Activities at Thoracic Aortic Research Center, IRCCS Policlinico San Donato.

The Thoracic Aortic Research Center (TARC) of the IRCCS Policlinico San Donato (PSD) aims to promote research on thoracic aortic diseases, to disclose the scientific knowledge and clinical experience and to develop new scientific paths within the Hospital and the aortic community, in collaboration with other national and international centres. Thoracic Aortic Research Center collaborates with many centres in both Europe (e.g. University of Utrecht, the Netherlands) and the USA (e.g. University of Michigan). This has led to multiple highly regarded publications in respected cardiovascular journals and has led to several PhD programmes resulting in doctorate degrees. Within Italy, in association with the Bioengineering School of the University of Pavia, TARC has founded the "BETA-lab" (Biomechanics for Endovascular Treatment of the Aorta laboratory), where MDs, Bioengineers, and PhD fellows conduct experimental studies using in vitro/ex vivo models of the physiologic aorta and aortic diseases. Furthermore, a database (iCardiocloud) where the medical imaging of cardiovascular patients from the PSD is structured, for in silico analysis utilizing computational fluid dynamics, and in vitro studies using also 3D printed aortic models. With the role of principal investigator or co-investigator, TARC at PSD has been participating in other several projects, including the International Registry of Acute Aortic Dissection, the International Aortic Arch Surgery Study Group, the European Registry of Endovascular Aortic Repair Complications, the ADSORB and ASSIST trials, and the GREAT registry. International collaborations have included also studies on predictors of aortic growth after dissection with the Yale University and University of Virginia, and on aortic biomarkers with the University of Tokyo.

Predicting in-hospital mortality in acute type B aortic dissection: evidence from International Registry of Acute Aortic Dissection.

BACKGROUND: The outcome of patients with acute type B aortic dissection (ABAD) is strongly related to their clinical presentation. The purpose of this study was to investigate predictors for mortality among patients presenting with ABAD and to create a predictive model to estimate individual risk of in-hospital mortality using the International Registry of Acute Aortic Dissection (IRAD). METHODS AND RESULTS: All patients with ABAD enrolled in IRAD between 1996 and 2013 were included for analysis. Multivariable logistic regression analysis was used to investigate predictors of in-hospital mortality. Significant risk factors for in-hospital death were used to develop a prediction model. A total of 1034 patients with ABAD were included for analysis (673 men; mean age, 63.5±14.0 years), with an overall in-hospital mortality of 10.6%. In multivariable analysis, the following variables at admission were independently associated with increased in-hospital mortality: increasing age (odds ratio [OR], 1.03; 95% confidence interval [CI], 1.00-1.06; P=0.044), hypotension/shock (OR, 6.43; 95% CI, 2.88-18.98; P=0.001), periaortic hematoma (OR, 3.06; 95% CI, 1.38-6.78; P=0.006), descending diameter ≥5.5 cm (OR, 6.04; 95% CI, 2.87-12.73; P<0.001), mesenteric ischemia (OR, 9.03; 95% CI, 3.49-23.38; P<0.001), acute renal failure (OR, 3.61; 95% CI, 1.68-7.75; P=0.001), and limb ischemia (OR, 3.02; 95% CI, 1.05-8.68; P=0.040). Based on these multivariable results, a reliable and simple bedside risk prediction tool was developed. CONCLUSIONS: We present a simple prediction model using variables that are independently associated with in-hospital mortality in patients with ABAD. Although it needs to be validated in an independent population, this model could be used to assist physicians in their choice of management and for informing patients and their families.

Predictors of aortic growth in uncomplicated type B aortic dissection.

BACKGROUND: Patients with uncomplicated acute type B aortic dissection (ABAD) generally can be treated with conservative medical management. However, these patients may develop aortic enlargement during follow-up, with the risk for rupture, which necessitates intervention. Several predictors have been studied in recent years to identify ABAD patients at high risk for aortic enlargement who may benefit from early surgical or endovascular intervention. This study systematically reviewed and summarized the current available literature on prognostic variables related to aortic enlargement during follow-up in uncomplicated ABAD patients. METHODS: Studies were included if they reported predictors of aortic growth in uncomplicated ABAD patients. Studies about type A aortic dissection, aortic aneurysm, intramural hematoma, or ABAD that required acute intervention were excluded. RESULTS: A total of 18 full-text articles were selected. The following predictors of aortic growth in ABAD patients were identified: age <60 years, white race, Marfan syndrome, high fibrinogen-fibrin degradation product level (≥20 µg/mL) at admission, aortic diameter ≥40 mm on initial imaging, proximal descending thoracic aorta false lumen (FL) diameter ≥22 mm, elliptic formation of the true lumen, patent FL, partially thrombosed FL, saccular formation of the FL, presence of one entry tear, large entry tear (≥10 mm) located in the proximal part of the dissection, FL located at the inner aortic curvature, fusiform dilated proximal descending aorta, and areas with ulcer-like projections. Tight heart rate control (<60 beats/min), use of calcium-channel blockers, thrombosed FL, two or more entry tears, FL located at the outer aortic curvature, and circular configuration of the true lumen were associated with negative or limited aortic growth. CONCLUSIONS: Several predictors might be used to identify those ABAD patients at high risk for aortic growth. Although conservative management remains indicated in uncomplicated ABAD, these patients might benefit from closer follow-up or early endovascular intervention.

Aortic hemodynamics after thoracic endovascular aortic repair, with particular attention to the bird-beak configuration.

PURPOSE: To quantitatively evaluate the impact of thoracic endovascular aortic repair (TEVAR) on aortic hemodynamics, focusing on the implications of a bird-beak configuration. METHODS: Pre- and postoperative CTA images from a patient treated with TEVAR for post-dissecting thoracic aortic aneurysm were used to evaluate the anatomical changes induced by the stent-graft and to generate the computational network essential for computational fluid dynamics (CFD) analysis. These analyses focused on the bird-beak configuration, flow distribution into the supra-aortic branches, and narrowing of the distal descending thoracic aorta. Three different CFD analyses (A: preoperative lumen, B: postoperative lumen, and C: postoperative lumen computed without stenosis) were compared at 3 time points during the cardiac cycle (maximum acceleration of blood flow, systolic peak, and maximum deceleration of blood flow). RESULTS: Postoperatively, disturbance of flow was reduced at the bird-beak location due to boundary conditions and change of geometry after TEVAR. Stent-graft protrusion with partial coverage of the origin of the left subclavian artery produced a disturbance of flow in this vessel. Strong velocity increase and flow disturbance were found at the aortic narrowing in the descending thoracic aorta when comparing B and C, while no effect was seen on aortic arch hemodynamics. CONCLUSION: CFD may help physicians to understand aortic hemodynamic changes after TEVAR, including the change in aortic arch geometry, the effects of a bird-beak configuration, the supra-aortic flow distribution, and the aortic true lumen dynamics. This study is the first step in establishing a computational framework that, when completed with patient-specific data, will allow us to study thoracic aortic pathologies and their endovascular management.

Acute type B aortic dissection in the absence of aortic dilatation.

BACKGROUND: Increasing aortic diameter is thought to be an important risk factor for acute type B aortic dissection (ABAD). However, some patients develop ABAD in the absence of aortic dilatation. In this report, we sought to characterize ABAD patients who presented with a descending thoracic aortic diameter <3.5 cm. METHODS: We categorized 613 ABAD patients enrolled in the International Registry of Acute Aortic Dissection from 1996 to 2009 according to the aortic diameter <3.5 cm (group 1) and ≥3.5 cm (group 2). Demographics, clinical presentation, management, and outcomes of the two groups were compared. RESULTS: Overall, 21.2% (n = 130) had an aortic diameter <3.5 cm. Patients in group 1 were younger (60.5 vs 64.0 years; P = .015) and more frequently female (50.8% vs 28.6%; P < .001). They presented more often with diabetes (10.9% vs 5.9%; P = .050), history of catheterization (17.0% vs 6.7%; P = .001), and coronary artery bypass grafting (9.7% vs 3.4%; P = .004). Marfan syndrome was equally distributed in the two groups. The overall in-hospital mortality did not differ between groups 1 and 2 (7.6% vs 10.1%; P = .39). CONCLUSIONS: About one-fifth of patients with ABAD do not present with any aortic dilatation. These patients are more frequently females and younger, when compared with patients with aortic dilatation. This report is an initial investigation to clinically characterize this cohort, and further research is needed to identify risk factors for aortic dissection in the absence of aortic dilatation.

Importance of refractory pain and hypertension in acute type B aortic dissection: insights from the International Registry of Acute Aortic Dissection (IRAD).

BACKGROUND: In patients with acute type B aortic dissection, presence of recurrent or refractory pain and/or refractory hypertension on medical therapy is sometimes used as an indication for invasive treatment. The International Registry of Acute Aortic Dissection (IRAD) was used to investigate the impact of refractory pain and/or refractory hypertension on the outcomes of acute type B aortic dissection. METHODS AND RESULTS: Three hundred sixty-five patients affected by uncomplicated acute type B aortic dissection, enrolled in IRAD from 1996 to 2004, were categorized according to risk profile into 2 groups. Patients with recurrent and/or refractory pain or refractory hypertension (group I; n=69) and patients without clinical complications at presentation (group II; n=296) were compared. "High-risk" patients with classic complications were excluded from this analysis. The overall in-hospital mortality was 6.5% and was increased in group I compared with group II (17.4% versus 4.0%; P=0.0003). The in-hospital mortality after medical management was significantly increased in group I compared with group II (35.6% versus 1.5%; P=0.0003). Mortality rates after surgical (20% versus 28%; P=0.74) or endovascular management (3.7% versus 9.1%; P=0.50) did not differ significantly between group I and group II, respectively. A multivariable logistic regression model confirmed that recurrent and/or refractory pain or refractory hypertension was a predictor of in-hospital mortality (odds ratio, 3.31; 95% confidence interval, 1.04 to 10.45; P=0.041). CONCLUSIONS: Recurrent pain and refractory hypertension appeared as clinical signs associated with increased in-hospital mortality, particularly when managed medically. These observations suggest that aortic intervention, such as via an endovascular approach, may be indicated in this intermediate-risk group.

Open surgery versus endovascular repair of ruptured thoracic aortic aneurysms.

BACKGROUND: Ruptured descending thoracic aortic aneurysm (rDTAA) is a cardiovascular catastrophe, associated with high morbidity and mortality, which can be managed either by open surgery or thoracic endovascular aortic repair (TEVAR). The purpose of this study is to retrospectively compare the mortality, stroke, and paraplegia rates after open surgery and TEVAR for the management of rDTAA. METHODS: Patients with rDTAA treated with TEVAR or open surgery between 1995 and 2010 at seven institutions were identified and included for analysis. The outcomes between both treatment groups were compared; the primary end point of the study was a composite end point of death, permanent paraplegia, and/or stroke within 30 days after the intervention. Multivariate logistic regression analysis was used to identify risk factors for the primary end point. RESULTS: A total of 161 patients with rDTAA were included, of which 92 were treated with TEVAR and 69 with open surgery. The composite outcome of death, stroke, or permanent paraplegia occurred in 36.2% of the open repair group, compared with 21.7% of the TEVAR group (odds ratio [OR], 0.49; 95% confidence interval [CI], .24-.97; P = .044). The 30-day mortality was 24.6% after open surgery compared with 17.4% after TEVAR (OR, 0.64; 95% CI, .30-1.39; P = .260). Risk factors for the composite end point of death, permanent paraplegia, and/or stroke in multivariate analysis were increasing age (OR, 1.04; 95% CI, 1.01-1.08; P = .036) and hypovolemic shock (OR, 2.47; 95% CI, 1.09-5.60; P = .030), while TEVAR was associated with a significantly lower risk of the composite end point (OR, 0.44; 95% CI, .20-.95; P = .039). The aneurysm-related survival of patients treated with open repair was 64.3% at 4 years, compared with 75.2% for patients treated with TEVAR (P = .191). CONCLUSIONS: Endovascular repair of rDTAA is associated with a lower risk of a composite of death, stroke, and paraplegia, compared with traditional open surgery. In rDTAA patients, endovascular management appears the preferred treatment when this method is feasible.

Long-term outcomes of surgical aortic fenestration for complicated acute type B aortic dissections.

INTRODUCTION: Surgical aortic fenestration has been used for treating ischemic complications of acute type B aortic dissection (ABAD). In the current endovascular era, surgical aortic fenestration may serve as an alternative for these patients after percutaneous failure. The purpose of this study is to describe our surgical suprarenal and infrarenal aortic fenestration technique, and to report the long-term outcomes of this approach in the management of complicated ABAD. METHODS: We retrospectively analyzed the in-hospital and long-term outcomes of 18 patients treated with either suprarenal (n = 10) or infrarenal surgical fenestration (n = 8) for complicated ABAD between 1988 and 2002. Suprarenal fenestration was performed through a thoracoabdominal incision in the 10th intercostal space, whereas patients treated with infrarenal fenestration underwent a midline laparotomy. A longitudinal aortotomy was performed and the true and false lumens were identified, followed by a wide resection of the intimal membrane. RESULTS: Median age was 60 years (range, 48-82 years) and 89% (n = 16) were male. The in-hospital mortality was 22% (n = 4), which included two deaths after suprarenal fenestration and two deaths after infrarenal fenestration. In the remaining patients, full visceral, renal, and lower extremity function was recovered, except for 1 patient with paraplegia at admission in which the neurologic deficit was permanent. Median follow-up of the surviving patients was 10.0 years (interquartile range, 12.5; range, 0.5-20 years). During follow-up, none of the patients developed renal or visceral ischemia, or ischemic complications to the lower extremities, and no significant dilatations of the treated aortic segments were noted. Three of 14 patients with ABAD who were discharged alive expired during the follow-up period due to causes unrelated to the surgical procedure. CONCLUSION: Surgical aortic fenestration represents an effective and durable option for treating ischemic complications of ABAD. Actually, this conservative surgical technique may serve as the alternative treatment in case of contraindications or failure of endovascular management of complicated ABAD.

[Endovascular repair of aortic abdominal aneurysms in octagenarian patients: early and midterm results]. / Trattamento endovascolare di Aneurismi dell'aorta addominale in pazienti ottantenari. Risultati a medio termine.

AIM OF THE STUDY: This article summarizes our experience in endovascular repair of abdominal aortic aneurysm in octogenarian patients. MATERIAL AND METHODS: From January 2000 to December 2005 30 patients (mean age 84 years) underwent endovascular repair of abdominal aortic aneurysm; in 28 cases a loco-regional anaesthesia has been performed. Twenty-eight bifurcated graft, one straight graft and one aorto-iliac graft have been used. RESULTS: No operative mortality or early endoleak have been observed; during the follow-up period (20 months) 7 endo-leaks (3 cases type I; 4 cases type II) have been reported; all patients with type I EL underwent endovascular repair; in two patients with type II EL we observed spontaneous regression; the other cases are still monitored in absence of sac enlargement. Four graft occlusions have been observed; one early thrombosis has been treated with surgical thrombectomy, two of the three late occlusions required other procedures. Five patients died during the follow-up period, three of them during the first year. No death has been aneurysm related. DISCUSSION: In accord with other recent studies, our analysis confirms the positive impact on intra-operative and early post-procedural mortality of the endovascular therapy for abdominal aortic aneurysm in octogenarian patients; no evidence of significative benefit on late survival has been observed. CONCLUSION: In conclusion we consider endovascular option as the best approach in octogenarian patients even if a longer follow-up is mandatory.

Role and results of surgery in acute type B aortic dissection: insights from the International Registry of Acute Aortic Dissection (IRAD).

BACKGROUND: The clinical profiles and outcomes of patients treated surgically for acute type B aortic dissection (ABAD) are often reported for those in small series or for those cared for at a single institution over a long time period, during which a continuous evolution in techniques has occurred. Accordingly, we sought to evaluate the clinical features and surgical results of patients enrolled in the International Registry of Acute Aortic Dissection by identifying primary factors that influenced surgical outcome and estimating average surgical mortality for ABAD in the current era. METHODS AND RESULTS: A comprehensive analysis of 290 clinical variables and their relation to surgical outcomes for 82 patients who required surgery for ABAD (from a population of 1256 patients; mean+/-SD age, 60.6+/-15.0 years; 82.9% male) and who were enrolled in the International Registry of Acute Aortic Dissection was performed. The overall in-hospital mortality was 29.3%. Factors associated with increased surgical mortality based on univariate analysis were preoperative coma or altered consciousness, partial thrombosis of the false lumen, evidence of periaortic hematoma on diagnostic imaging, descending aortic diameter >6 cm, right ventricle dysfunction at surgery, and shorter time from the onset of symptoms to surgery. Factors associated with favorable outcomes included radiating pain, normotension at surgery (systolic blood pressure 100 to 149 mm Hg), and reduced hypothermic circulatory arrest time. The 2 independent predictors of surgical mortality were age >70 years (odds ratio, 4.32; 95% confidence interval, 1.30 to 14.34) and preoperative shock/hypotension (odds ratio, 6.05; 95% confidence interval, 1.12 to 32.49). CONCLUSIONS: The present study provides insights into current-day clinical profiles and surgical outcomes of ABAD. Knowledge about different preoperative clinical conditions may help surgeons in making treatment decisions among these high-risk patients.

Contemporary results of surgery in acute type A aortic dissection: The International Registry of Acute Aortic Dissection experience.

BACKGROUND: Surgical mortality for acute type A aortic dissection reported in different experiences from single centers or surgeons varies from 7% to 30%. The International Registry of Acute Aortic Dissection, collecting patients from 18 referral centers worldwide, identifies a preoperative risk stratification scheme and a real average surgical mortality for acute type A aortic dissection in the current era. METHODS: A comprehensive analysis was completed of 290 clinical variables and their relationship to surgical outcomes in 526 of 1032 patients enrolled in the International Registry of Acute Aortic Dissection from 1996 through 2001. Extracted cases, categorized according to risk profile, were defined as unstable (group I) in the presence of cardiac tamponade; shock; congestive heart failure; cerebrovascular accident; stroke; coma; myocardial ischemia, infarction, or both; electrocardiograms with new Q waves or ST elevation; acute renal failure; or mesenteric ischemia-infarction at the time of the operation. Outside of an unstable condition, patients were categorized as stable (group II). RESULTS: The overall in-hospital mortality was 25.1%. Mortality in group I was 31.4% compared with 16.7% in group II ( P < .001). Independent preoperative predictors of operative mortality were history of aortic valve replacement (odds ratio = 3.12), migrating chest pain (odds ratio = 2.77), hypotension as sign of acute type A aortic dissection (odds ratio = 1.95), shock or tamponade (odds ratio = 2.69), preoperative cardiac tamponade (odds ratio = 2.22), and preoperative limb ischemia (odds ratio = 2.10). CONCLUSIONS: The International Registry of Acute Aortic Dissection experience confirms that patient selection plays an important role in determining surgical outcomes in patients with acute type A aortic dissection. Knowledge of significant risk factors for operative mortality can contribute to better management and a more defined risk assessment in patients affected by acute type A aortic dissection.

Usefulness of pulse deficit to predict in-hospital complications and mortality in patients with acute type A aortic dissection.

Vascular compromise seen with pulse deficits is common in patients with type A dissection. However, patient characteristics and in-hospital outcomes associated with pulse deficits have not been evaluated. Accordingly, we studied 513 patients (mean age 62 +/- 14 years, 65% men) with acute type A aortic dissection enrolled in the International Registry of Acute Aortic Dissection. Pulse deficits, defined as decreased or absent carotid or peripheral pulses as noted by clinicians and later confirmed by diagnostic imaging, at surgery or at autopsy were noted in 154 patients (30%). Age <70 years, male gender, neurologic deficit(s), altered mental status, and hypotension, shock, or tamponade on admission were all significantly higher in patients with than without pulse deficits. The etiology of aortic dissection, clinical symptoms, and imaging findings were similar in the 2 groups. In-hospital complications (hypotension, coma, renal failure, and limb ischemia) and mortality (41% vs 25%, p = 0.0002) were significantly higher in patients with pulse deficit. Cox proportional-hazards regression analysis identified pulse deficit as an independent predictor of 5-day in-hospital mortality (risk ratio 2.73, 95% confidence interval 1.7 to 4.4; p <0.0001). Further, overall mortality rates increased with an increasing number of pulse deficits (p for trend <0.0001). Pulse deficits are common findings in patients with type A aortic dissection and identify those at high risk of in-hospital adverse events. This simple clinical sign should direct physicians to consider a diagnosis of aortic dissection in patients with acute chest pain, and should help identify a subgroup of patients who would benefit from more aggressive strategies.

Open fenestration for complicated acute aortic B dissection.

Acute type B aortic dissection (ABAD) is a serious cardiovascular emergency in which morbidity and mortality are often related to the presence of complications at clinical presentation. Visceral, renal, and limb ischemia occur in up to 30% of patients with ABAD and are associated with higher in-hospital mortality. The aim of the open fenestration is to resolve the malperfusion by creating a single aortic lumen at the suprarenal or infrarenal level. This surgical procedure is less invasive than total aortic replacement, thus not requiring extracorporeal support and allowing preservation of the intercostal arteries, which results in decreased risk of paraplegia. Surgical aortic fenestration represents an effective and durable option for treating ischemic complications of ABAD, particularly for patients with no aortic dilatation. In the current endovascular era, this open technique serves as an alternative option in case of contraindications or failure of endovascular management of complicated ABAD.

Emergent treatment of aortic rupture in acute type B dissection.

Massive left hemothorax is a rare and dramatic complication of acute type B aortic dissection. The primary endpoint is to treat the aortic rupture, stop the bleeding and stabilize the hemodynamic status, with the aim to prevent mortality and major cardiac, cerebral, visceral and renal complications. Thoracic endovascular repair (TEVAR) is the most frequent management, although its planning, in these emergent patients, may be very difficult and sub-optimal imaging may result at post-operative examination (CT and MRI). In case of TEVAR is not the definitive treatment of the aortic disease, a second stage surgical management can be performed in elective status, in a patient with a total clinical recover. In acute and dramatic circumstances, like ruptured type B dissection, TEVAR is a valid and suitable bridge procedure to open surgery, reducing the overall risk for mortality and major complications.

Importance of dynamic aortic evaluation in planning TEVAR.

Dynamic aortic evaluation in planning thoracic endovascular aortic repair (TEVAR) is important to provide optimal stent graft sizing. Static imaging protocols do not consider normal aortic dynamics and may lead to stent graft to aorta mismatch, causing stent graft related complications, such as type I endoleak and stent graft migration. Dynamic imaging can assist in accurate stent graft selection and sizing preoperatively, and evaluate stent graft performance during follow-up. To create new imaging technologies, integration of knowledge between diverse scientific fields is essential (i.e., engineering, informatics and medicine). Different dynamic imaging modalities, such as electrocardiographic-gated computed tomography angiography (ECG-gated CTA) and four-dimensional phase-contrast MRI (4D PC-MRI), are progressively investigated and implemented into clinical practice as important instruments in preoperative planning for TEVAR. In time, further application of dynamic imaging tools for preoperative screening and follow-up after TEVAR might lead to better outcomes for patients. The advances in dynamic imaging for evaluation of the thoracic aorta using new imaging modalities and their future perspectives are addressed in this manuscript.

Biomarkers in TAA-the Holy Grail.

Thoracic aortic aneurysm (TAA) is a silent disease, often discovered at a time point that dramatic complications, as rupture and dissection, occur. For the detection of asymptomatic TAA and prevention of such complications, it is essential to have an adequate screening tool. Until now, routine laboratory blood tests have played only a minor role in the screening, diagnosis, tracking and prediction of the natural history of TAAs. However, the knowledge about biomarkers is rapidly expanding in the cardiovascular field, and there are several potential biomarkers that might be implemented into TAA clinical practice in the near future. The most important and promising markers for TAA will be discussed in this overview.

Contemporary Role of Computational Analysis in Endovascular Treatment for Thoracic Aortic Disease.

In the past decade, thoracic endovascular aortic repair (TEVAR) has become the primary treatment option in descending aneurysm and dissection. The clinical outcome of this minimally invasive technique is strictly related to an appropriate patient/stent graft selection, hemodynamic interactions, and operator skills. In this context, a quantitative assessment of the biomechanical stress induced in the aortic wall due to the stent graft may support the planning of the procedure. Different techniques of medical imaging, like computed tomography or magnetic resonance imaging, can be used to evaluate dynamics in the thoracic aorta. Such information can also be combined with dedicated patient-specific computer-based simulations, to provide a further insight into the biomechanical aspects. In clinical practice, computational analysis might show the development of aortic disease, such as the aortic wall segments which experience higher stress in places where rupture and dissection may occur. In aortic dissections, the intimal tear is usually located at the level of the sino-tubular junction and/or at the origin of the left subclavian artery. Besides, computational models may potentially be used preoperatively to predict stent graft behavior, virtually testing the optimal stent graft sizing, deployment, and conformability, in order to provide the best endovascular treatment. The present study reviews the current literature regarding the use of computational tools for TEVAR biomechanics, highlighting their potential clinical applications.

Painless Type B Aortic Dissection: Insights From the International Registry of Acute Aortic Dissection.

INTRODUCTION: The classical presentation of a patient with Type B acute aortic dissection (TBAAD) is characterized by severe chest, back, or abdominal pain, ripping or tearing in nature. However, some patients present with painless acute aortic dissection, which can lead to a delay in diagnosis and treatment. We utilized the International Registry on Acute Aortic Dissections (IRAD) database to study these patients. METHODS: We analyzed 43 painless TBAAD patients enrolled in the database between January 1996 and July 2012. The differences in presentation, diagnostics, management, and outcome were compared with patients presenting with painful TBAAD. RESULTS: Among the 1162 TBAAD patients enrolled in IRAD, 43 patients presented with painless TBAAD (3.7%). The mean age of patients with painless TBAAD was significantly higher than normal TBAAD patients (69.2 versus 63.3 years, P = 0.020). The presence of atherosclerosis (46.4% versus 30.1%, P = 0.022), diabetes (17.9% versus 7.5%; P = 0.018), and other aortic diseases (8.6% versus 2.3%, P= 0.051), such as prior aortic aneurysm (31% versus 18.8% P = 0.049) was more common in these patients. Median delay time between presentation and diagnosis was longer in painless patients (median 34.0 versus 19.0 hours; P = 0.006). Dissection of iatrogenic origin (19.5% versus 1.3%; P < 0.001) was significantly more frequent in the painless group. The in-hospital mortality was 18.6% in the painless group, compared with an in-hospital mortality of 9.9% in the control group (P = 0.063). CONCLUSION: Painless TBAAD is a relatively rare presentation (3.7%) of aortic dissection, and is often associated with a history of atherosclerosis, diabetes, prior aortic disease including aortic aneurysm, and an iatrogenic origin. We observed a trend for increased in-hospital mortality in painless TBAAD patients, which may be the result of a delay in diagnosis and management. Therefore, physicians should be aware of this relative rare presentation of TBAAD.

The role of age in complicated acute type B aortic dissection.

BACKGROUND: Complicated acute type B aortic dissection (cABAD) generally requires urgent intervention. Advanced age is a risk factor for mortality after thoracic aortic intervention, including surgery for aortic dissection. The purpose of this study was to investigate the exact impact of increasing age on the management and outcomes of cABAD. METHODS: We analyzed the outcomes of 583 patients with cABAD enrolled in the International Registry of Acute Aortic Dissection (IRAD) between 1996 and 2012. All patients with cABAD were categorized according to age by decade and management type (medical, surgical, or endovascular treatment), and outcomes were subsequently investigated in the different age groups. RESULTS: The mean age of the cohort was 63.4 ± 14.2 years, 36% of patients (n = 209) were greater than 70 years of age and 64% (n = 374) were less than 70 years. The utilization of surgery and endovascular techniques progressively decreased with patient age, while the rate of medical management significantly increased with age (p < 0.001). The in-hospital mortality rates for complicated patients younger than 70 years versus 70 years or more were 10.1% versus 30.0% for endovascular treatment (p = 0.001), 17.2% versus 34.2% for surgical treatment (p = 0.027), and 14.2% versus 32.2% for medical treatment (p = 0.001). Age 70 years or greater was a predictor of in-hospital mortality in multivariate analysis (odds ratio 2.37, 95% confidence interval: 1.23 to 4.54, p = 0.010). CONCLUSIONS: Advanced age has a dramatic impact on the management and outcomes of patients with cABAD. A nonsignificant trend toward lower mortality after endovascular management was observed, both for younger patients and for elderly patients.

Importance of false lumen thrombosis in type B aortic dissection prognosis.

BACKGROUND: Partial thrombosis of the false lumen has been reported as a significant predictor of mortality during follow-up in patients with acute type B aortic dissection. The purpose of this study was to investigate the correlation of false lumen thrombosis and aortic expansion during follow-up in patients with acute type B aortic dissection. METHODS: All medically treated patients with acute type B aortic dissection observed in 4 cardiovascular referral centers between 1998 and 2011, with admission and follow-up computed tomography or magnetic resonance imaging scans, were included. Aortic diameters of the dissected aortas were measured at 4 levels on the baseline and follow-up scans, and annual growth rates were calculated. Univariate and multivariate regression analyses were used to investigate the effect of false lumen thrombosis on aortic growth rate. RESULTS: A total of 84 patients were included, of whom 40 (47.6%) had a partially thrombosed false lumen, 7 (8.3%) had a completely thrombosed false lumen, and 37 (44.0%) had a patent false lumen. A total of 273 of the 336 (81.3%) evaluated aortic levels were dissected segments. Overall, the mean aortic diameter increased significantly at all evaluated levels (P < .001). Univariate analysis showed that annual aortic growth rates were significantly higher in those segments having a false lumen with partial thrombosis (mean, 4.25 ± 10.2) when compared with the patent group (mean, 2.10 ± 5.56; P = .035). In multivariate analysis, partial lumen thrombosis was an independent predictor of higher aortic growth (adjusted mean difference, 2.05 mm/year; 95% confidence interval, 0.10-4.01; P = .040). CONCLUSIONS: In patients with acute type B aortic dissection, aortic segments with a partially thrombosed false lumen have a significantly higher annual aortic growth rate when compared with those presenting with patent or complete thrombosis of the false lumen. Therefore, patients with partial thrombosis require more intensive follow-up and may benefit from prophylactic intervention.