Treatment of calcified lesions with bioresorbable scaffolds (BRS) is feasible and yields angiographic success that matches what can be achieved for noncalcified lesions, according to a small study published online March 31, 2015, ahead of print in EuroIntervention. However, there was a trend toward more periprocedural MIs in patients with calcified lesions. 

“Operators should pay particular attention to meticulous lesion preparation with dedicated devices when needed, in order to achieve optimal stent apposition and expansion,” advise Antonio Colombo, MD, of San Raffaele Hospital (Milan, Italy), and colleagues.

The investigators assessed 163 patients treated with the everolimus-eluting Absorb BVS v1.1 (Abbott Vascular) at 2 Italian centers between May 2012 and May 2014. Procedural and clinical outcomes were compared between the 38% who had at least 1 calcified lesion (defined as calcium arc > 90° on IVUS or at least moderate calcification on angiography) and those whose lesions lacked calcification.

Mean age (nearly 64 years), proportion of men (about 90%), and clinical presentation (about 84% stable angina) were similar between the groups. Patients with calcified lesions had a higher prevalence of chronic kidney disease and a trend toward more diabetes than those without such lesions. They also had a higher mean SYNTAX score (18.9 vs 15.1; P = .017).

In addition, QCA parameters were similar between the lesion types. Predilatation, scoring balloons, and rotational atherectomy were all more frequently used in calcified lesions. Calcified vessels were also more likely to undergo IVUS imaging (P < .001), which facilitated the use of more appropriately sized balloons for postdilatation. Procedural and fluoroscopy times were longer in patients with calcified lesions than in those without (P = .015 and .021, respectively), as was total BRS stent length (52.1 vs 43.8 mm; P = .046). 

Procedural Outcomes Acceptable

After implantation, there were no differences between calcified and noncalcified lesions in acute gain, minimal lumen area gain, or angiographic success (defined as a minimum stenosis diameter < 20% by QCA with TIMI flow grade 3 without occlusion of a clinically significant side branch, flow-limiting dissection, distal embolization, or angiographic evidence of thrombus). However, calcified lesions showed less procedural success and a trend toward more periprocedural MI (table 1).

  

At 1 year, there were no differences between the groups in Kaplan-Meier estimated rates of MACE (all-cause mortality, nonprocedural MI, and any revascularization) or TLR (table 2).

   

In addition, at a median follow-up of 14 months, the noncalcified group had experienced 1 death, 3 postprocedural MIs, and 1 case of acute definite stent thrombosis, while the calcified group had no deaths, 1 postprocedural MI, and 1 case of late definite stent thrombosis. None of the differences was statistically significant.

BRS Carry Advantages

The eventual resorption of BRS allows for future grafting of stented segments and facilitates reopening of “jailed” side branches and the disappearance of overhang at ostial lesions, the authors say. These benefits are especially important in patients with calcified lesions, who often have extensive CAD that requires stenting of long segments.

It remains to be seen whether scaffold resorption enables partial restoration of physiological vessel motion and expansive remodeling in noncircumferential calcified lesions or in circumferential calcified lesions treated with atherectomy or with cutting or scoring balloons, they add.

“Treating lesions in noncompliant vessels increases the odds of stent underexpansion, and difficulties in device delivery may strip the polymeric material with ensuing compromise in local drug elution,” Dr. Colombo and colleagues observe. Because underexpansion can be subtle, use of IVUS and QCA is key in treating these lesions, they advise.

BRS More Technically Challenging to Deliver Than DES

“[T]he advent of [BRS] may justify a decalcification strategy followed by [BRS] implantation for diffusely diseased, calcific arteries,” the investigators remark. “However, unlike the second- and third-generation DES, the delivery of first-generation [BRS] in calcified lesions can be more challenging due to [the devices’] strut thickness…. Furthermore, when stretched beyond its designed limits and after partial bioabsorption as time goes by, a [BRS] may lose some of its radial strength and may be prone to acute or late recoil.” 

In an email with TCTMD, Stephen G. Ellis, MD, of the Cleveland Clinic (Cleveland, OH), confirmed that calcified lesions are more technically challenging. “Unless care is taken, I suspect that in addition to more periprocedural MIs—there’s debate about what enzyme level really translates into long-term risk—there will be increased risk of acute scaffold thrombosis,” he wrote. “[However, there are] too few patients to know if at least moderate calcium will portend worse long-term outcomes.

Note: Dr. Colombo is a faculty member of the Cardiovascular Research Foundation, which owns and operates TCTMD.

 

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Source: 
Panoulas VF, Miyazaki T, Sato K, et al. Procedural outcomes of patients with calcified lesions treated with bioresorbable vascular scaffolds. EuroIntervention. 2015;Epub ahead of print.

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