Identification of the type of stent with three-dimensional optical coherence tomography: the SPQR study

BACKGROUND

The ability of optical coherence tomography (OCT) to identify specific types of stent has never been systematically studied.

AIMS

The aim of this study was to test the accuracy of OCT imaging to identify patterns of stent platform and subsequently identify the type of stent implanted.

METHODS

Consecutive patients from six international centres were retrospectively screened, searching for OCT studies with metallic stents or scaffolds. The sample was analysed by two blinded operators, applying a dedicated protocol in four steps to identify the type of stent: 1) 3D and automatic strut detection (ASD), 2) 3D tissue view, 3) longitudinal view with ASD, 4) mode "stent only" and ASD.

RESULTS

A series of 212 patients underwent OCT in the study centres, finding 294 metallic stents or scaffolds in 146 patients. The protocol correctly identified 285 stents (96.9%, kappa 0.965), with excellent interobserver agreement (kappa 0.988). The performance tended to be better in recently implanted stents (kappa 0.993) than in stents implanted ≥3 months before (kappa 0.915), and in pullback speed 18 mm/s as compared with 36 mm/s (kappa 0.969 vs 0.940, respectively).

CONCLUSIONS

The type of stent platform can be accurately identified in OCT by trained analysts following a dedicated protocol, combining 3D-OCT, ASD and longitudinal view. This might be clinically helpful in scenarios of device failure and for the quantification of apposition. The blinding of analysts in OCT studies should be revisited.

A simplified formula to calculate fractional flow reserve in sequential lesions circumventing the measurement of coronary wedge pressure: The APIS-S pilot study

BACKGROUND

A simplified formula to calculate the predicted fractional flow reserve (FFR) in sequen-tial coronary stenosis without balloon inflation is hereby proposed.

METHODS

In patients with an indication for FFR and sequential coronary stenosis, FFR was recorded distally and between the lesions. The predicted FFR for each stenosis was calculated with a novel formu-la. While treating one of the lesions, wedge pressure was measured during balloon inflation to calculate Pijls' formula. FFR of the remaining lesion was finally recorded (measured FFR).

RESULTS

Forty patients were enrolled in the study, 4 (10.0%) had a distal FFR > 0.80 and were excluded from the main analysis. In the remaining 36 patients, the novel formula and Pijls' formula showed virtually absolute agreement (ICCa 0.999, R2 = 0.997 for the proximal lesion, R2 = 0.999 for the distal lesion, kappa 1.000, Se 100%, Sp 100%). The agreement between predicted and measured FFR was good (ICCa 0.820; 0.640-0.909, R2 = 0.717, intercept = 0.05, slope = 0.92, kappa 0.748, Se 75%, Sp 96%). In 19 (47.5%) cases the use of the formula enabled the operator to freely decide which lesion should be treated first, an option not available if the percutaneous coronary intervention (PCI) were guided by the largest pressure drop across each lesion.

CONCLUSIONS

The predicted FFR for each lesion in sequential coronary stenosis can be accurately calculated by a simplified formula circumventing the need for balloon inflation. This approach provides the operator upfront, with detailed information on physiology, thus having a potentially high impact on the corresponding PCI strategy.

A formula to calculate the contrast volume required for optimal imaging quality in optical coherence tomography with non-occlusive technique

BACKGROUND

Non-occlusive technique is universally accepted for acquisition of coronary optical coherence tomography (OCT), but the amount of contrast infused is still inconsistently calculated. Proposed herein, is an empirical formula for accurate contrast volume calculation.

METHODS

In an observational prospective study, contrast volume of consecutive patients undergoing OCT was either calculated with formula, or eyeballed based on manufacturer recommendations. The quality of pullback, defined as % of high quality cross-sections (CS) in the segment of interest (SOI), was analyzed by two independent operators and compared between groups, together with the amount of contrast per pullback.

RESULTS

Sixty patients (115 pullbacks, 4252 CS) were imaged using the formula, vs. 18 patients (22 pullbacks, 777 CS) eyeballing the contrast volume. The formula group used 18 mm/s as pullback speed more often (82.6% vs. 40.9%, p = 0.0001), but there were no significant differences between groups in SOI length or vessel imaged. The formula resulted in higher pullback quality than eyeballing (96.55% vs. 63.55%, p < 0.0001), interobserver agreement Kappa 0.903 (p < 0.0001), and tended to use less contrast per pullback than the eyeball group (13.03 mL vs. 14.55 mL, p = 0.057). After adjusting for pullback speed, SOI length and vessel in multivariate linear regression, the use of the formula significantly reduced the amount of contrast in 4.50 mL on average.

CONCLUSIONS

Optical coherence tomography acquisition with the non-occlusive technique can be substantially eased with the use of a novel formula to calculate the contrast volume required. This method optimises the quality of the images whilst reducing the amount of contrast per pullback.

Implantation of bioresorbable scaffolds under guidance of optical coherence tomography: Feasibility and pilot clinical results of a systematic protocol

BACKGROUND

Herein is hypothesised that a comprehensive optical coherence tomography (OCT)-guided implantation protocol for bioresorbable scaffolds (BRS) can improve expansion and apposition, thus resulting in better clinical outcomes, particularly in reducing thrombotic events.

METHODS

Patients considered suitable for BRS therapy in de novo coronary lesions underwent OCT. The predominant type of plaque was classified as lipidic, fibrous or calcific. Accordingly they underwent tailored plaque preparation. After proper sizing, BRS was deployed and final OCT was acquired. Post-dilation was performed only in cases of suboptimal deployment. Procedural and 12 month clinical follow-up is reported.

RESULTS

Twenty nine patients (41 lesions) who were considered clinically and angiographically suitable for BRS were enrolled, including challenging clinical scenarios such as ST-segment elevation myocardial infarction or CTOs. The OCT-guided protocol was feasible in 90.2% of the lesions: 14 (37.8%) lipidic, 11 (29.7%) fibrous, and 12 (32.4%) calcific. Three (8%) lesions classified as calcific were changed to treatment with metallic stent. BRS were implanted in 34 (91.9%) lesions, thereof 30 (88.2%) with optimal deployment in OCT. One (3.6%) periprocedural MI occurred, resulting in 3.6% target vessel failure and 0% scaffold thrombosis of any kind after a 12 month follow-up.

CONCLUSIONS

OCT-guided BRS implantation is feasible in 90.2% of de novo lesions and results in optimal expansion and apposition, correlating with 3.6% incidence of target vessel failure and 0% scaffold thrombosis at 12 m follow-up, probably due to better selection of lesions amenable for BRS treatment and to a possibility of tailoring intervention to the type of plaque. These encouraging pilot results require confirmation in larger clinical studies.

Very late stent thrombosis in everolimus-eluting stent with predisposing mechanical factors: Differential features

no abstract.