Noninvasive markers of arterial stiffness and renal outcomes in patients with chronic kidney disease

Abstract

Our study aimed to explore the intercorrelations of brachial-ankle pulse wave velocity (baPWV), ankle-brachial index (ABI), ambulatory arterial stiffness index (AASI), 24-hour mean pulse pressure (24-h PP), and augmentation index (AIx, AIx@75, the AIx standardized to a heart rate of 75) and compare the effectiveness of these markers for predicting renal outcomes. A total of 117 patients with chronic kidney disease (CKD) who received noninvasive arterial stiffness examinations were enrolled. We used correlation analysis and linear regression to explore the correlations between these five arterial stiffness markers and the Cox proportional hazards model and receiver operator characteristic (ROC) curve to assess the associations of markers with kidney disease outcomes. The median (interquartile range) of age and eGFR were 61 (49-65) years and 50.5 (35.5-84.1) ml/min/1.73 m² , respectively. In Pearson correlation analysis, baPWV was significantly associated with 24-h PP (r = .531, p < .001), AIx@75 (r = .306, p < .001). Additionally, 24-h PP was associated with AASI (r = .507, p < .001) and AIx@75 (r = .217, p = .019). During follow-up for a median of 25 months, 26.5% (n = 31) of patients had a composite outcome; of these, 10 initiated dialysis, 17 had 40% eGFR loss, and 4 died. Increased AASI, 24-h PP, and baPWV were associated with poor renal outcomes in a univariate Cox analysis. After adjusting for age, sex, MAP, eGFR, and 24 hours proteinuria, 1-SD increase in AASI and 24-h PP was associated with renal outcomes. The ROC analysis yielded the largest area under the curve (AUC) of 0.727 (95% CI: 0.624 to 0.831; p < .001) for 24 -h PP. When the Youden's index was at its maximum, the 24-h PP value was 52 mmHg. In conclusion, 24-h PP, baPWV, and AIx@75 were linked well to one another. Arterial stiffness is a target for delaying the decline in kidney function. The use of 24-h PP as an arterial stiffness marker should be valued in CKD clinical practice.

Keywords: arterial stiffness; chronic kidney disease; prognosis.

FIGURE 1

Correlations between markers of arterial stiffness. A for baPWV versus AASI; B for baPWV versus 24‐h PP; C for baPWV versus ABI; D for baPWV versus AIx@75; E for AASI versus 24‐h PP; F for AASI versus AIx@75; G for AASI versus ABI; H for 24‐h PP  versus AIx@75; I for 24‐h  PP versus ABI; J for AIx@75 versus ABI. AASI, ambulatory arterial stiffness index; AIx@75, augmentation index standardized to a heart rate of 75; 24‐h  PP, 24‐hour mean pulse pressure; baPWV, brachial‐ankle pulse wave velocity; ABI, ankle‐brachial index

FIGURE 2

Areas under the ROC curve describing the ability of arterial stiffness markers to predict renal outcomes. Letter a for AASI; b for 24‐h  PP; c for baPWV; d for ABI; e for AIx@75