Table 1.
Screening methods for detecting asymptomatic coronary artery ischaemia in patients with diabetes.
| Screening methods | Detection of prevalent CHD | Comments |
|---|---|---|
| Functional tests | ||
| Resting electrocardiogram (ECG) | Low sensitivity and specificity | Widely available, very low cost |
| Exercise ECG | Moderate sensitivity (45–61%) and specificity (70–90%) | Relatively low cost, widely available Many patients unable to exercise Some have uninterpretable baseline ECGs |
| Radionuclide single proton emission computed tomography (SPECT) myocardial perfusion imaging (MPI) | Good sensitivity (80–90%) and specificity (75–90%) The most widely used test to assess silent myocardial ischaemia |
Moderate to high cost Widely available High negative predictive value (95%) Image quality affected by body habitus and large breasts Screening of asymptomatic patients not prognostically useful unless high-risk patients are selected |
| Myocardial perfusion imaging (MPI) with positron emission tomography (PET) | High sensitivity for myocardial viability studies Accurate global and regional measurements of myocardial perfusion, blood flow, and function at stress and rest in a single study |
Better image quality because of higher spatial resolution, less scattered, and fewer attenuation artifacts Lower radiation exposure than SPECT Costly, not universally available |
| Stress echocardiography (i) Exercise stress echo (ii) Pharmacologic stress echo (dobutamine, adenosine, and dipyridamole) |
The sensitivity and specificity are satisfactory (80–85%) Able to assess LV function and valvular abnormalities |
Low cost, widely available Operator dependent Difficulty in interpreting the images in obese persons |
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| Anatomic (imaging) techniques | ||
| Coronary artery calcium score (CAC) | CAC more prevalent in people with diabetes than nondiabetes Closely associated with total coronary artery atherosclerotic plaque burden Predicts incident ischaemia, CHD morbidity and mortality |
Moderate to high cost No differentiation between obstructive and nonobstructive CHD Up to 25% of patients have minimal or no CAC at the time of screening |
| Multidetector-row computed tomography (MRCT) angiography | High sensitivity (83–99%) and specificity (93–98%) | Good sensitivity, specificity, and negative predictive value. High radiation doses High cost |
| Magnetic resonance imaging (MRI) | Good sensitivity (83–90%) and specificity (72–84%) Delayed gadolinium hyperenhancement linked to increased risk of major cardiovascular events Not adequately investigated |
Able to assess myocardial structure and function and characterize ischemic, inflammatory and various types of cardiomyopathies High cost |