Acta Cardiol Sin 2015;31:226-231 Original Article
doi: 10.6515/ACS20150105A
Acute Coronary Syndrome
Left Ventricular Dyssynchrony Predicts Left Main Coronary Artery Disease in Patients with Non-ST-Segment Elevation Myocardial Infarction Yueh-Juh Lin,1 Kuo-Liong Chien,2,3 Hsuan-Kuang Chen,1 Chia-Sung Wang1 and Ching-Chi Chu1
Background: The purpose of our study was to examine whether left ventricular dyssynchrony predicts left main coronary artery stenosis in patients with non-ST-segment elevation myocardial infarction. Methods: A total of 100 consecutive patients with non-ST-segment elevation myocardial infarction underwent echocardiography and coronary artery angiography. The 3-dimensional echocardiography-derived left ventricular dyssynchrony parameter was determined by using the standard deviation of the time to the minimal systolic volume for the 16 segments. A stenosis ³ 50% of the diameter of the left main coronary artery or a stenosis ³ 70% in 1 or more of the major epicardial vessels or their main branches was considered significant. Results: The logistic regression analysis revealed that this parameter (odds ratio 1.2; 95% confidence interval, 1.01-1.42; p = 0.04) was the independent predictor of left main coronary artery stenosis. The receiver operating characteristic curve analysis revealed 8.86 as the optimal cutoff value to predict left main coronary artery stenosis (sensitivity, 71.4%; specificity, 89.2%). Conclusions: The assessment of left ventricular dyssynchrony by 3-dimensional echocardiography is useful for a noninvasive diagnosis of the left main coronary artery stenosis in patients with non-ST-segment elevation myocardial infarction.
Key Words:
Dyssynchrony · Left main coronary artery stenosis · Non-ST-segment elevation myocardial infarction
associated with left ventricular dyssynchrony.2 Timely identification is more important for left main coronary artery stenosis (LMCAS) than for other coronary stenotic lesions in patients with non-ST-segment elevation myocardial infarction (NSTEMI). Unprotected left main coronary disease in acute coronary syndrome is associated with high mortality.3 However, the accuracy of the diagnosis of LMCAS usually depends on invasive coronary angiography. Thus far, only a few studies focusing on noninvasive diagnostic techniques for LMCAS have been conducted. Lead aVR ST segment elevation in 12-lead electrocardiograms has been suggested to be a marker of left main coronary artery disease.4 However, such electrocardiographic criterion has not yet been well verified in patients with NSTEMI. Therefore, a noninvasive diagnostic tool for LMCAS should be developed for clinical practice.
INTRODUCTION Left ventricular mechanical dyssynchrony can occur in patients with coronary artery disease who had no prior myocardial infarction and narrow QRS complexes.1 Significant coronary artery stenotic lesions have been
Received: September 16, 2014 Accepted: January 5, 2015 1 Department of Cardiology, En Chu Kong Hospital; 2Institute of Epidemiology and Preventive Medicine, National Taiwan University; 3 Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan. Address correspondence and reprint requests to: Dr. Ching-Chi Chu, Department of Cardiology, En Chu Kong Hospital, No. 399, Fuxing Rd., Sanxia District, New Taipei City 23702, Taiwan. Tel: 886-2-26723456 ext. 6651; Fax: 886-2-2674-6863; E-mail: ccchu00014@yahoo. com.tw
Acta Cardiol Sin 2015;31:226-231
226
Dyssynchrony and Left Main Disease
The purpose of our study was to examine the possible relationship between left ventricular dyssynchrony and LMCAS in patients with NSTEMI. In addition, we also aimed to verify the lead aVR ST segment elevation-related electrocardiographic criteria for the diagnosis of LMCAS in the same study population.
rough V4), inferior (lead II, III, or aVF), and lateral (lead I, aVL, V5, or V6) ST-segment depressions ³ 0.5 mm; the number of leads with ST-segment depression ³ 0.5 mm; and the presence of T-wave inversion.4
Echocardiography and left ventricular dyssynchrony parameters Two-dimensional echocardiography was performed using the IE33 ultrasound system (Philips Ultrasound, Bothell, WA, USA) and an S5-1 probe (1-5 MHz). The left ventricular dimension and wall thickness were measured,6 and the left ventricular mass index was calculated.7-10 The regional wall motion of the left ventricle was assessed by wall motion score index.11 Three-dimensional echocardiographic images were obtained by the IE33 ultrasound system (Philips Ultrasound) equipped with an X3-1 matrix array transducer, the results of which were sent to a workstation for offline analysis. The standard deviation of the time to the minimal systolic volume for the 16 segments (Tmsv16SD), expressed as a percent cardiac cycle, was calculated as a left ventricular dyssynchrony parameter. Left ventricular ejection fraction was also calculated. All work was done automatically with commercially available software (3DQ ADV; QLAB, Version 8.1, Philips Ultrasound). To assess the reproducibility of Tmsv-16SD and left ventricular ejection fraction, 25 subjects were randomly selected for reliability analyses. The intraclass correlation coefficient was 0.889 for Tmsv-16SD and 0.825 for left ventricular ejection fraction.
MATERIALS AND METHODS Study population A total of 165 consecutive patients with suspected unstable angina or NSTEMI diagnosed at En Chu Kong Hospital, a regional hospital in Taiwan, between January 1, 2010, and December 31, 2011, were enrolled in the study. The study was approved by the local institution review board (ECKIRB98018), and informed consent was obtained before the study was initiated. The inclusion criteria were as follows: 1) patients who presented at the hospital with symptoms of ischemic chest pain at rest, lasting for 10 minutes or longer, within the previous 24 hours; 2) a transient ST-segment elevation > 0.5 mm, transient or persistent ST-segment depression > 0.5 mm, or T-wave inversion > 1 mm within 12 hours before or after chest pain was noted; 3) serum troponin-I concentrations were determined and followed-up within 12 hours; 4) sinus cardiac rhythm; 5) and coronary artery angiography indicated by clinical judgment. The exclusion criteria included a persistent ST-segment elevation > 1 mm, pregnancy, a permanent pacemaker implant, and poor echocardiographic image quality. All patients sequentially underwent successful 2-dimensional echocardiography, 3-dimensional echocardiography, and coronary artery angiography. The time intervals between echocardiographic studies and coronary artery angiographic exams were less than 2 hours. Among them, 100 patients had elevated troponin-I level. The patients with elevated troponin-I levels were diagnosed with NSTEMI and their data were selected for current analysis.
Coronary artery angiography A stenosis ³ 50% of the diameter of the left main coronary artery or a stenosis ³ 70% of the diameter of 1 or more of the major epicardial vessels or their main branches was considered significant. Thereafter, the grade of the thrombolysis in the myocardial infarction flow was determined.12 Statistical analysis Logistic regression analysis was performed to determine the diagnostic potential of left ventricular dyssynchrony as an indicator of LMCAS. The following variables were considered as possible predictors: age, sex, diabetes mellitus, hypertension, smoking, hypercholes-
Electrocardiographic criteria The following electrocardiographic criteria were examined on the admission electrocardiogram: ST-segment elevation ³ 0.5 mm in lead aVR and ST-segment elevation ³ 1.0 mm in lead aVR; 5 anterior (lead V1 th227
Acta Cardiol Sin 2015;31:226-231
Yueh-Juh Lin et al.
RESULTS
terolemia, family history of coronary artery disease, history of myocardial infarction, previous percutaneous coronary intervention, blood pressure, heart rate, Killip class ³ 2,13 peak troponin-I level, electrocardiographic parameters, thrombolysis in myocardial infarction risk score,14 left ventricular mass index, left ventricular wall motion score index, left ventricular ejection fraction, and Tmsv-16SD. The receiver operating characteristic curve analysis was used to determine the optimal cutoff Tmsv-16SD value to predict LMCAS. A p value of 75% stenosis of left main and/or 3-vessel disease with > 90% stenosis in > 2 proximal lesions of the left anterior descending coronary artery and other major epicardial arteries), Kosuge et al.19 demonstrated that an ST-segment elevation ³ 1.0 mm in lead aVR on an admission electrocardiogram is highly suggestive of severe left Acta Cardiol Sin 2015;31:226-231
CONCLUSIONS The 3-dimensional echocardiographic assessment of left ventricular dyssynchrony has the potential to improve the accuracy of noninvasive diagnosis for LMCAS in patients with NSTEMI.
ACKNOWLEDGEMENTS The authors thank Miss Shu-Hua Chen for her en230
Dyssynchrony and Left Main Disease
thusiastic support. The authors also acknowledge statistical assistance provided by the National Translational Medicine and Clinical Trial Resource Center [which is founded by the National Research Program for Biopharmaceuticals (NRPB) at the National Science Council of Taiwan; NSC101-2325-B-002-078] and the Department of Medical Research in the National Taiwan University Hospital.
10.
REFERENCES
11.
1. Lee PW, Zhang Q, Yip GW, et al. Left ventricular systolic and diastolic dyssynchrony in coronary artery disease with preserved ejection fraction. Clin Sci 2009;116:521-9. 2. Ng AC, Tran da T, Allman C, et al. Prognostic implications of left ventricular dyssynchrony early after non-ST elevation myocardial infarction without congestive heart failure. Eur Heart J 2010; 31:298-308. 3. Montal.escot G, Brieger D, Eagle KA, et al. Unprotected left main revascularization in patients with acute coronary syndromes. Eur Heart J 2009;30:2308-17. 4. Nikus K, Järvinen O, Sclarovsky S, et al. Electrocardiographic presentation of left main disease in patients undergoing urgent or emergent coronary artery bypass grafting. Postgrad Med 2011; 123:42-8. 5. Barrabés JA, Figueras J, Moure C, et al. Prognostic value of lead aVR in patients with a first non-ST-segment elevation acute myocardial infarction. Circulation 2003;108:814-9. 6. Sahn DJ, DeMaria A, Kisslo J, Weyman A. Recommendations regarding quantitation in M-mode echocardiography: results of a survey of echocardiographic measurements. Circulation 1978; 58:1072-83. 7. Devereux RB, Reichek N. Echocardiographic determination of left ventricular mass in man. Anatomic validation of the method. Circulation 1977;55:613-8. 8. de Simone G, Daniels SR, Devereux RB, et al. Left ventricular mass and body size in normotensive children and adults: assessment of allometric relations and impact of overweight. J Am Coll Cardiol 1992;20:1251-60. 9. Rosen BD, Fernandes VR, Nasir K, et al. Age, increased left ventricular mass, and lower regional myocardial perfusion are re-
12. 13.
14.
15.
16.
17. 18.
19.
231
lated to greater extent of myocardial dyssynchrony in asymptomatic individuals: the multi-ethnic study of atherosclerosis. Circulation 2009;120:859-66. Lang RM, Bierig M, Devereux RB, et al. Chamber Quantification Writing Group; American Society of Echocardiography’s Guidelines and Standards Committee; European Association of Echocardiography. Recommendations for chamber quantification: a report from the American Society of Echocardiography’s Guidelines and Standards Committee and the Chamber Quantification Writing Group, developed in conjunction with the European Association of Echocardiography, a branch of the European Society of Cardiology. J Am Soc Echocardiogr 2005;18:1440-63. Eek C, Grenne B, Brunvand H, et al. Strain echocardiography and wall motion score index predicts final infarct size in patients with non-ST-segment-elevation myocardial infarction. Circ Cardiovasc Imaging 2010;3:187-94. The TIMI Study Group. The Thrombolysis in Myocardial Infarction (TIMI) trial: phase I findings. N Engl J Med 1985;312:932-6. DeGeare VS, Boura JA, Grines LL, et al. Predictive value of the Killip classification in patients undergoing primary percutaneous coronary intervention for acute myocardial infarction. Am J Cardiol 2001;87:1035-8. Antman EM, Cohen M, Bernink PJ, et al. The TIMI risk score for unstable angina/non-ST elevation MI: a method for prognostication and therapeutic decision making. JAMA 2000;284:835-42. Takaro T, Hultgren HN, Lipton MJ, Detre KM. The VA cooperative randomized study of surgery for coronary arterial occlusive disease II. Subgroup with significant left main lesions. Circulation 1976;54:III 107-17. Chaitman BR, Fisher LD, Bourassa MG, et al. Effect of coronary bypass surgery on survival patterns in subsets of patients with left main coronary artery disease. Report of the Collaborative Study in Coronary Artery Surgery (CASS). Am J Cardiol 1981; 48:765-77. Teirstein PS, Price MJ. Left main percutaneous coronary intervention. J Am Coll Cardiol 2012;60:1605-13. Yamaji H, Iwasaki K, Kusachi S, et al. Prediction of acute left main coronary artery obstruction by 12-lead electrocardiography. ST segment elevation in lead aVR with less ST segment elevation in lead V(1). J Am Coll Cardiol 2001;38:1348-54. Kosuge M, Ebina T, Hibi K, et al. An early and simple predictor of severe left main and/or three-vessel disease in patients with non-ST-segment elevation acute coronary syndrome. Am J Cardiol 2011;107:495-500.
Acta Cardiol Sin 2015;31:226-231
doi: 10.6515/ACS20150105A
Acute Coronary Syndrome
Left Ventricular Dyssynchrony Predicts Left Main Coronary Artery Disease in Patients with Non-ST-Segment Elevation Myocardial Infarction Yueh-Juh Lin,1 Kuo-Liong Chien,2,3 Hsuan-Kuang Chen,1 Chia-Sung Wang1 and Ching-Chi Chu1
Background: The purpose of our study was to examine whether left ventricular dyssynchrony predicts left main coronary artery stenosis in patients with non-ST-segment elevation myocardial infarction. Methods: A total of 100 consecutive patients with non-ST-segment elevation myocardial infarction underwent echocardiography and coronary artery angiography. The 3-dimensional echocardiography-derived left ventricular dyssynchrony parameter was determined by using the standard deviation of the time to the minimal systolic volume for the 16 segments. A stenosis ³ 50% of the diameter of the left main coronary artery or a stenosis ³ 70% in 1 or more of the major epicardial vessels or their main branches was considered significant. Results: The logistic regression analysis revealed that this parameter (odds ratio 1.2; 95% confidence interval, 1.01-1.42; p = 0.04) was the independent predictor of left main coronary artery stenosis. The receiver operating characteristic curve analysis revealed 8.86 as the optimal cutoff value to predict left main coronary artery stenosis (sensitivity, 71.4%; specificity, 89.2%). Conclusions: The assessment of left ventricular dyssynchrony by 3-dimensional echocardiography is useful for a noninvasive diagnosis of the left main coronary artery stenosis in patients with non-ST-segment elevation myocardial infarction.
Key Words:
Dyssynchrony · Left main coronary artery stenosis · Non-ST-segment elevation myocardial infarction
associated with left ventricular dyssynchrony.2 Timely identification is more important for left main coronary artery stenosis (LMCAS) than for other coronary stenotic lesions in patients with non-ST-segment elevation myocardial infarction (NSTEMI). Unprotected left main coronary disease in acute coronary syndrome is associated with high mortality.3 However, the accuracy of the diagnosis of LMCAS usually depends on invasive coronary angiography. Thus far, only a few studies focusing on noninvasive diagnostic techniques for LMCAS have been conducted. Lead aVR ST segment elevation in 12-lead electrocardiograms has been suggested to be a marker of left main coronary artery disease.4 However, such electrocardiographic criterion has not yet been well verified in patients with NSTEMI. Therefore, a noninvasive diagnostic tool for LMCAS should be developed for clinical practice.
INTRODUCTION Left ventricular mechanical dyssynchrony can occur in patients with coronary artery disease who had no prior myocardial infarction and narrow QRS complexes.1 Significant coronary artery stenotic lesions have been
Received: September 16, 2014 Accepted: January 5, 2015 1 Department of Cardiology, En Chu Kong Hospital; 2Institute of Epidemiology and Preventive Medicine, National Taiwan University; 3 Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan. Address correspondence and reprint requests to: Dr. Ching-Chi Chu, Department of Cardiology, En Chu Kong Hospital, No. 399, Fuxing Rd., Sanxia District, New Taipei City 23702, Taiwan. Tel: 886-2-26723456 ext. 6651; Fax: 886-2-2674-6863; E-mail: ccchu00014@yahoo. com.tw
Acta Cardiol Sin 2015;31:226-231
226
Dyssynchrony and Left Main Disease
The purpose of our study was to examine the possible relationship between left ventricular dyssynchrony and LMCAS in patients with NSTEMI. In addition, we also aimed to verify the lead aVR ST segment elevation-related electrocardiographic criteria for the diagnosis of LMCAS in the same study population.
rough V4), inferior (lead II, III, or aVF), and lateral (lead I, aVL, V5, or V6) ST-segment depressions ³ 0.5 mm; the number of leads with ST-segment depression ³ 0.5 mm; and the presence of T-wave inversion.4
Echocardiography and left ventricular dyssynchrony parameters Two-dimensional echocardiography was performed using the IE33 ultrasound system (Philips Ultrasound, Bothell, WA, USA) and an S5-1 probe (1-5 MHz). The left ventricular dimension and wall thickness were measured,6 and the left ventricular mass index was calculated.7-10 The regional wall motion of the left ventricle was assessed by wall motion score index.11 Three-dimensional echocardiographic images were obtained by the IE33 ultrasound system (Philips Ultrasound) equipped with an X3-1 matrix array transducer, the results of which were sent to a workstation for offline analysis. The standard deviation of the time to the minimal systolic volume for the 16 segments (Tmsv16SD), expressed as a percent cardiac cycle, was calculated as a left ventricular dyssynchrony parameter. Left ventricular ejection fraction was also calculated. All work was done automatically with commercially available software (3DQ ADV; QLAB, Version 8.1, Philips Ultrasound). To assess the reproducibility of Tmsv-16SD and left ventricular ejection fraction, 25 subjects were randomly selected for reliability analyses. The intraclass correlation coefficient was 0.889 for Tmsv-16SD and 0.825 for left ventricular ejection fraction.
MATERIALS AND METHODS Study population A total of 165 consecutive patients with suspected unstable angina or NSTEMI diagnosed at En Chu Kong Hospital, a regional hospital in Taiwan, between January 1, 2010, and December 31, 2011, were enrolled in the study. The study was approved by the local institution review board (ECKIRB98018), and informed consent was obtained before the study was initiated. The inclusion criteria were as follows: 1) patients who presented at the hospital with symptoms of ischemic chest pain at rest, lasting for 10 minutes or longer, within the previous 24 hours; 2) a transient ST-segment elevation > 0.5 mm, transient or persistent ST-segment depression > 0.5 mm, or T-wave inversion > 1 mm within 12 hours before or after chest pain was noted; 3) serum troponin-I concentrations were determined and followed-up within 12 hours; 4) sinus cardiac rhythm; 5) and coronary artery angiography indicated by clinical judgment. The exclusion criteria included a persistent ST-segment elevation > 1 mm, pregnancy, a permanent pacemaker implant, and poor echocardiographic image quality. All patients sequentially underwent successful 2-dimensional echocardiography, 3-dimensional echocardiography, and coronary artery angiography. The time intervals between echocardiographic studies and coronary artery angiographic exams were less than 2 hours. Among them, 100 patients had elevated troponin-I level. The patients with elevated troponin-I levels were diagnosed with NSTEMI and their data were selected for current analysis.
Coronary artery angiography A stenosis ³ 50% of the diameter of the left main coronary artery or a stenosis ³ 70% of the diameter of 1 or more of the major epicardial vessels or their main branches was considered significant. Thereafter, the grade of the thrombolysis in the myocardial infarction flow was determined.12 Statistical analysis Logistic regression analysis was performed to determine the diagnostic potential of left ventricular dyssynchrony as an indicator of LMCAS. The following variables were considered as possible predictors: age, sex, diabetes mellitus, hypertension, smoking, hypercholes-
Electrocardiographic criteria The following electrocardiographic criteria were examined on the admission electrocardiogram: ST-segment elevation ³ 0.5 mm in lead aVR and ST-segment elevation ³ 1.0 mm in lead aVR; 5 anterior (lead V1 th227
Acta Cardiol Sin 2015;31:226-231
Yueh-Juh Lin et al.
RESULTS
terolemia, family history of coronary artery disease, history of myocardial infarction, previous percutaneous coronary intervention, blood pressure, heart rate, Killip class ³ 2,13 peak troponin-I level, electrocardiographic parameters, thrombolysis in myocardial infarction risk score,14 left ventricular mass index, left ventricular wall motion score index, left ventricular ejection fraction, and Tmsv-16SD. The receiver operating characteristic curve analysis was used to determine the optimal cutoff Tmsv-16SD value to predict LMCAS. A p value of 75% stenosis of left main and/or 3-vessel disease with > 90% stenosis in > 2 proximal lesions of the left anterior descending coronary artery and other major epicardial arteries), Kosuge et al.19 demonstrated that an ST-segment elevation ³ 1.0 mm in lead aVR on an admission electrocardiogram is highly suggestive of severe left Acta Cardiol Sin 2015;31:226-231
CONCLUSIONS The 3-dimensional echocardiographic assessment of left ventricular dyssynchrony has the potential to improve the accuracy of noninvasive diagnosis for LMCAS in patients with NSTEMI.
ACKNOWLEDGEMENTS The authors thank Miss Shu-Hua Chen for her en230
Dyssynchrony and Left Main Disease
thusiastic support. The authors also acknowledge statistical assistance provided by the National Translational Medicine and Clinical Trial Resource Center [which is founded by the National Research Program for Biopharmaceuticals (NRPB) at the National Science Council of Taiwan; NSC101-2325-B-002-078] and the Department of Medical Research in the National Taiwan University Hospital.
10.
REFERENCES
11.
1. Lee PW, Zhang Q, Yip GW, et al. Left ventricular systolic and diastolic dyssynchrony in coronary artery disease with preserved ejection fraction. Clin Sci 2009;116:521-9. 2. Ng AC, Tran da T, Allman C, et al. Prognostic implications of left ventricular dyssynchrony early after non-ST elevation myocardial infarction without congestive heart failure. Eur Heart J 2010; 31:298-308. 3. Montal.escot G, Brieger D, Eagle KA, et al. Unprotected left main revascularization in patients with acute coronary syndromes. Eur Heart J 2009;30:2308-17. 4. Nikus K, Järvinen O, Sclarovsky S, et al. Electrocardiographic presentation of left main disease in patients undergoing urgent or emergent coronary artery bypass grafting. Postgrad Med 2011; 123:42-8. 5. Barrabés JA, Figueras J, Moure C, et al. Prognostic value of lead aVR in patients with a first non-ST-segment elevation acute myocardial infarction. Circulation 2003;108:814-9. 6. Sahn DJ, DeMaria A, Kisslo J, Weyman A. Recommendations regarding quantitation in M-mode echocardiography: results of a survey of echocardiographic measurements. Circulation 1978; 58:1072-83. 7. Devereux RB, Reichek N. Echocardiographic determination of left ventricular mass in man. Anatomic validation of the method. Circulation 1977;55:613-8. 8. de Simone G, Daniels SR, Devereux RB, et al. Left ventricular mass and body size in normotensive children and adults: assessment of allometric relations and impact of overweight. J Am Coll Cardiol 1992;20:1251-60. 9. Rosen BD, Fernandes VR, Nasir K, et al. Age, increased left ventricular mass, and lower regional myocardial perfusion are re-
12. 13.
14.
15.
16.
17. 18.
19.
231
lated to greater extent of myocardial dyssynchrony in asymptomatic individuals: the multi-ethnic study of atherosclerosis. Circulation 2009;120:859-66. Lang RM, Bierig M, Devereux RB, et al. Chamber Quantification Writing Group; American Society of Echocardiography’s Guidelines and Standards Committee; European Association of Echocardiography. Recommendations for chamber quantification: a report from the American Society of Echocardiography’s Guidelines and Standards Committee and the Chamber Quantification Writing Group, developed in conjunction with the European Association of Echocardiography, a branch of the European Society of Cardiology. J Am Soc Echocardiogr 2005;18:1440-63. Eek C, Grenne B, Brunvand H, et al. Strain echocardiography and wall motion score index predicts final infarct size in patients with non-ST-segment-elevation myocardial infarction. Circ Cardiovasc Imaging 2010;3:187-94. The TIMI Study Group. The Thrombolysis in Myocardial Infarction (TIMI) trial: phase I findings. N Engl J Med 1985;312:932-6. DeGeare VS, Boura JA, Grines LL, et al. Predictive value of the Killip classification in patients undergoing primary percutaneous coronary intervention for acute myocardial infarction. Am J Cardiol 2001;87:1035-8. Antman EM, Cohen M, Bernink PJ, et al. The TIMI risk score for unstable angina/non-ST elevation MI: a method for prognostication and therapeutic decision making. JAMA 2000;284:835-42. Takaro T, Hultgren HN, Lipton MJ, Detre KM. The VA cooperative randomized study of surgery for coronary arterial occlusive disease II. Subgroup with significant left main lesions. Circulation 1976;54:III 107-17. Chaitman BR, Fisher LD, Bourassa MG, et al. Effect of coronary bypass surgery on survival patterns in subsets of patients with left main coronary artery disease. Report of the Collaborative Study in Coronary Artery Surgery (CASS). Am J Cardiol 1981; 48:765-77. Teirstein PS, Price MJ. Left main percutaneous coronary intervention. J Am Coll Cardiol 2012;60:1605-13. Yamaji H, Iwasaki K, Kusachi S, et al. Prediction of acute left main coronary artery obstruction by 12-lead electrocardiography. ST segment elevation in lead aVR with less ST segment elevation in lead V(1). J Am Coll Cardiol 2001;38:1348-54. Kosuge M, Ebina T, Hibi K, et al. An early and simple predictor of severe left main and/or three-vessel disease in patients with non-ST-segment elevation acute coronary syndrome. Am J Cardiol 2011;107:495-500.
Acta Cardiol Sin 2015;31:226-231
