Journal of Invasive Cardiology

Study limitations. First, this study is not a randomized trial; therefore, the results may be confounded by other factors. Although this is unlikely to occur, given the broad spectrum of characteristics evaluated in our study and which were taken into account by the propensity score matching, we cannot exclude residual confounding by unmeasured factors.³³

Moreover, the two consecutive series compared in the present study are not contemporary, but MC cases were collected in a period immediately antecedent to the adoption by our cath lab of a policy of systematic AS use. Our intention was to avoid a source of selection bias, as after AS introduction in our institution, MC was reserved for cases with angiographic contraindications to VCD. The comparison of non-contemporary cohorts can introduce bias due to changes in therapeutic practice over time. However, the rates of use of antiplatelets, anticoagulants, and their combinations, as well as the rates of PCI, were similar in the two groups. Moreover, after propensity score matching, groin hematomas remained the most frequent complication after MC and retroperitoneal bleeding the leading cause of trouble after AS deployment.

Another limitation could arise from the use of different VCDs, namely Angio-Seal STS and the novel Angio-Seal Evolution. However, subgroup analysis did not provide different results in comparison to the overall population analysis (data not shown), even if without sufficient statistical power due to the small number of events in subgroups.

Finally, the definition of “large groin hematoma” has been a subject of debate and the choice of a cut-off of ≥5 cm, as well as the methods of hematoma measurements, could be questionable. In a meta-analysis by Nickolsky et al,²⁰ the presence of a very wide-ranged criteria for the definition of groin hematoma was remarked and authors did not consider groin hematoma as a primary endpoint to avoid bias. Thus, in the present study, the cut-off was chosen at 5 cm, as in a large study by Bangalore et al.²²

Conclusion

Our study demonstrated that AS and MC were associated with different types of vascular complication, with a higher prevalence of retroperitoneal bleeding needing transfusions after AS deployment. However, hospital discharge was more delayed after MC, probably related to a higher incidence of pseudoaneurysms and the consequent surgical treatment. Comparison between strategies for achieving hemostasis after transfemoral procedures should take into account the different logistic and economic burdens imposed by different vascular complications.

Acknowledgments. We gratefully acknowledge the efforts of Maria Grazia D’Ulisse, Anna Federzoni, Chiara Clementi, Maria Teresa Bausani, Adele Mandrino, Pierangelo Rizzotti, and Roberta Sandri for their expertise and support in the cath lab and data collection.