2 Comparison of HIT-Ab between HIT patients and Suspected HIT patients Undoubtedly, there are certain limitations in the present study. clinical prognosis and outcomes. Results In the present study, 38 suspected HIT patients, 16 HIT patients and 188 non-HIT patients were selected in the clinical setting. Among them, HIT patients were found to have prolonged cardiopulmonary bypass time (223?min on average vs. 164?min) and delayed aortic cross-clamp time (128?min on average vs. 107?min), and these differences between HIT patients and non-HIT patients were significant (value ?0.05. Results A total of 204 patients with acute type A aortic AZD4547 dissection were consecutively included and observed. They were grouped according to 4Ts scores and anti-PF4/H antibody, and Among the 38 patients with 4Ts score??4 points, and anti-PF4/H antibody ?0.4 OD, 22 patients were classified as the suspected HIT group. Sixteen patients were eventually confirmed as HIT because 4Ts score??6 points, and anti-PF4/H antibody 1.8 OD [5]. Specifically, 16 and 188 patients were assigned AZD4547 to the HIT group and the non-HIT group respectively, respectively. The results of the comparison between the two groups AZD4547 are presented in Tables?1, ?,22 and ?and3.3. Through comparison of preoperative data, no significant differences were observed in age, sex or body mass index between the HIT and non-HIT groups (valuebody mass index, diabetes mellitus, chronic obstructive pulmonary disease, left ventricular ejection fraction Table 2 Intraoperative data comparison between the HIT group and the non-HIT group valuevaluecardiopulmonary bypass, deep hypothermia circulatory arrest Table 4 Comparison of HIT and suspected HIT groups value /th /thead 4Ts score5.4??1.25.7??1.25.3??1.10.527preoperative HIT Ab (OD)0.4??0.20.5??0.10.4??0.10.651HIT Ab titer (OD)1.4??1.62.7??0.80.3??0.20.001PLT drop(%, 95 CI)70.1 (67.9?~?79.0)73.6 (67.2?~?79.4)67.9 (62.9?~?71.7)0.236Minimum PLT(109/L)44.4??16.640.9??17.247.6??20.10.076 Open in a separate window Discussion The above mentioned data were collected from patients who underwent surgery in the aorta. In our study,the incidence of HIT was 7.8%(16/204) for specific patients who underwent surgery under deep hypothermic circulatory arrest (DHCA), its really surprising. But for the patients undergoing cardiopulmonary bypass with heparin during the same period,the incidence of HIT was 1.2%(16/1364). Regarding thoracotomy, cardiopulmonary bypass is associated with the anticoagulation process of heparin. For this reason, patients with acute type A aortic dissection undergo a longer procedure and a short DHCA process during surgery. All patients in this series were exposed to a large dose of heparin, and postoperative PLTc reduction for unknown causes increases the risk for HIT development. HIT onset is not easy to perceive due to a lack of specificity in clinical manifestations, though a PLTc reduction 3?days after heparin administration is the most common. Occasionally, such a manifestation may be observed within 24?h or several months after the application of heparin [7]. The findings of the present study strengthen the awareness that HIT is a important complication AZD4547 worth causing our great attention after surgery for acute type A aortic dissection. Although the differences in preoperative data between the HIT group and the non-HIT group showed no statistical significance. Because of apparently longer extracorporeal circulation time and aortic cross-clamp time in the HIT group, the dose of heparin needs to be increased. In our study, the doses of heparin in both groups were not significantly different from each other ( em P /em ? ?0.05). The extension of the time of extracorporeal circulation may enable the body to be exposed to heparin for a longer time. Hence, achieving an appropriate ratio between heparin and PF-4 and produce pathogenic HIT antibodies becomes much more likely [8]. In this context, the time of extracorporeal circulation and aortic cross-clamp should be reduced to the greatest extent during surgery for acute type A aortic dissection. Thus, both the exposure dose of heparin and the time of exposure can be decreased. PLTc reduction induced by HIT after surgery for acute type A LRP2 aortic dissection makes it more possible to administer renal replacement therapy after acute kidney injury. The pathogenesis might involve the influence of microvascular thrombosis development because microvascular thrombosis has the potential to reduce the volume of blood flow in the kidney, further lowering the glomerular filtration rate and finally leading to acute kidney injury [9]. Although HIT increases the rate of stroke incidence, both thromboembolism and microvascular blood flow disorder are the primary reasons why the risk of stroke increases in this group. Nonetheless, further investigations are warranted to identify the effects of PLTc reduction.