Assessment of Clinical, Electrocardiographic, and Physiological Relevance of Diagonal Branch in Left Anterior Descending Coronary Artery Bifurcation Lesions

Definitions and Standardized Endpoints for Treatment of Coronary Bifurcations

The Bifurcation Academic Research Consortium (Bif-ARC) project originated from the need to overcome the paucity of standardization and comparability between studies involving bifurcation coronary lesions. This document is the result of a collaborative effort between academic research organizations and the most renowned interventional cardiology societies focused on bifurcation lesions in Europe, the United States, and Asia. This consensus provides standardized definitions for bifurcation lesions; the criteria to judge the side branch relevance; the procedural, mechanistic, and clinical endpoints for every type of bifurcation study; and the follow-up methods. Considering the complexity of bifurcation lesions and their evaluation, detailed instructions and technical aspects for site and core laboratory analysis of bifurcation lesions are also reported. The recommendations included within this consensus will facilitate pooled analyses and the effective comparison of data in the future, improving the clinical relevance of trials in bifurcation lesions, and the quality of care in this subset of patients.

New ECG Algorithm for the Prediction of Culprit Vessel in Acute Myocardial Infarction Involving Lateral Part of the Ventricle: Ilkay Classification

Background

Isolated lateral myocardial infarction sometimes does not meet ST-segment elevation myocardial infarction (STEMI) criteria according to contiguous leads. This condition could cause late diagnosis and the need for revascularization therapy.

Aim

To accurately predict the occlusion of lateral surface of the left ventricle, we defined a new electrocardiogram (ECG) algorithm by using angiographic and electrocardiographic correlations.

Methods

This was a retrospective, multicenter observational study. The study population consisted of 200 patients with STEMI affecting lateral surface of myocardium, between 2021 and 2022. According to the coronary angiography results, we identified 74 eligible patients for study protocol. The study patients were divided into two groups: isolated DB (14 patients) or circumflex obtuse marginal group (60 patients).

Results

ST depression in lead V2 had high positive predictive values for the prediction of obtuse marginal occlusion (positive predictive values (PPV), 100%; negative predictive value (NPV), 90%). ST elevation in V2 in ECG, in conjunction with ST depression in lead III had high positive predictive values for prediction of diagonal branch of LAD. Moreover, the presence of hyperacute T wave (≥10 mm) in lead V2 and ≥2 mm ST depression in lead III had large diagonal branch of LAD (PPV, 98%; NPV, 100%). However, <10 mm T wave in lead V2 and <2 mm ST depression in lead III had small diagonal branch of LAD.

Conclusion

We comprehensively classified the lateral STEMI definition through new electrocardiographic scheme as Ilkay classification, whereby we could accurately predict infarct-related artery and its occlusion level in lateral myocardial infarction.

Physiological Approach for Coronary Artery Bifurcation Disease: Position Statement by Korean, Japanese, and European Bifurcation Clubs

Coronary artery bifurcation lesions are frequently encountered in cardiac catheterization laboratories and are associated with more complex procedures and worse clinical outcomes than nonbifurcation lesions. Therefore, anatomical and physiological assessment of bifurcation lesions before, during, and after percutaneous coronary intervention is of paramount clinical importance. Physiological assessment can help interventionalists appreciate the hemodynamic significance of coronary artery disease and guide ischemia-directed revascularization. However, it is important to understand that the physiological approach for bifurcation disease is more important than simply using physiological indexes for its assessment. This joint consensus document by the Korean, Japanese, and European bifurcation clubs presents the concept of a physiological approach for coronary bifurcation lesions, as well as current knowledge, practical tips, pitfalls, and future directions of applying physiological indexes in bifurcation percutaneous coronary intervention. This document aims to guide interventionalists in performing appropriate physiology-based assessments and treatment decisions for coronary bifurcation lesions.

Definitions and Standardized Endpoints for Treatment of Coronary Bifurcations

The Bifurcation Academic Research Consortium (Bif-ARC) project originated from the need to overcome the paucity of standardization and comparability between studies involving bifurcation coronary lesions. This document is the result of a collaborative effort between academic research organizations and the most renowned interventional cardiology societies focused on bifurcation lesions in Europe, the United States, and Asia. This consensus provides standardized definitions for bifurcation lesions; the criteria to judge the side branch relevance; the procedural, mechanistic, and clinical endpoints for every type of bifurcation study; and the follow-up methods. Considering the complexity of bifurcation lesions and their evaluation, detailed instructions and technical aspects for site and core laboratory analysis of bifurcation lesions are also reported. The recommendations included within this consensus will facilitate pooled analyses and the effective comparison of data in the future, improving the clinical relevance of trials in bifurcation lesions, and the quality of care in this subset of patients.

Side Branch is the Main Determinant Factor of Bifurcation Lesion Complexity: Critical Review with a Proposal Based on Single-centre Experience

Although bifurcation stenting can be often managed with a simple provisional approach, in some settings, more complex techniques are appropriate. Based on our clinical experience and on data from literature, we propose a simple algorithm that may assist in selecting cases for elective double stenting. We found that, when the side branch is of adequate dimensions and affected by significant disease (longer than 10 mm and/or with presence of ostial calcifications), double stenting is associated with a lower incidence of adverse events, compared with provisional stenting.

Ventricular fibrillation storm after revascularization of chronic total occlusion of the left anterior descending artery: is this reperfusion arrhythmia?

Electrical storm is a life-threatening emergency condition defined as three or more episodes of ventricular tachycardia or ventricular fibrillation (VF) within 24 hours requiring anti-tachycardia therapy, electrical cardioversion, or defibrillation. However, studies of the incidence of electrical storm after chronic total occlusion-percutaneous coronary intervention (CTO-PCI) are limited,⁷ and post-procedural VF after revascularization of CTO has not been described. The purpose of this article was to present a case of post-operative VF electrical storm after revascularization of CTO of the left anterior descending (LAD) artery to determine whether the electrical storm was caused by reperfusion arrhythmia or compromise of either branch vessels or the collateral circulation during intervention.

Contemporary Management of Isolated Ostial Side Branch Disease: An Evidence-based Approach to Medina 001 Bifurcations

The optimal management of bifurcation lesions has received significant interest in recent years and remains a matter of debate among the interventional cardiology community. Bifurcation lesions are encountered in approximately 21% of percutaneous coronary intervention procedures and are associated with an increased risk of major adverse cardiac events. The Medina classification has been developed in an attempt to standardise the terminology when describing bifurcation lesions. The focus of this article is on the management of the Medina 0,0,1 lesion (‘Medina 001’), an uncommon lesion encountered in <5% of all bifurcations. Technical considerations, management options and interventional techniques relating to the Medina 001 lesion are discussed. In addition, current published data supporting the various proposed interventional treatment strategies are examined in an attempt to delineate an evidence-based approach to this uncommon lesion.

Asia Pacific consensus document on coronary bifurcation interventions

Coronary bifurcation intervention is common but complex. Progress in this field has been made in recent years with considerable contribution from the Asia Pacific (APAC) region. However, the standard of practice varies across the APAC region due to differences in culture, socioeconomic state and healthcare set-up. Practice may also differ from the rest of the world. Hence, a panel of experts was invited to discuss topics relevant to bifurcation intervention in order to make a concerted effort to achieve consensus that is applicable within the region and in line with available evidence.

Anatomical attributes of clinically relevant diagonal branches in patients with left anterior descending coronary artery bifurcation lesions

AIMS

This study aimed to investigate the anatomical attributes determining myocardial territory of diagonal branches and to develop prediction models for clinically relevant branches using myocardial perfusion imaging (MPI) and coronary CT angiography (CCTA).

METHODS AND RESULTS

The amount of ischaemia and subtended myocardial mass of diagonal branches was quantified using MPI by percent ischaemic myocardium (%ischaemia) and CCTA by percent fractional myocardial mass (%FMM), respectively. In 49 patients with isolated diagonal branch disease, the mean %ischaemia by MPI was 6.8±4.0%, whereas in patients with total occlusion or severe disease of all diagonal branches it was 8.4±3.3%. %ischaemia was different according to the presence of non-diseased diagonal branches and dominant left circumflex artery (LCx). In the CCTA cohort (306 patients, 564 diagonal branches), mean %FMM was 5.9±4.4% and 86 branches (15.2%) had %FMM ≥10%. %FMM was different according to LCx dominance, number of branches, vessel size, and relative dominance between two diagonal branches. The diagnostic accuracy of prediction models for %FMM ≥10% based on logistic regression and decision tree was 0.92 (95% CI: 0.85-0.96) and 0.91 (95% CI: 0.84-0.96), respectively. There was no difference in the diagnostic performance of models with and without size criterion.

CONCLUSIONS

LCx dominance, number of branches, vessel size, and dominance among diagonal branches determined the myocardial territory of diagonal branches. Clinical application of prediction models based on these anatomical attributes can help to determine the clinically relevant diagonal branches in the cardiac catheterisation laboratory.

CLINICAL TRIAL REGISTRATION

NCT03935542

The diagonal branches and outcomes in patients with anterior ST- elevation myocardial infarction

BACKGROUND

The management of diagonal branch (D) occlusion is still controversary. The association between the flow loss of D and the prognosis remains unclear. We aim to detect the impact of D flow on cardiac function and clinical outcomes in patients with anterior ST-segment elevation myocardial infarction (STEMI).

METHODS

Patients with anterior STEMI undergoing primary percutaneous coronary intervention (PCI) at our clinic between October 2015 and October 2018were reviewed. Anterior STEMI due to left anterior descending artery (LAD) occlusion with or without loss of the main D flow (TIMI grade 0-1 or 2-3) was enrolled in the analysis. The short- and long-term incidence of major adverse cardiac events (MACEs, a composite of all-cause death, target vessel revascularization and reinfarction) and left ventricular ejection fraction (LVEF) were analyzed.

RESULTS

A total of 392 patients (mean age of 63.9 years) with anterior STEMI treated with primary PCI was enrolled in the study. They were divided into two groups, loss (TIMI grade 0-1, n = 69) and no loss (TIMI grade2-3, n = 323) of D flow, before primary PCI. Compared with the group without loss of D flow, the group with loss of D flow showed a lower LVEF post PCI (41.0% vs. 48.8%, p = 0.003). Meanwhile, loss of D flow resulted in the higher in-hospital, one-month, and 18-month incidence of MACEs, especially in all-cause mortality (all p < 0.05). Landmark analysis further indicated that the significant differences in 18-month outcomes between the two groups mainly resulted from the differences during the hospitalization. In addition, multivariate Cox proportional hazards analysis found that D flow loss before primary PCI was independent factor predicting short- and long-term outcomes in patients with anterior STEMI.

CONCLUSION

Loss of the main D flow in anterior STEMI patients was independently associated with the higher in-hospital incidences of MACEs and all-cause death as well as the lower LVEF.

Acute diagonal-induced ST-elevation myocardial infarction and electrocardiogram-guidance in the era of primary coronary intervention: New insights into an old tool

BACKGROUND

Previous studies, published before the advent of primary reperfusion, described the electrocardiographic features of ST-segment elevation myocardial infarction (STEMI) caused by total diagonal artery occlusion, as demonstrated at pre-discharge coronary angiography. We aimed to assess the electrocardiographic and echocardiographic features in STEMI unequivocally attributed to a diagonal lesion in the era of primary coronary intervention.

METHODS

The electrocardiograms and echocardiograms of patients sustaining STEMI caused by diagonal artery involvement were compared with those of patients with STEMI attributed to proximal or mid left anterior descending artery (LAD) lesions. ST-segment deviations were measured at four different points in each lead and analyzed against TIMI flow and SNuH score. The electrocardiographic and echocardiographic features of each group were mapped.

RESULTS

In contrast to previous studies claiming an ever-present incidence of at least 1-mm ST-segment elevation in leads I and aVL with diagonal STEMI, we report 86% of any ST-elevation in leads I, aVL and V2 (64-71% for ST-elevation >1 mm). Both higher SNuH score and pre-intervention TIMI flow were associated with larger lateral ST-elevations (85.7% and 86.4-95.5%, respectively). Higher prevalence of ST-depression in the inferior leads reflecting reciprocal changes was observed in patients with diagonal-induced STEMI (57-76% vs. 24-51% in LAD obstructions, p <0.05).

CONCLUSION

The most sensitive and predictive sign for acute ischemia was any degree of ST-deviation measured 1 mm beyond the J point. ST-elevations in I, aVL and V₂, sparing V₃-V₅, strongly favor isolated diagonal lesion. Proximal LAD lesion lacking ST-segment elevations in leads I and aVL is primarily due to wraparound LAD anatomy.

Randomized comparison between provisional and routine kissing-balloon technique after main vessel crossover stenting for coronary bifurcation lesions

We compared the myocardial ischemic burden of provisional and routine final kissing-balloon inflation (FKI) with the 1-stent strategy using a second-generation drug-eluting stent for coronary bifurcation lesions (CBL). There are no established guidelines for side branch (SB) intervention after main vessel stenting. In total, 113 CBL patients were randomized to receive different SB intervention strategies: provisional-FKI group (n = 57; FKI only when SB flow was TIMI <3) and routine-FKI group (n = 56; mandatory FKI with aggressive treatment until SB-residual stenosis <50%). Dipyridamole-stress myocardial perfusion scintigraphy with ^99mTc was performed after 8 months. The regional summed-difference score (r-SDS) was calculated according to the coronary territory. The primary endpoint included target vessel ischemia (TVI; r-SDS ≥ 2) at 8 months, whereas the clinical primary endpoint was major adverse cardiovascular events (MACE) at 3 years. The percent (%) myocardial ischemia (100 × SDS/68) was also calculated. At 8 months, TVI was identified in 11 and 4% in the provisional-FKI and routine-FKI groups, respectively (p = 0.226). SB-binary restenosis (48 vs. 4%, p < 0.001) and myocardial ischemia at the SB territory (11 vs. 0%, p = 0.030) were more common in the provisional-FKI group; however, in TVI patients, % myocardial ischemia (4.12 ± 1.23% vs. 3.68 ± 1.04%; p = 0.677) did not significantly differ. Moderate/severe ischemia (>10% myocardial ischemia) was not observed in the target vessel in either group. Long-term cumulative MACE were similar between the groups (9 vs. 14%; p = 0.358). Provisional-FKI according to TIMI-SB flow grade led to similar and acceptable myocardial ischemia, in comparison with routine-FKI, which may contribute to the identical long-term follow-up.