What is the role of imaging studies in the workup of low HDL cholesterol (hypoalphalipoproteinemia)?

Updated: May 21, 2021
  • Author: Vibhuti N Singh, MD, MPH, FACC, FSCAI; Chief Editor: George T Griffing, MD  more...
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Answer

See the list below:

  • Whether imaging studies are needed depends on the clinical manifestations of hypoalphalipoproteinemia (HA).

  • Patients with corneal opacification may require ophthalmoscopic examination and corneal or intraocular imaging.

  • Patients with premature coronary atherosclerosis may need the following:

    • Chest radiograph - A chest radiograph may show alteration in the size of the cardiac silhouette; calcification or congestion of the lung fields, including interstitial edema; and Kerley B lines, indicating congestive heart failure.

    • Echocardiogram - Two-dimensional, ultrasonographic images of the heart can show chamber-size alterations, regional wall motion abnormalities, and valvular regurgitations consistent with the presence of atherosclerosis.

    • Nuclear (radionuclide) stress test - The quantity of blood that flows to different parts of the myocardium can be evaluated, using a nuclear (gamma single-photon emission computed tomography) camera to reveal the presence of a hot spot (good flow) or a cold spot (diminished flow). A radioactive isotope, such as thallium, sestamibi, or tetrofosmin, is used, and the image is produced once with patient exercise and then in the absence of exercise. If a patient cannot exercise, pharmacologic agents (eg, adenosine [Adenocard], dipyridamole [Persantine], dobutamine [Dobutrex]) can be used to stimulate the heart muscle for the stress test. This test is expensive but noninvasive, and its accuracy is quite high (>93%).

    • Stress echocardiography - Instead of using a radionuclide agent, echocardiographic (ultrasonographic) images can be obtained immediately following incremental exercise on the treadmill or after the administration of intravenous dobutamine. In this test, the ventricular wall motion during stress is compared with that at rest. Wall motion decreases during stress in a coronary artery that has significant obstruction.

    • Electron beam (ultrafast) computed tomography (CT) scan - This test is noninvasive but somewhat controversial. By measuring the amount of calcium deposited in the plaques of coronary arteries, it can detect even 10-20% blockages, which other tests may not reveal. The only recommendations for such insignificant blockages are lifestyle changes and risk-factor modification. Also, because elderly people frequently have calcium in their coronary arteries without significant narrowing, electron beam CT is of limited value for persons in this age group. The advantage of electron beam CT is that it can be used to noninvasively screen young people with 1 or more heart disease risk factors.

    • Coronary angiography by cardiac catheterization - Performed in the hospital, this test involves intravenous placement of long, thin, plastic catheters into the opening of the coronary arteries, starting from either the groin (femoral artery) or the arm (brachial artery). Once the catheter reaches the opening of the coronary artery, a small amount of radiographic iodine dye is injected, which makes the coronary arteries visible on radiographs. Pictures of the coronary arteries are recorded for later review. The images show the diameter of the coronary arteries and reveal any blockages that are narrowing them. Coronary angiography is an invasive test. In experienced hands, the risk of complications from the procedure is less than 1%. It is the only test that helps a cardiologist to determine precisely whether to treat a patient using bypass surgery, through-the-skin intervention (percutaneous coronary interventions) such as angioplasty or stent placement, or medicines alone.

  • Some imaging studies may be included in the workup for exploring secondary causes of HA.


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