Clinical cardiopulmonary exercise testing: patient and referral characteristics

Cardiopulmonary exercise testing (CPET) is a well-established procedure for which applications have evolved in several different medical specialties. There are limited data describing how CPET is actually used in clinical practice. Such information would be useful for understanding the clinical conditions and questions likely to be encountered by a referral laboratory, and for informing future research related to the use of CPET.

We retrospectively reviewed 677 consecutive tests performed in a single exercise laboratory to identify characteristics of patients, and the sources and purposes of referral for testing.

Patients ranged in age from 21 to 90 years and averaged more than 2 preexisting medical diagnoses that could affect exercise function. Most patients were referred by subspecialists, with 33% coming from cardiologists, 32% from pulmonologists, 10% from generalists, and 23% from a variety of other medical and nonmedical professionals. Sixty-one percent of tests were requested for diagnostic purposes. Most of these were for evaluating unexplained symptoms, most commonly dyspnea. The other 39% of tests were requested to quantify exercise function in individuals whose medical condition was known. These had diverse indications including preoperative risk assessment, tracking responses to medical treatments, and characterizing abnormal metabolic responses to exercise.

The experience of this laboratory mirrored the range of indications for CPET found in published literature. The spectrum of indications and referral sources underscore both the many causes and implications of exercise intolerance relevant to clinical practice, and the challenges to laboratory personnel for appropriate testing and reporting of data.