Total body retrograde perfusion during operations on the descending thoracic aorta

Retrograde Inferior Vena caval Perfusion for Total Aortic arch Replacement Surgery (RIVP-TARS): study protocol for a multicenter, randomized controlled trial

Background

During total aortic arch replacement surgery (TARS) for patients with acute type A aortic dissection, the organs in the lower body, such as the viscera and spinal cord, are at risk of ischemia even when antegrade cerebral perfusion (ACP) is performed. Combining ACP with retrograde inferior vena caval perfusion (RIVP) during TARS may improve outcomes by providing the lower body with oxygenated blood.

Methods

This study is designed as a multicenter, computer-generated, randomized controlled, assessor-blind, parallel-group study with a superiority framework in patients scheduled for TARS. A total of 636 patients will be randomized on a 1:1 basis to a moderate hypothermia circulatory arrest (MHCA) group, which will receive selective ACP with moderate hypothermia during TARS; or to an RIVP group, which will receive the combination of RIVP and selective ACP under moderate hypothermia during TARS. The primary outcome will be a composite of early mortality and major complications, including paraplegia, postoperative renal failure, severe liver dysfunction, and gastrointestinal complications. All patients will be analyzed according to the intention-to-treat protocol.

Discussion

This study aims to assess whether RIVP combined with ACP leads to superior outcomes than ACP alone for patients undergoing TARS under moderate hypothermia. This study seeks to provide high-quality evidence for RIVP to be used in patients with acute type A aortic dissection undergoing TARS.

Trial registration

Clinicaltrials.gov, ID: NCT03607786. Registered on 30 July 2018.

Electronic supplementary material

The online version of this article (10.1186/s13063-019-3319-2) contains supplementary material, which is available to authorized users.

Combining Cerebral Perfusion With Retrograde Inferior Vena Caval Perfusion for Aortic Arch Surgery

Hypothermic circulatory arrest and selective cerebral perfusion are standard procedures during total arch replacement to treat acute type A aortic dissection. However, organ ischemia during anastomosis between the graft and descending aorta contribute to high risk of mortality and morbidity. Here we describe the combination of antegrade cerebral perfusion and retrograde inferior vena caval perfusion as a way to ensure continual perfusion of the brain, abdominal viscera, and spinal cord during anastomosis and thereby improve outcomes of total arch replacement.

Spinal cord retrograde perfusion: review of the literature and experimental observations

BACKGROUND

Spinal cord damage represents a devastating complication of thoracic and thoracoabdominal aortic surgery. Retrograde perfusion as an alternative route to protect the spinal cord has recently been investigated with controversial results. We reviewed the literature and analyzed additional experimental observations.

METHODS

Ten juvenile pigs were divided into control and study groups (A and B, respectively). Through a lateral thoracotomy the distal aortic arch was cannulated and connected to a cardiotomy reservoir. All animals underwent 40-minute single cross-clamping of the proximal descending aorta while keeping proximal systolic arterial pressure above 100 mmHg. In group B, normothermic arterial blood was delivered retrogradely through the azygos vein, maintaining perfusion pressure within 25-30 mmHg. Animals were allowed to recover to perform a primary neurologic evaluation.

RESULTS

Flaccid paraplegia was uniformly observed in group A. In group B, all animals showed mild-to-moderate voluntary hind limb movements on awakening (p = 0.007). Controls also showed urine incontinence short after cross-clamping, and this was not observed in group B (p = 0.008). A different veno-arterial oxygen step-down was observed in blood collected from the excluded aorta in the two groups (p < 0.001).

CONCLUSIONS

Preliminary results indicate that controlled retrograde normothermic perfusion alone through the azygos system provides some degree of protection from spinal cord ischemia. Bladder dysfunction may represent a simple test to detect massive cord damage intraoperatively. Retrograde spinal cord perfusion warrants further investigation.

Cannulation of the Extrathoracic Left Common Carotid Artery for Thoracic Aorta Operations Through Left Posterolateral Thoracotomy

The femoral artery is the usual site of arterial cannulation in thoracic aorta operations through left posterolateral thoracotomy that require cardiopulmonary bypass (CPB) with deep hypothermic circulatory arrest (DHCA). The advantage of this perfusion route is in limiting the duration of circulatory arrest. It is associated, however, with the risk of retrograde embolization or, in cases involving aortic dissection, malperfusion of vital organs. To prevent these risks, we have used the extrathoracic left common carotid artery as the perfusion route. From December 1999 to January 2003, we used cannulation of the left extrathoracic common carotid artery in 42 thoracic aorta operations through posterolateral thoracotomy with an open proximal anastomosis technique during DHCA. The indication for thoracic aortic repair was atherosclerotic ulcer in 7 cases, chronic aortic aneurysm in 18, acute type B dissection in 5, and chronic type B dissection in 12. Cannulation of the extrathoracic left common carotid artery was successful in all patients. Postoperative recovery was uneventful, with no cerebrovascular events in all cases. No cannulation-related complications were observed. One patient died from cardiac insufficiency on postoperative day 5. No peripheral neurological deficits (paraplegia or paraparesis) were observed. Postoperative complications included atrial fibrillation in five patients, reoperation to control hemorrhage in six, respiratory insufficiency in nine, and renal insufficiency in six. These results indicate that cannulation of the left extrathoracic common carotid artery is a useful, reliable method for proximal perfusion during CPB in patients undergoing repair of the descending thoracic aorta through left posterolateral thoracotomy. By providing effective perfusion of the brain, this technique can prolong safe DHCA time. Another advantage is the prevention of cerebral emboli, ensuring retrograde flow to the aortic arch.

Successful salvage of inferior vena cava rupture during reoperative repair for ascending aortic aneurysm

A 44-year-old man underwent reoperative repair for ascending aortic aneurysm at our hospital. He had received aortic valve replacement due to severe aortic regurgitation 4 years previously. The cardiopulmonary bypass was set up through the femoral arterial and venous cannula. An unusual experience of rupture of the abdominal inferior vena cava was encountered after total-body retrograde perfusion. The tragic situation was successfully salvaged by recannulation into the intrapericardial inferior vena cava and repair of the several perforations on abdominal inferior vena cava. The patient recovered smoothly except for mild pancreatitis. The causes of rupture of the inferior vena cava are discussed here.

Extrathoracic cannulation of the left common carotid artery in thoracic aorta operations through a left thoracotomy: preliminary experience in 26 patients

BACKGROUND

In aortic operations performed through a left thoracotomy, which require total bypass and deep hypothermic circulatory arrest, femoral artery cannulation is commonly used for arterial perfusion. This route limits the time of safe circulatory arrest and is associated with the risks of retrograde embolization or, in the case of aortic dissection, malperfusion of the vital organs. To overcome these problems, we have used cannulation of the extrathoracic left common carotid artery to ensure a central a route of arterial perfusion in these operations. The preliminary results are presented.

METHODS

Between December 1999 and April 2001, we used left common carotid artery cannulation in 26 operations on the thoracic aorta performed through a posterolateral thoracotomy with an open technique during deep hypothermic circulatory arrest. Institutional review board approval and informed consent were obtained. The indications included perforating atherosclerotic ulcer (n = 5), chronic aortic aneurysm (n = 9), acute type B aortic dissection (n = 3), and chronic dissection of the thoracic aorta (n = 9). Transcranial Doppler ultrasonographic monitoring of both the right and left middle cerebral arteries was used to assess the adequacy of cerebral bihemispheric perfusion and to determine the differences in blood flow velocities throughout the procedure.

RESULTS

Left common carotid artery cannulation was successful in all patients. All patients awoke from the operation, and none had cerebrovascular accidents. None died in the hospital, and complications related to carotid artery cannulation were not observed. None of the patients experienced postoperative paraplegia. In all patients transcranial Doppler monitoring indicated the absence of cerebral embolic phenomena throughout the entire procedure. Significant differences in middle cerebral artery flow velocities were observed at different phases of the procedures and between the right and left middle cerebral arteries during carotid cannulation and during selective cerebral perfusion. Nevertheless, the maximal drop of right middle cerebral artery blood velocity during selective perfusion through the left common carotid artery was within 50% of the left middle cerebral artery velocity, indicating adequate bihemispheric perfusion.

CONCLUSIONS

In patients undergoing aortic operations through a left thoracotomy, extrathoracic left common carotid artery cannulation was a safe and effective means of providing proximal arterial inflow during cardiopulmonary bypass, which can be used to selectively perfuse the brain, as well as to prevent embolic phenomena in the arch vessels.