Acute type B aortic dissection complicated by visceral ischemia

Twenty-five years of observations from the International Registry of Acute Aortic Dissection (IRAD) and its impact on the cardiovascular scientific community

OBJECTIVE

The International Registry of Acute Aortic Dissection (IRAD) celebrated its 25th anniversary in January 2021. This study evaluated IRAD's role in promoting the understanding and management of acute aortic dissection (AD) over these years.

METHODS

IRAD studies were identified, analyzed, and ranked according to their citations per year (c/y) to determine the most-cited IRAD studies and topics. A systematic search of the literature identified cardiovascular guidelines on the diagnosis and management of acute AD. Consequently, IRAD's presence and impact were quantified using these documents.

RESULTS

Ninety-seven IRAD studies were identified, of which 82 obtained more than 10 cumulative citations. The median c/y index was 7.33 (25th-75th percentile, 4.01-16.65). Forty-two studies had a greater than median c/y index and were considered most impactful. Of these studies, most investigated both type A and type B AD (n = 17, 40.5%) and short-term outcomes (n = 26, 61.9%). Nineteen guideline documents were identified from 26 cardiovascular societies located in Northern America, Europe, and Japan. Sixty-nine IRAD studies were cited by these guidelines, including 38 of the 42 most-impactful IRAD studies. Among them, partial thrombosis of the false lumen as a predictor of postdischarge mortality and aortic diameters as a predictor of type A occurrence were determined as most-impactful specific IRAD topics by their c/y index.

CONCLUSIONS

IRAD has had and continues to have an important role in providing observations, credible knowledge, and research questions to improve the outcomes of patients with acute AD.

Evaluation of Thoracic Endovascular Repair for the Treatment of Type B Aortic Dissection Complicated by Malperfusion

Objectives: This study aims to investigate the efficacy of thoracic endovascular aortic repair (TEVAR) for type B aortic dissection (TBAD) complicated by malperfusion. Methods: This retrospective study included patients who underwent TEVAR for the treatment of TBAD complicated by malperfusion from June 1998 to June 2022 in four institutions. In addition to the common outcomes, including short- and medium-term mortality and morbidity, the preservation of each organ was investigated. Results: A total of 23 patients were included in this analysis. The 30-day mortality was 4% (1/23) of the patients. The overall survival rate was 87% at 1 year. The preservation rate of each organ was 33% (4/12) for the visceral organs, 85% (17/20) for the kidneys, and 100% (18/18) for the legs. Fisher's exact test showed a significant difference in the preservation rate between the viscera and the other organs (P = 0.018 vs. kidneys, P = 0.0025 vs. legs). It was shown that the survival rate of patients with visceral malperfusion was significantly lower than that of patients with non-visceral malperfusion (P = 0.006). Conclusion: In terms of mortality, TEVAR showed satisfactory results. The preservation of visceral organs was still challenging even with TEVAR and adjunctive measures.

Midterm Outcome of Branch Vessel Stenting for Superior Mesenteric Artery Malperfusion Complicating with Acute Aortic Dissection

Purpose

To investigate the midterm stent patency and patient prognosis after stenting for superior mesenteric artery malperfusion complicating with acute aortic dissection.

Material and Methods

Thirteen patients who underwent branch vessel stenting for superior mesenteric artery malperfusion between 2011 and 2021 in six institutions were retrospectively reviewed. By comparing pre- and postoperative computed tomography scans in the same plane, the length of the stent implanted in the superior mesenteric artery and the stent-to-vessel diameter ratio were measured. The technical and clinical success of stenting, midterm patient prognosis, and stent patency were evaluated.

Results

Superior mesenteric artery stenting was technically successful in 12 patients (92.3%). The mean length of the stents implanted in the superior mesenteric artery was 61.3 ± 39.4 mm (range, 14-127 mm). The mean proximal and distal stent-to-vessel diameter ratios were 1.02 ± 0.16 and 1.30 ± 0.42, respectively. A weak correlation was found between the length of the stents implanted in the superior mesenteric artery and the distal stent-to-vessel diameter ratio (R2 = 0.34). Two major complications occurred, one of which resulted in death within 30 days, and 12 (92.3%) were clinically successful. Of these 12 patients, no recurrent intestinal ischemia occurred during the follow-up duration (mean, 45.2 months). Partial occlusion of the stent distal edge without intestinal ischemia was observed in one patient (distal stent-to-vessel diameter ratio = 2.33) 42 months after stenting. The overall survival rate and primary stent patency rate were 84.6% and 91.7%, respectively.

Conclusions

Midterm stent patency and survival after superior mesenteric artery stenting for malperfusion were acceptable.

Nursing Home Admission and Home Care Initiation After Acute Aortic Dissection: A Nationwide Registry-Based Cohort Study

Background

Little is known about long-term outcomes beyond survival following acute aortic dissection. The aim of this research was to evaluate rates of home care initiation and nursing home admission during the first year after discharge and to assess factors associated with these needs.

Methods

All patients in Denmark with a first-time diagnosis of acute aortic dissection type A or B between 2006 and 2015 were identified using national registries. Patients discharged alive without nursing home or home care use before aortic dissection were included, along with age-matched and sex-matched population controls without aortic dissection (at a ratio of 1:5). Cause-specific multivariable Cox regression was used to derive adjusted hazard ratios.

Results

The study population comprised 1093 patients and 5465 control individuals with a median (IQR) age of 64 (55-71) years; 70.6% were men. During their hospital stay, 2.7% of patients were registered with a first-time diagnosis of stroke, 7.1% with heart failure, and 2.2% with acute kidney failure; 5.9% of patients needed first-time dialysis. During the first year after discharge, 0.8% of patients who had had aortic dissection were admitted to a nursing home, 7.8% started home care, and 5.9% died. Among controls, these rates were 0.2%, 1.2%, and 1.2%, respectively. Patients who had had aortic dissection had significantly increased risk of initiating home care (hazard ratio, 7.47 [95% CI, 5.38-18.37]; P < .001) and of being admitted to a nursing home (hazard ratio, 4.28 [95% CI, 1.73-10.59]; P = .001). Initiation of home care and nursing home admission were related to advanced age, female sex, preexisting comorbidities, in-hospital complications, and conservative management of type A aortic dissection.

Conclusion

Only a small proportion of patients who survived an aortic dissection needed home care or nursing home admission after hospital discharge.

Natural history of visceral branch artery dissections and the influence of concurrent aortic dissection on overall and intervention-free survival

OBJECTIVE

Visceral branch artery dissection (VBAD) is uncommon and may occur with or without an associated aortic dissection (AD). We hypothesized that isolated VBAD would have a more benign clinical course than those with concurrent AD and compared survival outcomes stratified based on aortic involvement.

METHODS

VBAD over a 5-year period were identified using International Classification of Diseases codes. Data related to patient demographics, comorbid conditions, clinical presentation, management (including procedural interventions), and survival were obtained from medical records. Anatomic imaging studies were reviewed to characterize anatomy, including the presence or absence of concurrent AD. Overall survival and intervention-free survival were evaluated using Kaplan-Meier and Cox proportional hazards models.

RESULTS

A total of 299 VBAD were identified, 174 of which were isolated VBAD and 125 were associated with concurrent AD. Seventy-one percent of patients were men, 77% were White, and 85% were non-Hispanic. The mean age was 61.1 ± 14.4 years. The mean follow-up was 53.2 ± 50.0 months. The estimated overall survival was 88.2% and the estimated overall intervention-free survival was 55.6% at 12 months. Isolated VBAD had better overall survival than those with concurrent AD (69.2% vs 32.4%; P < .001). Concurrent AD was also associated with inferior intervention-free survival (57.5% vs 7.3%; P < .001). Acute presentation was associated with decreased intervention-free survival (86.1% vs 13.4%; P < .001). Acute presentation was also associated with decreased overall survival in patients with isolated VBAD (60.8% vs 80.0% at 180 months; P < .001) and inferior intervention-free survival (48.4% vs 69.5% at 180 months; P < .001) in the subgroup of patients with isolated VBAD. Multivariable Cox models identified that age (hazard ratio [HR]: 1.05, standard deviation [SD]: 0.02; P = .001) was associated with inferior survival and renal dissections (HR: 3.08, SD: 0.99; P = .001) or mesenteric and renal dissections (HR: 3.39, SD: 1.44; P = .004) were associated with inferior intervention-free survival.

CONCLUSIONS

Isolated VBAD has superior overall and intervention-free survival to those associated with concurrent AD. The absence vs presence of aortic involvement is useful for risk stratification and may support tailored approaches to the frequency of imaging surveillance.

One-Year Results of a Low-Profile Endograft in Acute, Complicated Type B Aortic Dissection

BACKGROUND

The safety and effectiveness of the RelayPro endograft (Terumo Aortic) was assessed for the treatment of acute, complicated type B aortic dissection (TBAD).

METHODS

A prospective pivotal trial analyzed a primary end point of all-cause mortality at 30 days. Secondary end points included technical success, major adverse events (disabling stroke, renal failure, and paraplegia/paralysis), endoleaks, patency, rupture, device integrity, false lumen perfusion, reinterventions, aortic expansion, and migration evaluated to 5 years.

RESULTS

The study involved 22 United States centers and enrolled 56 patients (mean age, 59.5 ± 11.4 years) from 2017 to 2021; of whom, 73.2% were men and 53.6% were African American. TBAD was complicated by malperfusion of the kidneys (51.8%), lower extremities (35.7%), and viscera (33.9%), and rupture (10.7%). Dissection extended proximally to zones 1/2 (14.3%) and zone 3 (78.6%) and distally to the iliac arteries (67.3%). Most procedures were percutaneous (85.5%). Technical success was 100%. Median hospitalization was 7 days (interquartile range, 5-12 days). All-cause mortality at 30 days was 1.8% (1 of 56; upper 95% CI, 8.2%; P < .0001). Seven major adverse events occurred in 6 patients (10.7%), consisting of paraplegia (n = 3), paraparesis (n = 2), disabling stroke (n = 1), and renal failure (n = 1). All paraplegia/paraparesis resolved with lumbar drainage. Kaplan-Meier analysis estimated a freedom from major adverse events of 89.1% at each interval from 30 days to 3 years. There was 1 endoleak (Type Ia), 2 retrograde dissections, and aortic diameter growth occurred in 2. There has been no rupture, fistula, component separation, patency loss, stenosis, kinking, twisting, bird beak, loss of device integrity, or fracture.

CONCLUSIONS

RelayPro is safe and effective in acute, complicated TBAD. Follow-up is ongoing to evaluate longer-term outcomes and durability.

Clinical Outcomes and Factors Associated With Aortic Shrinkage After Thoracic Endovascular Aortic Repair for Aneurysmal Chronic Aortic Dissection

PURPOSE

The effectiveness of thoracic endovascular aortic repair (TEVAR) for chronic aortic dissection (AD) with aneurysmal degeneration remains controversial. We retrospectively investigated clinical outcomes and assessed predictors of aortic shrinkage after TEVAR for chronic aneurysmal AD.

MATERIALS AND METHODS

Between January 2010 and December 2021, 70 patients with double-barrel-type chronic AD were enrolled. Major intimal tears in thoracic aorta were covered by stent graft. Early and late clinical outcomes, and diameter change of downstream aorta during follow-up period were reviewed. Subsequently, factors associated with aortic shrinkage were assessed by logistic regression analysis.

RESULTS

Mean age was 63 (interquartile range [IQR]: 54-68) years, 54 (80%) men, median duration from AD onset was 4 (IQR: 1-10) years, and maximum aortic diameter was 53 (IQR: 49-58) mm. Supra-aortic debranching procedure was required in 57 (81%) patients. Early aorta-related death occurred in 2 (3%) patients. Both stroke and spinal cord ischemia occurred in 1 (2%) patient. Five-year freedom rates from aorta-related death and reintervention were 96% and 51%, respectively. Sixty-four patients underwent follow-up computed tomography (84%) 1 year after TEVAR, with 33 (52%) achieving aortic shrinkage. In multivariable analysis, duration from AD onset (per year) (odds ratio [OR]: 0.82, 0.70-0.97; p=0.017) and maximum aortic-diameter ratio between aortic arch and descending aorta (per 0.1) (morphologic index; OR: 1.34, 1.04-1.74; p=0.023) were independent aortic shrinkage predictors.

CONCLUSIONS

Thoracic endovascular aortic repair for chronic AD with aneurysmal degeneration achieved satisfactory survival outcomes, but with a considerable reintervention rate. Duration from AD onset and preoperative aortic morphology could affect post-TEVAR aortic shrinkage. Earlier intervention could lead to better aortic shrinkage.

CLINICAL IMPACT

Thoracic endovascular aortic repair for chronic aortic dissection with aneurysmal degeneration showed low incidence of early and late aorta-related death. By contrast, aortic shrinkage rate was low with high incidence of reintervention to the residual downstream aorta. According to the assessment of preoperative variables, chronicity and aortic morphology could predict postoperative aortic shrinkage.

Aortic dissection: results of the invasive treatment in France between 2012 and 2018 according to the French national database

BACKGROUND

To evaluate results of the invasive repair in the management of acute aortic dissection (AoD) in France.

METHODS

Patients admitted to hospital with acute AoD from 2012 to 2018 were identified. Patient demographics, severity score at admission, treatment strategy and in-hospital mortality were described. For patients undergoing intervention, perioperative complications rate was reported. A secondary analysis evaluating patients' outcome as regards of the annual caseload per center was conducted.

RESULTS

Overall, 14,706 patients with acute AoD were identified (male 64%, mean age 67, median modified Elixhauser score 5). The overall incidence increased during the study period (from 3.8 in 2012 to 4.4/100,000 in 2018) associated with a North-South gradient (respectively 3.6 vs. 4.7/100,000) and a winter peak; 45.5% (N.=6697) of patients received medical treatment alone. Among those with invasive repair, 6276 (78.3%) were defined as type A AoD (TAAD), whereas type B AoD (TBAD) accounted for 1733 patients (21.7%), of whom 1632 (94%) had TEVAR and 101 (6%) had other arterial procedures; 30-day mortality was respectively 18.9% in TAAD and 9.5% for TBAD. In high-volume centers (i.e. >20 AoD/year), a lower 3-month mortality of 22.3% was noted compared to 31.4% in the low-volume centres (P<0.001); 47% of patients reported ≥1 early major complication. TEVAR exhibited less complication (P<0.001) compared to other arterial reconstructions in TBAD.

CONCLUSIONS

The incidence of acute AoD increased in France over the period of the study and was associated with stable postoperative early mortality. Early postoperative mortality is significantly reduced in high-volume centers.

The anesthesiologist's perspective on emergency aortic surgery: Preoperative optimization, intraoperative management, and postoperative surveillance

The management of emergencies related to the aorta requires a multidisciplinary approach involving various health care professionals. Despite technological advancements in treatment methods, the risks and mortality rates associated with surgery remain high. In the emergency department, definitive diagnosis is usually obtained through computed tomography angiography, and management focuses on controlling blood pressure and treating symptoms to prevent further deterioration. Preoperative resuscitation is the main focus, followed by intraoperative management aimed at stabilizing the patient's hemodynamics, controlling bleeding, and protecting vital organs. After the operation, factors such as organ protection, transfusion management, pain control, and overall patient care must be taken into account. Endovascular techniques are becoming more common in surgical treatment, but they also present new challenges in terms of complications and outcomes. It is recommended that patients with suspected ruptured abdominal aortic aneurysms be transferred to facilities with both open and endovascular treatment options and a track record of successful outcomes to ensure the best patient care and long-term results. To achieve optimal patient outcomes, close collaboration and regular case discussions between health care professionals are necessary, as well as participation in educational programs to promote a culture of teamwork and continuous improvement.

A Computational Study of Dynamic Obstruction in Type B Aortic Dissection

A serious complication in aortic dissection is dynamic obstruction of the true lumen (TL). Dynamic obstruction results in malperfusion, a blockage of blood flow to a vital organ. Clinical data reveal that increases in central blood pressure promote dynamic obstruction. However, the mechanisms by which high pressures result in TL collapse are underexplored and poorly understood. Here, we developed a computational model to investigate biomechanical and hemodynamical factors involved in Dynamic obstruction. We hypothesize that relatively small pressure gradient between TL and false lumen (FL) are sufficient to displace the flap and induce obstruction. An idealized fluid-structure interaction model of type B aortic dissection was created. Simulations were performed under mean cardiac output while inducing dynamic changes in blood pressure by altering FL outflow resistance. As FL resistance increased, central aortic pressure increased from 95.7 to 115.3 mmHg. Concurrent with blood pressure increase, flap motion was observed, resulting in TL collapse, consistent with clinical findings. The maximum pressure gradient between TL and FL over the course of the dynamic obstruction was 4.5 mmHg, consistent with our hypothesis. Furthermore, the final stage of dynamic obstruction was very sudden in nature, occurring over a short time (<1 s) in our simulation, consistent with the clinical understanding of this dramatic event. Simulations also revealed sudden drops in flow and pressure in the TL in response to the flap motion, consistent with first stages of malperfusion. To our knowledge, this study represents the first computational analysis of potential mechanisms driving dynamic obstruction in aortic dissection.

Surgical and endovascular repair for type B aortic dissections with mesenteric malperfusion syndrome: A systematic review of in-hospital mortality

OBJECTIVES

Mesenteric malperfusion is a feared complication of aortic dissection, with high mortality. The purpose of this study was to systematically review in-hospital mortality (IHM) of endovascular and surgical management of acute and chronic Stanford type B aortic dissections (TBAD) complicated by mesenteric malperfusion (MesMP).

METHODS

A systematic search of English language articles was conducted in relevant databases. Data on patient demographics, procedure details, and survival outcomes were collected. Reports were classified by type of intervention performed. Studies that failed to report patient-level outcomes based on specific intervention performed or IHM were excluded. Retrospective chart review of previously published data from a single institution was also performed to further identify cases of TBAD that were managed endovascularly. The Fisher exact test was performed to determine statistical significance.

RESULTS

In total, 37 articles were suitable for inclusion in this systematic review, which yielded 149 patients with a median age 55.0 years (interquartile range, 46.5-65 years) and 79% being male. Overall, in-hospital mortality was 12.8% (19/149) and was similar between endovascular and open surgical interventions (13% vs 11%, P = .99). Among endovascular strategies, IHM was greater, although not statistically significant in the thoracic endovascular aortic repair group compared with the fenestration/stenting without thoracic endovascular aortic repair group (24% vs 11%, P = .15).

CONCLUSIONS

Multiple strategies exist for the management of TBAD with MesMP; however, a majority of cases were managed endovascularly. Despite advances in therapies, mortality remains high at 13%.

Hemodynamic Study of Stanford Type B Aortic Dissection Based on Ex Vivo Porcine Aorta Models

Background:

In this study, we aimed to evaluate hemodynamic influence of the dissected aortic system via various ex vivo type B aortic dissection (AD) models.

Methods:

Twenty-four raw porcine aortas were harvested and randomly divided into 4 groups to create various aortic models. Model A was the control group, while models B to D indicated the AD group, where models B and C presented a proximal primary entry with the false lumen (FL) lengths of 15 and 20 cm, respectively, and model D presented a 20 cm FL with a proximal primary entry and a distal reentry. All the aortic models were connected to a mock circulation loop to attain the realistic flow and pressure status. The flow distribution rate (FDR) of the aortic branches was calculated. Doppler ultrasound was applied to visualize the AD structure and to attain the velocity of flow in both the true and false lumens. Several sections of the AD were stained with hematoxylin and eosin for histologic evaluation after the experiment.

Results:

This study demonstrated that higher pressures were found for the AD group compared with the control group. The mean systolic pressures at the inlet of models A to D were 113.34±0.81, 120.58±0.52, 117.76±0.82, and 115.87±0.42 mm Hg, respectively. The FDRs of the celiac artery in models A to D were 8.65%, 8.32%±0.15%, 7.87%±0.13%, and 8.03%±0.21%, respectively. By ultrasound visualization, the velocity of the flow at the entry to the FL in the AD group ranged in 10 to 92 cm/s. The dissection flap presented pulsatile movement, especially in the models B and C which contained 1 primary entry without distal reentries. Histological examinations indicated that AD was located between the intimal and medial layers.

Conclusions:

Our ex vivo models demonstrated that the configuration of the dissected aorta influenced the pressure distribution. Moreover, the dissection flap affected the FDR of the aortic branches that possibly inducing malperfusion syndrome.

Quantification of visceral perfusion and impact of femoral cannulation: in vitro model of aortic dissection

OBJECTIVES

We aimed to simulate blood flow at an aortic dissection in an in vitro vascular model and assess the impact of the cannulation method on visceral perfusion.

METHODS

An aortic-dissection model with an acrylic aortic wall and silicone intimal flap was developed to study visceral perfusion under various cannulation conditions. The primary tear was placed in the proximal descending aorta and the re-entry site in the left common iliac artery. A cardiovascular pump was used to reproduce a normal pulsatile aortic flow and a steady cannulation flow. Axillary and axillary plus femoral cannulation were compared at flow rates of 3-7 l/min. Haemodynamics were analysed by using four-dimensional flow magnetic resonance imaging.

RESULTS

Axillary cannulation (AC) was found to collapse the true lumen at the coeliac and superior mesentery arteries, while combined axillary and femoral cannulation did not change the size of the true lumen. Combined axillary and femoral cannulation resulted in a larger visceral flow than did AC alone. When axillary plus femoral cannulation was used, the visceral flow increased by 125% at 3 l/min, by 89% at 4 l/min, by 67% at 5 L/min, by 98% at 6 l/min and by 101% at 7 l/min, respectively, compared to those with the AC only.

CONCLUSIONS

Our model was useful to understanding the haemodynamics in aortic dissection. In this specific condition, we confirmed that the intimal flap motion can partially block blood flow to the coeliac and superior mesenteric arteries and that additional femoral cannulation can increase visceral perfusion.

Risk factors and treatment outcomes for type B aortic dissection with malperfusion requiring adjunctive procedures after thoracic endovascular aortic repair

OBJECTIVE

To investigate the risk factors for unrelieved malperfusion after thoracic endovascular aortic repair (TEVAR) alone.

METHODS

From January 2009 to December 2019, 86 patients with type B aortic dissection-induced malperfusion were enrolled. Demographics and clinical and imaging data, as well as treatment outcomes, were collected and compared between patients with malperfusion relieved by TEVAR alone (TR) or by TEVAR with adjunctive procedures (TA).

RESULTS

Among the 86 enrolled patients, 17 (19.8%) had malperfusion requiring TA. Patients in the TA group were more likely to suffer lower limb ischemia (P = .004), present with severe ischemia (P = .003), and have more than one end-organ ischemia (P = .015). There were more involved vessels classified as the mixed type in the TA group (P = .002). Mixed ischemia was the only independent risk factor for malperfusion requiring TA (odds ratio, 4.7; 95% confidence interval [CI], 1.3-17.2; P = .017). The ischemia-related in-hospital mortality rate of the TA group was significantly higher than that of the TR group (P = .023), and malperfusion requiring TA was the only risk factor in the multivariate logistic regression (odds ratio, 14.6; 95% CI, 1.4-150.5; P = .025). The 5-year overall cumulative survival rates were 82.4% (95% CI, 66.1%-100.0%) in the TA group and 89.5% (95% CI, 81.6%-98.1%) in the TR group (P = .294).

CONCLUSIONS

Type B aortic dissection-induced malperfusion requiring TA was associated with a higher ischemia-related in-hospital mortality rate. Mixed obstruction was an independent risk factor for unrelieved malperfusion after TEVAR alone, and early identification of potential patients requiring TA could thereby be achieved. Reasonable treatment strategies could contribute to the successful management of malperfusion requiring TA.

Endovascular therapies for Type B Aortic Dissection

Aortic dissection is a life-threatening condition resulting from a tear in the intimal layer of the aorta, requiring emergent diagnosis and prompt multi-disciplinary management strategy for best patient outcomes. While type A dissection involving ascending aorta is best managed surgically due to high early mortality, type B aortic dissection (TBAD) involving descending aorta generally has better outcomes with conservative management and medical therapy as primary strategy is favored. However, there has been a recent paradigm shift in management of TBAD due to late aneurysmal degeneration of TBAD increasing morbidity and mortality at longer-term. Late surgical intervention can be prevented by early endovascular intervention when combined with optimal medical therapy. In this narrative review, we explore available literature on different endovascular therapies for TBAD in different populations of patients.

A Mock Circulation Loop for In Vitro Hemodynamic Evaluation of Aorta: Application in Aortic Dissection

PURPOSE

Aortic dissection (AD) is a catastrophic disease with complex hemodynamic conditions, however, understandings regarding its perfusion characteristics were not sufficient. In this study, a mock circulation loop (MCL) that integrated the Windkessel element and patient-specific silicone aortic phantoms was proposed to reproduce the aortic flow environment in vitro.

MATERIALS AND METHODS

Patient-specific normal and dissected aortic phantoms with 12 branching vessels were established and embedded into this MCL. Velocities for aortic branches based on 20 healthy volunteers were regarded as the standardized data for flow division. By altering boundary conditions, the proposed MCL could mimic normal resting and left-sided heart failure (LHF) conditions. Flow rates and pressure status of the aortic branches could be quantified by separate sensors.

RESULTS

In normal resting condition, the simulated heart rate and systemic flow rate were 60 bpm and 4.85 L/minute, respectively. For the LHF condition, the systolic and diastolic blood pressures were 75.94±0.77 mmHg and 57.65±0.35 mmHg, respectively. By tuning the vascular compliance and peripheral resistance, the flow distribution ratio (FDR) of each aortic branch was validated by the standardized data in the normal aortic phantom (mean difference 2.4%±1.70%). By comparing between the normal and dissected aortic models under resting condition, our results indicated that the AD model presented higher systolic (117.82±0.60 vs 108.75±2.26 mmHg) and diastolic (72.38±0.58 vs 70.46±2.33 mmHg) pressures, the time-average velocity in the true lumen (TL; 36.95 cm/s) was higher than that in the false lumen (FL; 22.95 cm/s), and the blood transport direction between the TL and FL varied in different re-entries.

CONCLUSIONS

The proposed MCL could be applied as a research tool for in vitro hemodynamic analysis of the aorta diseases under various physical conditions.

Quantitative analysis of renal blood flow during thoracic endovascular aortic repair in type B aortic dissection using syngo iFlow

Background

Currently, the thoracic endovascular aortic repair is the recommended clinical treatment for type B aortic dissections. Unfortunately, malperfusion or ischemia of the kidneys is a major complication of type B aortic dissections. Despite this, few studies have focused on the effects of thoracic endovascular aortic repair on blood flow in renal arteries and parenchyma. This current investigation used novel real-time imaging software to quantitatively analyze the hemodynamic changes in renal artery blood flow and perfusion before and after stent graft placement.

Methods

A total of 51 patients with type B aortic dissection undergoing thoracic endovascular aortic repair between April 2017 and September 2019 were retrospectively recruited. The pre-and post-procedural digital subtraction angiography images were converted into color-coded maps using syngo iFlow for quantitative comparison. Time-intensity curves and related parameters, including the average peak ratio (avg.Pr), average delayed time to peak (avg.dTTP), and average area under the curve ratio (avg.AUCr) of the renal arteries and renal cortex were obtained and analyzed. Wilcoxon signed-rank test was used to compare iFlow parameters before and after endovascular repair. Spearman correlation analyses were performed to study iFlow parameters and renal function parameters and the estimated glomerular filtration rate (eGFR) and blood urea nitrogen (BUN).

Results

A total of 102 images including 51 pre-operative and 51 post-operative image datasets were successfully post-processed. Following endovascular repair, syngo iFlow showed a significant 33.0% increase in avg.Pr (P<0.001) and a significant 35.1% increase in avg.AUCr (P<0.001) in the renal artery. Additionally, there was a significant 12.2% decrease in the avg.dTTP (P=0.001), a significant 24.5% increase in avg.Pr (P=0.004), and a significant 38.3% increase in avg.AUCr (P=0.009) in the renal cortex. Spearman correlation analysis showed that after endovascular repair there was a significant correlation between the avg.Pr of the renal artery and eGFR (r=0.30; P=0.0349), the avg.Pr of the renal cortex and eGFR (r=0.30; P=0.0300), and the avg. AUCr of the renal cortex and BUN (r=0.31; P=0.0289).

Conclusions

syngo iFlow provided a novel quantitative method for evaluating renal hemodynamic changes in patients with type B aortic dissection undergoing endovascular treatment. Time-intensity curve parameters may facilitate the intraprocedural evaluation of renal blood flow and perfusion to complement the color-coded map.

Prognostic dynamic nomogram integrated with metabolic acidosis for in-hospital mortality and organ malperfusion in acute type B aortic dissection patients undergoing thoracic endovascular aortic repair

BACKGROUND

Organ malperfusion is a lethal complication in acute type B aortic dissection (ATBAD). The aim of present study is to develop a nomogram integrated with metabolic acidosis to predict in-hospital mortality and organ malperfusion in patients with ATBAD undergoing thoracic endovascular aortic repair (TEVAR).

METHODS

The nomogram was derived from a retrospectively study of 286 ATBAD patients who underwent TEVAR from 2010 to 2017 at a single medical center. Model performance was evaluated from discrimination and calibration capacities, as well as clinical effectiveness. The results were validated using a prospective study on 77 patients from 2018 to 2019 at the same center.

RESULTS

In the multivariate analysis of the derivation cohort, the independent predictors of in-hospital mortality and organ malperfusion identified were base excess, maximum aortic diameter ≥ 5.5 cm, renal dysfunction, D-dimer level ≥ 5.44 μg/mL and albumin amount ≤ 30 g/L. The penalized model was internally validated by bootstrapping and showed excellent discriminatory (bias-corrected c-statistic, 0.85) and calibration capacities (Hosmer-Lemeshow P value, 0.471; Brier Score, 0.072; Calibration intercept, - 0.02; Slope, 0.98). After being applied to the external validation cohort, the model yielded a c-statistic of 0.86 and Brier Score of 0.097. The model had high negative predictive values (0.93-0.94) and moderate positive predictive values (0.60-0.71) for in-hospital mortality and organ malperfusion in both cohorts.

CONCLUSIONS

A predictive nomogram combined with base excess has been established that can be used to identify high risk ATBAD patients of developing in-hospital mortality or organ malperfusion when undergoing TEVAR.

Morphologic characteristics and endovascular management of acute type B dissection patients with superior mesenteric artery involvement

OBJECTIVE

Despite its association with static mesenteric malperfusion, the morphologic characteristics and optimal management of acute type B aortic dissection (ABAD) with superior mesenteric artery (SMA) involvement are poorly understood. We studied the associated risk factors and reported the outcomes of endovascular treatment.

METHODS

From May 2016 to May 2018, we examined 212 consecutive patients with ABAD in our center. Those with SMA involvement (SMAI) were included in the present study and divided into those with and without mesenteric malperfusion (MMP) according to the clinical findings. After thoracic endovascular aortic repair (TEVAR) with or without SMA revascularization, we compared the clinical data, imaging results, and outcomes for those with and without MMP.

RESULTS

Computed tomography angiography confirmed 44 cases of SMAI: 12 (27.3%) with MMP and 32 (72.7%) without MMP. The patients with MMP had presented more frequently with lower extremity malperfusion (33.3% vs 3.1%; P = .023) than had those without MMP, with an odds ratio of 14.15 (P = .047). Multivariate analysis showed that patients with a low true lumen (TL)/false lumen (FL) diameter ratio of the SMA (TL/FL-SMA <1) had a greater risk of developing MMP than those with a high TL/FL-SMA ratio of >1 (odds ratio, 8.49; 95% confidence interval, 1.24-58.26; P = .029). SMA TL thrombosis was a significant predictor of the requirement for additional SMA revascularization after TEVAR among patients with MMP (P = .045). During a mean 10-month follow-up period, complete FL thrombosis in the SMA was seen in 11 patients (25%; 33.3% with MMP vs 21.9% without MMP; P = .43). The overall mortality rate was 6.82% (16.7% in the MMP group and 3.1% in the non-MMP group; P = .09).

CONCLUSIONS

In the present study, limb ischemia and the TL/FL-SMA ratio were two independent predictors for the development of MMP in patients with ABAD and SMAI. We found that TEVAR can be safely performed for these patients, and SMA TL thrombosis predicted for the need for SMA revascularization.

[Treatment of a patient with acute thoracoabdominal aortic dissection complicated by haemothorax]

Total left-sided haemothorax is a rare and severe complication of acute DeBakey type III aortic dissection. The primary aim of treatment is immediate arrest of haemorrhage and stabilization of the haemodynamic status of the patient. Endovascular isolation of the ruptured thoracic portion of the aorta using a stent graft (TEVAR) has recently become the 'gold standard' in treatment of acute, rupture-complicated aortic dissections of this localization. Described in the article is a clinical case report concerning successful endovascular treatment of a seriously ill patient with dissection of the thoracoabdominal portion of the aorta, rupture and massive haemorrhage into the left pleural cavity. The patient underwent endoprosthetic repair of the descending aorta in the setting of a hybrid operating room under local anaesthesia, followed by drainage of the left pleural cavity. The postoperative period was uneventful with no complications. The patient was discharged in a satisfactory condition on day 10 after the emergency surgical intervention. An important advantage of TEVAR for aortic ruptures is a minimally invasive nature of the procedure, consisting in no need to perform either sternothoracotomy or to connect a heart-lung machine, thus decreasing surgical wound, reducing the risk of perioperative life-threatening haemorrhage, and contributing to early activation of the patient.

Usefulness of Transesophageal Echocardiography in the Evaluation of Celiac Trunk and Superior Mesenteric Artery Involvement in Acute Aortic Dissection

Mesenteric ischemia is a serious complication of acute aortic dissection (AAD), and its early diagnosis is vital for prognosis and appropriate treatment indication. Arteries affected by this complication are the celiac trunk and superior mesenteric artery, and their evaluation is usually based on computed tomographic angiography. Transesophageal echocardiography is also a useful technique for diagnosing AAD and is essential in monitoring surgical or endovascular treatment when computed tomographic angiography is not available. However, the usefulness of transesophageal echocardiography for evaluating celiac trunk and superior mesenteric artery involvement and mesenteric ischemia mechanisms in AAD is not well established. Real-time information on mesenteric malperfusion is needed at the bedside, in primary care facilities, and in the operating room to achieve prompt diagnosis and better therapeutic management. The aims of this review are to assess the role of TEE to diagnose celiac trunk and superior mesenteric artery involvement in AAD, determine the mechanisms that can cause flow obstruction in patients with mesenteric ischemia, and analyze possible implications in the treatment of this complication.

Open stented elephant trunk for complicated Stanford type B aortic dissection: a single-center experience

Background

Open stented elephant trunk (SET) or SET with left subclavian artery (LSCA) to left common carotid artery (LCCA) bypass is proven to a potentially alternative treatment for complicated Stanford type B aortic dissection (TBAD). In the current study, we reported our experience with ten consecutive TBAD patients who underwent open SET.

Methods

Patients with complicated TBAD underwent open SET from May 2016 to November 2018 in our institution were included. Patients’ clinical data were obtained from the electronic medical record system, and long-term clinical outcomes were collected by telephone interviews or outpatient interviews.

Results

A total of ten patients with nine males and one female were included, and the average age was 47.3 (31–65) years. Increased D-dimer and fibrinogen degradation products were observed in all patients at admission, and two patients had renal insufficiency. The average postoperative mechanical ventilation time, length of stay in intensive care unit, and postoperative hospital length of stay were 46.9 (6.7–151.2) hours, 7.7 (4–17) days, and 15.7 (10–26) days. No postoperative death occurred. Acute kidney injury and other complications were observed, and they were recovered well when discharge. In long-term follow-up, computed tomography angiography indicated that aortas were completely well remodeled, and blood supply of the brachiocephalic trunks was normal without anastomotic complications. All patients lived well.

Conclusion

SET or SET with subclavian artery correction shows satisfactory clinical outcomes, and it could be considered as an alternative treatment. Well-designed, large-scale studies with long-term follow-up are still needed.

Acute Aortic Occlusion and Its Sequelae: Metabolic, Pathologic Etiology, and Management

Acute occlusion of the abdominal aorta is a catastrophic occurrence that results in high risk of limb loss and death. The etiology has historically been either acute embolism obstructing the aortic bifurcation in 8% to 75% of patients, or thrombosis of existing aorta-iliac occlusive disease in 35% to 84% of patients. Other etiologies include thrombosis of either a previously placed endograft or aortic graft or acute dissection. The most common symptoms are severe pain in almost 100% of patients or lower extremity paralysis/paresis in up to 80% of patients. Evaluation in the past was by angiography, but presently, computed tomography angiography is the preferred imaging study. Treatment is dependent on the etiology and includes embolectomy, aorta femoral bypass, axillary femoral bypass, and endovascular techniques. The aim of intervention is to restore flow in the shortest time period. Mortality rates vary widely from 17% to 52%, amputation occurs in up to 30% of patients. Paraplegia can occur in 40% of patients, renal insufficiency in 40% to 70%, and visceral ischemia in 6% to 14%. Both mortality and morbidity are affected by the duration of ischemia and the local and systemic complications of reperfusion injury. Complications of acute aortic occlusion can be reduced by a more prompt diagnosis, rapid intervention, and a more rapid and complete reestablishment of perfusion.

Society for Vascular Surgery (SVS) and Society of Thoracic Surgeons (STS) Reporting Standards for Type B Aortic Dissections

This Society for Vascular Surgery/Society of Thoracic Surgeons (SVS/STS) document illustrates and defines the overall nomenclature associated with type B aortic dissection. The contents describe a new classification system for practical use and reporting that includes the aortic arch. Chronicity of aortic dissection is also defined along with nomenclature in patients with prior aortic repair and other aortic pathologic processes, such as intramural hematoma and penetrating atherosclerotic ulcer. Complicated vs uncomplicated dissections are clearly defined with a new high-risk grouping that will undoubtedly grow in reporting and controversy. Follow-up criteria are also discussed with nomenclature for false lumen status in addition to measurement criteria and definitions of aortic remodeling. Overall, the document provides a facile framework of language that will allow more granular discussions and reporting of aortic dissection in the future.

Endovascular Therapy for Nonischemic vs Ischemic Complicated Acute Type B Aortic Dissection

Purpose: To report a single-center experience with thoracic endovascular aortic repair (TEVAR) for complicated acute type B aortic dissection (cATBAD) comparing patients with vs without end-organ ischemia. Materials and Methods: Between November 2010 and December 2017, 64 patients (mean age 64.8±12.5 years; 49 men) underwent TEVAR for cATBAD. Patients were grouped into 2 cohorts: nonischemic (39, 61%) patients with unrelenting pain, early progressive aortic dilatation, uncontrolled hypertension, or rupture, and ischemic (25, 39%) patients with visceral, renal, lower extremity, or spinal cord hypoperfusion. Results: Mean time from diagnosis to treatment was 7.5 days (range 1–32) in the nonischemic group vs 2.3 days (range 1–14) days in the ischemic group (p=0.007). Fourteen (56%) of 25 ischemic cATBAD patients had stents implanted in the renovascular branch vessels, while 4 (16%) patients had stents implanted in the iliac arteries. When branch vessel cannulation failed, fenestrations were made in the intimal flap to improve perfusion of the involved branch (n=5). In the nonischemic group, 3 arteries were stented owing to atherosclerotic stenosis. Technical success was achieved in 62 (97%) of 64 patients; despite stenting, 2 patients had low renal artery perfusion on final angiography. There were no statistically significant differences in early or late outcomes between the nonischemic vs ischemic cATBAD patients. Six (9%) patients died within 30 days: 2 (5%) in the nonischemic group vs 4 (16%) in the ischemic group. Major complications (1 stroke, 2 cases of paraplegia, 1 retrograde type A dissection, and 1 case of bowel ischemia) occurred only in the nonischemic group. The mean follow-up was 28 months. Late endoleaks were observed in 3 (8%) nonischemic patients and 1 (4%) ischemic patient. Reinterventions were required in 7 (18%) nonischemic patients and 4 (16%) ischemic patients. Conclusion: TEVAR is an effective and safe method of treating cATBAD. Early intervention in ischemic cATBAD may have played a significant role in the lack of significant difference between ischemic and nonischemic cATBAD outcomes. Direct visceral reperfusion through branch vessel stenting during TEVAR may be crucial in achieving good outcomes in ischemic cATBAD.

Retrograde stenting of the superior mesenteric artery is the procedure of choice for dissection of the aorta with mesenteric compromise

Acute mesenteric ischemia secondary to aortic dissection in type A and type B is a true vascular surgical emergency. Presentation can be subtle or dramatic, and time to revascularization is limited before irreversible changes occur. The literature recognizes the catastrophic consequences of acute superior mesenteric artery occlusion and the need for urgent revascularization, often before central aortic repair in type A. There is no optimal revascularization technique described in this scenario. We present a case of type A aortic dissection with acute dynamic and static superior mesenteric artery occlusion and describe treatment that resulted in successful salvage of the bowel and the patient's life.

Management of acute type B aortic dissection with malperfusion via endovascular fenestration/stenting

OBJECTIVE

The study objective was to evaluate the management of malperfusion in acute type B aortic dissection with endovascular fenestration/stenting.

METHODS

From 1996 to 2018, 182 patients with an acute type B aortic dissection underwent fenestration/stenting for suspected malperfusion based on imaging, clinical manifestations, and laboratory findings. Data were obtained from medical record review and the National Death Index database.

RESULTS

The median age of patients was 55 years. Signs of malperfusion included abdominal pain (61%), lower-extremity weakness (27%), nonpalpable lower-extremity pulses (24%), and abnormal lactate, creatinine, liver enzymes, and creatine kinase levels. Confirmed hemodynamically significant malperfusion affected the spinal cord (2.7%), celiac (24%), superior mesenteric (40%), renal (51%), and iliofemoral (43%) arterial distributions. Of the 182 patients, 99 (54%) underwent aortic fenestration/stenting, 108 (59%) had 1 or multi-branch vessel fenestration/stenting, 5 (2.7%) had concomitant thoracic endovascular aortic repair, 17 (9.3%) had additional thrombolysis or thromboembolectomy, and 48 (26%) received no intervention. After fenestration/stenting, 24 patients (13%) required additional procedures for necrotic bowel or limb and 9 patients (4.9%) had subsequent aortic repair (thoracic endovascular aortic repair, open repair) before discharge. The new-onset paraplegia was 0%. The in-hospital mortality was 7.7% over 20+ years and 0% in the last 8 years. The 5- and 10-year survivals were 72% and 49%, respectively. The significant risk factors for late mortality were age and acute paralysis (hazard ratio, 3.5; both P < .0001). Given death as a competing factor, the 5- and 10-year cumulative incidence of reintervention was 21% and 31% for distal aortic pathology, respectively.

CONCLUSIONS

Patients with acute type B aortic dissection with malperfusion can be managed with endovascular fenestration/stenting with excellent short- and long-term outcomes. This approach is particularly helpful to patients with static malperfusion of aortic branch vessels.

The current role of echocardiography in acute aortic syndrome

Acute aortic syndrome (AAS) comprises a range of interrelated conditions caused by disruption of the medial layer of the aortic wall, including aortic dissection, intramural haematoma and penetrating aortic ulcer. Since mortality from AAS is high, a prompt and accurate diagnosis using imaging techniques is paramount. Both transthoracic (TTE) and transoesophageal echocardiography (TEE) are useful in the diagnosis of AAS. TTE should be the first imaging technique to evaluate patients with thoracic pain in the emergency room. Should AAS be suspected, contrast administration is recommended when images are not definitive. TEE allows high-quality images in thoracic aorta. The main drawback of this technique is that it is semi-invasive and the presence of a blind area that limits visualisation of the distal ascending aorta near. TEE identifies the location and size of the entry tear, secondary communications, true lumen compression and the dynamic flow pattern of false lumen. Although computed tomography (CT) is the most used imaging technique in the diagnosis of AAS, echocardiography offers complementary information relevant for its management. The best imaging strategy for appropriately diagnosing and assessing AAS is to combine CT, mainly ECG-gated contrast-enhanced CT, and TTE. Currently, TEE tends to be carried out in the operating theatre immediately before surgical or endovascular therapy and in monitoring their results. The aims of this review are to establish the current role of echocardiography in the diagnosis and management of AAS based on its advantages and limitations.

Insights From the International Registry of Acute Aortic Dissection: A 20-Year Experience of Collaborative Clinical Research

Acute aortic dissection (AAD) is a life-threatening condition associated with high morbidity and mortality rates, and it remains a challenge to diagnose and treat. The International Registry of Acute Aortic Dissection was established in 1996 with the mission to raise awareness of this condition and provide insights to guide diagnosis and treatment. Since then, >7300 cases have been included from >51 sites in 12 countries. Although presenting symptoms and physical findings have not changed significantly over this period, the use of computed tomography in the diagnosis has increased, and more patients are managed with interventional procedures: surgery in type A AAD and endovascular therapy in type B AAD; with these changes in care, there has been a significant decrease in overall in-hospital mortality in type A AAD but not in type B AAD. Herein, we summarized the key lessons learned from this international registry of patients with AAD over the past 20 years.

Distal Extended Endovascular Aortic Repair PETTICOAT: A Modified Technique to Improve False Lumen Remodeling in Acute Type B Aortic Dissection

BACKGROUND

Data from the literature suggest that in patients with acute, complicated type B aortic dissection (cTBAD), initial successful treatment with thoracic endovascular aneurysm repair (TEVAR) is not necessarily associated with favorable remodeling of the dissected aorta during follow-up, and long-term results indicate that TEVAR failed to completely suppress false lumen patency. Sealing of all relevant distal reentries, infrarenal and/or iliac, seems to be the key issue to induce total false lumen thrombosis in abdominal aorta as well as the iliac arteries, especially in complicated patients presenting with malperfusion or complete true lumen collapse.

MATERIALS AND METHODS

Of the 34 consecutive patients diagnosed with cTBAD at our hospital from January 2015 to April 2018, 30 had complicated dissections receiving endovascular treatment according to the standard Provisional ExTension To Induce COmplete ATtachment (PETTICOAT) technique and were excluded from this study, whereas 4 patients with radiologic evidence of multiple reentry tears at detached lumbar arteries and iliac bifurcation with complete true lumen collapse and clinical evidence of malperfusion were treated with a modified PETTICOAT technique with distal extension of the aortic stent, balloon expansion of the stented true lumen, and use of the AFX bifurcated endograft system to preserve the natural aortic bifurcation and provide complete distal sealing of reentry tears.

RESULTS

Primary technical success was achieved in all patients. No postoperative deaths were observed, but 1 patient experienced an hemorrhagic shock on the second postoperative day. No patient suffered postoperative stroke, paraplegia, paraparesis, or acute renal failure.

CONCLUSIONS

Using an abdominal aortic bifurcated endograft with PETTICOAT to treat acute cTBAD seems to be a feasible approach in high-risk patients to improve aortic remodeling. The AFX bifurcated endograft system meets the requirements of anatomical fixation and sealing of distal tears.

Preoperative proteinuria and clinical outcomes in type B aortic dissection after thoracic endovascular aortic repair

Background

Proteinuria is a marker of poor outcomes in several diseases; however, few studies have been conducted to explore the prognostic value of proteinuria, assessed by urine dipstick test, for clinical outcomes in patients with type B acute aortic dissection (TBAD) undergoing thoracic endovascular aortic repair (TEVAR).

Methods

Consecutive patients with TBAD undergoing TEVAR were enrolled from January 2010 to July 2015. Proteinuria was defined as trace or higher, according to the results of urine dipstick testing. Associations among proteinuria and adverse events were evaluated.

Results

In total, 671 patients with a mean age of 44±15 years were included in the analysis. Proteinuria was detected in 281 patients (41.9%) before TEVAR. Multivariate logistic regression analysis showed that C-reactive protein and impaired renal function were independent predictors for proteinuria. During hospitalization, 21 patients died. In-hospital mortality was higher in patients with proteinuria (1.5% vs. 5.3%, p=0.005). After a median 3.4 years follow up, the post-TEVAR death rate was 10.4% (85 patients were lost to follow-up). The long-term cumulative mortality was significantly higher in patients with proteinuria (17.2% vs. 8.2%, log-rank=11.36, p=0.001). Multivariate Cox survival modeling indicated that proteinuria was significantly associated with long-term death, after adjustment for potential confounding risk factors (HR=1.92, p=0.012).

Conclusions

Pre-TEVAR proteinuria was identified as a prognostic marker in patients with TBAD and has potential for application as a convenient and simple risk assessment method before TEVAR.

Does Interhospital Transfer Influence the Outcomes of Patients Receiving Surgery for Acute Type A Aortic Dissection? Type A Aortic Dissection: Is Transfer Hazardous or Beneficial?

Introduction

The progression of acute type A aortic dissection may cause immediate death, such that, in the event of its diagnosis, emergency surgery is indicated. Relatedly, an interhospital transfer may prolong the time from diagnosis to surgery. This study therefore investigated how interhospital transfers impact surgical outcomes for acute type A aortic dissection.

Materials and Methods

After excluding those patients who received deferred surgery for acute type A aortic dissection, 112 patients who received emergency surgery for the condition at our hospital from January 2011 to January 2018 were enrolled. These patients were divided into two groups, one consisting of the patients who were sent directly to our emergency department (group 1) and the other consisting of the patients who were transferred from another hospital after first being diagnosed with type A aortic dissection (group 2). The collected data included the patient demographics, clinical characteristics, operative findings and methods, postoperative outcomes, latest follow-up time, and most recent status.

Results

There were 59 patients in group 1 and 53 patients in group 2. Univariate analysis revealed that group 1 had significantly more patients with a previous stroke (p = 0.007). Moreover, the average length of time from receiving a computed tomography (CT) scan to entering the operating room (OR) was shorter for the group 1 patients (p < 0.001). However, except for the incidence of postoperative acute kidney injury (14.5% versus 33.3%, p = 0.024), there was no statistical difference between the groups in terms of the operative findings and outcomes, such as hypotension before cardiopulmonary bypass, hemopericardium, other complications, and survival rate. Multivariate analysis showed that the independent predictors of hospital mortality included age > 61.5 years (p = 0.017), respiratory rate upon admission > 18.5 breaths/minute (p = 0.046), and total bypass time > 265.6 minutes (p = 0.015). For the patients who survived to discharge, log-rank analysis demonstrated similar cumulative survival rates for the two groups (p = 0.62). Further multivariate analysis showed that the risk of death after discharge was associated with the interval between the CT scan and OR entry (hazard ratio = 0.97 per minute; 95% confidence interval, 0.950–0.998; p = 0.037).

Conclusion

In this study, it was found that interhospital transfer did not influence the surgical outcomes of patients with acute type A aortic dissection. As such, it can be concluded that the transfer of the patients with type A aortic dissection to tertiary hospitals with experienced cardiac surgical teams may not increase the surgical risk.

Acute medical management of aortic dissection

Acute aortic dissection is a life-threatening disease. Current therapeutic guidelines recommend medical therapy with aggressive blood pressure lowering for patients with acute aortic dissection, when they are not indicated for emergency surgery. In particular, patients with aortic dissection without ascending aorta involvement (Stanford type B) are treated medically, unless they have fatal complications. Patients with type B aortic dissection who have critical complications have higher early mortality than that in patients without complications. However, recent advances in thoracic endovascular aortic repair can improve the clinical outcomes in such patients. Accordingly, current guidelines recommend thoracic endovascular aortic repair for patients with complicated type B aortic dissection. However, patients with visceral ischemia still have a poor prognosis, even when they are treated with thoracic endovascular aortic repair; an early diagnosis and intervention is crucial to prevent mortality. Understanding the pathophysiological anatomy that can induce organ malperfusion might be important for an early diagnosis and intervention. This review summarizes the current state of acute medical management in patients with acute aortic dissection, based on current evidence and expert consensus, focusing on patients with type B aortic dissection.

[Complicated acute type B aortic dissection-what does endovascular therapy contribute?]

BACKGROUND

Acute aortic dissection type B is a severe and life-threatening vascular emergency. Complications such as rupture and/or malperfusion of organs are the main reasons for early mortality.

OBJECTIVES

The aim is to provide an overview on important diagnostic radiological findings, conservative as well as endovascular therapeutic options for patients presenting with rupture or malperfusion syndromes.

RESULTS

Medical treatment consisting of blood pressure and heart rate control as well las adequate analgesia remains the cornerstone therapy of all type B aortic dissections. In case of organ malperfusion, various endovascular therapies, e. g., endoluminal fenestration of dissection flap, thoracic stent-graft implantation (TEVAR) or branch vessel stenting, are available. In the case of aortic rupture, TEVAR has become the standard owing to its lower mortality compared to open surgical repair.

DISCUSSION

For the treatment of complicated type B aortic dissection, a number of endovascular options are available. For optimal treatment, profound knowledge of the disease, of the diagnostic workup, and of the interventional procedures is mandatory.

Type B aortic dissection: new perspectives

Background

Stanford type B aortic dissection is one of the aortic catastrophes with a high mortality and morbidity that needs immediate or delayed treatment, either surgically or endovascularly. This comprehensive review article addresses the current status of open, endovascular and hybrid treatment options for type B aortic dissections with the focus on new therapeutic perspectives.

Methods

Evaluation of currently available evidence based on randomized and registry data and personal experience.

Results

All type B dissections require prompt medical treatment to prevent aortic rupture. Acute complicated dissections are nowadays treated by endografting to reroute blood flow into the true lumen and promote false lumen thrombosis and future aortic remodeling. In acute uncomplicated situations the position of endografting is less clear and should be further delineated; however, on the long run also in these situations endografting might be protective for future aortic catastrophes in certain patient categories. In the chronic dissection with aneurysm formation of the descending thoracic and/or thoracoabdominal aorta, especially in connective tissue disorders, open surgery offers nowadays the best immediate results with long durability. Thoracic endografting plays only a minor role in these circumstances but branched and fenestrated endografting are very promising techniques. Hybrid techniques can offer the solution for high risk patients that are not suitable for open surgery.

Conclusions

Emergent thoracic endografting is the golden standard for all complicated type B dissections while uncomplicated patients with high-risk features might benefit from endovascular repair. Open surgery is limited for chronic post dissection aneurysms. Aortic surveillance is of paramount importance in all situations.

Update on the Therapeutic Strategy of Type B Aortic Dissection

Stanford type B aortic dissection (TBAD) is a life-threatening disease. Current therapeutic guidelines recommend medical therapy with aggressive blood pressure lowering for patients with acute TBAD unless they have fatal complications. Although patients with uncomplicated TBAD have relatively low early mortality, aorta-related adverse events during the chronic phase worsen the long-term clinical outcome. Recent advances in thoracic endovascular aortic repair (TEVAR) can improve clinical outcomes in patients with both complicated and uncomplicated TBAD. According to present guidelines, complicated TBAD patients are recommended for TEVAR. However, the indication in uncomplicated TBAD remains controversial. Recent results of randomized trials, which compared the clinical outcome in patients treated with optimal medical therapy and those treated with TEVAR, suggest that preemptive TEVAR should be considered in uncomplicated TBAD with suitable aortic anatomy. However, these trials failed to show improvement in early mortality in patients treated with TEVAR compared with patients treated with optimal medical therapy, which suggest the importance of patient selection for TEVAR. Several clinical and imaging-related risk factors have been shown to be associated with early disease progression. Preemptive TEVAR might be beneficial and should be considered for high-risk patients with uncomplicated TBAD. However, an interdisciplinary consensus has not been established for the definition of patients at high-risk of TBAD, and it should be confirmed by experts including physicians, radiologists, interventionalists, and vascular surgeons. This review summarizes the current understanding of the therapeutic strategy in patients with TBAD based on evidence and expert consensus.

Total Endovascular Treatment of Acute Non-A-non-B Dissection Complicated by Visceral Malperfusion without Primary Entry Tear Coverage

Management of visceral ischemia due to non-A, non-B dissection is extremely challenging due to the position of the primary entry tear at the level of the brachiocephalic vessels. We report on a patient who was admitted for a complicated non-A, non-B-type dissection with visceral and leg ischemia. A covered stent graft was implanted below the primary entry tear to redirect the flow in the true lumen, associated with stents implantation in the visceral arteries, to treat the dissection's static component. The patient did well, without need for bowel resection visceral or late stent restenosis. Stent-graft implantation below the primary entry tear in cases of visceral ischemia due to non-A, non-B dissection seems feasible.

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.