Masahiko Washio

Functional recovery of hibernating myocardium after coronary bypass surgery: does it coincide with improvement in perfusion?

To determine the relationship between functional recovery and improvement in perfusion after coronary artery bypass graft surgery (CABG), 49 patients were studied. Radionuclide angiography was performed before, 1 month after, and 6 to 12 months after CABG to evaluate regional wall motion. Exercise thallium-201 myocardial perfusion imaging was done before and 1 month after CABG to assess regional perfusion. Preoperative asynergy was observed in 108 segments, and 74 of them showed an improvement in wall motion 1 month after CABG (segment A). Sixty-six of these segments (89%) were associated with an improvement in perfusion. Eight segments that had not improved 1 month after CABG demonstrated a delayed recovery of wall motion 6 to 12 months after CABG (segment B). However, seven of eight segments (88%) already showed an improvement in perfusion 1 month after CABG. A total of 82 segments exhibited functional recovery after CABG and were considered hibernating segments. In the preoperative study segment B more frequently had areas of akinesis or dyskinesis than segment A (75% vs 34%, p less than 0.05). The mean percent thallium-201 uptake in segment B was lower than that in segment A (74% +/- 9% vs 83% +/- 8%, p less than 0.05). Functional recovery of hibernating myocardium usually coincided with an improvement in perfusion. However, delayed functional recovery after reperfusion was observed in some instances. Severe asynergy and severe thallium-201 defects were more frequently observed in these segments with delayed recovery. Hibernating myocardium might remain stunned during those recovery periods.

The hemostatic effect of deacetylated chitin membrane on peritoneal injury in rabbit model

In this study, we determined the effect of 80% deacetylated chitin (DAC-80) membrane on postsurgical bleeding after visceral and parietal peritoneal abrasion. Japanese white rabbits underwent a midline laparotomy followed either by a bilateral peritoneal sidewall abrasion (4×4 cm) or an abrasion of liver surface (3×2 cm). The injured surface was then covered with a 0.2 mm thick DAC-80 membrane. On postsurgical day 2, the rabbits were sacrificed and the amounts of postsurgical bleeding was determined by quantitating the number of red blood cells recovered in 50 ml peritoneal lavage fluid. The DAC-80 membrane was found to reduce postsurgical bleeding after the abrasion of liver surface (treated with DAC-80 membrane: 2.9±0.8; control: 24.6±5.9×108 cells/peritoneal cavity, P<0.005). This same hemostatic activity was not observed after application in the peritoneal sidewall abrasion model. We also measured plasminogen activator activity (PA) and urokinase inhibitory (PAI) activity in the spent culture media of macrophages recovered from the postsurgical peritoneal exudate. The DAC-80 membrane reduced the PA secretion from postsurgical macrophages after liver surface abrasion (treated with DAC-80: 2.8±0.7; control: 3.9±0.9 mPU/ml). The DAC-80 membrane also showed similar effects on PA secretion after peritoneal sidewall abrasion. No significant effects were found in the secretion of PAI by postsurgical macrophages in both surgical models.These findings suggest that the DAC-80 membrane may have hemostatic activity through the modulation of fibrinolytic activity of peritoneal exudative macrophages.

A cardiac myocyte culture system as an in vitro experimental model for the evaluation of hypothermic preservation

In cardiac transplantation, the donor heart is exposed to severe hypothermic and ischemic conditions. The purpose of the present study was to evaluate the functional and biochemical effects on cardiac myocytes cultured under hypothermic conditions. Cardiac myocytes were isolated from neonatal rat ventricles and cultured for 4 days, then incubated (1.5×106 myocytes/culture flask) for 24 h in media at 4, 10, 15, 20, and 37°C. In addition, myocytes were incubated at 4°C for 6, 12, 18, 24, 36, and 48 h. After each incubation, creatine phosphokinase (CPK) and lactate dehydrogenase (LDH) were measured and the myocytes then cultured for an additional 24 h at 37°C to evaluate the recovery of the myocyte beating rate. The recovery ratio of the myocyte beating rate following 24 h of varying temperature incubations was complete for the 10, 15, 20, and 37°C groups, although it was markedly decreased in the 4°C group, at 25.1% of the control; taken as the beating rate prior to hypothermic incubation. The release of CPK and LDH in the 4°C group showed a three-fold increase compared to the other four groups, with a CPK of 147.2 mIU/flask and a LDH of 487.5 mIU/flask. The recovery of the beating rate for varying time incubations at 4°C was complete for the 6- and 12-h groups, but decreased significantly in the other four groups, being 59.0% at 18 h, 28.2% at 24 h, 16.3% at 36 h, and 0% at 48 h. The CPK and LDH levels increased gradually over 24 h, then markedly at 36 and 48 h, to 301.3 and 940.5 at 36 h, and 1143.6 and 1942.9 at 48 h, respectively. Thus, 4°C hypothermia induced myocyte injury both functionally and biochemically which increased with the incubation time.

Pulsatile low-flow perfusion for enhanced cerebral protection

We examined the oxygen tension, carbon dioxide tension, and pH in canine brains under profound hypothermia to evaluate the effects of perfusion (circulatory arrest for 1 hour; 25 and 50 mL.kg-1 x min-1 for 2 hours) with and without pulsatile assistance. The effects of pulsatile flow on cerebral blood flow and metabolism were also evaluated in dogs supported by low-flow perfusion (25 mL.kg-1 x min-1) for 2 hours. Profound hypoxia occurred in the brain after 20 to 60 minutes of circulatory arrest. Brain tissue acidosis with hypercapnia was moderated by perfusion at a rate of flow of 50 mL.kg-1 x min-1. Pulsatile low-flow perfusion (25 mL.kg-1 x min-1) moderated cerebral hypercapnia and made the cerebral metabolism aerobic without affecting the total cerebral blood flow and consumption of oxygen.

A clinical study of postoperative infections following open-heart surgery: occurrence and microbiological findings in 782 cases.

A total 782 consecutive patients underwent open-heart surgery with CPB between January, 1979 and December, 1988, at the Yamagata University Hospital. We assessed the incidence of postoperative infections in relation to age, the duration of surgery and antibiotic prophylaxis, and examined the causative organisms, after which the types of infecting flora were compared between the 1st period, from 1979 to 1983 and the 2nd period, from 1984 to 1988.Postoperative infection occurred in 104 of the 782 patients (13.3 per cent); in the form of a wound infection in 41 (5.2 per cent), pneumonia in 33 (4.2 per cent), urinary tract infection in 9 (1.2 per cent), prosthetic valve endocarditis in 6 (0.8 per cent), and other infections in 15 (1.9 per cent). Patients aged under 12 months or over 60 years showed a higher incidence of infection, being 17.4 per cent and 19.2 per cent, respectively. Patients who underwent an operation of over 8 hours duration also had a significantly higher incidence compared to those whose operation time was less than 4 hours, being 32.9 per cent and 6.3 per cent, respectively (p<0.0001). There was no significant difference in the incidence of postoperative infection between patients given or not given preoperative prophylaxis. A total 123 species of organisms were isolated from the 104 patients, 52.8 per cent being gram-negative bacteria (GNB), and 43.9 per cent grampositive bacteria (GPB), and a remarkable increase in the incidence of GPB was seen in the 2nd period compared to the 1st period from 31.7 per cent to 50.0 per cent.There has been a recent increase in the number of high risk patients compromised by the severity of an underlying disease. Thus, to control infection, the surgical environment and aseptic technique seem more important than antibiotic prophylaxis.

Surgery of giant bulla with tube drainage and bronchofiberoptic bronchial occlusion

A case of emphysematous bullae and right lung cancer is presented. At first, left giant bulla was managed by minithoracotomy and tube drainage combined with bronchofiberoptic bronchial occlusion to preserve the respiratory function. Four weeks later, right lung cancer was successfully resected.

Spontaneous rupture of the descending aorta through atherosclerotic plaque: Report of a case

Spontaneous rupture of the thoracic descending aorta is rare, and uniformly fatal without surgery. We report herein the case of a man in whom such a rupture was successfully treated with emergency surgery. We believe that the rupture in this patient was most likely associated with perforation through an atherosclerotic plaque of the descending aorta and was induced by sudden hypertension.

In vitro evaluation of phosphate, bicarbonate, and hepes buffered storage solutions on hypothermic injury to immature myocytes

SummaryIn this study we evaluated cardiac myocyte viability and function under hypothermic conditions using three types of buffer solutions: phosphate buffer solution (PBS), Krebs-Henseleit bicarbonate buffer solution (KHB), and Hepes buffered minimum salt solution (MSS). As a control, normal saline solution (NSS) was used. Cardiac myocytes were isolated from neonatal rat ventricles. Myocytes (12.5 × 105 myocytes/culture flask) were then incubated at 4°C for 6, 12, 18, and 24 hours in various buffer solutions. After each incubation time, CPK and LDH were measured. The myocytes were then incubated for an additional 24 hours at 37°C to evaluate the recovery of the myocyte beating rate. Group MSS had a significantly better beating rate recovery than group NSS (control) after 18 hours (MSS, 32.7%, NSS, 0.0% of control; i.e., beating rate prior to hypothermic incubation). In contrast, group KHB showed a significantly lower recovery ratio than group NSS at 12 hours (41.0%, 78.8%, respectively), and the lowest recovery was observed in group PBS beginning at 6 hours of hypothermic incubation (27.6%). Group MSS significantly suppressed the release of CPK and LDH compared to group NSS at 24 hours (MSS, 246.7 and 440.2 mIU/flask; NSS, 369.7 and 821.3 mIU/flask, respectively). In contrast, groups PBS and KHB showed significantly increased CPK and LDH levels compared to group NSS after 12 hours (PBS, 388.6 and 721.4 mIU/flask; KHB, 340.5 and 540.5 mIU/flask; NSS, 91.5 and 222.7 mIU/flask, respectively). In conclusion, Hepes buffer has cytoprotective characteristics that may be suitable for long-term hypothermic preservation of immature myocardium compared to phosphate or bicarbonate buffer.

Clinico-pathological studies on a transitional type between extrahepatic biliary atresia and paucity of the interlobular bile ducts

Among the neonatal and infantile cases of obstructive jaundice seen at Niigata and Yamagata University Hospitals between 1976 and 1990, extrahepatic bile ducts were visualized in 19 cases by either preoperative endoscopic retrograde cholangiopancreaticography (ERCP) or intraoperative cholangiography. Neonatal hepatitis was diagnosed in 3 of these cases by clear images of the bile duct system extending from the common bile duct to the intrahepatic bile duct. In 7 cases, the common bile duct was able to be seen, while the common hepatic duct was only slightly visualized. Four of these 7 cases were consistent with paucity of the interlobular bile ducts (PILBD) based on hepatic histology, while the remaining 3 showed fibrosis, bile ductular proliferation, and many bile plugs in the bile ductuli of the portal areas, concurrent with histological changes in extrahepatic biliary atresia (EHBA), not PILBD. In 9 cases, only the common bile duct was visualized while the common hepatic duct was not seen, 7 of these 9 cases being consistent with type III-al EHBA. In 2 cases, neither fibrosis nor proliferation of the bile ductuli was observed in the portal areas, and portal areas without any bile ductuli were also seen, in accordance with findings for PILBD. Three cases which showed similar hepatic histological findings to EHBA despite the presence of patent extrahepatic bile ducts, and 2 cases which had obstructed extrahepatic bile ducts and hepatic histological findings similar to PILBD, were thought to be of a transitional type between EHBA and PILBD. Thus, it is postulated that the entire bile duct system covering hepatocytes to extrahepatic bile ducts is affected by a certain factor, but the expression of individual disease types may be dependent upon the location of the site most seriously affected.

Accelerated myocardial metabolic and functional recovery with terminal nicorandil-Mg cardioplegia in heart transplantation

SummaryCardiac reperfusion injury after heart transplantation or cardiopulmonary bypass has been difficult to control due to the variable degree of myocardial damage with respect to the length of ischemia and the complexity of the surgical procedure. Here, we evaluated the myocardial metabolic and functional recovery of hearts infused with a nicorandil vasodilator-magnesium (Mg) solution just prior to reperfusion (terminal cardioplegia). Donor hearts (20 dogs) were removed and immersed in a 4°C water bath containing 20 mEq/1 KCL-5% glucose for 6 hours, and then were transplanted to recipient dogs. Orthotopically transplanted dog hearts were either reperfused without any further treatment or received a terminal cardioplegic solution containing 8 mg/ 1 nicorandil, 30 mEq/1 Mg, and 50 g/1 glucose, which was infused at a pressure of 75 cm H2O for 2 minutes. During the reperfusion period, myocardial tissue PCO2 (t-PCO2) and calcium ion (t-Ca) were continuously monitored by an ISFET (ion-sensitive field effect transistor) sensor. Myocardial oxygen consumption and lactate flux were calculated/monitored at 5, 10, 20, and 40 minutes of reperfusion. Thereafter, myocardial function was evaluated at 45 minutes of reperfusion using LVSWI. Just after reperfusion, the treatment group (group B, n = 10) had a significantly greater coronary flow than the control group (Group A, n = 10, 35.0 ± 10.1; group B, 47.4 ± 8.5 ml/100 g/min, p < 0.025). Myocardial tissue PCO2 and calcium ion levels in group B were significantly decreased at 5 minutes of reperfusion (A: 110 ± 21 → 88 ± 16; B: 126 ± 24 mmHg → 44 ± 7 mmHg, t-PCO2, p < 0.001; A: 3.5 ± 0.7 → 3.2 ± 0.7; B: 2.7 ± 0.7 mM → 1.7 ± 0.6 mM, t-Ca, p < 0.001). Also, group B had better metabolic recovery, as evaluated by increased myocardial oxygen consumption and increased lactate flux. Thus, terminal nicorandil-Mg cardioplegia improved myocardial blood flow, which in turn markedly improved tissue acidosis, thereby reducing the extent of reperfusion injury.