Impact of Calcium Cracks after Balloon Angioplasty in Patients with Complex Calcified Coronary Plaque The Results of the OCT-CALC Registry

BackgroundTarget lesion calcification is known to influence the percutaneous coronary intervention (PCI) outcomes. Calcium cracks as assessed by optical coherence tomography (OCT) after balloon angioplasty were associated with a larger stent area and a larger lumen gain after PCI for the lesions with moderate to severe calcification, although clinical outcomes in those patients remain unclear. This study aimed to assess the impact of calcium cracks after balloon angioplasty on the PCI results as well as the long-term clinical outcomes by multicenter OCT-guided PCI registry. MethodsWe formed a prospective, multicenter registry that include 22 sites from Japan and Korea that enrolled 268 patients who underwent PCI to the lesion with moderate to severe calcification on angiogram. Balloon dilatation and subsequent drug elution stent (DES) implantation were performed with OCT guidance in every case. Lesion modification with rotational atherectomy was performed before balloon dilatation if needed. Serial OCT images just before and after balloon angioplasty, and after stent implantation were analyzed at 1-mm intervals by an independent core laboratory. The incidence of calcium cracks after balloon angioplasty was assessed at the minimal lumen area (MLA) site by OCT. By protocol, follow-up angiography was performed 10 months after PCI (in 85.5% of patients), and both baseline and follow-up angiograms were analyzed by an angiographic core laboratory. The primary endpoint was the relationship between calcium crack after balloon angioplasty and stent expansion. The secondary endpoint was target vessel failure (TVF) at 1 year, defined as a composite of cardiac death, target vessel-related myocardial infarction, and target vessel revascularization. ResultsA total of 242 patients were analyzed. Of these, OCT analysis was performed in 147 patients with a complete OCT data set. Calcium cracks were observed in 28 patients (19%) at the MLA site. The percent stent expansion was greater in lesions with calcium crack than those without (99{+/-}26 % vs. 91{+/-}18 %, p=0.039). In 229 patients who underwent clinical follow-up at 1 year, TVF occurred in 23 patients (10.0%). In 139 patients in whom both OCT analysis and 1-year clinical follow-up was performed, the incidence of TVF was similar between patients with and without crack formation (11 % vs. 13 %, p=1.00). Angiographic sub-analysis with both baseline and 10-months follow-up was performed in 124 patients. Acute lumen gain, as well as late lumens loss, were greater in patients with calcium crack than those without (1.39{+/-}0.55 mm vs. 1.15{+/-}0.48 mm, p=0.037; 0.51{+/-}0.67 mm vs. 0.12{+/-}0.51 mm, p=0.0095, respectively), resulting in similar net lumen gains between the 2 groups. ConclusionThe OCT-guided PCI strategy demonstrated acceptable acute and 1-year clinical outcomes. The presence of calcium cracks after balloon angioplasty may have a potential impact on acute results after DES implantation in calcified lesions. However, its impact may be attenuated by late lumen loss at 10-months follow-up.