Diagnostic value




The common approach for stress testing by American College of Cardiology and American Heart Association indicates the following:

  • Treadmill test: sensitivity 73-90%, specificity 50-74% (Modified Bruce protocol)
  • Nuclear test: sensitivity 81%, specificity 85-95%

(Sensitivity is the percentage of people with the condition who are correctly identified by the test as having the condition. Specificity is the percentage of people without the condition are correctly identified by the test as not having the condition).

To arrive at the patient's post-test likelihood of disease, interpretation of the stress test result requires integration of the patient's pre-test likelihood with the test's sensitivity and specificity. This approach, first described by Diamond and Forrester in the 1970s, results in an estimate of the patient's post-test likelihood of disease.

The value of stress tests has always been recognized as limited in assessing heart disease such as atherosclerosis, a condition which mainly produces wall thickening and enlargement of the arteries. This is because the stress test compares the patient's coronary flow status before and after exercise and is suitable to detecting specific areas of ischemia and lumen narrowing, not a generalized arterial thickening.citation needed

According to American Heart Association data,citation needed about 65% of men and 47% of women present with a heart attack or sudden cardiac arrest as their first symptom of cardiovascular disease. Stress tests, carried out shortly before these events, are not relevant to the prediction of infarction in the majority of individuals tested.dubious – discuss Over the past two decades, better methodscitation needed have been developed to identify atherosclerotic disease before it becomes symptomatic. These detection methods include anatomical and physiological methods.

Examples of anatomical methods
  • CT coronary calcium score
  • Coronary CT angiography
  • Intima-media thickness (IMT)
  • Intravascular ultrasound (IVUS)
Examples of physiological methods
  • Lipoprotein analysis
  • HbA1c
  • Hs-CRP
  • Homocysteine

The anatomic methods directly measure some aspects of the actual process of atherosclerosis itself and therefore offer the possibility of early diagnosis but are often more expensive and may be invasive (in the case of IVUS, for example). The physiological methods are often less expensive and safer but are not able to quantify the current status of the disease or directly track progression.citation needed

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