Clinical and Angiographic Predictors of Microvascular Dysfunction in ST-Segment Elevation Myocardial Infarction

Abstract

PurposeWe aimed to discover clinical and angiographic predictors of microvascular dysfunction using the index of microcirculatory resistance (IMR) in patients with ST-segment elevation myocardial infarction (STEMI).Materials and MethodsWe enrolled 113 patients with STEMI (age, 56±11 years; 95 men) who underwent primary percutaneous coronary intervention (PCI). The IMR was measured with a pressure sensor/thermistor-tipped guidewire after primary PCI. The patients were divided into three groups based on IMR values: Low IMR [<18 U (12.9±2.6 U), n=38], Mid IMR [18-31 U (23.9±4.0 U), n=38], and High IMR [>31 U (48.1±17.1 U), n=37].ResultsThe age of the Low IMR group was significantly lower than that of the Mid and High IMR groups. The door-to-balloon time was <90 minutes in all patients, and it was not significantly different between groups. Meanwhile, the symptom-onset-to-balloon time was significantly longer in the High IMR group, compared to the Mid and Low IMR groups (p<0.001). In the high IMR group, the culprit lesion was found in a proximal location significantly more often than in a non-proximal location (p=0.008). In multivariate regression analysis, age and symptom-onset-to-balloon time were independent determinants of a high IMR (p=0.013 and p=0.003, respectively).ConclusionOur data suggest that age and symptom-onset-to-balloon time might be the major predictors of microvascular dysfunction in STEMI patients with a door-to-balloon time of <90 minutes.

Mechanical and Pharmacological Revascularization Strategies for Prevention of Microvascular Dysfunction in ST-Segment Elevation Myocardial Infarction: Analysis from Index of Microcirculatory Resistance Registry Data

“…Previous studies have reported that the occurrence of heart failure (higher Killip class), multivessel disease, and a longer duration from symptom onset was associated with poor prognosis [15,25]. Also, the IMR value well correlates with peak troponin-I concentration [24].…”

“…e index of microcirculatory resistance (IMR) can provide a quantitative assessment of the microvascular function of epicardial stenosis and hemodynamic condition independently. IMR is considered an independent, powerful predictor of microvascular damage in STEMI [11][12][13][14][15]. Recent studies demonstrated that IMR assessed immediately after primary PCI is well correlated with the recovery of left ventricular function in STEMI [1,7].…”

Invasive Assessment of the Coronary Microcirculation in Reperfused ST-Segment–Elevation Myocardial Infarction Patients

“…High IMR values at the time of PPCI have been associated with larger MI size by cardiac enzymes 45 , less wall motion recovery at follow-up by echocardiography 45,46 , less viability by 18F-fluorodeoxyglucose positron emission tomography (FDG PET). 46 Factors predisposing to high IMR values have not been well studied but in a small study of 113 STEMI patients, Baek et al 47 found age and symptom-to-balloon time to be major predictors of high IMR.…”

Therapeutic Hypothermia for Cardioprotection in Acute Myocardial Infarction

“… 21 43 44 45 Microvascular resistance is one of important predictors of clinical outcomes in patients with AMI. 46 47 48 To attenuate reperfusion injury and microvascular alteration, maintenance of TH after revascularization is an another important issue needed to be addressed. 15 16 38 …”