Coronary microvascular dysfunction and short-term outcomes after PCI for severely calcified lesions: a comparison between intravascular lithotripsy and rotational atherectomy

Background Treatment of calcified coronary artery stenosis remains challenging and is associated with worse clinical outcomes. For successful PCI of calcified lesions, it is imperative to achieve sufficient plaque modification before stent implantation. However, the impact of different calcium-modification technique on the coronary microcirculation remains unclear. Aims The aim of this study is to evaluate the influence of plaque modification techniques on coronary microcirculation with severely calcified coronary artery lesions. Methods We retrospectively analyzed physiological measurements and procedural outcomes of 94 patients who underwent PCI for severely calcified coronary stenosis treated with calcium-modification devices from January 2022 to December 2025 at our hospital. Coronary microvascular function was assessed using a temperature-sensor pressure guidewire before and after PCI. The primary endpoint was impairment of coronary microvascular resistance and reserve assessed by the index of microvascular resistance (IMR), resistive reserve ratio (RRR), and microvascular resistance reserve (MRR). Secondary endpoints included periprocedural complications and short-term clinical outcomes. Coronary microvascular dysfunction (CMD) was defined as IMR≧25. Results A total of 48 patients underwent calcium modification with intravascular lithotripsy (IVL) and 46 with rotational atherectomy (RA). The mean age was 76 years, 74% were male and the left anterior descending artery was the most frequently treated vessel. Baseline physiological data were comparable between groups. FFR improved significantly after PCI in both groups. In the IVL group, IMR did not significantly change (median 15.0 [IQR 9.0-22.0] to 12.0 [IQR 9.0-19.0], p=0.27), while coronary microvascular reserve improved, with increase in RRR (median 2.5 [IQR1.8-3.65] to 3.0 [IQR 2.12-4.60], p=0.03), and MRR (median 2.33 [IQR 1.65-3.44] to 2.77 [IQR 2.05-4.54], p=0.01). In contrast, in the RA group IMR increased (median 14.0 [IQR 10.75-21.00] to 17.5 [IQR 11.25-36.5], p<0.01) and RRR decreased (median 2.50 [IQR 1.68-3.30] to 1.55 [IQR 1.20-2.35], p=0.04) (Figure1), suggesting post-PCI impairment of the coronary microcirculation. The rate of post-PCI CMD was lower in IVL group than in the RA group (10% vs. 36%, p<0.01). Periprocedural MI and slow flow during PCI were more frequent in the RA group (26% vs 4%, p<0.01; and 20% vs 4%, p=0.03, respectively) (Figure 2). On multivariable logistic regression, RA emerged as an independent predictor of post-PCI CMD (odds ratio 5.41, 95% confidence interval 1.60–18.3; p<0.01). Conclusion IVL and RA are both effective devices to treat severely calcified coronary stenosis . However, IVL was associated with a lower incidence of CMD than RA, suggesting that consideration on device selection would be required in high risk patients with severely calcified coronary disease.