Stiller B, Zartner P, Dähnert I, Haas NA, Schubert S, Kanaan M, Berger F, Ewert P, Schmoor C, Grohmann J.
Catheter Cardiovasc Interv. 2022 Apr;99(5):1529-1537. doi: 10.1002/ccd.30133. Epub 2022 Feb 16.
PMID: 35170186 Clinical Trial.
Take Home Points:
- The Osypka BabyStent is a 15mm long cobalt chromium stent, premounted on a 6mm balloon and inserted through a 4 French sheath.
- The stent can be expanded to 10-12mm and with further dilation the locking mechanism of the hook and eye connections opens allowing for further dilation without the need to fracture the stent.
- The stent was successfully implanted in all patients without access site complications.
Commentary from Dr. Konstantin Averin (New York), catheterization section editor of Pediatric Cardiology Journal Watch:
Balloon expandable stents (BES) are the mainstay of therapy for many forms of congenital heart disease. In smaller patients, BES use can be limited by the expansion potential of appropriate profile stents. The “holy grail” for congenital interventional cardiologist is a balloon expandable stent that has a low delivery profile, can be implanted at small diameters, and can easily be expanded to adult sizes. In this report, the authors describe the results of a prospective, interventional, open, single-arm, multicenter study from six sites in Germany from 9/2015 to 10/2018 using the breakable Osypka BabyStent (OBS) for treatment of coarctation of the aorta (CoA).
OBS is a low profile, 15mm long cobalt-chromium stent, premounted on 6mm balloon and inserted via a 4Fr sheath over a 0.018” wire. The stent easily expands to 10-12mm and after this the locking mechanism of the hook and eye connections opens allowing for further dilation without the need to fracture the stent – see Figure below.
Inclusion criteria were BW > 1.8kg, age < 24 month at time of procedure and isolated aortic or aortic arch obstruction (meeting criteria for stent implant at time of catheterization) deemed high-risk for surgical intervention. Thirty-one patients were screened and subsequently underwent cardiac catheterization; 12 of these did not meet inclusion criteria (10 due to successful balloon dilation and 2 due to lack of consent) – this left 19 patients (median weight 5.6 kg [2.4-8.4] and age 112 days [7-539]). All stents were successfully implanted with the primary endpoint (inner lumen expansion by >50% of baseline diameter) achieved in 15/19 (79%). Most patients required reintervention at 12 months post-stent implant (2 surgical revision and 13 balloon dilation, with 4 requiring a second re-dilation). All patients were alive at 12 month follow up. The two patients requiring surgical revision were due to a post-stent aneurysm at a surgical suture line (implanted 13 days post-surgery) and 1 after stent implant allowed for myocardial recovery with residual gradient. There were no access complications.
The authors describe the successful use of a new stent design that facilitates stent therapy in infants in small children. While not adult capable, these stents convert the relatively chaotic and uncontrolled process of stent fracture into one that is controlled and likely carries less morbidity. Whether this stent proves to be the “holy grail” of stent therapy is not yet clear, but it is certainly an important step-forward in stent design for treatment of congenital heart disease.