Takehisa Abe

Rescue of Ca2+ overload-induced left ventriclur dysfunction by targeted ablation of phospholamban

In failing hearts, a deficiency in sarco(endo)plasmic reticulum Ca2+ -ATPase (SERCA)2a results in abnormal Ca2+ handling and diminished contraction. In addition, a decrease in the phosphorylation of phospholamban (PLB) has been reported. Gene transfer of antisense PLB (asPLB) can improve contractile function in the failing human myocardium. Gene transfer of SERCA2a improves survival and the energy potential in failing hearts. The aim of present study was to evaluate whether enhancement of SERCA2a function prevents acute Ca2+ overload-induced left ventricular (LV) dysfunction in rat hearts. We ablated PLB using adenoviral gene transfer of asPLB by a new and less invasive gene delivery method, which involved a percutaneous technique. Experiments were performed on 13 excised cross-circulated rat hearts: 5 rats underwent sham operations, 4 rats underwent gene transfer of the reporter gene beta-galactosidase (Ad.beta-gal), and 4 rats underwent gene transfer of asPLB (Ad.asPLB). After clearance of high Ca2+ infused into the coronary, there was LV contractile dysfunction associated with the decreased myocardial O2 consumption per beat (Vo2) intercept (equal to decreased Vo2 for Ca2+ handling in excitation-contraction coupling) of the Vo2-systolic pressure-volume area (PVA; total mechanical energy per beat) linear relation in the hearts that underwent sham operation and had been infected with Ad.beta-gal. Hearts that had been infected with Ad.asPLB were rescued from LV contractile dysfunction associated with an unchanged Vo2 intercept of the Vo2-PVA linear relation. We conclude that SERCA2a function enhanced by adenoviral gene transfer of asPLB prevents Ca2+ overload-induced LV contractile dysfunction in terms of mechanical work and especially energetics.

Aortic valve replacement in a patient with a patent internal thoracic artery graft

Myocardial protection in patients requiring a second open-heart surgical procedure after coronary artery bypass grafting, especially when there is a patent left internal thoracic artery graft to the left anterior descending coronary artery, remains controversial. We present the case of a patient in whom aortic valve replacement was undertaken 18 months after coronary artery revascularization. Unusual features included beating-heart aortic valve replacement with continuous retrograde coronary sinus perfusion and avoidance of dissection of the patent grafts, including the left internal thoracic artery and a saphenous vein graft.

Rapid Restoration of Thrombus Formation and High-Molecular-Weight von Willebrand Factor Multimers in Patients with Severe Aortic Stenosis After Valve Replacement

Aim: Patients with severe aortic stenosis (AS) may have bleeding episodes due to the loss of high-molecular-weight (HMW) von Willebrand factor multimers (VWFMs). The absence of HMW-VWFMs and bleeding tendency are usually corrected after aortic valve replacement (AVR). To investigate the process of VWFM recovery and symptoms in patients with severe AS, we analyzed changes in VWF antigen (VWF:Ag), ADAMTS13 activity (ADAMTS13:AC), and platelet thrombus formation under high shear stress conditions. Methods: Nine patients with severe AS undergoing AVR were analyzed. Results: Evident deficiency of HMW-VWFMs was observed in six patients before surgery, which was rapidly restored within 8 days after AVR. Median levels of VWF:Ag before surgery, on postoperative days (PODs) 1, 8, 15, and 22, and one year after AVR were 78.1%, 130%, 224%, 155%, 134%, and 142%, respectively. In contrast, ADAMTS13:AC was 50.5%, 35.5%, 25.5%, 25.1%, 30.3%, and 84.6%, respectively. Preoperative thrombus formation but not surface coverage was significantly lower than that on POD 22, which was considered as normal level in each patient. Compared with preoperative levels, thrombus volume was significantly lower on POD 1, but rapidly increased by POD 8. Conclusion: Bleeding tendency and loss of HMW-VWFMs observed in patients with severe AS before surgery was rapidly corrected after AVR. Instead, patients were in a VWF-predominant state between POD 8 and 22.

Regulation of perfusion pressure during cardiopulmonary bypass using sevoflurane.

In hypothermic cardiopulmonary bypass (CPB), various vasodilators are used to control the perfusion pressure. These agents, however, often decrease the pressure excessively, and the low perfusion pressure may persist until the end of CPB. In this study we evaluate the safety and characteristics of the regulation of perfusion pressure during CPB using a volatile anesthetic, sevoflurane which has an extremely low partition coefficient. Twenty adult patients who underwent cardiac surgery were studied. Sevoflurane was applied by a vaporizer inserted into the oxygenator gas supply line. Pump flows were fixed at 2.4 L/min/m2 during the hypothermic period. Sevoflurane concentration was adjusted to keep mean arterial pressure (MAP) between 40 and 70 mmHg during CPB. Hemodynamic and metabolic parameters were measured and compared to the group we previously treated with chlorpromazine. In all cases, MAP could be maintained adequately. In the sevoflurane group, systemic vascular resistance indices (SVRI) during the rewarming period and at the end of CPB were higher, and doses of norepinephrine needed at the end of CPB were significantly lower than in the chlorpromazine group. The regulation of perfusion pressure during CPB using sevoflurane was safe and could easily maintain adequate SVRI.

Experimental use of crosslinked gelatin glue for arterial hemostasis in cardiovascular surgery.

BACKGROUND Anastomotic needle hole bleeding is a frequently encountered problem in cardiovascular surgeries. OBJECTIVE To examine the feasibility of crosslinked gelatin glue as an anastomotic needle hole sealant in comparison with fibrin glue. METHODS The in vitro burst water pressures were measured for gelatin and fibrin glue sealed needle holes of expanded polytetrafluoroethylene (ePTFE) or collagen coated woven polyester grafts. For in vivo investigations, abdominal aorta-ePTFE graft anastomoses of heparinized beagle dogs were sealed by gelatin or fibrin glue and hemostatic efficacy was judged. The implanted sites were re-examined 4 weeks postoperatively. RESULTS The in vitro burst water pressures of gelatin glue sealed needle holes of both grafts were higher than those sealed by fibrin glue. For in vivo canine studies, hemostasis was successful for all gelatin glue applied suture lines, but not two out of three fibrin glue treated sites when 3-0 polypropylene suture was employed. Although adhesions of surrounding tissues were intense for all sites 4 weeks postoperatively, inflammation was more severe for the fibrin glue group compared to those of gelatin glue. CONCLUSIONS Gelatin glue was found to be an effective and safe sealant for accomplishing hemostasis of anastomotic needle holes of vascular grafts.

Aortic root replacement for Valsalva sinus aneurysm with lupus erythematosus.

A 76-year-old man with systemic lupus erythematosus was found to have an aneurysm of the right sinus of Valsalva. Aortic root replacement with a stentless bioprosthesis, using a full root technique, was successfully performed. The pathological findings of the excised aortic valve were not secondary to atherosclerosis, inflammatory or infectious disease, but seemed to be compatible with those previously reported in a case of systemic lupus erythematosus.

Gelatin Sealing Sheet for Arterial Hemostasis and Anti-adhesion in Vascular Surgery: a Dog Model Study.

BACKGROUND The bilayer gelatin sealing sheet was developed as a safe, effective, easy-to-handle and low-cost hemostatic agent. OBJECTIVE To examine the feasibility of gelatin sealing sheets using a canine arterial hemorrhage model. METHODS In vivo degradation of gelatin sealing sheets was examined by implanting subcutaneously in rats. For the hemostatic and anti-adhesion efficacy investigations, femoral arteries of dogs were pricked with syringe needle to make a small hole and a gelatin (i.e. experimental group) or fibrin glue sealing sheet (i.e. control group) was applied on the hole to stop bleeding (n=8). After discontinuation of the bleeding, the skin incisions were closed and re-examined 4 weeks postoperatively. RESULTS From the degradation study, 4 h thermally treated gelatin sheet which degraded within 3 weeks in vivo was chosen for the further hemostatic study. In all cases of gelatin and fibrin glue sealing sheets, bleeding from the needle hole on canine femoral arteries was effectively stopped. Postoperative adhesions and inflammation at the site in the experimental group were significantly less than those in the control group (P<0.01 for adhesion scores). CONCLUSIONS The gelatin sealing sheet was found to be as effective as the fibrin glue sealing sheet as a surgical hemostatic agent, and more effective in preventing postoperative adhesions.

Isolated dissecting aneurysm of the brachiocephalic artery associated with contained rupture

A 79-year-old man with no history of trauma complained of a sudden onset of headache and backache. Computed tomography showed an isolated dissecting aneurysm 4 cm in diameter associated with contained rupture at the takeoff region of the brachiocephalic artery. Surgery was performed on an emergent basis. The proximal aortic arch was successfully replaced using antegrade selective cerebral perfusion. The patient was easily weaned from cardiopulmonary bypass and recovered uneventfully.

Circumferential Acute Type an Aortic Dissection with Intimo-Intimal Intussusception: The Efficacy of Central Aortic Cannulation

An 80-year-old woman suffered from acute chest pain and then exhibited cardiogenic shock. Transthoracic echocardiography revealed severe aortic regurgitation due to the intussusception of the intima. Computed tomography also showed the intussusception of the intima into the left ventricular outflow tract over the aortic valve and dissection involving the aortic root, aortic arch, and descending thoracic aorta. During surgery, echocardiography-guided central aortic cannulation was performed for the prompt establishment of cardiopulmonary bypass. The complete intimal tear was circumferentially located in the middle level of the ascending aorta. The proximal flap was inverted into the left ventricle, and the distal flap had been pushed into the aortic arch. Graft replacement of the ascending aorta was performed successfully, and the patient had an uneventful postoperative course.

Aortic valve replacement in a patient with left ventricular noncompaction

Left ventricular noncompaction is a rare cardiac pathology that results from an arrest in endomyocardial development in early embryogenesis. With great advances in imaging modalities, this pathological entity has been noted not only in the pediatric population but also in adults. Herein we report the case of a 62-year-old woman who successfully underwent aortic valve replacement for aortic regurgitation complicated by left ventricular noncompaction.