European Journal of Cardiovascular Medicine

Cardiac surgery constitutes a critical therapeutic intervention for a wide spectrum of cardiovascular diseases, including coronary artery disease, valvular heart disease, and congenital cardiac anomalies. Advancements in surgical techniques, anesthesia, and perioperative care have significantly improved procedural outcomes and survival rates over recent decades. Nonetheless, postoperative complications continue to pose substantial clinical challenges, often offsetting the benefits of surgery. Among these, the requirement for re-exploration following cardiac surgery represents a serious event associated with adverse short-term outcomes and increased resource utilization.

The reported incidence of re-exploration varies across studies but consistently reflects its clinical importance. Re-exploration is most frequently necessitated by postoperative bleeding, cardiac tamponade, or hemodynamic instability. Patients requiring this intervention typically experience longer intensive care stays, higher transfusion requirements, increased risk of organ dysfunction, and greater in-hospital mortality compared to those with uncomplicated postoperative courses. These associations underscore the importance of understanding the determinants and implications of re-exploration after cardiac surgery.

The need for re-exploration appears to be influenced by multiple perioperative factors. Patient characteristics such as advanced age, coexisting comorbidities, coagulation abnormalities, and preoperative anemia have been linked to increased risk. Procedural variables including emergency operations, complex combined procedures, and prolonged cardiopulmonary bypass times further contribute to the likelihood of re-intervention. Systematic identification of these risk factors facilitates the development of preventive strategies and enables early recognition of high-risk patients.

Evidence suggests that both the timing and indication for re-exploration significantly influence patient outcomes. Early re-exploration, particularly for active bleeding, may reduce postoperative complications and mortality when compared with delayed intervention or reoperations performed for hemodynamic compromise or tamponade. Conversely, delays beyond the initial postoperative period have been associated with increased transfusion requirements, longer intensive care stays, and poorer overall prognosis, highlighting the critical role of timely surgical decision-making.

Variability in re-exploration rates across institutions reflects differences in surgical practices, perioperative protocols, and postoperative care pathways. Standardized intraoperative hemostasis checklists, structured protocols for the management of postoperative bleeding, and multidisciplinary decision-making frameworks have been associated with improved patient outcomes and lower re-exploration rates in certain settings. These findings emphasize the potential impact of institutional practices on both the incidence of re-exploration and its prognostic implications.

Despite the recognition of re-exploration as a critical determinant of postoperative morbidity and mortality, comprehensive data encompassing its incidence, risk factors, timing, and prognostic impact remain limited in many healthcare settings. The present study was designed to evaluate the incidence and risk factors for re-exploration following cardiac surgery, assess its prognostic implications for mortality and morbidity, and explore postoperative outcomes associated with this intervention in a tertiary care environment.

Aims and Objectives

Aim
To evaluate the incidence, peri-operative determinants, and prognostic impact of re-exploration after cardiac surgery in a tertiary care setting.

Objectives

1. To determine the incidence and peri-operative risk factors associated with re-exploration after cardiac surgery.
2. To assess the prognostic impact of re-exploration on in-hospital mortality and major postoperative morbidity

Study Design and Setting

This study was conducted as a single-institution, prospective observational study at the Department of Cardiovascular and Thoracic surgery, Government Rajaji Hospital, Madurai Medical College, Madurai. The total study duration was from June 2023 to May 2024.

Study Population

The study population included all patients who underwent cardiac surgery—both on-pump and off-pump procedures—at the study center during the data collection period.

Inclusion and Exclusion Criteria

All patients undergoing cardiac surgery during the study period were eligible for inclusion. Patients who did not consent to participate and those whose cardiac procedure was deferred after sternotomy were excluded from the study.

Sample Size and Sampling Technique

Given the low incidence of re-exploration following cardiac surgery, a convenience sampling technique was employed. All eligible patients who underwent cardiac surgery and required re-exploration during the study period were included in the analysis.

Study Procedure

Data on baseline demographics, preoperative laboratory parameters, index cardiac procedures, intraoperative characteristics, indications and timing of re-exploration, postoperative morbidity parameters, and mortality outcomes were collected prospectively using a structured data collection proforma. Patients were followed until hospital discharge, and clinical outcomes were recorded in detail for analysis.

Statistical Analysis

Data were entered into Microsoft Excel and analyzed using Statistical Package for Social Sciences (SPSS) software version 26.0. Continuous variables were expressed as mean ± standard deviation (SD), whereas categorical variables were presented as frequencies and percentages. Comparisons between survivors and non-survivors were performed using the Student’s t-test for continuous variables and the Chi-square test for categorical variables. A p-value < 0.05 was considered statistically significant.

Ethical Consideration

Institutional Ethics Committee approval was obtained before initiating the study. Informed written consent was taken from all participants prior to enrollment, and patient confidentiality was strictly maintained throughout the study period.

Table 1. Baseline Demographics and Pre-operative Laboratory Profile of Re-exploration Cohort (n=22)

Chart 1. Gender distribution

Out of 384 cases during the study period, 22 cases had reexploration. The incidence is 5.73% (95% CI = 3.63 to 8.55%). The mean age of the study cohort was 48.82 years (SD = 12.75), with a predominance of males (n = 15, 68.2%) compared to females (n = 7, 31.8%). The mean body mass index (BMI) was 21.63 kg/m² (SD = 4.45). Preoperative hematological and biochemical parameters showed a mean hemoglobin of 12.89 g/dL (SD = 1.66), platelet count of 261.82 × 10³/µL (SD = 74.15), urea of 27.73 mg/dL (SD = 14.09), creatinine of 1.10 mg/dL (SD = 0.24), albumin of 3.96 g/dL (SD = 0.48), and total bilirubin of 0.75 mg/dL (SD = 0.40). Coagulation parameters demonstrated a mean prothrombin time (PT) of 13.27 seconds (SD = 1.79), INR of 0.96 (SD = 0.13), and activated partial thromboplastin time (aPTT) of 26.96 seconds (SD = 5.62). The mean hematocrit was 27.58% (SD = 7.93), and the mean lactate level was 3.33 mmol/L (SD = 1.85). Among the study participants, 18 (81.8%) were on aspirin, whereas only 4 (18.2%) had received preoperative heparin. (Table 1) (Chart 1)

Table 2. Index Cardiac Procedures and Primary Diagnoses Among Patients Undergoing Re-exploration

Among patients undergoing re-exploration, the most common primary diagnosis was coronary artery disease (CAD) in various forms, accounting for 14 patients (63.6%), followed by rheumatic heart disease (RHD) in 6 patients (27.3%). Isolated atrial septal defect (ASD) and severe aortic stenosis (AS) were each observed in 1 patient (4.5%). Regarding the index cardiac procedures, coronary artery bypass grafting (CABG) was the predominant surgery performed in 14 patients (63.6%), followed by mitral valve replacement (MVR) in 4 patients (18.2%). Combined MVR with CABG, aortic valve replacement (AVR), intracardiac repair (ICR), and ICR with annuloplasty were each performed in 1 patient (4.5%). (Table 2)

Table 3. Intra-operative Characteristics: OT Duration, CPB/Cross-Clamp Times, Lactate, Transfusions, and Blood Loss

The mean operating theatre (OT) duration for the study cohort was 3.95 hours (SD = 0.95), with a mean cardiopulmonary bypass (CPB) time of 125.44 minutes (SD = 43.31) and a mean cross-clamp time of 90.33 minutes (SD = 39.48). The mean intra-operative lactate level was 3.33 mmol/L (SD = 1.85). Regarding transfusion requirements, 4 patients (18.2%) received 1 unit, 7 patients (31.8%) received 2 units, 4 patients (18.2%) received 3 units, 3 patients (13.6%) received 4 units, and 1 patient (4.5%) received 5 units of blood intra-operatively. The mean blood loss was 1419.05 ml (SD = 960.53). (Table 3)

Table 4. Re-exploration Triggers, Location, and Timing (Indication, ICU vs OT, Hours to Return to Theatre)

Chart 2. Indication for Re-exploration

The most common indication for re-exploration was postoperative bleeding, reported in 16 patients (72.7%), followed by ventricular tachycardia (VT)/ ventricular arrhythmia in 6 patients (27.3%). Re-exploration was performed in the operation theatre (OT) for 13 patients (59.1%), whereas 9 patients (40.9%) underwent the procedure in the intensive care unit (ICU). Regarding timing, 6 patients (27.3%) required re-exploration within 2 hours, 5 patients (22.7%) between 2–6 hours, 3 patients (13.6%) between 6–12 hours, 3 patients (13.6%) between 12–24 hours, and 5 patients (22.7%) after 24 hours of the initial surgery. (Table 4) (Chart 2).

Table 5. Post-operative Course and Morbidity: Ventilation/Extubation Status, ICU Stay, ICD Days, and Transfusion Requirements

Following re-exploration, 13 patients (59.1%) remained intubated, whereas 9 patients (40.9%) were extubated within 24 hours. The mean ICU stay was 3.64 days (SD = 2.68), and the mean duration of intercostal drainage (ICD) was 5.00 days (SD = 4.92). Post-operative transfusion requirements varied, with 3 patients (13.6%) receiving 1 unit, 2 patients (9.1%) receiving 3 units, 7 patients (31.8%) receiving 4–10 units, and 10 patients (45.5%) requiring more than 10 units of blood products. (Table 5)

Table 6. Prognostic Impact: Comparison of Alive vs Death Groups (Risk Factors and Outcomes with p-values)

*-statistically significant

Chart 3. Mortality among participants

Comparison between alive (n = 7) and death (n = 15) groups showed no significant differences in demographic or most preoperative laboratory parameters, including age, BMI, hemoglobin, platelet count, renal function, liver parameters, or coagulation profile (all p > .05). However, several variables demonstrated significant associations with mortality. Mean blood loss was significantly lower among those who died compared to survivors (1135.71 ± 980.67 ml vs. 1985.71 ± 655.56 ml, p = .03), and postoperative transfusion requirements were also lower in the death group (9.29 ± 8.60 units vs. 22.86 ± 18.16 units, p = .02). Furthermore, the mean number of ICD days was significantly shorter among those who died (2.67 ± 2.94 days vs. 10.00 ± 4.65 days, p = .001). Patients requiring re-exploration for ventricular tachycardia (VT) (40.0%, p = .04) and those re-explored in the ICU rather than the operation theatre (60.0%, p = .001) had significantly higher mortality. (Table 6) (Chart 3).

In the present study, coronary artery disease accounted for most cases undergoing re-exploration (63.6%), with coronary artery bypass grafting representing the predominant procedure (63.6%). Similar procedural profiles have been reported by Tran et al. [6], who noted that although valvular and combined procedures carry a higher relative risk of re-exploration, CABG constitutes the largest absolute proportion due to higher case volumes. Ali et al. [10] also demonstrated that re-exploration was consistently associated with adverse early outcomes across mixed CABG and valve cohorts. Likewise, Heimisdottir et al. [3] found that the early risk associated with re-exploration attenuated over time, especially in mixed CABG/valve populations. Dimberg et al. [13] further reported increased rates of reintervention among re-explored CABG patients, reinforcing the clinical implications of our procedural distribution.

Survivors in this cohort had higher measured blood loss and greater transfusion requirements than non-survivors, a finding contrasting with Haneya et al. [7], who linked heavier bleeding and transfusion burden to increased mortality, especially with delayed re-exploration. Tran et al. [6] similarly associated re-operation with increased mortality, perioperative complications, and resource use, emphasizing the impact of bleeding severity. Stroo et al. [9] showed that while re-exploration itself was not consistently associated with long-term mortality, transfusion burden — particularly with packed red blood cells — independently predicted adverse outcomes. Fröjd et al. [15] likewise demonstrated that higher transfusion requirements correlated with worse long-term survival, highlighting the complexity of interpreting transfusion-related risk.

Bleeding was the most common trigger for re-exploration (72.7%), and ICU-based procedures were associated with higher mortality in this study. Shou et al. [8] demonstrated that delays beyond 4–12 hours significantly increased morbidity and mortality, reinforcing the importance of early surgical intervention. Haneya et al. [7] also reported that mortality rose sharply with delayed re-exploration and in cases with cardiac tamponade. Tran et al. [6] identified prolonged time to re-exploration as an independent predictor of death, while Alshoubaki et al. [5] observed that ICU-based re-openings were linked to older age, higher transfusion requirements, and increased mortality, consistent with the present findings.

This study found no significant differences in baseline laboratory parameters between survivors and non-survivors, whereas mortality clustered around VT indication and ICU location. In contrast, Deng et al. [2] identified elevated creatinine, lactate levels, and longer operative times as independent predictors of in-hospital mortality. Elassal et al. [4] similarly associated high EuroSCORE, urgent priority status, and low platelet counts with increased re-exploration risk and adverse outcomes. Alström et al. [11] reported that preoperative hematologic variables and antithrombotic exposure predicted re-exploration risk after CABG, while Rodrigues et al. [14] documented the relationship between bleeding-related reoperation and subsequent postoperative complications.

The present cohort demonstrated high early mortality among re-explored patients, particularly when ICU location and VT indication were involved. Ohmes et al. [1] reported that re-exploration was an independent predictor of in-hospital mortality and major adverse events. Heimisdottir et al. [3] observed a nearly four-fold increase in adjusted early mortality among re-explored patients, even after controlling for confounders. Tran et al. [6] confirmed increased odds of perioperative complications and mortality in large administrative datasets, while Cancelli et al. [16] emphasized the early mortality burden associated with re-exploration across multiple studies in their meta-analysis.

The association between ICU re-exploration and mortality in this study underscores the importance of institutional systems and surgical logistics. Elassal et al. [4] demonstrated that structured intraoperative checklists and standardized bleeding algorithms reduced re-exploration rates and improved outcomes. Tran et al. [6] documented wide inter-hospital variability in take-back rates and failure-to-rescue, linking high-performing centers with lower mortality. Shou et al. [8] further highlighted the benefits of early return-to-theatre protocols in reducing adverse outcomes. Heimisdottir et al. [3] and Stroo et al. [9] also observed that while early mortality increased with re-exploration, long-term survival differences diminished after adjustment for patient factors and transfusion burden.

Limitations

The study was limited by its small sample size, which may have reduced the power to detect significant associations across all peri-operative variables. Additionally, its single-center design limits generalizability to other settings.

This study highlights that re-exploration after cardiac surgery is associated with significant early mortality and morbidity, particularly when procedures are performed in the ICU setting or triggered by ventricular tachycardia. While baseline laboratory and demographic parameters showed no significant differences between survivors and non-survivors, factors such as timing, location of re-exploration, and postoperative course were strongly linked to outcomes. These findings reinforce the prognostic weight of prompt surgical intervention and optimized peri-operative management in mitigating the risks associated with re-exploration.

Based on these results, the implementation of standardized institutional protocols for early recognition and management of postoperative bleeding and hemodynamic instability is strongly recommended. Expedited return-to-theatre pathways, structured hemostasis checklists, and multidisciplinary decision-making frameworks should be prioritized to reduce delays and improve patient outcomes. Future multicenter, prospective studies with larger cohorts are warranted to validate these findings and develop risk prediction models to guide clinical decision-making.

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