Bental Procedure | CardiacSurgeryAssist

Advanced Procedures - Bentall Procedure

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Objectives - Topics to be Covered

Anatomy - refer to aortic valve and aortic replacements pages
Diseases associated with a combination of:
- Aortic Root Dilation
- Aortic Valve Insufficiency
- Aortic Aneurysm
Procedure
- Cannulation strategy
- When to use deep hypothermic circulatory arrest (DHCA)
- Preparing the aortic root
- Removal of the Aorta and aortic valve
- Creating and preparing the coronary buttons
- Sizing and placing the aortic valve/graft composite
Distal anastomosis
Modifications
- reenforcing the root

Manifestations of aortic valve disease in the context of connective tissue disorders include valvular stenosis, regurgitation, and/or thoracic aortic aneurysms (Tables 1 and 2). Both inherited and inflammatory connective tissue disorders contribute to aortic valve damage with increased susceptibility associated with specific gene variants. There is insufficient knowledge regarding the underlying mediators, and thus appropriate immunotherapy to target specific cytokines in order to dampen the inflammatory response. For example, in Marfan’s syndrome, TGF-β has been documented to play a crucial role and thus presents a therapeutic target. Ultimately, the goal of such therapies would be the induction of remission without the need for valve replacement, which is associated with inherent risk. Despite demonstrating promising results in the treatment of Ehlers–Danlos syndrome (EDS), surgical intervention of the aortic valve has been associated with many complications, including the need for recurring operations in Behcet disease and ankylosing spondylitis and a high mortality and morbidity rate in systemic lupus erythematosus (SLE).

Exerts from Disorders of the Aorta and Aortic Valve in Connective Tissue Diseases Bogna Grygiel-Górniak1 Published online: 19 June 2020 #The Author(s) 2020 &Mary-Tiffany Oduah1 & Abdulbaril Olagunju1 & Michal Klokner1; Current Cardiology Reports (2020) 22: 70

Table 1: Connective tissue diseases and their manifestations in the aorta and aortic valve

Aortic disorders and aortic valve manifestations

Aortic valve regurgitation

Aortic Valve Stenosis

Aortic valve stenosis and regurgitation

Aortic valve thickening

Dilation of aortic root and/or ascending aorta; dissecting thoracic aortic aneurysms; aortic valve regurgitation

Connective tissue diseases

• Ankylosing spondylitis

• Churg–Strauss syndrome

• Behcet disease

• Ehlers–Danlos syndrome

• Takayasu vasculitis

• Primary antiphospholipid syndrome

• Systemic sclerosis

• Primary antiphospholipid syndrome-related bioprosthetic valve stenosis

• SLE

• Sjogren syndrome

• Rheumatoid arthritis

• Granulomatosis with polyangiitis

• Marfan’s syndrome

Table 2: Aortic valve changes in certain vasculitis

Name of vasculitis Takayasu arteritis Granulomatosis Churg–Strauss syndrome Behcet disease

with polyangiitis

Type of vasculitis

Large vessel arteritis

ANCA-associated small vessel vasculitis

Various vessel vasculitis

Aortic involvement

Aortic regurgitation

Aortic regurgitation (rarely aortic stenosis)

Mainly aortic regurgitation

Aortic regurgitation

Aneurysms

Pseudoaneurysms

Aortic rupture

Stenotic lesions (brachiocephalic artery)

Characteristic of aortic valve changes

• Secondary to dilation of the aortic root

• Normal valvular cusps in echocardiography shows

• Aneurysm can be present

• Thickened cusps of the aortic valve

• May be the only sign of relapse in GPA

• The onset: at the time of diagnosis or few years after diagnosis and correlates with elevated PR3-ANCA

• Chronic or acute manifestations (e.g., the perforation of the cusps of the aortic valve)

The valve is dense and thick due to fibrosis and the inflammatory reaction

Aortic regurgitation

• The most common valvular pathology

• Aneurysm

• Elongation and prolapse of aortic cusps

• Vegetation like lesions

Aortic valve regurgitation

• Can be secondary to aneurysm of the ascending aorta due to vasculitis

• Normal or fibrosed cusps of the valves

• Annulus dilatation

• Cusp fenestration and fusion

Histopathologic findings

• Disrupted elastic fibers in the media

• Granuloma

• Marked collagen deposition in the adventitial

• Granulomatous inflammation

• Polymorphonuclear microabscesses (differentiate with infective endocarditis)

• Foci of necrosis

• All findings located in the central layer of the valve

• Fibrosis and inflammation => dense and thick valve

• Valve leaflets infiltrated by eosinophils, lymphocytes and plasma cells

• Necrotizing granulomas

Lymphoplasmacytic infiltrates, neutrophils, histiocytes, eosinophils and occasional giant cells, myxoid degeneration, focal necrosis, and fibrotic thickening

Other causes include

Association with bicuspid aortic valve

Hypertension and Atherosclerosis

Other Contributing Factors

The Bentall Procedure

The Bentall procedure is performed when there is a combination of aortic valve disease, either stenosis or regurgitation, associated with a dilated aortic root. Aortic root aneurysms are one of the most common aortic root diseases, involving the aortic valve, aortic sinus, bilateral coronary arteries, and part of the ascending aorta. It is a life-threatening aortic disease with a high mortality rate of approximately 90%, due to aortic aneurysm rupture. Surgery is considered for aortic root diameters of 5.0 cm or greater in most cases. Specific conditions may include: Bicuspid aortic valve where surgery may be indicated at smaller diameters (4.5-5.0 cm) due to an increased risk of aortic dissection, in patients with Marfan syndrome surgery is recommended at 4.5-5.0 cm due to the rapid progression of aneurysms, for patients with familial aortopathy surgery may be considered at 4.0-4.5 cm depending on the specific genetic condition. Other factors that go into decision making include: a patients age, older patients may have a higher surgical risk, so surgery may be delayed until larger aneurysm sizes, comorbidities: Patients with other health conditions may have a higher risk of complications, which can influence the surgical decision, and the aortic area to height ratio can be used to assess the severity of the aneurysm and guide surgical timing.

There are a few options to managing the particular disease process. In some circumstances, the aortic valve disease can be attributed to the dilation of the aortic root. In this situation the valve can be saved and root repaired. The David procedure, also known as valve-sparing aortic root replacement, is a surgical technique used to treat aortic root aneurysms while preserving the native aortic valve. This procedure involves removing the damaged portion of the aorta and reimplanting the valve into a synthetic graft, which avoids the need for lifelong anticoagulation therapy. It is particularly beneficial for patients under age 75 with a healthy or repairable aortic valve and minimal calcification. The Yacoub procedure, developed by Sir Magdi Yacoub, is another valve-sparing technique that reshapes the sinotubular junction with a Dacron graft. It is designed to treat similar conditions as the David procedure but may differ in the method of graft attachment. Both procedures aim to enhance long-term heart health by preserving the native valve and reducing complications associated with mechanical valves.

The procedures that include aortic root and valve replacement are Bentall procedure and Cabral procedure. The Bentall procedure was developed in 1968 by Bentall and De Bono, this technique involves complete aortic root replacement using a composite graft that includes a mechanical or biological valve. The coronary arteries are reimplanted directly onto the graft, which can lead to complications such as bleeding and pseudoaneurysm formation at the anastomosis sites. Modified versions of the Bentall procedure have been developed to improve outcomes and reduce complications. The Cabrol procedure was introduced in 1981 by Cabrol, this technique uses a "moustache-shaped" interposition graft to connect the coronary ostia to the aortic graft. This method aims to create a tension-free anastomosis, particularly in cases where the anatomy is complex or when reoperations are necessary. The Cabrol procedure is often considered when the Bentall technique may not be suitable due to anatomical challenges. In this program I will describe the Bentall procedure.

Median sternotomy is performed in a majority of cases. You may be at an institution where surgeons employ minimally invasive techniques however, this is not commonly done in this fashion. The sternotomy is done in the usual standard fashion as described in prior discussions on this site. For details, please visit the Laying the Foundation page.

Following the sternotomy and exposure of the mediastinal structures some surgeons dissect the space under the aorta in preparation of partial or total removal of the ascending aorta depending on the extent of the aneurysmal area involved. Dissection of the aortic root will also be performed including isolation of the space near the right and left coronary arteries and the base of the root below the noncoronary, left coronary and right coronary cusps of the aortic valve identifying the root. This process is performed prior to or after the cannulation process. Cannulation for the Bentall procedure is the same used for aortic valve replacement, central aortic and right atrial venous. Depending on the extent of the aortic aneurysm circulatory arrest may be required. The addition of circulatory arrest will change the cannulation strategy slightly by adding a branch off the aortic cannula for antegrade cerebral perfusion. In addition to the aortic and venous cannulation, cannulas are also placed for antegrade and retrograde cardioplegia and left ventricular vent.

If not already complete and prior to instituting cardiopulmonary bypass (CPB) and cross clamping the process of dissecting out the aortic root may be performed. If there appears to be hemodynamic issues this may also be performed after instituting CPB. By completing the isolation of the aorta and root prior you minimize time on CPB and cross clamp.

For isolation of the aorta the assistant provide exposure by deflecting the aorta toward the assist side using your left hand or left-handed peanut while using suction with a yankower tip to keep the field dry (Figure 1a). The tissue between the aorta and pulmonary artery also needs to be separated. The assistant helps to facilitate this process by retracting the pulmonary artery using a DeBakey forceps while the surgeon retracts the aorta (Figure 1b). Remember to hold tissue directly across from the surgeon moving up or down as the surgeon moves. The remainder of the dissection around the root will occur once the patient is placed on CPB and the cross clamp is placed.

Figure 1a

Figure 1b

Following placement of the aortic and venous purse strings, cannulation proceeds in the usual fashion starting with the aortic and venous canulation (Figure 2a & b).

Figure 2a

Figure 2b

Placement of the retrograde (Figure 3a), antegrade (Figure 3b) and LV vent (Figure 3c) follow placement of the aortic and venous cannulas.

Figure 3a

Figure 3b

Figure 3c

Crossclamp is placed and the heart is arrested. Following the placement of the crossclamp the surgeon turns attention to preparing the aortic root for the procedure. In this case the surgeon opted to open the aorta prior to completing the dissection at the root and coronary ostia (Figure 4a & b). This technique allows for greater flexibility in isolating all the necessary structures. The freeing up of the left and right coronaries and dissecting the area at the base of the heart where the ventricle meets the beginning of the aorta is essential in making placement of the coronary ostia tension free and leaving enough tissue to sew the valve/conduit to the old root tissue.

Figure 4a

Figure 4b

Once the aorta is open the surgeon will place retention sutures at the aortic commissures for exposure. These retention stitches will be essential for exposure of vital structures such as the aortic root as the procedure progresses (Figure 5).

Figure 5

As the surgeon prepares the aortic root the assistant needs to focus on retracting tissue adjacent to the specific structures. This is the area where the left ventricular muscle transitions to the aortic tissue. The main reason for completing the root isolation is to define the demarcation between ventricular muscle and aortic tissue. Enough aortic tissue needs to be left behind in order to have enough space for the valve sutures. This is typically achieved by leaving the bottom of the two coronary and the noncoronary sinuses intact. It is not unusual to see ventricular muscle when performing this isolation. Due to hemodynamic concerns this process may need to be performed following the institution of CPB. In this video a majority of the dissection at the root and around the aorta is occurring after the cross clamp is on and heart arrested. This particular patient had significant aortic valve insufficiency making it prohibitive to arrest the heart using antegrade cardioplegia. The heart was arrested with retrograde initially. The aorta was open and the coronaries perfused directly for adequate protection.

With the noncoronary cusp the assistant needs to retract the aorta towards the assist side. On the right side the assistant is retracting the aorta back so the surgeon can dissect the base of the noncoronary cusp. Note that the retention suture from the left and non cusps is pulled toward the assistant to assist with exposure (Figure 6a). The surgeon may frequently check the opposite side of the dissection into the inside of the aorta to confirm the location of the nadir of the noncoronary cusp (Figure 6b).

Figure 6a

Figure 6b

Following the isolation of the noncoronary cusp portion of the aorta the portion of the sinus is removed beginning along the right and non cusps cutting down to the nadir of the valve (Figure 7a), then along the left and non cusps cutting down to the nadir of the valve (Figure 7b). Note that in figure 7a the assistant is creating slight counter traction using a DeBakey forceps pulling the aorta opposite to the surgeon. In figure 7b the assistant is holding the segment to be removed aiding in exposure and slight traction facilitating the excision of the tissue.

Figure 7a

Figure 7b

The surgeon then progresses to the right coronary cusp. As the assistant you can facilitate this process by retracting the fat adjacent to the RVOT and aorta. This tissue is very fragile, so manipulation has to be done carefully. As with the noncoronary cusp you will need to move along with the surgeon, so your tension is directly across from you (Figure 8a & b). Also Keep in mind there is a very important structure in this area, the right coronary. It arises from the middle of the right cusp and exiting shortly from its origin slightly towards the surgeon side to the cautery device in figure 8b. That is why the surgeon may go back and forth between outside and inside of the aorta to clearly define where the right coronary comes out.

Figure 8b

Figure 8b

Following the isolation of the right cusp portion of the aorta the right coronary button is created. This begins by cutting along the right and non cusps staying clear of the right coronary (figure 9a). Note that a fair amount of tissue remains that will be trimmed down later. The other side of the of the button is created along the right and left cusp cutting down to the nadir of the valve (Figure 9b), Note that in figure 9a the assistant is creating slight counter traction using a DeBakey forceps pulling RVOT fat adjacent to the area the surgeon is dissecting. Also note in figure 9b the retention suture is directed toward the surgeon holding the aorta away creating better exposure.

Figure 9a

Figure 9b

In order for the coronary buttons to work properly, the surgeon needs to take some time to isolate the base of the button so there is enough mobility to attach the button to the graft without kinking. (Figure 10a & b)

Figure 10a

Figure 10b

A brief comment about myocardial protection. Although there is a cannula in the coronary sinus for retrograde perfusion, right ventricular protection is always an issue. In an effort to minimize this problem surgeons tend for give cardioplegia via the right coronary directly. This can either be done by manually holding a perfusing cannula in the ostia (Figure 11a), or as in this case, a purse string is placed around the right coronary button. A soft tipped cannula is inserted and held in place using the tourniquet. (Figure 11b)

Figure 11a

Figure 11b

Prior to creating the left coronary button, the valve leaflets are removed from left to right starting with the noncoronary cusp followed by the right cusp then the left cusp. During this process the only responsibility the assistant has is to maintain a dry field. In this case the far-right image shows the assistant using a fin tip suction.

Following removal of the aortic valve leaflets the surgeon will take the opportunity to size the annulus for the valve/conduit composite (Figure 12a & B). This particular patient is having a tissue valve placed with the sizer having two sides. One measures the diameter of the anulus in comparison to the size of the valve (Figure 12a). The other is a replica sizer used to confirm the fit and predict how well a prosthetic valve will seal, especially with calcified valves. (Figure 12b).

Figure 12a

Figure 12b

The last button isolated is the left coronary button. As before the assistant will hold counter traction on the adjacent tissue opposite the surgeon. In this case it is the pulmonary artery. Just prior to cross clamping the space between the PA and Aorta was mostly dissected however some of the tissue cannot be dissected until the aorta has been transected (Figure 13). Typically, the left coronary artery exits the aorta above the middle of the left coronary sinus and traverses along the heart below the pulmonary artery. As the surgeon dissects out the posterior tissue great care needs to be taken to avoid getting into the vessel. That is why you will see the surgeon constantly looking in the aorta to confirm the location in relation to the dissection.

Figure 13

Aside from the complexities of dissecting the left coronary the creation of the button is performed in the same fashion as the right button. The initial cut is along the right and left commissure. At this point the retention suture is maintaining exposure so the main responsibility for the assistant is maintaining a dry field. Just as with aortic valve replacements, the most notable thing is the constant blood return via the left coronary. During the process of isolating the left coronary button one of the main responsibilities is to control this issue. I find it is best done by keeping the fine tip suction just above the left coronary ostia. This will take care of all the bleeding issue. One important point to remember, do not put the suction in the ostia. This may result in injury to the vessel. (Figure 14)

Figure 13

Once the isolation in the left/right commissure is mostly complete the surgeon will move to the left/non commissure and move down towards the nadir of the left coronary cusp (Figure 14a). At this point the surgeon may go back and forth to either side to get an even dissection to isolate and free up the button for maximal mobility for the graft anastomosis (Figure 14b & c). This is where you have to use judgement as an assistant. Holding and directing tissue to improve exposure and suctioning to keep the field dry. In these three images you will notice different things that are being done to facilitate the process. In figure 14a I am doing nothing at all. This is just as important. Intervening when you don't need to can be just as bad as doing nothing. In image 14b I am retracting the right/left commissure for exposure. Note I am holding the suction but not using it because it is not necessary. In 14c I am deflecting the coronary button to the left to expose the lower end of the button. At the same time, I am hovering over the left coronary ostia keeping the field dry. Figure 14d shows the left and right coronary buttons ready for anastomosis.

Figure 14a

Figure 14c

Figure 14b

Figure 14d

Now that the valve leaflets have been removed, annulus sized with associated valve/graft size chosen and coronary buttons created the surgeon can turn attention to placement of the valve/graft conduit. The first step in this process is placement of the valve sutures. The same sutures as this standard valve placement are used. Valve sutures come in two colors white and green and are double armed meaning a needle is attached at both ends of the suture. Each suture has a pledget, a small piece of fabric or tissue so that the suture will not tear through the tissue. Organization and order of the sutures is crucial. The colors are alternated so the pairs stay separate and easily identified. If the sutures get mixed up the valve/graft will not seat properly. As with anything in cardiac surgery every surgeon has a preference for the order with which sutures are placed. In this case the surgeon prefers to place the three commissure stitches first. The best way to assist with this process is to help with exposure and making sure the pledgets/sutures are not twisted. Exposure is not as difficult in this circumstance since the entire aorta is missing making suture placement quite simple. Since the coronary ostia are separated from the aorta the issue of bleeding in the field is reduced as well (Figure 15)

Figure 15: From left to right non/left commissure, left/right commissure, right/non commissure

The valve sutures are now placed in the standard fashion according to the surgeon's preference. As the assistant your responsibilities remain the same. Maintaining a dry field, ensuring good pledget placement, assisting with pledget placement as necessary and helping to keep all sutures organized. Even though things are a bit easier there are still things you can do to assist with exposure to facilitate the process. Even with the aorta removed the anulus still maintains its native curved shape. Placing stitches is easier if the curve is straightened out. Figure 16a is attempting to place a stitch with the curve. In figure 16b the assistant is pushing the left/right commissure which straitens out the annulus making exposure better and improving the ability to make an accurate suture placement. Use this type of exposure technique for the left coronary suture placement.

Figure 16a

Figure 16b

When switching to the right coronary cusp suture placement I find retracting the remnant of the aorta using a DeBakey forceps works well as in figure 17. Yes, I know, the changes are subtile but that is really all it takes.

Figure 17: Image on left is without exposure. Image on the right is with exposure.

For the noncoronary cusp exposure is not really an issue. Primarily all you need to do is hold tension on the 2 limbs and the surgeon uses that tension to manipulate the suture straightening out the annulus. Figure 18a is prior to the surgeon retracting the suture over. Figure 18b is with the surgeon retracting the suture.

Figure 18a

Figure 18b

Typically sutures for aortic valve replacements have small pieces of felt called pledgets. Pledgets are small patches or felt-like materials used in surgical procedures to reinforce sutures and prevent tissue tearing. They are particularly useful in situations where the tissue being sutured is fragile or where there is a risk of the sutures pulling through the tissue. Pledgets help distribute the tension of the sutures over a larger area, thereby enhancing the stability of the repair. Valve sutures tend to twist when placed and if the twist is not undone the pledget will not sit properly which results in the valve not seating properly causing a perivalvular leak or in this case, since there is no longer an aorta, significant bleeding. One of the most helpful things you can do to facilitate suture placement is manipulate the pledgets so they land flat. If done correctly this simple task can actually facilitate the process of placing the valve sutures.

Tricks of the trade managing pledgets: There are techniques I like to use to facilitate pledget placement. Due to location, the need for surgeon access and assistant positioning each technique has a specific place. The first technique is used primarily for the suture placement in the left coronary cusp. As described above each valve suture is double loaded. The suture is placed as a pair one end enters the annulus and is pulled through then the second end advances and inters the annulus a few millimeters from the last and is pulled through. As the two ends are pulled up the pledget is pulled down to the underside of the annulus. Before the loop is closed and the pledget I place a Debakey forceps through the loop and part the ends. This process unwinds and twists in the suture as the pledget is pulled into place. After the pledget is in place I remove the forceps. The second technique is more suitable for the noncoronary cusp although I will use the first and second technique interchangeably with the right coronary cusp as well. With the second technique, following the first bit you will take the 2 limbs created, the one the just went through the annulus and the limb of the second suture just before it goes through. It is key to not take too much suture, so the surgeon has plenty of length to make the second bite. While the surgeon is taking the second bite you grab the pledget with the Debakey forceps and as the surgeon brings up the second limb of the suture you ease the pledget down into place. The video below demonstrates both techniques.

Now that all the sutures have been placed (figure 19a), the surgeon will turn attention to placing the sutures in the valve/graft composite. The valve graft conduit consists of a 30 mm Hemashield graft with artificial sinuses, and, in this case, a 25 mm Edwards pericardial valve incorporated into the base of the graft (figure 19b). The valve/graft composite it sewn to the aortic root in the same manner a standard valve is placed. The main difference being there is no aorta around the valve so if there is a perivalvular leak it will be into the pericardial space not contained within the aorta.

Figure 19a

Figure 19b

The sutures are placed just as they would be on a standard aortic valve replacement. The order in which the sutures are placed is surgeon specific. In this case the surgeon is starting with the noncoronary cusp (figure 20a). One of the most important things to consider when positioning the sutures is the location of the of the nadir of the artificial valve for the left and right coronary buttons. Artificial tissue valves have posts that mimic the commissures. The pericardial leaflets are sewn to the posts and sewing ring to form a structure similar to a native valve. The valve/graft composite are made with black lines indicating the location of the posts (figure 20b).

Figure 20a

Figure 20b

The sutures to be place are divided into 3 areas related to each cusp. Before the sutures are placed it is important to know how many stitches there are in total and in each of the three quadrants. As the surgeon progresses with placing stitches it is the assistant's responsibility to keep track of how many sutures are left in each quadrant. If you notice there is more space than sutures left on a particular quadrant you need to remind the surgeon how many sutures are left. Same goes for too little space and too many stitches. In figure 21 below you can see all 3 quadrants separated.

Non Cusp

Left Cusp

Right Cusp

Figure 21

With all the sutures placed through the valve annulus the valve is ready to be parachuted down. For this process the assistant takes the right and left cusp sutures while the surgeon takes the noncusp sutures and the valve. Each set of valve sutures are held parallel to the valve as it is placed. The scrub will also saturate the sutures with saline making it easier to slide down (figure 22a & b).

Figure 22a

Figure 22b

Once the valve is down to the annulus some surgeons opt to seat the valve at three points at the nadir of each valve cusp using tourniquets. (figure 23)

Figure 23: From left to right tourniquet to non cusp, tourniquet to left cusp, tourniquet to right cusp

Prior to tying the sutures, the positioning tool is removed (figure 24a) and graft shortened (figure 24b). By shortening the graft tying the sutures is easier.

Figure 24a

Figure 24b

Once the valve is seated the surgeon will tie the sutures. The pattern used is surgeon specific. In this case the surgeon is tying each cusp starting with the left cusp to the right cusp and finally the non cusp saving the three tourniquet sutures for last.

Tricks of the trade - Suture mobility: Prior to tying any suture anchoring a valve you need to check to be sure both limbs move by sliding then back and forth. There are several reasons for doing this.

First of all, even though the pairs of stitches alternate in color from green to white, there are cases where the same color grouping is adjacent to each other. By moving the limbs, you can be assured both limbs belong to the same stitch (figure 25).

Pair of white stitches together

Figure 25

Secondly, when sutures are placed the prior adjacent stitch is close. Occasionally the surgeon captures the neighboring inadvertently sewing through the adjacent stitch also known as William Telling the stitch, named after the famous tale of William Tell shouting an arrow through an apple on his son's head. When this happens, the suture will not move and cannot be tied since it will not be tight. Sorry, no example of the yet, it's kind of rare but very important to catch.

Last consideration for moving and pulling up on the sutures is to be sure any slack that may have occurred during the seating process has been resolved. Again, if the slack remains after the knot is tied the valve will not seat completely resulting in a leak.

Each group of sutures is contained using a straight snap. When a group of sutures is prepared to be tied the snap is removed, the sutures separated and tied. To facilitate this process the assistant keeps the sutures organized and prepares the next suture in line (figure 29a), so it is ready for the surgeon by separating the two limbs (figure 26b), and pulling on the ends as described above. When the suture is tied the assistant will hand the next one to the surgeon and then moves on the next suture repeating the process. The sutures with the tourniquets are tied last (figure 26c).

Figure 26a

Two Limbs separated

Figure 26b

Figure 26c

Typically, once the sutures are placed the surgeon will turn attention to the coronary buttons. I this particular case the surgeon has opted to place a reinforcement stich around the annulus. When the procedure is complete and the patient is weaned of cardiopulmonary bypass the aortic root is essentially inaccessible, especially in the posterior aspect. This is true for the left coronary button as well. If there is any bleeding it is unlikely to be repairable without going back on bypass and cross clamping the heart again. Even with that the access to the posterior aspect is extremely difficult. The most important purpose for this suture is to reinforce the annulus and valve/graft conduit as an extra support to prevent disruption and bleeding. A 4-0 proline is used in a running fashion around the entire anulus using the remanent of the native aorta sewn to and around the valve/conduit ring (figures 27a & b).

Figure 27a

Figure 27b

The assistant facilitates this process by keeping the field dry with intermittent suctioning using a fine tip suction, following the suture keeping a tight suture line, and helping with exposure by manipulating the tissue adjacent to the native aorta or the graft (figure 28a & b).

Figure 28a

Figure 28b

After the annulus has been reenforced the surgeon turns attention to the coronary buttons. The left button is first since it is a posterior structure and requires the most amount of access and visibility. As with the aortic annulus this structure will not be accessible once the cross clamp is off and the patient comes off cardiopulmonary bypass. Therefore, meticulous care and attention must be paid to this anastomosis.

Tips of the trade - Coronary Buttons: Coronary button quality can vary from patient to patient. Disease processes are not isolated to the areas you are working. Calcification of the aorta and associated structures including coronaries and branching vessels such as the carotid arteries can be scattered and diffuse often time in random patterns. When this includes the coronary ostia and buttons the anastomosis can be very challenging. In this case it was not an issue however, the disease related to this procedure results in dilation and thinning out of the aorta which makes the tissue very thin. This is why the surgeon will typically us some kind of support device when performing the anastomosis. This usually takes the form of ether a strip of felt or, in this case felt cut like a donut where it is slipped over the button (figure 29a & b) and rests around the coronary ostia (figure 29c). As the assistant you are responsible for helping to manipulate the felt donut over the coronary button and into place. This can include manipulating the button to manipulating the felt. The felt will be included as part of the anastomosis with each bite.

Figure 29a

Figure 29b

Felt "donut"

Figure 29c

The coronary button will need a landing place on the aortic graft. This needs to be precisely measured in order to prevent kinking. If the coronary button has been freed sufficiently there will be some flexibility. In this case the surgeon is bending the graft toward the button while gently lifting the button (figure 30).

Figure 30

Once the location is defined pressure to the site from inside the graft is performed using a schnidt clamp while the site is marked on the outside (figure 31a & b).

Figure 31a

Figure 31b

Once the space is marked a hole is created in the graft use a heated pen that locally creates a high heat to melt the graft. The surgeon moves the device in a circular fashion creating a hole in the graft large enough to fit the coronary button, approximately 10-12 mm with the excised button cuff being approximately 15 mm (figure 32a & b). We frequently use a drop sucker hooked up as the pump suction seen in figure 32b. This does a majority of the suctioning limiting the assistant responsibility to minor fine suctioning primarily around the left coronary button.

Figure 32a

Figure 32b

The button is then sewn in place starting at the 5 O’clock position using a 5-0 proline suture using an outside in technique on the button. The anastomosis will continue clockwise going from inside out on the graft and outside in on the coronary button with the needle traversing the graft, felt strip and button. This process continues along the surgeon side. As the anastomosis continues the assistant is following the suture with the right hand and retracting the graft for exposure using a DeBakey forceps with the left hand (figure 33a & b). Note that the follow directs the suture away from where the needle will come out. When reaching about 10 O’clock on the surgeon’s side the direction changes and the surgeon will complete the anastomosis on the assistant side counterclockwise. The assistant’s responsibilities are the same for this part of the process.

Suture follow

Retracting graft

Figure 33a

Suture follow

Needle will come out here

Figure 33b

The process will continue clockwise up the surgeon's side until the extra tissue that is used to help with retraction (figure 33a above) is reached. Since the first part of the anastomosis started inside the graft to the outside of the button the opposite side of the anastomosis is performed from the inside of the button to the outside of the graft. As with the surgeon side of the anastomosis the assistant is responsible for exposure, keeping the suture line tight and following the suture directing the suture away from where the needle comes out (figure 34a & b).

Figure 34a

Figure 34b

As the surgeon approaches the extra tissue section again a pause is taken as the button is sized down to the final configuration to complete the anastomosis (figure 35a). The anastomosis is continued along the same way until it is completed. You will not as the anastomosis is coming to an end it becomes more difficult to see the inside of the graft and button. To facilitate the last 3-4 bites the assistant will need to relax on the suture follow and retract the graft. This will produce just enough space to ensure a good exposure to accurately place bites in the graft, felt and button (figure 35b).

Figure 35a

Relaxed Suture Follow

Space Created

Retraction of Graft

Figure 35b

Once the left coronary button has been completed the surgeon will turn attention to the right coronary button. determining placement of the right button is similar with one acceptation, the right coronary exits the aorta anteriorly and initially traverses along the anterior surface of the RV. Because the heart is empty when placing the right button, it is difficult to get an accurate location for placement (figure 36a). If the placement is determined with the heart empty the location will be too low and will kink when the heart fills. For this reason, the surgeon has the perfusionist fill the heart with will lift up the right coronary button giving it a more realistic position for determining placement (figure 36b).

Figure 36a - Heart is empty placement low

Figure 36b - Heart full, better location

Once the location is chosen the site is marked (figure 37a). Some surgeons may double check the location again by filling the heart and positioning the button prior to cutting the hole in the graft (figure 37b).

Figure 37a

Figure 37b

Just like the left button a felt "donut" is placed to reenforce the anastomosis (figure 38a). The hole in the graft is made using a heated pen as described for the left coronary button (figure 38b).

Figure 38a

Figure 38b

The anastomosis is completed in the same fashion as the left button. The surgeon will perform the first part of the anastomosis in a clockwise fashion. Due to the angle the first 4-5 bites can be difficult. As the assistant manipulation of the button and adjacent tissue is very important. In this case the surgeon is starting the bites inside out through the graft (figure 39a) to the outside in through the button (figure 39b). The assistant is holding the tongue of the button with a DeBakey forceps in using the left hand to facilitate the first bite in figure 39a. not seen clearly in 39a, the assistant is following the suture using the right hand seen better in 39b.

Figure 39a

Figure 39b

As the surgeon makes the turn going clockwise with the anastomosis the assistant continues to help with exposure retracting adjacent tissue or the button and suture manipulation, always remembering to direct the suture away from where the needle exits and maintaining 50/50 length on the suture to avoid large loops that can get tangled (figure 40a & b).

Suture follow

Figure 40a

Deflecting button down

Figure 40b

As the surgeon reaches the tongue of extra tissue the anastomosis moved to the assistant side and the anastomosis is finished in a clockwise fashion. At this point the surgeon may look inside the graft to see if there are any abnormalities to with any of the suture bites requiring reinforcement. In this particular case there were none. The surgeon picks up from the 5 o'clock position where the initial bites were taken. The manner in which the remainder of this anastomosis is performed changes to outside in the graft and inside out on the button (figure 41).

Figure 41 - Left, surgeon assessing the button for abnormalities, Middle, suture through graft outside in, Right, suture to the button inside out.

The process continues counterclockwise to the edge of the area of extra tissue. At this point the surgeon will finalize the size of the button by cutting the excess tissue off (figure 42).

Figure 42

As the anastomosis is completed you will note that the space for identifying the edge of the button and graft becomes less (figure 43a). This is the point where the assistant has to slightly relax on the suture while the surgeon retracts the graft, creating a space to identify a complete thickness bite in the button and graft (figures 43b).

Figure 43a

Figure 43b

Once the anastomosis is complete (figure 44a image of left and right buttons and aortic valve replacement). Note the coronary ostia are located where they should be, in the middle of the coronary cusps created for them. The graft is clamped and pressurized for two reasons. The first is to give antegrade cardiopledgia. The second and equally as important is to assess for bleeding from the coronary button anastomosis. As mentioned earlier the location of the buttons makes repair virtually impossible once the cross clamp is removed, especially the left button which will be a posterior structure (figure 44b).

Right Coronary

Left Coronary

Figure 44a

Figure 44b

Now that the coronary buttons have been completed it is time to turn attention to the graft to aorta anastomosis. There are two possible scenarios with this anastomosis. The first is slightly more complicated where the ascending aortic aneurysm extends to the arch or beyond. When this occurs, the patient will require deep hypothermic circulatory arrest (DHCA) where the body is cooled to 18 to 20 degrees Celsius, the heart lung machine is turned off and the cross clamp removed. The anastomosis is completed within in a limited amount of time, typically 20-30 minutes. There are more details regarding DHCA in the aortic surgery page of this website. The second scenario is more straight forward, where the anastomosis is performed with cross clamp on as in this case. The first step is to get a general idea of the graft length and removal of the remaining part of the aneurysm section of the aorta (figure 45a & b).

Figure 45a

Figure 45b

The final preparation is made one the aorta has been resected. An important property of these grafts is the ability to stretch. If the graft is not sized properly it will kink. The surgeon will stretch the graft to get the proper length. Once the proper length is determined the posterior aspect needs to be shortened to mimic the lesser curve of the aorta (figure 46a & b). Anatomically the anterior aspect of the aorta is longer than the posterior aspect. If this differential is not appreciated and adjusted for the graft will kink.

Figure 46a

Figure 46b

Once the graft has been sized it is time to turn attention to the anastomosis. As this proceeds it is important to keep in mind as the potential for graft aorta miss match. This is created by the bevel made to mimic the lesser curvature of the posterior aspect of the aorta. The first 2 to 3 bites occur with the graft and aorta slightly separated. This gives the surgeon optimal exposure to get accurate bites at this vital location (figure 47a). The graft is then brought down to the aorta with the anastomosis continuing clockwise using the inside out technique to the graft and outside into the aorta (figure 47b). During this early process the assistant facilitates the process by following the suture and manipulating the graft.

Figure 47a

Figure 47b

Following the first 3 bites the graft is approximated to the aorta. The surgeon will continue in a clockwise fashion. During this process the assistant follows with the right hand and intermittently retracts the graft for exposure using a DeBakey forceps.

Tricks of the Trade - Directing the Suture. As the surgeon comes up the surgeon side of the anastomosis, you will notice in the images below, the assistant needs to alter the follow from toward the aorta when the needle goes through the graft (figure 48a) to toward the graft when the needle goes through the aorta (figure 48b). This directs the suture away from the exit site of the needle making it easier for the surgeon to grasp the needle and continue to the next bite. This process continues to about 10 o'clock on the anastomosis.

Needle going through graft

Suture follow towards aorta

Figure 48a

Needle going to go through aorta here

Suture follow towards graft

Figure 48b

Once the surgeon reaches the 10 o'clock spot and prior to switching sides to complete the anastomosis some surgeons like to reinforce the inferior aspect of the aorta with pledgeted sutures (figure 49a & b). Just as with the left coronary button, once the anastomosis is complete and the cross clamp is off this location is very difficult to repair. The reinforcing sutures help to avoid this issue.

Figure 49a

Figure 49b

Following placement of the reinforcement stitches the surgeon will begin with the assistant's side of the anastomosis sewing in a counterclockwise direction using the outside in technique on the graft and inside out technique on the aorta. The assistant will continue to follow using the left hand and retract the aorta using the left hand as needed to facilitate the exposure for a quality suture placement. Notice the follow is maintained toward the graft for the remainder of the anastomosis (figure 50).

Figure 50

Trick of the Trade - Suture Management. As the graft begins to approximate to the aorta the best way to get good exposure is to relax on the suture and retract the aorta with each bite (figure 51a). As each bite completes pull the suture tight (figure 51b). As the next bite goes through the graft relax on the suture and retract on the aorta. The idea is to maintain a tight suture line between bites. Keep in mind, the relaxation on the suture is very slight as is the retraction on the aorta, just enough to get good exposure.

Figure 51a

Figure 51b

The next consideration as the anastomosis progresses is the graft aorta miss mach potential. You may have noticed there is a noticeable miss match from the beginning due to a bevel needed to give the graft a proper curve to match a native aorta. It falls upon the surgeon and the assistant to keep an eye on this miss match (figure 52a & b). The degree of miss match can be adjusted over the entire anastomotic process however the ability to make corrections decreases as the final run up the assistant side begins. Corrections typically take the form of bites sizes where the travel along the graft is larger than the travel along the aorta.

Figure 52a

Figure 52b

As the anastomosis approaches the anterior portion of the aorta you can appreciate the difference between the graft and the aorta in figure 53a. As the anastomosis progresses to the end the surgeon switched direction and sews from the surgeon side using a horizontal mattress stitch in figure 53b. This type of suture technique can help close a small amount difference that is present. The tie at the end will cover the small defect remaining.

Figure 52a

Figure 53b