ABSTRACT
We report a case of redo mitral valve replacement (MVR) for a Björk-Shiley Delrin valve implanted 47 years previously. A 71-year-old man initially underwent MVR for mitral regurgitation at our hospital at the age of 16 years. Following the operation, follow-up examinations were performed at the outpatient clinic and annual transthoracic echocardiogram findings showed only mild mitral regurgitation, with no adverse events noted. However, a transthoracic echocardiogram examination performed 45 years after the operation revealed mild to moderate mitral regurgitation, while dyspnea with exertion was also noted at that time. As part of a more detailed examination, transesophageal echocardiogram results showed moderate transvalvular leakage. Redo MVR was subsequently performed under the diagnosis of prosthetic valve dysfunction. Analysis of the explanted prosthetic valve revealed wear of the Delrin disk, and widening of the gap between the disk and strut, which were presumed to be the cause of transvalvular leakage. A half century has passed since introduction of the Björk-Shiley valve and the present is a rare case of valve malfunction. Presented here are related details, along with a review of existing literature and results of Björk-Shiley valve use at our hospital.
ABSTRACT
We report a case of transposition of the great arteries (TGA) with severe pulmonary hypertension from the right to left shunt in the right modified Blalock-Taussig shunt. The patient was diagnosed with TGA with a small ventricular septal defect, restrictive patent foramen ovale, and patent ductus arteriosus. Balloon atrial septostomy was performed, and an arterial switch operation (ASO) was planned. However, ASO was delayed during the neonatal period due to cerebral bleeding. Moreover, left outflow tract obstruction was noted ; hence, the surgical strategy was shifted to an atrial switch operation or Rastelli type operation. The patient was palliated at the age of 5 months with a right 4-mm Gore-Tex modified Blalock-Taussig shunt. After this procedure, he was followed up at the outpatient clinic with good saturation level. However, at 9 months, he revisited the hospital due to septic shock. His SpO2 was 60% in the upper right limbs and 40% in the upper left and lower limbs. Nitric oxide inhalation and 100% oxygen were administered to improve pulmonary hypertension and subsequent differential cyanosis. Pulmonary hypertension decreased from over-systemic to 70% of the systemic arterial pressure. The Senning procedure with a fenestration in an atrial baffle was successfully performed at the age of 1 year.
ABSTRACT
A study was performed to investigate the validity of the derivative of the ear densitogram for measurement of left ventricular ejection time (LVET) .<BR>Nine male college students performed bicycle exercise at an initial work load of 0 watt (W), subsequently increasing by 60W every 3 min up to 240W. The LVET derived from the derivative of the ear densitogram (LVETe) was compared with that derived from the carotid pulse wave (LVETc) obtained at the same time.<BR>The results were as follows:<BR>1. There was a high correlation coefficient, r=0.987 (P<0.01), between LVETe and LVETc.<BR>2. At rest, LVETe showed a tendency to coincide with LVETc. In contrast, LVETe became longer than LVETc during exercise, and the higher HR became, the larger the difference between the two.<BR>3. In the individual regression equations between LVETe and LVETc, the slopes and the intercepts were nearly identical.<BR>4. The following equation was proposed for the correction of LVETe during exercise. LVET=-0.147⋅HR+ LVETe+ 8.3<BR>From these findings, it was concluded that the validity of the derivative of the ear densitogram for estimation of LVET is sufficiently high. LVETe at rest is valid for the estimation of LVET without correction. During exercise, however, LVETe shows a tendency to be longer than LVETc, and thus it is desirable to correct LVETe using the above equation.