Assessment of coronary flow reserve by sestamibi imaging in patients with typical chest pain and normal coronary arteries.
OBJECTIVE
We assessed coronary flow reserve (CFR) by sestamibi imaging in patients with typical chest pain, positive exercise stress test and normal coronary vessels.


METHODS
Thirty-five patients with typical chest pain and normal angiogram and 12 control subjects with atypical chest pain underwent dipyridamole/rest (99m)Tc-sestamibi imaging. Myocardial blood flow (MBF) was estimated by measuring first transit counts in the pulmonary artery and myocardial counts from SPECT images. Estimated CFR was expressed as the ratio of stress to rest MBF. Rest MBF and CFR were corrected for rate-pressure product (RPP) and expressed as normalised MBF (MBF(n)) and normalised CFR (CFR(n)). Coronary vascular resistances (CVR) were calculated as the ratio between mean arterial pressure and estimated MBF.


RESULTS
At rest, estimated MBF and MBF(n) were lower in controls than in patients (0.98 +/- 0.4 vs 1.30 +/- 0.3 counts/pixel/s and 1.14 +/- 0.5 vs 1.64 +/- 0.6 counts/pixel/s, respectively, both p < 0.02). Stress MBF was not different between controls and patients (2.34 +/- 0.8 vs 2.01 +/- 0.7 counts/pixel/s, p=NS). Estimated CFR was 2.40 +/- 0.3 in controls and 1.54 +/- 0.3 in patients (p < 0.0001). After correction for the RPP, CFR(n) was still higher in controls than in patients (2.1 +/- 0.5 vs 1.29 +/- 0.5, p < 0.0001). At baseline, CVR values were lower (p < 0.01) in patients than in controls. Dipyridamole-induced changes in CVR were greater (p < 0.0001) in controls (-63%) than in patients (-35%). In the overall study population, a significant correlation between dipyridamole-induced changes in CVR and CFR was observed (r = -0.88, p < 0.0001).


CONCLUSIONS
SPECT might represent a useful non-invasive method for assessing coronary vascular function in patients with angina and a normal coronary angiogram.
Storto
Giovanni
G
Department of Biomorphological and Functional Sciences, Institute of Biostructures and Bioimages of the National Council of Research, University Federico II, Naples, Italy.
Sorrentino
Anna Rita
AR
Pellegrino
Teresa
T
Liuzzi
Raffaele
R
Petretta
Mario
M
Cuocolo
Alberto
A
D000328:Adult; D000368:Aged; D002637:Chest Pain / Q000175:diagnosis* / Q000473:pathology; D017023:Coronary Angiography / Q000379:methods; D003326:Coronary Circulation; D003331:Coronary Vessels / Q000473:pathology*; D015444:Exercise; D005080:Exercise Test; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000473:pathology; D017256:Technetium Tc 99m Sestamibi / Q000494:pharmacology; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods
D017256:Technetium Tc 99m Sestamibi