Thoracic aortic aneurysms are often an accidental finding and result from a degenerative process [1]. Medical therapy involves pharmacological control of arterial hypertension and smoking cessation that slows the growth of aneurysms [2, 3]. Aortic dissection is a life-threatening condition that, in more than 50% of cases, is located in previously dilated, and not aneurysmal locations [4]. It is reported as a causative factor of over 25,000 deaths annually in the United States [5]. Guo et al. [6] reported a mean ascending aortic diameter related to acute dissection of 42.6 mm. The interaction of molecular proteins with the cellular and intercellular matrix is claimed to be related to the progression of aortic diameter [7, 8, 9].

The diagnosis of aortic pathology is based on imaging examinations, including ultrasonography followed by computed tomography (CT) or magnetic resonance angiography (MRA) [10, 11]. Ultrasound imaging can be helpful only in certain segments of the aorta, including echocardiography of the ascending aorta [12]. The rest of the aorta is only partially visible or invisible at all. Noninvasive imaging are often the first-line test that allow for the suggestion of further diagnostics including MRA or CT scans [13, 14]. Considerations regarding improved assessment of the risk of dissection and rupture based on imaging modalities are still controversial [15, 16]. MRA and CT are valuable in the evaluation of chronic dissection, while CT is dedicated to acute syndromes. The advantages of MRA include the lack of radiation and the use of gadolinium contrast media with low risk of complications, which allows for repeatable examinations and safe utility in the younger population.

Screening programs are believed to be one of the most effective options for diagnosing aortic aneurysms, as incidental findings of aortic dilatation are most common [17, 18]. The increased risk of multiple dilated segments in a single patient is well-known [19].

The aim of the study was to identify possible demographic and clinical factors that may implicate further imaging diagnostics in patients with ascending aorta dilatation.

There were 181 (93 (53%) males and 88 (47%) females) patients with a median age of 54 (41–62) years enrolled into the retrospective study. Two risk factors, most common for aneurysms’ occurrence, namely arterial hypertension and smoking, were diagnosed in 92 (51%) and 65 (36%) patients, respectively. The physically active lifestyle was postulated by 50 (28%) patients and was characterized by a median frequency of activity 3 (1–4) times a week. The demographic and clinical data were analyzed and presented in Table 1.

Data obtained from the MRA results revealed that median (Q1–Q3) values of four analyzed aortic diameters, including ascending aorta (A1) as 28 (19–48) mm, descending aorta below subclavian artery origin (A2) — 24 (21–40) mm, thoracic aorta below the diaphragm level (A3) — 21 (15–28) mm and above aortic division into common iliac arteries (A4) — 16 (12–20) mm. The Fig. 1 presents the normal and abnormal (dilatation and aneurysms) aortic diameters in A1-A4 segments.

Fig. 1.

Flow chart presenting the MRI results in A11-A4 aortic segments. MRI, magnetic resonance imaging.

The diagnostic criteria for aortic aneurysm were met in 4 (2%) patients in ascending aorta. The results are presented in Table 2. The A2–A4 diameters were analyzed in relation to the diameters of A1. The risk for A2–A4 dilatation was evaluated by uni- and multivariable analysis in patients with an A1 diameter above the normal range. The analysis was performed for each of A2–A4 diameters.

3.4 Receiver Operator Curve Analysis

3.4.1 ROC Curve Analysis for Descending Aorta Dilatation Related to Ascending Aorta Dilatation

ROC analysis for aortic A2 segments dilatation related to the diameter of the ascending aorta (segment A1) revealed the area under the curve (AUC = 0.933, p 0.001) yielded sensitivity of 90% and specificity of 91.23% as presented in Fig. 2a. ROC analysis revealed predictive values for abdominal aorta dilatation (segment A3) related to the diameter of the ascending aorta (segment A1) (AUC = 0.856, p 0.001) yielding sensitivity of 68.75% and specificity of 84.56% as presented in Fig. 2b.

Fig. 2.

Receiver operator curve analysis for non-ascending aorta diameter relation to ascending aorta. (a) Receiver operator curve analysis for aortic A2 segments dilatation related to the diameter of the ascending aorta (segment A1). (b) Receiver operator curve revealed predictive values for abdominal aorta dilatation (segment A3) related to the diameter of the ascending aorta (segment A1). AUC, area under the curve.

3.4.2 Receiver Operator Curve Analysis for Aortic Dilatation Related to Age

ROC analysis revealed predictive values for thoracic aorta dilatation (segment A2) related to the age, representing the area under the curve (AUC = 0.659, p 0.001) with an optimal cut off value over 49 years, yielding sensitivity of 87.50% and specificity of 42.95% as presented in Fig. 3a. ROC analysis revealed predictive values for abdominal aorta dilatation (segment A3) related to the age, presenting area under the curve (AUC = 0.765, p 0.001) with an optimal cut off value above 54 years, yielding a sensitivity of 100% and a specificity of 53.80% as presented in Fig. 3b.

Fig. 3.

Receiver operator curve analysis relating age to aortic dilatation. (a) Receiver operator curve analysis revealed predictive values for thoracic aorta dilatation (segment A2) related to the age. (b) Receiver operator curve analysis revealed predictive values for abdominal aorta dilatation (segment A3) related to the age. AUC, area under the curve.

3.4.3 ROC Curve Analysis for Descending Aorta Dilatation in the Multivariable Analysis

ROC curve analysis for aortic enlargement in A2 and A3 segments related to the multifactorial predictive score constructed based on age over 50 years, ascending aorta dilatation over 36 mm and co-existence of coronary artery disease revealed the area under the curve (AUC = 0.720, p 0.001), yielding a sensitivity of 90.62% and a specificity of 42.95% as presented in Fig. 4.

Fig. 4.

Receiver operator curve analysis presenting multifactorial predictive score for aortic dilatation in A2 and A3 segments. AUC, area under the curve.

According to the results of the study, patients with ascending aorta dilatation who are over 49 years of age and with concomitant coronary artery disease (CAD) are more predisposed to dilatation of thoracic aorta dilatation and those over 54 years of age are more predisposed to abdominal aorta dilatation. The predictive value of these three parameters for thoracic and abdominal aorta dilatation was presented in our logarithmic regression predictive score and may be applied in clinical practice for screening tests.

In western countries, the prevalence of aortic aneurysms is reported in 1–2% of women and 1–9% of men [26]. Screening for aneurysms is fundamental to avoid acute aortic syndromes, which are related to high death rates [4].

In the thoracic segments of the aorta, 60% of aneurysms are reported in the ascending part [27]. Arterial hypertension, family history, smoking habits, and male sex are reported as well-known risk factors for aortic aneurysm development [28]. In patients presenting with increased cardiovascular risks, the US Preventive Services Task Force has endorsed screening ultrasound tests for abdominal aneurysms [29]. In the meta-analysis by Kobeissi et al. [30] hypertension increases the risk of developing abdominal aortic aneurysm (AAA) by 66%. Vascular wall changes, impaired endothelial cell function and aortic elasticity are included in the pathogenesis of arterial hypertension and aortic aneurysm, which may suggest that mechanisms are closely related [31]. The effect of smoking on the risk of aneurysm occurred higher than on the risk of coronary artery disease or peripheral vascular disease [32]. Data on the influence of diabetes are conflicting, since several studies did not prove a negative effect of hyperglycemia on aneurysm occurrence and even suggested a beneficial aspect of diabetes [33, 34]. This controversial phenomenon was explained by collagen and elastin alterations within the wall of the aorta leading to inhibited secretion of metalloproteinases and prevention of excessive proteolysis, improvement of wall stability and reduced rate of expansion; moreover, lifestyle changes in diabetic patients introduced to reduce blood glycaemia were supposed as beneficial against aortic aneurysm progression [35]. Interestingly, diabetes was not revealed as associated with either thoracic or abdominal aortic dilatation. On the contrary, obesity was associated with aortic aneurysm development, concerning the release of adipokines and induction of aortic inflammation, which may lead to vessel weakening and subsequent wall abnormalities [35]. Moreover, co-morbidities and risk factors in obese patients are similar to the aforementioned ones.

Our presented analysis indicates that patients with ascending aorta dilatation, which can be easily assessed in the screening echocardiography, should be considered for further examination of dilatation of the other aortic segments, particularly in the coexistence of coronary artery disease.

Our study confirms previous reports including Ballegaard et al. [36] and Hernesniemi et al. [37] analyses, which claimed the consistently high prevalence of coronary artery disease and coexistence of abdominal aneurysms in the current population. However, an Italian group [38] did not confirm a relationship between abdominal aneurysms and atherosclerotic changes in other arterial districts. Kim et al. [39] proved that the prevalence of carotid artery disease is significantly higher in patients with abdominal aneurysms than in patients with thoracic aneurysms. We analyzed patients without a known aortic aneurysm and showed that even aortic dilatation not reaching the criteria of aneurysm may be associated with the co-existence of coronary artery disease. The novelty of our analysis is supported by the relevance of the finding that coronary disease coexistence is associated with not only abdominal aortic dilatation presented by segment A3 diameters, but also thoracic aorta diameter dilatation. In our analysis, diameter was also relevant for thoracic aorta dilatation and was presented as a novel valuable factor for descending aorta dilatation.

Our analysis did not focus on aortic aneurysms but an increased aortic diameter should promote scrutiny and close inspection for those patients who are at risk for aneurysm development. In our opinion, finding that the dilatation of ascending aorta does not fit the criteria of an aneurysm may unduly reassure the safety of the patient and therefore delay further diagnostics. In fact, dilatation of the ascending aorta, particularly in patients over 50 years of age and concomitant coronary artery should warrant broadening of the diagnostics to evaluate diameters of the descending aorta.

The analysis was based on MRA results of patients with non-vascular diseases, and the criteria for aortic dilatation were based on previous reports including 36 mm for ascending aorta [40], 30 mm for descending aorta below subclavian artery origin [41], 24 mm for descending aorta below diaphragm [42], and 20 mm for aorta above division into common iliac arteries [43]. Importantly, our study group was composed of patients with no previous diagnosis of aortic dilatation, in whom the exam was planned for other reasons, while our results indicate that the incidental findings may justify the need for screening tests.

The early recognition of aortic diameter enlargement should lead to the intensification of antihypertensive pharmacotherapy, which is believed to influence the progression of aortic dilatation [1, 2]. The body mass index (BMI) reduction combined with appropriate pharmacotherapy directed on cardiovascular risk modification can help reduce the aortic dilatation rate [44]. Aortic aneurysm is characterized by active processes, including local inflammatory activation [6, 8, 45]. Endothelial dysfunction as an early pathologic event in aneurysm formation is claimed to contribute to either oxidative stress or inflammatory degeneration of the arterial wall [46]. Endothelial dysfunction is accompanied by the inability of aortic wall smooth muscle cells to generate force through the elastin-contractile units in response to pulsatile blood flow [7, 47]. Current pharmacotherapy includes a wide range of medications, including antihypertensive and antidiabetic [48, 49]. The potential of anti-inflammatory agents and antibiotic therapy requires large, randomized studies to be regarded as a therapeutic option, as the effective pharmacotherapy of aortic dilatation is still lacking [50].

In the majority of people, aortic aneurysms are incidental findings [51], which indicates the need for proper screening, as the mortality rate in acute aortic syndromes is still high [52]. In routine screening ultrasound tests, such as echocardiography, the ascending aorta is visualized [53, 54] and its potential dilatation may be regarded as a potential indicator for further evaluation.

The novelty of our study is based on identifying the relationship between ascending aorta and abdominal and thoracic aorta dilatation. Until now, a relationship between aneurysms of ascending and abdominal segments had only been postulated in the Gallego-Colon et al. study [55].

The study was designed based on CMR examinations in a population without a previous diagnosis of aortic dilatation. The screening tests should consider not only the MRA, but also computed tomography angiography due to its wider availability. However, the MRA can not only reveal the dilatation of the aorta but is also used to determine pulse wave velocities, wall shear stress, intramural hematoma, thrombus in dissected false lumen, penetrating aortic ulcer or bicuspid aortic valve [56].

The results of our analysis, identify that both imaging and clinical parameters reflect the relationship between the ascending aorta and the thoracic and abdominal aorta dilatation. Patients with ascending aorta dilatation and co-existence of coronary artery disease, particularly those over the age of 49 or 54 years, respectively, are more prone to thoracic and abdominal aorta dilatation.

The data supporting their findings may be obtained from the corresponding authors after reasonable explanation of requirement by e-mail contact for 3 years following the publications.

TU, AOW, ZK, MJ, AT and KJF designed the research study. MM, PR, MS, JRT, AK, BK, MP, AT, MJ and ZK analyzed the data. TU, AOW, KJF, JRT, AT, MJ and ZK wrote and edited the manuscript. All authors contributed to editorial changes in the manuscript. All authors read and approved the final manuscript. All authors have participated sufficiently in the work and agreed to be accountable for all aspects of the work.

The study was performed according to the principles of Good Clinical Practice and the Declaration of Helsinki and was approved by the Local Ethics Committee of the Medical University of Poznan (approval number: 749/20 on 4 November 2020). All patients gave their informed consent for the inclusion to the study.

Not applicable.

This research received no external funding.

The authors declare no conflict of interest.