Cath Lab Digest

The superficial femoral artery (SFA) data got another boost from the Zilver trial (Cook Medical, Bloomington, Indiana) this past month. The data presented at the SCAI meeting showed continued patency of the stented segments at 24 months compared with the percutaneous transluminal angioplasty (PTA) arm. At 12 months we recall that the Zilver result had a primary patency of 83% to 78% depending on the hard 12-month or 13-month endpoint. The optimal PTA had a primary patency of 64% in that time period. The suboptimal PTA had a second randomization to BMS Zilver (Cook Medical) versus the PTX Zilver (Cook Medical). There was a clear advantage of the drug to this cohort as was seen in the primary group receiving the drug. The “event free survival” 2 year metric presented at the SCAI meeting was 86.6% versus 77.6% (Zilver PTX compared with PTA alone) in the 56 patients followed. Further, if the metric used was primary patency, the Zilver stent group at 2 years was 75% versus 58% for the PTA arm.

What does this mean? Well, I bet that many fellow plumbers suggest that stenting clearly is the victor to the outcome in the patients with SFA disease. In fact, the outcomes suggest an overall reduction of 50% when compared with PTA for the stenting benefit. These are clearly important improvements in our scientific data. What is interesting is the 2-year patency of nearly 60% for the PTA arm. The optimal PTA arm is unknown as this cohort is a random sample of the cohort and not the entire cohort. Would we think that the 2-year patency of a PTA arm of a study would be the same patency at 2 years that the 2-year outcomes of stenting were at with Schillinger's manuscript? Indeed, at a metric PSVR of only 2.0 is remarkable.

When we consider the clinical benefit of the outcomes, we see the clear discrepancy of the primary patency from the clinical durability. The outcome of the PTA arm was nearly 78% at 2 years despite a primary patency of 58%. Again the FDA is trying to understand this difference and ask the question, does clinical patency trump primary patency for a clinical syndrome of claudication? I think if anyone can come up with a good surrogate endpoint that encompasses the clinical with the anatomic it would be exceedingly useful. One can argue that a PTA result would engender the same clinical benefit to the patient as a stenting result with or without a drug attached.

It remains a brave new world for the peripheralist — real science to contend with and discuss. The best benefit is that our patients now can make some informed decisions not left to any single center study or “in my hands my results have been” approaches to patient care. Let’s discuss this further next month and at that time let’s see what we think about single center studies and their outcomes on real work patients.

Reference

1. Schillinger M, Sabeti S, Loewe C, et al. Balloon Angioplasty versus Implantation of Nitinol Stents in the Superficial Femoral Artery. NEJM 2006;354:1879-1888.

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Dr. Garcia received his B.A. and M.D. degrees from the University of Arizona. He was an intern and resident at Parkland Memorial Hospital, University of Texas at Southwestern in Dallas, Texas. He received his training in cardiology at the University of Iowa Hospitals and Clinics in Iowa City, Iowa, and as an interventional cardiologist at the Beth Israel Deaconess Medical Center, Harvard Medical School. Further, he received his peripheral vascular training at St. Elizabeth’s Medical Center, Tuft’s University, Boston, Massachusetts. He then served as the Chief of Vascular Medicine and Peripheral Vascular Interventions for the Florida Heart Group in Orlando, Florida. Dr. Garcia returned to Harvard’s Beth Israel Hospital as a full-time interventional cardiologist and Director of the Peripheral Cardiovascular Program and Peripheral Interventions at the Beth Israel Deaconess Medical Center as well as the Director of the Interventional Fellowship Program. This program developed into one of the busiest in the city of Boston, performing over 600 peripheral procedures per year.

Dr. Garcia has now returned to St. Elizabeth’s Medical Center as Chief of the Section of Interventional Cardiology and as Associate Director of the Vascular Medicine Program. Dr. Garcia’s work has largely focused on arterial occlusion-reperfusion models and the efficacy of therapeutic modalities or interventions with regard to free radical generation or endovascular stenting outcomes. Dr. Garcia continues his research interests in a wide variety of studies including acute MI studies, unstable angina studies, interventional trials, peripheral interventional trials, angiogenesis trials, imaging modality studies, and numerous device trials for both the coronary and peripheral circulations. His work has been presented in numerous manuscripts, abstracts, textbooks and textbook chapters.