Background: Acute aortic dissection (AAD) is a life-threatening vascular emergency that requires
prompt diagnosis, rapid triage, and immediate treatment with world wide in-hospital overall mortality of more than 27.4% as reported by the International Registry of Acute Aortic Dissection (IRAD). WBC count and NLR have been proposed as prognostic markers of a inflammatory state imposing worse clinical outcomes in cardiovascular diseases. This study aims to determine the accuracy of admission white blood cell count (WBC) and neutrophil-lymphocyte ratio (NLR) in predicting in-hospital cardiovascular-related mortality among patients with Acute Aortic Dissection (AAD) admitted at Philippine Heart Center.
Method: This is a retrospective cohort study to determine the accuracy of WBC count and NLR as a predictor of in-hospital CV outcomes in patients with AAD admitted at the Philippine Heart Center from January 2006 to December 2015. This study includes adult patients, aged 19 years and above, who presents with AAD, which was confirmed by imaging studies. For each patient, admission WBC and differential count was recorded and NLR was calculated. To compare the difference between patients who survived and died, independent t test for continuous variables and the chi-square test for categorical variables were used. Univariate analysis was used to analyze the association between WBC Count, NLR and in-hospital CV-mortality. Receiver opertating characteristic analysis were performed to determine the cut-off value for WBC count and NLR that is predictive of the in-hospital CV-outcome. A p value <0.05 was considered statistically significant.
Results: The study included 107 patients with imaging-confirmed diagnosis of acute aortic dissection, 79 (73.8%) of which survived and 28 (26.2%) patients died. The deceased patients were relatively older (mean of 59±13 years) compared with survived patients. There were no significant differences in terms of gender distribution, smoking history, hypertension, diabetes mellitus, dyslipidemia, coronary artery disease, peripheral artery disease, cerebrovasculaular disease, chronic kidney disease, asthma, chronic obstructive pulmonary disease and their presenting symptoms. In both the survived and deceased group, chest pain was the most common presenting symptoms. Patients with AAD may likewise be asymptomatic and they are more commonly seen in the deceased group than the survived group (11% versus 3%), though, the difference were not statistically significant (p=0.652). On admission, baseline diastolic blood pressure of the deceased patients were significantly lower than the survived patients (78
mmHg versus 70 mmHg, p=0.031), while the systolic blood pressure, heart rate, BMI did not differ between the 2 groups. Of the laboratory parameters, WBC count, neutrophil count, NLR, BUN, LDL and total cholesterol were slightly higher in deceased patients but the difference were not statistically significant (p >0.05). An ROC curve analysis was done and established the cut-off value was 5.55 for NLR and 14.03x109/L for WBC count. A univariate Cox regression analysis was performed and concluded that the odds of in-hospital cardiovascular-related mortality are 2.46 times higher in patients with elevated WBC count (≥ 14.03 x109/L). This result might be clinically relevant but not statistically significant (p >0.05).
Conclusion: With the gathered data in this study, admission WBC count is more accurate than
neutrophil-lymphocyte ratio in predicting in-hospital cardiovascular-related mortality for patients with AAD. It demonstrated a sensitivity of 62.50% and specificity of 59.60%. The odds of in-hospital cardiovascular-related mortality are 2.46 times higher in patients with elevated WBC count of ≥14.03x109/L, clinically relevant but not statistically significant (p >0.05). No significant association was found between admission NLR and in-hospital cardiovascular-related mortality. Relatively younger mean age and lower mean diastolic blood pressure of patients with acute aortic dissection associated with in-hospital mortality were found in this study compared with the current international established data.