The Society for Cardiovascular Angiography and Interventions (SCAI), an independent organization for interventional medicine, is strongly urging doctors to inform patients about a new study that found a markedly higher death risk following use of stents and medical balloons containing the drug paclitaxel above the knee in the legs.

Paclitaxel is a drug coating commonly applied to medical devices that are used to open blood vessels in the legs. The drug is used to cut down on the risk of vessel re-closure. But a metaanalysis in the December Journal of the American Heart Association found that patients with the drug-coated devices had a 93 percent higher relative risk of death after five years later than patients in control groups who didn’t get paclitaxel.

On Friday, the SCAI published a statement that considered new evidence presented by the medical device companies at the LINC conference in Germany this week, as well as the limitations of JAHA study. 

The SCAI, like the U.S. Food and Drug Administration, judged that the evidence known today still favors using the devices. But patients should be informed, and any adverse events involving paclitaxel devices in the legs should be reported.

“At present, SCAI concurs with FDA that the benefits of paclitaxel devices continue to outweigh any potential risks,” SCAI President Dr. David A. Cox said in the statement Friday. “However, we strongly encourage our members to discuss the findings of the metaanalysis with their patients and to report any safety concerns to FDA.”

A research team based in Greece examined 28 randomized controlled trials evaluating 12 different drug-coated balloon or drug-eluting stents that contained paclitaxel. After five years, 14.7 percent of the patients who got paclitaxel devices and 8.1 percent of the non-paclitaxel patients had died. Those findings were based on 863 patients in the three studies that had five full years of data.

Two-year data, for 2,316 patients in 12 studies, found a 68 percent relative increase in mortality risk. There was no difference in mortality recorded at one year. The findings do not apply to paclitaxel devices used for coronary artery disease, only those for peripheral artery disease above the knee in the legs. Devices studied included Cook Medical's Zilver PTX stent, Becton Dickinson's Lutonix drug-coated balloon, Philips' Stellarex drug-coated balloon, and Boston Scientific's Ranger drug-coated balloon.

Since the study used aggregate trial data, and not patient-level data, it was not possible to isolate the individual patients who died and track their causes of death and health histories. Many more papers are expected to published on the topic in the near term.

Although it’s possible that sicker patients ended up in paclitaxel groups, physicians say randomizing patients inside clinical trials is intended to prevent that kind of selection bias.

The SCAI letter Friday says although the JAHA study’s methods are “fairly appropriate,” the organization still considers the finding of higher death risks to be theoretical.

“It is important to note that SCAI believes the associations are hypothesis generating and require further investigation with patient-level data,” the group said.

Asked whether it is still ethical to randomize patients to paclitaxel-treatments in ongoing studies for periperhal artery disease, Dr. Mehdi Shishehbor, chairman of the SCAI Vascular Disease Council, said that it is still ethical to do so.

"Based on the FDA's recommendations, multiple patient level large analysis at LINC this week, and lack of mechanistic association between these devices and late mortality I believe it is ethical," Shishehbor said via email Friday. "However, physicians should certainly notify their patients of the meta-analysis and the FDA position, including recent data that was presented at LINC."

For now, some hospitals are backing away from using the devices in routine practice or in clinical trials. Others are deciding on a case-by-case basis whether the benefits outweigh the risks. The FDA has an open investigation into the matter.

Peripheral artery disease (PAD) is a relatively common condition in which blood vessels in the legs become blocked, and can lead to limb amputation if severe enough. It affects more than 200 million worldwide, including more than 8 million people in the United States.

Devices to treat PAD are considered a fast-growing market in the medical device world. Medtronic’s In.Pact Admiral drug-coated balloon, for example, is thought to generate more than $200 million a year in sales. Medtronic has examined its internal data on the device and found no results to support the JAHA findings of increased mortality.

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To read more, follow all of the Star Tribune’s coverage of the debate over paclitaxel use in the legs.

On Jan. 10, the Star Tribune reported on device makers’ public reactions to the JAHA study during presentations to investors at the J.P. Morgan Healthcare conference. On Jan. 17, we reported that the FDA was opening an investigation despite the ongoing government shutdown. On Jan. 21 we reported that hospitals were taking different approaches to deciding whether to keep using the devices. On Jan. 22, we reported on the data that the medical device makers presented to bolster their cases for continued support of the devices.

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