Discrepancies between Doppler and catheter gradients in ventricular septal defect: A correction of localized gradients from pressure recovery phenomenon

Although very high gradient levels were measured during the evaluation of ventricular septal defect (VSD) in daily practice, these measurements are generally interpreted as erroneous and thus neglected. Our aim was to assess the features of VSD's having erroneous interventricular pressure gradients by echocardiography. A 46 patients were enrolled in the study. The patients with higher Doppler-derived interventricular gradient than brachial systolic blood pressure were compared with patients with lower gradient (group 1, n = 26; group 2, n = 20, respectively) in terms of echocardiographic characteristics of VSD. No significant relations were observed in systolic and diastolic blood pressure and interventricular synchronicity between two groups (117.1 ± 6.7 vs 110.2 ± 6.3 mmHg, p = 0.145; 74.7 ± 4.3 vs 73.2 ± 4.9 mmHg, p = 0.32; 31.2 ± 5.5 vs 33.2 ± 4.9 msn, p = 0.29, respectively). Left ventricular end-diastolic and end-systolic diameters were greater in group 2 (46.6 ± 3.5 vs 49.5 ± 4.5, p = 0.022; 30.3 ± 2.5 vs 32.9 ± 3.2, p = 0.004, respectively). Doppler-derived interventricular pressure gradients were significantly higher in group 1 (144.4 ± 13.6 vs 75.7 ± 5.1 mmHg, p < 0.001, respectively). Defect width was significantly lower (3.20 ± 0.40 vs 4.8 ± 1.8 mm, respectively, p < 0.05), and length was greater in group 1 patients (5.75 ± 0.90 vs 2.80 ± 0.80 mm, p < 0.05, respectively). There was a significant positive correlation between pressure gradient and defect length (r = 0.84, p < 0.001), and a negative correlation between pressure gradient and defect width (r = -0.66, p < 0.001). Defect length/width was significantly greater in group 1. With the cut-off value of 1.2, defect length/width was able to predict tunnel-type VSD with sensitivity of 88.5% and specificity of 72.7%. Continuous-wave Doppler method may overestimate interventricular pressure gradients in patients with tunnel-type ventricular septal defect.