Aortic valve stenosis presenting with bicuspid aortic valve.Since 2005, cardiac surgeons at the
Center for Bicuspid Aortic Valve Diseases of the
Penn Aorta Center have specialized in bicuspid aortic valve repair.
Traditional aortic valve replacement options are limited, particularly for younger patients, for whom the options are less than ideal. Bioprosthetic valves often wear out in a decade or two. Mechanical valves bring a lifetime of burdensome anticoagulant use.
At Penn Medicine, the comprehensive aortic surgery program has introduced valve-sparing procedures to overcome these limitations and extend valve replacement options to younger patients and those with complex cases, including valves considered unsalvageable.
Helping younger patients and watching for stenosis and regurgitation with BAV
Bicuspid aortic valve (BAV) is the most common congenital heart condition, affecting about 1% to 2% of the general population. Patients needing initial BAV support are generally on the younger side for cardiovascular care—between 40 and 60 years of age—with some presenting even younger.
“Bicuspid valves carry a host of issues,” says Nimesh Desai, MD, PhD, a BAV repair specialist and Director of the Penn Aorta Center. “They can be associated with aortic aneurysms, they can leak, and they can become stenotic.” In addition, Dr. Desai observes, BAV deterioration has a progressive course as the affected population ages. “In the twenties and thirties, these individuals tend to have leaky bicuspid valves, and by the fifties and sixties, we’re seeing BAV failure.”
Moreover, BAV is a common cause of aortic insufficiency (AI) and aortic stenosis (AS). AI can lead to dangerous left ventricular (LV) remodeling, while AS can cause myocardial fibrosis, an accumulation of scar tissue at the myocardium. Some people with a BAV experience both AI and AS.
Recognizing the connection between BAV and aortic aneurysm
Another major challenge with bicuspid valves comes in the form of aortic disease. Up to 50% of BAV patients also have a thoracic aneurysm, likely from a combination of shared embryonic changes and a weakened aorta from unusual blood flow. Some aneurysms need treatment, even if the BAV does not warrant intervention. Others require evaluation and close monitoring.
The location of such aneurysms varies:
- Root, ascending aorta and arch: 45%
- Ascending aorta and arch: 28%
- Ascending only: 14%
- Root only (Marfan-like and most dangerous): 13%
Even if patients do not have an aneurysm at the time of BAV diagnosis, their risk for eventually developing one is 80 times greater than the general population. Up to 30% will develop an aneurysm within 10 to 20 years.
Using TEE and MR to evaluate BAV
Given the prevalence of BAV and the potential complications, transesophageal echocardiography (TEE) plays a crucial role. All patients with enlarged aortic sinuses or ascending aortas should have their aortic valves imaged, just as all patients with a BAV need their thoracic aortas examined. Evaluation is best done at a comprehensive aorta center.
Beyond confirming the presence of a BAV and taking aortic measurements, the Penn team uses TEE to assess valves for repairability by looking at the number of fenestrations, degree of calcification, and amount of asymmetry. The team then creates virtual 3D models from CT scans to plan repairs using software developed at Penn.
Penn specialists also use TEE to screen family members. Among patients, up to 9% of first-degree relatives also have a BAV, though not all the genetic variants responsible are known yet. Family members flagged by TEE screening can then get a care plan to protect their health, whether through monitoring or an intervention.
Other appropriate advanced imaging includes cardiac MR with 4D flow to evaluate any eccentric jets, a common feature of BAV and one that can make the classification of AI challenging. Cardiac MR can also track subtle LV changes and look at specific areas of the aortic wall.
“We have the ability to look at aortas in real-time,” Dr. Desai says.“We can actually image the stress that’s on the wall of the aorta to try and understand if there are reasons why that person might be at a unique risk or need further evaluation.”
Addressing the lifespan of BAV—the Ross procedure returns
While many Penn patients still need classic aortic valve replacement, valve repair is an option for a significant portion, particularly younger individuals with leaky (regurgitant) bicuspid valves, according to Dr. Desai.
For younger patients who do not want to face the invariable deterioration that attends bioprosthetic valves or the lifelong need for anticoagulants required of mechanical valves, the Penn Aorta Center has reintroduced the Ross procedure, an innovative surgery abandoned in the decades after its introduction following concerns about procedural complexity and concerns about duration of efficacy. The procedure replaces the damaged or stenotic aortic valve with that of the native pulmonic valve, which is then replaced with a bioprosthetic valve—a maneuver that turned out to be a lesson in irony in the early years of the procedure. Because the pulmonic valve wasn't designed to endure the hemodynamic forces of its aortic peer, it tended to warp and fail after the switch, resulting in a second surgery to replace it with a bioprosthetic or mechanical valve.
Discussing the recent history of the Ross in a recent interview, Penn cardiac surgeon Dr. Michael Ibrahim noted that surgeons didn’t fully understand these technical issues—concerns resolved in the few institutions that continued to perform the surgery. “The operation has been standardized, and it's no longer something we don't fully understand,” Dr. Ibrahim says. “I think we have a really good handle on the ingredients for a good long-term result.”
“The Ross is the only therapy that’s ever been shown to give someone who’s needed an aortic valve replacement a completely normal life expectancy,” says Dr. Desai. “People can go for 35 to 40 years after the procedure without a replacement.”
Dr.Desai notes that the Ross procedure is an optimal choice for younger patients, and that Penn’s innovations avoid root dilation, a previous Ross shortcoming. “It's much improved compared to what we did 20 years ago.”
For Older Patients
The issues particular to bioprothetic and mechanical valves for aortic valve replacement are not as burdensome for older patients as they might be for younger patients.
“The bioprosthetic valves typically wear out between ten and twenty years,” says Dr. Desai. “Mechanical valves require blood thinners for life, and these are difficult drugs to manage, but this is easier to do in older, less active individuals.”
Aortic valve repair is an option, as well, in some patients. Techniques include plication of extra leaflet length for the prolapsed segment; triangular resection for calcified, thickened raphe; and/or raphe release. Even if Penn surgeons do not need to replace the aortic root, they may tighten or reinforce the annulus, an extra step shown to make aortic valve repairs more durable.
“The ability to repair valves rather than just replace them adds another component to the breadth of care we’re able to provide at the Aorta Center,” Dr. Desai says. “We also have a great understanding of how to treat the aneurysmal component and have a very longitudinal approach that provides the care these patients need for life.”
Assessing success of Penn Center for Bicuspid Aortic Valve Diseases at the Penn Aorta Center
Each Penn BAV patient is encouraged to follow through with surveillance visits, whether they end up needing an intervention or not. Regular monitoring with imaging is critical for health and safety. The BAV center follows more than 1,000 patients nationwide at individualized intervals.
In addition, a review of data from 2002 to 2020 shows the Penn Aorta Center treated 1,556 patients with BAV disease. Of those:
- 984 received standalone aortic valve replacement because of regurgitation, stenosis or a combination
- 333 received a Bentall procedure or proximal aortic reconstruction
- 134 received primary leaflet repair, with some also needing ascending aorta replacement
- 105 received primary leaflet repair and root reimplantation
Among patients who have received BAV repair at Penn, results trend in a positive direction. At two years out, 98% of BAV patients undergoing valve repair and root replacement retain freedom from regurgitation. At the 10-year mark, 86% of these patients still avoid AR. Data also show low reoperation rates and effective left ventricular remodeling.
Additional Resources from the Penn Aorta Center