Authors
- Boško Skorić — University of Zagreb School of Medicine, Zagreb, Croatia — ORCID: 0000-0001-5979-2346
Abstract
The most recent Guidelines for the management of dyslipidemias of the European Society of Cardiology and the European Atherosclerosis Society arrived after two major studies that demonstrated the efficiency of proprotein convertase subtilisin/kexin type 9 inhibitors (PCSK9i), as well as the key fact that every additional reduction of LDL cholesterol reduces increased cardiovascular risk, i.e. that there is no lower limit of target blood concentration of LDL cholesterol. The latter was reflected in the recommendation of significantly lower target values of LDL cholesterol, especially for people with high and very high cardiovascular risk, resulting in the recognition of the need to combine statins with other hypolipemic agents, primarily ezetimibe followed by PCSK9i. Omega-3 fatty acids are recommended for the treatment of high-risk patients with hypertriglyceridemia despite statin treatment. Some modifications were made to cardiovascular risk categories, primarily for patients with diabetes mellitus and familial hypercholesterolemia, and more importance has been assigned to determining apolipoprotein B and lipoprotein(a) for more precise assessment of cardiovascular risk. We are now tasked with investing significant efforts into implementing these recommendations in our daily clinical practice in order to further reduce the population burden of cardiovascular diseases.
Keywords
dyslipidemias, guidelines, management, cardiovascular risk
DOI
https://doi.org/10.15836/ccar2021.87Full Text
## Lipids and lipoproteins The guidelines emphasize the atherogenic properties of lipoprotein particles containing apolipoprotein B (ApoB), i.e. LDL, VLDL, and residual particles. ( 7 ) Routine measurement of TC and HDL-C, required to calculate the risk using the SCORE system, is still recommended, as well as LDL-C measurement, which is the primary lipid target for screening, diagnosis, and treatment, and finally triglyceride measurement. The new guidelines attribute more importance to measuring non-HDL-C and ApoB in order to evaluate the risk in people with high triglycerides, diabetes mellitus, obesity, and very low values of LDL-C. A novelty is that ESC now recommends measuring Lp(a): 1) in adults, at least once in their lifetime; 2) in persons with family history of premature CVD (men <55 years, women <60 years); 3) in persons bordering between moderate and high CV risk. The American National Lipid Association has additionally recommended to measure Lp(a) in persons with premature ASCVD, persons with familial hypercholesterolemia, very high LDL-C (≥4.9 mmol/L), borderline indication for prescribing hypolipemic agents, progressive ASCVD despite receiving hypolipemic agents, and in case of an unexpectedly poor response of LDL-C to drugs. ( 8 ) Lp(a) is a type of LDL particle whose apolipoprotein B molecule is connected with an apolipoprotein(a) molecule. Lp(a) easily penetrates the endothelium and stays in the arterial wall, causing atherosclerosis. The detrimental effect of this particle is further increased by its pro-coagulant and pro-inflammatory properties. Lp(a) >430 nmol/L is considered to increase the risk of ASCVD to a level equal to that in people with heterozygous familial hypercholesterolaemia. ( 9 ) There are no clear recommendations on treating persons with elevated Lp(a), but PCSK9i is recommended in addition to intense statin and ezetimibe therapy, and certain patients can be treated with apheresis. ( 1 , 8 ) Taking into consideration the strong evidence for the continued reduction of CVR proportionate to the reduction of serum levels of LDL-C, the ESC Guidelines suggest therapeutic strategies based on the level of risk and LDL-C concentration in each individual. However, it is advised to avoid overtreatment in elderly persons based on their high SCORE risk just because of their high age, when their other risk factors are relatively low. Treatment goals, lifestyle modifications, and drugs for treatment of dyslipidemias The basic approach for the prevention and treatment of CVD involves lifestyle modifications, arterial pressure control, and reduction of LDL-C due to its key role in the development of atherosclerosis. With the exception of persons with low CVR, target values of LDL-C have been significantly reduced in all other risk categories ( Table 1 ). Unlike the 2016 Guidelines, the new guidelines differentiate between the recommended LDL-C values in persons with low and moderate risk. Non-HDL-C and ApoB are recommended as secondary therapeutic goals for the lipid profiles of people with moderate to very high risk: non-HDL-C <2.2 mmol/L and ApoB <65 g/L for persons with very high risk; non-HDL-C <2.6 mmol/L and ApoB <80 mg/dL for persons with high risk; non-HDL-C <3.4 mmol/L and ApoB <100 mg/dL for persons with moderate risk. Even the introduction to the 2019 Guidelines already emphasizes the clinical importance of lowering LDL-C according to the principle “the lower, the better”, i.e. without a defined lower limit of LDL-C value, and the non-existence of evidence of any complications caused by LDL-C being “too low”. With each reduction in LDL-C by 1 mmol/L, we reduce the relative risk of cardiovascular complications by approximately 20%. ( 10 ) These high-set therapeutic goals require more intense therapeutic measures, and thereby also a frequent need to combine hypolipemic agents. Because of the above, the guidelines suggest algorithms and tables with practical recommendations depending on the patient’s risk category, baseline LDL-C level, and its expected reduction with certain types of hypolipemic drugs. The effect of treatment with hypolipemic drugs should be evaluated after 1-3 months or in the same interval after treatment intensification, until the therapeutic goal is reached. Great importance is attributed to lifestyle modifications, Mediterranean diet, especially using extra virgin olive oil, daily physical activity for ≥30 min, reduced intake of saturated fats and food and beverages with added sugar, and completely avoiding trans fats in one’s diet, although the latter measure lowers TC and LDL-C and increases HDL-C by a mere 5-10%. The expected effect of weight loss on the reduction of serum triglycerides in obese persons has been reduced. The basic medicinal products for the treatment of dyslipidemias are statins, cholesterol absorption inhibitors, proprotein convertase subtilisin/kexin type 9 inhibitors (PCSK9i), and fibrates. The guidelines advise a cascade therapeutic strategy starting with a high-intensity statin. If target LDL-C is not achieved, we enhance it by adding ezetimibe and finally a PCSK9 inhibitor. ## Statins Statins have the capacity to lower LDL-C by up to 50%. A reduction of LDL-C concentration by 1 mmol/L with statin therapy reduces the risk of major adverse CV events by 22%, coronary incidents by 23%, and the total 5-year mortality by 10%. Statins are effective even in people older than 75. Statins have not demonstrated benefits in patients on hemodialysis or patients with heart failure. Although they show class effect, the choice of statins depends on the desired therapeutic target; however, the potential interactions with other drugs and associated diseases should also be considered. According to the intensity of LDL-C reduction, we can differentiate between high-intensity statin therapy (atorvastatin 40-80 mg, rosuvastatin 20-40 mg), which achieves a reduction by approximately 50%, and moderate intensity therapy, which achieves a reduction by approximately 30%. Although statins demonstrate pleiotropic effects, the benefit of their use depends primarily on the achieved LDL-C reduction. Statins slightly reduce Lp(a), mildly increase HDL-C (by 1-10%), and lower triglycerides only slightly more in the case of intensive therapy (by 10-20%). ( 11 ) The most important adverse reaction to treatment is rhabdomyolysis. Measuring creatine kinase (CK) before introducing the drug is recommended. Routine monitoring of CK is not necessary, except in myalgia. If CK increases by <4 times, statin therapy does not have to be discontinued, even if the patient is experiencing muscle symptoms. In such cases, regular monitoring of symptoms and CK control are advised. If the complaints persist, statin therapy should be discontinued and the patient should be re-evaluated in 6 weeks. At that point, another statin can be introduced or the previous statin can be reintroduced at a lower dosage or taken every two days or one to two times a week. This is the first time the new guidelines emphasize the existence of the so-called nocebo effect of statins, i.e. statin-associated muscle symptoms, characterized by painful and sore muscles without an associated increase in CK or functional impairment. ( 12 ) In case of an increase in CK by >10 times, statin therapy should be discontinued and creatinine and CK should be monitored every two weeks. Drug treatment can continue if the patient shows no symptoms but CK has increased by <10 times, and CK should be measured again in 2-6 weeks. It is recommended to routinely measure ALT before starting statin treatment. This should be repeated again 8-12 weeks after introducing treatment or increasing the dose. If ALT increases by ≥3 times, the statin dose should be lowered or the treatment should be discontinued and ALT re-evaluated after 4-6 weeks. Re-attempting statin treatment is possible after ALT normalizes. The new guidelines highlight a significantly larger benefit of reducing CVR vs. mildly increased risk of diabetes with statin treatment. ( 13 ) Because of the above, regular monitoring of serum HbA1c or glucose is recommended when prescribing high statin doses or in persons with increased risk, including the elderly, persons with obesity, and persons with other evidence of insulin resistance. ## Cholesterol absorption inhibitors Ezetimibe is still the only drug in this class. The benefit of the synergistic effect of ezetimibe with statins, bile acid sequestrants, and PCSK9 inhibitors is emphasized. The new guidelines attribute more importance (class I recommendation) to ezetimibe in prescribing therapy after the maximum tolerable statin dose has failed to achieve the set goal, unlike the previous guidelines (class IIa). ## Proprotein convertase subtilisin/kexin type 9 inhibitors Proprotein convertase subtilisin/kexin type 9 inhibitors (PCSK9i) have been shown to be very effective in reducing CV events in patients with very high risk. Other than lowering LDL-C concentration by up to 60%, they also act by reducing serum Lp(a) by 25-30%. ( 2 , 3 ) The new guidelines assigned a higher class of recommendation (I A) to PCSK9i for secondary prevention of CVD and for primary prevention in patients with familial hypercholesterolemia and another additional major risk factor who failed to achieve target LDL-C value despite taking the maximum tolerable dose of statins and ezetimibe. The use of PCSK9i for primary prevention in persons with very high risk without familial hypercholesterolemia was assigned a lower class of recommendation (IIb). ## Fibrates The guidelines still question the benefits of treatment with fibrates, although studies reporting CVR reduction proportionate to the achieved non-HDL-C reduction are mentioned. The new guidelines give less importance to adverse effects of fibrates, including the risk of increased creatinine and homocysteine. Fibrates can be prescribed (recommendation class IIb) to persons with high CV risk who achieved their target LDL-C levels with statins, but still have serum triglycerides at >2.3 mmol/L. ## n-3 fatty acids The guidelines mention the result of a Cochrane meta-analysis that did not confirm the effect of n-3 fatty acids on CV mortality and morbidity, except in coronary events. ( 14 ) The guidelines comment on the results of REDUCE-IT, a study showing benefits of this therapy for the reduction of CV events frequency in high-risk patients with elevated triglycerides despite receiving statin treatment. ( 15 ) In comparison with fibrates, the use of icosapent ethyl at the dosage of 2×2 g per day received a higher class of recommendation (IIa) for the treatment of hypertriglyceridemia in persons with high or very high risk with a triglycerides concentration of 1.5-5.6 mmol/L despite receiving statin therapy. ## Treatment of dyslipidemias in different clinical settings Heterozygous familial hypercholesterolemia (FH) is described as a relatively frequent cause of premature atherosclerotic disease. FH should be suspected in diagnosing CVD in men aged <55 or women aged <60 years, adults with LDL-C >5 mmol/L, children with LDL-C >4 mmol/L, persons with tendinous xanthomata, or persons with relatives suffering from FH, premature CVD, or tendinous xanthomata. Diagnosis is established using the Dutch Lipid Clinic Network criteria, which take into consideration data from familial and personal medical history, physical examination, pre-treatment LDL-C values, and the potentially available results of genetic analysis. The score sum reflects the probability of this diagnosis. If possible, diagnosis should be confirmed by genetic testing because a confirmed mutation can be used for a cascade screening of other family members. Early screening for FH in children is recommended at the age of ≥5 years. In persons with FH and another additional major risk factor, and especially if they have already developed ASCVD, it is useful to introduce PCSK9i treatment if target LDL-C was not achieved with intensive statin and ezetimibe therapy. Persons with “isolated” FH are treated like any other persons with high CV risk. Homozygous FH is a rare, but very severe form of the disease, characterized by very high LDL-C concentration (>13 mmol/L), early and progressive ASCVD, and often ending with death at the age of <30 years. It is treated with intense hypolipemic therapy and apheresis. Addition of lomitapide can reduce LDL-C by up to 50%, reducing the frequency of the need for apheresis. ( 16 ) ## Persons with diabetes mellitus The new guidelines reclassified persons with diabetes mellitus according to CV risk categories and made their target LDL-C values stricter. Non-HDL-C and ApoB are recommended as secondary therapeutic goals in these patients as good indicators of burden with triglyceride-rich lipoproteins and residual particles. Statins are the first choice of treatment, but ezetimibe has been shown as very effective, causing a greater reduction in CV risk in persons with very high CV risk with diabetes mellitus vs. those without diabetes mellitus. ( 17 ) PCSK9i in persons with diabetes mellitus also cause an additional reduction of absolute risk for 3-year major CV events of 2.7% vs. people without diabetes mellitus. All of this is a consequence of increased absolute risk in this patient population. Persons with type 1 diabetes mellitus and good glycemic control sometimes have a “supernormal” lipid profile with low triglycerides and LDL-C, with HDL-C being at the upper limit of normal values or even slightly elevated. This is a consequence of subcutaneous insulin injections that promote the activity of lipoprotein lipase in adipose tissue and muscles, accelerating the rate of VLDL particle turnover. However, the changed composition of the resulting HDL and LDL particles can increase their atherogenic potential. ( 18 ) Statin treatment can be prescribed in young persons with type 1 and 2 diabetes mellitus (≤30 years) if there is evidence of target organ damage and/or LDL-C is >2.5 mmol/L, except in women planning to become pregnant. ## Persons with acute coronary syndrome The guidelines emphasize the importance of intensive and prolonged high-intensity statin treatment in patients with acute coronary syndrome (ACS), with the goal of a quick relative reduction of LDL-C by at least 50% and an absolute reduction of LDL-C <1.4 mmol/L. Ezetimibe should be added to statin treatment if this is not achieved with the maximum tolerable statin dosage within 4-6 weeks. If the set goal is not reached after an additional 4-6 weeks, addition of PCSK9i should be considered. If the patient was on the maximum tolerable dose of statin and ezetimibe even before ACS, PCSK9i introduction should be considered during hospital stay. In case of vascular event recurrence in the patient during the next two years (not necessarily ACS recurrence!), it is advisable to reduce LDL-C to <1.0 mmol/L. After hospitalization, patients with ACS should be referred to cardiovascular rehabilitation, which achieves better control of risk factors and significantly reduces mortality through a wholesome approach to reduction of total cardiovascular risk by exercising and educating patients on CVD, changing unhealthy lifestyle habits, and appropriate diet. ( 19 ) ## Ischemic stroke After suffering an ischemic stroke or transitory ischemic attack, patients have the same therapeutic goals as people with very high CV risk. With each reduction of LDL-C by 1 mmol/L, we reduce the risk of recurrent neurological events, myocardial infarction, and CV death by 12%. ( 20 ) ## Peripheral artery disease Based on the results of the FOURIER study, the new guidelines introduced PCSK9i into the therapeutic recommendations. ( 21 ) The benefits of using fenofibrate for the reduction of amputations in this population as well as for diabetic retinopathy progression are briefly mentioned. ( 22 ) ## Elderly persons Statin treatment of patients with ASCVD aged >65 is equally recommended as in young people. There is insufficient evidence to confirm the benefits of using statins in primary prevention in people older than 75, although the guidelines allow for that possibility in people with high or very high risk (IIb). ( 23 ) In case of kidney insufficiency or risk of interactions with other medicinal products, we should start with a low dose of statins and titrate it carefully. ## Conclusion The new guidelines for the treatment of dyslipidemias give priority to the clinical benefits of reducing LDL-C quickly and intensely, according to the principle of “the lower, the better”, especially in persons with high and very high cardiovascular risk. With such ambitious goals, combining basic hypolipemic drugs, high-intensity statins, ezetimibe, and PCSK9 inhibitors becomes more important. We are now tasked with putting extra effort into implementing these recommendations in our daily clinical practice and achieving good patient adherence with the prescribed therapy, in order to translate these excellent results from clinical trials to the real world.