Provisional Reverse “Mini-Crush” Technique for Bifurcation Angioplasty

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J INVASIVE CARDIOL 2008;20:E154-E157

We describe 2 patients — one with a left anterior descending (LAD)/diagonal bifurcation and the other with a protected distal left main bifurcation — in whom the provisional reverse “mini-crush” technique was successfully used to accomplish revascularization.

Case 1. A 56-year-old female presented with an anterior ST-elevation myocardial infarction and ongoing chest pain with ST improvement post thrombolysis. A moderate-to-significant hazy lesion was noted in the mid-left anterior descending artery (LAD) (Figure 1A). Intravascular ultrasound (IVUS) of the LAD demonstrated a minimal luminal area of 2.8 mm2 with thrombus. After wiring the LAD and diagonal arteries, a 3.5 x 16 mm bare-metal stent was deployed in the LAD at high pressure with a good result (Figure 1B). There was, however, pinching of the diagonal ostium and a subsequent kissing inflation was performed with a 3.25 x 12 mm balloon in the LAD and a 2.0 x 12 mm compliant balloon in the diagonal (Figure 1C). This resulted in a localized dissection in the ostium of the diagonal (Figure 1D). Therefore, a 2.5 x 8 mm paclitaxel-eluting stent (PES) was passed into the diagonal with a 3.25 x 12 mm balloon “parked” in the LAD stent for balloon crushing (Figure 2A). The paclitaxel stent was brought back 1 mm into the LAD to ensure coverage of the true diagonal ostium and was deployed at 11 atm. The stent balloon was then pulled back 3–5 mm into the LAD and inflated to 18 atm to ensure high-pressure deployment of the ostium of the side-branch stent. Inflating the LAD balloon at high pressure then crushed the diagonal stent. After recrossing into the diagonal, kissing inflation was performed using a 3.5 x 12 mm noncompliant balloon in the LAD and a 2.5 x 8 mm balloon in the diagonal at 12 atm. A final high-pressure LAD inflation at 21 atm was done to avoid stent protrusion into the LAD from the diagonal stent (Figure 2B). An excellent angiographic result was achieved in both vessels (Figure 2C). The patient was rendered pain-free and is doing well at 3 months post intervention.

Case 2. A 68-year-old male with a history of remote coronary artery bypass graft surgery (CABG) presented with Canadian Cardiovascular Society Class III angina and occlusion of his saphenous vein grafts with a patent left internal mammary artery. A severe distal bifurcating left main artery was the likely culprit (Figure 3A). After the patient was turned down for repeat CABG, he was referred for percutaneous intervention of a complex bifurcation protected left main lesion. A 7 Fr large-lumen guiding catheter was chosen. Predilatation was performed in the circumflex and LAD arteries. A 3.5 x 20 mm PES was unable to be delivered into the angulated circumflex artery even after several wires were used; it was therefore deployed at high pressure from the left main into the LAD (Figure 3B). Kissing inflations were performed in the LAD and circumflex arteries (Figure 3C), however, the result was suboptimal in the ostial circumflex artery, which was the more important of the 2 vessels to be preserved in this case. Therefore, a 3.0 x 8 mm paclitaxel-eluting stent was delivered into the ostial circumflex artery with 1 mm protruding into the distal left main artery and was deployed at 12 atm. The same stent balloon was pulled back 3–4 mm and inflated at 18 atm to the ostium of the circumflex stent (Figure 4A). The previously-parked 3.5 x 12 mm balloon in the left main artery was used to crush the circumflex artery stent. Subsequently, multiple kissing inflations were performed in the distal left main bifurcation, and finally, a 4.5 x 12 mm noncompliant balloon was inflated at high pressures (18–22 atm) throughout the left main/LAD stent (Figures 4B and C), with optimal angiographic results (Figure 4D). Intravascular ultrasound (IVUS) performed post procedure demonstrated good apposition of the left main and circumflex stents with excellent ostial circumflex stent deployment, no significant protrusion and complete ostial coverage (Figures 5A and B) The patient remains anginafree at 3 months post intervention.

Discussion. Colombo et al initially described the crush technique as a method of bifurcation stenting that ensured ostial side-branch stent coverage.¹ Subsequently, the importance of appropriate final kissing balloon inflation with this technique was established.² In comparison with T-stenting, the crush technique with final kissing balloon inflation is associated with a reduced rate of restenosis in the side branch.³
There are several concerns surrounding the original crush technique. One such concern involves the 3–4 mm of drugeluting stent overlap at the bifurcation. Long-term (9-month) follow up of the crush technique has demonstrated stent thrombosis rates of up to 4.3%.⁴ Restenosis rates of the side branch have been reported to be as high as 25.3% in the same study.⁴ The use of mandatory high pressure in the side branch and kissing inflation during the crush technique has reduced side-branch restenosis rates to 8.6% in a more recent multicenter registry.³ Unfortunately, the rate of stent thrombosis in this registry was unchanged despite the fact that the kissing inflation rate remained at 3.3%.³ This remains at a troubling 3–4 times the expected rate for routine single-vessel stenting. The mini-crush technique (with step-balloon crushing), which calls for 1–2 mm of stent overlap, was demonstrated to have low major adverse cardiac event (MACE) and very low restenosis rates of 2.0% at the side-branch ostium in a small patient cohort.⁵ Procedural success rates for the crush technique have improved to > 95% in recent registries, however, the rates of final kissing inflation remain at 87.5%, leaving room for improvement.6 With the mini-crush technique, 100% procedural success has been reported, with final kissing inflation rates of 94%.⁵

The NORDIC I trial compared a provisional versus planned 2-stent technique (including crush) with drug-eluting stents.⁷ There was only a 2.7% crossover rate to the 2-stent technique in the provisional group, and no difference in MACE between the two groups at 6 months.⁷ In fact, reduced procedural and fluoroscopy times as well as lower contrast volume use were observed in the single-stent/provisional group.⁷ Another disadvantage for the crush and all dual-stent techniques is the increased cost due to the greater number of stents and related equipment required. The consensus method to deal with most routine bifurcations is clearly a single, main-branch stent with provisional side-branch intervention as needed. However, for those patients in whom sidebranch intervention is required due to dissection, compromised thrombolysis in myocardial infarction (TIMI) flow, ongoing chest pain or critical residual sidebranch disease in a significant vessel, other techniques such as the inverse-crush or provisional T-stenting technique are available. The reverse-crush technique (or “internal-crush”) is a provisional 2-stent technique that involves stenting the main branch, and in the presence of a suboptimal ostial side-branch result, passing a second stent into the side branch with 2–3 mm or more protruding into the main vessel and completion per the standard crush technique and kissing inflation.⁸ The only caveat regarding this technique is that final high-pressure inflation with an appropriate-sized balloon is required in the main vessel to prevent main-branch stent distortion.⁸

A high bifurcation angle (> 50 degrees) has been noted to be an independent predictor of MACE after crush stenting.⁹ This may be due to inadequate expansion of the side-branch stent ostium even after kissing inflation.9 Combining ostial sidebranch high-pressure balloon inflations and IVUS may be methods to ensure optimal stent expansion when tackling highly angulated bifurcations, as in the two cases discussed here.

We suggest a provisional reverse “mini-crush” technique (1 mm overlap), which is simply a combination of the reverse-crush and the mini-crush techniques. The benefit of this combined technique is that the opportunity to first perform single-stenting is preserved, while side-branch stenting can be performed only if required. This technique would also minimize the overlap of drug-eluting stents, similar to the mini-crush technique, thereby potentially reducing the risk of stent thrombosis. Recrossing into the side branch in both cases becomes reasonably simple, since with this technique, only one layer of stent needs to be crossed at any given time, similar to the Dzavik et al modified balloon-crush technique.¹⁰ This is because kissing inflation has generally been performed prior to insertion of the side-branch stent, thereby displacing the main vessel’s stent struts from the mouth of the side branch. The routine use of IVUS in complex bifurcations, as in our cases, to ensure optimal sidebranch and main-vessel stent deployment may be reasonable. In both our cases, IVUS was used to confirm complete side-branch ostium coverage. In the large multicenter TULIPE registry, 34% of side branches in the provisional stenting arm required crossover to side-branch stenting.¹¹ Given that bifurcations comprise 10–15% of percutaneous interventions, this technique may potentially be utilized in approximately 3–4% of all cases. The single-stent technique is still recommended as a first-line approach to bifurcation intervention, however, a larger registry or randomized comparison of the provisional reverse “mini-crush” technique to the single stent or other dual-stent techniques may be warranted to evaluate the former’s angiographic and long-term efficacy and safety.

References

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