BVS IN STEMIDR.NILESH TAWADE

JASLOK HOSPITAL

Despite DES Is Established For The Revascularization in STEMI Some Questions

Remains :

The risk of late and very late stent thrombosisContinued neo-intimal tissue growth and neo-

atherosclerosis;Mal-apposition

Potential stent fractureIncomplete endothelialization

Vessel caging causing abnormal vasomotion.

.

The results of the ABSORB trial showed the efficacy and safety of a bioresorbable vascular scaffold (BVS)

BIO ABORBABLE SCAFFOLD

On Premise that scaffolding & drug are only required on a temporary basis following coronary interventions.

Several studies support this concept and indicate that there is no incremental clinical benefit of a permanent implant over time.

Use of Absorbable scaffold eliminates the presence of a mechanical restraint and offers potential of restoring natural vessel reactivity to NITRIC OXIDE .

Vascular Reparative therapy

The performance of Absorb is governed by three distinct phases: Revascularization Restoration these phases of Absorb performan- deliver

VRT Resorption.

Through the use of the imaging modality intravascular ultrasound (IVUS), data from the ABSORB Cohort B trial, reveals an increase in lumen area between 6 months and 2 years.

As Absorb resorbs, the vessel segment becomes unconstrained and there is the potential for lumen gain.

Advantage : BVSProvides stent scaffolding and radial strength properties as long as needed to ensure an open lumen – same as permanent stent

Leaves no stent behind (so no chronic inflammation, no long-term impact on local vasomotion)

No “Full metal jacket” makes later treatments of the same segment easier (e.g., surgical bypass) ; Better for younger patients

MRI / CT compatibility (allows non-invasive follow ups)

Potentially: no thrombosis and no need for prolonged antiplatelet therapy ???

Recently, a nonrandomized clinical trial comparing BVS and DES implantation in patients with acute

coronary syndrome (ACS) has shown that the use of BVS in this patient group is safe and has similar

outcomes to that of metal DES

Challenges of the scaffold implantation in ACS

Improper vessel sizing due to changes in the diameters of the vessel, which may appear smaller when flow is diminished or constricted by high

adrenergic stimulation. Adequate lesion preparation with predilations before scaffold implantation can potentially increase the risk of distal embolization if the lesion contains

a thrombus. Finally, the deployment technique with prolonged inflation time (stepwise

inflation of 2 atmospheres every 5 seconds up to the assumed pressure while maintaining the inflated balloon for 30 seconds) differs from the current

approach with metallic stents.

Experience in complex cases (bifurcation, ostial, CTO) is limited.

High strut thickness may lead to vessel injury, nonlaminar flow, platelet deposition, and poor deliverability.

Calcification or tortuosity are technically challenging which requires the proper bed preparation.

Regardless of lesion anatomy, pre-dilation is mandatory, direct stenting is not possible.

Duration of DAPT with BVS is unclear. Current Recommendations 3 Years

Current limitations and challenges

N=100Cohort 1 – 46 pts with UACohort 2 – 38 pts with NSTEMICohort 3 – 16 pts with STEMI

The procedural success was

97.9%. Pre-procedure

The intent-to-treat population comprises a total of 49 patients.

TIMI flow III was achieved in

91.7%

At the 30-day follow-up, target-lesion failure rate was 0%

BVS VS DES 290 pts / 1 yr

outcome

Device oriented endpoints (DOCE)

SIMILAR RATES OF DOCE AT 1 YR FOLLOW UP

NOT NEGLIGIBLE RATE OF SCAFFOLD

THROMBOSIS – IN EARLY PHASE

DAPT AND BVS OCT STUDY finding suggests that in areas of high shear stress (eg, vessel

curvatures, tortuosity, bifurcations)  neointimal cover of BVS struts might be incomplete even after 1 year.

Most interventionist would not feel safe stopping DAPT in the current scenario.

Some cases of a very late scaffold thrombosis after DAPT cessation

suggests that this dreadful complication is still present, even in the bioresorbable era, hence predisposing factors should be actively

investigated.

BVS vs DES STENT THROMBOSIS

high risk of MI and Definite/Probable stent thrombosis

SUMMARY

In the Present SCENARIO of PCI in acute MI Where there is a thrombogenic milieu Possibility of distal embolization (with Predilatation and ? Post dilatation )

The implantation of BVS in STEMI needs further studies and evaluation