Pot Use Raises Risks After Severe Form of Stroke
FRIDAY, Jan. 7, 2022 (HealthDay News) — If you have any risk factors for stroke and you like to smoke pot, a new study suggests you should stop toking.
Researchers found that people with an aneurysmal subarachnoid hemorrhage, a rare, severe type of bleeding stroke, who had used marijuana three to 30 days before their stroke were twice as likely to develop a dangerous complication that can lead to greater disability or death.
The study was the largest to consider the impact of THC, the component in marijuana that makes someone high, on complications after this type of stroke.
“We’re all vulnerable to a bleeding stroke or a ruptured aneurysm, however, if you’re a routine marijuana user, you may be predisposed to a worse outcome from a stroke after the rupture of that aneurysm,” said senior study author Dr. Michael Lawton, president and CEO of Barrow Neurological Institute in Phoenix.
His team analyzed data on more than 1,000 patients who had been treated for an aneurysmal subarachnoid hemorrhage at the institute between Jan. 1, 2007 and July 31, 2019.
All the patients had been treated to stop the bleeding one of two ways: by threading a slim tube through a blood vessel to the base of the aneurysm and releasing coils that provide a barrier to further bleeding; or through full-blown surgery to clip off the base of the aneurysm.
Urine toxicology screening was done for all patients admitted with ruptured aneurysms.
In an aneurysmal subarachnoid hemorrhage, a weakened and bulging part of a blood vessel bursts on the surface of the brain. This is called a ruptured aneurysm. It results in bleeding in the space between the brain and the tissue that covers it and can cause neurological disability for 66% of people and death for 40%.
The immediate treatment focuses on stopping and preventing further bleeding. Yet, in the 14 days following this type of stroke, patients may develop worsening symptoms, such as speech problems or difficulty moving.
This complication, called a delayed cerebral ischemia, happens when blood from the initial stroke irritates blood vessels, causing them to constrict enough to cut off the blood supply to a portion of the brain (called vasospasm).
The study compared the occurrence of delayed cerebral ischemia in 46 people who tested positive for THC and 968 people who tested negative for THC.
The recent cannabis users did not have significantly larger aneurysms or worse stroke symptoms when admitted to the hospital. They were also not more likely to have high blood pressure or other cardiovascular risk factors than patients who screened negative for THC. They were significantly more likely to have also tested positive for other substances, including cocaine, methamphetamines and tobacco, compared to the patients who screened negative for THC.
Among all participants, 36% developed delayed cerebral ischemia, 50% were left with moderate to severe disability and 13.5% died.
The researchers found that those who tested positive for THC were 2.7 times more likely to develop delayed cerebral ischemia, 2.8 times more likely to have long-term moderate to severe physical disability and 2.2 times more likely to die.
The findings were published Jan. 6 in the journal Stroke.
“When people come in with ruptured aneurysms, and they have a history of cannabis use or are positive on a toxicology screen, it should raise a red flag to the treating team that they are at higher risk of vasospasm and ischemic complication,” Lawton said in a journal news release.
“Of all the substances detected in the toxicology screen, only cannabis raised the risk of delayed cerebral ischemia,” he said. “Cocaine and meth are hypertensive drugs, so they are likely related to the actual rupture but not expected to have an impact on vasospasm.”
The researchers are now conducting follow-up in the laboratory to better understand THC-related risks that may impact aneurysm formation and rupture. They also urge further research to study the impact of various doses of THC on stroke complications.
“Evaluating the risks and benefits of marijuana use is more important, given its popularity and as more states make recreational marijuana use legal,” Lawton said.
The U.S. National Institute of Neurological Disorders and Stroke has more on cerebral aneurysms.
Marijuana Use Risky After Aneurysm Rupture?
Smoking marijuana may be risky after aneurysmal subarachnoid hemorrhage (aSAH).
A new study shows a significant association between cannabis use and delayed cerebral ischemia (DCI) after aneurysm rupture, with nearly three times the risk of DCI and poor functional outcome.
“Aneurysms are found in 3% of the population, but only a small fraction (approximately 1%) rupture per year. Therefore, our findings affect a small portion of the overall population,” Michael T. Lawton, MD, senior author and president and CEO of Barrow Neurological Institute in Phoenix, Arizona, told Medscape Medical News.
“However, patients with a known aneurysm that is being managed conservatively with observation may want to reconsider their cannabis use in the event that their aneurysm ruptures,” said Lawton.
The study was published online January 6 in Stroke.
Largest Study to Date
The researchers reviewed the records for all 1014 patients treated for aSAH at Barrow Neurological Institute over 12 years. All of them underwent urine toxicology screening on admission.
Overall, 367 patients (36.2%) had DCI, 509 (50.2%) had poor functional outcome (modified Rankin Scale score >2) and 137 (13.5%) died.
A total of 46 (4.5%) patients (mean age, 47 years; 41% women) had a positive urine test for tetrahydrocannabinol (THC), while 968 (mean age, 56 years; 71% women) tested negative for THC.
The rate of DCI was significantly higher in THC-positive aSAH patients than in peers who tested negative (52.2% vs 35.4%; P = .03).
A positive urine screen for THC reflects cannabis use within 3 days for a single use to within roughly 30 days for frequent heavy use.
In propensity score–adjusted binary logistic regression analysis, cannabis use was independently associated with an increased likelihood of DCI (odds ratio, 2.7; 95% CI, 1.4 – 5.2; P = .003).
A prior study found a similar relationship between cannabis use and DCI in 108 patients with aSAH.
“Our study confirmed this in the largest study to date in over 1000 patients,” Lawton told Medscape Medical News.
Cocaine, methamphetamine, and tobacco use were not associated with DCI (P ≥ .29).
The study also showed a higher rate of angiographic vasospasm in cannabis users than nonusers (88.9% vs 70.5%; P = .008).
DCI was present in 50.0% of cannabis users with vasospasm vs 39.0% of nonusers (P = .17), which supports vasospasm as a potential reason for increased DCI, the researchers say.
“When people come in with ruptured aneurysms, and they have a history of cannabis use or are positive on a toxicology screen, it should raise a red flag to the treating team that they are at higher risk of vasospasm and ischemic complication,” Lawton said in an AHA news release.
“Of all the substances detected in the toxicology screen, only cannabis raised the risk of delayed cerebral ischemia,” he noted.
But the authors of an accompanying editorial in Stroke caution that more study is needed to determine the pathophysiology of cannabis-related cerebral ischemia.
“Ultimately, given the prior mixed results regarding the association of marijuana with cardiovascular complications, ischemic stroke or hemorrhagic stroke, it remains an open question whether cannabis precipitates cerebral ischemia via cerebral vasospasm and delayed cerebral ischemia,” write Feras Akbik, MD, PhD, and Ofer Sadan, MD, PhD, with Emory University School of Medicine, Atlanta.
“Future studies should attempt to better quantify the cannabis exposure in terms of chronicity, dose and temporal relationship between the cannabis use and the aneurysm rupture event, in order to better understand whether indeed marijuana can precipitate cerebral ischemia,” Akbik and Sadan say.
In the AHA news release, Robert L. Page II, PharmD, of the University of Colorado, Aurora, said the current study is not at the level of science of a randomized controlled trial, “but it is a rigorous statistical analysis involving more than 1000 patients, so the results are important and add to what we already know about possible adverse effects of marijuana use.”
Page chaired the American Heart Association (AHA) 2020 scientific statement on medical marijuana, recreational cannabis and cardiovascular health.
The statement concluded that evidence for a link between cannabis use and cardiovascular health remains unsupported, and the potential risks outweigh any potential benefits.
The study had no funding. The authors and editorial writers have no relevant disclosures.
Stroke. Published online January 6, 2022. Abstract, Editorial
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