SERIAL MYOCARDIAL PERFUSION IMAGING WITH DIPYRIDAMOLE AND RB-82 TO ASSESS RESTENOSIS AFTER ANGIOPLASTY

The purpose of this study was to determine whether patients at high ri sk for clinical restenosis, following coronary angioplasty, could be i dentified by myocardial perfusion imaging performed with dipyridamole- Rb-82 PET. Methods: Forty-five patients (34 men, 11 women; mean age 58 .5 yr) who had successful single-vessel angioplasty and were asymptoma tic had dipyridamole-Rb-82 PET at 1 and 3 mo after the procedure. Abno rmal flow reserve in the distribution of the angioplasty artery on PET was considered to be a decrease of greater than or equal to 1 perfusi on grade in response to dipyridamole (assessed qualitatively from tomo graphic images and polar coordinate maps). Follow-up was performed for 6 mo postangioplasty. Clinical restenosis was defined as recurrent an gina similar to that occurring before angioplasty and/or greater than or equal to 50% stenosis at the angioplasty site documented angiograph ically. We analyzed abnormal flow reserve in the distribution of the a ngioplasty vessel to identify which patients were at high risk for cli nical restenosis. Results: Fourteen patients developed clinical resten osis between 1 and 6 mo postangioplasty. Abnormal relative flow reserv e in the distribution of the angioplasty vessel was present prior to t he development of symptoms in 13 of 14 patients with clinical restenos is and in 8 of 31 patients without clinical restenosis (sensitivity 93 %, specificity 74%, p < 0.0001). PET imaging successfully separated po stangioplasty patients into groups with high (62%) and low (4%) risk o f clinical restenosis. Conclusion: Abnormal relative flow reserve in t he distribution of the angioplasty vessel on dipyridamole PET identifi es asymptomatic postangioplasty patients at risk for clinical restenos is.