Invasive cardiopulmonary exercise testing in the evaluation of unexplained dyspnea: Insights from a multidisciplinary dyspnea center.

Huang W, Resch S, Oliveira RK, Cockrill BA, Systrom DM,
Waxman AB

Eur J Prev Cardiol. 2017 Jul;24(11):1190-1199.

Unexplained dyspnea is a common diagnosis that often results in
repeated diagnostic testing and even delayed treatments while a determination of
the cause is being investigated. Through a retrospective study, we evaluated the
diagnostic efficacy of a multidisciplinary dyspnea evaluation center (MDEC) using
invasive cardiopulmonary exercise test to diagnose potential causes of
unexplained dyspnea.

Methods We reviewed the medical records of all patients
referred with unexplained dyspnea to the MDEC between March 2011 and October
2014. We assessed the diagnostic efficacy before and after presentation to the

Results During the study period a total of 864 patients were referred to
the MDEC and, of those, 530 patients underwent further investigation with
invasive cardiopulmonary exercise test and constituted the study sample. The
median age was 57 (44-68) years, 67.2% were women, and median body mass index was
26.22 (22.78-31.01). A diagnosis was made in 530 patients including: exercise
pulmonary arterial hypertension of 88 (16.6%), heart failure with preserved
ejection fraction of 94 (17.7%), dysautonomia 112 (21.1%), oxidative myopathy of
130 (24.5%), primary hyperventilation of 43 (8.1%), and other 58 (10.9%). The
time from initial presentation to referral was significantly longer than time to
diagnosis after referral for non-standardized conventional methods versus
diagnosis through MDEC using invasive cardiopulmonary exercise test (511 days
(292-1095 days) vs. 27 days (13-53 days), p < 0.0001). In a subgroup analysis, we
reviewed that patients referred from cardiovascular clinics were more likely to
have a greater number of diagnostic tests performed and, conversely, patients
referred from pulmonary clinics were more likely to have a greater number of
treatments prescribed before referral to MDEC.

Conclusions As a result of this
retrospective study, we have evaluated that a multidisciplinary approach that
includes invasive cardiopulmonary exercise test dramatically reduces the time to
diagnosis compared with traditional treatment and testing methods.