Comparison of Jailed Wire and Jailed Balloon for Prevention of Side Branch Occlusion in Provisional Stenting: Evidence from a Systematic Review and Meta-Analysis

Background: Side branch (SB) occlusion after main vessel stenting is the main complication in treating coronary bifurcation lesions by provisional stenting. The Jailed Wire Technique (JWT), recommended by the European Bifurcation Club, is a standard technique to deal with this issue. The Jailed Balloon Technique (JBT) has been found to be more effective than the JWT in clinical practice by some interventionists, but it has not been widely accepted. In this meta-analysis, we compared the efficacy and safety of JBT and JWT. Methods: The literature comparing JBT and JWT was systematically reviewed. Stata/MP 17.0 was used to perform a meta-analysis. The primary endpoints were major adverse cardiac events (MACE), cardiac death, myocardial infarction (MI) and target lesion revascularization (TLR). The secondary endpoints were SB occlusion and SB dissection. Aggregated odds ratios and 95% confidence intervals were calculated. A sensitivity analysis was conducted if I2 was >50% or p < 0.01. Results: Thirteen studies involving 1789 patients were enrolled. JBT was found to have a significantly lower incidence of MACE, SB occlusion and dissection. The incidence of cardiac death, MI and TLR were also lower in the JBT group, though the differences were not significant. Conclusions: JBT prevents SB occlusion more effectively and does not increase immediate or long-term complications. JBT, or its modified versions, can be used to treat SBs with a high risk of occlusion.


Introduction
Side branch (SB) occlusion after main vessel stenting is the main complication during treatment of coronary bifurcation lesions by provisional stenting.The Jailed Wire Technique (JWT) has been recommended by the European Bifurcation Club (EBC) as a standard technique to deal with this issue [1].However, data from several studies revealed that the efficacy of JWT was limited.In most cases, the jailed wire only acted as a marker or path to rescue the compromised SB [2].Burzotta et al. [3] first proposed the Jailed Balloon Technique (JBT) in 2010, in which a small balloon was jailed in place of a guidewire.With the JBT, the incidence of SB occlusion could be significantly reduced due to the larger spatial occupation.However, to the best of our knowledge, JBT increased the risk of vessel dissection especially in the SB ostium.There is currently no clear evidence as to whether JBT or JWT should be adopted when performing provisional stenting.This systematic review and meta-analysis sought to clarify this issue by comparing the immediate procedural outcomes and long-term follow-up of these two techniques.This metaanalysis was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analysis and the Cochrane Collaboration guidelines, and has been registered on https://inplasy.com/(INPLASY202310082).

Literature Searching Strategy
A systematic literature search was performed with PubMed, Ovid Medline, Web of Science, Embase, Cochrane, CNKI, Wanfang and Weipu from the databases inception to January 2023.The search items and strategy were "jailed balloon" or "jailed wire" and "bifurcation".All relevant references were evaluated for addition once they met the inclusion criteria.

Literature Inclusion and Exclusion Criteria
Inclusion criteria included: (1) randomized controlled trials (RCTs) or observational studies comparing the JBT and JWT; (2) studies using drug-eluting stents.
Exclusion criteria included: (1) studies with unclear descriptions of the techniques or endpoints; (2) studies without the specified endpoints; (3) studies of low quality assessed by two independent reviewers; (4) repeated stud-ies; (5) studies whose full text couldn't be retrieved; (6) conference papers.

Endpoints
Primary endpoints: major adverse cardiac events (MACE) and its individual components including cardiac death, myocardial infarction (MI), target lesion revascularization (TLR).

Data Extraction and Quality Assessment
DL and HL extracted the data from the enrolled literature and independently assessed the qualities.Any conflict was resolved through discussions with HD.The extracted data included baseline characteristics of the enrolled studies and participants, and specified outcomes.The quality of RCTs was assessed with the Cochrane Collaboration tool [4].The quality of observational studies was assessed with the Newcastle-Ottawa Quality Assessment Scale [5].Any literature assessed as low quality by two reviewers was excluded.

Statistical Analysis
Aggregated odds ratios (OR) at 95% confidence intervals were calculated with Stata/MP 17.0 (Lakeway Drive, College Station, TX, USA).Heterogeneity between the studies was explored using the I 2 test.The random-effects model was used when p < 0.01 or I 2 > 50%, if not, the fixed-effects model was used.A heterogeneity test and sensitivity analysis were performed to select the origin of heterogeneity.Funnel plots and a regression-based Egger test were used to assess publication bias.The difference was considered statistically significant for a p-value < 0.05.

Searching Results and Baseline Information
Eight databases were searched.From the 218 identified studies, 129 were excluded for being duplicates, 69 were excluded for not meeting the inclusion criteria, two were excluded for not retrieving the full text, and seven were excluded for meeting the exclusion criteria.Two were added by reviewing the relevant references.Finally, 13 studies involving 1789 patients were enrolled, including four published in English and nine published in Chinese [6][7][8][9][10][11][12][13][14][15][16][17][18].The flowchart for identifying these studies is shown in Fig. 1.

Side Branch Occlusion
SB occlusion was reported in ten studies [6-8,10-12, 14,16-18].I 2 was 0.00, indicating that the heterogeneity of these studies was small.Funnel plots and regressionbased Egger test showed no evidence of publication bias (p = 0.36) (Fig. 3E).Meta analysis with a fixed model revealed that JBT had a significantly lower SB occlusion compared with JWT (p = 0.00).The aggregated OR value was 2.61 (Fig. 8).

SB Dissection
SB dissection was reported in three studies [6,9,14].I 2 was 0.00, indicating that the heterogeneity of these studies was small.Funnel plots and regression-based Egger test showed no evidence of publication bias (p = 0.27) (Fig. 3F).Meta analysis with a fixed model revealed JBT had a significantly lower SB dissection rate compared with JWT (p = 0.00).The aggregated OR value was 5.59 (Fig. 9).

Discussion
Coronary bifurcation lesions constitute 15-20% of percutaneous coronary interventions.SB occlusion caused by carina or plaque shift could lead to perioperative MI or death.JWT has been recommended by the EBC as a routine maneuver to prevent SB occlusion or facilitate rescuing a compromised SB.However, clinical practice revealed that the preventative effect of JWT was limited.JBT appears to decrease SB occlusion, but it has not been widely accepted in clinical practice due to a lack of clinical studies.
As far as we know, this is the first systematic review and meta-analysis to compare the JWT and JBT.In this present review, 13 studies were reviewed and six endpoints were analyzed.The heterogeneity between these studies was small.No evidence of publication bias was observed.According to the results, the individual rates of cardiac death, MI, and TLR were not significantly different between the techniques.However, the composite of MACE, as well as the secondary endpoints of SB occlusion and dissection were significantly lower in the JBT group.However, JWT is favored for its lower rates of dissection in clinical practice.In the literature, JBT has been shown to increase the risk of dissection, especially when the jailed balloon is inflated [19,20].Since these reports were singlearm studies, they were not enrolled in this review.We can conclude from this meta-analysis that JBT is a more effective and safer technique by reducing both procedural SB occlusion and long-term MACE.
NOS, Newcastle-Ottawa Quality Assessment Scale.The reasons that JBT performed better than JWT include: (1) larger spatial occupation to prevent carina or plaque shift; (2) prompt dilation to restore SB flow once it was compromised; and (3) angle modifier facilitating SB rewiring.
Another issue we should be concerned with is balloon entrapment.Through searching the relative literature, we     only find one case of balloon entrapment in a calcified lesion [21], but lots of wire entrapment when adopting JWT.Balloon entrapment never happened in our own experience.This might attribute to hydrophilic coating of a balloon.Furthermore, we could retrieve the jailed balloon after successive maneuvers of inflating and deflating it.
After Burzotta et al. [3] proposed JBT in 2010, it was further modified by different versions, such as modified JBT, jailed semi-inflation technique, balloon stent kissing technique and so on [22][23][24].They differed mainly in the balloon positions, inflation pressure and timing.It was still not clear which version performed best.However, results of this meta-analyis would suggest that JBT was better than JWT.Further clinical evidences and net-work metaanalysis are needed to compare the different JBTs.

Limitations
The main limitations of this study are: (1) the sample size was relatively small; (2) the definitions of endpoints varied across different studies; and (3) the techniques of JBT differed amongst the studies.

Conclusions
JBT can prevent SB occlusion more effectively and did not cause any increase in immediate or long-term complications.JBT or its modified versions might be the technique of choice in treating those SBs with a high risk of occlusion.

Fig. 4 .
Fig. 4. Forest plot for comparisons of MACE between JBT and JWT.MACE, major adverse cardiac event; JBT, jailed balloon technique; JWT, jailed wire technique.Studies in blue font are randomized controlled trails, while those in orange font are observational studies.

Fig. 5 .
Fig. 5. Forest plot for comparisons of cardiac death between JBT and JWT.JBT, jailed balloon technique; JWT, jailed wire technique.Studies in blue font are randomized controlled trails, while those in orange font are observational study.

Fig. 6 .
Fig. 6.Forest plot for comparisons of MI between JBT and JWT.MI, Myocardial infarction; JBT, jailed balloon technique; JWT, jailed wire technique.Studies in blue font are randomized controlled trails, while those in orange font are observational studies.

Fig. 7 .
Fig. 7. Forest plot for comparisons of TLR between JBT and JWT.TLR, target lesion revascularization; JBT, jailed balloon technique; JWT, jailed wire technique.Studies in blue font are randomized controlled trails, while that in orange font is an observational study.

Fig. 8 .
Fig. 8. Forest plot for comparisons of side branch occlusion between JBT and JWT.JBT, jailed balloon technique; JWT, jailed wire technique.Studies with label of blue font were randomized controlled trails, while orange font were observational studies.

Fig. 9 .
Fig. 9. Forest plot for comparisons of side branch dissection between JBT and JWT.JBT, jailed balloon technique; JWT, jailed wire technique.Studies with label of blue font were randomized controlled trails.

Table 1A . Baseline characteristics of the enrolled studies and subjects.
JWT, jailed wire technique; JBT, jailed balloon technique; RCT, randomized controlled trails; PCI, percutaneous coronary intervention.