Likelihood of Restenosis After Cardiac Stent Placement
The likelihood of restenosis after cardiac stent placement ranges from 17% to 32% with bare metal stents (BMS), while drug-eluting stents (DES) significantly reduce this risk to lower rates. 1
Restenosis Rates by Stent Type
- Bare Metal Stents (BMS): 17-32% restenosis rate 1
- First Generation DES: 65% reduction in restenosis compared to BMS 2
- Second Generation DES: Additional 33% reduction compared to first generation DES 2
Key Risk Factors for Restenosis
Patient-Related Factors:
- Diabetes mellitus: Increases restenosis risk by 86% 3, 4
- Prior history of restenosis: 3.4 times higher risk for subsequent restenosis 1
- Lower body mass index: Associated with higher restenosis risk in diabetic patients 3
Lesion-Related Factors:
- Small vessel diameter: Strongest predictor of restenosis with 79% increased risk in vessels 2.7mm vs 3.4mm 5, 2
- Left anterior descending (LAD) artery location: 3 times higher risk 1
- Complex lesion morphology: 35% increased risk 2
- Prior bypass surgery: 38% higher risk 2
Procedure-Related Factors:
- Multiple stents: Increases risk by 81-94% 4, 6
- Longer stent length: Each 10mm increase raises risk by 27% 7, 2
- Smaller post-procedure minimum luminal diameter: <3mm increases risk by 81% 4
- Higher residual percent diameter stenosis: Independent predictor 1
- Shorter time between initial and repeat procedures: When treating restenosis, intervals <3 months have higher recurrence (56% vs 37%) 1
Timing of Restenosis
Most restenosis occurs within 6 months after stent placement, which is why follow-up angiography is typically performed at this timepoint in clinical studies 1, 2.
Mechanisms of Restenosis
- Within the stent: Primarily due to intimal hyperplasia 1
- At stent margins: Combination of intimal hyperplasia and arterial remodeling 1
- Mechanical factors: Tissue prolapse between stent struts, particularly at articulation sites 1
Prevention Strategies
- Optimal stent selection: Match stent length to lesion length to avoid excessive stent length 7
- Drug-eluting stents: Recommended for higher-risk patients (diabetics, small vessels, long lesions) 7
- High-pressure inflation: Associated with lower late lumen loss 6
- Intravascular imaging guidance: Ensures complete lesion coverage and adequate stent expansion 7
Management of Restenosis
For patients who develop restenosis after balloon angioplasty or atherectomy, repeat intervention with intracoronary stents is reasonable if anatomically appropriate (Class IIa recommendation, Level of Evidence B) 1.
Clinical Implications
When counseling patients about restenosis risk, consider the combined effect of multiple risk factors. For example, a patient without any major risk factors may have a restenosis rate as low as 16%, while those with multiple risk factors (diabetes, multiple stents, small vessel) may have rates as high as 59% 4.
The likelihood of recurrent symptoms increases with each episode of restenosis, approaching 50-53% for patients undergoing a fourth percutaneous coronary intervention for a third episode of restenosis 1.