Innovative Entwicklungen – resorbierbare Scaffolds

Zusammenfassung

Die Implantation von medikamentefreisetzenden Stents (DES) gilt heute als Standard in der koronarinterventionellen Therapie, wenn eine mindestens 6-monatige duale Antiplättchentherapie (DAPT) zum Schutz vor Stentthrombosen gewährleistet werden kann. Trotz ihrer großen Effizienz in der Reduktion von Restenosierungen und notwendigen Re-Interventionen haben DES Nachteile: den möglichen chronischen mechanischen und inflammatorischen Gefäßwandreiz, seltener die Entwicklung von späten und sehr späten Stentthrombosen und gelegentlich die Entwicklung einer akzelerierten Neoarteriosklerose im DES.

Absorbierbare polymer- oder magnesiumbasierte Scaffolds haben eine temporäre Stützwirkung von ca. 3 Monaten und werden dann abgebaut. Damit erlauben sie dem Gefäß ein expansives Remodeling ohne permanenten mechanischen Gefäßwandreiz. Die bisher getesteten absorbierbaren Scaffolds haben in Kombination mit einer antiproliferativ wirkenden Medikamentenfreisetzung ähnlich gute Effizienzdaten zur Restenoselimitierung gezeigt wie permanente DES; die Patientenzahlen sind diesbezüglich allerdings bislang überschaubar. Scaffold-Thrombosen scheinen jedoch mit Blick auf die bisher verfügbaren Daten eher seltener aufzutreten als DES-Thrombosen, bei einer mindestens 6-monatigen Dauer der DAPT. Nachteil der polymerbasierten absorbierbaren Scaffolds ist deren geringere Radialkraft und Stabilität, die bei absorbierbaren Magnesium-Scaffolds besser und vergleichbar zu permanenten DES ist. Für die klinische Anwendung mit CE-Zertifizierung außerhalb von Studien ist lediglich der Everolimus-eluierende „Bioresorbable Vascular Scaffold“ (BVS) zugelassen, der mittlerweile bei mehreren tausend Patienten implantiert wurde.

Zukünftige Untersuchungsergebnisse mit absorbierbaren Scaffolds müssen deren bisherige vielversprechende Effizienz- und Sicherheitsdatenlage auch bei komplexeren Läsionsszenarien oder Patientensubpopulationen mit einer verkürzten DAPT-Dauer aufzeigen.

Abstract

Drug eluting stents (DES) are todayʼs standard of care for the interventional treatment of a coronary stenosis, if dual antiplatelet therapy (DAPT) can be maintained for at least six months. Despite a significant reduction in restenosis and reintervention rates DES have substantial limitations: they are permanent implants exposing a chronic mechanical and inflammatory stress to the vessel wall, are associated to especially late and very late DES thrombosis and develop an accelerated neoatherosclerosis within the DES.

Absorbable polymer or magnesium based scaffolds allow a temporary support of the vessel for about three months after which they are absorbed with a loss of radial strength, stability and mass. Thereby, an expansive vessel remodeling could develop without a permanent mechanical stress. Current absorbable scaffold technology is combined with the elution of an antiproliferative drug and has shown restenosis and reintervention rates similar to permanent DES. Scaffold thrombosis is a rare event and reported at lower rates compared to DES with the same DAPT regimen. Polymer-based scaffolds have a limited radial strength and stability compared to magnesium-based scaffolds which are comparable to DES. The “Bioresorbable Vascular Scaffold” (BVS) is the only scaffold which is CE-marked as of today and has been implanted also outside of clinical trials in several thousand patients.

In future trials, the promising efficacy and safety results of bioabsorbable scaffolds have to be repeated in more complex lesion scenarios and patient subsets addressing also the potential for a shortened DAPT duration.

Schlüsselwörter

medikamentefreisetzende Stents - absorbierbare polymerbasierte Scaffolds - absorbierbare metallische Scaffolds - Restenose - Stentthrombose - Scaffold-Thrombose

Key words

drug eluting stents - absorbable polymer-based scaffolds - absorbable metal-based scaffolds - restenosis - stent thrombosis - scaffold thrombosis

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