Utility and correlation of known anticoagulation parameters in the management of pediatric ventricular assist devices

Table 1 Patient demographics

	Patient 1 K	Patient 2 S	Patient 3 P	Patient 4 N
Diagnosis	DCM	DCM	CHB, DCM	DCM
Age	13 mo	5 mo	8 mo	10 yr
Weight	8.4 kg	7.2 kg	8.1 kg	24.5 kg
Gender	F	M	M	F
Type of VAD	LVAD	LVAD	LVAD	LVAD
Days on VAD	141	69	13	54
Outcome	OHT	OHT	OHT	OHT

Relevant clinical data from the four patients studied including diagnosis prior to receiving VAD, type of ventricular support (LVAD), absolute number of days on VAD support and eventual patient outcome. All patients received Berlin EXCOR devices as bridge to successful transplantation. DCM: Dilated cardiomyopathy; CHB: Congenital heart block; OHT: Orthotopic heart transplantation; LVAD: Left ventricular assist device.

Table 2 Distribution of values for various measures of coagulation status

Test	n	Minimum	Maximum	mean	SD
Prothrombin time	97	12.5	30.8	14.542	2.34
Activated partial thromboplastin time (s)	98	26.1	200	79.779	44.62
INR	98	0.9	3	1.132	0.25
Anti-Xa levels (U/mL)	97	0.05	1.2	0.4381	0.24
TEG-R (min)	102	5.2	82.8	32.464	19.77
TEG-alpha angle	99	5.9	71.8	28.83	18
TEG-MA	98	10	75	46.002	18.08
TEG R (heparinase) (min)	102	5.1	34.5	8.455	3.2
TEG-K (heparinase)	102	0.8	12	2.029	1.12
TEG-α angle (heparinase)	102	17.8	74.4	63.306	7.3
TEG-MA (heparinase)	102	45.1	73	59.696	6.03
TEG-G (heparinase)	100	4.1	13.5	7.712	2.01
Platelet inhibition-ADP (%)	90	0	100	41.113	33.73
Platelet inhibition-AA (%)	91	0	100	43.69	37.05
Platelet count (k/μL)	131	77	451	267.05	89.6
Platelet volume	121	6.8	10.1	8.46	0.69
Heparin dose (units/kg per hour)	131	15	46	33.66	7.15

Summary of data are presented as number of individual data points (n) with value ranges, mean value and standard deviation given. TEG values without heparinase are represented by R (reaction time), ANGLE (alpha-angle), MA (mean amplitude). TEG values with heparinase are noted as RHEP, KHEP (K = coagulation time), ANGLEHEP, MAHEP and GAHEP (GA = overall clot strength). Percent of platelet inhibition via the AA and ADP pathways are shown. The range of administered heparin dose at the time of laboratory value collection is also presented. AA: Arachidonic acid; ADP: Adenosine phosphate; PT: Prothrombin time; aPTT: Activated thromboplastin time; INR: International normalized ratio.

Table 3 Correlation matrix between tests

	aPTTcorrelationcoefficient	P	Anti-Xacorrelationcoefficient	P	R-TEGcorrelationcoefficient	P
aPTT	1		0.71	< 0.001	0.65	< 0.001
Anti Xa	0.71	< 0.001	1		0.54	< 0.001
R-TEG	0.65	< 0.001	0.54	< 0.001	1

Spearman correlation analyses were used to determine the degree of correlation between aPTT, anti-Xa and R values (R-TEG). aPTT: Activated thromboplastin time; TEG: Thromboelastogram.