Institute of Cardiology Warsaw, Poland

Transcription

1 Mateusz Śpiewak, Elżbieta K. Biernacka, Łukasz A. Małek, Jolanta Miśko, Joanna Petryka, Mirosław Kowalski, Barbara Miłosz, Magdalena Żabicka, Piotr Hoffman, Witold Rużyłło Institute of Cardiology Warsaw, Poland

2 None of the authors has reported any conflict of interest 2

3 Pulmonary regurgitation (PR) is often observed in patients after repair of tetralogy of Fallot (TOF) PR is recognized as the most common problem in this population Chronic PR leads to severe RV dilatation, which may become irreversible despite pulmonary valve replacement Long-standing volume overload of PR has a negative impact on RV systolic function 3

4 Apart from PR, right ventricular outflow tract obstruction (RVOTO) may also be present in patients with repaired TOF It can be a result of residual obstruction after primary repair and/or degenerative changes in the RV-to-pulmonary artery conduit Some patients develop combined lesions consisting of significant PR and significant RVOTO (PR+RVOTO) 4

5 In experimental studies, it has been demonstrated that combined PR+RVOTO may act as a potential protective factor limiting the negative impact of PR on RV size and myocardial contractility 5

6 We hypothesized that in patients with similar levels of PR, RV volumes and function are better preserved in the presence of RVOTO To evaluate these issues we have decided to perform the current study 6

7 The study population comprised consecutive patients with significant PR after TOF repair who had undergone CMR study Exclusion criteria were: more than mild regurgitation at a valve other than the pulmonary valve, intracardiac and/or extracardiac shunt, poor quality of CMR images, incomplete CMR data set or incomplete echocardiographic study 7

8 The maximal velocity across the right ventricular outflow tract (RVOT) was determined using continuous wave Doppler Significant RVOTO (at least moderate) was defined as peak gradient across RVOT 30 mmhg 8

9 All CMR studies were performed with a 1.5T scanner The CMR protocol included SSFP breathhold sequences in 2-, 3- and 4-chamber views and a stack of short axis images Pulmonary artery flow measurements were performed with the use of a phase contrast gradient echo sequence during free breathing Significant PR was defined as PRF >20% 9

10 10

11 In 41 patients (98%), echo was performed within 2 months from CMR study In 30 of them (71% of the entire group), the interval between CMR and echo studies was 1 day, including 23 cases (55%) with both studies performed on the same day. The maximal interval between the studies was 72 days 11

12 All patients n=42 Isolated PR n=33 Combined PR+RVOTO n=9 Age at CMR study, years (IQR) 24.9 ( ) 24.3 ( ) 26.6 ( ) Age at TOF repair, years (IQR) 4.3 ( ) 4.3 ( ) 4.6 ( ) Time from TOF repair, years 20.7 ± ± ± 3.8 Type of TOF repair Patch, n (%) 30 (71.4) 23 (69.7) 7 (77.8) Conduit, n (%) 4 (9.5) 2 (6.0) 2 (22.2) Details unknown, n (%) 8 (19.1) 8 (24.3) 0 Palliative procedure in the history, n (%) 12 (28.6%) 10 (30.3) 2 (22.2) Age at first palliation, years 2.5 ± ± and 6.4* Time from first palliation to TOF repair, years 6.6 ± ± and 22.8* Males, n (%) 25 (59.5%) 22 (66.7) 3 (33.3) NYHA group, % of patients I = 73.8 II= 26.2 * There were only two patients in this subgroup. Data are presented for each patient. I = 75.8 II= 24.2 I = 66.7 II=

13 Isolated PR Combined P PR+RVOTO RVEDV (ml/m 2 ) ± ± RVESV (ml/m 2 ) 92.7 ± ± RVSV (ml/m 2 ) 73.4 ± ± RVEF (%) 45.0 ± ± PRF (%) 36.9 ± ± PRV (ml/m 2 ) 27.7 ± ± peak RVOT gradient (mmhg) 12.3 ± ± 15.6 < RVM (g/m 2 ) 33.5 ± ± RVM/RVEDV (g/ml) 0.20 ± ±

14 Isolated PR Combined P PR+RVOTO LVEDV (ml/m 2 ) 83.7 ± ± LVESV (ml/m 2 ) 37.0 ± ± LVSV (ml/m 2 ) 46.7 ± ± LVEF (%) 56.5 ± ± LVM (g/m 2 ) 58.6 ± ±

15 Models including PRF as independent variable Dependent variable Predictors β P RVEDV (ml/m 2 ) PRF (%) Peak RVOT gradient (mmhg) Sex (for male sex) RVESV (ml/m 2 ) Peak RVOT gradient (mmhg) Models including PRV as independent variable Dependent variable Predictors β P RVEDV (ml/m 2 ) PRV (ml/m 2 ) Peak RVOT gradient (mmhg) Sex (for male sex) RVESV (ml/m 2 ) PRV (ml/m 2 ) Peak RVOT gradient (mmhg)

16 Combined PR+RVOTO, when compared to isolated PR, leads to improved RVEF and smaller RV dilatation The confounding effect of RVOTO on RV size and function needs to be taken into consideration in CMR studies evaluating patients after TOF repair 16

17 Many studies evaluating the impact of PR on RV size and function with the use of CMR have omitted a possible confounding effect of RVOTO on the parameters analysed Since combined PR+RVOTO influences RV dimensions and RVEF, and the consequences of combined lesions differ from those in isolated PR, RVOTO should be considered an important confounding factor when the impact of PR on RV is assessed 17

18 A possible mechanism responsible for lower RV volumes and improved RV systolic function in patients with combined PR+RVOTO remains unknown It can be speculated that, by promoting hypertrophic remodelling, RVOTO acts as a protective mechanism against RV dilatation 18

19 Considering a relatively small number of patients with combined PR+RVOTO, the results need to be interpreted with caution and confirmed in larger studies Although smaller RV volumes and higher RVEF can be regarded as proxies for better RV performance, these results as stand-alone data may not be sufficient to comprehensively describe the functional benefit of having a combined RVOT lesion Right ventricular systolic pressure is more accurate to estimate the severity of RVOTO 19

20 Mateusz Śpiewak, Elżbieta K. Biernacka, Łukasz A. Małek, Jolanta Miśko, Joanna Petryka, Mirosław Kowalski, Barbara Miłosz, Magdalena Żabicka, Piotr Hoffman, Witold Rużyłło Institute of Cardiology Warsaw, Poland