Safety of deferring angioplasty in patients with normal coronary flow velocity reserve

Background. In the catheter laboratory there is a need for functional tests validating the hemodynamic significance of coronary artery stenosis. Objectives. It was the objective of our study to compare the long term card iac event rate and the clinical symptoms in patients with reduced coronary flow velocity reserve (CFVR) and standard PTCA with patients with normal CF VR and deferred angioplasty. Methods. Our study included 70 patients,vith intermediate coronary artery s tenoses (13 f, 57 m; diameter stenosis >50%, <90%) and an indication for PT CA due to stable angina pectoris and/or signs of ischemia in noninvasive st ress tests. CFVR was measured distal to the lesion after intracoronary admi nistration of adenosine using 0.014 inch Doppler-tipped guide wires. Results. In 22 patients (31%), PTCA was deferred due to a CFVR greater than or equal to 2.0 (non-PTCA group). In the remaining 48 patients (69%) mean CFVR of 1.4 +/- 0.23 (p < 0.001) was measured (PTCA group). CFVR increased to 2.0 +/- 0.51 after angioplasty. During follow-up (average 15 +/- 6.0 mon ths), the following major adverse cardiac events (MACE) occurred: in the PT CA group re-PTCA was performed in nine patients (18.8%) because of unstable angina, five patients (10.4%) suffered an acute myocardial infarction (MI) (two infarctions occurred during the angioplasty, three patients suffered an infarction during follow-up), two patients (4.2%) needed blood transfusi ons due to severe bleedings, two patients (4.2%) underwent bypass surgery a nd one patient (2.1%) died. In the non PTCA group, angioplasty was necessar y only in two cases (9.1%) during follow-up. We did not observe any MI in t he non-PTCA group. The overall rate of MACE was significantly lower in the non-PTCA group comp ared to the PTCA group (9.1% vs. 33.3%, p < 0.01). However, only 40% of the patients of the non-PTCA group were free of angina pectoris at stress, In the PTCA group, 63% did not complain of any symptoms at follow up (p < 0.05 ), Conclusions. We conclude that determination of the CFVR is a valuable param eter for stratifying the hemodynamic significance of coronary artery stenos is. PTCA can safely be deferred in patients with significant coronary steno sis but a CFVR greater than or equal to 2.0. The total rate of MACE at foll ow up was below 10% among these patients. However, if PTCA was deferred the number of patients who are free of angina is lower compared to those patie nts who underwent angioplasty, (C) 1998 by the American College of Cardiolo gy.