Not all calcium modification devices interact with the treated vessel in the same way. Although the clinical goal is the same —to facilitate angioplasty and optimize stent implantation— the immediate effect on coronary flow, pressure, and the microcirculation may vary according to the ablation mechanism used.
The ORACLE study compared orbital atherectomy (OA) versus rotational atherectomy (RA) in patients undergoing PCI for severely calcified coronary lesions, with a specific focus on the immediate physiological impact on the microcirculation. The authors hypothesized that OA would produce less microcirculatory impairment than RA, partly because it allows continuous flow during ablation and requires a higher-flow flush system.
A 1:1 randomized study was conducted including 40 patients assigned to OA or RA. Patients with native vessel lesions, reference vessel diameter between 2.25 and 3.50 mm, and severe calcium length greater than 20 mm were included. Left main lesions, RCA ostial lesions, and CTOs were excluded. The protocol included baseline physiological assessment, immediate post-atherectomy measurements, and final evaluation after stent implantation and optimization.
The primary endpoint was post-atherectomy index of microcirculatory resistance (IMR). Secondary endpoints included coronary flow velocity, FFR, coronary flow reserve, coronary wedge pressure, peri-atherectomy systolic blood pressure, ablation times, and need for temporary pacemaker activation.
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Mean age was 66 years in both groups, with a high prevalence of hypertension, dyslipidemia, and diabetes. Left ventricular ejection fraction was 50% in both groups. From an angiographic standpoint, all lesions were classified as severely calcified, with similar reference vessel diameters and percent stenosis, although lesion length was greater in the RA group (44 mm vs 34 mm).
Regarding the procedure, total procedural duration was longer with the rotational strategy: 138 min vs 118 min with OA (p=0.001). However, ablation times were longer with OA (102 sec vs 50 sec). The lowest systolic blood pressure during atherectomy was significantly lower in the RA group: 85 mmHg vs 102 mmHg with OA (p=0.02).
The primary endpoint demonstrated a clear physiological difference immediately after ablation. Post-atherectomy IMR was lower with OA compared with RA: 16 vs 25 (p=0.008). This finding was accompanied by higher post-atherectomy coronary flow velocity in the orbital group: 4.5 vs 2.4 (p=0.04). However, by the end of the procedure, after stent implantation and optimization, these physiological differences were attenuated, with no significant differences in final FFR, final coronary flow, or final coronary flow reserve.
Conclusions: Orbital atherectomy showed less acute microvascular injury than rotational atherectomy
The authors concluded that orbital atherectomy was associated with less acute microvascular injury than rotational atherectomy, reflected by lower IMR and higher coronary flow immediately after ablation. However, these differences normalized by the end of the procedure, highlighting the dynamic nature of the microcirculation during PCI.
Reference: Presentado por Filippo Luca Gurgoglione en EuroPCR 2026 Late-Breaking Trials, 19-22 de mayo de 2026, París, Francia.
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