Abnormal 24-hour blood pressure patterns in children after renal transplantation

Twenty-four hour blood pressure profile and left ventricular hypertrophy early after renal transplantation

BACKGROUND

Left ventricular hypertrophy is common in renal transplant patients but the factors influencing its development remain to be determined. The present investigation was conducted to study the effect of blood pressure load on the left ventricular mass of recently transplanted patients using 24-h ambulatory blood pressure monitoring (ABPM).

METHODS

We studied 30 renal transplant (RT) patients (36.1+/-13.7 years old, 11 males, 26 Whites, 4 diabetics, 15 under antihypertensive medication, 21 recipients of cadaver donors, and all treated with steroids, cyclosporin and azathioprine and with adequate (serum creatinine < 1.8 mg/100 ml) renal function). The median duration of dialysis treatment before transplant was 37 months, and the studies were performed during the first 40 days post-transplantation. Blood pressure was measured after a 15-min rest (casual blood pressure) and during a 24-h period with a SpaceLabs apparatus. Echocardiograms were obtained from all patients.

RESULTS

Mean left ventricular mass index (LVMI) was 153+/-44 g/m2; casual systolic and diastolic BP (mmHg) was 152+/-25 and 92+/-13, whereas systolic and diastolic 24-h BP was 133+/-12 and 85+/-8, respectively. The systolic sleeping BP/awake systolic BP (SSBP/ASBP) ratio was 0.94+/-0.07, and 73% of the patients did not show a significant (>10%) fall of systolic blood pressure during sleep. Multivariate analysis showed that awake systolic blood pressure was the only variable that independently influenced LVMI after adjusting for confounding factors (regression coefficient = 0.49, p = 0.01). Casual systolic and diastolic BP, sleeping systolic and diastolic blood pressure, 24-h heart rate, age, race, gender, smoking, body mass index, duration of dialysis, diabetes, antihypertensive and immunosuppressive drugs and levels of hematocrit, creatinine and serum lipids did not correlate with LVMI.

CONCLUSION

The data indicate that left ventricular hypertrophy during the early post-transplant period is mainly influenced by awake blood pressure load. They also suggest that ABPM may be more useful in the diagnosis and management of post-transplant hypertension than casual BP. The findings emphasize the importance of rigid blood pressure control in renal transplant recipients.

Short-term pediatric renal transplant survival: blood pressure and allograft function

Hypertension is prevalent after renal transplantation (Tx) and associated with graft failure in children and adults. However, the effect of blood pressure (BP) on short-term renal allograft function is uncertain. We assessed the associations among BP pretransplant, and 3 months and 1 yr post-transplant, and 1-yr post-transplant measured glomerular filtration rate (mGFR) in 61 children with a functioning graft. The GFR was determined using a single intravenous (i.v.) injection of Optiray 350(R). Data were collected between January 1994 and January 2000. The mean mGFR 1 yr after renal transplant was 63.6 +/- 19.9 mL/min/1.73 m2 in 26 live donor recipients and 50.8 +/- 23.3 mL/min/1.73 m2 in 35 cadaveric donors (p = 0.029). Correlation analysis showed significant negative associations of 1-yr mGFR with systolic blood pressure (SBP) and diastolic blood pressure (DBP) 3 months after renal Tx (r = - 0.58, p < 0.0001 and r = - 0.50, p < 0.0001, respectively), and with SBP (r = - 0.37, p = 0.003) and DBP (r = - 0.32, p = 0.01) 1 yr after renal Tx. Multi-variate regression analysis showed that the SBP 3 months after Tx (p < 0.001), number of acute rejections (p = 0.002), donor age (p = 0.02), and cold ischemia time (p = 0.03) were independent predictors for the 1-yr mGFR. These results indicate that a higher SBP in the first few months post-renal Tx is associated with decreased renal allograft function in children 1 yr post-Tx.

Ambulatory blood pressure measurements

Ambulatory blood pressure monitoring (ABPM) has emerged as a valuable clinical and research tool in the assessment of pediatric hypertension. Large databases of 24-hour blood pressure monitorings in healthy children are under development for establishing normal reference values analogous to the Task Force data for casual blood pressure. In the clinical setting, pediatric studies using ABPM to evaluate elevated blood pressure have shown that the prevalence of white coat hypertension in children is similar to that reported in adults. Furthermore, 24-hour blood pressure parameters are correlated with hypertensive end-organ injury such as left ventricular hypertrophy. ABPM has allowed detailed assessment of circadian blood pressure patterns that show early subtle abnormalities in some high-risk groups and normal patterns in other groups previously thought to be at high risk. These studies will assist in the practice of evidence-based medicine regarding pediatric hypertension that will improve the long-term care that pediatricians provide to their patients.