Although patients with acute coronary syndrome (ACS) share key pathophysiological mechanisms, they present with diverse clinical, electrocardiographic and enzyme characteristics and experience a wide range of serious cardiovascular outcomes.
Continue reading The use of risk scores for stratification of acute coronary syndrome patients
Fat around the heart— known as pericardial fat— may be a better predictor of future heart disease than either body mass index (BMI) or waist circumference, a new study suggests.
The study, published in the September issue of the American Journal of Clinical Nutrition (Am J Clin Nutr 2009;90:499-504), was conducted by US researchers led by Dr Jingzhong Ding (Wake Forest University School of Medicine, Winston-Salem, North Carolina, US).
They conducted a case-cohort study in 998 individuals taking part in the Multi-Ethnic Study of Atherosclerosis (MESA), who had no history of cardiovascular disease. The volume of pericardial fat was measured using cardiac CT scans performed at baseline in the MESA trial.
Of the 998 individuals, 26 developed coronary heart disease during the five year follow-up. In unadjusted analyses, pericardial fat, but not body mass index, was associated with the risk of coronary heart disease (CHD). Waist circumference was marginally associated with CHD risk. The relation between pericardial fat and CHD remained significant after further adjustment for body mass index and other cardiovascular disease risk factors.
“Our data support the idea that pericardial fat is a better predictor of incident CHD than are more general measures of adiposity (e.g. BMI or waist circumference),” the authors say. However, they note that routine CT scans are not feasible for mass screenings at the present time, but the echocardiographic measurement of pericardial fat “has potential for CHD risk stratification”.
The Framingham and UKPDS (United Kingdom Prospective Diabetes Study) risk equations overestimate the probability of cardiovascular events in people with type 2 diabetes, according to several studies presented at the International Diabetes Federation 2009 meeting held in October in Montreal, Canada.
In one study, a group led by Dr Andre Pascal Kengne (University of Sydney, Australia), noted that data from the recent ADVANCE (Action in Diabetes and Vascular Disease) trial conducted in more than 7,000 patients with diabetes worldwide, suggested that the UKPDS equation overestimated risk of major coronary heart disease (CHD) by 198%, and the two Framingham equations overestimated the risk by 146% and 289%. A group from Greece led by Dr Athanasios Kofinis (National University of Athens) reported similar findings from a five-year study of more than 900 people with diabetes.
A new stethoscope – the Littmann 3200 – is now available which is the first to enable Bluetooth transfer of sounds to software for storage and further analysis.
Complementary software has been developed which allows the visualisation, manipulation and slowing down of auscultated sounds to allow focus on particular areas of interest. Being able to store recordings electronically enables comparison with future auscultations and also allows them to be sent easily for second opinion.
The new stethoscope, which has been developed by 3M, comes with its patented ambient noise reduction technology, which cancels out an average 85% of distracting backgkround noise. The StethAssist software has been developed by Zargis Medical Corp.
Conventional cooling methods can improve survival and reduce neurologic injury after cardiac arrest, a new Cochrane Review reports.
Conventional cooling methods can improve survival and reduce neurologic injury after cardiac arrest, a new Cochrane Review reports.
In the review, Dr Jasmin Arrich (Medical University of Vienna, Austria) and colleagues explain that although therapeutic hypothermia is recommended in many resuscitation guidelines, it is still a relatively new therapy.
The current review included 1,092 randomised trials of therapeutic hypothermia in adults within six hours of cardiac arrest. Five trials that included adequate data on neurological outcomes, including three that provided individual patient data, were included in a systematic meta-analysis.
In these trials, patients treated with conventional cooling methods were more likely to return to good cerebral performance or suffer only moderate cerebral disability during their hospital stay compared with patients treated with standard resuscitation care (relative risk 1.55).
Several different cooling methods were used in the studies including cooling packs placed around the patient’s head, neck, and torso, a cooling blanket plus cold air, a cooling helmet containing aqueous glycerol, and high-flow haemofiltration with or without direct external cooling of the blood.
A new drug, lorcaserin, showed good weight loss results without the valvular side-effects associated with some other serotonin type agents in the Phase III Blossom (Behavioural Modification and Lorcaserin Second Study for Obesity Management) study, presented at the Obesity 2009 meeting held in October in Washington DC, USA.
Lorcaserin acts as an agonist at the 5HT2C-receptor. Lead investigator of the Blossom study, Dr Lee Kaplan (Massachusetts General Hospital, Boston, USA) explained that serotonin is known to be important in inducing weight loss; previous drugs have raised endogenous serotonin levels. More has been discovered about various different serotonin receptors, and it is now thought that the 5HT2B receptor is responsible for the cardiac valvular effects of these serotonergic drugs, while the 5HT2C receptor is responsible for weight loss. So by stimulating the 5HT2C receptor alone, it should be possible to induce weight loss without the valvular side effects.
In the BLOSSOM trial, 3,182 obese and overweight patients were randomised to treatment with lorcaserin 10 mg twice daily, 10 mg once daily, or placebo. After one year, the intention-to-treat analysis showed weight reductions of 5.8 kg in the lorcaserin twice daily group, 4.7 kg in the lorcaserin once daily group and 2.9 kg in the placebo group. When looking at only those patients who completed the study (about 60% of patients), weight reductions were larger —7.7 kg (lorcaserin twice daily), 6.5 kg (lorcaserin once daily), and 3.9 kg (placebo).
In the intention-to-treat analysis, 47.2% of patients in the lorcaserin twice daily group, lost more than 5% of their body weight, compared with 40.2% receiving lorcaserin once daily, and 25% of those on placebo. And weight reductions greater than 10% were achieved by 22.6% of the twice daily group and 17.4% of the once daily group.
The most common adverse events with lorcaserin were headache, nausea, dizziness, fatigue, and dry mouth. Approximately 100 patients reported a serious adverse event in the trial, but the difference between lorcaserin and placebo was not significant. Six events (including syncope, depression, and anxiety) were considered to be possibly related to the study drug.
The trial included 56 patients with pre-existing echocardiographic valvulopathy and there was no worsening of valve disease in these patients. Rates of new valve problems were similar in all three arms.
N-terminal pro-B-type natriuretic peptide (NT-proBNP) is a “remarkable predictor” of incident atrial fibrillation (AF), even after adjustment for other known risk factors, according to the results of a new study.
Reporting their findings (Circulation 2009;120:1768-74), a team led by Dr Kristen Patton (University of Washington, Seattle, US) conclude that: “Our results indicate a compelling, graded association between NT-proBNP levels and AF in a large, diverse cohort with extensive follow-up. The fact that elevated baseline NT-proBNP levels predict a diagnosis of AF even 16 years later suggests that peptide elevations precede the onset of arrhythmia,” they add.
BNP, a neurohormone produced by the heart, regulates cardiac function and is widely used as a marker of heart failure. The precursor protein pro-B-type natriuretic peptide is cleaved to form BNP and the amino terminal NT-proBNP; both of these circulate in the plasma.
A previous study using Framingham data has also shown elevated BNP levels to be predictive of AF but only 68 subjects developed AF during the study. The current study, however, analysed data from 5,445 men and women over 65 years of age participating in the Cardiovascular Health Study, in which there were 1,126 cases of incident AF. Among those with the highest levels of NT-proBNP, there was a four-fold increase in the risk of incident AF compared with individuals with the lowest levels.
In the current study, NT-proBNP remained the strongest predictor of incident AF after adjustment for other variables, including age, sex, medication use, blood pressure, echocardiographic variables, diabetes mellitus, and heart failure.
The authors note that little is known about the potential electrophysiological effects of BNP, but they speculate that it may have similar properties to atrial natriuretic peptide which has been shown to affect the sodium, calcium and potassium channels and increase the cardiac pacemaker current.
New analyses of data from ECASS 3 (Third European Cooperative Acute Stroke Study) suggest that the thrombolytic, tPA (alteplase) has benefits in the treatment of stroke up to 4.5 hours after symptom onset. This builds on the current approved time window of three hours.
This new report from ECASS 3 was published online on October 21st in Lancet Neurology. The authors, led by Dr Werner Hacke (Ruprecht-Karls-Universität, Germany) report that although not all end points were statistically significant, there was “a clear pattern in favour of alteplase”.
In the ECASS 3 trial, 821 stroke patients presenting 3-4.5 hours after symptom onset were randomised to alteplase (in the approved regimen of 0.9 mg/kg body weight) or placebo.
The primary end point was disability at 90 days, and this was judged by a favourable or unfavourable outcome on the modified Rankin Scale. Results showed that significantly more patients treated with tPA had a favourable outcome (52.4%) by this measure than those who received placebo (45.2%), giving an odds ratio of 1.34 (p=0.04).
A secondary end point, a combination of four neurologic and disability scores, also showed an improvement with the thrombolytic therapy (odds ratio 1.28; p<0.05). These beneficial effects of alteplase were evident regardless of patient age and the severity of stroke.
There was an increase in intracerebral haemorrhage with alteplase but this was not associated with an increase in mortality. The incidence of symptomatic intracranial haemorrhage appeared to be independent of previous antiplatelet drug use, and time from onset of symptoms to treatment, but was influenced by age, with a much higher incidence in patients aged over 65 years (odds ratio versus placebo 5.79) than those under 65 years (odds ratio versus placebo 0.74).
“Even with these encouraging findings, the most important principle of acute stroke intervention should, however, not be lost—i.e. time remains critical, and fast treatment still provides the greatest chance of recovery,” the authors conclude.
Extending clopidogrel treatment from one to two years after drug-eluting stent placement is associated with a reduction in very late thromboses, new registry data suggest.
These results, from the TYCOON (Two-Year Clopidogrel Need) registry, were published online on September 28, 2009 in the American Journal of Cardiology.
Current guidelines recommend at least 9-12 months of dual antiplatelet therapy (aspirin plus clopidogrel) following intervention with a drug-eluting stent to prevent thromboses, but authors of the TYCOON paper, wanted to investigate whether longer treatment would be better.
The TYCOON database includes 897 consecutive patients who received a coronary stent in 2003 and 2004, about half of whom received a drug-eluting stent. Patients given a drug-eluting stent in 2003 were treated with clopidogrel for 12 months, whereas those given a drug-eluting stent in 2004 continued on clopidogrel for two years.
Results showed that there were four very late thromboses in the 173 drug-eluting stent patients who stopped clopidogrel after one year, but none in those who stayed on the drug for a further year. A drug detox is a must to start a healthy life.
The authors note that these results appear to conflict with other studies showing no difference in stent thrombosis in patients stopping or continuing clopidogrel after one year. They suggest that all the studies so far conducted are too small to show definitive results as very late stent thrombosis is such a rare event.
A randomised trial – the Dual Antiplatelet Therapy (DAPT) Study – is underway to answer this question. This study is comparing 12 and 30 months of dual antiplatelet therapy and is powered to show differences in rates of stent thrombosis and major adverse cardiovascular and cerebrovascular events.
The use of niacin was associated with a regression of atherosclerotic plaque in a new imaging study.
The recently published study (J Am Coll Cardiol 2009;54:1787-94), was conducted by a group led by Dr Justin Lee (University of Oxford).
In the study, 71 patients with low high-density lipoprotein (HDL) cholesterol and vascular disease were randomised to modified release nicotinic acid (uptitrated to 2 g daily), or placebo. All patients were already taking statins. Magnetic resonance imaging (MRI) was performed at baseline and at six and 12 months, with blood samples taken at the time of MRI.
Results showed that the primary end point of absolute change in carotid artery wall area at one year was reduced by 1.64 mm2 in the niacin group compared to the placebo group, a statistically significant difference. However, there were no significant differences between the two groups in aortic wall area and other measures of vascular function by MRI. Niacin also increased HDL by 23% and decreased low-density lipoprotein (LDL) cholesterol by 19%.
Niacin use has been limited by side effects and these were again problematic in this study, with 20% of the niacin group withdrawing because of drug-related side effects (flushing, itching, and gastrointestinal upset) or MRI claustrophobia.
The researchers conclude: “Our study shows, for the first time, that in patients with low HDL-C and existing atherosclerotic disease, addition of nicotinic acid 2 g daily to contemporary therapy reduces atherosclerosis compared with placebo. The findings support current recommendations for the use of nicotinic acid and strongly underpin the rationale for the large clinical outcome studies that are ongoing”.
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