Nitrate-enhanced gated SPECT in patients with primary angioplasty for acute myocardial infarction: evidence of a reversible and nitrate-sensitive impairment of myocardial perfusion.
OBJECTIVE
Reperfusion of myocardial infarction (MI) leads to a reversible dysfunction of coronary vessels. We hypothesised that vasodilating drugs such as nitrates might improve sestamibi uptake within viable areas of recently reperfused MI, thereby enhancing prediction of subsequent improvements in perfusion and contractility. This study was aimed at assessing nitrate-enhanced sestamibi gated SPECT after MI reperfusion.


METHODS
Twenty-nine patients underwent rest followed by nitrate sestamibi gated SPECT at 9 +/- 3 days after primary angioplasty for acute MI and at follow-up, 4-10 months later. Four MBq/kg of (99m)Tc-sestamibi was injected at rest, and 12 MBq/kg after nitroglycerin spray.


RESULTS
Follow-up improvements were documented for both perfusion (P+) and contractility (C+) in 18% of the 180 initially abnormal segments, in neither perfusion (P-) nor contractility (C-) in 44%, in contractility only (C+P-) in 16% and in perfusion only (C-P+) in 22%. Perfusion improvement was related to lower sestamibi uptake on baseline rest SPECT (P+: 42 +/- 15% vs P-: 50 +/- 15%, p = 0.001) and, moreover, to a higher increase between rest and nitrate uptake (P+: +9.5 +/- 6.5% vs P-: +2.0 +/- 5.9%, p < 0.001). Contractility improvement was related to sestamibi uptake on baseline nitrate SPECT (C+: 58 +/- 15% vs C-: 38 +/- 16%, p < 0.001), a variable enhancing the prediction provided by sestamibi uptake at rest (p < 0.05).


CONCLUSIONS
The improvement in perfusion which is documented in the months following MI reperfusion is predicted by initial nitrate enhancement of sestamibi uptake, suggesting a mechanism of reversible vascular injury. In this particular setting, sestamibi uptake is a better predictor of contractility recovery when determined after nitrate administration rather than under conventional resting conditions.
Djaballah
Wassila
W
Department of Nuclear Medicine, CHU-Nancy, Nancy, France. wassila.djaballah@wanadoo.fr
Muller
Marc A
MA
Angioï
Michael
M
Moulin
Frédéric
F
Codreanu
Andrei
A
Mandry
Damien
D
Ethevenot
Gérard
G
Karcher
Gilles
G
Aliot
Etienne
E
Marie
Pierre Y
PY
D015906:Angioplasty, Balloon, Coronary; D019317:Evidence-Based Medicine; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000150:complications / Q000000981:diagnostic imaging* / Q000628:therapy*; D009566:Nitrates; D019275:Radiopharmaceuticals; D017256:Technetium Tc 99m Sestamibi; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods*; D016896:Treatment Outcome; D014665:Vasodilator Agents; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging* / Q000209:etiology / Q000517:prevention & control*
D009566:Nitrates; D019275:Radiopharmaceuticals; D014665:Vasodilator Agents; D017256:Technetium Tc 99m Sestamibi