Impaired night time reduction in blood pressure is associated with cardiac hypertrophy, increased natriuretic hormone levels and left ventricular systolic and diastolic dysfunction

Abstract

An attenuated night time reduction in blood pressure (BP) may suggest hypertensive target organ damage and hence an unfavorable prognosis. We examined 75 hypertensive patients with left ventricular hypertrophy (LVH), 35 hypertensive patients with no LVH, and 23 normotensive subjects by 24-h ambulatory BP monitoring, echocardiography and circulating neurohormone levels. Mean (±SD) age was 55±8 ys, office BP 159±19/103±8, 147±13/97±6 and 119±10/79±7 mm Hg, and LV mass index 146±28, 99±14 and 90±15 g/m2, respectively. All were currently untreated and without coronary artery disease, systolic LV dysfunction or heart failure. There were close correlations between mean 24-h ambulatory and office BP (r=0.82 and 0.78 for systolic and diastolic, respectively, p<0.001), and mean 24-h ambulatory BP and LV mass index (r=0.59 and 0.60 for systolic and diastolic, respectively, p<0.001). The systolic white-coat effect (office BP minus day-time ambulatory BP) related weakly to LV mass index (r=0.18, p< 0.05). The night/day 24-h ambulatory BP ratio was greater in patients with LVH, as compared to no LVH and control subjects (systolic night/day ratio 0.88±0.07, 0.86±0.08 and 0.85±0.05, p<0.05; diastolic night/day ratio 0.83±0.07, 0.81±0.08 and 0.78±0.07, respectively, p<0.01). The night/day ratio related to LV mass index (systolic r=0.20, p<0.05, diastolic r=0.22, p<0.01). Non-dipping (i.e., mean arterial BP night/day ratio >0.9) was more common in both hypertensive groups than among controls (20 vs 5%). Compared to dippers, non-dippers had higher brain (6.1±7.5 vs 3.7±3.2 pmol/L, p<0.01) and atrial (14±3.4 vs 9.3±5.4 pmol/L, p<0.05) natriuretic peptide levels, lower LV ejection fraction (0.49±8 vs 0.57±9, p<0.01), lower E/A ratio (0.92±0.22 vs1.1±0.31, p< 0.01) and longer isovolumic relaxation time (118±24 vs 108±19 ms, p<0.05). In conclusion, an attenuated night time blood pressure reduction is associated with an increased LV mass and systolic and diastolic dysfunction, suggesting more advanced hypertensive cardiac organ damage. Thus, 24-h ambulatory BP monitoring may improve risk stratification.