Coronary angiography (CAG) remains the gold standard in determining the place of percutaneous coronary intervention (PCI). Nevertheless, in multivessel lesion definition hemodynamically significant stenosis, i.e., lesions of a coronary arteries, causing myocardial ischemia, often causes difficulties. In a study of FAME (Fractional Flow Reserve versus Angiography for Multivessel Evaluation) was shown that the determination of the relative (partial), coronary flow reserve (fractional flow reserve; FFR) with stenting only hemodynamically significant stenosis by approximately 30% reduces the risk of major adverse cardiac events within one year compared with the standard strategy of PCI of all anatomically significant stenoses. In an article published in JACC for July 13, 2010, the researchers analyzed the results of 2-year surveillance study participants.
Methods and progress in the study.
The study included patients with multivessel coronary heart disease (CHD) in the presence of anatomic stenosis ≥ 50%, at least two major epicardial coronary arteries. Patients with acute myocardial infarction (MI) with a rise or without ST segment, elevation could be included within the study, but not earlier than five days from the onset of the disease. It excluded were patients with stenosis of the left coronary artery trunk was transferred coronary bypass surgery, cardiogenic shock, severe tortuosity or calcification of the coronary arteries, the life expectancy of less than two years.
The standard approach (Group CAG) PCI all anatomical stenosis (≥ 50%), was carried out according to traditional methods. At a physiological approach (group FFR) first for each stenosis by coronary catheter for pressure measurement (Radi Medical Systems, Sweden) was determined by FFR. This indicator was measured during maximal hyperemia induced by administration of adenosine (140 mcg / kg / min) through a central vein, and was calculated as the ratio of mean pressure distal to coronary stenosis for mean pressure in the aorta. Only stented lesions with FFR ≤ 0,80. All participants were implanted stents coated with antiproliferative drugs. All patients at least one year after PCI received aspirin and clopidogrel.
The primary endpoint of the study served as a combination of major adverse cardiac events (death, MI, repeat revascularization) within one year after PCI.
Secondary endpoints - death / MI, and major adverse cardiac events and their individual components up to two years of observation, duration of intervention, the number of the used contrast agent, functional class of angina at 1 and two years, the number of antianginal drugs, cost-effectiveness of treatment.
Enrollment of patients conducted from January 2006 through September 2007 in 20 centers in the U.S. and Europe. Included 1,005 patients (average age - 64 years; men - almost 75%, MI registered - 37%; transferred PCI - 27%, diabetes - 25%). Patients with acute myocardial infarction were not. CAG group (n = 496) and FFR (n = 509) was comparable in baseline characteristics, including the number of anatomic stenosis, the number of diseased arteries, the severity and extent of lesions. Mean left ventricular ejection fraction was 57%.
In a total 2,415 study participants implanted stents are coated implants - in 96, 9% cases. Under physiological approach, FFR was measured in 94% of all stenoses, and for 874 (63%) lesions it was 0.80 or less. Once these lesions were stented. In the remaining 513 (37%) cases, FFR was more than 0.80, and these stenoses did not operate.
As a result, the group of CAG stents found significantly greater than in the FFR: 2,7 ± 1,2 vs. 1,9 ± 1,3 (p <0,001). Length PCIwassimilar in both groups (70and71 minutes respectively, p = 0.51). However, in the FFR, group was used by some smaller amount of contrast medium (302 ± 127ml vs 272± 133ml, p <0,001). Lengthof hospital stay was almost the same: 3,7 ± 3,5 days after the group of CAGagainst 3,4 ± 3,3 days after the group of FFR(p= 0,05).2-yearobservation was completed in 93.6% of the participants. Overall mortality in groups of CAGand the FFR was 3.8% (19 cases)and 2.6% (13 cases), respectively (p = 0,25),the frequency of MI - 9, 9% (n = 49) and 6,1 % (n = 31) (p= 0.03).The combination of death and MIwassignificantly lower in the: 8, 4% against 12, 9% in the group of CAG(p= 0,02).The frequency of repeated revascularization was comparable to the groups: 12, 7% (n = 64) in the CAG group and 10, 6% (n = 54) in a group FFR (p= 0.30).Numberof major adverse cardiac event was not significantly lower at a physiological approach: 22, 4% in the group of CAGagainst 17.9% in the FFR (p= 0.08).The number of patients without angina, and was similar: 76% and 80% respectively (p = 0.16).
Over 2 years of observation in the FFR group recorded only one MI (0.2%) associated with non-operated stenosis, and at most 16 (3.2%) reinnervations in the not operated lesions.
Patients multivessel CHD who underwent PCI only hemodynamically important (based upon the definition of FFR) stenosis within two years remained preferable outcome than using a standard strategy of stenting of anatomically significant stenoses.
The probable cause of greater efficiency PCI-based FFR, according to the researchers, should be considered a justified use of stents in comparable ischaemic effect. PCI all angiographic stenoses, regardless of their "ischaemic potential, can lead to additional risk of stent thrombosis or restenosis, which outweighs the risk of ischemic events without stent implantation at the site of hemodynamically insignificant stenoses.
Scientists believe that the PCI based on FFR can lead to better clinical outcomes compared with conservative therapy than it was in the study COURAGE, or coronary artery bypass grafting, as shown in the study SYNTAX. This is even more likely that the fragment COURAGE study demonstrated reduced risk of death and MI in patients with stable CHD with greater freedom from myocardial ischemia.
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