However, a third of the people with HIV in San Francisco whose cause of death was attributed to sudden cardiac arrest actually died of drug overdoses.
An American study, whose results have been published in The New England Journal of Medicine, has revealed that people with HIV in San Francisco (USA) are more than twice as likely to die from sudden cardiac death than the population general, and that they are more prone to developing fibrosis, a factor that can increase the susceptibility of dying from sudden cardiac arrest. In addition, the study found that a third of the sudden deaths that were initially attributed to cardiac events among the population with HIV were caused by drug overdose.
Sudden cardiac death occurs when an electrical malfunction occurs in the heart, following an alteration of the heart rhythm (arrhythmia). Risk factors are previously diagnosed cardiovascular disease, heart attack, and arrhythmias, but sudden cardiac arrest often kills people without previously identified risks. Sudden cardiac arrest can be treated with a defibrillator, which would cause an electric shock to re-regulate the heart rhythm, or with the use of cardiopulmonary resuscitation. The incidence of sudden cardiac death is significantly more common in people with HIV and is often associated with drug overdose or kidney failure, however this has not been clearly determined. In many cases, these deaths occur in people who did not have a history of heart problems.
The emergency medical personnel usually perform the evaluation of the person with cardiac arrest in the place where it occurs when they are not admitted to a hospital. The World Health Organization (WHO) establishes as a criterion so that it can be assumed that the cause of death is cardiac that the death occurred in the first hour of presenting symptoms or if the deceased has been seen alive without symptoms in the 24 hours in advance. However, deaths that occur outside the hospital setting are rarely investigated, so it is often a guess whether a sudden death was actually due to cardiac causes.
To shed some more light on this question, a team of researchers at the University of California, San Francisco (USA) conducted the study that examined sudden deaths in San Francisco between 2011 and 2016 in the context of HIV. The aim was to determine the genetic, molecular or other risk factors that led to sudden cardiac death - one of the leading causes of death from cardiovascular disease - to predict which people were most likely to benefit from preventive interventions, such as implantation. of a cardiac defibrillator.
In an initial analysis, published in 2012, researchers indicated that a disproportionate number of deaths - more than four times as many - whose cause had been attributed to sudden cardiac death occurred in people with HIV. But in that analysis the cause of death was presumed without confirmation through autopsy. This was the reason that led the team of researchers to delve deeper into the investigation of death from sudden cardiac arrest in people with HIV.
The researchers conducted a comprehensive review of San Francisco emergency and medical records of people who died outside the hospital with cardiac symptoms and performed a full autopsy on the bodies. The post-mortem study also included a blood test, as well as a histological and toxicological analysis, with the aim of determining the true underlying causes of sudden death in people with HIV.
Between 2011 and 2014, a total of 610 people with HIV between the ages of 18 and 90 died unexpectedly from any cause in San Francisco. Of these deaths, 109 were the result of sudden cardiac arrest that occurred outside of a hospital. Cause of death was determined by health workers or emergency medical personnel at the scene of death. The study did not provide data on whether people who died of cardiac arrest were on antiretroviral treatment or what other conditions they suffered from. However, these people were not in palliative care or considered to have end-stage illness, nor did they have a medical history of having recently received a serious diagnosis.
After reviewing medical records and performing autopsies on all but one of the cases, the researchers determined that 48 cases met the criteria for sudden cardiac death. But less than half of them (22) were the result of a cardiac arrhythmia, or erratic heartbeat. Arrhythmia is the cause of death most associated with conventional heart problems, such as coronary artery disease or a damaged or enlarged heart.
Another 16 deaths (34%) among people with HIV were actually the result of a drug overdose, as toxicological tests showed. By comparison, 13% of suspected sudden cardiac arrest deaths among people without HIV were due to a drug overdose. Also, people with HIV were more likely to have cardiac fibrosis (scarring of the heart tissue as a result of previous damage) than people without HIV.
Overall, there were 53 sudden cardiac deaths per 100,000 person-years among people with HIV, compared with 24 among people without HIV, or more than double the focus. associated with cardiac arrhythmia, people with HIV were 87% more likely to be the cause of their death.
The researchers stress that, in addition to drug overdoses, the actual causes of deaths initially attributed to heart conditions include pulmonary embolism, stroke, infection, diabetic ketoacidosis, gastrointestinal bleeding, kidney failure, seizures and ruptured aneurysm.
On the other hand, they also highlight that chronic inflammation in people with HIV persists even when they are receiving antiretroviral treatment and have an undetectable viral load. In turn, this ongoing inflammation can increase the likelihood of developing clinical events, including general mortality and cardiovascular events, kidney disease, and neurological disease. Currently, people with HIV are known to have significantly higher rates of acute myocardial infarction, heart failure, peripheral arterial disease, and ischemic stroke compared to the general population.
The researchers also found higher levels of interstitial fibrosis - in which collagen is deposited around clusters of heart cells - in the heart tissue of people with HIV. Similar fibrosis has been observed in the lymph nodes, liver, and kidneys in previous HIV studies.
In conclusion, the team of researchers hypothesize that cardiac fibrosis –associated with an increased risk of sudden death- may probably be the result of the systemic impact of chronic HIV infection. Identifying people with HIV who may be at risk is critical to preventing deaths from sudden cardiac arrest. In addition, therapeutic strategies to reduce fibrosis in people with HIV will be an important area of research in the future.
Source: POZ / Elaboración propia (gTt-VIH).
References: Tseng ZH, M.D., Moffatt E, M.D., Kim A, M.D., Vittinghoff E, Ph.D., Ursell P, M.D., Connolly A, M.D., et al. Sudden Cardiac Death and Myocardial Fibrosis, Determined by Autopsy, in Persons with HIV. June 17, 2021 N Engl J Med 2021; 384:2306-2316 DOI: 10.1056/NEJMoa1914279