Discussion
According to the present study, OC is associated with higher transfusion rate of blood components than LC. In the current data, 13 % of the OC patients and 1.3 % of LC patients received RBC transfusion. Also, for the other blood component products (PLTs, FFP and Octaplas®), the transfusion rates were significantly higher in the OC group. In addition to more invasive nature of OC, this may be partly due to the fact that the OC patients were older and thus more likely to receive anticoagulant therapy. The OC patients also underwent emergent operation more often than LC patients.
The lack of systemic classification of bleeding complications in LC makes the comparison of the results of the current study to the existing body of literature challenging. Some authors have assessed and reported only major vascular injuries (usually including injuries to the aorta and its main branches, vena cava and the portal vein), while life-threatening bleeding may also occur from the liver bed. Vascular injuries may also have been reported as trocar injuries. Other authors have documented bleeding requiring either transfusion or reoperation or less serious intraoperative and postoperative bleeding. Intraoperative and postoperative bleeding may have been further divided into internal (peritoneal cavity of retroperitoneal space) and external (abdominal wall) bleeding based on the localization.
The incidence of postoperative intra-abdominal bleeding has been reported to be 0.69–1.05 % in LC patients. In the analysis of 10 174 LCs by Z'graggen and co-workers, bleeding was also the most frequent intraoperative complication occurring in 1,97 % of the cases. In a Finnish series of 1581 LCs, incidence of all bleeding complications was 1.1 % and bleeding complications requiring reoperation occurred in 0.5 % of the cases. Roslyn and co-workers reported the overall incidence of bleeding complications of 0.4 % in the analysis of 42 474 OCs. In their series, intraoperative bleeding was also associated with a significant risk of death. In the current study, the data on massive transfusions indicates, that major bleeding remains a rare but serious complication of cholecystectomy with significant associated mortality. New advantages of technology, such as ultrasonic dissection and anticoagulant pads may decrease the bleeding complications in future register studies.
Previous studies have hardly reported the need of blood transfusion related to LCs and OCs. However, few publications reporting transfusion rates for general laparoscopic operations exist. In their analysis of 14 243 general laparoscopic operations (of which 59.4 % were LCs), Schäfer and co-workers reported 33 patients with intraoperative and 63 patients with postoperative bleeding complications requiring blood transfusion. The overall rate of bleeding complications requiring transfusion was 0.7 % in their series, the overall rate of bleeding complications (including minor bleeding such as laceration of minor vessels) being 4.1 %. Opitz and co-workers reported an overall bleeding rate of 3.3 % in an LC-dominant (52 %) sample of 43 028 of general laparoscopic operations. In their study, the higher transfusion rate (24 %) was observed in patients with postoperative bleeding compared to patients with intraoperative bleeding (7 %, p < 0.0001).
Transfusion rates for LC in this study, 1.3 % RBCs and 1.6 % for all blood component products, are higher than reported for above mentioned LC-dominant general laparoscopy samples. About 30 % of patients in these two laparoscopy samples underwent herniotomy or appendectomy, both procedures that do not involve the dissection of the liver bed, a potent source of bleeding. This may explain in part the higher observed transfusion rate in this study. In addition, a previous report shows that the rate of RBC usage in Finland has been rather high compared to that in other European countries partly, because the sufficient blood supply has not limited the availability of blood component products and because of the low risk for transfusion-transmitted viral infections in Finland.
Bleeding data of our transfusion register and particular platelet transfusions in the patients undergoing general surgery has been published earlier. One-fourth (27.1 %) of the surgery-related platelet transfusions went to patients who had alimentary tract operations, 11 % in orthopedic surgery, but mainly to patients undergoing cardiac operations. Surgery-related bleeding complications and platelet transfusions occurred most frequently between the age groups 50 and 79 years, and more often in males than females. In obstetric procedures, platelets were used in 267/17916 (1.5 %) operations.
There are several limitations in this study. One is the register-based nature of this study. First, the current data covers only the transfusions associated with the hospital stay during which the cholecystectomy took place, and thus cases of delayed postoperative bleeding requiring transfusion may have been missed. Second, reoperations are not reported. Major bleeding is often defined as a bleeding complication requiring transfusion or a reoperation. However, there was a substantial number of missing diagnosis codes for 60-day reoperations in the data. Combined with the lack of uniform practice for diagnosis and procedure code entries, when a complication occurs, it would have been highly biased to report the rate of reoperations, especially those performed because of bleeding. Third, conversions could not be identified from the data due to the lack of a separate procedure code for conversion in NCSP. Consequently, cases of LC converted into OC are included in the OC group in this study. Since bleeding is a frequent reason for conversion, conversions would have been deserved to be analyzed as a group of its own.
In addition, because of the register-based nature of this study, patient-specific predisposing factors for bleeding complications, such as anticoagulant or anti-platelet therapy or liver cirrhosis, could not be identified from the available data. A high incidence of post-operative bleeding has been reported in patients on long-term anticoagulant therapy undergoing LC, even when the anticoagulant therapy was discontinued long enough for the international normalized ratio to be normalized. Additionally, in a Swedish register study, systemic thromboprophylaxis increased the risk of bleeding complications in LC, but the incidence of thromboembolic complication was not significantly reduced. On the other hand, the association between anti-platelet therapy and bleeding complications is controversial, especially in the case of emergency surgery. In a recent retrospective case–control study, long-term aspirin anti-platelet therapy was not associated with increased risk of bleeding complications in emergent LC for acute cholecystitis. Based on the results, the authors concluded that long-term aspirin use should not be used as an independent factor to delay an emergent LC. The impact of the new non-vitamin K antagonist oral anticoagulants on the incidence of bleeding complications associated with LC remains an interesting topic for future research.