2.1 General Data
A total of 102 IA patients undergoing microsurgical clipping from January 2017 to January 2019 in our hospital were selected as the objects, including 49 males and 53 females aged 33–72 years old, with an average of (56.54 ± 5.62) years old. All patients underwent aneurysm clipping within 72 h after IA rupture, including 21 cases within 24 h, 54 cases at 24–48 h, and 27 cases at 48–72 h. According to the postoperative treatment effect, the patients were divided into good prognosis group (n = 87) and poor prognosis group (n = 15).
Inclusion criteria were as follows: (1) patients diagnosed with IA by digital subtract angiography (DSA), CT angiography (CTA) or/and magnetic resonance angiography (MRA); (2) those in preoperative Hunt–Hess grade I–IV. The Hunt–Hess grading system, which describes the severity of subarachnoid hemorrhage due to intracerebral aneurysm rupture, is utilized to predict survival in clinical practice. Grade I: Asymptomatic or mild headache and neck stiffness; grade II: moderate to severe headache and neck stiffness, without neurologic deficit except for cranial nerve palsy; grade III: drowsy, with mild neurologic deficit; grade IV: stuporous, moderate to severe hemiparesis, with the possibility of early decerebrate rigidity and vegetative disturbances; grade V: deep coma, decerebrate rigidity and moribund; (3) those undergoing microsurgical clipping in our hospital; (4) those with complete medical records.
Exclusion criteria were as follows: (1) patients aged > 75 years old; (2) those with red blood cell, infectious, mental or other neurological diseases; (3) those with severe insufficiency of the heart, lung, liver, kidney or spleen. Seven cases were excluded, including one patient older than 75 years, three patients suffering from red blood cell, infectious, mental or other neurological diseases, and another three patients suffering from severe insufficiency of the heart, lung, liver, kidney or spleen.
This study was approved by the Ethics Committee of our hospital, and the patients and their families signed the informed consent.
2.2 Surgical Methods
All patients with IA underwent early surgery, namely microsurgical clipping within 72 h after aneurysm hemorrhage. The location of aneurysm was determined by CTA combined with DSA, the appropriate approach was selected, and the patient received general anesthesia with tracheal intubation in a supine position. If the patient had intracranial hypertension, mannitol was intravenously infused additionally. The lateral fissure cistern and the carotid cistern were dissected and separated under a microscope. The optic chiasm cistern was opened, and the cerebrospinal fluid was slowly released to fully expose the parent artery. Then, the aneurysmal neck was separated and clipped using appropriate clipping forceps, followed by wet dressing using papaverine cotton pads. During operation, the patient's blood pressure, blood gas and electrocardiogram were monitored.
2.3 Collection of Clinical Data
The general data of all patients were collected through the electronic medical record system, including age, gender, body mass index (BMI), preoperative Hunt–Hess grade (I, II, III and IV), history of hypertension, preoperative intracranial hematoma volume, aneurysm size, timing of surgery, length of hospital stay, postoperative complications (cerebral vasospasm, aneurysm rupture, cerebral edema, cerebral infarction, intracranial infection, and severe pulmonary infection), and the National Institute of Health Stroke Scale (NIHSS) score upon admission to hospital.
2.4 Assessment of Surgical Treatment Outcomes
The short-term prognosis of patients was assessed using the Glasgow Outcome Scale (GOS) score at discharge , as follows: 5 points (good recovery): the patient returned to normal life at discharge; 4 points (mild disability): the patient was disabled at discharge but could live independently; 3 points (severe disability): the patient was awake and disabled at discharge, and could act as instructed but needed daily care; 2 points (vegetative state): the patient could not interact with the outside world at discharge, and only had the least response; 1 point: death. 4–5 points indicate a good prognosis, while 1–3 points indicate a poor prognosis.
The postoperative clipping status (complete clipping, most clipping, and partial clipping) was recorded.
2.5 Statistical Analysis
SPSS 19.0 software was used for one-way analysis of variance of data. The t test and χ2 test were performed to compare the differences between two groups. The factors affecting the prognosis of IA patients were explored through multivariable logistic regression analysis and the variables with statistically significant differences were assigned values. The nomogram prediction model was established using R software (R3.3.2) and rms software package. The discrimination of the model was evaluated using receiver operating characteristic (ROC) curves, and the area under the curve was calculated. Concordance index (C-index) ranges from 0.5 to 1, and the value closer to 1 indicates that the prediction result is closer to the truth. Bootstrap method was used for internal validation. The actual C-index was compared with the internally validated C-index, and the closer the difference is to 0, the better the conformance of the model. Besides, 80 patients undergoing microsurgical clipping from February 2019 to August 2019 in our hospital were selected for external validation, and C-index was calculated to assess the accuracy of the model. The inclusion and exclusion criteria were the same as those in this study. P < 0.05 suggested statistically significant difference.