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[Effect of collateral circulation on the progression of left ventricular dilatation after myocardial infarct]
Insights
Coronary collateral circulation in myocardial infarction patients significantly impacts left ventricular remodeling. Patients without collaterals showed an exponential increase in end-systolic volume index, indicating adverse cardiac remodeling.
Area of Science:
- Cardiology
- Cardiovascular Research
- Interventional Cardiology
Background:
- Acute myocardial infarction (MI) can lead to significant left ventricular (LV) remodeling.
- The role of coronary collateral circulation in mitigating adverse LV changes post-MI is not fully elucidated.
- Previous studies have not extensively analyzed the long-term impact of collaterals on LV volumes and ejection fraction after MI without reperfusion.
Purpose of the Study:
- To investigate the impact of coronary collateral circulation on left ventricular remodeling in patients with acute myocardial infarction.
- To compare left ventricular volumes and ejection fraction over time in patients with and without visible collateral filling.
- To analyze the relationship between the presence of collaterals and the time elapsed since myocardial infarction.
Main Methods:
- Coronary angiography was performed on 48 patients with acute MI at varying times post-infarction (1.6 weeks to 4 years).
- Patients were categorized into two groups based on angiographic findings: presence (n=25) or absence (n=23) of collateral filling of the distal coronary artery.
- Left ventricular end-systolic volume index (ESVI), end-diastolic volume index (LVEDVI), and ejection fraction (LVEF) were assessed and compared between groups and over time intervals ( <4, 4-6, >6 weeks post-MI).
Main Results:
- Patients with coronary collaterals showed no significant time-dependent changes in LV volumes or ejection fraction.
- In contrast, patients without collaterals exhibited a significant, exponential increase in ESVI over time (y = 28.11 e^0.13x, r² = 0.99, p < 0.0005).
- No significant differences were observed in age, sex distribution, infarct localization, infarct-related vessel, or intraventricular pressures between the groups.
Conclusions:
- The presence of coronary collateral circulation is crucial in preventing adverse left ventricular remodeling after acute myocardial infarction.
- Absence of collaterals is associated with progressive and significant dilatation of the left ventricle, as evidenced by increasing end-systolic volumes.
- These findings highlight the protective role of collaterals in preserving LV function and morphology long-term post-MI.
Abstract:
48 patients (aged 50.5 +/- 8.5 years) with proven acute first myocardial infarction underwent coronary angiography 1.6 weeks to 4 years (mean 13.3 weeks) after infarction. No reperfusion interventions were performed, no patient received a longterm therapy with diuretics, glycosides, beta-blockers or ACE-inhibitors. In accordance with the angiographic results, patients were divided into two groups: 25 patients demonstrated a proximal occlusion of one major coronary artery with retrograde contrast filling by non-compromised collaterals; in 23 patients no collateral filling of the distal vessel segment was visible. The contralateral coronary arteries and corresponding LV wall segments were normal. Age, sex distribution, localization of the infarction and infarct related vessel and intraventricular pressures (LVSP = 121.2 +/- 13.5 vs. 122.1 +/- 18.9 mm Hg; LVEDP = 13.1 +/- 5.2 vs. 11.9 +/- 4.1 mm Hg) were not significantly different between both groups. Between both groups patients were compared in whom angiography was performed less than 4, 4-6, and greater than 6 weeks after infarction. In addition, occlusion of the LAD was compared with LCX- and RCA-obstructions both with and without collaterals. Patients with collaterals revealed no significant time dependent changes of the endsystolic (48.1 +/- 11.3; 56.7 +/- 20.5; 43.8 +/- 16.2 ml/m2), enddiastolic (114.9 +/- 30.6; 121.3 +/- 10.8; 99.0 +/- 22.5 ml/m2) volumes and ejection fraction (57.7 +/- 6.5; 53.9 +/- 13.5; 56.4 +/- 9.9%). In contrast in patients without collaterals ESVI increased significantly (44.2 +/- 16.2; 50.8 +/- 17.5; 68.3 +/- 30.9 ml/m2) by an exponential function (y = 28.11 e0.13x; r2 = 0.99; p less than 0.0005).(ABSTRACT TRUNCATED AT 250 WORDS)