Pulmonary embolism (PE) is the third most common cause of cardiovascular death in the United States and remains the most common preventable cause of in-hospital death. One might think that, in 2017, such a life-threatening cardiovascular emergency would be managed by guideline-driven care based upon robust evidence gathered through clinical trials and large observational studies. Yet, unlike stroke and myocardial infarction (STEMI), a true consensus for best management of acute PE has not been reached.
Management of PE has received increasing attention recently at major cardiovascular meetings such as VEITH, TCT, and national and regional societies. This excitement has been driven by recent trial data demonstrating that right ventricular failure with an acute PE is associated with poor outcomes and rapid clot debulking can reduce mortality not only in patients with high risk (massive) PE but even in intermediate risk (submassive) PE.
Charles B. Ross, MD
Systemic thrombolysis has been the standard of care for higher risk PEs but multiple contraindications and high complication rates shifted care toward catheter interventions assumed to have a safer profile. The huge gap of past decades between therapeutic anticoagulation alone versus systemic thrombolysis or surgical pulmonary embolectomy has been filled with an array of catheter-based techniques. Contemporary management of intermediate and high-risk PE employs thrombolytic infusion catheters at the clot site with or without ultrasound technology, mechanical fragmentation, and aspiration/suction thrombectomy devices. These techniques may lack robust evidence supporting them, still their use has been exponentially growing over the past 2 years. Yet, there is no clear consensus guiding management. Who needs to be treated? What’s the best technique for any given patient? What are the therapeutic endpoints? A myriad of questions remain to be answered.
Uncertainty about best management for an individual patient with acute PE stimulated formation of a multidisciplinary, collaborative approach beginning in 2012 at Massachusetts General Hospital in Boston.
Efthymios D. Avgerinos, MD
This approach, led by Kenneth Rosenfield, MD, involved the formal development of a call team of various specialists who would be rapidly activated to develop a care plan for any patient with acute PE. The term “Pulmonary Embolism Response Team” (PERT) was coined by MGH pulmonologist Richard Channick, MD, and since then, the PERT approach has been adopted by more than 100 centers across the United States and internationally.
Rapid communication between frontline physicians who diagnose PE and those who can offer definitive management is the hallmark of the PERT approach. PERTs at both Piedmont Atlanta Hospital (care plan shown below) and the University of Pittsburgh Medical Center (UPMC) function similarly. Patients are triaged by a critical care pulmonologist. For those with massive PE (hemodynamically unstable), the emergency call center establishes a cellular link between the bedside emergency physician, triaging critical care pulmonologist, the PE interventionalist, cardiothoracic surgeon, and ECMO team. CTAs may be viewed electronically, management plans initiated, and teams rapidly mobilized. For patients with submassive PE, the triaging critical care pulmonologist initiates management discussion with the “PE interventionalist” on call. Patient presentation, physiologic data, biomarkers, and preexisting comorbidities are discussed. CTAs are viewed. Multiple treatment plans are considered from traditional medical management to catheter-based techniques for more peripheral emboli to surgical pulmonary embolectomy for centrally located thrombus. Treatment plans are influenced by factors such as patient age and comorbidity and are collaboratively tailored to each individual patient.
Management decisions for acute PE are driven by risk stratification. Most patients who present with PE are considered “low risk” for PE-related death and are managed with therapeutic anticoagulation. Five percent of patients present with massive PE characterized by shock and are at “high-risk” for PE-related death. These patients require intervention. Up to 40% of patients present with submassive PE. These patients are hemodynamically stable (not hypotensive) but have evidence on CTA or echocardiogram for right ventricular dysfunction and are at “intermediate risk” for PE-related death. This group is further stratified as intermediate low-risk vs. intermediate high-risk by biomarkers that indicate myocardial damage, primarily troponin and BNP. In this intermediate-risk or submassive group, intervention is more commonly offered to those patients stratified as intermediate “high-risk.”
Significant variability in the management of both massive and submassive PE patients beyond therapeutic anticoagulation, e.g., upon whom to offer intervention and how, is the point where a PERT may have greatest impact. Rapid, collaborative decision making between physicians/surgeons from multiple specialties offers hope for minimizing morbidity and achievement of best outcome.
Who is the “Pulmonary Interventionalist” and where does the contemporarily-trained vascular surgeon with catheter and critical-care skills fit into this new paradigm? The answer to this question depends on each individual institution.
At the University of Pittsburgh Medical Center and Piedmont Heart and Vascular Institute at Piedmont Atlanta Hospital, catheter-based intervention programs for PE were initiated by vascular surgeons. As their interest developed over time, interventional cardiologists joined th “PE Interventional” call as full participants in the PERT programs.
PE interventions at other institutions such as Emory Midtown Medical Center in Atlanta have been driven by interventional cardiology in partnership with cardiothoracic surgery. Still, at others, such as Miami Heart and Vascular Institute, vascular and interventional radiology has led the charge. PE intervention, not owned by any single specialty, has been taken on by those groups interested in answering the call. In the case of the two programs that we represent, it was our established involvement in major venous interventions that followed a natural progression to PE intervention.
Management of PE may be challenging. Multidisciplinary collaboration is key. Recognition of the importance of collaboration in moving the field forward (and saving lives) led Dr. Rosenfield and others to host the first PERT Consortium Meeting in Boston 2015. This clarion call was answered by 80 individuals representing 40 institutions.
In 2016, the PERT Consortium was incorporated, and in June 2016, more than 140 people from nearly 80 institutions attended the second annual meeting. We attended the meeting last June, and with concern we noted only a few vascular surgeons representing other institutions. A participant survey, later published in a letter in CHEST (December 2016), suggested little involvement of vascular surgeons in PERT programs. Was this an artifact based on a survey of “those registered in the PERT mailing list” or does this represent the true interest of vascular surgeons in managing PE in this country? Whether the meeting survey accurately reflects the current involvement of vascular surgeons in the care of PE or not, one thing is certain: Vascular surgical visibility, as a specialty, in PE is poor.
Failure to be involved in the PERT movement deprives patients of the experience of vascular surgeons and potentially threatens the venous intervention practice of nonparticipating surgeons. Forty percent or more of cases of iliofemoral venous thrombosis have associated PE. Vena cava thrombosis may present with PE. Inferior vena cava tumors such as leiomyomatosis may be mistaken for PE. It is foreseeable that PERT activation will represent the gateway to care for many of these patients, who may in turn receive their care from others new to the management of venous and VTE disease.
Participation in a collaborative decision among colleagues about the best way to treat an individual patient is a gratifying experience. When the treatment fits, relieving the struggle of a patient with an acute PE through catheter-directed thrombus dissolution and debulking represents an opportunity to save productive lives using techniques that lie within the skill set of the contemporarily trained vascular surgeon. A save in the case of a challenging PE can be every bit as rewarding as successful management of a ruptured aneurysm.
Even in metropolitan regions, patients with acute PE are underserved because specialized care is frequently unavailable or PE programs nonexistent. In communities and hospitals where vascular surgeons represent the lead interventionalists, involvement in this field might even be considered a solemn responsibility.
Vascular surgeons such as Peter Lin, MD, previously at the University of Texas in Houston, and the group led by Rabih Chaer, MD, at UPMC, have advanced the science of PE intervention over the past 7 years. It is time for more vascular surgeons to enter the field and embrace pulmonary interventions. To achieve this, we need to embrace collaboration with pulmonary and critical care as well as emergency medicine since these are the main referral specialties. We need to promote initiatives participating in our local PERTs or bringing specialists together to start one where nonexistent. There is no reason for exclusivity, and collaboration with other interventionalists is essential for smooth interspecialty relations, multidisciplinary approaches, and optimal outcomes.
Academic and large community vascular centers need to include the vascular surgeons’ role in their descriptions of their PERTs. Toward this direction the vascular division of UPMC is consistently presenting and publishing results and outcomes of PE catheter interventions; very recently a randomized trial (SUNSET sPE) comparing lysis outcomes with and without ultrasound acceleration has been launched by the UPMC PERT, led and coordinated by vascular surgeons, and has already stimulated national interest. Vascular surgeons at Piedmont Heart and Vascular Institute are participating in national clinical trials (OPTALYSE) and actively collaborating with other PERT programs to advance the management of acute PE in Georgia and the southeast. Both UPMC and Piedmont Heart and Vascular Institute are founding institutional members of the PERT Consortium.
The third annual meeting of the PERT Consortium will occur in Boston in June 2017. Vascular surgeons who attend will assuredly be welcome. Answer the call.
Charles B. Ross, MD, is chief, Vascular and Endovascular Services, Piedmont Heart Institute, Atlanta. Efthymios Avgerinos, MD, is associate professor of surgery, Division of Vascular Surgery, Heart and Vascular Institute, University of Pittsburgh Medical Center. They had no relevant disclosures.
