CORRESPONDENCE

Premature cardiovascular deaths

To the Editor: Sudden death often, but not always, affects young and ostensibly healthy people. The effect on families and friends may be devastating. It is imperative that the cause of the sudden death is determined because other members of the family may be affected with the same heritable condition. We were pleased to read about the important work done on genetic testing for arrhythmogenic disorders,^[1,2] and wish to broaden the consideration of causal conditions to several metabolic conditions that should be recognised on clinical and biochemical grounds, especially familial hypercholesterolaemia (FH). FH, despite its high prevalence in South Africa due to founder effects, is often not diagnosed, and treatment is often started late in life, with many patients not achieving their low-density lipoprotein (LDL) cholesterol target.^[3]

FH is not rare; a global call for action was made to identify people with this heritable condition as, in most cases, it can be treated with safe and affordable medication.^[4] The average age of a first cardiovascular event in subjects with FH was 45 years in a local study, but events may occur at an even younger age.^[5] Anecdotally, sudden death occurred as a result of an acute myocardial infarction in a 23-year-old male who had not previously been diagnosed with (heterozygous) FH, despite a family history of premature heart disease. Women with heterozygous FH may also die prematurely: a 26-year-old woman died as a result of an acute myocardial infarction within hours of the delivery of her first child, and a 28-year-old woman with a short history of angina pectoris also died suddenly following a myocardial infarction. Homozygous FH is associated with cardiovascular deaths at an even younger age, but the prognosis has improved with modern treatment.^[6] Other lipoprotein disorders that may present like homozygous FH include phytosterolaemia, autosomal recessive hypercholesterolaemia dysbetalipoproteinaemia^[7] and very low concentrations of high-density lipoprotein (HDL) cholesterol.^[8]

There are also connective tissue disorders affecting the arterial system that may result in rupture and/or thrombosis with haemorrhage, dissection, or coronary or cerebral arterial events.^[9] Toxins may also play a role, including cannabis, cocaine and even psychotropic drugs.^[10] In the context of a sudden (cardiac) death in athletes, there are several additional considerations,^[11] including commotio cordis.^[12]

We hope that a sudden, unexpected death will prompt a thorough clinical, biochemical, pathological and genetic investigation to identify its cause so as to prevent recurrences of the same tragedy in other family members, by preventive treatment, preparation for resuscitation and to provide closure for the family of the deceased. FH is an important treatable and preventable cause of sudden death.

A D Marais

Division of Chemical Pathology, Department of Pathology, Faculty of Health Sciences, University of Cape Town, South Africa david.marais@uct.ac.za

D J Blom

Division of Lipidology, Department of Medicine, Faculty of Health Sciences, University of Cape Town, South Africa

F J Raal

Carbohydrate and Lipid Metabolism Research Unit, University of the Witwatersrand, Johannesburg, South Africa; Division of Endocrinology and Metabolism, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa

References

1. Stroh van Deventer B, du Toit-Prinsloo L, van Niekerk C. Postmortem testing in young individuals: What the clinical medical practitioners need to know. S Afr Med J 2022;112(12):886-889. https://doi.org/10.7196/samj.2022.v112i12.16800        [ Links ]

2. Stroh van Deventer B, du Toit-Prinsloo L, van Niekerk C. Cardiovascular death: What do the genes say? S Afr Med J 2022;112(12):885. https://doi.org/10.7196/samj.2022.v112i12.16801        [ Links ]

3. Marais AD, Blom DJ, Raal FJ. Familial hypercholesterolaemia in South Africa: A reminder. S Afr Med J 2021;111(8):700-701. https://doi.org/10.7196/samj.2021.v111i8.15782        [ Links ]

4. Wilemon KA, Patel J, Aguilar-Salinas C, et al. Reducing the clinical and public health burden of familial hypercholesterolemia. A global call to action. JAMA Cardiol 2020;5(2):217-229. https://doi.org/10.1001/jamacardio.2019.5173        [ Links ]

5. Firth JC, Marais AD. Familial hypercholesterolaemia: The Groote Schuur Hospital experience. S Afr Med J 2008;98(2):99-104.         [ Links ]

6. Thompson GR, Blom DJ, Marais AD, Seed M, Pilcher GJ, Raal FJ. Survival in homozygous familial hypercholesterolaemia is determined by the on-treatment level of serum cholesterol. Eur Heart J 2018;39(14):1162-1168. https://doi.org/10.1093/eurheartj/ehx317        [ Links ]

7. Marais AD. Dysbetalipoproteinemia: An extreme disorder of remnant metabolism. Curr Opin Lipidol 2015;26(4):292-297. https://doi.org/10.1097/mol.0000000000000192        [ Links ]

8. Schaefer EJ, Santos RD, Asztalos BF. Marked HDL deficiency and premature coronary heart disease. Curr Opin Lipidol 2010;21(4):289-297. https://doi.org/10.1097/mol.0b013e32833c1ef6        [ Links ]

9. Vanakker OM, Hemelsoet D, de Paepe A. Hereditary connective tissue diseases in young adult stroke: A comprehensive synthesis. Stroke Res Treatment 2011:712903. https://doi.org/10.4061/2011/712903        [ Links ]

10. Morentin B, Callado LF. Sudden cardiac death associated to substances of abuse and psychotropic drugs consumed by young people: A population study based on forensic autopsies. Drug Alcohol Depend 2019;201:23-28. https://doi.org/10.1016/j.drugalcdep.2019.03.021        [ Links ]

11. Schmied C, Borjesson M. Sudden cardiac death in athletes. J Internal Med 2013;275(2):93-103. https://doi.org/10.1111/joim.12184        [ Links ]

12. Link MS. Commotio cordis: Sudden death due to chest wall impact in sports. Heart 1999;81(2):109-110. https://doi.org/10.1136/hrt.81.2.109        [ Links ]