Stent Thrombosis Linked to Uncovered, Malapposed Stent Struts

SAN FRANCISCO, CA - Patients who develop stent thrombosis after percutaneous coronary intervention are more likely to have uncovered and/or malapposed stent struts, according to data presented November 9, 2011, at the annual Transcatheter Cardiovascular Therapeutics scientific symposium.

For the prospective, multicenter, case-control MOST trial, Guido Parodi, MD, PhD, of Careggi Hospital (Florence, Italy), and colleagues assessed strut coverage and malapposition in 23 pairs of patients with stent thrombosis and matched controls. All subjects underwent optical coherence tomography (OCT) in the same lab during the same time period and at the same time intervals after stent implantation.

Baseline and procedural characteristics were similar between the 2 groups, except for a trend toward lower LVEF in stent thrombosis patients (P = 0.06). Among those with stent thrombosis, 8 received SES, 7 received PES, 3 received EES, and 5 received BMS; the pattern of stent use was the same in matched controls.

Uncovered stent struts were twice as prevalent among all patients with stent thrombosis as controls and almost 3 times more common in those with late or very late stent thrombosis. Uncovered stent struts also were seen more frequently in subacute stent thrombosis (table 1).

Table 1. Prevalence of Uncovered Stent Struts

Malapposed stent struts also were more prevalent among all patients with stent thrombosis and in particular those with late or very late stent thrombosis. However, for subacute stent thrombosis, malapposed struts were more common in controls (table 2).

Table 2. Prevalence of Malapposed Stent Struts

Residual platelet activity was assessed in 8 patients using the VerifyNow P2Y12 point-of-care assay (Accumetrics, San Diego, CA). DAPT discontinuation or high residual platelet reactivity was seen in all patients with stent thrombosis.

“Patients with stent thrombosis showed a higher rate of uncovered and malapposed stent struts as compared with controls irrespective of stent type and stent thrombosis timing,” Dr. Parodi concluded. “DAPT discontinuation or high residual platelet reactivity seem to be necessary co-factors. Thus, we can consider stent thrombosis a multifactorial event.”

Dr. Parodi added that he was surprised to find that malapposed struts occurred more frequently in controls than patients who experienced subacute stent thrombosis.

Source:

Parodi G. MOST: A prospective, multicenter case-control matched study investigating the causes of stent thrombosis using optical coherence tomography and platelet function testing. Presented at: Transcatheter Cardiovascular Therapeutics 2011; November 9, 2011; San Francisco, CA.

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