Patients who underwent intentional stent fracture for maximally expanded pulmonary artery stents experienced few adverse events and may have experienced a hemodynamic benefit, according to results of a small retrospective cohort study.
Researchers evaluated 31 patients with maximally dilated branch pulmonary artery stents who underwent intentional stent fracture with ultra-high-pressure balloons vs. 62 controls with pulmonary artery stents who underwent redilation via ultra-high-pressure balloons without stent fracture, between 2004 and 2014. Among patients, fracture occurred in 33 stents (19 complete and 14 partial longitudinal fractures) a median of 10 years after placement; angioplasty was performed at 68 sites among controls.
The primary outcome was a composite of adverse events relevant to angioplasty and stent fracture, including vessel obstruction warranting reintervention caused by intimal flap, vessel wall rupture, stent or stent fragment embolization, balloon fragment embolization after balloon rupture and difficulty removing or inability to remove the balloon due to rupture or stent interference.
Patients in the fracture group had a larger nominal balloon diameter than controls (median, 14 mm vs. 12 mm; P = .001). Both groups exhibited reductions in pressure gradient after angioplasty, with similar gradients observed between patients and controls before (median, 20 mm Hg for patients vs. 15 mm Hg for controls; P = .38) and after treatment (median, 11 mm Hg vs. 3 mm Hg; P = .3).
Adverse events occurred at similar rates between the groups (five events in the fracture group vs. six among controls; P = .34). Among patients, events included one incidence of stent embolization, two vessel ruptures and two intimal tears; events in the control group included two vessel ruptures, one balloon rupture, one aneurysm formation and two intimal tears. No patients with stent fracture experienced major pulmonary artery complications, the researchers wrote.
Follow-up catheterization was performed in 10 patients a median of 2 years after intentional fracture. The mean pressure gradient was 14 mm Hg, which did not differ significantly from that observed after dilation (P = .63). No patients exhibited vessel obstruction or stent fragment embolization related to the intentional fracture, and no patients required placement of additional stents. The researchers noted that one control patient developed an aneurysm distal to the stent 4 years after dilation, which was considered related to the index procedure.
“In this preliminary study, there were few adverse events associated with intentional fracture of previously implanted, maximally expanded [pulmonary artery] stents,” the researchers concluded, noting that the small size of the study limited its power and the ability to generalize its results. “Although the likelihood that [pulmonary artery] stents can be fractured using [ultra-high-pressure] balloons could not be determined, when an intentional fracture was achieved, it seemed to result in hemodynamic benefit and was not associated with a significant increase in the rate of complications when compared with [ultra-high-pressure] angioplasty without a stent fracture.” – by Adam Taliercio
Disclosure: The researchers report no relevant financial disclosures.