Catheterization via the radial artery has become the method of choice for evaluation of the coronary arteries; however in patients requiring simultaneous coronary and right heart catheterization upper extremity access is not commonly used. In the present study we aimed to assess whether simultaneous left and right heart catheterization via the radial artery and antecubital vein might increase the vascular access site complications. In this prospective cohort study, 49 patients with congenital and valvular heart disease requiring both left and right heart catheterization were enrolled, and rates of vascular access complications, including radial artery obstruction (RAO), were compared to 49 subjects in the control group who underwent catheterization only via radial artery access. No major vascular complications occurred in the study population. Post-procedural radial artery obstruction was detected in 14 patients (28.5%) in the venous-radial artery group and 7 (14.2%) in the control group (P = 0.09). Age, sex, body mass index, wrist circumference, hemoglobin concentrations, and history of smoking, diabetes mellitus, hypertension, and anticoagulant use did not affect the rate of radial pulse perseverance. However, shorter times of radial compression device removal were significantly related to lower rates of radial artery obstruction in both groups. Right and left heart catheterization via an upper-extremity route in patients with congenital and valvular heart disease is safe and practical with greater patient comfort and no serious vascular complications. A longer duration of radial compression is an important predictor of RAO, regardless of using additional upper-extremity venous access.