Why is this study important?

In-stent restenosis (ISR) is a known and important concern that can affect about 10% of percutaneous coronary interventions (PCIs) and has been shown to lead to more deleterious outcomes than de novo coronary stenosis. Hence, there is a need for alternative treatment strategies for ISR beyond plain-old balloon angioplasty (POBA) or committing patients to another layer of stent. 

What question was the study supposed to answer?

Recently, drug-coated balloon angioplasty (DCB) received FDA approval as a treatment strategy for ISR. However, randomized controlled trials (RCTs) have shown inconsistent results for DCBs, and no RCTs beyond three-year outcomes have been reported on coronary DCBs. In the presented observational study based on the Swedish Coronary Angiography and Angioplasty Registry (SCAAR) for patients undergoing PCI between June 11, 2013, and December 31, 2020, the authors looked into five-year outcomes (including target lesion revascularization [TLR], all-cause mortality, and myocardial infarction) of three treatment strategies for ISR: POBA, drug-eluting stents (DES), and DCB. 

What did the study show?

Among 7,987 patients with 9,304 segments with ISR, 2,865 of the segments were treated with DCB, 5,426 with DES, and 1,013 with POBA. The DES-treated patients were slightly older with: more smokers, ST-Segment Elevation Myocardial Infarction (STEMI), and proximal, complex lesions with larger diameter, but with less heart failure, kidney disease, hypertension, and hyperlipidemia. 

When comparing DCB to DES, DCB was associated with significantly higher rates of target lesion revascularization (TLR) (Unadjusted: HR 1.45 [1.27-1.65 95% CI, p<0.001]; Adjusted: HR 1.22 [1.07-1.41 95% CI, p=0.004]). No significant difference was observed for all-cause mortality or myocardial infarction. 

When comparing DCB to POBA, DCB was associated with significantly lower rates of TLR (Unadjusted: HR 0.81 [0.66-0.98 95% CI, p=0.034]; Adjusted: HR 0.62 [0.50-0.78 95% CI, p<0.001]), lower rate of all-cause mortality, and no significant difference of myocardial infarction rate.

Key takeaways

In this large segment-level analysis, the use of DCB during PCI of ISR showed better outcomes compared to POBA, which is in line with the recent AGENT IDE clinical trial (presented at TCT 2023). However, DES showed lower TLR than DCB, in line with the DAEDALUS trial with three-year follow-up. Balloon angioplasty with DCB holds promise as an alternative treatment strategy to DES for ISR, but there is a lack of randomized data ensuring the long-term safety of DCB. There were trends indicating that DCB might be equal to DES if two layers of stent are present.