Category: Cardiovascular Disease

Categories : Cardiovascular Disease Metabolic DisordersTags :

Top Medical Minds Gather to Address Diabetes Threat

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South Africa has seen the quickest and most alarming rise of diabetes on the continent; from an estimated 1.9 million people living with the condition in 2011 to 4.2 million by 2021 – with 7.5 million predicted to be afflicted by 20451. South Africa also has the fastest rising prevalence on the continent with an estimated 20% of the adult population either diabetic or pre-diabetic1. Globally, diabetes prevalence is predicted to rise by 46% between 2019 and 20452. It currently stands at some 537 million people worldwide1.

This emerged at the recently held annual Sanofi medical meeting, the Cardio-Metabolic Axis Forum from April 19th–21st in Cape Town. This was a meeting of leading endocrinologists, specialist physicians, nephrologists, diabetes-treating doctors, academics and Patient Advocacy Groups (PAGs).

Speaking at the conference, specialist physician and endocrinologist, Dr Landi Lombard – former editor of the South Africa Journal of Diabetes and Vascular Disease – told delegates that the risk of death associated with diabetes in cardiovascular conditions is more than twice that of people with non-diabetes, while in all-cause mortality, it’s just under twice that of a person living without diabetes. Of the estimated 537 million people living with diabetes globally, only about half are diagnosed, of whom 25% receive care, 12.5% achieve treatment targets, and 6% live a life free of diabetes-related complications1.

Dr Lombard said that the pandemic is being driven by poor lifestyle choices and diet, lack of exercise and widespread obesity in the population, so better healthcare worker communication and education of patients is vital to stem the tide of diabetes.

Professor Robert Ritzel of the Department of Endocrinology, Diabetology and Angiology at Schwabing Hospital in Munich, said the Pacific Islands and the Middle East led the world with diabetes prevalence at between 25 % and 40 %. He said what precipitated a surge in diabetes was the speed at which a nation changed from a traditional to a modern lifestyle. When this happened within a few years, diabetes prevalence was likely to range between 20% and 40%. However, when change occurred over many generations, it gave epidemiologists and clinicians time to adapt.

Lombard said one of the biggest challenges was what diabetologists called ‘therapeutic inertia’ which contributes to a patient living with sub-optimal blood sugar control for many years. This term embraced physician, patient and healthcare system factors, patient injection related factors, time and resource constraints among physicians and the lack of a proper healthcare system plan. He said that in people with Type 2 diabetes, the median time it takes for the disease to intensify while taking one or more anti-diabetic drugs is 2.9 years. However, the use of an injectable slowed intensification down to 7.2 years or more.

Reasons for failure to intensify treatment or progress to injectable therapies varied between specialist and primary care physicians but were mainly because of a patient fear of injection, too many injections, perceptions of this being a ‘last resort’ treatment, fear of weight gain, fear of low blood sugar, and poor communication with patients.

Lombard said even 1 year of poor blood sugar control in people with Type 2 diabetes could result in an increase in the cumulative incidence of kidney disease of 18%, neuropathy of 8%, retinopathy of 7% and a significantly increased risk of heart attack (67%), heart failure (64%), stroke (51%) and composite cardiovascular events (62%).

Professor Naomi ‘Dinky’ Levitt, former Head of Endocrinology and Diabetic Medicine at the University of Cape Town and Groote Schuur Hospital and Director of the Chronic Disease Initiative for Africa, highlighted gestational diabetes as one of the greatest challenges.

Described as the “doyenne” of endocrinology in South Africa (SA), Levitt said one third of women who have gestational diabetes go on to develop diabetes within 6 years of giving birth, so post-partum intervention is crucial.

According to Levitt, lifestyle interventions had about a 20% positive effect, mainly because new mothers were pulled in all directions by family, the baby, husband, and domestic and work needs.

She said that with 31.4% of SA women estimated to have developed gestational diabetes, it would be ideal to screen all pregnant women at 24 and 28 weeks. However, this would collapse the healthcare system because of the healthcare staffing demands, so the alternative was to focus on risk factors such as being over 30 years old or being overweight.

She said that focusing on women with gestational diabetes would have the greatest impact on the pandemic, as treatment can help avoid pre-eclampsia and improve foetal development, resulting in fewer admissions to the neonatal ICU.

Speaking on behalf of Sanofi the conference sponsor, Dr Asafika Mbangata said: “Sanofi puts patients first and the aim of the conference was to empower stakeholders with the right information to help make critical care decisions for patients by sharing the latest data on advancements in treatments and technologies, along with insights into global and local policy changes impacting diabetes care.”

“As we chase the miracles of science to improve people’s lives, we know we cannot shape the future of diabetes management without partnerships with healthcare professionals and other stakeholders. Collaboration across all medical disciplines is essential if we are to overcome this pandemic, and we’re hopeful the conference opened the door to future robust collaborative actions that improve patient outcomes,” concluded Dr Mbangata.

References

  1. Adapted from IDF Diabetes Atlas (10th edition). International Diabetes Federation. 2022. http://www.diabetesatlas.org/. Accessed 23 April, 2024.
  2. IDF Facts and Figures. https://idf.org/about-diabetes/diabetes-facts-figures/. Accessed 7 May, 2024.
Categories : Cardiovascular DiseaseTags :

High Prevalence of Hidden Brain Changes in People with Heart Disease

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A new analysis involving over 13 000 people has found changes to blood vessels in the brain that can increase the risk of stroke and dementia are common in people with a range of heart conditions, regardless of whether they have experienced a stroke.

The new research, published in Neurology®, the medical journal of the American Academy of Neurology, is the most comprehensive systematic review of ‘hidden’ brain changes in people with a range of heart conditions to date.

Lead author Dr Zien Zhou from The George Institute for Global Health said that identifying these changes could play an important role in choosing treatments for these patients.

“Although people with heart disease are two to three times more likely than the general population to have changes in their brain’s vascular system, they’re often overlooked, because these patients don’t routinely undergo brain imaging unless they have suffered a stroke,” he said.

“But it can make them more susceptible to the risk of brain bleeds from medications commonly used to treat or prevent blood clots – intracranial haemorrhage is a life-threatening complication with no proven treatment and a survival rate of less than 50 percent.”

Changes to blood vessels in the brain that can only be detected by brain imaging such as silent brain infarction (SBI) and cerebral small vessel disease (CSVD) are known to occur more commonly in older people or those who have hypertension.

While not sufficient to cause obvious neurological symptoms, they can result in subtle neurological deficits and increase the longer-term risk of stroke or dementia.

To determine the prevalence of these hidden or covert cerebrovascular changes in adults with atrial fibrillation, coronary artery disease, heart failure or cardiomyopathy, heart valve disease, and patent foramen ovale (a hole in the heart), George Institute researchers conducted a meta-analysis of 221 observational studies published between 1988 and 2022.

The findings showed that in people with heart disease:

  • approximately one third had any form of SBI
  • a quarter had lacune (small cavities where neural tissue has died after a previous blockage or leakage from small arteries)
  • two-thirds had white matter lesions (damage to the protective coating around nerve fibres)
  • a quarter had evidence of asymptomatic microbleeds in the brain tissue, and
  • over one half had brain atrophy (a shrinking of the brain due to loss of neurons or connections between neurons).

The prevalence of these brain changes was generally the same between those with and without a recent stroke and there were no apparent sex differences in the results.

Dr Zhou said the study also confirmed that heart disease is one of the main causes of these changes that reflect brain ‘frailty’.

“While several potential mechanisms of the association between heart disease and hidden cerebrovascular injury have been proposed, the two conditions share common risk factors such as ageing, hypertension, type 2 diabetes, hyperlipidaemia, and smoking,” said Dr Zhou.

“It’s possible that a gradual decline in cardiac output in some patients with heart disease might affect how much blood is reaching the brain tissue, contributing to vascular changes and cognitive dysfunction in these patients,” he added.

“It’s also possible that hidden brain changes and cognitive dysfunction are a consequence of tiny blood clots traveling to the brain through the arterial circulation after forming in the heart.”

Dr Zhou said that more research was needed to look at the exact causes of these brain changes and the implications for managing these patients.

“We need to know whether performing an additional MRI in those considered for anticoagulation therapy – which is required for most people with heart disease – would be cost-effective in terms of preventing unwanted side effects,” he said.

“But refining the risks of brain clots and bleeds from anticoagulants and using this information to make the best treatment choice could improve treatment safety for people with heart disease.”

Source: George Institute for Global Health

Categories : Cardiovascular Disease GeneticsTags :

Study Finds New Genetic Markers for Blood Pressure

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NIH-led study finds genetic markers that explain up to 12% of the differences between two people’s blood pressure.

Photo by CDC on Unsplash

National Institutes of Health researchers and collaborators have discovered over 100 new regions of the human genome, also known as genomic loci, that appear to influence a person’s blood pressure. Results of the study also point to several specific genomic loci that may be relevant to iron metabolism and a type of cellular receptor known as adrenergic receptors. 

The study, published in Nature Genetics, is one of the largest such genomic studies of blood pressure to date, including data from over 1 million participants and laying the groundwork for researchers to better understand how blood pressure is regulated. Such insights could point to potential new drug targets. 

“Our study helps explain a much larger proportion of the differences between two people’s blood pressure than was previously known,” said first author Jacob Keaton, PhD. “Our study found additional genomic locations that together explain a much larger part of the genetic differences in people’s blood pressure. Knowing a person’s risk for developing hypertension could lead to tailored treatments, which are more likely to be effective.” 

Hypertension often runs in families, meaning that there is a genetic component to developing the condition in addition to environmental contributions such as a high-salt diet, lack of exercise, smoking and stress.

To understand the genetics of blood pressure, the researchers combined four large datasets from genome-wide association studies of blood pressure and hypertension. After analysing the data, they found over 2000 genomic loci linked to blood pressure, including 113 new regions. Among the newly discovered genomic loci, several reside in genes that play a role in iron metabolism, confirming previous reports that high levels of accumulated iron can contribute to cardiovascular disease.  

The researchers also confirmed the association between variants in the ADRA1A gene and blood pressure. ADRA1A encodes a type of cell receptor, called an adrenergic receptor, that is currently a target for blood pressure medication, suggesting that other genomic variants discovered in the study may also have the potential to be drug targets to alter blood pressure. 

“This study shows that these big genome-wide association studies have clinical relevance for finding new drug targets and are needed to discover more drug targets as we go forward,” said Dr Keaton. 

From these analyses, the researchers were able to calculate a polygenic risk score, which combines the effects of all genomic variants together to predict blood pressure and risk for hypertension. These risk scores consider which genomic variants confer risk for hypertension and reveal clinically meaningful differences between people’s blood pressure. 

Polygenic risk scores have potential to serve as a useful tool in precision medicine, but more diverse genomic data is needed for them to be applicable broadly in routine health care. While the collected data was mostly from people of European ancestry, the polygenic risk scores were also applicable to people of African ancestry.

Source: National Institutes of Health

Categories : Cardiovascular Disease GeneticsTags :

Rare Longevity Mutation may Also Reduce Cardiovascular Disease Risk

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People with a rare longevity condition known as growth hormone receptor deficiency (GHRD) may also have possible cardiovascular health advantages. Also called Laron syndrome, GHRD, which is characterised by the body’s impaired ability to use its own growth hormone and results in stunted growth, has been linked in mice to a record 40% longevity extension and lower risks for various age-related diseases.

The risk of cardiovascular disease in individuals with GHRD has remained unclear until now, leading to the speculation that in people, this mouse longevity mutation may actually increase cardiovascular disease. In humans, unlike mice, GHRD is not associated with an extended lifespan.

The study, appearing in Med, is the latest product of an international collaboration spanning nearly 20 years between Valter Longo, professor of gerontology at the USC Leonard Davis School of Gerontology, and endocrinologist Jaime Guevara-Aguirre of the Universidad San Francisco de Quito, Ecuador.

Over the past two decades, Longo, Guevara-Aguirre and colleagues have examined the health and aging of people with the gene mutation that causes GHRD. This rare mutation, found in just 400 to 500 people worldwide, was identified in a group of Ecuadorians whose ancestors had fled Spain during the Inquisition more than three centuries ago. The mutation leaves them with ineffective growth hormone receptors and results in a type of dwarfism.

The team’s previous research has indicated that while GHRD/Laron syndrome reduces growth, it also appears to reduce the risk of several age-related diseases. Although the Ecuadorians with GHRD have a higher rate of obesity, they have a very low risk of cancer and Type 2 diabetes. They also appear to have healthier brains and better performance on tests of cognition and memory.

For the current study, the research team examined cardiovascular function, damage, and risk factors in GHRD subjects and their relatives. Researchers conducted two phases of measurements in Los Angeles and Ecuador, involving a total of 51 individuals, with 24 diagnosed with GHRD and 27 relatives without GHRD serving as controls.

Key findings from the study included:

  • GHRD subjects displayed lower blood sugar, insulin resistance, and blood pressure compared to the control group.
  • They also had smaller heart dimensions and similar pulse wave velocity (a measure of stiffness in the arteries) but had lower carotid artery thickness compared to control subjects.
  • Despite elevated low-density lipoprotein (LDL) levels, GHRD subjects showed a trend for lower carotid artery atherosclerotic plaques compared to controls (7% vs 36%).

“These findings suggest that individuals with GHRD have normal or improved levels of cardiovascular disease risk factors compared to their relatives,” said Longo, senior author of the new study. “Although the population tested is small, together with studies in mice and other organisms this human data provide valuable insights into the health effects of growth hormone receptor deficiency and suggest that drugs or dietary interventions that cause similar effects could reduce disease incidence and possibly extend longevity.”

Source: University of Southern California

Categories : Cardiovascular DiseaseTags :

A Model for Gentler Defibrillation for the Heart

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Photo by Stephen Andrews: https://www.pexels.com/photo/shallow-focus-of-electrocardiogram-9408866/

Using light pulses as a model for electrical defibrillation, Göttingen scientists developed a method to assess and modulate the heart function. This has paved the way for an efficient and direct treatment for cardiac arrhythmias. This may be an alternative for the strong and painful electrical shocks currently used.

Cardiac arrhythmias account for around 15-20% of annual deaths worldwide. In case of acute and life-threatening arrhythmias, defibrillators can be used to restart the regular beating of the heart. A strong electrical pulse brings cardiac activity to a brief standstill before it can be resumed in an orderly way. Whereas this treatment can save lives very effectively, the strong electrical pulses can also have negative side effects such as damage of the heart tissue or strong pain.

“We developed a new and much milder method which allows the heart to get back into the right rhythm,” says Stefan Luther, Max Planck Research Group leader at the MPI-DS and professor the University Göttingen Medical Center. “Our results show that it is possible to control the cardiac system with much lower energy intensity,” he continues.

To test their method, the scientists, from the Max Planck Institute for Dynamics and Self-Organization (MPI-DS) and the University Göttingen Medical Center, used genetically modified mouse hearts that can be stimulated by light. In this setting, a sequence of optical light pulses is triggered using a closed-loop pacing algorithm. Each pulse is triggered in response to the measured arrhythmic activity.

With this pacing protocol, the team was able to effectively control and terminate cardiac arrhythmias even at low energy intensities that do not activate the heart, but only modulate its excitability.

“Instead of administering a single high-energy shock to restore normal heart rhythm, we use our understanding of the dynamics of cardiac arrhythmias to gently terminate them.” explains Sayedeh Hussaini, first author of the study.

“This results in a subtle treatment method with far less energy per pulse, more than 40 times less compared to the conventional strategy” she reports.

The research team will also use these findings to improve the control of arrhythmias using electrical pulses. This may result in advanced defibrillators causing less pain and side-effects for patients.

Source: Max Planck Institute for Dynamics and Self-Organization

Categories : Cardiovascular Disease Environmental EffectsTags :

Air Pollution and Depression Linked with Cardiovascular Deaths in Middle Age

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A study in more than 3000 US counties, with 315 million residents, has suggested that air pollution is linked with stress and depression, putting under-65-year-olds at increased risk of dying from cardiovascular disease. The research was presented at ESC Preventive Cardiology 2024, a scientific congress of the European Society of Cardiology (ESC).1

“Our study indicates that the air we breathe affects our mental well-being, which in turn impacts heart health,” said study lead author Dr Shady Abohashemof Harvard Medical School, Boston, US.

According to the World Health Organization, air pollution is estimated to have caused 4.2 million premature deaths worldwide in 2019.2 Mental illness has also been linked with premature death.3 This study examined whether air pollution and poor mental health are interrelated and have a joint impact on death from cardiovascular disease.

The study focused on particles less than 2.5 micrometres in diameter, also referred to as fine particles or PM2.5. They come from vehicle exhaust fumes, power plant combustion, and burning wood, and present the highest health risk. To conduct the study, county-level data on annual PM2.5 levels were obtained from the Centers for Disease Control and Prevention (CDC).4 PM2.5 exposure was categorised as high or low according to World Health Organization (WHO) standards. The researchers gathered data on the average number of days (age-standardised) that county residents experienced mental health issues – including stress, depression, and emotional problems – from the CDC.5 Each county was then categorised into three groups based on these numbers. Counties in the top third reported the most days of poor mental health (PMH).4 Age-adjusted premature cardiovascular mortality rates (under 65 years of age) per county, were obtained from the CDC.6 County characteristics were sourced from the County Health Rankings project.

The study included 3047 US counties, representing 315 720 938 residents (with over 207 million aged 20 to 64 years and 50% females) in 2013. Between 2013 and 2019, some 1 079 656 (0.34%) participants died from cardiovascular disease before the age of 65 years. The researchers analysed the associations between pollution, mental health, and premature cardiovascular mortality after adjusting for factors that could influence the relationships.7

Counties with dirty air (high PM2.5 concentrations) were 10% more likely to report high levels of PMH days compared to counties with clean air (low PM2.5 concentrations). That risk was markedly greater in counties with a high prevalence of minority groups or poverty. The link between PMH and premature cardiovascular mortality was strongest in counties with higher levels (above WHO recommended levels: ≥10 µm2) of air pollution. In these counties, higher levels of PMH were associated with a three-fold increase in premature cardiovascular mortality compared to lower PMH levels. Further, one-third of the pollution-related risk of premature cardiovascular deaths was explained by increased burden of PMH.

Dr Abohashem said: “Our results reveal a dual threat from air pollution: it not only worsens mental health but also significantly amplifies the risk of heart-related deaths associated with poor mental health. Public health strategies are urgently needed to address both air quality and mental wellbeing in order to preserve cardiovascular health.”

The levels of pollution across ESC countries can be viewed in the ESC Atlas of Cardiology.

Source: European Society of Cardiology

References and notes

1The abstract ‘Air pollution associates with poor mental health and amplifies the premature cardiovascular death in the United States: longitudinal nationwide analysis’ will be presented during the session ‘Young Investigators Award – Population Science and Public Health’ which takes place on 26 April 2024.

2World Health Organization: Ambient (outdoor) air pollution.

3Byrne P. Meeting the challenges of rising premature mortality in people with severe mental illness. Future Healthc J. 2023;10(2):98-102.

4CDC PLACES databases.

5CDC Behavioral Risk Factor Surveillance System.

6CDC WONDER databases.

7The analyses were adjusted for calendar year and county characteristics such as demographics, median household income, unemployment rates, violent crime rates, education level, food environment index, rates of health insurance, level of mental health provision, level of primary care provision.

Categories : Cardiovascular DiseaseTags :

Study Finds Positive Effects with Anaesthetic Drug after Cardiac Arrest

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If a patient is successfully resuscitated after a cardiac arrest and circulation resumes, they are not out of the woods yet. A number of factors can influence whether and how they survive the trauma in the subsequent phase. But a multicentre study of 571 patients has shown that the administration of the anaesthetic midazolam has a positive effect.

In cases where the patient required anaesthesia after successful resuscitation, midazolam improved the chances of optimal oxygen saturation and CO2 levels in the blood. The risk of a renewed drop in blood pressure or a renewed circulatory arrest didn’t increase. “This specific group of patients who have been successfully resuscitated should definitely be included in the guidelines for pre-hospital anaesthesia. Midazolam has proven to have a particularly positive effect in this group,” concludes Dr Gerrit Jansen, lead author of the study, which was published in the journal Deutsches Ärzteblatt International.

In the event of a cardiac arrest, rapid intervention is essential: If first aiders carry out resuscitation measures in good time, the patient’s circulation can be restarted in the best-case scenario. “However, it’s often the case that the patient hasn’t yet regained consciousness,” explains Gerrit Jansen. In this phase, there are various factors that can affect the chances of survival and subsequent permanent limitations due to the circulatory arrest.

“Some patients display protective reflexes after resuscitation, such as coughing or defensive movements, which make the emergency responders’ work more difficult. They often have to perform extended airway management, for example by intubating the patient in the same way as during surgery. This frequently requires sedation or anaesthesia,” explains Jansen. Until now, there has been concern that anaesthetic drugs could have a negative impact on the circulatory system, which has only just been restored. According to the study, however, this is not the case.

Of the 571 people included in the study who survived a cardiac arrest and were admitted to hospital, 395 were sedated, 249 of them with midazolam. The chance that their blood oxygen saturation levels were in the optimal range following a cardiac arrest increased twofold when midazolam was administered. The chance that carbon dioxide was effectively exhaled increased by a factor of 1.6 with the drug. “Our statistical methods confirmed a correlation between these results and the administration of midazolam, without any indication of negative circulatory effects,” says Gerrit Jansen.

“The European guidelines of the European Resuscitation Council don’t yet set out any specific recommendations for possible anesthetic drugs,” explains Jansen. “The German guideline for pre-hospital anaesthesia for patients with cardiovascular risk doesn’t mention patients in cardiac arrest. We’ve therefore carried out pioneering research in this field, the results of which should be incorporated into the recommendations for the benefit of the patients.”

Source: Ruhr-University Bochum

Categories : Cardiovascular Disease Mental HealthTags :

Inflammation may Link Depression and Cardiomyopathy

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Coronary artery disease and major depression may be genetically linked via inflammatory pathways to an increased risk for cardiomyopathy, a degenerative heart muscle disease, researchers at Vanderbilt University Medical Center and Massachusetts General Hospital have found.

Their report, published in Nature Mental Health, suggests that drugs prescribed for coronary artery disease and depression, when used in combination, potentially may reduce inflammation and prevent the development of cardiomyopathy.

“This work suggests that chronic low-level inflammation may be a significant contributor to both depression and cardiovascular disease,” said the paper’s corresponding author, Lea Davis, PhD, associate professor of Medicine in the Division of Genetic Medicine and Vanderbilt Genetics Institute.

The connection between depression and other serious health conditions is well known. As many as 44% of patients with coronary artery disease (CAD), the most common form of cardiovascular disease, also have a diagnosis of major depression. Yet the biological relationship between the two conditions remains poorly understood.

A possible connection is inflammation. Changes in the levels of inflammatory markers have been observed in both conditions, suggesting that there may be a common biological pathway linking neuroinflammation in depression with atherosclerotic inflammation in CAD.

In the current study, the researchers used a technique called transcriptome-wide association scans to map single nucleotide polymorphisms (genetic variations) involved in regulating the expression of genes associated with both CAD and depression.

The technique identified 185 genes that were significantly associated with both depression and CAD, and which were “enriched” for biological roles in inflammation and cardiomyopathy.

This suggests that predisposition to both depression and CAD, which the researchers called (major) depressive CAD, or (m)dCAD, may further predispose individuals to cardiomyopathy.

However, when the researchers scanned large electronic health record databases at VUMC, Mass General, and the National Institutes of Health’s All of Us Research Program, they found the actual incidence of cardiomyopathy in patients with the enriched genes for (m)dCAD was lower than in patients with CAD alone.

One possible explanation is that medications prescribed for CAD and depression, such as statins and antidepressants, may prevent development of cardiomyopathy by reducing inflammation, the researchers concluded.

“More research is needed to investigate optimal treatment mechanisms,” Davis added, “but at a minimum this work suggests that patient heart and brain health should be considered together when developing management plans to treat depression or cardiovascular disease.”

Source: Vanderbilt University Medical Center

Categories : Cardiovascular Disease Environmental EffectsTags :

Hot Days may Drive Inflammation and Accelerate Cardiovascular Disease

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Photo by Fandy Much: https://www.pexels.com/photo/toshiba-outdoor-air-conditioner-unit-on-yellow-wall-14086132/

Short-term exposure to higher heat may increase inflammation and interfere with normal immune system functions in the body, which may, in turn, increase susceptibility to infections and accelerate the progression of cardiovascular disease, according to preliminary research be presented at the American Heart Association’s Epidemiology and Prevention – Lifestyle and Cardiometabolic Scientific Sessions 2024, March 18-21.

An inflammatory response that is longstanding (lasting weeks to months) or that occurs in healthy tissues is damaging and plays a key role in the build-up of plaque in the arteries. This may lead to atherosclerosis. Heat waves are known to promote inflammation, however, studies examining air temperature and biomarkers of inflammation have had mixed results.

“Most research only considers temperature as the exposure of interest, which may not be adequate to capture a person’s response to heat,” said lead study author Daniel W. Riggs, PhD, an assistant professor of medicine at the University of Louisville. “In our study, we used alternative measurements of heat in relation to multiple markers of inflammation and immune response in the body to investigate the short-term effects of heat exposure and produce a more complete picture of its health impact.”

Participants visited study sites in Louisville, during the summer months for a blood test, and researchers analysed the blood for multiple markers of immune system function. The researchers then examined associations between the markers of immune system function and heat levels, including temperature, net effective temperature (which factors in relative humidity, air temperature and windspeed) and the Universal Thermal Climate Index (UTCI) on that day. UTCI is a thermo-physiological model developed by the International Society of Biometeorology Commission that factors in temperature, humidity, wind speed and ultraviolet radiation levels, which was used to evaluate participant’s physical comfort.

The analysis found:

  • For every 5°F (2.8°C) increase in UTCI (in this study, the equivalent of going from a day with no thermal stress to a day with moderate thermal stress, Riggs said), there was an increase in blood levels of key inflammatory markers: monocytes (4.2%), eosinophils (9.5%), natural killer T-cells (9.9%) and tumour necrosis factor-alpha (7.0%). These immune molecules indicate activation of the body’s innate immune system, which spurs a fast and non-specific inflammatory response throughout the body to protect against pathogens and injury.
  • A decrease in B-cells (-6.8%), indicating the body’s adaptive immune system that remembers specific viruses and germs and creates antibodies to fight them, was lowered.
  • A lesser impact on the immune system was found when heat was measured by average 24-hour temperature or by net effective temperature, which incorporates humidity and wind but not sunshine.

“Our study participants only had minor exposure to high temperatures on the day of their blood test, however, even minor exposure may contribute to changes in immune markers,” Riggs said. “With rising global temperatures, the association between heat exposure and a temporarily weakened response from the immune system is a concern because temperature and humidity are known to be important environmental drivers of infectious, airborne disease transmission. Thus, during the hottest days of summer people may be at higher risk of heat exposure, they may also be more vulnerable to disease or inflammation.”

Adults over 60 years and adults with existing cardiovascular disease are particularly at risk for heat-related cardiovascular events and deaths, Riggs explained.

“It’s important for physicians to communicate with patients about the risk of adverse health effects from heat exposure. For example, cardiologists could conduct customised consultations and assessments to increase patient awareness about their susceptibility to the effects of high temperatures. Also, changes to treatment regimens may be important to consider to address other risks. For example, some medications could make people more susceptible to heat-related illness or some may not be as effective when the body is exposed to high temperatures,” Riggs said.

Source: American Heart Association

Categories : Cardiovascular DiseaseTags :

At-home Nasal Spray for Episodes of Arrhythmia

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A clinical trial led by Weill Cornell Medicine investigators showed that a nasal spray that patients administer at home, without a physician, successfully and safely treated recurrent episodes of a condition that causes arrythmia. The study, published in the Journal of the American College of Cardiology, provides real-world evidence that a wide range of patients can safely and effectively use the experimental drug etripamil to treat recurrent paroxysmal supraventricular tachycardia (PSVT) episodes at home. For many, this could spare the need for repeated hospital trips for more invasive treatments.

The study is the latest in a series of studies by lead author Dr James Ip, professor of clinical medicine at Weill Cornell Medicine and a cardiologist at New York-Presbyterian/Weill Cornell Medical Center, and colleagues to demonstrate the potential of nasal spray calcium-channel blocker etripamil as an at-home treatment for PSVT.

Patients with PSVT experience sudden and recurrent rapid heart rhythms triggered by abnormal electrical activity in the upper chambers of the heart.

Though the episodes are not commonly life-threatening, they can be frightening and cause shortness of breath, chest pain, dizziness or fainting and lead to frequent emergency department visits. Treatment for PSVT often requires hospitalisation to receive intravenous medication. Some patients undergo cardiac ablation.

Dr Ip and colleagues previously showed that almost two-thirds of patients with PSVT who took one or more doses of the calcium channel blocker etripamil without a physician present experienced symptom relief on average in 17 minutes.

The latest study builds on those findings, showing that etripamil is safe and effective under more real-world circumstances in a larger patient population, and could be safely used to treat multiple episodes of PSVT.

The new study enrolled 1116 patients at 148 sites in the United States, Canada and South America. It did not require a pretest dose supervised by a physician as the previous studies did. It also included patients with a history of atrial fibrillation or atrial flutter, who were excluded from the previous studies. Patients monitored their heart for one hour with a home electrocardiogram monitor after self-administering the first dose, took an additional dose if necessary, and were allowed to self-treat up to four PSVT episodes with etripamil. Two-thirds of the patients experienced relief within an hour, and the average time needed for symptom relief was 17 minutes. Mild, temporary nasal symptoms such as runny nose, nasal congestion or discomfort, and bloody nose were common after the first use of etripamil but became less common with subsequent use.

Source: Weill Cornell Medicine