Influence of Blood Pressure and Calcineurin Inhibitors on Kidney Function After Heart or Liver Transplantation

Etiology, risk factors and management of hypertension post liver transplantation

BACKGROUND

Cardiovascular events are one of the most important causes of morbidity and mortality in the long-term follow-up of liver transplant recipients. Hypertension is a significant cardiovascular risk factor that occurs frequently after pediatric liver transplantation. Chronic use of immunosuppressants - mainly calcineurin inhibitors - plays a major role in the development of post-transplant hypertension and circadian disturbances such as flattening of the nocturnal blood pressure dip. This requires special attention in children given the long timeframe during which immunosuppressive therapy is necessary. Careful and structured blood pressure monitoring and adequate treatment of hypertension are essential to optimize the quality of life and life expectancy of pediatric liver transplant patients. However, evidence-based guidelines for monitoring and management of post-transplant hypertension and its complications are lacking.

METHODS

We conducted a comprehensive review of the current knowledge and practices concerning post-transplant hypertension. The databases Pubmed, Embase, Web of Science and Google Scholar were scanned with the following keywords: pediatric liver transplantation, immunosuppression, tacrolimus, cardiovascular effects, hypertension, heart function, kidney function, circadian rhythm, mechanism, monitoring, and management.

RESULTS

In this review, we describe the incidence and etiology of hypertension in pediatric liver transplant recipients, the underlying mechanisms and characteristics of calcineurin inhibitor-induced hypertension, and the consequences of and risk factors for post-transplant hypertension. We hereby present an overview of the current practices in blood pressure monitoring and antihypertensive treatment as well as an algorithm for the evaluation and management of hypertension post liver transplantation. Finally, we discuss knowledge gaps and suggestions for future research.

Renal Dysfunction After Heart Transplant

BACKGROUND

Moderate or severe renal dysfunction (MSRD) is a frequent complication after heart transplantation. Strategies to delay progression and improve outcomes, such as renoprotective medications and timely referral to nephrology, remain important in providing care to heart transplant recipients with MSRD.

RESEARCH QUESTION

What are chronic renal dysfunction's prevalence, risk factors, and optimal clinical management strategies in heart transplant recipients?

DESIGN

This single-center, cross-sectional study examined patients who received a heart transplant from January 1, 2000, to June 30, 2011, and followed until December 31, 2011. Moderate or severe renal dysfunction was defined as a glomerular filtration rate of <60 mL/min/1.73 m2.

RESULTS

The prevalence of MSRD among 195 heart transplant recipients was 60%. Variables associated with MSRD were female sex (odds ratio [OR]: 4.82; 95% CI, 1.72-13.54), greater age (OR: 1.10 per year; 95% CI, 1.06-1.14), time since transplant (OR: 1.0004 per year; 95% CI, 1.0001-1.0007), and mTOR inhibitor use (OR: 2.89; 95% CI, 1.24-6.71). Tacrolimus use (OR: 0.19; 95% CI, 0.05-0.71) and cyclosporine use (OR: 0.21; 95% CI, 0.05-0.80) were associated with patients without MSRD. Among patients with MSRD, 19.6% were referred to a nephrologist. Median eGFR remained stable at approximately 60 mL/min/1.73 m2 for 3 years after the study.

CONCLUSIONS

Our results suggest that female sex, older age at transplant, and time since transplant are associated with MSRD in heart transplant recipients. Tacrolimus and cyclosporine use seemed renoprotective, but lower usage and increased mTOR inhibitor use may more likely indicate existing treatment patterns for patients with MSRD.

Kidney Disease after Heart and Lung Transplantation

Chronic kidney disease (CKD) is not only common after lung and heart transplantation but also is associated with increased morbidity and mortality due to multiple pre-, peri- and post-transplant factors. While the exact incidence of CKD in this population is not well-defined, it seems to have gradually increased over the years as older recipients are more frequently considered. The increasing success of the procedure and expanding transplant candidate pool has allowed many with comorbid conditions to receive a transplant, which was considered prohibitive in the past. This review presents risk factors that have been linked to CKD as well as interventions that may help alleviate this serious problem. The impact of pretransplant renal function and the overexaggerated role of chronic nephrotoxicity of calcineurin inhibitors is discussed in detail. Until the exact pathophysiology of kidney disease is better understood, there is a dire need to expand the research agenda beyond observational studies.

Targeting Calcineurin Inhibitor-Induced Arterial Hypertension in Liver Transplanted Children Using Hydrochlorothiazide

OBJECTIVE

Arterial hypertension (AH) is the most common toxic effect of calcineurin inhibitor (CNI)-based immunosuppression in children after liver transplantation (LT). Activation of the renal sodium chloride cotransporter (NCC) by CNIs has been described as a major cause of CNI-induced AH. Thiazides, for example, hydrochlorothiazide (HCTZ), can selectively block the NCC and may ameliorate CNI-induced AH after pediatric LT.

METHODS

From 2005 thru 2015 we conducted a retrospective, single-center analysis of blood pressure in 2 pediatric cohorts (each n = 33) with or without HCTZ in their first year after LT. All patients received CNI-based immunosuppression. According to AAP guidelines, AH was defined as stage 1 and stage 2. Cohort 1 received an HCTZ-containing regimen to target the CNI-induced effect on the NCC, leading to AH. Cohort 2 received standard antihypertensive therapy without HCTZ.

RESULTS

In children who have undergone LT and been treated with CNI, AH overall was observed less frequently in cohort 1 vs cohort 2 (31% vs 44%; ns). Moreover, severe AH (stage 2) was significantly lower in cohort 1 vs 2 (1% vs 18%; p < 0.001). Multivariate analysis revealed HCTZ as the only significant factor with a protective effect on occurrence of severe stage 2 AH. While monitoring safety and tolerability, mild asymptomatic hypokalemia was the only adverse effect observed more frequently in cohort 1 vs 2 (27% vs 3%; p = 0.013).

CONCLUSIONS

Targeting NCC by HCTZ significantly improved control of severe CNI-induced AH and was well tolerated in children who underwent LT. This effect may reduce the risk of long-term end-organ damage and improve quality of life.

Acute kidney injury and chronic kidney disease after liver transplant: A retrospective observational study

BACKGROUND AND RATIONALE

Chronic kidney disease remains an important risk factor for morbidity and mortality among LT recipients, but its exact incidence and risk factors are still unclear.

MATERIAL AND METHODS

We carried out a retrospective cohort study of consecutive adults who underwent liver transplant (January 2009-December 2018) and were followed (at least 6 months) at our institution. CKD was defined following the Kidney Disease: Improving Global Outcomes (KDIGO) 2012 Clinical Practice Guidelines. Long-term kidney function was classified into 4 groups: no CKD (eGFR, ≥60mL/min/1.73m²), mild CKD (eGFR, 30-59mL/min/1.73m²), severe CKD (eGFR, 15-29mL/min/1.73m²), and end-stage renal disease (ESRD).

RESULTS

We enrolled 410 patients followed for 53.2±32.6 months. 39 had CKD at baseline, and 95 developed de novo CKD over the observation period. There were 184 (44.9%) anti-HCV positive, 47 (11.5%) HBsAg positive, and 33 (8.1%) HBV/HDV positive recipients. Recipient risk factors for baseline CKD were advanced age (P=0.044), raised levels of serum uric acid (P<0.0001), and insulin dependent DM (P=0.0034). Early post-transplant AKI was common (n=95); logistic regression analysis found that baseline serum creatinine was an independent predictor of early post-LT AKI (P=0.0154). According to our Cox proportional hazards model, recipient risk factors for de novo CKD included aging (P<0.0001), early post-transplant AKI (P=0.007), and baseline serum creatinine (P=0.0002). At the end of follow-up, there were 116 LT recipients with CKD - 109 (93.9%) and 7 (6.1%) had stage 3 and advanced CKD, respectively. Only two of them are undergoing long-term dialysis.

CONCLUSION

The incidence of CKD was high in our cohort of LT recipients, but only a slight decline in kidney function over time was recorded. Prevention of post-transplant AKI will improve kidney function in the long run. We need more studies to analyze the function of kidneys among LT recipients over extended follow-ups and their impact on mortality.

CKD in Recipients of Nonkidney Solid Organ Transplants: A Review

Chronic kidney disease (CKD) after solid organ transplant is a common clinical presentation, affecting 10% to 20% of liver, heart and lung transplant recipients and accounting for approximately 5% of the kidney transplant waiting list. The causes of CKD are different for different types of transplants and are not all, or even predominantly, due to calcineurin inhibitor toxicity, with significant heterogeneity particularly in liver transplant recipients. Many solid organ transplant recipients with advanced CKD benefit from kidney transplantation, but have a higher rate of death while waitlisted and higher mortality following transplant than the general kidney failure population. Recent organ allocation policies and proposals have attempted to address the appropriate identification and prioritization of candidates in need of a kidney transplant, either simultaneous with or following non-kidney transplant. Future research should focus on predictive factors for individuals identified at high risk for progression to kidney failure and death, and strategies to preserve kidney function and minimize the CKD burden in this unique patient population.

Acute kidney injury and chronic kidney disease after liver transplant: A retrospective observational study

BACKGROUND AND RATIONALE

Chronic kidney disease remains an important risk factor for morbidity and mortality among LT recipients, but its exact incidence and risk factors are still unclear.

MATERIAL AND METHODS

We carried out a retrospective cohort study of consecutive adults who underwent liver transplant (January 2009-December 2018) and were followed (at least 6 months) at our institution. CKD was defined following the Kidney Disease: Improving Global Outcomes (KDIGO) 2012 Clinical Practice Guidelines. Long-term kidney function was classified into 4 groups: no CKD (eGFR, ≥60mL/min/1.73m2), mild CKD (eGFR, 30-59mL/min/1.73m2), severe CKD (eGFR, 15-29mL/min/1.73m2), and end-stage renal disease (ESRD).

RESULTS

We enrolled 410 patients followed for 53.2±32.6 months. 39 had CKD at baseline, and 95 developed de novo CKD over the observation period. There were 184 (44.9%) anti-HCV positive, 47 (11.5%) HBsAg positive, and 33 (8.1%) HBV/HDV positive recipients. Recipient risk factors for baseline CKD were advanced age (P=0.044), raised levels of serum uric acid (P<0.0001), and insulin dependent DM (P=0.0034). Early post-transplant AKI was common (n=95); logistic regression analysis found that baseline serum creatinine was an independent predictor of early post-LT AKI (P=0.0154). According to our Cox proportional hazards model, recipient risk factors for de novo CKD included aging (P<0.0001), early post-transplant AKI (P=0.007), and baseline serum creatinine (P=0.0002). At the end of follow-up, there were 116 LT recipients with CKD - 109 (93.9%) and 7 (6.1%) had stage 3 and advanced CKD, respectively. Only two of them are undergoing long-term dialysis.

CONCLUSION

The incidence of CKD was high in our cohort of LT recipients, but only a slight decline in kidney function over time was recorded. Prevention of post-transplant AKI will improve kidney function in the long run. We need more studies to analyze the function of kidneys among LT recipients over extended follow-ups and their impact on mortality.

Treatment of Hypertension Because of Immunosuppressive Therapy After Solid Organ Transplantation-Pharmacological Approach

ABSTRACT

Solid organs transplantation procedures have been performed for more than half a century. Growing knowledge of immune response and development of new immunosuppressive regimens guarantee more and more successful outcomes. However, many of the applied drugs lead to cardiovascular complications, the most frequent of which is hypertension. This article describes epidemiology, pathogenetic mechanisms, and treatment of hypertension induced by immunosuppressive medication. The main impact is focused on drugs belonging to the following groups: calcineurin inhibitors, the inhibitors of the mammalian target of rapamycin, and glucocorticosteroids. We analyze the mechanism of action of the main hypertensive drugs and their influence on the reversing hypertonic action of the immunosuppressive agents. In the absence of current guidelines addressing this problem, this article is an attempt to fill the gap, helping clinicians to choose proper medication.

Blood Pressure in De Novo Heart Transplant Recipients Treated With Everolimus Compared With a Cyclosporine-based Regimen: Results From the Randomized SCHEDULE Trial

BACKGROUND

Systemic hypertension is prevalent in heart transplant recipients and has been partially attributed to treatment with calcineurin inhibitors (CNIs). SCandinavian HEart transplant De-novo stUdy with earLy calcineurin inhibitors avoidancE trial was the first randomized trial to study early withdrawal of CNIs in de novo heart transplant recipients, comparing an everolimus-based immunosuppressive regimen with conventional CNI-based treatment. As a prespecified secondary endpoint, blood pressure was repeatedly compared across treatment arms.

METHODS

The The SCandinavian HEart transplant De-novo stUdy with earLy calcineurin inhibitors avoidancE trial was a prospective, multicenter, randomized, controlled, parallel-group, open-label trial in de novo adult heart transplant recipients, undertaken at transplant centers in Scandinavia. Blood pressure was assessed with 24-hour ambulatory blood pressure monitoring up to 3 years after heart transplantation (HTx) in 83 patients.

RESULTS

Overall, systolic blood pressure fell with time, from 138 ± 15 mm Hg 2 weeks after HTx to 134 ± 11 mm Hg after 12 months and 132 ± 14 mm Hg after 36 months (P = 0.003). Diastolic blood pressure did not change over time. After 12 months, there was a numerically larger fall in systolic blood pressure in the everolimus arm (between-group difference 8 mm Hg; P = 0.053), and after 36 months, there was a significant between group difference of 13 mm Hg (P = 0.02) in favor of everolimus.

CONCLUSIONS

In this first, randomized trial with early CNI avoidance in de novo HTx recipients, we observed a modest fall in systolic blood pressure over the first 1 to 3 years after transplantation. The fall in systolic blood pressure was more pronounced in patients allocated to everolimus.

Intensive blood pressure control is associated with improved patient and graft survival after renal transplantation

Based on data of the SPRINT trial, American hypertension guidelines recently reduced the blood pressure goal from 140/90 mmHg to 130/80 mmHg for subjects with chronic kidney disease (CKD), whereas European guidelines recommend a systolic blood pressure (SBP) of 130-139 mmHg. The present analysis investigates whether a SBP < 130 mmHg is associated with an additional benefit in renal transplant recipients. We performed a retrospective analysis of 815 renal transplant recipients who were stratified according to mean office SBP values < 130 mmHg, 130-139 mmHg or ≥140 mmHg. Patient and graft survival was defined as composite endpoint, follow-up was limited to 120 months. Mean SBP of the follow-up was significantly associated with the composite endpoint (n = 218) with better survival for a SBP < 130 mmHg and 130-139 mmHg compared to ≥140 mmHg (p < 0.001). The differences in the combined endpoint remained significant in Cox regression analysis adjusted for age, gender and eGFR (p = 0.007, HR = 0.58, 95%CI = 0.41-0.53), but not for graft survival alone. Renal transplant recipients with SBP < 130 mmHg had a lower mortality than those with the conservative blood pressure goal <140 mmHg. These data suggest that the new AHA BP targets are safe for renal transplant recipients and - with all limitations of a retrospective analysis - might even be associated with improved outcome.