Pulse Volume Recording (PVR)
What is Pulse Volume Recording, and Why Am I Having It?
A PVR, also called plethysmography is, a noninvasive diagnostic tool that measures blood flow within the arteries, primarily, but not limited to, the legs to diagnose narrowing or obstruction in the vessel. The measurements obtained help locate where the blockage is within the artery, for example, the thigh or lower leg.
You may already have been diagnosed with coronary artery disease and have a cardiac stent so your doctor may wish to rule out any peripheral vascular disease as well. Just as you developed that sticky stuff called plaque in your coronary arteries you may also develop plaques in the arteries t hat feed your leg muscles.
You may have told your doctor that when you walk or go up a long flight of stairs you feel a tightness, heaviness, cramping or weakness in your leg. It goes away when you rest. This is called" claudication" and is most often the first sign of peripheral artery disease or narrowing in one of the major leg arteries. With moderate to advanced leg disease you may have pain in your feet and toes even at rest. In severe leg artery disease you may develop painful sores on your legs and toes and if the circulation is not restored you may develop a condition called gangrene.
Some of the risk factors that increase your risk of developing peripheral vascular disease include:
- Being over 50 years of age
- Smoking
- Diabetes
- High blood pressure
- High cholesterol
- High levels of a certain amino acid called homocysteine
- Obesity
As well as a diagnostic tool, the PVR is also used to assess the effectiveness of a recent peripheral artery stent procedure that you had done on one of your limbs. This will be scheduled at routine time intervals, usually at 4 weeks, 6 months and 12 months post intervention.
What do I do in preparation for a PVR, how long does it take and when can I expect the results?
The only preparation needed for a PVR is that you refrain from smoking for at least 30 minutes before the test. Smoking tends to constrict he blood vessels.
The PVR exam will take approximately 45 minutes to complete. It will be done by a nurse, vascular technologist or trained medical assistant. You will be asked to remove trousers, shoes and socks. A drape will be provided to cover your lower body. You will lie on the exam table in a semi-recumbent position( head of bed up 30-45 degrees) and the technician will place 3 blood pressure cuffs on your legs, 1 on the thigh, 1 on the calf and the other on the ankle. The cuffs are then connected to a machine known as a pulse volume recorder which measures the amount of blood at various points in the legs.
The pulses appear as wave forms on a chart, The amplitude and shapes of these wave forms will help the interpreting cardiologist diagnose possible blockages. In addition blood pressure readings are taken in the arms and ankles and then compared. This is called an ankle-brachial index or ABL. And finally, a doppler is used to measure blood flow velocities in the major leg arteries and can be heard as a "whooshing" sound. In general, the higher the velocities over and above a norm, the narrower the vessel. This completes the PVR exam.
The interpreting cardiologist will prepare a report within 48 hours. The report will be sent to the requesting physician who will discuss the results with you.
