Drug treatment for protection of the aorta previously consisted exclusively of β-blocker administration. The effectiveness of this has been confirmed in a prospective and randomized study which demonstrated a slowing in the rate of aortic root dilation in pediatric patients (Shores et al. 1994). However, animal experiments have shown that angiotensin II receptor blockers such as losartan and matrix metalloproteinase inhibitors also have stabilizing effects on the metabolism of the aortic wall (Habashi et al. 2006). A large study in the United States is therefore currently testing whether the protective effect of losartan on the aorta is superior to the effects of β-blockers in patients with Marfan syndrome.
Pregnancy
There is thought to be a high risk of aortic complications during pregnancy in Marfan patients. According to the current guidelines, the risk of aortic rupture or aortic dissection during pregnancy must be regarded as high if the diameter of the aortic root is ≥ 40 mm or an aortic dissection has already occurred beforehand (Hiratzka et al. 2010). Several authors have reported an increased risk only from 45 mm upwards (Meijbook et al. 2005). Women at increased risk who wish to have children should be advised against pregnancy, or prophylactic aortic root replacement should be discussed with them.
Surgical treatment
The improved life expectancy in patients with Marfan syndrome is mainly achieved by prophylactic replacement of the aortic root, which prevents spontaneous rupture or dissection of the aortic root. The standard operation on a typical aorta with Marfan changes until recently consisted of complete replacement of the aortic root with a valve-bearing conduit (Gott et al. 1999a). The Bentall technique or several of its variants were used in this procedure (von Kodolitsch et al. 1998).
There are two important trends in aortic root surgery for Marfan patients. Firstly, the criteria for prophylactic replacement of the aortic root have become increasingly generous during the last 25 years and the current criterion is a diameter ≥ 45 mm. Continuing improvements in the results, with very low mortality rates in elective operations, have played a role in this, along with a recognition that even slightly dilated aortae with a diameter of 40–45 mm involve a risk of acute complications, while the postoperative course in patients who have survived an aortic dissection is in principle associated with higher complication rates and a poorer quality of life (von Kodolitsch et al. 2008; Gott et al. 1999b).
Secondly, the view is currently becoming accepted that the conduit operation with complete replacement of the aortic root must not be regarded as the standard operation; instead, the primary aim should be to achieve a valve-preserving reconstruction of the aortic root. This changed approach has also been reflected in the current guidelines (Hiratzka et al. 2010). Valve-preserving surgical techniques are derived from Yacoub, along with a modified technique by David. They both developed techniques for reconstructing the aortic root by preserving the physiological valvular apparatus while still keeping a radical resection of the entire proximal aorta. Yacoub’s remodeling techniques have not become established, due to unfavorable long-term results with higher rates of aortic valve insufficiency and therefore reimplantation techniques must currently be regarded as the standard (Fig. 2.1-25). Reconstruction of the aortic root can be carried out with good early and medium-term results, avoiding the disadvantages of valvular replacement with the associated increased risk of thromboembolism and endocarditis (Bernhardt et al. 2011a). The aim in mitral valve surgery is currently to use a valve-preserving approach, and although present experience with mitral valve reconstruction in Marfan patients is not based on a large number of cases, it is highly promising (Gillinov et al. 1994; Bernhardt et al. 2011b).
Fig. 2.1–25 In the current variants of the David operation, the aortic tissue is completely excised along the crown-shaped upper annulus of the aortic sinus. The tissue from the aortic sinus, with the valve-bearing tissue, is preserved. However, this approach removes the aortic tissue from the coronary orifices, and reimplantation of the coronaries into the tubular prosthesis that replaces the aorta is therefore an integral component of all David operations. The illustration shows different variants of the David operation, dividing into David I–V types, proposed by Miller (2003). The upper row in the illustration shows the variants of the operation that are described as David reimplantation techniques. The basic principle in these techniques involves suturing the natural valve-bearing sinus into the aortic prosthesis and attaching the aortic prosthesis both to the base of the sinus and along the upper crown-shaped annulus. The David I operation consists of this basic technique. In the David IV and V operations, the ascending aorta is replaced with an additional, narrower tubular prosthesis and the aortic sinus is formed by a wider tubular prosthesis into what is known as a neo-sinus. The lower row in the illustration shows the variants of the operation that are known as David remodeling techniques. The basic variant in this technique is the David II operation, in which as in the Yacoub procedure the upper, crown-shaped annulus of the aortic sinus is directly sutured to a correspondingly trimmed tubular prosthesis. David uses this surgical method only in patients with no dilation of the lower annulus. In the David III variant, the lower annulus is also stabilized externally with a felt strip that is sutured in.
Treatment for other genetically determined aortic diseases
The principles of medical management of genetically determined aortic diseases, excluding Marfan syndrome, are based on the management of Marfan syndrome. However, there are signs that the practical approach used may be starting to diverge from that used in management of Marfan syndrome, depending on the underlying syndrome and the gene mutation causing the condition. These differences mainly affect the indication for surgical intervention, which sometimes used to be very substantial. It will also be conceivable in the future for specific aortic diseases to be treated with drugs in different ways, depending on the pathological mechanism involved (von Kodolitsch et al. 2010; Milewicz et al. 2008). Table 2.1-7 sums up the surgical treatment recommendations that are taylored to a relevant gene defect or the presence of a specific aortic syndrome (Table 2.1-6).
Endovascular therapy in genetically determined aortic diseases
Endovascular treatment has become established for nongenetic diseases of the descending aorta and infrarenal aorta, due to the lower rates of perioperative morbidity and mortality in comparison with open surgery (Svensson et al. 2008). However, this basically requires the presence of an undilated, healthy vascular segment in which the radial force of the stent graft can achieve a seal. This prerequisite for safe anchoring of the stent graft is certainly present in Marfan syndrome and other