Balloon-Free PCI for SVG Stenosis Offers Ongoing Advantages: DIVA

Direct stenting during saphenous vein graft (SVG) percutaneous coronary intervention improves safety not just in the short term but also thereafter, a post hoc analysis from the DIVA trial suggests.

Compared with procedures that involved balloon pre- or postdilation, the stent-only strategy offered the same risk of target-vessel failure (TVF) at 12 months, as well as reductions in stent thrombosis and target-vessel MI at a median of 2.7 years.

Already, “the expert opinion is to try to avoid balloon angioplasty in vein grafts whenever possible,” lead author Faisal Latif, MD (Oklahoma City VA Medical Center, OK), told TCTMD.

This is because earlier studies have shown that primary stenting carries less risk of periprocedural MI and need for TLR, “possibly due to lower risk for distal embolization,” the researchers note in their paper published online recently in Circulation: Cardiovascular Interventions. “Similarly, postdilation of SVG lesions could lead to plaque protrusion through the stent struts (cheese-grater effect) leading to distal embolization and periprocedural myocardial infarction, which has been associated with higher mortality.”

What’s new here is the notion that these periprocedural benefits extend over the long term, Latif said, “which is pretty surprising” and should make operators circumspect about the risks of balloon angioplasty in SVG PCI.

DIVA Dissected

Latif and colleagues assessed outcomes among 575 patients who underwent PCI to treat a de novo SVG stenosis of 50% to 99% between 2012 and 2015. Around one-third (32%) had stent-only procedures, while 68% had balloon-stent SVG PCI. Demographic, angiographic, and procedural characteristics were similar at baseline in the two groups, although the target SVG lesion was more often located in the SVG body among the stent-only patients.

By 12 months, the primary endpoint of TVF (cardiac death, target-vessel MI, or TVR) did not differ between stent-only and balloon-stent PCI (15% vs 19%; P = 0.19).

Over the 2.7-year follow-up, TVF remained similar in the two groups (38% vs 33%, respectively, P = 0.43). Patients in the balloon-stent group, however, were more likely than those in the stent-only group to develop definite stent thrombosis, definite/probable stent thrombosis, and target-vessel MI.

SVG PCI: Outcomes at a Median of 2.7 Years

On multivariable analysis, a longer time since CABG and the presence of more than one SVG lesion each were independently linked to higher long-term risk of TVF. Patients with TIMI flow 3 prior to PCI were less likely to experience TVF. Use of a balloon before or after stenting had no effect on that endpoint over 2.7-year follow-up.

There are several potential explanations for why the risk of stent thrombosis was elevated in the balloon-stent group, the researchers comment.

“First, lesions treated with adjunctive balloon angioplasty were more likely to be located at the aortic or distal anastomosis, which may be more difficult to expand, as aorto-ostial lesions are more likely to be calcified, and both aorto-ostial and distal anastomotic lesions are affected by postsurgical fibrotic changes,” they explain. “In contrast, SVG body lesions more commonly include softer, friable plaque and might require less lesion preparation with predilation.”

Additionally, distal embolization due to balloon angioplasty, when it occurs, can lead to myocardial angioplasty and reduced flow, Latif et al continue, adding that balloon use also “may cause more extensive SVG wall injury, potentially triggering formation of neointima and neoatherosclerosis that could form the nidus for subsequent stent thrombosis and/or restenosis.”

They acknowledge, too, that there could be unidentified lesion characteristics at work.

These results support balloon-free stenting in SVG lesions, but this may not always be possible, Latif noted to TCTMD. “Some lesions, when you look at them as an operator you know that you will need a balloon—they’re so tight that you cannot get your distal protection device through.” Or, as the researchers point out, postdilation may be required to optimize stenting.

“It has been classic clinical teaching to avoid balloon angioplasty, but it is not followed strictly” in actual practice based on the perception that the risks are restricted to the first few days post-PCI, Latif said. This appears to not be the case.

“I think [our study] has important implications and should change practice. Operators and that includes myself—I’ve been an interventional cardiologist for over 10 years—casually we balloon everything” and aren’t always attentive to the unique needs of vein grafts, he observed. “After this paper, I think people need to be more careful about ballooning. . . . Even if the patients don’t have periprocedural MI as a result of using balloons in SVGs, there is concrete concern [about the potential] for late stent thrombosis and target-vessel MI.”