Preliminary experience of a predictive model to define rectal volume and rectal dose during the treatment of prostate cancer.

OBJECTIVES: The aim of this study was to define a method to evaluate the total dose delivered to the rectum during the whole treatment course in six patients undergoing irradiation for prostate cancer using an offline definition of organ motion with images from a cone beam CT (CBCT) scanner available on a commercial linear accelerator. METHODS: Patient set-up was verified using a volumetric three-dimensional CBCT scanner; 9-14 CBCT scans were obtained for each patient. Images were transferred to a commercial treatment planning system for offline organ motion analysis. The shape of the rectums were used to obtain a mean dose-volume histogram (), which was the average of the DVHs of the rectums as they appeared in each verification CBCT. A geometric model of an average rectum (AR) was produced using the rectal contours delineated on the CBCT scans (DVH(AR)). To check whether the first week of treatment was representative of the whole treatment course, we evaluated the DVHs related to only the first five CBCT scans ( and DVH(AR5)). Finally, the influence of a dietary protocol on the goodness of our results was considered. RESULTS: In all six patients the original rectal DVH for the planning CT scan showed higher values than all DVHs. CONCLUSION: Although the application of the model to a larger set of patients is necessary to confirm this trend, reconstruction of a representative volume of the rectum throughout the entire treatment course seems feasible.

Reduction of blood coagulation and monocyte-platelet interaction following the use of a minimal extracorporeal circulation system (Synergy) in coronary artery bypass grafting (CABG).

Cardiovascular surgery with cardiopulmonary bypass (CPB) induces activation of blood coagulation and systemic inflammation involved in post-operative complications. Our study evaluated the impact of the minimal extracorporeal circulation (mini-CPB) system (Synergy, Sorin Group) on these functional aspects. Twenty patients were randomly assigned to standard CPB (n = 10) or to Synergy (n = 10). Platelet expression of PAC-1, and monocyte/granulocyte-platelet conjugates were evaluated by flow cytometry. A leukocyte-platelet adhesion index was calculated after cell number normalization. ELISAs were performed to measure IL-6 and TNF-alpha, thrombin-antithrombin III complexes (TAT), prothrombin fragments (F1+2), beta-thromboglobulin (beta-TG) and sP-selectin (sCD62P). Blood samples were drawn at the time of anesthesia (T1), at the end of CPB (T2), and at 4 (T3) and 24 hours (T4) after weaning from CPB. All patients were similar for clinical characteristics. When compared to standard CPB, the Synergy showed lower levels of the monocyte-platelet adhesion index at T2 (0.023 +/- 0.005 vs 0.063 +/- 0.013, P = 0.0092) and T4 (0.031 +/- 0.003 vs 0.055 +/- 0.005, P = 0.0017), TAT complexes at T2 (27.175 +/- 5.967 vs 86.592 +/- 5.415, P = 0.0005) and T3 (26.977 +/- 2.468 vs 45.146 +/- 4.365, P = 0.0041), F1+2 fragments at T2 (2.222 +/- 0.226 vs 4.249 +/- 0.292, P = 0.0009), and sP-selectin at T3 (115.17 +/- 19.623 vs 169.554 +/- 19.709, P = 0.0703) and T4 (108.542 +/- 6.429 vs 140.799 +/- 14.771, P = 0.0833). In summary, the Synergy exhibited a lower post-operative activation of blood coagulation, together with a reduced interaction between circulating monocytes and platelets.

Topical use of tranexamic acid in coronary artery bypass operations: a double-blind, prospective, randomized, placebo-controlled study.

OBJECTIVES: We sought to investigate the effect of topical application of tranexamic acid into the pericardial cavity in reducing postoperative blood loss in coronary artery surgery. METHODS: A prospective, randomized, double-blind investigation with parallel groups was performed. Forty consecutive patients undergoing primary coronary surgery were randomly assigned to group 1 (tranexamic acid group) or group 2 (placebo group). Tranexamic acid (1 g in 100 mL of saline solution) or placebo was poured into the pericardial cavity and over the mediastinal tissues before sternal closure. The drainage of mediastinal blood was measured hourly. RESULTS: Chest tube drainage in the first 24 hours was 485 +/- 166 mL in the tranexamic acid group and 641 +/- 184 mL in the placebo group (P =.01). Total postoperative blood loss was 573 +/- 164 mL and 739 +/- 228 mL, respectively (P =.01). The use of banked donor blood products was not significantly different between the two groups. Tranexamic acid could not be detected in any of the blood samples blindly collected from 24 patients to verify whether any systemic absorption of the drug occurred. There were no deaths in either group. None of the patients required reoperation for bleeding. CONCLUSIONS: Topical application of tranexamic acid into the pericardial cavity after cardiopulmonary bypass in patients undergoing primary coronary bypass operations significantly reduces postoperative bleeding. Further studies must be carried out to clarify whether a more pronounced effect on both bleeding and blood products requirement might be seen in procedures with a higher risk of bleeding.

[The radial artery in coronary surgery: the midterm clinical and angiographic results and the variation in vasoreactivity over time]. / L'arteria radiale in chirurgia coronarica: risultati clinici ed angiografici a medio termine e variazione della vasoreattività nel tempo.

OBJECTIVE: To evaluate the mid-term angiographic results of radial artery grafts used for myocardial revascularization. METHODS: The first 68 consecutive surviving patients who received a radial artery graft proximally anastomosed to the aorta at our institution were restudied in a five-year follow-up (mean 59 +/- 6.5 months); 48 of these patients had already undergone an early angiographic examination. The response of the radial artery to the endovascular infusion of serotonin was evaluated one and five years after surgery and the mid-term status of the radial artery grafts was correlated with the degree of stenosis of the target vessel and with the Ca(++)-channel-blocker therapy. RESULTS: The patency and perfect patency rates of the radial artery five years after the operation were 91.9 and 87.0% respectively. All radial artery grafts that were patent early after surgery remained patent at mid-term follow-up and in seven patients early parietal irregularities disappeared after five years. The early propensity to graft spasm after serotonin challenge decreased markedly at mid-term follow-up. The continued use of Ca(++)-antagonists after the first postoperative year did not affect the status of the radial artery graft, whereas the severity of target-vessel stenosis markedly influenced the angiographic results. CONCLUSIONS: The mid-term angiographic results of RA grafts used for myocardial revascularization are excellent. A correct surgical indication is essential, whereas continued therapy with Ca(++)-antagonists after the first year does not influence the mid-term angiographic results.