The US Cardiovascular Arena-In Brief A Round-up of Trends, Statistics and Clinical Research

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Citation
US Cardiology, 2006;3(2):12-3
AHA Urges Action by New Congressional Leadership

The American Heart Association (AHA) in November urged the new congressional leadership to increase funding for cardiovascular disease research in order to help prevent a healthcare crisis emerging with the aging of the baby boomers.

With heart diseases and stroke affecting over 70 million adults in the US, rising levels of diabetes and obesity are predicted to have a profound effect on levels of mortality. Certainly, with levels of heart disease projected to grow 130% by 2050, levels of mortality are forecast to spiral, countering generations of increasing live expectancy. In addition, such trends will invariably increase healthcare burden, with costs for the treatment of cardiovascular disease forecast to grow 55% by 2025.

Raymond Gibbons, President of the AHA, stressed that a strong financial commitment to heart research would "save thousands of lives of baby boomers and help prevent a dramatic rise in [healthcare] costs".

Among the proposed action points highlighted by the AHA were an increase of funding for the Centers for Disease Control and Prevention of Heart Disease; legislation to authorise the US Food and Drug Administration (FDA) to better regulate the tobacco industry; and the creation of passage for HEART for Women Act, legislation aimed at improving the diagnosis and treatment of heart disease among females.

The message from the AHA comes at a time when research funding for the National Institutes of Health (NIH) has significantly lags cost inflation in medical research, with less than US$7 per capita spent on research of America's number one killer each year.

Elderly with Diabetes More Likely to Die of Cardiovascular Disease

Older people with diabetes are much more susceptible to fatality from cardiovascular diseases than non-diabetes sufferers.

These are the key findings of a recent study by Joshua Barzilay at Kaiser Permanente of Georgia and Emory University. The study comprised over 6,000 randomly selected adults over the age of 65 years. Of this group, approximately 9% were known to have diabetes, controlled by either insulin or oral medication.

Followed over an 11-year period, 40% of the study group died, with approximately 55% of fatalities cardiovascular-related. Once study statistics had been adjusted to reflect the presence of other factors that are linked to cardiovascular disease – including cholesterol levels and smoking prevalence – the study concluded that those with diabetes were over twice as likely to die of cardiovascular-related diseases compared with those without diabetes.

Notably, the risk of death was particularly high for patients with diabetes that used insulin to treat the disease. The findings highlight the need for further research to better understand the link between diabetes and cardiovascular risk, particularly among older demographics.

Predicting Likelihood of Deterioration Among Heart Failure Patients

A current phase III clinical trial is seeking to predict which heart failure patients are most likely to experience deterioration of the condition should they not receive any medical intervention.

Researchers conducting the trial at Montefiore Medical Center are using the tracer 123I-MIBG (metalodobenzylguanidine). This radiotracer is injected into the patient, and subsequently concentrates in nerves that control heart muscles. Single photon emission computed tomography (SPECT), a nuclear imaging procedure, is then used to determine the MIBG concentration in each patient's heart. Patients with the lowest evidence of MIBG are thought to be most prone to developing deteriorating heart failure conditions. Such patients may then be followed more closely over a subsequent period to see if medical intervention is required.

If successful, it is thought that the use of MIBG may be key in guiding treatment options, and thus maximising patient care. "MIBG may help [cardiologists] to identify sooner those patients who may need changes in their medical regimen, or even those who may need a heart transplant," noted Mark Travin, MD, the study's principal investigator.

HRT Linked to Heart Attack Teduction in Women Under 60 Years

Hormone replacement therapy could reduce heart attacks by about one-third in woman under the age of 60.

The study, conducted by researchers from Stanford and Cornell universities, analysed statistical data for over 39,000 women, uncovered that for women that began HRT treatment to relieve menopausal symptoms whilst in their 50s, the chance of cardiac death reduced significantly – over 32% – compared with those who received no treatment.

The study did note that for women over the age of 60 years results were not so conclusive. Indeed, for this age group it appeared that HRT increased the risk of heart attacks for the first year of treatment. After two years of treatment, however, the risk of heart attacks reduced below the level of women on either the placebo or on no treatment at all.

The results of this study further support a meta-analysis conducted by the same researchers in 2004, which concluded 39% fewer deaths among woman who started HRT treatment prior to the age of 60 years, compared with those not on HRT treatment.

The results could prove significant, as the Women's Health Initiative has previously reported a positive correlation between HRT treatment and the number of heart attacks. However, this research was based on a study group with a mean age of 63 years, and did not further examine age as a factor. These latest findings may prove important not only in indicating the cardiovascular benefits of HRT treatment in younger women, but may also help eradicate confusion among women, ignited by previous trial results.

Reversing the Hardening of Arteries

Recent research has revealed insight into the process by which blood vessels change with age, affecting their ability to contract and relax, ultimately undermining the effective circulation of blood.

The research, conducted at Linus Pauling Institute at Oregon State University, was funded by the National Institute on Aging, the American Heart Association, and the National Center for Complementary and Alternative Medicine.

A mechanism was found that fundamentally causes blood vessels in older patients to lose their elasticity, a process that is intrinsically linked to increasing levels of blood pressure and cardiovascular disease.

The fact that blood vessels lose approximately half their capability to contract and relax with age has been known for some time. However, until now, the reasons for this hardening have remained unclear.The research reports that in older blood vessels the process of cellular signalling breaks down and, whilst the vessels still have the ability to relax and contract – similar to when they were younger – they do not receive the same messages. The study noted that the enzymatic reaction critical to signaling, called phosphorylation, loses approximately half of its effectiveness. This has been attributed to the reduced activity of enzyme AKT.

The research that was conducted on animal models has yet to be tested in humans, but offers exciting potential to assist in the development of new therapies. "In laboratory testing, we were able to make blood vessels behave as if they were young again," noted Tory Hagen, MD, lead author of the study. It is thought that the compounds used to improve the signalling process could present an ideal base for the development of drug therapies.