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Biomedical subjects

Y Kosakai

Publications and source records attributed to Y Kosakai.

At least 19 recordsLinked to original sources
PubMed2001

Minimally invasive surgery for lung cancer with coronary artery disease.

We report a 69-year-old woman with lung cancer and severe stenosis in the left anterior descending coronary artery. To perform a curative operation for the lung cancer without myocardial infarction, minimally invasive direct coronary artery bypass and left lower lobectomy with video-endoscopic assistance were performed simultaneously. There was no major complication, and she was discharged at 14 days after the operation. This procedure may be useful and safe for patients with lung cancer and coronary artery disease.

Adenocarcinoma↗
PubMed2001

Long-term follow-up of atrial contraction after the maze procedure in patients with mitral valve disease.

OBJECTIVES: We sought to determine the effectiveness of the maze procedure for maintaining sinus rhythm and atrial contraction for a long period in patients with mitral valve disease. BACKGROUND: Although the maze procedure for atrial fibrillation (AF) has been effective in restoring sinus rhythm in patients with mitral valve disease, the long-term results of this procedure have not been determined. METHODS: We echocardiographically studied 94 consecutive patients with mitral valve disease before, as well as early (3.1 +/- 3.3 months) and late (2.2 +/- 0.9 years) after, the maze procedure. Peak velocity and the time-velocity integral of the left ventricular (LV) diastolic filling wave during atrial contraction (A wave), as well as the atrial filling fraction (calculated as the ratio of the time-velocity integral of the A wave to total diastolic filling), were obtained from transmitral flow recordings. Peak A wave velocity > or =10 cm/s was considered to indicate echocardiographic evidence of effective atrial contraction. RESULTS: Regular rhythm with P waves was restored in 70 patients (74%) in the early stage and in 59 patients (63%, p = 0.09) in the late stage after the maze procedure. Forty-seven patients (50%) in the early stage and 36 patients (38%, p = 0.14) in the late stage showed effective atrial contraction by Doppler echocardiography. Left atrial (LA) and LV end-diastolic diameters significantly decreased after the procedure (from 59 +/- 13 to 48 +/- 7 mm, p < 0.01; and from 54 +/- 9 to 47 +/- 5 mm, p < 0.01, respectively) and did not show significant changes during the follow-up period. Once atrial contraction was resumed, its degree did not change between the early and late stages after the maze procedure (17 +/- 6% vs. 17 +/- 6% for atrial filling fraction). CONCLUSIONS: Sinus rhythm and atrial contraction recovered early after the maze procedure in most patients and were maintained for more than two years. Once active atrial contraction was resumed, the degree of contraction did not change thereafter. These results demonstrate that the maze procedure is effective for a long period in patients with mitral valve disease.

Adult↗
PubMed2000

Mode of onset of ventricular fibrillation in patients with Brugada syndrome detected by implantable cardioverter defibrillator therapy.

OBJECTIVES: We sought to demonstrate the mode of spontaneous onset of ventricular fibrillation (VF) in patients with Brugada syndrome. BACKGROUND: The electrophysiologic mechanisms of VF in Brugada syndrome have not been fully investigated. METHODS: Nineteen patients (all male, mean age 47 +/- 12 years) with Brugada syndrome were treated with an implantable cardioverter defibrillator (ICD). The implanted devices were capable of storing electrograms during an arrhythmic event. We investigated the mode of spontaneous onset of VF according to the electrocardiographic features during the episode of VF, which were obtained from stored electrograms of ICDs and/or electrocardiographic (ECG) monitoring. RESULTS: During a follow-up of 34.7 +/- 19.4 months (range 14 to 81 months), 46 episodes of spontaneous VF attacks were documented in 7/19 (37%) patients. The event-free period between ICD implantation and the first spontaneous occurrence of VF was 14.6 +/- 12.1 months (range 3.7 to 27.4 months). We investigated 33/46 episodes of VF, for which electrocardiographic features (10 to 20 s before and during VF) were obtained from ICDs and/or ECG monitoring in five patients. A total of 22/33 episodes of VF were preceded by premature ventricular contractions (PVCs), which were almost identical to the initiating PVCs of VF. Furthermore, in three patients who had multiple VF episodes, VF attacks were always initiated by the same respective PVC. The coupling interval of the initiating PVCs of VF was 388 +/- 28 ms. CONCLUSIONS: Spontaneous episodes of VF in patients with Brugada syndrome were triggered by specific PVCs. These findings may provide important insights into the pathophysiological mechanisms causing VF in Brugada syndrome.

Bundle-Branch Block↗
PubMed2000

Intragastric migration of a pacemaker implanted in the pleural space.

We have encountered a 12-year-old boy with a pacemaker implanted in the left pleural space during early infancy that migrated into the stomach through the diaphragm due to severe scoliosis and occult infection. The intrathoracic implantation of a pacemaker in an infant should be assessed more carefully, taking the volume of the unit into consideration, because of this potentially life-threatening complication.

Child↗
PubMed2000

Differences in left ventricular response between rheumatic and myxomatous mitral valve disease following mitral valve replacement.

OBJECTIVE: We studied whether differences exist between hearts having rheumatic mitral valves and those having myxomatous mitral valves, in functional, geometrical, and mass changes in the left ventricle after mitral valve replacement. METHODS: Patients who underwent mitral valve replacement without preservation of annular-papillary continuity for pure mitral incompetence were classified into rheumatic and myxomatous based on valvular histopathology. Echographic data measured before surgery was compared to that about 3 weeks after surgery. RESULTS: In the rheumatic group, ejection fraction decreased from 57.5 +/- 10.8 to 47.7 +/- 12.0, indexed left ventricular internal dimension in systole (mm/m2) from 24.7 +/- 6.8 to 20.7 +/- 6.2 (P = 0.0001), and left ventricular mass index (g/m2) from 205 +/- 55 to 138 +/- 54 (P = 0.0002). In the myxomatous group, ejection fraction decreased from 60.4 +/- 11.6 to 39.7 +/- 14.5 (P = 0.0001), indexed left ventricular internal dimension in systole from 24.2 +/- 5.6 to 23.1 +/- 5.5, and left ventricular mass index from 195 +/- 83 to 111 +/- 72 (P = 0.0004). Mean wall thickness index and relative wall thickness showed significant differences between the two groups postoperatively but no significant difference preoperatively. CONCLUSION: Hearts dilated due to chronic mitral incompetence respond differently after valvular replacement with total chordal excision depending on whether a rheumatic or myxomatous mitral valve is involved.

Chordae Tendineae↗
PubMed2000

Recurrent incompetence of repaired floppy mitral valves and the severity of myxomatous degeneration.

The purpose of this study was to clarify whether or not severe myxomatous degeneration impairs the stability of a repaired mitral valve after valve-conservative surgery. A total of 21 patients who underwent successful valve-conservative surgery for pure isolated mitral incompetence were classified into two groups, one comprising those with stable mitral valve function and the other comprising those who developed recurrent incompetence within 1 year after surgery. The histological severity of myxomatous degeneration of the mitral leaflet was compared between the two groups, based upon microscopic observation and quantification of the myxomatous area in the fragment that had been surgically excised from the floppy mitral leaflet during valve-conservative surgery. The degree of myxomatous degeneration of the surgically excised fragment was significantly higher in the "recurrent" group than in the "stable" group (P = 0.02). As a microscopically confirmed severely degenerative myxomatous mitral valve may develop recurrent incompetence after valve-conservative surgery within a relatively short period, careful and regular follow-up is required.

Case-Control Studies↗
PubMed2000

Preservation of the right atrial appendage improves reduced plasma atrial natriuretic peptide levels after the maze procedure.

OBJECTIVES: The present study was conducted to determine whether preservation of the right atrial appendage lessens the decrease of plasma atrial natriuretic peptide levels after the maze procedure and whether the increase of plasma atrial natriuretic peptides improves the ability of the kidneys to excrete the fluid load after the operation. METHODS: We evaluated 42 patients who underwent the maze procedure. The right atrial appendage was preserved in 22 patients but not in 20. Blood samples were obtained before and after the operation for measurement of atrial natriuretic peptides. To evaluate the influence of atrial natriuretic peptides on the ability of the kidneys, we also measured body weight, fluid balance, and the doses of furosemide and dopamine administered after the operation. RESULTS: The restoration to sinus rhythm at 1 month after was comparable in the two groups. Plasma atrial natriuretic peptide levels significantly increased after the operation in patients in whom the right atrial appendage was preserved (1 day after: 23.4 +/- 17.8 vs 3 days after: 42.7 +/- 23.6 and 7 days after: 36.3 +/- 23.7 pg/mL, P <.05) but not in patients in whom the right atrial appendage was not preserved (1 day after: 20.0 +/- 19.6, 3 days after: 28.5 +/- 19.3, and 7 days after: 23.0 +/- 16.1 pg/mL). Furthermore, plasma atrial natriuretic peptide levels were significantly lower in patients in whom the right atrial appendage was not preserved than in patients in whom the right atrial appendage was preserved at 3 and 7 days after the operation. The fluid balance during the first 7 days of the postoperative period was comparable in the two groups, although the total dose of dopamine used in the same period was significantly smaller in patients in whom the right atrial appendage was preserved than in patients in whom the right atrial appendage was not preserved (155.3 +/- 119.0 vs 244.9 +/- 129.0 microg/kg, P <.05). CONCLUSIONS: The present study showed that preservation of the right atrial appendage lessens the decrease of plasma atrial natriuretic peptide levels after the maze procedure and that increased plasma atrial natriuretic peptides may improve the ability of the kidneys to excrete the fluid load after the operation.

Atrial Appendage↗
PubMed2000

Treatment of atrial fibrillation using the Maze procedure: the Japanese experience.

The results of a questionnaire survey show that surgical treatment for atrial fibrillation (AF) has been performed in more than 2,500 patients in Japan. The methods of treatment used were the Cox-Maze-II procedure, the Cox-Maze-III procedure, the Kosakai-Maze procedure, the left atrial Maze procedure, the right atrial Maze procedure, compartment operation, radial operation, and other modifications. The success rates of the right atrial Maze procedure and compartment operation for AF associated with congenital heart disease were approximately 50%. These success rates were significantly lower than those of the other procedures (P < .005), which were more than 70%. Among the latter procedures, there was no significant difference in success rate. In the author's experience, atrial tachycardias caused by micro-re-entries or acceleration of automaticities were seen in approximately 50% of unsuccessful cases. Any type of Maze procedure can be used to cure atrial arrhythmia that is caused by macro-reentries alone. In the future it will be very important to establish indications for the Maze procedure and methods of simplifying the operation.

Atrial Fibrillation↗
PubMed1999

Sutured wound in myxomatous mitral valve one month after repair surgery: report of two cases.

There have been no reports concerning wound healing at the site of the suture line in myxomatous leaflets. We microscopically studied the sutured wounds in two myxomatous posterior mitral leaflets which underwent quadrangular resection of the frail middle segment followed by primary suture. The sutured wounds had a thick scar which was abundant in collagen fibers about 1 month after the repair surgery. This suggests that severe myxomatous degeneration itself would not be a cause of wound dehiscence, and that a sutured wound could be a cause of rigidity and deformity of leaflets.

Humans↗
PubMed1999

Surgical treatment of Behçet's disease involving aortic regurgitation.

BACKGROUND: Behçet's disease involving aortic regurgitation is rare, and prosthetic valve detachment after aortic valve replacement is one of the most serious complications reported. We investigated the surgical results in 10 patients with aortic regurgitation caused by Behçet's disease. METHODS: Between 1981 and 1997, 10 patients with aortic regurgitation secondary to Behçet's disease had surgery. There were 8 men and 2 women, and their ages ranged from 33 to 60 years (mean, 46+/-8 years). The surgical procedures for aortic regurgitation were aortic valve replacement in 6 patients and Bentall type operation in 4. RESULTS: No patient died during the hospital stay. The follow-up periods ranged from 11 to 185 months (mean, 87 months). Two patients died during the follow-up period. The acturial survival rate was 89% at 5 years and 67% at 10 years. Prosthetic valve detachment or suture detachment requiring redo operation occurred in 4 patients, 3 of whom had redo operations twice. Four patients had a composite graft replacement, and 1 patient died after the operation. No prosthetic valve detachment was noted in 64% of the patients at 5 years and in 43% at 10 years. CONCLUSIONS: The rate of prosthetic valve detachment was 40% (4 of 10 patients), with a higher incidence in patients with Behçet's disease than in those treated during the same period at the same hospital for aortitis caused by other diseases. Surgical techniques for treatment of this condition should be modified to improve the surgical outcome in these patients.

Adult↗
PubMed1999

Surgical treatment for aortic regurgitation caused by non-specific aortitis.

Aortic regurgitation caused by non-specific aortitis is relatively rare, and prosthetic valve detachment after aortic valve replacement has been reported to be one of the most serious complications. The authors investigated the surgical results in patients with aortic regurgitation caused by non-specific aortitis. Between 1978 and 1997, 90 patients with aortic regurgitation secondary to non-specific aortitis underwent surgery. There were 28 males and 62 females. The age of these patients ranged from 19 years to 70 years (mean, 48 years). Sixty-five patients were diagnosed to have Takayasu's arteritis, 10 had Behçet's disease and 15 had aortitis of unknown etiology. The surgical procedures for aortic regurgitation were aortic valve replacement in 62 patients, Bentall-type operation in 27 and remodeling in one. Five patients (5.6%) died during the hospital stay. The follow-up duration ranged from 1 month to 224 months (mean, 98 months). Twenty-one patients died during the follow-up period, and the actuarial survival rate was 83% at 5 years and 68% at 10 years. Prosthetic valve detachment occurred in 12 patients (13.3%). Two patients required a re-aortic valve replacement, eight had a composite graft replacement and two patients underwent a homograft reconstruction. Absence of prosthetic valve detachment was noted in 83% of the patients at 5 years and in 75% at 10 years. The incidence of prosthetic valve detachment was 40% (4/10) in patients with Behçet's disease, 33% (5/15) in aortitis of unknown etiology, 4.6% (3/65) in Takayasu's arteritis and 29% (8/28) in male patients. Surgical techniques for treatment of this condition should be modified for further improvement of the surgical outcome in these patients with Behçet's disease and aortitis of unknown etiology.

Adult↗
PubMed1999

A case of constrictive pericarditis with local thickening of the pericardium without manifest ventricular interdependence.

This is the first case report of postsurgical constrictive pericarditis confined to the left ventricle in which the majority of diagnosis tests were not indicative of the disease. A 50-year-old woman with a past history of mitral valve replacement was admitted for right heart failure. Cardiac catheterization showed impaired diastolic filling but lacked the characteristic ventricular interdependence recently reported to be specific for the disease, without manifest radiological appearance of pericardial thickening. However, a new technique using magnetic resonance tagging cine revealed pericardial adhesion, limited to the left ventricle, which was confirmed during pericardiectomy. After the surgery, right heart failure and diastolic filling abnormality disappeared with restoration of normal heart pressures.

Blood Flow Velocity↗
PubMed1999

[Maze procedure for a lone atrial fibrillation].

Between 1992. 2 and 1997. 12, the maze procedure for lone fibrillation or flutter (lone af) was performed in 8 patients including 2 patients with a sustained atrial fibrillation, 5 patients with a paroxysmal atrial fibrillation and 1 patient with a sustained atrial flutter. All patients had suffered from a drug resistance lone af which induced sever symptom that is the dyspnea, palpitation and fatigue. Therefore patients requested to receive the maze procedure, and they agreed with the informed concent. After the maze operation, the normal sinus rhythm was recovered in 7 of 8 patients (87.5%). In only 1 patient, a paroxysmal atrial fibrillation remained but his symptoms improved after surgery. So this operation is a good choice of a treatment for a drug resistance lone af.

Adult↗
PubMed1998

Maze procedure for atrial fibrillation associated with atrial septal defect.

BACKGROUND: Atrial fibrillation (AF) is a relatively common complication in elderly patients with an atrial septal defect (ASD). However, use of the simultaneous maze procedure for AF associated with ASD remains controversial. We examined the efficacy and risk of the use of the maze procedure in these patients. METHODS AND RESULTS: Between March 1992 and April 1997, 26 patients underwent the maze procedure as a concomitant operation with ASD closure (maze group). Kosakai's modified maze procedure was performed in 17 patients, the modified Cox maze II or III procedure was performed in 6, and the restrictive right-sided maze procedure was performed in 3. The mean +/- SD age at surgery was 58.2 +/- 9.1 years. The mean +/- SD duration of AF was 7.8 +/- 8.5 years. The mean +/- SD left atrial dimension was 47 +/- 9 mm, and 24 patients (92%) had a larger-than-normal (> 35 mm) left atrium. The mean +/- SD follow-up period was 2.7 +/- 1.7 years. There were no hospital or late deaths. There was no thromboembolic episode in the late follow-up period. Sinus rhythm was regained in all patients who underwent conventional the right- and left-sided maze procedure except for 1 patient. However, 3 patients who underwent the restrictive right-sided maze procedure showed a return to AF rhythm. The atrial A wave was detected with the use of pulsed Doppler study in all patients who had a restored sinus rhythm. During the same period, 45 patients who were > 40 years old and without AF underwent only ASD closure (control group). The incidence of reopening the chest for bleeding was significantly (P = 0.046) higher in the maze group (12%) than in the control group (0%). Paroxysmal AF more frequently (P = 0.023) occurred in the control group (18%) than in the maze group (0%). CONCLUSIONS: These results suggest that the standard maze procedure should be considered in patients with AF associated with ASD. The restrictive right-sided maze procedure was not reliable, probably due to preoperative enlargement of the left atrium.

Aged↗
PubMed1998

[Surgical treatment for mitral regurgitation associated with secundum atrial septal defect].

We reviewed 25 patients who underwent a mitral valvuloplasty, from 1984 to 1996, for mitral regurgitation (MR) associated with atrial septal defect (ASD). Mean grade of MR was 2.3 +/- 0.7. The locations of mitral valve lesion were as follows; Postero-medial side of the anterior leaflet (AML) (11 patients: 44%), posteromedial side to center of the AML (7 patients: 28%), whole of the AML (5 patients: 20%), center of the AML (1 patient: 4%), posteromedial side of the posterior leaflet (PML) (1 patient: 4%). In summary, the mitral valve lesion was located in the AML in 96% patients and were seen in the postero-medial side of 96% patients. Mitral valve repair was performed as follows; chordae shortening only (3 patients: 12%), chordae shortening + Kay's annuloplasty (9 patients: 36%), Kay's anuloplasty (10 patients: 40%), using artificial chordae only (1 patient: 4%), using artificial chordae + Kay's annuloplasty (1 patient: 4%), using artificial chordae + ring annuloplasty (1 patient: 4%). In 24 patients, the grade of MR was less than 2/4 in the early postoperative period. In one patient, the grade of 3/4 MR was still remained. Reoperation were required in 2 patients, because of gradual increase of MR, 9 years and 10 years after the initial operation, respectively. In another patient, the grade 3/4 MR recurrently occurred at 6 months after the operation. He has been well maintained medically. In all 4 patients who had more than the grade 3/4 MR postoperatively, the annuloplasty was performed with Kay's method and the cause of MR was poor coaptation around the center of the AML. The mitral valve lesion associated with ASD seemed to be the dislocation of the AML which cause the discrepancy of the coaptation zone between both leaflets, without any prominent prolapse and chordae elongation. We put a particular emphasis on that the mitral valve repair should be performed with the recognition of the etiology of the mitral valve lesion. Especially, if the lesion extends around the center of the AML, sufficient coaptation area of both leaflets at the center of the AML should be obtained by anuloplasty.

Adult↗