**2. Methods**

60 Echocardiography – In Specific Diseases

predict outcome after the procedure. However, the TIMI flow and myocardial blush grades are semi-quantitative, invasive, not easily repeatable, and do not reflect subsequent events and processes at the level of the coronary artery and microcirculation. Thus, even with successful primary PCI and the high rate of patency of the culprit artery, left ventricular functional recovery is limited and not well predicted (Stone et al, 1997;

The main goal of primary PCI is to open the occluded epicardial coronary artery, and thus to re-establish blood flow to the jeopardized myocardium. In order to nourish the myocardium, blood must flow through the epicardial coronary artery segments, resistance vessels, arterioles and capillaries before reaching venules and veins. The epicardial coronary arteries are larger than 400 um, serve as conduit vessels and their diameter is regulated by shear stress and do not contribute significantly to pressure drop. Coronary resistance vessels with diameter between 100 and 400 um are affected myogenically mainly by shear stress and luminal pressure. Resistance coronary vessels with diameter less than 100um are sensitive to local tissue metabolism and directly control perfusion to the low pressure capillary bed nourishing the myocardium. Myocardial capillary density is 3500/mm2 with inter-capillary distance of 17 um , greater in the subendocardium than in the subepicardium

Microvascular injury is the leading cause for the decreased myocardial perfusion observed in about 80% of patients after successful PCI (Gibson et al, 2000; Stone et al, 1997; Zijlstra et al, 1997; Kondo et al, 1998). Various factors contribute to the limited myocardial perfusion, including micro-emboli, platelets, white blood cells, ischemic necrosis, and reperfusion injury(Chesebro et al, 1987; van't Hof, 1998; Gibson et al, 2000;

As already mentioned, myocardial blush grade as assessed in the catheterization laboratory

Extent of resolution of ST-segment elevation after primary angioplasty is an adequate

Measurement of coronary flow velocities using Doppler wire and pressure recordings to assess severity of coronary artery stenoses are invasive procedures in addition to other disadvantages (Iliceto et al 1991; Erbel et al, 1991; Kozakova et al, 1994; Donohue et al, 1993;

Trans-esophageal echocardiography visualizes only the proximal coronary arteries and Doppler sampling is feasible in less than 70% of patients (Joye et al, 1994; Kern et al 1995;

Recent technologic advances in trans-thoracic echocardiography made Doppler sampling of coronary artery velocities possible (Voci et al, 1998; Caiati et al, 1999; Hildick-Smith et al, 2000; Higashiue et al, 2001; Pizzuto et al, 2001; Takeuchi et al, 2001). Contrast agents may

indicator of the function of the microcirculation and myocardial perfusion.

**1.3 Limitations and problems of contemporary treatment** 

**1.4 Detection of dysfunction of the microcirculation** 

evaluates the function of the microcirculation.

Miller et al, 1994; Di Carli et al, 1995).

Zijlstra et al, 1997).

(Canty, 2008).

Stone et al, 2002).

Abizaid et al, 1998).

Forty five consecutive patients with acute ST elevation anterior myocardial infarction undergoing primary PCI were enrolled in the study. All fulfilled the following criteria: 1) First anterior wall ST segment elevation myocardial infarction (STEMI). 2) Primary PCI within 12 hours of the onset of symptoms. 3) Routine informed consent to perform primary PCI. Anterior STEMI was defined as continuous chest pain for at least 30 minutes and ST elevation of at least 2.0mm in ≥2 contiguous precordial ECG leads. Exclusion criteria included one of the following clinical or angiographic findings: Prior bypass surgery, previous anterior STEMI, significant left main artery disease, failed primary PCI.
