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ORIGINAL ARTICLE
Year : 2015  |  Volume : 18  |  Issue : 3  |  Page : 126-128

Outcome comparison between left circumflex and right coronary artery-related acute inferior wall myocardial infarction


Department of Medicine, Division of Cardiology, University of Dammam, Dammam, Saudi Arabia

Date of Web Publication10-Nov-2015

Correspondence Address:
Mohammed Almansori
Department of Medicine and Interventional Cardiologist, University of Dammam, PO Box 12875, Dammam 31483
Saudi Arabia
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Source of Support: None, Conflict of Interest: None


DOI: 10.4103/1118-8561.169279

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  Abstract 

Background: Left circumflex artery (LCx) related acute ST-segment elevation inferior wall myocardial infarction (IWMI) is less well-reported in literature than the right coronary artery (RCA)-related IWMI. Little is known about the outcome of patients with LCx infarct-related acute IWMI. Recently, studies have shown that LCx-related infarcts carried less favorable outcome. Materials and Methods: Between January 2007 and December 2012, data of all patients with acute IWMI, who presented to a university hospital in Saudi Arabia were reviewed, and the various in-hospital outcomes were compared. Results: A total of 90 patients comprising 63 (70%) patients in the RCA-related IWMI group and 27 (30%) in the LCx-related IWMI group were reviewed. Diabetes mellitus, dyslipidemia and renal impairment were more prevalent in the RCA-related infarct group. The prevalence of atrio-ventricular block (14.3% vs. 0%, P = 0.053) and the frequency of cardiogenic shock needing inotropic support (14.3% vs. 0%, P = 0.053) were higher in the RCA related infarcts. Conclusions: Our study showed that in a sample from Saudi Arabia, the in-hospital prognostic outcomes were less favorable in patients with RCA-related acute IWMI when compared to LCx-related infarcts.

Keywords: Acute myocardial infarction, left circumflex, right coronary artery


How to cite this article:
Almansori M, Ouf S. Outcome comparison between left circumflex and right coronary artery-related acute inferior wall myocardial infarction. Sahel Med J 2015;18:126-8

How to cite this URL:
Almansori M, Ouf S. Outcome comparison between left circumflex and right coronary artery-related acute inferior wall myocardial infarction. Sahel Med J [serial online] 2015 [cited 2024 Mar 28];18:126-8. Available from: https://www.smjonline.org/text.asp?2015/18/3/126/169279


  Introduction Top


The incidence of inferior wall myocardial infarction (IWMI) is comparable to that of anterior wall myocardial infarction (AWMI).[1],[2],[3] Previous studies have reported that, compared with AWMI; IWMI has more favorable short-term and long-term clinical outcomes.[1],[2],[4],[5] However, some distinctive electrocardiographic features, including right ventricular infarction, reciprocal ST-segment depression in precordial leads, or complete heart block, have been reported to contribute adversely to the prognostic outcome in patients with IWMI.[6],[7],[8],[9] Therefore, patients with IWMI do not always have favorable clinical outcomes.[7],[10]

From the anatomical point of view, IWMI is caused by either acute right coronary artery (RCA) or left circumflex artery (LCx) occlusion. Although comparison of the prognostic outcome between anterior and inferior wall myocardial infarction (MI) has been extensively investigated, a similar comparison between IWMI caused by RCA and LCx occlusion is seldom reported.[11],[12]

Little is known about the outcome of patients with LCx-related acute IWMI. It has often been stated that patients with RCA-related IWMI might have a worse outcome because of the higher frequency of rhythm and conduction disturbances.[8],[13],[14] In 2007; Rasoul et al.,[11] evaluated 1683 patients with IWMI and concluded that patients with LCx-related infarcts have higher enzymatic rise and lower ejection fraction. Recently in 2011; Chen and his group [12] studied 646 patients with acute IWMI and showed that LCx-related infarcts carry less favorable 30-day prognostic outcome.


  Materials and Methods Top


A retrospective review of the data of all patients with a diagnosis of acute IWMI who was admitted to King Fahad Hospital of the University, Alkhobar, Saudi Arabia between January 2007 and December 2012. Charts of patients without coronary angiogram or those with significantly missing data were excluded. The sample was divided into RCA-related and LCx-related IWMI groups according to angiographic data. The two groups were compared with regards to various in-hospital outcomes, including the initial and peak levels of cardiac biomarkers, heart failure, heart block, resuscitation, length of hospital stay, and in-hospital mortality. The t-test was used for comparing continuous data and while Chi-square test was used for discrete variables (Fisher's exact test was applied when cell count was small).


  Results Top


A total of 90 patients were reviewed comprising 63 (70%) patients in the RCA-related IWMI group and 27 (30%) patients in the LCx-related IWMI group. [Table 1] shows the baseline characteristics of the groups. The prevalence of diabetes (62% vs. 37%, P = 0.039) (56% vs. 22%, P = 0.005) were significantly higher in the RCA group. The level of serum creatinine of patients in the RCA group was significantly higher (1.3 ± 0.3 vs. 1.0 ± 0.2, P = 0.025). The comparison of different in-hospital outcomes is shown in [Table 2]. Patients in the RCA group developed more heart block (14% vs. 0%, P = 0.053) and had more need for inotropic support (14% vs. 0%, P = 0.053). There were no statistically significant differences in cardiac enzymatic levels, ejection fraction, development of heart failure, need for resuscitation, blood transfusion, length of hospital stay or in-hospital mortality.
Table 1: Baseline clinical characteristics of patients

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Table 2: Outcome differences between RCA and LCx related myocardial infarction

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  Discussion Top


This is, to the best of our knowledge, the first study comparing the acute outcomes between RCA-and LCx-related acute IWMI in a sample from Saudi Arabia. In this series of patients the average hospital stay was about 7-day with an in-hospital mortality of 1.1%. In contrast to the published data,[11],[12] our study showed worse outcomes with RCA-related IWMI compared to LCx related infarcts. This was mainly related to the development of heart block and cardiogenic shock represented by the need for inotropic support. This difference can be attributed to several factors including higher prevalence of diabetes, dyslipidemia and renal impairment noticed in patients with RCA related infarcts. The RCA was dominant in about 65% of cases reflecting a larger infarct area involved by occlusion of this artery. Our study has certain limitations including its retrospective nature, small sample size, lack of information about patients with acute MI due to occlusion of LCx without ST-segment elevation, and the chances that the patients involved in the analysis could have altered the results.[15]


  Conclusion Top


Our study showed that in a sample from Saudi Arabia, the in-hospital outcomes were less favorable in patients with RCA-related acute IWMI when compared to LCx-related infarcts.

 
  References Top

1.
Effectiveness of intravenous thrombolytic treatment in acute myocardial infarction. Gruppo Italiano per lo Studio della Streptochinasi nell'Infarto Miocardico (GISSI). Lancet 1986;1:397-402.  Back to cited text no. 1
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2.
Randomised trial of intravenous streptokinase, oral aspirin, both, or neither among 17,187 cases of suspected acute myocardial infarction: ISIS-2. ISIS-2 (Second International Study of Infarct Survival) Collaborative Group. Lancet 1988;2:349-60.  Back to cited text no. 2
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3.
Yip HK, Chen MC, Chang HW, Hang CL, Hsieh YK, Fang CY, et al. Angiographic morphologic features of infarct-related arteries and timely reperfusion in acute myocardial infarction: Predictors of slow-flow and no-reflow phenomenon. Chest 2002;122:1322-32.  Back to cited text no. 3
    
4.
Stone PH, Raabe DS, Jaffe AS, Gustafson N, Muller JE, Turi ZG, et al. Prognostic significance of location and type of myocardial infarction: Independent adverse outcome associated with anterior location. J Am Coll Cardiol 1988;11:453-63.  Back to cited text no. 4
    
5.
Nienhuis MB, Ottervanger JP, Dambrink JH, de Boer MJ, Hoorntje JC, Gosselink AT, et al. Comparative predictive value of infarct location, peak CK, and ejection fraction after primary PCI for ST elevation myocardial infarction. Coron Artery Dis 2009;20:9-14.  Back to cited text no. 5
    
6.
Hlatky MA, Califf RM, Lee KL, Pryor DB, Wagner GS, Rosati RA. Prognostic significance of precordial ST-segment depression during inferior acute myocardial infarction. Am J Cardiol 1985;55:325-9.  Back to cited text no. 6
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7.
Berger PB, Ryan TJ. Inferior myocardial infarction. High-risk subgroups. Circulation 1990;81:401-11.  Back to cited text no. 7
    
8.
Zehender M, Kasper W, Kauder E, Schönthaler M, Geibel A, Olschewski M, et al. Right ventricular infarction as an independent predictor of prognosis after acute inferior myocardial infarction. N Engl J Med 1993;328:981-8.  Back to cited text no. 8
    
9.
Yip HK, Chen MC, Wu CJ, Chang HW, Yu TH, Yeh KH, et al. Acute myocardial infarction with simultaneous ST-segment elevation in the precordial and inferior leads: Evaluation of anatomic lesions and clinical implications. Chest 2003;123:1170-80.  Back to cited text no. 9
    
10.
Yip HK, Wu CJ, Fu M, Yeh KH, Yu TH, Hung WC, et al. Clinical features and outcome of patients with direct percutaneous coronary intervention for acute myocardial infarction resulting from left circumflex artery occlusion. Chest 2002;122:2068-74.  Back to cited text no. 10
    
11.
Rasoul S, de Boer MJ, Suryapranata H, Hoorntje JC, Gosselink AT, Zijlstra F, et al. Circumflex artery-related acute myocardial infarction: Limited ECG abnormalities but poor outcome. Neth Heart J 2007;15:286-90.  Back to cited text no. 11
    
12.
Chen YL, Hang CL, Fang HY, Tsai TH, Sun CK, Chen CJ, et al. Comparison of prognostic outcome between left circumflex artery-related and right coronary artery-related acute inferior wall myocardial infarction undergoing primary percutaneous coronary intervention. Clin Cardiol 2011;34:249-53.  Back to cited text no. 12
    
13.
Braat SH, de Zwaan C, Brugada P, Coenegracht JM, Wellens HJ. Right ventricular involvement with acute inferior wall myocardial infarction identifies high risk of developing atrioventricular nodal conduction disturbances. Am Heart J 1984;107:1183-7.  Back to cited text no. 13
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14.
Fiol M, Cygankiewicz I, Carrillo A, Bayés-Genis A, Santoyo O, Gómez A, et al. Value of electrocardiographic algorithm based on "ups and downs" of ST in assessment of a culprit artery in evolving inferior wall acute myocardial infarction. Am J Cardiol 2004;94:709-14.  Back to cited text no. 14
    
15.
Abbas AE, Boura JA, Brewington SD, Dixon SR, O'Neill WW, Grines CL. Acute angiographic analysis of non-ST-segment elevation acute myocardial infarction. Am J Cardiol 2004;94:907-9.  Back to cited text no. 15
    



 
 
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