Ask The Doctors: July 2019
Q: I had a heart attack two years ago and was stented. Six months ago I had knee surgery, and can't seem to manage the pain without opioids. Could they be hurting my heart?
A: We are increasingly aware of the dangers of opioid overdose and addiction, but emerging data now highlight the potential for heart and respiratory complications, as well.
Opioids are very effective at pain control, but their known effects on the heart include slowing heart rate, blood vessel dilation leading to low blood pressure and increased risk of arrhythmias, such as atrial fibrillation and ventricular tachycardia.
In a 2016 study of 23,000 patients, opioid users were twice as likely to die from cardiovascular (CV) and respiratory problems than from an overdose. A 2019 study found that at 90 days after discharge, there was a slight increase in the death rate among heart patients, mostly from breathing difficulties during sleep, heart rhythm irregularities and other CV complications. Opioids can exacerbate sleep apnea, increase mortality from chronic obstructive pulmonary disease and depress heart muscle function when combined with benzodiazepines such as Valium.
Such studies only describe associations with opioid use. They don't prove opioids were the actual cause of death. However, considering the known detrimental cardiac effects of opioids, it is reasonable for heart patients to be careful about using opioids long term for pain control. Increased heart rate and blood pressure associated with opioid withdrawal also can be hard on the heart.
On the flip side, physiologic responses to pain can also stress the heart. In some patients, the improvement in function gained through short-term use of opioids may outweigh the risks. However, opioid use needs to be individualized. If your pain has required long-term opioid use, it is time to consider seeing a pain specialist to discuss alternative therapies and withdrawal strategies. Do not stop "cold turkey," but pursue professional supervision.
Q: I recently had a heart attack, but a cardiac catherization found no blocked arteries. Is this possible?
A: Myocardial infarction (MI) in the absence of obstructive coronary artery disease (MINOCA) accounts for 5 to 6 percent of heart attacks. Compared with other MIs, patients are usually younger and more likely to be female. Causes include disruption of a non-obstructive plaque leading to temporary clotting of the coronary artery (CA), transient spasm of a large CA, microvessel disease, a spontaneous tear or dissection of the CA and blood clot or embolism in a CA.
The diagnosis of MINOCA is based on abnormalities in blood enzymes that indicate damage to the heart muscle. A catherization will show no evidence of obstruction and confirm no artery is blocked 50 percent or more. Other imaging tests will identify a localized area of heart muscle injury.
Cardiac magnetic resonance imaging or direct imaging of the interior of the CA may be helpful if the diagnosis is unclear. Patients should be evaluated for an increased tendency to form blood clots. It is important to exclude other causes that may masquerade as MI. Because MINOCA has a variety of causes, uncovering the correct one is necessary to choose appropriate treatment. These may include calcium channel blockers for spasm or intensive anticoagulation to deter blood clot formation.
The prognosis depends on the underlying cause and treatment strategy. A better understanding of MINOCA from ongoing studies is needed to truly understand the prognosis. Regardless, studies suggest that patients with MINOCA who receive standard therapy for MI (aspirin, beta-blockers, ACE inhibitors and statins) have a better long-term outcome than those who do not.