Health Benefits of Aspirin - Heart Attack and Stroke Benefits

Long-term aspirin = reduced risk of dying in women

Women who take low to moderate doses of aspirin have a reduced risk of death from any cause, and especially heart disease–related deaths, according to a report in the March 26, 2007 issue of Archives of Internal Medicine, one of the JAMA/Archives journals.

Some studies have provided evidence that aspirin may reduce the risk of heart disease and some types of cancer, the two leading causes of death in U.S. women, according to background information in the article. However, it is unclear whether aspirin reduces the risk of death overall for women.

Andrew T. Chan, M.D., M.P.H., Massachusetts General Hospital and Harvard Medical School, Boston, and colleagues examined the association between aspirin use and death in 79,439 women enrolled in the Nurses’ Health Study, a large group of female nurses who have been followed since 1976. Beginning in 1980 and again every two years through 2004, the women were asked if they used aspirin regularly and if so, how many tablets they typically took per week. At the beginning of the study, the women had no history of cardiovascular disease or cancer.

A total of 45,305 women did not use aspirin; 29,132 took low to moderate doses (one to 14 standard 325-milligram tablets of aspirin per week); and 5,002 took more than 14 tablets per week. By June 1, 2004, 9,477 of the women had died, 1,991 of heart disease and 4,469 of cancer. Women who reported using aspirin currently had a 25 percent lower risk of death from any cause than women who never used aspirin regularly.

The association was stronger for death from cardiovascular disease (women who used aspirin had a 38 percent lower risk) than for death from cancer (women who used aspirin had a 12 percent lower risk).

"Use of aspirin for one to five years was associated with significant reductions in cardiovascular mortality," the authors write. "In contrast, a significant reduction in risk of cancer deaths was not observed until after 10 years of aspirin use. The benefit associated with aspirin was confined to low and moderate doses and was significantly greater in older participants and those with more cardiac risk factors."

There are several mechanisms by which aspirin could reduce the risk of death, the authors note. "Aspirin therapy may influence cardiovascular disease and cancer through its effect on common pathogenic pathways such as inflammation, insulin resistance, oxidative stress [damage to the cells caused by oxygen exposure] and cyclooxygenase (COX) enzyme activity," also linked to inflammation, they write.

Because the study looked at women who made the decision themselves whether or not to take aspirin, as opposed to a clinical trial where women are randomly assigned to aspirin or a placebo, the results do not suggest that all women should take aspirin. "Nevertheless, these data support a need for continued investigation of the use of aspirin for chronic disease prevention," the authors conclude.

These findings differ from the results of other studies regarding the benefits of aspirin use in healthy women, leaving confusion about aspirin’s role, writes John A. Baron, M.D., Dartmouth Medical School, Lebanon, N.H., in an accompanying editorial.

Dr. Baron points out that in the Women’s Health Study, researchers followed almost 40,000 women for 11 years and did not find any reduced risk of cardiovascular or other death associated with aspirin therapy, in contrast to the dramatic risk reduction seen in the Nurses’ Health Study. "Is aspirin really that good or is there some other explanation for the findings that differ so much from those of the WHS and other primary prevention trials?" he writes.

"The difference between the NHS and the aggregated data from the WHS and other trials is too large to be explained by potential weaknesses in the randomized studies," Dr. Baron writes. "At the same time, one has to consider that the observational NHS may not have been able to deal with the differences between aspirin users and non-users."

"Therefore, these new findings by Chan et al cannot overcome the accumulated evidence that aspirin is not particularly effective for the primary prevention of death from cardiovascular disease in women," he concludes.

 

Bedtime aspirin may reduce risk of morning heart attack

Taking aspirin at bedtime instead of in the morning might reduce acute heart events, according a new study presented at the American Heart Association's Scientific Sessions 2013.

Low-dose daily aspirin is recommended for people at high risk of heart disease and for reducing the risk of recurrent heart events. Aspirin thins the blood and makes it less likely to clot. The tendency for platelet activity to be higher peaks in the morning.

The Aspirin in Reduction of Tension II trial is the first study to explore the timing of aspirin intake among cardiovascular disease patients. In the randomized, open-label study, 290 patients took either 100 mg of aspirin upon waking or at bedtime during two 3-month periods. At the end of each period, blood pressure and platelet activity was measured.

Blood pressure was not reduced; however, bedtime aspirin platelet activity was reduced by 22 units (aspirin reaction units).

"Because higher platelet activity contributes to a higher risk of acute heart events, this simple intervention – switching aspirin intake from morning to bedtime – could be beneficial for the millions of patients with heart disease who take aspirin on a daily basis," said Tobias Bonten, M.D., Ph.D student at the Leiden University Medical Center in the Netherlands.

Aspirin at night = significant reductions in blood pressure

Data unveiled at the American Society of Hypertension's Twenty Third Annual Scientific Meeting and Exposition (ASH 2008) revealed for the first time that people with prehypertension who are treated with aspirin may experience significant reductions in blood pressure—but only if they take the pill before bedtime, and not when they wake up in the morning.

People with prehypertension (a blood pressure reading between normal and high; when systolic blood pressure is between 120 and 139 or diastolic blood pressure is between 80 and 89 on multiple readings) are at significant risk of hypertension, or consistently high blood pressure—the biggest risk factor for heart disease and stroke, the two leading causes of death in the Western world.

“This is the first study to reveal that taking aspirin before bedtime as opposed to upon waking in the morning is an effective strategy to lower blood pressure and cost effective way to individualize treatment regimes in pre-hypertensive patients," said lead investigator Prof. Ramón C. Hermida, Director of Bioengineering and Chronobiology at the University of Vigo in Spain. "These findings therefore have vital treatment implications for these at-risk patients throughout the world.”

The purposeful timing of medications in order to enhance beneficial outcomes or to avert adverse effects is known as ‘chronotherapeutics’. Although factors influencing why aspirin has an impact on prehypertensive patients in the evening and not the morning are somewhat unclear, researchers indicate that it could be because aspirin slows down the production of hormones and other substances in the body that cause clotting. Many of those are produced while the body is at rest.

The study, which ran for three months, involved 244 participants (97 men and 138 women of 43.0±13.0 years of age) all of whom had all received diagnoses for prehypertension. Participants were divided into three groups: non pharmacological hygienic-dietary recommendations (HDR): HDR and a 100mg tablet of aspirin (ASA) on awakening or HDR and ASA at bedtime. Blood pressure levels were monitored at 20 minute intervals from 7:00 a.m. to 11:00 p.m. and at 30-min intervals at night for 48 consecutive hours at baseline and after three months of intervention. Physical activity was simultaneously monitored every minute by wrist (actigraphy) to accurately calculate sleeping and waking blood pressure on an individual basis.

The results showed that those who had taken aspirin before they went to bed (at an average time of 11:00 p.m.), decreased their systolic blood pressure by an average of 5.4 mmHg and their diastolic blood pressure by an average of 3.4 mmHg over the three-month study, without any change in heart rate of physical activity compared to baseline values (p<0 .001="" span="">

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“These results show us that we cannot underestimate the impact of the body's circadian rhythms," said Hermida. "The beneficial effects of time-dependent administration of aspirin have, until now, been largely unknown in people with prehypertension. Personalizing treatment according to one's own rhythms gives us a new option to optimize blood pressure control and reduce risk of cardiovascular disease down the line."

Why Don't More Women Take a Daily Aspirin to Prevent Heart Disease?

Heart disease is the leading cause of death among women, and evidence-based national guidelines promote the use of daily aspirin for women at increased risk for cardiovascular disease. However, less than half of the women who could benefit from aspirin are taking it, according to an article in Journal of Women’s Health, a peer-reviewed publication from Mary Ann Liebert, Inc.

“Based on this survey, it is evident that the majority of women for whom aspirin is recommended for prevention of cardiovascular disease are not following national guidelines,” says Editor-in-Chief Susan G. Kornstein, MD.

Among more than 200,000 women participating in a web-based survey to assess their risk for cardiovascular disease, only 41%-48% of women for whom aspirin is recommended reported that they took an aspirin daily, according to the study authors, Cathleen Rivera, MD and Texas-based colleagues from Scott and White Healthcare, Navigant Healthcare Consultants, and Texas A&M Health Science Center.

The women were more likely to use aspirin if they had a family history of cardiovascular disease or had high cholesterol, as reported in the article “Underuse of Aspirin for Primary and Secondary Prevention of Cardiovascular Disease Events in Women.” The authors conclude that improved educational programs are needed to increase awareness of the benefits of aspirin use to prevent heart disease among women.

Aspirin: High or Low Dose? No significant difference in preventing recurring cardiovascular events

Researchers report no significant difference in high versus low dose aspirin in preventing recurring cardiovascular events.

Each year, more than one million Americans suffer a heart attack and nearly all patients are prescribed a daily aspirin and an antiplatelet medication during recovery. However, the optimal aspirin dose has been unclear. Now, new research from Brigham and Women's Hospital (BWH) reports that there is no significant difference between high versus low dose aspirin in the prevention of recurring cardiovascular events in patients who suffer from acute coronary syndromes (ACS), which are characterized by symptoms related to obstruction in coronary arteries, which supply blood to the heart. These findings were presented at the American College of Cardiology Scientific Sessions on March 24, 2012.

"We observed no difference between patients taking a high dose versus a low of aspirin as it relates to cardiovascular death, heart attack, stroke or stent thrombosis," said Payal Kohli, MD,cardiology fellow at BWH and researcher in the TIMI Study Group, who is the lead author on this study. "Interestingly, we did find a dramatic difference in practice patterns of physicians in North America compared to those in the rest of the world," Kohli said. "North American physicians prescribed a high dose of aspirin for two-thirds of all their patients, while the exact reverse was true of the rest of the world. International physicians prescribed a low dose of aspirin to more than two-thirds of their patients." Dr. Stephen D. Wiviott, a cardiologist at BWH and researcher in the TIMI Study Group, is the senior author on the study.

Researchers analyzed data from more than 11000 patients from around the world that were enrolled in the TRITON-TIMI 38 trial, which randomized ACS patients to receive either clopidigrel or prasugrel, two different antiplatelet medications. Some patients were prescribed high doses of aspirin following a heart attack, while others, low doses. The aspirin dose was prescribed at the clinician investigator's discretion and the analysis included 7,106 patients who received low dose aspirin, defined as 150 mg or less, and 4,610 patients who received high dose aspirin, defined as 150 mg or more. Researchers reported that there was no significant difference observed in the prevention of the combination of heart attack, stroke, cardiovascular death or the prevention of stent thrombosis between the groups that received high or low dose aspirin.

Aspirin lowers trans fat-related stroke risk in older women

Older women whose diets include a substantial amount of trans fats are more likely than their counterparts to suffer an ischemic stroke, a new study shows.

However, the risk of stroke associated with trans fat intake was lower among women taking aspirin, according to the findings from University of North Carolina at Chapel Hill researchers.

The study, "Trans Fat Intake, Aspirin and Ischemic Stroke Among Postmenopausal Women," was published March 1, 2012 online in the journal Annals of Neurology.

The study of 87,025 generally healthy postmenopausal women aged 50 to 79 found that those whose diets contained the largest amounts of trans fats were 39 percent more likely to have an ischemic stroke (clots in vessels supplying blood to the brain) than women who ate the least amount of trans fat. The risk was even more pronounced among non-users of aspirin: those who ate the most trans fat were 66 percent more likely to have an ischemic stroke than females who ate the least trans fat.

However, among women who took aspirin over an extended period of time, researchers found no association between trans fat consumption and stroke risk – suggesting that regular aspirin use may counteract trans fat intake's adverse effect on stroke risk among women.

Trans fat is generally created in the food production process and is found in commercially prepared foods, including many shortenings, cake mixes, fried fast foods, commercially baked products (such as doughnuts, cakes and pies), chips, cookies and cereals.

Researchers from the UNC Gillings School of Global Public Health studied women who were enrolled in the Women's Health Initiative Observational Study. From 1994 to 2005, 1,049 new cases of ischemic stroke were documented.

Women who consumed the highest amount of trans fat also were more likely to be smokers, have diabetes, be physically inactive and have lower socioeconomic status than those who consumed the least trans fat, the study showed.

"Our findings were contrary to at least two other large studies of ischemic stroke," said Ka He, Sc.D., M.D., associate professor of nutrition and epidemiology at the UNC public health school. "However, ours was a larger study and included twice as many cases of ischemic stroke. Our unique study base of older women may have increased our ability to detect the association between trans fat intake and ischemic stroke among non-users of aspirin."

He said aspirin may lower the risk of ischemic stroke because of its anti-inflammatory and anti-platelet clumping properties.

The UNC researchers did not find any association between eating other kinds of fat (including saturated, monounsaturated or polyunsaturated fat) and ischemic strokes.

"Our findings highlight the importance of limiting the amount of dietary trans fat intake and using aspirin for primary ischemic stroke prevention among women, especially among postmenopausal women who have elevated risk of ischemic stroke," said lead author Sirin Yaemsiri, a doctoral student in the school's epidemiology department.

Higher daily dose of aspirin prevents heart attacks

In some cases, an apple a day may keep the doctor away, but for people with diabetes, regular, over-the-counter aspirin may also do the job.

A new study by University of Alberta researcher Scot Simpson has shed light on the use of aspirin as a preventive measure for cardiovascular disease and reoccurrence in patients with diabetes.

The study collected data from clinical trials that looked at whether taking aspirin as a course of treatment would prevent a first or recurrent heart attack or stroke.

Using information from diabetic patients in these studies, Simpson discovered that patients with previous cardiac episodes who were taking a low dose of aspirin daily had very little benefit in terms of prevention of a second heart attack or a decreased risk of mortality.

However, in patients taking higher doses of aspirin, the risk of a repeat heart attack and/or death was significantly lower.

"We took all of the data from 21 studies and focused specifically on diabetic patients who had suffered a previous heart attack or stroke to measure the ability of aspirin to prevent a second event. We found that, if those patients took up to 325 milligrams of aspirin per day, they had a 23 percent lower risk of death," said Simpson.

Simpson, an associate professor in the Faculty of Pharmacy and Pharmaceutical Sciences, says that people with diabetes are at an increased risk of cardiovascular disease, adding there is evidence that suggests as much as 60 per cent of deaths in diabetics are attributable to heart disease. Simpson says he always suspected the aspirin dosage could play a role in treating cardiovascular disease in diabetics and felt because aspirin was an over-the-counter medication, it's something that pharmacists could have an active role in administering.

"The pharmacists' best role for chronic disease management is working proactively with physicians and patients," said Simpson. "Whether that means working directly with the physician, and consulting about prescribed medications, or when the patient is deciding about whether or not to take aspirin as part of a treatment plan, pharmacists can have a significant, positive impact."

The benefits of aspirin treatment significantly outweigh the risk of a major hemorrhage

The American Heart Association:

“Background— Low-dose aspirin is an important therapeutic option in the secondary prevention of myocardial infarction (MI) and ischemic stroke, especially in light of its unique cost-effectiveness and widespread availability. In addition, based on the results of a number of large studies, aspirin is also widely used in the primary prevention of MI. This review provides an update of the available data to offer greater clarity regarding the risks of aspirin with respect to hemorrhagic stroke, as well as insights regarding patient selection to minimize the risk of this complication.

Summary of Review— In the secondary prevention of cardiovascular, cerebrovascular, and ischemic events, the evidence supports that the benefits of aspirin treatment significantly outweigh the risk of a major hemorrhage. The evidence from primary prevention of MI studies, including that from the recent Women’s Health Study evaluation of aspirin use in healthy women, demonstrate that the increased risk for hemorrhagic stroke is small, is comparable to the secondary prevention studies, and fails to achieve statistical significance. A reasonable estimate of the risk of hemorrhagic stroke associated with the use of aspirin in primary prevention patients is 0.2 events per 1000 patient-years, which is comparable to estimates of the risk associated with the use of aspirin in secondary prevention patients.

Conclusions— When considering whether aspirin is appropriate, the absolute therapeutic cardiovascular benefits of aspirin must be balanced with the possible risks associated with its use, with the most serious being hemorrhagic stroke.”

Another study had revealed that the 100 mg dose of aspirin every other day caused a 24 percent drop in the risk of ischemic stroke, which is the more common kind of stroke, and an insignificant increase in the risk of hemorrhagic stroke, hence the overall reduction in stroke risk of 17 percent.

Benefit of Aspirin in Cardiovascular Disease

On November 15, 2009, Florida Atlantic University (FAU) researcher Charles H. Hennekens, M.D., presented at the American Heart Association's Annual Scientific Sessions meeting in Orlando, FL, the first data in humans to show that all doses of aspirin used in clinical practice increase nitric oxide. Nitric oxide is released from the blood vessel wall and may decrease the development and progression of plaques leading to heart attacks and strokes.

The abstract, titled "Usual Doses of Aspirin Increase Nitric Acid Formation in Humans" is published in the November 2009 issue of Circulation, the official journal of the American Heart Association.

FAU researchers conducted a randomized trial in patients at high risk of a first heart attack or stroke and assigned them to different doses of aspirin for 12 weeks. All doses produced highly significant beneficial effects on two important and well documented markers of nitric oxide formation.

"While the ability of aspirin to decrease the clumping of blood platelets is sufficient to explain why the drug decreases heart attacks and strokes, these data suggest a new and novel mechanism," said Hennekens.

Co-author and project director of the trial and affiliate clinical instructor of clinical science and medical education, Wendy Schneider, MSN, RN, said, "We are proposing new and longer term research to test whether this hypothesis has clinical or public health relevance."

The American Heart Association recommends aspirin use for patients who've had a myocardial infarction (heart attack), unstable angina, ischemic stroke (caused by blood clot) or transient ischemic attacks (TIAs or "little strokes"), if not contraindicated. This recommendation is based on sound evidence from clinical trials showing that aspirin helps prevent the recurrence of such events as heart attack, hospitalization for recurrent angina, second strokes, etc. (secondary prevention). Studies show aspirin also helps prevent these events from occurring in people at high risk (primary prevention).

Aspirin Improves Survival in Women with Stable Heart Disease

New results from the Women’s Health Initiative (WHI) Observational Study provide additional evidence that aspirin may reduce the risk of death in postmenopausal women who have heart disease or who have had a stroke.

The study also provides new insight into aspirin dosing for women, suggesting that a lower dose of aspirin (81 milligrams, or mg) is as effective as a higher dose (325 mg). This is good news for women who might be concerned with internal bleeding, a well-known risk of aspirin that may be more likely with higher doses of aspirin, according to other studies. However, randomized clinical trials are needed to determine the optimal doses of aspirin in women with cardiovascular disease.

“Aspirin Use, Dose, and Clinical Outcomes in Postmenopausal Women with Stable Cardiovascular Disease – The Women’s Health Initiative Observational Study,” appears in the March issue of the journal Circulation: Cardiovascular Quality and Outcomes and was published online March 5, 2009.

Scientific evidence indicates that, in general, aspirin lowers the risk of death and incidence of heart attack and stroke in patients with a history of cardiovascular disease; however, the benefits of aspirin in women with stable cardiovascular disease in particular are unknown. In this study, researchers analyzed data from 8,928 postmenopausal women who had previously had a heart attack, stroke or transient ischemic attack (TIA, or mini-stroke), angina, or angioplasty or coronary bypass surgery to improve blood flow. Participants were followed for an average of 6.5 years.

Compared to those who did not report taking aspirin, regular aspirin users had a 25 percent lower risk of death from cardiovascular disease and a 14 percent lower risk of death from any cause. Overall, aspirin use did not significantly decrease the risk of heart attack, stroke, or other cardiovascular events, except among women in their seventies. There were no significant differences in death rates or other outcomes between women taking 81 mg of aspirin compared to those taking 325 mg.

The size of the WHI Observational Study and the diversity of participants provide valuable insight into the use of medications in the primary care setting. For example, the study found that only 46 percent of women with stable cardiovascular disease in the study reported taking aspirin regularly, despite current guidelines recommendations. In addition, subgroup analyses indicate that black women and women with Medicaid insurance were less likely to use aspirin as recommended, compared to women of other ethnic groups and insurance status.

The WHI is a major, 15-year research program designed to address the most frequent causes of death, disability, and poor quality of life in postmenopausal women: cardiovascular disease, cancer, and osteoporosis. The WHI Observational Study is a nationwide, prospective study to examine the association between clinical, socioeconomic, behavioral, and dietary risk factors and the subsequent incidence of several health outcomes. The Observational Study followed 93,676 postmenopausal women between the ages of 50 and 79 for an average of 8 years. Participants filled out health forms and visited their clinic physician periodically; participants were not required to take any medication or change their health habits.

 

Aspirin Better Heart Treatment for Men than Women

A new study shows that aspirin therapy for coronary artery disease is four times more likely to be ineffective in women compared to men with the same medical history.

Historically, studies have shown that aspirin therapy is less effective in women than in men, but it has remained unclear how much less effective and whether this affects patient outcomes, said Michael Dorsch, clinical pharmacist and adjunct clinical instructor at the University of Michigan College of Pharmacy.

Dorsch is the lead author of the paper, "Aspirin Resistance in Patients with Stable Coronary Artery Disease," which appears online tin the Annals of Pharmacotherapy.

Originally, Dorsch and his team set out to determine if patients with a history of heart attacks were more apt to be aspirin resistant than those with coronary artery disease but no history of heart attack. They found that gender and not medical history was a predictor for aspirin resistance, Dorsch said. The results surprised him.

"I was surprised by how big of a difference it was for females," said Dorsch, who has appointments at the U-M Health System and the U-M College of Pharmacy, and started the study as a resident at the University of North Carolina. "This is another piece of information that affirms we need more studies in women."

Aspirin therapy is a cornerstone in managing heart disease because it inhibits blood clotting. Aspirin therapy can reduce the risk of a nonfatal heart attack or stroke by about 23 percent, and an estimated 20 million men and women take a low dose of aspirin (81-325 mg daily) to control heart disease. But despite its effectiveness, there is evidence that aspirin is less effective in some patients, and researchers don't really know why. This can be frightening because most doctors do not check for aspirin resistance before prescribing aspirin therapy and therefore presume it's working in the patient when it may not be, he said.

There isn't enough evidence to show if people who are aspirin resistant can simply take larger doses, but Dorsch warns that people taking aspirin on the advice of a doctor shouldn't stop therapy on account of these results.

Not only did the study quantify how much more effective aspirin therapy is for men than for women, it is also the first study that Dorsch knows of to measure aspirin resistance in men and women with stable coronary artery disease. Previous studies have looked at the impact of aspirin therapy on people who have had a heart attack.

For the study, researchers randomly selected 100 patients who were visiting their cardiologist for a regularly scheduled appointment. All had coronary artery disease but only half had a history of heart attack.

Researchers used a device called VerifyNow Aspirin Assay to test the percentage of platelet reactivity after blood samples were exposed to a chemical that causes clotting.

Aspirin works by causing platelet inhibition in the blood, which means that platelets cannot stick together and this slows the formation of blood clots that cause a heart attack or stroke.

"This does happen in women, but it doesn't happen in as many women and it's not as effective," Dorsch said. The testing device uses an optical sensor to "see" what percentage of the platelets in the blood sample clump together. Anything less than 40 percent platelet inhibition is considered aspirin resistant.

"We really don't know the mechanism," Dorsch said. "It could be that women have a more active platelet system in the body so it's less likely that platelet action would be inhibited."

In the future, researchers hope to look at aspirin therapy outcomes in women only and see if those outcomes can be changed. The majority of testing for aspirin therapy has been on men, so not much is known about how women respond.

"Heart disease is the number one killer of women in the United States. Future research should be aimed at finding out the cause of this increase in aspirin resistance and the effect on outcomes in women with heart disease." Dorsch said.

Aspirin saves lives of cancer patients suffering heart attacks, despite fears of bleeding

Many cancer patients who have heart attacks often are not treated with life saving aspirin given the belief in the medical community that they could experience lethal bleeding. Researchers at The University of Texas M. D. Anderson Cancer Center, however, say that notion is now proven wrong and that without aspirin, the majority of these patients will die.

Researchers say that their study, to be published in the February 1, 2007 issue of the journal Cancer and now available online, turns common medical assumptions upside down and will likely change medical practice for cancer patients. Because aspirin can thin blood and cancer patients experience low platelet counts and abnormal clotting, physicians view aspirin as a relative contraindication. Given that blood platelets are responsible for the clotting process, physicians do not eagerly prescribe aspirin as a standard treatment.

In this study, however, the investigators found that 9 of 10 cancer patients with thrombocytopenia (low platelet count) who were experiencing a heart attack and who did not receive aspirin died, whereas only one patient died in a group of 17 similar cancer patients who received aspirin. They also found aspirin helps cancer patients with normal platelet count survive heart attacks, just as it does for people without cancer.

"The notion that heart attacks in patients with low platelets should be treated with clot-dissolving aspirin defies logic, that is unless you suspect that the cancer is interfering with platelet function," says the study's senior investigator and author, Jean-Bernard Durand, M.D., assistant professor in the Department of Cardiology at M. D. Anderson Cancer Center.

"We believe tumors may be releasing chemicals that allow the cancer to form new blood supplies which makes blood more susceptible to forming clots." Durand, a heart failure specialist, says. "There appears to be a platelet paradox suggesting that cancer may affect the mechanism of the way that blood clots, and from this analysis, we have found that the single most important predictor of survival in these patients is whether or not they received aspirin." Durand says more research is needed to better understand this contraindication.

According to the World Health Organization there are approximately 10 million cancer patients worldwide, of which 1.5 million may develop blood clots during their cancer treatment and, as such, are at a much higher risk of dying from heart disease if not treated properly. "Now that we have this study, it would be a travesty if you survive treatment for cancer only to die of a heart attack soon thereafter," Durand says.

According to Durand, no guidelines currently exist for treatment of heart attacks in patients with cancer. He says that physicians are especially perplexed about what to do for cancer patients with thrombosis (blood clots), a condition that affects about 15 percent of all cancer patients and can be due to the use of chemotherapy or the presence of cancer.

Durand came to M. D. Anderson in 2000 to start the Cardiomyopathy Services, which is believed to be the only program in the world specifically designed to look at cardiovascular complications caused by chemotherapy treatment. He is also the co-founder of CONQUER (Cardiology Oncology International Quest to Educate and Research Heart Failure in Cancer), a newly created organization with goals of increasing the success of chemotherapy by reducing cardiovascular disease as a barrier and long term risk.

He and anesthesiologist Mona Sarkiss, M.D., Ph.D., made the observation that patients with thrombocytopenia who suffered a heart attack and were being treated in the intensive care unit at M. D. Anderson tended to die more often when they were not given aspirin. However, they noted that some of the patients given aspirin and/or beta-blockers had "great" clinical outcomes. "Because no practice guidelines exist, physicians were treating their patients with great variability and the disparity was obvious," Durand says.

Sarkiss, who is the study's lead author, Durand, and a team of researchers conducted a retrospective analysis of cancer patients treated for heart attacks at M. D. Anderson Cancer Center in 2001. These 70 patients were divided into two groups based on their platelet counts, and data was collected on the use of aspirin, bleeding complications, and survival.

They found that heart attack patients with low platelets who did not receive aspirin had a seven-day survival rate of 6 percent, compared with 90 percent survival in those who received aspirin. Dr. Durand notes that there were no severe bleeding complications in patients who used aspirin.  Conversely, patients with low platelet counts who formed a blood clot and were not exposed to aspirin died.

The beneficial effect of aspirin also was seen in patients with normal platelet counts. Seven-day survival was 88 percent in aspirin-treated patients as compared to 45 percent in patients who did not receive aspirin, the researchers found.

Durand observed that these deaths rates are abnormally high. "In the non-cancer patient with acute coronary syndrome anywhere in the United States, an expected seven-day mortality is less than 1 percent," he says.

There were parallel findings for those patients in either group who were treated with beta-blockers, which block the heart's use of adrenalin. The protective effect was not as strong as seen with aspirin, but was still life saving.

In those patients with a normal platelet count, 91 percent survived seven days when treated with beta-blockers, whereas 36 percent survived if they were not treated with the agent. In the thrombocytopenic group, 73 percent survived seven days when treated with beta-blockers, whereas only 13 percent survived if they were not treated.

Aspirin cuts risk of clots, DVT by a third -- new study

Low dose aspirin lowers the occurrence of new venous blood clots – and represents a reasonable treatment option for patients who are not candidates for long-term anticoagulant drugs, such as warfarin, according to a new study published in the August 25, 2014  issue of Circulation.

"The study provides clear, consistent evidence that low-dose aspirin can help to prevent new venous blood clots and other cardiovascular events among people who are at risk because they have already suffered a blood clot," says the study's lead author, University of Sydney Professor, John Simes.

"The treatment effect of aspirin is less than can be achieved with warfarin or other new generation direct thrombin inhibitors, which can achieve more than an 80 per cent reduction in adverse circulatory and cardiopulmonary events.

"However, aspirin represents a useful treatment option for patients who are not candidates for anticoagulant drugs because of the expense or the increased risk of bleeding associated with anticoagulants."

Key results

Compared to placebo patients, those who took 100mg daily of aspirin had a one-third reduction in the risk of:

•    thromboembolism, which is the obstruction of a blood vessel by a clot that has dislodged from another site in the circulation.

•    deep vein thrombosis (DVT), which is the formation of a blood clot in a deep vein, predominantly in the legs.

•    pulmonary embolism, which is a blood clot affecting the arteries that supply blood to the lungs.

•    myocardial infarction (heart attack), stroke or cardiovascular death.

Most people who have had a blood clot in a leg vein (deep-vein thrombosis) or an embolism (where the clot blocks the blood flow) have anticoagulant drug treatment (such as warfarin) for at least 6 months, first to dissolve the clot and then to prevent it happening again.

However, long-term anticoagulant drugs are expensive and inconvenient, requiring frequent regular blood tests and adjustments to the dosage. Further, there is an elevated risk that the treatment could cause bleeding in some patients. For people who are not able to cope with this, the viable alternative of taking regular aspirin will be a great benefit.

"The study provides evidence that after a first venous thrombosis or embolism, daily aspirin reduces the risk of another event, without causing undue bleeding. This treatment is an alternative to long-term anticoagulation and will be especially useful for patients who do not want the inconvenience of close medical monitoring or the risk of bleeding," says Professor Simes.

"Aspirin will be ideal in the many countries where prolonged anticoagulant treatment is too expensive. A major benefit of this treatment is its cost-effectiveness. Aspirin is cheap, but it will save the treatment costs of the many recurrent clots that are prevented. This could mean a saving of millions of healthcare dollars worldwide."

Co-investigator Tim Brighton, a senior haematologist at Sydney's Prince of Wales Hospital, adds: "This important study demonstrates clearly that low-dose aspirin reduces the risks of further blood clot. This is especially important for patients who are not able to take long-term anticoagulant medications for whatever reason, such as personal preference, adverse effects of anticoagulant or cost."

Baby aspirin? Many doctors don't recommend, despite guidelines     

A majority of middle-aged men and women eligible to take aspirin to prevent heart attack and stroke do not recall their doctors ever telling them to do so, according to a University of Rochester study of a national sample of more than 3,000 patients.     

Published online by the Journal of General Internal Medicine, the finding illustrates a common disconnect between public health guidelines and what occurs in clinical practice. The UR study is consistent with other research showing that physicians often do not recommend aspirin as prevention therapy to the general population, despite established guidelines by the U.S. Preventative Services Task Force.  Several reasons might explain the reluctance, such as competing demands and limited time to properly assess a patient's eligibility for aspirin, according to lead author Kevin A. Fiscella, M.D., M.P.H., professor of Family Medicine at the UR School of Medicine and Dentistry.  Uncertainty about the benefits of aspirin therapy versus potential harms like bleeding in the digestive track, also hinder physicians' decisions, the study said.  

For the JGIM study, Fiscella's group analyzed data from 3,439 patients included in the 2011-'12 National Health and Nutrition Examination Survey (NHANES). None of the patients had cardiovascular disease, but all qualified for aspirin therapy based on their 10-year risk score for factors such as diabetes, high blood pressure, obesity, smoking, and use of cholesterol-lowering medications.  Of the sample, 87 percent of men and 16 percent of women were eligible to take aspirin as a preventive measure. But when they were asked the question -- "Doctors and other health care providers sometimes recommend that you take a low-dose aspirin each day to prevent heart attack, strokes, or cancer. Have you ever been told to do this?" -- a low rate of 34 percent of the men and 42 percent of the women said yes.  

Co-author John Bisognano, M.D., Ph.D., director of outpatient cardiology services at UR Medicine, said most physicians can agree on approaches to medical care in immediately life-threatening situations, but have less enthusiasm to quickly embrace preventive guidelines, particularly when they involve wide-ranging interventions for a large segment of the population.  New studies that present conflicting data or re-interpret older data also complicate the issue and can be confusing for patients, he said. Despite the USPSTF guidelines for aspirin being published in 2009, for example, the FDA declined to approve the same recommendations as recently as last spring.  

"Patients often view changes as an illustration that folks in the medical field can't really make up their minds," said Bisognano, professor of Medicine. "Changes can undermine a practitioner's or patient's enthusiasm to immediately endorse new guidelines because they wonder if it will change again in three years."  But science and medical practice is fluid, he said, and the only way to move the field forward is to continually understand and look for ways to apply the new data and avoid assumptions of the past.  

The study also noted that using expanded primary care teams of nurses, medical assistants, and health educators may help to reduce the volume of decisions that rest solely with the physician at the office visit. Sharing care can improve agreement between published guidelines, the use of risk models, and actual practice, the study said.