Abstract MP44: Assessment and Comparison of Six minute Walk Distance in Patients Undergoing Pharmacological Stress Test
Background: Stress testing is widely used for diagnosis, risk stratification and prognosis of patients (pts). Although a normal stress study identifies pts at low risk, compared to exercise stress (Ex), those undergoing pharmacological stress test (PST) are at a higher risk of mortality. We studied the feasibility of a six minute walk test (SMWT) and compared the six-minute walk distance (SMWD) among Ex and PST.
Methods: 328 consecutive patients [Ex=186 (57%); PST= 142 (43%)] referred for stress testing at our hospital were enrolled. Demographic and clinical information was collected. Each patient underwent a SMWT according to American Thoracic Society guidelines.
Results: Patients in PST were older (62±14 vs. 57±12; p=0.001), had a higher BMI (36±30 vs. 29±6; p0.01), diabetes (46% vs. 25%; p<0.001) and hyperlipidemia (55% vs. 38%; p=0.01). We found a low SMWD achieved in PST (209 m ± 131) vs. Ex (366 m ± 107; p<0.001). When compared to age-gender matched healthy volunteer data, we found a significantly lower predicted SMWD in all patients suspected of CAD, with the lowest predicted SMWD in PST. (Figure) On multivariate analyses, patients undergoing PST had the highest risk (HR=10.1) of achieving lowest tertile of percent predicted SMWD, followed by female gender (HR=2.0), history of CHF, higher BMI. Only patients above 80 yrs of age had significant higher likelihood of undergoing pharmacological stress mode (OR = 7.2; 95CI =1.7 - 30.1; p=0.008). After including the interaction term for age and pharmacological stress mode, low SMWD among PST was seen in both older and young patients (p for interaction=0.46).
Conclusion: SMWT is feasible in patients referred for PST. Patients with known or suspected CAD achieve a low percent predicted SMWD. This is the first study to show objective evidence of deconditioning in PST irrespective of co-morbidities. Future studies are needed to evaluate the prognostic significance of SMWT in patients undergoing pharmacological stress test.
Author Disclosures: A.A. Supariwala: None. S. Uretsky: None. R. Cohen: None. Y. Thammaiah: None. S. Sangli: None. A. Correa: None. M. Duttuluri: None. S. Dukkipati: None. K. Price: None. I. Khan: None. F.A. Chaudhry: None. A. Rozanski: None.
- © 2014 by American Heart Association, Inc.