DOCTORS: Optical Coherence Tomography Improves Stent Placement, Ups FFR in NSTE ACS
ROME, Italy—(UPDATED) The addition of optimal coherence tomography (OCT) to standard fluoroscopy can influence physician decision-making and quantitatively improves post-PCI fractional flow reserve (FFR) in patients with non-ST-elevation acute coronary syndromes, results from the DOCTORS trial show.
The study, said lead author Nicolas Meneveau, MD, PhD (University Hospital Jean Minjoz, Besançon, France), is the first randomized controlled trial to support a role for OCT in this setting, although hard clinical endpoint studies are warranted.
“We need additional data,” he acknowledged in a morning press conference. “We need additional studies with clinical endpoints before considering incorporating OCT as the standard to use in ACS patients. But this is an important first step—the first randomized controlled trial showing the potential positive effect by FFR on the results of PCI in ACS patients.”
Indeed, as study co-author François Schiele, MD (Université de Franche Comté, Besançon, France), pointed out to TCTMD, this kind of validation study was never done for IVUS, despite two decades of use. “IVUS is dead,” Schiele said—at least in the setting of stent optimization; Schiele conceded that IVUS remains an important tool for visualizing plaque progression and regression. And for physicians already using OCT in their practice, this study is the first to show that using it as an add-on in select patients is safe and leads to better stent usage and placement.
Meneveau presented the results in a hotline session at the European Society of Cardiology Congress 2016. The study was published simultaneously in Circulation.
The DOCTORS Advice
DOCTORS randomized 240 NSTE ACS patients to OCT-guided PCI (with OCT being used both pre- and post-PCI) or to angiography only. Use of OCT led to a change in procedural strategy in half of the patients randomized to this group. Preprocedure OCT tended to have a minimal impact on physician decision-making, although patients imaged with OCT were more likely to receive glycoprotein IIb/IIIa inhibitors, typically because of thrombus showing up on OCT. Following stent implantation, however, OCT led to the identification of stent malapposition, stent underexpansion, and edge dissection. As such, additional inflations and additional stent implantation were more common in the OCT group.
In all, OCT led to procedure optimization in 50% of patients as opposed to 22% in the angiography-guided group (P < 0.0001).
This dovetailed with a lower rate of diameter stenosis at the end of PCI in the OCT group as compared with the angiography only group (7.0% vs 8.7%; P = 0.01).
Fractional flow reserve (FFR), measured by pressure wire following the procedure—the primary endpoint of the study—was significantly higher in the OCT group than in the angiography-only group: 0.94 ± 0.04 versus 0.92 ± 0.05 (P = 0.005).
FFR, Meneveau added, is an established surrogate for improved outcomes in PCI. “The higher the FFR the lower the event rate,” he said. “That’s something that has been previously reported in many prospective randomized controlled trials.”
Of note, however, improved FFR and stent placement was achieved at the cost of significantly greater procedure time, contrast use, and radiation exposure. Rates of myocardial infarction and acute kidney injury, however, were no different between groups. Clinical outcomes, including major adverse cardiac events and stent thrombosis, also did not differ. This is important, Schiele told TCTMD, adding that he’d predicted they might see a safety signal with OCT, given the high-risk nature of the patient group.
“If OCT is safe in this situation, it is probably safe for all patients,” Schiele said. “So safety is probably a very good insight from this study.”
Asked whether an absolute improvement of 0.02 FFR units was enough to offset the increased contrast dose and radiation usage, Meneveau conceded that this will need to be established in future studies. That said, the nature of the study protocol required multiple OCT runs—something he believes could be reduced in practice, thereby reducing contrast volume and radiation exposure.
Moreover, said Schiele, the degree of improvement in FFR differed between patients such that some saw no improvement and others saw improvements of .05 units, something he characterized as “very significant.”
Commenting on the study for TCTMD, however, Giulio Guagliumi, MD (Ospedale Papa Giovanni XXIII, Bergamo, Italy), pointed out that to the best of his knowledge, the association between improvements in FFR and clinical outcomes has only been demonstrated in registry studies, not in prospective randomized clinical trials.
Moreover, Guagliumi also had concerns about the generalizability of the DOCTORS findings to a wider population. He noted that the average age of the study population was relatively young, with low rates of hypertension and diabetes. Lesions treated were also very short—in the range of 13 mm. OCT, he said, may play a better role in longer, less focal lesions, where OCT can help with the decision of whether to use a longer or shorter stent. Finally, a “huge amount” of abciximab was used, he noted. This was coupled with a relatively high rate of periprocedural MI.
“If you want to impact on clinical outcomes with OCT, [periprocedural MI] is the major complication that you need to change, and in fact it was very high and totally similar between groups,” he said.
Guagliumi also stressed that there was no description of how the OCT procedure or image interpretation was standardized in the study, which also limits its generalizability to other populations. “There is still a lot of uncertainty. It is interesting to use FFR as a surrogate to show some possible benefit, but it needs to be applied in a prospective study with clear evidence of outcome, and using much more well-defined instructions on how to guide the procedure,” he concluded.
- Meneveau N, Souteyrand G, Motreff P, et al. Optical coherence tomography to optimize results of percutaneous coronary intervention in patients with non-ST-elevation acute coronary syndromes. Results of the multicenter, randomized DOCTORS (Does Optimal Coherence Tomography Optimize Results of Stenting) study. Circulation. 2016;Epub ahead of print.
- Meneveau reports consulting fees and speaker honoraria (modest) from St. Jude Medical, Bayer, Daiichi Sankyo, Astra-Zeneca, and BMS-Pfizer and speaker honoraria from Boehringer Ingelheim.
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