Removal of debris from the coronary arteries does not improve outcomes: Results from the A-F study

March 30, 2008 By Vijayalakshmi Kunadian MBBS MD MRCP [mailto:vkunadian@perfuse.org]

SCAI-ACCi2 08-Chicago, IL: Distal protection in high risk non-ST elevation myocardial infarction did not improve cardiovascular outcomes compared with conventional percutaneous coronary intervention (PCI) in the Angioplasty Balloon-associated Coronary Debris and the EZ Filter-wire (A-F)  trial.

Dr Mark Webster presented the results at the SCAI-i2 summit Annual Scientific Sessions in Chicago today. Anti-embolic devices such as distal protection devices, proximal protection devices and thrombus extraction devices have been studied in the setting of ST elevation myocardial infarction. The use of distal protection although proven beneficial in saphenous vein grafts has not been associated with improved cardiovascular outcomes during PCI of native coronary arteries.

The A-F trial utilized the EZ FilterWire which consists of a basket like device that is placed downstream of the coronary occlusion to trap the atherothrombotic debris. The investigators in the A-F study evaluated the benefit of the device in the setting of a non ST elevation myocardial infarction (NSTEMI).

This study was a prospective, multicenter, unblinded, two-arm, randomized trial consisting of 151 high risk patients with NSTEMI acute coronary syndromes (ACS). Percutaneous coronary intervention was performed using the Boston Scientific FilterWire (n=77) versus conventional PCI without the FilterWire (n=74). The primary endpoint of this study consisted of in-hospital major adverse cardiac events (MACE) [death, recurrent myocardial infarction (CK-MB > 3x normal), emergency coronary artery bypass surgery (CABG), repeat target vessel revascularization.

Clinical inclusion criteria included the following:
 * Elevated troponin
 * Angina at rest
 * Dynamic ST or T wave changes

Angiographic inclusion criteria included the presence of a culprit lesion with "high risk" angiographic features (2 or more of the following) which consisted of the following parameters:
 * Intra-coronary filling deficit consistent with thrombus
 * Lesion ulceration
 * Eccentric shape
 * Irregular or scalloped border
 * Abrupt edges to the lesion
 * Lesion length >20 mm

The device was successful in 97% of the cases and embolic debris was retrieved in 42% of the cases. The post-PCI TIMI 3 flow grade did not differ between the two groups (94% in both groups). There was no significant difference in the primary endpoint between the two groups (FilterWire 11.7% vs. conventional PCI 9.5%). There was also no significant difference in the secondary endpoints between the FilterWire and the conventional PCI groups in terms of MACE at 30 days (12% vs. 11%), changes in CK-MB [5.1(20) vs.4.1(6)], change in troponin T [0.4(0.7) vs. 0.4(0.6)].

The investigators concluded that the use of FilterWire among patients with NSTEMI did not result in improved outcomes in terms of a reduction in in-hospital MACE or post-procedure CK-MB or troponin elevation. The researchers suggest that “the routine use of vascular protection devices in such patients is not warranted”.

Source
Late Breaking Clinical Trials Session: SCAI Annual Scientific Sessions in partnership with ACC i2 summit, March 30, 2008 Chicago