Circulation. 2009;119:687-698
Aoki and colleagues recently reported in Circulation their findings on the incidence and predictors of early (within the first 30 days after implantation) stent thrombosis (ST) in 3,405 patients recruited in the Acute Catheterization and Urgent Intervention Triage Strategy (ACUITY) trial. Within 30 days, definite or probable ST occurred in 48 patients (1.4%). ST rates were not significantly different in patients treated with bare metal stents compared with drug-eluting stents (1.4% versus 1.4%; P=1.00).
By multivariable analysis using patient-level data, insulin requiring diabetes mellitus, Duke jeopardy score, preprocedural thienopyridine administration, and renal insufficiency were independent predictors of definite or probable ST. Predictors of definite ST by multivariable analysis on a lesion level included final stent minimal lumen diameter, preprocedural thienopyridine administration, extent of coronary artery disease per patient, and baseline haemoglobin level.
Importantly, several of the risk factors for ST identified in the present report may to some extent be under the control of the patient or the physician. Ensuring thienopyridine administration before the procedure in patients with ACS and emphasizing the importance of antiplatelet agent compliance after stenting (or not performing PCI in the patient likely to be noncompliant or requiring discontinuation of antiplatelet agents for planned surgery, etc) may reduce the incidence of ST within 30 days. The fact that smaller postprocedure lumen dimensions as assessed by angiography predicted ST provides important confirmatory and complementary evidence to the earlier small intravascular ultrasound studies suggesting the role of optimum technique in potentially improving patient outcomes.
Caption: The table below shows the clinical consequences of definite or definite/probable ST in the study:
Circulation. 2009;119:828-834
In a second paper appearing also in Circulation, Werkum and colleagues report on the Dutch stent thrombosis registry. All consecutive patients with an angiographically confirmed stent thrombosis presenting from January 2004 to February 2007 to 3 high-volume centres in the Netherlands were enrolled, comprising a final population of 431 consecutive patients with a definite ST. The primary end point was the composite of cardiac death and definite recurrent ST which occurred in The estimated cumulative event rates at 30 days and 1, 2, and 3 years were 18.0%, 23.6%, 25.2%, and 27.9%, respectively.
The cumulative incidence rates of definite recurrent ST, definite or probable recurrent ST, any myocardial infarction, and any target-vessel revascularization were 18.8%, 20.1%, 21.3%, and 32.0%, respectively, at the longest available follow-up. Independent predictors for the primary end point were diabetes mellitus, total stent length, severe calcification, American College of Cardiology/American Heart Association B2-C lesions, TIMI (Thrombolysis In Myocardial Infarction) flow grade < after percutaneous coronary intervention, and left ventricular ejection fraction <45%.
The implantation of an additional coronary stent during the first ST was also associated with unfavourable outcome.
Another important observation in the present study is that clinical outcome was affected by neither the type of the previously implanted stent (DES or BMS) nor the category of stent thrombosis (early versus late).
Caption: Cumulative incidence of the primary end point and its single components, cardiac death and definite recurrent stent thrombosis.
B: Cumulative incidence of secondary end points, including all-cause death (all-cause and cardiac), recurrent stent thrombosis (definite and definite or probable), and myocardial infarction.
C: Cumulative incidence of TVR related to a BMS or a DES, including or excluding the emergent PCI for recurrent stent thrombosis.
D: Cumulative incidence of the primary end point stratified according to the timing of stent thrombosis (either acute, subacute, late, or very late).
EP indicates end point; CV, cardiovascular; MI, myocardial infarction; RST, recurrent stent thrombosis; ST, stent thrombosis; and Def/Prob, definite/probable.