Small artery structure during antihypertensive therapy is an independent predictor of cardiovascular events in essential hypertension.

OBJECTIVE

Structural changes of small resistance arteries occur early in the disease process of essential hypertension and predict cardiovascular events in previously untreated patients. We investigated whether on-treatment small artery structure also identifies patients at elevated risk despite normalization of blood pressure (BP).

METHODS

We conducted a long-term follow-up survey of cardiovascular events in 134 moderate-risk patients with 9-12 months of well treated essential hypertension. All participants underwent subcutaneous biopsies with determination of small artery structure in terms of media to lumen ratio (M : L) before and during treatment.

RESULTS

After 9-12 months of treatment SBP was lowered from 164 ± 15 to 134 ± 14 mmHg (P < 0.01) and M : L reduced from 0.084 ± 0.028 to 0.075 ± 0.024 (P < 0.01). Mean follow-up hereafter was 15 years representing a total of 2035 years for the entire cohort. During this period 47 patients suffered a predefined cardiovascular event. For patients with on-treatment M : L above the mean value of the cohort (≥0.075), the hazard ratio was 2.14 [95% confidence interval (CI) 1.19-3.84, P = 0.01] and also those with M : L above mean +2SD of a normotensive population (≥0.098) had an elevated risk (hazard ratio 2.99, 95% CI 1.60-5.58, P < 0.01). Both results were adjusted for heart score (a 10-year mortality risk estimate integrating age, sex, smoking status, cholesterol level and SBP). Analysis of changes in M : L during treatment showed significantly higher event rates among patients with increased M : L and vice versa (hazard ratio 1.36 per 25% change, 95% CI 1.07-1.73, P = 0.013).

CONCLUSION

On-treatment small artery structure identifies individuals still at increased cardiovascular risk despite long-term BP normalization and may be an additional target for therapy to prevent cardiovascular events.