Pulmonary hypertension in patients with ostium secundum atrial septal defect--is it related to echocardiographic complexity?

Introduction: Atrial septal defect (ASD) is one of the most common congenital heart defects. Patients may reach adulthood before being diagnosed and sometimes develop pulmonary hypertension (PH). According to the latest Euro Heart Survey on Congenital Heart Disease, 24.77% of ASD patients develop PH. The reasons for this evolution in only some patients are still unknown. Objectives: To assess the prevalence of PH in patients with ostium secundum ASD (osASD) in our district and to determine whether the echocardiographic morphology of the defect can be an indicator of evolution to PH. Methods: The study included 181 consecutive patients, mean age 43.1±18.4 years, 65.2% women, with a diagnosis of osASD, referred for transthoracic and transesophageal evaluation in our center from January 2000 to September 2008. We assessed right atrial (RA) and ventricular (RV) dimensions, measured the rims and size of the ASD and deter- mined pulmonary artery systolic pressure (PASP) (RV/RA gradient plus a value corre- sponding to the degree of inferior vena cava collapse). The type of shunt at the atrial level was assessed with intravenous injection of agitated saline. Statistical analysis was performed using SPSS 15.0. Results: Seventy-seven patients (42.5%) had moderate to severe enlargement of the right heart chambers and 48 (26.5%) had pulmonary hypertension, defined as PASP of over 40 mmHg (equivalent to mean pulmonary artery pressure of 25-30 mmHg). Patients with PH were older (52.8±16.9 vs. 39.0±17.6 years; p<0.001) and had larger defects (19.7±9.6 mm vs. 13.1±7.1 mm; p<0.001). The proportion of women was similar in both groups (64.6% in patients with PH vs. 68.75% in those without; p=NS). Most patients with PH had ASDs with more complex shapes on echocardiography. However, some patients with simpler and smaller defects, such as central ASD with a diameter of <5 mm, also developed PH. The prevalence of PH in patients with closed ASDs was much lower: 20.3% vs. 43.75%; p<0.002. Conclusions: According to these data, development of PH in patients with ASD is frequent and seems to be related to the diameter of the defect. However, patients with smaller and simpler defects may also develop PH. This seems to occur at older ages and not to be gender-dependent. Early ASD closure appears to prevent this.