Background: Philippine data on outcomes of acute coronary syndrome (ACS) patients post "acute phase" is limited. This study attempted to determine significant association of distance walked by ACS patients in the 6-Minute Walk Test (6-MWT) and incidence of major adverse cardiovascular events (MACE) within 180 days (6 months) post-test.
Methods: This is a prospective cohort study of ACS patients at the Philippine Heart Center (PHC) who underwent 6-MWT during discharge from May 2013 to October 2014 and were followed for 180 days for MACE (i.e. composite of Non-fatal MI, Stroke, and Cardiovascular death) and Secondary Outcomes (i.e. composite of All-Cause Death Non-fatal MI, Stroke and Heart Failure and each component outcome). Cut-off distance predictive of MACE was determined.
Results: Hypertension (p=0.04), lower Troponin I (p=0.03), SBP (p=0.00) and HR (p=0.03) elevation post-6-MWT and elevated baseline oxygen (O2) saturation (p=0.04) were baseline parameters significantly associated with MACE. A cut-off distance of 320 meters was predictive of MACE with 35.44% sensitivity and 35.26% specificity. The 6- Minute Walk Distance (6-MWD) was not associated with MACE but significantly associated with secondary outcomes specifically all-cause death(p=0.001), cardiovascular death(p=0.008), heart failure(p=0.007) and its composite(p=0.001).
Conclusion: 6-MWD was not associated with MACE but significantly associated with the composite outcome of all-cause death, non-fatal MI, stroke and heart failure primarily driven by all cause death at 30, 90, and 180 and heart failure at 90 and 180 days post discharge. The 320m cut-off has low sensitivity and specificity hence, it could not be used solely in predicting MACE among ACS patients 6 months post discharge.