Prediction of fractional flow reserve using intravascular ultrasound.

BACKGROUND: In order to identify coronary lesions that cause myocardial ischaemia and require revascularisation, fractional flow reserve (FFR) is widely recommended. Recently, a method of estimating the FFR using morphological features measured by an imaging device was developed. However, all the previously developed methods are conducted offline, and such analysis takes approximately 10 minutes. AIMS: The aim of this present study was to develop an online measurement of the FFR using an intravascular ultrasound (IVUS) quantitative method (IQ-FFR). METHODS: This prospective, single-centre study included coronary lesions that met the following criteria: (1) presence of at least one stenosis (25-99%); (2) both IVUS and FFR measurement performed just before and after stent implantation, with the wire-derived FFR measured with a standard method; and (3) acquisition of clear images throughout the entire coronary branch. RESULTS: We developed an IVUS analysis system that automatically measures the cross-sectional area every 0.5 mm, and we calculated the IQ-FFR. In the prediction study, we calculated the IQ-FFR on the assumption that one stent of arbitrary length and diameter was implanted. After stent implantation, the wire-derived FFR was measured and compared with the calculated IQ-FFR. We compared 270 coronary lesions with stenosis rates of 32-99%. IQ-FFR measurements were strongly correlated with the wire-derived FFR (r=0.896). In the prediction study, the clinical accuracy of predicting whether the FFR would be greater or less than 0.80 after stent implantation was 87.5%. CONCLUSIONS: The IQ-FFR is a promising method to identify coronary lesions requiring revascularisation and to predict the FFR after stent implantation.

Wire bias modification with reverse orbital atherectomy for safer rotational atherectomy in calcified bifurcation.

Although debulking devices are very useful in modifying calcified plaques, their effectiveness is highly dependent on wire bias. In particular, in eccentric calcified bifurcation lesions, wire bias tends to be poor and needs to be corrected for adequate lesion preparation. A 67-year-old man was diagnosed with exertional angina pectoris. Coronary angiography showed a highly calcified eccentric lesion from the left main trunk to the left anterior descending artery. The patient refused coronary artery bypass surgery, therefore we decided to treat this complex bifurcation lesion with percutaneous coronary intervention. Initially, we performed reverse orbital atherectomy (OA) and sifted the guide wire position into the calcified plaque successfully. We continued with rotational atherectomy (RA) using a 2.0 mm burr and were able to obtain sufficient lumen without complications. Finally, the lesion was dilated with a cutting balloon and a drug-coated balloon to obtain a stent-like result. This case demonstrates that wire bias modification with reverse OA enables us to perform more aggressive and effective RA safely in eccentric calcified bifurcation lesions. This combination atherectomy can become an attractive approach in eccentric calcified bifurcation lesions. Learning objective: Atherectomy devices are helpful for lesion modification in calcified lesions but their effectiveness is highly dependent on wire bias. If the wire bias can be intentionally moved to an optimal position, it can be a very effective procedure in the treatment of calcified lesions. Wire bias modification by reverse ablation with orbital atherectomy that we have demonstrated enables subsequent aggressive rotational atherectomy and this combination atherectomy can be an attractive approach in eccentric calcified lesions.

Effects of Long-Term Carvedilol Therapy in Patients With ST-Segment Elevation Myocardial Infarction and Mildly Reduced Left Ventricular Ejection Fraction.

The benefits of long-term oral ß-blocker therapy in patients with ST-segment elevation myocardial infarction (STEMI) with mildly reduced left ventricular ejection fraction (LVEF; ≥40%) are still unknown. We sought to evaluate the efficacy of ß-blocker therapy in patients with STEMI with mildly reduced LVEF. In the CAPITAL-RCT (Carvedilol Post-Intervention Long-Term Administration in Large-Scale Randomized Controlled Trial), patients with STEMI with successful percutaneous coronary intervention with an LVEF of ≥40% were randomly assigned to carvedilol or no ß-blocker therapy. Among 794 patients, 280 patients had an LVEF of <55% at baseline (mildly reduced LVEF stratum), whereas 514 patients had an LVEF of ≥55% at baseline (normal LVEF stratum). The primary end point was a composite of all-cause death, myocardial infarction, hospitalization for acute coronary syndrome, and hospitalization for heart failure, and the secondary end point was a cardiac composite outcome: a composite of cardiac death, myocardial infarction, and hospitalization for heart failure. The median follow-up period was 3.7 years. The lower risk of carvedilol therapy relative to no ß-blocker therapy was not significant for the primary end point in either the mildly reduced or normal LVEF strata. However, it was significant for the cardiac composite end point in the mildly reduced LVEF stratum (0.82/100 person-years vs 2.59/100 person-years, hazard ratio 0.32 [0.10 to 0.99], p = 0.047) but not in the normal LVEF stratum (1.48/100 person-years vs 1.06/100 person-years, hazard ratio 1.39 [0.62 to 3.13], p = 0.43, p for interaction = 0.04). In conclusion, long-term carvedilol therapy in patients with STEMI with primary percutaneous coronary intervention might be beneficial for preventing cardiac-related events in those with a mildly reduced LVEF.

Diagnostic Accuracy of Artificial Intelligence-Based Angiography-Derived Fractional Flow Reserve Using Pressure Wire-Based Fractional Flow Reserve as a Reference.

BACKGROUND: Angiographic fractional flow reserve (angioFFR) is a novel artificial intelligence (AI)-based angiography-derived fractional flow reserve (FFR) application. We investigated the diagnostic accuracy of angioFFR to detect hemodynamically relevant coronary artery disease.Methods and Results: Consecutive patients with 30-90% angiographic stenoses and invasive FFR measurements were included in this prospective, single-center study conducted between November 2018 and February 2020. Diagnostic accuracy was assessed using invasive FFR as the reference standard. In patients undergoing percutaneous coronary intervention, gradients of invasive FFR and angioFFR in the pre-senting segments were compared. We assessed 253 vessels (200 patients). The accuracy of angioFFR was 87.7% (95% confidence interval [CI] 83.1-91.5%), with a sensitivity of 76.8% (95% CI 67.1-84.9%), specificity of 94.3% (95% CI 89.5-97.4%), and area under the curve of 0.90 (95% CI 0.86-0.93%). AngioFFR was well correlated with invasive FFR (r=0.76; 95% CI 0.71-0.81; P<0.001). The agreement was 0.003 (limits of agreement: -0.13, 0.14). The FFR gradients of angioFFR and invasive FFR were comparable (n=51; mean [±SD] 0.22±0.10 vs. 0.22±0.11, respectively; P=0.87). CONCLUSIONS: AI-based angioFFR showed good diagnostic accuracy for detecting hemodynamically relevant stenosis using invasive FFR as the reference standard. The gradients of invasive FFR and angioFFR in the pre-stenting segments were comparable.

Transformation of the Cardiovascular Clinics in Japan　- How to Overcome Crisis Due to Changes in the External Environment.

The first percutaneous coronary intervention (PCI) was performed in September 1977, and after 1980 this minimally invasive treatment was established in Japan. To deliver this treatment to a larger population, a number of cardiovascular clinics emerged across the country in the 2000s, and the number of PCI cases performed has been steadily increasing, to >250,000 cases per year. In the early 2000s, a single catheterization unit was profitable, if it performed a certain number of treatments and was adequately staffed without excessive capital investment. In the late 1990s, the price of a balloon catheter medical device used for PCI was approximately JPY300,000, although the price was reduced to JPY32,000, almost one-tenth in price, in the April 2022 revision of the National Health Insurance. The reimbursement of the mainstream drug-eluting stent has also decreased from JPY421,000, when it was first introduced, to JPY136,000 currently. In addition, the consumption tax and reforms in working hours will have a major impact on clinic management. We present a history of cardiovascular clinics in Japan and their present and future positions under the variable external environment.

Rewiring to the dissected branch along the jailed balloon (Real JAB technique)-A novel rewiring technique for the dissected branch in bifurcation lesion-case report.

Guidewire recrossing into the branch through the stent strut is difficult when that branch was injured or occluded after stenting in the true bifurcation lesion. A 72-year-old man with chronic total occlusion in both mid-left anterior descending coronary artery (LAD) and 2nd diagonal branch (D) was admitted to our hospital. We put a 2.25 × 38 mm drug-eluting stent from the LAD to the D with culotte stenting. However, the LAD occluded after stenting. Although we tried to recross, it was impossible because the guidewire migrated subintimal space which was caused by guidewire manipulation. So, we advanced a 2.25 mm balloon catheter on the 1st guidewire which had already been placed outside of the stent in the LAD, and inflated it at bifurcation to compress the subintimal space. Subsequently, we advanced another guidewire through the strut along the surface of the balloon catheter. Immediately after the deflation of the balloon, the guidewire slipped into the distal LAD without resistance. Large branch occlusion after stenting is a serious complication in true bifurcation treatment. Our new bailout technique is effective for recrossing a guidewire into the dissected branch to preserve it. .

Impact of Optimal Preparation Before Drug-Coated Balloon Dilatation for De Novo Lesion in Patients With Coronary Artery Disease.

BACKGROUND: Drug eluting stent (DES) remain several problems, including stent thrombosis, stent fracture and neoatherosclerosis. Stent-less Percutaneous coronary intervention (PCI) using a drug coated balloon (DCB) is a stent-less strategy, and several trials have supported the efficacy of DCB. However, the optimal preparation before using DCB was uncertain. The aim of this study was to investigate the optimal preparation for plaque oppression/debulking before DCB dilatation for de novo coronary artery lesion. METHODS: A total 936 patients were treated using DCB from 2014 to 2017 at our institution. Among them, we analyzed 247 patients who underwent PCI using DCB alone for de novo lesion. The primary end point of this study was target lesion failure (TLF). RESULTS: The area under the receiver operating characteristic (ROC) curve (AUC) was used to determine the optimal cutoff value of % plaque area to predict TLF. ROC curve analysis revealed plaque area ≥ 58.5% (AUC, 0.81) were associated with TLF. Eligible 188 patients were divided into 2 groups (plaque area ≥ 58.5% [n = 38] and <58.5% [n = 150]) according to IVUS data before using DCB. TLF was significantly higher in plaque area ≥ 58.5% group than in <58.5% group (P < 0.01). Multivariable analysis selected plaque area ≥ 58.5% as an independent predictor of TLF (hazard ratio 7.59, P < 0.01). CONCLUSIONS: Lesion preparation achieving plaque area < 58.5% was important in stent-less PCI using DCB.

The Effect of Aggressive Wire Recanalization in Calcified Atheroma and Dilatation (ARCADIA) Technique in Eccentric Calcified Lesion of No-stenting Zone.

PURPOSE: The endovascular approach for eccentric calcified lesions of the no-stenting zone is challenging. This study aimed to investigate the effect of a novel technique for these lesions. METHODS: We performed EVT for severe and eccentric calcified lesions using the technique, which is presented previously and named aggressive wire recanalization in calcified atheroma and dilatation (ARCADIA). In brief, a guidewire is passed to the residual lumen firstly. Next, another guidewire is advanced into and cross through the calcified plaque and returned to the distal original lumen with intravascular ultrasound (IVUS) guided. The calcified plaque is dilated by using a scoring-balloon or non-compliant balloon. RESULTS: Consecutive 14 peripheral artery disease patients with isolated and eccentric calcification in a no-stenting zone were treated using ARCADIA technique between January 2018 and March 2020. In IVUS data, lumen cross-section area was significantly increased from 5.2 ± 2.0 mm2 to 18.1 ± 6.9 mm2 (p < 0.01), lumen area was expanded roundly evaluating as symmetry index from 0.45 ± 0.09 to 0.81 ± 0.12 (p < 0.01). There were no distal embolization and perforation after ARCADIA technique. One-year target lesion revascularization occurred in only 2 cases. The primary patency of 1 year was 85.7%. CONCLUSION: ARCADIA technique is safe and appropriate, and can be 1 option to treat for eccentric calcified lesions of the no-stenting zone as an optimal wire crossing method.

Verification of the differences of scoring effect in current scoring balloons.

The characteristics of each scoring balloon seem to be different because material or configuration of scoring element in each device is unique. The aim of this study is to clarify the difference of scoring effect among 3 different scoring devices. We prepared 3 different scoring devices [Wolverine™ Cutting Balloon™ (CB), ScoreFlex™ NC (SF), NSE Alpha™ (NSE), n = 5 respectively. Balloon diameter is 3 mm and 2 types of silicone tubes with different elasticity [140 kPa (tube S) and 576 kPa (tube H), respectively. Inner diameter is 3 mm]. We dilated each balloon in each silicone tube with nominal pressure (NP) and 20 atmosphere (HP) and took a picture using a micro CT. We measured penetration depth of all scoring elements into silicone tube wall and calculated their percentage using the following formula; penetration depth/original scoring element height × 100. We also observed the deformation of scoring element during balloon inflation in each device. Scoring element of CB cut deeper into both tubes significantly than SF and NSE at both pressure (40.5% vs 25.1% and 16.8% at NP and 86.1% vs 33.5% and 29.1% at HP in tube S, p < 0.01, respectively, 62.6% vs 33.5% and 17.0% at NP and 93.3% vs 45.1% and 36.5% at HP in tube H, p < 0.01, respectively). Although no deformation of scoring element was recognized in CB, some deformations were observed in 50% of NSE and 40% of SF (p = 0.0377). Scoring balloon with sharp and firmly fixed scoring elements like CB may show definite scoring effect.

The importance of side branch preservation in the treatment of chronic total occlusions with bifurcation lesions.

OBJECTIVES: The aim of this study was to identify the predictive factors for suboptimal result in side branch (SB) in chronic total occlusion (CTO) bifurcation lesions and clinical outcomes of patients with suboptimal result in SB. BACKGROUND: There is little evidence on the optimal strategy for bifurcation lesions in CTO. METHODS: We retrospectively reviewed 314 consecutive bifurcation lesions in CTO with SB ≥ 2.5 mm in 3 hospitals from March 2010 to June 2018. Patients were divided into the two groups based on the suboptimal SB treatment (SST) and optimal SB treatment (OST) groups. The baseline characteristics, procedural and clinical outcomes were compared between the two groups. This study also evaluated the predictors of suboptimal result in SB. RESULTS: Suboptimal result in SB occurred in 47 cases. Presence of stenosis in SB, bifurcations located within the occluded segment and sub-intimal tracking at SB ostium was an independent predictor of suboptimal result in SB. The cumulative incidence of target lesion revascularization (TLR) in all lesions was not significantly different between the two groups, however, TLR in right coronary artery (RCA) was significantly higher in the SST group. In the Cox regression analysis, suboptimal result in SB in RCA and sub-intimal tracking were independent predictors of TLR for MB. In patients with bifurcations located within the occluded segment, usage of two-stent technique was significantly lower in the SST group. CONCLUSIONS: Meticulous procedures are required for SB preservation to improve not only SB prognosis but also MB, especially in RCA.

Stress Myocardial Perfusion Imaging Interpretation From the Viewpoint of Fractional Flow Reserve.

BACKGROUND: Myocardial perfusion imaging (MPI) and fractional flow reserve (FFR) are established approaches to the assessment of myocardial ischemia. Recently, various FFR cutoff values were proposed, but the diagnostic accuracy of MPI in identifying positive FFR using various cutoff values is not well established.Methods and Results:We retrospectively studied 273 patients who underwent stress MPI and FFR within a 3-month period. Results for FFR were obtained from 218 left anterior descending artery (LAD) lesions and 207 non-LAD lesions. Stress MPI and FFR demonstrated a good correlation in the detection of myocardial ischemia. However, the positive predictive value (PPV) of FFR for detecting MPI-positive lesions at the optimal FFR thresholds was insufficient (44% for LAD and 65% for non-LAD lesions). This was caused by a sharp drop in PPV at an FFR threshold of 0.7 or more. Notably, 41% of the lesions with normal MPI demonstrated FFRs <0.80. However, MPI-negative lesions had an extremely low lesion rate with FFR <0.65 (6%). Conversely, 78% and 41% of MPI-positive lesions had FFR <0.80 and <0.65, respectively. CONCLUSIONS: The data confirmed that decisions based on MPI are reasonable because MPI-negative patients have an extremely low rate of lesions with a FFR below the cutoff point for a hard event, and MPI-positive lesions include many lesions with FFR <0.65.

Persistence of the Postoperative Change in the Six-minute Walking Distance of Lung Cancer Patients with Chronic Obstructive Pulmonary Disease.

OBJECTIVES: The aim of this prospective follow-up study was to investigate the difference before and after surgery in the six-minute walking distance (6MD) of lung cancer patients with chronic obstructive pulmonary disease (COPD) and to examine the long-term effect of the change in 6MD in the early postoperative period. METHODS: This was a retrospective analysis of 25 COPD patients who underwent lung cancer surgery and perioperative rehabilitation in our department. Assessments of 6WD were carried out preoperatively and at 1, 3, and 6 months postoperatively. The changes in 6MD at 1, 3, and 6 months postoperatively compared with the preoperative value were designated the 1-month Δ6MD, the 3-month Δ6MD, and the 6-month Δ6MD, and the associations between them were investigated. RESULTS: The mean 6MD distance was 412.0±27.3 m (95% confidence interval) preoperatively, 369.0±33.8 m at 1 month, 395.6±32.2 m at 3 months, and 400.0±38.2 m at 6 months, with a significant difference between the preoperative and 1-month values (P<0.01). There were strong correlations between 1-month and 3-month Δ6MDs (r =0.74, P<0.0001) and between 1-month and 6-month Δ6MDs (r =0.88, P<0.0001). CONCLUSIONS: In lung cancer patients with COPD, the 1-month Δ6MD was strongly associated with both the 3-month Δ6MD and the 6-month Δ6MD. These findings suggest that the decrease in exercise tolerance of patients whose 6MD is low at 1 month postoperatively may be prolonged, and such patients may therefore be in greater need of postoperative outpatient rehabilitation.

Systematic Evaluation of High-Resolution Activation Mapping to Identify Residual Endocardial and Epicardial Conduction Across the Mitral Isthmus.

OBJECTIVES: This study sought to systematically evaluate the ability of a high-resolution mapping system (Rhythmia, Boston Scientific, Marlborough, Massachusetts) to rapidly and accurately localize residual endocardial and epicardial conduction after mitral isthmus (MI) ablation, facilitating MI block. BACKGROUND: Achieving conduction block across the mitral isthmus (MI) is challenging. METHODS: Fifty consecutive patients undergoing MI ablation after pulmonary vein isolation were enrolled. After initial endocardial radiofrequency (RF) ablation across the lateral MI, high-resolution activation mapping of the MI with simultaneous coronary sinus (CS) mapping was performed to verify block or localize residual conduction across the MI during left atrial (LA) appendage and CS pacing. Propagation maps were used to identify residual conduction across the MI as endocardial, via the CS or Marshall tract. RESULTS: In all 50 patients, after the initial endocardial ablation across the MI, repeat high-resolution mapping of the LA and CS was obtained (median: 3,329 mapped points; 4.0 min of mapping time). The initial endocardial MI ablation resulted in block in 9 of 50 patients (18%). In the remaining 41 patients, the propagation map identified residual conduction in 4 patterns: 1) only endocardial gap in 12 patients (29%); 2) only CS connection in 10 patients (24%); 3) both endocardial and CS connections in 14 patients (34%); and 4) Marshall tract connection in 5 patients (12%). In 8 patients, the propagation map revealed residual conduction, despite differential atrial pacing suggesting bidirectional block. Focal ablation at the identified residual conduction site (median: 0.7 min of RF) resulted in block in 49 of 50 (98%) patients. CONCLUSIONS: High-resolution propagation maps of the LA/CS rapidly and accurately localize residual endocardial and epicardial conduction across the MI. Focal ablation with short RF time at the identified gap(s) achieved complete block across MI in 98% of cases.

Determination of the Optimal Measurement Point for Fractional Flow Reserve Derived From CTA Using Pressure Wire Assessment as Reference.

BACKGROUND. For clinical decision making, it was recently recommended that values of fractional flow reserve (FFR) derived from coronary CTA (FFRCT) be measured 1-2 cm distal to the stenosis, given the potential for overestimation of ischemia when FFRCT values at far distal segments are used. Supporting data are, however, lacking. OBJECTIVE. The purpose of the present study was to evaluate the diagnostic performance of FFRCT values measured 1-2 cm distal to the stenosis and at more distal locations relative to invasive FFR values. METHODS. FFRCT and invasive FFR values for 365 vessels in 253 patients identified from the Assessing Diagnostic Value of Noninvasive FFRCT in Coronary Care (ADVANCE) registry were prospectively assessed. FFRCT values were measured 1-2 cm distal to the stenosis and at the pressure wire position and far distal segments. The diagnostic accuracy of FFRCT was assessed on the basis of the ROC AUC. The AUC of FFRCT was calculated using FFRCT as an explanatory variable and an invasive FFR of 0.80 or less as the dichotomous dependent variable. RESULTS. The AUC of FFRCT values measured 1-2 cm distal to the stenosis (0.85; 95% CI, 0.80-0.88) was higher (p = .002) than that of FFRCT values measured at far distal segments (0.80; 95% CI, 0.76-0.84) and similar (p = .16) to that of FFRCT values measured at the pressure wire position (0.86; 95% CI, 0.81-0.89). FFRCT values measured 1-2 cm distal to the stenosis and at far distal segments had sensitivity of 87% versus 92% (p = .003), specificity of 73% versus 42% (p < .001), PPV of 75% versus 59% (p < .001), and NPV of 86% versus 85% (p = .72), respectively. Subgroup analyses of lesions of the left anterior descending coronary artery, left circumflex coronary artery, and right coronary artery all showed improved specificity and PPV (all p < .005) for FFRCT values measured 1-2 cm distal to the stenosis compared with values measured at the pressure wire position. However, the AUC was higher for measurements obtained 1-2 cm distal to the stenosis versus those obtained at far distal segments, for left anterior descending coronary artery lesions (p < .001) but not for left circumflex coronary artery lesions (p = .27) or right coronary artery lesions (p = .91). CONCLUSION. The diagnostic performance of FFRCT values measured 1-2 cm distal to the stenosis was higher than that of FFRCT values measured at far distal segments and was similar to that of FFRCT values measured at the pressure wire position in evaluating ischemic status, particularly for left anterior descending coronary artery lesions. CLINICAL IMPACT. The present study supports recent recommendations from experts to use FFRCT measured 1-2 cm distal to the stenosis, rather than measurements obtained at far distal segments, in clinical decision making.

In vivo validation of resting full-cycle ratio and diastolic pressure ratio: simultaneous measurement with instantaneous wave-free ratio.

The diastolic pressure ratio (dPR) and resting full-cycle ratio (RFR) are considered to be almost identical to the instantaneous wave-free ratio (iFR) in the retrospective analysis of pooled data. The aim of this study was to investigate the direct comparison of iFR and these new resting indexes in real world practice. Two pressure wires were inserted and placed in the distal part of the same coronary artery. The measurement of the iFR and the other resting indexes was performed simultaneously. A total of 54 lesions from 23 patients were subject to physiological study. In 49 lesions, iFR and other resting indexes were also measured in hyperemic conditions. The general correlation between iFR and other resting indexes was excellent in both resting and hyperemic conditions (r2 = 0.99; mean difference - 0.001 ± 0.021; p < 0.001; and r2 = 0.99; mean difference - 0.012 ± 0.025; p < 0.001, respectively). This correlation was maintained in various subgroup analyses. A diagnostic change between iFR and other resting indexes occurred in three cases (3%) when a fixed cut-off point (≤ 0.89) was applied. There was no diagnostic change when a hybrid zone (0.86 ≤ iFR ≤ 0.93) was considered. The new resting indexes and iFR showed very high correlation in real world practice. A diagnostic change only occurred in three cases (3%) when a fixed cut-off point (≤ 0.89) was applied.

Current status of hybrid intravascular ultrasound and optical coherence tomography catheter for coronary imaging and percutaneous coronary intervention.

Both intravascular ultrasound (IVUS) and optical coherence tomography (OCT) play a crucial role in elucidating the pathophysiology of coronary artery disease (CAD) with the goal to improve patient outcomes of medical and/or interventional CAD management. However, no single intravascular imaging technique has been proven to provide complete and detailed evaluation of all CAD lesions due to some limitations. Although sequential use of multiple modalities may sometimes be performed, there may be issues related to risk, time, and cost. To overcome these problems, several hybrids involving dual-probe combined IVUS-OCT catheters have been developed. The aim of this review article is to demonstrate some limitations of stand-alone imaging devices for evaluation of CAD, summarize the advances in hybrid IVUS-OCT imaging devices, discuss the technical challenges, and present the potential value in the clinical setting, especially in patients receiving medical or interventional CAD management.