ESC Congress 2010 edition:2010 location:Stockholm, Sweden date:28 August - 01 September
Introduction: Volume overload of the pulmonary circulation in patients with atrial septal defect (ASD) type secundum causes pulmonary vascular disease over a long period of time. However, non-invasive assessment of mild pulmonary vascular disease remains difficult. As PVR normally decreases with exercise, we hypothesized that PVR would fall in those in whom normal circulation is restored early (<40 years of age), but may be altered in those with later closure (>40 years of age) and/or those in whom an ASD remained unclosed.
Methods: Forty-five patients with ASD type secundum (18 with open and 27 with closed ASD) and 20 controls were consecutively enrolled in the study. All underwent standard and symptom-limited bicycle stress echocardiography. PVR was calculated as the ratio of pulmonary artery pressure to cardiac output (total PVR) or using linear regression analysis. (dynamic PVR). The appropriate statistical analysis was performed.
Results: In contrast with controls (5.2±1.8 to 3.8±1.2 mmHg/L/min; P<0.0001 for younger and 5.2±0.8 to 3.8±0.5 mmHg/L/min; P=0.003 for older controls) and patients with an ASD closed at an earlier age (5.5±1.7 to 3.9±1.1 mmHg/L/min; P=0.001), total PVR did not change from rest to peak exercise in younger patients with an open ASD (3.6±1.2 to 4.1±1.1 mmHg/L/min; P=0.298), in older patients with an open ASD (4.3±1.6 to 4.7±1.0 mmHg/L/min; P=0.052) and in patients with an ASD closed at a later age (5.9±2.4 to 5.7±0.8 mmHg/L/min; P=0.458).
Conclusion: Younger and older patients with an open ASD and patients with an ASD closed at a later age were unable to lower total PVR from rest to peak exercise. Whereas this may be due to a limited pulmonary vascular reserve in younger patients, it may attributed to the development of pulmonary vascular lesions in the older group. Whether lowering PVR in older patients improves functional capacity requires further evaluation.