Monday, September 30, 2013

What Is Resistant Hypertension?

A person is said to have resistant hypertension if this person’s hypertension does not respond to a 3-drug combination therapy that includes a diuretic. A diuretic is any substance that promotes the production of urine. It is used to treat heart failure, liver cirrhosis, hypertension and certain kidney diseases.

In Singapore, about 25 percent of adults have high blood pressure, based on the 2010’s National Health Survey. Many of them take 2 to 3 types of hypertensive medications to control their blood pressure. About 3 to 5 percent of these patients, usually elderly, have resistant hypertension.

The 3 most common causes of resistant hypertension are: patients’ noncompliance to medications, secondary hypertension (usually from overactive adrenal glands) and fluid retention (usually expansion from kidney failure). More importantly, doctors have to ensure that what appears to be resistant hypertension is not actually pseudo hypertension or white coat hypertension.

Pseudohypertension is when blood pressure measurements are high but the blood pressure is actually normal. It is not very common, and is usually found in older patients. White coat hypertension is a scenario in which a person has high blood pressure readings only when he or she is in medical setting. The blood pressure can be normal when measuring at home.

Persistent uncontrolled hypertension is a significant risk factor for stroke and heart disease. Studies have shown that each incremental increase of 20 mmHg in systolic blood pressure and 10 mmHg in diastolic (minimum) blood pressure above normal levels directly correlates to a doubling of the risk of death from cardiovascular disease over a 10-year period.

It was also found that a lowering of 5 mmHg in blood pressure results in a decline of 14 percent in the risk of stroke, a 9 percent in the risk of heart disease and a 7 percent in the risk of death.

Sometimes, targeting the kidneys can treat high blood pressure. A minimally invasive procedure is used to remove the renal sympathetic nerves so that kidney would stop reacting excessively and the blood pressure would drop.

Such procedure, however, might not be suitable for all patients. It can only be employed for patients with normal kidney function. The kidney arteries need to be relatively disease-free and more than 4mm in diameter. Its main complications are damage to the kidney arteries or side effects from using contrast agents.

The National Heart Centre Singapore carried out the first such procedure in September 2011. Studies in Europe and Australia have shown that patients who have been followed up for 2 years without unfavorable effects.

Monday, September 23, 2013

Simple CPR Could Have Long-Term Benefit!

CPR (Cardiopulmonary resuscitation) is an emergency procedure for a person who has cardiac arrest. Its purpose is to preserve intact brain function until further measures to restore spontaneous blood circulation and breathing. A standard CPR normally involves chest compression together mouth-to-mouth or mouth-to-nose resuscitation.

However, researchers from Descartes University in Paris, France and other institutions from Seattle (USA) and Sweden reported that people suffering cardiac arrest were less likely to die in subsequent years when bystanders performed simple CPR with chest compressions only. The findings were published online on December 10, 2012 in the journal ‘Circulation’.

This was more or less in line with the recommendation by the American Heart Association (AHA): a simpler form of CPR from bystanders is better than no aid at all. However, such recommendation does not apply to CPR performed in hospital or in community by medical personnel or people who are proficient in rescue breathing. Such recommendation also applies only to adult victims.

Data from 2 randomized trials that were reported in the ‘New England Journal of Medicine’ in 2010 were examined. More than 3,200 adults were involved. These victims had cardiac arrest likely due to heart disease problems rather than trauma, suffocating or drowning. Bystanders were instructed by dispatchers via phone to use either the standard or compression only form of CPR.

The researchers were able to follow 78 percent of the participants on longer-term outcomes. The one-year survival rate was found to be about 12 percent for chest compression alone and about 10 percent for standard CPR. Mortality was 9 percent lower in the compression-only group than in the standard CPR group, after adjusting for different factors. The survival benefit persisted over 5 years.

Nevertheless, the study only tracked survival and it could not assess patients’ function level or quality of life. Moreover, the original trials employed in the study were not meant for tracking long-term outcomes.

While there are concerns that victims who collapse of non-cardiac causes might not get the oxygen they need with the compression-only approach, the researchers confirmed they did not observe evidence of harm among those for whom oxygenation and ventilation might in theory be more important.

Victims would require fresh oxygen through mouth-to-mouth resuscitation only if they have been down for a longer or unknown period of time, according to other health experts. The majority of cardiac arrest events are likely caused by heart disease problems. It is most probably that some oxygen still remains in the blood when the victim’s heart has stopped for a short period of time. So proceeding with chest compression only should be beneficial for most circumstances.

Monday, September 16, 2013

How Is Insufficient Sleep Related To Weight Gain?

Obesity epidemic has been a hot issue for many industrial nations, and lately also for developing countries. World Health Organization (WHO) indicated that more than 1.4 billion adults aged 20 and older were overweight in 2008. The figure had nearly doubled since 1980.

Overweight or obesity can lead to numerous chronic diseases including diabetes, heart disease, hypertension (high blood pressure) and stroke. At least 2.8 million adults die every year because of obesity or overweight.

Scientists have suspected that there is a strong correlation between sleep deprivation and weight gain, as indicated by various studies over the years. For instance, one study reported that people who slept less than 6 hours a night had their body mass index (BMI) increased more than those who slept 7 to 8 hours. In another 16-year study, women slept 5 hours or less gained more weight than those who slept 7 hours a day. Nevertheless, the actual reasons behind these had yet to be unveiled.

BMI is a simple and common indicator to determine whether a person is overweight, obese or of normal weight. It is calculated by dividing the weight in kilos by the square of height in meters.

On August 6, 2013, researchers from the University of California in Berkeley reported in journal ‘Nature Communications’ that they had found a brain mechanism that could explain how sleep deprivation might lead to the development and maintenance of obesity.

In the study, researchers used magnetic resonance imaging (MRI) scans to spot changes in the brain activity of 23 participants. These participants had their head scanned twice: once after a full night of sleep and once after being deprived their shut-eye for a night. Their brain activity measured the next day as they selected items and portion sizes from pictures of 80 different food types.

Impaired activity in regions of the cortex that evaluate appetite and satiation was found among the sleep-deprived participants. Simultaneously, there was a boost in areas associated with craving. The study also found that high calorie foods became more desirable to the sleep deprived participants.

According to researchers, the link between sleep loss, weight gain and obesity can be explained by the impaired brain activity found in regions that control good judgment and decision making coupled with amplified activity in more reward-related brain regions.

They also believed that having enough amounts of sleep regularly might be a good way to promote weight control, which is achieved by priming the brain mechanisms governing appropriate food choices.

Monday, September 09, 2013

Has Outpatient Care Controlled Heart Disease Risk Factors?

While focusing on improving the quality of inpatient hospital care is critical to give the patients the best and appropriate treatments, the quality of outpatient care is equally important to have a better control of heart disease risk factors including hypertension, diabetes, and smoking.

According to a study conducted by American researchers from Duke University in Durham and Edward Heart Hospital in Naperville, the control of heart disease risk factors varies widely among outpatient practices. The findings were presented at the American Heart Association's Quality of Care and Outcomes Research Scientific Sessions 2013.

Electronic health records of 115,737 patients in 18 primary care and cardiology practices participating in The Guideline Advantage were compared from January 1, 2010 to March 31, 2012.

Among the participants, 65,212 (56.3 percent) had hypertension, 67,826 (58.6 percent) had hyperlipidemia, 8,815 (7.6 percent) had diabetes mellitus, 3,073 (2.7 percent) had a history of a stroke or transient ischemic attack, and 23,624 (20.4 percent) had coronary artery disease.

Guideline Advantage, a collaboration of the American Cancer Society, American Diabetes Association and American Heart Association, is a nationwide quality improvement program for outpatient care. It collects data through existing electronic health records to report adherence to established guidelines with an aim to reducing risks for chronic diseases.

In the study, the researchers found that the percentage of people aged 18 through 85 years with hypertension under control (less than 140/90 mm Hg) ranged between 58.7 percent and 75.1 percent; the percentage of diabetic patients aged 18 through 75 years with hyperlipidemia control (bad low density lipoprotein cholesterol under 100 mg/dL) was between 53.8 percent and 100 percent; and the percentage of patients aged 18 years and older screened for smoking, and receiving a tobacco cessation intervention, was between 53.8 percent and 86.1 percent.

The findings did identified multiple opportunities for improving quality of outpatient care for cardiovascular prevention. Outpatient care providers can use them to compare their standard with their peers on nationally derived measures of quality and learn to improve in collaboration with others instead of alone.

Monday, September 02, 2013

Would Mediterranean Diet Benefit Elderly?

Mediterranean diet is a nutritional recommendation that is built on high proportion of olive oil, fruits, vegetables, legumes, nuts, whole grains and fish. It follows closely the traditional dietary patterns of people living in the areas surrounding the Mediterranean Sea including Greece, southern Italy and Spain, and is also characterized by a moderate consumption of wine, dairy products, and poultry, together with a low consumption of red meat, sweet beverages, creams, and pastries.

Being low in saturated fat and high in monounsaturated fat and dietary fiber, Mediterranean diet has been praised for increasing longevity and preventing chronic disease and cognitive decline. In fact, initially healthy middle-aged adults in the Mediterranean region have found to have low incidence of fatal and non-fatal heart disease if they adhere closely to the Mediterranean diet.

In 2011, a systematic review found that a Mediterranean diet appeared to be more effective than a low-fat diet in achieving long-term changes to cardiovascular risk factors like lowering cholesterol level and blood pressure.

On April 17, 2013, a group of Spanish researchers reported in the ‘Journals of Gerontology Series A: Biological Sciences and Medical Sciences’ that adherence to a Mediterranean diet is associated with a lower risk of hyperuricemia.

Hyperuricemia is defined as a serum uric acid (SUA) concentration higher than 7 mg/dl in men and higher than 6 mg/dl in women. It is associated with metabolic syndrome, hypertension (high blood pressure), Type-2 diabetes mellitus, chronic kidney disease, gout and, cardiovascular morbidity and mortality. It is believed that the Mediterranean diet might help lower SUA concentration because of its antioxidant and anti-inflammatory properties.

7,447 male participants aged between 55 and 80 years old were examined in the 5-year study. These men were free from cardiovascular disease but had either Type-2 diabetes mellitus or were at risk of coronary heart disease. They were assigned to 1 of the 3 intervention diets: 2 were Mediterranean diets enriched with extra virgin olive oil or mixed nuts, and 1 was a control low-fat diet.

Only 4,449 participants were included in the analysis. Their concentrations of uric acid at baseline were available (of these, 1,551 were assigned to the Mediterranean diet plus olive oil group, 1,407 to the Mediterranean diet plus nut group, and 1,491 to the control low-fat diet group).

The findings of the study revealed positive health effects of a Mediterranean diet in older adults. The rates of reversion were higher among hyperuricemic participants at baseline who had greater adherence to the Mediterranean diets. Meanwhile, the researchers also found that the reversion of hyperuricemia was achieved by adherence to the Mediterranean Diet alone, without weight loss or changes to physical activity.