Relationships between myocardial perfusion abnormalities and poststress left ventricular functional impairment on...

To evaluate the interplay between myocardial ischaemic burden and poststress left ventricular (LV) systolic and diastolic abnormalities in patients with suspected or known coronary artery disease (CAD).

A total of 471 patients underwent myocardial perfusion imaging by cadmium-zinc-telluride scintigraphy and coronary angiography. A fast imaging protocol was used with stress imaging performed 10 - 15 min after tracer injection. The summed difference score (SDS) and the percent stress-to-rest ratios for LV ejection fraction and peak filling rate (PFR), measures of stress-induced systolic and diastolic impairment, were computed from scintigraphic images. A SDS of >3 was considered abnormal and >7 a marker of moderate-to-severe ischaemia.

Of the 471 patients, 321 (68%) showed significant CAD in one (27%), two (23%) or three (18%) vessels. The extent of CAD associated with gradual alterations in SDS (P < 0.001). Interestingly, while impairment in the percent stress-to-rest PFR ratio paralleled the increase in the extent of CAD (P < 0.001 for trend), the occurrence of significant stress-induced systolic dysfunction was limited to patients with multivessel disease (P < 0.001 vs. patients without CAD, and P = 0.002 vs. patients with single-vessel disease). Similarly, while a strict correlation between percent stress-to-rest PFR ratio and myocardial ischaemic burden was evident (P < 0.001), significant stress-induced LV systolic impairment was limited to patients with moderate-to-severe ischaemia (P < 0.001 vs. patients with no or mild ischaemia).

Stress-induced LV diastolic impairment is associated with a less extensive ischaemic burden and CAD extent than poststress systolic dysfunction, which is limited to patients with multivessel CAD.