The Complications of Uncomplicated Acute Type-B Dissection: The Introduction of the Penn Classification

A stable and quantitative method for dimensionality reduction of aortic centerline

Aortic dissection (AD) is a fatal aortic disease with high mortality. Assessing the morphology of the aorta is critical for diagnostic and surgical decisions. Aortic centerline projection methods have been used to evaluate the morphology of the aorta. However, there is a big difference between the current model of primary plane projection (PPP) and the actual shape of individuals, which is not conducive to morphological statistical analysis. Finding a method to compress the three-dimensional information of the aorta into two dimensions is helpful to clinical decision-making. In this paper, the evaluation parameters, including contour length (CL), enclosure area, and the sum of absolute residuals (SAR), were introduced to objectively evaluate the optimal projection plane rather than artificial subjective judgment. Our results showed that the optimal projection plane could be objectively characterized by the three evaluation parameters. As the morphological criterion, SAR is optimal among the three parameters. Compared to the optimal projection plane selected by traditional PPP, our method has better AD discrimination in the analysis of aortic tortuosity, and is conducive to the clinical operation of AD. Thus, it has application prospects for the preprocessing techniques for the geometric morphology analysis of AD.

Outcomes and risk management in type B aortic dissection patients with acute kidney injury: a concise review

Purpose

Type B aortic dissection is a rare but life-threatening disease. Thoracic endovascular aortic repair (TEVAR) was widely used for Type B aortic dissection patients in the last decade due to the lower mortality and morbidity compared with open chest surgical repair (OCSR). AKI in type B aortic dissection is a well-recognized complication and indicates poor short-term and long-term outcome. The objective of this concise review was to identify the risk factors and the impact of AKI on type B aortic dissection patients.

Methods and results

A literature search was performed using PubMed, Embase, MEDLINE, and Cochrane Library with the search terms ‘type B aortic dissection’ and ‘acute kidney injury’ (AKI), and all English-language literatures published in print or available online from inception through August 2020 were thoroughly reviewed. Studies that reported relative AKI risks and outcomes in type B aortic dissection patient were included. Major mechanisms of AKI in type B aortic dissection included renal hypoperfusion, inflammation response, and the use of contrast medium. Type B aortic dissection patients with AKI significantly had increased hospital stay duration, need of renal replacement therapy, and 30-d and 1-year mortality.

Conclusions

AKI in type B aortic dissection is a well-recognized complication and associated with poor short-term and long-term outcome. Early identification of high-risk patients, early diagnosis of AKI, stabilization of the hemodynamic parameters, avoidance of nephrotoxic drugs, and optimization of the use of contrast agents are the major strategies for the reduction of AKI in type B aortic dissection patients.

The Penn Classification Predicts Hospital Mortality in Acute Stanford Type A and Type B Aortic Dissections

OBJECTIVES

Mortality in acute aortic dissection varies depending on anatomic location, extent, and associated complications. The Stanford classification guides surgical versus medical management. The Penn classification stratifies mortality risk in patients with Stanford type A aortic dissections undergoing surgery. The objective of the present study was to determine whether the Penn classification can predict hospital mortality in patients with acute Stanford type A and type B aortic dissections undergoing surgical or medical management.

DESIGN

Retrospective, observational study.

SETTING

Tertiary care, university hospital.

PARTICIPANTS

Patients with acute aortic dissection between January 2008 and December 2017.

INTERVENTIONS

Examination of hospital mortality after surgical or medical management.

MEASUREMENTS AND MAIN RESULTS

Three hundred fifty-two patients had confirmed dissections (186 type A, 166 type B). The overall mortality was 18.8% for type A and 13.3% for type B. Penn class A patients with type A or type B dissections undergoing surgical repair had the lowest mortality (both 3.1%). Penn class B, C, or B+C patients with type A dissections and Penn class B+C patients with type B dissections undergoing medical management had the greatest incidence of mortality (50.0%-57.1%). All others had intermediate mortality (6.7%-39.3%). Logistic regression analysis demonstrated that Penn class B, C, and B+C patients had a greater odds of mortality and predicted mortality than did Penn class A patients.

CONCLUSIONS

The Penn classification predicts hospital mortality in patients with acute Stanford type A or type B aortic dissections undergoing surgical or medical management. Early endovascular repair may confer lower risk of mortality in patients with type B dissections presenting without ischemia.

Fate of uncomplicated acute type B aortic dissection and impact of concurrent aortic dilatation on remote aortic events

OBJECTIVE

This study aimed to describe the reliable prognostic factors of mortality and subsequent aortic events during the follow-up of uncomplicated type B acute aortic dissection.

METHODS

From January 2004 to December 2014, 255 patients with uncomplicated type B acute aortic dissection were admitted to our hospital. Cox proportional hazards analysis was performed to identify risk factors for all-cause mortality, aorta-related mortality, and aortic events.

RESULTS

In-hospital mortality was observed in 7 patients (2.7%). The rates of 5-year freedom from all-cause mortality, aorta-related mortality, and aortic events were 79.4% ± 2.9%, 93.3% ± 2.0%, and 71.7% ± 3.4%, respectively. The rate of 5-year freedom from aortic events was significantly lower among those with a patent false lumen (P = .006). Age and descending aorta diameter were independent risk factors of all-cause and aorta-related mortality (hazard ratio [HR], 1.08 and 1.13; 95% confidence interval [CI], 1.04-1.10 and 1.03-1.24; P = .0001 and .007, respectively). Independent risk factors for aortic events were descending aorta diameter, false lumen thickness, and dilatation of abdominal aorta (HR, 1.06; 95% CI, 1.02-1.12; P = .006; HR, 1.07; 95% CI, 1.04-1.11; P = .00002; HR, 2.01; CI, 1.20-3.38; P = .008).

CONCLUSIONS

In uncomplicated type B acute aortic dissection, the age and dilatation of the thoracic aorta were associated with a higher risk of death, whereas false lumen thickness and concurrent abdominal aortic dilatation augment the risk for aortic events.

How should we manage type B aortic dissections?

Dissection of the descending aorta is a serious and potentially lethal event. Treatment options consist of medical therapy, open surgical replacement of the affected aorta and thoracic endovascular repair. In acute cases, medical treatment is started initially. When complicated, endovascular repair is generally considered as first choice treatment, except for connective tissue disorders where open surgery remains the standard. In stable, uncomplicated patients with risk factors for future aortic growth pre-emptive endovascular repair should be considered in the sub-acute phase of the dissection. The treatment strategy in chronic dissections is somewhat debated. Long-term results and aortic remodeling of endovascular repair are disappointing and open surgery remains the standard.

A novel anatomic severity grading score for acute Type B aortic dissections and correlation to aortic reinterventions after thoracic endovascular aortic repair

Background

We introduce a novel preoperative anatomic severity grading system for acute type B aortic dissections and validate the system in a cohort of patients who underwent thoracic endovascular aortic repair.

Methods

We identified a cohort of patients who received thoracic endovascular aortic repair (TEVAR) for acute type B aortic dissection from 2008 to 2014. We developed an anatomic severity grading score (ASG) to measure attributes of aortic anatomy that we hypothesized may affect difficulty or durability of repair. Measurements were made using computed tomography angiography images and based on hypothesized severity, giving a potential score range of 0-38.

Results

We analyzed the computed tomography angiography images on a cohort of 30 patients with acute type B aortic dissection who underwent TEVAR. We created an area under the receiver operating characteristic curve (AUROC) using anatomic severity grading to predict aortic-related reinterventions. The AUROC was 0.72 (95% CI 0.39 to 1.1). Guided by the AUROC, we divided patients into two groups: a low-score group with anatomic severity grading scores <23 (n = 22), and a high-score group with scores ≥23 (n = 8). With this cutoff, anatomic severity grading exhibited 80% sensitivity and 84% specificity in predicting aortic-related reinterventions, with reinterventions in 50% of high-score patients and 4.5% of low-score patients (P = 0.011). The high score group also had significantly greater blood loss (200 vs 100 mL, P = 0.038), fluoroscopy time (36.0 vs 16.6 min; P = 0.022), and a trend for increased procedure time (164 vs 95 min; P = 0.083) than the low-risk group. Kaplan-Meier analysis revealed that the high-score group had a significantly decreased freedom from aortic-related reinterventions than the low-score group (38% vs 100% at 12-month followup; log rank P = 0.001).

Conclusions

A preoperative anatomic severity grading score for acute type B aortic dissections consists of analysis of the proximal landing zone, curvature and tortuosity of the aorta, dissection anatomy, aortic branch vessel anatomy, and supraceliac aorta anatomy. Anatomic severity grading scores ≤23 are an excellent predictor of aortic-related reinterventions.

[Pre- and postoperative imaging of type B aortic dissection]

Type B aortic dissections are serious diseases with a 60 to 80 % 5-year survival rate. Although typically managed with a medical treatment, surgery may be necessary in the acute/subacute or the chronic phase if significant complications are encountered. For these patients, CT angiography is the first-line imaging modality, used for indicating and preparing the surgical procedure as well as for follow-up. Physicians in charge of these patients should be familiar with the key reading points. Visceral malperfusion is the most common acute complication, while aneurysmal dilatation of the false lumen is the most common chronic complication, with surgical management generally indicated when the axial diameter of the aorta exceeds 55mm. Endovascular treatment tends to replace open surgery: it requires precise measurements and identification of the entry tear (contribution of 4D-MRA).

Management of acute aortic dissection

A new appraisal of the management of acute aortic dissection is timely because of recent developments in diagnostic strategies (including biomarkers and imaging), endograft design, and surgical treatment, which have led to a better understanding of the epidemiology, risk factors, and molecular nature of aortic dissection. Although open surgery is the main treatment for proximal aortic repair, use of endovascular management is now established for complicated distal dissection and distal arch repair, and has recently been discussed as a pre-emptive measure to avoid late complications by inducing aortic remodelling.

Perioperative transesophageal echocardiography for aortic dissection

PURPOSE

Aortic dissection is an infrequent but serious condition that often requires immediate operative intervention. We explore recent developments in the classification of aortic dissection and perioperative transesophageal echocardiography that assist with quantifying the severity of disease and facilitate its management.

PRINCIPAL FINDINGS

We describe the pivotal role of echocardiography in relation to key surgical considerations such as cannulation, aortic root surgery, perfusion in the aortic arch vessels, stenting in hybrid arch repair, and timing of preventative surgery.

CONCLUSION

Developments in the classification of aortic dissection have improved our perspective and understanding of the key presenting features that affect mortality. Improvements in patient outcome may be achieved in part by appropriately timed echocardiography-guided surgery.