Formation of Calcified Nodule as a Cause of Early In‐Stent Restenosis in Patients Undergoing Dialysis

Abstract

Background Dialysis is an independent risk factor for in‐stent restenosis (ISR) after stent implantation in coronary arteries. However, the characteristics of ISR in patients undergoing dialysis remain unclear, as there are no histological studies evaluating the causes of this condition. The aim of the present study was to investigate the causes of ISR between patients who are undergoing dialysis and those who are not by evaluating tissues obtained from ISR lesions using directional coronary atherectomy. Methods and Results A total of 29 ISR lesions from 29 patients included in a multicenter directional coronary atherectomy registry of 128 patients were selected for analysis and divided into a dialysis group (n=8) and a nondialysis group (n=21). Histopathological evaluation demonstrated that an in‐stent calcified nodule was a major histological characteristic of ISR lesions in the dialysis group and the prevalence of an in‐stent calcified nodule was significantly higher in the dialysis group compared with the nondialysis group (75% versus 5%, respectively; P <0.01). On the other hand, the prevalence of an in‐stent lipid‐rich plaque was significantly lower in the dialysis group compared with the nondialysis group (0% versus 43%, respectively; P =0.03). In all cases with an in‐stent calcified nodule, the underlying calcification before stent implantation was moderate to severe. When tissue characteristics were stratified according to duration post–stent implantation, an in‐stent calcified nodule in the dialysis group was mainly observed within 1 year after stent implantation. Conclusions In‐stent calcified nodules are a common cause of ISR in patients undergoing dialysis and are observed within 1 year after stent implantation, suggesting different causes of ISR between patients undergoing dialysis and those who are not.

Calcified nodule: A rare but important cause of acute coronary syndrome with worse clinical outcomes

“…Like CN in native coronary arteries, the potential mechanisms of instent CN must be discussed. Nakamura et al reported histopathologic analysis of ISR lesions obtained by directional coronary atherectomy from hemodialysis patients and suggested that one of the potential mechanisms of in-stent CN is related to the protrusion of a CN (already present at the time of stenting) into the lumen through the stent struts [4]. In our institution, we have received over 1200 stents from 700 sudden death individuals for over 2 decades [5].…”

Very Early Progression of an In-Stent Calcified Nodule 2 Weeks After Drug-Eluting Stent Implantation in the Calcified Lesion

“…noted that the protrusion of a CN followed by a calcifying fibrin thrombus might cause an early (2-3 months) in-stent CN. 5 In the present patient, the fact that the in-stent CNs were detected only 2 weeks after the initial PCI indicates that the underlying mechanism is as follows: the underlying CNs (the necrotic core calcium fragments) were manifested as a protrusion due to the debulking by the atherectomy devices and mechanical injury by balloon dilatation and stent implantation, and it progressed in the subacute phase. The current case indicates that acute coronary syndrome due to the progression of in-stent CNs can occur even in the subacute phase (only 2 weeks after the initial PCI).…”

“…In addition, CNs have been reported to have a poor prognosis even after treatment, and around 78% of instent restenosis at CN lesions was caused by the formation of a protruding mass with acoustic J o u r n a l P r e -p r o o f shadowing rather than neointimal hyperplasia, which indicated that intrusion of the calcified nodule is the cause of in-stent restenosis after stenting a calcified nodule (4). Also, in-stent CNs are one of the mechanisms of in stent restenosis and were reported to be particularly common in dialysis patients (5); however, the mechanism has not been elucidated. Nakamura et al noted that the protrusion of a CN followed by a calcifying fibrin thrombus might cause early (2-3 months) in-stent CN (5).…”

“…Also, in-stent CNs are one of the mechanisms of in stent restenosis and were reported to be particularly common in dialysis patients (5); however, the mechanism has not been elucidated. Nakamura et al noted that the protrusion of a CN followed by a calcifying fibrin thrombus might cause early (2-3 months) in-stent CN (5). In the present patient, since the in-stent CNs were detected only 2 weeks after the initial PCI, the underlying mechanism would be as follows: the underlying CNs (the necrotic core calcium fragments) were manifested as a protrusion due to the debulking by the atherectomy devices and mechanical injury by balloon dilatation and stent implantation, and it progressed in the sub-acute phase.…”

Predictors of clinical outcome after rotational atherectomy-facilitated percutaneous coronary intervention in hemodialysis patients

“…Ann Palliat Med 2021 | https://dx.doi.org/10.21037/apm-21-1658 lipid-rich plaque was significantly lower in the HD group (0% versus 43%, respectively; P=0.03) (24). The calcified character of ISR in HD patients poses a great challenge in treatment.…”