Faculty Bibliography

PURPOSE/OBJECTIVE:To assess trends in inferior vena cava (IVC) filter placement and retrieval procedures in Medicare beneficiaries over the last two decades. METHODS:Using Physician/Supplier Procedure Summary Master Files from 1994 through 2015, we calculated utilization rates for IVC filter placement and retrieval procedures in Medicare fee-for-service beneficiaries. Services were stratified by provider specialty group and site of service. RESULTS:IVC filter placement rates increased from 1994 to 2008 (from 65.0 to 202.1 per 100,000 beneficiaries, compound annual growth rate [CAGR] +8.4%) and then decreased to 128.9 by 2015 (CAGR -6.2%). This decrease was observed across all specialty groups and sites of service. From 1994 to 2015, placement procedure market share increased for radiologists (from 45.1% to 62.7%) and cardiologists (from 2.5% to 6.7%) but decreased for surgeons (from 46.6% to 27.9%). Overall, procedures shifted slightly from the inpatient (from 94.5% to 86.5% of all procedures) to outpatient hospital (from 4.9% to 14.9%) settings. Between 2012 and 2015, retrieval rates increased from 12.0 to 17.7 (CAGR +13.9%). Retrievals as a percentage of placement procedures were similar across specialties in 2015 (range 13.0%-13.8%). CONCLUSION/CONCLUSIONS:Despite prior dramatic growth, the utilization of IVC filters in Medicare beneficiaries markedly declined over the last decade, likely relating to evolving views regarding efficacy and long-term safety. This decline was accompanied by several filter-related market shifts, including increasing placement by radiologists and cardiologists, increasing outpatient placement procedures, and increasing retrieval rates.

Acute pulmonary embolism (PE) is a major public health problem. It is the third most common cause of death in hospitalized patients. In the United States, there are up to 600,000 cases diagnosed per year with 100,000-180,000 acute PE-related deaths. Common risk factors include underlying genetic conditions, acquired conditions, and acquired hypercoagulable states. Acute PE increases the pulmonary vascular resistance and the load on the right ventricle (RV). Increased RV loading causes compensatory RV dilation, impaired contractility, tachycardia, and sympathetic activation. RV dilation and increased intramural pressure decrease diastolic coronary blood flow, leading to RV ischemia and myocardial necrosis. Ultimately, insufficient cardiac output from the RV causes left ventricular under-filling which results in systemic hypotension and cardiovascular collapse. Current prognostic stratification strategy separates acute PE into massive, submassive, and low-risk by presence or absence of sustained hypotension, RV dysfunction, and myocardial necrosis. Massive, submassive, and low-risk acute PE have mortality rates of 25%-65%, 3%, and <1%, respectively. Current PE management includes the use of anticoagulation alone, systemic thrombolysis, catheter-directed thrombolysis, and surgical embolectomy. This article will describe the current state of practice for catheter-directed thrombolysis and its role in the management of acute PE.

Acute pulmonary embolism (PE) is a leading cause of morbidity and mortality in the United States. PE associated with right ventricular strain, termed submassive or intermediate-risk PE, is associated with an increased rate of clinical deterioration and short-term mortality. Trials have demonstrated systemic thrombolytics may improve patient outcomes, but they carry a risk of major hemorrhage. Catheter-directed thrombolysis (CDT) may offer similar efficacy to and a lower risk of catastrophic hemorrhage than systemic thrombolysis. Three prospective trials have evaluated CDT for submassive PE; ULTIMA, SEATTLE II, and PERFECT. These trials provide evidence that CDT may improve radiographic efficacy endpoints in submassive PE with acceptable rates of major hemorrhage. However, the lack of clinical endpoints, long-term follow-up, and adequate sample size limit their generalizability. Future trials should be adequately powered and controlled so that the short- and long-term effectiveness and safety of CDT can be definitively determined.

Pulmonary embolism (PE) is a leading cause of morbidity and mortality worldwide. PE is a complex disease with a highly variable presentation and the available treatment options for PE are expanding rapidly. Anticoagulation (AC), systemic lysis, surgery, and catheter-directed thrombolysis (CDT) play important roles in treating patients with PE. Thus, a multidisciplinary approach to diagnosis, risk stratification, and therapy is required to determine which treatment option is best for a given patient with this complex disease.

The post-Pulmonary Embolism (post-PE) syndrome is being increasingly recognized as a long-term consequence of PE. Its most severe manifestation, chronic thromboembolic pulmonary hypertension (CTEPH), affects a small proportion of PE survivors. However, many more with less severe post-PE syndrome have reduced quality of life and functional capacity. The pathophysiology is incompletely understood, but involves unresolved pulmonary artery thrombi, right ventricular damage, and abnormal gas exchange. Treatment has only been established for CTEPH, and further studies are required to determine how less severe forms of the post-PE syndrome should be treated and if preventive strategies can reduce its incidence.

Patients who present with severe manifestations of acute venous thromboembolism (VTE) are at higher risk for premature death and long-term disability. In recent years, catheter-based interventional procedures have shown strong potential to improve clinical outcomes in selected VTE patients. However, physicians continue to be routinely faced with challenging decisions that pertain to the utilization of these risky and costly treatment strategies, and there is a relative paucity of published clinical trials with sufficient rigor and directness to inform clinical practice. In this article, using three distinct clinical scenario presentations, we draw from the available published literature describing the natural history, pathophysiology, treatments, and outcomes of VTE to illustrate the key factors that should influence clinical decision-making for patients with severe manifestations of deep vein thrombosis (DVT) and pulmonary embolism (PE). The results of a recently completed pivotal multicenter randomized trial are also discussed.