Biomedical subjects

Y Kawashima

Publications and source records attributed to Y Kawashima.

At least 163 records · Page 9Linked to original sources

PubMed1996

Factors affecting rhythm after the maze procedure for atrial fibrillation.

BACKGROUND: The maze procedure failed to abolish atrial fibrillation (AF) in 14% of patients with underlying organic cardiac lesions. Identification of contributing risk factors will improve results either by treatment of such factors or by avoidance of high-risk patients. METHODS AND RESULTS: We analyzed 192 consecutive patients with AF undergoing three variations of the maze procedure performed simultaneously with correction of valvular diseases (n = 165), congenital anomalies (n = 19), isolated AF (n = 7), and ischemic disease (n = 1). Twenty-six preoperative factors and two postoperative cardiac size parameters were analyzed by multivariate analyses between patients with successfully ablated AF (n = 165) and those who remained in AF (n = 27) after the maze procedure. Among all factors, postoperative left atrial dimension was the most potent in predisposing patients to persistent AF. Duration of AF left atrial dimension, and cardiothoracic ratio were identified as preoperative risk factors, whereas modifications of the maze procedure and pathogenesis and location of underlying disease failed to have a significant prognostic impact on rhythm after surgery. Individual risk analysis using the three preoperative variables revealed that left atrial size reduction to normalize its dimension played a pivotal role in determining rhythm after the maze procedure. CONCLUSIONS: Results favor earlier performance of the procedure before these risk factors develop, after which omission of the procedure or extensive left atrial plication may be appropriate. This requires further study.

Adolescent↗

PubMed1996

Is use of aprotinin safe with deep hypothermic circulatory arrest in aortic surgery? Investigations on blood coagulation.

BACKGROUND: The perioperative blood coagulation and fibrinolysis system in patients who underwent aortic surgery under deep hypothermic circulatory arrest with or without aprotinin usage was investigated. METHODS AND RESULTS: Of 112 patients who underwent aortic surgery between December 1993 and April 1995, 60 had repair under deep hypothermic circulatory arrest. Thirty-nine patients had 2 million U aprotinin in pump priming and had no additional aprotinin. There were 20 patients with aortic dissections and 17 with atherosclerotic aneurysms. Twenty-two patients had left thoracotomy, and 17 had midsternotomy. Surgery consisted of replacement of the ascending aorta in 9 patients, total arch replacement in 11, distal arch replacement in 11, replacement of the descending aorta in 3, and replacement of thoracoabdominal aorta in 5. The control group was 21 patients who underwent operation under deep hypothermic circulatory arrest and retrograde cerebral perfusion but without aprotinin. Blood coagulation and fibrinolysis tests, consisting of activated clotting time, prothrombin time, activated partial thromboplastin time, fibrinogen, antithrombin III, plasminogen, alpha 2-plasmin inhibitor, thrombin-antithrombin complex, plasmin inhibitor complex, fibrin degenerative products, and D-dimer complex, were performed at various stages of surgery, before heparin administration, after heparin, 60 minutes and 120 minutes after beginning of the extracorporeal circulation, 1 hour after protamine administration, and 6 hours after protamine. Statistical analysis was performed with Student's t test, chi 2 test, and ANOVA. The amount of bleeding after perfusion was less in the aprotinin group, and bleeding during first 24 hours in the intensive care unit was less. Blood examination revealed that prothrombin time was higher after cessation of cardiopulmonary bypass in the aprotinin group. Thrombin-antithrombin III complex and alpha 2-plasmin inhibitor were higher during and after bypass in the aprotinin group. There was no difference in activated clotting time, activated partial thromboplastin time, fibrinogen, antithrombin III, plasminogen, plasmin inhibitor complex, fibrin degenerative products, and D-dimer complex. CONCLUSIONS: Clinical advantages of hemostatic effects of low-dose aprotinin and no apparent deleterious effects were demonstrated in patients who underwent aortic surgery under deep hypothermic circulatory arrest with retrograde cerebral perfusion. However, blood coagulation and fibrinolytic studies revealed subclinical hypercoagulation. Therefore, and adequate dose of heparin is required during deep hypothermic circulatory arrest.

Aged↗

PubMed1996

Binding properties of SA4503, a novel and selective sigma 1 receptor agonist.

The binding profiles of SA4503 (1-(3,4-dimethoxyphenethyl)-4-(3-phenylpropyl)piperazine dihydrochloride), a novel sigma receptor ligand, to sigma 1 and sigma 2 receptor subtypes in guinea pig and rat brain membranes were evaluated. SA4503 showed a high affinity for the sigma 1 receptor subtype labeled by (+)-[3H]pentazocine (IC50 = 17.4 +/- 1.9 nM), while it had about 100-fold less affinity for the sigma 2 receptor subtype labeled by [3H]1,3-di(2-tolyl)guanidine ([3H]DTG) in the presence of 200 nM (+)-pentazocine. SA4503 showed little affinity for 36 other receptors, ion channels and second messenger systems. The inhibition curves of SA4503 for (+)-[3H]pentazocine binding were shifted to the right in the presence of guanosine 5'-o-(3-thiotriphosphate) (GTP gamma S), as similar to those of (+)-3-(3-hydroxyphenyl)-N-(1-propyl)piperidine ((+)-3-PPP) and (+)-pentazocine, sigma 1 receptor agonists. SA4503 significantly increased the KD value, but did not affect the Bmax value for specific (+)-[3H]pentazocine binding. These results indicated that SA4503 is a potent and selective agonist for the sigma 1 receptor subtype in the brain. In addition, SA4503 inhibited specific (+)-[3H]pentazocine binding in a competitive manner.

Animals↗

PubMed1996

Effects of oral administration of erythritol on patients with diabetes.

Erythritol (20 g in solution) was administered orally in a single-dose to 5 patients with diabetes. Serum erythritol levels reached a peak 1 hr after administration and then declined rapidly. Total urinary excretion was 82.0 +/- 3.7% within 24 hr and 88.5 +/- 3.3% within 72 hr. Serum glucose and insulin levels remained unchanged until a meal was taken (3 hr after erythritol administration) and then increased. Free fatty acids and 3-hydroxybutyric acid levels increased after erythritol administration but dropped after ingestion of food. In a separate clinical trial, erythritol (20 g) was administered orally daily for 14 days to 11 patients with diabetes. Mean serum glucose and hemoglobin A1c levels decreased over the time period. Indices of renal function-blood urea nitrogen, creatinine, and beta 2-microglobulin-did not change significantly. The single dose study suggests that erythritol exerts no significant effects on the metabolism of diabetic patients. Two-week daily administration of erythritol had no adverse effect on blood glucose control.

Administration, Oral↗

PubMed1996

The effects of acute phencyclidine treatment on neuropeptide Y (NPY) neuronal system in the rat arcuate nucleus studied by immunocytochemistry and in situ hybridization.

Phencyclidine (PCP) is a dissociative drug and an antagonist of N-methyl-D-aspartate (NMDA) receptor. The effects of PCP treatment on neuropeptide Y (NPY) system in the arcuate nucleus of the rat hypothalamus were examined both by immunocytochemistry and in situ hybridization. In acute PCP-treated rats, the NPY-immunoreactive perikarya appeared in the arcuate nucleus but no perikarya were detected in controls, without colchicine pretreatment. The signals of NPY mRNA by in situ hybridization increased in the PCP-treated rats than those of controls. These results suggest that the NPY system in the arcuate nucleus might be partly controlled by glutamatergic neurons.

Animals↗

PubMed1996

Maze procedure and anomalous coronary artery repair.

A 60-year-old woman has anomalous origin of the left coronary artery from the pulmonary artery, mitral regurgitation with left ventricular dysfunction, and atrial fibrillation. We performed mitral valve annuloplasty, maze procedure, and intrapulmonary tunnel repair of anomalous origin of the left coronary artery. The patient regained normal sinus rhythm and showed improved left ventricular function and no mitral regurgitation.

Cardiac Surgical Procedures↗

PubMed1996

Rationale of the Cox maze procedure for atrial fibrillation during redo mitral valve operations.

OBJECTIVE: The frequency of reoperation for mitral valve diseases with chronic atrial fibrillation has increased steadily. This study examined the rationale for using the Cox maze operation for atrial fibrillation during redo mitral valve operations. METHODS: Between June 1992 and July 1995, we performed the maze procedure in 42 patients as a concomitant operation with redo mitral valve surgery (maze group). Associated procedures were tricuspid valve surgery in 27 patients and aortic valve surgery in 15 patients. The mean age at operation was 57.3 +/- 9.7 years, and the mean interval from the previous operation was 14.3 +/- 10.5 years. The mean follow-up period after the maze procedure was 25.5 +/- 10.8 months. Atrial fibrillation was present at the time of the previous operation in 29 patients (69%). RESULTS: Neither hospital death nor late death occurred. Sinus rhythm was regained in 28 patients (67%), and an atrial A-wave was detected in 21 patients (50%) by pulsed Doppler study. Patients in whom sinus rhythm was restored had a shorter history of atrial fibrillation (9.0 +/- 6.0 years vs 15.9 +/- 4.6 years, p = 0.0009), a larger f-wave on lead V1 of the electrocardiogram (0.18 +/- 0.10 mV vs 0.10 +/- 0.08 mV, p = 0.017), and a smaller cardiothoracic ratio (63% +/- 8% vs 67% +/- 5%, p = 0.049) than patients with persistent atrial fibrillation. During the same period, 54 patients underwent mitral valve reoperation without the maze procedure (control group). The aortic crossclamp and cardiopulmonary bypass times were slightly longer (p = 0.048 and p = 0.012) in the maze group (133 +/- 28 minutes and 221 +/- 43 minutes) than in the control group (126 +/- 65 minutes and 197 +/- 78 minutes). There was no significant difference in the amount of chest tube drainage or transfusion between the two groups (890 +/- 510 ml and 2120 +/- 1600 ml, respectively, in the maze group and 840 +/- 480 ml and 2140 +/- 1760 ml, respectively, in the control group). It was not necessary to reopen the chest for bleeding significantly more often in one group than in the other (14% in the maze group and 7% in the control group), and it was possible to operate without transfusion with the same frequency in the two groups (17% in the maze group and 20% in the control group). CONCLUSION: These results suggest that the maze procedure should be considered in selected patients who have a high possibility of regaining sinus rhythm during redo mitral valve operations.

Adult↗

PubMed1996

Unifocalization for pulmonary atresia with ventricular septal defect and major aortopulmonary collateral arteries.

To extend the indications for corrective operation in patients with pulmonary atresia, ventricular septal defect, and major aortopulmonary collateral arteries, surgical procedures were done to unify the blood sources for pulmonary perfusion. Since December 1985, 50 patients have undergone unifocalization at ages from 2 months to 26 years with a mean of 6 +/- 7 years. In total, 84 staged unifocalization procedures and 5 other palliative procedures were done in 49 patients. These included several operative procedures: simple ligation of major aortopulmonary collateral arteries in 8; pulmonary angioplasty in 29 including reconstruction of the pulmonary arterial tree by direct anastomosis or interposition between the central pulmonary arteries and the intrapulmonary arteries; construction of artificial central pulmonary arteries with use of a xenograft pericardial tube graft in 36 with no native central pulmonary arteries detected; and construction of supplemental central pulmonary arteries also with use of a pericardial tube graft in 10. The pericardial tube graft, if used, was anastomosed to the intrapulmonary arteries on one end and connected to a prosthetic tube on the other end so as to perfuse the reconstructed pulmonary arteries. The anastomosis was made inside the lung through the divided interlobar fissure. Five patients died after operation among those undergoing these 89 preparative operative procedures. Deaths were related either to bleeding caused by anticoagulation therapy administered to prevent thrombosis within the xenograft pericardial tube graft used or to progressive congestive heart failure as a result of an excessive amount of pulmonary blood flow. Twenty-six patients have undergone intracardiac repair after previous unifocalization. In 16 patients the artificial central pulmonary arteries surgically constructed were connected to each other and then an external conduit was placed. In another patient, intracardiac repair and unifocalization could be concomitantly achieved via a median sternotomy. The right ventricle to left ventricle systolic pressure ratio immediately after intracardiac repair in 27 patients ranged from 0.24 to 0.91 with a mean of 0.54 +/- 0.17. One patient (4%) died shortly after intracardiac repair because of thrombosis within the pulmonary arteries. Postoperative catheterization showed that pulmonary vascular resistance was correlated significantly with the number of pulmonary vascular segments functioning rather than with the condition of the central pulmonary arteries. We conclude that surgical unifocalization is a feasible procedure before subsequent intracardiac repair, even in patients with critically hypoplastic or absent central pulmonary arteries.

Adolescent↗

PubMed1996

Ten-year experience with the Carpentier-Edwards pericardial xenograft in the tricuspid position.

We reviewed the cases of 66 patients who underwent 67 tricuspid valve replacements with Carpentier-Edwards pericardial xenografts between April 1985 and January 1994. Average patient age at time of operation was 52 years (range 8 to 71 years). Concomitant mitral or aortic valve replacements were performed in 46 patients. There were 10 operative deaths and 6 late deaths. Actuarial survival at 9 years was 75.4% +/- 5.7%. Prosthetic valve endocarditis occurred twice in one patient. Reoperations for tricuspid regurgitation and for concomitant procedures (maze operation and repair for leak of the mitral prosthesis) were performed in two patients. In both cases, examination of the explanted prostheses showed that the tricuspid regurgitation was the result of nonstructural dysfunction caused by fibrous pannus formation on the cusps of the ventricular side. Among the survivors, 47 patients (92%) were in functional class I or II. Prosthetic valve function was studied by color Doppler echocardiography. Among 38 patients, tricuspid regurgitation more than grade 3/4 or transprosthetic gradient more than 5 mm Hg was found in 11. One patient had right heart failure and the others had no symptoms. In 10 years of experience with the Carpentier-Edwards pericardial xenograft, mortality and morbidity after tricuspid valve replacement were satisfactory. Echocardiographic examination revealed subclinical prosthetic dysfunction in 35% of patients who were followed up for longer than 5 years, however, and we believe that these patients should receive careful follow-up.

Adolescent↗

PubMed1996

Transient reperfusion with acidic solution affects postischemic functional recovery: studies in the isolated working rat heart.

This isolated working rat heart study was designed to investigate the effect of duration of reperfusion and degree of acidity of the reperfusate on myocardial protection. The experimental time course was as follows: 20 minutes of perfusion with the heart working, 3 minutes of infusion with the St. Thomas' Hospital cardioplegic solution followed by global ischemia for 33 minutes at 37 degrees C, and 20 minutes of Langendorff reperfusion followed by 20 minutes of working perfusion. During the initial 3 minutes of Langendorff reperfusion, the pH of the reperfusate was changed to 5.6, 6.8, and 7.5 by addition of sodium hydroxide into Krebs-Henseleit nonbicarbonate HEPES buffer. A respiratory acidic reperfusate was used for the initial 0.5, 1, 2, 3, 5, and 15 minutes during reperfusion. The results were as follows: (1) Reperfusion with a mildly acidic solution (i.e., pH 6.8) yielded better recovery than reperfusion with solutions having pH levels of 5.8 or 7.5. (2) Reperfusion for less than 3 minutes with a reperfusate having a pH level of 6.8 provided better recovery, although reperfusion for longer than 3 minutes exacerbated reperfusion injury. In conclusion, the effects of reperfusion with acidic solution were influenced by degree and duration with biphasic response characteristics.

Analysis of Variance↗

PubMed1996

Risks and benefits of combined maze procedure for atrial fibrillation associated with organic heart disease.

OBJECTIVES: This study sought to identify the risks and benefits of adding the maze procedure in patients with atrial fibrillation (AF) undergoing operation for underlying organic cardiac disorders. BACKGROUND: Persistent AF often leaves patients symptomatic even after otherwise successful cardiac surgery. METHODS: Fifty-one patients undergoing valvular operation and the maze procedure (n = 43) or repair of congenital anomalies (n = 8) combined with the maze procedure were compared with 51 patients (control group) matched for underlying diseases and procedures except for the maze operation. Each group, including 31 patients with a concomitant tricuspid annuloplasty and 12 undergoing reoperation, were similar in age, duration of arrhythmia, degree of cardiomegaly and New York Heart Association functional class. RESULTS: Patients undergoing the maze procedure had longer cardiopulmonary bypass time (213 vs. 144 min, p < 0.0001), longer cardiac arrest (134 vs. 93 min, p < 0.0001) and greater blood loss with longer respiratory care (39 vs. 18 h p = 0.021) and intensive care unit stay but no mortality. No significant differences were found in catecholamine or transfusion requirements immediately after operation. Sustained AF was much less frequent in the maze group (12% at 1 year) than the control group (86%, p < 0.0001), with an average follow-up period of 32 months (range 25 to 42). Atrial contraction was documented in 41 (80%) and 40 (78%) patients for right and left ventricular filling, respectively, after the maze procedure, resulting in a significantly smaller cardiac size and improved functional capacity. Medication was discontinued in seven patients in the maze group compared with two in the control group. CONCLUSIONS: Improved restoration of atrial rhythm and contraction with combined maze operation appeared to justify the increased operative time and complexity and postoperative care.

Atrial Fibrillation↗

PubMed1996

Results of unifocalization for pulmonary atresia, ventricular septal defect and major aortopulmonary collateral arteries: patency of pulmonary vascular segments.

Unifocalization, a surgical technique to unifocalize the pulmonary blood supply in patients with pulmonary atresia, ventricular septal defect and major aortopulmonary collateral arteries, is a useful preparative operation to extend the indication for corrective surgery. The preoperative and postoperative pulmonary angiograms of 51 patients (aged 3 months-26 years at first unifocalization, 29 males, 22 females), who underwent a total of 96 unifocalizations from December 1985 to July 1994, were studied to assess the effectiveness of each procedure of unifocalization. The procedures of unifocalization were ligation (9), angioplasty (6), direct anastomosis (25), bridging (6), additional central pulmonary artery creation (9), central pulmonary artery creation (36) and thrombectomy (5). Altogether 125 anastomoses were made, and the patency of 101 (80.2%) anastomoses was confirmed, 24 (19.2%) were shown to be occluded. The patency rate of the anastomoses between xenograft rolls and intrapulmonary arteries was 79.5% (70/88), while that between native central pulmonary arteries and intrapulmonary arteries was 83.8% (31/37; N. S.). The patency rate of the anastomoses involving intrahilar arteries was 88.0% (44/50), while that for the group involving extrahilar arteries only was 71.9% (46/64; P < 0.05). It is concluded that 1) unifocalization with the reconstruction of central pulmonary arteries using a pericardial roll is a useful method for patients with absent or hypoplastic central pulmonary arteries, 2) it is preferable to divide the fissures of lung in anastomosing pulmonary arteries of arborization abnormalities.

Adolescent↗

PubMed1996

Surgical anatomy of the coronary circulation in hearts with discordant atrioventricular connections.

We examined the arrangement of the coronary arterial and cardiac venous systems in 46 specimens with discordant atrioventricular connections so as to identify any structural abnormalities and to consider their surgical implications in terms of anatomical biventricular repair. Grossly abnormal arterial courses were seen in 11 hearts (24%). A substantial branch supplying the morphologically right ventricular outflow tract, which could restrict a ventriculotomy, was found in 61% of cases. The coronary sinus received all the morphologically right ventricular veins, as well as the posterior interventricular vein, in 40 hearts, this pattern being in contrast to the pattern in the normal heart. The morphologically left ventricular and anterior interventricular veins, all of which drain via the coronary sinus in the normal heart, were frequently connected independently to the morphologically right atrium in the specimens with discordant connections, the drainage occurring through the spaces between the pectinate muscles. These direct drainages are at risk of potential damage either by extensive intra-atrial maneuvers or by postoperative intraatrial thrombosis. It is predicted, therefore, that surgical results can be improved still further when account is taken of this vascular anatomy of the heart itself.

Cadaver↗

PubMed1996

Predictive factors for postoperative cerebral complications in patients with thoracic aortic aneurysm.

OBJECTIVE: Perioperative factors affecting the outcomes of postoperative brain function in patients with thoracic aortic aneurysm were demonstrated. PATIENTS AND METHODS: From December 1977 to September 1994, 745 patients with thoracic aortic aneurysm underwent 846 operations. The mean age at surgery was 57.1 +/- 14.2 years old. Four hundred seventy-four patients had true aneurysm and 372 had aortic dissection. Two hundred forty-four patients underwent repair in the ascending aorta, 189 arch repair, 242 repair in the descending aorta. 79 replacement of the thoracoabdominal aorta, and 92 extra-anatomical bypass or thrombo-exclusion of the aorta. Conventional cardiopulmonary bypass was used in 297 patients, partial cardiopulmonary bypass through femoral access in 167, selective cerebral perfusion in 253, deep hypothermic circulatory arrest and retrograde cerebral perfusion in 50, temporary shunt in 29, and no circulatory support was applied in 50. Postoperative cerebral complications were divided into permanent cerebral dysfunction. RESULTS: The early mortality rate was 15.5% (131 patients). Incremental risk factors for hospital mortality were non-preexisting cardiac lesions, ruptured aneurysm, postoperative cerebral complications, sepsis, bleeding, low output syndrome and renal failure. Cerebral complications occurred in 81 patients (9.6%), involving 47 permanent and 34 transient sequelae. The early mortality rate in patients with postoperative brain damage was 42.0%. The etiologies of the brain damage diagnosed by computed tomography were embolism in 41 patients, cerebral hypoperfusion in 16 and unknown in 24. Incremental risk factors for postoperative cerebral complications were: operation early in the series advanced age at surgery, preoperative renal failure, aortic arch lesions, atherosclerotic aneurysm, aortic arch procedures and clamping of the aortic arch. CONCLUSIONS: Although there was an increased incidence of advanced age and complex lesions in patients with aortic aneurysm, an improvement in surgical results has recently been achieved using advanced diagnostic and surgical techniques.

Adult↗

PubMed1996

Surgery for aortic dissection with intimal tear in the transverse aortic arch.

OBJECTIVES: This study reports surgical experience of 72 cases of aortic dissection with intimal tear in the transverse aortic arch. METHODS: Of 325 patients with aortic dissection, 72 (22.2%) had a tear in the arch, including 27 with acute dissection and 45 with chronic dissection. Mean age at surgery was 60.8 +/- 14.1 years. The dissection was localized from the ascending aorta to the arch in 30 patients and extensive from the ascending aorta to the descending aorta in 42. Surgeries consisted of total arch replacement in 50 patients, hemiarch replacement in 20, and extra-anatomical bypass in 1. In the initial series, cardiopulmonary bypass for brain protection during arch procedures was selective cerebral perfusion (61 patients), but since July 1993 deep hypothermic circulatory arrest with retrograde cerebral perfusion was exclusively utilized (8 patients). RESULTS: Hospital mortality was 9.7%, 11.1% of the patients who had acute dissection and 8.8% with chronic dissection. There has been no mortality since February 1993. The mean follow-up period was 51 +/- 37 months, and there were 3 late deaths. The 5 and 10 year survival rate was 85.3 +/- 4.8 in all patients, 84.3 +/- 8.9% with acute dissection, and 85.5 +/- 5.7% with chronic dissection. The 5 and 10 year survival was 79.8 +/- 7.1 with extensive dissection, and 93.5 +/- 6.5% with localized dissection. During follow-up, 6 patients underwent subsequent aortic surgeries. The freedom from reoperation at 5 years and at 10 years was 91.4 +/- 4.8% and 65.6 +/- 14.4%, respectively. In patients with acute dissection it was 92.3 +/- 7.4% and 61.5 +/- 25.6% at 5 years and 10 years, while with chronic dissection it was 87.0 +/- 7.0% and 44.0 +/- 17.3% at 5 years and 10 years, respectively (n.s.). The freedom from subsequent reoperation for the aorta in all patients was 91.4 +/- 4.8% at 5 years and 10 years was 65.6 +/- 14.4%. With acute dissection it was 92.3 +/- 7.4% at 5 years and 61.5 +/- 25.6% at 10 years, while that with chronic dissection it was 91.3 +/- 5.9% and 65.7 +/- 16.8% at 5 years and 10 years respectively (n.s.). The freedom from all reoperations with extensive dissection at 5 years and 10 years was 86.6% +/- 7.2% and 34.2 +/- 17.3%, respectively, moreover, the freedom from reoperations with localized dissection at 5 and at 10 years was 90.0 +/- 9.5% (n.s.). However, the freedom from subsequent aorta reoperation with extensive dissection at 5 years and 10 years was 86.6 +/- 7.2% and 56.0 +/- 16.0%, respectively, while with localized dissection it was 100% at 10 years (P < 0.01). CONCLUSION: Early and late surgical result for arch dissection was satisfactory with a surgical principle of resecting the aortic segment that contains the initial intimal tear and graft replacement.

Acute Disease↗

PubMed1996

Surgical stratification of patients with atrial fibrillation secondary to organic cardiac lesions.

BACKGROUND: While the maze procedure does not always eliminate atrial fibrillation (AF) secondary to organic cardiac lesions, concomitant performance of the procedure is associated with increased surgical complexity and potential risks. METHODS: To stratify the surgical approach for patients with AF secondary to underlying cardiac lesions, we analyzed 24 preoperative and perioperative variables in 115 consecutive patients with AF undergoing a modified maze procedure combined with valvular intervention (101), repair of congenital anomalies (13) and coronary revascularization (1). RESULTS: Patients who remained in AF (18) compared to patients with restored atrial rhythm (97), had a higher incidence of giant left atrium (56% vs 10%, P < 0.0001), larger cardiothoracic ratio (70 +/- 13 vs 62 +/- 8%, P = 0.001) and left atrial dimension (64 +/- 12 vs 55 +/- 12 mm, P = 0.004), a longer history of AF (13.7 +/- 6.8 vs 8.3 +/- 6.9 years, P = 0.003) and lower f-wave voltage (0.10 vs 0.15 mV, P = 0.004). Multivariate logistic regression analysis of 24 preoperative and perioperative variables identified the presence of giant left atrium, cardiothoracic ratio and age at operation as the significant risk factors predisposing patients to persistent postoperative AF. Retrospective estimation identified 73 (63.5%) patients with a high probability of atrial defibrillation (97.3%) and 42 (36.5%) patients with a high risk of failure (38.1%). Regardless of the preoperative risk analysis or the performance of left atrial plication, every patient with a postoperative left atrial dimension less than 40 mm or cardiothoracic ratio below 55% was successfully defibrillated. CONCLUSION: The results suggest performing the maze procedure before "risk factors" develop for patients with predicted maze-amenable AF. While omitting the maze procedure may be prudent for patients with suspected maze-refractory AF, the simultaneous reduction of left atrial size may offset the increased risk from preoperative size factors. A prospective study seems warranted to examine the effects of left atrial plication on postoperative rhythm.

Adult↗

PubMed1996

Right lung transplantation followed by left pneumonectomy in the rat.

OBJECTIVE: To develop a rodent lung transplant model which depends on graft function for survival, total microsutureless lung transplantation was carried out and followed by contralateral native pneumonectomy in the rat. METHODS: Total non-microsuture right lung transplantation was undertaken using a cuff technique with anastomotic areas twice as big as those for the left lung transplantation. Inbred rats received either right (n = 10) or left lung isograft (n = 10) with non-microsuture techniques and underwent contralateral native pneumonectomy 2 weeks later to test the function of the grafted lung. RESULTS: While none of the left lung recipients could be disconnected from the respirator after right pneumonectomy, eight of ten right lung recipients tolerated left pneumonectomy, increased body weight and regained exercise capacity (oxygen uptake 49 +/- 4 ml/kg per min) comparable to that of control rats undergoing right hilar stripping and left pneumonectomy. CONCLUSIONS: The results suggest that the grafted right lung, but not the left lung, allows survival, growth and exercise of the recipient. Right lung transplantation followed by native left pneumonectomy may serve as a physiologic model of lung transplantation in the rat.

Animals↗

PubMed1996

Enteral absorption of insulin in rats from mucoadhesive chitosan-coated liposomes.

PURPOSE: The mucoadhesiveness of polymer-coated liposomes was evaluated to develop a novel drug carrier system for oral administration of poorly absorbed drugs such as peptide drugs. METHODS: Multilamellar liposomes consisting of dipalmitoylphosphati-dylcholine (DPPC)and dicetyl phosphate (DCP) (DPPC: DCP = 8:2 in molar ratio) were coated with chitosan (CS), polyvinyl alcohol having a long alkyl chain (PVA-R) and poly (acrylic acid) bearing a cholesteryl group. The adhesiveness of the resultant polymer-coated liposomes to the rat intestine was measured in vitro by a particle counting method with a Coulter counter. The CS-coated liposomes containing insulin were administered to normal rats and the blood glucose level was monitored. RESULTS: The existence of polymer layers on the surface of liposomes was confirmed by measuring the zeta potential of liposomes. The CS-coated liposomes showed the highest mucoadhesiveness and the degree of adhesion was dependent on the amount of CS on the surface of the liposomes. The blood glucose level of rats was found to be significantly decreased after administration of the CS-coated liposomes containing insulin. The lowered glucose level was maintained for more than 12h after administration of the liposomal insulin, which suggested mucoadhesion of the CS-coated liposomes in the intestinal tract of the rats.

1,2-Dipalmitoylphosphatidylcholine↗