Right Ventricular Outflow Tract Injury During Deep Dissection in Valve-Sparing Aortic Root Replacement

For valve-sparing aortic root replacement (VSARR), including reimplantation and remodeling, deep surgical dissection around the aorta allows the graft to encase the basal ring, preventing basal dilation, cusp prolapse, and subsequent aortic insufficiency. However, deep periaortic dissection is often avoided due to the risk of injury to surrounding structures, such as the right ventricular outflow tract (RVOT). Techniques for repairing the RVOT are not well described in the literature. This case outlines a successful repair of the RVOT after injury during deep dissection for a David procedure.  

The patient was a 45-year-old male with no past medical history who presented to the emergency department with right eye pain, blurriness, and vision changes. A computed tomography (CT) scan of the head demonstrated right common carotid artery dissection and occlusion, while CT angiography revealed a type A aortic dissection involving the ascending aorta, arch, innominate artery, and the origin of the great vessels, along with a 5.5 cm ascending thoracic aortic fusiform aneurysm. The patient was transferred to the authors’ center where he underwent an aortic dissection repair. 

During the procedure, valve-sparing aortic root replacement was performed using the David procedure, followed by ascending aorta and transverse zone 2 arch replacement with a 26 mm multibranch graft.  Total replacement of the right common carotid artery at the neck was achieved with an 8 mm graft, alongside aorto-left common carotid artery and aorto-right subclavian artery bypass using 8 mm and 10 mm grafts. Right subclavian artery cannulation and repair were also completed with an 8 mm graft.  

Intraoperatively, the root was noted to measure approximately 5.5-6 cms, and a transverse tear was identified in the ascending aorta. The right common carotid artery was dissected out first through a separate neck incision. The right subclavian artery was used for cannulation due to dissection of the innominate artery and right common carotid artery. The proximal right subclavian artery was clamped, and an arteriotomy was made to sew an 8 mm graft to the right subclavian artery in a running fashion using 5-0 Prolene for arterial perfusion. The patient was cooled down to 28 degrees Celsius for hypothermic circulatory arrest.   

The primary intimal tear was located at the proximal ascending aorta, and the dissection flap ended 5 cms from the left subclavian artery. The aorta was cross-clamped, and cardioplegia was administered retrograde throughout the case. The ascending aorta was transected approximately 1 cm above the sinotubular junction (STJ). The root was aneurysmal, measuring approximately 5.5-6 cms. The aortic leaflets were normal, except for mild thickening of the free margin of the center and some fenestration, which deemed them appropriate for valve-sparing replacement.  

The surgical dissection around the aortic root started at the left noncommissural side above the left atrium and extended toward the right atrium, delving circumferentially down to the subannular area at the basal ring level. The most difficult portion of the dissection involved the right ventricular outflow tract (RVOT), which was attached to the right coronary sinus approximately 1 cm above the basal ring and thinned close to the right noncommissure. The RVOT was rolled from the left ventricular outflow tract (LVOT) during deep dissection and was inadvertently injured with scissors above the nadir of the right coronary sinus.  

To address this, the RVOT incision was extended from the nadir of the right coronary sinus toward the left-right and right noncommissures, extending approximately 2 cms long to expose the muscular septum, allowing for the placement of  subannular stitches. Care was taken to avoid injuring the tricuspid or pulmonic valves.  

Non-pledgeted 2-0 Ethibond subannular sutures were placed at the basal ring on the right coronary sinus side, with the stitch placed through the LVOT, the interventricular muscular septum, and into the right ventricle below the level of the nadir of the right coronary sinus. This allowed the graft to be well secured below the basal ring level, effectively securing the basal ring. Notably, care was taken to avoid damage to the conducting system and the chordae of the tricuspid valve.   

A 34 mm graft was plicated to 30 mms over the sizer, and the left-right commissural side was notched. All 12 of the sutures were passed through the plicated end of the graft. The graft was then loosely tied to the basal ring subannular area to avoid inducing aortic stenosis. On the right coronary side, the graft was tied down to the muscular septum without trapping any chordae of the tricuspid valve.  

To repair the RVOT injury, one arm of a 4-0 Prolene was sewn through the muscular septum and exited through the graft at the left-right commissure side. The other arm of the 4-0 Prolene was sutured through the free wall of the RVOT and tied. Then the opening of RVOT was closed in a running suture fashion by sewing the free wall of RVOT, the muscular septum, and the Dacron graft in two rows. This allowed the RVOT free wall to cover the graft and ensured that the graft was positioned at the right ventricular side over the ventricular septum. Care was taken to avoid the tricuspid valve chordae. The repair was tested by inflating the right ventricle, and no bleeding was noted from the RVOT.  

After the RVOT repair was completed, the aortic arch was transected between the left common carotid artery and the left subclavian artery under circulatory arrest. The dissection ended approximately 4-5 cms beyond the left subclavian artery. A 26 mm multibranch graft was sewn to the zone 2 arch with 5-0 Prolene in a running fashion, with the graft placed inside the aorta to protect the intima and dissection flap.  

The left common carotid artery was then reimplanted with 5-0 Prolene in a running fashion to secure the side branch. Next, the right common carotid artery was clamped distally and transected through the nondissected portion, revealing that the majority of the right common carotid artery was completely thrombosed.  

Another 8 mm side branch of the multibranch graft was then pulled through from the chest to the neck and sewn to the distal common carotid artery with 5-0 Prolene in a running fashion. The right common carotid artery was then suture ligated with 4-0 Prolene distally and with 0-0 silk proximally. 

Attention was moved back to the aortic root, where the coronary buttons were anastomosed to the graft using 5-0 Prolene in a running fashion without difficulty.  The distal 28 mm graft was anastomosed to the proximal 34 mm graft to plicate the STJ and create a new STJ with 4-0 Prolene in running suture fashion. The aorta was unclamped, and the most proximal branch graft of the arch multibranch graft was sewn to the 8 mm graft, which was sewn to the right subclavian artery for cardiopulmonary bypass. 

After reconstruction and repair, transthoracic echocardiography showed that the aortic valve was competent without any insufficiency. The patient did well postoperatively and was discharged on postoperative day (POD) 11.  The postoperative course was remarkable for an immobile right vocal cord that required vocal cord injection. He was on continuous renal replacement therapy (CRRT) for one day, and renal function recovered before discharge. However, he was readmitted on PODs 14 to 18 for cardiac tamponade, which required pericardiocentesis (1150mL) and drain placement.  

At the three-month clinic follow-up, the patient was recovering well and was active with cardiac rehabilitation and physical therapy. The vocal cord function had recovered. Recent three-month CT and transthoracic echocardiogram showed normal functioning of the aortic valve without any aortic insufficiency or pseudoaneurysm. 

In conclusion, it is not uncommon to inadvertently incise the RVOT during root dissection. No complications arose from opening the RVOT, and a simple and fast technique to repair RVOT injuries was demonstrated. A total of five RVOT repairs were performed, and all patients did well. It was concluded that deep periaortic dissection is important for valve-sparing aortic root replacement (VSARR) and that the benefits generally outweigh the risks of RVOT injury.   

Disclosure 

Dr. Yang is supported by the National Heart, Lung, and Blood Institute of the National Institutes of Health (NHLBI/NIH) under award numbers R01HL141891 and R01HL151776. Dr. Ramdeen is supported by the NHLBI/NIH under award number T32HL166113. This content is solely the responsibility of the authors and does not necessarily represent the views of the NHLBI/NIH. 

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