Mitsuhiro Hachida

The role of leukocyte depletion in reducing injury to myocardium and lung during cardiopulmonary bypass.

Activated leukocytes and oxygen free radicals have been implicated in the pathogenesis of heart and lung injury after reperfusion and during cardiopulmonary bypass. This study was designed to determine whether leukocyte depletion prevents injury to the heart and lung during cardiopulmonary bypass. Twenty-eight open heart surgeries were performed in this study. In Group F, leukocyte depletion was performed with an LG-6 arterial line filter after aortic declamp (n = 14). Leukocyte depletion was not performed during cardiopulmonary bypass in Group C (n = 14). Thereafter, cardiac and lung function were assessed in the 24 hr after reperfusion. The total catecholamine dose used for 24 hr after reperfusion (r) was 61.9 +/- 13.4 in Group C and 43.9 +/- 19.2 in Group F (p < 0.05). CK-MB at 3 and 6 hr after reperfusion was 65.9 +/- 13.5 and 64.8 +/- 15.8 in Group C and 45 +/- 11.8 and 38 +/- 10.8 in Group F, respectively (p < 0.05). The pulmonary index after reperfusion at 3 and 6 hr was 1.7 +/- 0.5 and 1.3 +/- 0.4 in Group C and 0.7 +/- 0.3 and 0.6 +/- 0.4 in Group F, respectively (p < 0.05). There was significantly better preserved lung function in Group F. In conclusion, leukocyte depletion was significantly effective in preserving heart and lung function during cardiopulmonary bypass.

Current strategy of temporary circulatory support for severe cardiac failure after operation

BACKGROUND After open heart operations about 1% of patients still need temporary circulatory support for severe cardiac failure, and over half of those patients die during or after the support. This study assessed the efficacy of the current strategy of circulatory support. METHODS We assessed clinical outcome of 64 consecutive patients (1.5% of pump cases) who had temporary circulatory support associated with perioperative variables. The results were analyzed by logistic regression analysis. RESULTS The weaning and discharge rates were 50.0% and 26.7% with venoarterial bypass, 76.2% and 57.1% with biventricular bypass, 87.5% and 37.5% with isolated left ventricular bypass, and 60.0% and 40.0% with pulsatile left ventricular assistance, respectively. Logistic regression analysis identified presupport cardiogenic shock (odds ratio, 9.922) and support type (14.684) as factors significantly associated with nonweaning from the temporary support, and cardiogenic shock (28.268), support duration (2.948), and support type (14.184) as factors significantly associated with mortality during or after the circulatory support. CONCLUSIONS The current strategy of temporary circulatory support improved clinical outcome of patients with severe cardiac failure. Early application of circulatory support before profound cardiogenic shock and proper selection of the support type might be key factors for successful circulatory support postoperatively after operation.

Retrograde Cerebral Perfusion with Hypothermic Blood Provides Efficient Protection of the Brain: A Neuropathological Study

Retrograde cerebral perfusion is a method that is recently being used for protection of the brain during operations on the aortic arch. This method is useful but is said to provide a limited time for protecting the brain. We designed an experiment in dogs to investigate neuropathologically the effect of protecting the brain for 120 minutes under: (1) circulatory arrest (CA); (2) retrograde cerebral perfusion with moderately cooled blood (RCPMC); and (3) retrograde cerebral perfusion with deeply cooled blood (RCPDC). We calculated the number of the abnormal cells of 400 hippocampal neurons per dog light microscopically. The number was 199 ± 23 (mean ± 1 SD) in the CA group, 149 ± 50 in the RCPMC group, and 72 ± 33 in the RCPDC group. The difference between the CA group and the RCPMC group was not statistically significant (p < 0.05), but there was a significant difference between the RCPMC and RCPDC groups (p < 0.05). The degree of cerebral protection provided by retrograde cerebral perfusion for 120 minutes is not sufficient when using moderately cooled blood. If we use deeply cooled blood at a temperature of about 10°C, we should obtain a sufficient degree of protection of the brain.

Clinical Assessment of Prolonged Myocardial Preservation for Patients With a Severely Dilated Heart

BACKGROUND The purpose of this study was to compare the myocardial protective effect of histidine-tryptophan-potassium and glucose-insulin-potassium cardioplegic solutions in patients with a dilated heart (left ventricular diastolic diameter > 55 mm, left ventricular systolic diameter > 45 mm) associated with prolonged cross-clamp time (longer than 200 minutes). METHODS We selected 20 patients with dilated hearts due to severe aortic regurgitation. Glucose-insulin-potassium cardioplegia was used in 11 patients and histidine-tryptophan-potassium cardioplegia was used in 9 patients. RESULTS After operation, the cardiac index was significantly increased in the histidine-tryptophan-potassium group (p < 0.05). Postoperative percent fractional shortening was 13.4% +/- 3.1% in the glucose-insulin-potassium group and 23.6% +/- 2.6% in the histidine-tryptophan-potassium group (p < 0.05). Creatine kinase levels were significantly lower in the histidine-tryptophan-potassium group than that in the glucose-insulin-potassium group (p < 0.05). The incidence of ventricular arrhythmia (higher than Lowns grade 2) was lower in the histidine-tryptophan-potassium group. CONCLUSIONS These data support the superiority of the histidine-tryptophan-potassium method over the glucose-insulin-potassium method for protection of the dilated heart during prolonged ischemia in open heart operations.

Limit of warm ischemia time before cryopreservation in rat tracheal isografts

BACKGROUND The viability of cadaveric tracheal grafts undergoing cryopreservation is still unclear. We evaluated the limit of warm ischemia time before cryopreservation in rat tracheal isografts. METHODS Each isograft was harvested from donor rats 0 to 48 hours (0, 6, 12, 18, 24, and 48 hours) after circulatory arrest, immersed in the preservative solution, and stored in a deep freezer until reaching -80 degrees C and then was kept in liquid nitrogen for 3 months. Heterotopic transplantation into the omentum was performed after the isografts were thawed. Graft morphology 3 months after transplantation was assessed. RESULTS The stepwise increase of warm ischemia time significantly reduced graft survival. A prolonged period of warm ischemia had a degenerative effect on both the epithelium and cartilage. The morphology of the epithelium and cartilage in isografts undergoing warm ischemia for less than 18 hours was better preserved, whereas it deteriorated in isografts undergoing warm ischemia for more than 24 hours. CONCLUSIONS We thus conclude that the permissible period of warm ischemia before 3-month cryopreservation to maintain tracheal isograft viability is 18 hours in rats.

Percutaneous transaortic closure of postinfarctional ventricular septal rupture

We report a case of successful closure of a postinfarctional ventricular septal defect by means of the transaortic approach with a balloon catheter. This method brought about substantial improvement in cardiopulmonary function before an elective operation and made it possible to successfully perform the operation on the patient, an 81-year-old woman, on the 22nd day of admission.

Effectiveness of ischemic preconditioning on long-term myocardial preservation.

BACKGROUND This study was designed to assess whether the protective effect of ischemic preconditioning can be adapted for myocardium undergoing 6 hr of ischemia. METHODS Eighteen isolated rat hearts were perfused with oxygen-bicarbonated Krebs-Henseleit buffer in the Langendorff mode for 35 min (group A, controls) or perfused in the Langendorff apparatus for 20 min, followed by 5 min of global normothermic ischemia and 10 min of buffer perfusion (group B, preconditioning) or followed by two cycles of 2.5 min of global normothermic ischemia plus 5 min of buffer perfusion (group C, preconditioning). The hearts were then arrested and preserved for 6 hr with Bretschneiders histidine-tryptophan-potassium cardioplegic solution at 4 degrees C, followed by 30 min of reperfusion. Recovery of cardiac function, postischemic enzyme leakage, and intracellular calcium concentration were compared. RESULTS After 6 hr of ischemia, the hearts that underwent preconditioning in groups B and C showed better recovery of left ventricular developed pressure (P<0.05), a lower end-diastolic pressure level (P<0.05), less leakage of creatine kinase, and a lower intracellular calcium concentration than those in group A. There were no statistical differences in the rate of recovery of coronary flow. CONCLUSIONS Our study demonstrated that ischemic preconditioning improves myocardial functional recovery after 6 hr of hypothermic preservation in the isolated rat heart. Preconditioning might be useful for preserving the heart against long-term ischemia/reperfusion injury.

Association between the degree of platelet-derived growth factor-A chain mRNA expression and coronary arteriosclerosis in the transplanted heart

SummaryAlthough intimal and medial proliferation of smooth muscle cells is recognized as one of the key mechanisms in the development of graft coronary arteriosclerosis, the role of platelet-derived growth factor (PDGF) in this process is still uncertain, because of the undetermined pathogenesis of graft coronary arteriosclerosis (GCA). In the present study, the correlation between the extent of GCA and the degree of PDGF-A chain expression in cardiac grafts was investigated in 21 rats with GCA of varying extent. Lewis rats underwent heterotopic heart transplantation from Wistar King donors and were treated with cyclosporine A (10mg/kg/day) (n=7), 15-deoxyspergualin (5 mg/kg/day) (n=7), orMultiglycosidorum tripterygii (MT) (30 mg/kg/day) (n=7). Histological evaluations of coronary arteriosclerosis, as well as Northern blot analysis of graft PDGF-A chain expression were made, 60 days after transplantation. Graft coronary arteriosclerosis of varying extent was observed among the 21 transplanted hearts. Significant correlations were found between the PDGF-A chain mRNA expression of cardiac allograft and the grade of arterial intimal thickening (Spearman’sr=0.76,P<0.005) as well as the incidence of diseased vessels (r=0.82,P<0.001). The PDGF-A chain mRNA expression of the cardiac allograft is associated with the extent of GCA, indicating that PDGF-A plays an important role in the development of GCA.

Regional cardiac sympathetic reinnervation in transplanted human hearts detected by123I-MIBG SPECT imaging

The purpose of this study was to assess the regional cardiac sympathetic reinnervation late (≥1 year) after heart transplantation (HTX) by means of123I-MIBG (MIBG) scintigraphy. Eight patients with a pretransplantation diagnosis of idiopathic dilated cardiomyopathy underwent MIBG scintigraphy more than one year after HTX. The presence or absence of regional MIBG uptake was evaluated in each SPECT image, and global MIBG uptake was semi-quantitatively assessed by the heart to mediastinum ratio (H/M). Five of 8 patients had visible MIBG uptake in both planar and SPECT images (PU group), whereas 3 of 8 patients had no uptake, 2 of them after a period of 2 years, and one of them as long as 5 years after HTX, respectively (NU group). Positive regional MIBG uptake involved the basal anterior region in all 5 patients, the basal septal region in 4 patients, the basal lateral region in 3 patients and the basal posterior region in 1 patient. The H/M value was 1.24±0.10 in the PU group and 1.09±0.03 in the NU group. In conclusion, MIBG SPECT can detect regional sympathetic reinnervation, indicating that basal septal and lateral regions next to the basal anterior are more likely to be reinnervated, but reinnervation is much less likely to occur in the midventricular and apical regions.

Inhibitory effect of Multiglycosidorum tripterygii on coronary arteriosclerosis after heart transplantation

BACKGROUND Graft coronary arteriosclerosis (GCA) is the major limiting factor for long-term survival after heart transplantation. In this study, we investigated the effect of Multiglycosidorum tripterygii (MT) on GCA and platelet-derived growth factor A (PDGF-A) mRNA expression of transplanted hearts. METHODS Two groups of Lewis rats (n=7/group) underwent heterotopic heart transplantation from Wistar-King donors and were treated with either cyclosporine (CsA;10 mg/kg/day) or MT (30 mg/kg/ day). Histological evaluations of rejection and coronary arteriosclerosis, as well as Northern blot analysis on graft PDGF-A mRNA expression were made 60 days after transplantation. RESULTS Morphometric results indicated no significant difference in rejection between the CsA- and MT-treated groups. However, the extent of GCA in the MT-treated group was significantly less than that seen in the CsA-treated group (P<0.01). The expression of PDGF-A mRNA of cardiac allograft was also significantly suppressed in the MT-treated group when compared with the CsA-treated group (P<0.01). CONCLUSION MT is superior to CsA in preventing graft coronary arteriosclerosis, and this efficacy is probably associated with the depressed expression of graft PDGF-A mRNA in the MT-treated group.