The interventionalist?s dilemma: innocent intimal hyperplasia or in-stent restenosis?
European Heart Journal
This editorial refers to "Alpha-adrenergic receptor blockade and hyperaemic response in patients with intermediate coronary stenoses" by A. De Bruyne et al. on page 2034 and "Utility of the fractional flow reserve in the evaluation of angiographically moderate in-stent restenosis" by Lopez-Palop et al. on page 2040 One of the remaining challenges in interventional cardiology is in-stent restenosis. In-stent restenosis is difficult to treat, often recurs, and may require repeated interventions
... ted interventions including bypass surgery and is therefore often frustrating for both the patient and the physician. If in-stent restenosis is severe and the relation with the patient's complaints or proven ischaemia is clear, there will be little discussion about the necessity to use the full armamentarium of the interventionalist to treat the stenosis, including brachytherapy, drug-eluting stents, and ultimately surgery if intervention fails. However, not infrequently patients return to the out-patient clinic weeks to years after stent implantation, with only mild or moderate in-stent restenosis, leaving unanswered the question whether this is a physiological degree of intimal hyperplasia or true restenosis which can be held responsible for complaints and/or ischaemia. In such cases, it is extremely important for the interventionalist to be sure that treatment is really indicated before opening Pandora's Box as outlined above. This is especially true in today's patient population, with often more (or even many) focal lesions or plaques within the coronary tree, often superimposed upon some degree of diffuse disease. It is not clear beforehand in such cases if it is the moderate in-stent restenosis or one of these other lesions which can be held responsible for (the recurrence of) complaints. How should we proceed in such patients? Just 'blindly' irradiate the presumed in-stent restenosis with the risk of activating a quiet non-significant lesion ? Place a drug-eluting stent within the previous stent with a recurrence risk of at least 20%? Or try to get some more specific information beforehand about the individual lesions? And how can such essential information be obtained? This issue is systematically addressed by the interesting study by Lopez-Palop et al., published in this issue of the Journal. 1 In this study, 65 in-stent restenotic lesions of moderate severity were studied. Fractional flow reserve (FFR) was measured in all of these lesions, and used for the decision of whether to treat. If FFR was <0.75, treatment by PCI was always performed; if the FFR was >0.75, no intervention was performed. The study by Lopez-Palop showed for the first time that quantitative coronary analysis was completely inappropriate for assessing the physiological significance of these moderate in-stent restenoses: in those vessels with a diameter stenosis >50%, half of the lesions were haemodynamically significant and the other half were not. More importantly, after 12 months follow-up, not a single adverse event occurred in relation to any of the deferred lesions. Had these lesions been treated instead of having measured fractional flow reserve, not only would a lot of money been wasted, but also repeated interventions with discomfort and potential risks for the patients would have been necessary within the next year in approximately 20% of them, no matter whether a drugeluting stent or brachytherapy had been used. 2 The ironic aspect is that neither the doctor nor the patient realise that the true, man-made restenosis in those 20% of patients is iatrogenic and could have been prevented by appropriate FFR measurement beforehand. Even though the number of patients is limited, the study by Lopez-Palop is convincing and extends our knowledge of moderate stenosis in native coronary arteries to in-stent restenosis.