Acute coronary syndromes (ACS) refer to a spectrum of acute myocardial ischemia and/or necrosis usually secondary to reduction in coronary blood flow and include unstable angina, non-ST-elevation myocardial infarction, and ST-elevation myocardial infarction [1, 2]. The incidence of ACS is approximately 1 million cases in the United Stated and 2 million in Europe [2]. Due to the rapid economic development of the Asia-Pacific region, including China, < 50% of the adults meet the NCEP-ATPIII low-density lipoprotein cholesterol levels [3, 4], resulting in significant mortality and morbidity [5, 6].

Atherosclerosis development involves the interplay of cardiovascular risk factors, inflammation, vascular biology and local hemodynamics [7]. Vascular geometries characterized by changes in lumen size predispose to plaque development [7]. Artery bifurcations are prone to develop atherosclerosis lesions because of the high shear stress and endothelial erosion from the turbulent blood flow [8, 9].

Approximately 15 to 20% of percutaneous coronary interventions (PCI) are performed to treat coronary bifurcation lesions [10, 11]. PCI of bifurcation lesions is technically challenging and associated with lower success rates and higher frequency of immediate and long-term adverse outcomes [12, 13]. Despite randomized studies and observational series, the selection of the optimal interventional strategy for true coronary bifurcation lesions remains controversial because of the variability in side branch (SB) disease and the desire to preserve the patency of the SB [14, 15].

According to previous studies, the one-stent strategy with provisional SB stenting is superior to the elective two-stent strategy and considered as the first option for most coronary bifurcation lesions [16, 17]. A modification of the provisional stenting strategy called the jailed-balloon technique (JBT) is designed to reduce SB occlusion during main vessel (MV) stenting, but cannot fully prevent it [18, 19].

Therefore, the aim of the present study was to explore the immediate and long-term treatment effect and adverse events of a new modified JBT for SB protection during PCI on coronary bifurcation lesions. This new technique could improve the prognosis of patients with bifurcation lesions treated with PCI.

PCI of bifurcation lesions is technically challenging and associated with lower success rates and higher frequency of adverse outcomes. The objective of the present study was to evaluate the immediate and long-term treatment effect and adverse events of a new modified jailed-balloon technique on side branch (SB) during PCI on coronary bifurcation lesions. The results suggest that the modified JBT provided high rate of procedural success, excellent SB protection during MV stenting, and excellent immediate and long-term clinical outcomes.

In our study, the majority of patients presented with ACS (91.7%) and 71.7% bifurcation lesion were Medina type 1.1.1. All 60 (100%) patients successfully underwent this modified JBT. Although there were high clinical and angiographic risks for SB occlusion during MV stenting, we did not observe any SB occlusion post-procedure. Indeed, the advantage of this technique is that acute occlusion of SB is very unlikely to happen because the SB balloon is expanded while the stent is inflated, so that the blood vessels on the SB will not show a snow shoveling effect, and the ostium will not be occluded. Hence, the peri-procedural MI rate was 0% and there was no MACE during in-hospital stay and 9-month follow-up, and most (91.7%) patients achieved CCS I stage. Depta et al. [26] showed that JBT was associated with a significantly lower rate of MACE compared with no JBT. Therefore, we think that this modified JBT could be better than JBT.

Previously, the jailed guidewire technique has been proven to be effective during the provisional technique [27], and it is nowadays widely adopted in the clinical practice but is also associated with the risk of jailed wire entrapment and does not abolish the risk of SB occlusion. Furthermore, there are several reports of severe complications caused by guidewire fracturing during withdrawal [28]. Burzotta et al. [19] developed the “jailed-balloon technique,” a modified provisional method. In this new method, SB was lost after MV stenting in 15% of patients. Furthermore, they had to implant another stent to SB due to suboptimal outcomes in 50% of patients. Therefore, the risk of SB occlusion is present after MV stenting due to plaque shift into the SB [29]. Compaired with original JBT of Burzotta et al.,which SB balloon are only semi-inflated, the main difference of our modified JBT is that SB balloon was inflated to fully normal pressure. By this new modified JBT, the SB ostium stenosis could be adequately reshaped and no patient suffered from TIMI flow 0 in SB.

The major issues about the modified JBT are the possible risk of MV stent struts distortion/malapposition in the MV proximal segment, entrapment of the SB balloon under the MV stent, and SB ostial dissection. As described in the Methods, the proximal markers of the SB balloon were not beyond that of the MV stent, and the distal markers covered the SB ostium lesion. Because of this, the jailed SB balloon was removed successfully in all patients without damage or entrapment of the balloon, as observed in previous studies [19, 30]. Because the SB balloon is inflated to its nominal pressure, SB ostium stenosis could be adequately reshaped, as in a study by Cayli et al. [31], and no patient suffered from TIMI flow 0 in SB. Good outcomes were also observed in a Japanese study using a modified JBT that is slightly different from ours in the choice of stents [32]. And the good long-term effect was observed in the imaging of many patients in our study and SB Balloon markers(Black arrow) was pointed (Fig. 2).

Although SB TIMI 1 was observed in one patient (1.7%) and TIMI 2 in three (5%) patients. In the four cases’ with SB blood low flow, the diameter of SB was 2.5–3.0 mm. According to our research experience, SB slow flow happened due to lesion type all Medina 1.1.1,and the serious stenosis(more than 90%),not by diameter and length of the SB. However, Those patients did not need another stent to SB and recovered to TIMI 3 in SB at 9 months. That is advantage of this modified JBT technology. By this new modified JBT, the SB ostium stenosis could be adequately reshaped, and it might cause no flow fo more dissection happen by two times dilation of SB. On the other hand, proximal MV stent shape was well inflated. After both inflations, if SB >2.5 mm, for optimization of MV stent apposition, the POT was routinely performed with a short non-compliant balloon after removing the jailed balloon. Due to POT, MV stents were well expanded in all patients of the present study. Compared with baseline, the MLD was significantly different after the procedure and after 9 months. All PCI in the present study were performed using 6Fr-guiding catheters via a transradial approach, resulting in less pain after the procedure.

The present study has some limitations. First, the sample size was relatively small. Secondly, the study population was relatively homogenous, characterized by Chinese adults, middle- and old-aged, presenting at a single health Institute. Thirdly, this technique was not compared with other techniques such as traditional provisional technique and JBT. Fourthly, the follow-up was short. Finally, intravascular ultrasound (IVUS) or optical coherence tomography (OCT) were not used in our study. Nevertheless, the present study provides preliminary data for future multicenter randomized controlled trials.

This modified JBT showed a high rate of procedural success and excellent SB protection during PCI of coronary bifurcation lesions. The treatment effect was good and there were no adverse events immediately after the procedure and during the 9-month follow-up.