Absent or moderately reduced microvascular reflow on scintigraphy was associated with a longer time to recanalization compared to normal or slightly reduced reflow (290.4 vs 177.3 min; p=0.0238).
Observational (n=25)
Does the severity of microvascular no-reflow assessed by technetium-99m MAA scintigraphy correlate with ischemia time and myocardial damage in patients with acute myocardial infarction?
Scintigraphic no-reflow phenomenon occurs in a subgroup of AMI patients without angiographic no-reflow, and its severity correlates with prolonged ischemia time and worse myocardial damage.
Absolute Event Rate: 290.4% vs 177.3%
p-value: p=0.0238
OBJECTIVES: The aim of this study was the scintigraphic evaluation of clinical no-reflow phenomenon. BACKGROUND: In patients with acute myocardial infarction, the relationship of the severity of reduction of microvascular reflow to the ischemia time or to the secondary extension of myocardial necrosis is poorly understood, and we accordingly conducted a scintigraphic evaluation of clinical no-reflow phenomenon. METHODS: The group studied consisted of 25 consecutive patients with their first acute myocardial infarction. After recanalization, each patient received intracoronary injections of technetium-99m macroaggregated albumin (MAA). RESULTS: Eight patients (32%) had absent tracer uptake (scintigraphic no-reflow phenomenon). Fourteen patients showed absent or moderately reduced MAA uptake (group 1) and 11 showed slightly reduced or normal uptake (group 2). The time to recanalization was significantly longer in group 1 than in group 2 (290.4+/-130.6 min vs. 1773+/-93.5 min; p=0.0238). In chronic phase, the thallium-201 (TI-201) defect score index was significantly larger (p < 0.01) and regional ejection fraction was significantly lower (p < 0.01) in group 1 compared with corresponding values in group 2. No significant deterioration from acute phase to chronic phase in either TI-201 defect score index or regional ejection fraction was found in either group (two-way repeated measures analysis of variance). CONCLUSIONS: These findings suggest that scintigraphic noreflow phenomenon occurs in a subgroup of patients without angiographic no-reflow phenomenon, that the myocardial damage depends on the severity of microvascular damage and that prolonged ischemia time may increase the likelihood of "microvascular no-reflow phenomenon."
Kondo et al. (Thu,) conducted a observational in Acute myocardial infarction (n=25). Technetium-99m macroaggregated albumin scintigraphy was evaluated on Time to recanalization (p=0.0238). Absent or moderately reduced microvascular reflow on scintigraphy was associated with a longer time to recanalization compared to normal or slightly reduced reflow (290.4 vs 177.3 min; p=0.0238).