Cardiopulmonary exercise test in patients with subacute pulmonary emboli Yan Topilsky, MD, Courtney L. Hayes, MS, Amber D. Khanna, MD, Thomas G. Allison, PhD* Division of Cardiovascular Diseases and Internal Medicine, Mayo Clinic, Rochester, Minnesota article info Article history: Received 27 February 2011 Revised 26 June 2011 Accepted 30 June 2011 Online 3 September 2011 Keywords: Exercise test Pulmonary embolism abstract Objective: Patients presenting with suspected pulmonary embolism (PE) may present a challenge, particularly if diagnostic testing is not immediately available or clinically not indicated (iodine allergy, pregnancy, renal dysfunction). These patients have abnormal regional gas exchange that can be recognized by a cardio- pulmonary exercise test (CPET), which may become helpful in their evaluation. Methods: A retrospective analysis was performed of outpatients evaluated for subacute exertional dyspnea of 2 to 12 weeks duration with a test for PE and CPET. A total of 108 patients met inclusion criteria. Thirty patients (27.8%) had confirmed PE. Results: The patients with PE had increased nadir ventilatory equivalent ratio for carbon dioxide (VE/VCO 2 ), decreased peak oxygen uptake/predicted, and decreased end exercise saturation (P < .005 for all). All patients but 1 had normal breathing reserve (>15%). A normal nadir VE/VCO 2 excluded PE with 100% sensitivity. By using a “flow chart strategy,” the exercise test had 92.8% sensi- tivity and 92.1% specificity for PE. Eight patients with PE died during follow-up (3.8  4.6 years), 6 of PE-related causes. Peak VO 2 /kg was the best predictor of all-cause mortality and nadir VE/VCO 2 for PE-related mortality. There were no serious complications from any of the exercise tests. Conclusion: PE may be excluded by a normal nadir VE/VCO 2 in patients pre- senting with subacute dyspnea. A combination of decreased peak VO 2 /kg, increased nadir VE/VCO 2 , normal breathing reserve, and exercise-induced desaturation may be sensitive and specific for PE. CPET may assist in identi- fying subacute PE in patients with contraindications to use of computed tomography angiography or ventilation perfusion scans. Cite this article: Topilsky, Y., Hayes, C. L., Khanna, A. D., & Allison, T. G. (2012, MARCH/APRIL). Cardiopul- monary exercise test in patients with subacute pulmonary emboli. Heart & Lung, 41(2), 125-136. doi:10.1016/j.hrtlng.2011.06.009. Conflict of Interest: none Author contributions: All authors made substantial contributions to conception and design or acquisition of data, or analysis and interpretation of data; reviewed and approved the final manuscript; and contributed significantly to this study. * Corresponding author: Thomas G. Allison, PhD, Division of Cardiovascular Diseases and Internal Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN 55905. E-mail address: Allison.thomas@mayo.edu (T. G. Allison). 0147-9563/$ - see front matter Ó 2012 Elsevier Inc. All rights reserved. doi:10.1016/j.hrtlng.2011.06.009