Ambulatory blood pressure monitoring in solid organ transplantation

New onset hypertension after transplantation

It has been reported that up to 90% of organ transplant recipients have suboptimal blood pressure control. Uncontrolled hypertension is a well-known culprit of cardiovascular and overall morbidity and mortality. In addition, rigorous control of hypertension after organ transplantation is a crucial factor in prolonging graft survival. Nevertheless, hypertension after organ transplantation encompasses a broader range of causes than those identified in non-organ transplant patients. Hence, specific management awareness of those factors is mandated. An in-depth understanding of hypertension after organ transplantation remains a debatable issue that necessitates further clarification. This article provides a comprehensive review of the prevalence, risk factors, etiology, complications, prevention, and management of hypertension after organ transplantation.

Blood Pressure and Living Kidney Donors: A Clinical Perspective

Elevated blood pressure (BP), or “hypertension,” has been one of the main exclusion criteria for living kidney donation, as it is a risk factor for renal and cardiovascular disease. The effect of elevated BP in living kidney donors is not well studied or understood. The most current living kidney donation guidelines state that donors with a BP >140/90 mm Hg with 1–2 antihypertensive medications or evidence of end-organ damage should be excluded from living kidney donation. Yet, the definitions of “hypertension” have changed with the release of the American Heart Association (AHA)/American College of Cardiology (ACC) clinical practice guidelines suggesting that 120–129 mm Hg is elevated BP and Stage 1 hypertension is 130 mm Hg. However, the kidney function (in terms of estimated GFR) of “hypertensive” living kidney donors does not fare significantly worse postdonation compared with that of “normotensive” donors. In addition, even though living kidney donation itself is not considered to be a risk factor for developing hypertension, there exist certain risk factors (African American or Hispanic descent, obesity, age) that may increase the risk of living kidney donors developing elevated BP postdonation. The choice of BP targets and medications needs to be carefully individualized. In general, a BP <130/80 mm Hg is needed, along with lifestyle modifications.

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.

Diagnostic Performance of Blood Pressure Measurement Modalities in Living Kidney Donor Candidates

BACKGROUND AND OBJECTIVES

Precise BP measurement to exclude hypertension is critical in evaluating potential living kidney donors. Ambulatory BP monitoring is considered the gold standard method for diagnosing hypertension, but it is cumbersome to perform. We sought to determine whether lower BP cutoffs using office and automated BP would reduce the rate of missed hypertension in potential living donors.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We measured BP in 578 prospective donors using three modalities: (1) single office BP, (2) office automated BP (average of five consecutive automated readings separated by 1 minute), and (3) ambulatory BP. Daytime ambulatory BP was considered the gold standard for diagnosing hypertension. We assessed both the Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC-7) and the American College of Cardiology/American Heart Association (ACC/AHA) definitions of hypertension in the cohort. Empirical thresholds of office BP and automated BP for the detection of ambulatory BP-diagnosed hypertension were derived using Youden index, which maximizes the sum of sensitivity and specificity and gives equal weight to false positive and false negative values.

RESULTS

Hypertension was diagnosed in 90 (16%) prospective donors by JNC-7 criteria and 198 (34%) prospective donors by ACC/AHA criteria. Masked hypertension was found in 3% of the total cohort by JNC-7 using the combination of office or automated BP, and it was seen in 24% by ACC/AHA guidelines. Using Youden index, cutoffs were derived for both office and automated BP using JNC-7 (<123/82 and <120/78 mm Hg) and ACC/AHA (<119/79 and <116/76 mm Hg) definitions. Using these lower cutoffs, the sensitivity for detecting hypertension improved from 79% to 87% for JNC-7 and from 32% to 87% by ACC/AHA definition, with negative predictive values of 95% and 87%, respectively. Missed (masked) hypertension was reduced to 2% and 4% of the entire cohort by JNC-7and ACC/AHA, respectively.

CONCLUSIONS

The prevalence of hypertension was higher in living donor candidates using ACC/AHA compared JNC-7 definitions. Lower BP cutoffs in the clinic improved sensitivity and led to a low overall prevalence of missed hypertension in prospective living kidney donors.

Managing Cardiovascular Risk in the Post Solid Organ Transplant Recipient

Solid organ transplantation is an effective treatment for patients with end-stage organ disease. The prevalence of cardiovascular diseases (CVD) has increased in recipients. CVD remains a leading cause of mortality among recipients with functioning grafts. The pathophysiology of CVD recipients is a complex interplay between preexisting risk factors, metabolic sequelae of immunosuppressive agents, infection, and rejection. Risk modification must be weighed against the risk of mortality owing to rejection or infection. Aggressive risk stratification and modification before and after transplantation and tailoring immunosuppressive regimens are essential to prevent complications and improve short-term and long-term mortality and graft survival.

Comparison of office, home, and ambulatory blood pressure in heart transplant recipients

BACKGROUND

The purpose of this study was to prospectively evaluate the relationship between office, home, and ambulatory blood pressure (BP) in heart transplant recipients.

METHODS AND RESULTS

The study enrolled 30 adults ≥ 6 months after heart transplantation. Morning seated office BP was measured with the use of an automatic device at 3 outpatient visits. Seated home BP was measured in the morning and evening for 5 consecutive days. Ambulatory BP was measured over 24 hours with the use of a Spacelabs monitor. The strongest correlation was observed between home and 24-hour ambulatory BP (r = 0.79 systolic; r = 0.72 diastolic). Office and home systolic BPs were significantly lower than daytime ambulatory BP (office, -3.7 mm Hg, P = .009; home, -2.6 mm Hg, P = .05). Ambulatory monitoring identified more participants with BP above hypertensive limits than did office or home measurements (63%, 50%, and 13%, respectively; P = .003). Ambulatory monitoring also revealed high BP loads, abnormal nocturnal BP patterns (eg, 30% nondippers), and a high percentage of masked hypertension (37% home, 50% ambulatory).

CONCLUSIONS

Office and home BP monitoring are acceptable but may underestimate BP burden in heart transplant recipients. Additional studies are needed to determine which BP method is superior for the management of hypertension and associated outcomes after heart transplantation.

Hypertension after kidney transplantation: a pathophysiologic approach

Post-transplant hypertension is associated with decreased graft and patient survival and cardiovascular morbidity. Unfortunately, post-transplant hypertension is often poorly controlled. Important risk factors include immunosuppressive medications, complications of the transplant surgery, delayed graft function, rejection, and donor and recipient risk factors. The effects of immunosuppressive medications are multifactorial including increased vascular and sympathetic tone and salt and fluid retention. The immunosuppressive agents most commonly associated with hypertension are glucocorticoids and calcineurin inhibitors. Drug therapy for hypertension should be based on the comorbidities and pathophysiology. Evidence-based approaches to defining and treating hypertension in renal transplant recipients are predominantly extrapolated from large-scale studies performed in the general population. Thus, there continues to be a need for larger studies examining the pathophysiology, diagnosis and treatment of hypertension in renal transplant recipients.

Blood pressure measurements, blood pressure variability and endothelial function in renal transplant recipients

BACKGROUND/AIMS

Hypertension is an important cardiovascular risk factor in renal transplant recipients. Elevated blood pressure variability (BPV) during 24-h ambulatory blood pressure monitoring (ABPM) is associated with increased risk of target organ damage and cardiovascular events, independent of mean blood pressure levels. We aimed to evaluate the relationship between endothelial function, blood pressure levels obtained by various measurement methods, and BPV in renal transplant recipients.

METHODS

In total, 73 hypertensive renal transplant recipients were included in the study. Office blood pressure measurements, central blood pressure measurements, home blood pressure measurements and 24-h ABPM were obtained from the subjects. BPV was calculated using the average real variability index. All patients underwent brachial flow-mediated vasodilatation tests. Predictive values of blood pressures obtained by different measurement techniques and BPV on endothelial functions were investigated.

RESULTS

Endothelial dysfunction was present in 68.5% of the patients. No difference was found between the group with and without endothelial dysfunction with regard to office systolic or diastolic blood pressure, central blood pressure or home systolic blood pressure. In the group with endothelial dysfunction, 24-h ambulatory systolic blood pressure and night-time ambulatory systolic blood pressure were higher. In patients with endothelial dysfunction, the 24-h systolic, diastolic and mean BPV were all higher. There was also a negative correlation between the percentage of flow-mediated vasodilatation with 24-h mean and systolic BPV.

CONCLUSION

Patients with endothelial dysfunction had significantly higher ambulatory blood pressure values and higher BPV. There was a significant negative correlation between endothelial function and BPV.

Hypertension: The Neglected Complication of Transplantation

Arterial hypertension and transplantation are closely linked, and its association may promote impaired graft and overall survival. Since the introduction of calcineurin inhibitors, it is observed in 50–80% of transplanted patients. However, many pathophysiological mechanisms are involved in its genesis. In this review, we intend to provide an updated overview of these mechanisms, dealing with the causes common to all kinds of transplantation and emphasizing special cases with distinct features, and to give a perspective on the pharmacological approach, in order to help clinicians in the management of this frequent complication.