BACKGROUND: Plasma renin activity (PRA) has been related to all-cause mortality and cardiovascular events in patients with cardiovascular disease. However, data from patients with acute coronary syndromes (ACS) are sparse.

METHODS: Determination of PRA was made in 550 patients with ACS, including a subgroup of 287 patients not on treatment with angiotensin converting enzyme inhibitors, angiotensin receptor blockers or diuretics, and without heart failure. We evaluated the relations between PRA and all-cause mortality after three years and long-term, and to cardiovascular events after median 8.7 years. Adjustments were made for variables that influenced the hazard ratio (HR) > 5% for the relation between PRA and outcome.

RESULTS: Baseline PRA was associated with all-cause mortality during three-years (unadjusted HR 1.74 per 1 SD increase in logarithmically transformed PRA; 95% confidence interval (CI) 1.39-2.16, p < 0.0001) and long-term (HR 1.12, CI 1.00-1.25, p = 0.046). After adjustments, only the three-year association remained significant. In unadjusted analyses, PRA was associated with cardiovascular death, but not with nonfatal cardiovascular events. In the subgroup there was an inverse relation between PRA and long-term all-cause mortality.

CONCLUSION: Higher PRA was a significant independent predictor of all-cause mortality after three years, but not at long-term follow-up and not significantly associated with cardiovascular incidence. The renin-angiotensin-system pathophysiology is of great interest, not least due to its association with the COVID-19 pandemic. Our findings indicate a need for further research on the prognostic/predictive aspects of the renin-angiotensin-system in ACS.