Chronic kidney disease (CKD) is linked to increased cardiovascular (CV) mortality and adverse cardiac events; however, traditional risk factors only partially explain this risk. Coronary microvascular dysfunction (CMD) is common in CKD, even in early stages, with previous research using coronary flow reserve (CFR) for diagnosis [ , ]. However, CFR was analyzed noninvasively in these previous studies. Furthermore, the index of microcirculatory resistance (IMR), measured invasively, offers a much more precise measure [ ]. We aimed to assess CMD prevalence in patients with CKD and angina with nonobstructive coronary arteries (ANOCA) compared to those without CKD using a more precise invasive assessment technique.