17 July 2012
The Vanderbilt Heart and Vascular Institute (VHVI) now offers a minimally invasive, catheter-based approach to dissolving pulmonary embolism, a potentially life-threatening blood clot that form elsewhere in the body and travels into the lungs.
A pulmonary embolism (PE) is one of those sneaky, and dangerous, conditions that can appear in perfectly healthy people, perhaps after a long flight or, as in the case of veteran NBC News reporter David Bloom, after sitting in a cramped military tank for several hours. Bloom died in 2003 after suffering a deep vein thrombosis, a large blood clot that formed in one of his legs and traveled to his lungs to create a PE.
Summer travelers and others who are at increased risk for PE are encouraged to move about the airplane cabin or stop their cars at least once an hour to walk briefly. Also, proper hydration along with exercising leg muscles while seated by flexing calf muscles and ankles can help prevent PE.
Cancer patients, trauma patients and even women on birth control pills who are genetically predisposed to hyper coagulation are all at increased risk for pulmonary emboli. Each year, about 600,000 people develop PE, which can be marked by symptoms such as shortness of breath, chest pain, rapid heart rate and fainting, all of which can mimic a heart attack. Nearly half of those diagnosed with PE die because the blood clot obstructs the major blood vessels leading from the heart to the lungs.
By using the new EKOS catheter, Vanderbilt’s interventional cardiologists are able to infuse a clot-dissolving drug known as tPA directly into the pulmonary embolus. The EKOS catheter uses ultrasound during the drug infusion, which pulls apart the fibrin particles to allow the medicine to get into the center of the clot, accelerating dissolution.
This approach is reserved for patients who are in stable condition but have a dysfunctional and enlarged right heart ventricle. These patients have a higher risk for becoming acutely unstable, developing chronic pulmonary hypertension in the intermediate-to-long term, and mortality, said Pete Fong, M.D., assistant professor of Medicine.
“Typically, cardio-thoracic surgeons will be consulted to evaluate patients with large pulmonary emboli to determine if they are appropriate candidates for surgery,” Fong said. “If they are not, then interventional cardiologists will see if a catheter-based approach should be offered. We are able to care for these patients through a team approach unique to Vanderbilt Heart.”
In the past, patients with sub-massive PE were given heparin and Coumadin, which kept the clot from growing and new clots from forming, but did not remove them.
“The catheter-based approach improves the patient’s condition within minutes to hours of initiation and utilizes one-third of the thrombolytic therapy used in systemic administration, making it less likely to cause major bleeding. It is much less invasive than open heart surgery,” Fong said.
Last year, Vanderbilt implemented a Level 1 Cardiac Emergency System, designed to deliver coordinated, expedited care for heart patients with complex and life-threatening problems, including myocardial infarction, cardiogenic shock, acute pulmonary embolism and aortic dissection. VHVI has now treated three PE patients utilizing this protocol.