Prevention of SSI in Cardiac Surgery by Using Intraoperative Measures for High-Risk Patients as Standard Precautions against Mediastinitis / 日本心臓血管外科学会雑誌

Background : Risk factors for surgical site infection (SSI) are thought to include poorly controlled diabetes mellitus, dialysis, and a long operating time, but patients without risk factors can also develop infection. Therefore, it is possible that SSI could be prevented by routinely using the precautions against SSI developed for high-risk patients. We investigated the route and pathogenetic mechanism of mediastinitis, which is the most frequent SSI after cardiac surgery. We hypothesized that mediastinitis occurred when the deep sternal marrow was contaminated by skin bacteria. Based on this hypothesis, we investigated the efficacy of various intraoperative prophylactic methods for preventing mediastinitis. Methods : We evaluated 658 patients undergoing cardiac surgery at our institution between April 2011 and July 2016. They were classified into two groups. Group C comprised 406 patients who received standard insertion of a sternal retractor after sternotomy. Group S was 252 patients in whom a retractor was inserted after covering the sternal marrow with oxidized cellulose hemostats and belt-like thin towels, with surplus parts of the towels being used to fill subcutaneous dead space at the superior and inferior margins of the midline wound. We investigated the following 10 risk factors for mediastinitis: diabetes (HbA1c≥7.5), renal failure (Cr≥2), smoking, obesity (BMI≥30), reoperation, urgent/emergency operation, intubation in the preoperative period, long operating time (≥8 h), reopening the chest for hemostasis, and coronary artery bypass grafting (CABG). Factors associated with mediastinitis were determined using univariate modeling analysis followed by multi-variate logistic regression analysis. Results : Mediastinitis occurred in 13 patients (2.0%). The significant risk factor for mediastinitis were urgent/emergency operation and CABG, but 1 patient had no risk factors. A univariate analysis showed statistical significance in CABG, presence of maneuver covering the sternal marrow, JapanSCORE-II in mortality and deep sternum infection (DSI). Reopening the chest for hemostasis, CABG, aortic aneurysm, plural risk factors, and JapanSCORE-II in DSI were identified as a risk factor by multiple logistic regression, not all factors showed a significant difference. Mediastinitis only occurred in group C, and it was significantly less frequent in group S with additional precautions against infection including propensity score matching analysis (p<0.05). Conclusion : When the bone marrow of the transected sternum was covered tightly to protect it from contamination by skin bacteria during cardiac surgery, the frequency of postoperative mediastinitis was significantly reduced.

Tricuspid Valve Replacement for a Patient with Corrected Congenital Transposition of the Great Vessels and Protein C Deficiency / 日本心臓血管外科学会雑誌

Protein C (PC) deficiency is an inherited thrombotic disorder with a prevalence of 0.19% among the general population. PC deficiency is associated with an increased risk of thrombosis when other risk factors are present, such as trauma, surgery, or infection, and is an important cause of mechanical valve thrombosis. We performed tricuspid valve replacement with a 29mm Carpentier-Edwards Perimount valve in a 20-year-old man with PC deficiency. The patient had corrected transposition of the great vessels with severe tricuspid insufficiency, as well as a history of cerebral infarction. In the perioperative period, we used only heparin sodium as the anticoagulant. When we restarted administration of warfarin, changing over from heparin, transient increases of serum plasmin inhibitor-plasmin complex (PIC) and thrombin antithrombin complex (TAT) levels were observed. Despite an increased dose of heparin, an appropriate activated partial thromboplastin time (APTT) was not obtained. This suggested a hypercoagulatory state, but the postoperative course was uneventful. Management of perioperative anticoagulation, prevention of late thrombotic events, and prosthetic valve selection in this particular situation are discussed.

A Case of Marfan's Syndrome with Acute Aortic Dissection during Pregnancy / 日本心臓血管外科学会雑誌

We present a case of Marfan's syndrome with acute aortic dissection during the trimester of her pregnancy, who underwent a Bentall operation 2 days after emergency cesarean section. A 24-year-old woman during the 31st week of pregnancy visited our emergency room due to sudden onset of chest and back pain, though she had no abnormality until this event. Because of her tall height, spider fingers, positive wrist sign, visual disorder and scoliosis, she was given a diagnosis of Marfan's syndrome. Enhanced CT and cardiac ultrasonography revealed that she was suffering from acute aortic dissection with annulo-aortic ectasia. Since it was difficult for her to continue with her pregnancy, she underwent emergency cesarean section and gave birth to a male baby weighted 1, 706g. Although there was little likelifood of early thrombus formation in the false lumen or significant aortic regurgitation indicating an emergency operation, fear of massive bleeding from her uterus and the exfoliated surface of the placenta after cesarean section required an observation period of 2 days. We performed a Bentall operation successfully after careful sedation, ventilation and blood pressure control for 2 days.

A Case of Mitral Valve Replacement with Rupture of the Left Ventricle / 日本心臓血管外科学会雑誌

A 56-year-old woman suffering from mitral stenosis had underwent PTMC (percutaneous transvenous mitral commissurotomy) at age 46. After she developed congestive heart failure, mitral valve replacement (MVR) with Carbomedics 29M and tricuspid annuloplasty (TAP) was carried out. Four hours after admission to the ICU, massive bleeding was noticed. Cardiopulmonary bypass was restarted in the operating room. Laceration and hematoma were found at the posterolateral wall of the left ventricle. Under cardiac arrest with removal of the prosthetic valve, an internal tear was detected about 2cm below the anterolateral commissure (Miller Type III). The tear was covered with a horse pericardial patch (2×3cm) using 6-0 running sutures with reinforcement with gelatin-resorcine-formaline (GRF) glue between the laceration and the patch. MVR sutures in the annulus above the ventricular tear were first passed through the annulus, the pericardial patch and then the prosthetic cuff. Additionally, an epicardial tear was covered and reinforced with the fibrin sheet, GRF glue and pericardial patch in turn. Cardiopulmonary bypass was weaned easily without bleeding. The patient was intentionally on respiratory support with sedation for 3 days. The subsequent postoperative course was uneventful.