Long-Term Exposure to Elevated BP Associated With AS and AR

Researchers have observed a significant association between higher systolic blood pressure and pulse pressure levels and an increased risk of aortic valve disease and incident aortic stenosis and regurgitation, according to a recent study published in the European Heart Journal.

Previous studies have found positive associations between hypertension and the risk of aortic stenosis or aortic regurgitation; however, no analysis has reported the association across the complete range of blood pressure levels (systolic, diastolic, and pulse pressure). Authors of this large cohort study sought to investigate whether elevated blood pressure is a risk factor for aortic valve stenosis or aortic regurgitation.

The study cohort included 5,392,183 patients living the UK with no known cardiovascular disease or aortic valve disease at baseline who were followed for a median of 9.2 years. Patient health data was extracted from the UK Clinical Practice Research Datalink between January 1, 1990, and December 31, 2015. Individuals with prior diagnosis of cardiovascular disease, aortic stenosis, or aortic regurgitation at baseline were excluded from the study.

Primary outcomes were reports of incident aortic stenosis or regurgitation, and the primary exposure was systolic blood pressure, which researchers analyzed as a categorical variable. Subgroup analyses also tested systolic blood pressure, diastolic blood pressure, and pulse pressure as continuous variables with 20-mmHg, 10-mmHg, and 15-mmHg increments, respectively. The authors used multivariate Cox regression models to determine the relationship between blood pressure and risk of incident aortic stenosis and regurgitation.

Of the 5.4 million patients, 20,680 (0.38%) were diagnosed with aortic valve stenosis and 6440 (0.12%) patients with aortic regurgitation. The results showed a continuous relationship between systolic blood pressure the risk of aortic valve stenosis and regurgitation: Every 20-mmHg increment in systolic blood pressure was associated with 41% higher risk of aortic stenosis (hazard ratio [HR], 1.41; 95% CI, 1.38-1.45) and 38% higher risk of aortic regurgitation (HR, 1.38; 95% CI, 1.31-1.45).

Proportional increases in risk were consistent throughout the range of systolic blood pressure when systolic blood pressure was analyzed as a categorical variable. For diastolic blood pressure, each 10-mmHg increment was associated with 24% higher risk of aortic stenosis (HR, 1.24; 95% CI, 1.19-1.29) but not aortic regurgitation (HR, 1.04; 95% CI, 0.97-1.11).

In regard to pulse pressure, each 15-mmHg increment was associated with 46% higher risk of aortic valve stenosis (HR, 1.46; 95% CI, 1.42-1.50) and 53% higher risk of aortic regurgitation (HR, 1.53; 95% CI, 1.45-1.62).

While these associations were stronger in younger patients, other variables, such as gender and body mass index, did not influence the relationship between blood pressure and aortic outcomes.

Limitations of the study included the observational nature of the study. The investigators also did not measure underlying arterial stiffness, which may have contributed to elevated blood pressure. Finally, studies based on clinical events often capture only relevant and symptomatic disease states, and the observations may not be generalizable to less severe cases of aortic valve disease.

The authors conclude that higher blood pressure had significant associations with increased risk of aortic stenosis and aortic regurgitation. However, the causal nature of the observed associations creates a need for further investigation.

Reference

Rahimi K, Mohseni H, Kiran A, et al. Elevated blood pressure and risk of aortic valve disease: a cohort analysis of 5.4 million UK adults [published online September 12, 2018]. Eur Heart J. doi:10.1093/eurheartj/ehy486