Abstract
Objective
A large national database was conducted to examine in-hospital pressure ulcer(PU) development in patients who underwent peripheral thrombolysis and identify potential risk factors.
Source
A cohort of 120 744 adult patients from 2010 to 2019 was included in this study.
Methods
This retrospective analysis employed univariate and multivariate logistic regression analyses to examine the relationship between patient/hospital characteristics and the occurrence of PU in individuals who underwent peripheral thrombolysis. Patient factors considered included age, sex, race, comorbidities and complications, while hospital-level factors encompassed length of stay, cost, insurance type, bed size, admission type, hospital type, geographic location, and in-hospital mortality.
Results
Overall, 2.30% of patients developed PU. The rate of PU development varied annually between 2010 and 2019. Patients with PU were more likely to be non-elective admissions, hospitalized in northeastern regions, and insured by government programs rather than private insurance. PU development following peripheral vascular thrombolysis was linked to increased complications, higher healthcare costs, prolonged hospital stays, and elevated mortality rates. Patients with multiple comorbidities (three or more), chronic kidney disease, heart failure, anemia, weight loss, electrolyte imbalances, peripheral vascular disease, neurological disorders, and paraplegia were found to raise the risk of PU development. In addition, PU were associated with wound infection, wound dehiscence, pneumonia, urinary tract infection,bacteremia,cellulitis complications.
Conclusion
Our study unveiled the risk factors associated with the formation of in-hospital PU in patients receiving peripheral vascular thrombolysis therapy, in order to provide targeted prevention and improve management effectiveness.
Introduction
Peripheral vascular thrombolysis has emerged as a viable therapeutic option for a growing number of patients presenting with thrombotic diseases.1–3 Current evidence suggests that the rise in the demand for peripheral vascular thrombolysis is accompanied by an elevated risk of developing pressure ulcer(PU). 4 We believe that patients are prone to skin pressure injuries during thrombolytic therapy, mainly due to the following factors: firstly, patients receiving thrombolytic therapy may be at risk of poor blood circulation, as vascular recanalization and hemodynamic changes during thrombolysis can lead to unstable local tissue perfusion, which in turn can cause skin tissue damage due to ischemia and hypoxia. Secondly, thrombolytic drugs can cause the blood to be in a low coagulation state, increasing the risk of minor bleeding and exudation on of the skin, which in turn affects the integrity and resistance of the skin, making it more susceptible to damage when under pressure. Finally, during thrombolysis, patients must rest in bed and maintain the limb on the thrombolysis side to prevent the thrombolysis catheter from bending and affecting drug delivery. Therefore, patients undergoing catheter thrombolysis are more likely to develop skin pressure injuries. The incidence of PU ranges from 1.7% to 2.6%. 5 Traditionally, it has been understood that prolonged pressure, regardless of position, can lead to PU development.5–9 However, recent research indicates that PU are often multifactorial, particularly affecting elderly patients with multiple comorbidities.10–18 Given the increasing prevalence of peripheral vascular thrombolysis, it is imperative to prioritize strategies to reduce the occurrence of PU.
PU pose a significant health and economic challenge, negatively impacting both patient well-being and healthcare resource allocation.5,13,14,16–21 The estimated annual expenditure for treating PU in the United States falls within a wide range, from 68 000 to 239 000 US dollars. The detrimental effects of PU extend beyond complications, as they also contribute to increased nursing workload and healthcare costs.6,9,10,18,21,22 Consequently, from both a clinical and economic standpoint, reinforcing perioperative PU management is imperative.
To date, no research has been conducted on the rate of PU development following peripheral vascular thrombolysis and potential risk factors. We utilized a large national database to address these gaps by describing the occurrence of PU after thrombolysis and identifying comorbidities independently associated with this complication. Besides, the association of postoperative PU was assessed with certain variables such as age group, comorbidities, length of stay (LOS), regional distribution, and total healthcare costs. This study sought to pinpoint factors associated with PU formation following peripheral vascular thrombolysis. By determining the patient population most susceptible to this complication, we aimed to implement preventative measures to mitigate the incidence of PU.
Methods
Methodology and Data Source
Our retrospective descriptive study utilized data from the National Inpatient Sample (NIS) database, a nationally representative sample of U.S. hospitalizations. Patient-level variables, including age, sex, race/ethnicity, and comorbidities, and hospital-level variables, such as length of stay, total charges, payer source, bed size, admission type, hospital type, geographic location, and in-hospital mortality, were examined. As this study relied on publicly available and de-identified data, formal ethical approval was not required.
Methodology and Data Extraction
That we included patients undergoing catheter-directed peripheral vascular thrombolysis for (arterial, venous, both arterial and venous) occlusive disease. Patients who underwent peripheral vascular thrombolysis procedures between 2010 and 2019 were identified using International Classification of Diseases (ninth revision) clinical modifications (ICD-9-CM) and ICD-10-CM codes (9910/3E0531/3E0501) from the NIS database (n = 126 859) (Figure 1). PU were defined as those diagnosed during the hospitalization. In-hospital PUs were defined by using ICD-9-CM codes 707.0, 707.00–707.07, 707.09, 707.2, 707.20, 707.22, 707.23, and 707.25 and ICD-10-CM codes L89.

Exclusion process for patients undergoing peripheral vascular thrombolysis with PU.
Patients aged 18 or older with complete age data were included in this study, which led to the exclusion of 6115 cases (Figure 1). The remaining cases were categorized into two groups with or without PU. An assessment was conducted of hospital characteristics, patient demographics, clinical outcomes (LOS, in-hospital mortality, and total cost), and preoperative comorbidities (Table 1). Perioperative complications were identified using ICD-9-CM and ICD-10-CM codes from the hospital database. These complications included wound infection, wound dehiscence, pulmonary embolism, pneumonia, acute myocardial infarction, urinary tract infection, bacteremia, and cellulitis.
Patient Characteristics and Outcomes After Peripheral Vascular Thrombolysis Surgery (2010-2019).
Abbreviations: LOS, Length of stay; TOTCHE, Total charge.
Data Analysis
IBM SPSS Statistics 25.0 was used to analyze all data. Univariate and multivariate logistic regression (LR) analyses were employed to ascertain factors associated with PU development. χ2 tests were conducted to compare categorical variables between the two groups, while the Wilcoxon rank-sum test was utilized to assess significant differences in continuous variables. All relevant variables, including comorbidities, demographic factors, and hospital characteristics, were incorporated into the regression models. Univariate and multivariate logistic regression models were constructed to evaluate the association between perioperative complications, other comorbidities, and the occurrence of PU. Statistical significance was defined as a p-value less than .001. 23
Results
The Incidence of PU After Peripheral Vascular Thrombolysis Surgery
From 2010 to 2019, a total of 120 744 cases of peripheral vascular thrombolysis were identified in the NIS database. Overall, 3340 patients (2.30%) developed PU during this period (Table 1). PU occurrence fluctuated over time, declining from 2.3% in 2010 to 1.7% in 2019 (Figure 2). Among all the patients who developed pressure sores, a total of 618 cases had heel ulcers (ICD-9: 70707; ICD-10: L896) and 663 cases had sacral ulcers (ICD-9: 70705; ICD-10: L893) (Table 2).

Annual incidence of PU after peripheral vascular thrombolysis.
Pressure Ulcer Site.
Patient Demographics and Hospital Characteristics
A significantly higher proportion of patients who developed PU following peripheral vascular thrombolysis were hospitalized in facilities located in the Northeast region (21.60% vs 17.80%, p < .001) (Table 1, Figure 3E).

Patient demographics and hospital characteristics of the two groups.
Risk Factors and Outcomes Associated with PU
As shown in Table 1, patients with multiple comorbidities (n ≥ 3) were significantly more likely to develop PU following peripheral vascular thrombolysis (88.50% vs 63.20%, p < .001). Patients with PU exhibited a 2.6-fold increase in LOS compared to those without (13 days vs 5 days, p < .001) (Table 1). Patients with PU incurred significantly higher total hospitalization costs compared to those without (USD 125,904 vs USD 81,051, a 1.5-fold increase, p < .001) (Table 1). Regarding payer type, patients with PU were more likely to be covered by Medicare (72.10% vs 55.00%, p < .001) and less likely to be covered by private insurance (12.70% vs 22.60%, p < .001) or self-pay (1.80% vs 4.60%, p < .001) (Table 1, Figures 3D). As expected, death rates were markedly superior among patients with PU (10.50% vs 5.70%, a 1.8-fold increase, p < .001) (Table 1). (Figure 4)

The relationship between PU and patient/hospital characteristics.
Risk and Protective Factors for PU
We next performed LR analysis to reveal factors associated with PU development (Figure 3). Multiple comorbidities (n ≥ 3; OR = 4.467, 95% CI: 2.729-7.312, p < .001), deficiency anemia (OR = 1.785, 95% CI: 1.654-1.927, p < .001), chronic renal failure (OR = 1.937, 95% CI: 1.787-2.100, p < .001), congestive heart failure (OR = 1.689, 95% CI: 1.548-1.895, p < .001), weight loss (OR = 3.708, 95% CI: 3.406-4.036, p < .001), fluid and electrolyte imbalances (OR = 1.729, 95% CI: 1.605-1.863, p < .001), other neurological disorders (OR = 1.772, 95% CI: 1.598-1.965, p < .001), and paralysis (OR = 1.598, 95% CI: 1.467-1.740, p < .001) significantly raised the risk of PU formation (Figure 5). Conversely, private insurance (OR = 0.511, 95% CI: 0.488-0.622, p < .001), self-pay (OR = 0.461, 95% CI: 0.351-0.605, p < .001), and residence in the Midwest or North Central (OR = 0.722; CI = 0.648-0.806; p < .001), South (OR = 0.725; CI = 0.656-0.801; p < .001), or West (OR = 0.715; CI = 0.637-0.802; p < .001) regions were identified as protective factors against PU development.

The relationship between PU and preoperative comorbidities.
PU and Associated Complications After Peripheral Vascular Thrombolysis
Univariate analysis revealed that patients who developed PU following peripheral vascular thrombolysis experienced significantly more complications compared to those without PU, including wound infections, sepsis, wound dehiscence, pulmonary embolism, pneumonia, myocardial infarction, urinary tract infections, bacteremia, endocarditis, meningitis, and cellulitis (Figure 6). Multivariate analysis identified several complications as independent predictors for adverse outcomes in patients with PU. These included wound infection (OR = 1.777; CI = 1.433-2.205; p < .001), wound dehiscence (OR = 2.487; CI = 1.873-3.303; p < .001), pneumonia (OR = 1.579; CI = 1.443-1.727; p < .0001), urinary tract infection (OR = 2.087; CI = 1.912-2.279;p < .001), bacteremia (OR = 1.875; CI = 1.504-2.339;p < .001), and cellulitis (OR = 1.539; CI = 1.215-1.950; p < .001) (Figure 6). Surprisingly, pulmonary embolism(OR = 0.825; CI = 0.699-.974; p < 0.001) and acute myocardial infarction(OR = 0.746; CI = 0.646-0.862; p < .001) exhibit protective factors for PU.

The relationship between PU and postoperative complications.
Discussion
Herein, we conducted a comprehensive health and economic analysis of PU following peripheral vascular thrombolysis, examining their incidence and associated risk factors. The declining trend of annual incidence rates of PU between 2010 and 2019 suggests that implementing effective prevention strategies, such as postural changes, nutritional support, air mattress use, and early surgical intervention, can contribute to reducing these complications. The overall incidence of PU after peripheral vascular thrombolysis was 2.30% (Table 1).
In the present study, hospitalization in the Northeast region was independently associated with a higher risk of PUs development following peripheral vascular thrombolysis compared with other U.S. regions. Several potential explanations may account for the higher incidence of PUss observed in the Northeast. First, hospitals in this region may manage a higher proportion of medically complex patients, including those with advanced vascular disease, renal failure, heart failure, or multiple comorbidities, all of which are well-established risk factors for PUs development. 24 Second, regional variation in hospital characteristics—such as nurse staffing ratios, availability of specialized wound care teams, and adherence to standardized PUs prevention protocols—may contribute to differences in observed incidence. 25 Prior studies using national administrative databases have demonstrated substantial regional heterogeneity in both patient case mix and institutional resources, which can influence outcomes measured during hospitalization. 26 In addition, differences in documentation and coding practices across regions may partially explain the observed variation. 27 Taken together, these findings suggest that the higher rate of PUs observed in the Northeast likely reflects a combination of patient complexity, institutional practices, and regional documentation patterns rather than a purely geographic effect. Future studies incorporating detailed clinical data and hospital-level quality metrics will be necessary to better elucidate the mechanisms underlying regional variation in PUs risk among patients undergoing thrombolytic therapy.
The lower proportion of privately insured patients in the PU group suggests that socioeconomic factors may play a role in PU development. Some researchers have hypothesized that healthcare providers may subconsciously or consciously provide different levels of care to patients based on their perceived socioeconomic status.28,29 In addition, individuals with private insurance may, on average, have better baseline nutritional status, healthier lifestyles, and easier access to preventive healthcare services, all of which could contribute to a lower risk of PU development in this group. 30
Consistent with previous research,14–16 patients with multiple comorbidities (n ≥ 3) were more likely to develop PU following peripheral vascular thrombolysis. This association is likely due to poorer preoperative health, which can enhance the risk of complications following surgery. Previous studies have demonstrated that PU following peripheral vascular thrombolysis are associated with prolonged LOS, superior healthcare costs, and higher death rates.9,14,15,17,18,20–22,31–33 Postoperative issues such as complications, PU care, pain management, limited mobility, and inadequate family support can extend hospital stays.15,34–39 The additional cost results from extended hospital stays and the high cost of PU treatment and care.14,15,31,34 Research indicates that PU, in conjunction with vascular surgery, are associated with increased mortality rates.12,14,36,40,41
Chronic renal failure is frequently cited as a risk factor for PU development. This may be attributed to impaired kidney function, leading to the accumulation of toxins and excess fluid within the body. This accumulation can weaken and damage the skin and underlying tissues. Additionally, kidney failure patients often require bed dialysis, which can further compromise skin integrity by reducing tissue support and increasing susceptibility to skin sagging, ultimately contributing to PU formation (Figure 5). 42
Patients with chronic heart failure are at increased risk of developing PU. This may be attributed to reduced mobility, which can lead to prolonged periods of immobility and decreased tissue perfusion. Additionally, heart failure can cause systemic congestion and peripheral edema, further contributing to PU formation 43 (Figure 5).
Numerous studies have identified malnutrition-related factors, including anemia, weight loss, and electrolyte imbalances, as significant risk factors for PU development.9,11,12,15,16,31,34–36,40,44,45 This study further corroborated the relationship between weight loss and increased incidence of PU. Malnutrition frequently leads to a reduction in protective subcutaneous fat and connective tissue, rendering the skin more susceptible to pressure-induced injury and exposing bony prominences.9,12,31,44 Furthermore, weight loss is frequently associated with physical frailty, dehydration, reduced mobility, edema, and poor nutritional status, hindering the body's ability to repair damaged tissue and metabolize energy efficiently. 44 Effective strategies for PU management include a high-protein diet, regular repositioning, and correction of anemia17,18,21,46 (Figure 5).
Neurological disorders can compromise a patient's capacity to feel or recognize pain, leading to reduced sensitivity to painful or stressful stimuli and, ultimately, increased susceptibility to stress-related skin damage (Figure 5). 47
Paraplegic patients exhibited the highest incidence of PU, a correlation attributed to factors such as sensory impairment, dyskinesia, blood pressure fluctuations, and poor nutritional status (Figure 5).17,18,20,21,48
In our study, hypertension emerged as a protective factor against PU development following peripheral vascular thrombolysis. However, unlike a previous study, 11 no marked correlation was observed between hypertension and PU incidence. This discrepancy may be explained by the potential beneficial effects of hypertension on blood flow perfusion, which could reduce the risk of PU formation (Figure 5). 49
Our study identified a strong association between PU and several infectious complications, namely wound infection, wound dehiscence, pneumonia, urinary tract infection, bacteremia, and cellulitis (Figure 6). 10 These findings aligned with previous studies demonstrating a link between PU and infectious complications, including urinary tract infections, pneumonia, wound infections, bacteremia, and cellulitis. Patients with urinary tract infections may be at increased risk for PU development due to factors such as urinary incontinence and skin moisture.9,11,14,15,40,45 Patients with pneumonia, characterized by impaired inflammatory response, inadequate oxygenation, and limited mobility, are at increased risk of developing PU. 50 Compromised skin integrity can further exacerbate this risk by increasing susceptibility to infection, limiting mobility, and reducing functional capacity. 51 PU can serve as reservoirs for drug-resistant microorganisms, leading to local infections and, in severe cases, systemic bacteremia in hospitalized patients. 52 Patients with acute myocardial infarction, due to their weakened state, are particularly vulnerable to the development of PU. 53
An intriguing finding of our study was the lower incidence of both MI and PE in patients who developed PU. This observation contradicts the conventional assumption but is consistent across our analyses. While causality cannot be inferred, several non-mutually exclusive hypotheses may explain this association. Potent anticoagulant and antiplatelet drugs used for the treatment of MI/PE may indirectly reduce the risk of tissue ischemia and PU formation by improving blood perfusion throughout the body, including skin microcirculation. 54 On the other hand, such critically ill patients are usually transferred to the ICU or subject to more intensive vital sign monitoring. In this high-level care environment, preventive measures for PU (such as frequent changes in body position, the use of high-end pressure-reducing mattresses, and earlier nutritional support) are often implemented more standardly and strictly, thereby unexpectedly reducing the incidence of PU. 55
We now highlight that patients undergoing peripheral vascular thrombolysis who have multiple comorbidities, malnutrition, renal or cardiac dysfunction, or neurologic impairment should be prioritized for intensified PU prevention. Meanwhile, We also outline future research needs, including prospective validation of PU risk-prediction tools specific to thrombolysis patients and linkage of administrative data with richer clinical variables to better elucidate causal pathways and identify modifiable targets.
Our research has four limitations. Firstly, the NIS database used in our study only collects patient data during hospitalization. Therefore, it cannot evaluate the complications that occur after discharge. This shortcoming may lead to an underestimate of the incidence rate of PU, because only cases during hospitalization are recorded. The inability to track long-term outcomes also hinders a comprehensive understanding of the overall impact of peripheral vascular thrombolysis on PU and may limit the generalizability of research results in real-world clinical settings.36,45,56–59 Secondly, our study belongs to retrospective research, which is susceptible to selection and information bias, which may affect the accuracy of data collection.Thirdly, coding and documentation errors may occur when using an extensive administrative database.36,45,56–58 Finally, The NIS database does not contain laboratory data and the results of treatment, which makes it impossible to rule out certain confounding factors.
Conclusion
Given the significant clinical impact of PU following peripheral vascular thrombolysis, with a 2.30% incidence rate (Table 1), effective management strategies are essential. Between 2010 and 2019, the annual incidence of postoperative PU fluctuated. Several factors were identified as risk factors, including multiple comorbidities (n ≥ 3), chronic renal failure, congestive heart failure, chronic anemia, weight loss, fluid and electrolyte disturbances, peripheral vascular disease, neurological disorders, and paralysis. In contrast, private insurance, self-pay, and specific geographic locations (Midwest or North Central, South, West) were associated with lower risk. The occurrence of PU after peripheral vascular thrombolysis can result in various complications, increased healthcare costs, extended hospital stays, and higher mortality rates. To mitigate this risk, we employed an extensive database (NIS) to ascertain factors associated with PU development following peripheral vascular thrombolysis, enabling proactive intervention in high-risk patient populations.
CRediT Authorship Contribution Statement
All authors have made significant contributions to the conception, design, analysis, interpretation, drafting, and revision of the manuscript for this study. Jingping He: Research Design; Methodology;Software; Data Management; Formal Analysis; Writing Manuscript; Writing Review and Editing; Validation. Yingling Xue: Writing - Original Manuscript; Writing - Review and Editing. Yao Liu: Writing Manuscript; Writing Review and Editing. Ya Jiang: Writing Manuscript; Writing Review and Editing.Ying Wang: Writing Manuscript; Writing Review and Editing. Qinfeng Yang: Writing - Original Manuscript; Writing - Review and Editing - Data Management - Software. Jie Ding: Writing Review and Editing.
Footnotes
Funding
The authors received no financial support for the research, authorship, and/or publication of this article.
Declaration of Conflicting Interests
The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
