The first North American experience with a sutureless bioprosthetic aortic valve that has been available in Europe since 2005 and is well suited for minimally invasive surgery has underscored the utility of the device as an alternative to conventional aortic valve replacement (AVR) in higher-risk patients, investigators from McGill University Health Center in Montreal reported in the March issue of the Journal of Thoracic and Cardiovascular Surgery (2016;151:735-742).
The investigators, led by Dr. Benoir de Varennes, reported on their experience implanting the Enable valve (Medtronic, Minneapolis) in 63 patients between August 2012 and October 2014. “The enable bioprosthesis is an acceptable alternative to conventional aortic valve replacement in higher-risk patients,” Dr. de Varennes and colleagues said. “The early hemodynamic performance seems favorable.” Their findings were first presented at the 95th annual meeting of the American Association for Thoracic Surgery in April 2015 in Seattle. A video of the presentation is available.
The Enable valve has been the subject of four European studies with 429 patients. It received its CE Mark in Europe in 2009, but is not yet commercially approved in the United States.
In the McGill study, one patient died within 30 days of receiving the valve and two died after 30 days, but none of the deaths were valve related. Four patients (6.3%) required revision during the implantation operation, and one patient required reoperation for early migration. Peak and mean gradients after surgery were 17 mm Hg and 9 mm Hg, respectively. Three patients had reported complications: Two (3.1%) required a pacemaker and one (1.6%) had a heart attack. Mean follow-up was 10 months.
Patient ages ranged from 57 to 89 years, with an average age of 80. Before surgery, all patients had calcific aortic stenosis, 43 (68%) had some degree of associated aortic regurgitation, and 46 (73%) were in New York Heart Association (NYHA) class III or IV. At the last follow-up after surgery, 61 patients (97%) were in NYHA class I.
The investigators implanted the valve through a full sternotomy or a partial upper sternotomy into the fourth intercostal space, and they used perioperative transesophageal echocardiography in all patients. They performed high-transverse aortotomy and completely excised the native valve.
The average cross-clamp time for the 30 patients who had isolated AVR was 44 minutes and 77 minutes for the 33 patients who had combined procedures. Dr. de Varennes and colleagues acknowledged the cross-clamp time for isolated AVR is “similar” to European series but “not very different” from recent reports on sutured AVR (J. Thorac. Cardiovasc. Surg. 2015;149:451-460). “This may be explained partly by the learning period of all three surgeons and the aggressive debridement of the annulus in all cases,” they said. “We think that, as further experience is gained, the clamp time will be further reduced, and this will benefit mostly higher-risk patients or those requiring concomitant procedures.”
They noted that some patients received the Enable prosthesis because of “hostile” aortas with extensive root calcification.
Dr. de Varennes disclosed he is a consultant for Medtronic and a proctor for Enable training. The coauthors had no relationships to disclose.