By Denise Williams | News & Views
Your cardiopulmonary rehab participant might be smoking a little dope.
Federal health survey data indicates that at least 2 million Americans living with cardiovascular and/or pulmonary disease engage in some level of cannabis use, according to Paul Oh, MD, MSc, FRCPC, FACP, FAACVPR, which means that your patient could easily be among them. Considering the significant uptake and purported health benefits, is it really that big a deal and should CR/PR professionals be concerned? The blunt answer recently suggested by Dr. Oh – associate professor of medicine and clinical pharmacology at the University of Toronto and medical director of the University Health Network’s cardiac rehab program there – is “maybe.”
There simply isn’t enough high-quality evidence to draw robust conclusions about risks and benefits of cannabis use, he informed members of the Tri-State Society of Cardiovascular and Pulmonary Rehabilitation, AACVPR’s Pennsylvania, Delaware and New Jersey affiliate. The audience, gathered for the third and final online segment of TSSCVPR’s 38th annual symposium, heard that more randomized controlled trials are needed to fill in the evidence gaps. However, ethical and legal considerations must also be addressed before that can happen, said Dr. Oh, who also has professional ties to Kite Research Center and GoodLife Fitness.
The Highs and Lows
What is known at this point, Dr. Oh reported during the June 28 virtual presentation, is that cannabis is indeed associated with a host of anti-inflammatory and pain-relieving properties that may make it valuable and viable under some medical scenarios. It also is believed to have potential neuroprotective, antiemetic, anticonvulsant, antianxiety and antipsychotic characteristics. “From the medical perspective,” the speaker acknowledged, “there are lots of things that cannabis can do.”
At the same time, he added, the literature describes many decidedly adverse effects of cannabis on the body’s cardiac and pulmonary systems. For the former, that includes but is not limited to arrhythmia, increased angina, myocardial infarction, cardiac death and cardiomyopathy. For the latter, think hyperinflation of the lungs, increased airway resistance and possibly greater rate of infection. That’s not even the exhaustive list; but considering the enormous number of people who use cannabis, Dr. Oh emphasized that these events are not exceedingly common. However, for the same reason – incredibly high utilization – he surmised that the medical community can expect to start seeing more of these complications being reported.
Different Tokes for Different Folks
Certainly, older adults represent one segment of the CR/PR population with growing use of cannabis. In terms of etiology, a 65-year-old woman presenting with coronary artery disease likely developed her symptoms due to some other cause than occasional cannabis use. But a bigger concern with this demographic is polypharmacy. “For the people we see who are seniors with cardiovascular disease and other comorbidities, pharmacology can be quite complex,” Dr. Oh remarked, as people in this age bracket tend to take more prescriptions and therefore are more vulnerable to unfavorable interactions (e.g., with cannabidiol and common cardiac medications) if they also partake in cannabis.
It doesn’t help, Dr. Oh added, that the potency of cannabis has changed over time, becoming increasingly concentrated. Furthermore, thanks to “drug designers,” he commented that some illicit products available today might contain as much as 80-90% Delta 9-tetrahydrocannabinol (THC) – one of the active ingredients in marijuana. THC is the main compound that excites – or overstimulates if taken in larger doses – the heart, cardiovascular system and brain.
What is also raising eyebrows is the emerging pattern in the literature of “unusual cardiac risk in young people” who routinely smoke pot – especially younger males, who are landing in the ER and later in cardiopulmonary rehab after presenting with chest pains and myocardial infarction. Dr. Oh devoted several minutes of his talk to a phenomenon known as “takotsubo cardiomyopathy,” ballooning of the heart that normally affects middle-aged and older women and is triggered by emotional stress. Over the past decade or so, there have been more reports of men in their 30s, with no cardiovascular risk to speak of, developing this syndrome. “It seems like marijuana use is an important predictor of this and doubles the risk of developing takotsubo,” he noted. “There is something about cannabis use in some people that predisposes to coronary problems. There are case reports of young people coming in with syncope and ventricular tachycardia, and it seems like their only significant risk factor is that they’re habitual marijuana users.”
Another user group to keep an eye on is the vaping community. THC cartridges are popular with this crowd, but Dr. Oh pointed to recent evidence of e-cigarette or vaping associated lung injury (EVALI). “This has been an important phenomenon, for sure, and we shouldn’t forget this,” he said, noting that the issue was put on the back burner during the COVID-19 pandemic.
Another very important issue, he argued, is about the close interplay between cannabis use and tobacco smoking. Correlations between adverse effects and cannabis are largely pinned on the substance in its inhaled form, Dr. Oh reminded the TSSCVPR practitioners. “Burning or inhaling anything is probably not good for the heart or lungs,” he said, noting that co-use of tobacco and marijuana is high. “Many smokers are tokers,” he said, “but most tokers are smokers.” Because there may actually be some redeeming medical qualities, Dr. Oh suggested that perhaps another route of consumption – oral or topical – might allow for safer use of cannabis in patients with a true need and the potential for real benefit.
What to Do with What We Know
Aside from perhaps encouraging patients to explore cannabis in non-inhaled forms, Dr. Oh summed up his talk with a call to learn from what we already know and explore to find out what we don’t. Patient screening on intake into CR/PRs is critical, for example. He said the assessments should ask about history of use; any concurrent drug use; and details about the individual’s frequency, quantity and preferred method of intake. “We need to know everything that people are doing, so that we can give the best advice,” he explained. Since intake screenings already ask about behaviors like alcohol use and cigarette smoking, inquiring about cannabis use is a natural extension.
Additionally, providers should not be afraid to enter into candid discussions with their charges, in order to identify potential drug interactions and to educate the patient on the potential cardiovascular risks of cannabis use. “There’s a broad range of what it does physiologically but that then may translate to what happens clinically, from symptoms to clinical events to even morbidity and mortality,” Dr. Oh stated. “Acknowledge where there might be some risks, and also where there might be some benefits. We should also identify opportunities where we might want to send people to our friends like the pharmacist to look deeper into possible drug interactions. And, hopefully, over time the research in the area is going to be better.”