Reply:

We are thankful for the profound comments of Wu and colleagues. Our study was, indeed, only a very small feasibility trial to evaluate the safety and efficacy of the 30-cm-long Proteus Embolic Capture Angioplasty (ECA) balloon; it was clearly not a clinical endpoint study.

It is well known that the rate of acute clinically relevant embolic events during peripheral interventions is low, and most of these events can be successfully managed during the index procedure, as shown by the study of Shrikhande and colleagues ¹ and Dieter and Najundappa. ² However, nothing is known about the clinical consequences of initially silent distal embolic events in patients undergoing repetitive redo procedures. In particular, patients at high risk for such redo procedures are the ones who have the highest peri-interventional embolic risk: long lesions, chronic total occlusions, and in-stent reocclusions. For clinicians, it is a well known phenomenon that peripheral outflow is progressively compromised in stepwise fashion with every additional complex procedure. Notably, the clinical implication of this finding is still uncertain. Considering the low incidence of clinically meaningful consequences of peri-interventional embolic events, it is very unlikely that such a large-scale trial evaluating the clinical benefit of any kind of embolic prevention device will be conducted in the near future.

However, as mentioned in our article, ³ there exists other meaningful endpoints that might be significantly affected by the use of protection devices, such as radiation time, amount of contrast potentially affecting renal function in patients with renal insufficiency, and, finally, treatment time, and with this catheterization lab time. We definitely agree with Wu and colleagues that a sufficiently powered, hard endpoint trial is mandatory before the general use of the ECA balloon can be recommended. Nevertheless, everything is a matter of cost: if the cost of an ECA balloon is not significantly higher than a 30-cm-long standard angioplasty balloon, the ECA balloon could be at least considered currently in lesions at high risk for distal embolization.