Percutaneous Vertebral Augmentation for Vertebral Compression Fractures: National Trends in the Medicare Population (2005-2015).

STUDY DESIGN: Retrospective analysis of Medicare data OBJECTIVE.: To analyze trends of vertebral augmentation in the elderly Medicare population in the context of evolving evidence and varied medical society opinions. SUMMARY OF BACKGROUND DATA: Percutaneous vertebral augmentation offers a minimally invasive therapy for vertebral compression fractures. Numerous trials have been published on this topic with mixed results. The impact of these studies and societal recommendations on physician practice patterns is not well understood. METHODS: The Centers for Medicare and Medicaid Services annual Medicare Physician Supplier Procedure Summary database was examined for kyphoplasty and vertebroplasty procedures from 2005 through 2015. Top provider specialties were determined based on annual procedural volume, and grouped into the three broad categories of radiology, surgery, and anesthesia/pain medicine. Data entries were independently analyzed by provider type, site of service, submitted charges, and reimbursement rates for interventions during the study period. RESULTS: Between 2005 and 2015 total annual claims for vertebral augmentation procedures in the Medicare population increased from 108.11% (37,133-77,276) peaking in 2008 and declining by 15.56% in 2009. Radiology is the largest provider of vertebral augmentation by specialty with declining market shares from 71% in 2005 to 43% in 2015. The frequency of vertebroplasty declined by 61.7% (35,409-13,478) from 2005 to 2015 with reduction in Medicare reimbursement. Annual volume of kyphoplasty grew by 18.3% (48,725-57,646) with significant increase in reimbursement for office-based procedures ($728.50/yr, P < 0.001, R = 0.69). CONCLUSION: The annual volume of vertebral augmentation declined in 2009 following two negative trials on vertebroplasty. Although these publications had a persistent negative impact on practice of vertebroplasty, the overall frequency of vertebral augmentation in the Medicare population has not changed significantly between 2005 and 2015. Instead, there has been a significant shift in provider practice patterns in favor of kyphoplasty in increasingly outpatient and office-based settings. LEVEL OF EVIDENCE: 3.

Rising Retrieval Rates of Inferior Vena Cava Filters in the United States: Insights From the 2012 to 2016 Summary Medicare Claims Data.

BACKGROUND: To determine recent inferior vena cava filter (IVCF) retrieval volumes and rates in the Medicare population. METHODS: The summary Medicare claims data were searched for the years 2012 to 2016 to identify the frequency of IVCF placements and retrievals. The new Healthcare Common Procedure Coding System code for filter retrieval introduced in 2012, 37193, was used to track filter retrievals. Trends in number of IVCF placements and retrievals over the study period were evaluated, both of which were further stratified by physician specialty and site of service. Aggregate and compound annual growth rates for retrievals were also computed. RESULTS: A total of 255,034 filters were placed over the study period, with the filter placement volume declining from 61,889 in 2012 to 38,095 in 2016. Filter retrievals, however, increased from 4,327 in 2012 to 8,405 in 2016. The net filter retrieval rate per annual filters placed increased from 6.9% in 2012 to 22.1% in 2016, yielding an average filter retrieval rate and compound annual growth rate of 11.6% and 18.1% respectively. Radiologists placed and retrieved the majority of filters (60.4% placed, 63.5% retrieved) compared with nonradiologists. The inpatient setting was the dominant site for filter placement compared with the outpatient setting for filter retrieval across all years and specialties. CONCLUSIONS: Since introduction of the unique Healthcare Common Procedure Coding System code for IVCF retrieval in 2012, IVCF placements in the Medicare population have been declining and net retrieval rates have risen. Radiologists continue to place and retrieve the majority of filters.

Hemodialysis Access Maintenance in the Medicare Population: An Analysis Over a Decade of Trends by Provider Specialty and Site of Service.

PURPOSE: To evaluate annual national trends in hemodialysis access maintenance procedures in the Medicare population by specialty and setting. METHODS: Medicare Physician Supplier Procedure Summary Master Files between 2005 and 2015 were analyzed for procedure codes of hemodialysis access angiography and percutaneous thrombectomy. Using physician specialty codes, component procedure volume for endovascular services were queried for radiology, medicine, and surgery. Data entries were analyzed by provider specialty and place of service. Average submitted and allowed charges per intervention were extracted. Linear regression modeling was used to identify trends in number of and allowed charges by specialty and practice setting. RESULTS: Between 2005 and 2015, the frequency of dialysis access angiography for Medicare fee-for-service beneficiaries increased by a total of 74.71% (211,181 to 368,955). Specialty-specific analysis demonstrated volume increases of 220.21% (22,128 to 101,109) for surgery, 249.02% (32,690 to 114,094) for medicine, and 2.81% (135,564 to 139, 367) for radiology. By 2015, an increased trend from hospital-based to non-hospital-based procedures associated with significantly higher reimbursement rates to providers (+18,798 non-hospital-based cases/year, $46.95/year, P ≤ .001) was also observed, with medicine performing the highest volume of non-hospital-based procedures. In this period, there was also a modest total overall increase of percutaneous thrombectomy procedures by 7.75% (61,485 to 66,250). CONCLUSIONS: The frequency of endovascular hemodialysis access maintenance procedures in the Medicare fee-for-service program has increased from 2005 to 2015, with the majority market share transitioning from radiologists to non-radiologists. Similarly, most access maintenance in this time period changed from hospital-based to non-hospital-based interventions.

Prevalence, presentation, and endovascular management of hemodynamically or clinically significant arterio-portal fistulae in living and cadaveric donor liver transplant recipients.

PURPOSE: To compare the prevalence (cadaveric vs. living donor transplants), clinical features, and the effectiveness of endovascular management of significant arterio-portal fistulae (APF) in liver transplant recipients. METHODS: A retrospective audit of liver transplant recipients in two institutions was performed (1996-2009). Significant APF were included and were defined as symptomatic and/or hemodynamically significant (causing graft dysfunction and/or having abnormal Doppler findings in the portal vein). Patients with significant APF were evaluated for presenting symptoms, imaging features, size/branch order portal vein involvement, and effectiveness of the endovascular management (coil embolization). RESULTS: Four significant APF were found in 1992 (0.2%) liver transplants. Two were symptomatic and two were asymptomatic but were hemodynamically significant with liver function test abnormalities. All four APF were found in cadaveric donor graft recipients (0.23%, N = 4/1753) and none in 239 living donor graft recipients. However, there was no statistical difference between cadaveric and living donor graft recipients (p = 1.0, odds ratio = 1.23). Coil embolization was technically and clinically successful in all 4 without complications and causing normalization of the abnormal Doppler findings. CONCLUSION: Significant APF are a rare diagnosis (0.2% of transplants). Coil embolization is a safe and effective treatment option for APF in transplants.

In vitro assessment of aortic stent-graft integrity following exposure to Onyx liquid embolic agent.

PURPOSE: Endovascular stent-grafts are increasingly being used for treatment of abdominal and thoracic aortic aneurysms. Postprocedural complications include development of endoleaks. Recently, an embolic agent known as Onyx has been employed to treat type II endoleaks. Onyx is a biocompatible copolymer dissolved in dimethyl sulfoxide (DMSO). Although DMSO is known to damage some angiographic catheters, little is known concerning whether this compound damages stent-graft material. The current study was undertaken to directly explore this issue. MATERIALS AND METHODS: Four stent-grafts were evaluated: the Excluder, Zenith, AneuRx, and Talent. Stent-grafts were incubated for 24 hours at 37 degrees C under each of the following conditions: DMSO alone, 50/50 mixture of DMSO/Onyx, mixture of 1 part 50/50 DMSO/Onyx and 9 parts whole blood, and untreated control. Stent-grafts were microdissected into 15-mm sections, after which they were evaluated with scanning electron microscopy. RESULTS: No appreciable differences between stent-grafts exposed to DMSO and untreated controls were seen. Although liquid embolic agent was seen coating stent-grafts exposed to a 50/50 mixture of DMSO and Onyx, no evidence of fiber breakdown was noted. Stent-grafts exposed to DMSO/Onyx/whole blood demonstrated a thin coating of clot and Onyx without visual evidence of fiber compromise. CONCLUSIONS: The current study provides compelling evidence that short-term exposure of endograft material to DMSO, DMSO/Onyx, or DMSO/Onyx/whole blood is not associated with acute structural compromise of four commonly used aortic endografts. Future in vivo studies will help to further establish the safety of this agent.

Assessment of inter- and intraobserver agreement between intravascular US and aortic angiography of thoracic aortic injury.

PURPOSE: To compare inter- and intraobserver agreement at thoracic aortic angiography with that at intravascular ultrasonography (US) in the work-up of patients suspected of having thoracic aortic injury. MATERIALS AND METHODS: Three blinded readers performed a retrospective review of 95 thoracic aortic angiograms and 23 intravascular US images obtained in patients suspected of having traumatic aortic injury. Inter- and intraobserver agreement in the interpretation of the thoracic aortic angiograms and intravascular US images were determined by using Cohen kappa statistics. In addition, differences among demographic groups were evaluated by using bivariate analysis. RESULTS: Interobserver agreement was lowest in the interpretation of indeterminate angiograms (kappa = 0.55) and highest in the interpretation of determinate angiograms (kappa = 0.71). In contrast, interobserver agreement in the interpretation of intravascular US images was excellent. For all groups, intraobserver agreement in the interpretation of aortic angiograms was substantial and overall agreement was good (kappa = 0.88). Intraobserver agreement in the interpretation of intravascular US images was excellent (kappa = 1.00). Differences among demographic groups were not found to be significant. CONCLUSION: Intravascular US is an adjunct to aortic angiography and yields excellent overall inter- and intraobserver agreement. Subgroups of patients who are suspected of having aortic injury and have indeterminate angiograms may benefit from undergoing intravascular US.