Impact of Intensive Low-Density Lipoprotein Cholesterol-Lowering Therapy on Coronary Artery Plaques in Acute Coronary Syndrome.

Acute coronary syndrome (ACS) is associated with a high incidence of unstable plaques beyond the culprit lesion, leading to early recurrence of cardiovascular events. Coronary computed tomography angiography (CCTA) can be used to noninvasively observe plaques throughout the coronary arteries. To evaluate the impact of intensive low-density lipoprotein cholesterol (LDL-C)-lowering therapy on quantitative changes in coronary plaque, assessed using CCTA in a study population with ACS. In total, 81 consecutive patients with ACS who underwent CCTA at discharge and at 1-year follow-up from April 2018 to March 2020 were analyzed. The patients were divided into 2 groups: those who achieved LDL-C <70 mg/100 ml and those who did not. Changes in plaque morphology within and between the 2 groups were compared using CCTA. A total of 198 vessels were analyzed. The calcified plaque volume was significantly increased in the LDL-C <70 group (65.8 ± 80.1 mm3 to 73.6 ± 83.7 mm3, p = 0.007), whereas no significant change was observed in the LDL-C ≥70 group (106.9 ± 161.7 mm3 to 105.7 ± 137.5 mm3, p = 0.552). Percent change in low-attenuation plaque volume in the LDL <70 group was significantly lower than in the LDL-C ≥70 group (17.2 ± 90.9% vs 84.4 ± 162.6%, p = 0.020). Receiver operating characteristic curve analysis demonstrated that the target LDL-C level for low-attenuation plaque volume regression was 64 mg/100 ml. In conclusion, noninvasive CCTA demonstrated that intensive LDL-C lowering in high-risk patients with ACS could potentially lead to plaque stabilization.

Efficacy of catheter ablation from the noncoronary aortic cusp of verapamil-sensitive atrial tachycardia arising near the atrioventricular node.

BACKGROUND: The efficacy of catheter ablation from the noncoronary aortic cusp (NCC) of verapamil-sensitive atrial tachycardia arising near the atrioventricular node (AVN-AT) has yet to be fully clarified. OBJECTIVE: We elucidated the determinant of an effective AVN-AT ablation from the NCC. METHODS: After identifying the earliest atrial activation site (EAAS) during tachycardia, the direction of the slow conduction zone (SCZ) of the reentry circuit was identified by demonstrating manifest entrainment in 26 patients with AVN-AT. Catheter ablation was initially performed from the NCC irrespective of the local activation time. If NCC ablation was ineffective, catheter ablation was performed targeting the SCZ entrance. Then the anatomical relationship between the SCZ and the successful ablation site was elucidated. RESULTS: NCC catheter ablation terminated AVN-AT in 14 patients (NCC group) but not in 12 (non-NCC group). Catheter ablation targeting the SCZ entrance terminated all non-NCC group ATs. The local activation time at the NCC relative to the EAAS did not differ between the NCC and non-NCC groups (10.1 ± 6.5 ms vs 11.2 ± 4.8 ms; P = .6333). The direction of the SCZ was posterior to the EAAS in all NCC group patients; however, it was posterolateral (n = 5) and lateral (n = 7) to the EAAS in the non-NCC group, suggesting that the SCZ existed in the direction of the NCC in the NCC group but was away from the NCC in the non-NCC group. CONCLUSION: A close proximity between the NCC and the SCZ of the reentry circuit, but not the local activation time at the NCC, determined the efficacy of NCC catheter ablation in AVN-ATs.

Verification of Coronary Computed Tomography-Derived Fractional Flow Reserve Measurement Site for Detection of Significant Coronary Artery Disease.

Background: The optimal site for measuring computed tomography (CT)-derived fractional flow reserve (FFRCT) to detect significant coronary artery disease (CAD) remains unknown. We investigated how diagnostic performance changes with FFRCT measurement site. Methods and Results: The diagnostic performance of FFRCT, measured 1-2 cm distal to the stenosis vs. a far-distal site, in detecting significant CAD with invasive fractional flow reserve ≤0.8 was evaluated in 254 diseased vessels from 146 patients with stable or suspected CAD diagnosed by coronary CT angiography. Receiver operating characteristic curve analysis revealed a significantly larger area under the curve for FFRCT measured 1-2 cm distal to the stenosis than at a far-distal site (0.829 vs. 0.791, respectively; P=0.0305). The rate of reclassification of positive FFRCT was 19% for measurements made 1-2 cm distal to the stenosis, and diagnostic accuracy for FFRCT 0.71-0.80 improved from 36% to 58% (P=0.0052). Vessel-based diagnostic accuracy of FFRCT 1-2 cm distal to the stenosis and at a far-distal site was 75% and 65%, respectively (P<0.0001), with corresponding sensitivity of 87% and 94% (P=0.0039), specificity of 60% and 29% (P<0.0001), a positive predictive value of 73% and 62% (P=0.028), and a negative predictive value of 78% and 79% (P=0.958). Conclusions: Our data suggest measuring FFRCT 1-2 cm distal to the stenosis has better diagnostic performance for detecting physiologically significant CAD.

Comparison of Diagnostic Performance of Fractional Flow Reserve Derived from Coronary Computed Tomographic Angiography Versus Single-Photon Emission Computed Tomographic Myocardial Perfusion Imaging.

Fraction flow reserve (FFR) derived from computed tomography (FFRCT) has been proposed to be an effective gatekeeper for invasive angiographic referral. The purpose of the present study is to examine the real-world diagnostic performance of FFRCT and myocardial perfusion imaging as well as to assess the utility of FFRCT as a gatekeeper for invasive coronary angiography in patients suspected of having obstructive coronary artery disease. Total of 146 consecutive patients underwent both single-photon emission computed tomography (SPECT) and invasive FFR were evaluated. An FFRCT value 1 to 2 cm distal to a stenosis ≤0.80 was defined as positive for ischemia and a summed stress score ≥2 or transient ischemic dilatation ≥1.2 were positive for ischemia with the invasive FFR value of <0.80 serving as the gold standard. The patient-based sensitivity of FFRCT was significantly higher than SPECT (91 vs 52%, p <0.001) and exhibited similar positive predictive value (82 vs 82%, p = 0.91). These trends were observed even in patients with multivessel and left main trunk disease and those with severe coronary calcification. In conclusion, our data suggest that FFRCT has higher diagnostic performance characteristics than SPECT and details the superior FFRCT analysis in detecting patients with hemodynamically significant coronary artery disease. Our results support the clinical utility of FFRCT analysis as a gatekeeper for invasive coronary angiography in clinical practice.

Comparison of the catheter ablation outcome in patients between targeting the entrance and exit of the reentry circuit in verapamil-sensitive atrial tachycardia originating from the atrioventricular-node vicinity.

Verapamil-sensitive atrial tachycardia originating from the atrioventricular node vicinity (AVN-AT) can be eliminated with radiofrequency energy (RF) deliveries targeting either the entrance or exit of its reentry circuit. However, the outcome of these different approaches has not been clarified well. Thus, we compared the catheter ablation outcome targeting the entrance of reentry circuit, identified by the entrainment method (Ent-Group; 21 patients) with that targeting the earliest atrial activation site (EAAS) during AT (Exit-Group; 16 patients). There was no significant difference in the tachycardia cycle length (441.4 ± 87.4 vs. 392.8 ± 64.8 ms, p = 0.0704) or distance from the His bundle (HB) site to the EAAS (6.5 ± 2.0 vs. 7.6 ± 1.8 mm, p = 0.0822) between the Ent- and Exit-Groups. However, distance from the successful ablation site to the HB site in the Ent-Group was significantly longer than that in the Exit-Group (13.4 ± 3.1 vs. 7.6 ± 1.8 mm, p < 0.0001), resulting in more frequent transient atrioventricular block episodes in the Exit-Group than Ent-Group (31.3 vs. 0%, p < 0.01). Initial ATs (AT1s) were terminated in all patients in both Groups. However, ATs accompanied by shifting in the EAAS (AT2) were induced more frequently in the Exit-Group than Ent-Group (50.0 vs. 14.3%, p < 0.02) after eliminating AT1. RF deliveries to the EAAS eliminated all AT2s. The number of RF deliveries was greater in the Exit-Group than Ent-Group (6.9 ± 3.3 vs. 3.9 ± 1.6, p < 0.001). In conclusion, RF ablation targeting the entrance sites can avoid AVN injury and is superior in reducing the number of RF deliveries and occurrence of different ATs than targeting the exit sites in the AVN-AT.

Determinants of insufficient improvement in fractional flow reserve following percutaneous coronary intervention.

Fractional flow reserve (FFR) has become an increasingly important index for decision making concerning coronary revascularization. It is commonly accepted that significant improvement in FFR following percutaneous coronary intervention (PCI) is associated with better symptomatic relief and a lower event rate. However, in lesions with insufficient FFR improvement, PCI may not improve prognosis. Leading to the observation that the clinical and angiographic characteristics associated with insufficient FFR improvement have not been fully explored. The purpose of this study was to investigate the factors associated with insufficient improvement in FFR. Using our own PCI database, established between January 2014 and December 2018, we identified 220 stable coronary artery lesions, which had been evaluated for both pre- and post-PCI FFR values. All 220 of these lesions were included in this study. The improvement in FFR (ΔFFR) was calculated in each lesion with the lowest quartile of ΔFFR being defined as the lowest ΔFFR group, and the other quartiles being defined as the intermediate-high ΔFFR group. The mean ΔFFR in the lowest and intermediate-high ΔFFR groups was 0.07 ± 0.02 and 0.21 ± 0.11, respectively. In multivariate logistic regression analysis, a short total stent length (10 mm increase: OR 0.67, 95% CI 0.47-0.96, P = 0.030), higher pre-PCI FFR (0.1 increase: OR 4.07, 95% CI 1.83-9.06, P = 0.001), in-stent restenosis (ISR) (OR 8.02, 95% CI 1.26-51.09, P = 0.028), myocardial infarction (MI) in the target vessel (OR 6.87, 95% CI 1.19-39.69, P = 0.031) and non-use of intravascular imaging (OR 0.35, 95% CI 0.12-0.99, P = 0.048) were significantly associated with the lowest ΔFFR group. The use of short stents, higher pre-PCI FFR values, ISR, MI in the target vessel, and non-use of intravascular imaging were significantly associated with insufficient FFR improvement. It was conversely suggested that full coverage and adequate dilatation of the lesions under an intravascular imaging guidance might contribute to an improvement in FFR.

Clinical impact of successful recanalization for chronic total occlusion: insights from stress myocardial perfusion imaging.

The clinical benefits of percutaneous coronary intervention (PCI) for chronic total occlusion (CTO) is still controversial. The purpose of this study is to assess the quantitative therapeutic benefits of successful PCI for CTO from the clinical data acquired by myocardial perfusion imaging (MPI). Consecutive 42 patients, who were successfully revascularized of CTO between August 2013 and March 2018, were examined. A stress MPI was performed before CTO PCI and at follow-up, and the changes in quantitative gated and perfusion single photon emission computed tomography parameters were examined. The follow-up interval was 18 ± 9 (median 14) months, during which 36 patients were maintained patency (patent CTO), while 6 were re-occluded (R/O CTO). The reduction in the % myocardial ischemia and the improvement in the ejection fraction were significantly higher in the patent CTO group than those in the R/O CTO group (67.5 ± 37.0% vs. - 56.4 ± 84.9%, p < 0.0001, 20.7 ± 49.8% vs. - 9.2 ± 20.6%, p = 0.0247, respectively). Interestingly, the improvements we observed were predominantly in the patients with LAD CTO rather than those with RCA or LCx CTO. Successful CTO PCI was able to reduce myocardial ischemia and improve the cardiac function when the patency after CTO PCI was maintained, with the most notable significance in the patients with LAD CTO.