What is Hypercholesterolemia?

Hypercholesterolemia is a metabolic disorder which causes elevated LDL cholesterol levels. Familial Hypercholesterolemia (FH) is genetically determined and leads to LDL receptor mutation or to a mutation in the apolipoprotein B of LDL. Additionally to the LDL molecules, Lipoprotein a (Lp(a)) which consists of an LDL-particle and apolipoprotein (a) represents also an independent risk factor for atherosclerosis.
Heterozygous patients of FH have untreated LDL cholesterol levels of 200-500mg/dL, while homozygous patients can even reach levels up to 1000mg/dL and experience their first cardiac event before the age 20 if the LDL cholesterol level remains untreated. Lp(a) is recognized as risk factor for atherosclerosis when reaching levels above 30mg/dL.

What are the target levels for LDL cholesterol?
The German Guidelines established target levels are defined for patients with very high risk profile if:

No CHD (Coronary Heard Disease) with one risk factor
<160 mg/dL
With CHD with one risk factor
<130 mg/dL
With CHD/atherosclerosis
<100 mg/dL
With CHD/atherosclerosis and diabetes mellitus type 2
<70 mg/dL


Calculate LDL-cholesterol level
Friedewald formula

LDL cholesterol [mg/dl] = Total cholesterol [mg/dl] – HDL cholesterol [mg/dl] – Triglycerides/5 mg/dl]


This standardized formula is estimating the LDL cholesterol plasma level by using the levels of total cholesterol, HDL cholesterol and triglycerides without the need of using any ultracentrifuge. The formula has been established in diagnosis and therapy control of medical practice.

CAVE: Friedewald Formula is not applicable if...

  • ...Plasma triglyceride concentration is  > 400 mg/dl (triglycerides/5 level does not correspond
    anymore to the VLDL-cholesterol in this case)
  • ...Chylomicronemia present (VLDL cholesterol level is overestimated in this case)

 

When should apheresis be the treatment of choice?
Apheresis is the treatment of choice for patients with:

  1. Homozygous Familial Hypercholesterolemia
  2. Severe Hypercholesterolemia, that is insufficiently treated with drugs over a 12 month period due to intolerance and/or incompatibility of the medication. Progressive cardiovascular disease has to be proven not to be stopped by the established treatment methods (change of life style and diet, combination of drug therapy such as statins and ezetimibe and others).

How frequently has the treatment to be carried out to reach the target level?
It depends on the severity of the lipid-disorder and the treatment target level depending on the risk profile. In most cases a weekly or biweekly treatment frequency is sufficient. One treatment session takes about 1.5 - 3 hours and is performed as outpatient care.


Calculate the total body blood volume (TBV)
Nadler-Allen-Formula

Females
TBV [ml] = 183 + (356 x Height³ [meters]) + (33.1 x Weight [kg])
Males
TBV [ml] = 604 + (367 x Height³ [meters]) + (32.2 x Weight [kg])

 

Unit conversion [mg/dl] and [mmol/l]
Measured lipoproteins in the blood are mainly determined in "milligram per deciliter" [mg/dl] or in "millimole per liter" [mmol/l].
One can convert both units using the following formular.
The conversion factor is valid for total cholesterol, LDL cholesterol and HDL cholesterol.

Converter [mg/dl] and [mmol/l]

[mmol/l] → [mg/dl]
[mg/dl] → [mmol/l]
Cholesterol: [mmol/l] * 38,67 = [mg/dl]
Cholesterol: [mg/dl] * 0,02586 = [mmol/l]
Triglyceride: [mmol/l] * 87,5 = [mg/dl]
Triglyceride: [mg/dl] * 0,01143 = [mmol/l]