Comparative Computed Flow Dynamic Analysis of Different Optimization Techniques in Left Main Either Provisional or Culotte Stenting

Residence time in complex left main bifurcation disease after stenting

BACKGROUND

Data regarding the mean resident time (RT) after left main (LM) bifurcation stenting are scant. In the present study we performed a patient-specific computational fluid dynamic (CFD) analysis to investigate the different post-stenting mean RT values in LM patients treated with single-or double stenting techniques.

METHODS

Patients were identified after reviewing the local Optical Coherence Tomography (OCT) scans database. Overall, 27 patients (mean age 65.5 ± 12.4, 21 males) [10 patients treated with provisional cross-over stenting, 7 with the double kissing crush (DK crush) and 10 with the nano-inverted T (NIT) technique, respectively] with isolated and significant LM bifurcation disease were analyzed.

RESULTS

After LM bifurcation stenting, the NIT showed a higher averages WSS values at all bifurcation sites compared to DK crush and provisional cross-over stenting. Moreover, the mean RT resulted lower after NIT compared to provisional or DK crush. During the diastolic phase, the average RT of the entire LM bifurcation was 0.46 s, 0.38 s and 0.33 s after using the provisional stenting, DK crush and NIT, respectively. Moreover, the average RT in the LM bifurcation decreased by 17.1 % using the DK crush and by 28.2 % using the NIT compared to the Provisional.

CONCLUSION

The present OCT-derived CFD analysis revealed that, in patients with complex bifurcation LM disease, the provisional approach resulted in lower WSS values, while double stenting techniques, especially the NIT technique, resulted in a marked reduction of average RT compared to the provisional approach.

CONDENSED ABSTRACT

In the present study we performed a patient-specific Optical coherence tomography (OCT)-based computational fluid dynamic (CFD) analysis to investigate the different post-stenting mean RT values in 27 patients treated with provisional cross-over stenting, DK crush and Nano-inverted-T (NIT) stenting. The NIT showed a higher averages WSS values at all bifurcation sites compared to DK crush and Provisional. The mean RT resulted lower in NIT compared to Provisional or DK crush. During the entire diastolic phase, the average RT of the entire LM bifurcation was 0.46 s, 0.38 s and 0.33 s after using the provisional stenting, DK crush and NIT, respectively. Moreover, the average RT in the entire LM bifurcation decreased by 17.1 % using the DK crush and by 28.2 % using the NIT compared to the Provisional.

Twelve-month clinical outcomes of "nano-crush technique" for the treatment of bifurcation lesions using ultra-thin (60 µm) sirolimus-eluting coronary stents

BACKGROUND

Provisional stenting is preferred for bifurcation lesion; however, certain anatomical substrate does require two stents as a part of dedicated stent technique. Here, the present study evaluated outcomes of ultra-thin (60 µm) Supra family sirolimus-eluting stent (SES) (Sahajanand Medical Technologies Limited, Surat, India) for dedicated bifurcation lesions using nano-crush technique at 12 months angiographic follow-up.

METHODS

This was prospective, single-center observational study which enrolled patients with de novo bifurcation lesion and underwent angioplasty with Supra family SES using nano-crush technique at a tertiary care center in India, between March-2017 and February-2019. Primary endpoint at 12 months was target lesion failure (TLF), a composite of cardiac death, target vessel myocardial infarction (TV-MI), and clinically driven target lesion revascularization (CD-TLR). Secondary endpoints included patient-oriented composite endpoint (POCE), all-cause death, any revascularization, clinically driven target vessel revascularization, stent thrombosis, periprocedural and spontaneous MI, and device failure.

RESULTS

The study enrolled total 63 patients with a mean age of 62.5±4.9 years and had male dominance (89%). Left main (LM) bifurcation and non-LM bifurcation were observed in 21 (33%) and 42 (67%) patients, respectively. Total 50 (80%) patients had Medina class- 1,1,1. At 12 months, TLF occurred in 4 (6%) patients which included one cardiac death (1.5%), two (3.0%) TV-MI, and one CD-TLR (1.5%). POCE was observed in 6 (9.6%) patients. Stent failure was seen in 2 (3.1%) patient and one patient (1.5%) developed late stent thrombosis. Twelve months angiographic follow-up indicated intact stent patency in all other patients. On multivariate analysis, LM bifurcation, renal dysfunction, LM bifurcation with renal dysfunction, ejection fraction (<35%) and calcified lesion were found as predictors of TLF.

CONCLUSIONS

Dedicated stenting with ultra-thin Supra family SES for complex bifurcation lesion using nano-crush technique reported acceptable clinical outcomes among real-world patients and can be performed safely with ease without any procedural complications.

Coronary artery double stenting techniques and their results in complex left main bifurcation disease

Aim: Complex left main (LM) bifurcation disease seems to be better approached by a planned double stent technique. Materials & methods: Medline search for articles including randomized trials, prospective series, large registries and retrospective studies >50 patients has been performed. Results: Double kissing crush demonstrated its superiority over culotte stenting and cross over, while other techniques such as the T-stenting and T-stent and Protrusion have not been extensively reported in LM setting. The nano inverted-T-stenting has provided evidences that the use of ultrathin strut stents and very minimal crush is beneficial for both the physiological and rheological properties. Conclusion: The double stenting techniques used in LM should be evaluated in terms of procedural differences and technical simplicity.

Biomechanical Evaluation of Different Balloon Positions for Proximal Optimization Technique in Left Main Bifurcation Stenting

BACKGROUND

Proximal optimization technique (POT) is a key step during left main (LM) bifurcation stenting. However, after crossover stenting, the ideal position of POT balloon is unclear. We sought to evaluate the biomechanical impact of different POT balloon positions during LM cross-over stenting procedure.

METHODS

We reconstructed the patient-specific LM bifurcation anatomy, using coronary computed tomography angiography data of 5 consecutive patients (3 males, mean age 66.3 ± 21.6 years) with complex LM bifurcation disease, defined as Medina 1,1,1, evaluated between 1st January 2018 to 1st June 2018 at our center. Finite element analyses were carried out to virtually perform the stenting procedure. POT was virtually performed in a mid (marker just at the carina cut plane), proximal (distal marker 1 mm before the carina) and distal (distal marker 1 mm after the carina) position in each investigated case. Final left circumflex obstruction (SBO%), strut malapposition, elliptical ratio and stent malapposition were evaluated.

RESULTS

The use of both proximal and distal POT resulted in a smaller LM diameter compared to the mid POT. SBO was significantly higher in both proximal and distal configurations compared to mid POT: 38.3 ± 5.1 and 29.3 ± 3.1 versus 18.3 ± 3.6%, respectively. Similarly stent malapposition was higher in both proximal and distal configurations compared to mid POT: 1.3 ± 0.4 and 0.82 ± 1.8 versus 0.78 ± 1.2, respectively.

CONCLUSIONS

Mid POT offers the best results in terms of LCx opening maintaining slightly smaller but still acceptable LM and LAD diameters compared to alternative POT configuration.

Computational fluid dynamic-derived wall shear stress of non-significant left main bifurcation disease may predict acute vessel thrombosis at 3-year follow-up

Wall shear stress (WSS) plays a pivotal role on plaque progression in coronary artery disease. We assess the prognostic role of baseline mean WSS in developing a bifurcation-located myocardial infarction (B-MI) over the following 3 years in angiographically non-significant LM bifurcation disease. For this purpose, we retrospectively reviewed the procedural and medical records of consecutive patients evaluated in our center from 1st January 2014 to 1st January 2019 who had a non-significant LM bifurcation disease as evaluated at coronary computed tomography angiography (CCTA) and confirmed by coronary angiography. Each bifurcation model was reconstructed on the patient-specific geometries derived from the CCTA. The population was divided into two groups: patients with (n = 12) and without B-MI (n = 20) over the following 3 years. Both the mean WSSprox of each branch and the WSSentire_lesion of each vessel, adjusted for the respective mean lesions lengths and 3-dimensional percentage of stenosis (DS%), resulted in independent predictors of 3-year B-MI. Multivariate Cox-regression analysis confirmed that a baseline mean WSSentire_model ≥ 5.05 Pa (HR 1.98, 95% CI 1.83-2.10, p = 0.001) was a predictor of 3-year B-MI independently from the entire mean lesions lengths (HR 1.56. 95% CI 1.43.1.68, p = 0.002) and DS% (HR 1.26, 95% CI 1.18-1.37, p = 0.03). In conclusion, in patients with angiographically non-significant LM bifurcation disease, both the mean WSSprox of each branch and WSSentire_lesion of each stenotic vessel predicted the occurrence of B-MI over the following 3 years. Moreover, the WSSentire_bifurcation ≥ 5.05 Pa seems to be a predictor of 3-year B-MI independently from the DS% and lesions lengths.

Optimal Site for Proximal Optimization Technique in Complex Coronary Bifurcation Stenting: A Computational Fluid Dynamics Study

BACKGROUND/PURPOSE

The optimal position of the balloon distal radio-opaque marker during the post optimization technique (POT) remains debated. We analyzed three potential different balloon positions for the final POT in two different two-stenting techniques, to compare the hemodynamic effects in terms of wall shear stress (WSS) in patients with complex left main (LM) coronary bifurcation.

METHODS/MATERIALS

We reconstructed the patient-specific coronary bifurcation anatomy using the coronary computed tomography angiography (CCTA) data of 8 consecutive patients (6 males, mean age 68.2± 18.6 years) affected by complex LM bifurcation disease. Subsequently a virtual bench test was performed in each patient using two different double stenting techniques represented by the DK and Nano crush using the reconstruction of Orsiro stents (Biotronik IC, Bulack, Switzerland).

RESULTS

A significant reduction in the mean WSS values in all the lesion's sites was observed when the final POT was performed 1 mm distally the carina cut plane in both techniques. Moreover, a significant improvement in the mean WSS values of the entire SB (e.g. LCX) was obtained performing the POT 1 mm distally to the carina cut plane. The proximal POT resulted in larger area of lower WSS values at the carina using both the Nano crush and the DK crush techniques.

CONCLUSIONS

In patients with complex LM bifurcation disease the use of a final POT performed 1 mm distally to the carina cut plane might results in more favorable WSS patterns (i.e. higher WSS values) along all stented segments and, especially, along the entire LCX lesions.

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.

Impact of different final optimization techniques on long-term clinical outcomes of left main cross-over stenting

BACKGROUND

The optimal final optimization technique to be used in patients after Cross Over Left main stenting remainsdebatable.

AIM

We evaluate the impact of the post-optimization technique (POT), kissing balloon (KB) and the POT-side-POT techniques on both cardiovascular mortality and event-free survival in patients receiving left main (LM) cross-over stenting for an isolated/distal bifurcation LM disease.

METHODS

Clinical and instrumental records of 128 consecutive patients (102 males, mean age 73.39 ± 9.54 years old) with isolated distal/bifurcation LM disease and bypass surgery contraindications or refusal enrolled to receive LM cross-over stenting between the 1st January 2012 and the 1st January 2017 at two institutions: the Rovigo General Hospital (Rovigo, Italy) and the Alexandrovka Hospital University School of Medicine (Sofia, Bulgaria). Patients has been divided into three groups (POT, KB and POT-side-POT) according the optimal final optimization technique used while the 5-year cardiovascular mortality has been evaluated using the log-rank (Mantel-Cox) analysis.

RESULTS

Baseline angiographic characteristics of the LM disease were mostly equivalent among the three groups. Over a global follow-up of 61.03 ± 0.92 months, the rates of target vessel revascularization, acute myocardial infarction, and stent thrombosis, were not different among groups. Patients treated with POT had a slightly better long-term survival.

CONCLUSIONS

None of these optimization techniques appeared to have clearly better long-term outcomes after LM Cross-over stenting in our retrospective study. POT resulted in a slightly better survival compared to Pot-sid-POT and KB.