However, supportive data for these strategies are limited or nonexistent. Systemic an- ticoagulation has the potential for adverse as well as possible helpful effects. Mechanical circulatory and pulmonary support, lung transplantation with concomitant repair of anatomic cardiovascular defects, and heart lung transplantation have all been applied in patients with ACHD with Eisen- menger syndrome with deteriorating functional ability. Indications for such therapies for adults with Eisen- menger syndrome are not standardized; comparative outcomes have not been tested, and to date successes have been limited. However, pharmacological treat- ment of PAH is helpful in the management of certain patients with Eisenmenger syndrome. See Section 3.3 for recommendations on who should perform surgeries, cardiac catheterization, and other procedures in these patients; Section 3.4 for rec- ommendations on diagnostic evaluation; and Table 33 for routine testing and follow-up intervals. Recommendation-Specific Supportive Text 1. Right-to-left shunting through septal defects or connections between the great arteries associ- ated with subpulmonary ventricular hypertension may be diagnosed as Eisenmenger syndrome. PAH medications may be beneficial for patients with Eisenmenger syndrome; however, other conditions may cause right-to-left shunting for reasons other than shunt-related PAH and thus may require different treatment options. These other conditions include: a) severe pulmonary hy- pertension of other cause (eg, thromboembolic disease, rheumatic disease), b) subpulmonary chamber outflow obstruction, c) abnormalities of subpulmonary chamber compliance, and d) vas- cular streaming. Accurate diagnosis is necessary to guide therapy. For example, PAH therapies will not be beneficial if the source of right-to- left shunting is RVOT obstruction; rather, allevi- ation of the RVOT obstruction is the necessary treatment. Accurate diagnosis of Eisenmenger syndrome and exclusion of other potential con- tributors to right-to-left shunting or pulmonary hypertension by means of advanced imaging and cardiac catheterization are crucial prerequisites to optimize therapy for adults with Eisenmenger syndrome. 2. 