Ask The Doctors: November 2019
Q: I had a heart attack and received two stents. How long do I have to take blood thinners?
A: If you have a drug-eluting stent (DES), it is common to use aspirin along with another antiplatelet drug, such as clopidogrel or prasugrel, to reduce the risk of a blood clot in the stent leading to heart attack. This treatment is known as dual antiplatelet therapy (DAPT). The risk is highest in the first 30 days after stenting and then falls, but never completely disappears.
The duration of DAPT depends on the reason for stenting (stable heart disease versus acute heart attack), the type of stent used and the patient's clotting and bleeding risks. Because the clotting risk is high after a recent heart attack, in your case there is strong data to support DAPT for at least one year. One recent clinical trial demonstrated a lower late clotting risk but more bleeding events with 30 versus 12 months of DAPT. This suggests patients with high clotting risk but low bleeding risk may benefit from taking DAPT longer.
The SMART-CHOICE trial found that DAPT for three months followed by clopidogrel alone versus DAPT for 12 months reduced bleeding events without increasing clotting episodes. American College of Cardiology guidelines now recommend considering stopping DAPT at three months for DES in stable heart disease and six months for DES following heart attack in patients with high bleeding risk. High clotting risk (influenced by recent heart attack, diabetes, heart muscle dysfunction, characteristics and types of stents used) favors longer DAPT. High bleeding risk (associated with previous bleeding history, chronic kidney disease, advanced age and other anticoagulant use) favors shorter DAPT. Since this decision requires careful assessment of risks and benefits, you should never stop DAPT without consulting your cardiologist. Regardless of the duration of DAPT, most cardiologists agree that low-dose aspirin be continued for life.
Q: Why does a nurse take my heart rate every time I go to the doctor's office?
A: The number of times your heart beats per minute (bpm) is called your heart rate (HR), or pulse. Your HR at rest is a fast and simple measurement that helps your doctor gain insight into your overall and cardiovascular health. HR is not a stable value and increases or decreases in response to the body's physical needs. A normal resting HR ranges from 60 to 100 bpm. HR higher than 100 bpm (tachycardia) is abnormal.
HR normally increases in response to pregnancy, stress or anxiety, excessive caffeine intake or fatigue. A high HR also may indicate an abnormal underlying condition, such as infection, anemia, dehydration, low blood oxygen level, overactive thyroid, heart muscle dysfunction, valvular heart disease, lung disease or blood clots in the lungs. Numerous studies have shown that a higher resting HR is linked to increased risk of cardiovascular events and death. This is not surprising, given that a high resting HR is associated with poor physical fitness, higher blood pressure, obesity and elevated levels of fats in the blood.
HR also increases when the heart is unable to pump blood efficiently; thus it serves as an important indicator of risk in heart failure. A low resting HR less than 60 bpm (bradycardia) may indicate physical fitness, but also may suggest problems with the heart's electrical system. This finding is particularly helpful if noted in the setting of fatigue, dizziness or fainting. An irregular pulse may be a clue to an arrhythmia such as atrial fibrillation. Your doctor also may use HR to gauge the effectiveness of treatments or to adjust medications you are taking for heart disease.