Shigehito Miki

Mitral Valve Replacement with Preservation of Chordae Tendineae and Papillary Muscles

An operative technique for mitral valve replacement (MVR) with preservation of the chordae tendineae to the anterior leaflet as well as the posterior leaflet is reported. This technique consists of the division of the anterior leaflet into anterior and posterior segments, the shifting and reattachment of the divided segments to the mitral ring of the respective commissural areas, and the use of a low-profile bileaflet prosthetic valve. A comparison of left ventricular function data between patients having operation with this technique and those having operation with the conventional method of MVR revealed significantly better improvement in cardiac index (p less than 0.06), left ventricular end-systolic volume index (p less than 0.05), and left ventricular ejection fraction (p less than 0.10) in the former group. Left ventricular wall motion improved in the anterolateral (p less than 0.01) and apical areas (p less than 0.02) in patients operated on with our technique. Maintenance of continuity between the mitral annulus and papillary muscles is expected to have a beneficial effect on postoperative left ventricular performance in spite of increased afterload.

Deep Hypothermic systemic circulatory arrest and continuous retrograde cerebral perfusion for surgery of aortic arch aneurysm

From 1987 to February 1991, we have repaired or replaced the aortic arch in ten patients using deep hypothermic systemic circulatory arrest with continuous retrograde cerebral perfusion (CRCP). CRCP can be implemented using the bypass connecting the arterial and venous lines of the extracorporeal circuit to reverse the flow into the superior vena cava cannula after induction of circulatory arrest. CRCP flow required to maintain an internal jugular vein pressure of 20 mmHg ranged from 100 to 500 ml/min. After completion of suturing of the aortic arch graft, air is evacuated retrogradely from the open arch vessels prior to reestablishing the usual arterial return. Two patients died, one from sepsis and the other from liver cirrhosis 1 month postoperatively. CRCP times ranged from 11 to 56 min, and minimal nasopharyngeal temperatures ranged from 16 degrees to 18 degrees C. The difference in oxygen content between the perfused blood and the blood draining from the arch vessels during CRCP most likely reflected the steady-state metabolism of the brain during the deep hypothermic state. This technique offers advantages including the need for dissecting and clamping the arch branches, providing sufficient metabolic support to the brain during deep hypothermia, and eliminating embolism of particulate debris from the aortic arch.

Intractable Hemolysis Caused by Perivalvular Leakage Following Mitral Valve Replacement with St. Jude Medical Prosthesis

Nine patients with intractable hemolysis caused by perivalvular leakage following mitral valve replacement with a St. Jude Medical prosthesis are presented. All patients had dark-colored hemoglobinuria, which appeared from 1 day to 44 days after the operation, with moderate or severe hepatorenal insufficiency. One patient died of multiorgan failure. The other 8 patients underwent reoperation, and all survived. Reoperation revealed that all leakages were tiny and had no adverse effect on hemodynamics. In all the patients having reoperation, hemoglobinuria disappeared immediately after the procedure. Surface-scanning electron microscopy of the sewing cuff of the St. Jude Medical prosthesis revealed the rough surface structure of the sewing ring. Because of this irregular, shaggy surface structure, greater shearing forces against erythrocytes can be generated when there is perivalvular leakage.

Aneurysm of coronary arteriovenous fistula presenting as a calcified mediastinal mass

A 61-year-old woman with a giant aneurysm of the coronary arterial fistula between the left anterior descending coronary artery and the main pulmonary artery underwent aneurysmal resection and closure of the fistula. This was a very unusual case with rare congenital malformation with secondary atherosclerotic change.

Annuloplastic reconstruction for common atrioventricular valvular regurgitation in right isomerism

Two patients who had common atrioventricular valvular regurgitation associated with right isomerism, univentricular heart of the right ventricular type, transposition of the great arteries, pulmonary stenosis, and both systemic and pulmonary venous anomalies underwent common atrioventricular valvular annuloplasty. They also underwent bilateral, bidirectional cavopulmonary shunt. A Carpentiers ring was used in patient 1 and a polytetrafluoroethylene tube was used in patient 2 to reduce the diameter of the common atrioventricular annuli. Postoperative catheterization confirmed complete elimination of regurgitation of the common atrioventricular valve in both patients.

High origin of the right coronary artery with congenital heart disease

We encountered a case of anomalous high origin of the right coronary artery associated with ventricular septal defect and patent ductus arteriosus. The right coronary artery originated from the distal part of the ascending aorta resulting in unsuccessful induction of cardiac arrest by cardioplegia. We describe this rare case with anomalous origin of the right coronary artery.

Early and late results of repair of tetralogy of Fallot with subarterial ventricular septal defect. A comparative evaluation of tetralogy with perimembranous ventricular septal defect.

Between November 1966 and December 1990, 511 pediatric patients with tetralogy of Fallot underwent corrective operation at Tenri Hospital. There were 78 patients with subarterial ventricular septal defect. Mean age at repair was 5.6 +/- 3.3 years. The method of right ventricular outflow tract reconstruction was simple infundibulectomy in 14 patients, right ventricular ventricular outflow patch in 36, and transannular patch in 28. There were 7 (9.0%) early deaths as a result of low cardiac output syndrome and acute renal failure. The pressure ratio of the right ventricle to the left ventricle was 0.62 +/- 0.18 during the early postoperative catheterization. Follow-up was achieved for 442.6 patient-years and ranged from 0.5 to 27 years, with an average of 8.5 +/- 6.7 years. There were three late deaths (2 cardiac and 1 noncardiac). Actuarial survival was 94.8% +/- 4.0% at 20 years. Catheterization during late follow-up (6.8 +/- 4.7 years after repair) was done in 53 patients and the pressure ratio of the right ventricle to the left ventricle was 0.48 +/- 0.21. Fifteen patients underwent subsequent operation because of residual lesions, including ventricular septal defect in four patients, pulmonary stenosis in nine, combined ventricular septal defect and pulmonary stenosis in one, and pulmonary regurgitation in one, with no mortality. Actuarial rate of freedom from reoperation was 71.1% +/- 8.0% at 10 years and 58.8% +/- 16.8% at 20 years. Patients with tetralogy and subarterial ventricular septal defect were more likely to have the development of residual obstruction at the level of the pulmonary valve anulus after repair than were those with tetralogy and perimembranous ventricular septal defect.

Propranolol for intractable hemolysis after open heart operation

Postoperative intravascular hemolysis occurring in 2 patients was alleviated by propranolol. One patient underwent mitral valve replacement and had development of intractable hemolysis due to a paravalvular leak. The other patient underwent ventricular septal defect closure and had hemolysis caused by the Dacron patch. Both patients were given oral propranolol, and the degree of hemolysis decreased substantially. Although the exact mechanism of the propranolol effect on mechanical intravascular hemolysis is unclear, propranolol is thought to reduce the shearing stress between erythrocytes and the foreign material by slowing the velocity of the circulation.

Reoperation after Aortic Valvuloplasty for Aortic Regurgitation Associated with Ventricular Septal Defect

Five patients underwent reoperations because residual or recurrent aortic regurgitation occurred after aortic valvuloplasty for aortic regurgitation associated with ventricular septal defect. The mean age at reoperation was 22 years old, and the mean time interval between initial and second operation was 6 years, 10 months. The pathological findings of the aortic valves showed tears and perforation of repaired leaflets in four patients and a giant pseudoaneurysm of the Valsalva sinus in one. Aortic valvuloplasties were performed again in three patients, and aortic valves were replaced with prosthetic valves in two. Slight to moderate regurgitant murmurs are still audible in patients who underwent these valvuloplasties. Ventricular septal defects should be closed before aortic regurgitation develops. If it has developed, however, valvuloplasty should be considered as a first choice in young patients. For adult patients, aortic valve replacement is recommended.

Two-Stage Repair for Aortic Regurgitation With Interrupted Aortic Arch

We performed two-stage repair for a rare adult case of interrupted aortic arch with aortic regurgitation and sinus of Valsalva aneurysm. A lateroisthmic bypass was established with minimal thoracotomy and partial clamping of the descending aorta to preserve collateral circulation. This was followed by aortic root reconstruction with a prosthetic graft and valve for aortic regurgitation with sinus of Valsalva aneurysm. This less invasive two-stage repair for such a rare pathology may facilitate smooth recovery of the patient.