Descriptive statistics are presented for demographic and baseline variables as absolute and relative frequencies. Categorical variables are presented as frequencies (percentages). Continuous variables are presented as means (standard deviation) if normally distributed and medians (interquartile range) if not.

To identify variables that could influence in-hospital mortality, univariate comparisons of baseline variables were performed using Pearson's chi-square and Fisher's exact tests, the latter when the event rates were low (<10 events). The same statistical analysis was used to study the relation between in-hospital mortality and TBAD stage at treatment (acute vs. chronic), type of complication (MPS vs. aneurysmal degeneration/rupture vs. elective), and treatment modalities used (open vs. endovascular). In addition, variables affecting in-hospital mortality were included in a multivariate logistic regression model. Statistical significance was set at p<0.05. Analyses were performed using Stata version 14.0 for Mac (Stata Corp® 2015, Stata Statistical Software: Release 14. College Station, TX: StataCorp LP).

A total of 100 patients were admitted to our department for TBAD between January 2003 and March 2019. The mean age at admission was 60 years (34–84 years) and most of the cohort were men (83%). The prevalence of risk factors was as follows: hypertension (77%), smoking (32%), dyslipidemia (24%), and chronic kidney disease (23%). Concomitant aortic diseases were recorded in 12 patients: seven with Marfan syndrome, three with Loeys-Dietz syndrome and two with aortic coarctation (Table 1).

As described above, the study was divided into two time periods: 2003–2010 (n=40) and 2011–2019 (n=60).

In the first period, 19 out of 40 (47.5%) patients were operated and underwent open repair, 14 in the acute/subacute phase and five in the chronic phase. No endovascular procedures were performed during this period.

After 2011, 45 out of 60 (75%) were operated, 16 in the acute phase and 29 in the chronic phase. In the acute phase eight patients underwent open repair and eight underwent endovascular procedures. In the chronic phase, 15 (51.7%) patients underwent endovascular procedures and 14 (48.3%) underwent open repair (Figures 1 and 2).

Figure 1.

Rate of operated patients versus total number of patients hospitalized for type B aortic dissection. AD: aortic dissection.

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Figure 2.

Open versus endovascular surgery in the two study periods.

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Furthermore, if the second period (2011–2019) is divided in two, a gradual increase in the frequency of endovascular interventions is evident (Figure 3), and in the more recent period (2015–2019) an endoluminal strategy was adopted as a first approach for treatment of TBAD.

Figure 3.

Open versus endovascular surgery when the second study period is divided into two.

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Of the overall population, 59 patients were admitted in the acute/subacute phases of dissection.

Thirty patients (50.8%) had complicated TBAD, 80% (24 out of 30) with MPS and 20% (six out of 30) with acute aortic dilation. Of these, two patients (6.7%) died before any intervention. The other 29 patients (49.2%) were uncomplicated cases and were managed with optimal medical treatment.

Within the subgroup of patients with MPS there were 12 visceral ischemia events, eight of renal ischemia and 11 of lower limb ischemia in a total of 24 patients. It should be noted that some patients had more than one ischemic territory on admission. As mentioned above, all complicated TBAD patients underwent intervention, 71.4% (n=20) by open surgery and 28.6% (n=8) by endovascular treatment. All endovascular interventions were performed after 2015 (Table 2).

Most of the 41 patients admitted in the chronic phase (82.9%; n=34) underwent surgical treatment. Four patients (9.8%) were admitted as an emergency with ruptured aneurysms and died before any intervention. Three patients (7.3%) were considered unsuitable for surgery and were treated with optimal medical therapy.

Thirty-two patients (94.1%) were operated for post-dissection aneurysmal degeneration and in the other two patients (5.9%) the indication was refractory pain and renovascular hypertension. As in the acute phase, most patients (55.9%; n=19) were treated by open surgery, and the other 15 patients (44.1%) underwent endovascular repair. All endovascular treatments were performed after 2013 (Table 3).

During the second period of the study, we treated more TBAD patients than in the first period. This seems to be related to more frequent referral of chronic patients in 2011–2019 (33.3% in 2003–2010 vs. 64.4% in 2011–2019), as the number of acute/subacute patients was similar in both periods.

This may be explained by greater awareness among the medical community concerning aortic disease and the effectiveness of adequate and timely interventions leading to more frequent referral of patients for treatment, particularly following the introduction of less invasive endovascular procedures with fenestrated and branched endografts for post-dissection thoracoabdominal aneurysms.

The data also revealed a paradigm shift in treatment between the two study periods, with more patients being treated by endovascular intervention. This may be explained by two factors.

The first reflects new treatment concepts emerging in recent years with the introduction and evolution of endoluminal strategies for early dissections.2–9,14,15 We started treating aortic dissections with endovascular technology in 2013, within the framework of a program for endovascular repair of thoracic and thoracoabdominal aneurysms, which expanded significantly from 2015 onward. The second factor is the progressive adoption of endovascular techniques to manage thoracoabdominal aneurysms and post-dissection aneurysms, expanding their applicability to patient groups previously considered unsuitable for open repair.15

The treatment of complicated TBAD has evolved in the last decade, with TEVAR becoming the first-line technique to manage MPS by covering the entry tear and redirecting blood flow to the true lumen. Adjuvant procedures such as the PETTICOAT and STABILISE techniques may be used in association with TEVAR when adequate expansion of the true lumen is not achieved with TEVAR.4–9,16

Regarding uncomplicated TBAD, the most accepted policy has been optimal medical therapy, with hypertension control being of paramount importance. However, recent data have challenged this concept, showing five-year survival of 50–70% and four-year delayed expansion of the false lumen in 20–50% of medically treated uncomplicated TBAD cases.10–14,17 Therefore, in some patients, a more liberal use of TEVAR as a prophylactic intervention could play a part in improving long-term aortic remodeling14,16–20 and preventing late aneurysmal degeneration. To avoid overtreatment, several studies have aimed to identify clinical and imaging prognostic variables related to aortic enlargement during follow-up in uncomplicated acute TBAD patients. Clinical predictors include young age (<60 years), white race, high heart rate (≥60 bpm) and Marfan syndrome, while imaging predictors include absence of complete thrombosis of the false lumen, increased aortic diameter (≥40 mm), false lumen diameter in the proximal descending aorta ≥22 mm, large entry tear (≥10 mm) located in the proximal part of the dissection, false lumen and entry tear located in the inner aortic curvature, and longitudinal extent and elliptical configuration of the false lumen.21,22

If more liberal use of TEVAR had been adopted earlier, the mortality discrepancy recorded in the chronic phase of our study, mainly related to post-dissection ruptured aneurysms, might have been avoided.

The proper timing for the intervention is also controversial. As demonstrated in the VIRTUE registry, TEVAR is expected to obtain better results when performed at an early stage of the disease, when the aorta has greater plasticity and therefore a greater propensity for positive remodeling.17 This should be balanced against a higher risk of iatrogenic aortic rupture in the early stages of the dissection.

Our study showed that the practice patterns in our hospital were in line with modern developments, with endovascular strategies used in the majority of patients from 2015, leading to an endovascular-first approach for TBAD.

The modern management of TBAD also requires the overall involvement of the institution in providing the structural and logistical support that is crucial for the appropriate treatment of these patients. An integrated approach that assesses each patient within the framework of the Department of Heart and Vessels, close cooperation with the cardiac surgery team and mobilization of different resources from hematology to neuromonitoring, are important steps for this integrated approach and are the pillars of the concept of an ‘aortic center’ that can provide multidisciplinary patient-tailored treatment to continuously improve our results. Hybrid operating rooms are a major requirement for modern and successful management of complex aortic disease, including aortic dissection, and are essential in our institution, as endovascular techniques are often complemented with open procedures for access, combined revascularization approaches and the treatment of life-threatening complications. Additionally, new logistical needs have emerged, including ensuring the permanent in-house availability of a large range and stock of endovascular materials. Finally, these patients can only be appropriately managed if cardiovascular-oriented intensive care units are available perioperatively.

One of the strengths of our study is that it provides an assessment of practice in a single center with severely diseased patients with aortic dissection who underwent intervention over a long period. This enabled us to assess changes in practice and confirmed a paradigm shift in the management of TBAD, with the incorporation of new developments and adoption of the state of the art for the management of aortic dissection and complex aortic aneurysms.

The limitations of our study are its relatively small and heterogeneous sample, incomplete stratification of medical therapy and insufficient data on late outcomes including re-interventions and late aortic events. There is a need for better standardization in the selection and availability of stent grafts according to individual patient and aortic morphology.

However, the study provides information on our institutional practice, representing an exercise of the scientific accountability that is essential in modern clinical practice.