BACKGROUND/RATIONALE:
Peripheral arterial disease (PAD) is an under-studied yet critical area of investigation of direct relevance to the mission of IHD-QUERI. PAD is characterized by atherosclerotic stenosis and occlusions in the peripheral arteries (e.g. 90% stenosis of the femoral artery in the thigh) and is a common condition affecting 12% to 29% of the elderly and as many as 8 million Americans. PAD is associated with significant morbidity, mortality, and resource use. The risk factors for PAD are nearly identical to risk factors for IHD, and the most common cause of death among PAD patients is IHD.

Two types of treatments address the direct affects of symptomatic PAD: (1) intervening on the arterial occlusion causing symptoms through peripheral vascular interventions (PVI) and (2) addressing the associated cardiac risk factors (e.g., hypertension and hyperlipidemia) through secondary prevention. In the U.S., there has been an explosion in the use of PVI, increasing 1000% from 1990-2000 and has outpaced investigations regarding its efficacy.

In addition, pharmacologic secondary prevention interventions such as anti-platelet drugs, anti-hypertensives and statin medications have been shown to reduce cardiovascular events in PAD patients and are strongly recommended by national guidelines but are underutilized (e.g. antiplatelet therapy and statin medications). Previous small studies outside the VA suggest that PAD patients receiving less than optimal medical treatment have increased events. To date, very little is known about the types of PVI procedures performed, indications, complication rates, subsequent secondary prevention and longitudinal outcomes among veteran patients with PAD.








OBJECTIVE(S):
1. identify practice patterns in the use of peripheral vascular interventions
2. identify practice patterns and potential gaps in the utilization of evidence-based medications in patients with PAD
3. determine the rate of complications associated with PVI and determine the long term morbidity (stroke, MI, repeat procedures and major amputations) and mortality in these patients.

METHODS:
We studied a convenience sample of 940 peripheral procedures entered into CART-CL between July 2005 and July 2010. Indications for the procedure, type of procedure performed, and complications were recorded. Patients were then followed longitudinally for the occurrence of a repeat procedure, myocardial infarction, stroke, amputation, or death. Statin and antiplatelet medication use was determined by VA pharmacy dispensing data. Cox proportional hazards modeling was performed to evaluate for independent factors associated with follow-up mortality.

FINDINGS/RESULTS:
Results
Nine hundred and forty procedures were performed over the study period. 242 non-lower extremity procedures were excluded from the primary analysis (Table 1). Of the 698 procedures, 400 (57.1%) were performed for claudication and 133 (19.1%) for critical limb ischema/non-healing wounds (CLI/NHW). These procedures occurred in 287 (80.2%) patients presenting with claudication and 71 (19.8%) patients presenting with CLI/NHWs. For all procedures performed for claudication or CLI/NHW, intraprocedural complication were infrequent occurring in 4.2% of patients. There were no procedural related deaths or emergent amputations. Four hundred sixty one (74.2%) lesions were treated with percutaneous transluminal angioplasty (PTA), 31 (4.9%) cryoplasty, 65 (10.4%) Silverhawk atherectomy, 22 (3.5%) Pathway atherectomy, 125 (20.1%) ballon explandable stent, and/or 254 (40.9%) self expanding stents. Only 17.8% of the patients undergoing PVI procedures were discharged on a Statin and even less (17.3%) patients were taking them at 6 months. More patients were on clopidogrel at discharge (46.8%) than at 6 months (11.2%). The survival was highest in patients who present with claudication, with a 1 and 3 year survival rates of 97.3% and 89.4% respectively versus 88.0% and 67.3% in patients who present with CLI/NHW (Log-Rank p<0.001). There were no significant differences in the rate of MI or stroke. Any vessel revascularization occurred in 22.6% of patients which did not differ by the presentation of claudication versus CLI/NHW (23.2% versus 20.0%, p=0.56). Predictors for post discharge mortality include age (RR 1.06; 95%CI 1.03-1.09), diabetes (RR 2.50; 95%CI 1.19-5.16) and CLI/NHW (RR 2.54; 95% CI 1.36-4.75).

IMPACT:
In summary, we analyzed data from a convenience sample of veterans undergoing peripheral vascular interventions to evaluate the indications, types of procedures performed, intraprocedural complications and follow-up endponts including medication prescriptions. Claudication was the most common indication and many different treatments were performed with a low overall complication rate. Mortality was high at three years affecting over 1 in 5 patients after their PVI procedure and over 1 in 3 patients with CLI/NHW. Furthermore, the overall use of statins and antiplatelet medications at discharge and 6 months was very low.

This study provides granular insights into the contemporary treatment and outcomes of Veteran patients undergoing PVI. Further study is critical to better understand the factors influencing treatment strategies in patient and anatomical subsets. Importantly, this study identifies an important gap in secondary prevention that can be addressed with further implementaton and intervention studies.

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External Links for this Project

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PUBLICATIONS:

Journal Articles

1. Maddox TM, Ho PM, Tsai TT, Wang TY, Li S, Peng SA, Wiviott SD, Masoudi FA, Rumsfeld JS. Clopidogrel use and hospital quality in medically managed patients with non-ST-segment-elevation myocardial infarction. Circulation. Cardiovascular quality and outcomes. 2012 Jul 1; 5(4):523-31. [view]
2. Xu S, Shetterly S, Powers D, Raebel MA, Tsai TT, Ho PM, Magid D. Extension of Kaplan-Meier methods in observational studies with time-varying treatment. Value in health : the journal of the International Society for Pharmacoeconomics and Outcomes Research. 2012 Jan 1; 15(1):167-74. [view]
3. Tsai TT, Messenger JC, Brennan JM, Patel UD, Dai D, Piana RN, Anstrom KJ, Eisenstein EL, Dokholyan RS, Peterson ED, Douglas PS. Safety and efficacy of drug-eluting stents in older patients with chronic kidney disease: a report from the linked CathPCI Registry-CMS claims database. Journal of the American College of Cardiology. 2011 Oct 25; 58(18):1859-69. [view]

Conference Presentations

1. Tsai TT. Beyond Quality Metrics: Cardiovascular Safety, Clinical Research and the Future of ACC National Cardiovascular Data Registries, FDA. Paper presented at: Cardiac Safety Research Consortium Thinktank Trans-Radial Education and Therapeutics Meeting; 2012 Jun 4; Silver Springs, MD. [view]
2. Tsai TT. CART-Peripheral: Why, How, When? Paper presented at: VA Optimizing Efficiency and Quality of Cardiovascular Care Annual Conference; 2011 Jul 1; Denver, CO. [view]
3. Tsai TT. Contemporary Incidence and Predictors of Acute Kidney Injury in Patients Undergoing PCI: Insights from the NCDR Cath-PCI Registry. Paper presented at: American College of Cardiology Annual Scientific Session; 2012 Mar 25; Chicago, IL. [view]
4. Tsai TT. Diffuse SFA/Popliteal Disease and Outcomes: Best Evidence Based Treatments. Paper presented at: Society for Cardiovascular Angiography and Interventions Annual Conference; 2011 May 4; Baltimore, MD. [view]
5. Tsai TT. Future of Registries and Observational PAD Data: Innovative Solutions to Vexing Problems. Paper presented at: Society for Cardiovascular Angiography and Interventions Annual Conference; 2012 May 11; Las Vegas, NV. [view]
6. Tsai TT. Getting Access to Data: Successful Examples from the NCDR. Paper presented at: American College of Cardiology Annual Scientific Session; 2012 Mar 24; Chicago, IL. [view]
7. Tsai TT. Lesion Definitions for Peripheral Vascular Interventions, FDA Headquarters. Paper presented at: Peripheral Academic Research Consortium Annual Meeting; 2012 Feb 7; Silver Springs, MD. [view]
8. Tsai TT, Ho M, Rumsfeld JS, Maddox TM, Rumsfeld JS. Long-term Risk of Bleeding and Impact of Non-Therapeutic INRs in Patients Discharged on Triple Antithrombotic Therapy after Hospitalization for Acute Coronary Syndrome. Poster session presented at: American Heart Association Annual Scientific Sessions; 2011 Nov 15; Orlando, FL. [view]
9. Tsai TT. Peripheral Arterial Disease and Critical Limb Ischemia (Live Case Demonstration). Presented at: Cardiovascular Research Technologies Annual Conference; 2012 Feb 10; Washington, DC. [view]
10. Tsai TT. Quality in the Peripheral Lab, Quality in the Catherization Laboratory. Paper presented at: American Heart Association Annual Scientific Sessions; 2011 Nov 15; Orlando, FL. [view]
11. Tsai TT. Radiation Safety and Radiation Reduction Techniques, University of Michigan Hospitals. Paper presented at: University of Michigan Cath Lab Annual Conference; 2012 May 7; Ann Arbor, MI. [view]
12. Tsai TT. Use and Effectiveness of Drug-Eluting versus Bare-Metal Stents in Saphenous Vein Bypass Graft PCI: Insights from the National VA Clinical Assessment, Reporting, and Tracking (CART) Program. Paper presented at: American Heart Association Annual Scientific Sessions; 2012 Nov 16; Orlando, FL. [view]
13. Tsai TT. Use and Effectiveness of Drug-Eluting vs. Bare Metal Stents in Saphenous Vein Bypass Graft PCI. Cardiac Risk Management. Paper presented at: VA HSR&D / QUERI National Meeting; 2012 Jul 19; National Harbor, MD. [view]

DRA: none
DRE: Prevention
Keywords: Cardiovasc’r disease, Prevention, Quality assessment
MeSH Terms: none