The correlation of AVA measured by transthoracic, transesophageal echocardiography and cardiac CT

Transcription

1 The correlation of AVA measured by transthoracic, transesophageal echocardiography and cardiac CT R.Petr, H.Linkova, J.Knot, E.Paskova, J.Daniel, M.Labos Cardiocenter of University Hospital Kralovske Vinohrady and 3 rd Faculty of Medicine of Charles University Prague, Czech Republic.

2 I have nothing to disclose.

3 Introduction Aortic valve stenosis is the most common valvular disease. Iung B, Euro Heart Survey, European Heart J, 2003

4 Surgical aortic valve replacement Surgical aortic valve replacement is the gold standard for symptomatic patients with severe aortic valve stenosis (AS) Gasch WH, Schick EH, 2000

5 TAVI Percutanneous aortic valve implantation (TAVI) is a feasible alternative treatment for patients with severe AS who are considered at high risk or have contraindications for conventional surgery Smith CR, NEJM, 2011

6 Aortic valve area Aortic valve area (AVA) is accepted marker of severity of aortic stenosis Pressure gradient leads to an underestimation of the severity of low-flow and/or low-gradient severe AS

7 CT for evaluation of patients before TAVI Cardiac computed tomography (CT) is the standard imaging modalitity for the evaluation of patients before TAVI

8 CT for evaluation of patients before TAVI Aortic valve (morphology/annulus sizing), aortic root, coronary ostia Access (femoral/ subcalvian/ apical) Using the same datasets, planimetric measurement of AVA is possible

9 The aim To compare the assessment of AVA using cardiac CT with the measurement of AVA by transthoracic (TTE) and transesophageal (TEE) planimetry and with AVA calculated by the continuity equation in patients with severe aortic stenosis

10 Methods Single center study A total number of 35 patients with severe aortic stenosis underwent TTE, TEE and cardiac CT as a pre-evaluation before TAVI between 1/jan/2011 and 31/dec/2011 AVA was measured using transverse projections by TTE, TEE and CT The calculation of AVA using the continuity equation was done in all patients

11 Statistical analysis Continuous data were expressed as mean + SD Agreement for the assesment of AVA between the modalities were determined by Pearson s correlation coefficient for linear regression and Bland-Altman analysis The 95 % limit of agreement was defined as the values + 2SD from the mean value of differences P value < 0.05 was considered statistically significant Good inter-observer agreement was defined as an intraclass correlation coefficient (ICC) >0.8

12 Echocardiography The examinations were performed using a commercially available system (Vivid 7, GE medical systems, Milwaukee, WI, USA ). Images were recorded from standard parasternal and apical views. The morphology and function of heart valves was assessed using the region of interest technique. All the measurements were stored online using computer raw data format, were recorded. Three beats in sinus rhythm or five to ten beats, in case of atrial fibrillation, were averaged for measurement of all quantitative parameters. 15 random cases were selected for inter-observer analysis, that showed good agreement (ICC 0.95).

13 The continuity equation Measurements of the peak flow velocities of the left ventricular outflow tract (V1) and across the aortic valve (V2) orifice using pulsed-wave and continuouswave Doppler. The LVOT diameter (LVOTD) AVA is estimated by continuity equation: AVA=(LVOT area x LVOT TVI ) / AV TVI LVOT diameter

14 Planimetry TTE, TEE

15 CT 256-slice scanner (Brillance ict, Philips Healhcare, Cleveland, OH, USA) ECG gated retrospective helical aquisition kV tube voltage / effective mas tube current 10 series in 10% steps through the R-R interval were reconstructed Data were transfferred to Review software (Comprenhensive Cardiac Analyses, Brillance Workspace v 4.0, Philips Healthcare, Cleveland, OH, USA) Endsystolic phase for measurement of AVA was identified Oblique transverse cross-section across the aortic valve at the level of the minimal AVA was used for measurement 15 random cases were selected for inter-observer analysis, that showed good agreement (ICC 0.96)

16 CT

17 Measurements

18 Results Baseline characteristics N=35 Age (years) Male (%) 20 (57%) Height (cm) Weight (kg) BMI (kg/m 2 ) Comorbidities Hypertension 15 (43%) Hyperlipidemia 16 (46%) Diabetes mellitus 7 (20%) Smoking 11 (35%) History of MI 8 (23%) Echocardiography AVA (cm 2 ) PG max (mmhg) PG mean (mmhg) EF (%)

19 Results Method AVA CT (cm 2 ) The continuity equation (cm 2 ) TEE (cm 2 ) TTE (cm 2 )

20 Comparision of CT planimetry and calculation by the continuity equation in the assessment of AVA r 2 =0.61, p<0.01 Mean value of difference (+ SD) p<0.05

21 Comparision of CT and TEE in the assessment of AVA r 2 =0.94, p<0.01 Mean value of difference (+ SD) p<0.05

22 Comparision of CT and TTE in the assessment of AVA r 2 =0.75, p<0.01 Mean value of difference (+ SD) p<0.05

23 Conclusion The assessment of AVA using cardiac CT is in excellent agreement with the calculation of AVA from the continuity equation and with planimetric measurements by TTE and TEE.

24 Limitations Small sample size Invasive measurements of AVA were not performed Patient population is limited only to high risk patients considered for TAVI

25 Thank you for your attention