Clinical, angiographic and procedural characteristics of longitudinal stent deformation

In-stent restenosis and longitudinal stent deformation: a case report

Background

Longitudinal stent deformation (LSD) is an infrequent complication of percutaneous coronary intervention (PCI), and it may lead to catastrophic clinical outcomes. However, reports of cardiac adverse events associated with LSD are rare.

Case presentation

A 55-year-old man with chest pain was treated for a severe left anterior descending branch (LAD)-diagonal 1 (D1) bifurcation lesion by PCI with two stents in the proximal LAD. LSD occurred during the withdrawal of the trapped D1 wire. High-pressure balloon dilatation was performed in the deformed stent, and the end-angiographic appearance was acceptable, but no additional corrective measures were implemented. Ten months later, the patient represented with acute coronary syndrome. Severe in-stent restenosis (ISR) had suboccluded the proximal LAD, and optical coherence tomography (OCT) visualized multilayered stent struts protruding into the lumen at the compressed segment of the stent. Following complete apposition with balloon dilation, a drug-coated balloon (DCB) was used to avoid an additional permanent metallic layer. He remained angina free, and the angiographic result demonstrated no residual stenosis at the six-month follow-up. To our knowledge, this case demonstrates the first report of ISR triggered by LSD in patients treated with DCBs under the guidance of OCT.

Conclusions

The current report underscores the importance of awareness of LSD, and OCT seems to be the preferred modality to confirm complete apposition. If left without performing additional corrective measures, LSD may be associated with a risk of ISR. Complete apposition with balloon dilation followed by a DCB is a feasible treatment option.

Thin and crush: The new mantra in left main stenting?

Complex bifurcations have been suggested to be better approached by a planned double stent technique; however, recent randomized trials have shown better outcomes of provisional compared to planned two-stent strategy, in terms of both short-term efficacy and safety. In left main (LM) bifurcations, double kissing (DK)-Crush has demonstrated its superiority over Culotte and provisional-T in terms of restenosis and stent thrombosis, gaining respect as one of the most performant techniques for bifurcations stenting. On the other hand, the Nano-Crush technique has recently become part of the repertoire of double stenting techniques, providing evidence that the use of ultrathin strut stents and very minimal crush would be beneficial for both the physiological and rheological properties of the complex bifurcations, even in LM scenario, leading to a lower rate of thrombosis and restenosis at both side branch and true carina. Finally, the newest generation of ultrathin strut stents are gaining a reputation for its safe and effective use in LM treatment thanks to improved design with increased expansion rate capable of LM treatment up to 5-6 mm diameter. The modern crush techniques, such as DK-Crush and Nano-Crush, are providing excellent results on mid and long-term follow up, suggesting that minimal crushing obtained using ultra-thin stents is a good way to obtain surgical-like outcomes in the treatment of complex LM bifurcation disease.

Complex coronary bifurcation treatment by a novel stenting technique: Bench test, fluid dynamic study and clinical outcomes

OBJECTIVES

We assess the mid-term outcomes of ultrathin biodegradable polymer double stenting using a very minimal crushing (Nano-Crush) technique in large complex coronary bifurcation.

BACKGROUND

Complex bifurcations have been suggested to be better approached by a planned double stent technique.

METHODS

Two hundred and five consecutive patients (107 males and 98 females) referred for large complex coronary bifurcation percutaneous coronary interventions were enrolled. The technique was also evaluated by both a bench test with a silicon tubes phantom resembling a coronary bifurcation and a computed fluid dynamic (CFD) analysis.

RESULTS

Left main bifurcation accounted for 40.9% of cases (84 patients). Mean angles between main branch (MB) and side branch (SB) were 63.6 ± 21.3°. SB intravascular ultrasound-calculated MSA was 5.6 ± 1.5 mm2 . Clinical follow-up was available for 100% of patients and at a mean follow-up of 16.2 ± 6.7 months 8 deaths, all due to cardiovascular reason, (3.9%, 4 patients for stroke, two for heart failure, one after surgical aortic valve substitution, and one after acute massive pulmonary embolism) and no presumptive stent thrombosis or target vessel induced ischemia were observed. Angiographic follow-up was available in 108 patients (52.7%) and showed a very low significant restenosis (5 patients, 4.6%). Bench study and CFD evaluation suggested a complete coverage of the SB ostium with a very high strut-free area at the SB.

CONCLUSIONS

The revascularization of complex large coronary bifurcation disease using the Nano-crush technique appeared promising thanks to the favorable fluid dynamic profile, complete coverage of the SD ostium, and very small metal amount at the carina.

A catastrophic nightmare of the interventional cardiologist: Iatrogenic left main artery dissection and longitudinal stent deformation

Iatrogenic left main coronary artery dissection is a rare but potentially life-threatening complication of invasive coronary procedures. The newer generation drug eluting stents have shown a greater safety and efficacy compared to first generation drug eluting stents. We report a 60-year-old woman with iatrogenic left main coronary artery dissection who failed bailout stenting and underwent coronary artery bypass grafting. The strategy for managing left main coronary artery dissection is variable and depends upon the mechanism, the comorbidities of the patient and degree of hemodynamic stability. Longitudinal stent deformation is a rarely encountered complication but can be seen in complex lesions such as ostial, bifurcation and left main coronary artery lesions. The interventionists must be aware of this complication.

The potential hazard of a non-slip element balloon causing distal longitudinal stent deformation: the first clinical experience and in vitro assessment

BACKGROUND

A new complication, longitudinal stent deformation (LSD), is increasingly reported with recent intracoronary stent designs. There have been experiences of unusual cases of distal LSD caused by entrapment of a Lacrosse® non-slip element (NSE) balloon (Goodman Co., Ltd., Nagoya, Japan), which has three flexible nylon elements to prevent slippage. Accordingly, the aim of this study is to report the clinical experience of distal LSD caused by the NSE in the documented center and to investigate the incidence and mechanisms involved.

METHODS

Coronary intervention cases were retrospectively reviewed using the NSE balloon in hospital between May 2014 and June 2017. In bench testing, distal LSD was reproduced in a silicon tube model to identify its mechanism.

RESULTS

A total of 95 patients with 107 lesions underwent coronary interventions with NSE. Of these, 72 lesions (12 de-novo lesions and 60 in-stent restenosis) were treated using in-stent dilatation. Two distal LSD cases occurred, representing an incidence of 2.78% (2/72) among all procedures; 16.7% (2/12) of the de-novo lesions developed LSD. In vitro experimentation allowed indentification of the mechanisms involved and bailout strategies.

CONCLUSIONS

This is the first study to evaluate NSE balloon catheter entrapment complicated by distal LSD in which reconstruction of the deformed stent and retrieval of the NSE could be achieved successfully. There is a potential hazard for distal LSD during post-dilatation using the NSE balloon due to its structural characteristics. Careful assessment is needed to prevent this complication.

Impact of post-dilatation on longitudinal stent elongation: An in vitro study

OBJECTIVES

To evaluate whether balloon inflation for post-dilatation causes longitudinal stent deformation (LSD).

METHODS AND RESULTS

Two stents, sized 2.5mm×28mm and 3.5mm×28mm (Nobori^®, biodegradable polymer biolimus-eluting stent; Ultimaster^®, biodegradable polymer sirolimus-eluting stent; Terumo Co., Tokyo, Japan), were deployed at nominal pressure in straight and tapered silicon vessel models. Then, post-dilatation was performed in two ways: dilatation from the distal (D-P group) or proximal (P-D group) side of the stent. Microscopic findings showed that the stents were elongated during every step of the procedure regardless of the post-dilatation method and type of vessel model. The D-P group showed linear elongation during each step of post-dilatation (straight model: 28.7±0.3mm vs. 29.9±0.3mm, p=0.002; tapered model: 28.0±0.1mm vs. 29.9±0.1mm, p<0.001). In contrast, in the P-D group, the most significant change was observed in the first step of post-dilatation and only slight changes were observed thereafter (straight model: 28.6±0.1mm vs. 29.5±0.1mm, p<0.001; tapered model: 28.2±0.1mm vs. 29.5±0.1mm, p<0.001). Optical frequency domain imaging analysis showed that the frequency of stent strut malapposition was positively correlated with the percentage change in stent length (r=0.74, p<0.0001).

CONCLUSION

LSD was observed during every step of post-dilatation in both the straight and tapered vessel models. However, some differences were observed between the D-P and P-D groups. Minimizing stent strut malapposition may reduce the risk of LSD.

Complex coronary bifurcation revascularization by means of very minimal crushing and ultrathin biodegradable polymer DES: Feasibility and 1-year outcomes of the "Nano-crush" technique

AIM

To assess feasibility and 1-year outcomes of ultrathin biodegradable polymer double stenting using a very minimal crushing (nano-crush technique) in a series of patients with large (≥2.5mm) complex coronary bifurcation.

METHODS

From January 2015 to June 2016, patients referred for large (≥2.5mm) complex coronary bifurcation percutaneous coronary interventions (PCI) were enrolled to receive Orsiro (Biotronik Inc., Bulack, Switzerland) double stenting using a very minimal crush technique (nano-crush). Per our institutional protocol, follow-up was conducted by physical examination at 1, 6, 12month and yearly whereas angiographic control was eventually scheduled at 6-8months on the basis of symptoms recurrence or/and positive induced ischemia tests.

RESULTS

Fifty-two patients (15 females mean age 77.2±6.2years) were enrolled. Mean angles between main branch and side branch were 63.6±21.3°. The mean diameter and length of implanted stents were 3.8±0.4mm and 27.1±8.7mm in main branch and 2.8±0.3mm and 22.1±.7.1mm in side branch. Immediate success was 100%. Clinical follow-up was available for 100% of patients: at a mean follow-up of 12.0±2.6months, no patient death, or acute myocardial infarction or target vessel revascularization were observed. Angiographic follow-up was available in 25/52 patients (48%) at a mean time from the procedure of 7.2±0.5months and showed no significant angiographic restenosis.

CONCLUSIONS

The revascularization of complex large (≥2.5mm) coronary bifurcation disease using the nano-crush technique and the ultrathin polymer biodegradable stent appeared feasible in our small study with promising 1year outcomes.