Assessment of the hemodynamic characteristics of Absorb BVS in a porcine coronary artery model

Prognostic value of quantitative flow ratio in patients with coronary heart disease after percutaneous coronary intervention therapy: a meta-analysis

Background

Coronary atherosclerotic heart disease is one of the most serious health and life-threatening diseases. There is no doubt that despite the increasing number of assessment methods used clinically, the prognosis assessment is still not ideal, and newer assessment methods are needed.

Objective

To investigate the predictive value of quantitative flow ratio (QFR) for adverse events (vessel-oriented composite endpoint events/target lesion failure) in patients after percutaneous coronary intervention (PCI).

Method

Eight studies involving 4,173 patients (5,688 vascular lesions) were included. These are studies on the relationship between QFR values and prognosis of adverse cardiac events after PCI. This meta-analysis was performed after quality assessment and data extraction of clinical trials data that met the inclusion criteria.

Result

Each of the eight studies described the cut-off values for the best predictive ability of post-PCI QFR and the hazard ratio (HR) between QFR values and adverse events, respectively. The pooled HR of these studies was 4.72 (95% CI: 3.29-6.75). Concurrently, lower post-PCI QFR values were associated with the occurrence of individual clinical events (cardiac death/myocardial infarction/target vessel revascularization), with relative risk values of 6.51 (95% CI: 4.96-8.53), 4.83 (95% CI: 3.08-7.57), and 4.21 (95% CI: 2.66-6.68), respectively.

Conclusion

QFR may have great potential in the assessment of prognosis. It is necessary to measure QFR value after PCI. A lower QFR value after PCI was an important predictor for experiencing adverse events.

Bioresorbable vascular scaffolds versus everolimus-eluting stents: a biomechanical analysis of the ABSORB III Imaging substudy

AIMS

The Absorb bioresorbable vascular scaffold (BVS) has high rates of target lesion failure (TLF) at three years. Low wall shear stress (WSS) promotes several mechanisms related to device TLF. We investigated the impact of BVS compared to XIENCE V (XV) on coronary WSS after device deployment.

METHODS AND RESULTS

In the prospective, randomised, controlled ABSORB III Imaging study (BVS [n=77] or XV [n=36]), computational fluid dynamics were performed on fused angiographic and intravascular ultrasound (IVUS) images of post-implanted vessels. Low WSS was defined as <1 Pa. There were no differences in demographics, clinical risks, angiographic reference vessel diameter or IVUS minimal lumen diameter between BVS and XV patients. A greater proportion of vessels treated with BVS compared to XV demonstrated low WSS across the whole device (BVS: 17/77 [22%] vs XV: 2/36 [6%], p<0.029). Compared to XV, BVS demonstrated lower median circumferential WSS (1.73 vs 2.21 Pa; p=0.036), outer curvature WSS (p=0.026), and inner curvature WSS (p=0.038). Similarly, BVS had lower proximal third WSS (p=0.024), middle third WSS (p=0.047) and distal third WSS (p=0.028) when compared to XV. In a univariable logistic regression analysis, patients who received BVS were 4.8 times more likely to demonstrate low WSS across the scaffold/stent when compared to XV patients. Importantly, in a multivariable linear regression model, hypertension (beta: 0.186, p=0.023), lower contrast frame count velocity (beta: -0.411, p<0.001), lower post-stent residual plaque burden (beta: -0.338, p<0.001), lower % underexpanded frames (beta: -0.170, p=0.033) and BVS deployment (beta: 0.251, p=0.002) remained independently associated with a greater percentage of stented coronary vessel areas exposed to low WSS.

CONCLUSIONS

In this randomised controlled study, the Absorb BVS was 4.8 times more likely than the XV metallic stent to demonstrate low WSS. BVS implantation, lower blood velocity and lower residual post-stent plaque burden were independently associated with greater area of low WSS.

Procedural microvascular activation in long lesions treated with bioresorbable vascular scaffolds or everolimus-eluting stents: the PROACTIVE trial

AIMS

Significant platelet activation after long stented coronary segments has been associated with periprocedural microvascular impairment and myonecrosis. In long lesions treated either with an everolimus-eluting bioresorbable vascular scaffold (BVS) or an everolimus-eluting stent (EES), we aimed to investigate (a) procedure-related microvascular impairment, and (b) the relationship of platelet activation with microvascular function and related myonecrosis.

METHODS AND RESULTS

Patients (n=66) undergoing elective percutaneous coronary intervention (PCI) in long lesions were randomised 1:1 to either BVS or EES. The primary endpoint was the difference between groups in changes of pressure-derived corrected index of microvascular resistance (cIMR) after PCI. Periprocedural myonecrosis was assessed by high-sensitivity cardiac troponin T (hs-cTnT), platelet reactivity by high-sensitivity adenosine diphosphate (hs-ADP)-induced platelet reactivity with the Multiplate Analyzer. Post-dilatation was more frequent in the BVS group, with consequent longer procedure time. A significant difference was observed between the two groups in the primary endpoint of ΔcIMR (p=0.04). hs-ADP was not different between the groups at different time points. hs-cTnT significantly increased after PCI, without difference between the groups.

CONCLUSIONS

In long lesions, BVS implantation is associated with significant acute reduction in IMR as compared with EES, with no significant interaction with platelet reactivity or periprocedural myonecrosis.

Hemodynamic analysis of a novel bioresorbable scaffold in porcine coronary artery model

BACKGROUND

The shear stress distribution assessment can provide useful insights for the hemodynamic performance of the implanted stent/scaffold. Our aim was to investigate the effect of a novel bioresorbable scaffold, Mirage on local hemodynamics in animal models.

METHOD

The main epicardial coronary arteries of 7 healthy mini-pigs were implanted with 11 Mirage Microfiber sirolimus-eluting Bioresorbable Scaffolds (MMSES). Optical coherence tomography (OCT) was performed post scaffold implantation and the obtained images were fused with angiographic data to reconstruct the coronary artery anatomy. Blood flow simulation was performed and Endothelial Shear Stress(ESS) distribution was estimated for each of the 11 scaffolds. ESS data were extracted in each circumferential 5-degree subunit of each cross-section in the scaffolded segment. The generalized linear mixed-effect analysis was implemented for the comparison of ESS in two scaffold groups; 150-µm strut thickness MMSES and 125-µm strut thickness MMSES.

RESULTS

ESS was significantly higher in MMSES (150 µm) [0.85(0.49-1.40) Pa], compared to MMSES (125 µm) [0.68(0.35-1.18) Pa]. Both MMSES (150 µm) and MMSES (125 µm) revealed low recirculation zone percentages per luminal surface area [3.17% ± 1.97% in MMSES (150 µm), 2.71% ± 1.32% in MMSES (125 µm)].

CONCLUSION

Thinner strut Mirage scaffolds induced lower shear stress due to the small size vessels treated as compared to the thick strut version of the Mirage which was implanted in relatively bigger size vessels. Vessel size should be taken into account in planning BRS implantation. Small vessels may not get benefit from BRS implantation even with a streamlined strut profile. This pilot study warrants comparative assessment with commercially available bioresorbable scaffolds.

Transradial experience with bioresorbable vascular scaffolds: A case-matched study with metallic drug-eluting stents

BACKGROUND

Whether polymeric bioresorbable vascular scaffolds (BVS) implantation with transradial approach is feasible and safe is unknown. We compared the feasibility and safety of the transradial approach for BVS delivery with metallic drug-eluting stents (DES).

METHODS

We identified 118 consecutive patients who underwent BVS implantation and we compared 30-days and 1-year results with 118 matched patients with DES. Patients were matched for age, sex, risk factors and clinical indication.

RESULTS

Rates of transradial approach were 98% in the BVS group vs 95% in the DES group (P = 0.16) with 5Fr used in 38% and 32% (P = 0.34), respectively. The number of stents was similar in both groups, 2.6 ± 1.5 vs 2.4 ± 1.3 (P = 0.23). Although maximal pressure for stent deployment was identical in both groups (16 ± 3 atm), more lesions were pre-dilated (83% vs 52%, P < 0.001) and post-dilated (71% vs 33%, P < 0.001) in the BVS group. Contrast volume (217 ± 97 vs 175 ± 108 ml, P < 0.001), fluoroscopy time (16 [10-23] vs 13 [8-21] min, P = 0.04) and procedure duration (65 ± 31 vs 56 ± 47 min, P = 0.045) were significantly higher in the BVS group. Major adverse cardiac events, including death, myocardial infarction and target vessel revascularization remained similar in both groups, 1.7% vs 0.8% (P = 0.56) at 30 days and 10% vs 8.5% (P = 0.66) at 1 year. At 1 year, stent thrombosis occurred in 2 (1.7%) patients in the BVS group and 1 (0.8%) patient in the DES group (P = 0.56).

CONCLUSION

The use of transradial approach for BVS compared to DES implantation was feasible and safe in all-comers, although BVS implantation included more technical challenges. Outcomes up to 1-year remained comparable in both groups.

Patient-Specific Modeling of Stented Coronary Arteries Reconstructed from Optical Coherence Tomography: Towards a Widespread Clinical Use of Fluid Dynamics Analyses

The recent widespread application of optical coherence tomography (OCT) in interventional cardiology has improved patient-specific modeling of stented coronary arteries for the investigation of local hemodynamics. In this review, the workflow for the creation of fluid dynamics models of stented coronary arteries from OCT images is presented. The algorithms for lumen contours and stent strut detection from OCT as well as the reconstruction methods of stented geometries are discussed. Furthermore, the state of the art of studies that investigate the hemodynamics of OCT-based stented coronary artery geometries is reported. Although those studies analyzed few patient-specific cases, the application of the current reconstruction methods of stented geometries to large populations is possible. However, the improvement of these methods and the reduction of the time needed for the entire modeling process are crucial for a widespread clinical use of the OCT-based models and future in silico clinical trials.