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ORIGINAL ARTICLE
Year : 2015  |  Volume : 28  |  Issue : 2  |  Page : 597-601

Angiographic and clinical outcomes among patients with acute coronary syndromes presenting with isolated anterior ST-segment depression


1 Department of Cardiology, Benha Faculty of Medicine, Benha University, Benha, Kalubia, Egypt
2 Department of Cardiology, Shebin Elkom Teaching Hospital, Shebin Elkom, Menoufia, Egypt

Date of Submission25-May-2014
Date of Acceptance10-Nov-2014
Date of Web Publication31-Aug-2015

Correspondence Address:
Mohamed Salem
Department of Cardiology, Benha Faculty of Medicine, Benha University, Benha 13511
Egypt
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/1110-2098.163925

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  Abstract 

Objectives
To evaluate both angiographic and clinical outcomes in patients with acute coronary syndrome (ACS) presenting with isolated anterior ST-segment depression on 12-lead ECG.
Background
ACS is an umbrella term used to cover a spectrum of events caused by acute myocardial ischemia.
Patients and methods
The study included 50 consecutive patients with ACS. All patients had isolated ST depression in the anterior leads on admission ECG. Coronary angiography and assessment of cardiac biomarkers were performed at baseline. According to TIMI flow grade in the culprit artery and the result of cardiac markers, patients were subdivided into three groups: group I: TIMI flow grade 0/1 and positive markers, group II: thrombolysis in myocardial infarction (TIMI) flow grade 2/3 and positive markers, and group III: TIMI flow grade 2/3 and negative markers. In-hospital and 30-day outcome were reported.
Results
On the basis of coronary angiography findings and results of cardiac markers, 12 patients (24%) had totally occluded culprit artery plus positive markers (group I) and 10 patients (20%) had TIMI flow II/III plus subtotal occlusion in the culprit artery and positive markers (group II), whereas 28 patients (56%) patients had TIMI flow II/III and negative markers (group III). In-hospital and 30-day outcomes did not differ between groups.
Conclusion
Among patients with ACS presenting with isolated anterior ST-segment depression, about one-quarter had an occluded culprit artery and elevated cardiac markers.

Keywords: acute coronary syndrome, cardiac biomarkers, coronary angiography


How to cite this article:
Salem M, Hassan A, Elftoh AA, Kabil H, Abou-Elainen H. Angiographic and clinical outcomes among patients with acute coronary syndromes presenting with isolated anterior ST-segment depression. Menoufia Med J 2015;28:597-601

How to cite this URL:
Salem M, Hassan A, Elftoh AA, Kabil H, Abou-Elainen H. Angiographic and clinical outcomes among patients with acute coronary syndromes presenting with isolated anterior ST-segment depression. Menoufia Med J [serial online] 2015 [cited 2020 Feb 26];28:597-601. Available from: http://www.mmj.eg.net/text.asp?2015/28/2/597/163925


  Introduction Top


The presence of ST-segment elevation, especially when accompanied by reciprocal changes in a patient with typical symptoms, is highly predictive of evolving AMI [1]. Not all patients who develop myocardial necrosis have an abnormal ECG; thus, a normal ECG does not rule out myocardial infarction (MI) because the new sensitive biomarkers can detect very small quantities of myocardial necrosis in a range where ECG abnormalities may not be observed [2] . Common ECG findings in UA/non st-segment elevation myocardial infarction (NSTEMI) include ST-segment depression, transient ST-segment elevation, and T-wave inversion. However, ~20% of patients with NSTEMI confirmed by cardiac marker have no ischemic ECG changes. The limited sensitivity and specificity of 12-lead ECG in diagnosing st-segment elevation myocardial infarction (STEMI) is exemplified by the clinical scenario of isolated anterior ST-segment depression [2] . This ECG finding can represent pathophysiology across the spectrum of acute coronary syndrome (ACS):

  1. Plaque rupture with a patent artery and no elevation of cardiac biomarkers leading to unstable angina;
  2. A patent artery supplying the anterior myocardium with elevated cardiac biomarkers (NSTEMI); or
  3. Acute thrombotic occlusion of the posterior circulation with elevated cardiac biomarkers (posterior STEMI).
Previous studies have shown that acute thrombotic occlusion of a vessel supplying the posterior wall is particularly challenging to diagnose, both because of its inconsistent presentation on the ECG and the relatively small contribution of the posterior wall toward the QRS complex in the traditional anterior precordial leads [3] . In this study, we aimed to evaluate both angiographic and clinical outcomes in patients with ACS presenting with isolated anterior ST-segment depression on 12-lead ECG.


  Patients and methods Top


Study design

This single-arm longitudinal study included 50 consecutive patients with ACS who were admitted to the coronary care unit (CCU) during the period from November 2011 to June 2012. All patients had isolated ST-segment depression in anterior leads on admission ECG. We aimed to evaluate both angiographic and clinical outcomes in this category of patients. Key inclusion criteria were patients with ACS with ECG evidence of at least 1 mm ST-segment depression in leads V 1 -V 4 at least and patients with chest pain of at least 10 min duration. Key exclusion criteria were patients with ST-segment depression or elevation in other leads, and patients with hemodynamic or electrical instability, chronic renal or hepatic failure, malignancy.

Baseline evaluation

Baseline evaluation included a review of medical history, clinical examination, laboratory investigation, and 12-lead ECG. Review of medical history included demographic data (age, sex), risk factors for coronary artery disease (diabetes mellitus, hypertension, smoking, dyslipidemia, family history of ischemic heart disease), medical history (previous MI, unstable angina, heart failure, arrhythmia), previous coronary intervention, and cardiac medications. Cardiac markers including CK, CK-MB, and cardiac troponins were analyzed on admission and 6 h later

Study medications

All patients received the standard anti-ischemic (β-blockers, nitrates) and antithrombotic measures (low-molecular-weight heparin, aspirin, and loading plus maintenance dose of clopidogrel).

Coronary angiography

All patients underwent coronary angiography, which was carried out according to the standard technique of cardiac catheterization and angiography. The culprit artery was detected and TIMI Flow was graded in each patient.

TIMI 0: Complete occlusion with no distal run-off.

TIMI I: Some penetration of the contrast agent beyond the point of obstruction, but with poor distal run-off.

TIMI II: Perfusion of the entire vessel with good but delayed distal run-off.

TIMI III: Full perfusion of the entire vessel with normal distal run-off.

Study protocol

According to TIMI flow grade in the culprit artery and the results of cardiac markers, patients were subdivided into three groups:

Group I: TIMI flow grade 0/1 and positive markers,

Group II: TIMI flow grade 2/3 and positive markers, and

Group III: TIMI flow grade 2/3 and negative markers.

Study follow-up

  1. In-hospital outcome included mortality, reinfarction, recurrent chest pain, arrhythmias, and heart failure.
  2. Thirty-day outcomes including all-cause mortality, reinfarction, heart failure and re ischemia, and need for target vessel revascularization.
Statistical analysis

The data collected were tabulated and analyzed using SPSS version 11 ( SPSS Inc, Chicago, IL, USA). Quantitative data were expressed as mean ± SD. The one-way analysis of variance test was used for between-group analysis. Qualitative data were expressed as number and percentage and analyzed using the χ2 -test. P less than 0.05 was considered to indicate statistical significance.


  Results Top


Study population

The mean age of the patients was 50 ± 5.7 years (48 ± 4.8, 51 ± 6.1, 50 ± 2.2, in group I, II, III respectively, P = 0.51). Sixty-two percent of the patients were men, 62% had diabetes mellitus, 52% were smokers, 36% had hypertension, 62% had dyslipidemia, and 30% had a family history of coronary artery disease. Two percent had previous MI, 38% had previous angina, and 4% had undergone a previous coronary intervention. Between-group analysis did not show a significant difference [Table 1].
Table 1 Baseline characteristics

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Clinical presentation on admission

Chest pain was the most common symptom (78%) on admission, dyspnea was reported in 12%, and pulmonary edema in 10%. Between-group analysis did not show significant differences.

Electrocardiogram on admission

All patients had ST-segment depression in the anterior leads, 40% of patients had 1 mm ST-segment depression (41, 40, and 39% in groups I, II, and III, respectively, P = 0.9), whereas 60% had more than 1 mm ST-segment depression (58, 60, and 61% in groups I, II, and III, respectively, P = 0.9). Forty-two percent of all patients had ST depression from V 1 -V 4 (41, 50, and 39% in groups I, II, and III, respectively, P = 0.4) whereas 58% had ST depression extending from V 1 -V 6 (58, 50, and 61% in groups I, II, and III, respectively, P = 0.5) [Table 2].
Table 2 Electrocardiogram on admission

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Clinical findings on admission

The mean heart rate was 79 ± 12 bpm, the mean systolic blood pressure was 130 ± 22 mmHg, and the mean diastolic blood pressure was 81 ± 14 mmHg, and 18% of the patients had third heart sound, 16% had bilateral basal crepitations, and 18% had systolic murmur. There was no significant difference between groups.

Cardiac biomarkers

Cardiac troponin T was positive in 22 patients (44%), with a mean value 0.59 ± 0.76 μg/l. The mean cardiac troponin was 1.2 ± 0.84 and 0.12±0.09 μg/l in groups I and II, respectively (P = 0.001). The mean CK-MB was 45.0 ± -5.54 U/l. Between-group analysis showed that CK-MB was 50 ± 10, 40 ± 0.00 U/l in groups I and II, respectively (P = 0.42).

Angiographic findings

The mean time between admission to CCU and coronary angiography was 72 ± 12 h, ranging from 12 h to 1 week. The mean total TIMI flow was 2.5 ± 0.43. The culprit artery was occluded in 12 (24%) patients with TIMI flow 0/1. TIMI flow grade II/III was reported in 10 patients (20%) in whom subtotal occlusion in the culprit artery was detected. However, 28 patients (56%) had TIMI flow grade II/III without evidence of significant coronary stenosis or thrombosis. None of the patients with occluded culprit artery had negative cardiac markers. On the basis of coronary angiography finding and the results of cardiac markers, 12 patients (24%) had totally occluded culprit artery plus positive markers (group I), 10 patients (20%) had TIMI flow II/III with subtotal occlusion in the culprit artery and positive markers (group II), whereas 28 patients (56%) patients had TIMI flow II/III and negative markers (group III). In group I, LCX, LAD, and RCA were the culprit artery in 42, 33, and 25% of patients, respectively. In group II, LCX, LAD, and RCA were the culprit artery in 20, 60, and 20% of patients, respectively. There was no significant correlation between the degree of ST-segment depression on ECG and TIMI flow grade on coronary angiography [Figure 1].
Figure 1: Combined angiographic and biomarker fi ndings

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In-hospital outcome

Recurrent chest pain was reported in seven (14%) patients, ventricular arrhythmias in six (12%) patients, and heart failure developed in five (10%) patients. In group I, chest pain was reported in three (25%) patients, ventricular arrhythmias in three (25%) patients, and heart failure in two (17%) patients. In group II, chest pain developed in two (20%) patients, arrhythmias in one (10%) patient, and heart failure in (10%) patients. In group III, chest pain developed in two (7.1%) patients, arrhythmias in two (7.1%) patients, and heart failure in two (7%) patients. Between-group analysis did not show significant differences in the above-mentioned adverse events.

Thirty-day outcome

There was no mortality during the entire study period. Reinfarction (NSTEMI) was reported in one patient from group II. Heart failure was reported in four patients (two patients from group I, one patient from group II, and one patient from group III). Between-group analysis did not show significant differences in the above-mentioned adverse events.


  Discussion Top


Among ACS patients with anterior ST-segment depression in this study, about one-quarter had an occluded culprit artery and elevated cardiac biomarkers. However, this was not associated with worse short-term clinical outcome compared with patients with patent culprit artery. In this study, the mean time from admission to CCU and coronary angiography was 72 h. It is possible that a significant improvement in clinical outcome would be observed if the presence of an occluded artery had been diagnosed at the time of presentation and an emergent intervention had been carried out. The current American College of Cardiology/American Heart Association guidelines recommend a door-to-balloon time of less than 90 min for STEMI patients undergoing primary previous coronary intervention. Multiple studies have shown that treatment delays result in greater morbidity and mortality [4]. This was in agreement with Pride et al. [5] , who reported that among patients with ACS and isolated ST-segment depression in the anterior leads, 26% had an occluded culprit artery (TIMI flow grade 0/1) and elevated cardiac troponins. In addition, our findings corroborate findings from an analysis of non-STEMI patients enrolled in the PARAGON-B (Platelet IIb/IIIa Antagonism for the Reduction of Acute Coronary Syndrome Events in a Global Organization Network) trial, in which 27% of patients had an occluded culprit artery at the time of coronary angiography [6] . That such patients were more likely to have culprit lesions in the posterior circulation is not surprising as the difficulty in diagnosing MI involving the posterior circulation is well documented [5] . Boden et al. [7] reported that 46% of patients initially classified as having anterior non-Q-wave MIs were later found to have posterior STEMI as evidenced by evolution of ECG changes and cardiac biomarkers.

In this study, LCX, LAD, and RCA were the culprit artery in 42, 33, and 25% of patients who had an occluded culprit artery, respectively. Pride et al. [5] , in their study, showed that the culprit artery was most often the left circumflex artery (48%) in this category of patients with ACS and isolated ST-segment depression in the anterior leads. De Winter et al. [8] reported that when the left circumflex artery is occluded, MI may affect an electrocardiographically silent area of the heart, and the traditional 12-lead ECG may be entirely normal. However, LAD was the culprit artery in about one-third of our patients with occluded culprit artery. Evidence from the literature suggests that 2% of patients with proximal left anterior descending coronary artery occlusion may present with anterior ST-segment depression [8] .

The mean value of cardiac troponin was higher (1.2 ± 0.84 ug/l) in patients with an occluded culprit artery compared with those with patent artery (0.12 ± 0.09 ug/l). This may indicate larger infarction size in patients with occluded culprit artery. Pride et al. [5] , reported that peak serum CK-MB concentrations were 3.3 times the upper limit of normal among patients with an occluded culprit artery and 1.5 times the upper limit of normal among patients with a patent artery irrespective of biomarker positivity. When stratified by culprit artery, the difference in the enzymatic estimate of infarct size was significantly higher among patients with an occluded artery irrespective of the artery involved. In our study, we did not report significant differences between groups either in hospital or in 30-day outcomes. This was not in agreement with the results of Pride et al. [5] , who reported that the 30-day incidence of the composite of death and MI was significantly higher among patients with an occluded artery (8.6%) than among those with a patent culprit artery and either elevated cardiac troponins (6.3%) or not (2.9%) (P = 0.006). Moreover, in the study of de Winter et al. [8] , the incidence of MI was significantly higher among patients with an occluded artery than those with patent artery with either elevated or nonelevated cardiac markers (9, 6, 3%), respectively. This discrepancy in results may be attributed to the small sample size in our study (50 patients) when compared with 1198 patients in the study carried out by Pride et al. [5] .


  Conclusion Top


Among patients with ACS presenting with isolated anterior ST-segment depression, about one-quarter of patients had an occluded culprit artery and elevated cardiac markers.

Recommendations

  1. It is reasonable to perform emergency coronary angiography and a percutaneous coronary intervention when available in patients with ACS presenting with isolated ST-segment depression in anterior leads.
  2. A larger sample size is recommended in further studies for better assessment of clinical outcome.


Study limitation

  1. Small sample size.
  2. Short follow-up period.

  Acknowledgements Top


Conflicts of interest

There are no conflicts of interest.

 
  References Top

1.
Alpert JS, Thygesen K, Antman E, Bassand JP Myocardial infarction redefined - a consensus document of The Joint European Society of Cardiology/American College of Cardiology Committee for the redefinition of myocardial infarction. J Am Coll Cardiol 2000; 36 :959-969.  Back to cited text no. 1
    
2.
Somers MP, Brady WJ, Perron AD, Mattu A The prominent T wave: electrocardiographic differential diagnosis. Am J Emerg Med 2002; 20 :243-251.  Back to cited text no. 2
    
3.
McClelland AJ, Owens CG, Menown IB, Lown M, Adgey AA Comparison of the 80-lead body surface map to physician and to 12-lead electrocardiogram in detection of acute myocardial infarction. Am J Cardiol 2003; 92 :252-257.  Back to cited text no. 3
    
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Antman EM, Anbe DT, Armstrong PW, Bates ER, Green LA, Hand Met al. ACC/AHA guidelines for the management of patients with ST-elevation myocardial infarction; A report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Committee to Revise the 1999 Guidelines for the Management of patients with acute myocardial infarction). J Am Coll Cardiol 2004; 44 :E1-E211.  Back to cited text no. 4
    
5.
Pride YB, Tung P, Mohanavelu S, Zorkun C, Wiviott SD, Antman EM, et al.TIMI Study Group Angiographic and clinical outcomes among patients with acute coronary syndromes presenting with isolated anterior ST-segment depression: a TRITON-TIMI 38 (Trial to Assess Improvement in Therapeutic Outcomes by Optimizing Platelet Inhibition With Prasugrel-Thrombolysis In Myocardial Infarction 38) substudy. JACC Cardiovasc Interv 2010; 3 :806-811.  Back to cited text no. 5
    
6.
Wang TY, Zhang M, Fu Y, Armstrong PW, Newby LK, Gibson CM, et al. Incidence, distribution, and prognostic impact of occluded culprit arteries among patients with non-ST-elevation acute coronary syndromes undergoing diagnostic angiography. Am Heart J 2009; 157 :716-723.  Back to cited text no. 6
    
7.
Boden WE, Kleiger RE, Gibson RS, Schwartz DJ, Schechtman KB, Capone RJ, Roberts R Electrocardiographic evolution of posterior acute myocardial infarction: importance of early precordial ST-segment depression. Am J Cardiol 1987; 59 :782-787.  Back to cited text no. 7
    
8.
De Winter RJ, Verouden NJ, Wellens HJ, Wilde AAInterventional Cardiology Group of the Academic Medical Center A new ECG sign of proximal LAD occlusion. N Engl J Med 2008; 35:2071-2073.  Back to cited text no. 8
    


    Figures

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    Tables

  [Table 1], [Table 2]



 

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