New data presented at the 2024 Vascular Annual Meeting (VAM; 19–22 June, Chicago, USA) have revealed poor overall rates of medical therapy adherence in moderate asymptomatic carotid stenosis patients—with smoking cessation representing a “ripe target” for improvement moving forward.
“The objectives of this study were to examine adherence to three common tenets of medical therapy among a cohort of patients treated with medical therapy alone, and then to identify shortfalls in therapy to serve as opportunities for improvement,” said Randall Bloch (St Elizabeth’s Medical Center, Boston, USA), presenting these data on behalf of senior author Mark Conrad (St Elizabeth’s Medical Center, Boston, USA) and colleagues.
Bloch and colleagues’ single-centre, retrospective study involved reviewing consecutive carotid duplex ultrasound scans from 2019–2020. Patients with moderate (50–69%) asymptomatic carotid stenosis—based on Society for Vascular Surgery (SVS) guidelines—were included in the study, while those who underwent upfront surgery “for any reason” were excluded, as were those without available follow-up data.
Patients were assessed for their adherence to optimal medical therapy at the time of the index duplex scan, the first follow-up visit, and at each subsequent follow-up visit until the end of the study, ultimately leading to a median follow-up period of 2.7 years. In the study, optimal medical therapy was defined via three key tenets: abstinence from smoking; use of aspirin or other antiplatelets; and use of statins or other lipid-lowering therapies.
The study, now also published in the Journal of Vascular Surgery, identified a total of 323 duplex ultrasound examinations with moderate asymptomatic carotid stenosis across 255 patients. Bloch reported that 56.1% of these patients were already on all three of the aforementioned aspects of medical therapy at the time of the index duplex, with this rate improving to 68.6% by the end of the follow-up period.
“However,” Bloch continued, “when looking specifically at the 112 patients that were not already on medical therapy, 38.4% were able to achieve adherence to all three tenets of medical therapy by the end of follow-up—and abstinence from smoking was the aspect of medical therapy that was least commonly achieved.”
The presenter went on to highlight the fact that patients with hypertension and those who were not smoking at the outset of the study demonstrated the highest rates of medical therapy adherence. According to Bloch, non-smokers achieving generally better adherence rates was able to be attributed to a rapid, initial uptake in adherence, likely due to “the relative ease of adding additional medications to the regimen, as opposed to the relative difficulty of smoking cessation”. In addition, multivariable analysis revealed that smoking at the time of the index duplex was associated with lower odds of achieving optimal medical therapy adherence.
“In conclusion, adherence to best medical therapy is suboptimal—less than 40% of patients who were not previously on therapy were able to achieve adherence to best medical therapy by the end of follow-up,” Bloch stated. “And, so—despite rapidly evolving medical therapies for cardiovascular risk reduction—smoking cessation remains a ripe target for interventions aimed at adherence to medical therapy.”
Discussions subsequent to Bloch’s presentation saw Kakra Hughes (Howard University, Washington DC, USA) note that these data lead him to a slightly different conclusion.
“I don’t quite agree with your conclusion that best medical therapy is not good [in this study], because it’s 80% adherence when you take away smoking cessation—and we all know that smoking cessation is very difficult,” Hughes said. “I’d consider that the adherence to best medical therapy is about 80%, and I’d conclude that it is pretty good.”
Bloch agreed with Hughes to some degree, echoing his point that medication adherence alone was “pretty good”, but went on to assert that smoking cessation was part of the prespecified regimen in the study and is also recommended by the SVS as well as multiple other societal guidelines.
“So, I think it’s important to continuously look at how we’re doing in terms of providing comprehensive care for these patients,” the presenter added.
Another comment came from session moderator Wei Zhou (University of Arizona, Tucson, USA), who described this as a “really important study”, and suggested that it may have wider implications in other medical areas beyond carotid disease where medication adherence is also poor.
Speaking to NeuroNews following VAM 2024, Bloch provided further context regarding his discussion with Hughes, stating: “Given that smoking cessation is such an integral aspect of best medical therapy, my concern is that separating it from the medication regimen may lead to a false sense of success when it comes to stroke and cardiovascular risk reduction. As such, smoking cessation should be a leading priority in the care of these patients.”
