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Y Kosakai

Publications and source records attributed to Y Kosakai.

At least 37 records · Page 2Linked to original sources
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↗
PubMed1998

Atrial natriuretic peptide secretion and body fluid balance after bilateral atrial appendectomy by the maze procedure.

OBJECTIVES: One of the earliest recognized postoperative complications of the maze procedure was the fluid retention in the immediate postoperative period. Routine postoperative administration of diuretics markedly reduces the frequency and severity of the fluid retention. However, the cause of the abnormal fluid balance is still uncertain. METHODS: We evaluated 24 patients: 15 patients underwent the maze procedure (maze group) and 9 patients did not (nonmaze group). Blood samples were obtained before and in the time course after operation for atrial natriuretic peptide measurement. To evaluate the influence of atrial natriuretic peptide on the body fluid balance, we also measured the amount of body fluid balance and the total doses of furosemide and dopamine administered after operation. To examine the effect of the maze procedure on atrial natriuretic peptide secretion in chronic phase, we measured plasma atrial natriuretic peptide levels during dynamic exercise in 21 patients who had undergone cardiac operations 2 years before. RESULTS: Plasma atrial natriuretic peptide levels in the nonmaze group significantly increased after operation. In contrast, plasma atrial natriuretic peptide levels in the maze group did not increase, and these levels were significantly lower than in the nonmaze group. Although significantly greater doses of furosemide and dopamine were administered to the maze group than to the nonmaze group, the body fluid balance in the maze group was comparable with that in the nonmaze group in the early postoperative period. The response of atrial natriuretic peptide secretion by exercise was significantly attenuated in the maze group (n = 12) compared with the nonmaze group (n = 9) even 2 years after surgery, although there were no significant differences in heart rate or blood pressure during exercise between two groups. CONCLUSIONS: These results suggest that the maze procedure attenuates atrial natriuretic peptide secretion in the early postoperative period and persists in chronic phase. This attenuated atrial natriuretic peptide secretion may reduce the ability of the kidneys to handle fluid load early after surgery.

Atrial Fibrillation↗
PubMed1998

Comparative efficacy of the maze procedure for restoration of atrial contraction in patients with and without giant left atrium associated with mitral valve disease.

OBJECTIVES: We sought to determine the effectiveness of the maze procedure for restoring atrial contraction in patients with and without giant left atrium (GLA). BACKGROUND: Although the maze procedure has been reported to be effective for refractory atrial fibrillation, it is unknown whether this procedure can restore effective atrial contraction in patients with GLA. METHODS: Nineteen patients with and 32 patients without GLA were studied with Doppler echocardiography before and after the maze procedure. Peak velocity and the time-velocity integral of the left ventricular diastolic filling wave during atrial contraction (A wave) and the atrial filling fraction calculated as the ratio of the time-velocity integral of the A wave to that of total diastolic filling were compared between patients with and without GLA. A 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 10 patients (53%) with and 26 (81%, p < 0.05) without GLA. Four patients (21%) with and 21 patients (66%, p < 0.01) without GLA showed effective atrial contraction by echocardiography. Once atrial contraction was resumed, the degree of atrial contraction was comparable between patients with and without GLA (17+/-5% vs. 17+/-4% for atrial filling fraction at 12 months, respectively). CONCLUSIONS: Although most patients without GLA had restored atrial contraction by the maze procedure, it was resumed in fewer patients with GLA. However, once atrial contraction was resumed, the degree of atrial contraction was comparable between patients with and without GLA. Therefore, the maze procedure may be an option in selected patients with GLA.

Aged↗
PubMed1998

Improved success rate of the maze procedure in mitral valve disease by new criteria for patients' selection.

OBJECTIVE: We have carried out the maze procedure for atrial fibrillation (AF) as a combined operation with mitral valve surgery in a consecutive fashion until December 1994 (period 1). Therefore, the success rate in sinus rhythm conversion remained unsatisfactory. We have selected the patients according to arbitrarily decided new criteria since January 1995 (period 2), and examined the results prospectively. METHODS: Between May 1992 and February 1997, we carried out the maze procedure in 220 patients as a combined operation with mitral valve surgery. During period 2, we carried out the maze procedure in 63 cases who satisfied all the new criteria (voltage of f-wave in V1 lead > 0.1 mV, cardiothoracic ratio (CTR) < 70%, LA dimension < 70 mm), and 37 patients out of these criteria. Success was defined as sinus rhythm restoration without sick sinus syndrome. RESULTS: There were 4 hospital deaths (1.8%) and 4 late deaths (1.8%). Success rate was significantly (P = 0.0089) higher in period 2 (82%) than in period 1 (65%). Success rate was significantly higher in patients within criteria than out of criteria both in period 1, period 2, and total (77 versus 48%, P = 0.018; 90 versus 66%, P = 0.004, and 83 versus 55%, P = 0.0001). CONCLUSION: The maze procedure is highly reliable when combined with mitral valve surgery if patients are selected properly.

Adult↗
PubMed1998

Increased plasma adrenomedullin concentrations during cardiac surgery.

1. Adrenomedullin (AM), a potent hypotensive peptide, was originally isolated from human phaeochromocytoma. Plasma AM concentrations are elevated in hypertension, heart failure and renal failure in proportion to the severity of the disease. This study was performed to investigate the pathophysiological significance of AM during cardiac surgery. 2. Serial blood samples were obtained from patients undergoing cardiac surgery and plasma AM concentrations were determined by specific radioimmunoassay. 3. Plasma AM concentrations did not increase with anaesthesia or surgery (n = 9). Plasma AM concentrations gradually increased during cardiopulmonary bypass and after pulmonary reperfusion. After pulmonary reperfusion, plasma AM concentrations increased further. In addition, we measured plasma AM concentrations in the pulmonary vein (n = 8) and coronary sinus (n = 8) to examine the contribution of the lungs and heart to the increase in circulating AM concentrations after cardiopulmonary bypass. However, no significant differences were seen in plasma AM concentrations of the pulmonary vein or the coronary sinus and the aorta. Peak AM concentrations during cardiac surgery correlated with duration of surgery. Elevated plasma AM levels during and after surgery began to decline next day after surgery and returned to normal levels 7 days after surgery. 4. These results demonstrate that plasma AM concentrations increase during cardiac surgery and that the duration of surgery may be related to the changes in AM concentrations. Taken together with recent findings that vascular endothelial cells and vascular smooth muscle cells actively produce AM, these results suggest that plasma AM during cardiac surgery may act as a vasodilatory hormone.

Adrenomedullin↗
PubMed1998

Surgical treatment for aortic regurgitation caused by Takayasu's arteritis.

Aortic regurgitation (AR) caused by Takayasu's arteritis is relatively rare. We investigated the surgical results in patients with AR caused by Takayasu's arteritis. Between 1978 and December 1997, 65 patients (5 males, 60 females) with AR secondary to Takayasu's arteritis underwent surgery. The patients' ages ranged from 19 to 70 years (mean, 48 years). Takayasu's arteritis was diagnosed by clinical examination confirmed by intraoperative pathological examination of the aortic wall. The surgical procedures for AR were aortic valve replacement in 45 patients, Bentall-type operation in 19, and remodeling in 1. Four (6.2%) patients died during the hospital stay. The follow-up period ranged from 3 to 227 months (mean, 111 months). Eleven patients died during the follow-up period, and the actuarial survival rate was 87% at 5 years and 75% at 10 years. The incidence of prosthetic valve detachment was 4.6% (3/65). Three patients required a composite graft replacement. No prosthetic valve detachment was noted in 96% of the patients at 5 years and in 94% at 10 years. Preoperative steroid administration to treat inflammation and its postoperative use to control inflammation may be important in the treatment of these patients.

Adult↗
PubMed1998

[Surgical treatment for prosthetic valve endocarditis].

From April 1993 to May 1997, 21 patients underwent surgical treatment for prosthetic valve endocarditis (PVE). There were 13 males and eight females aged from 46 to 79 years old (mean 62 years). There were four cases of early PVE (onset of PVE within 60 days from previous valve replacement), and 17 cases of late PVE (after 60 days). The predominant organisms were Staphylococcus epidermidis (eight cases), Staphylococcus aureus (two cases), MRSA (one case), streptococcal species (three cases), Candida (two cases), Pseudomonas cepacia (one case) and Enterococcus (one case). The predominant organisms were identified in 16 of 20 cases by preoperative blood culture, and in 11 of 20 cases by intraoperative tissue culture, and in 19 cases in all. There were four cases of preoperative cerebral complications, and three cases resurged. The hospital mortality rate was 24% (five patients). Reoperation was required in four patients for recurrence of PVE. Autopsy was performed in four of five patients. Intramyocardial abscess was detected in three patients. Earlier diagnosis and earlier surgical treatment could prevent emboli due to vegetations, which might cause catastrophic results, and could achieve better outcomes. Identification of the predominant organisms, especially from operative tissue cultures, is required.

Aged↗
PubMed1997

Pulmonary autograft implantation in the dilated aortic annulus.

The application of the pulmonary autograft (Ross) procedure in the treatment of dilated aortic annulus is still controversial, because technical errors of implantation are more likely to occur as the host annular diameter increases. The Ross procedure was successfully employed in a 28-year-old woman with a dilated aortic annulus after simple annular plication. The annulus was plicated beneath the three commissures where the pulmonary autograft was subsequently attached. The diameter of the annulus was reduced from 32 to 26 mm. This technique may provide a number of advantages compared with aortic valve replacement, especially for women of child-bearing age.

Adult↗
PubMed1997

Surgical management of Behçet's aortitis: a report of eight patients.

BACKGROUND: Behçet's aortitis is one of the most severe manifestations of Behçet's disease. However, there have been few reports of this rare entity. This article we describe our experience with surgical treatment of Behçet's aortitis in 8 patients. METHODS: From May 1978 to February 1995, we operated on 8 patients with Behçet's aortitis. All patients were followed up for a total of 54.4 patient-years (mean, 6.8 years). RESULTS: There were no operative deaths, but 1 patient died in the hospital of ventricular fibrillation. Another death occurred as a result of pseudoaneurysm rupture 10 months after operation. Fourteen operations were performed on eight patients: a second operation was performed on four patients, and a third operation was performed on two patients. The translocated Bentall procedure, a modified Bentall procedure, was performed six times. One patient required a second operation for graft detachment, but the others have done well without further surgical intervention. Aortic valve replacement was performed six times, and three reoperations were needed after aortic valve replacement. CONCLUSIONS: The translocated Bentall procedure may be effective for Behçet's aortitis, but further investigation is necessary.

Adult↗
PubMed1997

Pre- and postoperative exercise capacity associated with hemodynamics in adult patients with atrial septal defect: a retrospective study.

OBJECTIVE: This study evaluated the pre- and postoperative exercise capacity in adult patients with atrial septal defect (ASD) associated with hemodynamic variables. METHODS: Adults (70) with ASD underwent symptom-limited exercise tests. Peak O2 uptake (Peak VO2) and % peak VO2, that is the percentage of predicted value, were measured. These patients were divided into three groups according to pulmonary-to-systemic flow ratio (Qp/Qs) and systolic pulmonary arterial pressure (PAs); Group A: Qp/Qs < or = 3, PAs < or = 50 mm Hg, Group B: Qp/Qs > 3, any PAs, Group C: Qp/Qs < or = 3, PAs > 50 mm Hg. Exercise test was repeated in 22 patients after surgical closure of ASD (mean 4.6 +/- 2.0 months). RESULTS: Peak VO2 was significantly lower in group B (P < 0.01) and group C (P < 0.01) than in group A (19.3 +/- 5.7, 17.6 +/- 3.6, 27.6 +/- 6.3 ml/min/kg, respectively). In patients except those in group C, there were a weak negative correlation between PAs and % peak VO2 (r = 0.61) and a significant negative correlation between Qp/Qs and % peak VO2 (r = 0.86). Postoperative peak VO2 increased significantly in group A (27.2 +/- 5.1-31.1 +/- 5.1 ml/min/kg, P < 0.05) and group B (16.7 +/- 3.3-21.5 +/- 2.1 ml/min/kg, P < 0.01). However, there was no significant difference between pre- and postoperative peak VO2 in group C (16.8 +/- 1.3-17.8 +/- 2.8 ml/min/kg, NS). CONCLUSIONS: In ASD patients except those with small or moderate left-to-right shunt and high pulmonary arterial pressure, there was a significant negative correlation between Qp/Qs and peak VO2 corrected by age and gender. Patients with large left-to-right shunt and/or high pulmonary arterial pressure had reduced exercise capacity. However, exercise capacity in patients with large left-to-right shunt increased after closure of ASD regardless of whether they had high pulmonary arterial pressure.

Adult↗
PubMed1997

Delayed improvement of autonomic nervous abnormality after the Maze procedure: time and frequency domain analysis of heart rate variability using 24 hour Holter monitoring.

OBJECTIVE: To analyse heart rate variability in patients with atrial fibrillation after the Maze procedure, to investigate whether the procedure damages the cardiac autonomic fibres supplying the sinus node. DESIGN AND PATIENTS: Time and frequency domain analyses of RR variability were performed using 24 hour Holter monitoring one month after surgery in 12 patients with atrial fibrillation who underwent the Maze procedure (Maze group) and in seven patients who underwent cardiac surgery without the Maze procedure (control group). Mean RR intervals (mRR) and the standard deviation of successive RR intervals (SDRR) were determined by time domain analysis, and high frequency (HF), low frequency (LF), and total power (TP) spectral components of RR variability were calculated by frequency domain analysis. Holter monitoring was also performed at six and 12 months after cardiac surgery in the Maze group. RESULTS: Circadian variation (mean (SD)) in mRR (daytime to night time difference: 119 (60) v 302 (143) ms), SDRR (daytime: 8.4 (3.3) v 37.0 (12.0) ms), TP (daytime: 46.7 (16.0) v 171.8 (30.4) ms), HF (daytime: 19.6 (9.9) v 36.7 (7.1) ms2), and LF/HF (daytime: 0.31 (0.07) v 1.18 (0.46)) was decreased in the Maze group at one month compared with the control group (p < 0.01), but showed improvement at six and 12 months (p < 0.05). CONCLUSIONS: Surgery combined with the Maze procedure markedly suppressed the circadian variation of heart rate over a 24 hour period within one month after surgery, mainly because of damage to the innervation of the sinus node. However, at six and 12 months there was restoration of circadian variation, probably as the result of reinnervation of the sinus node.

Analysis of Variance↗
PubMed1997

Electrophysiologic changes in arrhythmogenic substrate following the maze procedure in patients with lone and paroxysmal atrial fibrillation.

Although the Maze procedure is highly successful in restoring sinus rhythm in patients with atrial fibrillation (AF), the electrophysiologic changes that occur after the Maze procedure and its mechanism of action are still unclear. The aims of the present study were to examine the electrophysiologic changes that occur in the arrhythmogenic substrate after the Maze procedure and to evaluate the mechanism by which it prevents lone and paroxysmal AF. The modified Maze procedure was performed in 6 patients (6 men, mean age 47 +/- 7 years) with lone and paroxysmal AF. Electrophysiologic studies were performed before and 35 +/- 8 days after the Maze procedure. Atrial mapping during sinus rhythm revealed that atrial activation propagated smoothly in a concentric circle from the sinus node to other regions in the right atrium and into the coronary sinus before the Maze procedure. Following the Maze procedure, atrial activation propagated selectively through routes produced by incisions or cryoablations in all 6 patients. In addition, double and triple potentials were recorded in regions where conduction blocks were created by the Maze procedure. Neither sinus node function nor AV conduction was changed following the Maze procedure. The Maze procedure did not affect the atrial effective refractory period or the zone of fragmented atrial activity, although the conduction delay zone was increased significantly (p < 0.05). AF was inducible in all 6 patients before the Maze procedure, whereas it was not inducible in any patients after the Maze procedure. The Maze procedure is effective in preventing AF without affecting sinus node function and AV conduction. Intra-atrial conduction block produced by incisions or cryoablations contributes to the prevention of AF.

Adult↗
PubMed1997

Huge aneurysm of the sinus of Valsalva following infective endocarditis in Behçet's disease.

A huge aneurysm of the sinus of Valsalva with conduction disturbance as a consequence of infective endocarditis in Behçet's disease is reported. The aneurysm extended not only into the ventricular septum but also to the right atrium and ventricle, with a complicated cavity formation. We speculate that complete atrioventricular block occurred due to an enlargement of the aneurysm into the ventricular septum, leading to a direct conduction system injury. Preoperative echocardiography and aortography were insufficient to recognize the extent of the lesion; subsequent operative examination revealed the true size. At operation, it is important to understand the lesion dimensions fully in order that appropriate surgical procedures be performed.

Aortic Aneurysm↗
PubMed1997

[Aortic valve replacement with stentless porcine aortic valve].

The Toronto stentless porcine valve (TSPV) is a stentless porcine aortic valve, preserved with glutaraldehyde solution, which has been designed to maintain natural laminar blood flow and improve hemodynamic performance and enhance durability. Aortic valve replacement with TSPV was performed in seven patients. The reason for this indication was advanced age (65 years or more) in six patients and connective tissue disease in another patient. One patient required reoperation because of prosthetic valve endocarditis 4 months after implantation. There were no other valve-related complications. Echocardiographic examination of prosthetic valve function one month after surgery showed no aortic regurgitation in any patient. Transprosthetic gradient was 15.1 +/- 5.0 mmHg. Technical know-how is required for the implantation. The hemodynamic characteristics of the TSPV were excellent. Further follow-up is required to determine durability, but further extensive indication of this valve is expected as a bioprosthesis.

Adult↗
PubMed1997

Choice of replacement valve in the elderly.

BACKGROUND AND AIMS OF THE STUDY: Little comparative information exists on the outcome of the valve replacement with bioprostheses or mechanical valves in the elderly. This study was carried out to make such a comparison. METHODS: Follow up data were examined from 219 patients aged > or = 65 years who underwent aortic and/or mitral valve replacement using bioprosthetic (n = 67) or mechanical valve (n = 152) between April 1979 and December 1993. The mean follow up periods were 6.3 +/- 2.8 years after bioprosthesis and 4.9 +/- 2.1 years after mechanical valve implantation. RESULTS: Although the actuarial rate of structural deterioration was higher in patients with bioprosthetic valves than in those with mechanical valves (58% versus 100% freedom at 10 years after surgery, p < 0.01), no such prosthesis-related difference was seen in the subgroup of patients aged > or = 70 (100% versus 100% at nine years, p = N.S.). The actuarial rate of major bleeding was higher after mechanical valve implantation than after bioprosthetic valve placement (90% versus 100% freedom at 10 years, p < 0.05); this lower rate with bioprosthetic valves was maintained in patients aged > or = 70 (78% versus 100% at nine years, p < 0.05). There were no significant differences in the incidences of thromboembolism and bacterial endocarditis between the two valve types. CONCLUSIONS: Structural degeneration of bioprosthetic devices was a major problem in patients aged 65-70 years, but it was essentially negligible in those aged > or = 70 years. Anticoagulant-related bleeding was a major problem with mechanical valves in both age groups. Therefore, for patients older than 70 years, valve replacement with a bioprosthesis appears to be the method of choice.

Age Factors↗
PubMed1997

[Extensive indication of mitral valvuloplasty for non-rheumatic mitral regurgitation and postoperative QOL].

Between January 1993 and June 1996, 108 patients with non-rheumatic mitral regurgitation (MR) underwent surgical treatment. Mitral valvuloplasty (MVP) was performed in 94 patients (87%) and mitral valve replacement (MVR) was performed in 14 patients. The patients were reviewed based on the location of the prolapse, active endocarditis, and re-valvuloplasty. The proportion of MVP patients to the total number of cases was 92%, 96% and 94% for prolapse of the anterior mitral leaflet (MVP: n = 22), the posterior mitral leaflet (n = 47) and of both leaflets (n = 15), respectively; it was 60% and 33% in the patients with active infective endocarditis (n = 3) and in reoperation cases (n = 3). Reoperation was required in 2 patients. Other than reoperation cases, 3/4 grade MR was detected by color Doppler echocardiography in 6 patients although they were asymptomatic. Thromboembolism occurred in 3 patients. The event-free rate at 42 months was 80.4%. Concomitant maze procedure was performed in 36 of 39 patients with atrial fibrillation and normal sinus rhythm was obtained in 25 of the 36 patients. Only 6 patients received warfarin anticoagulation after MVP. In current cases with non-rheumatic MR, the MVP could be performed in 87% of all patients and in 94% of the patients with simple prolapse, regardless of the prolapse area. Concomitant maze procedure might provide a better quality of life after MVP.

Adult↗