Long-term vascular function in CTO recanalization: A randomized clinical trial of ticagrelor vs. clopidogrel

BACKGROUND

Coronary vascular function of a chronic coronary total occlusion (CTO) immediately after recanalization is known to be poor and to be partially improved by pre-treatment with loading dose of ticagrelor vs. clopidogrel. It is unknown if this vascular dysfunction is maintained at long-term follow-up and may be improved by 1-year dual antiplatelet therapy (DAPT).

METHODS

The TIGER is a prospective, open-label, two parallel-group controlled clinical trial, which 1:1 randomized 50 CTO patients to pre-PCI loading dose and subsequent 1-year DAPT with ticagrelor vs. clopidogrel. Coronary blood flow (CBF) under stepwise adenosine infusion was assessed after drug loading dose and at follow-up and compared between the two drug groups, adjusting for time of follow-up.

RESULTS

Out of 50 patients with index CBF evaluation, 38 (76%) patients underwent angiographic follow-up (23 and 15 at 1 and 3-year, respectively) and Doppler data was available in 35 (70%). A high CBF area under the curve (AUC), already observed after loading dose in ticagrelor vs. clopidogrel group (p = 0.027), was maintained at follow-up (AUC 34815.22 ± 24,206.06 vs. AUC 22712.47 ± 13,768.95; p = 0.071). Specifically, whereas high ticagrelor loading dose-related CBF was sustained at follow-up (p = 0.933), clopidogrel loading dose-related CBF increased at follow-up (p = 0.039).

CONCLUSION

The TIGER trial showed that DAPT with ticagrelor maintained a non-significantly higher CBF in a recanalized CTO as compared to clopidogrel, whose treated patients exhibit a lower CBF immediately after PCI with a significant increase at follow-up. The clinical value of such sustained high coronary flow should be evaluated in a larger group of patients.

CLINICAL TRIAL REGISTRATION

https://clinicaltrials.gov/ct2/show/NCT02211066 (ClinicalTrials.gov number NCT02211066).

Is the Dream of Vascular Restoration Still Alive? A Case of 7 Years, Follow-Up After Bioresorbable Vascular Scaffold Implantation

BACKGROUND

Bioresorbable scaffold (BRS) have the aim to combine short-term radial force by vessel scaffold (which should dissolve after few months), with drug eluting capability. It has been hypothesized that complete resorption would result in restoration of vasomotion, reduction in angina and reduction of restenosis.

CASE PRESENTATION

We report a case of 7 years angiographic follow up after DESolve Novolimus eluting Bioresorbable Coronary Scaffold System implantation.

CONCLUSION

The invasive control showed persistence of scaffold patency and evidence of restored vascular motility by the growing in vessel diameter at QCA control after nitrates administration.

Bioresorbable Vascular Scaffolds-Dead End or Still a Rough Diamond?

Percutaneous coronary interventions with stent-based restorations of vessel patency have become the gold standard in the treatment of acute coronary states. Bioresorbable vascular scaffolds (BVS) have been designed to combine the efficiency of drug-eluting stents (DES) at the time of implantation and the advantages of a lack of foreign body afterwards. Complete resolution of the scaffold was intended to enable the restoration of vasomotor function and reduce the risk of device thrombosis. While early reports demonstrated superiority of BVS over DES, larger-scale application and longer observation exposed major concerns about their use, including lower radial strength and higher risk of thrombosis resulting in higher rate of major adverse cardiac events. Further focus on procedural details and research on the second generation of BVS with novel properties did not allow to unequivocally challenge position of DES. Nevertheless, BVS still have a chance to present superiority in distinctive indications. This review presents an outlook on the available first and second generation BVS and a summary of results of clinical trials on their use. It discusses explanations for unfavorable outcomes, proposed enhancement techniques and a potential niche for the use of BVS.

Multimodality intravascular imaging of bioresorbable vascular scaffolds implanted in vein grafts

Introduction

There are no data presenting a serial assessment of vein graft healing after bioresorbable vascular scaffold (BVS) implantation at long-term follow-up.

Aim

To describe ABSORB BVS healing in vein grafts by optical coherence tomography (OCT) and high-definition intravascular imaging (HD-IVUS) at long-term follow-up.

Material and methods: The study group consisted of 6 patients. The first patient had serial OCT assessment of BVS implanted in the saphenous vein grafts (SVG) at baseline and at 3-, 6-, 18-month follow-up and the second patient had OCT assessment of BVS implanted in the SVG at baseline and 24-, 48-month follow-up. The second and the third patients had OCT and HD-IVUS imaging at baseline and 48-month follow-up. The last 3 patients had OCT imaging of BVS implanted in the native coronary artery at 48-month follow-up.

Results

There were no differences in neointimal hyperplasia after BVS implantation between each time point. However, complete scaffold coverage was observed only 48 months after implantation. Out of 202 analyzed scaffold struts, there were 67 (33%) black boxes detectable at 48-month follow-up. HD-IVUS presented plaque burden up to 67% at the segment of BVS implantation at 48-months follow-up. There was a difference in neointimal hyperplasia thickness (1.27 (0.953–1.696) vs. 0.757 (0.633–0.848), p < 0.001) between a native coronary artery and BVS scaffolds at 48-month follow-up.

Conclusions

Bioresorbable vascular scaffold implanted in SVG characterized moderate neointimal hyperplasia as excessive as compared to native coronary arteries at long-term follow-up. The complete scaffold coverage was observed only 48 months after implantation.