Despite advancements in diagnostics and treatments, cardiovascular diseases (CVDs) are still the leading cause of mortality in the world, accounting for more than 17.9 million deaths each year(1). There are also many preventive programmes aimed at educating the general public about the dangers of CVDs, but these often concentrate on heart-related diseases, such as Coronary Artery Disease (CAD), and neglect others such as vascular diseases, much to the detriment of those affected.
There are several diagnostic methods and tools for checking the health or arteries and other blood vessels in the human body and many of them are not exclusively limited to vascular diseases but are used to diagnose cardiovascular issues in general. We will limit ourselves to those that are more vascular disease-oriented. It should be noted that, aside from how they work, there are significant differences between them, the most pertinent of which, for the patient at least, is their invasive or non-invasive natures. Some require (physical) entry in the human body and can be done only in specialised laboratories, while others, such as the ABI test for PAD, can be conducted in a general healthcare facility.
Diagnostic methods – overview
- Physical exam. Physician can use a stethoscope to check specific arteries for bruit, an abnormal sound generated by the turbulent flow of blood due to an obstruction (plaque in atherosclerosis) in the artery.
- Intravascular Ultrasound (IVUS). This is as similarly invasive as angiography, but it differs in the mechanism by which it detects plaque and obstructions. Instead of a contrast medium, a miniature ultrasound probe is introduced in the blood vessel for precise visualisation of plaque. This is a major advantage in comparison with angiography, but wider usage of IVUS method is limited by high equipment costs.
- Angiography (arteriography). An invasive diagnostic procedure that requires the introduction of a special dye (contrast medium) into the bloodstream through a catheter. The selected part of the (cardio)vascular system is then subjected to X-ray imaging, which shows any obstructions and blockages.
- Ankle-brachial Index (ABI) measurement. Measurements of blood pressures in the arms and legs are made and used in the calculation of ABI, with its value indicative of PAD.
Of these diagnostic methods, only ABI measurement is generally used in large-scale preventive screening of individuals at risk of CVDs as it is the quickest method, the most cost-efficient and is more reliable in comparison with physical examination with a stethoscope (due to human error). There are also differences between the methods of measuring ABI.
Methods of measuring ABI
- Doppler method. The patient is placed in a supine position while the examiner measures blood pressure on both arms and legs using a blood pressure meter and a Doppler probe (a device that utilises ultrasound to detect the flow of blood through blood vessels). After all data is gathered, the examiner manually calculates the ABI. An entire examination may take up to 30 min and requires a specially trained examiner (physician or a nurse) and is often conducted in specialised healthcare facilities.
- Oscillometric method (MESI ABPI MD®). The patient is placed in a supine position and the examiner places three inflatable cuffs on both arms and one leg. The MESI ABPI MD® device then automatically takes measurements and calculates the ABI. This entire procedure takes only 1 minute, does not require any special preparation and can be conducted by virtually any healthcare professional (only minimal training required). As such it is increasingly used by primary care physicians for preventive PAD screening of patients in general practice.
The ABI is the best way of detecting PAD and indirectly of CVD risk, and with the proliferation of diagnostic devices, such as MESI ABPI MD®, in healthcare facilities worldwide, more and more people have a chance to check their cardiovascular health. Only proper and timely diagnosis can lead to effective preventive treatment and avert or at least mitigate serious issues.