Ultrasound Facilitated Pulmonary Embolism Treatment
When a person develops a Deep Vein Thrombosis (DVT) it can travel and block a pulmonary artery to the lungs – a condition referred to as Pulmonary Embolism (PE), there is a window of opportunity in which the clot can be dissolved and normal blood flow resolved.
Until recently, the routine treatment for PE was simply anticoagulation therapy (blood thinning drugs). Anticoagulants alone do not actually dissolve a clot, nor can they restore blood flow to the vessel. So while they reduce the risk of blood clots moving from deep veins typically in the legs and blocking a pulmonary artery to the lung (PE) – they cannot eliminate it.
(DVT can develop if individuals have certain medical conditions that affect how blood clots. It also can happen if you don’t move for extended periods of time, such as following an accident or surgery or being confined to bed.)
A clot can harden and potentially damage both the vein and the valves that regulate blood flow. When this happens, the patient may develop the chronic complications associated with Post-Thrombotic Syndrome.
However, interventional radiologists at St. Bernards now have a tool in their arsenal that improves treatment for patients with DVT.
It uses ultrasonic waves in combination with clot-dissolving drugs to dissolve a clot, reducing the risk of pulmonary embolism. It does not require general anesthesia. The physician inserts a special catheter (long, flexible tube) into a vein and uses image-guided technology to thread the catheter to the clot. There is no sensation of the catheter moving because there are no nerve cells in blood vessels.
Inside the specialized catheter are low-power micro transducers. Once the catheter is in place, the system, manufactured by EKOS Corp, transmits low-power, high-frequency sound waves into the clot. The ultrasonic energy loosens the tightly bound clot and, at the same time, the system forces clot-dissolving drugs deep inside the clot. The combination of the sound waves and drugs gently dissolves the clot without breaking it apart.
This treatment for DVT is most effective when the clot is relatively new, with a patient usually experiencing symptoms for less than 30 days.
The treatment uses clot-dissolving drugs – but at lower dosages than older techniques required – so while there is a risk of bleeding, it is not as great as with older treatments.
The procedure may not be appropriate for people who already have a risk of bleeding or who have blood disorders. After treatment, patients still may need to be on blood thinners to assure another clot does not form.
Your doctor will talk with you about other risks associated with this procedure.
This article was written by Dr. Larry “Jack” Johnson, interventional radiologist. Dr. Johnson completed a Vascular/Interventional Radiology Fellowship in 2004, and has been instrumental in bringing new and cutting-edge interventional procedures to St Bernards Medical Center to provide advanced patient care, including renal cryoablation, uterine artery embolization and hepatic chemoembolization.
Dr. Johnson is the past president of Mid-America Interventional Radiology Society and currently serves on the Board Trustees for the Arkansas Medical Society. He is a member of the Society of Interventional Radiology, along with other numerous committees, and actively participates in the AHEC Residency Training program at St. Bernards.