From Skepticon sessions, to panel discussions, to debates, the Transcatheter Cardiovascular Therapeutics (TCT) conference was ablaze with differing opinions this Fall, although all in the name of medicine of course. Physicians battled it out behind conference room doors, sometimes defending unsupported or seemingly hopeless positions in order to acknowledge and present the existing counter arguments. One particularly lively discussion was that of below-the-knee (BTK) drug coated balloons (DCBs). The practice of using DCBs to treat BTK stenoses was brought into question in December 2013 with the interim analysis of data collected during the IN.PACT DEEP trial due to an apparent increased risk for major amputation in the DCB arm of the study.
The Amphirion DCB also failed to meet any of the trial's 3 primary endpoints for the DCB group, bewildering the company and physicians alike. However, similar to the general sentiment towards renal denervation, most practitioners seem to believe these negative results to be a consequence of a flawed study design. In the case of IN.PACT DEEP the sample population has been viewed as non-clinically relevant due to short lesion lengths, a low prevalence of CTOs, and an abnormally successful response to percutaneous balloon angioplasty (PTA) alone. These were argued as the reasons for the poor performance of the DCB group as compared to previous studies and the Amphirion failing to meet its primary efficacy endpoints.
Physicians are certainly concerned by the higher amputation rate seen in the DCB group but are not yet willing to give up on DCBs for BTK peripheral arterial disease (PAD). Inadequate and inconsistent foot care management was pointed at as a potential cause of increased amputations but must nonetheless be monitored very carefully in future studies. Many in attendance also raised the need to change the way we view and treat BTK PAD which differs from above-the-knee PAD in many ways including longer lesions, a greater degree of calcification, and a greater prevalence of diabetes and renal disease in this patient population.