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  • DIRO Trial: RA Shows Better Results vs. OA in OCT-Guided PCI

    Rotational atherectomy (RA) is associated with larger stent expansion and favorable tissue modification compared to orbital atherectomy (OA) in optical coherence tomography (OCT)-guided percutaneous coronary intervention (PCI), according to a new randomized trial.

    These results were reported by Naotaka Okamoto, MD, of Osaka Rosai Hospital, Osaka, Japan and colleagues in a manuscript published Monday online and in the Sept. 11 issue of JACC: Cardiovascular Interventions.

    All previous studies that compared the efficacy and safety of RA versus OA for severely calcified lesion preparation were observational studies and not performed under the guidance of intracoronary imaging.

    DIRO (to directly compare RA and OA for calcified lesions) was a single-center prospective randomized trial that enrolled patients who underwent PCI for a de novo severely calcified lesion with an arc more than 180° as assessed by OCT or angiographically moderate or severe calcification if the OCT catheter failed to cross through the lesion before any intervention. Patients with ostial left main or right coronary artery lesions were excluded. Subsequently, patients were randomly allocated to undergo lesion preparation with RA or OA. OCT was performed during the PCI and again at 8 months after the stent deployment.

    The study enrolled 100 patients between August 2019 and October 2021, of whom 99 (99%) successfully completed 8 months of follow-up. However, of these, only 37 patients in the RA group and 27 in the OA group received OCT assessment at 8-month follow-up.

    At baseline, the median age was 73.4±9.9 years in the RA group and 74.2±8.7 years in the OA group. The majority of the patients were male (RA 72%, OA 66%). The major risk factors for the included patients were hypertension, diabetes mellitus, and dyslipidemia. Left anterior descending artery lesions were present in 80% of the patients in the RA group and in 58% of the patients in the OA group.

    The efficacy outcomes were stent expansion assessed by distal reference, and tissue modification assessed by the OCT before and immediately after the atherectomy. The safety outcomes included complications after atherectomy and at the end of the procedure, as well as adverse events 8 months after the procedure. Additionally, vascular healing was evaluated using OCT at the 8-month follow-up.

    The study demonstrated significantly greater stent expansion in the RA group compared to the OA group (99.5% vs 90.6%; P = 0.02) and significantly larger maximum atherectomy area in the RA group than in the OA group (1.34 [interquartile range (IQR): 1.02-1.89] mm2 vs 0.83 [IQR: 0.59-1.11] mm2; P = 0.004). Percentage of lumen area increase was 72.2% in the RA group compared to 39.2% in the OA group (P<0.01). The 1.5-mm burr was most frequently used with mean rotation speed of 181,120 rpm. In the OA group, the crown burr size was only 1.25 mm, and a rotation speed of 120,000 rpm was used in 90% of the lesions.

    Procedural outcomes including myocardial infarction, clinical events at 8 months and vascular healing were comparable in both groups.

    In an accompanying editorial, Dean Kereiakes, MD, of Christ Hospital and Lindner Research Center, Cincinnati, stated that this study would draw attention to the significance of intravascular coronary imaging in evaluating the efficacy of calcium-modifying technologies.

    “In conclusion, this work should draw focus on the need for prospective randomized comparisons between calcium-modifying technologies as well as the importance of incorporating systematic, protocol driven, intravascular imaging substudies,” Kereiakes wrote.


    He added that the between-group comparison of late clinical and angiographic outcomes was underpowered, making it difficult to draw reliable conclusions.


    Okamoto N, Egami Y, Nohara H, et al. Direct Comparison of Rotational vs Orbital Atherectomy for Calcified Lesions Guided by Optical Coherence Tomography. JACC Cardiovasc Interv. 2023;16:2125–2136.

    Kereiakes DJ. Atheroablation Imaging Insights. JACC Cardiovasc Interv. 2023;16:2137–2138.

    Image Credit: RFBSIP –

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