Background. Myocardial fractional flow reserve (FFR) is a useful method in assessment of functional significance of coronary stenosis. Deferral of intervention of angiographically intermediate lesion based on FFR measurement is safe in selected patient population as previously described. The aim of the study was to assess mid-term results after deferring coronary intervention of intermediate lesion in a non-selected patient population with no respect to the extent of coronary artery disease and to the results of stress tests if performed. Methods. A coronary intervention of angiographically intermediate lesion (40 - 70 % according to QCA) was deferred in a group of 50 consecutive patients (33 men, mean age 60.8 ± 10.2 y.) on the basis of FFR > 0.75 (mean FFR 0.89 ± 0.06). FFR was measured in 62 lesions (mean stenosis diameter 55 ± 7 %, left anterior descending 34 lesions, circumflex artery 13 lesions, right coronary artery 15 lesions). One-vessel disease was presented in 14 pts (28 %), 36 pts (72 %) presented with multivessel disease (two-vessel disease in 27 pts - 54 % and three-vessel disease in 9 pts - 18 %). Stress test was positive in 15 pts, in 1 pts. negative, and in 3 pts. non-diagnostic. All-cause mortality, cardiac mortality, non-fatal myocardial infarction (MI) and ischemia driven target vessel revascularization (TLR) were recorded during follow-up. Severity of angina pectoris (CCS classification) and a need for antianginal treatment (beta-blockers, nitrates, calcium channel blockers) at the baseline and at the end of clinical follow-up was recorded. Results: Follow-up was completed in 49 patients (98 %). Mean time of follow-up is 15,4 ± 2 months (range 12 - 22 months, median 15 months), two patients died (4 %) - one from colon cancer, the other patient died from lung cancer, there was not any cardiac death recorded, two patients (4 %) had target vessel revascularization. Estimated 22 months event-free (all-cause death, MI, TLR) survival was (mean ± SEM) 86 ± 7 %. There was a significant difference in symptom severity - mean grade of angina pectoris at baseline was 1.8 ± 1.3, at follow-up 1.1 ± 1.0 (p < 0,05). There was not difference in use of antianginal drugs was same at baseline and at follow-up (1.7 ± 0,8 vs. 1,7 ± 0.7). Thirty-five patients (71 %) were treated by statins. Conclusions: Deferring of coronary interventions of intermediate stenosis based on FFR measurement is safe in a mid-term follow-up. Despite of the same intensity of antianginal treatment there was a significant decrease in symptom severity.

        Key words: Myocardial fractional flow reserve - Coronary angioplasty - Coronary artery disease