Hypertension two years after renal transplantation: causes and consequences

Hypertension after renal transplantation

Hypertension is a common and serious complication after renal transplantation. It is an important risk factor for graft loss and morbidity and mortality of transplanted children. The etiology of posttransplant hypertension is multifactorial: native kidneys, immunosuppressive therapy, renal-graft artery stenosis, and chronic allograft nephropathy are the most common causes. Blood pressure (BP) in transplanted children should be measured not only by casual BP (CBP) measurement but also regularly by ambulatory BP monitoring (ABPM). The prevalence of posttransplant hypertension ranges between 60% and 90% depending on the method of BP measurement and definition. Left ventricular hypertrophy is a frequent type of end-organ damage in hypertensive children after transplantation (50-80%). All classes of antihypertensive drugs can be used in the treatment of posttransplant hypertension. Hypertension control in transplanted children is poor; only 20-50% of treated children reach normal BP. The reason for this poor control seems to be inadequate antihypertensive therapy, which can be improved by increasing the number of antihypertensive drugs. Improved hypertension control leads to improved long-term graft and patient survival in adults. In children, there is a great potential for antihypertensive treatment that could also result in improved graft and patient survival.

Effect of immunosuppressive agents on long-term survival of renal transplant recipients: focus on the cardiovascular risk

In the control of acute rejection, attention is being focused more and more on the long-term adverse effects of the immunosuppressive agents used. Since cardiovascular disease is the main cause of death in renal transplant recipients, optimal control of cardiovascular risk factors is essential in the long-term management of these patients. Unfortunately, several commonly used immunosuppressive drugs interfere with the cardiovascular system. In this review, the cardiovascular adverse effects of the immunosuppressive agents currently used for maintenance immunosuppression are thoroughly discussed. Optimising immunosuppression means finding a balance between efficacy and safety. Corticosteroids induce endothelial dysfunction, hypertension, hyperlipidaemia and diabetes mellitus, and impair fibrinolysis. The use of corticosteroids in transplant recipients is undesirable, not only because of their cardiovascular effects, but also because they induce such adverse effects as osteoporosis, obesity, and atrophy of the skin and vessel wall. Calcineurin inhibitors are the most powerful agents for maintenance immunosuppression. The calcineurin inhibitor ciclosporin (cyclosporine) not only induces these same adverse effects as corticosteroids but is also nephrotoxic. Tacrolimus has a more favourable cardiovascular risk profile than ciclosporin and is also less nephrotoxic. It has little or no effect on blood pressure and serum lipids; however, its diabetogenic effect is more prominent in the period immediately following transplantation, although at maintenance dosages, the diabetogenic effect appears to be comparable to that of ciclosporin. The diabetogenic effect of tacrolimus can be managed by reducing the dose of tacrolimus and early corticosteroid withdrawal. The effect of tacrolimus on endothelial function has not been completely elucidated. The proliferation inhibitors azathioprine and mycophenolate mofetil (MMF) have little effect on the cardiovascular system. Yet, indirectly, by inducing anaemia, they may lead to left ventricular hypertrophy. MMF is an attractive alternative to azathioprine because of its higher potency and possibly lower risk of malignancies. Sirolimus also induces anaemia, but may be promising because of its antiproliferative features. Whether the hyperlipidaemia induced by sirolimus counteracts its beneficial effects is, as yet, unknown. It may be combined with MMF, however, initial attempts resulted in severe mouth ulcers.

A prospective study of the physician effect on blood pressure in renal-transplant recipients

BACKGROUND

Physician presence results in elevated blood pressure (BP) in the general population. The determinants of this phenomenon in renal-transplant recipients are not known.

METHODS

We prospectively evaluated BP changes with physician presence in 231 stable adults with graft survival > or =1 year. A nurse measured timed sitting BP by Korotkoff phase I and V sounds before physician entry, during physician presence and upon exit. The haemoglobin, creatinine, weight, immunosuppressive drug dosage and/or level, and anti-hypertensive medication profile were recorded. Paired Student's t-test with Bonferroni correction and multiple linear regression analysis were used to examine BP changes. Characteristics of patients with change in mean arterial BP > or =+10 mmHg (n=55, "high") were compared with those with change < or =+5 mmHg (n=132, "low") by chi-square or Wilcoxon rank sum test as appropriate. A group of 100 recipients served as controls in whom BP was measured thrice without physician presence on any occasion. A multivariate analysis was performed for the combined groups controlling for physician entry as a predictor variable.

RESULTS

In the study group, systolic BP (mean+/-SE) rose by 4.2+/-0.8, diastolic BP by 3.5+/-0.5 and mean arterial BP by 3.5+/-0.5 mmHg in physician presence. The BP returned to baseline with exit (P<0.001 for each). Higher haemoglobin and creatinine demonstrated a trend towards influencing the physician-induced rise in diastolic BP. The "high" sub-group demonstrated a shorter time to the second BP measurement in physician presence (P=0.03) and a trend towards morning measurements (P=0.08). In the control group, systolic BP declined by 3.2+/-0.9 mmHg from the first to the second measurement, with a further decline of 2.4+/-0.6 mmHg from the second to third measurements. Diastolic BP did not change. In the combined multivariate analysis, physician entry was an independent predictor of BP change (P=0.0001).

CONCLUSIONS

Renal-transplant recipients demonstrate a significant physician effect on BP despite adequate experience with post-transplant clinic visits and BP-altering medication. This population deserves further evaluation through ambulatory BP monitoring.

Recommendations for the outpatient surveillance of renal transplant recipients. American Society of Transplantation

Many complications after renal transplantation can be prevented if they are detected early. Guidelines have been developed for the prevention of diseases in the general population, but there are no comprehensive guidelines for the prevention of diseases and complications after renal transplantation. Therefore, the Clinical Practice Guidelines Committee of the American Society of Transplantation developed these guidelines to help physicians and other health care workers provide optimal care for renal transplant recipients. The guidelines are also intended to indirectly help patients receive the access to care that they need to ensure long-term allograft survival, by attempting to systematically define what that care encompasses. The guidelines are applicable to all adult and pediatric renal transplant recipients, and they cover the outpatient screening for and prevention of diseases and complications that commonly occur after renal transplantation. They do not cover the diagnosis and treatment of diseases and complications after they become manifest, and they do not cover the pretransplant evaluation of renal transplant candidates. The guidelines are comprehensive, but they do not pretend to cover every aspect of care. As much as possible, the guidelines are evidence-based, and each recommendation has been given a subjective grade to indicate the strength of evidence that supports the recommendation. It is hoped that these guidelines will provide a framework for additional discussion and research that will improve the care of renal transplant recipients.