The STENT Registry methods consist of a centralized database, data entry by each center locally into a secure web-based database, Executive Steering Committee of physicians and hospital administrators overseeing all data collection, quality assessment, periodic reports, data analysis and publication, and a working group of data coordinators from each center with regular scheduled conference calls and scheduled meetings to homogenize policies and procedures. Full patient consent is required for patient participation due to prospective design of the registry and the database is designed in full adherence with health insurance portability and accountability act (HIPAA) guidelines. Patient contact by phone for clinical outcomes is obtained 9 months following the procedure, with clinical outcomes consisting of the major adverse cardiac events (MACE) endpoints (i.e., death, MI, target vessel revascularization [TVR], stent thrombosis, stroke or peripheral vascular event). Physician adjudication is performed of MACE events and routine audits of data report forms against source documents is performed in 10% of the first 4000 patients in the registry and 5% thereafter.
During the study period of May 2003 through December 2005, a total of 9707 patients (93% of all eligible) completed 9-month follow-up for MACE endpoints. Table 1 shows the breakdown of thrombus grade 3 or higher procedures (n = 1515 with 9-month follow-up) (15.6% of all procedures with 9-month follow-up). Of these procedures, no thrombectomy or distal protection was performed in 1168 (12.0%) and AngioJet without distal protection was performed in 200 (2.0%). These two groups of patients represent the patient population compared for clinical outcomes to assess any differences between the AngioJet and “no thrombectomy” patient groups for TIMI thrombus grade 3 or higher procedures.
There were no significant differences in demographics or cardiac history between the AngioJet (n = 200) and the “no thrombectomy” (n = 1168) groups. However, on clinical presentation, more three-vessel disease was present in the “no thrombectomy” group, but significantly higher percentages of cardiogenic shock was present in the AngioJet group (8% vs. 4%, p = 0.02). In addition, patients presenting in the AngioJet group had more hypotension, abrupt closure and acute evolving MI at presentation, and also a higher percentage of patients with in-stent thrombosis (12% vs. 5%, p = 0.0003). Pre-TIMI procedural flow showed a lower rate of TIMI grade 3 flow with the AngioJet vs. “no thrombectomy” group (15% vs. 27%, p = 0.0001). This resulted in slightly lower post-procedure TIMI grade 3 flow for the AngioJet group (85% vs. 93%, p = 0.0003). Thrombus grade 4 and 5 were also more common for the AngioJet group (76% vs. 62%, p = 0.0005). Lesion lengths were no different between the two groups; however, vessel diameter was significantly larger for the AngioJet group, averaging 3.3 mm vs. 3.0 mm for the “no thrombectomy” group.
The unadjusted 9-month clinical outcomes comparing the AngioJet and “no thrombectomy” groups are shown in Table 2. This shows a mortality rate of 5.0% for AngioJet and 6.5% for “no thrombectomy” groups (p = 0.528). Overall post-procedure MI and TVR rates were slightly higher for the AngioJet group, although not statistically, which lead to a trend toward a slightly higher overall MACE rate for AngioJet 14.0% vs. “no thrombectomy” group 11.6%, p = 0.346). The differences in the outcomes were not statistically significantly different for the two treatment strategies. This is of interest, given the higher percentage of high-risk patients in the AngioJet group. If the cardiogenic shock patients are omitted, the unadjusted clinical outcomes at 9 months are shown in Table 3. This shows continued numerically lower mortality rate for the AngioJet group vs the “no thrombectomy” group (2.8% vs. 4.4%, p = 0.421).
Thrombus grade greater than 3 is present frequently in real-world practice in this large, multicenter registry (15.4% of all procedures). The use of thrombectomy devices as a percentage of all cases and for cases containing thrombus grade 3 or greater in acute STEMI cases is low (3–5% overall, 10–15% of thrombus cases and 8–12% of STEMI cases. When examined for AngioJet alone vs. “no thrombectomy,” procedures with thrombus grade 3 or higher, 9-month mortalities were numerically lower for AngioJet procedures (not significantly different), but overall MACE is not significantly different. As the number of procedures with other thrombectomy devices increases, future analyses will compare clinical outcomes with these devices compared to AngioJet rheolytic thrombectomy.
- Ali A, Cox D, Dib N, et al. Rheolytic thrombectomy with percutaneous coronary intervention for infarct size reduction in acute myocardial infarction: 30 day results from a multicenter randomized study. J Am Coll Cardiol 2006 (In Press).