The relationship between myocardial flow reserve and washout of Tc-99m sestamibi in patients with chronic heart failure

Abstract

Backgrounds: It has been well known that Tc-99m sestamibi may have the potential for freezing myocardial perfusion. However, this agent does not freeze myocardial perfusion in a certain situation such as impaired myocardium (JNM 1996:1289–94). The abnormalities of Myocardial blood flow (MBF) and flow reserve have been observed in patients with chronic heart failure (CHF) and MBF reserve may play an important role of the prognosis in these patients. This study was designed to compare myocardial blood flow and flow reserve with washout of Tc-99m sestamibi in CHF patients. Methods: MBF and MBF reserve were measured in 10 patients with CHF due to non-ischemic cardiomyopathy and 10 control subjects by means of O-15 Water PET. Myocardial planar images were also performed using Tc-99m sestamibi in order to measure washout (WO). These parameters were compared to other CHF parameters such as ejection fraction and BNP. Results: The values of MBF reserve in CHF patients significantly decreased compared to control (1.93 + 0.39 versus 3.00 + 0.79, p<0.05), though MBF at rest did not significantly change. The WO in these patients significantly increased compared with control (34.0 + 6.3% versus 26.5 + 4.0 %, p<0.05). And in addition, the values of WO showed a significant negative correlation to MBF reserve in patients with CHF (r=-0.81). The values of WO were not correlated with ejection fraction, but with BNP (r= 0.76). Conclusions: These results indicated that both myocardial flow reserve and washout of Tc-99m sestamibi were impaired in patients with CHF, reflecting the existence of myocardial cell damage. And in addition, the washout of Tc-99m sestabmibi were closely correlated with myocardial flow reserve and BNP, suggesting the washout of Tc-99m sestamibi might be useful for the risk stratification in patients with CHF.