Manabu Sato

Evaluation of platelet and coagulation function in different animal species using the xylum clot signature analyzer.

Platelet and coagulation function were evaluated in four different animal species with a newly developed clot signature analyzer (CSA). CSA is unique in that it simultaneously measures global platelet and coagulation function under flow using whole blood. No anticoagulant, chemical, or immunologic agent is required. Three CSA parameters are measurable: platelet mediated hemostasis time (PHT), collagen induced thrombus formation time (CITF), and clotting time (CT). Bovine, ovine, and canine species were chosen because these are the animal models most frequently used in in vivo testing of cardiovascular implants. These parameters, as well as data from whole blood platelet aggregometry (commonly used for platelet function studies because of the response to exogenous agonists), and platelet counts from these animals, were measured and compared with those in humans. In all three parameters, the canine species showed distinctively shorter time values than other species, including humans, suggesting that the dog is not an ideal animal model for the evaluation of blood-surface interactions. Ovine and human blood showed similar PHT and CT values, but CITF time values were significantly shorter in sheep than in humans. With bovine blood, PHT was most prolonged among the four species compared. CT and CITF times in calves were shorter than those in humans, although the difference in CITF time was not statistically significant. Adenosine diphosphate induced platelet aggregation showed the same order of responsiveness in four species as did CITF. It was noted that the intermeasurement variation was rather high for CSA parameters, especially in PHT, warranting caution when this parameter is used to study time-dependent changes after device implantation.

Laparoscopic Inferior Vena Cava and Right Atrial Thrombectomy Utilizing Deep Hypothermic Circulatory Arrest

BACKGROUND AND PURPOSE Surgery for renal cancer associated with a level III or IV tumor thrombus often involves cardiopulmonary bypass, deep hypothermia, and exploration of the right atrium and inferior vena cava (IVC). This major open operation necessitates a large median sternotomy incision and a midline abdominal or chevron incision. Herein, we investigate the feasibility of purely laparoscopic IVC and right atrial thrombectomy utilizing deep hypothermic circulatory arrest. MATERIALS AND METHODS In six male calves weighing 70 to 80 kg, the right common carotid artery and right internal jugular vein were cannulated for subsequent cardiopulmonary bypass. One laparoscopic team performed right radical nephrectomy and complete mobilization of the intra-abdominal IVC by a four-port approach. Simultaneously, a second laparoscopic team obtained three-port thoracoscopic access to incise the pericardium and expose the right atrium. In sequence, cardiopulmonary bypass, complete exsanguination, cardiac arrest, and core hypothermia of 18 degrees C were achieved. A coagulum thrombus was created by needle injection into the IVC. Combined laparoscopic and thoracoscopic incision, exploration, and thrombectomy of the IVC and the right atrium were then performed in a bloodless field. An angioscope was inserted inside the heart and the IVC to confirm complete thrombus clearance visually. The IVC and right atrium were then laparoscopically suture repaired, cardiopulmonary bypass was reestablished, and the animal was gradually rewarmed. Once sinus rhythm was reestablished at normal body temperature, the animal was weaned off the pump. RESULTS The mean total operative time was 494.5 minutes (range 355-705 minutes). The mean time needed to lower the core temperature was 63.5 minutes (range 50-120 minutes), and the mean time required to rewarm the animal was 101.8 minutes (range 70-130 minutes). The mean blood volume drained into the pump was 2633.3 mL (range 1400-3200 mL), and the mean estimated blood loss was 350 mL (range 200-750 mL). Reestablishment of sinus cardiac rhythm and weaning off the pump was successful in all animals prior to acute euthanasia. CONCLUSIONS Laparoscopic radical nephrectomy with thrombectomy for level III or IV tumor thrombi utilizing deep hypothermic circulatory arrest is feasible in the calf model using minimally invasive techniques exclusively. The procedure is technically complex and requires the combined efforts of expert urologic and cardiac operative teams. Survival studies are planned.

Blood compatibility of a newly developed trileaflet mechanical heart valve.

An ideal heart valve prosthesis, which has both the flow dynamic properties and blood compatibility of a tissue valve prosthesis and the durability of a mechanical prosthesis, does not exist. The Triflo trileaflet mechanical heart valve (MHV; Triflo Medical Inc., Irvine, CA) is a newly developed MHV prosthesis with the following design goals: central flow, minimal flow disturbance and stasis around the hinge region, and durability. The current study was conducted to evaluate the blood compatibility of a 29 mm Triflo MHV in the mitral position of eight calves for 5 months without any postoperative anticoagulation. Whole blood platelet aggregometry and the Xylum Clot Signature Analyzer (Xylum Corporation, Scarsdale, NY) were used to evaluate the postoperative changes in platelet and coagulation functions. Full autopsies, histological examinations of major internal organs, and scanning electron microscopy analyses of the explants were performed. Early termination occurred in two cases; one was because of valve thrombosis on the 25th day, and the other was killed because of a nonvalvular complication on the 105th day. The valve thrombosis was attributed to prolonged ventricular fibrillation at the time of valve replacement surgery. Whole blood platelet aggregometry and clot signature analyzer parameters did not show any sign of activation of platelets or the coagulation system. No hemolysis was observed. There was no macroscopic valve thrombosis or embolism observed in the remaining seven cases. Scanning electron microscopy analyses showed clean leaflet and valve ring surfaces, with only occasional minute platelet aggregations. Excellent blood compatibility of the Triflo MHV was demonstrated in this study.

Impact of transapical aortic cannulation for acute type A aortic dissection.

OBJECTIVE Early and mid-term result of transapical aortic (TAA) cannulation technique was evaluated compared with femoral artery (FA) cannulation in Acute Type A Aortic Dissection(AAAD). METHODS From January 2000 to October 2013, 80 consecutive patients with AAAD were underwent the ascending aortic replacement at Nagasaki Kouseikai Hospital. These patients were divided into two groups according to the cannulation site, FA cannulation (n = 34) and TAA cannulation (n = 46). Early and mid-term outcomes were compared between two groups. RESULT Preoperative patient characteristics were almost comparable between groups. The time from skin incision to starting cardiopulmonary bypass (CPB) was significantly shorter in the TAA group (45 ± 16 vs 23 ± 5.1 min; P <0.001). There were no significant differences in post-operative cerebral infarction in two groups (17% versus 11%; P = NS). The operative mortality rate was 8.8% in FA group and 4.3% in TAA group (P = NS). During follow up (mean, 6.8 years), survival at 3 years and 5 years was 77.4% and 71.9% in TAA group and 76.3% and 73.8% in FA group, respectively. CONCLUSION The postoperative morbidity and mortality between the two groups were almost the same. TAA cannulation for acute Type A aortic dissection is faster, easy and safe with acceptable early and mid-term outcome.

Safety and Efficacy of Low-Dose Continuous Infusion of Landiolol, an Ultra-Short-Acting β-blocker, in Cardiac Surgery

Introduction: Landiolol hydrochloride is an ultra‐short‐acting β‐blocker that is administered intravenously and has many advantages in cardiac surgery. This study was performed to examine the safety and efficacy of low‐dose landiolol continuous infusion in cardiac surgery.

Repair of a pseudoaneurysm compressing the right coronary artery in a patient with Takayasu's arteritis

Aortic pseudoaneurysms may occur following the replacement of the ascending aorta and arch in patientswith connective tissue, congenital, or atherosclerotic disease. Patients with Takayasus arteritis may also develop pseudoaneurysms due to calcification of aortic tissue. We present images of a patient with Takayasus arteritis who developed a giant pseudoaneurysm compressing the right coronary artery (RCA) following aortic arch replacement. A 57-year-old female with Takayasus arteritis, who had undergone replacement of the descending aorta and total arch replacement 21 and 10 years previously, presented with chest pain. At the time of the total arch replacement, a Hemashield graft (Maquet Cardiovascular, San Jose, CA) was placed from the sinotubular junction to just beyond the takeoff of the left subclavian artery, and each arch vessel was individually reconstructed. A chest computed tomography (CT) showed a 80 × 70-mm pseudoaneurysm at the site of the proximal graft anastomosis compressing the RCA (Figures 1A and 1B), which had not been seen on a previous surveillance CT scan 6 months earlier. The patient had elevated Creactive protein levels and was receiving prednisone, 15 mg orally each day for active Takayasus arteritis. At the time of surgery, prior to a repeat median sternotomy, cardiopulmonary bypass was established with femoral arterial and venous cannulation. A resternotomy was then performed and the heart was arrested with cold, crystalloid cardioplegia. A 50 × 30-mm pseudoaneurysmwas found at the proximal suture line of the previous graft with the native ascending aorta. The pseudoaneurysm was completely resected and the defect was repaired with a polyethylene terephthalate “J graft” patch (Japan Lifesciences, Inc., Tokyo, Japan), reinforced posteriorly with bovine pericardium (Figures 1C and 1D). Sutures were placed through the previous graft superiorly as well as the native aorta inferiorly. This patch was reinforced with another “J graft” bovine pericardial patch. The cardiopulmonary bypass time and arrest time were 161 and 40min, respectively. Thepatient tolerated theprocedurewell and apostoperativeCT scan showed no evidence of a recurrent pseudoaneurysm or any RCA compression (Figures 2A and 2B). Specimens from the previous graft and the native aorta showed evidence of aortitis but no infection. The patient has remained asymptomatic on steroids for 5 yearswithout any recurrent pseudoaneurysm formation on a recent follow-up CT scan (Figure 2C).

Aortic valve replacement with smaller valve size.

The occurrence of prosthesis-patient mismatch after aortic valve replacement with a small valve size was evaluated in 249 patients, focusing on echocardiographic data. Aortic valve pathology included regurgitation in 174 patients and stenosis in 75. Echocardiography was performed in the early and late postoperative periods. A projected effective orifice area index < 0.85 cm2ċm−2 was noted in 56 patients; values ≥ 0.85 cm2ċm−2 were found in 128. Postoperative changes in ejection fraction, left ventricular mass regression, and peak transprosthetic gradient were similar in both groups. Small prostheses (≤ 19 mm) were used in 43 patients who had significantly higher postoperative transprosthetic gradients in both the early and late periods, compared to those with larger prostheses. Our findings show that the occurrence of prosthesis-patient mismatch after aortic valve replacement is rare. Left ventricular mass regression occurred in most patients, with acceptable transprosthetic gradients.