‘Urgent action needed’ to improve implementation of guideline-directed medical therapy for PVI

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Kim G Smolderen and Carlos Mena-Hurtado

Almost one-half of the patients receiving a peripheral vascular intervention (PVI) in the Society for Vascular Surgery (SVS) Vascular Quality Initiative (VQI) registry between 2017 and 2018 were not on guideline-directed medical therapy (GDMT). Kim G. Smolderen, PhD, and Carlos Mena-Hurtado, MD, both from Yale University School of Medicine in New Haven, Connecticut, with their Vascular Medicine Outcomes (VAMOS) team report this and other key findings from a recent study in JACC: Cardiovascular Interventions.

The researchers note there has been a “rapid rise” in the volume of PVIs over the last decade, which stands in contrast to what they describe as “clinical inertia” for implementing GDMT in peripheral arterial disease (PAD). The team hypothesized that a lack of GDMT in patients undergoing PVIs may increase mortality and amputation risk and therefore sought to study the association between GDMT and mortality/amputation and to examine GDMT variability among providers and health systems.

Smolderen et al performed an observational study using patients in the VQI registry who underwent PVI during the one-year study period, deriving two-year all-cause mortality and major amputation data from the Medicare claims database. The investigators defined compliance with GDMT as receiving a statin, antiplatelet therapy, and angiotensin-converting enzyme inhibitor/angiotensin receptor blocker if hypertensive. They applied propensity 1:1 matching for GDMT versus no GDMT and performed survival analyses to compare outcomes between groups.

The team identified 15,891 patients (mean age, 72) who underwent a PVI in the 2017–18 period, specifying that 48.8% received GDMT and that 6,120 patients in each group were matched. They note that median follow-up was 9.6 months for mortality and 8.4 months for amputation.

Writing in JACC: Cardiovascular Interventions, Smolderen and colleagues report that mortality risk was higher among patients who did not receive GDMT versus those on GDMT (31.2% vs. 24.5%), as was risk of amputation (16% vs. 31.2%). GDMT rates across sites and provider ranged from 0% to 100%, the authors add, noting that lower performance translated into higher risk.

In their conclusion, Smolderen and colleagues summarize that one-half of the patients receiving PVI do not receive optimal GDMT and face an almost 40% increased risk of mortality, and an almost 20% increased risk of major amputation in the two years following their procedure. Speaking to the fact that GDMT rates were “highly variable” across sites and providers, they suggest this highlights “modifiable” rates and comment that “performance can be improved.”

“Offering PVIs without optimal GDMT is a low-value proposition for the patient, their families, health systems, and society at large,” the authors write. In light of this, they stress that “urgent action is needed to ensure the delivery of high-value PAD care as part of the interventional pathway.”

Considering what form this action might take, Smolderen et al state that, as part of the “PVI pathway,” national quality and reporting systems should be developed and tested to improve GDMT rates in patients with PAD.

The authors acknowledge some limitations to their study, including the fact that they limited quality metrics to three medications only, and that there is the “potential for unmeasured residual confounding” in the study due to its observational nature.

‘Time to step on the gas’

In an editorial comment, also published in JACC: Cardiovascular Interventions, Connie N. Hess, MD, and Marc P. Bonaca, MD, of the University of Colorado School of Medicine in Aurora, Colorado, write that Smolderen and colleagues’ study “adds additional confirmatory evidence of the persistent gap between guidelines and real-world treatment”.

However, they also stress that the observations of the analysis with respect to outcomes should be interpreted with caution. They elaborate that while randomized clinical trials have demonstrated that the individual components of GDMT can reduce major adverse cardiovascular events (MACE) in patients with vascular disease, including PAD, none of these therapies has been proven in randomized trials to reduce all-cause mortality or major adverse limb events (MALE). This, they write, makes it “difficult to infer a causal relationship between GDMT and improved survival and freedom from amputation.”

They deem Smolderen et al’s study an “impressive effort,” although stress that the analysis “illustrates the complementary nature of randomized trials and observational investigations,” labelling the former the “gold standard” for assessing the actual efficacy and safety, and the latter “necessary to understand use in practice and to generate additional hypotheses for further testing in trials”.

The study, Hess and Bonaca conclude, provides a “sobering reminder of the continued gap in PAD care that will continue to persist without better data and the new focus on implementation.” Clinical care “remains paramount,” they say, noting however that there is a need for “accelerated action” to speed up the “glacial pace” of translation of evidence to practice. Newer medical therapies for PAD are already available, they stress, but in terms of implementation, it is “time to step on the gas.”

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