IMR Assessment in Patients With New Diagnosis of Left Ventricle Dilatation

Index of Microcirculatory Resistance (IMR) Assessment in Patients With New Diagnosis of Left Ventricular Dilatation Without Significant Coronary Artery Lesions: IMPAIRED Pilot Trial

To establish if, in patients with new diagnosis of left ventricular dilatation without documentation at the coronary artery angiography of significant coronary artery lesions, there is a damage of the coronary microcirculation at the IMR (index of microcirculatory resistance) assessment

The Authors will enroll at the moment of coronary artery angiography patients without history of ischemic heart disease and new diagnosis (at transthoracic echocardiography) of left ventricular dilation.

All patients will undergo coronary artery angiography. To be enrolled, it is necessary to have the absence of significant coronary artery stenosis (angiographic evaluation of the lesion >40%) in all the vessels (main and side branch).

The Authors will proceed to perform the evaluation of the index of microvascular resistance (IMR). The target vessel will be the left anterior descending artery.

An intracoronary pressure/temperature sensor-tipped guidewire will be used. Thermodilution curves will be obtained during maximal hyperemia. The IMR will be calculated from the ratio of the mean distal coronary pressure at maximal hyperemia to the inverse of mean hyperemic transit time.

Inclusion Criteria:

• new diagnosis of left ventricular dilation (dilatative cardiopathy)
• absence of significant (>40%) coronary artery disease at coronary artery angiography

Exclusion Criteria:

• history of ischemic heart disease
• history of significant valvular disease
• contraindication to hyperemic agent