Background Small vessel coronary artery disease (CAD) is frequently seen in coronary angiography and is associated with an increased risk of lesion failure and restenosis. Treatment strategies of small vessels are up to date not standardized while having drug eluting stents (DES) or drug coating balloons (DCB) as possible means of treatment.

Purpose We aimed to conduct a meta-analysis to evaluate treatment strategies and outcomes in small vessel CAD.

Methods Comprehensive literature search was performed for studies reporting treatment strategies of small vessel CAD with a reference diameter ≤ 2,8 mm using Pubmed, EMBASE, MEDLINE and Cochrane library databases. Clinical outcomes were defined as target-lesion revascularization (TLR), all-cause death, myocardial infarction (MI) and major cardiac events (MACE). Studies directly comparing treatment strategies were combined using meta-analysis techniques. In particular, the odds ratio (OR) was used for comparison of outcomes. Combination of clinical endpoints and risk factors from single-arm studies followed a meta-analytic approach based on comparison of measures by means of their corresponding 95% confidence interval (CI). Non-overlapping CIs may be interpreted as an indication of a non-existing difference.

Results 35 eligible studies with a total of 31.795 patients with small vessel CAD were included in the present analysis. Among those, 28.147 patients were treated with DES (24 studies) and 3.648 patients with DCB (17 studies). Common baseline characteristics were equally distributed in the different studies. TLR rate was 4% in both treatment strategies (0.04; 95%-CI 0.03-0.05 [DES] vs. 0.03-0.07 [DCB]). MI occurred in 3% of patients receiving DES and in 2% treating with DCB (0.03 [0.02-0.04] vs. 0.02 [0.01-0.03). Mortality rate was 3% in the DES group (0.03 [0.02-0.05]) compared to 1% in the DCB group (0.01 [0.00-0.03]). 9% of patients with DES developed MACE versus 4% of patients with DCB (0.09 [0.07-0.10] vs. 0.04 [0.02-0.08]). The results of the meta-analysis, including 16.782 patients from 8 studies (2.106 patients with DCB vs. 14.676 patients with DES) also indicated no statistically significant difference between DES and DCB strategies in rates of TLR (OR=1.21, 95%-CI 0.76-1.9, P=0.42), MI (OR=0.75, 95%CI 0.45-1.24, P=0.26], death (OR=1.10, 95%CI 0.91-1.34], P=0.31) and MACE (OR=0.93, 95%-CI 0.61-1.44, P=0.76).

Conclusion This large meta-analytic approach demonstrates similar clinical and angiographic results between treatment strategies with DES and DCB in small vessel CAD. Therefore, DES may be waived in small coronary arteries when PCI is performed with DCB.