Patients with ST-elevation acute coronary syndrome (STE-ACS) without obstructive coronary artery disease (CAD) have a lower short-term risk of death. But, their long-term risk of death is similar to or higher than patients with obstructive CAD, according to a study recently published in the European Heart Journal.

Hedvig Bille Andersson, MD, et al., examined short- and long-term survival and causes of death in patients with STE-ACS without obstructive CAD compared with patients with STE-ACS with obstructive CAD and with the general population. All patients with STE-ACS scheduled for acute coronary angiography between November 2009 and December 2014 at Copenhagen University Hospital were identified from the Eastern Danish Heart Registry.

A total of 4,793 patients were included, 6 percent with non-obstructive CAD, 88 percent with obstructive CAD and 5 percent with normal coronary arteries. The median follow-up was 2.6 years. The estimated risk of death within 30 days was 7 percent for patients with obstructive CAD, 4 percent for patients with non-obstructive CAD (hazard ratio [HR], 0.49; p = 0.018 vs. obstructive CAD) and 2 percent for those with normal coronary arteries (HR, 0.31; p = 0.021 vs. obstructive CAD).

According to a 30-day landmark analysis, the long-term risk of death was similar in patients with non-obstructive and obstructive CAD. Patients with normal arteries had an increased long-term risk of death compared with patients with obstructive CAD (HR, 2.44; p < 0.001).

Compared with the general population, the 30-day risk of death was higher for all three groups (p < 0.001), while the long-term risk of death was similar for obstructive CAD (HR, 1.1; p = 0.076) but higher for non-obstructive CAD (HR, 1.55; p = 0.024) and normal arteries (HR, 2.6; p <= 0.001).

The cause of death within 30 days was cardiovascular in 92 percent of patients with obstructive CAD, 75 percent with non-obstructive CAD and 50 percent with normal arteries. The long-term cause of death was cardiovascular in 50 percent with obstructive CAD, 21 percent with non-obstructive CAD and 29 percent with normal arteries.

The authors note that approximately one in nine patients triaged for coronary angiography for STE-ACS did not have obstructive disease in what they believe is the largest study assessing long-term survival and causes of death in STE-ACS patients with and without obstructive disease. These results “suggest that STE-ACS patients without obstructive CAD might benefit from increased medical attention, secondary prevention interventions, and close follow-up,” concluded the authors.