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Predicting 1-year Mortality After Off-pump Coronary Artery Bypass Grafting in Elderly Patients: Role of Pre-operative Myocardial Infarction and Post-operative Intra-aortic Balloon Pump Use
*Corresponding author: Meera Rajeev, Department of Cardiothoracic Vascular Surgery, All India Institute of Medical Sciences, New Delhi, India. meera0301@gmail.com
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Received: ,
Accepted: ,
How to cite this article: Aditi A, Khan MS, Rajeev M, Singh SP. Predicting 1-year Mortality After Off-pump Coronary Artery Bypass Grafting in Elderly Patients: Role of Pre-operative Myocardial Infarction and Post-operative Intra-aortic Balloon Pump Use. J Card Crit Care TSS. 2026;10:32-6. doi: 10.25259/JCCC_44_2025
Abstract
Objectives:
Coronary artery disease (CAD) remains one of the leading causes of morbidity and mortality in the elderly, with patients over 70 years of age representing a rapidly growing cohort in need of revascularization. Although off-pump coronary artery bypass grafting (OPCAB) has been advocated in this population to reduce the complications associated with cardiopulmonary bypass, several studies have shown that the elderly still experience high rates of 1-year mortality despite the theoretical benefits of the off-pump technique. The current study aimed to determine the outcome of patients more than 70 years of age who underwent elective OPCAB for CAD. The primary objective was to determine the 30-day post-surgery survival. The secondary objectives were to assess the incidence of immediate post-operative complications, intensive care unit (ICU) and hospital stay lengths, and 1-year survival after surgery.
Material and Methods:
This was a single-center, retrospective observational study. Medical records of all patients aged >70 who underwent off-pump coronary artery bypass graft from April 2021 to April 2023 by a single cardiac surgeon at our center were accessed. The following data were collected – baseline demographic data, diagnosis, surgery performed, post-operative bleeding, surgery for mediastinal exploration, inotropic support, blood transfusion, duration of mechanical ventilation, length of ICU and hospital stay, need for intra-aortic balloon pump (IABP), tracheostomy, acute kidney injury (AKI), new-onset arrhythmias, pneumonia, ventilator-associated pneumonia (VAP), sepsis, 30-day, and 1-year mortality.
Results:
Twenty-four patients over 70 years of age underwent OPCAB during the study period. The 30-day survival was 91.6% (22/24), and the 1-year survival was 81.8% (18/22) in patients discharged from the hospital. There were three females and 21 males. There was no statistically significant difference between survivors and non-survivors in terms of age, height, weight, body surface area, duration of mechanical ventilation, drain output, inotropic score, ICU stay, and hospital stay. There was also no significant difference regarding sex, re-exploration, VAP, AKI, need for tracheostomy, and 30-day mortality. Pre-operative myocardial infarction (MI) and the use of IABP in the post-operative period were significantly associated with 1-year mortality after OPCAB.
Conclusion:
Pre-operative MI and post-operative IABP use were both independently associated with increased 1-year mortality in patients more than 70 years of age undergoing OPCAB.
Keywords
Intraaortic balloon pump
Mortality
Off-pump coronary artery bypass grafting
Pre-operative myocardial infarction
Septuagenarians
INTRODUCTION
A prevalent and severe condition in the aging population is coronary artery disease (CAD), with individuals over 70 years increasingly representing a significant proportion of those requiring coronary revascularization. Although off-pump coronary artery bypass grafting (OPCAB) is often considered a safer option in this population to reduce problems associated with cardiopulmonary bypass, several studies have shown that the elderly still experience high rates of one-year mortality despite the theoretical benefits of the off-pump technique.[1] In this setting, the intra-aortic balloon pump (IABP) has long been employed as a circulatory support device that improves coronary perfusion and reduces afterload. However, while early investigations suggested that prophylactic IABP use might stabilize high-risk patients, more recent evidence indicates that IABP insertion may paradoxically contribute to adverse outcomes in elderly patients undergoing OPCAB.
The objective of the current research was to ascertain the outcome of patients aged 70 years or older who received elective OPCAB for CAD. The primary objective was to determine the 30-day post-surgery survival. The secondary objectives were to assess the incidence of immediate postoperative complications, intensive care unit (ICU) and hospital stay lengths, and survival at 1-year post-surgery.
MATERIAL AND METHODS
This was a single-center, retrospective observational study conducted at the All-India Institute of Medical Sciences, New Delhi. After obtaining ethical clearance, the medical records of all patients aged >70 who underwent OPCABG from April 2021 to April 2023 by a single cardiac surgeon at our center were accessed.
All patients aged >70 who underwent elective OPCABG for CAD between April 2021 and 2023 were encompassed in the study. Patients who were lost to follow-up or whose data had been unavailable were excluded from analysis. The following data were collected – baseline demographic data, diagnosis, surgery performed, post-operative bleeding, surgery for mediastinal exploration, inotropic support, blood transfusion, duration of mechanical ventilation, length of ICU as well as hospital stay, required for IABP, tracheostomy, acute kidney injury (AKI), new-onset arrhythmias, pneumonia, ventilator-associated pneumonia (VAP), sepsis, survival rates at 30 days and at 1 year.
AKI was identified based on one or more of the following criteria: A serum creatinine (S.cr) increase of ≥0.3 mg/dL (26.5 μmol/L) within 48 h, a ≥50% increase from baseline within 7 days, or a reduction in urine output to <0.5 mL/kg/h for a minimum of 6 h.[2] Pneumonia was diagnosed by the presence of respiratory symptoms – including sputum production, chest pain, shortness of breath, and cough – along with signs of fever and low oxygen levels, supported by evidence of infiltrates on chest imaging. VAP was diagnosed using the Clinical Pulmonary Infection Score (CPIS). A CPIS score of more than 6 was considered as VAP.[3] The condition of sepsis is life-threatening and is caused by a dysregulated immune response to infection, which results in organ dysfunction. The organ dysfunction is identified by a score increase of two or more points in the Sequential Organ Failure Assessment.[4]
Statistical analysis
The cohort had been divided into two categories based on their 1-year survival rate: Survivors and non-survivors. Data have been provided as proportions for categorical data and as medians with minimum and maximum values for continuous data, as appropriate. Categorical variables were contrasted through Fisher’s exact test, while continuous variables were assessed employing the Wilcoxon rank-sum test. P < 0.05 had been considered statistically significant.
RESULTS
During the period of study, 24 patients over 70 years of age underwent OPCAB. The 30-day survival was 91.6% (22/24), and the 1-year survival was 81.8% (18/22) in patients discharged from the hospital. There were three females and 21 males. Out of 24 patients, 11 had type 2 diabetes mellitus (DM), 10 had hypertension, 1 had hypothyroidism, 2 had chronic obstructive pulmonary disease (COPD), 6 had severe left ventricular (LV) dysfunction, and 3 had a history of myocardial infarction (MI). Survivors and non-survivors showed no statistically significant differences based on age, height, weight, body surface area, duration of mechanical ventilation, drain output, inotropic score, ICU stay, and hospital stay [Table 1]. There was also no significant difference between survivors and non-survivors at 1 year regarding re-exploration, VAP, AKI, need for tracheostomy, incidence of DM, COPD, hypertension, hypothyroidism, severe LV dysfunction, and presence of stent in the pre-operative period. However, the utilization of IABP in the post-operative period and a history of MI before OPCABG are significantly related to 1-year mortality.
| Parameters compared | Survivors at 1 year (n=18) Median (Min, Max) or n(%) | Non-survivors at 1 year (n=6) Median (Min, Max) or n(%) | P-value |
|---|---|---|---|
| Age (years) | 71.5 (70, 81) | 73 (70, 80) | 0.86 |
| Height (cm) | 165 (147, 184) | 162.5 (145, 174) | 0.48 |
| Weight (kg) | 64 (44, 81.3) | 60.5 (38, 75.3) | 0.42 |
| Body surface area (kg/m2) | 1.675 (1.52, 2.01) | 1.67 (1.24, 1.84) | 0.66 |
| Drain output (mL) | 720 (530, 1460) | 630 (450, 965) | 0.19 |
| Duration of mechanical ventilation (hrs) | 14.5 (1, 72) | 42 (9, 75) | 0.08 |
| Inotropic score | 10 (0, 38) | 15 (9, 34) | 0.36 |
| Duration of intensive care unit stay (days) | 4 (2, 25) | 5 (3, 10) | 0.25 |
| Duration of hospital stay (days) | 20.5 (9, 64) | 20 (3, 34) | 0.73 |
| Re-exploration | 0 | 1 (0.2) | 0.25 |
| Ventilator-associated pneumonia | 1 (0.1) | 0 | 0.9 |
| Acute kidney injury | 2 (0.2) | 2 (0.4) | 0.25 |
| Intra-aortic balloon pump | 0 | 3 (0.5) | 0.01 |
| Tracheostomy | 1 (0.1) | 0 | 0.9 |
| Diabetes mellitus | 8 | 3 | 0.7 |
| Hypertension | 7 | 3 | 0.7 |
| Hypothyroidism | 1 | 0 | 0.5 |
| Chronic obstructive pulmonary disease | 2 | 0 | 0.1 |
| Severe left ventricular dysfunction | 3 | 3 | 0.1 |
| Myocardial infarction | 0 | 3 | 0.001 |
| Stent in situ | 1 | 0 | 0.5 |
Mann-Whitney U test has been used to calculate the p-values. P value <0.05 has been considered statistically significant.
DISCUSSION
In this study, we demonstrated that both post-operative IABP use and a history of acute MI before OPCABG were significantly related to increased 1-year mortality. Among our cohort, 12.5% (n = 3) had a history of preoperative MI, and 12.5% required post-operative IABP support in the ICU. Notably, all patients in both groups died within 1 year, underscoring the prognostic significance of these variables.
Conventionally, IABP has been employed to enhance coronary perfusion and decrease afterload, particularly in high-risk patients undergoing cardiac surgery. While early studies supported its prophylactic use,[5] recent meta-analyses have questioned its survival benefit, especially among elderly patients undergoing OPCABG procedures.[6]
Timing and outcomes of IABP insertion
Emerging evidence highlights the crucial role of IABP timing in influencing patient outcomes. Pre-operative insertion may stabilize myocardial function ahead of surgery, whereas intra- and post-operative placement often signals deteriorating hemodynamics and correlates with poorer prognosis. In our study, all patients who received IABP support did so postoperatively and none survived. This pattern aligns with earlier literature: Torchiana et al. reported markedly lower 5- year mortality (13.6%) with pre-operative IABP versus intraoperative (35.7%) and postoperative (35.9%) use.[7] Similarly, Ramnarine et al. observed significantly worse 30-day survival (55.4%) and elevated 1-year mortality with post-operative IABP compared to earlier insertion.[8] These findings suggest that delayed IABP use often occurs after maximal inotropic escalation, at a stage when myocardial dysfunction is likely irreversible.
Individualized and intraoperative approaches
Selective, real-time decision-making may offer superior outcomes to blanket prophylactic strategies. Vettath et al. highlighted the benefits of reactive IABP insertion during OPCAB in response to ischemia, followed by prompt weaning post-anastomosis, which reduces reliance on cardiopulmonary bypass and minimizes complications.[9] This finding aligns with our results, highlighting the importance of personalized intraoperative approaches, particularly for elderly patients who are more susceptible to vascular complications and prolonged recovery. Similarly, Suzuki et al. selectively used preoperative IABP in high-risk patients, achieving favorable outcomes with no IABP-related complications, attributed to meticulous vascular screening and early device removal.[10] However, their study did not evaluate 1-year mortality, a gap that our study addresses.
The elderly paradox: Increased risk despite support
Despite intended hemodynamic support, IABP use in elderly OPCAB patients may paradoxically increase mortality. Age-related vascular stiffness and atherosclerosis heighten the risk of IABP-associated complications, including limb ischemia, aortic dissection, and bleeding.[11] These risks suggest a need for selective use guided by real-time physiology rather than anatomical features alone (e.g., left primary disease). Early weaning protocols, as advocated by Vettath et al., may further mitigate complication rates.[9]
Alternatives to IABP: Physiology over mechanics
Alternative strategies such as levosimendan may yield better outcomes in high-risk patients. Lomivorotov et al.[12] compared intraoperative levosimendan administration with pre-operative IABP in high-risk CABG patients (left ventricular ejection fraction <35%, left main disease). The levosimendan group had significantly higher cardiac index, lower post-operative troponin I, and shorter ICU stays, suggesting superior cardioprotective and hemodynamic benefits.[12] These findings reinforce the value of targeted, physiology-driven interventions over blanket mechanical support.
Impact of MI and surgical timing
A history of recent MI markedly worsens OPCAB outcomes. In our cohort, all patients with prior MI died within 1 year. Thilak et al. linked shorter MI-to-OPCAB intervals with higher mortality due to myocardial instability and susceptibility to ischemia-reperfusion injury during surgical manipulation.[13] In addition, edematous myocardium complicates target vessel identification and increases intraoperative risk. Thielmann et al. further emphasized surgical timing, reporting mortality rates of 10.8% when CABG was implemented in 6 h of STEMI symptom onset, which increased to 23.8% between 7 and 24 h, then declined to 6.7% at 1–3 days, 4.2% at 4–7 days, and declining to just 2.4% when delayed to 8–14 days.[14] Our study did not capture the MI-to-surgery interval, which limits interpretation in this regard and highlights an area for future investigation.
Limitations of the study
The small sample size and single-center retrospective design limit the robustness of conclusions. Second, the timing between MI onset and surgery was not captured, preventing assessment of its impact on mortality.
CONCLUSION
Pre-operative MI and post-operative IABP use were both independently associated with increased 1-year mortality in patients over the age of 70 who undergo OPCAB. However, studies with larger sample sizes are needed to generalize these conclusions.
Ethical approval:
The research/study was approved by the Institutional Review Board at All India Institute of Medical Sciences, number AIIMSA1189, dated 05th May 2024.
Declaration of patient consent:
The authors certify that they have obtained all appropriate patient consent.
Conflicts of interest:
Dr. Sarvesh Pal Singh is on the Editorial Board of the Journal.
Use of artificial intelligence (AI)-assisted technology for manuscript preparation:
The authors confirm that there was no use of artificial intelligence (AI)-assisted technology for assisting in the writing or editing of the manuscript and no images were manipulated using AI.
Financial support and sponsorship: Nil.
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