Abstract
One hundred and twenty three patients who were awaiting angiography for the
investigation of chest pain were contacted by post and invited to participate in the
study. Subjects were required to keep a chest pain diary for 14 days, and complete 5
self-report questionnaires examining physical and psychological aspects of their pain.
Ofthe total sample of 123 patients who proceeded to angiogram, 72 (58.5%) were
subsequently found to have Coronary Artery Disease (CAD) and 51 (41.5%) were
found to have Normal Coronary Arteries (NCA). Seventy-two patients agreed to take
part, 48 with CAD and 24 with NCA. This represents a return rate of 66.7% for CAD
patients and 47% for NCA patients.
Comparison ofthe NCA and CAD cohorts using chi-squared and t-tests for
independent samples revealed the main factors found to be significantly associated
with a finding ofNCA were : age (young), sex (female), non-elevated cholesterol,
pain at rest, pain provoked by stress, wakening pain, relief by GTN after more than 5
minutes, and high levels of bodily awareness. Using these factors, a logistic regression
was run. From this, factors which were found to be useful in discriminating between
CAD and NCA patients were age, sex, somatic awareness and wakening pain. There
was also found to be a lesser but consistent association with rest pain, anxiety and
depression. These variables were found to correctly classify 85 % of cases. The
classification of cases differed between groups with 64% ofNCA cases correctly
classified, and 91.5% of CAD cases correctly classified.
When the discriminatory power of this predictive equation was tested prospectively on
a new sample of 74 patients (phase two) it was found to correctly predict 97.8% ofthe
CAD cases and 58.3% of the NCA cases for an overall success rate of 89.5%. The
implications of the results for the management of patients with chest pain and Normal
Coronary Arteries are discussed. By inquiring routinely about psychological factors
when taking a history, cardiologists would stand a better chance of anticipating which
patients have an increased likelihood of having NCA. In addition to minimising
unnecessary investigations, this could better prepare the patient psychologically for
this finding from an early stage and allow more appropriate interventions to be more
readily integrated.
