HIGH PREVALENCE OF THE TL-201 REVERSE REDISTRIBUTION PHENOMENON IN PATIENTS WITH SYNDROME-X

Objective To evaluate the stress-redistribution myocardial perfusion p attern in patients with angina, positive exercise test and angiographi cally smooth coronary arteries (syndrome X). Design Prospective study. Patients and methods Twenty-five consecutive patients (seven males, m ean age 54+/-8 years) with typical angina, positive exercise test, nor mal coronary arteries and no inducible spasm, underwent stress-redistr ibution thallium-201 myocardial perfusion scintigraphy. Thirty-two con secutive patients (14 males, mean age 49+/-7 years) with atypical ches t pain and negative exercise test, undergoing stress-redistribution th allium scan, served as controls. Results Exercise was discontinued for angina and/or ST-segment depression after 12+/-3 min. Thallium stress images revealed 40 hypoperfused segments in 27 patients (77%); after 4 h, 16 of these segments had completely normalized, 10 remained uncha nged, six exhibited partial reperfusion and eight worsened. Twenty-fou r patients (69%) exhibited thallium reverse redistribution in 33 segme nts. Thirty-four patients (97%) had at least one hypoperfused segment in one of the two scintigraphic phases. Of the 24 patients with revers e redistribution, eight also underwent, stress-rest 99mTc-MIBI SPECT: six exhibited reduced tracer uptake that was present at rest, but not on stress images, in the same segments showing thallium reverse redist ribution. Thallium stress images revealed four hypoperfused segments i n three controls (9%), at redistribution, one segment normalized, two remained unchanged and one exhibited partial reperfusion. Additionally , there were four new underperfused segments appearing on redistributi on in four patients (13%). Overall, there were seven controls (22%) wi th at least one hypoperfused myocardial segment in one of the two scin tigraphic phases. Conclusions Our study confirms that perfusion abnorm alities are present in most syndrome X patients. Additionally, the dat a show that reverse redistribution (a perfusion defect that develops o r becomes more evident on delayed imaging) is a common finding in thes e patients. The mechanisms of the phenomenon remain obscure: we sugges t that it is due to inhomogeneous perfusion, and the hyperaemic respon se induced by exercise masks resting underperfusion of certain areas.