European Journal of Cardiovascular Medicine

Coronary artery disease (CAD) remains a major contributor to perioperative cardiac morbidity across the world, particularly in aging populations where multiple risk factors such as hypertension, diabetes and dyslipidemia coexist ^[1]. Advances in medical therapy and coronary interventions have increased the number of patients with stable CAD presenting for noncardiac surgery, yet these individuals continue to face a higher risk of myocardial ischemia, arrhythmias and perioperative cardiac events compared with the general surgical population ^[2]. Even modest alterations in heart rate and blood pressure can impair coronary perfusion, especially in patients with fixed coronary stenosis or impaired ventricular function ^[3]. This makes the choice of anaesthetic technique an important determinant of intraoperative safety.

Regional anaesthesia is often preferred for lower-limb procedures because it provides effective surgical anaesthesia, reduces the stress response, limits thrombotic complications and avoids airway manipulation that may provoke tachycardia or hypertension ^[4]. However, the hemodynamic consequences of regional techniques differ considerably. Spinal anaesthesia (SA) induces a rapid sympathectomy that reduces systemic vascular resistance and venous return. In healthy individuals, compensatory mechanisms may maintain adequate perfusion, but in CAD patients, these abrupt shifts may reduce coronary blood flow and increase myocardial oxygen demand, thereby precipitating ischemia ^[5]. SA is also associated with a higher incidence of hypotension and bradycardia, particularly when high sensory levels are achieved or when patients are volume-depleted or elderly ^[6].

Combined spinal epidural anaesthesia (CSEA) has been proposed as a more controlled alternative in high-risk cardiovascular patients. The technique combines the rapid onset of a low-dose spinal block with the flexibility to extend the block via an epidural catheter. This allows the anaesthesiologist to avoid a sudden sympathectomy and instead titrate the block gradually to achieve a stable hemodynamic profile ^[7]. The ability to administer incremental epidural doses is particularly useful in patients with compromised autonomic reserve, where even small reductions in systemic vascular resistance may adversely affect coronary perfusion ^[8]. Several studies in orthopaedic, obstetric and urologic populations have shown that CSEA may provide smoother cardiovascular trends compared with SA, with fewer episodes of significant hypotension and reduced vasopressor requirements ^[9,10]

Despite these potential advantages, there is limited evidence directly comparing SA and CSEA specifically in patients with documented CAD. Much of the available literature includes mixed populations or focuses on elderly patients without stratifying cardiac disease severity. Furthermore, variability exists in block levels, drug doses, monitoring strategies and definitions of hemodynamic instability. Given the increasing prevalence of CAD patients undergoing lower-limb surgeries and the clinical importance of optimizing hemodynamic control, a focused comparative evaluation of SA and CSEA in this group is warranted. Understanding real-time cardiovascular responses to each technique may guide safer anaesthetic decision-making and improve perioperative outcomes in patients with compromised coronary physiology.

Study Design

This study was designed as a prospective comparative clinical study that evaluated hemodynamic stability in patients with coronary artery disease undergoing lower limb surgery under regional anaesthesia. Two commonly used neuraxial techniques, spinal anaesthesia and combined spinal epidural anaesthesia, were compared in real-time intraoperative settings. Ethical clearance was obtained from the Institutional Ethics Committee of Kakatiya Medical College, Hanumakonda. All eligible participants were informed about the procedures and written consent was collected before enrolment.

Study Setting and Duration

The study was carried out in the Department of Anaesthesiology, Kakatiya Medical College and Mahatma Gandhi Memorial (MGM) Hospital, Hanumakonda, Telangana. MGM function as major tertiary care centre with well-equipped operating theatres and cardiology support systems at KMC-PMSSY. The data collection period extended from January 2023 to December 2024.

Study Population

Patients with a documented diagnosis of stable coronary artery disease who were scheduled for elective lower limb orthopaedic or vascular surgeries under regional anaesthesia were considered for inclusion. The diagnosis of CAD was confirmed through previous cardiology records, angiographic reports, stress test results or echocardiographic evaluation. All selected patients underwent standardised preanaesthetic assessment before allocation into groups.

Inclusion Criteria

Adults aged 40 to 80 years, belonging to the ASA physical status II or III category and diagnosed with stable CAD, were included in the study. Only those scheduled for elective lower limb surgery and able to provide informed consent were enrolled.

Exclusion Criteria

Patients were excluded if they had decompensated heart failure, severe valvular lesions, uncontrolled arrhythmias, contraindications to neuraxial blocks, local infection at the puncture site, coagulopathy, known allergy to local anaesthetic agents or any neurological condition that could interfere with assessment of block height or motor function. Patients who were unable to tolerate regional anaesthesia or who required conversion to general anaesthesia were also excluded from final analysis.

Sample Size and Group Allocation

Sixty patients who met the eligibility criteria were enrolled. They were assigned into two groups of equal size, with thirty receiving spinal anaesthesia and thirty receiving combined spinal epidural anaesthesia. Allocation followed an alternating sequence at the point of enrolment to ensure equal distribution across both study arms.

Preoperative Evaluation

All participants underwent thorough preoperative evaluation that included detailed medical history, the severity of coronary artery disease, history of angina or revascularisation, medications, exercise tolerance and previous anaesthetic exposure. Routine investigations included blood counts, renal function tests, electrolytes and coagulation profile. A baseline electrocardiogram was recorded for all patients, and echocardiography or angiographic details were reviewed where available. Cardiac medications such as beta blockers, nitrates, antiplatelets and statins were continued as advised by the cardiology team. Baseline blood pressure, heart rate, oxygen saturation and mean arterial pressure were measured in the preoperative area.

Anaesthesia Techniques

Spinal Anaesthesia Group

Patients in the spinal anaesthesia group received the block in either the sitting or lateral position. After securing an intravenous line and administering preload with isotonic crystalloids, the lumbar puncture was performed under strict aseptic conditions at either the L3 to L4 or L4 to L5 level using a 25-gauge spinal needle. Clear cerebrospinal fluid confirmation preceded the injection of 0.5 percent hyperbaric bupivacaine. The local anaesthetic dose was adjusted to achieve a sensory block appropriate for the surgical procedure. No epidural catheter was inserted in this group.

Combined Spinal Epidural Group

Patients in the combined spinal epidural group were prepared similarly. An epidural puncture was performed using an 18-gauge Tuohy needle, and the epidural space was identified using the loss-of-resistance technique. A long spinal needle was then introduced through the epidural needle to administer a low dose of intrathecal hyperbaric bupivacaine. After completing the intrathecal injection, an epidural catheter was advanced 3 to 5 cm into the epidural space. Incremental doses of diluted local anaesthetic were administered through the catheter to extend or maintain the sensory block in a controlled manner.

Intraoperative Monitoring

Continuous monitoring was performed using ECG, pulse oximetry and noninvasive blood pressure measurements. Baseline vitals were recorded before the block. Blood pressure and heart rate were documented at 1, 3, 5, 10, 15, 20, 30, 45 and 60 minutes after block administration. Hypotension was defined as a fall in systolic blood pressure of at least 20 percent from baseline. Bradycardia was defined as heart rate less than 50 beats per minute. Any ST segment deviation or T wave abnormality suggestive of myocardial ischemia was noted.

Intraoperative Management

All patients received intravenous fluids as per standard clinical practice. Hypotension was managed with intravenous mephentermine or phenylephrine depending on the associated heart rate response. Bradycardia was treated with intravenous atropine. Chest discomfort or any ECG abnormality was immediately evaluated and, if required, discussed with the cardiology team. Sensory block level was checked periodically with pinprick testing, while motor block was assessed using the Bromage scale. Patient comfort and adequacy of anaesthesia were evaluated throughout the surgery.

Outcome Measures

The primary outcome of interest was hemodynamic stability, which was determined by the pattern of blood pressure and heart rate changes and the need for vasopressor support. Secondary outcomes included the incidence of bradycardia, any ECG evidence of ischemia, the level of sensory block achieved, onset time of the block and complications related to the procedure.

Data Collection

All perioperative observations were recorded prospectively using a structured data sheet designed for the study. The sheet included demographic details, medical history, anaesthesia technique, sensory and motor block characteristics, hemodynamic variables at each time point, vasopressor use, ECG changes and any adverse events. Data entry was performed immediately after each measurement to ensure accuracy and completeness.

Statistical Analysis

All collected data were compiled and analysed using standard statistical software. Continuous variables such as blood pressure and heart rate were expressed as mean and standard deviation. Categorical variables such as incidence of hypotension and bradycardia were presented as frequencies and percentages. The two groups were compared using the Student t test for continuous variables and the chi square test for categorical variables. A p value less than 0.05 was considered statistically significant for all analyses.

Baseline Characteristics

All sixty patients enrolled completed the study and were included in the final analysis. There were no significant differences between the spinal anaesthesia (SA) and combined spinal epidural anaesthesia (CSEA) groups with respect to age, sex distribution, body mass index, duration of coronary artery disease, or associated comorbidities. Mean age was comparable between groups (SA: 63.4 ± 7.8 years vs CSEA: 64.1 ± 8.3 years, p = 0.72) (Table 1). Hypertension, diabetes and previous myocardial infarction were distributed evenly. Baseline hemodynamic parameters such as systolic blood pressure, diastolic blood pressure and heart rate showed no statistically significant variation.

Table 1: Baseline Demographic and Clinical Characteristics

                                    (*Chi square test)

Hemodynamic Profiles over Time

The SA group demonstrated a more abrupt fall in blood pressure during the first 10–15 minutes following intrathecal injection. In contrast, the CSEA group showed a more gradual and controlled hemodynamic decline. The greatest divergence in mean arterial pressure (MAP) was noted at the 10-minute interval, where the SA group exhibited a mean reduction of −24.5 ± 6.1 mmHg compared with −11.2 ± 4.8 mmHg in the CSEA group (t = 9.01, p < 0.001) (Figure 1).

Heart rate remained relatively stable in both groups. Transient bradycardia was observed more frequently in the SA group but did not reach statistical significance.

Incidence of Hypotension and Vasopressor Use

Hypotension was significantly more common after spinal anaesthesia. Fourteen patients (46.7 percent) in the SA group experienced hypotension compared with only five patients (16.7 percent) in the CSEA group (χ² = 6.67, p = 0.01). Additionally, the onset of hypotension occurred earlier in the SA group (median time: 5 minutes) than in the CSEA group (median time: 15 minutes).

Vasopressor support was required more frequently in the SA group (40 percent) compared with the CSEA group (13.3 percent), which was statistically significant (χ² = 6.04, p = 0.014). The total cumulative dose of mephentermine was also markedly higher in the SA group.

Sensory Block Characteristics

The onset of sensory block was significantly faster in the SA group (4.1 ± 0.9 minutes) compared with the CSEA group (7.6 ± 1.5 minutes; p < 0.001). Both groups achieved comparable maximum sensory levels suitable for surgery; however, the CSEA group benefited from a more controlled extension of the block, which promoted greater cardiovascular stability.

Motor block, assessed using Bromage scale, was adequate in all patients. No differences were observed in block regression times between groups.

Intraoperative Hemodynamic Events and Management

The comparison of intraoperative hemodynamic events between the SA and combined CSEA groups demonstrates clear and meaningful differences in cardiovascular stability.

The most striking finding is the higher occurrence of hypotension in the SA group. Nearly half of the patients who received spinal anaesthesia (46.7 percent) developed hypotension, while the incidence was significantly lower in the CSEA group at 16.7 percent. The chi square value of 6.67 with a p value of 0.01 confirms that this difference is statistically significant. This pattern is consistent with the expected physiological response; SA often produces an abrupt sympathetic blockade, whereas CSEA allows a more gradual spread of anaesthetic effect through slow epidural titration. The CSEA approach therefore appears to protect patients from sudden drops in vascular tone, which is particularly relevant in individuals with coronary artery disease.

Bradycardia was observed in both groups, but the difference did not reach statistical significance. Five patients in the SA group experienced a fall in heart rate, compared with two in the CSEA group. Although numerically higher in the SA group, the chi square test result (1.46) and p value (0.23) indicate that chance could explain this variation. In clinical terms, both techniques produced occasional bradycardia, and the episodes were transient and easily managed.

The requirement for vasopressor support further emphasizes differences in hemodynamic stability. Forty percent of patients in the SA group needed pharmacological intervention to maintain blood pressure, whereas only 13.3 percent of patients in the CSEA group required a vasopressor. This difference is statistically significant (χ² = 6.04, p = 0.014), reflecting the more controlled hemodynamic profile seen with the combined technique. For patients with limited cardiac reserve, reducing the need for vasopressors is a valuable advantage.

The magnitude of MAP reduction during the early post-block phase also differed substantially. At 10 minutes, the SA group experienced a steep fall in MAP averaging −24.5 mmHg, compared with a more modest decline of −11.2 mmHg in the CSEA group. The large t value of 9.01 and the p value below 0.001 highlight that this difference is robust and unlikely to be due to random variation (Table 2). This finding supports the view that the rapid onset of spinal anaesthesia triggers a pronounced sympathetic block, while CSEA modulates the onset in a controlled fashion that better preserves circulatory stability.

Importantly, no patient in either group showed ischemic changes on ECG monitoring. This indicates that, despite the hemodynamic differences, both techniques were ultimately safe in this selected population of stable coronary artery disease patients. Continuous ECG surveillance did not reveal any ST segment shifts, arrhythmias or other ischemic markers.

Intraoperative Cardiac Events

Continuous ECG monitoring did not reveal any ST-segment depression, T-wave inversion or arrhythmias suggestive of myocardial ischemia in either group throughout surgery. No patient reported chest discomfort, dyspnea or shoulder-tip pain. Oxygen saturation remained stable, with no desaturation episodes noted (Table 2).

Table 2: Intraoperative Hemodynamic Events and Management

Adverse Events and Safety Outcomes

Minor adverse effects such as nausea and dizziness were observed but occurred at similar rates across groups and were easily managed with standard measures. No case of post-dural puncture headache, epidural catheter-related complication, infection, or neurological deficit was recorded. No patient required conversion to general anaesthesia.

The present study compared the hemodynamic responses of SA and CSEA in patients with stable coronary artery disease undergoing lower-limb surgery. The findings clearly demonstrate that CSEA provided superior cardiovascular stability, with lower rates of hypotension, smaller reductions in MAP and reduced vasopressor requirement. These observations hold particular clinical value because perioperative hypotension is strongly associated with myocardial injury, acute kidney insult and increased postoperative morbidity in patients with limited cardiac reserve.

The significantly higher incidence of hypotension in the SA group aligns with the expected physiologic effect of an abrupt sympathectomy following intrathecal local anaesthetic administration. Rapid vasodilation reduces systemic vascular resistance and venous return, leading to a decline in MAP that may compromise coronary perfusion pressure. Studies in cardiac and elderly populations have described similar patterns, reporting hypotension rates as high as 40 to 60 percent after SA in high-risk individuals [11,12]. CAD patients are particularly vulnerable to such fluctuations because their ability to autoregulate myocardial oxygen supply is impaired. Even moderate drops in blood pressure can reduce subendocardial perfusion, especially in the presence of multi-vessel disease or left ventricular dysfunction.

In contrast, the CSEA technique resulted in fewer hypotensive episodes and more gradual hemodynamic changes. This difference likely stems from the technique’s ability to titrate epidural doses after administering a small intrathecal fraction. By extending the block level slowly, CSEA avoids the sudden sympathetic blockade typical of SA. Earlier investigations comparing low-dose SA with CSEA have also reported that CSEA maintains better preload and afterload conditions in patients with compromised cardiac function [13,14]. The smoother MAP trends observed in our study reinforce these findings and highlight the advantage of incremental dosing when managing patients with fragile coronary circulation.

The reduced vasopressor requirement in the CSEA group further supports its favorable hemodynamic profile. Frequent vasopressor use is undesirable in CAD patients, as agents such as phenylephrine may increase afterload or provoke reflex bradycardia, while others like ephedrine can trigger tachycardia, increasing myocardial oxygen demand. Studies evaluating intraoperative vasopressor trends have suggested that minimizing pharmacological interventions contributes to better myocardial outcomes and improved recovery in cardiac patients [15,16]. In our cohort, the SA group required three times more vasopressors than the CSEA group, underscoring the clinical relevance of choosing a technique that provides more intrinsic hemodynamic stability.

Differences in block onset characteristics also contributed to the overall stability profile. The faster onset with SA is well documented and often desirable for shorter procedures. However, in patients with reduced autonomic reserve, such a rapid change in sympathetic tone can provoke exaggerated cardiovascular responses. The slower, titratable onset of CSEA is a key advantage for CAD patients, allowing the anaesthesiologist to monitor changes in blood pressure more closely and intervene early if necessary. Several studies in orthopaedic and urological surgery have emphasized that gradual neuraxial block establishment is beneficial in patients with cardiac disease or severe hypertension [17,18].

It is notable that no ischemic ECG changes occurred in either group in our study. This may reflect careful preoperative optimization, judicious fluid management, and vigilant intraoperative monitoring. Previous research has shown that neuraxial anaesthesia can be safely administered to stable CAD patients when hemodynamic swings are minimized and monitoring is meticulous [19]. Nevertheless, the absence of ischemia does not diminish the clinical significance of the observed hemodynamic differences. Even transient hypotension without overt ECG changes may have subclinical consequences, as suggested by studies linking perioperative hypotension with troponin elevations and silent myocardial injury [20].

The overall findings of this study are in line with accumulating evidence favoring CSEA in high-risk cardiac populations. Its controlled dosing, greater flexibility, and more predictable hemodynamic profile make it an appealing choice for CAD patients where maintaining stability is essential. While SA remains simple, reliable and widely practiced, caution may be warranted when using it in patients with limited cardiovascular tolerance. A tailored approach that considers both surgical requirements and cardiac risk may therefore guide optimal anaesthetic decision-making.

Future investigations with larger samples, multicentric data and long-term follow-up would help validate the advantages observed in this study. Incorporating perioperative biomarkers such as high-sensitivity troponin, NT-proBNP and lactate could provide additional insight into the myocardial impact of each technique. Evaluating postoperative outcomes such as pain scores, recovery trajectories and hospital stay durations may further clarify the holistic benefits of CSEA for this patient population.

In this study, combined spinal–epidural anaesthesia demonstrated superior hemodynamic stability compared with spinal anaesthesia alone in patients with stable coronary artery disease undergoing lower-limb surgery. The CSEA technique was associated with fewer episodes of hypotension, a smaller early fall in mean arterial pressure, and reduced need for vasopressor support. These findings suggest that CSEA offers a more controlled and predictable cardiovascular profile, which is especially valuable when managing patients with limited cardiac reserve. Although both techniques were ultimately safe and no intraoperative ischemic events occurred, the more gradual sympathetic block provided by CSEA appears to make it the preferable regional technique for high-risk cardiac populations. Further studies incorporating larger cohorts and postoperative cardiac biomarkers would help validate and extend these observations.

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