Reliability of Conventional Conventional echocardiography - PDF document

3/12/2019 Reliability of Conventional Conventional echocardiography Echocardiography Assessment of • Subjective assessment e.g. RV size, septal flattening Pulmonary Hypertension in • Measurements utilizing 2D images or Doppler (measurement of preterm infants velocity by echo) e.g RV area, TR jet Hythem Nawaytou, MBBCh, MSc Reliability: Assistant Professor of Pediatric Cardiology • the quality of being trustworthy or of performing consistently well UCSF • the degree to which the result of a measurement, calculation, or specification can be depended on to be accurate Points of discussion Screening for pulmonary vascular disease • Does my patient have pulmonary vascular disease? Are they a high risk patient? • How bad is their pulmonary vascular disease? • How is the pulmonary vascular disease affecting the heart function? • Did you look at the pulmonary veins? 1

3/12/2019 How is pulmonary vascular disease defined? Flow is not a constant Pressure = Flow x Resistance Pulmonary Hypertension Pulmonary Vascular Resistance High pressure and low resistance e.g PDA and VSD Are they the same? Low pressure and high resistance e.g. RV failure Which one is better? Changes in resistance are not associated with proportional changes in pressure Pressure definition versus resistance definition • PVR is a better determinant of mortality 35% of the cohort would be classified differently between the two definitions PVR 3.2 ‐6WU • No added value to using a pressure criteria Steurer et al, Pediatr. Pulmonol., in press Steurer et al, Pediatr. Pulmonol., in press 2

3/12/2019 Accuracy of echo PAP estimation using PA pressure Different definitions of PVD gives different to define PVD results of echo reliability TR Jet POSITIVE ECHO Septal Flattening TR jet velocity >2.9m/sec OR VSD or PDA systolic flow velocity estimating peak systolic PAP > 35mmHg OR Systolic septal flattening was present 70 70 65 M ean pulmonary artery pressure Mean pulmonary artery pressure 65 Subjectively 60 60 55 55 RA enlargement 50 50 RV dilation 45 45 (mmHg) 40 (mmHg) RV hypertrophy 40 35 35 PA dilation 30 30 25 25 Septal flattening 20 20 15 15 10 10 n=29 WHO n=29 PVR only 5 5 Agreement = 72% Agreement = 62% Definition Definition 0 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Indexed pulmonary vascular resistance (WU x m 2 ) Indexed pulmonary vascular resistance (WU x m 2 ) B A True negative False positive True positive False negative True negative False positive True positive False negative Mourani, Pediatrics 2008;121:317-325 Accuracy of echo PAP estimation using PVR to define PVD What to do for patients with a shunt? PVD DEFINED AS POSITIVE ECHO PVRi >3WU TR jet velocity >2.9m/sec OR VSD or PDA systolic flow velocity estimating peak systolic PAP > 35mmHg OR Shunt Direction of flow (N) P value Systolic septal flattening was present PVRi median (Q1,Q2) L to R Bidirectional R to L 0.18 (n=8) (n=2) (n=1) Accuracy Sensitivity Specificity AUC Confidence PDA interval 4.3 (2.5,5.5) 1.7 /3 8.9 Positive echocardiogram for PH L to R Bidirectional R to L 0.2 72 90.5 25 0.58 0.39‐0.76 (n=3) (n=1) (n=1) VSD Septal flattening 69 85.7 25 0.61 0.42‐0.79 2.8‐4.6 12.6 8.9 Positive echocardiogram for PH excluding 89 93.3 66.7 0.8 0.52‐0.94 patients with PDA (n=18) Septal flattening excluding patients with 83 86.7 66.7 0.8 0.52‐0.94 PDA (n=18) Positive echocardiogram for PH excluding A left to right shunt does not indicate absence of PVD 93 91.7 100 0.96 0.66‐0.99 patients with PDA & VSD (n=14) Septal flattening excluding patients with 93 91.7 100 0.96 0.66‐0.99 PDA & VSD (n=14) 3

3/12/2019 Conclusion for screening PVD Severity of pulmonary vascular disease • Echo is a good screening test for PH and elevated PVR, but be prepared for some negative catheterization results • A positive echo is reliable for elevated PVR in patients without PDA and VSD. • Echo will never rule out PVD in preterm infants because we don’t catheterize patients with negative echoes, hence we don’t know the accuracy of a negative study. Reliability of Doppler estimation of severity of pulmonary hypertension Ability of echocardiography (ECHO)-estimated sPAP to predict the severity of PH determined Limits of agreement are wide (up to 40‐ 50 mmHg) with cardiac catheterization (CATH). Wider limits at higher pressures TR Jet = 40mmHg 11% UNDERDIAGNOSIS A 11% OVERDIAGNOSIS PI Jet = 50mmHg PDA = 30mmHg B Groh , J Am Soc Echocardiogr (2014) 27(2) 163–71 Ge, Int J Cardiol (1993) 40(1):35–43) Ge, Am Heart J (1992) 124(1):176–82) Ge, Clin. Cardiol. 15, 818‐824 (1992) Mourani. Pediatrics 2008;121:317-325 4