Hiroshi Izumoto

Predictors of sinus rhythm restoration after cox maze procedure concomitant with other cardiac operations

BACKGROUND There have been sporadic cases of persistent atrial fibrillation and sick sinus syndrome after the maze procedure. The purpose of this study was to identify the predictors of sinus rhythm restoration after operation. METHODS Between March 1993 and June 1995, we evaluated retrospectively 96 consecutive patients who underwent the maze procedure (maze III) in combination with another type of cardiac operation. Four patients who died and 6 patients who required permanent pacemaker implantation because of sick sinus syndrome were excluded. Ambulatory electrocardiographic monitoring was evaluated 1 year after operation. Multiple logistic regression analysis was applied to identify the predictors of sinus rhythm restoration. RESULTS The final population comprised 86 patients (mean age, 59.8 years; 67 patients with mitral valve disease). Overall, sinus rhythm was restored in 68 of 86 patients (79.1%). The magnitude of the atrial fibrillatory wave positively predicted postoperative sinus rhythm restoration. Conversely, left atrial diameter was inversely related to postoperative sinus rhythm restoration. The odds ratio of having both a fine atrial fibrillatory wave (< 1.0 mm) and enlarged left atrial diameter (> or = 65 mm) for patients with sinus rhythm restoration was 0.04 (95% confidence interval, 0.01 to 0.28). CONCLUSIONS Atrial fibrillatory wave and left atrial diameter were independent predictors of sinus rhythm restoration after the maze procedure in patients with chronic atrial fibrillation and organic heart disease.

Operative results after the Cox/maze procedure combined with a mitral valve operation

BACKGROUND There have been few reports on postoperative morbidity and mortality analyses after concomitant mitral valve operation and the Cox/maze procedure. METHODS Between April 1993 and August 1995, 87 consecutive patients with chronic atrial fibrillation underwent a mitral valve operation and concomitant Cox/maze procedure at Iwate Medical University. The patients were divided into the replacement group (n = 31) and repair group (n = 56) according to the method of mitral valve replacement. Our initial experience with the combined operative procedures is presented along with the operative mortality and morbidity rates. Univariate analysis on preoperative and intraoperative variables affecting early mortality and morbidity is carried out retrospectively. RESULTS Total cardiopulmonary bypass time in all patients was 177.2 +/- 70.1 minutes. Total aortic cross-clamp time was 121.7 +/- 30.8 minutes. Total intensive care unit stay was 5.3 +/- 7.9 days. The average intubation period was 55.5 +/- 187.6 hours. The intensive care unit stay and the intubation period of the replacement group were longer than those of the repair group. There were four operative deaths among the 87 patients (4.6%). All repair group patients survived operation, whereas 4 replacement group patients died after operation. In all patients, the New York Heart Association functional class was higher (p = 0.028) in those who died than in those who survived. The overall restoration rate from atrial fibrillation was 79.5% (66 of 83 survivors). Seventeen patients (20.5%) had persistent atrial fibrillation postoperatively. Sick sinus syndrome occurred in 7 patients (8.4%). In the repair group, the restoration rate was 76.8%, whereas in the replacement group it was 85.2% for the survivors. CONCLUSIONS The Cox/maze procedure can be combined with a mitral valve operation with acceptably low operative risk. Analysis of risk factors of early mortality revealed that the type of mitral valve operation (replacement versus repair) and higher preoperative New York Heart Association functional class were associated with mortality. Long-term results from this combined procedure should be clearly demonstrated before its universal acceptance.

Medium-term results after the modified Cox/Maze procedure combined with other cardiac surgery

OBJECTIVE Long-term results after the modified Cox/Maze III procedure combined with other cardiac procedure for the treatment of organic heart disease and chronic atrial fibrillation (AF) has not been clarified. This report describes our medium-term results after such operation. METHODS Between March 1993 and August 1995, 104 consecutive patients with chronic AF underwent the modified Cox/Maze III procedure combined with other cardiac procedure. There were 100 long-term survivors. There were 45 men and 55 women, with ages ranging from 21 to 77 years (mean 59.7). Patients were followed up and changes in rhythm, need for pacemaker implantation, and the incidence of CNS (central nervous system) complications were retrospectively studied. RESULTS The follow-up was complete in 103 patients and 99 long-term survivors (99%). The mean follow-up period was 44.6 +/- 1.1 months. In the immediate postoperative period, 73 patients regained sinus rhythm (SR group), 21 patients were in AF (AF group), and six patients underwent pacemaker implantation because of sick sinus syndrome (SSS). During the follow-up period, eight patients died. One- and 5-year survival rates (Kaplan-Meier) after surgery was 95.1 +/- 2.3 and 87.8 +/- 3.4% for the entire group. Preoperative NYHA class was 2.5 +/- 0.7 and medium-term NYHA class was 1.5 +/- 0.5. (P < 0.001) Changes in rhythm for the SR group were followed. Fifty-two patients of the SR group stayed in SR (72%), 16 patients converted back to AF (22%), and four patients had newly-developed SSS (6%) at follow-up period. Probability in SR maintenance for SR group at 1 year was 88.8 +/- 3.7% and at 5 years was 64.8 +/- 7.5%. Five patients experienced the CNS complication during the follow-up period. Two of the AF group and two of the SR group patients developed cerebral/cerebellar infarction. One of the SR group patients experienced small cerebral bleeding. CONCLUSIONS The medium-term results after the modified Cox/Maze III procedure concomitant with other cardiac procedure are good with improved functional status and good survival rate. However, there seems to be gradual but constant attrition in the rate of SR maintenance in SR group.

Expression and localization of tumour necrosis factor-α and its converting enzyme in human abdominal aortic aneurysm

Abdominal aortic aneurysm (AAA) is characterized by chronic aortic wall inflammation and loss of matrix components. Proinflammatory cytokines such as tumour necrosis factor-α (TNF-α )a re thought to be involved in this inflammatory process and, therefore, to play an important role in the pathogenesis of human AAA. TNF-α-converting enzyme (TACE) has recently been purified and cloned as a disintegrin and metalloproteinase that converts TNF-α precursor into its mature form. The aim of the present study was to determine whether TNF-α and TACE were expressed and localized in aortic tissues in human AAA. Infrarenal aortic tissues were obtained from AAA patients (n = 19) undergoing elective aneurysm reconstruction and from autopsy cases without cardiovascular disorders as normal controls (n = 5). Internal thoracic artery samples were also obtained from patients with coronary artery disease undergoing coronary artery bypass grafting to represent biopsied conduit vessels (n = 5). The AAA specimens were taken from the mid-portion of the aneurysm and from the longitudinal transition zone between the non-dilated aorta and the proximal aspect of the aneurysm. TNF-α and TACE mRNA levels were determined by realtime quantitative reverse transcriptase–PCR. Expression levels of both TNF-α mRNA and TACE mRNA were significantly greater in the transition zone than in the mid-portion (both P < 0.05). Expression levels of both forms of mRNA were significantly higher in AAA samples than in control aortas or atherosclerotic arteries. There was a significant correlation between the expression of TNF-α mRNA with that of TACE mRNA in AAA (r = 0.54, P < 0.005). Immunostaining was positive for both TNF-α and TACE in CD68-positive macrophages in the media and adventitia obtained from the transition zone in AAA, whereas neither TNF-α nor TACE was expressed in control vessels. In conclusion, the concomitant activation and localization of TNF-α and TACE in the media and adventitia of the transition zone in human AAA underlines the importance of this system in the pathogenesis of this disorder.

Successful utilization of the median sternotomy approach in the management of descending necrotizing mediastinitis: Report of a case

We describe herein the case of a patient in whom a median sternotomy was successfully employed for mediastinal drainage in the treatment of descending necrotizing mediastinitis (DNM). Although most reports describe cervical or thoracotomy approaches, our experience strongly suggests that median sternotomy is a satisfactory alternative approach for treatment of this disease.

Coagulopathy associated with residual dissection after surgical treatment of type A aortic dissection

PURPOSE This study was performed to evaluate the effects of a residual dissection on coagulation, fibrinolysis, and platelet function after surgical treatment of acute type A aortic dissection. METHODS Between 1987 and 1995, 48 consecutive patients underwent emergency surgery for acute type A aortic dissection. Thirty-five of 41 survivors were followed-up for periods ranging from 6 to 112 months (median, 30.3 months). These survivors were classified into three groups by computed tomographic scanning and angiography. Fifteen patients had no residual dissection (group I). Of the 20 patients who had residual dissection, nine had an enlarged aorta greater than 45 mm in maximal diameter (group II), and 11 had an aorta less than 45 mm in maximal diameter (group III). For all patients, blood samples were collected for coagulation, fibrinolysis, and platelet function studies on the same day that the computed tomographic scanning had been performed. RESULTS beta-thromboglobulin, thrombin-antithrombin III complex, D-dimer, and alpha 2 plasmin inhibitor-plasmin complex concentrations were significantly higher in group II than in the other two groups. Strong correlations between the maximal diameter of the dissected aorta and beta-thromboglobulin, thrombin-antithrombin III complex, D-dimer, and plasmin inhibitor-plasmin complex concentrations were evident. In contrast, correlations between the length of the dissected aorta and coagulation/fibrinolysis measurements were weak. CONCLUSIONS Our findings suggest that the coagulopathy worsened in proportion to the degree of dilatation of the dissected aorta.

Electrocardiographic nature of restored sinus rhythm after Cox maze procedure in patients with chronic atrial fibrillation who also had other cardiac surgery.

OBJECTIVE: To characterise heart rate variability and high frequency components of restored sinus rhythm after the maze procedure. The maze procedure for chronic atrial fibrillation may prevent thrombotic events and improve the quality of life. However, the electrocardiographic nature of restored sinus rhythm after the maze procedure has not been fully elucidated. PATIENTS AND METHODS: Between March 1993 and August 1995, 104 consecutive patients undergoing the maze procedure in combination with other cardiac surgery were studied. There were 100 long-term survivors (78 with mitral valve disease, 9 with aortic valve disease, 8 with congenital heart disease, and 5 others). Twenty age-matched patients with mitral valve disease who were in normal sinus rhythm preoperatively were enrolled as a control group. 30 days after surgery, the presence of arrhythmias and the circadian changes of heart rate variability were estimated by ambulatory electrocardiographic monitoring and the filtered P duration was evaluated by signal-averaged electrocardiogram. RESULTS: Restoration of sinus rhythm was observed in 73 of 100 cases. Subjects were classified into three groups according to their postoperative ambulatory electro-cardiographic monitoring findings: patients in group 1 (n = 73) (1a: 58 regular sinus rhythm; 1b: 15 sinus rhythm with frequent premature atrial contractions (> 1000/day); patients in group 2 (n = 21) still had persistent atrial fibrillation; and patients in group 3 (n = 6) required permanent pacemaker implantation because of sick sinus syndrome. The success rate of restoration of sinus rhythm was 88.3% if left atrial diameter was small (< 65 mm). Circadian changes in the low frequency to high frequency power ratio in group 1a were significantly diminished compared with control group (P < 0.01). Furthermore, the filtered P duration in group 1a (150 (20) ms) and group 1b (158 (23) ms) were longer than in the control group (122 (11) ms) (P < 0.01). CONCLUSIONS: The maze procedure may result in a decreased sinus response and non-uniform transmission of impulses in the atrium.

Clinical Study of Platelet Function and Coagulation/ Fibrinolysis With Duraflo Ii Heparin Coated Cardiopulmonary Bypass Equipment

This clinical study was performed to evaluate the effects of Duraflo II heparin coated cardiopulmonary bypass equipment on platelet and coagulationsol;fibrinolysis activation. Twenty-four patients undergoing coronary artery bypass grafting were assigned to two groups using either heparin coated (Duraflo group, n=13) or uncoated equipment (control group, n=11). In the Duraflo group, the cardiotomy reservoir was also coated with heparin. Standard systemic heparinization was performed in both groups. There were no significant differences in activated clotting times or plasma free hemoglobin concentrations between the two groups. Platelet loss and platelet activation, as measured by increases in plasma β-thromboglobulin (β-TG) and platelet factor 4 (PF4), in the Duraflo group (β-TG:237 ± 143 ngsol;ml, PF4:167 ±104 ngsol;ml at the end of cardiopulmonary bypass) were less than those in the control group (β-TG:373 ±131 ngsol;ml, PF4:295 ±131 ngsol;ml at the end of cardiopulmonary bypass). No significant differences were found in thrombinantithrombin III complex levels or α2 plasmin inhibitorplasmin complex levels between the groups. Therefore, the use of Duraflo II heparin coated equipment with a heparin coated cardiotomy reservoir suppressed platelet activation.

Risk Factors for Hypoxemia After Surgery for Acute Type A Aortic Dissection

PurposePostoperative hypoxemia is a frequent complication of surgery for acute type A aortic dissection. We tried to determine the factors associated with postoperative hypoxemia.MethodsBetween 1997 and 2003, 114 patients underwent surgery for acute type A aortic dissection. Multivariate logistic regression analysis was done to identify the independent predictors of postoperative hypoxemia, defined by an arterial partial oxygen/inspired oxygen fraction (PaO2/FiO2) ratio of 200 or lower.ResultsThe overall in-hospital mortality was 6.1% (7 of 114 patients), being 5.2% in the hypoxemia group and 6.9% in the non-hypoxemia group. The ventilation time and intensive care unit stay were significantly longer in the hypoxemia group than in the non-hypoxemia group (P = 0.0044, P = 0.038, respectively). Logistic regression identified the following variables as predictors for postoperative hypoxemia: body mass index ≥25 (odds ratio [OR], 5.6; 95% confidence interval [CI], 2.1–15.01; P < 0.001), preoperative PaO2/FiO2 ratio ≤300 (OR, 2.6; 95% CI, 1.09–6.13; P = 0.031), and the volume of transfused blood (OR, 1.08; 95% CI, 1.01–1.18; P = 0.037).ConclusionsInitiating early treatment for hypoxemia and reducing the volume of blood transfused intraoperatively may improve the postoperative clinical course of obese patients with preoperative hypoxemia.

Aortic valve repair in dominant aortic regurgitation.

OBJECTIVE We studied immediate and mid-term results after aortic valve repair. METHODS Immediate and mid-term results were studied in 63 patients undergoing aortic valve repair, calculating survival and reoperation free rates. RESULTS Subjects were 49 men and 14 women aged 15 to 76 years (mean: 53 +/- 17 years). Mean preoperative aortic regurgitation grading of 1 to 4 was 3.2 +/- 0.7. Mean preoperative New York Heart Association functional class was 1.9 +/- 0.8. Two in-hospital deaths occurred. (3.2%) Mean aortic regurgitation grade at discharge was 1.3 +/- 0.8 (p < 0.0001; vs preoperative grade) and functional class was 1.1 +/- 0.2 (p < 0.0001; vs preoperative class),--significantly improved. Overall follow-up was 98.4%, and mean follow-up continued 41.4 +/- 22.1 months. Mean functional class at follow-up was 1.2 +/- 0.4 (n = 49), improved from preoperative class (p < 0.0001). Mean aortic regurgitation grading at follow-up was 1.8 +/- 0.8 (n = 41), improved from preoperative grading (p < 0.0001). Five-year survival was 95.1 +/- 2.8%. One-year reoperation freedom was 96.6 +/- 2.4% and 5-year 77.9 +/- 6.9%. CONCLUSIONS Survival after surgery was good, while reoperation was comparable to other reports but less satisfactory compared to reoperation freedom after aortic valve replacement. Based on reoperative findings, a change in indication was made. We believe technical refinements could improve postoperative results.