Analysis of Risk Factors of Postoperative Lower Extremity Deep Venous Thrombosis in Patients With Cervical Cancer

Abstract

Deep venous thrombosis (DVT) has a significant negative impact on surgical and tumor patient's safety and quality of life. There was no specific report on the incidence and risk factors of postoperative lower extremity DVT in cervical cancer patients. Analysis of the risk factors of postoperative DVT in patients with cervical cancer is of great clinical significance for prevention and treatment. We retrospectively analyzed 309 cervical cancer patients treated by the Hubei Cervical Cancer Prevention Center and used a logistic regression model to test the risk variables of postoperative lower extremity deep venous thrombosis in cervical cancer patients. By univariate analyses, the results of the study showed that the incidence of postoperative DVT was significantly increased in cervical cancer patients complicated with old age, obesity, high preoperative plasma D-dimer level, increased preoperative triglyceride level, chronic diseases (hypertension, diabetes, and cardiovascular disease), open surgery, long operation time, intraoperative blood transfusion, advanced tumor stage, and preoperative chemotherapy/radiotherapy. Advanced age, obesity, elevated preoperative D-dimer level, high preoperative triglyceride level, and open surgery were independent risk factors for postoperative lower extremity DVT in patients with cervical cancer by multivariate regression analyses (all P < .05). In gynecologic patients with cervical cancer, there is a high incidence of postoperative lower extremity DVT. Clinicians should develop systematic and comprehensive prevention and treatment measures for the risk factors to lower this morbidity and improve patient prognosis.

Introduction

Deep venous thrombosis (DVT) is an impaired venous reflux disorder caused by abnormal clotting of blood in the deep veins that has a significant negative impact on a patient's safety and quality of life.^1–3 Hence, it is of particular importance to evaluate the risk factors of DVT before thrombosis and take effective clinical measures to prevent, find, and treat DVT in time.

Malignant tumors are recognized as high-risk factors for DVT.^4,5 Studies have found that due to the advanced age, pelvic mass compressing the vasculature, lengthy surgery, and the influence of chemotherapy, radiotherapy, and other factors, gynecological cancer patients have greatly increased risk of postoperative DVT.^6–10 Besides, the study also shows that gynecological malignant patients combined with lower extremity DVT may be characterized by difficult treatment, high recurrence rates, and poor prognosis. ¹¹ Therefore, early and comprehensively analyzing, generalizing, and summarizing the risk factors of lower limb DVT in gynecological cancer patients to make effective preventive measures, which is highly clinically significant in lowering the incidence of DVT and enhancing patient prognosis.

Cervical cancer is one of the most common gynecological malignancies. ¹² In recent years, due to the lack of disease awareness, insufficient vaccine prevention and disease screening, smoking, early sexual behavior, multiple sexual partners, and other factors, the incidence of cervical cancer has been increasing.^13,14 Currently, there are few comprehensive studies on the specific analysis of risk factors of postoperative DVT in cervical cancer patients. Hence, in this study, we collected the clinical data of relevant patients and analyzed the occurrence and risk factors, aiming to provide theoretical guidance for the clinical targeted prevention, in order to reduce the occurrence of DVT.

Materials and Methods

Patients

Retrospective clinical data collection was done on patients with cervical cancer who underwent surgical therapy at the Maternal and Child Health Hospital of Hubei Province between January 2020 and June 2023. Inclusion criteria: (1) patients clinically diagnosed with cervical cancer, (2) patients over 40 years old, (3) patients being prepared for surgical treatment, (4) patients with no previous history of thrombosis, (5) patients not receiving preoperative anticoagulation prophylaxis, (6) patients with complete clinical data, (7) all patients and their families were informed of and agreed to the study. Exclusion criteria: (1) patients with other gynecological malignant tumors and tumors of other organs and tissues, (2) patients with preoperative coagulation disorders or long-term oral medications that affect coagulation, (3) patients with past experiences of thromboembolism, and (4) patients who cannot communicate and cooperate well. Both the patient and their family members were aware and agreed to this study. The Health Research Ethics Committee of Hubei Maternal and Child Health Hospital approved the study.

Disease Diagnostic Criteria

The criteria for clinical staging of cervical cancer refer to FIGO 2018. ¹⁵ The diagnostic criteria for lower limb DVT refer to clinical guidelines. ² A bilateral deep vein ultrasound of the lower limbs was performed by an experienced sonographer. DVT can be diagnosed when color Doppler ultrasound (CDUS) shows the following: (1) there was a substantial echo in the vascular lumen and no collapse or partial collapse was observed after probe compression, (2) the presence of eccentric and central filling defects in the venous lumen. Bilateral lower limb compression ultrasound scans were performed on all patients within 3 days before surgery, on postoperative days third, seventh, and 30th. Patients with suspicious DVT symptoms such as leg distension, pain, and numbness received CDUS at any time. CT pulmonary angiography was performed at any time for patients with suspicious PE symptoms such as palpitation, chest tightness, dyspnea, etc. Due to the special and complex medical environment in China, patients cannot accept the fact that a thrombus has formed before surgery without being detected and prevented in time, as well as the increasing incidence of postoperative DVT in surgical patients in recent years, our hospital has formulated corresponding examination procedures since 2019. For hospitalized patients who need to undergo surgery, a bilateral lower extremity vein ultrasound examination is required at a specific period before and after surgery in order to detect and treat DVT early. Therefore, in this retrospective study, we can scan patients and have relatively complete examination data.

Data Collection

General clinical characteristics (age, body mass index [BMI], number of pregnancies and deliveries, and chronic complications), preoperative laboratory test data (plasma D-dimer, plasma fibrinogen, activated partial thromboplastin time (APTT), prothrombin time (PT), thrombin time (TT), hemoglobin, platelet counts, albumin, triglycerides, and total cholesterol), surgical treatments (surgical modality, surgical duration, intraoperative hemorrhage, and intraoperative transfusion), and tumor profile (tumor type, tumor stage, and the history of preoperative radiotherapy and chemotherapy) were recorded.

Statistical Analysis

All of the data in the study were statistically analyzed using SPSS 27.0 software. The measurement data that conforms to the chi-square normal distribution is represented as the mean and standard deviation, and the t-test of 2 independent samples is used for intergroup comparison. Comparative analysis between groups was done using the χ²-test, and count results were expressed as rate and composition ratio (%). Potential variables were first screened out using univariate analysis, and then the risk factors affecting cervical cancer complicating lower limb DVT were analyzed using a logistic regression model. P-value lower than .05 was considered statistically significant.

Results

Baseline of the Study

From January 2020 to June 2023, a total of 309 patients were diagnosed with cervical cancer in Hubei Provincial Maternal and Child Health Hospital. Ultimately, 282 patients were enrolled in this study based on the inclusion and exclusion criteria, and they were split into 2 groups based on whether they developed DVT within 1 month after surgery: the DVT group (70 cases) and the non-DVT group (212 cases). The experiment's flowchart is shown in Figure 1.

Figure 1.

The study flowchart. Note: DVT, deep venous thrombosis; PE, pulmonary embolism.

Among 282 cervical cancer patients who underwent surgical treatment, 70 cases of lower limb DVT occurred within 1 month after surgery, accounting for 24.8% (70/282). In the DVT group, there were 43 cases of calf DVT (including 31 cases of intermuscular vein, 7 cases of peroneal vein, and 5 cases of posterior tibial vein), 14 cases of femoral vein DVT, and 13 cases of popliteal vein DVT. Pulmonary embolism occurred in 14 patients with DVT.

Univariate and Multivariate Analysis

The clinical characteristics of the patients are shown in Table 1. Firstly, we consulted the basic information of these cervical cancer patients, such as age, height, weight, childbearing history, and history of previous disease, and collated and analyzed these data. It revealed that the number of pregnancies and deliveries were not obviously different between the DVT group and non-DVT group, but the mean age and BMI of patients in the non-DVT group were significantly lower than those in the DVT group, and the proportion of patients with hypertension, diabetes, and cardiovascular disease is also lower than that in the DVT group (P < .05). It indicated that age, BMI, hypertension, diabetes, heart disease and other underlying diseases may be the risk factors for postoperative lower extremity DVT in cervical cancer patients.

Table 1.

Clinical Characteristics of the Patients.

Factors	Non-DVT (n = 212)	DVT (n = 70)	Χ2/t	P
Age (years)	53.03 ± 6.42	57.48 ± 6.21	3.220	<.001
Number of pregnancies	3.78 ± 1.89	3.42 ± 1.62	0.934	.353
Number of deliveries	2.05 ± 1.04	2.15 ± 1.15	0.457	.649
BMI (kg/m2)	23.26 ± 2.78	24.89 ± 3.36	2.667	.009
Chronic diseases [n (%)]
Hypertension	27（12.74）	25（35.71）	8.486	.004
Diabetes	21（9.9）	17（24.29）	3.899	.048
Cardiovascular disease	8（3.77）	15（21.43）	8.832	.003
D-dimer (mg/mL)	0.38 ± 0.26	0.71 ± 0.46	4.872	＜.001
FIB (g/L)	3.12 ± 2.13	3.01 ± 0.50	0.286	.775
APTT (s)	29.76 ± 2.95	30.28 ± 4.15	0.758	.450
PT (s)	11.36 ± 0.85	11.23 ± 0.77	0.732	.466
TT (s)	14.78 ± 1.12	14.58 ± 0.93	0.896	.372
Hgb (g/L)	122.28 ± 12.29	123.91 ± 12.88	0.634	.527
Plt (×109/L)	242.65 ± 57.72	259.61 ± 70.55	1.329	.187
Albumin (g/L)	41.43 ± 3.82	41.09 ± 3.94	0.422	.673
TG (mmol/L)	1.27 ± 0.60	1.71 ± 0.77	3.289	＜.001
TC (mmol/L)	4.65 ± 0.97	5.03 ± 1.07	1.824	.070
Surgical method [n (%)]			6.004	.014
OS	100（47.17）	51（72.86）
LS	112（52.83）	19（27.14）
Surgical duration (min)	268.45 ± 58.62	301.42 ± 58.10	2.726	.007
Intraoperative bleeding (mL)	165.38 ± 127.96	219.10 ± 176.92	1.806	.074
Blood transfusion [n (%)]			6.033	.014
Yes	16（7.55）	18（25.71）
No	196（92.45）	52（74.29）
Tumor type [n (%)]			0.986	.321
SCC	176（83.02）	50（71.43）
NSCC	36（16.98）	20（28.57）
Tumor staging [n (%)]			4.871	.027
Stage Ⅰ and Ⅱ	193（91.04）	53（75.71）
Stage Ⅲ and Ⅳ	19（8.96）	17（24.29）
Chemotherapy/radiotherapy			3.986	.046
Yes	40（18.87）	25（35.71）
No	172（81.13）	45（64.29）

Note: “Blood transfusion” means whether blood transfusion was received during the operation. “Chemotherapy/Radiotherapy” means whether preoperative radiotherapy or chemotherapy was received.

Abbreviations: BMI, body mass index; DVT, deep venous thrombosis; FIB, fibrinogen; APTT, activated partial thromboplastin time; PT, prothrombin time; TT, thrombin time; Hgb, hemoglobin; Plt, platelet; TG, triglyceride; TC, total cholesterol; OS, open surgery; LS, laparoscopic surgery; SCC, squamous cell carcinoma; Non-SCA, NSCC, non-squamous cell carcinoma.

Then, we reviewed the laboratory examination of these patients during their hospitalization. It can be seen that the preoperative D-dimer and triglyceride levels in the DVT group were obviously higher than those in the non-DVT group, while preoperative plasma fibrinogen, APTT, PT, TT, hemoglobin, platelet, albumin, and total cholesterol levels in the 2 groups were roughly equal.

In addition, by comparing the surgical indicators of the 2 groups, we found that patients in the DVT group had a greater proportion of abdominal open surgery, a higher probability of intraoperative blood transfusion, and correspondingly, their surgical duration was clearly longer than that in the non-DVT group (P < .05).

Furthermore, we examined the tumor characteristics of these cervical cancer patients, such as tumor type, tumor stage, and history of preoperative radiotherapy and chemotherapy, which showed that the ratio of patients with advanced cervical cancer as well as those who had received preoperative chemotherapy or radiotherapy was higher in the DVT group (P < .05). While there was no remarkable difference in tumor type between the 2 groups. Thus, it was suggested that tumor stage and preoperative chemotherapy/radiotherapy are risk factors for postoperative DVT of lower limbs in cervical cancer patients, and the probability of DVT increases with the progression of the tumor.

In the univariate analysis mentioned above, we compared the various indicators of the 2 groups. We have found that advanced age, obesity, hypertension, diabetes, cardiovascular disease, high preoperative levels of plasma D-dimers and triglycerides, open surgery, long operation time, intraoperative blood transfusion, advanced tumors, and preoperative chemotherapy/radiotherapy are risk factors for postoperative lower limb DVT in patients with cervical cancer. According to the above conclusion, we used the factors with statistical differences in univariate analysis as independent variables and postoperative lower extremity DVT occurred (no = 0, yes = 1) as dependent variables, we included them in a multivariate logistic regression model for analysis (Table 2). After excluding the interaction between various factors by multivariate analysis, it was demonstrated that advanced age, obesity, high preoperative levels of D-dimer, and triglycerides, and open surgery are independent risk factors for postoperative lower extremity DVT in cervical cancer patients.

Table 2.

Multivariate Analysis of Cervical Cancer Complicated by Deep Venous Thrombosis.

Factors	β	SE	Wald χ2	P	OR	95% CI
Age	0.095	0.048	3.879	.043	1.237	1.007-1.519
BMI	0.213	0.105	4.112	.049	1.100	1.000-1.210
D-dimer	2.110	0.776	7.389	.007	8.245	1.801-37.739
TG	0.925	0.435	4.597	.039	1.365	1.004-1.557
Hypertension	0.316	0.708	0.199	.655	1.372	0.342-5.499
Diabetes	0.671	0.837	0.642	.423	1.956	0.379-10.098
Cardiovascular disease	1.310	1.027	1.628	.202	3.706	0.495-27.736
Surgical method	0.909	0.402	5.113	.026	3.618	1.168-11.211
Surgical duration	0.009	0.006	2.593	.107	1.009	0.998-1.020
Blood transfusion	0.599	0.774	0.598	.439	1.820	0.399-8.302
Tumor staging	0.767	0.713	1.159	.282	2.154	0.533-8.709
Chemotherapy/radiotherapy	0.865	0.767	1.270	.260	2.374	0.528-10.681

Abbreviations: BMI, body mass index; TG, triglyceride; DVT, deep venous thrombosis.

Discussion

Relationship Between DVT and Cancer

It is well-recognized that DVT and malignant tumors have a close relationship. ¹⁶ DVT is 4 to 7 times more likely to occur in cancer patients than in the general population, according to studies.^17,18 First off, malignant tumor cells have a potent pro-coagulant impact that can cause platelet aggregation to result in thrombus formation. In addition, patients with tumors frequently require more invasive procedures like intravenous catheterization, injections, etc, which can harm the vascular endothelium, upset the body's pro- and anticoagulation systems, and put the patient's blood in a hypercoagulable state, which can lead to thrombosis. Furthermore, vascular damage will be made worse by the fact that many patients with advanced malignant tumors need surgical treatment in addition to radiotherapy and chemotherapy. ¹⁹ Finally, cancer survivors generally experience prolonged bed rest and decreased activity due to the recovery and prognosis in the later stages. These result in sluggish blood flow and an elevated risk of thrombosis.

Once DVT occurs, it will substantially jeopardize the patient's safety and quality of life, as well as postpone the therapy progress of malignant tumors. According to a retrospective study, cancer patients with DVT have significantly poorer median survival times or overall survival rates than cancer patients without thrombosis. ³ To decrease the incidence and mortality of DVT and enhance the prognosis of cancer patients, early prevention, diagnosis, and treatment of DVT is, therefore, essential.

Incidence and Risk Factors Analysis

At present, cervical cancer is one of the main malignant tumors that harm women's health.^12,13 Most patients with cervical cancer can obtain satisfactory results with surgical treatment. ²⁰ However, in recent years, studies have found that the incidence of postoperative DVT is increased in cervical cancer patients, which will seriously affect the prognosis of patients.^21,22 Therefore, active intervention and prevention are particularly important for the therapy of patients. Our study retrospectively analyzed the clinical data of patients with cervical cancer, summarized the risk factors of postoperative DVT, and aimed to provide a scientific basis and targeted measures for its early diagnosis, prevention, and treatment.

Numerous studies have revealed that 11% to 40% of women who have gynecological surgery develop DVT.^23–25 In this study, individuals with cervical cancer had a postoperative DVT incidence of 24.8%. According to Lorchaivej et al, ²⁶ 11.6% of patients with gynecological cancers suffered postoperative DVT. However, retrospective research analyzed 135 gynecological cancer survivors and found that the incidence of DVT in lower limbs was 25.4%. ²⁷ Undeniably, the varied study design standards and the dearth of multicenter or big sample data studies may be to blame for these differences. In addition, 14 DVT patients developed pulmonary embolism in our research. These patients all received timely anticoagulation treatment (subcutaneous injection of 4100U low molecular weight heparin every 12 h) within 6 h of diagnosis.

In our study, age had a positive predictive value for postoperative DVT in cervical cancer patients. This is in line with the results of Lorchaivej et al. ²⁶ This might be because vascular sclerosis, increased blood viscosity, and dysfunctional venous valves are common in seniors. ²⁸ Also, it has been discovered that patients’ vascular endothelial cells produce more procoagulant compounds and fewer anticoagulant substances with the increase of age. ²⁹ Furthermore, poor venous blood flow occurs in elderly patients due to their substantially decreased activity and co-morbidity with chronic conditions. All of these elements have the potential to raise DVT risk either directly or indirectly. In order to reduce the incidence of DVT in the lower limbs, it is advised that elderly patients should increase their daily exercise routine, get out of bed as soon as possible after surgery, and be preventively treated with chemical anticoagulant drugs (subcutaneous injection of LMWH) combined with mechanical devices (such as intermittent inflating pressure pumps, gradient elastic socks, etc) in necessity.

D-dimer, one of the key elements of thrombosis, is a fibrin polymer that is crosslinked into a network of fibrin monomers by a series of events during fibrinolysis. Its rise signals hyperfibrinolysis and hypercoagulation in the body.^30,31 The plasma D-dimer level in the DVT group was substantially greater than that in the non-DVT group, according to this study's comparison of preoperative laboratory examination indicators between the 2 groups of cervical cancer patients. It should be emphasized that D-dimer is not a reliable predicted indicator of DVT. Numerous conditions such as infection, pregnancy, trauma, and DIC can cause an increase in D-dimer. ³² D-dimer was reported to have a 31.0% positive predictive value for DVT diagnosis and a 98.6% negative predictive value. ³³ D-dimer can therefore only be utilized as one of the straightforward screening approaches for the diagnosis of DVT.

This study demonstrated a close correlation between postoperative DVT and BMI. The greater the BMI, the higher the risk of DVT. Obesity has been linked to the development of idiopathic VTE in one-third of cases. ³⁴ Lilja et al ³⁵ pointed out that being overweight is a definite risk factor for some major diseases leading to DVT. In obese patients, increased plasminogen activator inhibitor-1 (PAI-1) down-regulates the conversion of plasminogen to plasmin by inhibiting the activation of plasminogen tissue to reduce the decomposition of fibrin clots, and finally, increases the risk of thrombosis. ³⁶

In addition to previous literature that reported that age, BMI, and D-dimer may be the risk factors for postoperative deep vein thrombosis, we also found that triglyceride levels were significantly elevated in DVT patients. This may be because TG is the center of lipid metabolism in the human body, and its elevated will lead to disorders of lipid metabolism, an increase of blood viscosity, platelet aggregation, and adhesion increase, which eventually results in DVT.^37,38 Hence, for those patients with elevated TG, it is necessary to adjust the diet, appropriately reduce the intake of calories, and increase the intake of soluble fiber to balance the energy expenditure and intake. At the same time, patients should do moderate exercise to consume excess body fat such as running, swimming, etc. When necessary, patients can take lipid-lowering drugs under the guidance of a professional endocrinologist.

Our data showed that the incidence of postoperative lower extremity DVT in laparoscopic surgery was much lower than in open surgery. This may be due to the fact that laparoscopic surgery results in less physical harm to the patient, less stress, less blood loss during the operation, and quicker postoperative recovery. It has been proved that individuals who underwent laparoscopic surgery experienced much shorter postoperative periods of time in bed, indwelling urine catheters, and hospital stays than those who received open surgery.^39,40 A retrospective analysis of 135 patients who underwent total hysterectomy for gynecological diseases revealed that compared to open surgery, laparoscopic surgery could significantly lower the incidence of intraoperative massive bleeding, postoperative DVT, and other complications while also enhancing patient quality of life. ⁴¹

Now there are many effective tools for thrombosis risk assessment in clinical practice (such as Caprini, Wells score, Autar scale, etc).^42,43 These tools classify the VTE risk of patients and give a few corresponding preventive measures, which can reduce the incidence of VTE to a certain extent. The most commonly used tool in our hospital is the Caprini risk assessment model (RAM). By comparing and analyzing the risk factors included in this scale with the results of our study, we can think that in addition to the known same factors (such as age, BMI, operation duration, and blood transfusion), hypertension, diabetes, cardiovascular disease, preoperative triglyceride level, and preoperative D-dimer level may also be included in the scope of consideration of this scale. However, because our research is retrospective and some medical records are incomplete, it is difficult to conduct a preoperative thrombosis risk assessment for all patients from the beginning. The reliability of the above-influencing factors still needs to be confirmed by subsequent prospective studies with larger samples.

Targeted Preventive Measures

It is worth discussing that in the univariate analysis of this study, we found that chronic diseases (hypertension, diabetes, and cardiovascular diseases), operation duration, intraoperative blood transfusion, tumor stage, and preoperative chemotherapy/radiotherapy may affect the occurrence of postoperative DVT in patients with cervical cancer. Taking those factors into consideration, clinicians need to strengthen the management of these patients by regulating their blood pressure, blood glucose, and cardiovascular conditions in a regular, systematic, and comprehensive manner. They should also pay attention to the diet, exercise, and lifestyle habits of the patients. It is recommended that these patients conduct positive self-regulation (such as healthy eating, moderate exercise, early to bed and getting up early, quitting smoking and drinking, etc), so as to strengthen cardiopulmonary function, avoid anxiety and tension, and finally reach the balance between psychological and physical health. In the meantime, operators must enhance their professional skills. Surgical operations should be standardized, gentle, precise, and fast to reduce surgical trauma stimulation, decrease intraoperative and postoperative bleeding, and lower the probability of blood transfusion. Moreover, the operator should pay attention to the placement of the patient's lower limb position during the operation, and ask the patient to do active or passive lower limb exercise during bed rest. Last but not least, family members can assist in massaging the lower limbs of patients to help patients with early ambulation, and the nurse needs to increase the publicity and education of nursing measures to prevent thrombosis.

Admittedly, for cancer patients with thrombotic risk factors, surgery remains the primary treatment option. However, early intervention and guidance are equally important for these patients. Our study analyzed the high-risk factors for thrombosis and proposed corresponding preventive measures for these factors. Compared to conventional perioperative management, these methods are actually more specific and advantageous. The methods described in our study can improve medical quality by enhancing communication and interaction between healthcare professionals and patients and their families, while also saving human resources and promoting patient recovery at the greatest economic cost. In addition, they not only provide direct treatment for patients but more importantly, guide them in self-management. Short-term treatments such as surgery and drugs should be combined with long-term optimized management to minimize the incidence rate of postoperative DVT and improve the quality of life of patients.

Limitations

There are certain shortcomings in this study. As it is a retrospective study, some patients were not included due to insufficient clinical information or loss of follow-up after discharge, which may affect the actual statistics of the occurrence of DVT in the lower limbs of patients after surgery. Moreover, this is a single-center study and the possibility of selection bias cannot be completely ruled out. The small sample size may directly affect the reliability of the results of statistical analyses and the representativeness of the cases. Therefore, further large-sample, multicenter prospective studies are needed to analyze in greater depth the incidence and risk factors for the occurrence of lower limb DVT in patients with cervical cancers after surgery to provide more reliable evidence for clinical prevention, diagnosis, and treatment of DVT.

Conclusions

In conclusion, old age, obesity, high preoperative plasma D-dimer level, increased preoperative triglyceride level, chronic diseases (hypertension, diabetes, and cardiovascular disease), open surgery, long operation time, intraoperative blood transfusion, advanced tumor, and preoperative chemotherapy/radiotherapy have crucial positive predictive value for postoperative low extremity DVT in patients with cervical cancer. Therefore, for cervical cancer patients with the above risk factors, we should give full attention, comprehensive assessment, and timely review of plasma D-dimer and lower extremity venous ultrasound. Clinicians should strengthen preoperative and postoperative management of high-risk patients, actively correct risk factors, and formulate reasonable and effective clinical prevention and treatment measures to reduce the occurrence of postoperative DVT in lower limbs and improve the survival rate and quality of life of patients.