Noritsugu Shiono

Insulin stimulates pyruvate dehydrogenase and protects human ventricular cardiomyocytes from simulated ischemia

UNLABELLED Impaired myocardial metabolism after cardioplegic arrest results in persistent anaerobic lactate production. Insulin may protect the heart from ischemia and reperfusion by enhancing myocardial metabolic recovery. However, the stimulation of glycolysis during ischemia may be detrimental because of an accumulation of metabolic end-products. We examined the effect of insulin on quiescent human ventricular cardiomyocytes subjected to simulated cardioplegic ischemia and reperfusion. METHODS Primary cardiomyocyte cultures were established from patients undergoing corrective repair of tetralogy of Fallot. Cells were exposed to varying concentrations of glucose and insulin during 30 minutes of stabilization in 10 mL of phosphate-buffered saline solution. Ischemia was simulated by exposing the cells to a low volume (1.5 mL) of deoxygenated phosphate-buffered saline solution for 90 minutes followed by 30 minutes of simulated reperfusion in 10 mL of normoxic phosphate-buffered saline solution. Cell viability was assessed by trypan blue exclusion. The activity of mitochondrial pyruvate dehydrogenase was measured in 3 states: stabilization, ischemia, and reperfusion. In addition intracellular lactate, adenine nucleotides, extracellular lactate, pyruvate, and acid release were measured. RESULTS Higher ambient glucose concentrations resulted in greater cellular injury although insulin-treated cells displayed less injury after ischemia and reperfusion. Insulin increased the pyruvate dehydrogenase activity by 31% in cardiomyocytes and reduced extracellular lactate production by 40%. Intracellular adenosine triphosphate was improved by 75% in cells exposed to high glucose concentrations in the presence of insulin. CONCLUSIONS Insulin protected human ventricular cardiomyocytes from ischemia and reperfusion. This protection may be due to a stimulation of pyruvate dehydrogenase activity which resulted in improved aerobic metabolism.

Clinical efficacy of heparin-bonded bypass circuits related to cytokine responses in children.

BACKGROUND Cardiopulmonary bypass (CPB) induces numerous systemic reactions. This study examined the efficacy of heparin-bonded CPB circuits on inflammatory responses and postoperative status in children. METHODS Thirty-four infants undergoing elective cardiac surgery were randomly divided into two groups: a heparin-bonded CPB group (n = 17) and a non-heparin-bonded group (n = 17). Plasma levels of the inflammatory cytokines were measured before, during, and after CPB, and postoperative status was determined by examining the respiratory index, blood loss, and the post- and preoperative body weight percent ratio. RESULTS Significant differences in tumor necrosis factor-alpha, interleukin-6, and interleukin-8 patterns were observed during and after CPB between the two groups (p < 0.01, p < 0.01, p < 0.05, respectively). All cytokines measured were significantly lower in the heparin-bonded group just after CPB (p < 0.05). There were no differences in duration of intubation, intensive care unit or hospital stay, or postoperative blood loss, but the respiratory index 3 hours after CPB and body weight percent ratio 24 and 48 hours after CPB were significantly reduced in the bonded group (p < 0.05, p < 0.01, p < 0.05, respectively). CONCLUSIONS Our findings suggest that heparin bonding of the bypass circuits affects early postoperative status and reduces cytokine responses in pediatric cardiac surgery.

The Variations in the Immunologic Features and Interleukin-6 Levels for the Surgical Treatment of Cardiac Myxomas

PurposeIn this study, we propose the existence of a relationship between cardiac myxomas and the immunologic features or interleukin-6 (IL-6), while also considering the optimal treatment of cardiac myxoma, especially “familial myxoma.”MethodsIn a 19-year period at our hospital, 20 patients underwent 21 operations for cardiac myxomas. The immunologic features and the IL-6 levels were measured pre-operatively in 13 cases and post-operatively in 10 cases. A case of “familial myxoma” was diagnosed based on molecular genetic analyses.ResultsNo patients died in the hospital. The tumor size correlated with the preoperative IL-6 and/or α1-globulin values (P < 0.05). In addition, all of the immunologic features and IL-6 levels normalized by 4 weeks after surgery. “Familial myxoma” demonstrated recurrence without showing increases in either the immunologic features, inflammatory signs, or serum IL-6 levels.ConclusionsPatients with cardiac myxoma should therefore be operated on immediately because the possibility that the tumor size might be large when IL-6 and/or α1-globulin values are high. In addition, cases of “familial myxoma” require careful observation and periodic echocardiography after surgery to identify any possible recurrence. Recently, molecular genetic analyses are therefore considered to be an important diagnostic tool for cardiac myxoma, especially “familial myxoma.” Our “familial myxoma” case demonstrated a C769T PRKAR1a mutation, which has also been observed in other cases of “familial myxoma.”

Tuberculous abdominal aortic pseudoaneurysm penetrating the left psoas muscle after BCG therapy for bladder cancer

We describe a case of a 75-year-old man with abdominal aortic and right femoral tuberculous pseudoaneurysms 32 months after intravesical bacillus Calmette-Guerin therapy for bladder cancer. These aneurysms were probably brought on by systemic infection by Mycobacterium bovis. The infrarenal aorta and right common femoral artery were successfully replaced with an in situ expanded polytetrafluoroethylene graft. Tuberculous pseudoaneurysm after bacillus Calmette-Guerin therapy for malignancy is very rare, and we review the related literature.

Optimal flow rates for integrated cardioplegia

BACKGROUND Antegrade cardioplegic delivery may be impaired by coronary occlusions, whereas retrograde delivery of cardioplegic solution may be inhomogeneous, leading to an accumulation of lactate and hydrogen ions, the products of anaerobic metabolism. Integrated cardioplegia using continuous retrograde cardioplegia and antegrade infusions into completed vein grafts washes out metabolites accumulated in regions inadequately perfused by retrograde cardioplegia alone. To determine the flow rates required to achieve the greatest washout, we compared a high flow rate (200 ml/min) to a low flow rate (100 ml/min). METHODS Twenty patients scheduled for isolated coronary bypass surgery were prospectively randomized to compare two flow rates for integrated cardioplegic protection using tepid (29 degrees C) blood cardioplegia. Arterial and coronary sinus blood samples were collected to evaluate myocardial metabolism. After antegrade arrest, cardioplegic solution was delivered by coronary sinus perfusion and simultaneous infusions into each completed vein graft at either high or low flow. RESULTS Increasing from low to high flow increased the washout of lactate and hydrogen ions during the aortic crossclamp period. Two hours after crossclamp removal, ventricular function was better in the high flow groups. CONCLUSIONS Tepid retrograde cardioplegia resulted in an accumulation of toxic metabolites. The addition of antegrade vein graft infusions at a flow rate of 100 ml/min resulted in a washout of these metabolites. A flow rate of 200 ml/min further improved this washout and resulted in improved ventricular function. An integrated approach to myocardial protection using a flow rate of 200 ml/min may improve the results of coronary bypass surgery.

Endovascular Abdominal Aortic Aneurysm Repair in Patients with Renal Transplants: Reports of Two Cases

The artery and vein of the transplanted kidney are generally anastomosed to the external iliac artery and vein, respectively. Therefore, in open abdominal artery aneurysm (AAA) repair in renal transplant patients, kidney ischemia due to a proximal aortic clamp is a serious problem. We successfully performed endovascular aneurysm repair (EVAR) of AAA without aortic clamping in two renal transplant recipient cases. The two patients were diagnosed with large AAAs following the renal transplant, and EVAR was performed. To protect the renal function, we used N-acetylcysteine premedication and hydration before the operation, and we could then reduce the iodine contrast medium by using echography of the artery during the operation. In this report, a case where EVAR with renal function protection is a useful treatment for renal transplant recipients with AAA is described.

Ventricular septal defect repair in an infant with severe pulmonary hypertension and preoperatively diagnosed left ventricular noncompaction

There are several options to address RV failure in patients after atrial switch operations. Some groups advocate the conversion from the atrial to an arterial switch operation, and others support orthotopic HTx. Although we are generally in favor of HTx, we also face the general problem of a lack of donors for patients awaiting HTx. A bridge to transplantation with different VADs has been one answer for patients whose condition deteriorates while on the waiting list, but using VADs in patients with ‘‘abnormal’’ anatomy presents a surgical challenge, especially after the Senning operation. As patients with TGA rarely show left ventricular (LV) dysfunction, the use of a univentricular VAD should be adequate for most, if not all, patients. To the best of our knowledge, there is no single report in the literature describing biventricular mechanical circulatory support in patients with ventricular failure after atrial switch operation. Installing an RV assist device is easy, because the enlarged and thickened left atrium is an optimal structure for the inflow conduit. The right ventricle may be another option for the LV assist device inflow conduit, but it requires dissection and exposure of the right ventricle and ventricular fibrillation, or even cardioplegic cardiac arrest as described by George and colleagues. However, if biventricular support should be required, installing an LV assist device might be done by cannulating the superior vena cava as the right atrium, which is ‘‘in the middle’’ of the heart and

Study of coronary artery bypass using the PAS-Port device: assessment by multidetector computed tomography.

ObjectiveThe use of automatic anastomotic devices in coronary artery bypass grafting surgery is associated with lower patency rates in comparison to conventional anastomosis methods. This is thought to be caused by graft curvature occurring after closing of the chest wall.MethodsWe evaluated 39 grafts in 28 patients who underwent off-pump coronary artery bypass surgery using the PAS-Port. After surgery, the proximal anastomotic angle of each stent, graft morphology, and patency were evaluated with axial and sagittal views.ResultsThe angle for the left anterior descending coronary artery segment was relatively obtuse on the left side of the ascending aorta, and the graft loop formation was not necessary. The angle for the left circumflex coronary artery segment was significantly acute for anastomosis from the upper left side of the ascending aorta. Because grafts are under the constraints of a large loop, graft length tended to become easily excessive or deficient. The angle for the right coronary artery segment was relatively obtuse. The space on the right side of the heart was so narrow that in some cases we had difficulty setting out the appropriate graft location to prevent graft curvature. No bending or stenosis was present in any graft, showing a patency rate of 100%.ConclusionThe short-term results of coronary bypass grafting using PAS-Port are satisfactory.

Fontan conversion with novel direct ablation after childbirth: Report of a case

A 38-year-old woman underwent atriopulmonary Fontan surgery at age 18 years and subsequently successfully delivered a girl by cesarean section at age 34. Her condition later deteriorated due to atrial tachyarrhythmia and progressed to New York Heart Association (NYHA) class IV heart failure. Her treatment, at age 36, comprised total cavopulmonary connection conversion, direct right atrial ablation with bipolar radiofrequency devices, the creation of an atrial septal defect, and placement of a dual-chamber permanent pacemaker. Three years after the conversion, her condition has improved to NYHA class I.

Evaluation of bioprosthetic valve for small aortic root in elderly patients.

The hemodynamics of stentless bioprostheses are superior to those of mechanical valves, especially for patients with a small aortic root. Between March 1999 and July 2001, we implanted 18 Freestyle stentless porcine valves using our technique of repeated division of the space by halving the distance. Seven patients received 19–21-mm valves and 11 received 23–25-mm valves. Clinical data and early and midterm outcomes of both groups were compared. The mean preoperative echocardiography gradient of the small valve group was 84.7 mm Hg, and when discharged from hospital, the mean gradient was 14.8 mm Hg. One operative death was encountered due to arrhythmia. This stentless porcine prosthesis has excellent hemodynamics and can be implanted safely and easily, even in elderly patients with a small aortic root, using our suture technique.