Abstract 15022: Coronary Microvascular Dysfunction in Patients With Acute Coronary Syndromes in the Absence of Obstructive Coronary Atherosclerosis
Introduction: About 10% of patients admitted for a non ST-segment elevation acute coronary syndrome (NSTE-ACS) show no obstructive coronary artery disease (NO-CAD) at angiography.
Hypothesis: Abnormalities in coronary microvascular (CMV) function can be involved in NSTE-ACS with NO-CAD.
Methods: We studied 21 patients (70±8 years, 12 F) with NSTE-ACS and NO-CAD. Specific causes of NSTE-ACS presentation (e.g., epicardial spasm, takotsubo syndrome, myocarditis, transient thrombosis, etc..) were excluded by careful investigation. Before discharge, susceptibility to CMV constriction was investigated by assessing coronary blood flow velocity (CBFV) response in the left anterior descending artery to IV ergonovine (0,4 mg) by transthoracic Doppler echocardiography and expressed as the ratio between CBFV at peak ergonovine and CBFV at baseline. CMV dilator function was also assessed as the ratio between CBFV at peak IV adenosine (140 μg/kg/min) and during cold pressor test and CBFV at rest. Tests were repeated at 12-month follow-up in 8 patients.
Results: During ergonovine test, CBFV significantly decreased compared to baseline (mean -20.6%, range -3.45/-38.9%; p<0.001. CBFV responses to adenosine and to CPT were 1.23±0.2 and 1.32±0.2, significantly lower compared to those observed in a control group of 11 matched healthy controls (2.9±1.0 and 2.3±0.7, respectively; p<0.001 for both). A significant correlation was found between CBFV response to adenosine and CPT (r=0.76; p<0.001), whereas CBFV response to ergonovine was not correlated to both CBFV response to adenosine (r=-0.13; p=0.60) and CPT (r=-0.22; p=0.37). In the 8 patients who underwent follow-up assessment, CBFV response to adenosine remained unchanged (1.21±0.1 vs. 1.12±0.1, p=0.22), whereas CBFV response to CPT worsened (1.32±0.2 vs. 1.15±0.1, p=0.04). No significant changes were found in the CBFV response to ergonovine (-16.2±9.2 vs. -10.2±7.0 %, p=0.23).
Conclusions: Patients with NSTE-ACS and NO-CAD show a significant CMV dysfunction, which seems to involve both an increased vasoconstrictor activity and a reduced vasodilator function, which do not seem to be correlated and might variably contribute to the pathogenesis of the syndrome.
Author Disclosures: A. De Vita: None. G. Russo: None. P. Lamendola: None. A. Di Franco: None. A. Villano: None. L. Gentile: None. E. Ravenna: None. G. Lanza: None. F. Crea: None.
- © 2016 by American Heart Association, Inc.