Aortic Distensibility in Patients With Bicuspid Aortic Valves

READERS’ COMMENTS Aortic Distensibility in Patients With Bicuspid Aortic Valves We read with great interest Schaefer et al’s1 report “Usefulness of Bicuspid Aortic Valve Phenotype to Predict Elastic Properties of the Ascending Aorta,” and we congratulate the investigators on their intriguing study. The investigators demonstrated reduced aortic wall elasticity in patients with bicuspid aortic valves (BAVs). However, we believe that a few additional comments are necessary. In recent studies, it has been confirmed that aortic elasticity is frequently impaired in patients with BAVs.1–5 As suggested previously, BAVs should be considered a disease of the entire aortic root.3,6 The intrinsic pathology of the aortic wall in patients with BAVs has been reported because of accelerated degeneration of the aortic media. Inadequate production of fibrillin-1 during valvulogenesis may disrupt the formation of the aortic cusps, resulting in a bicuspid valve and a weakened aortic root.3 Moreover, differences in aortic elasticity among different BAV phenotypes have been described.1 Subjects with anterior-posterior leaflet orientation compared with those with right-left leaflet orientation had increased aortic stiffness at the sinuses of Valsalva but no difference in stiffness at the ascending aorta and aortic arch.1 Nistri et al4 found that the ascending aortas of patients with BAVs with aortic regurgitation were more distensible and less stiff than those of subjects with normally functioning BAVs. In contrast, Grotenhuis et al3 demonstrated reduced aortic wall elasticity in patients with BAVs, which was associated with the severity of aortic regurgitation and left ventricular hypertrophy. It has also been demonstrated that congenital aortic valve stenosis (AS) results in abnormal aortic elastic properties, independent of stenosis severity.5 As an analogy, we previously reported increased aortic stiffness in patients with AS without coronary artery disease, to a level comparable with that found in patients with coronary artery disease without valvular heart disease.7 This finding supported the suggestion that decreased aortic distensibility in AS can be an early manifestation of the atherosclerotic process (endothelial dysfunction), decreased perfusion of the aorta, or other factors

beyond physical pressure effects. Barbetseas et al8 found that aortic valve replacement (AVR) with a mechanical valve resulted in a significant decrease in aortic distensibility 1 week after AVR. However, it was a transient effect: 6 months postoperatively, aortic function had ameliorated. This was explained as AVR-induced transient trauma to the arterial wall, so-called aortic root stunning.8 In a longterm follow-up study, progressive reduction in aortic stiffness index was demonstrated, to levels comparable with those in controls matched on age, gender, and risk factors at 1-year follow-up.9 One of the possible explanations for improvement in vascular elasticity may be the recovery of damaged aortic root endothelium or pressure changes in the proximal aorta. In another study, aortic full root replacement showed similar transient immediate postAVR deterioration, followed by progressive improvement in aortic distensibility.10 Overall, these results suggest that alterations in aortic distensibility can be present in patients with BAVs. Because of the facts that improvements in aortic elasticity were observed after AVR or full root replacement in patients with AS, further studies are warranted to evaluate alterations in aortic elasticity after invasive procedures in patients with BAVs. Attila Nemes, Osama I. Soliman, Miklós Csanády, Tamas Forster,

MD, MD, MD, MD,

PhD PhD PhD PhD

Szeged, Hungary and Cairo, Egypt 25 March 2008

1. Schaefer BM, Lewin MB, Stout KK, Byers PH, Otto CM. Usefulness of bicuspid aortic valve phenotype to predict elastic properties of the ascending aorta. Am J Cardiol 2007; 99:686 – 690. 2. Nistri S, Sorbo MD, Basso C, Thiene G. Bicuspid aortic valve: abnormal aortic elastic properties. J Heart Valve Dis 2002;11:369 – 374. 3. Grotenhuis HB, Ottenkamp J, Westenberg JJ, Bax JJ, Kroft LJ, de Roos A. Reduced aortic elasticity and dilatation are associated with aortic regurgitation and left ventricular hypertrophy in nonstenotic bicuspid aortic valve patients. J Am Coll Cardiol 2007;49:1660 – 1665. 4. Nistri S, Grande-Allen J, Noale M, Basso C, Siviero P, Maggi S, Crepaldi G, Thiene G. Aortic elasticity and size in bicuspid aortic valve syndrome. Eur Heart J 2008;29:472– 479.

0002-9149/08/$ – see front matter © 2008 Elsevier Inc. All rights reserved.

5. Yap SC, Nemes A, Meijboom FJ, Galema TW, Geleijnse ML, ten Cate FJ, Simoons ML, Roos-Hesselink JW. Abnormal aortic elastic properties in adults with congenital valvular aortic stenosis. Int J Cardiol. In press. 6. Fedak PW, Verma S, David TE, Leask RL, Weisel RD, Butany J. Clinical and pathophysiological implications of a bicuspid aortic valve. Circulation 2002;106:900 –904. 7. Nemes A, Forster T, Csanady M. Decreased aortic distensibility and coronary flow velocity reserve in patients with significant aortic valve stenosis with normal epicardial coronary arteries. J Heart Valve Dis 2004;13: 567–573. 8. Barbetseas J, Alexopoulos N, Brili S, Aggeli C, Marinakis N, Vlachopoulos C, Vyssoulis G, Stefanadis C. Changes in aortic root function after valve replacement in patients with aortic stenosis. Int J Cardiol 2006;110:74 –79. 9. Nemes A, Galema TW, Geleijnse ML, Soliman OI, Yap SC, Anwar AM, ten Cate FJ. Aortic valve replacement for aortic stenosis is associated with improved aortic distensibility at long-term follow-up. Am Heart J 2007; 153:147–151. 10. Nemes A, Galema TW, Soliman OI, Bogers AJ, ten Cate FJ, Geleijnse ML. Improved aortic distensibility after aortic homograft root replacement at long-term follow-up. Int J Cardiol. In press. doi:10.1016/j.amjcard.2008.04.020

First, Remove the Offending Agent We read with interest the case series by Patel et al1 regarding implantable cardioverter-defibrillators (ICDs) for patients with methadone-induced long-QT syndrome. The study raises several concerns, and we hope this is not construed as future standard of practice. First, in any case of potentially life threatening adverse effects of a medication, 1 of the basic tenets in medical toxicology is to remove the offending agent; opioid withdrawal syndrome is not itself life threatening,2 but in this case series, ICD implantation caused complications, including infection and perforation, at an alarming rate even for a small sample size (25%).1 How was the decision made to forgo the former in lieu of the latter? Given these issues, we are interested in learning how the data necessary for informed consent were presented to the patients. Furthermore, it was unclear from the inclusion criteria that symptomatic Torsades de Pointes was present in all the patients before placement of the ICDs.1 The costs of ICD implantation, www.AJConline.org