European Journal of Cardiovascular Medicine

Non-cardiac surgery is undertaken in large numbers worldwide, and perioperative cardiovascular complications continue to account for a substantial proportion of preventable morbidity and early postoperative mortality. Even when surgery proceeds without technical complications, the perioperative period is marked by sympathetic activation, systemic inflammation, anemia, pain, fluid shifts, and interruption or resumption of chronic medications, all of which can destabilize arterial pressure and impose stress on the myocardium. Importantly, many postoperative cardiac events are clinically silent and are detected only through systematic surveillance. The VISION study demonstrated a strong association between postoperative cardiac troponin elevation and 30-day mortality following non-cardiac surgery [1]. Subsequent studies refined this observation into the concept of myocardial injury after non-cardiac surgery (MINS), showing that even modest ischemic troponin elevations carry meaningful prognostic significance [2,3]. Contemporary reviews and pooled analyses have consistently reaffirmed the clinical relevance of perioperative myocardial injury across diverse surgical populations and health-care settings [4,5].

Among potentially modifiable perioperative factors, disturbances in blood pressure (BP) are frequent and clinically actionable. A large observational analysis proposed empirical thresholds for intraoperative hypotension based on their association with adverse postoperative outcomes [6]. In other non-cardiac surgical cohorts, intraoperative hypotension has been linked to both biochemical evidence and clinical manifestations of myocardial injury [7]. Analyses derived from randomized trial datasets have further examined the relationship between perioperative hypotension and myocardial injury [8], and similar associations have been reported in cohorts stratified according to pre-existing hypertension [9]. Collectively, these findings support the concept that deviations from optimal perfusion pressure whether due to hypotension or excessive afterload can precipitate myocardial oxygen supply–demand mismatch in susceptible patients.

Beyond isolated episodes of hypo- or hypertension, BP variability reflects the overall stability of perfusion and autonomic control. A systematic review reported that higher intraoperative BP variability is associated with adverse postoperative outcomes in non‑cardiac surgery [10]. Similarly, a prospective cohort study found that greater intraoperative BP variability predicted postoperative mortality after risk adjustment [11]. Importantly, postoperative BP derangements continue after transfer to the ward, where monitoring is intermittent and clinical responses can be delayed. Postoperative hypotension has been linked to myocardial injury after non‑cardiac surgery [12], while large cohorts also show that MACE remains clinically relevant even with contemporary\perioperative pathways [13]. Targeting\higher intraoperative blood pressure targets\alone has not consistently reduced adverse\cardiovascular events, suggesting that broader BP\stability across the perioperative continuum could be a\meaningful goal [14]\
Objectives: This retrospective cohort study aimed (i) to quantify postoperative BP variability during the first 48 hours after non‑cardiac surgery and (ii) to determine its association with in‑hospital MACE among adults treated at a tertiary care teaching hospital in India.

Study design and setting: This retrospective cohort study was performed at Government Medical College (GMC), Ananthapuramu, Andhra Pradesh, India. Medical records for surgeries conducted between March 2024 and May 2024 were reviewed.

Participants: Adults (≥18 years) who underwent non-cardiac surgery under general or regional anesthesia and remained hospitalized for at least 48 hours postoperatively were eligible. Exclusion criteria were: cardiac surgery, perioperative cardiac catheterization or intervention, pre-existing atrial fibrillation or chronic heart failure decompensation documented at baseline, incomplete BP documentation during the first 48 hours, or transfer to another facility before outcome ascertainment.

Data sources and variable definitions: Baseline demographics (age, sex, body mass index), comorbidities (hypertension, diabetes mellitus, coronary artery disease), smoking history, type of anesthesia, and surgical risk category (low/intermediate/high) were abstracted from case files and anesthesia records. Surgical risk categorization followed routine institutional documentation aligned with standard perioperative risk stratification practice.

Exposure assessment (postoperative BP variability):

Postoperative systolic BP (SBP) and diastolic BP (DBP) values recorded in nursing charts during the first 48 postoperative hours were extracted. For each patient, mean BP, SD, and coefficient of variation (CV = SD/mean × 100) were calculated for SBP and DBP. High postoperative BP variability was defined using the cohort median SD of SBP (12 mmHg), classifying patients into low variability (SD <12 mmHg) and high variability (SD ≥12 mmHg). In addition, episodes of marked hypertension (SBP >160 mmHg) and hypotension (SBP <90 mmHg) were recorded because extreme values and their duration have been associated with perioperative myocardial injury in prior work [6-9,12].

Outcome assessment:

The primary outcome was in-hospital major adverse cardiac events (MACE), defined as a composite of myocardial injury, new-onset arrhythmia, acute heart failure, and cardiac death. Myocardial injury was identified by postoperative troponin elevation above the local laboratory 99th percentile with a clinical adjudication consistent with ischemic injury, aligned with established perioperative constructs [1-4], or by clinician-documented myocardial infarction/myocardial injury in the discharge summary. New-onset arrhythmia and acute heart failure were captured when newly diagnosed and treated during admission (electrocardiographic documentation and/or cardiology notes). Cardiac death was defined as death attributed to a primary cardiac cause during hospitalization.

Statistical analysis:

Continuous variables are presented as mean ± SD and categorical variables as n (%). Group comparisons were performed using Student’s t-test (or Mann–Whitney U test when distributions were non-normal) and χ² or Fisher’s exact test for categorical data. Unadjusted associations between high BP variability and MACE were reported as odds ratios (OR) with 95% confidence intervals. A multivariable logistic regression model adjusted for age, baseline hypertension, diabetes mellitus, and surgical risk category was fitted to estimate the adjusted association. Analyses were performed using standard statistical software, and a two‑sided p value <0.05 was considered statistically significant.

Ethical considerations: Institutional ethics approval was obtained from GMC Ananthapuramu. The study was record-based with de-identified data extraction; therefore, individual informed consent was waived.

A total of 80 adults undergoing non-cardiac surgery with complete postoperative documentation for the first 48 hours were included in the analysis. The mean age of the cohort was 57.4 ± 10.2 years, and men constituted 52 patients (65.0%). Pre-existing hypertension was documented in 44 individuals (55.0%), diabetes mellitus in 28 (35.0%), and coronary artery disease in 16 (20.0%). Most surgical procedures were classified as intermediate-risk operations (50 patients, 62.5%) (Table 1).

Table 1. Baseline demographic and clinical characteristics of study participants (n = 80)

During the initial 48 postoperative hours, the mean systolic blood pressure (SBP) and diastolic blood pressure (DBP) were 134.6 ± 14.8 mmHg and 82.3 ± 9.6 mmHg, respectively. Considerable inter-individual variability in SBP was observed, with a mean patient-level SD of 14.5 ± 5.8 mmHg and a coefficient of variation of 10.8 ± 3.6%. Episodes of marked postoperative hypertension (SBP > 160 mmHg) occurred in 26 patients (32.5%), whereas hypotensive episodes (SBP < 90 mmHg) were documented in 14 patients (17.5%) (Table 2).

Table 2. Postoperative blood pressure variability during first 48 hours (n = 80)

Figure 1:Postoperative Blood Pressure Variability (First 48 Hours, n= 80)

Figure 2: Postoperative SBP Extremes (First 48 Hours, n=80)

Using the cohort median SD of SBP (12 mmHg) as the prespecified threshold, 38 patients (47.5%) were categorized as having low BP variability and 42 patients (52.5%) as having high BP variability (Table 3).

Table 3. Distribution of patients according to postoperative BP variability (n = 80)

Note: *Cut-off based on cohort median systolic BP standard deviation.

Patients in the high-variability group demonstrated substantially greater SBP fluctuation compared with those in the low-variability group (mean SD of SBP 18.6 ± 4.2 mmHg vs 9.8 ± 2.6 mmHg).

Overall, 18 patients (22.5%) experienced at least one in-hospital major adverse cardiac event (MACE). Myocardial injury was the most frequent component, occurring in 10 patients (12.5%), followed by new-onset arrhythmia in 6 (7.5%), acute heart failure in 4 (5.0%), and cardiac death in 2 patients (2.5%). Multiple events were observed in some individuals (Table 4). The incidence of MACE was significantly higher in the high BP variability group compared with the low-variability group (33.3% vs 10.5%), corresponding to an unadjusted odds ratio of 4.25 (95% CI: 1.26–14.38). After adjustment for age, hypertension, diabetes mellitus, and surgical risk category, high BP variability remained an independent predictor of MACE, with an adjusted odds ratio of approximately 3.1.

T

Table 4. Major adverse cardiac events (MACE) and association with BP variability (n = 80)

Note: Patients could experience more than one event; therefore, component event counts can exceed the number with any MACE.

In this retrospective cohort of adults undergoing non-cardiac surgery, more than half of the patients demonstrated high postoperative systolic blood pressure (BP) variability during the first 48 hours, and nearly one quarter experienced at least one in-hospital major adverse cardiac event (MACE). The principal finding was a strong association between high BP variability and adverse cardiac outcomes, with a threefold higher MACE rate compared with patients exhibiting more stable BP profiles. Importantly, this relationship remained significant after adjustment for age, baseline hypertension, diabetes mellitus, and surgical risk category, suggesting that BP variability conveys prognostic information beyond traditional risk factors.

The pattern of cardiac events observed in this cohort is consistent with contemporary perioperative literature, in which myocardial injury represents the predominant postoperative cardiac complication. Investigators from the VISION study and subsequent analyses have shown that postoperative troponin elevation—often occurring in the absence of ischemic symptoms—is independently associated with short-term mortality following non-cardiac surgery [1–3]. Systematic reviews and meta-analyses have further confirmed that myocardial injury after non-cardiac surgery is both common and clinically consequential across diverse health-care systems [4,5]. In the present study, myocardial injury accounted for more than half of all MACE events, reinforcing the importance of systematic surveillance for clinically silent perioperative myocardial injury.

From a pathophysiological perspective, instability in BP can directly perturb myocardial oxygen supply–demand balance. Episodes of hypotension may compromise coronary perfusion pressure, whereas hypertension increases afterload and myocardial work, thereby elevating oxygen demand. Both mechanisms can precipitate ischemic injury in patients with limited cardiovascular reserve. Large observational studies have linked lower mean arterial pressures with adverse postoperative outcomes and have proposed empiric thresholds of hypotension associated with harm [6]. Associations between intraoperative hypotension and biochemical or clinical evidence of myocardial injury have been demonstrated in observational cohorts [7] as well as in analyses derived from randomized trial datasets [8]. More recent retrospective studies suggest that susceptibility to BP deviations varies according to chronic hypertension status, underscoring the need for individualized perfusion targets rather than uniform BP thresholds [9].

An important additional insight from this study is that BP variability itself—captured using routine postoperative ward measurements—appears to carry clinically meaningful information. Although the exposure window in this analysis was postoperative, the observed association aligns with intraoperative evidence. A systematic review reported that greater perioperative BP variability is associated with an increased risk of postoperative adverse outcomes [10], and a prospective cohort study identified BP variability as a predictor of postoperative mortality [11]. While postoperative hypotension alone has been linked to myocardial injury [12], the present findings extend this concept by suggesting that overall BP stability across the postoperative period, rather than isolated extreme values, may be a more informative marker of cardiovascular risk.

From a clinical standpoint, these results support structured postoperative BP surveillance with timely escalation of care for patients exhibiting unstable BP trajectories. This approach is particularly relevant in resource-variable settings where continuous hemodynamic monitoring is unavailable and ward-based BP recordings guide decisions regarding fluid therapy, analgesia, vasopressor use, and resumption of antihypertensive medications. In large postoperative cohorts, MACE remains a clinically meaningful and measurable endpoint [13]. At the same time, evidence from randomized controlled trials indicates that targeting higher intraoperative BP alone does not necessarily reduce cardiovascular complications [14], highlighting the need to integrate BP stability within a broader framework of perioperative risk management. Future prospective studies incorporating standardized troponin surveillance and protocolized BP management are warranted to determine whether reducing postoperative BP variability can translate into improved cardiac outcomes.

Limitations

This single-center retrospective analysis relied on charted BP readings and documentation of cardiac events. The timing and frequency of BP measurements varied across patients, and continuous hemodynamic monitoring was unavailable. Troponin testing followed routine clinical practice rather than a uniform surveillance protocol, increasing outcome detection bias. Residual confounding from unmeasured factors such as anemia, analgesia, fluid balance, and vasoactive therapy persists despite multivariable adjustment.

In adults undergoing non-cardiac surgery at a tertiary care teaching hospital, postoperative BP variability during the first 48 hours was common, with over half of patients classified as having high systolic variability. In-hospital MACE occurred in nearly one-quarter of patients, predominantly myocardial injury. High BP variability showed a strong association with postoperative cardiac complications, including a substantially higher MACE rate compared with the low-variability group, and it remained an independent predictor after adjustment for key covariates. These findings support surveillance of postoperative BP trends, early identification of unstable BP trajectories, and standardized protocols for timely correction of hypo- and hypertensive excursions to strengthen perioperative cardiac safety.

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