Long-term clinical outcomes after angiographically defined very late stent thrombosis of drug-eluting stent.

Background: The advent of drug-eluting stent (DES) use has raised concerns regarding later occurring stent thrombosis, especially very late stent thrombosis (VLST), and little is known about long-term clinical outcomes after VLST occurrence.

Hypothesis: Long-term clinical outcomes after detection of VLST may be poor.

Method: We evaluated 3572 consecutive patients who received DES implantation from May 2004 to July 2007 at 3 hospitals. The primary outcomes were a composite of major adverse cardiac events (MACE) including cardiac death, myocardial infarction (MI), target-lesion revascularization (TLR), and target-vessel revascularization (TVR) after VLST occurrence.

Results: We identified 19 patients (0.53%) with angiographically documented stent thrombosis developing over 1 year after DES implantation. The mean time to VLST occurrence was 899 days (899 +/- 353). Discontinuation of antiplatelet drugs was noted in 4 (21%) patients and the average duration of discontinuation was 4 days. Clinical presentations of VLST were mainly MI (17 patients, 89%). Balloon angioplasty was only performed in 12 patients (63%) and stent implantation in 7 patients (37%). Mean follow-up duration from VLST occurrence was 620 days (620+/-256). During clinical follow-up after VLST occurrence, no cardiac deaths or MIs were detected. Target-vessel revascularization was done in 2 (11%) patients and TLR in 1 patient (6%). Major adverse cardiac events occurred in 3 (16%) patients during long-term clinical follow-up.

Conclusions: Clinical presentation of VLST after DES implantation is associated with serious adverse events, such as MI. Long-term follow-up outcomes after VLST occurrence appear unfavorable and more data from larger studies are warranted.