Page 55 - Read Online

Perezgrovas-Olaria et al. Vessel Plus 2023;7:10 https://dx.doi.org/10.20517/2574-1209.2022.54 Page 9 of 11

DISCUSSION
An increase in the use of bCVG has been reported in the last 20 years, even in patients below the
recommended cut-off age established by American and European guidelines [2,3,11-13] . This has been driven
largely by patient preference and the desire of the younger generations to avoid lifelong anticoagulation
[14]
with warfarin due to its associated risks and restrictions . Additionally, some patients may have a
perception that transcatheter aortic valve replacement may rescue them from further open-heart surgery.
This change in valve preference is concerning because it increases the risk of reoperation by two
mechanisms. First, the lifespan of the bCVG is reduced due to accelerated deterioration in younger patients,
and second, the increase in life expectancy results in a larger window for aortic valve graft failure to ensue .
[5]
The median age of patients that received a bCVG in our cohort was 64 years old, slightly below the 65-year
cut-off established by European and American guidelines .
[2,3]

Studies have reported lower mortality rates for patients receiving mCVG compared to bCVG for isolated
aortic valve replacement [15,16] . When looking only at Bentall-De Bono cohorts, results are mixed. In a study
by Svensson et al. including 453 patients that underwent a Bentall-De Bono operation either with a mCVG
or bCVG, the authors found a higher 15-year mortality rate in patients with bCVG (57% vs. 26%,
P < 0.0001), which was attributed to a higher prevalence of comorbidities and older age in that group .
[17]
Conversely, Etz et al. found a slightly higher mortality rate in Bentall-De Bono patients with mCVG at
10 years after the procedure, although the difference was not significant (25% vs. 20%, P = 0.84) . In our
[18]
study, we observed a higher mortality rate in patients with mCVG, which became apparent approximately
6 years after surgery and could be partially explained by patients’ baseline characteristics. Although patients
receiving mCVG were younger, 33.3% were urgent or emergent procedures and 19.2% were acute aortic
dissections. This was partly due to a preference to use a prefabricated graft in patients with acute aortic
dissection earlier in the series. Additionally, a significantly larger proportion of patients had connective
tissue disorders (17.7%) and a third of the procedures were reoperations. While in most series, the bCVG
patients are older and higher-risk, in our series, the mCVG patients comprised the higher-risk group due to
their high-acuity clinical presentations.

At high-volume centers focusing on aortic root surgery, excellent results can be reliably reproduced. In our
series, operative mortality was low for all patients (0.4% vs. 1.2%; P = 0.18) and the incidence of all
individual postoperative complications was less than 1% except for re-exploration for hemorrhage, which
was required in 4% of patients. Despite the higher risk preoperative profile of the mCVG group, operative
outcomes were equivalent. The incidence of a composite outcome of MAE was only 6.2%.

Often, mCVGs are recommended to younger patients in order to reduce the risk of reoperation. In older
patients, bCVG is often preferred since the valve is likely to last the patient’s lifetime and the risk of needing
reoperation for structural valve degeneration is low. In a study conducted by Kyto et al., including 2,928
aortic valve replacements, the risk of reoperation was significantly lower for patients with mCVG (HR 0.30,
95%CI: [0.12-0.74], P = 0.009) . In Bentall-De Bono patients, Pantaleo et al. reported no significantly
[19]
different 7-year reoperation rate for mCVG and bCVG, albeit the trend favored the mCVG group (0.9% vs.
7%, log-rank P = 0.07) . In the present study, the 10-year reoperation rate of 1.1% in mCVG is consistent
[20]
with the generally believed notion that mechanical valves should last a lifetime, except for rare cases. The
10-year reoperation rate of 7.4% for bCVG is also reasonable since a majority of these are placed in older
patients, who may not outlive the lifespan of the valve. The higher need for reoperation in bCVG patients
became evident approximately 7.5 years after surgery.