heart

Arterial Disease


Heart Attacks



Strokes

Some Topics

medical
  • Anti-platelet therapy

    The use of drugs in cardiovascular medicine is like fashion - always changing. The use of Acetylsalicylic Acid (ASA or Aspirin) taken in a small dose daily, has been advocated for many years to reduce the risk heart attacks and strokes. ASA is a platelet inhibitory drug, effective in doses as low as 50 mg per day. The growing list of contradictory studies is more evidence of drug companies determined to control the marketplace, rather than good science and is clearly not good public policy. Buyer beware. To create markets for more expensive, prescription platelet inhibitors, inexpensive, over the counter ASA must be discredited. A similar battle for market share is occurring with hydrochlorothiazide and inexpensive diuretic that is widely prescribed as the first drug of choice to lower blood pressure.

    What is the best self management policy? You might agree that ASA has benefits in the primary and secondary prevention of heart attacks in men with less benefit in women younger than 55. Aspirin has a benefit in women over the age of 65 in the prevention of stroke. All people who have a transient cerebral ischemic attack should start ASA prevention therapy. ASA should be taken by people who have had a heart attack or a stroke.

    Background

    One major shift in recommendations was based on noticing differences among men and women of different ages. Ridket and Beller pointed out that 95,000 men and women participated in aspirin prevention trials with a net 24% reduction in myocardial infarction and no benefit on stroke; however if you stratify men and women separately, you get 44,000 men with 32% reduction in heart attack. In contrast the 51,000 women had little or no reductions in myocardial infarction, but a significant 19% reduction in the risk of stroke.

    A further study looked at the experience of women over the age of 45 more closely. A total of 39,876 women participated in the trial to receive aspirin 100 mg very other day or placebo. The mean follow-up period was 10.1 years. The primary endpoint was first major cardiovascular event, which included nonfatal MI, nonfatal stroke, or cardiovascular death. Secondary endpoints were the individual endpoints of fatal or nonfatal MI, fatal or nonfatal stroke, ischemic stroke, hemorrhagic stroke, and death from cardiovascular causes. Additional analyses included the incidence of death from any cause, transient ischemic attack (TIA), and the need for coronary revascularization.

    The characteristics for the groups were similar; participants were 54.6 years of age and more than half were postmenopausal; slightly more than one-quarter were hypertensive and nearly 85% had a 10-year Framingham risk score < 5%. Ridket stated: “Women over the age of 65, have a benefit of stroke reduction associated with low-dose aspirin. In women under age 65, my feelings are go to the gym, lose weight, eat a healthy diet, and maybe the benefit of aspirin is just smaller than we had hoped.”

    ASA inhibits the cyclo-oxygenase enzyme in platelets leading to reduced formation of prostaglandin G2, the precursor of thromboxanes. Two hours after oral administration, ASA inhibits blood thromboxane A2 generation and arachidonic acid (AA)-induced platelet aggregation . The ASA effect on circulating platelets is long-lasting, so that small daily doses sustain the effect. ASA has limitations. ASA blocks the synthesis of thromboxane A, but has no effect on thromboxane-independent mediators of platelet activation, such as adenosine diphosphate, thrombin and serotonin. Up to 30% of people with coronary artery disease are unresponsive to ASA, when the inhibition of platelet activation and aggregation and bleeding time is measured.

    • The caveat here is the enteric coated ASA is less effective than plain ASA and that higher doses are less effective than lower doses.

    • The easiest and least expensive preparation to take is plain ASA, children's size, not enteric coated.

    • The popular anti-inflammatory drug, Ibuprofen, inhibits the antiplatelet effect of ASA. ASA should be taken one hour before taking ibuprofen or 8 hours after taking ibuprofen to preserve the antiplatelet activity of ASA.

      ASA and Diabetes Confusing Studies

      A major contradiction to standard medical advice appeared in 2008 with results of the Prevention of Progression of Arterial Disease and Diabetes Trial that involved 1,276 people with type 1 or type 2 diabetes who had no symptoms of coronary heart disease. Participants were randomly assigned to receive either a daily 100 mg aspirin tablet plus antioxidant capsule, an aspirin tablet plus placebo capsule, a placebo tablet plus antioxidant capsule (n=320), or a placebo tablet plus placebo capsule. Results showed that aspirin – taken alone or in combination with an antioxidant capsule – did not significantly reduce the risk of death from coronary heart disease or stroke, or non-fatal myocardial infarction or stroke. In his review of this study Hiatt suggested that these findings, together with those of 6 other trials, suggest that international guidelines and the prescribing practice of doctors should be reviewed so that aspirin is only prescribed to patients with established cardiovascular disease. [i]

      This pessimistic advice was revised by the USPSTF recommendations on the use of aspirin for primary prevention of heart disease, published in the March 2009, issue of the Annals of Internal Medicine. They stated that men aged 45 to 79 years and women aged 55 to 79 years should use aspirin when the potential benefit of a reduction in heart attacks and strokes outweighs the potential harm of an increase in gastrointestinal hemorrhage. They favored a dose of 75 mg/day.[ii] Sung et al demonstrated that even when GI hemorrhage occurs, continuing ASA reduces all-cause mortality and does not increase the risk of rebleeding. The did a detailed study of 156 patients admitted with an upper GI bleed while taking ASA as secondary prophylaxis for cardiovascular and neurologic indications.[iii]

      Other Platelet Inhibitors

      Clopidogrel is recommended if the patient is ASA-intolerant. Sabatine et al found that patients in the process of myocardial infarction with ST-segment elevation who received aspirin and a standard fibrinolytic regimen benefited from the addition of clopidogrel (300-mg loading dose, followed by 75 mg once daily). The combination of drugs improved the patency rate of the infarct-related artery and reduced ischemic complications. [iv] After doing a study of 15,603 patients, Bhatt et al reported that clopidogrel plus aspirin was not more effective than aspirin alone in reducing the rate of myocardial infarction, stroke, or death from cardiovascular causes. [v] In patients with aspirin-associated gastroduodenal ulceration, aspirin plus the proton pump inhibitor esomeprazole was safer than clopidogrel. [vi] There is a concern that clopidogrel might impair ulcer healing and promote ulcer bleeding. [vii]

      Thrombosis and Bleeding

      Drugs that prevent thrombosis tend to cause bleeding, often in the gastrointestinal tract. As more people are treated to reduce the risk of thrombosis or to manage pain, the number of patients exposed to bleeding risk increases. Recently evidence suggests that drugs developed to lower gastrointestinal (GI) bleeding risks such as the cyclooxygenase-2 inhibitors increase the risk of thrombosis. Aspirin, alone or in combination with nonsteroidal anti-inflammatory drugs (NSAIDs), increases the risk of GI bleeding. Clopidogrel is recommended for patients who cannot take aspirin due to GI intolerance and for patients who need additional protection from thrombosis after percutaneous coronary intervention (PCI). Clopidogrel has been found to increase the risk of GI bleeding. Warfarin is a commonly used anticoagulant whose antithrombotic effect is a consequence of the reduction of coagulation factors in the blood.

      [i] Belch J, MacCuish A, Campbell I, et al. The prevention of progression of arterial disease and diabetes (POPADAD) trial: factorial randomised placebo controlled trial of aspirin and antioxidants in patients with diabetes and asymptomatic peripheral arterial disease. BMJ 2008;337:a1840.
      Hiatt WR. Aspirin for prevention of cardiovascular events (editorial). BMJ 2008;337:a1806
      [ii] US Preventive Services Task Force. Aspirin for the prevention of cardiovascular disease: US Preventive Services Task Force recommendation statement. Ann Intern Med 2009; 150:396-404.
      [iii] Sung JJ, Lau JY, Ching JY, et al. Continuation of low-dose aspirin therapy in peptic ulcer bleeding: a randomized trial. Ann Intern Med. 2010;152:1-9.
      [iv] Sabatine, Marc S., Cannon, Christopher P., Gibson, C. Michael, Lopez-Sendon, Jose L., Montalescot, Gilles, Theroux, Pierre, Claeys, Marc J., Cools, Frank, Hill, Karen A., Skene, Allan M., McCabe, Carolyn H., Braunwald, Eugene, the CLARITY-TIMI 28 Investigators, Addition of Clopidogrel to Aspirin and Fibrinolytic Therapy for Myocardial Infarction with ST-Segment Elevation N Engl J Med 2005 Published online www.nejm.org March 9, 2005
      [v] Bhatt D.L. et al Clopidogrel and Aspirin versus Aspirin Alone for the Prevention of Atherothrombotic Events NEJM Volume 354:1706-1717 April 2006
      [vi] Chan FKL et al. Clopidogrel versus aspirin and esomeprazole to prevent recurrent ulcer bleeding. N Engl J Med 2005 Jan 20; 352:238-44.
      [vii] Cryer B. Reducing the risks of gastrointestinal bleeding with antiplatelet therapies. N Engl J Med 2005 Jan 20; 352:287-

      • Topics from the book Heart & Arterial Disease The author is Stephen Gislason MD 2018 Edition: 190 Pages.
      • Major diseases originate from eating too much of the wrong food and damage is done to many organs simultaneously. The evidence does suggest that some interventions are beneficial in terms of preventing heart attacks and strokes and that disease progression can be halted by important changes in diet and increased exercise. The occurrence of a heart attack or stroke confirms that atherosclerosis is advanced, damage has been done and that the rules of intervention have changed. We suggest that a prudent person suffering early vascular dysfunction symptoms would be wise to pursue vigorous, thorough diet revision at the earliest opportunity.

        Order and Download Heart and Artery eBook

        ECG MD


        Order Alpha Education Books

        Alpha Nutrition books, formulas and Starter packs are ordered at Alpha Online. Alpha Education Books refer to the Alpha Nutrition Program standard method of diet revision.

        Click the Add to Cart buttons on the left to begin your order for printed books. Physical shipments are delivered by the Post Office to all destinations in Canada and USA. Prices are listed in Canadian dollars. US $ cost is lower depending on the daily dollar exchange rate.

        eBooks: click download button. We encourage customers to order eBooks rather than print books. The cost of shipping books is increasing. eBooks are low cost with no shipping charges. Payment is made thru PayPal. Downloads are available when the order is paid. Click the book titles in the center column to read topics from the books.

        Print Books Read Topics Download
        Alpha Nutrition Program
        Aching & Fatigue
        Air & Breathing
        Alpha Cooking
        Alcohol Solutions
        Gluten Problems
        Diabetes 2
        Eating & Weight
        Skin Disease
        Feeding Children
        Human Brain
        Managing Food Allergy
        Digestive Disorders
        Food Choices
        Arterial Disease
        Immunology Notes
        Inflammatory Arthritis
        Nutrition Notes
        alpha online

        Alpha Nutrition ® is a registered trademark and a division of Environmed Research Inc., Sechelt, British Columbia, Canada. In business since 1984. Online since 1995.


        • Topics from the book Heart & Arterial Disease The author is Stephen Gislason MD 2018 Edition: 190 Pages

          Major diseases originate from eating too much of the wrong food and damage is done to many organs simultaneously. The evidence does suggest that some interventions are beneficial in terms of preventing heart attacks and strokes and that disease progression can be halted by important changes in diet and increased exercise. The occurrence of a heart attack or stroke confirms that atherosclerosis is advanced, damage has been done and that the rules of intervention have changed. We suggest that a prudent person suffering early vascular dysfunction symptoms would be wise to pursue vigorous, thorough diet revision at the earliest opportunity.

          Order and Download Heart and Artery eBook

          ECG MD


          Order Alpha Education Books

          Alpha Nutrition books, formulas and Starter packs are ordered at Alpha Online. Alpha Education Books refer to the Alpha Nutrition Program standard method of diet revision.

          Click the Add to Cart buttons on the left to begin your order for printed books. Physical shipments are delivered by the Post Office to all destinations in Canada and USA. Prices are listed in Canadian dollars. US $ cost is lower depending on the daily dollar exchange rate.

          eBooks: click download button. We encourage customers to order eBooks rather than print books. The cost of shipping books is increasing. eBooks are low cost with no shipping charges. Payment is made thru PayPal. Downloads are available when the order is paid. Click the book titles in the center column to read topics from the books.

          Print Books Read Topics Download
          Alpha Nutrition Program
          Aching & Fatigue
          Air & Breathing
          Alpha Cooking
          Alcohol Solutions
          Gluten Problems
          Diabetes 2
          Eating & Weight
          Skin Disease
          Feeding Children
          Human Brain
          Managing Food Allergy
          Digestive Disorders
          Food Choices
          Arterial Disease
          Immunology Notes
          Inflammatory Arthritis
          Nutrition Notes
          alpha online

          Alpha Nutrition ® is a registered trademark and a division of Environmed Research Inc., Sechelt, British Columbia, Canada. In business since 1984. Online since 1995.