Percutaneous coronary intervention (PCI) remains the cornerstone of treatment for obstructive coronary artery disease, yet long-term outcomes continue to be influenced by mechanical factors such as suboptimal stent expansion, malapposition and vessel injury during deployment – particularly in complex lesion subsets.1,2 The limitations of conventional metallic drug-eluting stents (DES), including their inability to accommodate vessel growth and physiological movement, have prompted the development of novel implant technologies designed to restore more natural vascular behaviour.3,4
The DynamX Bioadaptor (Elixir Medical Corporation) represents an emerging class of ‘adaptive’ stent platforms that seek to overcome the rigid mechanical constraints of traditional DES. This next-generation coronary device is composed of a metallic scaffold with flexible helical connectors, designed to uncage the vessel after drug delivery and allow late positive remodelling. By decoupling radial support from chronic caging, the DynamX Bioadaptor may offer improved physiological compatibility and better healing response.4
Optical coherence tomography (OCT) has become a valuable imaging modality for assessing stent performance at high resolution, offering precise quantification of parameters such as acute lumen gain, device expansion, strut apposition and post-deployment vessel injury.5 Moreover, OCT is well suited to characterise lesion morphology and calcific burden pre-implantation and to evaluate device performance acutely in anatomically challenging lesions.6
This study aimed to evaluate the acute mechanical performance of the DynamX Bioadaptor in a contemporary clinical practice setting using OCT-based metrics. Specifically, we assessed lumen gain, device expansion, strut malapposition and edge dissection across a cohort of coronary lesions treated during routine PCI.
Methods
Study Design and Population
This retrospective study enrolled consecutive patients who underwent PCI with the DynamX Bioadaptor at Al Qassimi Hospital, Sharjah, the United Arab Emirates. The index procedures were performed between November 2020 and December 2024. Patients were eligible for inclusion if they received a DynamX Bioadaptor for the treatment of de novo coronary lesions and had both pre- and post-stenting OCT imaging available. Exclusion criteria included in-stent restenosis lesions, absence of either baseline or post-stenting OCT imaging and the presence of imaging artefacts that precluded accurate OCT analysis.
All patients provided written informed consent prior to the procedure. The study was authorised by the Ethics Committee of the Ministry of Health and Prevention in the United Arab Emirates (MOHAP/DXB-REC/J.F.M/No. 16/2025) and carried out in compliance with the principles of the Declaration of Helsinki.
Device Implantation Procedure
PCI was performed as per standard clinical practice. The transradial approach was preferred and converted to femoral access when necessary. Anticoagulation was achieved with an initial bolus of unfractionated heparin. Lesion preparation was according to the operator’s discretion, guided by baseline OCT findings. The DynamX Bioadaptor size was selected based on pre-stenting OCT imaging; device diameter selection adhered to a 1:1 sizing strategy relative to the distal reference measurements. The appropriate device length was determined to ensure optimal positioning within healthy tissue landing zones, identified either through external elastic lamina visualisation or by targeting regions with the largest luminal dimensions. Areas containing thin-cap fibroatheroma or lipid pools were deliberately avoided to prevent device edge placement in these high-risk regions. The device was deployed in accordance with standard interventional practice. Post-deployment optimisation was performed using a non-compliant balloon, guided by detailed post-procedural OCT analysis to ensure optimal device expansion and apposition.
Optical Coherence Tomography Acquisition and Analysis
OCT imaging was performed using the ILUMIEN OPTIS PCI Optimization System (Abbott Vascular). Automated pullbacks were conducted at a speed of 36 mm/s during contrast injection at a rate of 3–5 ml/s. Offline image analysis was carried out using Ultreon 2.0 OCT software (Abbott). All OCT measurements were performed by a blinded core analyst to ensure reproducibility.
Baseline Optical Coherence Tomography Analysis
Baseline OCT-pullback analysis was conducted at 2 mm intervals, encompassing the target coronary lesions and extending 4 mm proximally and distally beyond the lesion margins. This approach allowed for accurate calculation of the reference lumen area (RLA), which was defined as the mean of the two largest luminal areas within the 4-mm segments proximal and distal to the lesion. Lesion dimensions were quantified, including plaque length and minimal lumen diameter (MLD).
Plaques were categorised based on their compositional characteristics as follows: fibrous plaque displaying a homogeneous, high backscattering region attributed to the presence of compact smooth muscle cells; atherosclerotic lipid-rich plaque defined as heterogenous area with superficial high signal fibrous cap, followed by very low signal with irregular borders denoting lipid core; calcified plaque identified as a well-delineated, low-signal area with sharp borders; and ruptured plaque characterised by discontinuity of the fibrous cap, with or without an overlying thrombus. Thrombus was characterised as an intraluminal mass, either floating or adhering to the vessel wall (Figure 1 ).7–9 Further assessment of calcified plaques was performed using the OCT-based calcium volume index, assigning points as follows: 1 point for a maximum calcium arc >90°, 2 points for an arc >180°, 1 point for a maximum calcium thickness >0.5 mm, and 1 point for a calcium length >5 mm (Figure 1E).10
Post-implantation Optical Coherence Tomography Analysis
Offline analysis of the final OCT-pullback was conducted at 2 mm intervals and incorporated the implanted device as well as the adjacent reference segments, each extending 4 mm on both sides. The acute mechanical performance of the DynamX Bioadaptor was evaluated based on acute lumen gain, percentage of incomplete strut apposition (ISA), residual area stenosis and the presence of stent edge dissections.
Acute lumen gain was measured as the difference between minimal stent diameter (MSD) and preprocedural MLD, consistent with prior OCT studies.11 ISA was deemed significant when the distance between strut and luminal wall exceeded >300 µm, excluding regions adjacent to side branch exits. OCT studies and registry data identified gaps >300 µm, particularly with longitudinal extension >1 mm, as thresholds for clinically significant malapposition linked to very late stent thrombosis. The 300 µm cut-off is supported by evidence showing that larger inter-strut gaps can disturb flow and delay endothelial coverage, increasing the risk of stent thrombosis.1,12 ISA percentage was quantified as the ratio of malapposed struts to the total number of struts, expressed as a percentage. Residual area stenosis was computed using the formula: Residual area stenosis = [1 − minimum stent area (MSA)/RLA]. A stent edge dissection was described as any disruption of the vessel luminal surface extending to the media at the proximal or distal device edges characterised by the presence of an intimal flap.1,13
Statistical Analysis
Descriptive statistics include continuous variables displayed as mean ± SD; categorical variables are reported as frequencies and percentages.
Results
Table 1 shows patient demographics. There was a predominance of males and a high prevalence of cardiovascular risk factors, particularly dyslipidaemia and diabetes. Acute coronary syndrome (ACS) was the most common procedural indication, followed by primary PCI and stable angina.
Most procedures (96%) were performed via the radial artery approach. The left anterior descending (LAD) artery was the most frequently treated vessel (15 lesions, 51.7%), followed by the right coronary artery (eight lesions, 27.5%) and the left circumflex artery (six lesions, 20.6%). Lesions encompassed a spectrum of morphologies, including 13 lesions (44.8%) type B1 and 16 (55.2%) type B2/C American College of Cardiology/American Heart Association lesions. Specific lesion types included chronic total occlusions (7.0%), bifurcation lesions (13.8%) and ostial lesions (3.4%). Four bifurcation lesions were included in the study. Three were managed with a provisional stenting strategy followed by side-branch recrossing and balloon dilatation. One LAD/D1 bifurcation was treated using a T-and-protrusion technique; following predilatation, bifurcation reconstruction was performed with a DynamX 3.5 × 18 mm device in the LAD artery and a DynamX 2.75 × 14 mm device in D1. Procedural details are summarised in Table 2.
Baseline OCT analysis revealed a high prevalence of calcified coronary lesions, with over half of the plaques showing significant calcium burden; nearly one-third of lesions had a high OCT-based calcium volume index score (≥3). A considerable number of lesions demonstrated features of vulnerability, including plaque rupture and thrombus. Post-implantation OCT findings demonstrated adequate acute lumen gain and low residual area stenosis (Figure 2A, B, D and E). Strut apposition was nearly complete across most lesions, reflecting optimal device deployment (Figure 2B, E and F). Stent edge dissections were identified by OCT in four lesions, two of which required bailout stenting. Baseline and post-stenting OCT analysis results are summarised in Table 3.
Discussion
This study presents one of the first OCT-based assessments of the DynamX Bioadaptor system in a contemporary clinical practice setting. Our analysis, which included a heterogeneous cohort of coronary lesions, demonstrated favourable acute outcomes in terms of lumen gain, device expansion and apposition, even in heavily calcified and thrombotic coronary lesions.
Baseline OCT analysis revealed plaque rupture with overlying thrombus in approximately one-third of lesions, consistent with the clinical presentation; one-third of the bioadaptors were implanted in the context of primary PCI. Moreover, OCT imaging revealed that calcified plaques were the dominant morphology (55%), and 31% of lesions exhibited a high OCT-based calcium score (3 or 4) (Figure 1e).10 Such plaques are prone to under-expansion and are typically underrepresented in studies of novel stent technologies.14,15 Notably, 55% of the analysed lesions demonstrated a calcium thickness >0.30 mm – a threshold recently identified by Sato et al. as an independent predictor of suboptimal stent expansion.15
Post-stenting OCT imaging revealed an acute lumen gain of 1.37 ± 0.83 mm and an MSA of 5.54 ± 1.6 mm², exceeding the 4.5 mm² threshold previously identified as an independent predictor of adverse events in non–left main coronary lesions.16 These values fall within a similar range to those reported by Verheye et al. for the DynamX Bioadaptor (5.33 ± 1.6 mm²), despite the presence of more complex anatomical features in the present cohort.4 The achieved acute lumen gain is comparable to published series for conventional DES in similarly calcified lesion subsets.17
A residual area stenosis of 14.7 ± 9% was observed, indicating adequate device expansion in most treated lesions and remaining below the commonly accepted 20% threshold associated with favourable clinical outcomes. Although six devices exhibited a residual area stenosis between 20% and 30%, this range is generally considered acceptable in the context of heavily calcified lesions.15,18 Overall, the residual area stenosis observed in this population is comparable to that reported by Verheye et al. (13.93 ± 10.79%),4 and is in line with post-PCI residual area stenosis rates described for contemporary DES platforms such as SYNERGY (Boston Scientific) and XIENCE (Abbott) (approximately 15–20%) in routine clinical practice.19–21
The reported incomplete strut apposition (0.64 ± 1.34%) is substantially lower than that of first-generation DES (4–7%) and falls within similar range observed for second-generation DES, such as everolimus-eluting stents (0.4–1.6%).22–25 This favourable ISA profile likely reflects the adaptive design and radial strength of the DynamX Bioadaptor, enabling near-complete strut apposition, even in irregularly shaped or heavily calcified vessels (Figure 2 ). The clinical relevance of minimising ISA is highlighted by previous studies linking malapposition to adverse events, particularly late stent thrombosis.26
Four edge dissections were observed, of which two required bailout stenting. Although this appears relatively high (6.9%), it is consistent with edge-related complications in aggressive pre-dilatation or high-pressure post-dilatation strategies.27 In prior local experience, OCT-detected edge dissections occurred in 6.1% of DES (XIENCE) cases, with 1.2% requiring bailout, versus 15.1% in Absorb scaffolds (Abbott), with 6.5% requiring bailout. These data suggest that both device design and procedural technique may contribute.13 Importantly, the identification of these dissections by OCT enabled prompt management, likely reducing the risk of future adverse outcomes. This finding supports the critical role of intravascular imaging in optimising PCI results, especially with novel devices.3,27
Our procedural technique was characterised by meticulous lesion preparation, with pre-dilatation performed in 93% of cases and cutting balloon use in nearly half. This strategy reflects the significance of optimal lesion preparation before adaptive or dynamic scaffolds implantation, especially in calcified or lipid-rich plaques.28 Post-dilatation with non-compliant balloons was near-universal (97%). These practices are consistent with findings from the OCTIVUS and RENOVATE-COMPLEX-PCI studies, which emphasised the importance of thorough lesion preparation and post-implant optimisation for achieving adequate expansion and strut apposition.29,30
Our findings align with the 12-month clinical and imaging outcomes reported by Verheye et al., which demonstrated sustained device patency and favourable vascular healing with the DynamX Bioadaptor in a more stable patient cohort.4 However, our study included a higher-risk population; 29% undergoing primary PCI, and a greater prevalence of thrombotic and calcified lesions. Although follow-up was limited to acute outcomes, the favourable results in lesion expansion and strut apposition support the hypothesis that the DynamX bioadaptor confers distinct mechanical advantages in lesions with challenging anatomical features (Figure 2 ).
The device demonstrated acute performance comparable to that of second-generation DES, with the added advantage of preserving adaptive vessel motion through its uncaging segment design.1,19–25 Unlike earlier-generation bioresorbable scaffolds, which often exhibited suboptimal performance in complex lesions (Figure 2C ), the adaptive architecture of the DynamX system appears to enable superior mechanical integration, even in challenging settings such as calcified or thrombotic vessels.28
Conclusion
In a cohort with modest lesion complexity and a meaningful prevalence of calcification and ACS, the DynamX Bioadaptor demonstrated favourable acute mechanical performance as assessed by OCT. High acute lumen gain, low rates of malapposition, and effective device expansion support the technical feasibility of this novel bioadaptor technology in calcified and ACS settings. Overall, this study provides incremental, OCT-based acute performance data that add to the growing body of evidence supporting the early clinical applicability of the DynamX device. However, the absence of a comparator arm, limited sample size, single-centre retrospective design and lack of clinical endpoints limit the strength of the conclusions. Future prospective studies with serial imaging and clinical follow-up are warranted to confirm and validate these findings.
Clinical Perspective
- The DynamX Bioadaptor achieved significant lumen gain with low residual stenosis, suggesting effective device expansion in complex coronary lesions.
- The minimal incidence of malapposed struts highlights reliable strut apposition, which may translate into reduced thrombotic risk.
- Adequate expansion and apposition were achieved even in heavily calcified or ruptured plaques, supporting its use in such complex lesion subsets.