Magnitude and consequences of missing the acute infarct-related circumflex artery

Optical coherence tomography analysis of lesion characteristics and thrombus types in non ST-segment elevation myocardial infarction patients

The precise features of lesions in non-ST-segment elevation myocardial infarction (NSTEMI) patients with total occlusion (TO) of the infarct-related artery (IRA) are still unclear. This study employs optical coherence tomography (OCT) to investigate pathological features in NSTEMI patients with or without IRA TO and explores the relationship between thrombus types and IRA occlusive status. This was a single-center retrospective study. A total of 202 patients diagnosed with NSTEMI were divided into two groups: those with Thrombolysis In Myocardial Infarction (TIMI) flow grade 0 before percutaneous coronary intervention (PCI) (referred to as the TO group, n = 100) and those TIMI flow grade 1-3 (referred to as the Non-TO group, n = 102). Baseline characteristics, coronary angiography findings, and OCT results were collected. Multivariate logistic analysis identified factors influencing TO in NSTEMI. The category of NSTEMI was further subdivided based on the type of electrocardiogram (ECG) into two subgroups: ST segment unoffset myocardial infarction (STUMI) and ST segment depression myocardial infarction (STDMI). This division allows for a more specific classification of NSTEMI cases. The TO group had a younger age, higher male representation, more smokers, lower hypertension and cerebrovascular disease incidence, lower left ventricular ejection fraction (LVEF), and higher creatine kinase myocardial band (CKMB) and creatine kinase (CK) peak levels. In the TO group, LCX served as the main IRA (52.0%), whereas in the Non-TO group, LAD was the predominant IRA (45.1%). Compared to the Non-TO group, OCT findings demonstrated that red thrombus/mixed thrombus was more common in the TO group, along with a lower occurrence of white thrombus (p < 0.001). The TO group exhibited a higher prevalence of STUMI (p = 0.001), whereas STDMI was more commonly observed in the Non-TO group (p = 0.001). NSTEMI presents as STUMI and STDMI distinct entities. Red thrombus/mixed thrombus in IRA often indicates occlusive lesions with STUMI on ECG. White thrombus suggests non-occlusive lesions with STDMI on ECG.

Occlusion of the infarct-related coronary artery presenting as acute coronary syndrome with and without ST-elevation: impact of inflammation and outcomes in a real-world prospective cohort

BACKGROUND

Patients with ST-segment elevation typically feature total coronary occlusion (TCO) of the infarct-related artery (IRA) on angiography, which may result in worse outcomes. Yet, relying solely on electrocardiogram (ECG) findings may be misleading and those presenting with non-ST-segment elevation acute coronary syndromes (NSTE-ACSs) may have TCO as well. Herein, we aimed to delineate clinical characteristics and outcomes of patients with ACS stratified by IRA location.

METHODS

A total of 4787 ACS patients were prospectively recruited between 2009 and 2017 in SPUM-ACS (ClinicalTrials.gov Identifier: NCT01000701). The primary endpoint was major adverse cardiovascular events (MACEs), a composite of all-cause death, non-fatal myocardial infarction and non-fatal stroke at 1 year. Multivariable-adjusted survival models were fitted using backward selection.

RESULTS

A total of 4412 ACS patients were included in this analysis, 56.0% (n = 2469) ST-elevation myocardial infarction (STEMI) and 44.0% (n = 1943) NSTE-ACS. The IRA was the right coronary artery (RCA) in 33.9% (n = 1494), the left-anterior descending coronary artery (LAD) in 45.6% (n = 2013), and the left circumflex (LCx) in 20.5% (n = 905) patients. In STEMI patients, TCO (defined as TIMI 0 flow at angiography) was observed in 55% of cases with LAD, in 63% with RCA, and in 55% with LCx. In those presenting with NSTE-ACS, TCO was more frequent in those with LCx and RCA as compared to the LAD (27 and 24%, respectively, vs. 9%, P < 0.001). Among patients with NSTE-ACS, occlusion of the LCx was associated with an increased risk of MACE during 1 year after the index ACS (fully adjusted hazard ratio 1.68, 95% confidence interval 1.10-2.59, P = 0.02; reference: RCA and LAD). Features of patients with NSTE-ACS associated with TCO of the IRA included elevated lymphocyte and neutrophil counts, higher levels of high-sensitivity C reactive protein (hs-CRP) and high-sensitivity cardiac troponin T, lower eGFR, and notably a negative history of MI.

CONCLUSION

In NSTE-ACS, both LCx and RCA involvement was associated with TCO at angiography despite the absence of ST-segment elevation. Involvement of the LCx, but not the LAD or RCA, as the IRA represented an independent predictor of MACE during 1-year follow-up. Hs-CRP, lymphocyte, and neutrophil counts were independent predictors of total IRA occlusion, suggesting a possible role of systemic inflammation in the detection of TCO irrespective of ECG presentation.

Clinical Significance of Culprit Vessel Occlusion in Patients With Non-ST-Elevation Myocardial Infarction Who Underwent Percutaneous Coronary Intervention

In patients with non-ST-elevation myocardial infarction (NSTEMI), total occlusion of the culprit coronary artery (OCA) is not uncommon. We sought to determine the frequency and clinical impact of OCA at presentation in a large population of patients presenting with NSTEMI and who underwent systematic early invasive management. We performed a post hoc analysis of the TAO (Treatment of Acute Coronary Syndrome with Otamixaban) randomized trial, which included patients with NSTEMI with systematic coronary angiography within 72 hours. We compared the baseline characteristics and outcomes of patients according to whether the culprit vessel was occluded (thrombolysis in myocardial infarction flow grade [TFG] 0 to 1) or patent (TFG 2 to 3) at presentation. A total of 7,473 patients with NSTEMI with only 1 culprit lesion identified were enrolled, of whom 1,702 patients had OCA (22.8%). In the OCA group, coronary angiography was performed earlier (18 ± 15 vs 20 ± 16 hours, p <0.01), the culprit lesion was less likely to be the left anterior descending artery (26.5% vs 41.4%, p <0.001) but with more frequent angiographic thrombus (49.9% vs 22.7%, p <0.01). Culprit artery percutaneous coronary intervention during the index procedure was also more frequent (88.5% vs 78.1%, p <0.001) but with a lower rate of TFG grade 3 after the procedure and higher subsequent peak troponin I levels (8.3 ± 13.6 µg/L vs 5.6 ± 11.9 µg/L, p <0.001). At day 7, patients with OCA had higher mortality, and this persisted after adjustment on gender, Grace risk score, cardiovascular risk factors, and culprit vessel location (0.9% vs 0.4%, p = 0.02; adjusted odds ratio [OR] = 2.55, 95% confidence interval [CI] 1.23 to 5.29, p = 0.01). The absolute difference of mortality was maintained through 30 days: 1.2% versus 0.8%, p = 0.13; OR: 1.72, 95% CI 0.97 to 3.05, but mortality rates were similar by 180 days: 1.5% versus 1.6%, p = 0.8, adjusted OR = 1.11, 95% CI 0.69 to 1.80, p = 0.66. In conclusion, a significant proportion of patients with NSTEMI have a totally occluded culprit vessel at presentation. These patients are at higher risk of early mortality but not at 6 months.

Early ischemic ST-segment and T-wave changes during balloon angioplasty

BACKGROUND

Acute coronary occlusion results in increased T-wave amplitude and ST-segment elevation in the ECG leads facing the ischemic region.

MATERIAL AND METHODS

We performed continuous ECG recording in 34 patients during balloon occlusion of the left anterior descending (LAD), left circumflex (LCx) and right coronary artery (RCA). Delta (Δ) ST and ΔT amplitudes were calculated by subtracting the preinflation values from the values measured during balloon inflation.

RESULTS

Occlusion of the LAD resulted in greater increase in the amplitude of the T wave than of the ST segment in lead V2 (ΔT +3.4 mm, inter-quartile range [IQR] 1-6 mm; ΔST +1.4 mm, 0.5-3 mm). During RCA occlusion, ΔST and ΔT didn't differ significantly. LCx occlusion resulted in significant differences between ΔST and ΔT in all leads, except aVF and V3-V4. In two patients (LCx), we observed a biphasic ST-T response: an initial negative change of the T-wave amplitude was followed by a positive change in leads V1-V2. In leads II, III, aVF and V4-V6, there was an initial positive change, followed by a final negative change towards the end of the occlusion.

CONCLUSION

Continuous 12‑lead ECG recording during balloon occlusion of the LCx resulted in significant differences between the ΔST and ΔT values in all leads except aVF and V3-V4. LAD and RCA occlusion resulted in less evident differences between the ST-segment and T-wave changes. A change in polarity of T-wave changes during balloon occlusion (initial negative and final positive change, or vice versa) proved to be a rare finding.

Totally Occluded Culprit Coronary Artery in Patients with Non-ST-Elevation Myocardial Infarction Undergoing Percutaneous Coronary Intervention

The short- and long-term implications of identifying totally occluded culprit coronary arteries (TOCCA) in patients presenting with non-ST-elevation myocardial infarction (NSTEMI) have not been well studied. This study compares clinical characteristics, short- and long-term outcomes of patients with NSTEMI identified with TOCCA to that of patients with non-TOCCA undergoing percutaneous coronary intervention (PCI). We analyzed data from patients with NSTEMI undergoing single-vessel PCI within the Melbourne Interventional Group multi-center registry between 2005 and 2017. Those with TOCCA were compared to those with non-TOCCA. The primary endpoint was 30-day major adverse cardiac events (MACE). Secondary endpoints included 12-month MACE and long-term mortality. A total of 6,829 patients with NSTEMI had single-vessel PCI of which 954 (14%) had TOCCA. Most TOCCA were non-left anterior descending (right coronary artery 39% versus circumflex 33% versus left anterior descending 26%; p <0.001). Cardiogenic shock and left ventricular dysfunction were higher in the TOCCA group, but non-TOCCA patients had more baseline comorbidities. Thirty-day MACE was higher in the TOCCA group (6.7% versus 3.8%; p <0.001). Long-term mortality with an average follow-up of 4.9 years was higher in the non-TOCCA group (12% versus 18%, p <0.01). Multivariable Cox-proportional hazards regression identified TOCCA as an independent predictor of 30-day MACE (HR = 1.93; 95%CI: 1.4-2.6), but not long-term mortality, which was predicted by baseline comorbidities. In conclusion, while patients with NSTEMI with TOCCA undergoing PCI represent a more unstable subgroup early on, long-term outcomes appear more dependent on baseline comorbidities.

Diagnostic performance of a new ECG algorithm for reducing false positive cases in patients suspected acute coronary syndrome

BACKGROUND

Early and correct diagnosis of ST-segment elevation myocardial infarction (STEMI) is crucial for providing timely reperfusion therapy. Patients with ischemic symptoms presenting with ST-segment elevation on the electrocardiogram (ECG) are preferably transported directly to a catheterization laboratory (Cath-lab) for primary percutaneous coronary intervention (PPCI). However, the ECG often contains confounding factors making the STEMI diagnosis challenging leading to false positive Cath-lab activation. The objective of this study was to test the performance of a standard automated algorithm against an additional high specificity setting developed for reducing the false positive STEMI calls.

METHODS

We included consecutive patients with an available digital prehospital ECG triaged directly to Cath-lab for acute coronary angiography between 2009 and 2012. An adjudicated discharge diagnosis of STEMI or no myocardial infarction (no-MI) was assigned for each patient. The new automatic algorithm contains a feature to reduce false positive STEMI interpretation. The STEMI performance with the standard setting (STD) and the high specificity setting (HiSpec) was tested against the adjudicated discharge diagnosis in a retrospective manner.

RESULTS

In total, 2256 patients with an available digital prehospital ECG (mean age 63 ± 13 years, male gender 71%) were included in the analysis. The discharge diagnosis of STEMI was assigned in 1885 (84%) patients. The STD identified 165 true negative and 1457 true positive (206 false positive and 428 false negative) cases (77.3%, 44.5%, 87.6% and 17.3% for sensitivity, specificity, PPV and NPV, respectively). The HiSpec identified 191 true negative and 1316 true positive (180 false positive and 569 false negative) cases (69.8%, 51.5%, 88.0% and 25.1% for sensitivity, specificity, PPV and NPV, respectively). From STD to HiSpec, false positive cases were reduced by 26 (12,6%), but false negative results were increased by 33%.

CONCLUSIONS

Implementing an automated ECG algorithm with a high specificity setting was able to reduce the number of false positive STEMI cases. However, the predictive values for both positive and negative STEMI identification were moderate in this highly selected STEMI population. Finally, due the reduced sensitivity/increased false negatives, a negative AMI statement should not be solely based on the automated ECG statement.

The CHA2DS2-VASc Risk Score Predicts Total Occlusion in Infarct-Related Arteries in Patients With Non-ST Elevation Myocardial Infarction

Early detection of total coronary artery occlusion (TO) in non-ST elevation myocardial infarction (NSTEMI) patients may be beneficial since invasive treatments are initiated more rapidly in appropriate patients. Previous studies have shown that the CHA2DS2-VASc (congestive heart failure, hypertension, age ≥75 years, diabetes mellitus, previous stroke, vascular disease, age between 65 and 74 years, female gender) score is associated with thrombus burden in acute coronary syndromes. We investigated the association between the CHA2DS2-VASc risk score and TO in patients with NSTEMI who underwent coronary angiography. TIMI (thrombolysis in myocardial infarction) flow 0 was defined as TO and TIMI flow 1-3 was defined as non-total occlusion (non-TO). The NSTEMI patients (n = 400) included were separated into two groups: those with (n = 138) and without (n = 262) TO. We observed that the CHA2DS2-VASc score was higher in the TO group (3.86 ± 2.32 vs 2.15 ± 1.79, P <.001). The Global Registry of Acute Coronary Events (GRACE) score (P = .002) and the CHA2DS2-VASc score (P < .001) were also found to be significant independent predictors for total occlusion in multiple regression analysis. A CHA2DS2-VASc score ≥3 had 68.1% sensitivity and 64.0% specificity (area under the curve (AUC): 0.657, 95% CI: 0.585-0.725, P < .001) for predicting TO. The CHA2DS2-VASc score was an effective tool that predicted TO in patients with NSTEMI.

Impact of acute total occlusion of the culprit artery on outcome in NSTEMI based on the results of a large national registry

BACKGROUND

The impact of acute total occlusion (TO) of the culprit artery in non-ST-segment elevation myocardial infarction (NSTEMI) is not fully established. We aimed to evaluate the clinical and angiographic phenotype and outcome of NSTEMI patients with TO (NSTEMI_TO) compared to NSTEMI patients without TO (NSTEMI_NTO) and those with ST-segment elevation and TO (STEMI_TO).

METHODS

Demographic, clinical and procedure-related data of patients with acute myocardial infarction who underwent percutaneous coronary intervention (PCI) between 2014 and 2017 from the Polish National Registry were analysed.

RESULTS

We evaluated 131,729 patients: NSTEMI_NTO (n = 65,206), NSTEMI_TO (n = 16,209) and STEMI_TO (n = 50,314). The NSTEMI_TO group had intermediate results compared to the NSTEMI_NTO and STEMI_TO groups regarding mean age (68.78 ± 11.39 vs 65.98 ± 11.61 vs 64.86 ± 12.04 (years), p < 0.0001), Killip class IV on admission (1.69 vs 2.48 vs 5.03 (%), p < 0.0001), cardiac arrest before admission (2.19 vs 3.09 vs 6.02 (%), p < 0.0001) and death during PCI (0.43 vs 0.97 vs 1.76 (%), p < 0.0001)-for NSTEMI_NTO, NSTEMI_TO and STEMI_TO, respectively. However, we noticed that the NSTEMI_TO group had the longest time from pain to first medical contact (median 4.0 vs 5.0 vs 2.0 (hours), p < 0.0001) and the lowest frequency of TIMI flow grade 3 after PCI (88.61 vs 83.36 vs 95.57 (%), p < 0.0001) and that the left circumflex artery (LCx) was most often the culprit lesion (14.09 vs 35.86 vs 25.42 (%), p < 0.0001).

CONCLUSIONS

The NSTEMI_TO group clearly differed from the NSTEMI_NTO group. NSTEMI_TO appears to be an intermediate condition between NSTEMI_NTO and STEMI_TO, although NSTEMI_TO patients have the longest time delay to and the worst result of PCI, which can be explained by the location of the culprit lesion in the LCx.

Total coronary occlusion in non ST elevation myocardial infarction: Time to change our practice?

Based on 12‑lead electrocardiogram (ECG) findings, myocardial infarction (MI) patients are dichotomized to ST-elevation MI (STEMI) and non ST-elevation MI (NSTEMI) in terms of management strategy. NSTEMI patients are increasing in numbers worldwide, among which an approximately 30% are associated with a total occlusion of a coronary artery. This review summarizes recent evidence in epidemiology, clinical, laboratory, ECG and prognostic characteristics of this NSTEMI sub-group. Patients with a diagnosis of NSTEMI and a total occluded coronary artery (TOCA) represent a sub-group of NSTEMI patients with total occlusion of coronary arteries and associated high-risk that are frequently not managed according to a STEMI-like pathway. The present review echoes a call for action in changing our everyday clinical practice. Therefore, we propose a new triage algorithm by which recognition of high-risk features in NSTEMI patients is central in order to identify STEMI 'equivalents' among NSTEMI patients in terms of similar pathology and high-risk who may benefit from immediate invasive strategy (<2 h).

ECG analysis in patients with acute coronary syndrome undergoing invasive management: rationale and design of the electrocardiography sub-study of the MATRIX trial

BACKGROUND

The twelve‑lead electrocardiogram (ECG) has become an essential tool for the diagnosis, risk stratification, and management of patients with acute coronary syndromes (ACS). However, several areas of residual controversies or gaps in evidence exist. Among them, P-wave abnormalities identifying atrial ischemia/infarction are largely neglected in clinical practice, and their diagnostic and prognostic implications remain elusive; the value of ECG to identify the culprit lesion has been investigated, but validated criteria indicating the presence of coronary occlusion in patients without ST-elevation are lacking; finally, which criteria among the multiple proposed, better define pathological Q-waves or success of revascularisation deserve further investigations.

METHODS

The Minimizing Adverse hemorrhagic events via TRansradial access site and systemic Implementation of AngioX (MATRIX) trial was designed to test the impact of bleeding avoidance strategies on ischemic and bleeding outcomes across the whole spectrum of patients with ACS receiving invasive management. The ECG-MATRIX is a pre-specified sub-study of the MATRIX programme which aims at analyzing the clinical value of ECG metrics in 4516 ACS patients (with and without ST-segment elevation in 2212 and 2304 cases, respectively) with matched pre and post-treatment ECGs.

CONCLUSIONS

This study represents a unique opportunity to further investigate the role of ECGs in the diagnosis and risk stratification of ACS patients with or without ST-segment deviation, as well as to assess whether the radial approach and bivalirudin may affect post-treatment ECG metrics and patterns in a large contemporary ACS population.

Door-to-balloon time and cardiac mortality in acute myocardial infarction by total occlusion of the left circumflex artery

BACKGROUND

Acute myocardial infarction (AMI) caused by total occlusion of the left circumflex artery (LCX) can present as non-ST-segment elevation myocardial infarction (NSTEMI). We evaluate whether door-to-balloon time (DBT) is associated with cardiac mortality in patients with total occlusion of the LCX.

PATIENTS AND METHODS

From the Korea Acute Myocardial Infarction Registry, patients with AMI who had total occlusion with a Thrombolysis In Myocardial Infarction flow grade of 0 were included. We determined the factors for delay in primary percutaneous coronary intervention (DBT>90 min) and evaluated cardiac mortality for a median period of 14 months.

RESULTS

Mean DBT was 68 min (interquartile range=50-156 min), and the achievement rate of DBT less than or equal to 90 min was 66.9% in the entire study population. More than half of patients with total occlusion of LCX were presented as NSTEMI (57.7%). Among patients with total occlusion of the LCX, the mean DBT was 136 min (interquartile range=60-484 min), and the achievement rate of DBT less than or equal to 90 min was 42.8%. On multivariate analysis, LCX occlusion was an important factor for DBT more than 90 min (odds ratio: 1.766, P<0.001). Among patients with LCX occlusion, cardiac mortality was higher in patients with ST-segment elevation (6.2 vs. 11.0%, P=0.024).

CONCLUSION

This study showed that LCX occlusion was a significant factor for the delay in primary percutaneous coronary intervention on account of presenting as NSTEMI. Cardiac mortality was not associated with DBT more than 90 min but with ST-segment elevation in AMI patients with total occlusion of the LCX.

Predictors of mortality in patients with non-anterior ST-segment elevation myocardial infarction: Analysis from the HORIZONS-AMI trial

OBJECTIVES

We sought to identify clinical, electrocardiographic (ECG), and angiographic characteristics that are predictive of 3-year mortality after primary percutaneous coronary intervention (PCI) in patients with non-anterior ST-elevation myocardial infarction (NA-STEMI) from the Harmonizing Outcomes With Revascularization and Stents in Acute Myocardial Infarction (HORIZONS-AMI) trial.

BACKGROUND

Which patients with NA-STEMI undergoing PCI have a poor prognosis is uncertain.

METHODS

NA-STEMI was defined as ST-segment elevation in lateral (V5, V6, I, aVL), inferior (II, III, aVF), or inferolateral (I, II, III, aVF, and V5-V6) ECG leads or posterior myocardial infarction with ST-segment depression of ≥1 mm in ≥2 contiguous anterior leads. Cox regression was used to identify independent predictors of 3-year mortality. Missing data were imputed using multiple imputation.

RESULTS

In HORIZONS-AMI, 2,578/3,602 patients had no prior coronary artery bypass grafting, underwent single-vessel PCI, and had baseline ECG data assessed in an independent core laboratory. Among them, 1,495 (58.0%) had NA-STEMI. Patients with NA-STEMI had lower 3-year mortality risk than those with anterior STEMI (4.5% versus 7.1%, P = 0.004). The independent predictors of increased 3-year mortality in NA-STEMI were older age (median > 59.0 years), diabetes, reduced LVEF (≤50%), Killip class ≥2, post-procedure TIMI flow 0-2 versus 3, renal insufficiency, and ST-resolution <30% at 60 min post-PCI. Patients with 0, 1, 2, 3, and ≥4 of these risk factors had 3-year mortality rates of 1.8%, 2.3%, 3.1%, 6.1%, and 36.3%, respectively (P < 0.0001).

CONCLUSIONS

Although NA-STEMI carries a better prognosis than anterior STEMI, high-risk patient cohorts with NA-STEMI may be identified who have substantial 3-year mortality.

High-sensitivity cardiac troponin T as a predictor of acute Total occlusion in patients with non-ST-segment elevation acute coronary syndrome

Background

A large percentage of patients with non‐ST‐segment acute coronary syndrome (NSTE‐ACS) present with acute total occlusion (TO) of some major epicardial vessel that does not generate electrocardiographic changes. Ongoing research into the methods of accurately predicting acute TO have not yielded great success.

Hypothesis

High‐sensitivity cardiac troponin T (hs‐cTnT) has a good predictive value for the presence of acute TO of the culprit artery in patients with NSTE‐ACS.

Methods

A single‐center retrospective study of 1011 patients diagnosed with NSTE‐ACS who underwent coronary angiography and hs‐cTnT measured on admission. The predictive value of hs‐cTnT in the presence of acute TO was assessed by the area under the ROC curve.

Results

The mean age of the population was 67.12 ± 13.18 and 74.1% were male. 7.3% of the patients presented with acute TO. The AUC for hs‐cTnT to predict acute TO was 0.95. A hs‐cTnT value of 1006 ng/L (71.8 fold of the URL) best predicted the presence of acute TO, with a sensitivity of 86% and specificity of 95% positive predictive value (PPV): 86% and negative predictive value (NPV): 94%.

Conclusions

Hs‐cTnT was a good predictor of acute TO in patients with NSTE‐ACS. Hs‐cTnT values greater than 1006 ng/L were highly predictive of acute TO of a major coronary vessel.

Comparison of Outcomes and Intervention Among Patients With Non-ST-Segment Elevation Acute Myocardial Infarction of Those With a Left Circumflex Versus Those With a Non-Left Circumflex-Related Coronary Artery (From the ELISA-3 Trial)

Previous studies found that patients with an acute coronary syndrome (ACS) due to occlusion of the left circumflex (LC) coronary artery often present without ST-elevation, leading to a delay in diagnosis and revascularization, a larger infarct size, and a worse prognosis. In this subgroup analysis of the ELISA-3 study (early or late intervention in high-risk non-ST-segment elevation acute coronary syndromes [NSTE-ACS]) incidence, characteristics and prognosis of LC-related NSTE-ACS was investigated, and the outcome of early versus late invasive strategy was compared. In 383 of 542 patients the culprit vessel could be identified, with the LC artery in 112 (29%) of them. Patients with LC-related ACS had more often single vessel disease and underwent percutaneous coronary intervention more and CABG less frequently. The primary end point of the combined incidences of death, myocardial infarction, and recurrent ischemia at 30-day follow-up occurred in 9.0% of LC versus 16.5% of non-LC-related ACS (p = 0.057). Enzymatic infarct size and incidence of bleeding were comparable. Of patients with LC-related ACS, 62 were assigned to an early and 50 to a late invasive treatment with a median time from admission to angiography of 5.5 and 65.7 hours, respectively. The primary end point occurred in 9.7% and 8.0%, respectively (p = 1.00) with comparable enzymatic infarct size and bleeding. In conclusion, no significant differences in outcome were found between patients with an LC- and a non-LC-related NSTE-ACS. In LC-related NSTE-ACS, angiography within 12 hours of admission is feasible but not superior to angiography after more than 48 hours.

Clinical and Prognostic Value of the Electrocardiogram in Patients With Acute Occlusion of the Left Circumflex Coronary Artery

The utility of the electrocardiogram (ECG) in patients with acute left circumflex (LC) coronary occlusion is not established. This study aimed at determining the clinical, angiographic, and prognostic characteristics associated with the different patterns of ST-segment changes in patients with LC occlusion. A cohort of 314 patients with LC occlusion was categorized according to the admission ECG: (1) ST-segment elevation (ST-E, n=208), (2) isolated ST-segment depression in precordial leads (ST-D, n=62), and (3) negligible ST-segment changes (No-ST, n=44). Clinical variables, coronary angiography, and 30-day major adverse cardiac event (MACE) (in-hospital ventricular fibrillation, 1-month mortality, or heart failure) were compared among the three groups. As compared with No-ST, patients with ST-E or ST-D presented more advanced Killip class, higher troponin peak, lower LV ejection fraction, and were independently associated with MACE (odds ratio 5.43, 95% confidence interval 1.09 to 27.20 and odds ratio 3.39, 95% confidence interval 0.66 to 17.50, respectively). Patients with ST-D were tardily reperfused, had more often mitral regurgitation (23.1% vs 9.3% in ST-E and 3.3% in No-ST, p=0.03), and presented ST-segment elevation in leads V7 to V9 in 12 of 16 cases with available recordings. Culprit proximal LC predominated in ST-D (41.9%), distal LC in ST-E (42.8%), and obtuse marginal in No-ST (59.1%) (all p<0.01). The No-ST had smaller coronary vessels and more collaterals. In conclusion, the three ST-segment patterns of LC occlusion identify patients with different clinical, angiographic, and prognostic characteristics. Patients with ST-depression pattern require a prompt reperfusion therapy and could be better recognized by recording leads V7 to V9.

Acute myocardial infarction and lesion location in the left circumflex artery: importance of coronary artery dominance

AIMS

Due to the limitations of 12-lead ECG, occlusions of the left circumflex artery (LCX) are more likely to present as non-ST-elevation acute coronary syndrome (NSTEACS) compared with other coronary arteries. We aimed to study mortality in patients with LCX lesions and to assess the importance of coronary artery dominance on triage of these patients.

METHODS AND RESULTS

From the Eastern Danish Heart Registry, 3,632 NSTEACS and 3,907 ST-elevation myocardial infarction (STEMI) consecutive, single-vessel disease patients were included. LCX was the culprit in 25% of NSTEACS and 14% of STEMIs (p<0.001). LCX lesions presented predominantly as STEMI in left dominant coronary arteries compared with NSTEACS (46% vs. 30%, p<0.001). Higher 30-day mortality was found in LCX-STEMI compared with LCX-NSTEACS (HR 7.9, 95% CI: 3.2-19.7, p<0.001) with no difference in long-term mortality (HR 0.9, 95% CI: 0.7-1.2, p=0.5). LCX-NSTEACS were not associated with higher mortality compared with other NSTEACS lesions.

CONCLUSIONS

The 12-lead ECG seems sufficient for triage of patients with LCX lesions as a majority of patients with a large LCX due to a dominant left coronary artery present as STEMI. Patients with LCX-NSTEACS do not have higher mortality compared with patients with LCX-STEMI or NSTEACS with lesions in other coronary territories.

Inter-lead correlation analysis for automated detection of cable reversals in 12/16-lead ECG

BACKGROUND AND OBJECTIVE

A crucial factor for proper electrocardiogram (ECG) interpretation is the correct electrode placement in standard 12-lead ECG and extended 16-lead ECG for accurate diagnosis of acute myocardial infarctions. In the context of optimal patient care, we present and evaluate a new method for automated detection of reversals in peripheral and precordial (standard, right and posterior) leads, based on simple rules with inter-lead correlation dependencies.

METHODS

The algorithm for analysis of cable reversals relies on scoring of inter-lead correlations estimated over 4s snapshots with time-coherent data from multiple ECG leads. Peripheral cable reversals are detected by assessment of nine correlation coefficients, comparing V6 to limb leads: (I, II, III, -I, -II, -III, -aVR, -aVL, -aVF). Precordial lead reversals are detected by analysis of the ECG pattern cross-correlation progression within lead sets (V1-V6), (V4R, V3R, V3, V4), and (V4, V5, V6, V8, V9). Disturbed progression identifies the swapped leads.

RESULTS

A test-set, including 2239 ECGs from three independent sources-public 12-lead (PTB, CSE) and proprietary 16-lead (Basel University Hospital) databases-is used for algorithm validation, reporting specificity (Sp) and sensitivity (Se) as true negative and true positive detection of simulated lead swaps. Reversals of limb leads are detected with Se = 95.5-96.9% and 100% when right leg is involved in the reversal. Among all 15 possible pairwise reversals in standard precordial leads, adjacent lead reversals are detected with Se = 93.8% (V5-V6), 95.6% (V2-V3), 95.9% (V3-V4), 97.1% (V1-V2), and 97.8% (V4-V5), increasing to 97.8-99.8% for reversals of anatomically more distant electrodes. The pairwise reversals in the four extra precordial leads are detected with Se = 74.7% (right-sided V4R-V3R), 91.4% (posterior V8-V9), 93.7% (V4R-V9), and 97.7% (V4R-V8, V3R-V9, V3R-V8). Higher true negative rate is achieved with Sp > 99% (standard 12-lead ECG), 81.9% (V4R-V3R), 91.4% (V8-V9), and 100% (V4R-V9, V4R-V8, V3R-V9, V3R-V8), which is reasonable considering the low prevalence of lead swaps in clinical environment.

CONCLUSIONS

Inter-lead correlation analysis is able to provide robust detection of cable reversals in standard 12-lead ECG, effectively extended to 16-lead ECG applications that have not previously been addressed.

Electrocardiographic findings during balloon angioplasty of the left circumflex coronary artery - influence of location of the ischemic segments with respect to the obtuse margin of the left ventricle

BACKGROUND

Acute left circumflex coronary artery (LCx) occlusion is not easily detected by the standard 12-lead electrocardiogram (ECG).

METHODS

In 16 patients continuous ECG recording was performed during balloon occlusion. The treated lesions were divided into proximal and distal based on the location of the ischemic segments with respect to the left obtuse margin of the heart.

RESULTS

Mean ΔST (=ST amplitude during inflation - pre-inflation ST) ≥0.5mm in both leads I and aVL predicted a proximal occlusion site with sensitivity of 62.5% (95% confidence interval [CI] 24.9-91.5%), specificity 100% (95% CI 63.1-100%), positive predictive value 100% (95% CI 47.8-100%), and negative predictive value 72.7% (95% CI 39-94%). In lead III, mean ΔST was +0.3mm in the distal and -0.2mm in the proximal group, respectively (p=0.036).

CONCLUSIONS

ST elevation in leads I and aVL is associated with myocardial ischemia at or proximal to the left obtuse margin.

Frequency, clinical and angiographic characteristics, and outcomes of high-risk non-ST-segment elevation acute coronary syndromes patients with left circumflex culprit lesions

BACKGROUND

The relationship between culprit vessel, infarct size, and outcomes in non-ST-segment elevation acute coronary syndromes (NSTE ACS) is unclear. In some reports, the left circumflex artery (LCX) was more often the culprit at angiography than the right coronary artery (RCA) or left anterior descending artery (LAD), and infarcts were larger with LCX culprits.

METHODS

We determined culprit vessel frequency and initial patency (TIMI flow grade), median fold elevation of peak troponin above the upper limit of normal, and outcomes (30-day death or myocardial infarction [MI] and 1-year mortality) by culprit vessel in high-risk NSTE ACS patients in the EARLY ACS trial.

RESULTS

Of 9406 patients, 2066 (22.0%) had angiographic core laboratory data. We evaluated 1774 patients for whom the culprit artery was not the left main, a bypass graft, or branch vessel. The culprit was the LCX in 560 (31.6%), LAD in 653 (36.8%), and RCA in 561 (31.6%) patients. There were fewer women (24.1%) and more prior MI (25.5%) among patients with a culprit LCX compared with those with a culprit LAD or RCA. Patients with LCX (21.2%) and RCA (27.5%) culprits more often had an occluded artery (TIMI 0/1) than did those with LAD (11.3%). Peak troponin elevation was significantly higher for LCX than RCA or LAD culprits. LCX culprit vessels were not associated with worse 30-day or 1-year outcomes in adjusted models.

CONCLUSIONS

Among patients with NSTE ACS, the frequencies of LCX, LAD, and RCA culprits were similar. Although LCX lesions were associated with higher peak troponin levels, there was no difference in short- or intermediate-term outcomes by culprit artery.

Location of the culprit coronary lesion and its association with delay in door-to-balloon time (from a multicenter registry of primary percutaneous coronary intervention)

Current guidelines recommend shorter door-to-balloon times (DBTs) (<90 minutes) for patients with ST-elevation myocardial infarction (STEMI). Clinical factors, including patient or hospital characteristics, associated with prolonged DBT have been identified, but angiographic variables such as culprit lesion location have not been thoroughly investigated. We aimed to evaluate the effect of culprit artery location on DBT of patients with STEMI who underwent percutaneous coronary intervention (PCI). Data were analyzed from 1,725 patients with STEMI who underwent PCI from August 2008 to March 2014 at 16 Japanese hospitals. Patients were divided into 3 groups according to culprit artery location, right coronary artery (RCA), left anterior descending artery (LAD), and left circumflex artery (LC), and associations with DBT were assessed. The LC group had a trend toward a longer DBT among the 3 groups (97.1 [RCA] vs 98.1 [LAD] vs 105.1 [LC] minutes; p = 0.058). In-hospital mortality was also significantly higher in patients with a left coronary artery lesion (3.5% [RCA] vs 6.3% [LAD] vs 5.4% [LC]; p = 0.041). In-hospital mortality for patients with DBT >90 minutes was significantly higher compared with patients with DBT ≤90 minutes (6.5% vs 3.6%; p = 0.006). Multivariate logistic regression analysis revealed that the LC location was an independent predictor for DBT >90 minutes (odds ratio, 1.45; 95% confidence interval, 1.04 to 2.01; p = 0.028). In conclusion, LC location was an independent predictor of longer DBT. The difficulties in diagnosing LC-related STEMI need further evaluation.

Incidence and impact of totally occluded culprit coronary arteries in patients presenting with non-ST-segment elevation myocardial infarction

The accuracy of the 12-lead electrocardiogram in detecting coronary artery occlusion is limited. We sought to determine the incidence, distribution, and outcomes of patients who have total occlusion of the culprit artery but present with non-ST-segment elevation myocardial infarction (NSTEMI). The randomized Acute Catheterization and Urgent Intervention Triage Strategy trial enrolled 13,819 patients presenting with non-ST-segment elevation acute coronary syndromes who underwent an early invasive strategy. The present study includes 1,319 patients with baseline biomarker elevation (NSTEMI) and no history of coronary artery bypass graft who underwent percutaneous coronary intervention of a single culprit vessel. We compared the baseline characteristics and outcomes according to whether the culprit vessel was occluded (baseline Thrombolysis In Myocardial Infarction [TIMI] 0 to 1) or patent (TIMI 2 to 3 flow) by angiographic core laboratory assessment. TIMI 0 to 1 flow in the culprit artery was present in 262 of 1,319 (19.9%) patients. The incidence of coronary occlusion was 28.4%, 19.3%, and 12.6% in patients with NSTEMI because of right coronary, left circumflex, and left anterior descending artery disease, respectively. Patients with an occluded culprit artery were more commonly men and had ST-segment deviation ≥1 mm. One-year outcomes, including death (3.5% vs 3.0%, p = 0.68) and myocardial infarction (8.4% vs 9.6%, p = 0.47), did not differ significantly between patients with versus without occluded culprit arteries, respectively. In conclusion, the present study demonstrates that the culprit artery is totally occluded in approximately 1 in 5 patients presenting with NSTEMI and single-vessel disease; however, the presence of total occlusion in NSTEMI was not associated with an incremental hazard of death or reinfarction at 1 year.

Intracoronary electrocardiogram ST-segment elevation in patients with non-ST-segment elevation myocardial infarction and its association with culprit lesion location and myocardial injury

AIMS

An intracoronary electrocardiogram (IC-ECG) is a sensitive method to detect local myocardial ischaemia. We investigated the prevalence of IC-ECG ST-segment elevation (STE) with respect to culprit lesion location in patients with non-ST-segment elevation myocardial infarction (NSTEMI) and its relationship with elevated levels of cardiac biomarkers.

METHODS AND RESULTS

We examined 87 NSTEMI patients who underwent IC-ECG recording by locating the insulated polymer-coated guidewire distal to the culprit lesion before percutaneous coronary intervention (PCI). Cardiac biomarkers were serially examined. IC-ECG STE was observed in 24 patients (27.6%) before PCI, and was significantly more frequent in patients with LCx culprit lesions (LAD vs. LCx vs. RCA, 12.1% vs. 53.3% vs. 16.7%; p<0.001). Peak cardiac troponin I (cTnI) values were associated with IC-ECG STE, ejection fraction (EF), cTnI values on admission, and type B2/C lesions. In multivariate analysis, IC-ECG STE (odds ratio [OR], 5.04; 95% confidence intervals [CI]: 1.51-16.85; p=0.009), and EF (OR, 0.95; 95% CI: 0.90-1.00; p=0.043) were predictors of greater peak cTnI values.

CONCLUSIONS

IC-ECG STE was not uncommon in NSTEMI patients, particularly those with LCx culprit lesions. IC-ECG monitoring before PCI may help identify NSTEMI patients with high risk of greater myocardial injury.

Infarct artery distribution and clinical outcomes in occluded artery trial subjects presenting with non-ST-segment elevation myocardial infarction (from the long-term follow-up of Occluded Artery Trial [OAT])

We hypothesized that the insensitivity of the electrocardiogram in identifying acute circumflex occlusion would result in differences in the distribution of the infarct-related artery (IRA) between patients with non-ST-segment elevation myocardial infarction (NSTEMI) and STEMI enrolled in the Occluded Artery Trial. We also sought to evaluate the effect of percutaneous coronary intervention to the IRA on the clinical outcomes for patients with NSTEMI. Overall, those with NSTEMI constituted 13% (n = 283) of the trial population. The circumflex IRA was overrepresented in the NSTEMI group compared to the STEMI group (42.5 vs 11.2%; p <0.0001). The 7-year clinical outcomes for the patients with NSTEMI randomized to percutaneous coronary intervention and optimal medical therapy versus optimal medical therapy alone were similar for the primary composite of death, myocardial infarction, and class IV congestive heart failure (22.3% vs 20.2%, hazard ratio 1.20, 99% confidence interval 0.60 to 2.40; p = 0.51) and the individual end points of death (13.8% vs 17.0%, hazard ratio 0.82, 99% confidence interval 0.37 to 1.84; p = 0.53), myocardial infarction (6.1 vs 5.1%, hazard ratio 1.11, 99% confidence interval 0.28 to 4.41; p = 0.84), and class IV congestive heart failure (6.7% vs 6.0%, hazard ratio 1.50, 99% confidence interval 0.37 to 6.02; p = 0.45). No interaction was seen between the electrocardiographically determined myocardial infarction type and treatment effect (p = NS). In conclusion, the occluded circumflex IRA is overrepresented in the NSTEMI population. Consistent with the overall trial results, stable patients with NSTEMI and a totally occluded IRA did not benefit from randomization to percutaneous coronary intervention.

Left circumflex occlusion in acute myocardial infarction (from the National Cardiovascular Data Registry)

Compared to occlusions of other major coronary arteries, patients presenting with acute left circumflex (LCx) occlusion usually have ST-segment elevation on the electrocardiogram <50% of the time, potentially delaying treatment and resulting in worse outcomes. In contemporary practice, little is known about the clinical outcomes of patients with LCx territory occlusion without ST-segment elevation myocardial infarction (STEMI). We identified patients with myocardial infarction from April 2004 to June 2009 in the CathPCI Registry treated with percutaneous coronary intervention for culprit LCx territory occlusion, excluding those with previous coronary artery bypass grafting. Logistic generalized estimating equation modeling was used to compare the outcomes, including in-hospital mortality between patients with STEMI and non-STEMI (NSTEMI) adjusting for differences in the baseline characteristics. Of the 27,711 patients with myocardial infarction and acute LCx territory occlusion, 18,548 (67%) presented with STEMI and 9,163 (33%) with NSTEMI. With the exception of a greater proportion of cardiac risk factors and cardiac history in the NSTEMI group, the demographic and baseline characteristics were clinically similar between the 2 groups, despite the statistical significance resulting from the large population. The patients with STEMI were more likely to have a proximal LCx culprit lesion (63% vs 27%, p <0.0001) and had greater risk-adjusted in-hospital mortality (odds ratio 1.36, 95% confidence interval 1.12 to 1.65, p = 0.002) compared to patients with NSTEMI. In conclusion, acute LCx territory occlusion often presents as NSTEMI, but patients with NSTEMI and occlusion have a lower mortality risk than those with STEMI, possibly because of factors such as the amount of myocardium involved, the lesion location along the vessel, and/or a dual blood supply.

Comparison of prognostic outcome between left circumflex artery-related and right coronary artery-related acute inferior wall myocardial infarction undergoing primary percutaneous coronary intervention

BACKGROUND

This study evaluated the 30-day clinical outcome of patients with acute inferior wall ST-elevation myocardial infarction (AIW-STEMI) from occlusion of the left circumflex artery (LCX) vs the right coronary artery (RCA) undergoing primary percutaneous coronary intervention (PCI).

HYPOTHESIS

The clinical outcomes of AIW-STEMI caused by RCA and LCX occlusion may be different for patients undergoing primary PCI.

METHODS

Between May 2002 and September 2009, 646 consecutive patients with AIW-STEMI undergoing primary PCI were enrolled. Of these patients, 520 (80.5%) with AIW-STEMI caused by RCA occlusion were categorized into group 1, whereas the remaining 126 (19.5%) whose AIW-STEMI was caused by LCX occlusion served as group 2.

RESULTS

The results demonstrated that the frequency of advanced congestive heart failure, respiratory failure requiring mechanical ventilatory support, and 30-day mortality were remarkably higher in group 2 than in group 1 (all P < 0.01). Conversely, the incidence of right ventricular infarction and complete heart block were notably higher in group 1 than in group 2 (all P < 0.001). Additionally, the peak level of creatine kinase-isoenzyme MB was significantly higher, whereas the left ventricular ejection fraction was notably lower in group 2 than in group 1. Multivariate analysis demonstrated that advanced CHF, high serum creatinine level, low systolic blood pressure, low left ventricular ejection fraction, and LCX as the infarct-related artery were significantly and independently predictive of 30-day mortality (all P < 0.05).

CONCLUSIONS

The 30-day prognostic outcome was less favorable in LCX-related AIW-STEMI compared with RCA-related AIW-STEMI undergoing primary PCI.

Acute myocardial infarction due to left circumflex artery occlusion and significance of ST-segment elevation

Acute occlusion of the left circumflex (LC) artery can be difficult to diagnose. The aim of the present study was to assess the incidence of LC occlusion in patients with acute myocardial infarction (AMI) requiring percutaneous coronary intervention (PCI), the frequency of ST-segment versus non-ST-segment elevation presentation among them, and to correlate the electrocardiographic findings with the outcomes. The clinical characteristics and outcomes of consecutive patients from November 2001 through December 2007 with AMI within 7 days before PCI of a single acutely occluded culprit vessel were included in the present analysis. Of the 1,500 patients, the culprit lesion was located in the right coronary artery, left anterior descending artery, or LC artery in 44.7%, 35.8%, and 19.5% of patients, respectively. Of the 1,500 patients, 72% presented with ST-segment elevation AMI, but only 43% were patients with a LC lesion (n = 127). PCI was significantly less likely (80%, 83%, and 70% for right coronary, left anterior descending, and LC artery, respectively; p < 0.001) to be performed within 24 hours for LC occlusions than for occlusions in the other territories. Among those with a non-ST-segment elevation AMI, the highest post-PCI troponin levels were in patients with a LC artery occlusion (median 1.4, 1.3, and 2.5 ng/ml; p < 0.001). No significant difference was found in the in-hospital mortality (4.4%, 7.4%, and 6.5%; p = 0.66) or major adverse cardiovascular event (9.2%, 13.9%, and 11.6%; p = 0.53) rates for right, left anterior descending, and LC occlusions, respectively. In conclusion, our results have demonstrated that in clinical practice, the LC artery is the least frequent culprit vessel among patients treated invasively for AMI. Patients with LC occlusion are less likely to present with ST-segment elevation AMI and have emergency PCI. The study results suggest that detection of these patients has been suboptimal, highlighting the need to improve the diagnostic approach toward the detection of an acutely occluded LC artery.