Outcomes ‘Terrible’ After Stent Thrombosis

BRUCE JANCIN
VIENNA — Urgent percutaneous coronary intervention for stent thrombosis is a situation that comes up more frequently and leads to considerably worse outcomes than generally is appreciated, Dr. Francesco Burzotta said at the annual congress of the European Society of Cardiology.
He presented the results of the Outcome of PCI for Stent Thrombosis Multicentre Study (OPTIMIST), a prospective unfunded registry of all patients who underwent PCI for stent thrombosis at 11 Rome-area hospitals during 2005 and 2006.
OPTIMIST involved 110 patients who experienced 120 stent thromboses, making this the largest-ever single series of patients with angiographically defined stent thrombosis ever reported, according to Dr. Burzotta of Catholic University of the Sacred Heart, Rome.
Stent thrombosis accounted for 3.6% of all urgent PCIs performed for ST-elevation MI at participating hospitals during the study period, so it is not a rare event. And the frequency will increase as the number of stent procedures climbs worldwide, he observed.
Clinical outcomes were disappointing, despite state-of-the-art treatment, Dr. Burzotta said. Mortality was 12% at 30 days and 16% at 6 months. The combined rate of death, myocardial infarction, stroke, or a repeat interventional procedure was 29% at 6 months.
Of the 120 stent thromboses, 62 involved drug-eluting stents (DES); the rest involved bare-metal stents (BMS). The study was not designed to assess whether the thrombosis rate was higher with DES. However, OPTIMIST did show that the clinical circumstances in which thrombosis occurs tend to be different with DES, as compared with BMS.
Stent thrombosis within 15 days after discontinuing antiplatelet therapy was nearly eightfold more frequent with DES. And thrombosis involving DES was more likely to occur late: 33 cases of stent thrombosis occurred more than 1 month post DES implantation, compared with 14 cases with BMS.
“However, once thrombosis has occurred and the patient has been directed to the cath lab, the outcome after stent thrombosis and PCI isn't significantly affected by whether it's a drug-eluting or bare-metal stent,” the cardiologist said.
Of the 110 patients, 27 underwent PCI with thrombectomy, with the choice of thrombectomy device being left to the operator. Thrombectomy was safe when performed in the high-risk setting of stent thrombosis, with no increased risk of adverse effects observed.
There was a nonsignificant trend toward higher rates of excellent TIMI-3 grade coronary blood flow in patients who underwent thrombectomy; this trend became highly significant when patients in cardiogenic shock at the time of presentation with stent thrombosis were excluded.
In a multivariate analysis, two factors were independently associated with increased 6-month mortality. Stent thrombosis occurring more than 1 year post implantation was associated with a 10-fold increased risk, while implantation of another stent during PCI for stent thrombosis conferred a 5.4-fold increased risk of mortality.
Dr. Burzotta said these findings have practical implications for interventional cardiologists: Consider keeping patients on antiplatelet therapy indefinitely after stent placement in order to reduce the risk of late thromboses, and focus on reopening the occluded artery without implanting an additional stent in an effort to prevent restenosis.
Thrombectomy during urgent PCI for stent thrombosis appears to have merit in patients without cardiogenic shock, he added.
Dr. Freek W.A. Verheugt noted in an interview that one-quarter of patients who experience stent thrombosis never make it to the catheterization laboratory because they die immediately.
“The Italian study shows that stent thrombosis—whether with a bare-metal or drug-eluting stent—is a malignant disease. One out of four patients die immediately, and the other three-quarters face an in-hospital mortality of 12%. That's terrible. We haven't seen anything like that in many years,” he said.
“That's like the in-hospital mortality in the placebo arm of the lytic trials 15 years ago,” continued Dr. Verheugt, professor and chairman of cardiology at University Medical Center, Nijmegen, the Netherlands.