Impact of morphofunctional assessment with quantitative flow ratio and optical coherence tomography in patients with acute coronary syndromes.

BACKGROUND: Combining morphological and physiological evaluations might improve the risk stratification of patients who undergo percutaneous coronary intervention (PCI) for acute coronary syndrome (ACS) culprit lesions. AIMS: We aimed to investigate the clinical utility of morphofunctional evaluation after PCI for identifying ACS patients with increased risk of subsequent clinical events. METHODS: We retrospectively studied 298 consecutive ACS patients who had undergone optical coherence tomography (OCT)-guided PCI. We performed OCT-based morphological analysis and quantitative flow ratio (QFR)-based physiological assessment immediately after PCI. The non-culprit segment (NCS) was defined as the most stenotic untreated segment in the culprit vessel. The primary outcome was target vessel failure (TVF), a composite of cardiac death, target vessel-related myocardial infarction, and ischaemia-driven target vessel revascularisation. RESULTS: During a median follow-up period of 990 days, 42 patients experienced TVF. Cox regression analysis revealed that the presence of thin-cap fibroatheroma (TCFA) in the NCS and a low post-PCI QFR, or the presence of TCFA in the NCS and a high ΔQFR in the NCS (QFRNCS), were independently associated with TVF. The subgroup with TCFA in the NCS and a low post-PCI QFR had a significantly higher incidence of TVF (75%) than the other subgroups, and those with TCFA in the NCS and a high ΔQFRNCS had a significantly higher incidence of TVF (86%) than the other subgroups. The integration of TCFA in NCS, post-PCI QFR, and ΔQFRNCS with traditional risk factors significantly enhanced the identification of subsequent TVF cases. CONCLUSIONS: Combining post-PCI OCT and QFR evaluation may enhance risk stratification for ACS patients after successful PCI, particularly in predicting subsequent TVF.

Clinical impact of optical coherence tomography findings after drug-coated balloon treatment for patients with acute coronary syndromes.

BACKGROUND: Drug-coated balloon (DCB) became a potential treatment option for patients with acute coronary syndrome (ACS); however, factors associated with target lesion failure (TLF) remain uncertain. METHODS: This retrospective, multicentre, observational study included consecutive ACS patients who underwent optical coherence tomography (OCT)-guided DCB treatment. Patients were divided into two groups according to the occurrence of TLF, a composite of cardiac death, target vessel-related myocardial infarction, and ischemia-driven target lesion revascularisation. RESULTS: We enrolled 127 patients in this study. During the median follow-up period of 562 (IQR: 342-1164) days, 24 patients (18.9%) experienced TLF, and 103 patients (81.1%) did not. The cumulative 3-year incidence of TLF was 22.0%. The cumulative 3-year incidence of TLF was the lowest in patients with plaque erosion (PE) (7.5%), followed by those with rupture (PR) (26.1%) and calcified nodule (CN) (43.5%). Multivariable Cox regression analysis revealed that plaque morphology was independently associated with TLF on pre-PCI (percutaneous coronary intervention) OCT, and residual thrombus burden (TB) was positively associated with TLF on post-PCI OCT. Further stratification by post-PCI TB revealed a comparable incidence of TLF in patients with PR (4.2%) to that of PE if the culprit lesion had a smaller post-PCI TB than the cut-off value (8.4%). TLF incidence was high in patients with CN, regardless of TB size on post-PCI OCT. CONCLUSIONS: Plaque morphology was strongly associated with TLF for ACS patients after DCB treatment. Residual TB post-PCI might be a key determinant for TLF, especially in patients with PR.

The relationship between unique gut microbiome-derived lipid metabolites and subsequent revascularization in patients who underwent percutaneous coronary intervention.

BACKGROUND AND AIMS: Studies have recently revealed the linoleic acid metabolic pathway of Lactobacillus plantarum, the representative gut bacterium in human gastrointestinal tract, and the anti-inflammatory effects of metabolites in this pathway. However, no clinical trials have evaluated the association between these metabolites and revascularization in patients who underwent percutaneous coronary intervention (PCI). METHODS: We retrospectively reviewed patients who underwent PCI with subsequent revascularization or coronary angiography (CAG) without revascularization. Patients with frozen blood samples at the index PCI and revascularization or follow-up CAG were enrolled. RESULTS: Among 701 consecutive patients who underwent PCI, we enrolled 53 patients who underwent subsequent revascularization and 161 patients who underwent follow-up CAG without revascularization. Patients who underwent revascularization showed significantly lower plasma 10-oxo-octadecanoic acid (KetoB) levels (720.5 [551.6-876.5] vs. 818.4 [641.1-1103.6 pg/mL]; p = 0.01) at index PCI. Multivariate logistic regression analysis revealed that decreased plasma KetoB levels at the index PCI were independently associated with subsequent revascularization after PCI (odds ratio; 0.90 per 100 pg/mL increase, 95% confidence interval; 0.82-0.98). Additionally, in vitro experiments showed that the addition of purified KetoB suppressed the mRNA levels of IL-6 and IL-1ß in macrophages and IL-1ß mRNA in neutrophils. CONCLUSIONS: Plasma KetoB level at index PCI was independently associated with subsequent revascularization after PCI, and KetoB could act as an anti-inflammatory lipid mediator in macrophages and neutrophils. The assessment of gut microbiome-derived metabolites may help predict revascularization after PCI.

Prediction of the debulking effect of rotational atherectomy using optical frequency domain imaging: a prospective study.

This study determined the predictive accuracy of optical frequency domain imaging (OFDI) on debulking effects of rotational atherectomy (RA) and compared the predictive accuracy of OFDI catheter-based with Rota wire-based prediction methods. This prospective, single-center, observational study included 55 consecutive patients who underwent OFDI-guided RA. On pre-RA OFDI images, a circle, identical to the Rota burr was drawn at the center of the OFDI catheter (OFDI catheter-based prediction method) or wire (wire-based prediction method). The area overlapping the vessel wall was defined as the predicted ablation area (P-area). The actual ablated area (A-area) was measured by superimposing the OFDI images before and after RA. The overlapping P-area and A-area were defined as overlapped ablation area (O-area), and the predictive accuracy was evaluated by %Correct area (O-area/P-area) and %Error area (A-area - O-area/A-area). The median %Correct and %Error areas were 47.8% and 41.6%, respectively. Irrelevant ablation (low %Correct-/high % Error areas) and over ablation (high %Correct-/high % Error areas) were related to deep vessel injury and intimal flap outside the P-area. The predictive accuracy was better in the OFDI catheter-based prediction method than the wire-based prediction method in the cross sections where the OFDI catheter and wire came in contact. However, it was better in the latter than the former where the OFDI catheter and wire were not in contact. OFDI-based simulation of the RA effect is feasible though accuracy may be affected by the OFDI catheter and wire position. OFDI-based simulation of RA effect might reduce peri-procedural complications during RA.

Predictors of target lesion revascularisation after drug-eluting stent implantation for calcified nodules: an optical coherence tomography study.

BACKGROUND: Evidence of prognostic factors for stent failure after drug-eluting stent implantation for calcified nodules (CNs) is limited. AIMS: We aimed to clarify the prognostic risk factors associated with stent failure among patients who underwent drug-eluting stent implantation for CN lesions using optical coherence tomography (OCT). METHODS: This retrospective, multicentre, observational study included 108 consecutive patients with CNs who underwent OCT-guided percutaneous coronary intervention (PCI). To evaluate the quality of CNs, we measured their signal intensity and analysed the degree of signal attenuation. All CN lesions were divided into dark or bright CNs according to the half width of signal attenuation, greater or lower than 332, respectively. RESULTS: During the median follow-up period of 523 days, 25 patients (23.1%) experienced target lesion revascularisation (TLR). The 5-year cumulative incidence of TLR was 32.6%. Multivariable Cox regression analysis revealed that younger age, haemodialysis, eruptive CNs, dark CNs assessed by pre-PCI OCT, disrupted fibrous tissue protrusions, and irregular protrusions assessed by post-PCI OCT were independently associated with TLR. The prevalence of in-stent CNs (IS-CNs) observed at follow-up OCT was significantly higher in the TLR group than in the non-TLR group. CONCLUSIONS: Factors such as younger age, haemodialysis, eruptive CNs, dark CNs, disrupted fibrous tissue, or irregular protrusions were independently related to TLR in patients with CNs. The high prevalence of IS-CNs might indicate that the main cause of stent failure implanted in CN lesions could be the recurrence of CN progression in the stented segment.

Angioscopic Comparison of Early- and Mid-Term Vascular Responses Following Treatment of ST-Elevation Acute Myocardial Infarction With Biodegradable vs. Durable Polymer Everolimus-Eluting Stents　- A Prespecified Subanalysis of the MECHANISM AMI RCT.

BACKGROUND: The vessel healing process after implantation of biodegradable polymer (BP) and durable polymer (DP) everolimus-eluting stent (EES) in ST-elevation myocardial infarction (STEMI) lesions remains unclear.Methods and Results: We conducted a multicenter prospective randomized controlled trial to compare early (2 weeks) and mid-term (12 months) vascular responses after implantation of BP-EES vs. DP-EES in STEMI patients. In this prespecified subanalysis, serial coronary angioscopy (CAS) analysis was performed in 15 stents in the BP-EES arm (n=10 patients) and 14 stents in the DP-EES arm (n=10 patients). At the 2-week follow-up, there was no significant difference in the estimated marginal means of the neointimal coverage grade (primary endpoint) between the 2 arms (mean [±SE] 0.00±0.00 in both arms; P>0.999). There were no significant differences between the BP-EES and DP-EES groups in the yellow color grade (1.046±0.106 vs. 0.844±0.114, respectively; P=0.201) or the presence of thrombus (77.8% vs. 88.8%, respectively; P=0.205). At 12 months, competent strut coverage, defined as yellow color grade ≤1, no thrombus, and a neointimal coverage grade ≥1 was achieved more frequently in the BP-EES than DP-EES arm (85.2% vs. 53.1%; adjusted odds ratio 2.11 [95% confidence interval 1.26-3.53]; P=0.023). CONCLUSIONS: Neointimal coverage 2 weeks after implantation of BP-EES and DP-EES in STEMI lesions was comparable on CAS evaluation. However, at 1 year, BP-EES was independently associated with competent strut coverage.

Optical Coherence Tomography Fractional Flow Reserve and Cardiovascular Outcomes in Patients With Acute Coronary Syndrome.

BACKGROUND: Optical coherence tomography-derived fractional flow reserve (OCT-FFR) correlates strongly with wire-based FFR; however, its clinical significance remains uncertain. OBJECTIVES: This study sought to investigate the relationship between post-percutaneous coronary intervention (PCI) OCT-FFR and long-term clinical outcomes in acute coronary syndrome (ACS). METHODS: This retrospective, multicenter, observational cohort study included consecutive patients with ACS who underwent OCT-guided emergency PCI. We analyzed post-PCI OCT images and calculated OCT-FFR to identify independent factors associated with target vessel failure (TVF) after PCI. RESULTS: Among 364 enrolled patients, 54 experienced TVF during a median follow-up of 36 (IQR: 26-48) months. Vessel-level OCT-FFR was significantly lower in the TVF group than in the non-TVF group (0.87 vs 0.94; P < 0.001). In the multivariable Cox regression analysis, low vessel-level OCT-FFR (HR per 0.1 increase: 0.38; 95% CI: 0.29-0.49; P < 0.001) and thin-cap fibroatheroma in the nonculprit lesion were independently associated with TVF. The TVF rate of vessels with both low vessel-level OCT-FFR (<0.90) and thin-cap fibroatheroma in the nonculprit lesion was 8.1 times higher than that of all other vessels (69.3% vs 12.4%; HR: 8.13; 95% CI: 4.33-15.25; log-rank P < 0.001). Furthermore, adding vessel-level OCT-FFR to baseline characteristics and post-PCI OCT findings improved discriminatory and reclassification ability in identifying patients with subsequent TVF. CONCLUSIONS: Vessel-level OCT-FFR was an independent factor associated with TVF after PCI in patients with ACS. Adding the OCT-FFR measurement to post-PCI OCT findings may enable better discrimination of patients with subsequent TVF after PCI for ACS. (Relationship between Intracoronary Optical Coherence Tomography Derived Virtual Fractional Flow Reserve and cardiovascular outcome on Acute coronary syndrome; UMIN000043858).

Real-world clinical outcomes of percutaneous transluminal septal myocardial ablation for patients with drug-refractory hypertrophic obstructive cardiomyopathy: results from a retrospective multicenter registry of non-high-volume centers.

Percutaneous transluminal septal myocardial ablation (PTSMA) is a well-established interventional therapy for drug-refractory hypertrophic obstructive cardiomyopathy (HOCM) as an alternative to surgical myectomy. Although guidelines recommend that PTSMA should be performed in institutions with extensive experience, it is not centralized to such high-volume centers in real-world clinical practice. Thus, this study aimed to assess the feasibility of PTSMA in non-high-volume centers. We retrospectively examined patients with HOCM who underwent PTSMA between August 2012 and May 2020 at four institutions that experienced fewer than 20 cases of PTSMA procedures. The primary clinical endpoint was a composite of safety (all-cause death, electrical defibrillation for ventricular tachycardia or fibrillation, cardiac tamponade, permanent pacemaker implantation, and repeated interventions) and efficacy endpoints (repeated interventions [PTSMA or surgical myectomy]). Fifty-eight consecutive patients were enrolled. During the 30-day follow-up, no major clinical adverse events were noted except three patients (5.2%) requiring permanent pacemaker implantation for complete atrioventricular block. The percentage of patients with New York Heart Association functional class 1 or 2 significantly increased from 8.6 to 100% (p < 0.001). In the Cox proportional hazard model, left ventricular outflow tract pressure gradient at rest ≥ 30 mmHg (hazard ratio [HR] 6.56; 95% confidence interval [CI] 1.44-29.90; p = 0.015) and mitral regurgitation grade ≥ 3 (HR 10.75; 95% CI 1.81-63.79; p = 0.009) at the 30-day follow-up were associated with a composite of major clinical adverse events. The current study demonstrated that 58 patients who underwent PTSMA in non-high-volume centers had favorable 30-day clinical outcomes, with a primary composite endpoint rate of 5.2%. A prospective study with a larger sample size and longer follow-up is warranted to verify the safety and efficacy of PTSMA in non-high-volume centers.

Cholesterol uptake capacity: A new measure of high-density lipoprotein functionality as a predictor of subsequent revascularization in patients undergoing percutaneous coronary intervention.

BACKGROUND AND AIMS: High-density lipoprotein (HDL) functionality is an important determinant of coronary artery disease (CAD) development. We recently developed cholesterol-uptake capacity (CUC), a rapid cell-free assay system that directly evaluates the capacity of HDL to accept additional cholesterol. We aimed to evaluate the association between CUC and revascularization in patients who have undergone percutaneous coronary intervention (PCI). METHODS: We retrospectively reviewed patients who underwent PCI with subsequent revascularization or coronary angiography (CAG) without revascularization. The patients who had frozen blood samples for which CUC were measurable at the index PCI and follow-up were enrolled. RESULTS: We finally enrolled 74 patients who underwent subsequent revascularization and 183 patients who underwent follow-up CAG without revascularization. The serum CUC level at the index PCI was significantly lower in the revascularization group than that in the non-revascularization group (84.3 [75.2-98.9] vs. 92.0 [81.6-103.3 A U.]; p = 0.004). Multivariate logistic regression analysis revealed that decreased serum CUC level at the index PCI was independently associated with subsequent revascularization (odds ratio, 0.98; 95% confidence interval, 0.969-1.000). After adjusting for 16 cardiovascular risk factors, the serum CUC level at the index PCI and follow-up and the absolute change in serum CUC level from the index PCI to follow-up were significantly lower in the revascularization group than those in the non-revascularization group. CONCLUSIONS: Serum CUC level at index PCI was independently associated with subsequent revascularization after PCI. Continuous assessment of HDL functionality by CUC might help predict subsequent revascularization after PCI.

Predictor analysis of 1-year restenosis after percutaneous transluminal angioplasty for femoropopliteal stenotic lesions using intravascular ultrasound.

This retrospective, single-center study evaluated the patency rate and predictors of restenosis after percutaneous transluminal angioplasty (PTA) for femoropopliteal stenotic lesions using intravascular ultrasound. We assessed 78 de novo femoropopliteal stenotic lesions (64 patients; mean age, 73.6 ± 9.4 years; average lesion length, 59.8 mm) that underwent PTA under intravascular ultrasound guidance. The primary endpoint was 1-year primary patency. The 1-year primary patency rate was 63%. The frequency of insulin use was significantly greater (44% vs. 12%, p = 0.005), and lesions were significantly longer (77.8 mm vs. 49.2 mm, p = 0.047) in the restenosis group than in the non-restenosis group. The pre-intervention reference lumen area and minimum lumen area (MLA) were significantly smaller in the restenosis group (reference lumen area: 19.7 ± 6.7 mm2 vs. 23.7 ± 7.4 mm2, p = 0.017; MLA 3.9 ± 2.8 mm2 vs. 5.7 ± 3.9 mm2, p = 0.026; respectively). The MLA was significantly smaller and the maximum angle of dissection was significantly larger in the restenosis group (MLA 9.3 mm2 vs. 12.3 mm2, p = 0.013; maximum angle of dissection: 104.1° vs. 69.6°, p = 0.003; respectively) among post-intervention parameters. Multivariate analysis revealed that the independent predictors of 1-year restenosis were the large post-intervention maximum angle of dissection and insulin use. Per receiver operating curve analysis, the best cut-off value of the post-intervention maximum angle of dissection that predicted 1-year restenosis was 70.2° (sensitivity 72.4%, specificity 63.3%, area under the curve 0.70, p = 0.004). In conclusion, the 1-year primary patency rate after PTA for relatively short stenotic femoropopliteal lesions was 63%. The large post-intervention maximum angle of dissection, measured using intravascular ultrasound, and insulin use were independent predictors of restenosis after PTA.

Techniques for reducing air bubble intrusion into the left atrium during radiofrequency catheter and cryoballoon ablation procedures: An ex vivo study with a high-resolution camera.

BACKGROUND: Air embolisms are serious complications during catheter ablation procedures. OBJECTIVES: The aims of the present study were to determine when air bubbles enter the left atrium (LA) during catheter ablation procedures and to identify techniques that reduce air bubble intrusion. METHODS: An ex vivo study was performed to monitor air bubbles using a silicone heart model and a high-resolution camera. In total, 280 radiofrequency catheter and cryoballoon ablation processes were tested. RESULTS: Small and large air bubbles were often observed during catheter ablation processes. Many small air bubbles arose during sheath flushing at fast speeds (15 mL/2 s) (median bubble number [quartiles]: 35 [20-53] for SL0, 35 [23-44] for Agilis, and 98 [91-100] for FlexCath) and during initial cryoballoon inflation/freezing/deflation (34 [22-47]). Large (≥1.5 mm) air bubbles were observed during Lasso catheter insertion (1 [0-1]), cryoballoon insertion (2 [1-2]), and initial inflation/freezing/deflation (1 [1-3]). Massive air bubbles were observed during Optima catheter insertion into the sheath using an inserter (10 [2-15]). Sheath flushing at slow speeds (15 mL/5 s) significantly reduced the number of air bubbles. Before cryoballoon insertion, temporary balloon inflation and air bubble removal from the inflated surface were most effective in reducing air bubble intrusions. Optima catheter insertion without an inserter significantly reduced large air bubble intrusion. CONCLUSION: Air bubbles entered the LA at specific times. Techniques such as sheath flushing at slow speeds, temporary cryoballoon inflation before insertion, inserting the Optima catheter without an inserter, and avoidance of negative pressure in the LA could reduce air bubble intrusion.