An Association between Chronic Obstructive Pulmonary Disease and Abdominal Aortic Aneurysm beyond Smoking

Incidence and risk factors for incisional hernia after open abdominal aortic aneurysm repair

INTRODUCTION

Incisional hernia (IH) is common after open abdominal aortic aneurysm (AAA) repair. Recent studies reported incidence rates higher than previously stated. The aim of this study was to quantify the IH incidence after open AAA surgery. The secondary outcome was to identify the risk factors associated with the development of an IH.

METHODS

Retrospective observational study of all consecutive patients who underwent an open repair of AAA, from January 2010 to June 2018, at our institution. Patients were free of abdominal wall hernias at the moment of inclusion in the study. Data were extracted from electronic records: baseline characteristics, surgical factors, and postoperative events. Computed tomography (CT) scans performed during follow-up were analyzed.

RESULTS

A total of 157 patients were analysed. The IH incidence after open repair of AAA was 46.5% (73 patients). The median time for IH development was 24.43 months (IQR: 10.40-45.27), while the median follow-up time was 37.20 months (IQR: 20.53-64.12). The risk factors linked to IH were: active (HR: 4.535; 95% CI: 1.369-15.022) or previous smoking habit (HR: 4.652; 95% CI: 1.430-15.131), chronic kidney disease (HR: 2.007; 95% CI: 1.162-3.467) and previous abdominal surgery (HR: 1.653; 95% CI: 1.014-2.695).

CONCLUSION

The incisional hernia after open abdominal aortic aneurysm repair affected a high proportion of the intervened patients. Previous abdominal surgery, chronic kidney disease, and smoking habit were independent factors for the development of an incisional hernia.

AAA Revisited: A Comprehensive Review of Risk Factors, Management, and Hallmarks of Pathogenesis

Despite declining incidence and mortality rates in many countries, the abdominal aortic aneurysm (AAA) continues to represent a life-threatening cardiovascular condition with an overall prevalence of about 2-3% in the industrialized world. While the risk of AAA development is considerably higher for men of advanced age with a history of smoking, screening programs serve to detect the often asymptomatic condition and prevent aortic rupture with an associated death rate of up to 80%. This review summarizes the current knowledge on identified risk factors, the multifactorial process of pathogenesis, as well as the latest advances in medical treatment and surgical repair to provide a perspective for AAA management.

Incidence and risk factors for incisional hernia after open abdominal aortic aneurysm repair

INTRODUCTION

Incisional hernia (IH) is common after open abdominal aortic aneurysm (AAA) repair. Recent studies reported incidence rates higher than previously stated. The aim of this study was to quantify the IH incidence after open AAA surgery. The secondary outcome was to identify the risk factors associated with the development of an IH.

METHODS

Retrospective observational study of all consecutive patients who underwent an open repair of AAA, from January 2010 to June 2018, at our institution. Patients were free of abdominal wall hernias at the moment of inclusion in the study. Data were extracted from electronic records: baseline characteristics, surgical factors, and postoperative events. Computed tomography (CT) scans performed during follow-up were analyzed.

RESULTS

A total of 157 patients were analysed. The IH incidence after open repair of AAA was 46.5% (73 patients). The median time for IH development was 24.43 months (IQR: 10.40-45.27), while the median follow-up time was 37.20 months (IQR: 20.53-64.12). The risk factors linked to IH were: active (HR: 4.535; 95% CI: 1.369-15.022) or previous smoking habit (HR: 4.652; 95% CI: 1.430-15.131), chronic kidney disease (HR: 2.007; 95% CI: 1.162-3.467) and previous abdominal surgery (HR: 1.653; 95% CI: 1.014-2.695).

CONCLUSION

The incisional hernia after open abdominal aortic aneurysm repair affected a high proportion of the intervened patients. Previous abdominal surgery, chronic kidney disease, and smoking habit were independent factors for the development of an incisional hernia.

Ex vivo expansion of regulatory T cells from abdominal aortic aneurysm patients inhibits aneurysm in humanized murine model

OBJECTIVE

Abdominal aortic aneurysm (AAA) is a chronic inflammatory disease. Studies of human aneurysm tissue demonstrate dense inflammatory cell infiltrates with CD4+ T cells predominating. Regulatory T cells (Tregs) play an important role in inhibiting pro-inflammatory T cell proliferation, therefore, limiting collateral tissue destruction. The aim of this study was to investigate whether ex vivo augmentation of human Tregs attenuates aneurysm formation in humanized murine model of AAA.

METHODS

Circulating Treg population in AAA patients and age- and gender-matched controls were determined by real-time polymerase chain reaction and flow cytometry. To create humanized murine model of AAA, irradiated Rag1-deficient (Rag1-/-) mice, without mature T lymphocytes, at 7 weeks of age were given 5 × 106 of human CD4+ T cells intraperitoneally. Then the mice underwent CaCl2 aneurysm induction. Aortic diameters were measured before and at 6 weeks after aneurysm induction. Aortic tissue was collected for histology and protein extraction. Verhoeff-Van Gieson stain was used for staining elastic fiber. CD4+ T cells in the aortic tissue were detected by immunohistochemical staining.

RESULTS

In human peripheral blood mononuclear cells, the proportion of Tregs are decreased in AAA patients compared with matched control patients with significant vascular disease. We first validated the role of Tregs in the CaCl2 model of AAA. To determine the role of human T cells in AAA formation, Rag1-/- mice, resistant to CaCl2-aneurysm induction, were transplanted with human CD4+ T cells. Human CD4+ T cells were able to drive aneurysm formation in Rag1-/- mice. We show that ex vivo augmentation of human Tregs by interleukin-2 resulted in decreased aneurysm progression.

CONCLUSIONS

These data suggest that the ex vivo expansion of human Tregs may be a potential therapeutic strategy for inhibiting progression of AAA.

Leukocyte subsets and abdominal aortic aneurysms detected by screening in men

OBJECTIVE

In the present case-control study, we describe the associations between leukocyte subsets in blood and early, screening-detected AAA in men. An abdominal aortic aneurysm (AAA) may result in a life-threatening rupture of the aortic wall. The trigger for AAA formation remains unknown, but the vascular adventitia of advanced AAAs is infiltrated by various leukocytes, indicating that the pathogenesis may involve inflammation.

METHODS

In Sweden, all 65-year-old men are invited to an ultrasound examination for detection of AAA. At the Gothenburg screening site, 16 256 men were examined in 2013-2017, 1.2% of whom had an AAA (diameter of the infrarenal aorta ≥30 mm). All men with AAA at screening as well as a randomized selection of AAA-free screened men were invited to participate in a case-control study.

RESULTS

The median diameter of AAAs was 33 mm. Men with an AAA (n = 151) had a higher frequency of smoking, hypertension and statin use than controls (n = 224). Blood levels of neutrophils, lymphocytes, monocytes and basophils were higher in individuals with an AAA, but eosinophil count did not differ from controls. Odds ratios (95% confidence interval) for AAA were 8.6 (4.2-17.4), 3.5 (1.9-6.6) and 3.3 (1.8-6.3) for the highest versus lowest quartile of neutrophils, lymphocytes and monocytes, respectively. For neutrophils and lymphocytes, the association with AAA remained significant after adjustment for smoking and other known risk factors/markers.

CONCLUSION

Several, but not all, subsets of circulating leukocytes are associated with screening-detected AAA in men, which is insufficiently explained by associations with smoking and other confounders.

Lung-derived HMGB1 is detrimental for vascular remodeling of metabolically imbalanced arterial macrophages

Pulmonary disease increases the risk of developing abdominal aortic aneurysms (AAA). However, the mechanism underlying the pathological dialogue between the lungs and aorta is undefined. Here, we find that inflicting acute lung injury (ALI) to mice doubles their incidence of AAA and accelerates macrophage-driven proteolytic damage of the aortic wall. ALI-induced HMGB1 leaks and is captured by arterial macrophages thereby altering their mitochondrial metabolism through RIPK3. RIPK3 promotes mitochondrial fission leading to elevated oxidative stress via DRP1. This triggers MMP12 to lyse arterial matrix, thereby stimulating AAA. Administration of recombinant HMGB1 to WT, but not Ripk3^-/- mice, recapitulates ALI-induced proteolytic collapse of arterial architecture. Deletion of RIPK3 in myeloid cells, DRP1 or MMP12 suppression in ALI-inflicted mice repress arterial stress and brake MMP12 release by transmural macrophages thereby maintaining a strengthened arterial framework refractory to AAA. Our results establish an inter-organ circuitry that alerts arterial macrophages to regulate vascular remodeling.

High prevalence of abdominal aortic aneurysms in patients with lung cancer

BACKGROUND

Lung cancer and abdominal aortic aneurysms (AAAs) possess multiple shared risk factors. Whereas both have screening guidelines in place, they vary in methodology despite having significant overlap in populations of patients screened.

METHODS

Our hospital system's Lung Cancer Program database was used to identify patients diagnosed with primary lung cancer within the past 15 years. Demographic and risk factor data were obtained, and patients' original positron emission tomography-computed tomography scans were re-read for measurements of the abdominal aorta (aortic diameter ≥3.0 cm). A cancer-free control group was obtained for comparison. Multilinear regression modeling was used to evaluate the independent associations of multiple variables on the presence of AAA.

RESULTS

Among 814 patients with primary lung cancer, 90 (11.1%; 95% confidence interval [CI], 8.9%-13.3%) had AAA compared with 4 of 200 (2%; 95% CI, 0.1%-3.9%) in the control group (P = .0001). Patients who smoked were more likely than nonsmokers to have AAA (11.9% [95% CI, 9.8-14.6] vs 2.2% [95% CI, 0.1-8.1]; P = .0021). In patients with AAA, 12% (11/90) had aneurysms that required treatment, and 76.6% had early-stage lung cancer. Women in our study also had a high prevalence of AAA (4.6%). Logistic regression analysis showed male sex (odds ratio [OR], 3.70; P <.001), increasing age (OR, 1.07 per year; P <.001), smoking amount (OR, 1.01 per pack-year; P = .004), and hypertension (OR, 2.30; P = .020) to be independent risk factors for AAA.

CONCLUSIONS

Patients with lung cancer have a high prevalence of AAA. If future studies can demonstrate a reduction in AAA mortality by screening for AAA and lung cancer simultaneously, it may prove worthwhile to extend the low-dose computed tomography scan through the lower abdomen in select patients.

Association of simple renal cysts and chronic kidney disease with large abdominal aortic aneurysm

Background

Abdominal aortic aneurysms (AAA) primarily affect men over 65 years old who often have many other diseases, with similar risk factors and pathobiological mechanisms to AAA. The aim of this study was to assess the prevalence of simple renal cysts (SRC), chronic kidney disease (CKD), and other kidney diseases (e.g. nephrolithiasis) among patients presenting with AAA.

Methods

Two groups of patients (97 AAA and 100 controls), with and without AAA, from the Surgical Clinic Charité, Berlin, Germany, were selected for the study. The control group consisted of patients who were evaluated for a kidney donation (n = 14) and patients who were evaluated for an early detection of a melanoma recurrence (n = 86). The AAA and control groups were matched for age and sex. Medical records were analyzed and computed tomography scans were reviewed for the presence of SRC and nephrolithiasis.

Results

SRC (74% vs. 57%; p<0.016) and CKD (30% vs. 8%; p<0.001) were both more common among AAA than control group patients. On multivariate analysis, CKD, but not SRC, showed a strong association with AAA.

Conclusions

Knowledge about pathobiological mechanisms and association between CKD and AAA could provide better diagnostic and therapeutic approaches for these patients.

Comorbidities Associated with Large Abdominal Aortic Aneurysms

Background  Abdominal aortic aneurysm has become increasingly important owing to demographic changes. Some other diseases, for example, cholecystolithiasis, chronic obstructive pulmonary disease, and hernias, seem to co-occur with abdominal aortic aneurysm. The aim of this retrospective analysis was to identify new comorbidities associated with abdominal aortic aneurysm.

Methods  We compared 100 patients with abdominal aortic aneurysms and 100 control patients. Their preoperative computed tomographic scans were examined by two investigators independently, for the presence of hernias, diverticulosis, and cholecystolithiasis. Medical records were also reviewed. Statistical analysis was performed using univariate analysis and multiple logistic regression analysis.

Results  The aneurysm group had a higher frequency of diverticulosis ( p  = 0.008). There was no significant difference in the occurrence of hernia ( p  = 0.073) or cholecystolithiasis ( p  = 1.00). Aneurysm patients had a significantly higher American Society of Anesthesiology score (2.84 vs. 2.63; p  = 0.015) and were more likely to have coronary artery disease ( p  < 0.001), congestive heart failure ( p  < 0.001), or chronic obstructive pulmonary disease ( p  < 0.001). Aneurysm patients were more likely to be former ( p  = 0.034) or current ( p  = 0.006) smokers and had a significantly higher number of pack years ( p  < 0.001). Aneurysm patients also had a significantly poorer lung function. In multivariate analysis, the following factors were associated with aneurysms: chronic obstructive pulmonary disease (odds ratio, OR = 12.24; p  = 0.002), current smoking (OR = 4.14; p  = 0.002), and coronary artery disease (OR = 2.60; p  = 0.020).

Conclusions  Our comprehensive analysis identified several comorbidities associated with abdominal aortic aneurysms. These results could help to recognize aneurysms earlier by targeting individuals with these comorbidities for screening.

Prospective study of lung function and abdominal aortic aneurysm risk: The Atherosclerosis Risk in Communities study

BACKGROUND AND AIMS

No prospective study has investigated whether individuals with respiratory impairments, including chronic obstructive pulmonary disease (COPD) and restrictive lung disease (RLD), are at increased risk of abdominal aortic aneurysm (AAA). We aimed to prospectively investigate whether those respiratory impairments are associated with increased AAA risk.

METHODS

In 1987-1989, the Atherosclerosis Risk in Communities (ARIC) study followed 14,269 participants aged 45-64 years, without a history of AAA surgery, through 2011. Participants were classified into four groups, "COPD" [forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC)

RESULTS

During the 284,969 person-years of follow-up, 534 incident AAA events were documented. In an age, sex, and race-adjusted proportional hazards model, individuals with respiratory impairments had a significantly higher risk of AAA than the normal reference group. After adjustment for AAA risk factors, including smoking status and pack-years of smoking, AAA risk was no longer significant in the respiratory symptoms with normal spirometry group [HR (95% CI), 1.25 (0.98-1.60)], but was still increased in the other two groups [RLD: 1.45 (1.04-2.02) and COPD: 1.66 (1.34-2.05)]. Moreover, continuous measures of FEV1/FVC, FEV1 and FVC were associated inversely with risk of AAA.

CONCLUSIONS

In the prospective population-based cohort study, obstructive and restrictive spirometric patterns were associated with increased risk of AAA independent of smoking, suggesting that COPD and RLD may increase the risk of AAA.

Collapse

Key Words

• Abdominal aortic aneurysm
• COPD
• Epidemiology
• Lung function

Collapse

MESH Headings

• Aortic Aneurysm, Abdominal/diagnostic imaging
• Aortic Aneurysm, Abdominal/epidemiology
• Female
• Forced Expiratory Volume
• Humans
• Incidence
• Lung/physiopathology
• Male
• Middle Aged
• Prognosis
• Prospective Studies
• Pulmonary Disease, Chronic Obstructive/diagnosis
• Pulmonary Disease, Chronic Obstructive/epidemiology
• Pulmonary Disease, Chronic Obstructive/physiopathology
• Risk Assessment
• Risk Factors
• Spirometry
• Time Factors
• United States/epidemiology
• Vital Capacity

Collapse

Grants

• HHSN268201100012C NHLBI NIH HHS
• HHSN268201100010C NHLBI NIH HHS
• HHSN268201100008C NHLBI NIH HHS
• HHSN268201100007C NHLBI NIH HHS
• HHSN268201100011I NHLBI NIH HHS
• HHSN268201100011C NHLBI NIH HHS
• HHSN268201000011C NHLBI NIH HHS
• HHSN268201100006C NHLBI NIH HHS
• HHSN268201100005I NHLBI NIH HHS
• R01 HL103695 NHLBI NIH HHS
• HHSN268201100009I NHLBI NIH HHS
• HHSN268201000012C NHLBI NIH HHS
• HHSN268201100005G NHLBI NIH HHS
• HHSN268201100008I NHLBI NIH HHS
• HHSN268201100009C NHLBI NIH HHS
• HHSN268201100005C NHLBI NIH HHS
• HHSN268201100007I NHLBI NIH HHS
• HHSN268201000010C NHLBI NIH HHS

Collapse

Affiliation(s)

Yasuhiko Kubota Division of Epidemiology and Community Health, School of Public Health, University of Minnesota, Minneapolis, MN, USA.
Aaron R Folsom Division of Epidemiology and Community Health, School of Public Health, University of Minnesota, Minneapolis, MN, USA
Kunihiro Matsushita Department of Epidemiology and the Welch Center for Prevention, Epidemiology and Clinical Research, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA
David Couper Department of Biostatistics, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, NC, USA
Weihong Tang Division of Epidemiology and Community Health, School of Public Health, University of Minnesota, Minneapolis, MN, USA

Collapse

Microarray analysis to identify the similarities and differences of pathogenesis between aortic occlusive disease and abdominal aortic aneurysm

Objectives Expression profile of GSE57691 was analyzed to identify the similarities and differences between aortic occlusive disease and abdominal aortic aneurysm. Methods The expression profile of GSE57691 was downloaded from Gene Expression Omnibus database, including 20 small abdominal aortic aneurysm samples, 29 large abdominal aortic aneurysm samples, 9 aortic occlusive disease samples, and 10 control samples. Using the limma package in R, the differentially expressed genes were screened. Followed by enrichment analysis was performed for the differentially expressed genes using database for annotation, visualization, and integrated discovery online tool. Based on string online tool and Cytoscape software, protein-protein interaction network and module analyses were carried out. Moreover, integrated TF platform database and Cytoscape software were used for constructing transcriptional regulatory networks. Results As a result, 1757, 354, and 396 differentially expressed genes separately were identified in aortic occlusive disease, large abdominal aortic aneurysm, and small abdominal aortic aneurysm samples. UBB was significantly enriched in proteolysis related pathways with a high degree in three groups. SPARCL1 was another gene shared by these groups and regulated by NFIA, which had a high degree in transcriptional regulatory network. ACTB, a significant upregulated gene in abdominal aortic aneurysm samples, could be regulated by CLIC4, which was significantly enriched in cell motions. ACLY and NFIB were separately identified in aortic occlusive disease and small abdominal aortic aneurysm samples, and separately enriched in lipid metabolism and negative regulation of cell proliferation. Conclusions The downregulated UBB, NFIA, and SPARCL1 might play key roles in both aortic occlusive disease and abdominal aortic aneurysm, while the upregulated ACTB might only involve in abdominal aortic aneurysm. ACLY and NFIB were specifically involved in aortic occlusive disease and small abdominal aortic aneurysm separately.

Impact of chronic obstructive pulmonary disease on patients with aortic aneurysms: a nationwide retrospective cohort study in Taiwan

OBJECTIVES

Aortic aneurysm (AA) is a leading cause of death worldwide. Chronic obstructive pulmonary disease (COPD) is a risk factor for AA, and the prognoses of COPD patients with AA who underwent/did not undergo an operation warrant investigation.

DESIGN

A nationwide retrospective cohort study.

SETTING

We included patients with AA older than 18 years who received their first AA diagnosis between 2005 and 2011 in Taiwan.

PARTICIPANTS

This study enrolled 3263 COPD patients with AA before propensity score matching and 2127 COPD patients with AA after propensity score matching.

OUTCOME MEASURES

The main outcomes were all-cause mortality and rehospitalisation for AA or operation. The outcomes of COPD patients with AA and COPD patients without AA during an 8-year follow-up period were examined using Cox proportional hazards models.

RESULTS

In the AA population, patients with COPD showed higher rates of mortality and rehospitalisation than patients without COPD with adjusted HRs of 1.12 (95% CI 1.03 to 1.22) and 1.11 (95% CI 1.01 to 1.23), respectively, after propensity score matching. Analysis of the patients who underwent an operation revealed that the rates of mortality of COPD and non-COPD patients were not significantly different. In contrast, among the patients who did not receive an operation, patients with COPD showed a higher mortality rate than patients without COPD with an adjusted HR of 1.11 (95% CI 1.0 to 1.22).

CONCLUSIONS

The outcomes of COPD patients with AA undergoing an operation were improved, but the mortality rate of non-COPD patients with AA remained high. An effective treatment to reduce mortality in this group warrants further investigation.

What are the Prevalence of Abdominal Aortic Aneurysm in Patients with Chronic Obstructive Pulmonary Diseases and the Characteristics of These Patients?

OBJECTIVE

To determine the prevalence of abdominal aortic aneurysm (AAA) in patients with chronic obstructive pulmonary disease (COPD) and to assess the characteristics of these patients.

MATERIALS AND METHODS

Stable COPD patients (age, >40 years) were included in the study between January 2014 and June 2014. Patients with acute exacerbations and a previous lung resection were excluded. Data regarding demographic characteristics were recorded. The modified Medical Research Council (mMRC) dyspnea scale was used to assess the severity of breathlessness. The COPD Assessment Test (CAT) was performed. Abdominal aortic diameter was measured using abdominal ultrasonography (AUS), and AAA was diagnosed as an aortic diameter of ≥30 mm at the renal artery level.

RESULTS

In total, 82 patients were examined. AAA was detected in five (6.1%) patients. Diabetes mellitus, hypertension, and coronary artery disease were present in four patients with AAA. The average mMRC score was 3.2±0.4, and the mean CAT score was 18.4±6.0. Aneurysmal diameter was >50 mm in four patients and 37 mm in one patient. Statistically significant differences were found between patient with AAA and those without AAA with respect to the mean abdominal aortic diameters at the renal artery and iliac artery levels (p=0.012 and 0.002, respectively).

CONCLUSION

Our findings suggest that AAA is associated with COPD, with a prevalence rate of 6.1%. AAA is usually asymptomatic until a clinical status of rupture, which is associated with a higher mortality risk. Early diagnosis of AAA is lifesaving. In COPD patients, AAA might be easily determined using AUS, which is a noninvasive and relatively cheap procedure.

Transition from Open Surgery to Endovascular Treatment of Abdominal Aortic Aneurysm Rupture

BACKGROUND

To review the outcome before and after the implementation of protocol-based strategy for endovascular repair (EVAR) of abdominal aortic aneurysm rupture (rAAA).

METHODS

A retrospective analysis of prospectively collected data from a tertiary center during the period 2006-2011. Demographics, comorbidities, blood examinations, perioperative patients' status, and mortality rates were recorded. Univariate and multivariate analyses were used to assess the association of the type of the procedure with various factors.

RESULTS

A total of 58 (46 open surgical repair [OSR] and 12 EVAR) patients with mean age of 74 ± 17 years (91% males) were treated for rAAA. However, 39 (11 EVAR and 28 OSR) were operated with protocol-based strategy available. Total mortality rate was 52.6% (10 of 19) initially and 38.5% (15 of 39) after the implementation of a protocol-based strategy. During protocol-based treatment, the survival rate did not differ between the 2 procedures (7 of 11 EVAR and 17 of 28 OSR; P, ns). A 30-day mortality rate was associated with preoperative number of platelets (unadjusted P values, P = 0.013), age (odds ratio [OR] 0.796; 95% confidence interval [CI], 0.685-0.925; P = 0.003), and diastolic blood pressure (OR, 1.053; 95% CI, 1.016-1.093; P = 0.005). After mean follow-up of 48 ± 11 months, EVAR patients presented better outcome regarding mortality rate (36% OSR vs. 0% EVAR; P = 0.0464).

CONCLUSIONS

After the adoption of an available rEVAR protocol-based strategy, EVAR and OSR were equally effective during postoperative 30 days. The role of hypotension and age is important on poor outcomes during this period. However, after midterm follow-up, EVAR demonstrates better survival rates than OSR.

A Meta-Analysis of the Association of Chronic Obstructive Pulmonary Disease with Abdominal Aortic Aneurysm Presence

BACKGROUND

Several case-control and population-based abdominal aortic aneurysm (AAA) screening studies have reported inconclusive results of the association of chronic obstructive pulmonary disease (COPD) with AAA presence. To determine whether COPD is associated with AAA presence, we performed a meta-analysis of contemporary clinical studies.

METHODS

To identify all contemporary case-control and population-based AAA screening studies evaluating the association of COPD with AAA presence, databases including MEDLINE and EMBASE were searched from January 2000 to May 2015 using Web-based search engines (PubMed and OVID). An adjusted odds ratio (OR) and 95% confidence intervals (CI) for COPD or AAA presence (using multivariable logistic regression) were abstracted from each individual study. We took an OR for AAA presence to be representative of an OR for COPD presence.

RESULTS

Of 159 potentially relevant articles screened initially, there were 7 case-control and 4 population-based AAA screening studies that met eligibility requirements and were included. Pooled analysis of all the 11 studies (14 estimates, 155,731 participants), 7 case-control studies (4171 participants), and 4 population-based AAA screening studies (7 estimates, 151,560 participants) respectively demonstrated a statistically significant 1.78-fold (OR 1.78, 95% CI 1.38-2.30, P < 0.00001), 3.05-fold (OR 3.05, 95% CI 1.44-6.49, P = 0.004), and 1.24-fold (OR 1.24, 95% CI 1.04-1.48, P = 0.02) increased prevalence/incidence of COPD in patients with AAA relative to subjects without AAA (i.e., a statistically significant 1.78-, 3.05-, and 1.24-fold increased prevalence/incidence of AAA in patients with COPD relative to subjects without COPD) (P for subgroup differences = 0.02).

CONCLUSION

The present meta-analysis demonstrated 1.8-fold increased prevalence/incidence of COPD in patients with AAA relative to subjects without AAA (i.e., 1.8-fold increased prevalence/incidence of AAA in patients with COPD relative to subjects without COPD), which suggests that COPD is associated with AAA presence.

Chronic obstructive pulmonary disease effect on the prevalence and postoperative outcome of abdominal aortic aneurysms: A meta-analysis

Epidemiologic evidence suggested chronic obstructive pulmonary disease (COPD) might increase risk for abdominal aortic aneurysm (AAA). However, the association between COPD and AAA remains inconclusive. We searched PubMed and Cochrane databases until June 2015. Forty-eight articles were included for meta-analysis. COPD was found to be positively associated with AAA, regardless of study design and smoking status. AAA mortality is higher among COPD patients compared with non-COPD patients (postoperative [adjusted OR 2.11; 95% CI 1.33–3.34]; long-term [adjusted OR 1.70; 95% CI 1.37–2.12]). But the association between postoperative mortality and COPD was not found to be significant in patients underwent endovascular aneurysm repair (mixed OR 2.53; 95% CI 0.70–9.18). Rupture AAA may increase the postoperative mortality in COPD patients (rupture [adjusted OR 4.75; 95% CI 2.07–10.89]; non-rupture [adjusted OR 1.97; 95% CI 1.11–3.49]). The AAA postoperative morbidity was found to be positively associated with COPD (adjusted OR 1.59; 95% CI 1.14–2.21). Increased COPD severity may increase the long-term mortality (medical versus oxygen dependent: [OR 1.26; 95% CI 1.07–1.49] versus [OR 2.79; 95% CI 2.24–3.49]). In conclusion, COPD may increase the risk of AAA, morbidity and mortality of AAA patients underwent endovascular aortic repair.

Effects of doxycycline on local and systemic inflammation in stable COPD patients, a randomized clinical trial

Neutrophilic inflammation plays a causal role in Chronic Obstructive Pulmonary Disease (COPD). Neutrophil derived myeloperoxidase(MPO) matrix metalloproteinases(MMP's), and elastases are thought to contribute to the perpetuation of the disease. The tetracycline analogue doxycycline has been shown to inhibit neutrophil-mediated inflammation. It was thus reasoned that doxycycline may attenuate neutrophil-mediated inflammation in COPD.

METHODS

In this double blind randomized controlled trial the effect of a 3-week course of doxycycline on sputum and systemic inflammatory parameters was evaluated in stable COPD patients. In order to exclude inflammation by bacterial colonisation patients must have 2 negative sputum cultures in the previous year. The effect of doxycycline treatment on inflammatory markers (TNF-α, IL-1β and IL-6) and neutrophil specific markers in sputum (MPO, MMP's, and IL-8) and serum C-reactive protein was evaluated. Sputum was obtained by sputum induction with hypertonic saline.

RESULTS

A total of 41 patients were included. Ten patients were excluded as they were not able to produce sputum at the first or second visit. Baseline characteristics were similar in the two groups. In the remaining patients doxycycline did not influence sputum MPO concentrations. Also MMP-8 and 9, IL-6 and IL-8 concentrations as well as lung function parameters were not affected by doxycycline. Systemic inflammation by means of CRP was also not influenced by doxycycline.

CONCLUSION

A three week course of doxycycline did not influence MPO sputum levels nor any of the other inflammatory sputum and systemic markers.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT00857038 URL: clinicaltrials.gov.

Screening of COPD patients for abdominal aortic aneurysm

Purpose

Screening for abdominal aortic aneurysm (AAA) in “men aged over 65 years who have ever smoked” is a recommended policy. To reduce the number of screenings, it may be of value to define subgroups with a higher prevalence of AAA. Since chronic obstructive pulmonary disease (COPD) and AAA are associated with several common risk factors, this study investigates the prevalence of AAA in COPD patients.

Patients and methods

Patients with COPD were identified via the hospital information system. Inclusion criteria were: COPD stage I–IV, ability to give full consent, and age >18 years; exclusion criteria were: patient too obese for an ultrasound check, previously diagnosed AAA, prior surgery for AAA, or ethical grounds such as concomitant advanced malignant or end-stage disease. The primary endpoint of the study was an aortic diameter measured by ultrasound of ≥30 mm. Defined secondary endpoints were evaluated on the basis of medical records and interviews.

Results

Of the 1,180 identified COPD patients, 589 were included in this prospective study. In 22 patients (3.70%), the aortic diameter was ≥30 mm, representing an AAA prevalence of 6.72% among males aged >65 years. The risk of AAA increased with the following comorbidities/risk factors: male sex (odds ratio [OR] 2.98), coronary heart disease (OR 2.81), peripheral arterial occlusive disease (OR 2.47), hyperlipoproteinemia (OR 2.77), AAA in the family history (OR 3.95), and COPD stage I/II versus IV (OR 1.81).

Conclusion

The overall AAA prevalence of 3.7% in our group of COPD patients is similar to that of the general population aged >65 years. However, the frequency of AAA in male COPD patients aged >65 years is considerably higher (6.72%) and increased further still in those individuals with additional comorbidities/risk factors. Defining subgroups with a higher risk of AAA may increase the efficiency of screening.

The pathophysiologic basis of abdominal aortic aneurysm progression: a critical appraisal

An aneurysm of the abdominal aorta is a common pathology and a major cause of sudden death in the elderly. Currently, abdominal aortic aneurysms (AAAs) can only be treated by surgery and an effective medical therapy is urgently missing. The pathophysiology of AAAs is complex and is believed to be best described as a comprehensive inflammatory response with an accompanying proteolytic imbalance; the latter being held responsible for the progressive weakening of the aortic wall. Remarkably, while interference in inflammatory and/or proteolytic cascades proves highly effective in preclinical studies, emerging clinical studies consistently fail to show a benefit. In fact, some anti-inflammatory interventions appear to adversely influence the disease process. Altogether, recent clinical observations not only challenge the prevailing concepts of AAA progression, but also raise doubt on the translatability of findings from rodent models for growing AAA.

Population risk factor estimates for abdominal aortic aneurysm from electronic medical records: a case control study

BACKGROUND

Using abdominal aortic aneurysm (AAA) as a model, this case-control study used electronic medical record (EMR) data to assess known risk factors and identify new associations.

METHODS

The study population consisted of cases with AAA (n =888) and controls (n =10,523) from the Geisinger Health System EMR in Central and Northeastern Pennsylvania. We extracted all clinical and diagnostic data for these patients from January 2004 to December 2009 from the EMR. From this sample set, bootstrap replication procedures were used to randomly generate 2,500 iterations of data sets, each with 500 cases and 2000 controls. Estimates of risk factor effect sizes were obtained by stepwise logistic regression followed by bootstrap aggregation. Variables were ranked using the number of inclusions in iterations and P values.

RESULTS

The benign neoplasm diagnosis was negatively associated with AAA, a novel finding. Similarly, type 2 diabetes, diastolic blood pressure, weight and myelogenous neoplasms were negatively associated with AAA. Peripheral artery disease, smoking, age, coronary stenosis, systolic blood pressure, age, height, male sex, pulmonary disease and hypertension were associated with an increased risk for AAA.

CONCLUSIONS

This study utilized EMR data, retrospectively, for risk factor assessment of a complex disease. Known risk factors for AAA were replicated in magnitude and direction. A novel negative association of benign neoplasms was identified. EMRs allow researchers to rapidly and inexpensively use clinical data to expand cohort size and derive better risk estimates for AAA as well as other complex diseases.

Comorbidity Distribution, Clinical Expression and Survival in COPD Patients with Different Body Mass Index

Rationale: Contrary to the general population, in patients with chronic obstructive pulmonary disease (COPD) a low body mass index (BMI) is associated with excess mortality, while obesity appears protective (obesity paradox). We hypothesized that BMI is associated with a distinct number and expression of comorbidities in patients with COPD. The type of comorbidity may relate to mortality variability. Objectives and Methods: We followed 1659 COPD patients for a median of 51 months [IQR 27-77] with detailed comorbidity records and tracking pulmonary function, exercise capacity, dyspnea, health status, and cause of death. The cohort was categorized into the 5 National Heart Lung and Blood Institute (NHLBI) BMI groups with determination made about each group's relationship to specific comorbidities, clinical parameters and risk for death. Results: Whereas osteoporosis, substance abuse, abdominal aortic aneurism and peripheral arterial disease were more prevalent in patients with low BMI, metabolic and cardiac problems were more frequent in those with high BMI. The BMI was inversely related to the ratio of forced expiratory volume in 1 second (FEV₁) to forced vital capacity (FVC)(FEV₁ %), BODE (Body mass index, airway Obstruction, Dyspnea, Exercise capacity) index and hyperinflation, had a "U" shape with dyspnea and the St. George's Respiratory Questionaire (SGRQ) score and an inverse "U" with exercise capacity. The crude mortality rate was 60%, 43%, 37%, 36% and 28% from the lowest to highest BMI groups (p<.0001). More respiratory deaths were observed in the lowest BMI group even though they had a lower number of comorbidities. Conclusions: Different BMI categories are associated with distinct clinical expressions of COPD and comorbidity patterns. The relationship between BMI and mortality in patients with COPD remains an unresolved paradox.

Extracellular matrix defects in aneurysmal Fibulin-4 mice predispose to lung emphysema

Background

In this study we set out to investigate the clinically observed relationship between chronic obstructive pulmonary disease (COPD) and aortic aneurysms. We tested the hypothesis that an inherited deficiency of connective tissue might play a role in the combined development of pulmonary emphysema and vascular disease.

Methods

We first determined the prevalence of chronic obstructive pulmonary disease in a clinical cohort of aortic aneurysms patients and arterial occlusive disease patients. Subsequently, we used a combined approach comprising pathological, functional, molecular imaging, immunological and gene expression analysis to reveal the sequence of events that culminates in pulmonary emphysema in aneurysmal Fibulin-4 deficient (Fibulin-4^R) mice.

Results

Here we show that COPD is significantly more prevalent in aneurysm patients compared to arterial occlusive disease patients, independent of smoking, other clinical risk factors and inflammation. In addition, we demonstrate that aneurysmal Fibulin-4^R/R mice display severe developmental lung emphysema, whereas Fibulin-4^+/R mice acquire alveolar breakdown with age and upon infectious stress. This vicious circle is further exacerbated by the diminished antiprotease capacity of the lungs and ultimately results in the development of pulmonary emphysema.

Conclusions

Our experimental data identify genetic susceptibility to extracellular matrix degradation and secondary inflammation as the common mechanisms in both COPD and aneurysm formation.

Influence of cardiovascular risk factors on levels of matrix metalloproteinases 2 and 9 in human abdominal aortic aneurysms

OBJECTIVE

To evaluate the influence of cardiovascular risk factors on levels of matrix metalloproteinases (MMP) 2 and 9 in human abdominal aortic aneurysms (AAA).

METHODS

Aortic samples were collected from patients who underwent AAA repair (n = 89). Patients were stratified according to the maximum transverse aorta diameter: small diameter (<55 mm), moderate diameter (55-69.9 mm) and large diameter (≥70 mm). Aortic walls were studied using real-time PCR and immunohistochemistry. MMP-2, MMP-9, α-actin, CD45, and CD68 transcript levels were determined relative to β-actin. Quantitative data were expressed as median (IQ-range).

RESULTS

No differences were found in MMP-2 expression between the patient groups, which was mainly associated with vascular smooth muscle cells (VSMC); however, MMP-9 displayed the maximum level in the moderate-diameter group, associated with infiltrating macrophages. Current smoking (CS) and renal insufficiency (RI) significantly increased local levels of MMP-2 (CS 349.5 [219.5-414.1] vs. no-CS 184.4 [100.0-320.5]; p < .008; RI 286.8 [189.6-410.8] vs. no-RI 177.3 [99.3-326.9]; p = .047). Nevertheless, after stepwise linear regression analysis only CS remained as an independent variable predicting local levels of MMP-2 (p = .002). No risk factors influenced local levels of MMP-9.

CONCLUSIONS

The results show that local levels of MMP-2, an important factor for AAA development, were increased in current smoking AAA patients. MMP-2 was mainly associated with VSMC. It is suggested that MMP-2 could contribute significantly to the increased AAA growth rate observed in current smoking patients. These findings support inclusion of smokers in screening for aneurysmal disease, and emphasize the need for more aggressive monitoring of aneurysmal disease outside the surgical range in patients who smoke at the time of diagnosis and in those who continue to smoke during follow-up.

Active smoking increases microsomal PGE2-synthase-1/PGE-receptor-4 axis in human abdominal aortic aneurysms

Background. The cyclooxygenase- (COX-) 2/microsomal PGE-synthase- (mPGES-) 1/PGE-receptor- (EP-) 4 axis could play a key role in the physiopathology of abdominal aortic aneurysm (AAA) in humans. In this study, we investigated the influence of cardiovascular risk factors on the expression of the PGE₂ pathway in human AAA. Methods. Aortic (n = 89) and plasma (n = 79) samples from patients who underwent AAA repair were collected. Patients were grouped according to risk factors. COX-isoenzymes, mPGES-1, EPs, α-actin, and CD45 and CD68 transcripts levels were quantified by QRT-PCR and plasma PGE₂ metabolites by EIA. Results. Current smoking (CS) patients compared to no-CS had significantly higher local levels of mPGES-1 (P = 0.009), EP-4 (P = 0.007), and PGE₂ metabolites plasma levels (P = 0.008). In the multiple linear regression analysis, these parameters remained significantly enhanced in CS after adding confounding factors. Results from association studies with cell type markers suggested that the increased mPGES-1/EP-4 levels were mainly associated with microvascular endothelial cells. Conclusions. This study shows that elements of the PGE₂ pathway, which play an important role in AAA development, are increased in CS. These results provide insight into the relevance of tobacco smoking in AAA development and reinforce the potential of mPGES-1 and EP-4 as targets for therapy in AAA patients.

Effect of statin drugs on thoracic aortic aneurysms

Pharmacologic interventions for thoracic aneurysms remain poorly characterized. The results of a pilot study by our group suggested improved outcomes among patients with thoracic aortic aneurysm who were taking statins. In the present study, we undertook a comprehensive analysis of a larger cohort of patients from the Database of the Aortic Institute at Yale-New Haven Hospital. A total of 1,560 patients met the inclusion criteria. The adverse events (i.e., death, dissection, or rupture) and surgery rates for patients with (n = 369, 24%) and without (n = 1,191, 76%) statin therapy were compared. We evaluated 3 anatomic components of the aorta: root, ascending and arch, and descending and thoracoabdominal aortic aneurysms. A smaller proportion of the statin group had adverse events: overall, 7% versus 15%; ascending and arch, 6% versus 15%; and descending and thoracoabdominal aortic aneurysms, 8% versus 20%. Also, a smaller proportion of statin patients required surgery: overall, 48% versus 60%; ascending and arch, 51% versus 62%; and descending and thoracoabdominal aortic aneurysms, 36% versus 59% (p <0.001 to 0.01). The protective effect of statins was seen in all segments, except the aortic root. Log-rank evaluation of the interval to an adverse event or surgery was longer among statin-treated patients (p <0.001). Logistic regression analysis found statin use, angiotensin receptor blocker use, and chronic obstructive pulmonary disease were associated with decreased adverse events, and statin use, angiotensin receptor blocker use, β-blocker therapy, and age were associated with a decreased odds of requiring surgery. Multiple logistic regression analysis found only statins were associated with a decreased odds of an adverse event and that statins, coronary artery disease, and chronic obstructive pulmonary disease were associated with a decreased odds of undergoing surgery. In conclusion, these findings provide a medicinal option for the arsenal of treatment options for patients with aneurysms of the thoracic aorta.

Chronic obstructive pulmonary disease and cardiovascular disease

Chronic obstructive pulmonary disease (COPD) is an inflammatory disease of the lung associated with progressive airflow limitation and punctuated by episodes of acute exacerbation. There is growing recognition that the inflammatory state associated with COPD is not confined to the lungs but also involves the systemic circulation and can impact nonpulmonary organs. Epidemiologic and mechanistic studies indicate that COPD is associated with a high frequency of coronary artery disease, congestive heart failure and cardiac arrhythmias, independent of shared risk factors. Possible pathways include complex interrelationships between chronic low-grade systemic inflammation and oxidative stress as well as shared risk factors such as age, cigarette smoking, and environmental pollutants. In this review, we provide an overview of the epidemiologic data linking COPD with cardiovascular disease, comment on the interrelationships among COPD, inflammation, and cardiovascular disease, and highlight diagnostic and therapeutic challenges.