Author + information
- Evaldas Girdauskas, MD, PhD∗ ( and )
- Michael A. Borger, MD, PhD
- ↵∗Department of Cardiac Surgery, Central Hospital Bad Berka, Robert-Koch-Allee 9, 99437 Bad Berka, Germany.
We read with great interest the paper by Hardikar and Marwick (1) published in a recent issue of iJACC. The authors should be congratulated for their efforts to address the controversial issue of bicuspid aortic valve (BAV)–associated aortopathy in their current meta-analysis. This report is based on a systematic review of the published literature on BAV aortopathy, with a special focus on aortic-related events during long-term follow-up. The most important finding of this meta-analysis is the very low risk of adverse aortic events in patients with BAV disease, which is in contrast to the widespread perception that exists in the cardiovascular—and in particular the cardiac surgery—community. Indeed, some have even incorrectly equated this risk with that observed in patients with connective tissue disorders (e.g., Marfan syndrome). Hardikar and Marwick (1) were able to identify BAV patients that were at higher risk of aortic events, however, according to patients' age and clinical setting.
The major limitation of the aforementioned meta-analysis is the heterogeneity of the published literature on BAV-associated aortic disease. Such heterogeneity was partially addressed by means of stratification by stage of BAV disease (i.e., nonoperated vs. post-operative BAV patients). However, major heterogeneity also exists within the post-operative patients, as demonstrated by the highly significant I2 statistic (1). In our experience, this phenomenon may be explained by the fact that different forms of BAV disease (so-called BAV phenotypes) are frequently mixed together in published reports (2). The 2 distinct clinical entities of BAV disease, namely, BAV in patients presenting with predominant aortic valve stenosis and dilation of the supra-coronary aorta (i.e., BAV stenosis phenotype), and BAV in patients presenting with predominant aortic insufficiency and dilation of the proximal aortic root (i.e., BAV root phenotype), are characterized by major differences in the patterns and the prognosis of associated aortopathy (3,4). However, very few published studies to date have separately analyzed these 2 distinct patient subgroups.
Hardikar and Marwick (1) used the age of BAV patients as an additional clinical variable to stratify the outcomes of BAV-associated aortopathy. However, age may also be interpreted as an indirect marker of the different BAV phenotypes. Evidence of this can be found in the fact that BAV patients who required aortic root surgery for aortic regurgitation were in the 5th decade of life, whereas patients undergoing isolated aortic valve replacement for BAV stenosis were in their 6th decade. Such findings are also in line with previous reports showing that aortic root dilation with resultant aortic valve insufficiency (i.e., root phenotype) is predominantly found in young, male BAV patients and is associated with a genetic form of BAV-associated aortopathy (3,4).
The finding from Hardikar and Marwick (1) that aortic dimensions progress more rapidly with increasing age of BAV patients may be somewhat misleading and should be interpreted with a caution. The proposed correlation between the rate of aortic enlargement and increasing age may be explained by the fact that the 2 referenced reports by La Canna et al. (5) and Davies et al. (6) included patients with dilated BAV aortas only. It is generally accepted that diameters of already dilated aortas progress more rapidly; this, rather than just patient age, may account for the accelerated growth of the proximal aorta observed in these studies. The annual growth rate of aortic dimensions in distinct clinical phenotypes (i.e., BAV stenosis vs. root phenotype) would be of great clinical value and should be a focus of future studies.
With the literature that is currently available, it is very difficult to accurately define surgical thresholds for BAV-associated aortopathy, because most of the published studies consist of mixed BAV phenotype cohorts and different stages of BAV disease. We strongly recommend a more homogeneous phenotype-specific reporting of outcomes in BAV disease in future studies.
- American College of Cardiology Foundation
- Hardikar A.A.,
- Marwick T.H.
- Girdauskas E.,
- Disha K.,
- Borger M.A.,
- Kuntze T.
- Della Corte A.,
- Bancone C.,
- Quarto C.,
- et al.
- La Canna G.,
- Ficarra E.,
- Tsagalau E.,
- et al.