Lipoprotein(a) and Heart Disease: Genetic inheritance? What can we do?
Cardiovascular disease is a disease of the heart and blood vessels that can lead to angina, heart attack, or stroke. There has been a 30-year (1980-2010) decline in mortality rate of cardiovascular disease (CVD), however, since 2010 the National Center for Health Statistics determined that CVD deaths have started to increase (Volgman AS, 2019). In more recent years, the leading cause of death in 2016 was CVD at 43% and stroke at 17%. Interestingly, over 60% of CVD deaths were plaque related (Volgman AS, 2019). As the heart pumps blood throughout the body (approximately 5.0 L/min), plaque buildup decreases the blood vessel diameter through which blood must pass in order to supply specific areas in the body. This is particularly worrisome in individuals with hypertension (high blood pressure) because of the increased risk for plaque fissuring (separation), dislodging, and resulting in an embolism (blockage).
Given that CVD is a major problem in the US, it is important to first identify how the problem might arise prior to considering preventative measures. Studies have already suggested a genetic component of increased risk for CVD, namely lipoprotein(a) or Lp(a). A lipoprotein is a soluble protein that can be combined with lipids (fats) while in the blood stream. Lp(a) is rather peculiar, in that it is a pathogenic (disease causing) molecule (McCormick, 2004) and has been compared to a low-density lipoprotein (LDL) – more commonly referred to as “bad” cholesterol (LDL: The "Bad" Cholesterol, 2019). Of note, even though Lp(a) is compared to LDL, they are not one in the same. Meaning, while statins may decrease LDL levels, this medication has the opposite effect on Lp(a) (Tsimikas S, 2017).
Individuals with an inherited Lp(a) intron gene are at a 20% risk for CVD. The problem with these individuals is that proper exercise regimes may not necessarily improve their odds of cardiovascular related anomalies (Volgman AS, 2019). That being said, there is also a racial/ethnic component to at-high risk people (Tsimikas et al., 2018). The highest Lp(a) levels have been detected in South Asians at 35% as well as people from Filipin and Vietnam, followed by people of African descent at 30% (Volgman AS, 2019).
Luckily, certain medication (i.e. niacin) which can help manage risks for pathogenicity by lowering dangerously high levels of Lp(a) by about 30% (Volgman AS, 2019). But the question ultimately become: what is a sufficiently high percentage that would decrease risk for heart attack or stroke – 80? 90? In short, medicine does not yet know. Fortunately, current studies are exploring drugs that may decrease Lp(a) levels by about 80%. Meanwhile, physicians may recommend being more mindful about decreasing LDL consumption (i.e. full-fat yogurt, beef, pork, poultry) (Department of Health & Human Services, 2014).
A main biomedical ethical consideration associated with CVD patients is justice. Given that people of ethnic/racial backgrounds are at higher risk for disease than their Caucasian counterparts, it is important to ensure that participants who directly contribute to the statistics have equal represented. What recommendations might you have towards improving inclusivity?
Reference:
Department of Health & Human Services. (2014). Cholesterol - healthy eating tips. Retrieved from https://www.betterhealth.vic.gov.au/health/conditionsandtreatments/cholesterol-healthy-eating-tips.
LDL: The "Bad" Cholesterol. (2019). Retrieved from https://medlineplus.gov/ldlthebadcholesterol.html.
McCormick SP. (2004). Lipoprotein(a): biology and clinical importance. Clin Biochem Rev, 25(1): 69–80.
Tsimikas S. (2017). A test in context: lipoprotein (a): diagnosis, prognosis, controversies, and emerging therapies. J Am Coll Cardiol, 69(6): 692-711.
Tsimikas S, Fazio S, Ferdinand KC, Ginsberg HN, Koschinsky ML, Marcovina SM, ... & Santos RD. (2018). NHLBI working group recommendations to reduce lipoprotein (a)-mediated risk of cardiovascular disease and aortic stenosis. J Am Coll Cardiol, 71(2): 177-192.
Volgman AS. (2019). Lipoprotein "Little A" Can Cause More Than a Little Damage to the Heart. Retrieved from https://blogs.scientificamerican.com/observations/lipoprotein-little-a-can-cause-more-than-a-little-damage-to-the-heart/.
Georgi,
ReplyDeleteThe ethical value of justice in terms of racial/ethnic groups having access to the same medical treatments, procedures and care has been a problem for a long time. This ethical value can be seen and is associated with a host of disorders including CVD. My first recommendation for improving access to medication and treatment for CVD is through education and by improving awareness. On occasion, patients do not have access to medical procedures and treatments because they do not have the knowledge that they exist. These patients do not know the options that are available for them and at times do not go to see a physician to learn about the options. In order to raise awareness, there have been initiatives in the past with the goal of increasing knowledge by teaching about the misconceptions of CVD. Raising awareness can be done by promoting public health outreach educational programs as well as teaching healthy lifestyle behaviors and about the misconceptions about CVD (Koniak-Griffin & Brecht, 2015). My second suggestion would be to provide the medication based on a sliding scale determined by individual patient’s income so that it is available for everyone at a reasonable cost. It is common that individuals do not go to see a physician because they do not have the financial means to do so. If individuals of a lower socio-economic status can afford the medication, then they would have an increase access to it.
Koniak-Griffin, D., & Brecht, M. L. (2015). Awareness of cardiovascular disease and preventive behaviors among overweight immigrant Latinas. The Journal of cardiovascular nursing, 30(5), 447.