[Microcirculatory parameters in patients with myocardial infarction]

To estimate the prognostic value of the parameters of the microcirculatory bed for the assessment of risk for in-hospital death and cardiovascular events in patients with myocardial infarction (MI).

Thirty (62.5%) and 18 (37.5%) of 48 patients (mean age 63.5 +/- 10.2 years) admitted to an intensive care unit for acute coronary syndrome subsequently developed MI in the anterior and lower walls of the left ventricle (LV), respectively.

According to the GRACE scale, 28 (58.3%), 7 (14.6%), and 13 (18.1%) patients had high, low, and moderate risks for in-hospital death, respectively. Uncomplicated MI was noted in 18 (37.5%) of the patients; acute LV aneurysm was formed in 12 (25%); 14 (29.1%) had cardiac arrhythmias as frequent ventricular and supraventricular premature beats, paroxysms of ventricular fibrillation, ventricular tachycardia, atrial fibrillation and flutter. Early post-infarction angina pectoris was noted in 2 (4.2%) patients, Killip Class I and II heart failure in 36 (75%) and 12 (25%), respectively; 3 patients died (2 from myocardial rupture and 1 from ventricular fibrillation). According to GRACE scores, complicated MI was significantly more frequently encountered in patients at high risk for in-hospital death (75% versus 28.5% in those at low risk; p = 0.03). Analysis of the microcirculatory bed revealed substantial changes in microcirculation (MC), which reflected its hypereremic type and characterized high perfusion and high MC flow index. Moreover, the coefficient of variation (CV) was significantly higher than that in the control; on days 4 and 20 it did not virtually differ from that in the control on day 2.

The found changes in MC parameters (MC value and CV) may suggest the higher influence of active mechanisms for regulation of vascular tone as a response to myocardial necrosis. The role of the autonomic nervous system in the regulation of vascular tone is supported by the significant change in the normalized amplitudes of low- and high-frequency oscillations while the intravascular resistance index remained considerably higher at all follow-up stages, which may suggest that central hemodynamics is unstable in patients with MI and necessitates monitoring of their clinical status.