‘Surprising’ Uptick in Rates of Revascularization for In-Stent Restenosis

Despite advances in stent technology, an analysis of US Department of Veterans Affairs (VA) data indicates that rates of revascularization for in-stent restenosis (ISR) may be on the rise.

Stephen W. Waldo, MD (VA Eastern Colorado Health Care System, Denver, CO), the study’s lead author, told TCTMD the finding came as a surprise.

“We would imagine that with the increasing utilization of drug-eluting stents both inside and outside the VA, the treatment rates of restenosis would actually decline,” he said. “But in contrast, we determined that they are actually slightly increasing, or that there is at least a trend that has occurred over the last 5 years.”

Another novel finding of the study, which was published online June 28, 2017, ahead of print in Catheterization and Cardiovascular Interventions, is that mortality was lower in those treated with a DES versus either plain old balloon angioplasty (POBA) or a BMS (HR 0.73; 95% CI 0.64-0.83), something Waldo said hasn’t been demonstrated previously.

Provides Support for DES as Primary Method

The data come from the Veterans Affairs Clinical Assessment and Tracking (VA CART) program and include 6,872 mostly male patients who underwent PCI between 2006 and 2014 then subsequently required revascularization for ISR. They accounted for 10.5% of all patients in the database who underwent PCI during that period.

The proportion of patients undergoing revascularization for ISR increased 0.28% per year over the study period, although the trend did not reach significance (P = 0.05).

Nevertheless, the researchers say the relatively high rate of restenosis—occurring in as many as one third of patients receiving DES within 10 years of their index procedure—“highlights the importance of identifying the optimal intracoronary treatment modality to improve clinical outcomes for this population.”

In addition to the survival benefit of DES for restenosis, which was seen in propensity matching of 2,796 patients who received DES and 1,398 who received non-DES therapies, there also was less TVR among those treated with DES (HR 0.62; 95% CI 0.51-0.76).

Waldo said the data provide support for consensus opinion and guidelines that DES are the ideal choice for restenosis, and may have important implications for ongoing research.

ISR ‘Becoming a Problem’

The largely male population of the VA database limits the generalizability of the findings to more diverse populations. Another major limitation is that because the authors grouped patients undergoing revascularization for ISR together, it is unclear what percentage were originally treated with BMS or DES, and how many of the DES were first-generation devices.

“The majority of them probably were first generation,” Kevin J. Croce, MD, PhD (Brigham and Women’s Hospital, Boston, MA), who was not involved in the study, told TCTMD. Despite some assumptions that the paper appears to make, he said it “highlights an important problem in the field” and supports the suspicion that there is potentially a slow-growing increase in ISR rates that is not confined to the VA. Recent data, he added, suggest that the cumulative rates of ISR have crept up worldwide, resulting in about 100,000 patients per year needing revascularization of a stent they had implanted within the previous 5 years. Many of these are experiencing ISR multiple times.

“At our institution we’ve brought our brachytherapy program out of mothballs, because we’re starting to see a large burden of drug-eluting stent-in-stent restenosis,” he said. “My sense is it’s becoming a problem for many centers.” Young age at index stenting and poor deployment or other technique-related issues stemming from the early DES era are some possible explanations for the increase, he said.

Another important issue raised by the paper is that DES for restenosis seem to be chosen over other methods for patients who are in better health overall, as supported by the fact that even after propensity matching of the VA CART patients, more of those who were retreated with a non-DES had PAD, A-fib, chronic renal disease, and congestive heart failure.

“This paper affirms the fact that POBA for ISR is a very imperfect therapy with certainly much higher TVR compared to DES,” he added. “We should be cautious [about choosing it] because patients are likely to come back with failures, and within the constraints of this study design it seems clear that those patients don’t do as well from a longevity standpoint.”