Assessment of Coronary Microvascular Dysfunction After STEMI Using Continuous Saline Thermodilution

Continuous saline thermodilution for determination of microvascular resistance reserve (MRR) is a novel operator-independent method to assess coronary microvascular function. CST has been studied in the setting of angina with nonobstructive coronary arteries (ANOCA), but not in the setting of acute MI. In contrast, bolus thermodilution, used to determine the index of microcirculatory resistance (IMR), has been shown in the setting of STEMI to predict extent of myocardial injury and long-term clinical outcomes (e.g., heart failure, mortality, nonfatal MI, and ischemic stroke). In contrast to bolus thermodilution techniques, CST does not require the use of active medications (e.g., papaverine or adenosine) -- only a small volume of normal saline.