Dissertation committee:
Μελέτιος-Αθανάσιος Δημόπουλος, Καθηγητής, Ιατρική Σχολή, ΕΚΠΑ
Νικόλαος Ζακόπουλος, Καθηγητής, Ιατρική Σχολή, ΕΚΠΑ, Επιβλέπων
Δημήτριος Βλαχάκος Καθηγητης, Ιατρική Σχολή, ΕΚΠΑ
Ευστάθιος Μανιός, Αναπληρωτης Καθηγητης, Ιατρική Σχολή, ΕΚΠΑ
Κίμων Σταματελόπουλος, Αναπληρωτης Καθηγητης, Ιατρική Σχολή, ΕΚΠΑ
Ευστάθιος Καστρίτης, Αναπληρωτης Καθηγητης, Ιατρική Σχολή, ΕΚΠΑ
Μαρία Γαβριατοπούλου, Επικουρη Καθηγητρια, Ιατρική Σχολή, ΕΚΠΑ
Summary:
Background
The clinical value of average blood pressure (BP) levels for the management and treatment of arterial hypertension has been well established. However, over recent decades, there has been increasing interest in the additional prognostic value of BP variability (BPV) in addition to the impact of mean BP levels. Evidence from observational and interventional studies has clearly demonstrated that increased BPV has been associated with the development and progression of target organ damage (TOD) as well as with an increased risk of cardiovascular morbidity and mortality in hypertensive patients beyond the impact of the average BP level alone. Nevertheless, in patients with chronic kidney disease (CKD), there is limited evidence regarding the impact of BPV on TOD. A multicenter study of 1173 CKD patients illustrated that ambulatory BPV was associated with left ventricular hypertrophy, independent of the 24-h mean BP values. The aim of our study was to compare the association of home and ambulatory BPV indices with the left ventricular mass index (LVMI),the left atrium diamteter (LA), intima-media thickness og carotid arteries (MCCA), pulse wave velocity (PWV), augmentation index (AI), ankle-branchial index (ABI) in CKD patients.
Methods
All patients underwent office BP measure- ments and 24-h ambulatory BP monitoring. A total of 137 patients fulfilled the following inclusion criteria: (1) an estimated glomerular filtration rate (eGFR) between 15 and 60 ml/min/1.73 m2 in two visits with an interval of 3 months, (2) abnormal office (systolic BP (SBP) ≥ 140 mmHg and/or dia- stolic BP (DBP) ≥ 90 mmHg) and 24-h ambulatory BP (24-h SBP ≥ 130 mmHg and/or 24-h DBP ≥ 80 mmHg) values or antihypertensive treatment, (3) no history of electrocardio- graphic evidence of atrial fibrillation, and (4) at least three valid BP measurements per hour from 24-h ambulatory BP monitoring. This cohort underwent further evaluation with 7-day home BP monitoring and echocardiographic measure- ments of the LVMI according to a prespecified protocol.
Renal function was assessed using the Chronic Kidney Disease Epidemiology Collaboration equation, which cal- culates the eGFR from the following formula: eGFR = 141 × min(Scr/κ,1)α × max(Scr/κ, 1)−1.209 × 0.993Age × 1.018 [if female] × 1.159 [if black]. Risk factors such as diabetes mellitus, hypercholesterolemia, smoking, and body mass index were recorded.
Results
Our study population consisted of 137 patients with CKD. Pearson’s correlation coefficient was used to investigate the correlations between the BPV indices and the LVMI. Among all home BPV indices included in our analysis, only the day-to-day systolic SD was sig- nificantly correlated with the LVMI (r = 0.180, p = 0.044). Regarding the ambulatory BPV indices, the 24-h (r = 0.341, p < 0.001) and daytime TR of SBP variation (r = 0.331, p = 0.001) were significantly associated with the LVMI. In terms of average BP values, only the office SBP (r = 0.230, p = 0.010), home SBP (r = 0.238, p = 0.007),and 24-h SBP (r = 0.301, p = 0.001) were significantly correlated with the LVMI. The factors associated with the LVMI were determined by means of univariate and multivariate linear regression models. The office SBP, 24-h SBP, TR of 24-h SBP variation, day-to-day home systolic SD, eGFR, and gender were included in the multivariate model. Home SBP was also significantly associated with the LVMI; however, it was not included in the multivariate model as it was collinear with another variable (highly correlated with 24-h SBP, r > 0.6). The multivariate linear regression analyses showed a significant and independent association of the LVMI with the TR of the 24-h SBP variation (B = 9.204, 95% CI: 1.735–16.672; p = 0.016). A 0.1-mmHg/min increase in the 24-h rate of SBP variation was associated with an increment of 9.204 g/m2 in the LVMI independent of BP and other vascular risk factors. The predicted model accounted jointly for 43.4% of the variation in the LVMI (R2 = 0.188).
Conclusion
The results of our study showed that ambulatory BPV and, more specifically, the TR of SBP variation were significantly and positively associated with the LVMI in patients with CKD, even after adjustment for BP levels and vascular risk factors. In contrast, home BPV failed to demonstrate such an association. In conclusion, our study demonstrated that short-term BPV, but not mid-term BPV, was associated with the LVMI in CKD patients, independent of BP levels and other vas- cular risk factors. Moreover, among the three ambulatory BPV indices included in our analysis, only the TR of SBP variation was significantly associated with LVMI. Our findings support that different types and indices of BPV have different prognostic significance.
