Comparing Specialties For Lower Endovascular Therapy
Endovascular lower-extremity revascularization by vascular specialists resulted in more transfusions and ICU use, as well as a longer hospital stay, more repeat revascularization procedures and amputations, and higher costs, compared with the same procedures performed by interventional radiologists, according to the results of a large database analysis of the Medicare 5% Standard Analytical Files.
Dr. Abdul M. Zafar of the Vascular Disease Research Center, Brown University Alpert Medical School, Providence, and his colleagues extracted claims for endovascularlower extremity revascularization (ELER) index procedures using Current Procedural Terminology (CPT) codes in the years 2005 through 2007.
They recorded the unique IDs of the 15,455 patients who underwent these procedures and for whom an inpatient or outpatient claim corresponding to the index procedure claim was available. This comprised all claims for percutaneous angioplasty, atherectomy, and stent implantation of lower extremity arteries.
The self-designated specialty code of the physician performing the procedure was used to determine specialist type: vascular surgeons (VS), interventional radiologists (IR); interventional cardiologists (IC); and "other."
After excluding patients who might have undergone hybrid procedures and those who underwent thrombolysis procedures in the same year as the index procedure, the final sample of 14,608 patients was analyzed for the following outcomes: length of hospital stay; use of intensive care unit (ICU) services; transfusions; in-hospital mortality; and repeat intervention (defined as any ELER, open lower-extremity revascularization, or amputation of the lower extremity).
The researchers built risk-adjusted logistic regression models by using maximum-likelihood estimates to compare various patient outcomes across different specialties, and they used a linear regression model employing ordinary least squares to analyze length of stay. Cost analysis was performed using a linear regression model based on the least-squares approach. All models were adjusted for age, sex, race, admission type (emergency or ambulatory), and other comorbidities using the Elixhauser comorbidities software available from the Agency for Healthcare Research and Quality. Other regression models that included the International Classification of Disease-9 code for disease severity were developed, but were less predictive and had lower R2 values, according to the authors. All logistic regression models passed the goodness-of-fit test at the 99% confidence level. In addition, linear regression models were also found to be satisfactory at the same level, according to the authors.
Within the study, there were 3,565 index procedures done by IRs; 5,489 by ICs; 5,358 by VSs; and 196 performed by "other" specialties (J. Vasc. Interven. Radiol 2012;23:3-9).
Dr. Zafar and his colleagues reported that VS outcomes were significantly worse than when the procedures were performed by an IR or IC. IRs had a 32% lower likelihood of ICU use (P less than .001) and a 37% lower likelihood of repeat lower-extremity revascularization or amputation (P less than .001) compared with VS. "Although statistical significance was not reached, both transfusion use and in-hospital mortality were 19% less likely after IRs performed procedures compared with VSs (P = .113 and P =.351, respectively)."
"Vascular surgeons were the only specialists with post-index procedure length of stay exceeding 3 days, significantly longer than observed for other specialties. The adjusted average 1-year costs per index procedure were 9% greater for vascular surgeons than for interventional radiologists ($19,012 vs. $17,640)," they said.
"The reasons for worse outcomes among VSs are not known, but may be related to insufficient training in catheter-based interventions as a result of the extensive time learning and practicing open surgical procedure compared with IRs and ICs, whose focus is catheter interventions," they said. "Medicare data indicate that patients who need lower-extremity endovascular revascularization services experience shorter hospital stays, require less transfusions and ICU services, have lower in-hospital mortality rates, and have much less chance of a subsequent revascularization or amputation within one year if treated by an IR rather than a VS," they concluded.
The study was supported by a grant from the Society of Interventional Radiology and internal funds from the Vascular Disease Research Center. One authors received research funding from Cordis/Johnson&Johnson, and Abbott Vascular and consulting for Microvention/Terumo.