Kagami Miyaji

Influence of PMEA-coated bypass circuits on perioperative inflammatory response.

BACKGROUNDnPoly(2-methoxyethylacrylate) (PMEA) is a new coating material, and several experimental studies have revealed excellent biocompatibility of PMEA-coated cardiopulmonary bypass circuits. The clinical utility of the PMEA-coated circuits was compared with that of uncoated circuits, focusing on perioperative inflammatory response.nnnMETHODSnTwenty-two patients were randomized to PMEA-coated (group P; Capiox RX25; n = 11) or uncoated (group U; Capiox SX10; n = 11) circuit group, and underwent coronary artery bypass grafting and/or valve operations. The following markers, as well as clinical outcomes, were analyzed perioperatively: (a) complement activation by C3a (including C3a-desArg) concentrations; (b) leukocyte activation by polymorphonuclear-elastase concentrations; (c) acute phase inflammatory response by interleukin-6 concentrations; and (d) platelet preservation by number of platelets.nnnRESULTSnThe maximal values of C3a and polymorphonuclear-elastase were significantly lower in group P than in group U. The intergroup difference of interleukin-6 was not significant. Although preservation of platelets was significantly better in group P until 1 hour after initiating cardiopulmonary bypass, no significant intergroup difference was observed thereafter. The duration of postoperative mechanical ventilation revealed no significant intergroup difference.nnnCONCLUSIONSnThe PMEA-coated circuits exhibited better suppression of perioperative complement and leukocyte activation than the uncoated circuits. In addition, the price of the PMEA-coated circuits is the same as that of the uncoated circuits. Therefore, we judged that the clinical utility of the PMEA-coated circuits is superior to those of the uncoated circuits.

Myocardial Tactile Stiffness: A Variable of Regional Myocardial Function

OBJECTIVESnWe developed a new sensor system for in situ measurement of myocardial tactile stiffness-stiffness in a direction perpendicular to the wall-and validated its use for providing a reasonable estimation of regional myocardial function.nnnBACKGROUNDnNumerous attempts have been made to directly assess regional myocardial function. The complexity and highly invasive nature of the measuring devices have hampered their in situ application.nnnMETHODSnIn open chest mongrel dogs, myocardial tactile stiffness, ventricular pressure and ventricular volume were monitored. Under the preload reduction, these variables were measured to determine the relation between the end-systolic pressure-volume relation (ESPVR) and the end-systolic tactile stiffness-volume relation (ESSVR). The changes in myocardial tactile stiffness were monitored in the regional ischemic myocardial model and infarcted model to evaluate their usefulness as indexes of regional myocardial function.nnnRESULTSnMyocardial tactile stiffness changed cyclically and followed a time course similar to left ventricular pressure. When preload was altered, the ESSVR was as linear as the ESPVR. The slope of the ESSVR and that of the ESPVR showed a strong correlation over a wide range of contractility. These results suggest that myocardial tactile stiffness can be a good index of regional wall stress or fiber stress. End-systolic myocardial tactile stiffness of ischemic and infarcted regions decreased significantly, with a concomitant increase in end-diastolic stiffness compared with that of intact myocardium.nnnCONCLUSIONSnUsing our tactile sensor system, regional myocardial tactile stiffness of a beating heart was measured with reasonable temporal resolution. We consider myocardial tactile stiffness to be a useful index of regional myocardial function.

Myocardial tactile stiffness during acute reduction of coronary blood flow

BACKGROUNDnEvaluation of regional myocardial contractile function is of clinical importance. We have developed a new tactile sensor system for accurate measurement of myocardial stiffness in situ. We found that the myocardial stiffness measured by this sensor, which we call tactile stiffness, can be a very useful index for accurate quantification of regional myocardial function. In this study, we used a coronary stenosis model to investigate regional myocardial tactile stiffness under conditions of reduced coronary blood flow.nnnMETHODSnThe myocardial tactile stiffness, coronary blood flow, and ventricular pressure and volume, of five open chest mongrel dogs weighing 15 to 17 kg, were measured. After measuring the baseline myocardial stiffness, coronary arterial stenosis was induced with a balloon occluder.nnnRESULTSnReducing the coronary flow to 50% and 25% of the baseline level reduced the end-systolic tactile stiffness significantly from 2.20+/-0.16 g/mm2 to 2.05+/-0.20 g/mm2 (p<0.05) and from 2.21+/-0.16 g/mm2 to 1.96+/-0.18 g/mm2 (p<0.01), respectively. Reducing the flow, to 50% and 25%, increased the end-diastolic stiffness significantly from 1.29+/-0.15 g/mm2 to 1.39+/-0.14 g/mm2 (p<0.01) and from 1.30+/-0.16 g/mm2 to 1.46+/-0.14 g/mm2 (p<0.05), respectively.nnnCONCLUSIONSnWe consider that the regional myocardial tactile stiffness will be a useful index sensitive enough to detect changes in regional contractile function under conditions of reduced coronary blood flow.

The effectiveness of prestorage leukocyte-reduced red blood cell transfusion on perioperative inflammatory response with a miniaturized biocompatible bypass system

OBJECTIVEnSince 2007, the Japanese Red Cross Blood Center has provided prestorage leukocyte-reduced red blood cell concentrates in which the leukocytes were reduced soon after collection. We have established a miniaturized bypass system (140 mL) to reduce the perioperative inflammatory responses. This study was designed to reveal the effectiveness of leukocyte-reduced red blood cell concentrate transfusion on perioperative inflammatory responses in pediatric cardiac surgery.nnnMETHODSnBetween May 2006 and June 2008, 50 consecutive patients weighing less than 5 kg who underwent a surgical procedure with red blood cell concentrate transfusion using a miniaturized bypass system were reviewed retrospectively. Twenty-five patients before 2007 received stored red blood cell concentrate in which leukocytes were reduced with a filter just before transfusion (group A). After 2007, 25 patients received the prestorage leukocyte-reduced red blood cell concentrate transfusion (group B). The postoperative peak C-reactive protein level, peak white blood cell count, peak neutrophil count, percentage body weight gain, inotrope score, plasma lactate concentration, postoperative mechanical ventilation time, and length of intensive care unit stay were compared as the perioperative inflammatory response and morbidity for both groups.nnnRESULTSnThere were no significant differences in peak white blood cell count, peak neutrophil count, percentage body weight gain, and inotrope score between the groups. The peak C-reactive protein level in group A was significantly greater than that in group B (6.7 +/- 4.7 vs 4.2 +/- 3.6 mg/dL, P < .05). The lactate concentration at 12 and 24 hours after surgical intervention in group A was significantly greater than that in group B (3.1 +/- 2.5 vs 1.9 +/- 1.1 mmol/L [P < .05] and 2.2 +/- 0.2 vs 1.4 +/- 0.2 mmol/L [P < .05], respectively). The postoperative mechanical ventilation time and intensive care unit stay in group A were significantly greater than those in group B (5.9 +/- 7.4 vs 2.1 +/- 2.0 days [P < .05] and 9.8 +/- 7.9 vs 5.0 +/- 2.1 days [P < 0.05], respectively). Multivariate analyses showed that the leukocyte-reduced red blood cell concentrate transfusion reduced the peak C-reactive protein level (in milligrams per deciliter; coefficient, -2.95; 95% confidence interval [CI], -4.66 to -0.93; P = .003), postoperative mechanical ventilation time (in days; coefficient, -3.41; 95% CI, -6.07 to -0.74; P = .013), and intensive care unit stay (in days; coefficient, -4.51; 95% CI, -7.37 to -1.64; P = .003).nnnCONCLUSIONSnOur study revealed that in neonates and small infants, compared with transfusions with stored red blood cell concentrate, transfusion of leukocyte-reduced red blood cell concentrates was associated with reduced perioperative inflammatory responses and improved clinical outcomes.

Transxiphoid approach for intracardiac repair using video-assisted cardioscopy

Video-assisted cardioscopy (VAC) is a novel tool for providing clear visualization of small intracardiac structures and achieving complete repair in minimally invasive surgery. Between July 1999 and July 2000, 12 patients with atrial septal defect and ventricular septal defect underwent surgical repair using a combined procedure with the transxiphoid approach and VAC in our institution. The mean skin incision was 5.4 cm, and the postoperative courses of all the patients were uneventful without any complications. The mean hospital stay was 8.3 days and 1 patient (8.3%) needed blood products. Our experience showed the technical feasibility and acceptable surgical results of transxiphoid approach using a VAC.

Right heart mini-pump bypass for coronary artery bypass grafting: experimental study

BACKGROUNDnVisualization of the left circumflex arteries during off-pump coronary artery bypass grafting (CABG) causes hemodynamic disturbance. We investigated whether right heart mini-pump bypass (RHB), using a centrifugal pump, improved the safety of this procedure by studying the influences of different heart displacement positions, the Trendelenburg maneuver and RHB on hemodynamics.nnnMETHODnHemodynamic parameters in eight mongrel dogs (15.5-20 kg) were continuously monitored at a fixed heart rate of 80 beats/min through a conventional median sternotomy. The posterior descending artery (PDA) and left circumflex artery (LCX) were exposed using an Octopus tissue stabilizer. After evaluating the influence of the Trendelenburg maneuver on hemodynamics, a heparin-coated centrifugal pump without an oxygenator was introduced and the impact of different pump flow volumes was investigated during RHB.nnnRESULTSnLCX exposure caused significant decreases in aortic flow (to 35. 1+/-12.8%) and arterial mean pressure (to 66.1+/-9.3%) compared with baseline (P<0.001). In contrast to PDA exposure, values remained significantly decreased during the Trendelenburg maneuver. On the contrary, RHB significantly improved the hemodynamic impairments caused by both heart displacement procedures, especially LCX exposure, although 100% pump flow significantly increased left atrial pressure to 131.3+/-19.5% (P<0.01).nnnCONCLUSIONnExposure of the LCX caused severe hemodynamic deterioration, which was not fully reversed by the Trendelenburg maneuver. In contrast, RHB significantly improved hemodynamics, and therefore this technique can be beneficial for CABG of LCX in the limited cases.

Video-Assisted Cardioscopy for Infectious Endocarditis

AbstractWe successfully resected vegetation of infectious endocarditis in right ventricular outflow tract using a video-assisted cardioscopy without ventriculotomy. Video-assisted cardioscopy provided clear and precise visualization of vegetation on the anterior wall of right ventricular outflow. This technique is effective to visualize remote intra-cardiac structures, and to facilitate repairs, while avoiding the need for extended cardiac incisions.n

Successful conduit repair using aortic homograft in a jehovah's witness child

A 10-year-old female child of the Jehovahs Witness faith presented with congenitally corrected transposition of the great arteries (S,L,L), pulmonary atresia, and a ventricular septal defect. A successful surgical correction was performed using an aortic homograft as a valved extracardiac conduit without the use of homologous blood or blood products. We used permanent splinting of the sternum with a methyl methacrylate resin plate to prevent compression of the conduit.

Cardiac function evaluated by transesophageal echocardiography during cardiopulmonary bypass

OBJECTIVEnTo evaluate cardiac function at cardiopulmonary bypass weaning, we applied a new technique clinically to determine the approximated Emax without using a conductance catheter.nnnMETHODSnSubjects were 5 patients. The left ventricular end-systolic pressure was obtained by overlaying the radial arterial pressure curve on the left ventricular pressure curve. Left ventricular end-systolic volume was assessed by a transesophageal echographic apparatus. At cardiopulmonary bypass weaning, volume loading was applied to increase left atrial pressure by a few mmHg while fixing the pump flow rate at half flow. Changes in left ventricular end-systolic volume and approximated left ventricular end-systolic pressure for total heart beat were plotted during this period, and the gradient of the regression line was taken as approximated Emax.nnnRESULTSnApproximated Emax ranged from 1.29 to 3.28 (mean 2.13 +/- 0.72), and its correlation coefficient was 0.80 +/- 0.06.nnnCONCLUSIONnOur new technique is useful in evaluating cardiac function during cardiopulmonary bypass.

Right heart bypass for left circumflex coronary artery bypass grafting.

Abstract Displacement of the heart to expose the left circumflex artery (LCX) causes hemodynamic disturbance during off-pump coronary artery bypass grafting (CABG). We applied right heart bypass (RHB) using a heparin-coated centrifugal pump without an oxygenator in an attempt to stabilize the hemodynamics. Five mongrel dogs (15.5–20 kg) were used. Hemodynamic parameters were continuously monitored at a fixed rate of 80 beats/min. The LCX was exposed with the use of an Octopus Tissue Stabilizer. After baseline data were obtained, each dog was placed in the Trendelenburg position. Finally, RHB was established with different pump flows. LCX exposure caused a significant decrease in aortic flow (to 33.1% ± 13.1% of the baseline value) and arterial mean pressure (to 68.3% ± 8.5%) (P < 0.001). Trendelenburg positioning caused these values to recover to 57.1% ± 6.7% and 72.5% ± 7.7%, respectively. RHB with 50% flow significantly improved the hemodynamic values, although 100% flow significantly increased LAP by 134.8% ± 19.7% (P < 0.01). Tilting of the canine heart to expose the LCX caused significant deterioration of the hemodynamic values. Trendelenburg positioning was moderately effective, and RHB very effective, in improving the hemodynamics. In a limited number of cases, an appropriate flow of RHB may provide safe hemodynamic assistance during off-pump CABG of the LCX.