Nighttime BP may be independent predictor of future CVD
Fluctuations in nighttime BP may represent a key predictor of future stroke, CAD and HF, according to a study published in Circulation.
“Our results showed the possibility that the riser pattern is important risk independent of 24-hour BP levels, even in the groups with well-controlled 24-hour BP levels. Some mechanism of riser pattern of nocturnal BP dipping status, which links to HF risk should be clarified,” Kazuomi Kario, MD, PhD, professor of cardiovascular medicine at Jichi Medical University in Tochigi, Japan, told Healio. “An intervention study to reduce nighttime BP level of less than 120 mm Hg will be needed.
“Many people suffer from HF after having stroke events or CAD,” Kario said in an interview. “Antihypertensive strategy targeting nighttime BP would be effective to reduce further CVD events, especially in patients with HF.”
For this prospective, observational study, researchers included 6,359 patients from Japan (mean age, 69 years; 48% men; mean follow-up, 4.5 years) with at least one CV risk factor (93.2% with hypertension) who were free of symptomatic CVD at baseline to evaluate the association between both nocturnal hypertension and nighttime BP dipping and incident CV events. All participants underwent 24-hour ambulatory BP monitoring at baseline and were followed up annually.
Increases in nighttime BP
Investigators observed that for every 20 mm Hg increase in nighttime systolic BP, patients experienced a 21% increase in risk for atherosclerotic CVD (HR = 1.21; 95% CI, 1.03-1.41) and a 36% increase in risk for HF (HR = 1.36; 95% CI, 1.08-1.71).
According to the analysis, each 20 mm Hg increase in daytime systolic BP was associated with an increased risk for ASCVD (22%; P = .048), but not total CVD (16%; P = .078).
Riser vs. dipper patterns for CVD prediction
Among these patients, those who experienced the riser pattern of nighttime BP experienced a significantly increased risk for both total CVD events (HR = 1.58; 95% CI, 1.13-2.21) and HF (HR = 2.53; 95% CI, 1.4-4.56).
“We found that the association between the riser pattern and total CVD events remained significant even after adjusting for 24-hour and daytime systolic BP, but the association disappeared after adjustment for nighttime systolic BP,” the researchers wrote. “This suggests that higher nighttime BP is more important than the riser pattern as a risk factor for total CVD.”
Moreover, the increased risk for HF associated with the riser nighttime BP pattern decreased after adjusting for nighttime and office systolic BP but remained high (HR = 2.23; 95% CI, 1.1-4.55). According to the researchers, this may indicate that a riser pattern for nighttime BP is more important than nighttime BP as a risk factor for HF.
There was also an elevated risk for HF among those with well-controlled systolic BP and a riser pattern (HR = 3.78; 95% CI, 1.61-8.89).
Additionally, investigators identified an elevated risk for stroke among patients with well-controlled 24-hour systolic BP and an extreme nighttime dipper pattern (HR = 2.3; 95% CI, 1.22-4.35).
“Results indicate that nighttime systolic blood pressure was a significant, independent risk factor for cardiovascular events,” Kario said in a press release. “The study highlights the importance of including nighttime blood pressure monitoring in patient management strategies and will hopefully encourage physicians to ensure that antihypertensive therapy is effectively lowering blood pressure throughout the 24-hour dosing period.”