Plasma NGAL and glomerular filtration rate in cardiac transplant recipients treated with standard or reduced calcineurin inhibitor levels

AIM

Predictors of renal recovery following conversion from calcineurin inhibitor- to proliferation signal inhibitor-based therapy are lacking. We hypothesized that plasma NGAL (P-NGAL) could predict improvement in glomerular filtration rate (GFR) after conversion to everolimus.

PATIENTS & METHODS

P-NGAL was measured in 88 cardiac transplantation patients (median 5 years post-transplant) with renal dysfunction randomized to continuation of conventional calcineurin inhibitor-based immunosuppression or switching to an everolimus-based regimen.

RESULTS

P-NGAL correlated with measured GFR (mGFR) at baseline (R(2) = 0.21; p < 0.001). Randomization to everolimus improved mGFR after 1 year (median [25-75 % percentiles]: ΔmGFR 5.5 [-0.5-11.5] vs -1 [-7-4] ml/min/1.73 m(2); p = 0.006). Baseline P-NGAL predicted mGFR after 1 year (R(2) = 0.18; p < 0.001), but this association disappeared after controlling for baseline mGFR.

CONCLUSION

P-NGAL and GFR correlate with renal dysfunction in long-term heart transplantation recipients. P-NGAL did not predict improvement of renal function after conversion to everolimus-based immunosuppression.

Effect of high-intensity interval training on progression of cardiac allograft vasculopathy

BACKGROUND

Cardiac allograft vasculopathy (CAV) is a progressive form of atherosclerosis occurring in heart transplant (HTx) recipients, leading to increased morbidity and mortality. Given the atheroprotective effect of exercise on traditional atherosclerosis, we hypothesized that high-intensity interval training (HIIT) would reduce the progression of CAV among HTx recipients.

METHODS

Forty-three cardiac allograft recipients (mean ± SD age 51 ± 16 years; 67% men; time post-HTx 4.0 ± 2.2 years), all clinically stable and >18 years old, were randomized to either a HIIT group or control group (standard care) for 1 year. The effect of training on CAV progression was assessed by intravascular ultrasound (IVUS).

RESULTS

IVUS analysis revealed a significantly smaller mean increase [95% CI] in atheroma volume (PAV) of 0.9% [95% CI -;0.3% to 1.9%] in the HIIT group as compared with the control group, 2.5% [1.6% to 3.5%] (p = 0.021). Similarly, the mean increase in total atheroma volume (TAV) was 0.3 [0.0 to 0.6] mm(3)/mm in the HIT group vs 1.1 [0.6 to 1.7] mm(3)/mm in the control group (p = 0.020), and mean increase in maximal intimal thickness (MIT) was 0.02-0.01 to 0.04] mm in the HIIT group vs 0.05 [0.03 to 0.08] mm in the control group (p = 0.054). Qualitative plaque progression (virtual histology parameters) and inflammatory activity (biomarkers) were similar between the 2 groups during the study period.

CONCLUSIONS

HIIT among maintenance HTx recipients resulted in a significantly impaired rate of CAV progression. Future larger studies should address whether exercise rehabilitation strategies should be included in CAV management protocols.

Balloon pulmonary angioplasty in patients with inoperable chronic thromboembolic pulmonary hypertension

OBJECTIVE

To examine the effect of balloon pulmonary angioplasty (BPA) on chronic thromboembolic pulmonary hypertension (CTEPH) in patients with inoperable disease or persistent pulmonary hypertension after pulmonary endarterectomy.

DESIGN

Observational cohort study.

SETTING

Referred patients with inoperable or persistent CTEPH.

PATIENTS

Twenty consecutive CTEPH patients (10 females), aged 60±10 years.

INTERVENTIONS BPA MAIN OUTCOME MEASURES

Right heart catheterisation, functional capacity (cardiopulmonary exercise testing (CPET) and NYHA class) and blood sampled biomarkers N-terminal pro-brain natriuretic peptide (NT-proBNP) and troponin T examined at the time of diagnosis and repeated in all patients 3 months after the last BPA.

RESULTS

Seventy-three catheterisations were performed with 18.6±6.1 BPAs per patient on segmental and subsegmental arteries. Two deaths occurred following the first BPA, with an overall 10% periprocedural death rate. Reperfusion oedema complicated seven procedures. Comparisons before and after BPA showed significant haemodynamic improvements, including decreased mean pulmonary artery pressure (mPAP) (45±11 mm Hg vs 33±10 mm Hg; p<0.001) and increased cardiac output (4.9±1.6 L/min vs 5.4±1.9 L/min; p=0.011). Reduced right ventricular strain was indicated by significantly lower plasma levels of NT-proBNP and troponin T. Significant improvement in functional capacity was evident as assessed by NYHA class (3.0±0.5 vs 2.0±0.5; p<0.001) and CPET (13.6±5.6 mL/kg/min vs 17.0±6.5 mL/kg/min; p<0.001). Seventeen patients (85%) were alive after 51±30 months of follow-up.

CONCLUSIONS

BPA may offer an alternative form of treatment in selected CTEPH patients. While prognostic markers such as haemodynamics, functional capacity and biomarkers improve, significant periprocedural complications must be recognised. Randomised trials are warranted.

Virtual histology assessment of cardiac allograft vasculopathy following introduction of everolimus--results of a multicenter trial

In this 12-month multicenter Scandinavian study, 78 maintenance heart transplant (HTx) recipients randomized to everolimus with reduced calcineurin inhibitor (CNI) exposure or continued standard CNI-therapy underwent matched virtual histology (VH) examination to evaluate morphological progression of cardiac allograft vasculopathy (CAV). Parallel measurement of a range of inflammatory markers was also performed. A similar rate of quantitative CAV progression was observed in the everolimus (n = 30) and standard CNI group (n = 48) (plaque index 1.9 ± 3.8% and 1.6 ± 3.9%, respectively; p = 0.65). However, VH analysis revealed a significant increase in calcified (2.4 ± 4.0 vs. 0.3 ± 3.1%; p = 0.02) and necrotic component (6.5 ± 8.5 vs. 1.1 ± 8.6%; p = 0.01) among everolimus patients compared to controls. The increase in necrotic and calcified components was most prominent in everolimus patients with time since HTx >5.1 years and was accompanied by a significant increase in levels of von Willebrand (vWF) factor (p = 0.04) and vascular cell adhesion molecule (VCAM) (p = 0.03). Conversion to everolimus and reduced CNI is associated with a significant increase in calcified and necrotic intimal components and is more prominent in patients with a longer time since HTx. A significant increase in vWF and VCAM accompanied these qualitative changes and the prognostic implication of these findings requires further investigation.

Muscular exercise capacity and body fat predict VO(2peak) in heart transplant recipients

BACKGROUND

Heart transplant (HTx) recipients usually have reduced exercise capacity, with reported VO2peak levels of 50-70% of predicted values. This study aimed to evaluate central and peripheral factors predictive of VO2peak.

METHODS AND RESULTS

Fifty-one clinically stable HTx recipients >18 years old and 1-8 years after HTx, underwent maximal exercise testing on a treadmill. Clinical laboratory, haemodynamic and echocardiographic data, lung function, and isokinetic muscle strength and muscular exercise capacity were recorded. The mean ± SD age was 52 ± 16 years, 71% were male, and time from HTx was 4.1 ± 2.2 years. The patients were assigned to one of two groups: VO2peak ≤or >27.3 ml/kg/min, which was the median value, corresponding to 80% of predicted value. The group with the higher VO2peak had significantly lower body mass index, body fat, and triglycerides, and significantly higher body water, muscular exercise capacity, high-density lipoprotein (HDL) cholesterol, lung function, mitral annular velocity, peak ventilation, O2 pulse, and VE/VCO2 slope. Donor age, recipient age, sex, medication, ischaemic time, cardiac dimensions, systolic function, and chronotropic responses during exercise were similar. Multiple regression analysis showed that muscular exercise capacity and body fat were the strongest VO2peak predictors.

CONCLUSIONS

Chronotropic incompetence is not a limiting factor for exercise capacity in a population of relatively fit HTx patients. The most significant predictors, representing only peripheral factors, are similar to those often determining VO2peak in healthy, non-athletic individuals. Our findings emphasize the importance of a low percentage of body fat and high muscular exercise capacity in order to attain a sufficient VO2peak level after HTx.

Pregnancy in heart- and heart/lung recipients can be problematic

OBJECTIVE

The first successful pregnancy after heart transplantation was reported in 1988. Worldwide experience with heart and heart/lung transplanted (H-HLTx) pregnant women is limited. To expand this knowledge the collaborating Nordic thoracic transplant centers wanted to collect information on all such pregnancies from their centers.

DESIGN

Information was retrospectively collected on all H-HLTx pregnancies in the Nordic countries.

RESULTS

A total of 25 women have had 42 pregnancies and all survived the gestation. Minor complications were increasing incidence of proteinuria, hypertension and diabetes. Major problems were two rejections (early post partum), two severe renal failures, seven pre-eclampsias and 17 abortions. Five women died two to 12 years after delivery. Of 25 live born children, one was born with cancer and one died early after inheriting the mother's cardiomyopathy.

CONCLUSION

Pregnancy after H-HLTx can be successful for both mother and child. There are, however, many obstacles which should be addressed. Respecting the couple's desire for children the attitude should be carefully, not too optimistic, after proper pre-pregnant information and counseling. Delivery should preferably take place at the transplant center.

Assessment of right pump outflow banding and speed changes on pulmonary hemodynamics during biventricular support with two rotary left ventricular assist devices

The absence of an effective, easily implantable right ventricular assist device (RVAD) significantly diminishes long-term treatment options for patients with biventricular heart failure. The implantation of a second rotary left ventricular assist device (LVAD) for right heart support is therefore being considered; however, this approach exhibits technical challenges when adapting current devices to produce the lower pressures required of the pulmonary circulation. Hemodynamic adaptation may be achieved by either reducing the rotational speed of the right pump impeller or reducing the diameter of the right outflow cannula by the placement of a restricting band; however, the optimal value and influence of changes to each parameter are not well understood. Hemodynamics were therefore investigated using different banding diameters of the right outflow cannula (3-6.5 mm) and pump speeds (500-4500 rpm), using two identical rotary blood pumps coupled to a pulsatile mock circulation loop. Reducing the speed of the right pump from 4900 rpm (for left ventricle support) to 3500 rpm, or banding the Ø10 mm (area 78.5 mm²) right outflow graft to Ø5.4 mm (22.9 mm²) produced suitable hemodynamics. Pulmonary pressures were most sensitive to banding diameters, especially when RVAD flow exceeded LVAD flow. This occurred between Ø5.3 and Ø6.5 mm (22.05-38.5 mm²) and speeds between 3200 and 4400 rpm, with the flow imbalance potentially leading to pulmonary congestion. Total flow was not affected by banding diameters and speeds below this range, and only increased slightly at higher values. Both right outflow banding or right pump speed reduction were found to be effective techniques to allow a rotary LVAD to be used directly for right heart support. However, the observed sensitivity to diameter and speed indicate that challenges may be presented when setting appropriate values for each patient, and control over these parameters is desirable.

[Treatment of idiopathic pulmonary arterial hypertension]

BACKGROUND

In the past 5-10 years, drug treatment of idiopathic pulmonary arterial hypertension has evolved considerably. Experience and results from use of such updated treatment in Norway has not been reported.

MATERIAL AND METHOD

32 patients newly diagnosed with idiopathic pulmonary arterial hypertension, were consecutively assessed with respect to hemodynamics and physical capacity. The results after three months were compared with those after 12 months. Observed survival was compared with estimated survival from the time when only conventional treatment was available.

RESULTS

The patients (78% women) were 42 ± 14 years, had dyspnea in NYHA class 2.9 ± 0.4 and a maximal oxygen uptake of 12.0 ± 3.9 ml/kg/min (37 ± 13% of the expected). Updated treatment led to significantly improved hemodynamics and physical capacity, which persisted during follow-up. During 43 ± 31 months follow-up, seven patients died while two underwent bilateral lung transplantation. Observed transplantation-free survival was 81% after one, two and three years, while that for estimated transplantation-free survival was 70%, 58% and 49% respectively.

INTERPRETATION

Treatment of idiopathic pulmonary arterial hypertension with updated treatment improves hemodynamics and thereby symptoms. Mortality remains high, but is probably lower than it was when only conventional treatment was available.

Systemic markers of inflammation are associated with cardiac allograft vasculopathy and an increased intimal inflammatory component

We evaluated an extensive profile of clinical variables and immune markers to assess the inflammatory milieu associated with cardiac allograft vasculopathy (CAV) assessed by intravascular ultrasound (IVUS) and virtual histology (VH). In total, 101 heart transplant (HTx) recipients were included and underwent IVUS/VH examination and measurement of plasma C-reactive protein (CRP), soluble tumor necrosis factor receptor-1, interleukin-6, osteoprotegerin, soluble gp130, von Willebrand factor, vascular cell adhesion molecule-1 (VCAM-1) and neopterin. Mean Maximal Intimal Thickness (MIT) was 0.61 +/- 0.19 mm and mean fibrotic, fibrofatty, dense calcified and necrotic core components were 55 +/- 15, 14 +/- 10, 15 +/- 13 and 17 +/- 9%, respectively. In multivariate analysis, CRP > 1.5 mg/L (OR 4.6, p < 0.01), VCAM-1 > 391 ng/mL (adjusted OR 3.2, p = 0.04) and neopterin > 7.7 nmol/L (OR 3.8, p = 0.02) were independently associated with MIT > 0.5 mm. Similarly, CRP > 1.5 mg/L (OR 3.7, p < 0.01) and VCAM-1 > 391 (OR 2.7, p = 0.04) were independently associated with an increased intimal inflammatory component (dense calcified/necrotic core component > 30%). Advanced CAV is associated with elevated CRP, VCAM-1 and neopterin and the two former biomarkers are also associated with an increased intimal inflammatory component. Forthcoming studies should clarify if routine measurements of these markers can accurately identify HTx recipients at risk of developing advanced CAV and vulnerable lesions.

Everolimus with reduced calcineurin inhibitor in thoracic transplant recipients with renal dysfunction: a multicenter, randomized trial

BACKGROUND

The proliferation signal inhibitor everolimus offers the potential to reduce calcineurin inhibitor (CNI) exposure and alleviate CNI-related nephrotoxicity. Randomized trials in maintenance thoracic transplant patients are lacking.

METHODS

In a 12-month, open-labeled, multicenter study, maintenance thoracic transplant patients (glomerular filtration rate > or =20 mL/min/1.73m and <90 mL/min/1.73 m) >1 year posttransplant were randomized to continue their current CNI-based immunosuppression or start everolimus with predefined CNI exposure reduction.

RESULTS

Two hundred eighty-two patients were randomized (140 everolimus, 142 controls; 190 heart, 92 lung transplants). From baseline to month 12, mean cyclosporine and tacrolimus trough levels in the everolimus cohort decreased by 57% and 56%, respectively. The primary endpoint, mean change in measured glomerular filtration rate from baseline to month 12, was 4.6 mL/min with everolimus and -0.5 mL/min in controls (P<0.0001). Everolimus-treated heart and lung transplant patients in the lowest tertile for time posttransplant exhibited mean increases of 7.8 mL/min and 4.9 mL/min, respectively. Biopsy-proven treated acute rejection occurred in six everolimus and four control heart transplant patients (P=0.54). In total, 138 everolimus patients (98.6%) and 127 control patients (89.4%) experienced one or more adverse event (P=0.002). Serious adverse events occurred in 66 everolimus patients (46.8%) and 44 controls (31.0%) (P=0.02).

CONCLUSION

Introduction of everolimus with CNI reduction offers a significant improvement in renal function in maintenance heart and lung transplant recipients. The greatest benefit is observed in patients with a shorter time since transplantation.

Benefit of early conversion from CNI-based to everolimus-based immunosuppression in heart transplantation

BACKGROUND

Calcineurin inhibitor (CNI)-induced nephrotoxicity is a feared adverse effect after heart transplantation (HTx). In patients with advanced renal failure we performed an overnight conversion from cyclosporine (CsA) to everolimus within the first year after HTx and compared changes in renal function to a similar switch performed in a group of long-term HTx survivors with 24-month follow up.

METHODS

Sixteen HTx recipients (Group 1), including 5 patients undergoing dialysis, were switched overnight from CsA to everolimus at 5.5 (range 1.3 to 8.5) months post-operatively, whereas 15 patients completed 24 months of follow-up. Fifteen long-term survivors (Group 2) were recruited at 96 (58 to 148) months post-HTx. Due to 3 withdrawals and 2 deaths, 10 of these 15 patients remained available for follow-up assessment.

RESULTS

In Group 1 patients, creatinine level improved from 211 (186 to 263) to 112 (98 to 140) mumol/liter and estimated glomerular filtration rate (eGFR) from 29 (20 to 35) to 62 (43 to 69) ml/min/1.73 m(2) (p < 0.001). In Group 2, creatinine decreased from 227 (188 to 255) to 193 (150 to 250) micromol/liter (p = 0.299), and eGFR increased from 26 (21 to 31) to 28 (22 to 35) ml/min/1.73 m(2) (p = 0.225). Four cellular rejections were treated successfully in Group 1. All together, 24 adverse events occurred.

CONCLUSIONS

These preliminary data are the first to suggest that the improvement in renal function after switching to CNI-free everolimus treatment has the greatest potential within the first year post-HTx. While we await randomized, controlled trials, it appears that conversion can be performed with acceptable safety in selected patients.