Prognostic Value of 6-Minute Walk Distance in Patients Undergoing Percutaneous Coronary Intervention: a Veterans Affairs Prospective Study.

The 6-minute walk distance (6MWD) test is a useful prognostic tool in chronic heart failure. Its usefulness after percutaneous coronary intervention is unknown. In a prospective observational study, patients underwent a 6MWD test within 2 weeks after percutaneous coronary intervention. The primary endpoint was major adverse cardiovascular events (MACE) (death, acute coronary syndrome, and heart failure admission) at one year. Receiver operating characteristic curves and area under the curve were used to determine the 6MWD test's predictive power, and the Youden index was used to measure its effectiveness. A total of 212 patients were enrolled (98% men; mean age, 65 ± 9 yr). Major comorbidities were hypertension in 187 patients (88%), dyslipidemia in 186 (88%), and diabetes mellitus in 95 (45%). Among the 176 patients (83%) who completed the 6MWD test, the incidence of MACE at one year was 22% (acute coronary syndrome in 17%; heart failure admission in 4%; and death in 3%). The area under the curve for MACE was 0.59, and 6MWD was shorter for patients with MACE than for those without (290 vs 326 m; P=0.03). For 39 patients with previous heart failure who completed the 6MWD test, the area under the curve was 0.64 for MACE and 0.78 for heart failure admission. The 6MWD test predicted reasonably well the incidence of MACE one year after percutaneous coronary intervention. In a subgroup of patients with previous heart failure, it fared even better in predicting heart failure admission. Larger studies are needed to confirm these findings.