Ask the Doctors October 2013 Issue

Ask The Doctors: October 2013

Iíve heard that itís even more important to get a flu shot, because having heart disease makes you more susceptible to the flu. Is that true and is it safe? Could it interfere with my medications?

Itís a good thing you asked this question, because the topic affects so many people. First of all, what you heard is absolutely correct. Not only does heart disease increase your susceptibility to viral influenza, but it also increases the risk of serious health complications, including hospitalization. The Centers for Disease Control have a website dedicated to this concern at www.cdc.gov/flu/heartdisease/. During a recent flu season, more than a third of patients hospitalized for influenza also had a history of heart disease. Conditions which make one more prone to flu-related complications include coronary artery disease (CAD), heart failure, valve disease, congenital heart disease, pulmonary hypertension, and arrhythmias. As to your other question, the vaccine does not interact with medications.

Letís look at the subject from another direction. Substantial data gathered by researchers show a clear temporal relationship between influenza and subsequent myocardial infarction (MI). The same has been seen for bacterial (pneumococcal) pneumonia. In other words, these infections can trigger heart attacks. Several mechanisms could explain the connection. CAD is the result of cholesterol deposition in plaques, and subsequent inflammation inside those plaques can lead to rupture. When blood cells such as platelets bind to the ruptured plaque, the coronary artery may become blocked by a blood clot, a situation known as ďcoronary thrombosis.Ē This rapid clot formation in the vessel is the usual cause of acute MI. Influenza and pneumonia produce a high level of inflammation in the entire body, which almost certainly affects coronary plaques as well, increasing the risk of plaque rupture. The physical stress and pain associated with severe infection may also cause constriction of the coronary vessels, reducing bloodflow to a hard-working heart muscle. The key finding of clinical studies is that immunization against influenza reduces the risk of MI and stroke. So, there is no clear downside to getting the flu shot, but there is substantial evidence of benefit.

I take medications and adopted a healthier lifestyle for my high blood pressure and high cholesterol. I donít have a cardiologist, just a primary care physician (PCP). When should I or anyone who is starting to deal with these issues start to see a specialist?

Anyone who has established heart disease, or has ever had a heart attack, heart surgery, or endovascular procedure (such as stent placement, arrhythmia ablation or transcatheter valve insertion) should see a cardiologist on a regular basis. And if symptoms are present which suggest underlying, undiagnosed heart disease, then referral to a cardiologist is indicated, as well. It seems obvious that medical care for specialized problems like blocked coronary arteries would be better performed by specialized physicians (cardiologists), and indeed this is what studies show. However, the case is not as clear for preventive care, involving the treatment of conditions like hypertension and high cholesterol. For example, clinical data suggest that these risk factors may be handled more effectively by the PCP. Some generalists actually have areas of clinical expertise, such as high blood pressure, and do outstanding work treating it. A good rule of thumb is that if the PCP is having difficulty managing risk factors, then it is time to consult a specialist. This does not always mean a cardiologist, since nephrologists (kidney doctors) often focus on hypertension, and endocrinologists (hormone specialists) frequently treat hyperlipidemia. However, heart doctors in the areas of general cardiology or the newer field of preventive cardiology would be great choices for further care, if necessary.

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