Final Kissing Balloon Counters Ill Effects of Side Branch Dilation in Bifurcation Stenting

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In patients undergoing percutaneous treatment for bifurcation lesions, both stent volume and symmetry are reduced in the main vessel by side branch dilatation. But finalizing the procedure with kissing balloon inflation can counter these ill effects, reports an intravascular ultrasound (IVUS) study published online August 14, 2013, ahead of print in JACC: Cardiovascular Interventions.

Massoud A. Leesar, MD, of the University of Alabama (Birmingham, AL), and colleagues performed 88 serial IVUS examinations in 22 patients with coronary bifurcations who were treated via a simple single-stent strategy. Most patients received first-generation stents eluting either sirolimus (50%) or paclitaxel (36.4%).

Side branch dilatation, performed after main vessel stenting, decreased the stent volume index (SVI), minimal stent area (MSA), and stent symmetry index (SSI) in the bifurcation segment. However, kissing balloon inflation restored all 3 measures. No differences were observed in external elastic membrane (EEM) volume (table 1).

Table 1. Bifurcation Segment: Quantitative IVUS Results

Abbreviations: EEM, external elastic membrane; MSA, minimal stent area; SSI, stent symmetry index; SVI, stent volume index.

^aP < 0.05 vs. after main vessel stenting.

In the proximal segment, main vessel SVI and MSA were both larger after kissing balloon inflation and EEM volume index increased, though SSI was smaller (P < 0.01 for all). Neither main stent volume nor symmetry was affected by side branch dilation or kissing balloon inflation in the distal segment.

Each patient received only 1 stent, because there were no cases of side branch dissection after dilation. Moreover, there were no cases of stent-related complications such as dissection, perforation, or stent thrombosis, and all patients were discharged after an overnight stay.

However, the full clinical impact of kissing balloon inflation has yet to be seen, the investigators conclude, noting, “Although [kissing balloon inflation] is commonly being performed, its long-term impact on patient outcomes cannot be ascertained based on current studies and requires further investigation.”

Confirmation of Earlier Studies

Dr. Leesar told TCTMD in a telephone interview that it has been known for over a decade that kissing balloon inflation rectifies the changes in stent geometry seen after side branch dilatation (Ormiston JA, et al. Catheter Cardiovasc Interv. 1999;47:258-264). What the current study adds, he said, is IVUS confirmation of the technique’s effects on lumen and volume.

“We thought for years it was only a matter of geometry changes, [which] have nothing to do with restenosis and don’t have much clinical impact,” Dr. Leesar observed. “What is important for drug-eluting stents is the lumen area. If the lumen area is smaller, that will impact stent thrombosis, MI, and all those subsequent events.”

Second-generation DES have thinner struts and thus possibly enable better side branch flow, which might eliminate the need for kissing balloon inflation, Dr. Leesar suggested, noting that this theory has yet to be tested.

Not a Mandatory Step When Stenting

Jeffrey W. Moses, MD, of Columbia University Medical Center/Weill Cornell Medical Center (New York, NY), told TCTMD in a telephone interview that the paper provides “elegant confirmation” in vivo of prior models showing how kissing balloon inflation can help alleviate the damage done during side branch dilatation.

However, final kissing balloon inflation is not always necessary, he stressed, noting it is only one of many techniques used in bifurcation stenting. “It’s clear that there’s no necessary benefit to doing it a priori,” he said. “You don’t just kiss because there’s a branch there. . . . If the branch looks OK, we generally leave it alone these days.”

In an e-mail communication with TCTMD, David Hildick-Smith, MD, of Royal Sussex County Hospital (Brighton, United Kingdom), agreed. “This is very much a matter for individual discretion,” he said. “The evidence would suggest that there is no specific penalty for doing kissing balloon inflation. Neither is there an obvious gain to be had. It remains controversial because we do not know what to do, and yet we encounter bifurcation lesions all the time.

“A very reasonable approach,” he continued, “is to do kissing balloon inflations on any large side branch that is more than 75% narrowed—only 30% of them will be physiologically significant, but if the procedure is done carefully there will be no significant downside among the 70% who have physiologically nonsignificant side branch narrowing.”

The results of the current study are “descriptive,” rather than promoting wider use of kissing balloon, Dr. Hildick-Smith said, “and simply document the effect of kissing balloon inflation.”

Why Not Kiss?

According to Dr. Leesar, the main downside to final kissing balloon inflation is the possibility of dissection, which did not occur in the current study.

Dr. Hildick-Smith proposed that the main argument against the technique “is that the introduction of any degree of added complexity to a procedure, no matter how small, introduces the possibility of screwing up a perfectly decent result. This is true of kissing balloon inflation procedures, and there are pitfalls which need to be avoided if the procedure is to be undertaken successfully. As ever, the most important point relates to operator experience and proficiency.”

 

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Source:
Rahman S, Leesar T, Cilingiroglu M, et al. Impact of kissing balloon inflation on the main vessel stent volume, area, and symmetry after side-branch dilation in patients with coronary bifurcation lesions: A serial volumetric intravascular ultrasound study. J Am Coll Cardiol Intv. 2013;Epub ahead of print.

 

 

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