- Email: [email protected]
Predictors of adverse effects after coronary artery bypass grafting in patients with reduced left ventricular ejection fraction
+
MODEL
Available online at www.sciencedirect.com
ScienceDirect Journal of the Egyptian Society of Cardio-Thoracic Surgery xx (2017) 1e8 http://www.journals.elsevier.com/journal-of-the-egyptian-society-of-cardio-thoracic-surgery/
Original article
Predictors of adverse effects after coronary artery bypass grafting in patients with reduced left ventricular ejection fraction Yasser A. Kamal a,*, Shady E.M. Al-Elwany a, Ahmed M.F. Ghoneim b, Ahmed M.K. El-Minshawy b a b
Department of Cardiothoracic Surgery, Minia University, Egypt Department of Cardiothoracic Surgery, Assiut University, Egypt
Received 16 January 2017; revised 10 February 2017; accepted 13 February 2017 Available online xxx
Abstract Background: To determine adverse outcome and its specific perioperative predictors after coronary artery bypass grafting (CABG) in patients with reduced preoperative ejection fraction (EF). Methods: This study included two propensity-score matched groups, each of 50 patients. Group I included patients with EF <50% and group II included patients with EF 50%. All patients underwent isolated, elective on-pump CABG between November 2014 and October 2016, at Assiut and Minia university hospitals. Preoperative, operative, postoperative and follow-up (6 months) data were collected and analyzed. The primary outcome was early 30 days mortality. Results: Early mortality was 8% in group I and 4% in patients in group II. The proportion of low cardiac output syndrome (LCOS) in group I was significantly higher than group II (44% versus 26%, P ¼ 0.04). At the end of 6 months follow-up, most of patients in group I had significant improvement of EF and NYHA class. On multivariate analysis the significant predictors of outcome in group I were insertion of IABP for early mortality, incomplete revascularization for LCOS, sternal wound infection and LCOS for prolonged hospital stay. Preoperative change in wall motion score following dobutamine stress echocardiography (DSE) had good predictive accuracy for early mortality. Conclusions: Insertion of IABP, incomplete revascularization, wall motion scores on DSE, and postoperative LCOS are significant predictors of adverse outcome after CABG in patients with preoperative EF <50% and viable myocardium. A protocol approach should be established for such patients respecting perioperative risk factors. Copyright © 2017, The Egyptian Society of Cardio-thoracic Surgery. Publishing services by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
Abbreviations: AKI, acute kidney injury; AUC, area under curve; BMI, body mass index; CABG, coronary artery bypass grafting; CAD, coronary artery disease; CI, confidence interval; COPD, chronic obstructive pulmonary disease; DM, diabetes mellitus; DSE, dobutamine stress echocardiography; EF, ejection fraction; EuroSCORE, European system for cardiac operative risk evaluation; IABP, intra aortic balloon pump; LCOS, low cardiac output syndrome; LMS, left main stem; LOS, length of stay; LV, left ventricle; LVEDd, left ventricular end-diastolic diameter; LVEF, left ventricular ejection fraction; LVESd, left ventricular end-systolic diameter; MI, myocardial infarction; MR, mitral regurgitation; NYHA, New York Heart Association; OR, odds ratio; PCI, percutaneous coronary intervention; ROC, receiver operating characteristic curve; SD, standard deviation; SWI, sternal wound infection; TIA, transient ischemic attack; WMSI, wall motion score index. * Corresponding author. Minia University Hospital, Department of Cardiothoracic Surgery, Minia 61519, Egypt. E-mail address: [email protected] (Y.A. Kamal). Peer review under responsibility of The Egyptian Society of Cardio-thoracic Surgery. http://dx.doi.org/10.1016/j.jescts.2017.02.002 1110-578X/Copyright © 2017, The Egyptian Society of Cardio-thoracic Surgery. Publishing services by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Please cite this article in press as: Kamal YA et al., Predictors of adverse effects after coronary artery bypass grafting in patients with reduced left ventricular ejection fraction, Journal of the Egyptian Society of Cardio-Thoracic Surgery (2017), http://dx.doi.org/10.1016/j.jescts.2017.02.002
+ 2
MODEL
Y.A. Kamal et al. / Journal of the Egyptian Society of Cardio-Thoracic Surgery xx (2017) 1e8
Keywords: Coronary artery bypass; Ventricular dysfunction; Complications; Mortality
1. Introduction The decision for coronary artery bypass grafting (CABG) surgery is related to multiple factors mainly degree of angina, function of left ventricle (LV), burden of ischemia, and anatomy of coronaries [1]. Systolic function of LV is known as a predictor of in-hospital death after CABG [2]. The symptomatic benefit of CABG in patients with reduced ejection fraction (EF) is more likely to be obtained when the indication of surgery is angina and not heart failure [3]. Reduced preoperative EF could lead to high incidences of postoperative mortality and morbidity [4]. Multiple perioperative risk factors were reported to affect survival benefit and adverse events after CABG [5]. The aim of the present study was to evaluate and compare adverse outcome between patients undergoing CABG with reduced or normal left ventricular ejection fraction (LVEF), and to determine perioperative risk factors for early mortality and adverse events.
2. Patients and methods This observational study was conducted at departments of Cardiothoracic Surgery in Assiut and Minia University Hospitals, between November 2014 and October 2016. The study included adult patients who underwent isolated, elective, on-pump CABG, and it excluded patients with concomitant valve replacement, previous cardiac surgery, redo-CABG, emergency surgery, hepatic failure, renal failure on dialysis, aneurysm repair, overt peripheral vascular disease, surgery for arrhythmia, repair of ventricular septal perforation, concomitant carotid artery surgery, and absence of myocardial viability. During the study period, 116 out of 122 patients fulfilled our selection criteria, 66 of them had EF 50% and 50 had EF <50%. After propensity-score matching for age, sex and extent of coronary disease, the study included 100 patients who were divided into 2 groups according to their preoperative EF. Group I included 50 patients with EF <50% and group II included another 50 patients with EF 50%. The study considered the ethical principles of Helsinki Declaration. An approval from a research ethics committee and informed consents from patients were obtained. Routine preoperative laboratory and radiological investigations for cardiac surgery were performed for all patients including angiographic and echocardiographic studies. Dobutamine Stress Echocardiography (DSE) was used to evaluate myocardial viability in patients with reduced EF. All patients underwent conventional on-pump CABG with standardized anesthetic technique. Surgeons preferred to use blood cardioplegia in most of cases with combined antegrade and retrograde routes. Echocardiography was repeated in the first week after surgery and at 6th month during the follow-up period. The collected data included preoperative risk factors: Age, female gender, NYHA class, unstable angina, obesity, smoking, chronic pulmonary disease (COPD), hypertension, diabetes mellitus (DM), hypercholesterolemia, chronic systematic diseases, myocardial infarction, left main stem (LMS) disease, transient ischemic attack (TIA) or stroke, time delay in waiting list, and European system for cardiac operative risk evaluation (EuroSCORE). The primary outcome was the proportion of early in-hospital mortality which was defined as mortality during hospital admission in operative room or within 30 days after surgery. The statistical analysis was carried out using SPSS, version 16.0 (SPSS, Chicago, IL, USA). Numeric data were expressed as mean ± standard deviation (SD) and compared by t-student test, while categorical data were expressed as number and percent and compared by Chi-square test. Propensity score matching was done using R Matchlt package version 3.3.2. The KaplaneMeier survival plot was used to illustrate the probability of surviving in a given length of time. The predictive accuracy of numeric continuous variables was estimated according to area under curve (AUC) using receiver operating characteristic (ROC) curve. To determine significant predictors of an adverse event, variables with significant P-value on univariate analysis were further analyzed using multivariate logistic regression. Outcomes with less than 5 events were excluded from analysis. Odds ratio (OR) and 95% confidence intervals (95% CI) were estimated. For each analysis, P-value < 0.05 was considered significant.
Please cite this article in press as: Kamal YA et al., Predictors of adverse effects after coronary artery bypass grafting in patients with reduced left ventricular ejection fraction, Journal of the Egyptian Society of Cardio-Thoracic Surgery (2017), http://dx.doi.org/10.1016/j.jescts.2017.02.002
+
MODEL
Y.A. Kamal et al. / Journal of the Egyptian Society of Cardio-Thoracic Surgery xx (2017) 1e8
3
3. Results Preoperative characteristics of the studied patients were statistically similar except for significantly higher EuroSCORE II, EF, left ventricular end-systolic diameter (LVESd), and grade of diastolic dysfunction in group I (Table 1). Operative characteristics were statistically similar between both groups (Table 2). Early 30 days in-hospital mortality was 8% in group I and 4% in group II, with insignificant difference. In subgroup of patients with EF 35% (n ¼ 7), early mortality was in one patient (14.3%). The median of interval between procedure and mortality was 3.5 days in group I and 5.5 days in group II. The survival probability was 92% in group I and 96% in group II (Fig. 1). The causes of death were cardiogenic shock (3 patients in group I and one patient in group II), multi-organ failure (one patient in group I) and respiratory insufficiency (one patient in group II). There were insignificant differences in postoperative complications (Table 2), except the significantly higher proportion of LCOS in group I (44% versus 26%, P ¼ 0.04). Also, in subgroup of patients with EF 35%, LCOS had statistically significant higher proportion than subgroup of patients with EF >35% (71.4% versus 32.3%, P ¼ 0.03). Most of patients in group I had significant improvement of LVEF 5% at the end of 6 months follow-up than immediately after surgery (80.4% versus 28.3%, P < 0.001). Mean of LVEF increased significantly from 41.36 ± 5.89% before surgery to 44.2 ± 5 in the first week after surgery to 51.4 ± 2.9% at 6 months of follow-up (P < 0.001) (Fig. 2). The preoperative proportion of NYHA class III and IV decreased significantly from 30% to 8.7% (P ¼ 0.03) at end of follow-up. On multivariate analysis, the use of intra aortic balloon pump (IABP) was a significant predictor of early mortality in all patients and in group I (Table 3). Analysis of Receiver operating characteristic (ROC) curves (Fig. 3) revealed that change in wall motion score index (WMSI) on DSE had a good prognostic accuracy after CABG in patients with reduced EF (Area under curve; AUC > 0.80) while change in EF had poor prognostic accuracy (AUC: 60e70). Significant predictors of LCOS (Table 4) included: unstable angina, COPD and chronic hepatitis in all patients, smoking and incomplete revascularization in group I, and unstable angina, COPD and chronic hepatitis in group II.
Table 1 Preoperative characteristics of the studied patients. Variables
Group I (n ¼ 50)
Group II (n ¼ 50)
P-value
Age (years) Female gender BMI (kg/m2) Obesity Smoking DM Hypertension Hypercholesterolemia COPD Chronic hepatitis Stroke or TIA Renal impairment Unstable angina Previous MI Recent MI Previous PCI EuroSCORE II LVEF (%) LVEDd (cm) LVESd (cm) Mild MR Diastolic dysfunction grade Multi-vessel disease Left main disease
55.4 ± 5.6 14 (28%) 29.7 ± 3.8 27 (54%) 32 (64%) 15 (30%) 14 (28%) 2 (4%) 1 (2%) 8 (16%) 2 (4%) 4 (8%) 1 (2%) 4 (8%) 1 (2%) 1 (2%) 0.83 ± 0.17 41.36 ± 5.89 4.99 ± 0.60 3.98 ± 0.56 15 (30%) 1.56 ± 0.57 43 (86%) 6 (12%)
57.8 ± 8.4 9 (18%) 30.2 ± 4.2 26 (52%) 35 (70%) 20 (40%) 11 (22%) 5 (10%) 4 (8%) 4 (8%) 1 (2%) 7 (14%) 4 (8%) 7 (14%) 4 (8%) 2 (4%) 0.64 ± 0.13 61.12 ± 5.79 4.83 ± 0.45 3.26 ± 0.40 11 (22%) 1.22 ± 0.41 38 (76%) 7 (14%)
0.10 0.23 0.52 0.84 0.52 0.29 0.48 0.24 0.16 0.21 0.55 0.33 0.16 0.33 0.16 0.55 <0.001* <0.001* 0.14 <0.001* 0.36 0.001* 0.20 0.76
BMI: Body mass index. DM: Diabetes mellitus, TIA: Transient ischemic attack, COPD: Chronic obstructive pulmonary disease, MI: Myocardial infarction, PCI: Percutaneous coronary intervention. LVEF: Left ventricular ejection fraction. LVEDd: Left ventricular end-diastolic diameter, LVESd: Left ventricular end-systolic diameter. MR: Mitral regurgitation. * Significant difference.
Please cite this article in press as: Kamal YA et al., Predictors of adverse effects after coronary artery bypass grafting in patients with reduced left ventricular ejection fraction, Journal of the Egyptian Society of Cardio-Thoracic Surgery (2017), http://dx.doi.org/10.1016/j.jescts.2017.02.002
+ 4
MODEL
Y.A. Kamal et al. / Journal of the Egyptian Society of Cardio-Thoracic Surgery xx (2017) 1e8
Table 2 Operative and postoperative outcome in the studied patients. Variables
Group I (n ¼ 50)
Group II (n ¼ 50)
P-value
Bypass time (min) Cross-clamp time (min) Incomplete revascularization Use of IABP Early mortality LCOS Reoperation for bleeding AKI Neurological complications SWI
73.5 ± 20 44.4 ± 13.2 21 (42%) 4 (8%) 4 (8%) 22 (44%) 1 (2%) 2 (4%) 2 (4%) 8 (16%)
71.7 ± 18 44.9 ± 10.3 15 (30%) 2 (4%) 2 (4%) 13 (26%) 3 (6%) 1 (2%) 2 (4%) 10 (20%)
0.64 0.93 0.21 0.40 0.40 0.04* 0.30 0.55 1 0.60
IABP: Intra-aortic balloon pump, LCOS: Low cardiac output syndrome, AKI: Acute kidney injury, SWI: sternal wound infection.* Significant difference.
Fig. 1. KaplaneMeier survival plot during 30 days of hospital stay after CABG in the studied groups.
Fig. 2. Mean of left ventricular ejection fraction (LVEF) preoperatively, postoperatively and at end of 6 months of follow after CABG in 46 surviving patients with preoperative reduced LVEF.
Please cite this article in press as: Kamal YA et al., Predictors of adverse effects after coronary artery bypass grafting in patients with reduced left ventricular ejection fraction, Journal of the Egyptian Society of Cardio-Thoracic Surgery (2017), http://dx.doi.org/10.1016/j.jescts.2017.02.002
+
MODEL
Y.A. Kamal et al. / Journal of the Egyptian Society of Cardio-Thoracic Surgery xx (2017) 1e8
5
Table 3 Analysis of perioperative clinical and echocardiographic risk factors associated with early mortality in the studied patients. Variables
All patients: Unstable angina Diastolic dysfunction > grade I Use of IABP Group I: Unstable angina Use of IABP Group II: Unstable angina Use of IABP
Early mortality
6 2 4 4 4 1 3 2 1 1
Univariate P-value
Multivariate OR (95% CI)
P-value
(33.3%) (66.7%) (66.7%)
0.001* 0.03* <0.001*
9.8 (0.31e306) 3.4 (0.44e26) 40 (3.5e457)
0.19 0.23 0.003*
(25%) (75%)
0.001* <0.001*
0 90 (4e2023)
1 0.005*
(50%) (50%)
0.02* 0.001*
6.4 (0.16e245) 24 (0.56e1052)
0.31 0.09
OR: Odds ratio. CI: Confidence interval. IABP: Intra-aortic balloon pump. *Significant predictor.
Fig. 3. Receiver operating characteristic (ROC) curve for predictive accuracy of: (A) low dose wall motion score index (WMSI), (B) peak WMSI, (C) low dose LVEF and (D) peak LVEF determined by dobutamine stress echocardiography in patients with reduced ejection fraction. Areas under curve (AUC) were 0.90, 0.88, 0.60 and 0.70, respectively.
Please cite this article in press as: Kamal YA et al., Predictors of adverse effects after coronary artery bypass grafting in patients with reduced left ventricular ejection fraction, Journal of the Egyptian Society of Cardio-Thoracic Surgery (2017), http://dx.doi.org/10.1016/j.jescts.2017.02.002
+ 6
MODEL
Y.A. Kamal et al. / Journal of the Egyptian Society of Cardio-Thoracic Surgery xx (2017) 1e8
Table 4 Analysis of perioperative clinical and echocardiographic risk factors associated with low cardiac output syndrome (LCOS). Variables
LCOS
All patients: Female gender Unstable angina Smoking COPD Chronic hepatitis Incomplete revascularization Group I: Smoking Incomplete revascularization Group II: Unstable angina COPD Chronic hepatitis
35 4 (11.4%) 4 (11.4%) 29 (82.9%) 4 (11.4%) 9 (25.7%) 18 (51.4%) 22 18 (81.8%) 14 (63.6%) 13 3 (23.1%) 3 (23.1%) 3 (23.1%)
Univariate P-value
Multivariate OR (95% CI)
P-value
0.04* 0.03* 0.01* 0.03* 0.002* 0.01*
0.6 (0.07e5) 10.4 (1e101) 1.8 (0.3e11) 12 (1.1e127) 7.7 (1.7e34) 2.6 (0.96e7)
0.66 0.04* 0.50 0.03* 0.007* 0.058
0.02* 0.006*
4.4 (1e18) 5.2 (1.4e19)
0.03* 0.01*
0.02* 0.02* 0.02*
25.5 (2e307) 25.5 (2e307) 25.5 (2e307)
0.01* 0.01* 0.01*
OR: Odds ratio. CI: Confidence interval. CPD: Chronic obstructive pulmonary disease. *Significant predictor.
Sternal wound infection (SWI) and LCOS were significant predictors of prolonged length of stay (LOS) > 7 days in group I, while only SWI was a significant predictor of prolonged LOS in group II (Table 5). 4. Discussion Selection of patients with reduced EF for CABG is considered as a crucial factor to achieve favorable outcome [6]. The identification of factors associated with operative mortality and morbidity is important for adequate preoperative patient selection and permits evaluation of the quality of care and may help to determine optimal treatment [7,8]. Our selected criterion of viable myocardium determined by DSE was in accordance with meta-analysis performed by Allman et al. [9] which demonstrated improved survival rate after revascularization in patients with LV dysfunction and viable myocardium. Moreover, CABG is beneficial when ischemia is reversible even in patients with severe impairment of LV function [10]. Table 5 Perioperative risk factors and postoperative adverse events associated with prolonged length of hospital stay in survivors. Variables
Hospital stay> 7 days
All patients: NYHA III or IV Smoking COPD Chronic hepatitis Reduced EF LCOS SWI Group I: Smoking LCOS SWI Group II: COPD LCOS SWI
32 8 (25%) 27 (84.4%) 4 (12.5%) 8 (25%) 21 (65.6%) 23 (71.9%) 15 (46.9%) 21 17 (81%) 17 (81%) 7 (33.3%) 11 3 (27.3%) 6 (54.5%) 8 (72.7%)
Univariate P-value
Multivariate OR (95% CI)
P-value
0.02* 0.01* 0.02* 0.01* 0.02* <0.001* <0.001*
0.08 (0.05e2.9) 1.48 (0.29e7.4) 4.42 (0.30e64.5) 1.3 (0.18e9.5) 0.12 (0.02e0.73) 28.3 (5.2e152) 59.5 (7.6e465.5)
0.35 0.63 0.27 0.77 0.02* <0.001* <0.001*
0.04* <0.001* 0.009*
0.81 (0.06e9) 155 (10.7e2253) 71.7 (3.1e1619)
0.87 <0.001* 0.007*
0.01* 0.004* <0.001*
8 (0.32e205.6) 3 (0.30e32.2) 42 (4.9e355.4)
0.20 0.33 0.001*
OR: Odds ratio. CI: Confidence interval. COPD: Chronic pulmonary obstructive disease. LCOS: Low cardiac output syndrome, SWI: Sternal wound infection. *Significant predictor.
Please cite this article in press as: Kamal YA et al., Predictors of adverse effects after coronary artery bypass grafting in patients with reduced left ventricular ejection fraction, Journal of the Egyptian Society of Cardio-Thoracic Surgery (2017), http://dx.doi.org/10.1016/j.jescts.2017.02.002
+
MODEL
Y.A. Kamal et al. / Journal of the Egyptian Society of Cardio-Thoracic Surgery xx (2017) 1e8
7
The early mortality in our study; 4% in patients with EF 50%, 8% in patients with EF <50% and 14.3% in patients with EF 35%, is acceptable and in agreement with recent published data [7,10]. These rates reflect a marked improvement in comparison to older studies which reported higher mortality ranged from 10% to 50% [11]. In the study by Hamad et al. [12], patients with EF <35% had more than 6 times higher risk for early mortality than those with EF of >50% (10.5% versus 1.6%). A study from Egypt by Elassy et al. [13] reported also higher but insignificant early mortality in patients with preoperative EF <35% (5.6% versus 2.4%). The use of intra- or post-operative IABP was a significant predictor of in-hospital mortality in all patients and when EF was <50%. Although the use IABP is important to support failing circulation during CABG, it is well known as a risk factor for mortality [14,15]. It can be associated with complications including stroke, paraplegia, limb ischemia, aortic or iliac dissection bleeding, infection and hemolysis that have an impact on mortality after CABG [16]. Also, patients receiving IABP are already at high risk of increased mortality because of other factors or unstable hemodynamic status [17,18]. Little change of WMSI on DSE had a good predictive accuracy of death after CABG in our patients with reduced EF and viable myocardium. This finding reflects that even in patients with viable myocardium, which is considered as a predictor of survival, little change in WMSI may predict the risk of death after revascularization. Low cardiac output is known as common complication after CABG [19], and reduced EF had been reported as a significant predictor of LCOS following isolated CABG [20]. Our proportion of LCOS increased with reduction of EF; 71.4% when EF 35%, 26% when EF <50% and 44% when EF >50%. Similarly, a study from Egypt by Elassy et al. [13], reported LCOS in 77.5% with EF <35% versus 46.4% with EF >50%. We also demonstrated incomplete revascularization as a predictor of LCOS in patients with EF <50%. Other studies identified incomplete revascularization in addition to impaired LV function (<50%) and on-pump CABG as predictors of LCOS after CABG [19,20]. Incomplete revascularization may result in myocardial damage and hence it has been described to cause LCOS after CABG [19]. Significant predictors of prolonged LOS > 7 days after CABG in our survivor patients with reduced EF <50% were LCOS and sternal wound infection which is accepted in regard to the need for more time to adequately manage these complications before discharge. At the end of 6 months follow-up, our results revealed a significant improvement in EF and NYHA class after CABG in patients with preoperative reduced EF, which support the hypothesis that surgical revascularization preserves already viable and functioning myocardial muscle against later infarction and recruits the hibernating myocardium with amelioration of congestive heart failure and functional class, as reported in an older [21] and recent studies [22]. The main limitations of our study included: 1 e small number of patients that lead to insignificant results of some events; 2 e Cut-off value of reduced EF (<50%) may give inconclusive and non specific results for other cut-off values (20%, 30%, 35% or 40%); 3 e follow-up echocardiography was done only at 6 months after CABG, and thus the observed improvement could not be correlated with long term improvement of LV function; and 4 e similar to multiple studies evaluating adverse outcome after CABG in patients with reduced LVEF, data regarding patency of grafts were not applicable in our study.
5. Conclusions In conclusion, successful results of CABG in patients with EF <50% can be achieved by careful selection of patients and management. Evidence of myocardial viability is necessary to determine beneficial effect of CABG. Postoperative improvement of EF and NYHA functional class reflects the high benefit of CABG in patients with reduced EF. Insertion of IABP, wall motion scores on DSE, incomplete revascularization and postoperative LCOS were significant predictors of adverse outcome. Further studies with large number of patients are recommended to give more valuable conclusions.
Funding sources None.
Please cite this article in press as: Kamal YA et al., Predictors of adverse effects after coronary artery bypass grafting in patients with reduced left ventricular ejection fraction, Journal of the Egyptian Society of Cardio-Thoracic Surgery (2017), http://dx.doi.org/10.1016/j.jescts.2017.02.002
+ 8
MODEL
Y.A. Kamal et al. / Journal of the Egyptian Society of Cardio-Thoracic Surgery xx (2017) 1e8
Conflicts of interest None. References [1] Cesar LAM, Viana CB. Strategy for therapeutic decision medical vs. angioplasty vs. surgery. Rev Soc Cardiol 2014;24(1):17e22. [2] Haxhibeqiri-Karabdic I, Hasanovic A, Kabil E, Straus S. Improvement of ejection fraction after coronary artery bypass grafting surgery in patients with impaired left ventricular function. Med Arch 2014;68(5):332e4. [3] Wijns W, Kolh P, Danchin N. Guidelines on myocardial revascularization: task force on myocardial revascularization of the European Society of Cardiology (ESC) and the European Association for CardioThoracic Surgery (EACTS). Eur Heart J 2010;31:2501e5. [4] Nardi F, Diena M, Caimmi PP. Relationship between left atrial volume and atrial fibrillation following coronary artery bypass grafting. J Card Surg 2012;27:128e35. [5] Soliman Hamad MA, van Straten AH, van Zundert AA, ter Woorst JF, Martens EJ, Penn OC. Preoperative prediction of early mortality in patients with low ejection fraction undergoing coronary artery bypass grafting. J Card Surg 2011;26(1):9e15. [6] Lee S, Chang BC, Yoo KJ, Hong YS, Kang MS. Clinical results of coronary revascularization in left ventricular dysfunction. Circ J 2007;71(12):1862e6. [7] Abdelgawad A, Abdelaziz A, Elshemy A, Salem E, Abdelhamid N. Short term evaluation of clinical outcomes of ischaemic left ventricular dysfunction patients undergoing on pump CABG. J Egypt Soc Cardiothorac Surg 2012;21(4):35e42. [8] Lahtinen J. Predictors of immediate outcome after coronary artery bypass surgery. Acta Univ Ouluensis 2007;D 953:1e105. [9] Allman KC, Shaw LJ, Hachamovitch R, Udelson JE. Myocardial viability testing and impact of revascularization on prognosis in patients with coronary artery disease and left ventricular dysfunction: a meta-analysis. J Am Coll Cardiol 2002;39:1151e8. [10] Abou El Ela ASA, Abdallah AK, Elgamal MA, Amer SM. Coronary artery bypass surgery in patients with poor left ventricular function. J Egypt Soc Cardiothorac Surg 2015;23(1):1e7. [11] Alderman EL, Fisher LD, Litwan P. Results of coronary artery surgery in patients with poor left ventricular function (CASS). Circulation 1983;68:785e95. [12] Hamad MA, van Straten AH, Schonberger JP, ter Woorst JF, de Wolf AM, Martens EJ, et al. Preoperative ejection fraction as a predictor of survival after coronary artery bypass grafting: comparison with a matched general population. J Cardiothorac Surg 2010;5:29. [13] Elassy S, El-Bawab H, Abd El fatah M. Early outcome of coronary artery bypass surgery in patients with poor left ventricular function. J Egypt Soc Cardiothorac Surg 2012;20(3e4):125e31. [14] Davoodi S, Karimi A, Ahmadi SH, Marzban M, Movahhedi N, Abbasi K, et al. Coronary artery bypass grafting in patients with low ejection fraction: the effect of intra-aortic balloon pump insertion on early outcome. Indian J Med Sci 2008;62(8):314e22. [15] Okonta K, Anbarasu M, Kanagarajan K. Intra-aortic balloon pump in coronary artery bypass graft - factors affecting outcome. J West Afr Coll Surg 2011;1(4):28e40. [16] Elahi MM, Chetty GK, Kirke R, Azeem T, Hartshorne R, Spyt TJ. Complications related to intra-aortic balloon pump in cardiac surgery: a decade later. Eur J Vasc Endovasc Surg 2005;29:591e4. [17] Khan I, Mian HM, Iqbal M, Ijaz H, Tufail Z. Prophylactic use of a preoperative intra-aortic balloon pump in patients with severe left ventricular dysfunction undergoing coronary artery bypass grafting. Egypt J Cardiothorac Anesth 2014;8:97e100. [18] Ismail MF, Hamza UA. Coronary artery bypass grafting in patients with severe left ventricular dysfunction. J Egypt Soc Cardiothorac Surg 2011;19(3e4):88e92. [19] Ding W, Ji Q, Shi Y, Ma R. Predictors of low cardiac output syndrome after isolated coronary artery bypass grafting. Int Heart J 2015;56(2):144e9. [20] Sa MP, Nogueira JR, Ferraz PE, Figueiredo OJ, Cavalcante WC, Cavalcante TC, et al. Risk factors for low cardiac output syndrome after coronary artery bypass grafting surgery. Rev Bras Cir Cardiovasc 2012;27:217e23. [21] Elefteriades JA, Tolis Jr G, Levi E, Mills LK, Zaret BL. Coronary artery bypass grafting in severe left ventricular dysfunction: excellent survival with improved ejection fraction and functional state. J Am Coll Cardiol 1993;22:1411e7. [22] Salehi M, Bakhshandeh A, Rahmanian M, Saberi K, Kahrom M, Sobhanian K. Coronary artery bypass grafting in patients with advanced left ventricular dysfunction: excellent early outcome with improved ejection fraction. J Tehran Heart Cent 2016;11(1):6e10.
Please cite this article in press as: Kamal YA et al., Predictors of adverse effects after coronary artery bypass grafting in patients with reduced left ventricular ejection fraction, Journal of the Egyptian Society of Cardio-Thoracic Surgery (2017), http://dx.doi.org/10.1016/j.jescts.2017.02.002
MODEL
Available online at www.sciencedirect.com
ScienceDirect Journal of the Egyptian Society of Cardio-Thoracic Surgery xx (2017) 1e8 http://www.journals.elsevier.com/journal-of-the-egyptian-society-of-cardio-thoracic-surgery/
Original article
Predictors of adverse effects after coronary artery bypass grafting in patients with reduced left ventricular ejection fraction Yasser A. Kamal a,*, Shady E.M. Al-Elwany a, Ahmed M.F. Ghoneim b, Ahmed M.K. El-Minshawy b a b
Department of Cardiothoracic Surgery, Minia University, Egypt Department of Cardiothoracic Surgery, Assiut University, Egypt
Received 16 January 2017; revised 10 February 2017; accepted 13 February 2017 Available online xxx
Abstract Background: To determine adverse outcome and its specific perioperative predictors after coronary artery bypass grafting (CABG) in patients with reduced preoperative ejection fraction (EF). Methods: This study included two propensity-score matched groups, each of 50 patients. Group I included patients with EF <50% and group II included patients with EF 50%. All patients underwent isolated, elective on-pump CABG between November 2014 and October 2016, at Assiut and Minia university hospitals. Preoperative, operative, postoperative and follow-up (6 months) data were collected and analyzed. The primary outcome was early 30 days mortality. Results: Early mortality was 8% in group I and 4% in patients in group II. The proportion of low cardiac output syndrome (LCOS) in group I was significantly higher than group II (44% versus 26%, P ¼ 0.04). At the end of 6 months follow-up, most of patients in group I had significant improvement of EF and NYHA class. On multivariate analysis the significant predictors of outcome in group I were insertion of IABP for early mortality, incomplete revascularization for LCOS, sternal wound infection and LCOS for prolonged hospital stay. Preoperative change in wall motion score following dobutamine stress echocardiography (DSE) had good predictive accuracy for early mortality. Conclusions: Insertion of IABP, incomplete revascularization, wall motion scores on DSE, and postoperative LCOS are significant predictors of adverse outcome after CABG in patients with preoperative EF <50% and viable myocardium. A protocol approach should be established for such patients respecting perioperative risk factors. Copyright © 2017, The Egyptian Society of Cardio-thoracic Surgery. Publishing services by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
Abbreviations: AKI, acute kidney injury; AUC, area under curve; BMI, body mass index; CABG, coronary artery bypass grafting; CAD, coronary artery disease; CI, confidence interval; COPD, chronic obstructive pulmonary disease; DM, diabetes mellitus; DSE, dobutamine stress echocardiography; EF, ejection fraction; EuroSCORE, European system for cardiac operative risk evaluation; IABP, intra aortic balloon pump; LCOS, low cardiac output syndrome; LMS, left main stem; LOS, length of stay; LV, left ventricle; LVEDd, left ventricular end-diastolic diameter; LVEF, left ventricular ejection fraction; LVESd, left ventricular end-systolic diameter; MI, myocardial infarction; MR, mitral regurgitation; NYHA, New York Heart Association; OR, odds ratio; PCI, percutaneous coronary intervention; ROC, receiver operating characteristic curve; SD, standard deviation; SWI, sternal wound infection; TIA, transient ischemic attack; WMSI, wall motion score index. * Corresponding author. Minia University Hospital, Department of Cardiothoracic Surgery, Minia 61519, Egypt. E-mail address: [email protected] (Y.A. Kamal). Peer review under responsibility of The Egyptian Society of Cardio-thoracic Surgery. http://dx.doi.org/10.1016/j.jescts.2017.02.002 1110-578X/Copyright © 2017, The Egyptian Society of Cardio-thoracic Surgery. Publishing services by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). Please cite this article in press as: Kamal YA et al., Predictors of adverse effects after coronary artery bypass grafting in patients with reduced left ventricular ejection fraction, Journal of the Egyptian Society of Cardio-Thoracic Surgery (2017), http://dx.doi.org/10.1016/j.jescts.2017.02.002
+ 2
MODEL
Y.A. Kamal et al. / Journal of the Egyptian Society of Cardio-Thoracic Surgery xx (2017) 1e8
Keywords: Coronary artery bypass; Ventricular dysfunction; Complications; Mortality
1. Introduction The decision for coronary artery bypass grafting (CABG) surgery is related to multiple factors mainly degree of angina, function of left ventricle (LV), burden of ischemia, and anatomy of coronaries [1]. Systolic function of LV is known as a predictor of in-hospital death after CABG [2]. The symptomatic benefit of CABG in patients with reduced ejection fraction (EF) is more likely to be obtained when the indication of surgery is angina and not heart failure [3]. Reduced preoperative EF could lead to high incidences of postoperative mortality and morbidity [4]. Multiple perioperative risk factors were reported to affect survival benefit and adverse events after CABG [5]. The aim of the present study was to evaluate and compare adverse outcome between patients undergoing CABG with reduced or normal left ventricular ejection fraction (LVEF), and to determine perioperative risk factors for early mortality and adverse events.
2. Patients and methods This observational study was conducted at departments of Cardiothoracic Surgery in Assiut and Minia University Hospitals, between November 2014 and October 2016. The study included adult patients who underwent isolated, elective, on-pump CABG, and it excluded patients with concomitant valve replacement, previous cardiac surgery, redo-CABG, emergency surgery, hepatic failure, renal failure on dialysis, aneurysm repair, overt peripheral vascular disease, surgery for arrhythmia, repair of ventricular septal perforation, concomitant carotid artery surgery, and absence of myocardial viability. During the study period, 116 out of 122 patients fulfilled our selection criteria, 66 of them had EF 50% and 50 had EF <50%. After propensity-score matching for age, sex and extent of coronary disease, the study included 100 patients who were divided into 2 groups according to their preoperative EF. Group I included 50 patients with EF <50% and group II included another 50 patients with EF 50%. The study considered the ethical principles of Helsinki Declaration. An approval from a research ethics committee and informed consents from patients were obtained. Routine preoperative laboratory and radiological investigations for cardiac surgery were performed for all patients including angiographic and echocardiographic studies. Dobutamine Stress Echocardiography (DSE) was used to evaluate myocardial viability in patients with reduced EF. All patients underwent conventional on-pump CABG with standardized anesthetic technique. Surgeons preferred to use blood cardioplegia in most of cases with combined antegrade and retrograde routes. Echocardiography was repeated in the first week after surgery and at 6th month during the follow-up period. The collected data included preoperative risk factors: Age, female gender, NYHA class, unstable angina, obesity, smoking, chronic pulmonary disease (COPD), hypertension, diabetes mellitus (DM), hypercholesterolemia, chronic systematic diseases, myocardial infarction, left main stem (LMS) disease, transient ischemic attack (TIA) or stroke, time delay in waiting list, and European system for cardiac operative risk evaluation (EuroSCORE). The primary outcome was the proportion of early in-hospital mortality which was defined as mortality during hospital admission in operative room or within 30 days after surgery. The statistical analysis was carried out using SPSS, version 16.0 (SPSS, Chicago, IL, USA). Numeric data were expressed as mean ± standard deviation (SD) and compared by t-student test, while categorical data were expressed as number and percent and compared by Chi-square test. Propensity score matching was done using R Matchlt package version 3.3.2. The KaplaneMeier survival plot was used to illustrate the probability of surviving in a given length of time. The predictive accuracy of numeric continuous variables was estimated according to area under curve (AUC) using receiver operating characteristic (ROC) curve. To determine significant predictors of an adverse event, variables with significant P-value on univariate analysis were further analyzed using multivariate logistic regression. Outcomes with less than 5 events were excluded from analysis. Odds ratio (OR) and 95% confidence intervals (95% CI) were estimated. For each analysis, P-value < 0.05 was considered significant.
Please cite this article in press as: Kamal YA et al., Predictors of adverse effects after coronary artery bypass grafting in patients with reduced left ventricular ejection fraction, Journal of the Egyptian Society of Cardio-Thoracic Surgery (2017), http://dx.doi.org/10.1016/j.jescts.2017.02.002
+
MODEL
Y.A. Kamal et al. / Journal of the Egyptian Society of Cardio-Thoracic Surgery xx (2017) 1e8
3
3. Results Preoperative characteristics of the studied patients were statistically similar except for significantly higher EuroSCORE II, EF, left ventricular end-systolic diameter (LVESd), and grade of diastolic dysfunction in group I (Table 1). Operative characteristics were statistically similar between both groups (Table 2). Early 30 days in-hospital mortality was 8% in group I and 4% in group II, with insignificant difference. In subgroup of patients with EF 35% (n ¼ 7), early mortality was in one patient (14.3%). The median of interval between procedure and mortality was 3.5 days in group I and 5.5 days in group II. The survival probability was 92% in group I and 96% in group II (Fig. 1). The causes of death were cardiogenic shock (3 patients in group I and one patient in group II), multi-organ failure (one patient in group I) and respiratory insufficiency (one patient in group II). There were insignificant differences in postoperative complications (Table 2), except the significantly higher proportion of LCOS in group I (44% versus 26%, P ¼ 0.04). Also, in subgroup of patients with EF 35%, LCOS had statistically significant higher proportion than subgroup of patients with EF >35% (71.4% versus 32.3%, P ¼ 0.03). Most of patients in group I had significant improvement of LVEF 5% at the end of 6 months follow-up than immediately after surgery (80.4% versus 28.3%, P < 0.001). Mean of LVEF increased significantly from 41.36 ± 5.89% before surgery to 44.2 ± 5 in the first week after surgery to 51.4 ± 2.9% at 6 months of follow-up (P < 0.001) (Fig. 2). The preoperative proportion of NYHA class III and IV decreased significantly from 30% to 8.7% (P ¼ 0.03) at end of follow-up. On multivariate analysis, the use of intra aortic balloon pump (IABP) was a significant predictor of early mortality in all patients and in group I (Table 3). Analysis of Receiver operating characteristic (ROC) curves (Fig. 3) revealed that change in wall motion score index (WMSI) on DSE had a good prognostic accuracy after CABG in patients with reduced EF (Area under curve; AUC > 0.80) while change in EF had poor prognostic accuracy (AUC: 60e70). Significant predictors of LCOS (Table 4) included: unstable angina, COPD and chronic hepatitis in all patients, smoking and incomplete revascularization in group I, and unstable angina, COPD and chronic hepatitis in group II.
Table 1 Preoperative characteristics of the studied patients. Variables
Group I (n ¼ 50)
Group II (n ¼ 50)
P-value
Age (years) Female gender BMI (kg/m2) Obesity Smoking DM Hypertension Hypercholesterolemia COPD Chronic hepatitis Stroke or TIA Renal impairment Unstable angina Previous MI Recent MI Previous PCI EuroSCORE II LVEF (%) LVEDd (cm) LVESd (cm) Mild MR Diastolic dysfunction grade Multi-vessel disease Left main disease
55.4 ± 5.6 14 (28%) 29.7 ± 3.8 27 (54%) 32 (64%) 15 (30%) 14 (28%) 2 (4%) 1 (2%) 8 (16%) 2 (4%) 4 (8%) 1 (2%) 4 (8%) 1 (2%) 1 (2%) 0.83 ± 0.17 41.36 ± 5.89 4.99 ± 0.60 3.98 ± 0.56 15 (30%) 1.56 ± 0.57 43 (86%) 6 (12%)
57.8 ± 8.4 9 (18%) 30.2 ± 4.2 26 (52%) 35 (70%) 20 (40%) 11 (22%) 5 (10%) 4 (8%) 4 (8%) 1 (2%) 7 (14%) 4 (8%) 7 (14%) 4 (8%) 2 (4%) 0.64 ± 0.13 61.12 ± 5.79 4.83 ± 0.45 3.26 ± 0.40 11 (22%) 1.22 ± 0.41 38 (76%) 7 (14%)
0.10 0.23 0.52 0.84 0.52 0.29 0.48 0.24 0.16 0.21 0.55 0.33 0.16 0.33 0.16 0.55 <0.001* <0.001* 0.14 <0.001* 0.36 0.001* 0.20 0.76
BMI: Body mass index. DM: Diabetes mellitus, TIA: Transient ischemic attack, COPD: Chronic obstructive pulmonary disease, MI: Myocardial infarction, PCI: Percutaneous coronary intervention. LVEF: Left ventricular ejection fraction. LVEDd: Left ventricular end-diastolic diameter, LVESd: Left ventricular end-systolic diameter. MR: Mitral regurgitation. * Significant difference.
Please cite this article in press as: Kamal YA et al., Predictors of adverse effects after coronary artery bypass grafting in patients with reduced left ventricular ejection fraction, Journal of the Egyptian Society of Cardio-Thoracic Surgery (2017), http://dx.doi.org/10.1016/j.jescts.2017.02.002
+ 4
MODEL
Y.A. Kamal et al. / Journal of the Egyptian Society of Cardio-Thoracic Surgery xx (2017) 1e8
Table 2 Operative and postoperative outcome in the studied patients. Variables
Group I (n ¼ 50)
Group II (n ¼ 50)
P-value
Bypass time (min) Cross-clamp time (min) Incomplete revascularization Use of IABP Early mortality LCOS Reoperation for bleeding AKI Neurological complications SWI
73.5 ± 20 44.4 ± 13.2 21 (42%) 4 (8%) 4 (8%) 22 (44%) 1 (2%) 2 (4%) 2 (4%) 8 (16%)
71.7 ± 18 44.9 ± 10.3 15 (30%) 2 (4%) 2 (4%) 13 (26%) 3 (6%) 1 (2%) 2 (4%) 10 (20%)
0.64 0.93 0.21 0.40 0.40 0.04* 0.30 0.55 1 0.60
IABP: Intra-aortic balloon pump, LCOS: Low cardiac output syndrome, AKI: Acute kidney injury, SWI: sternal wound infection.* Significant difference.
Fig. 1. KaplaneMeier survival plot during 30 days of hospital stay after CABG in the studied groups.
Fig. 2. Mean of left ventricular ejection fraction (LVEF) preoperatively, postoperatively and at end of 6 months of follow after CABG in 46 surviving patients with preoperative reduced LVEF.
Please cite this article in press as: Kamal YA et al., Predictors of adverse effects after coronary artery bypass grafting in patients with reduced left ventricular ejection fraction, Journal of the Egyptian Society of Cardio-Thoracic Surgery (2017), http://dx.doi.org/10.1016/j.jescts.2017.02.002
+
MODEL
Y.A. Kamal et al. / Journal of the Egyptian Society of Cardio-Thoracic Surgery xx (2017) 1e8
5
Table 3 Analysis of perioperative clinical and echocardiographic risk factors associated with early mortality in the studied patients. Variables
All patients: Unstable angina Diastolic dysfunction > grade I Use of IABP Group I: Unstable angina Use of IABP Group II: Unstable angina Use of IABP
Early mortality
6 2 4 4 4 1 3 2 1 1
Univariate P-value
Multivariate OR (95% CI)
P-value
(33.3%) (66.7%) (66.7%)
0.001* 0.03* <0.001*
9.8 (0.31e306) 3.4 (0.44e26) 40 (3.5e457)
0.19 0.23 0.003*
(25%) (75%)
0.001* <0.001*
0 90 (4e2023)
1 0.005*
(50%) (50%)
0.02* 0.001*
6.4 (0.16e245) 24 (0.56e1052)
0.31 0.09
OR: Odds ratio. CI: Confidence interval. IABP: Intra-aortic balloon pump. *Significant predictor.
Fig. 3. Receiver operating characteristic (ROC) curve for predictive accuracy of: (A) low dose wall motion score index (WMSI), (B) peak WMSI, (C) low dose LVEF and (D) peak LVEF determined by dobutamine stress echocardiography in patients with reduced ejection fraction. Areas under curve (AUC) were 0.90, 0.88, 0.60 and 0.70, respectively.
Please cite this article in press as: Kamal YA et al., Predictors of adverse effects after coronary artery bypass grafting in patients with reduced left ventricular ejection fraction, Journal of the Egyptian Society of Cardio-Thoracic Surgery (2017), http://dx.doi.org/10.1016/j.jescts.2017.02.002
+ 6
MODEL
Y.A. Kamal et al. / Journal of the Egyptian Society of Cardio-Thoracic Surgery xx (2017) 1e8
Table 4 Analysis of perioperative clinical and echocardiographic risk factors associated with low cardiac output syndrome (LCOS). Variables
LCOS
All patients: Female gender Unstable angina Smoking COPD Chronic hepatitis Incomplete revascularization Group I: Smoking Incomplete revascularization Group II: Unstable angina COPD Chronic hepatitis
35 4 (11.4%) 4 (11.4%) 29 (82.9%) 4 (11.4%) 9 (25.7%) 18 (51.4%) 22 18 (81.8%) 14 (63.6%) 13 3 (23.1%) 3 (23.1%) 3 (23.1%)
Univariate P-value
Multivariate OR (95% CI)
P-value
0.04* 0.03* 0.01* 0.03* 0.002* 0.01*
0.6 (0.07e5) 10.4 (1e101) 1.8 (0.3e11) 12 (1.1e127) 7.7 (1.7e34) 2.6 (0.96e7)
0.66 0.04* 0.50 0.03* 0.007* 0.058
0.02* 0.006*
4.4 (1e18) 5.2 (1.4e19)
0.03* 0.01*
0.02* 0.02* 0.02*
25.5 (2e307) 25.5 (2e307) 25.5 (2e307)
0.01* 0.01* 0.01*
OR: Odds ratio. CI: Confidence interval. CPD: Chronic obstructive pulmonary disease. *Significant predictor.
Sternal wound infection (SWI) and LCOS were significant predictors of prolonged length of stay (LOS) > 7 days in group I, while only SWI was a significant predictor of prolonged LOS in group II (Table 5). 4. Discussion Selection of patients with reduced EF for CABG is considered as a crucial factor to achieve favorable outcome [6]. The identification of factors associated with operative mortality and morbidity is important for adequate preoperative patient selection and permits evaluation of the quality of care and may help to determine optimal treatment [7,8]. Our selected criterion of viable myocardium determined by DSE was in accordance with meta-analysis performed by Allman et al. [9] which demonstrated improved survival rate after revascularization in patients with LV dysfunction and viable myocardium. Moreover, CABG is beneficial when ischemia is reversible even in patients with severe impairment of LV function [10]. Table 5 Perioperative risk factors and postoperative adverse events associated with prolonged length of hospital stay in survivors. Variables
Hospital stay> 7 days
All patients: NYHA III or IV Smoking COPD Chronic hepatitis Reduced EF LCOS SWI Group I: Smoking LCOS SWI Group II: COPD LCOS SWI
32 8 (25%) 27 (84.4%) 4 (12.5%) 8 (25%) 21 (65.6%) 23 (71.9%) 15 (46.9%) 21 17 (81%) 17 (81%) 7 (33.3%) 11 3 (27.3%) 6 (54.5%) 8 (72.7%)
Univariate P-value
Multivariate OR (95% CI)
P-value
0.02* 0.01* 0.02* 0.01* 0.02* <0.001* <0.001*
0.08 (0.05e2.9) 1.48 (0.29e7.4) 4.42 (0.30e64.5) 1.3 (0.18e9.5) 0.12 (0.02e0.73) 28.3 (5.2e152) 59.5 (7.6e465.5)
0.35 0.63 0.27 0.77 0.02* <0.001* <0.001*
0.04* <0.001* 0.009*
0.81 (0.06e9) 155 (10.7e2253) 71.7 (3.1e1619)
0.87 <0.001* 0.007*
0.01* 0.004* <0.001*
8 (0.32e205.6) 3 (0.30e32.2) 42 (4.9e355.4)
0.20 0.33 0.001*
OR: Odds ratio. CI: Confidence interval. COPD: Chronic pulmonary obstructive disease. LCOS: Low cardiac output syndrome, SWI: Sternal wound infection. *Significant predictor.
Please cite this article in press as: Kamal YA et al., Predictors of adverse effects after coronary artery bypass grafting in patients with reduced left ventricular ejection fraction, Journal of the Egyptian Society of Cardio-Thoracic Surgery (2017), http://dx.doi.org/10.1016/j.jescts.2017.02.002
+
MODEL
Y.A. Kamal et al. / Journal of the Egyptian Society of Cardio-Thoracic Surgery xx (2017) 1e8
7
The early mortality in our study; 4% in patients with EF 50%, 8% in patients with EF <50% and 14.3% in patients with EF 35%, is acceptable and in agreement with recent published data [7,10]. These rates reflect a marked improvement in comparison to older studies which reported higher mortality ranged from 10% to 50% [11]. In the study by Hamad et al. [12], patients with EF <35% had more than 6 times higher risk for early mortality than those with EF of >50% (10.5% versus 1.6%). A study from Egypt by Elassy et al. [13] reported also higher but insignificant early mortality in patients with preoperative EF <35% (5.6% versus 2.4%). The use of intra- or post-operative IABP was a significant predictor of in-hospital mortality in all patients and when EF was <50%. Although the use IABP is important to support failing circulation during CABG, it is well known as a risk factor for mortality [14,15]. It can be associated with complications including stroke, paraplegia, limb ischemia, aortic or iliac dissection bleeding, infection and hemolysis that have an impact on mortality after CABG [16]. Also, patients receiving IABP are already at high risk of increased mortality because of other factors or unstable hemodynamic status [17,18]. Little change of WMSI on DSE had a good predictive accuracy of death after CABG in our patients with reduced EF and viable myocardium. This finding reflects that even in patients with viable myocardium, which is considered as a predictor of survival, little change in WMSI may predict the risk of death after revascularization. Low cardiac output is known as common complication after CABG [19], and reduced EF had been reported as a significant predictor of LCOS following isolated CABG [20]. Our proportion of LCOS increased with reduction of EF; 71.4% when EF 35%, 26% when EF <50% and 44% when EF >50%. Similarly, a study from Egypt by Elassy et al. [13], reported LCOS in 77.5% with EF <35% versus 46.4% with EF >50%. We also demonstrated incomplete revascularization as a predictor of LCOS in patients with EF <50%. Other studies identified incomplete revascularization in addition to impaired LV function (<50%) and on-pump CABG as predictors of LCOS after CABG [19,20]. Incomplete revascularization may result in myocardial damage and hence it has been described to cause LCOS after CABG [19]. Significant predictors of prolonged LOS > 7 days after CABG in our survivor patients with reduced EF <50% were LCOS and sternal wound infection which is accepted in regard to the need for more time to adequately manage these complications before discharge. At the end of 6 months follow-up, our results revealed a significant improvement in EF and NYHA class after CABG in patients with preoperative reduced EF, which support the hypothesis that surgical revascularization preserves already viable and functioning myocardial muscle against later infarction and recruits the hibernating myocardium with amelioration of congestive heart failure and functional class, as reported in an older [21] and recent studies [22]. The main limitations of our study included: 1 e small number of patients that lead to insignificant results of some events; 2 e Cut-off value of reduced EF (<50%) may give inconclusive and non specific results for other cut-off values (20%, 30%, 35% or 40%); 3 e follow-up echocardiography was done only at 6 months after CABG, and thus the observed improvement could not be correlated with long term improvement of LV function; and 4 e similar to multiple studies evaluating adverse outcome after CABG in patients with reduced LVEF, data regarding patency of grafts were not applicable in our study.
5. Conclusions In conclusion, successful results of CABG in patients with EF <50% can be achieved by careful selection of patients and management. Evidence of myocardial viability is necessary to determine beneficial effect of CABG. Postoperative improvement of EF and NYHA functional class reflects the high benefit of CABG in patients with reduced EF. Insertion of IABP, wall motion scores on DSE, incomplete revascularization and postoperative LCOS were significant predictors of adverse outcome. Further studies with large number of patients are recommended to give more valuable conclusions.
Funding sources None.
Please cite this article in press as: Kamal YA et al., Predictors of adverse effects after coronary artery bypass grafting in patients with reduced left ventricular ejection fraction, Journal of the Egyptian Society of Cardio-Thoracic Surgery (2017), http://dx.doi.org/10.1016/j.jescts.2017.02.002
+ 8
MODEL
Y.A. Kamal et al. / Journal of the Egyptian Society of Cardio-Thoracic Surgery xx (2017) 1e8
Conflicts of interest None. References [1] Cesar LAM, Viana CB. Strategy for therapeutic decision medical vs. angioplasty vs. surgery. Rev Soc Cardiol 2014;24(1):17e22. [2] Haxhibeqiri-Karabdic I, Hasanovic A, Kabil E, Straus S. Improvement of ejection fraction after coronary artery bypass grafting surgery in patients with impaired left ventricular function. Med Arch 2014;68(5):332e4. [3] Wijns W, Kolh P, Danchin N. Guidelines on myocardial revascularization: task force on myocardial revascularization of the European Society of Cardiology (ESC) and the European Association for CardioThoracic Surgery (EACTS). Eur Heart J 2010;31:2501e5. [4] Nardi F, Diena M, Caimmi PP. Relationship between left atrial volume and atrial fibrillation following coronary artery bypass grafting. J Card Surg 2012;27:128e35. [5] Soliman Hamad MA, van Straten AH, van Zundert AA, ter Woorst JF, Martens EJ, Penn OC. Preoperative prediction of early mortality in patients with low ejection fraction undergoing coronary artery bypass grafting. J Card Surg 2011;26(1):9e15. [6] Lee S, Chang BC, Yoo KJ, Hong YS, Kang MS. Clinical results of coronary revascularization in left ventricular dysfunction. Circ J 2007;71(12):1862e6. [7] Abdelgawad A, Abdelaziz A, Elshemy A, Salem E, Abdelhamid N. Short term evaluation of clinical outcomes of ischaemic left ventricular dysfunction patients undergoing on pump CABG. J Egypt Soc Cardiothorac Surg 2012;21(4):35e42. [8] Lahtinen J. Predictors of immediate outcome after coronary artery bypass surgery. Acta Univ Ouluensis 2007;D 953:1e105. [9] Allman KC, Shaw LJ, Hachamovitch R, Udelson JE. Myocardial viability testing and impact of revascularization on prognosis in patients with coronary artery disease and left ventricular dysfunction: a meta-analysis. J Am Coll Cardiol 2002;39:1151e8. [10] Abou El Ela ASA, Abdallah AK, Elgamal MA, Amer SM. Coronary artery bypass surgery in patients with poor left ventricular function. J Egypt Soc Cardiothorac Surg 2015;23(1):1e7. [11] Alderman EL, Fisher LD, Litwan P. Results of coronary artery surgery in patients with poor left ventricular function (CASS). Circulation 1983;68:785e95. [12] Hamad MA, van Straten AH, Schonberger JP, ter Woorst JF, de Wolf AM, Martens EJ, et al. Preoperative ejection fraction as a predictor of survival after coronary artery bypass grafting: comparison with a matched general population. J Cardiothorac Surg 2010;5:29. [13] Elassy S, El-Bawab H, Abd El fatah M. Early outcome of coronary artery bypass surgery in patients with poor left ventricular function. J Egypt Soc Cardiothorac Surg 2012;20(3e4):125e31. [14] Davoodi S, Karimi A, Ahmadi SH, Marzban M, Movahhedi N, Abbasi K, et al. Coronary artery bypass grafting in patients with low ejection fraction: the effect of intra-aortic balloon pump insertion on early outcome. Indian J Med Sci 2008;62(8):314e22. [15] Okonta K, Anbarasu M, Kanagarajan K. Intra-aortic balloon pump in coronary artery bypass graft - factors affecting outcome. J West Afr Coll Surg 2011;1(4):28e40. [16] Elahi MM, Chetty GK, Kirke R, Azeem T, Hartshorne R, Spyt TJ. Complications related to intra-aortic balloon pump in cardiac surgery: a decade later. Eur J Vasc Endovasc Surg 2005;29:591e4. [17] Khan I, Mian HM, Iqbal M, Ijaz H, Tufail Z. Prophylactic use of a preoperative intra-aortic balloon pump in patients with severe left ventricular dysfunction undergoing coronary artery bypass grafting. Egypt J Cardiothorac Anesth 2014;8:97e100. [18] Ismail MF, Hamza UA. Coronary artery bypass grafting in patients with severe left ventricular dysfunction. J Egypt Soc Cardiothorac Surg 2011;19(3e4):88e92. [19] Ding W, Ji Q, Shi Y, Ma R. Predictors of low cardiac output syndrome after isolated coronary artery bypass grafting. Int Heart J 2015;56(2):144e9. [20] Sa MP, Nogueira JR, Ferraz PE, Figueiredo OJ, Cavalcante WC, Cavalcante TC, et al. Risk factors for low cardiac output syndrome after coronary artery bypass grafting surgery. Rev Bras Cir Cardiovasc 2012;27:217e23. [21] Elefteriades JA, Tolis Jr G, Levi E, Mills LK, Zaret BL. Coronary artery bypass grafting in severe left ventricular dysfunction: excellent survival with improved ejection fraction and functional state. J Am Coll Cardiol 1993;22:1411e7. [22] Salehi M, Bakhshandeh A, Rahmanian M, Saberi K, Kahrom M, Sobhanian K. Coronary artery bypass grafting in patients with advanced left ventricular dysfunction: excellent early outcome with improved ejection fraction. J Tehran Heart Cent 2016;11(1):6e10.
Please cite this article in press as: Kamal YA et al., Predictors of adverse effects after coronary artery bypass grafting in patients with reduced left ventricular ejection fraction, Journal of the Egyptian Society of Cardio-Thoracic Surgery (2017), http://dx.doi.org/10.1016/j.jescts.2017.02.002