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Table 1 Descriptive statistics of the case study sample stratified by LVAD groups. Continuous variables are represented with I quartile/median/III quartile and categorical variables with percentage (relative frequencies). The Standardized Mean Differences (SMDs) on the unbalanced case study sample are reported in the last column of the table

From: Oversampling and replacement strategies in propensity score matching: a critical review focused on small sample size in clinical settings

  Combined (N=103) N HeartWare HVAD (N=46) Jarvik2000 LVAD (N=57) SMD
Sex (Female) 15 % (15) 103 17 % ( 8) 12 % ( 7) -0.14
Intermacs I 42 % (43) 103 39 % (18) 44 % (25) 0.10
Intermacs II 27 % (28) 103 39 % (18) 18 % (10) -0.49
Intermacs III 15 % (15) 103 13 % ( 6) 16 % ( 9) 0.08
Intermacs IV 17 % (17) 103 9 % ( 4) 23 % (13) 0.39
Age (years) 50/60/66 103 42/53/62 58/63/67 0.89
BSA 1.8/1.9/2.0 103 1.7/1.8/2.0 1.8/1.9/2.0 0.48
Cardiomyopathy : DCM 38 % (39) 103 52 % (24) 26 % (15) -0.55
IHD 55 % (57)   43 % (20) 65 % (37) 0.44
Other 7 % ( 7)   4 % ( 2) 9 % ( 5) 0.18
Severe Right Coronaropathy 27 % (28) 103 24 % (11) 30 % (17) 0.13
CI (L/min/m2) 1.5/1.7/2.0 103 1.5/1.6/2.0 1.4/1.7/1.9 -0.14
Preoperative VO2 at peak (ml/min/m2) 9.2/11.0/11.9 78 9.8/11.4/12.4 9.1/10.9/11.7 -0.26
Smoker 46 % (45) 98 41 % (19) 50 % (26) 0.18
Dislipidemia 42 % (43) 103 30 % (14) 51 % (29) 0.43
Hypertension 48 % (49) 103 41 % (19) 53 % (30) 0.23
Preoperative AF 42 % (43) 103 39 % (18) 44 % (25) 0.10
Cancer 10 % (10) 103 4 % ( 2) 14 % ( 8) 0.34
Diabetes 24 % (25) 103 17 % ( 8) 30 % (17) 0.30
Peripheral Vascular disease 24 % (25) 103 22 % (10) 26 % (15) 0.11
COPD 5 % ( 5) 103 4 % ( 2) 5 % ( 3) 0.04
ICD 62 % (64) 103 48 % (22) 74 % (42) 0.55
Reoperation 16 % (16) 103 7 % ( 3) 23 % (13) 0.47
Preoperative platelets (103/mm3) 156/214/285 103 170/237/310 152/205/265 -0.40
BNP 3592/ 6362/12,460 89 2970/ 6173/13,247 3800/ 6961/11,751 -0.06
GFR (mL/min/m3) 50/68/90 96 58/72/90 44/58/90 -0.26
Creatinine (mg/dL) 0.94/1.26/1.58 99 0.93/1.23/1.47 0.96/1.32/1.64 0.30
ASA classification : 3 29 % (30) 103 30 % (14) 28 % (16) -0.05
4 70 % (72)   67 % (31) 72 % (41) 0.10
5 1 % ( 1)   2 % ( 1) 0 % ( 0) -0.21
PAPS 37/44/55 94 38/43/55 35/46/56 0.02
EF 16/19/22 103 16/20/23 17/19/21 -0.07
VTD (mL/m2) 109/130/154 100 100/130/156 114/130/154 -0.01
TAPSE 12/14/18 103 12/14/16 13/15/19 0.37
AF right ventricular 25/31/38 103 21/29/38 28/33/38 0.37
IT : 0 2 % ( 2) 103 0 % ( 0) 4 % ( 2) 0.27
1 49 % (50)   48 % (22) 49 % (28) 0.03
2 35 % (36)   35 % (16) 35 % (20) 0.01
3 9 % ( 9)   11 % ( 5) 7 % ( 4) -0.14
4 6 % ( 6)   7 % ( 3) 5 % ( 3) -0.05
IM : 0 14 % (14) 103 11 % ( 5) 16 % ( 9) 0.15
1 25 % (26)   15 % ( 7) 33 % (19) 0.43
2 48 % (49)   59 % (27) 39 % (22) -0.41
3 10 % (10)   11 % ( 5) 9 % ( 5) -0.07
4 4 % ( 4)   4 % ( 2) 4 % ( 2) -0.04
IAO : 0 69 % (71) 103 74 % (34) 65 % (37) -0.20
1 30 % (31)   24 % (11) 35 % (20) 0.25
3 1 % ( 1)   2 % ( 1) 0 % ( 0) -0.21
Preoperative CVVH 13 % (13) 103 7 % ( 3) 18 % (10) 0.34
More than 1 days with preoperative CVVH 13 % (13) 103 7 % ( 3) 18 % (10) 0.34