Nicolas Meneveau (Besancon, France) told delegates at the 2016 European Society of Cardiology (ESC) congress (27–31 August, Rome, Italy) that percutaneous coronary intervention (PCI) guided by optical coherence tomography (OCT) results in significantly higher post procedure fractional flow reserve (FFR) values than PCI guided by angiography alone. He added that this benefit was mainly driven by optimisation of stent expansion.
According to Meneveau (University Hospital of Besancon, Hospital Jean Besancon, Besancon, France), OCT offers “potential advantages over angiography” and a previous study has already indicated that OCT-guided PCI affects decision-making “in two thirds of cases”. However, he noted: “It remains to be investigated whether the use of additional interventions prompted by OCT findings will translate into a benefit in procedural outcome. In this setting, randomised data investigating the utility of OCT over angiography alone to guide PCI are lacking; specifically in patients with non-ST-segment elevation (NSTE) acute coronary syndromes.”
Therefore the aim of the DOCTORS (Does OCT optimise the results of stenting?) study, Meneveau reported, was to investigate whether OCT-guided PCI would “impact on the functional result of angioplasty as assessed by FFR measure after stent implantation a lesion responsible for NSTE acute coronary syndrome”. He added that the study is the first randomised trial to compare OCT-guided PCI with angiography-guided PCI.
In DOCTORS, 240 patients with NSTE acute coronary syndrome eligible for PCI were randomised to undergo OCT-guided PCI (120) or angiography-guided PCI (120). In the OCT-guided PCI group, an “OCT run” was performed prior to the PCI to assess plaque morphology and presence of thrombus or calcifications and was performed after stent implantation to assess presence of thrombus, edge dissection, prolapse, optimal lesion coverage, stent malapposition, and underexpansion. Meneveau stated: “Several OCT runs could be performed. The run with a satisfactory result was considered as the final run.” The primary endpoint was the FFR value measured at the end of the procedure and safety endpoints included acute kidney injury and duration of the procedure (looking at fluoroscopy time, quantity of contrast used, and radiation dose delivered).
Significantly more patients in the OCT-guided group had evidence of thrombus and calcifications, according to the pre-PCI OCT run, than patients in the angiography-guided group: 69% and 45.8%, respectively, vs. 47% and 9% for the angiography-guided PCI group (p=0.0004 and p<0.0001, respectively). The higher rate of thrombus resulted in significantly more frequent use of GP IIb/IIIa inhibitors in the OCT-guided patients (53% vs. 35% for angiography-guided PCI; p=0.007), but otherwise the procedural strategies between groups were not significantly different.
According to the post OCT run, 32% of patients in the OCT-guided PCI group had stent malapposition. Furthermore, stent underexpansion (42% vs. 10.8%; p<0.0001) and edge dissection (37.5% vs. 4%; p<0.0001) were observed significantly more frequently in the OCT-guided PCI group. These findings led to greater procedural optimisation, including greater post-stent over dilation (43% vs. 12.5%; <0.0001), in this group compared with angiography-guided PCI group: 50% vs. 22.5%, respectively; p<0.0001. However, there were no significant differences between groups in the rate of additional stenting (27% vs. 17.5%; p=0.09) or total stent length (21.9±9.3 vs. 20.4±9; p=0.17).
In terms of the primary endpoint, the average FFR value was significantly higher in the OCT-PCI group: 0.94±0.04 vs. 0.92±0.05 for the angiography-guided PCI group (p=0.005). Also, the percentage of patients with post-PCI FFR >0.90 was significantly higher in the OCT-guided PCI group: 82.5% vs. 64.2%; p=0.0001. The improvement in FFR value observed in the OCT group was driven by optimization of stent expansion, which improved from an average of 78.9±12.4% post PCI to 84.1±7.3% post optimisation (p<0.0001 by the paired t test).
However, Meneveau reported that this benefit “was obtained at the cost of a longer procedure with higher fluoroscopy time and more contrast medium” but noted that there were no significant differences in the rate of type 4a myocardial infarction, procedural complications, or acute kidney injury between groups. He added “whether the improvement obtained in FFR will translate into clinical benefit remains to be determined,” commenting that additional prospective studies with clinical endpoints “are required before considering incorporating OCT guidance for standard use in patients with acute coronary syndromes”.
To coincide with its presentation at the ESC congress, the DOCTORS was simultaneously published in Circulation.