The initial pattern of restenosis is the most important predictor of recurrent restenosis or the need of subsequent reintervention, according to the results of the DES-ISR study published in the February issue of the Journal of the American College of Cardiology: Cardiovascular Interventions. Compared with focal lesions, patients with occlusive and diffuse lesions saw the highest rates of restenosis.

Due to the widespread use of drug-eluting stents (DES), there are a large number of patients who present with stent failure, and the rates of repeat percutaneous intervention occur very frequently. However, the long-term effects of DES in-stent restenosis (DES-ISR) remain unknown.

To evaluate the long-term outcomes of DES-ISR, Azeem Latib, MB, of the San Raffaele Scientific Institute in Milan, Italy, and colleagues conducted a retrospective analysis of 481 lesions in 392 patients treated percutaneously between August 2002 and July 2007.

Of the 481 lesions, 305 were focal, 120 were diffuse and 56 were occlusive. Of the cohort, 65 percent of patients had angina or ischemia and 13 percent had acute coronary syndrome. The median time from DES implantation at the index lesion to treatment for DES-ISR was 224 days.

Patients with occlusive and diffuse lesions saw the highest rates of restenosis: 65.6 versus 45.8 percent. The same pattern of restenosis occurred in two-thirds of the restenotic lesions: two-thirds of focal lesions recurred as focal in-stent restenosis, two-thirds of occlusive in-stent reoccluded and two-thirds of diffuse lesions recurred as diffuse or occlusive restenosis.

While the researchers reported that there were no incidences of in-hospital deaths or periprocedural revascularizations, one-third of patients experienced a major adverse cardiovascular event during long-term follow-up.

However, the rates of target lesion revascularization (TLR) were highest for diffuse DES-ISR compared with focal DES-ISR: 28 versus 16.5 percent, respectively (per-patient numbers). These rates for the occlusive group were not “concordantly high, suggesting that many recurrent restenoses were not retreated,” the authors noted. In addition, diffuse restenosis and previous bypass surgery were both independent predictors of TLR.

Of the overall cohort, 47.6 percent of occlusive DES-ISR was retreated compared with 82.6 percent of focal and 84.2 percent of diffuse restenoses. Additionally, the authors noted that the presence of diabetes mellitus did not influence the rates of recurrent restenosis.

The researchers relayed three main findings:

• DES failure identified a group of patients who are at a high risk of future events after treatment, in particular repeat revascularization;
• The pattern of DES-ISR is an important predictor of the occurrence and pattern of recurrent restenosis, as well as the need for subsequent reintervention; and
• Treatment of DES-ISR with repeat DES implantation appears to be associated with a reduction in recurrent restenosis and does not seem to influence the risk of late stent thrombosis.

The researchers also said that CABG surgery could be an alternative treatment strategy for complex DES restenosis, particularly for those that occur in the left main or left anterior descending coronary arteries.

“The optimal percutaneous treatment of DES-ISR still remains unclear, that is, conventional angioplasty versus repeat DES for focal DES-ISR; or implanting a DES with a different drug (hetero-DES) versus the same drug (homo-DES),” the authors wrote.

“Our study does not clarify the appropriate strategy for treating DES-ISR, but it does reinforce the concept that when treating DES restenosis we should make every attempt to optimize the final result and not fail the second time.”

In an accompanying JACC editorial, Adnan Kastrati, MD, and Robert Byrne, MB, BCh, wrote: “The Achilles' heel of coronary stenting has long been the occurrence of arterial renarrowing or restenosis in the months after intervention.”

Kastrati and Byrne offered that the three principal options for treatment of DES resteonsis are: plain balloon angioplasty, DES and drug-coated balloon dilation.

In addition, results of the ISAR-DESIRE-2 (Intracoronary Stenting and Angiographic Results: DES for In-Stent Restenosis-2) trial showed that “implanting a DES that elutes the same class of drug as the failed initial DES or a switch to DES eluting another drug type are similarly efficacious.

“However, in light of encouraging data in BMS restenosis, the role of drug-coated balloon therapy in this therapeutic niche deserves further investigation," Kastrati and Byrne concluded.