Background: Coronary CT angiography (CCTA) is a key non-invasive tool for evaluating coronary artery disease (CAD). While energy-integrating detector CT (EID-CT) offers high negative predictive value (NPV), its positive predictive value (PPV) is limited in heavily calcified vessels. Photon-counting detector CT (PCD-CT), with higher spatial resolution and reduced blooming, may enhance diagnostic performance. Current PCD-CT systems provide both standard-resolution (SR) and ultra-high-resolution (UHR) modes, but the clinical impact of these modes remains under investigation.

Objectives: To compare the diagnostic accuracy and image quality of SR-PCD-CT versus EID-CT in quantifying coronary stenosis, using quantitative coronary angiography (QCA) as reference. Materials and methods: In this prospective, single-centre study, 21 patients (5 women, mean age 71.5 years) with suspected CAD underwent CCTA with both EID-CT and SR-PCD-CT prior to QCA. A total of 301 coronary segments were assessed for stenosis severity, with ≥50 % stenosis deemed significant. Image quality was graded using a 5-point scale. 

Results: No significant differences in percentage diameter stenosis (%DS) were found between imaging techniques (p = 0.20). Both EID-CT and SR-PCD-CT showed good agreement with QCA (AUC: PCD-CT 0.89, EID-CT 0.86). Specificity and NPV were high for both; sensitivity and PPV were moderate. SR-PCD-CT yielded higher image quality compared to EID-CT (p < 0.001).

Conclusions: In standard resolution mode, PCD-CT offers excellent image quality for quantifying coronary stenosis at comparable diagnostic accuracy compared to EID-CT

Background: Radial artery is the preferred access site in contemporary percutaneous coronary intervention (PCI). However, limited data exist regarding utilization pattern, safety, and long-term efficacy of transradial artery access (TRA) PCI in heavily calcified lesions using high-speed rotational atherectomy (HSRA).

Methods: All patients who underwent HSRA-PCI in Sweden between 2005 and 2016 were included. Outcomes were major adverse cardiac events (MACE, including death, myocardial infarction (MI) or target vessel revascularisation (TVR)), in-hospital bleeding and restenosis. Inverse probability of treatment weighting was used to adjust for the non-randomized access site selection.

Results: We included 1479 patients of whom 649 had TRA and 782 transfemoral artery access (TFA) HSRA-PCI. The rate of TRA increased significantly by 18% per year but remained lower in HSRA-PCI (60%) than in the overall PCI population (85%) in 2016. TRA was associated with comparable angiographic success but significantly lower risk for major (adjusted OR 0.16; 95% CI 0.05-0.47) or any in-hospital bleeding (adjusted OR 0.32; 95% CI 0.13-0.78). At one year, the adjusted risk for MACE (HR 0.87; 95% CI 0.67-1.13) and its individual components did not differ between TRA and TFA patients. The risk for restenosis did not significantly differ between TRA and TFA HSRA-PCI treated lesions (adjusted HR 0.92; 95% CI 0.46-1.81).

Conclusion: HSRA-PCI by TRA was associated with significantly lower risk for in-hospital bleeding and equivalent long-term efficacy when compared with TFA. Our data support the feasibility and superior safety profile of TRA in HSRA-PCI.

Objective: To evaluate the long-term efficacy of three currently available drug coated balloons (DCB) for the treat-ment of de-novo coronary lesions.

Methods: This was a retrospective analysis of prospectively collected data from the Swedish Coronary Angiogra-phy and Angioplasty Registry. Between 2009 and 2017, three currently available DCB brands used in the treat-ment of de novo lesions were included. Outcomes were clinically driven restenosis and target lesionthrombosis (TLT) (per device) and major adverse cardiac events (MACE) including death, myocardial infarctionor target vessel revascularization (per patient) at 4 years. Multivariable Cox regression models were used to ad-just for differences.

Results: We included 6715 lesions treated with DCBs, 4483 SeQuent® Please (S-DCB), 1071 IN.PACT Falcon (I-DCB) and 1161 Pantera® Lux (P-DCB), in 5670 patients. The mean DCB diameter was 2.4 mm. Bailout stentingoccurred in 6.7% of lesions. Angiographic success was 98.5%. The overall cumulative rate of restenosis was 5.5% (299 events). The risk for reported restenosis did not signifi-cantly differ between I-DCB vs S-DCB, adjusted hazard ratio (aHR) 0.96; 95% confidence interval (CI) 0.69–1.34,P-DCB vs S-DCB aHR 0.88; 95% CI 0.63–1.23 and I-DCB vs P-DCB aHR 1.10; 95% CI 0.72–1.68. The cumulative riskfor TLT was 0.8% in all three DCBs. The risk for MACE or individual components of MACE did not differ betweenthe three patient-groups.

Conclusion:In de novo coronary lesions, we found comparable long-term efficacy with three currently availableDCB brands. DCB angioplasty was feasible with low risk for long-term restenosis and TLT.

Skin injuries may occur when radiation doses to the skin exceed 2 Gy. This study aimed to measure changes in skin microcirculation in patients undergoing chronic total occlusion percutaneous coronary interventions (CTO-PCI). In 14 patients, peak skin dose (PSD) was estimated with radiographic films and skin microcirculation was assessed with laser speckle contrast imaging (LSCI), before, 1 day after the intervention, and 4–6 weeks later. The mean PSD was 1.8 ± 0.9 Gy. Peak skin microcirculation increased by 12% from 45 ± 6 PU before to 50 ± 9 PU 1 day after the intervention (p = 0.01), and returned to 46 ± 8 PU after 4–6 weeks (p = 0.15). There was no significant correlation between PSD and the change in perfusion, neither 1 day (r = −0.13, p = 0.69) nor 4–6 weeks after the intervention (r = 0.33, p = 0.35). These results suggest that there are no radiation-induced microvascular changes in the skin after CTO-PCI at skin doses below 2 Gy.