rtin Ma

Nucleophilic carbenes and the wanzlick equilibrium: A reinvestigation

Contrary to earlier studies, mixtures of enetetramines A=A and B=B readily exchange their carbene units upon heating (100 – 175 °C) to give the cross-over olefins A=B. The absence of such exchange reactions has formerly been used as evidence against the dissociation of enetetramines into free carbenes by Lemal et al. and Winberg et al.

Pulmonary endarterectomy for chronic thromboembolic pulmonary hypertension: the Toronto experience.

BACKGROUND Pulmonary endarterectomy (PEA) is the treatment of choice for patients with chronic thromboembolic pulmonary hypertension (PH). However, this surgery remains performed in few experienced centres only. The goal of the study is to review our overall experience since the implementation of our program in August 2005. METHODS Review all patients referred to our program between August 2005 and July 2011. RESULTS Among 84 consecutive patients referred to our program, 52 patients underwent elective PEA and 6 emergency PEA. After PEA, 74% patients were extubated within 2 days, 71% were discharged from the intensive care unit within 4 days and 64% were discharged from hospital within 15 days. One patient undergoing elective surgery and 2 patients undergoing emergency surgery died within 30 days of surgery for an operative mortality of 1.9% after elective pulmonary endarterectomy and an overall operative mortality of 5.2%, when the 6 emergency operative cases were included. The total pulmonary vascular resistance decreased from 965±445 to 383±162 dynes per second per cm(-5) and was associated with significant improvement in World Health Organization/New York Heart Association (WHO/NYHA) functional class, 6 minutes walk distance, echocardiographic findings, and brain natriuretic peptide level at 6 months after PEA. After a median follow-up of 23 months (1-65 months), 3 patients had to be started on targeted PH therapy for deterioration of their (WHO/NYHA) functional class. CONCLUSIONS Elective PEA can be performed with limited risk, and results in excellent early and long-term outcome. All patients diagnosed with chronic thromboembolic PH should be referred for consideration of PEA in a specialized centre.

Feasibility of blood conservation strategies in pulmonary endarterectomy for chronic thromboembolic pulmonary hypertension

Blood transfusion requirements were reviewed for a consecutive series of 25 patients undergoing elective pulmonary endarterectomy (PEA) between August 2005 and March 2009 in our institution. Patients were divided into two groups based on the implementation of a conservative blood transfusion algorithm that combined antifibrinolytic therapy, intraoperative blood sequestration, blood salvage and lack of correction of coagulation parameters in the absence of ongoing bleeding. Despite similar perioperative coagulation profiles in the two groups, the introduction of a conservative blood transfusion algorithm was associated with a significant increase in the number of patients receiving no homologous blood products. Of 16 patients who underwent surgery after the introduction of the algorithm, nine (56%) required no homologous blood products and five (31%) required one or two units of homologous red blood cells only. The international normalized ratio normalized within six to 12 hours after discontinuation of cardiopulmonary bypass without transfusion of fresh frozen plasma or platelets in 13 of the 16 patients. In conclusion, a conservative blood transfusion strategy allows PEA to be safely performed with no or minimal blood product transfusions in a majority of patients despite deep hypothermic circulatory arrest.