OSA in Patients With Acute Coronary Syndrome Correlates With Adverse CV Events

Increasing modifiable risk factors in those with acute coronary syndrome correlated with incident obstructive sleep apnea (OSA) and adverse cardiovascular outcomes, according to a post hoc analysis published in Journal of Thrombosis and Thrombolysis.

Standard modifiable risk factors for cardiovascular disease (termed SMuRFs) are targeted modalities for the prevention and treatment of cardiovascular events in those with acute coronary syndrome. Examples include diabetes, hypertension, hyperlipidemia, and smoking. OSA presents as a potential SMuRF, as 40-60% of those with cardiovascular disease present with OSA, as well as a growing body of evidence suggesting OSA as an independent risk factor for the long-term prognosis of cardiovascular disease.

For the study, researchers sought to interpret the prognostic strength of OSA as a potential risk factor in patients with acute coronary syndrome, stratified by the number of existing SMuRFs.

The researchers conducted a post hoc analysis on the OSA-ACS Project (ClinicalTrials.gov Identifier: NCT03362385), which is a single-center, prospective cohort study that investigated the association of OSA and cardio-cerebrovascular events in patients with acute coronary syndrome. The project consisted of patients aged 18 to 85 years who were hospitalized with acute coronary syndrome in Beijing Anzhen Hospital, Capital Medical University from January 2015 and December 2019. Patient specific SMuRFs were self-reported prior to admission. Those with incomplete sleep studies, diagnosed with central sleep apnea, or managed with regular continuous positive airway pressure were excluded from the study.

Patients were stratified according to the apnea-hypopnea index (AHI), which measures total number of apnea/hypopnea episodes occurring each hour during total time of polygraph recording. The OSA group consisted of an AHIA >15 events per hour, whereas the non-OSA group had <15 OSA events per hour. Primary outcomes were any major adverse cardiovascular and cerebrovascular events (MACCE) that occurred during follow-up at 1-month, 3 months, 6 months, 1-year, and every 6 months thereafter.

A total of 1,927 patients were included in the final analysis, that of which:

• 130 patients (6.7%) had no SMuRF,
• 1264 (65.6%) patients had 1–2 SMuRFs, and
• 533 (27.7%) patients had 3–4 SMuRFs.

A higher number of SMuRFs was associated with an increased AHI.

• Patients with no SMuRF: 14.5 (6.6–23.1)
• Patients with 1-2 SMuRFs: 15.6 (7.0- 28.8)
• Patients with 3-4 SMuRFs: 18.0 (8.5–36.2)

Kaplan-Meier analysis found no difference in the cumulative incidence of MACCE for patients with any different numbers of SMuRFs. Notably, however, a growing trend of cumulative incidence of MACCE was associated with increasing number of SMuRFs during the late follow-up period.

Cox regression analysis, stratified by number of SMuRFs, found OSA in individuals with 3-4 SMuRFs had a significant impact on the incidence of MACCE (adjusted HR, 1.65; 95% CI, 1.06–2.57; P =.026) and ischemia-driven revascularization (adjusted HR, 2.18; 95% CI, 1.03–4.65; P =.042).

Limitations of the study include the overestimation of the disease severity of OSA, as all patients enrolled had acute coronary syndrome. Additionally, as it was a single-center study recruiting patients from China, there is lack of generalizability; further cohort studies are needed to conclude its findings.

The researchers noted, “OSA is associated with an increased risk of MACCE and ischemia-driven revascularization among patients with 3–4 SMuRFs.” “Therefore, screening for OSA should be emphasized in ACS [acute coronary syndrome] patients with 3–4 SMuRFs, and intervention trials should be prioritized in these high-risk patients,” they concluded.