FilterWire-Ex as an Adjunct to Primary PCI - FilterWire-Ex as an Adjunct to Primary PCI
The goal of the trial was to determine the safety, feasibility, and impact on myocardial reperfusion of the FilterWire-Ex (FW), a distal embolic protection device, as an adjunct to primary percutaneous coronary intervention (PCI) in patients with acute myocardial infarction (MI).
The distal embolic protection device FilterWire-Ex (FW) can safely and feasibly be used as an adjunct to primary PCI in patients with acute MI.
Patients Enrolled: 106
Mean Follow Up: 30 days
Mean Patient Age: mean age 60-61 years
Mean Ejection Fraction: Mean LVEF 43% in FW patients and 45% in controls (p=0.201)
Presentation within six hours from symptom onset; chest pain lasting >30 minutes and resistant to intravenous nitrates; ≥0.2-mV ST-segment elevation in at least two contiguous leads on 12-lead ECG; and infarct-related native artery with a reference lumen diameter >3.0 mm and with TIMI flow grade <3
Significant left main coronary disease, cardiogenic shock at admission, or thrombolytic therapy
Feasibility and safety of adjunctive use of the FW during primary PCI
Markers of effective reperfusion (ST resolution, myocardial blush grade, and cTFC); peak CK and CK-MB release, change in LVEF and wall motion score index at 30 days compared with admission; and incidence of MACE, including death, reinfarction, and need for target vessel revascularization at 30 days
Consecutive patients undergoing primary PCI were treated with an FW distal embolic protection device (n=53). For each FW patient, a matched control was chosen, matching on: 1) infarct-related artery; 2) pre-PCI thrombolysis in MI (TIMI) flow grade; 3) gender; and 4) age ±4 years. The matching was performed blinded to procedural and clinical outcomes.
Unfractionated heparin (7500 IU), aspirin (500 mg), and beta-blockers if not contraindicated. Use of glycoprotein IIb/IIIa inhibitors was at the discretion of the physician. Activated clotting time was maintained between 250-300 seconds during the procedure. Aspirin and clopidogrel at standard dosages were administered poststent.
The FW was successfully positioned in 47/53 patients (89%) without complication. Coronary flow was temporarily reduced during FW deployment in 14 cases (30%), but TIMI grade 3 flow was restored after FW retrieval in all cases. All of the filters that underwent histological analysis (n=13) contained multiple embolic debris. Postprocedure corrected TIMI frame counts (cTFCs) were lower in FW patients compared with controls (22 ± 14 vs. 31 ± 19, p=0.005).
Additionally, grade 3 myocardial blush was more frequent in FW patients than controls (66% vs. 36%, p=0.006) as was early ST-segment elevation resolution (80% vs. 54%, p=0.006). FW use remained the only independent predictor of early ST-segment elevation resolution (odds ratio [OR] 0.18, 95% confidence interval [CI] 0.06-0.56, p=0.003) and of myocardial blush grade 3 (OR 0.33, 95% CI 0.13-0.81, p=0.01) in the multivariate model. Peak creatine kinase-MB was lower in FW patients (236 ± 172 vs. 333 ± 219 ng/ml, p=0.013).
Additionally, FW patients had greater improvement in ejection fraction (EF) at 30 days (+7 ± 4% vs. +4 ± 7%, p=0.012) and left ventricular wall motion score index (-0.30 ± 0.19 vs. -0.18 ± 0.26, p=0.008). There was no difference in 30-day major adverse cardiac event (MACE) rates (5% for FW vs. 11% for controls, p=0.488).
Among patients with acute MI undergoing primary PCI, adjunct use of the FW distal embolic protection device was safe and feasible, and was associated with lower TIMI frame counts and improved myocardial blush grade. Distal embolization during primary PCI has been shown to reduce reperfusion and increase the risk of death.
While the present study showed a definite improvement in epicardial and myocardial perfusion, the study was underpowered to determine an effect on clinical outcomes. Further randomized trials are warranted, given the promising results of this case-control study. However, the total sample size of the study was small, and it was not a randomized trial; as such, limited conclusions can be drawn. Additionally, the endpoints of the study were not evaluated by an independent, validated core laboratory.
Limbruno U, Micheli A, De Carlo M, et al. Mechanical prevention of distal embolization during primary angioplasty. Safety, feasibility, and impact on myocardial perfusion. Circulation. 2003;108:171-6.
Clinical Topics: Invasive Cardiovascular Angiography and Intervention
Keywords: Odds Ratio, Myocardial Infarction, Creatine Kinase, MB Form, Electrocardiography, Percutaneous Coronary Intervention, Stents, Heart Diseases, Embolic Protection Devices, Case-Control Studies, Chest Pain, Nitrates, Confidence Intervals, Myocardial Reperfusion
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