Dynamic assessment of the left main-left circumflex bending angle: Implications for ostial left circumflex artery in-stent restenosis after successful two-stent PCI.

BACKGROUND: Two-stent techniques for percutaneous coronary intervention (PCI) on left main (LM) bifurcation (LMB) lesions are associated with an increased risk of in-stent restenosis (ISR) at left circumflex artery (LCx) ostium but the underlying mechanisms are incompletely understood. This study sought to investigate the association between cyclic change of LM-LCx bending angle (BALM-LCx) and the risk of ostial LCx ISR following two-stent techniques. METHODS: In a retrospective cohort of patients undergoing two-stent PCI for LMB lesions, BALM-LCx and distal bifurcation angle (DBA) were computed with 3-dimensional angiographic reconstruction. The analysis was performed both at end-diastole and end-systole, and the angulation change throughout the cardiac cycle was defined as the cardiac motion-induced angulation change (∆CAngle). RESULTS: A total of 101 patients were included. The mean pre-procedural BALM-LCx was 66.8 ± 16.1° at end-diastole and 54.1 ± 13.3° at end-systole with a range of 13.0 ± 7.7°. Pre-procedural ∆CBALM-LCx > 16.4° was the most relevant predictor of ostial LCx ISR (adjusted OR 11.58, 95% CI 4.04-33.19; p < 0.001). Post-procedural ∆CBALM-LCx > 9.8° and stent-induced diastolic BALM-LCx change > 11.6° were also related with ostial LCx ISR. DBA was positively correlated with BALM-LCx and showed a weaker association of pre-procedural ∆CDBA > 14.5° with ostial LCx ISR (adjusted OR 6.87, 95% CI 2.57-18.37; p < 0.001). CONCLUSIONS: Three-dimensional angiographic bending angle is a feasible and reproducible novel method for LMB angulation measurement. A large pre-procedural cyclic change of BALM-LCx was associated with an increased risk of ostial LCx ISR following two-stent techniques.

Functional Assessment of Myocardial Bridging With Conventional and Diastolic Fractional Flow Reserve: Vasodilator Versus Inotropic Provocation.

Background Functional assessment of myocardial bridging (MB) remains clinically challenging because of the dynamic nature of the extravascular coronary compression with a certain degree of intraluminal coronary reduction. The aim of our study was to assess performance and diagnostic value of diastolic-fractional flow reserve (d-FFR) during dobutamine provocation versus conventional-FFR during adenosine provocation with exercise-induced myocardial ischemia as reference. Methods and Results This prospective study includes 60 symptomatic patients (45 men, mean age 57±9 years) with MB on the left anterior descending artery and systolic compression ≥50% diameter stenosis. Patients were evaluated by exercise stress-echocardiography test, and both conventional-FFR and d-FFR in the distal segment of left anterior descending artery during intravenous infusion of adenosine (140 µg/kg per minute) and dobutamine (10-50 µg/kg per minute), separately. Exercise-stress-echocardiography test was positive for myocardial ischemia in 19/60 patients (32%). Conventional-FFR during adenosine and peak dobutamine had similar values (0.84±0.04 versus 0.84±0.06, P=0.852), but d-FFR during peak dobutamine was significantly lower than d-FFR during adenosine (0.76±0.08 versus 0.79±0.08, P=0.018). Diastolic-FFR during peak dobutamine was significantly lower in the exercise-stress-echocardiography test -positive group compared with the exercise- stress-echocardiography test -negative group (0.70±0.07 versus 0.79±0.06, P<0.001), but not during adenosine (0.79±0.07 versus 0.78±0.09, P=0.613). Among physiological indices, d-FFR during peak dobutamine was the only independent predictor of functionally significant MB (odds ratio, 0.870; 95% CI, 0.767-0.986, P=0.03). Receiver-operating characteristics curve analysis identifies the optimal d-FFR during peak dobutamine cut-off ≤0.76 (area under curve, 0.927; 95% CI, 0.833-1.000; P<0.001) with a sensitivity, specificity, and positive and negative predictive value of 95%, 95%, 90%, and 98%, respectively, for identifying MB associated with stress-induced ischemia. Conclusions Diastolic-FFR, but not conventional-FFR, during inotropic stimulation with high-dose dobutamine, in comparison to vasodilatation with adenosine, provides more reliable functional significance of MB in relation to stress-induced myocardial ischemia.

Coronary Flow Velocity Reserve Using Dobutamine Test for Noninvasive Functional Assessment of Myocardial Bridging.

BACKGROUND: It has been shown that coronary flow velocity reserve (CFVR) measurement by transthoracic Doppler echocardiography (TTDE) during dobutamine (DOB) provocation provides a more accurate functional evaluation of myocardial bridging (MB) compared to adenosine. However; the cut-off value of CFVR during DOB for identification of MB associated with myocardial ischemia has not been fully clarified. PURPOSE: This prospective study aimed to determine the cut-off value of TTDE-CFVR during DOB in patients with isolated-MB, as compared with stress-induced wall motion abnormalities (VMA) during exercise stress-echocardiography (SE) as reference. METHODS: Eighty-one symptomatic patients (55 males [68%], mean age 56 ± 10 years; range: 27-74 years) with the existence of isolated-MB on the left anterior descending artery (LAD) and systolic MB-compression ≥50% diameter stenosis (DS) were eligible to participate in the study. Each patient underwent treadmill exercise-SE, invasive coronary angiography, and TTDE-CFVR measurements in the distal segment of LAD during DOB infusion (DOB: 10-40 µg/kg/min). Using quantitative coronary angiography, both minimal luminal diameter (MLD) and percent DS at MB-site at end-systole and end-diastole were determined. RESULTS: Stress-induced myocardial ischemia with the occurrence of WMA was found in 23 patients (28%). CFVR during peak DOB was significantly lower in the SE-positive group compared with the SE-negative group (1.94 ± 0.16 vs. 2.78 ± 0.53; p < 0.001). ROC analyses identified the optimal CFVR cut-off value ≤ 2.1 obtained during high-dose dobutamine (>20 µg/kg/min) for the identification of MB associated with stress-induced WMA, with a sensitivity, specificity, positive and negative predictive value of 96%, 95%, 88%, and 98%, respectively (AUC 0.986; 95% CI: 0.967-1.000; p < 0.001). Multivariate logistic regression analysis revealed that MLD and percent DS, both at end-diastole, were the only independent predictors of ischemic CFVR values ≤2.1 (OR: 0.023; 95% CI: 0.001-0.534; p = 0.019; OR: 1.147; 95% CI: 1.042-1.263; p = 0.005; respectively). CONCLUSIONS: Noninvasive CFVR during dobutamine provocation appears to be an additional and important noninvasive tool to determine the functional severity of isolated-MB. A transthoracic CFVR cut-off ≤2.1 measured at a high-dobutamine dose may be adequate for detecting myocardial ischemia in patients with isolated-MB.

B-type Natriuretic Peptide and RISK-PCI Score in the Risk Assessment in Patients with STEMI Treated by Primary Percutaneous Coronary Intervention.

BACKGROUND: RISK-PCI score is a novel score for risk stratification of patients with ST elevation myocardial infarction (STEMI) treated by primary percutaneous coronary intervention (pPCI). The aim of this study was to evaluate the role of B-type natriuretic peptide (BNP) and the RISK-PCI score for early risk assessment in patients with STEMI treated by pPCI. METHODS: In 120 patients with STEMI treated by pPCI, BNP was measured on admission before pPCI. The primary end point was 30-day mortality. RESULTS: The ROC curve analysis revealed that the most powerful predictive factors of 30-day mortality were the plasma level of BNP ≥ 206.6 pg/mL with the sensitivity of 75% and specificity of 87.5% and the RISK-PCI score ≥ 5.25 with the sensitivity of 75% and specificity of 85.7%. Thirty-day mortality was 6.7%. After multivariate adjustment, admission BNP (≥ 206.6 pg/mL) (OR 2.952, 95% CI 1.072 - 8.133, p = 0.036) and the RISK-PCI score (≥ 5.25) (OR 2.284, 95% CI 1.140-4.578, p = 0.020) were independent predictors of 30-day mortality. The area under the ROC curve using the RISK-PCI score and BNP to detect mortality was 0.828 (p = 0.002) and 0.903 (p < 0.001), respectively. Addition of BNP to RISK-PCI score increased the area under the ROC to 0.949 (p < 0.001), but this increase measured by the c-statistic was not significant (p = 0.107). Furthermore, the significant improvement in risk reclassification (p < 0.001) and the integrated discrimination index (p = 0.042) were observed with the addition of BNP to RISK-PCI score for 30-day mortality. CONCLUSIONS: BNP on admission and the RISK-PCI score were the independent predictors of 30-day mortality in patients with the STEMI treated by pPCI. BNP in combination with the RISK-PCI score showed the way to more accurate risk assessment in patients with STEMI treated by pPCI.

Culprit lesion thrombus burden after manual thrombectomy or percutaneous coronary intervention-alone in ST-segment elevation myocardial infarction: the optical coherence tomography sub-study of the TOTAL (ThrOmbecTomy versus PCI ALone) trial.

AIMS: Manual thrombectomy has been proposed as a strategy to reduce thrombus burden during primary percutaneous coronary intervention (PCI) in patients with ST-segment elevation myocardial infarction (STEMI). However, the effectiveness of manual thrombectomy in reducing thrombus burden is uncertain. In this substudy of the TOTAL (ThrOmbecTomy versus PCI ALone) trial, we compared the thrombus burden at the culprit lesion using optical coherence tomography (OCT) in patients treated with thrombectomy vs. PCI-alone. METHODS AND RESULTS: The TOTAL trial (N = 10 732) was an international, multicentre, randomized trial of thrombectomy (using the Export catheter, Medtronic Cardiovascular, Santa Rosa, CA, USA) in STEMI patients treated with primary PCI. The OCT substudy prospectively enrolled 214 patients from 13 sites in 5 countries. Optical coherence tomography was performed immediately after thrombectomy or PCI-alone and then repeated after stent deployment. Thrombus quantification was performed by an independent core laboratory blinded to treatment assignment. The primary outcome of pre-stent thrombus burden as a percentage of segment analysed was 2.36% (95% CI: 1.73-3.22) in the thrombectomy group and 2.88% (95% CI: 2.12-3.90) in the PCI-alone group (P = 0.373). Absolute pre-stent thrombus volume was not different (2.99 vs. 3.74 mm(3), P = 0.329). Other secondary outcomes of pre-stent quadrants of thrombus, post-stent atherothrombotic burden, and post-stent atherothrombotic volume were not different between groups. CONCLUSION: Manual thrombectomy did not reduce pre-stent thrombus burden at the culprit lesion compared with PCI-alone. Both strategies were associated with low thrombus burden at the lesion site after the initial intervention to restore flow.

Is there a need for dedicated devices?

Although the provisional approach is recommended over a systematic two-stent approach in bifurcation lesions, an a priori two-stent approach may be considered in certain specific anatomies in a minority of cases. Virtual bench test and intravascular imaging studies have provided essential insights into the technical aspects of bifurcation stenting and led to recommendations on how to optimise both the provisional and the two-stent strategies. Dedicated bifurcation stents may further optimise the procedural and clinical outcomes of both strategies. However, randomised data are sparse and more randomised trials are needed to provide evidence as to whether these dedicated devices will indeed improve procedural and clinical outcomes.

The randomized physiologic assessment of thrombus aspiration in patients with acute ST-segment elevation myocardial infarction trial (PATA STEMI): study rationale and design.

INTRODUCTION: Routine thrombus aspiration is proposed to be superior to conventional primary percutaneous coronary intervention (PCI) in terms of improved myocardial perfusion, in patients with ST-segment elevation acute myocardial infarction (STEMI). However, myocardial perfusion after thrombus aspiration has not been evaluated by a quantitative, invasive method. We intend to determine whether manual thrombus aspiration in the infarct-related coronary artery increases myocardial perfusion assessed by index of microcirculatory resistance (IMR) compared with conventional primary PCI. STUDY DESIGN: PATA STEMI is a single-center, prospective, randomized trial with a planned inclusion of 128 patients with the first STEMI. Prior to coronary angiography, patients are randomly assigned to thrombus aspiration using the Eliminate aspiration catheter (Terumo Medical Supply, Japan) or to conventional primary PCI. After completion of primary PCI, IMR is determined both in infarct-related artery and in noninfarct-related arteries without critical stenoses. The primary end-point is a group mean value of IMR after thrombus aspiration compared with conventional primary PCI. Secondary end-points are myocardial perfusion grade, resolution of ST-segment elevation, enzymatic estimation of infarct size, left ventricular remodeling assessed by echocardiographic indices, and major adverse cardiac events rate at 1, 6, and 12 months. CONCLUSION: If manual thrombus aspiration significantly reduces microcirculatory resistance, thereby improving myocardial perfusion, it may become the routine strategy in primary PCI.