Vascular Testing & the Patient
What is a vascular sonographer?
A vascular sonographer or technologist performs non-invasive diagnostic examinations of the arteries and veins of the body. It is important that your sonographer is credentialed. A sonographer can be credentialed through Cardiovascular Credentialing International or American Registry for Diagnostic Medical Sonography. A credentialed sonographer satisfies certain educational standards within the profession and they have passed exams to test their knowledge and competency.
Facts to know about vascular laboratory diagnostic studies
A vascular laboratory diagnostic study should be:
- Performed in a facility in which the laboratory is accredited in vascular technology. Appropriate vascular laboratory accreditation may be earned through the Intersocietal Accreditation Commission or the American College of Radiology
- Performed by a technologist who is credentialed in vascular technology. Appropriate certification includes the Registered Vascular Technologist (RVT), the Registered Vascular Specialist (RVS) or Registered Phlebology Sonographer (RPhS)
- Interpreted by a physician who is competent in diagnostic vascular studies or under the supervision of physicians who have demonstrated competency by being credentialed in vascular technology. An appropriate credential for a physician is the Registered Physician in Vascular Interpretation (RPVI)
Ultrasound (sonography) is a medical imaging modality that uses high frequency sound waves to create an image. Sound waves are safe and do not contain harmful radiation. Sonography is divided into several specialties including obstetrics, gynecology, abdomen, echocardiography (heart imaging), musculoskeletal and vascular.
Vascular ultrasound is the specialty that interrogates the arteries and veins of the body. Combining ultrasound imaging with Doppler ultrasound technologies allows the vascular technologist to evaluate and record blood flow characteristics dynamically in real time.
- The arteries carry oxygenated blood from the lungs and heart to the organs, extremities (limbs) and brain
- Atherosclerosis is the buildup of plaque in the artery which can eventually narrow the vessel and obstruct blood flow
- Cerebrovascular disease is when the blood flow from the heart to the carotid arteries in the neck and then into the brain is compromised. This may lead to a "mini stroke," also known as a transient ischemic attack (TIA). If symptoms last longer than 24 hours, the event is called a stroke or a cerebrovascular accident (CVA)
- Peripheral arterial disease, (PAD), is a very common condition that affects 1 in 20 people over the age of 50 in the United States. When there is not enough blood flow to the limbs, a person may experience fatigue, heaviness or pain in the muscles of the buttocks, thighs or calves while walking. The pain felt is known as claudication. This discomfort lessens with rest but will return with more exercise. Severe PAD can eventually lead to pain in the legs while resting. Patients with severe PAD may get infections or non-healing sores in the limbs, most specifically in the feet or toes
- An aneurysm occurs when the arterial walls weaken and expand, creating a dilatation in the artery. Your physician may feel a pulsatile mass on a physical exam. These areas are often associated with atherosclerosis and present the risk for rupture
- Renal (kidney) artery disease occurs when the arteries to the kidneys are narrowed, potentially leading to high blood pressure
- Mesenteric artery disease occurs when the arteries that feed the digestive organs are not delivering enough blood to the bowels due to plaque buildup. Primary symptoms include pain in the abdomen after eating that can lead to avoidance of food and weight loss
Risk Factors of Arterial Disease
- High blood pressure
- High cholesterol levels
- Heart disease
- Family history of arterial disease, aneurysm, stroke and/or heart disease
- The veins carry deoxygenated blood from the limbs, organs and brain to the heart.
- Blood clots can form in the veins and obstruct flow back to the heart resulting in swelling and pain in the extremities (limbs). A blood clot can possibly break off and travel to the lungs causing a pulmonary embolism (PE). Symptoms include shortness of breath and pain if this occurs
- Deep vein thrombosis (DVT) is a blood clot in the deep venous system. Patients are more at risk for a PE when diagnosed with DVT
- Superficial vein thrombosis (SVT) is a blood clot in the superficial system or near the surface of the skin. This may cause redness and pain in the limb but is typically not treated as aggressively since the risk of PE is lower than DVT
- Veins have valves that keep blood moving back to the heart by preventing blood from back-flowing into the limbs This is especially important when we are standing or sitting and gravity pulls the blood toward the feet
- Venous insufficiency is when the valves are damaged and blood pools in the legs which can lead to varicose veins, swelling, pain, skin discoloration and venous ulcers
Risk Factors for Venous Disease
- Use of oral contraceptives or hormone replacement therapy
- Recent surgery or trauma
- Prolonged immobilization
- Cancer and cancer treatment
- Past history of venous thrombosis
- Inherited clotting disorder
- Family history of varicose veins
Types of Exams
Extracranial Carotid Ultrasound Examination
When the sonographer examines the arteries going up the neck and into the brain. This includes the innominate or brachiocephalic, subclavian, vertebral, common carotid, internal carotid and external carotid arteries.
Carotid Artery Ultrasound Image
Abdominal Aortic Ultrasound Examination
When the sonographer assesses the large artery in the abdomen that carries blood from the heart through the abdomen and into the legs with diagnostic ultrasound. Diameter measurements are taken to screen for a dilatation in the vessel wall, also known as an aneurysm or for follow up on a patient with a known abdominal aortic aneurysm.
Abdominal Aortic Ultrasound Image
Renal Duplex Examination
When the sonographer assesses the main arteries leading to the kidneys and the kidney tissue, ensuring there is adequate blood flow.
Left Kidney Flow Ultrasound Image
Mesenteric Ultrasound Examination
When the sonographer assesses the patency of the blood flow in the arteries that feed the digestive system.
Upper Arterial Duplex Examination
When the sonographer assesses the arteries in the arms and fingers. Segmental blood pressures can also be taken in the arms and fingers to assess patency.
Lower Arterial Duplex Examination
When the sonographer assesses the arteries in the legs. Segmental pressures and pulse volume recording can also be included. The common iliac, external iliac, common femoral, superficial femoral, profunda, popliteal, anterior tibial, posterior tibial and peroneal arteries are typically assessed.
Lower Extremity Artery Ultrasound Image
Upper Venous Duplex Examination
When the sonographer assesses the veins in the neck and arms including the internal jugular, innominate, subclavian, axillary, brachial, ulnar, radial, cephalic and basilic veins.
Lower Venous Duplex Examination
When the sonographer assesses the veins in the legs including the external iliac, common femoral, femoral, popliteal, gastrocnemius, posterior tibial, peroneal, greater saphenous and small saphenous veins.
Lower Extremity Vein Ultrasound Image
Vascular Access Site Examination
When the sonographer assesses blood flow in the acquired arteriovenous fistula or arteriovenous graft including inflow and outflow access sites.
Screening for Abdominal Aortic Aneurysm
An abdominal aortic aneurysm (AAA) is when the wall of the aorta weakens and bulges out. Treatment of the aneurysm will depend on the size of the aneurysm. Medicare Part B will cover a one-time AAA screening ultrasound examination if you have a family history an AAA. You may also qualify if you are a male ages 65 - 75 years old and have smoked at least 100 cigarettes in your lifetime. An AAA is less common in women who have never smoked. Patients will need a referral from their doctor for this exam.
The vascular laboratory also performs physiological examinations on patients to assess arterial blood flow in the extremities. Physiologic testing includes taking segmental blood pressures and acquiring arterial waveforms at various levels in the extremities and digits. In addition, photoplethysmography can also be performed on the digits using an infrared light to investigate small blood vessels under the skin surface.
A common test performed in the vascular laboratory includes taking blood pressures in the arms and ankles and calculating the ratio between these pressures. This is called the ankle brachial index (ABI). A normal ABI is 0.95 - 1.3. Combined with arterial waveforms, this is a powerful and frequently used test to identify PAD and its severity.
Blood pressure cuffs can also be applied to the thigh, calf, ankle, foot and fingers. Arterial waveform recordings and segmental blood pressures can be performed on the extremities to determine the location of blockages in the arteries.
Physiological Testing Segmental Blood Pressure Cuffs
Physiologic exercise testing may also be performed which includes walking on a treadmill for five minutes or less at a comfortable speed and then taking blood pressures and arterial waveforms after exerting the muscles. This helps to identify whether symptoms are related to PAD.
Physiological Testing Results Report
Before the Exam
For exams of the arteries or veins in the abdomen such as aorta, inferior vena cava, mesenteric vessels, kidneys, liver or spleen, do not eat or drink for six to eight hours before the examination. Drinking water while taking medications is fine, but please don't drink coffee or smoke tobacco products prior to examination. This allows the technologist to best visualize the vessels and organs in the abdomen and provide more accurate results for your doctor.
For peripheral arm or leg arteries and veins being tested, no preparation is needed.
For exams of the arteries or veins in the neck, there is no preparation needed. For your comfort, wear a low collared shirt so the technologist can access your neck.
During the Exam
Depending on the type of examination or test being performed, the sonographer may have you change into a gown and remove your jewelry or watch if necessary. While laying on your back, a trained vascular sonographer or technologist will perform the examination by applying a water-soluble gel to the skin and placing a transducer on your skin. Depending on the exam, the sonographer might ask you to reposition onto your side or stomach, hold your breath or perform a Valsalva maneuver (hold your breath while bearing down on your lower pelvic muscles). If the examination is a venous duplex checking for blood clots, the sonographer will apply pressure to the skin making sure the vein collapses. This may be uncomfortable, but the sonographer is performing the exam so your doctor can decide further action. The diagnostic testing may take 15 to 60 minutes to perform.
After the Exam
Once the examination is complete, the images are sent to the interpreting physician, who will create a final report based on the findings of your exam and send the results to your physician.