Avoidance of birth control entirely is not a safe, acceptable option. Patients can travel safely on commercial airlines without undue risk.S3.16-23 Preflight simulation testing or mandated supplemental oxygen are not usually indicated, although adequate hydration and movement during the flight are appropriate. Measurement of coagulation parameters (eg, activated partial thromboplastin time, international normalized ratio, thrombin time) in a patient with an elevated hematocrit >55% requires adjustment of anticoagulant volume in the blood collection vials to account for reduced plasma volume in the draw.S3.16-24 ACHD indicates adult congenital heart disease and CHD, congenital heart disease. CLINICAL STATEMENTS AND GUIDELINES have a beneficial effect on long-term outcomes in pa- tients with Eisenmenger syndrome.S3.17-10 Similarly, there are limited data on the use of pulmonary vasodilator therapy in Fontan patients, in whom the pulmonary vas- cular resistance may be abnormal.S3.17-11 S3.17-13 Because of the lack of data, clinical recommendations regarding pharmacological therapy for patients with ACHD are unsupported. Individualized care is needed, recognizing the potential benefits and risks of the therapy relative to patient-specific anatomic and physiological issues. See Online Data Supplement 22 for referenced studies. 4. SPECIFIC LESIONS 4.1. Shunt Lesions 4.1.1. Atrial Septal Defect Recommendations for Atrial Septal Defect Referenced studies that support recommendations are summarized in Online Data Supplement 26 and the systematic review COR LOE Recommendations Diagnostic I C-EO Pulse oximetry at rest and during exercise is recommended for evaluation of adults with unrepaired or repaired ASD with residual shunt to determine the direction and magnitude of the shunt. 