Purpose: Fractional flow reserve (FFR) is often performed to assess the severity of coronary artery stenoses. However, the usefulness of measuring FFR when a noninvasive test has been obtained prior to coronary angiography has not been studied.
Methods and materials: We retrospectively reviewed 122 patients who underwent noninvasive stress test with cardiac imaging (SPECT or stress echocardiography) prior to FFR assessment of a coronary lesion. The usefulness of FFR measurement was determined. FFR was judged useful if decision to revascularize the patient reflected the result of FFR rather than the result of the stress test.
Results: A total of 136 lesions were evaluated. Of these, 66 were associated with a positive noninvasive test and 70 had no ischemia present in the territory of the evaluated vessel. When FFR was negative (> or =0.75) and the test positive (57 lesions), revascularization was deferred in 55. When FFR was positive (<0.75) and the functional test negative (8 lesions), revascularization was performed in 8. FFR measurement changed the clinical decision to revascularize the patient in 55 (83%) of the 66 lesions with ischemia documented on noninvasive tests compared to 8 (11%) of the 70 lesions without ischemia (P<.0001).
Conclusion: FFR can be helpful in patients with coronary artery disease even when noninvasive testing is performed prior to coronary angiography. In this study, FFR measurement had the greatest impact in the evaluation of lesions with documented ischemia on noninvasive tests. In these patients, appropriate use of FFR based on the operator's judgment can prevent unnecessary revascularizations of intermediate lesions.