CHICAGO – European data suggest that minimally invasive aortic valve surgery has several benefits and few downsides when compared to conventional aortic valve replacement.
Bleeding is decreased, as is ICU and hospital length of stay. Cosmesis is improved. Sutureless valves may facilitate the performance of minimally invasive aortic valve replacement (AVR), and are associated with decreased ischemic times and lower transvalvular gradients – an advantage when concomitant procedures are performed or patients are high risk, according to a presentation at the 2012 Heart Valve summit.
Sutureless aortic valves facilitate minimal basic AVR and minimize myocardial ischemic time, said Dr. Michael Borger of Leipzig (Germany) Heart Center.
He described the evidence to date, as well as his personal experience, at this educational program of the American Association for Thoracic Surgery (AATS) and the American College of Cardiology Foundation (ACCF).
Leipzig Heart Center is one of Europe’s largest cardiac facilities, with 4,000 cardiac operations per year.
The number of patients who undergo minimally invasive aortic valve procedures is still very low, said Dr. Borger, and he urged the audience to consider this option in the future, especially when transcatheter aortic valve implantation (TAVI) becomes as widely accepted in America as it is in Europe. In Germany alone, 31% of isolated AVRs are now done by TAVI.
"Decreased myocardial ischemic time doesn’t matter for someone who needs an isolated aortic valve, [such as a] 70-year-old patient with no risk factors. It doesn’t matter if you shorten their ischemic time by 20 minutes. That’s not the point. The point is that a sutureless valve facilitates minimally invasive surgery by making it easier to do; and a marker for that is decreased ischemic time."
One subgroup of patients who do benefit from decreased ischemic times, however, are those requiring complex multivalve procedures. Patients who have a poor ejection fraction also benefit.
"We are applying lessons that we’ve learned from TAVI to these sutureless valves," said Dr. Borger. "TAVI has been in Europe – transfemoral for 10 years, transapical for 6 years – and what we know from TAVI is that a stent is able to hold an aortic valve in the left ventricular outflow tract and prevent it from embolizing afterwards. In addition, we now know that you do not need to fully decalcify the annulus. As a matter of fact, you’re better off leaving some calcification in the annulus when implanting sutureless valves ... to avoid the formation of annular tears or defects."
There are two approaches: the upper hemisternotomy approach, which is favored in Leipzig, and the upper right midlateral thoracotomy approach.
Three sutureless valves are currently in use in Europe: the Medtronic (formerly ATS) Enable sutureless valve, the Sorin Perceval S sutureless valve, and the Edwards Intuity valve.
The Medtronic Enable valve is equine pericardium and was the first sutureless valve to get CE mark approval in Europe. The literature is limited, but a study from Switzerland (J. Thorac. Cardiovasc. Surg. 2010;140:313-6) of the 3f Enable valve in 28 patients showed that the valve could be implanted safely and quickly with favorable early hemodynamics.
"Again, I just want to stress, the goal is not to go from 60 minutes down to 40 minutes of ischemia; the goal is to facilitate a minimally invasive approach," said Dr. Borger. He noted that the hemodynamics were excellent for all three sutureless valves.
The second valve to receive CE mark approval in Europe was the Sorin Perceval S, at the beginning of 2012. It has a bovine pericardial leaflet, also attached to a Nitinol stent, and is crimped at the bedside. This results in an advantage for implantation.
"You can see exactly that the valve is in the position where you want it to be before deploying it," said Dr. Borger. The long-term results of crimping the leaflets are not yet known.
This particular model is currently available in sizes of 21, 23, and 25 mm. Even a 25-mm valve can only be put in a relatively small annulus, making the Perceval valve most appropriate for the small, elderly patient.
Sorin has reported results from 186 patients who received the Perceval valve, and noted short cross-clamp times (mean cross-clamp time for isolated AVR, 28.6 minutes) and 2.8% mortality.
The third and final sutureless aortic prosthesis is the Edwards Intuity valve, whose top is a traditional design based on the Magna Ease valve, and whose bottom is stent technology borrowed from Edwards’ TAVI program. A recent study of 152 patents revealed an average cross-clamp time of 41 minutes for isolated AVR, with a perioperative mortality rate of 2.1% and a paravalvular leak rate of 1.4% (J. Thorac. Cardiovasc. Surg. 2012;145:110-16). In addition, hemodynamics were excellent, with a mean transvalvular gradient of 9.8 mm Hg.