Influence of additional ballooning with a dual wire balloon after a rotational atherectomy to expand drug-eluting stent for calcified lesions

A study of balloon type on calcified coronary lesion predilation: A finite element analysis

Calcified coronary lesions have been one of the more difficult types of lesion for interventional treatment, and angioplasty is required to break the calcification before stent implantation so that the stent can expand smoothly, however, it remains unclear which type of angioplasty is optimal for different calcified lesions. In this study, a finite element approach was used to model normal balloons, cutting balloons, and AngioSculpt balloons. In addition, calcified lesions of different degrees, thicknesses, and lengths were modeled according to Intravascular ultrasound (IVUS) calcification grade. The above three balloons were used to pretreat calcified lesions, and the brittle fracture module for calcification was used to detect fracture success, to facilitate virtual stent implantation after predilation. The simulation results showed that with a thickness of less than 0.3 mm, balloons were unable to deal with calcified plaques in lesions of less than 120°, for 180° calcified lesions the cutting balloon fractured the calcified material at 1.2 MPa, the AngioSculpt balloon produced multiple fractures at 0.8 MPa for 270° calcified plaques, but was unable to fracture calcified lesions with a thickness of 0.4 mm. Based on these results, we conclude that the length of the lesion did not affect calcification fracture, while the thickness of the lesion did. In calcified lesions of approximately 180°, the cutting balloon showed the best predilation results, while the AngioSculpt balloon was optimal for 270°. In annular calcification, all three balloons were unable to fracture the lesion.

Utility of a scoring balloon for a severely calcified lesion: bench test and finite element analysis

We aimed to investigate the effectiveness of a scoring balloon catheter in expanding a circumferentially calcified lesion compared to a conventional balloon catheter using an in vitro experiment setting and elucidate the underlying mechanisms of this ability using a finite element analysis. True efficacy of the scoring device and the underlying mechanisms for heavily calcified coronary lesions are unclear. We employed a Scoreflex scoring balloon catheter (OrbusNeich, Hong Kong, China). The ability of Scoreflex to dilate a calcified lesion was compared with a conventional balloon catheter using 3 different sized calcium tubes. The thickness of the calcium tubes were 2.0, 2.25, and 2.5 mm. The primary endpoints were the successful induction of cracks in the calcium tubes and the inflation pressures required for inducing cracks. The inflation pressure required for cracking the calcium tubes were consistently lower with Scoreflex (p < 0.05, Student t test). The finite element analysis revealed that the first principal stress applied to the calcified plaque was higher by at least threefold when applying the balloon catheter with scoring elements. A scoring balloon catheter can expand a calcified lesion with lower pressure than that of a conventional balloon. The finite element analysis revealed that the concentration of the stress observed in the outside of the calcified plaque just opposite to the scoring element is the underlying mechanism of the increased ability of Scoreflex to dilate the calcified lesion.