More Angioplasties ≠ Better Results?

This summary from work published by Beth Israel Deaconess Medial Center's Sachs and coworkers in this month's Journal of Vascular Surgery courtesy of the folks at Medical News/MedPageToday:

By John Gever, Senior Editor, MedPage Today
Published: October 10, 2011
Reviewed by Robert Jasmer, MD; Associate Clinical Professor of Medicine, University of California, San Francisco and
Dorothy Caputo, MA, RN, BC-ADM, CDE, Nurse Planner
Percutaneous transluminal angioplasty (PTA) to treat vascular disease in the legs increased threefold from 1999 to 2007 and has overtaken peripheral bypass graft surgery in popularity, but whether patients have benefited from the trend remains uncertain, researchers said.

Data from the Nationwide Inpatient Sample program for those years indicated that inpatient mortality was slightly lower among PTA-treated patients than in those undergoing peripheral bypass graft surgery, but amputation rates were nearly double with PTA when used for critical limb ischemia, reported Teviah Sachs, MD, MPH, of Beth Israel Deaconess Medical Center in Boston, and colleagues.

Moreover, the average cost per procedure rose more steeply for PTA during the study period, such that by 2007, it cost more than bypass graft surgery, Sachs and colleagues reported online in the Journal of Vascular Surgery.

Action Points  

  • Explain that percutaneous transluminal angioplasty (PTA) to treat vascular disease in the legs has overtaken peripheral bypass graft surgery in popularity.
  • Note that although inpatient mortality was slightly lower among PTA-treated patients than in those undergoing peripheral bypass graft surgery, amputation rates were nearly double with PTA when used for critical limb ischemia.

Their data did not indicate when a procedure was a repeat in a previously treated patient, the researchers pointed out. As a result, they wrote, “the mortality benefit with PTA may be ultimately lost, and average costs elevated, if multiple interventions are performed on the same patients.”

The need for treatment of peripheral limb ischemia is clear. Some 4% of Americans develop claudication by middle age, and up to one-seventh of those older than 70 may have detectable atherosclerosis in leg vessels, Sachs and colleagues explained.

In turn, 1% to 2% of patients with claudication progress to limb threat (also known as critical limb ischemia) within five years, they noted.

The Nationwide Inpatient Sample database indicated that 563,143 procedures were performed to treat claudication or limb threat during the nine-year study period.

Of these, 38% were PTA, 50% were peripheral bypass grafts, 6% were aortofemoral bypass grafts, and the remainder had multiple procedure codes.

Over time, though, PTA gained dramatically in popularity: The annual number of procedures increased threefold, reaching more than 46,000 for claudication and nearly 20,000 for limb threat in 2007.

Peripheral bypass grafts, on the other hand, declined by about 40%, with fewer than 10,000 performed in 2007 for claudication and about 14,000 for limb threat.

Early in the study period, procedure costs were lower for PTA than bypass grafting, but that reversed by 2007. At that point, costs for PTA averaged $14,084 for claudication and $23,196 for limb threat.

Corresponding costs for peripheral bypass grafting were $12,681 for claudication and $22,910 for limb threat.

Of course, the cost increases and differentials would be acceptable if they came with improved outcomes, but Sachs and colleagues found that the data were equivocal on that score.

The Nationwide Inpatient Sample only had records of in-hospital mortality and amputation, an important limitation to the analysis.

These, at least, did not clearly favor one type of procedure over the other.

For PTA, rates of in-hospital mortality were 0.2% for claudication and 2.1% for limb threat, compared with 0.4% and 2.5%, respectively, with peripheral bypass grafts. Mortality rates were even higher for aortofemoral bypass, at 1.5% and 4.1%, respectively.

The mortality difference between PTA and peripheral bypass was significant in claudication (P<0.01) but not for limb threat.

In-hospital amputation rates, however, were markedly and significantly lower for peripheral bypass grafts when performed for limb threat: 3.9% versus 7% with PTA (P<0.01). There was no significant difference in amputation rate in patients with claudication (0.1% PTA, 0.2% peripheral bypass).

Amputation rates for aortofemoral bypass were 0.1% for claudication and 3% for limb threat.

One clear advantage for PTA was in duration of hospital stay. The mean was one day (SD 0.02) compared with 4.52 days (SD 0.3) for peripheral bypass graft and 5.88 days (SD 0.05) for aortofemoral bypass.

Also, more PTA patients were discharged to home versus another healthcare facility (80.2%) relative to patients receiving peripheral or aortofemoral bypass (55.2% and 73.9%, respectively, both P<0.01 relative to PTA).

Some of the differences in outcomes could be attributable to patients' clinical characteristics, which, in turn, may have influenced the selection of procedure.

Sachs and colleagues had only limited data to work with in assessing this possibility, mainly records of age, race, gender, and certain comorbidities.

Relative to peripheral bypass patients, those receiving PTA were significantly more likely to meet the following criteria:

  • Be female
  • Have hypertension
  • Have congestive heart failure
  • Have renal failure
  • Have diabetes
  • Be less likely to have chronic pulmonary disease

But other factors likely to influence procedure selection, such as the occluded segment length, were not available for analysis, Sachs and colleagues indicated. They also noted that some of the PTA procedures were probably performed as salvage efforts in preparation for below-knee amputations.

Also, the data did not indicate whether amputated legs were the same ones on which the procedures were performed. Conceivably, some amputations were on contralateral limbs.

“Even so, the relatively high rate of amputations seen with PTA in our study is worrisome and merits further investigation,” the researchers wrote.

They noted as well that, although the data did not indicate when procedures were repeats, it was likely that many PTA procedures were not the first that patients had received. Sachs and colleagues cited other studies indicating that more than 30% of patients receiving angioplasty as initial treatment require additional procedures.

“Therefore, costs for the individual patient … are likely higher than what we report, and percentage of amputations in the PTA group would also potentially rise.”

To clarify these issues, Sachs and colleagues recommended increased use of prospective registries, with more detailed information on patients, the procedures they receive, and post-discharge, as well as in-hospital events and outcomes.

The authors reported no external funding for the study.

They declared they had no relevant financial interests.

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