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VTE and thromboprophylaxis in patients with IPD - the SPATA-DVT Study
Figure 1. Use of thromboprophylaxis in different types of surgery in the inherited platelet disorder population.
Discussion
Our data show that the current use of thromboprophy- laxis in patients with IPD undergoing surgery at VTE-risk is low, probably due to fear of bleeding complications and to the belief that these patients are protected from VTE. In the general population the prevalence of phar- macologic thromboprophylaxis use has been estimated to be 17.7% in neurosurgery, 27% in abdominal surgery, 50% in gynecological surgery, 52% in cardiovascular sur- gery, 67% in urological surgery, 91% in orthopedic sur- gery, and 98% in thoracic surgery,35-38 while in our IPD population it was 0% in cardiovascular surgery, 9% in abdominal surgery, 11% in neuro and spinal surgery, 21.8% in gynecological surgery, 31.7% in orthopedic sur- gery, 50% in urological surgery, and 77% in thoracic sur- gery. In IPD patients, as expected, the most frequently employed thromboprophylaxis was mechanical, princi- pally with elastic compression stockings. In otherwise healthy subjects undergoing general and orthopedic sur- gery the use of compression stockings was shown to exert a significant protective effect against VTE com- pared with no stockings (9% vs. 21%; OR 0.35, 95% CI: 0.28-0.43).39 In our IPD population this approach seemed to be effective, as no patients using post-surgery elastic compression stockings developed thrombosis, including patients at high risk based on the Caprini score.
In the general population, the risk of surgery-associat- ed VTE in patients not undergoing thromboprophylaxis is strongly dependent on the Caprini score, with an inci- dence lower than 0.5% when the score is 0, 3% when the score is 1-2, 5% when the score is 3-4, and ≥ 6% when the score is ≥5.11,33,40 In our IPD population not receiving thromboprophylaxis, no VTE was observed in patients with a Caprini score <5 while in patients with a Caprini score ≥5 symptomatic VTE occurred in 4.7% of the procedures. These data could suggest that the inci- dence of surgery-associated symptomatic VTE is indeed
lower in patients with IPD that in healthy controls, at least when the Caprini score is not high. The ACCP guidelines classify surgical interventions in three groups depending on the risk of developing VTE: low risk (<10%), including minor surgery and interventions not requiring patient immobilization, moderate risk (10- 40%), including gynecological and urological open sur- gery, and high risk (risk up to 80%), including hip or knee arthroplasty, hip fracture surgery, spinal cord injury and procedures associated with high bleeding risk.3 In our IPD patients, in the high-risk group3 58% of the proce- dures (21 interventions) were performed without pro- phylaxis and 9.5% of these were followed by VTE, while no VTE events were observed in moderate or low-risk procedures carried out without thromboprophylaxis. Of the two thromboembolic events recorded, one was observed in a GT patient undergoing a femoral vein catheter insertion and the other in a bBSS patient under- going mitral valve surgery, both with a high individual VTE-risk (Caprini score of 8 and 12, respectively) and not receiving any thromboprophylaxis. Interestingly, the lat- ter is, to our knowledge, the first case of VTE described in a bBSS patient. Pharmacologic thromboprophylaxis with LMWH was adopted in only 10% of all surgical procedures at VTE-risk in our IPD population. The use of thromboprophylaxis with LMWH increased over the observation period covered by the study, reflecting the increased awareness of the thrombotic risk of surgical procedures and of the efficacy of pharmacologic throm- boprophylaxis. When heparin thromboprophylaxis was applied, its use did not seem to be guided by the assess- ment of the individual bleeding risk, but rather by the thromboembolic risk. Indeed, the Caprini score was strongly and independently associated with heparin use in our case series. No VTE was observed in patients undergoing LMWH prophylaxis, including in those belonging to the highest VTE-risk categories according to both the Caprini and procedure-related VTE scores.
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