Impact of diltiazem administration and cyclosporine levels on the incidence of acute rejection in heart transplant patients

Management of hypertension in heart transplant recipients: an ongoing conundrum

PURPOSE OF REVIEW

Hypertension remains one of the most common clinical problems leading to significant posttransplant complications. This study reviews the pathophysiology of hypertension in the postcardiac transplant phase and provides an update on currently available antihypertensive therapies for heart transplant patients.

RECENT FINDINGS

The true prevalence of hypertension in the heart transplant population remains unknown. Effective blood pressure (BP) control is key to prevent left ventricular remodeling, diastolic dysfunction and stroke. Calcium channel blockers (CCBs) are the most commonly and preferred agents in the early posttransplant phase and may have renal protective effects. Angiotensin-converting enzyme inhibitors (ACEIs), angiotensin receptor blockers (ARBs) can all be used as second line antihypertensive agents and may have a role in preventing other long-term complications such as calcineurin-inhibitor induced nephropathy. Although more data are needed, sodium-glucose co-transporter 2 inhibitors (SGLT2i) appeared to be well tolerated and could be considered especially in the presence of type diabetes and chronic kidney disease. Conversely, angiotensin receptor-neprilysin inhibition (ARNI) have not been studied in the heart transplant population therefore cannot be recommended at this time.

SUMMARY

Hypertension is very common after heart transplant. Early steroid wean and traditional risk factor modification play an important part in the management of post-heart transplant hypertension. CCB, ACEI, ARB are the preferred antihypertensive agents to improve postcardiac transplant complications. Novel therapies such as SGLT2i appear well tolerated and may have benefits in both BP and glycemic control in heart transplant; however, larger trials are needed.

Should we consider heart rate reduction in cardiac transplant recipients?

Increased resting heart rate is an independent modifiable risk factor for the development of cardiovascular disease. Numerous studies have demonstrated improved clinical outcomes with heart rate reduction in patients with coronary artery disease and heart failure, but its role in transplanted hearts is not yet established. Sinus tachycardia is more common in heart transplant recipients due to graft denervation. Although a large number of studies have recognized increased heart rate as a predictor of native coronary artery atherosclerosis and overall cardiac mortality, contradicting results have been observed in heart transplant recipients. There is no clear consensus about what the normal range of heart rate should be following heart transplantation. The aim of this article was to review the literature to evaluate whether heart rate reduction should be considered in heart transplant recipients.

Hypertension after pediatric cardiac transplantation: detection, etiology, implications and management

While it may rescue children with end-stage heart failure from impending catastrophe, cardiac transplantation leaves 50-70% of pediatric recipients with new-onset hypertension. Given the unique vulnerability of the heart and kidneys in these children, we can expect long-term uncontrolled hypertension to shorten both graft and patient survival. In this review we discuss the multi-factorial etiology of post-transplant hypertension, highlighting current uncertainties and emphasizing mechanisms specific to cardiac recipients. We consider the optimal means of monitoring BP and in particular, the advantages of 24 h-ABP over intermittent clinic measurements. We also review BP treatment after cardiac transplantation, drawing attention to specific cautions appropriate when prescribing antihypertensive agents in these circumstances.

Combination use of immune complexes and a Ca2(+) channel blocker azelnidipine enhances interleukin-12 p40 secretion without T helper type 17 cytokine secretion in human monocyte-derived dendritic cells

Immune complexes (ICs) improve the capacity of priming specific CD8(+) cytotoxic T cell responses of dendritic cells (DCs). ICs induce phosphorylation of mitogen-activated protein kinases (MAPK) and calcium influx, although the precise regulating mechanism still remains unclear. In the present study, we investigated the effect of a Ca2(+) channel blocker on the phosphorylation of p38 MAPK and extracellular signal-regulated kinase (ERK) in immature monocyte-derived DCs stimulated with lipopolysaccharide (LPS) or LPS-ICs, and the production of interleukin (IL)-12 family members (p40, p70, IL-23), T helper type 17 (Th17) cytokines (IL-6 and IL-23), tumour necrosis factor (TNF)-alpha and IL-10 were also investigated. In comparison with LPS stimulation, LPS-ICs stimulation enhanced p38 MAPK phosphorylation significantly, which was associated with an increase in IL-12 p40 monomer/homodimer secretion. LPS-ICs also enhanced TNF-alpha and IL-6 secretion, but suppressed IL-23 secretion. The use of azelnidipine (Aze), a long-acting L-type Ca2(+) channel blocker with a high lipid solubility, suppressed p38 MAPK phosphorylation stimulated with LPS or LPS-ICs, but surprisingly enhanced IL-12 p40 monomer/homodimer secretion stimulated with LPS-ICs. This IL-12 p40 secretion-enhancing effect was not accompanied by IL-10 or IL-23 production, but was associated with ERK phosphorylation. The use of Aze did not affect IL-12 p70 production. These results suggest that the use of Aze enhances ICs-mediated IL-12 p40 secretion without additional IL-23 secretion. Therefore, the use of Aze and ICs could be a new therapeutic approach to immunomolecular therapy, as it does not cause Th17 differentiation which induces autoimmunity or reduces anti-tumour immunity.

Use of calcium channel blockers and angiotensin-converting enzyme inhibitors after cardiac transplantation

PURPOSE OF REVIEW

Hypertension, dyslipidemia, and diabetes are very common problems following heart transplantation and may contribute to the development and progression of graft coronary artery disease. This article reviews current data on clinical use of angiotensin-converting enzyme inhibitors and calcium channel blockers in patients who have had heart transplants.

RECENT FINDINGS

Angiotensin-converting enzyme inhibitors and calcium channel blockers are established therapy for patients with cardiovascular disease. Use of these medications correlates with decreasing cardiovascular morbidity and mortality.

SUMMARY

After heart transplantation, hypertension associated with calcineurin inhibitors can be managed effectively with antihypertensive therapy, but it may require use of more than one antihypertensive agent. Calcium channel blockers and angiotensin-converting enzyme inhibitors have been associated with improved outcome measures in graft coronary artery disease.

Acute rejection after heart transplantation

Acute rejection (AR) seems to be less common with current immunosuppressive strategies; however, it remains a major cause of morbidity and mortality in the first year following heart transplantation. Despite great interest in noninvasive methods for detecting rejection, the endomyocardial biopsy remains the standard method for AR identification and, recently, the cardiac biopsy grading system has been reviewed. Moreover, the availability of several immunosuppressive drug combinations has generated confusion in the minds of clinicians. This review will focus on recently published studies that are related to the clinical impact of AR, combination regimens of chronic maintenance immunosuppression and specific therapeutic options for treating AR.

Is biopsy-proven cellular rejection an important clinical consideration in heart transplantation?

PURPOSE OF REVIEW

Immunosuppression strategies to prevent allograft rejection represent the cornerstone of long-term survival after heart transplantation. Endomyocardial biopsy has defined rejection in clinical cardiac transplantation and established a threshold for therapy. With the development of more effective immunosuppression modalities and the asymptomatic nature of most histologic rejection episodes, controversy exists regarding the need to augment immunosuppression based purely on histologic findings.

RECENT FINDINGS

The frequency of histologic rejection has declined with current immunosuppression. Resolution of lower grades of histologic rejection without treatment is the norm in both pediatric and adult heart transplant studies. Recurrent rejection episodes have been linked to the subsequent development of allograft coronary artery disease, and late rejection (even if asymptomatic) is associated with decreased survival in pediatric heart transplant recipients. Black race is a risk factor for recurrent rejection and reduced survival after late cellular rejection. Apoptosis of inflammatory cells is more evident during and after histologic rejection treated with corticosteroids. Despite numerous noninvasive modalities evaluated for the detection of rejection, to date noninvasive methods cannot reliably predict histologic rejection.

SUMMARY

Histologic rejection appears less common with current immunosuppressive strategies, and controversy exists about the need to treat asymptomatic rejection. It remains unproven whether non-treatment of moderate or greater rejection (>/=3A) increases the likelihood of recurrent rejection, which if present, may increase the risk of allograft coronary disease and/or reduced long-term survival.

Inhibitors of Calcineurin

Before the early 1980s, patient and allograft survival for solid organ transplant recipients was dismal. By 1983, the first calcineurin blocker, cyclosporine (Sandimmun), had been introduced, and outcomes were dramatically improved. However, cyclosporine macroemulsion had suboptimal pharmacokinetics, significant drug interactions, and several adverse effects, including nephrotoxicity, neurotoxicity, hyperlipidemia, and hypertension. Recent advances with cyclosporine include the introduction of modified dosage formulations: Neoral, a microemulsion, and several generic microemulsion products. The potent second-generation calcineurin blocker tacrolimus (Prograf) was introduced in 1994 and has become the drug of choice for several types of transplant recipients. Although tacrolimus has improved pharmacokinetics and therapeutic drugmonitoring parameters, it has adverse effects such as nephrotoxicity, neurotoxicity, and diabetes. Thus, current immunosuppressive regimens implementing calcineurin blockers often involve additional immunosuppressive agents to “spare” the use of these agents, minimizing their adverse effects. This article reviews the mechanisms of action, pharmacokinetics, clinical use, therapeutic drug monitoring, drug interactions, adverse effects, and dosing of cyclosporine and tacrolimus in solid organ transplant recipients.