Table 1. Clinical features of the cohort at the time of the index event.
| Male/female, N (%) | 63/118 (34.8/65.2) |
|---|---|
| Age, years, median (range) | 48 (29–74) |
| <40 years, n (%) | 51 (28.2) |
| 40–60 years, n (%) | 90 (49.7) |
| ⩾60 years, n (%) | 40 (22.1) |
| Diagnosis, N (%) | |
| PV | 67 (37.0) |
| ET | 67 (37.0) |
| PMF | 47 (26.0) |
| Years from diagnosis to index thrombosis, mean (±s.d.) | 2.01 (3.87) |
| Diagnosis at the time of index thrombosis, n (%) | 105 (58) |
| Hb gr/dl, median (range) | 13.4 (6.3–24.0) |
| Hct %, median (range) | 42.1 (22.0–70.0) |
| WBC count × 109/l, median (range) | 9.3 (3.0–50.0) |
| Platelet count × 109/l, median (range) | 424 (100–3000) |
| JAK2 mutation, N/N tested (%) | 166/178 (93.3) |
| CALR mutations, N/N tested | 4/25 (16.0) |
| MPL mutations, N/N tested | 1/28 (3.6) |
| Exon 12 mutations, N/N tested | 0/14 (0.0) |
| Abnormal karyotype, N/N tested (%) | 8/65 (12.3) |
| Microvascular disturbances, N (%) | 19 (10.5) |
| Constitutional symptoms, N (%) | 28 (15.5) |
| Palpable splenomegaly, N (%) | 119 (65.8) |
| Cm below costal margin, median (range) | 4 (1–25) |
| Localization of index thrombosis, N (%) | |
| Hepatic vein thrombosis (BCS) | 31 (17.1) |
| Portal vein thrombosis | 109 (60.3) |
| Mesenteric vein thrombosis | 18 (9.9) |
| Splenic vein thrombosis | 23 (12.7) |
| Unprovoked thrombosis, N (%) | 155 (85.6) |
| Provoked by, n (%) | 26 (14.4) |
| Oral contraceptives | 8 (4.4) |
| Hormone replacement therapy | 3 (1.7) |
| Infection | 3 (1.7) |
| Pregnancy/puerperium | 1 (0.6) |
| Cancer | 1 (0.6) |
| Surgery | 7 (3.9) |
| Liver disease | 3 (1.7) |
| Risk factors for index thrombosis | |
| History of thrombosis, N (%) | 14 (7.7) |
| History of arterial thrombosis, n (%) | 5 (2.8) |
| History of venous thrombosis, n (%) | 8 (4.4) |
| Presence of at least one vascular risk factor, N (%) | 52 (28.7) |
| Smoking habit | 19 (10.5) |
| Hypertension | 28 (15.5) |
| Dislipidemia | 7 (3.4) |
| Diabetes | 5 (2.8) |
| Presence of thrombophilia*, N/N tested (%) | 42/120 (35.0) |
| Inherited thrombophilia, N/N tested (%) | 21/120 (17.5) |
Abbreviations: BCS, Budd Chiari syndrome; ET, essential thrombocythaemia; Hb, haemoglobin; PMF, primary myelofibrosis; PV, polycythaemia vera; WBC, white blood cell.
Deficiency of antitrombin (n=1), deficiency of protein C or protein S (n=7), factor V Leiden and/or prothrombin G20210A (n=13), increased levels of homocysteine (n=16), antiphospholipids (n=6).