IMR Press / RCM / Volume 24 / Issue 4 / DOI: 10.31083/j.rcm2404108
Open Access Original Research
Age, Hypertension, and Exercise Capacity are Independently Associated with Likelihood of Multi-Vessel Disease in Patients Referred for Treadmill Exercise Testing: The Intermediate-High-Workload Treadmill Score (IHWTS)
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1 Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN 55905, USA
2 Division of Biomedical Statistics and Informatics, Mayo Clinic, Rochester, MN 55905, USA
*Correspondence: villarraga.hector@mayo.edu (Hector R. Villarraga)
These authors contributed equally.
Rev. Cardiovasc. Med. 2023, 24(4), 108; https://doi.org/10.31083/j.rcm2404108
Submitted: 27 October 2022 | Revised: 20 January 2023 | Accepted: 2 February 2023 | Published: 17 April 2023
(This article belongs to the Special Issue Cardiac Stress Testing)
Copyright: © 2023 The Author(s). Published by IMR Press.
This is an open access article under the CC BY 4.0 license.
Abstract

Background: To identify factors that increase the specificity of the treadmill exercise test (TMET), and develop a novel scoring system which accounts for functional capacity to aid in determining the need for further testing. Methods: We retrospectively evaluated the electronic health records of 600 patients who had positive TMET results and follow-up stress echocardiography from 1-January-2004, through 31-December-2016. Correlations between clinical and aerobic variables and multivessel disease (MVD) were determined. Duke Treadmill Score (DTS) was calculated and compared with a novel scoring system titled the Intermediate-High-Workload Treadmill Score (IHWTS) that used variables associated with MVD. Results: In total, 124 of 600 patients (21%) had coronary catheterization, and 51 of these patients (41%) had MVD. Mean (SD) DTS was –2.10 (6.3) among patients with MVD vs –0.16 (5) among patients without MVD (p = 0.06). Mean (SD) functional aerobic capacity (FAC) was 76% (20%) among patients with MVD vs 90% (21%) among patients without MVD (p < 0.001). Mean (SD) metabolic equivalent (MET) was 7 (2) among patients with MVD vs 8 (2) among patients without MVD (p = 0.002). Only 6 (12%) of patients with MVD achieved 9 MET or greater on TMET. DTS less than 4 did not distinguish between patients with and without MVD (p = 0.67). Age, hypertension and FAC were independently associated with MVD (all p < 0.05). Conclusions: Our novel scoring system IHWTS utilized age, hypertension, and FAC appeared comparable to DTS to risk-stratify patients regardless of baseline symptoms. Clinical parameters such as hypertension along with exercise functional capacity should be considered when evaluating a positive TMET result in patients that achieve an intermediate-high workload >5 Metabolic Equivalents (METs).

Keywords
coronary artery disease
exercise testing
Intermediate-High-Workload Treadmill Score
preventive medicine
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