Carotid artery stiffness, digital endothelial function, and coronary calcium in patients with essential thrombocytosis, free of overt atherosclerotic disease

Coronary calcium burden_ Median and interquartile range are given for the Agatston score of coronary calcification, and the number of subjects with an Agatston score of > 160 is given_ The comparison between groups were tested by χ-square1- or Mann-Whitney test2

Coronary calcuim burden	ET patients (n= 40)	Control group (n= 42)	Comparison between groups (p)
2Agatston score	0.1 (0-16.85)	0 (0-8.55)	0.26
1Agatston score > 160 (yes/no)	6/34	0/42	<0.01

Endothelial function of the digital arteries - reactive hyperemia index (RHI) and estimate of vascular stiffness - augmentation index (AI)_ Means and standard deviations are given for the normally distributed RHI, medians and interquartile range are given for non-normally distributed AI_ Comparisons between groups were tested by the Student’s t-test1, or the Mann-Whitney test2

	ET patients (n= 40)	Control group (n= 42)	Comparison between groups (p)
1RHI	2.10 (0.57)	2.35 (0.62)	0.07
2AI [%]	19 (3-30)	13 (5-22)	0.38

Blood cell count and C-reactive protein (CRP)_ Mixed cells denote a composite reading for monocytes, eosinophils and basophils_ When CRP was reported as < 5 mg/L, a value of 2_5 mg/L was ascribed to the subject, therefore the CRP values are only an approximation_ Mean and standard deviation are shown for normally distributed data; median and interquartile range are given for non-normally distributed data_ The comparisons between groups were tested by Student’s t-test1, or by Mann-Whitney test2

Variable	ET patients (n= 40)	Control group (n= 42)	Comparison between groups (p)
1Red blood cells [10^12/L]	4.37 (0.67)	4.76 (0.41)	<0.01
1 Platelets [10^9/L]	509 (182)	243 (53)	<0.001
1Leukocytes [10^9/L]	7.60 (3.00)	7.02 (1.63)	0.28
1Lymphocytes [10^9/L]	1.67 (0.80)	2.23 (0.75)	<0.01
1 Neutrophils [10^9/L]	5.15 (2.48)	4.15 (1.20)	0.02
2Mixed cells [10^9/L]	0.6 (0.4-0.9)	0.6 (0.5-0.7)	0.76
2CRP [mg/L]	5.0 (2.5-8.4)	5.4 (2.5-6.1)	0.27

Asymptomatic carotid plaques, carotid β-stiffness index and estimated pulse wave velocity_ Mean and standard deviation are given for normally distributed continuous data, median and interquartile range are given for non-normally distributed continuous data and the number of subjects with a carotid plaque score of ≥2 is given_ Comparisons between groups were tested by: χ-square1, Student’s t-test2, or the Mann-Whitney test3

	ET patients (n= 40)	Control group (n= 42)	Comparison between groups (p)
3 Carotid plaque score	1 (0-1.25)	0 (0-2)	0.30
1 Carotid plaque score ≥2 (yes/no)	10/30	14/28	0.41
2β-stiffness index	7.75 (2.34)	8.44 (2.81)	0.23
2pulse wave velocity (m/s)	6.21 (1.00)	6.45 (1.04)	0.46

Cardiovascular 10-year risk estimation by the Framingham risk equations_ Median and interquartile range are shown_ Comparisons between groups were tested by the Mann-Whitney test

Framingham 10-year risk calculation (%)	ET patients(n= 40)	Control group (n= 42)	Comparison between groups (p)
CHD	7.80 (3.98-13.73)	7.20 (3.57-11.37)	0.52
MI	2.87 (1.25-6.72)	2.17 (0.77-4.73)	0.47
Stroke	2.93 (1.19-5.37)	2.59 (1.49-4.09)	0.73
CVD	14.56 (7.16 – 23.68)	12.99 (6.43-19.52)	0.84

Baseline characteristics_ Numbers of subjects are given for discrete data_ Mean and standard deviation are shown for normally distributed continuous data; median and interquartile range are given for non-normally distributed continuous data_ Comparisons between groups were tested by χ-square1, Student’s t-test2, or Mann-Whitney test3

Variable	ET patients (n= 40)	Control group (n= 42)	Comparison between groups (p)
2 Age (years)	57.1 (14.1)	58.2 (13.1)	0.71
1 Sex (M/F)	14/26	16/26	0.77
2 BMI (kg/m2)	25.4 (3.5)	27.0 (4.5)	0.07
2 Waist circumference (cm)
M	95.4 (10.4)	101.1(10.2)	0.14
F	89.7 (8.8)	89.4 (13.6)	0.92
3 Systolic blood pressure (mmHg)	139 (129-148)	136 (130-143)	0.33
3 Diastolic blood pressure (mmHg)	80 (73-89)	80 (74-87)	0.92
2Total cholesterol (mmol/l)	5.01 (1.07)	5.23 (0.83)	0.30
2LDL-cholesterol (mmol/l)	2.73 (0.77)	2.86 (0.69)	0.42
2HDL-cholesterol (mmol/l)	1.44 (0.48)	1.63 (0.48)	0.07
2Triglycerides (mmol/l)	1.82 (0.79)	1.65 (0.82)	0.33
1 Current smoking (yes/no)	5/35	3/39	0.41
1 Ever smoking (yes/no)	16/24	11/31	0.12
1Diabetes (yes/no)	3/37	0/42	0.07
3Serum glucose (mmol/l)	5.4 (4.7-6.1)	5.1 (4.8-5.6)	0.64
Kidney disease (yes/no)	0/40	0/42	-
2Serum creatinine (μmol/l)	75.7 (15.0)	75.7 (14.1)	0.99
Family history of premature CVD (yes/no)	0/40	0/42	-
1Family history of CVD (yes/no)	16/24	16/26	0.86