and Jak-STAT signaling pathways. Overall, 72 genes were upregulated and 56 genes were downregulated in the postreperfusion time compared with baseline. Long pentraxin-3, a gene and plasma protein previously associated with PGD, was the most upregulated gene (19.5-fold increase, p = 0.04). Fibronectin leucine-rich transmembrane protein-3, a gene associated with cell adhesion and receptor signaling, was the most downregulated gene (4.3-fold decrease, p = 0.04). Ischemia-reperfusion has a demonstrable impact on gene expression in visceral adipose tissue in our pilot study of nonobese, non-PGD lung transplant recipients. Future evaluation will focus on differential adipose tissue gene expression and the development of PGD after transplant.

Left and Right Ventricular Functional Dynamics Determined by Echocardiograms Before and After Lung Transplantation

Impaired cardiac function is considered a contraindication for lung transplantation (LT). Because right ventricular (RV) function is expected to improve after LT, poor left ventricular (LV) function is often the determinant for LT eligibility. However, the changes in cardiac function before and after LT have not yet been elucidated. Therefore, we reviewed echocardiograms obtained from 67 recipients before and after LT. In a subset of 49 patients, both RV and LV longitudinal strains based on 2-dimensional speckle tracking echocardiography were analyzed. The cardiopulmonary exercise tests were also reviewed. All patients showed significant improvements in their exercise capacity after LT. RV echo parameters improved in all patients after LT (RV fractional area change: 36.7 ± 5.6% to 41.5 ± 2.7%, RV strain: -15.5 ± 2.9% to -18.0 ± 2.1%, RV E/E': 8.4 ± 1.8 to 7.7 ± 1.8; all p <0.05). Overall, the left ventricular ejection fraction (LVEF) did not change (58.7 ± 6.0% to 57.5 ± 9.7%, p = 0.385); however, 20 patients (30%) showed >10% decrease in LVEF after LT (61.5 ± 6.1% to 47.3 ± 4.2%, p <0.001) and an increase in LV E/E' (11.8 ± 1.8 to 12.9 ± 2.2, p = 0.049). Multivariate logistic regression analysis revealed that pre-LT LV E/E' was associated with decrease in LVEF after LT (odds ratio 1.381, 95% confidence interval 1.010 to 1.947, p = 0.043). Furthermore, patients with strain data showed that lower pre-LT LV strain was independently associated with LVEF decrease after LT (odds ratio 1.293, 95% confidence interval 1.088 to 1.614, p = 0.002). Although RV function improves after LT, LV systolic and diastolic functions deteriorate in a sizable proportion of patients. Impaired LV diastolic function before transplant appears to increase the risk of LVEF deterioration after LT.

Combination of liver biopsy with MELD-XI scores for post-transplant outcome prediction in patients with advanced heart failure and suspected liver dysfunction

BACKGROUND

Functional and structural liver abnormalities may be found in patients with advanced heart failure (HF). The Model of End-Stage Liver Disease Excluding INR (MELD-XI) score allows functional risk stratification of HF patients on and off anti-coagulation awaiting heart transplantation (HTx), but these scores may improve or worsen depending on bridging therapies and during time on the waiting list. Liver biopsy is sometimes performed to assess for severity of fibrosis. Uncertainty remains whether biopsy in addition to MELD-XI improves prediction of adverse outcomes in patients evaluated for HTx.

METHODS

Sixty-eight patients suspected of advanced liver disease underwent liver biopsy as part of their HTx evaluation. A liver risk score (fibrosis-on-biopsy + 1) × MELD-XI was generated for each patient.

RESULTS

Fifty-two patients were listed, of whom 14 had mechanical circulatory support (MCS). Thirty-six patients underwent transplantation and 27 patients survived ≥1 year post-HTx (74%, as compared with 88% average 1-year survival in HTx patients without suspected liver disease; p < 0.01). Survivors had a lower liver risk score at evaluation for HTx (31.0 ± 20.4 vs 65.2 ± 28.6, p < 0.01). A cut-point of 45 for liver risk score was identified by receiver-operating-characteristic (ROC) analysis. In the analysis using Cox proportional hazards models, a liver risk score ≥45 at evaluation for HTx was associated with greater risk of death at 1 year post-HTx compared with a score of <45 in both univariable (HR 3.94, 95% CI 1.77-8.79, p < 0.001) and multivariable (HR 4.35, 95% CI 1.77-8.79, p < 0.001) analyses. Patients who died <1 year post-HTx had an increased frequency of acute graft dysfunction (44.4% vs 3.7%, p = 0.009), longer ventilation times (55.6% vs 11.1%, p = 0.013) and severe bleeding events (44.4% vs 11.1%, p = 0.049). The liver risk score at evaluation for HTx also predicted 1-year mortality after HTx listing (p < 0.001).

CONCLUSIONS

Patients with HF and advanced liver dysfunction are high-risk HTx candidates. Liver biopsy in addition to MELD-XI improves risk stratification of patients with advanced HF and suspected irreversible liver dysfunction.

Risk stratification of ambulatory patients with advanced heart failure undergoing evaluation for heart transplantation

BACKGROUND

Risk stratification of ambulatory heart failure (HF) patients has relied on peak VO(2)<14 ml/kg/min. We investigated whether additional clinical variables might further specify risk of death, ventricular assist device (VAD) implantation (INTERMACS <4) or heart transplantation (HTx, Status 1A or 1B) within 1 year after HTx evaluation. We hypothesized that right ventricular stroke work index (RVSWI), pulmonary capillary wedge pressure (PCWP) and the model for end-stage liver disease-albumin score (MELD-A) would be additive prognostic predictors.

METHODS

We retrospectively collected data on 151 ambulatory patients undergoing HTx evaluation. Primary outcomes were defined as HTx, LVAD or death within 1 year after evaluation.

RESULTS

Average age in our cohort was 55 ± 11.1 years, 79.1% were male and 39% had an ischemic etiology (LVEF 21 ± 10.5% and peak VO(2) 12.6 ± 3.5 ml/kg/min). Fifty outcomes (33.1%) were observed (27 HTxs, 15 VADs and 8 deaths). Univariate logistic regression showed a significant association of RVSWI (OR 0.47, p = 0.036), PCWP (OR 2.65, p = 0.007) and MELD-A (OR 2.73, p = 0.006) with 1-year events. Stepwise regression showed an independent correlation of RVSWI<5gm-m(2)/beat (OR 6.70, p < 0.01), PCWP>20 mm Hg (OR 5.48, p < 0.01), MELD-A>14 (OR 3.72, p< 0.01) and peak VO(2)<14 ml/kg/min (OR 3.36, p = 0.024) with 1-year events. A scoring system was developed: MELD-A>14 and peak VO(2)<14-1 point each; and PCWP>20 and RVSWI<5-2 points each. A cut-off at≥4 demonstrated a 54% sensitivity and 88% specificity for 1-year events.

CONCLUSIONS

Ambulatory HF patients have significant 1-year event rates. Risk stratification based on exercise performance, left-sided congestion, right ventricular dysfunction and liver congestion allows prediction of 1-year prognosis. Our findings support early and timely referral for VAD and/or transplant.