TLR - Target lesion recurrence
It may help to further define the problem with TLR if we use a hypothetical example of a new medicated stent inserted to open a single SFA lesion responsible for toe gangrene. If that stent keeps the stenotic lesion widely patent, it should be considered effective even if the patient ultimately requires an above-knee amputation. On the other hand if the stent occludes in the recovery room, yet the toe subsequently heals without any further intervention, that stent did not work. In the latter scenario the patient will not have had a revascularization and so will not be included with the patients requiring TLR. Thus the stent would appear to have had more clinical utility or to have been more”successful” than it really was. Similarly, TLR will not be negatively impacted when, as in some circumstances of stent occlusion, a patient decides to live with discomfort rather than consent to another procedure. Furthermore, investigators of that stent may have a perverse incentive after occlusion to minimize TLR by not performing another procedure. On the other hand a bypass of an artery with an open and functional stent would negatively impact TLR statistics for that type of stent. This may occur if the stented lesion was not the only cause of distal ischemia.What concerns me most about TLR, even more than its limited relevance, is that this statistic is used to support data that otherwise would not stand up to scrutiny. It is often included in trials where numbers are small or where Industry bias is obvious. Accordingly, I am hopeful that researchers seriously consider describing TLR as target lesion recurrence rates omitting target lesion revascularization from their presentations and manuscripts. If they insist on using this irrelevant statistic then they should provide information as to why the revascularization was performed.
Was it for lesion recurrence or failure to improve the indicated condition? If the lesion recurred but TLR was not performed, was that because recovery had been achieved despite restenosis of the target lesion? Was it because the patient was not offered further treatment? Perhaps the patient succumbed before TLR could have been provided?
I may be accused of being overly cynical, but it may have been because the patient had decided that the better part of valor would be to run away and join a witness protection program rather than take part in that clinical trial.
