Malperfusions in Acute Type B Aortic Dissection—Predictors of Outcomes

Intravascular Ultrasound Enhances the PETTICOAT Technique in Endovascular Therapy for Complicated Type B Aortic Dissection with Malperfusion Syndrome

BACKGROUND

To present the value of intravascular ultrasound (IVUS) in diagnosis and treatment of complicated type B aortic dissection with malperfusion. Especially, the value of IVUS regarding the treatment strategy, reoperation rate, acute kidney injury, and false lumen thrombosis was investigated.

METHODS

Retrospective analysis of 25 type B aortic dissection cases with malperfusion treated with endovascular therapy from April 2019 to August 2022. In 17 cases, angiography and IVUS were applied during the operation (IVUS group), and in 8 cases, angiography was used without IVUS (control group) for final intraoperative control. IVUS was used to assess the true lumen collapse and to decide if additional bare stenting was necessary or not. Details from patients' charts and documentation from surgeries were analyzed. The endovascular technique included thoracic endovascular aortic repair with primary entry sealing and-if needed-bare stenting of the true lumen distal of the entry tears using the Provisional Extension To Induce Complete Attachment (PETTICOAT) technique.

RESULTS

All patients presented with pain localized mostly (48%) in thorax and abdomen. In all patients, the proximal entry tear of the dissection was covered using thoracic endovascular aortic repair. The PETTICOAT technique was applied in 13 cases (52%), whereas most combined procedures were applied in the IVUS group (12 compared to 1; P = 0.02). A total of 3 patients (1 in the control group, 12.5% and 2 in the IVUS group, 11.8%) underwent a bowel resection. Totally 8 patients (32%) underwent a reoperation in aorta (3 during the hospital stay). There were no statistical differences between IVUS and control group regarding the preoperative findings, the reoperation rates, and the postoperative complications. Five patients died (4 during the hospital stay); 1 in control and 4 in IVUS group; P = 0.53. The follow-up included a clinical and a computed tomography angiography examination. No statistically significant difference regarding occurrence and extension of false lumen thrombosis was observed between the 2 groups.

CONCLUSIONS

The IVUS and control groups showed no difference in survival rates. The use of IVUS extended the indication for PETTICOAT technique with statistically significant difference. A milder form of acute kidney injury presented in the IVUS group compared to the control group. In addition, a stronger correlation between IVUS and the avoidance of an aorta reoperation was observed, although it did not reach statistical significance.

Visceral and renal malperfusion syndromes in acute aortic dissection type A: the fate of the branch vessel

BACKGROUND

Malperfusion in acute aortic dissection is not uncommonly observed and associated with a highly significant increase in mortality and morbidity. Of the various malperfusion syndromes, visceral and renal involvement is the most challenging in terms of correct and timely diagnosis as well as the choice of management strategy. The aim of this study was to identify the pathology and associated fate of each visceral and renal vessel in acute type A dissections.

METHODS

Over a 12-year period, 167 consecutive patients with acute dissection type A extending into the thoracoabdominal aorta were included and radiographic images analyzed with a focus on individual branch vessel pathology and dependent organ perfusion.

RESULTS

Sixty-five patients (39%) were diagnosed with radiological signs of malperfusion on the CT Images. Of those, 20% expired during the hospital stay, compared to 8% without malperfusion. The left renal artery was the most frequently affected by dissection (31%) or false lumen supply (28%). False lumen perfusion was more often associated with manifest malperfusion than an extension of the dissection flap into the branch vessel. During the study period, there was no preference of surgical procedure treating the malperfusion.

CONCLUSIONS

Malperfusion of the visceral/renal branches of a dissected aorta represents a manifest indicator for postoperative mortality and morbidity. Neither clinical outcome, nor the fate of individual vessels can reliably be predicted prior to proximal reconstruction and thus, surgical strategy cannot generally be defined alone by radiological findings.

Re-expansion of Thrombosed False Lumen after Aortic Dissection Due to Collateral Retrograde Flow from the Aortic Branches

Re-expansion of thrombosed false lumen after aortic dissection due to collateral retrograde flow from the aortic branches has rarely been reported. Surgical or endovascular local management such as ligation or occlusion of culprit arteries may not be effective in case retrograde blood flow to the false lumen might occur again from another branch after the operation. Here, we report a 68-year-old woman with re-expansion of the thrombosed false lumen after acute type B aortic dissection due to collateral retrograde flow from the aortic branches successfully treated with tranexamic acid therapy and antihypertensive therapy.

Endovascular repair of acute complicated type B aortic dissection-systematic review and meta-analysis of long-term survival and reintervention

Background

Thoracic endovascular repair (TEVAR) is considered the first-line therapy in the repair of acute complicated type B aortic dissection (AC-BAD). Given the difficulty of designing randomized trials in this surgical cohort, long-term outcome data is limited. This systematic review and meta-analysis provide a complete aggregation of reported long-term survival and freedom from reintervention of AC-BAD patients based on the existing literature.

Methods

Three databases were searched from date of database inception to January 2021. The relevant references were identified and baseline cohort characteristics, survival and freedom from reintervention were extracted. The primary endpoints were survival and freedom from reintervention, whilst secondary endpoints were post-operative outcomes such as cord ischemia and endoleak. Kaplan-Meier curves were digitized and aggregated as per established procedure.

Results

A total of 2,812 references were identified in the literature search for review, with 46 selected for inclusion. A total of 2,565 patients were identified, of which 1,920 (75%) were male. The mean age of the cohort was 59.8±5.8. Actuarial survival at 2, 4, 6 and 10 years was 87.5%, 83.2%, 78.5% and 69.7%, respectively. Freedom from all secondary reintervention at 2, 4, 6, 8 and 10 years was 74.7%, 69.1%, 65.7%, 63.9% and 60.9%, respectively. When accounting for study quality, actuarial survival at 2, 4, 6 and 8 years was 85.4%, 79.1%, 69.8% and 63.1%, respectively. Freedom from all secondary reintervention at 2, 4, 6 and 8 years was 73.2%, 67.6%, 63.7% (maintained), respectively.

Conclusions

TEVAR is associated with promising long-term survival extended to 10 years, though rates of freedom from reintervention remain an ongoing point for improvement. Randomized controlled trials comparing endovascular with open repair in the setting of acute, complicated type B aortic dissection are needed.

Management of Acute, Complicated Type B Aortic Dissection

Management of acute complicated Type B aortic dissection (TBAD) requires a multidisciplinary approach with careful evaluation and understanding of the complicating features. Patients who present with or progress to a complicated TBAD must be triaged and managed rapidly due to the high morbidity and mortality even in the presence of optimal medical, endovascular, and open therapies. When required, invasive therapies can be broken down most simply into four treatments: thoracic endograft placement, aortic fenestration, branch vessel stenting, and open repair. However, which therapy to offer and in which order is often unclear. In this review, focus is placed on clinical presentation, diagnosis, and explanation for one or a combination of these therapies. In addition, contraindications as well as expected outcomes, complications, and adjunct therapies will be reviewed. The advent of advanced endovascular techniques has certainly improved the immediate morbidity and mortality of acute complicated TBAD; however, much remains to learn about patient selection and therapeutic intervention performed.

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.

Unique characteristics of the type B aortic dissection patients with malperfusion in the Vascular Quality Initiative

OBJECTIVE

Type B aortic dissection (TBAD) complicated by malperfusion carries high morbidity and mortality. The present study was undertaken to compare the characteristics of malperfusion and uncomplicated cohorts and to evaluate the long-term differences in survival using a granular, national registry.

METHODS

Patients with TBAD entered into the thoracic endovascular aortic repair/complex endovascular aortic repair module of the Vascular Quality Initiative from 2010 to 2019 were included. The demographic, radiographic, operative, postoperative, in-hospital, and long-term reintervention data were compared between the malperfusion and uncomplicated TBAD groups using t tests and χ² analysis, as appropriate. Overall survival was compared using Cox regression to generate survival curves.

RESULTS

Of the 2820 included patients, 2267 had uncomplicated TBAD and 553 had malperfusion. The patients with malperfusion were younger (age, 55.8 vs 61.2 years; P < .001), were more often male (79.7% vs 68.1%; P < .001), had a higher preoperative creatinine (1.8 vs 1.1 mg/dL; P < .001), had more often presented with an American Society of Anesthesiologists class of 4 or 5 (81.9% vs 58.4%; P < .001), and had more often presented with urgent status (77.4% vs 32.8%; P < .001). In contrast, the uncomplicated TBAD group had had more medical comorbidities, including coronary artery disease and chronic obstructive pulmonary disease, and a larger aortic diameter (4.0 cm vs 4.9 cm; P < .001). The malperfusion group more frequently had proximal zones of disease in zones 0 to 2 (38.6% vs 31.5%; P = .002) and distal zones of disease in zones 9 and above (78.7% vs 46.2%; P < .001), with a greater number of aortic zones traversed (7.7 vs 5.1; P < .001) and a greater frequency of dissection extension into branch vessels (61.8% vs 23.1%; P < .001). Patients with malperfusion also exhibited greater case complexity, with a greater need for branch vessel stenting and longer procedure times. The overall incidence of postoperative complications was greater in the malperfusion group (39.4% vs 17.1%; P < .001) and included a greater rate of spinal cord ischemia (6.3% vs 2.2%; P < .001), acute kidney injury (10.4% vs 0.9%; P < .001), and in-hospital mortality (11.6% vs 5.6%; P < .001). In-hospital reintervention was also greater for the malperfusion patients (14.5% vs 7.4%; P < .001), although the incidence of long-term reinterventions was similar between the two groups (8.7% vs 9.7%; P = .548). A proximal zone of disease in zone 0 to 2 was associated with decreased survival. In contrast, a distal zone of disease in 9 and above, in-hospital reintervention, and long-term follow-up were associated with increased survival. Despite these differences, long-term survival did not differ between the malperfusion and uncomplicated groups (P = .320.) CONCLUSIONS: Patients presenting with TBAD and malperfusion represent a unique cohort. Despite the greater need for branch vessel stenting and in-hospital reintervention, they had similar long-term reintervention rates and survival compared with those with uncomplicated TBAD. These data lend insight with regard to the observed differences between uncomplicated and malperfusion TBAD.