In patients with acute myocardial infarctions (MIs), cholesterol levels are no longer
valid after 24 h from presentation because acute MI causes a rapid decline in serum
levels of total cholesterol, low-density lipoprotein (LDL) cholesterol, and high-density
lipoprotein (HDL) cholesterol. The objective of this study was to evaluate the effect
of acute MI on the total cholesterol/HDL cholesterol ratio and the LDL cholesterol/HDL
cholesterol ratio.
The study consisted of 45 patients who were admitted to the hospital with acute MIs.
Serum levels of total cholesterol, HDL cholesterol, LDL cholesterol, and triglycerides
were determined on day 1 post-MI and day 4 post-MI. The total cholesterol/HDL cholesterol
ratio and the LDL cholesterol/HDL cholesterol ratio were calculated. Serum lipid levels
and cholesterol ratios were compared between day 1 post-MI and day 4 post-MI.
From day 1 post-MI to day 4 post-MI, the mean (+/- SD) serum levels of total cholesterol
(188.4 +/- 52.5 vs. 170.5 +/- 57.2 mg/dL, respectively; p = 0.01), LDL cholesterol
(120.3 +/- 48.9 vs. 105.9 +/- 43.0 mg/dL, respectively; p = 0.009), and HDL cholesterol
(45.0 +/- 18.5 vs 39.3 +/- 16.1 mg/dL, respectively; p < 0.001) decreased, but the
mean serum level of triglycerides (119.2 +/- 81.2 vs 149.3 +/- 68.3 mg/dL, respectively;
p = 0.006) increased. The cholesterol ratios, however, remained unchanged between
day 1 post-MI and day 4 post-MI. The total cholesterol/HDL cholesterol ratio was 4.59
+/- 1.84 on day 1 post-MI and 4.67 +/- 1.77 on day 4 post-MI (change not significant).
The LDL cholesterol/HDL cholesterol ratio was 2.96 +/- 1.58 on day 1 post-MI and 2.99
+/- 1.44 on day 4 post-MI (change not significant).
Acute MI does not affect the cholesterol ratios. Therefore, when the absolute levels
of serum cholesterol are no longer valid (beyond 24 h after an MI), the cholesterol
ratios still could be useful for cholesterol risk assessment in patients with acute
MIs.