Aortic rupture during aortoplasty in Takayasu arteritis--a rare complication: case report and review of literature

Improving the safety of resuscitative endovascular balloon occlusion of the aorta - Compliant versus semi-compliant balloon systems

OBJECTIVES

Resuscitative endovascular balloon occlusion of the aorta is an alternative to resuscitative thoracotomy in non-compressible torso haemorrhage. Low-profile, compliant balloon catheter systems have been developed, which can be deployed without the need for fluoroscopy. However, concern exists for over inflation and aortic injury, especially as compliant balloon material can stretch reducing syringe feedback and limiting the effectiveness of a safety valve. An alternative material would be a semi-compliant balloon material, but its performance is unknown. The aim of this study was to compare the inflation characteristics of compliant versus semi-compliant balloon systems and to determine whether a pressure relief safety valve can be practically applied to a semi-compliant balloon catheter as a safety device.

METHODS

This was an ex vivo study using porcine segments of thoracic aorta. The study consisted of two phases. The first phase involved intermittent inflation of six compliant balloon and six semi-compliant balloon balloons until balloon or aortic rupture. In the second phase, six semi-compliant balloons with the pressure-relief valve set at 0.45 atmospheres were inflated in the aortas until the valve release, followed by injection with additional 30 mL. Data including pressure, volume, balloon working length, diameter and circumferential stretch ratio were collected.

RESULTS

At failure, mean balloon volume was almost double in compliant balloon group vs semi-compliant balloon group - 49.83 mL (±23.25) and 25.16 mL (±8.93), respectively (p = 0.004), with 36% increase in working length in the compliant balloon group - 81.17 mm (±19.11) vs 59.49 (±4.86) for semi-compliant balloon (p = 0.023). When plotted, the relationship pattern between volume and pressure fit a linear model for the compliant balloon, and a quadratic model for the semi-compliant balloon. Following attempted over inflation with the pressure valve, there was no change in parameters before and after attempted over inflation.

CONCLUSIONS

The inflation profile differs between balloon designs. In contrast to semi-compliant balloons, compliant balloons will accommodate more volume to mitigate increase in pressure. This does not completely eliminate the risk of over inflation. The inflation characteristics of the semi-compliant balloon permit pairing it with a safety valve, which could lead to a development of a safer balloon technology in the future.

Revascularization of Remaining Branch of Aorta in Advanced Takayasu Arteritis Protects Against Wide Range of Perfusion

BACKGROUND

Stroke is a major factor of morbidity in the patients with Takayasu arteritis (TA). Restenosis is more common with endovascular intervention than after bypass surgery, but vascular anastomosis is difficult due to calcification involving the whole thickness of the arterial wall in the burned-out stage of TA. We report a case of advanced TA in which endovascular treatment of the left subclavian artery improved cerebral blood flow (CBF) over a wide range of perfusion in the posterior and anterior circulation.

CASE DESCRIPTION

During medical treatment for TA, a 57-year-old male patient gradually developed ischemic symptoms of both upper limbs and dizziness. Angiography showed occlusion of the brachiocephalic artery and severe stenosis of the left common carotid artery and left subclavian artery. Preoperative single-photon emission computed tomography revealed reductions in the resting CBF and vascular reactivity in the area of the carotid artery and vertebral basilar artery. Chest computed tomography showed calcification of the aortic arch and its branches, and this advanced diffuse calcification indicated probable difficulties in bypass surgery. Therefore we performed percutaneous transluminal angioplasty and stenting for the left subclavian artery. Postoperative single-photon emission computed tomography showed increases in resting CBF in the area of the bilateral internal carotid artery, as well as the vertebrobasilar artery. The patient's various ischemic symptoms improved significantly.

CONCLUSIONS

As collateral circulation is common in advanced TA, the ischemic area is large when the remaining proximal large vessels are occluded. Therefore revascularization of the remaining branch of the aorta in advanced TA may protect against a wide range of perfusion.

Resuscitative endovascular balloon occlusion of the aorta: rupture risk and implications for blind inflation

Background

Resuscitative endovascular balloon occlusion of the aorta (REBOA) is a torso hemorrhage control technique. To expedite deployment, inflation is frequently performed as a blind technique with minimal imaging, which carries a theoretical risk of aortic injury. The objective of this study was to examine the relationship between balloon inflation, deformation and the risk of aortic rupture.

Methods

Compliant balloon catheters were incrementally inflated in segments of cadaveric swine aorta. Serial longitudinal and circumferential measurements were recorded, along with the incidence of aortic rupture.

Results

Fourteen cadaveric swine aorta segments were tested with mean (±SD) baseline aortic diameter (mm) of 14.2±3.4. Rupture occurred in three aortas. The mean baseline diameters (mm) of the aortic segments that were ruptured were significantly smaller than those that did not rupture (8.9±1.2 vs 15.6±1.9; P<0.001). The maximal circumferential stretch ratios were significantly higher in the aorta segments that ruptured compared with those that did not (1.9±0.1 vs 1.5±0.1; P<0.001). The maximal amount of balloon longitudinal deformation was 80 mm (116% longer than the intended working length).

Conclusions

Inflation of aortic balloon catheters carries an inherent risk of aortic injury, which may be minimized through an understanding of the intrinsic characteristics of the aorta and compliant balloons. Smaller diameter aortic segments undergoing overinflation, particularly beyond a circumferential stretch ratio of 1.8, are at risk of aortic rupture.

Level of evidence

Level II.

Challenges of Takayasu Arteritis in Pregnancy: A Case Report

Takayasu arteritis is a rare, chronic vasculitis of unknown etiology characterized by inflammation of the aorta and its main branches. Although Takayasu arteritis mostly affects women of childbearing age, there is a paucity in the literature on pregnancy associated with Takayasu arteritis. Pregnant patients are at increased risk of cardiovascular complications, including hypertension and congestive heart failure, which may jeopardize both maternal and fetal outcomes. Furthermore, optimal management has not yet been established for pregnant patients with Takayasu arteritis, posing a clinical challenge. We present a case of a young woman with Takayasu arteritis whose symptoms and disease activity improved during 2 pregnancies. Although her first pregnancy was complicated with preeclampsia, gestational diabetes, and preterm vaginal delivery, her second pregnancy was uneventful. This case provides a rare glimpse of Takayasu arteritis in pregnancy and highlights the challenges of medical management in gravid patients.

Massive Bleeding from Guidewire Perforation of an External Iliac Artery: Treatment with Hand-made Stent-Graft Placement

We report life-threatening bleeding from an external iliac artery perforation following guidewire manipulation in a patient with atherosclerotic iliac artery disease. This complication was successfully managed by indigenous hand-made stent-graft made from two peripheral stents in the catheterization laboratory.