Breaking Dogma in Aortic Valve Replacement: The Nine Suture AVR Technique

This video demonstrates a suture placement technique for aortic valve replacement that breaks with tradition.

Traditionally, sutures are placed along the aortic annulus using a horizontal mattress technique, in which each pair of sutures are abutting the neighboring suture, usually within 1 mm of each other. The dogma taught is that having any gaps between these paired sutures would result in a paravalvular leak, so the closer, the better.

Additionally, pledgetted sutures have generally been the standard for valve replacement, although there are exceptions.

In this novel nine suture AVR technique, horizontal mattress sutures are placed along the annulus with a pledget-width gap between each suture set. This results in a distribution of the force of the sewing cuff onto the aortic annulus, preventing leaks between the sutures. A similar concept is used on the wheels of cars, where four or five lug nuts fasten the wheel to the car axle in a way that distributes the force evenly. In the nine suture AVR technique, no pledgets are used in the sutures, which helps maintain a wide open LVOT.

A more detailed look at the technique shows that the surgeons place the three commissural sutures first, then usually place two more paired sutures in the annulus of each sinus. Therefore, the sutures have a distance of 3 to 5 mm between each mattress suture, and 3 to 5 mm distance within each mattress suture.

At this point, placing the annular sutures through the sewing cuff follows the same pattern as placing the sutures through the annulus, with equal gaps between each mattress suture, just as the lug nuts on a wheel.

This video demonstrates two common scenarios: a stenotic valve and a regurgitant valve.

[Video]

The Surgery

First, a standard aortotomy, valve resection, and debridement were performed.

The three commissural sutures were placed first. The surgical team focused on the annulus at the noncoronary location for best visualization. A pledget-width gap was noted between the commissural suture and the first noncoronary annular suture. A pledget-width gap was also noted within each mattress suture. When placing these through the sewing cuff, the same pattern of gaps between and within sutures was important to distribute the force. The lack of pledgets helps maintain a wide open LVOT.

Next, an echocardiogram confirmed no paravalvular leak and low gradients. For the regurgitant valve, the annulus was noted to be quite large, at 30 mm in diameter. The valve was resected, and the same suture pattern was deployed. In these very large valves, sometimes a third mattress suture is required in each cusp, instead of the usual two.

Surgeons could then better visualize the suture placement with the gaps in the left coronary annulus. They noted how the nonpledgetted suture also kept the operation running efficiently without the worries of pledgets twisting or lying incorrectly.

Finally, the team confirmed that the suture spacing on the sewing cuff mirrored that of the sutures on the annulus and the echocardiogram showed no paravalvular leak and low gradients.

Technical Pearls and Pitfalls

Surgeons should be mindful of several important technical elements. First, aggressive decalcification of the annulus is important so that the annulus conforms nicely with the sewing cuff. This keeps the annulus compliant and acts like a gasket by sealing the annulus to the sewing cuff.

For a small aortic annulus, a root enlargement can be performed, and this technique still deployed successfully. For a large aortic annulus or a bicuspid valve, a third mattress suture may be needed in the noncoronary cusp. For very large valves, a third mattress suture may be needed in each annular section.

The benefits of nonpledgetted sutures versus pledgetted sutures include a lower risk of subvalvular stenosis with improved transvalvular gradients. When numerous pledgetted sutures are used, the aortic annulus may be downsized due to the pleating affect that each suture causes, resulting in a narrower circumference. This is why some surgeons size the aortic annulus before and after placing the annular sutures to ensure that the correct valve size is chosen.

Meanwhile, with a nine suture technique, there are no pledgets and there are fewer sutures, so this method may allow larger valves to be implanted. Placing these nonpledgetted sutures is also highly efficient and less worrisome than pledgets, which may twist. In addition, the lack of pledgets makes any reoperation much friendlier to the surgeon and uses less foreign material so there may be a lower chance of infection.

Reference

Beddermann, Christoph, and Hans G. Borst. "Comparison of two suture techniques and materials: relationship to perivalvular leaks after cardiac valve replacement." Cardiovascular Diseases 5.4 (1978): 354.