Stent Healing Delayed in Presence of Severe Coronary Calcification

By Will Boggs MD

December 23, 2019

NEW YORK (Reuters Health) - Severe coronary calcification is associated with delayed healing after implantation of newer-generation drug-eluting stents (DES), according to a new registry study.

"Even with our latest stent technologies, severe coronary calcification appears to have a large impact on the quality of healing that takes place," Dr. Aloke V. Finn from CVPath Institute, in Gaithersburg, and the University of Maryland School of Medicine, in Baltimore, told Reuters Health by email.

Previous studies have shown that severe lesion calcification is an independent risk factor for complications after percutaneous coronary intervention (PCI) and that severe calcification of the stented lesion is an independent predictor of poor clinical outcomes, including target lesion revascularization (TLR) and stent thrombosis (ST).

Dr. Finn and colleagues used data from the CVPath stent autopsy registry to investigate healing in severely calcified lesions in their study of 104 patients implanted with 134 newer-generation DES.

They classified the lesions into two groups: 46 lesions in 35 patients had severe calcification, and 88 lesions in 69 patients had nonsevere calcification (defined as none, mild, and moderately calcified lesions).

The prevalence of ST was significantly higher in patients with severe (4/46, 9%) versus nonsevere calcification (0%), and the prevalence of restenosis was nominally higher (17% vs. 7%; P=0.054), the researchers report in the European Heart Journal.

The percent of uncovered strut per lesion was significantly higher in those with severe calcification (2.4%) than in those with nonsevere calcification (0%). The same was true of the prevalence of severe medial tears (59% vs. 44%, respectively) and of sections with at least three consecutive struts in direct contact with surface calcified area (52% vs. 8%).

In multivariate analysis, independent predictors of delayed strut coverage included duration of implantation of six months or less, three or more consecutive struts on surface calcified area, strut malapposition and lack of severe medial tears.

The overall prevalence of neoatherosclerosis was significantly higher in the nonsevere-calcification group (44% vs. 24%), and there was a progressive increase in neoatherosclerosis in both groups with greater duration of implant.

Calcification of the neointima was a prominent feature of neoatherosclerosis in the severe-calcification group, whereas the presence of foamy macrophages in the neointima predominated in the nonsevere-calcification group.

"Physicians should not underestimate the impact that calcium has on influencing the vascular response to stenting," Dr. Finn said. "Those with heavy coronary calcium may be at a higher risk of stent thrombosis due to delayed healing, and these subjects would not be good candidates for short-term dual anti-platelet therapy."

"A better understanding needs to be brought forth about how to improve outcomes in patients with severe coronary calcium undergoing PCI," he said.

SOURCE: European Heart Journal, online December 5, 2019.