Comparison of the Relationship Between Inflammatory Markers and Contrast-Induced Nephropathy in Patients With Acute Coronary Syndrome After Coronary Angiography

Preinterventional pan-immune-inflammation value as a tool to predict postcontrast acute kidney injury among acute coronary syndrome patients implanted drug-eluting stents: a retrospective observational study

We evaluated the value of pan-immune-inflammation value (PIV) in predicting the risk for postcontrast acute kidney injury (PCAKI), an important complication following percutaneous coronary intervention (PCI) in acute coronary syndrome (ACS) patients. Medical records of 839 ACS patients underwent PCI between June 2019 and December 2022 were retrospectively analyzed. Patients were divided into two groups: PCAKI (-) and PCAKI (+). PCAKI was defined as a ≥ 0.5 mg/dL and/or a ≥ 25% increase in serum creatinine within 72 h after PCI. The PIV was computed as [neutrophils × platelets × monocytes]÷lymphocytes. The mean age was 60.7 ± 12.9 years. PCAKI was detected in 105 (12.51%) patients. PIV was higher in the PCAKI (+) group compared to PCAKI (-) group (median 1150, interquartile range [IQR] 663-2021 vs median 366, IQR 238-527, p < 0.001). Receiver operating characteristic curve analysis showed that the best cutoff of PIV for predicting PCAKI was 576 with 81% sensitivity and 80% specificity. PIV was superior to neutrophil-lymphocyte ratio and platelet-lymphocyte ratio for the prediction of PCAKI (area under curve:0.894, 0.849 and 0.817, respectively, p < 0.001 for all). A high PIV was independently correlated with PCAKI (≤576 vs. >576, odds ratio [OR] 12.484, 95%confidence interval [CI] 4.853-32.118, p < 0.001) together with older age (OR 1.058, p = 0.009), female gender (OR 4.374, p = 0.005), active smoking (OR 0.193, p = 0.012), left ventricular ejection fraction (OR 0.954, p = 0.021), creatinine (OR 10.120, p < 0.001), hemoglobin (OR 0.759, p = 0.019) and c-reactive protein (OR 1.121, p = 0.002). In conclusion, a high PIV seems to be an easily assessable tool that can be used in clinical practice for predicting the risk of PCAKI in ACS patients implanted drug-eluting stents.

Prognostic Role of Neutrophil to Lymphocyte Ratio in Contrast-Induced Nephropathy: A Systematic Review and Meta-analysis

This meta-analysis assessed the use of the neutrophil-to-lymphocyte ratio (NLR) as a means of early detection of contrast-induced nephropathy (CIN) following diagnostic or therapeutic procedures. We used Web of Science, PubMed, and Scopus to conduct a systematic search. There was no limitation regarding language or date of publication. We reported standardized mean difference (SMD) with a 95% confidence interval (CI). Due to high heterogeneity, a random-effects model was used, and the Newcastle–Ottawa scale was used for quality assessment. Thirty-one articles were included in the analysis. Patients in the CIN group had elevated levels of NLR compared with those in the non-CIN group (SMD = 0.78, 95% CI = 0.52–1.04, P < .001). Similar results were observed in either prospective (SMD = 1.03, 95% CI = 0.13–1.93, P = .02) or retrospective studies (SMD = 0.70, 95% CI = 0.45–0.96, P < .001). The pooled sensitivity of NLR was 74.02% (95% CI = 66.54%–81.02%), and the pooled specificity was 60.58% (95% CI = 53.94%–66.84%). NLR shows potential as a cost-effective biomarker for predicting CIN associated with contrast-involved treatments. This could help implement timely interventions to mitigate CIN and improve outcomes.

C-Reactive Protein/Albumin Ratio as a Novel Predictor of Contrast Induced Nephropathy in Patients With Stable Angina Pectoris

The relationship between C-reactive protein (CRP) to albumin ratio (CAR) and contrast-induced nephropathy (CIN) in patients with acute coronary syndrome has been reported. However, the relevance of CAR in patients with stable angina pectoris (SAP) has not been clarified. We hypothesized that CAR might predict the development of CIN in patients with SAP undergoing coronary angiography (CAG). Patients (n = 554) with SAP who underwent CAG were included in the study. CIN was defined as a ≥25% increase in serum creatinine compared with baseline value within 72 h of CAG. Participants were divided into two groups: CIN (n = 87) and non-CIN (n = 467). Age, CRP, CAR, mean corpuscular volume (MCV), urea, uric acid, contrast medium volume, the percent of percutaneous coronary intervention were significantly greater, whereas albumin and high-density lipoprotein were significantly lower in the CIN group than non-CIN group (p < .05, for all). Multivariate analysis showed that CAR was the only independent predictor for CIN (odds ratio = 7.065, 95% confidence interval (CI); 3.279-15.221, p < .001). Receiver operating characteristic ROC analysis showed that a CAR ≥ 0.1164 could predict CIN (sensitivity of 71% and specificity of 72%; area under curve = 0.736; 95% CI: 0.677-0.795, p < .001). CAR was significantly greater in patients who developed CIN and this independently predicted CIN.

Predictive value of SII and sd-LDL for contrast-induced acute kidney injury in STEMI patients undergoing percutaneous coronary intervention

Aim: To investigate the relationship between the incidence of contrast-induced acute kidney injury (CI-AKI) and the level of small dense low-density lipoprotein (sd-LDL) and systemic immune-inflammation index (SII) in patients with acute ST-segment elevation myocardial infarction (STEMI) undergoing emergency percutaneous coronary intervention (PCI), and to further compare the predictive values of SII, sd-LDL and their combination for CI-AKI. Methods: A total of 674 patients were assigned to a training and a validation cohort according to their chronological sequence. The baseline characteristics of the 450 patients in the training cohort were considered as candidate univariate predictors of CI-AKI. Multivariate logistic regression was then used to identify predictors of CI-AKI and develop a prediction model. The predictive values of SII, sd-LDL and their combination for CI-AKI were also evaluated. Results: Multivariate logistic regression analysis showed that age, left ventricular ejection fraction (LVEF), sd-LDL, uric acid, estimated glomerular filtration rate (eGFR) and SII were predictors of CI-AKI. The area under the curve (AUC) of the prediction model based on the above factors was 0.846 [95% confidence interval (CI) 0.808–0.884], and the Hosmer-Lemeshow test (P = 0.587, χ2 = 6.543) proved the goodness of fit of the model. The AUC combining SII with sd-LDL to predict CI-AKI was 0.785 (95% CI 0.735–0.836), with a sensitivity of 72.8% and a specificity of 79.8%, and was statistically significant when compared with SII and sd-LDL, respectively. The predictive efficiency of combining SII with sd-LDL and SII were evaluated by improved net reclassification improvement (NRI, 0.325, P < 0.001) and integrated discrimination improvement (IDI, 0.07, P < 0.001). Conclusions: Both SII and sd-LDL can be used as predictors of CI-AKI in STEMI patients undergoing emergency PCI, and their combination can provide more useful value for early assessment of CI-AKI.

Association of mean platelet volume/lymphocyte ratio with inflammation in non-dialysis patients with chronic kidney disease stages 1-4: A retrospective study

Objective

The mean platelet volume/ratio (MPVLR) is recognized as a novel marker of inflammation. We evaluated whether the MPVLR is associated with inflammation in non-dialysis patients with chronic kidney disease (CKD) stages 1-4.

Methods

A total of 402 non-dialysis patients with CKD stages 1-4 were included. The indicators of hematological, renal function (urea, serum creatinine [Scr], estimated glomerular filtration rate [eGFR], and urine albumin to creatinine ratio [ACR]) and the markers of inflammation (high-sensitivity C-reactive protein [hsCRP] and fibrinogen [FIB]) were recorded. The MPVLR values at different CKD stages were analyzed. Next, based on the absence (hsCRP level < 5 mg/L) and presence (hsCRP level > 5 mg/L) of inflammation, the patients were categorized, and the differences in indices between the two groups were observed. The patients were divided into two groups based on the median MPVLR value (6.39) at admission. The laboratory indices of patients with CKD were compared. Simultaneously, a correlation analysis was performed to identify the association between the MPVLR and each parameter. A binary logistic regression analysis was performed to test whether the MPVLR was associated independently with the presence of inflammation in non-dialysis patients with CKD. The receiver operating characteristic (ROC) curve was used to analyzed diagnostic performance of the MPVLR in evaluating the inflammation of non-dialysis patients with CKD stages 1-4.

Results

The MPVLR was higher in patients with CKD stages 3-4 than in those with CKD stages 1 and 2. Significant differences in urea, Scr, eGFR, ACR, lymphocyte (LYM), red blood cell (RBC), hemoglobin (HGB), RBC distribution width (RDW-CV), MPVLR, and FIB values were observed between the groups with and without inflammation. The patients with a higher MPVLR had higher urea, Scr, ACR, WBC, neutrophils (NEU), RDW-CV, platelet distribution width (PDW), mean platelet volume (MPV), and hsCRP values and lower eGFR, LYM, RBC, HGB, and platelet (PLT) values. The MPVLR showed a positive correlation with age, urea, Scr, WBC, NEU, RDW-CV, PDW, MPV, and hsCRP values and a negative correlation with the eGFR, LYM, RBC, HGB, and PLT values. A logistic analysis revealed that the MPVLR was associated independently with the presence of inflammation in non-dialysis patients with CKD, after adjustment for the confounding factors (odds ratio = 1.020; P = 0.024). Furthermore, MPVLR exhibited a modest diagnostic performance for the assessment of inflammation in non-dialysis patients with CKD stages 1-4, with an area under the curve (AUC) of 0.706, and the sensitivity, specificity being 46.2% and 83.2%, respectively.

Conclusions

The MPVLR was associated independently with the presence of inflammation in non-dialysis patients with CKD and may be useful for monitoring inflammation.

Mean platelet volume to lymphocyte ratio and platelet distribution width to lymphocyte ratio in Iraqi patients diagnosed with systemic lupus erythematosus

Introduction

The mean platelet volume to lymphocyte ratio (MPVLR) and platelet distribution width to lymphocyte ratio (PDWLR) have the potential to serve as markers of inflammation which may indicate disease activity. The mean platelet volume to lymphocyte ratio and PDWLR were assessed in patients with systemic lupus erythematosus (SLE) in this study.

Material and methods

Sixty-two patients with systemic lupus erythematosus and 79 controls who were age and gender matched were included. Their sociodemographic information, as well as disease activity scores based on the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI), disease duration, current medications, lymphocytes, platelets, platelet distribution width (PDW), and mean platelet volume (MPV), anti-nuclear antibody (ANA), anti-double stranded deoxyribonucleic acid (anti-dsDNA), and complement components (C3, C4) were recorded. The correlations of MPVLR and PDWLR with disease activity and some laboratory parameters were analyzed.

Results

Lupus patients had significantly higher median (interquartile range) values for MPVLR and PDWLR than controls (5.69 [1.16-23.67] vs. 4.40 [2.78-11.93], p = 0.009) and 10.51 (2.87-79.37) vs. 5.21 (2.88-14.66), p < 0.001] respectively. According to the ROC curve, > 7.53 was the best PDWLR cut-off value for predicting SLE with a sensitivity of 71%, a specificity of 87% and an accuracy of 82.6%, whereas the optimum MPVLR cut-off value was > 6.46 with a sensitivity of 45.2%, a specificity of 88.9% and an accuracy of 76.8%. In addition, MPVLR had a significant positive correlation with SLEDAI (r = 0.34, p = 0.008). However, there was no significant correlation between PDWLR and SLEDAI (r = 0.23, p = 0.067). Furthermore, PDWLR had a significant positive correlation with PDW (r = 0.482, p < 0.001), while MPVLR had a significant negative correlation with C3 level (r = -0.260, p = 0.042). Both PDWLR and MPVLR were positively correlated with nephritis (r = 0.388, p = 0.002; r = 0.246, p = 0.038, respectively).

Conclusions

The platelet distribution width to lymphocyte ratio can be considered as an assisting biomarker in the diagnosis of SLE with the other clinical and serological parameters. The mean platelet volume to lymphocyte ratio may be used in the evaluation of disease activity in SLE patients.

The utility of systemic immune-inflammation index for predicting contrast-induced nephropathy in patients with ST-segment elevation myocardial infarction undergoing primary percutaneous coronary intervention

OBJECTIVE

The systemic immune-inflammation index (SII), derived from counts of neutrophil, platelet and lymphocyte, have been developed to predict clinical outcomes in several cancers and cardiovascular diseases. The aim of this study was to evaluate the utility of SII to predict contrast-induced nephropathy (CIN) in patients with ST-segment elevation myocardial infarction (STEMI) who underwent primary percutaneous coronary intervention (PCI).

METHODS

A total of 632 patients with STEMI who underwent primary PCI were retrospectively included. The patients divided into two groups based on the presence or absence of CIN. Baseline demographic, laboratory and clinic characteristics were evaluated between the two groups. Logistic regression analysis was used to identify independent predictors of CIN.

RESULTS

The receiver-operating characteristic (ROC) curve analysis demonstrated that the optimal cut-off value of SII for predicting CIN was 1282 with a sensitivity 76.1% and specificity 86.7% (AUC: 0.834; 95% CI 0.803-0.863; p<0.001). Multivariate analysis performed in two models (SII; as separate continuous and categorical variables) showed age, estimated glomerular filtration rate (eGFR), diabetes, left ventricular ejection fraction (LVEF), Killip class ≥2, use of intravenous diuretic, Troponin I, and SII as independent predictors of CIN in Model 1. In Model 2, age, eGFR, diabetes, LVEF, Killip class ≥2, use of intravenous diuretic, Troponin I, and a value of SII >1282 (p<0.001, OR 6.205, 95% CI 2.301-12.552) remained as independent predictors of CIN.

CONCLUSION

SII may be a useful and reliable indicator to predict the development of CIN in patients with STEMI undergoing primary PCI than NLR and PLR.

Hypertension as a Risk Factor for Contrast-Associated Acute Kidney Injury: A Meta-Analysis Including 2,830,338 Patients

OBJECTIVE

Previous studies have shown that the relationship between hypertension (HT) and contrast-associated acute kidney injury (CA-AKI) is not clear. We apply a systematic review and meta-analysis to assess the association between HT and CA-AKI.

METHODS

We searched for articles on the study of risk factors for CA-AKI in the Embase, Medline, and Cochrane Database of Systematic Reviews (by March 25, 2021). Two authors independently performed quality assessment and extracted data such as the studies' clinical setting, the definition of CA-AKI, and the number of patients. The CA-AKI was defined as a serum creatinine (SCr) increase ≥25% or ≥0.5 mg/dL from baseline within 72 h. We used fixed or random models to pool adjusted OR (aOR) by STATA.

RESULTS

A total of 45 studies (2,830,338 patients) were identified, and the average incidence of CA-AKI was 6.48%. There was an increased risk of CA-AKI associated with HT (aOR: 1.378, 95% CI: 1.211-1.567, I2 = 67.9%). In CA-AKI with a SCr increase ≥50% or ≥0.3 mg/dL from baseline within 72 h, an increased risk of CA-AKI was associated with HT (aOR: 1.414, 95% CI: 1.152-1.736, I2 = 0%). In CA-AKI with a Scr increase ≥50% or ≥0.3 mg/dL from baseline within 7 days, HT increases the risk of CA-AKI (aOR: 1.317, 95% CI: 1.049-1.654, I2 = 51.5%).

CONCLUSION

Our meta-analysis confirmed that HT is an independent risk factor for CA-AKI and can be used to identify risk stratification. Physicians should pay more attention toward prevention and treatment of patients with HT in clinical practice.

Contrast-induced nephropathy in non-cardiac vascular procedures, a narrative review: Part 1

Contrast-induced nephropathy (CIN) is an important complication of iodinated contrast medium (CM) administration, which is associated with both short- and long-term adverse outcomes (e.g., cardiorenal events, longer hospital stay, and mortality). CIN has been mainly studied in relation to cardiac procedures, but it can also occur following non-cardiac vascular interventions. This is Part 1 of a narrative review summarizing the available literature on CIN after non-cardiac vascular diagnostic or therapeutic procedures for aortic aneurysm and carotid stenosis. We discuss the definition, pathophysiology, incidence, risk factors, biomarkers, and consequences of CIN in these settings, as well as preventive strategies and alternatives to limit iodinated CM use. Physicians and vascular surgeons should be aware of CM-related adverse events and the potential strategies to avoid them. Clearly, more research in this important field is required.

Association between Prognostic Nutritional Index and Contrast-Associated Acute Kidney Injury in Patients Complicated with Chronic Kidney Disease and Coronary Artery Disease

Background

Contrast-associated acute kidney injury (CA-AKI) is a major adverse effect of coronary angiography (CAG). Patients with chronic kidney disease (CKD) and coronary artery disease (CAD) are at high risk of CA-AKI. This study aimed to investigate the association between prognostic nutritional index (PNI) and CA-AKI in this high-risk population.

Methods

This study enrolled a total of 4,391 patients. CA-AKI was defined as a serum creatinine increase ≥0.3 mg/dL or 50% from baseline within the first 48 hours following CAG. The PNI was calculated upon hospital admission: serum albumin (g/L) + 5 × total lymphocyte count (10⁹/L). PNI was analysed from the high level to low level as a continuous variable and categorical variable which was divided into four groups by quartile. Restricted cubic splines and logistic regression were applied.

Results

Overall, 13.09% (575/4391) of patients developed CA-AKI. PNI score was significantly lower in patients with CA-AKI than that in patients without CA-AKI (P < 0.01). The relationship between PNI score and CA-AKI was linear. A logistic regression model revealed that decreased PNI score was associated with increased risk of CA-AKI [per 1-point decrement; adjusted OR = 1.08, 95% CI, 1.05–1.09; compared with Quartile 1 (PNI ≥ 46.30), Quartile 4 (PNI < 37.90), adjusted OR = 1.88, 95% CI: 1.41–2.51; and Quartile 3 (37.90 ≤ PNI < 42.15), adjusted OR = 1.37, 95% CI: 1.02–1.84].

Conclusion

Our study indicated a negative linear relationship between PNI score and CA-AKI in patients undergoing CAG complicated with CKD and CAD. It suggested that malnutrition is associated with increased risk of CA-AKI in this population.

Acute Urticaria in Inpatients Undergoing Non-emergent Coronary Angiography With Corticosteroid Prophylaxis: A Retrospective Study

Background and Aims: Acute urticaria (AU) is the most frequently reported immediate hypersensitivity reaction in skin by administration of iodinated contrast media (ICM). We aimed to establish the pattern and identify the risk factors of AU among inpatients undergoing non-emergent coronary angiography (CAG) with prophylactic corticosteroids in China.

Methods: Medical records of 19,326 adult inpatients undergoing non-emergent CAG with prophylactic methylprednisolone in 2013–2019 were retrospectively investigated. AU was identified within 1 h post-ICM administration, and diffuse involvement was defined when wheals occur in two or more body parts, including the back, abdomen, chest, and extremities. Age- and sex-matched inpatients (1:4) without AU were randomly selected for assessment of risk factors.

Results: Approximately 0.8% of CAG inpatients had AU, including 101 diffuse and 64 limited form. The diffuse AU was more common in settings of non-diagnostic CAG, iohexol used, average ICM injection≥3 ml/min, recurrent CAG, and past history of immediate hypersensitivity to ICM. Inpatients with preexisting allergies, decreased evaluated glomerular filtration rate, and increased high sensitivity C reactive protein or neutrophil-to-lymphocyte ratio prior to CAG had a higher probability of AU (odds ratio >1, P < 0.05 for all variables). All AU inpatients complained of pruritus, and mild itching predominated. AU dissipated in several days under treatment of ebastine or levocetirizine 10 mg/daily, but ebastine showed superiority.

Conclusions: ICM-induced AU is not uncommon in non-emergent CAG inpatients with prophylactic methylprednisolone. Preexisting allergies, renal dysfunction, and mild inflammation are high-risk factors, and antihistamine monotherapy is a favorable candidate for ICM-related AU.

Nutritional status and risk of contrast-associated acute kidney injury in elderly patients undergoing percutaneous coronary intervention

Background

This study aimed to investigate the connection between malnutrition evaluated by the Controlling Nutritional Status (CONUT) score and the risk of contrast-associated acute kidney injury (CA-AKI) in elderly patients who underwent percutaneous coronary intervention (PCI).

Methods

A total of 1308 patients aged over 75 years undergoing PCI was included. Based on the CONUT score, patients were assigned to normal (0–1), mild malnutrition (2–4), moderate-severe malnutrition group (≥ 5). The primary outcome was CA-AKI (an absolute increase in ≥ 0.3 mg/dL or ≥ 50% relative serum creatinine increase 48 h after contrast medium exposure).

Results

Overall, the incidence of CA-AKI in normal, mild, moderate-severe malnutrition group was 10.8%, 11.0%, and 27.2%, respectively (p < 0.01). Compared with moderate-severe malnutrition group, the normal group and the mild malnutrition group showed significant lower risk of CA-AKI in models adjusting for risk factors for CA-AKI and variables in univariate analysis (odds ratio [OR] = 0.48, 95% confidence interval [CI]: 0.26–0.89, p = 0.02; OR = 0.46, 95%CI: 0.26–0.82, p = 0.009, respectively). Furthermore, the relationship were consistent across the subgroups classified by risk factors for CA-AKI except anemia. The risk of CA-AKI related with CONUT score was stronger in patients with anemia. (overall interaction p by CONUT score = 0.012).

Conclusion

Moderate-severe malnutrition is associated with higher risk of CA-AKI in elderly patients undergoing PCI.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10157-021-02061-4.

Inflammatory Indicators and Hematological Indices in Contrast-Induced Nephropathy Among Patients Receiving Coronary Intervention: A Systematic Review and Meta-Analysis

Strong inflammatory indicators such as C-reactive protein (CRP), high-sensitivity CRP (hsCRP), and hematological indices, including platelet to lymphocyte ratio (PLR), neutrophil to lymphocyte ratio (NLR), hematocrit (HCT), and red blood cell distribution width (RDW), may be related with contrast-induced nephropathy (CIN). Our meta-analysis aimed at exploring the relationship between these indicators and CIN incidence among patients undergoing coronary intervention. Clinical studies were retrieved from the electronic databases of PubMed, EMBASE, Google Scholar, Clinical Trials, and Science Direct from their inception to June 3, 2020. Meta-analysis was performed on pooled eligible studies. Finally, 26 studies involving 29 454 patients were included. Pooled analysis revealed that patients with higher CRP (odds ratio [OR] = 1.06, 95% CI: 1.01-1.12, P = .02), hsCRP (OR = 1.03, 95% CI: 1.01-1.06, P = .004), NLR (OR = 1.11, 95% CI: 1.01-1.20, P = .02), RDW (OR = 1.35, 95% CI: 1.19-1.53, P < .001), and lower HCT (OR = 0.94, 95% CI: 0.92-0.97, P = .003) all exhibited significantly higher CIN rates, but there was no significant association between PLR and CIN risk (OR = 1.12, 95% CI: 0.99-1.26, P = .07). Pre-angiography CRP/hsCRP and some hematological indices are associated with CIN.

Impact of low serum hemoglobin on development of contrast-induced nephropathy (CIN) in patients with hepatocellular carcinoma (HCC) following transarterial chemoembolisation (TACE)

OBJECTIVES

To assess the association between low hemoglobin (Hb) level and development of contrast-induced nephropathy (CIN) for hepatocellular carcinoma (HCC) patients after transarterial chemoembolization (TACE).

METHODS

A retrospective analysis was performed on 284 patients undergoing 503 consecutive sessions of TACE. Propensity score matching (PSM) analysis was used to reduce the influence of the difference in variables in normal and low hemoglobin groups. Risk factors of CIN were assessed by univariate and multivariate logistic regression analysis. The relation between Hb level and CIN development was analyzed by receiver operating characteristic (ROC) curve.

RESULTS

CIN developed in 5.6% patients after TACE. Multivariate logistic regression analysis showed that hypertension, Hb and serum creatinine (Scr) were independent risk factors for the development of post-TACE CIN. Grouped by normal or low Hb, the incidence of CIN was 14.6% (16/110) in the low Hb group and 3.4% (4/116) in the normal Hb group after PSM. Multivariate logistic regression analysis revealed that Hb, lymphocyte count, and neutrophil to lymphocyte ratio (NLR) were independent risk factors for the development of post-TACE CIN. The optimal cut-off point at which the Hb concentration resulted in a high probability of developing CIN was 105.5 g/L in males.

CONCLUSIONS

Low Hb is an independent risk factor for post-TACE CIN. Therefore, HCC patients with low Hb levels should be closely monitored before and during TACE.

Association between α1-antitrypsin and acute coronary syndrome

α1-antitrypsin (AAT) is a protein released as part of the anti-inflammatory response. It regulates the activity of serine proteinases and has a crucial role in the pathogenesis of acute coronary syndrome (ACS). The present study aimed to examine its role in patients with ACS. The plasma samples of 117 patients were collected at the Cardiology Department of the Affiliated Hospital of Youjiang Medical University (Baise, China). These included 46 cases of ACS (who met the diagnostic criteria for ACS and had ≥50% luminal stenosis of any coronary vessel), 35 cases of stable angina (SA; with ≥50% luminal stenosis of any coronary vessel but in a stable condition) and 36 normal healthy controls (subjects with no luminal stenosis in their coronary arteries). Plasma AAT protein concentrations were measured by ELISA and clinical data were collected. The plasma levels of AAT protein in patients with ACS were lower than those in controls and cases of SA (P<0.05), and the levels tended to decrease with the number of coronary artery lesions involved. There were no significant associations of the expression of plasma AAT protein and the number of diseased vessels in patients or the degree of stenosis. There was no correlation between the plasma protein levels of AAT and Gensini scores of patients with ACS. In conclusion, the plasma AAT protein levels in patients with ACS may contribute to the occurrence and development of coronary artery disease.