Undiagnosed chronic respiratory disorders in symptomatic patients with initially suspected and excluded coronary artery disease: insights from a prospective pilot study

Abstract

Background: Chronic respiratory diseases represent the third-leading cause of death on a global scale. Due to mutual symptoms with cardiovascular diseases and potential inappropriate attribution of symptoms, pulmonary diseases often remain undiagnosed. Therefore, we aimed to evaluate the prevalence of chronic respiratory disorders among symptomatic patients in whom suspected coronary artery disease (CAD) was ruled out.

Methods: After CAD was excluded by invasive coronary angiography (ICA), 50 patients with chest pain or dyspnea were prospectively enrolled in this study. All patients underwent lung function testing, including spirometry and diffusion measurements. At baseline and the 3-month follow-up, standardized assessments of symptoms (CCS chest pain, mMRC score, CAT score) were performed.

Results: Chronic respiratory disease was diagnosed in 14% of patients, with a prevalence of 6% for chronic obstructive ventilation disorders. At 3-month follow-up, patients with normal lung function tests revealed a substantial improvement in symptoms (mean mMRC 0.70 to 0.33, p = 0.06; median CAT 8 to 2, p = 0.01), while those with pulmonary findings showed non-significant alterations or unchanged symptoms (mean mMRC 1.14 to 0.71, p = 0.53; median CAT 6 to 6, p = 0.52).

Conclusion: A substantial proportion of patients with an initial suspicion of coronary artery disease was diagnosed with underlying chronic respiratory diseases and exhibited persistent symptoms.

Keywords: chest discomfort; chronic obstructive pulmonary disease; chronic respiratory disorders; coronary artery disease; dyspnea.

Figure 1

Flowchart depicting study protocol. Created with BioRender.com. CAD, coronary artery disease; ICA, invasive coronary angiography.

Figure 2

Frequencies of the various manifestations of chest discomfort in the study cohort, as classified by ESC guidelines (2019) at two timepoints: Baseline. 3-month follow-up. Data are shown as 10 × 10 dot plots and percentages.

Figure 3

Symptom-score changes between baseline and 3-month follow-up in patients with and without abnormal respiratory tests: (A) modified Medical Research Council (mMRC) score (data provided as mean ± standard deviation). (B) COPD assessment test (CAT) score (data provided as scatter dot plot and median). CAT, COPD assessment test; mMRC, modified Medical Research Council; Respiratory+, patients with pathological respiratory tests; Respiratory−, patients with normal respiratory tests.

Figure 4

Symptom-score changes in patients with and without abnormal lung tests between baseline and 3-month follow-up, according to the 8 CAT symptom classes. Data provided as mean ± standard deviation. CAT, COPD assessment test; Respiratory+, Patients with pathological respiratory tests; Respiratory−, Patients with normal respiratory tests.