Penumbra, Inc
Innovation In Pulmonary Embolism Treatment
James F. Benenati
Acute pulmonary embolism (PE) is common, affecting more than 300,000 people in the U.S. each year. The severity of these blood clots in the lungs cannot be understated. They are complicated to diagnose – there are many variable clinical presentations— and, if not treated quickly, can at times be lifethreatening.
When I first became a practicing interventional radiologist 30+ years ago, treatment for PE was limited to anticoagulation therapy. This is still considered standard-of-care today. More recently, thrombolytic therapy has become common place for life threatening pulmonary emboli but this therapy comes with a host of potential complications. Patients may experience excessive bleeding and use of these thrombolytic agents also require stays in monitored care units or the intensive care unit (ICU).
Over the past decade, advancements in technologies have allowed for the development of potentially more efficient clot removal methods for patients with pulmonary emboli that are causing severe symptoms such as shortness of breath, tachycardia (fast heart rate), low blood pressure and other life-threatening symptoms.
The following is a brief overview of how the treatment of PE has evolved beyond drug treatment to include advanced technology.
Mainstay PE Treatment: Anticoagulation and Thrombolysis
Anticoagulation has been the mainstay of PE treatment. These medications decrease the blood's ability to clot, and patients with PE typically take them for 3 to 6 months and sometimes for life. While anticoagulants can be lifesaving because it helps stabilize the patients’ symptoms, these agents do not remove or dissolve the clot. Anticoagulants work by preventing clot from continuing to form and then it is up the body’s own inherent thrombolytic system to try to dissolve the clot. While this works well with less symptomatic clot, patients with larger clots can experience lasting debilitating symptoms and these symptoms can affect the patient’s well-being for the remainder of their life.
Another treatment option for PE has been thrombolytic therapy, or thrombolysis, which uses medications to dissolve the blood clots and prevent new clots from forming. The most commonly used drug for thrombolytic therapy is tissue plasminogen activator (tPA). Thrombolysis is performed in the hospital setting to dissolve the clots and improve cardiorespiratory hemodynamics. However, careful patient selection for this therapy is critical as it is associated with several potential complications, including bleeding that can be catastrophic. As a result, not everyone can be treated with thrombolytics and patients need to be closely monitored in either a monitored bed or an ICU post-procedure.
New Approach— Removing Clots with Mechanical Thrombectomy
Given the limitations of anticoagulation and thrombolytic therapy, physicians have been searching for years for a safer and more efficient way to manage pulmonary emboli as well as blood clots in arteries and veins. Penumbra Inc. was instrumental in pioneering the mechanical thrombectomy to remove blood clots in the brain for stroke using a continuous aspiration pump and specially designed atraumatic catheters. This technique of removing clot in the brain worked well and revolutionized the way clot was managed in strokes.
With this as a background, a number of physicians began to adapt similar techniques to clear blood clots from arteries in the legs. As one of the early pioneers to look at this new form of therapy, I helped the Penumbra team develop catheters for use outside the brain. In a short period of time, it became obvious to many that this thera py would work in di ffe rent p arts o f the b ody. Soon after t his we beg an to develo p cathe ter s and aspira ion sy stems f or lar ger vessel s su ch as vein s and pulmon ary a rteries.
Thi s early wo rk le d to what would bec ome Pe num bra’s I ndig o Aspiratio n System, wh ich use s conti nuous aspi rat ion th rombec tomy to r emove blood c lots thr oughout the b ody. The I ndigo S ystem has continue d to evolve si nce it was first int roduced and now uses a u nique comput er-a ided cl o tde tection technol ogy t hat can diff ere ntiate f or the u ser betw een clo and flowing bloo d by i ndica i ng to the physician whethe r the c atheter is e ngaged in thr ombus with audiovisual cue s. Th is ad ance d technol ogy is call ed Lightn ing Asp ira ion. It is de sig ned t o reduce blood loss an d the need for cl ot- dissolvi ng d rugs, whic h may l ower the risk o f bleed ing complications.
When I first became a practicing interventional radiologist 30+ years ago, treatment for PE was limited to anticoagulation therapy
During a c ont inuous a spiration t hrombectomy p oc edu re, we guid e a c atheter throug h the p atie nt’s arter ies o r veins using X-ray guidanc e to the vess el wher e the clot i s lo cated. The catheter is place d in the c lo and the pump is then turne d on to begin the process of cl o te xtract io n. Advance s in desig n pro vide cathet ers that ar e mo re torq ueable and tra ckable, en bl ing u s to reac h targe t ves sels e ffi ciently. T hese a vancemen ts hveshor ten ed th e time to tr eat p atien ts w ith co ndition s li ke P , as we ll as venous th rom bosis and acute limb ischemia i n th e arteri es. These procedures which are d one wi thout surger y can potentially allow pati ent s to leave t he hospi tal more q uickly vs. trad itiona l treatments.
R cent D ataDemons rat sSaf ty A ndPer ormanceo Mech nicalThrom ecto yin T he B ody
Init ial data of the STRIKE PE s tudy su ggest that Penum bra ’s In digo Aspira ion Sys tem with Ligh tning i s saf e and e ffective for treat ing s ub-massive an d massi ve pulmona ry e mboli i n a re al-world p opula ion.
The pros pective, mult i-center stud y showed that b oth right ventr icle/le ft ve ntricle ratio and pulmonary ar tery pressure s gn ific antly decreas ed by 2 4 pe rcen t and nearly 20 perc ent, resp ectiv ely. The inte rim data also showed i mproved patie nt reported qua lity- of-l ife outcome s, in luding im proved mobili ty an d ability to provide s elf-car e an d a decrease in p ain/ discomfo rt f rom discharge t o 90-day follow -up.
Th e data is encou ragin g as it h ighlights the pos itive impac t these adva cements ca have on patients. To obtain additi onal data, w e al so p l anon lau nchi g a rand omi zed contro lled trial for PE to as sess how m echan ical t hrombec tomy compa res to ant icoagulat ion, the standard o f care. With the growing body of evi dence that supp orts the e ffe ctivenes s of mechani cal t hr mbectomy in t he mana gement of PE , we ma y potential ly s ee a shif t in PE care to inc lude m ech anical thromb ct omy as a frontlin e tre atment opt ion in th e future.
