Pulmonary embolism (PE) has been called a 'silent killer' because it is so difficult to diagnose and treat.[1] While PE can strike at any age, the burden is particularly high among older adults whose PE hospitalization rates have risen and for whom PE causes frequent hospital readmissions and high mortality.[2] Prompt diagnosis and treatment are critical to improving PE survival rates, but can be difficult. Luca Paoletti, M.D., associate professor of medicine and medical director of the Adult Extra-Corporeal Membrane Oxygenation (ECMO) program at MUSC explained, "PE can present very suddenly and very differently. Some patients have shortness of breath, while others have chest pain or syncope. If there's nothing to make you suspect that a patient might have a PE, the diagnosis can get missed."
Although PE is the third leading cardiovascular cause of death in the U.S. (after heart attack and stroke), treatment guidelines and clinical research are limited.[3] "PE patients with hemodynamic instability or syncope are classified as high risk and should get thrombolytic treatment right away,” said Paoletti. “Low risk patients, who just have shortness of breath without hypotension often respond to oxygen and are usually treated with simple anticoagulation therapy. But what about intermediate risk patients? There's no real agreement on the best way to treat those who are in between."
Another challenge is that many cases require urgent intervention, and PE occurs across the spectrum of medical care. Anything from orthopedic surgery to delivering a baby can result in a PE, so treatment decisions must be made in a variety of medical situations. Brian Houston, M.D., assistant professor in MUSC's Department of Medicine and Director of the Mechanical Circulatory Support Program said, "PE is a constantly humbling diagnosis. While traditional risk factors include immobility, prolonged illness or genetic predisposition to blood clots, there's no classic type. PE can strike anyone–young or old, healthy or ill. Even pediatric patients can have one. We've seen patients as young as 19 who had a serious PE after knee surgery."
The desire to improve patient outcomes in the face of these challenges prompted MUSC to join over 40 other medical institutions in 2015, as a founding member of the Pulmonary Embolism Response Team (PERT) Consortium. The PERT concept, pioneered in 2012 by Massachusetts General Hospital, aims to coordinate and expedite PE treatment by establishing a rapid response team of physicians from various specialties. This multidisciplinary approach allows for faster risk evaluation, treatment planning and resource mobilization to ensure patients receive the highest level of care as quickly as possible. Currently, MUSC is the only PERT Consortium member in the state of South Carolina.
"What dictates quality of care and outcomes is not only what resources you have, but also how quickly you can bring those resources to bear,” explained Houston. “Time to treatment is critical. At MUSC, we have the whole gamut of options, but what matters most is getting these interventions to the patient quickly. With massive PE, every hour increases the chance of death."
The MUSC PERT program provides a one-stop, multidisciplinary team of experts who can respond with the full spectrum of therapeutic options for patients with acute PE – no matter what hospital service is caring for them. The PERT can consult and generate a patient-specific plan much more quickly than if multiple, independent specialists had to be contacted individually for a consult.
In its first three years, the MUSC PERT has been activated more than 200 times. "When PE is diagnosed, a call goes out to the PERT. We often get calls from the ER (emergency room) which uses the PERT to help classify and manage patient risk," said Paoletti. Outside hospitals also call MUSC's PERT. "A lot of community hospitals only have the ability to do anticoagulant therapy or thrombolytics–and sometimes they aren't comfortable managing a high risk PE with thrombolytics. They often consult and send patients to us if they're stable enough to transport.”
A recent case illustrates the impact of the team's rapid and thorough response. A young woman who had developed preeclampsia during pregnancy, underwent a scheduled delivery at 37-weeks of gestation. During the delivery, she experienced difficulty breathing and a Cesarean-section was performed. After delivering a healthy baby girl, the mother's condition continued to decline, and she was transferred to the intensive care unit (ICU). Ultrasound and CT scans confirmed two large PEs, one in each pulmonary artery. Later that evening, the right side of her heart began to fail and she was ventilated.
At two in the morning, the PERT convened to discuss how to best treat this young mother. “She was in shock and dying in front of us,” said Dr. Thomas Todoran, associate professor in MUSC's Department of Medicine and co-leader of the MUSC PERT. The team decided to initiate extra-corporeal membrane oxygenation (ECMO) which pumps and oxygenates patients' blood, allowing their own organs to rest and recover. Houston explained, "ECMO is essentially a heart and lung machine. With PE, the lungs and the heart strain to function because they're blocked up with clots. ECMO allows the patient to continue having oxygenated blood flow but it's not widely available in South Carolina."
After three days on ECMO, her heart had not recovered, and the PERT chose to initiate catheter-directed thrombolysis. "We deployed tiny catheters into her heart and pulmonary arteries – where the clots were – and dripped a clot-busting medication (a thrombolytic and heparin) directly onto the clots to break them up. We also had an ultrasound at the end of catheter that was used to help fractionate the clots," said Houston. Approximately 24-hours after the procedure, she began to improve and was able to come off ECMO.
“She was very fortunate,” said Todoran. "Her access to a multidisciplinary team of specialists who responded rapidly and worked as a team, and the availability of ECMO probably saved her life."
Paoletti added, "In this case, the collaboration and teamwork were really essential. The OB-GYN, ICU fellow, interventional cardiologists and MICU attendings all rapidly worked together to determine the right diagnosis and the right treatment. That collaboration doesn't happen everywhere, and it's really hard to get it going. But the more we do it, the easier and better it becomes. They all worked really well as a team, and it saved this patient's life."
Indeed, this is the overall goal of the PERT Consortium as well as each individual PERT program. For its part, the MUSC PERT will continue working to improve PE treatment and research and to increase survival rates for patients who face this challenging condition.
[1]Dudzinski and Piazza. Multidisciplinary Pulmonary Embolism Response Teams. Circulation. 2016 ;133:98–103.
[2]Minges, KE, et al. National Trends in Pulmonary Embolism Hospitalization Rates and Outcomes for Adults ?65 Years of Age in the United States (1999–2010). Am J Cardiol. 2015;116(9):1436–1442.
[3]Ibid.
