S Sato’s research while affiliated with Yamagata University and other places

We analyzed shortening patterns of the infundibulum in 11 patients with valvular pulmonary stenosis (PS) before and immediately after balloon valvuloplasty and at follow-up. The control group consisted of 32 patients with Kawasaki disease. The valvuloplasty was performed at the age of 5.8 +/- 2.9 (mean +/- SD) years and a satisfactory relief of obstruction was achieved in each. The follow-up study was done at 1.1 +/- 0.2 years after the valvuloplasty. With the use of lateral projection of right ventriculograms, transverse diameters of the midinfundibulum were measured over one cardiac cycle from initiation of the pulmonary valve opening. Indices demonstrating shortening patterns of the infundibulum were as follows: time to the beginning of shortening (TBS), time to the shortest diameter (TSD), and shortening fraction (SF). TBS were prolonged before the valvuloplasty, whereas it was comparable with that in the control group, immediately after the procedure and at follow-up. TSD was increased before and immediately after the valvuloplasty, but it was normalized at follow-up. SF was increased at every observation. Thus, shortening patterns of the infundibulum in PS were characterized by increasing TBS, TSD, and SF. At short-term follow-up following the valvuloplasty, TBS and TSD were normalized, which could be a result of a successful relief of pulmonary obstruction. In contrast, SF remained elevated, which indicates that the musculature of the infundibulum remains hypertrophic up to 1 year after the valvuloplasty.

Balloon pulmonary valvuloplasty (BPV) has been applied to tetralogy of Fallot (TOF) as a palliative procedure. To investigate the histopathologic changes by BPV in the infundibular septum of TOF, we performed histopathologic examinations of the infundibular septum resected at corrective surgery. The subjects were 5 patients with TOF, who underwent BPV at the median age of 2.2 months and the corrective surgery at the median age of 15.0 months (BPV group), and 4 patients with TOF who had no prior BPV and who underwent the corrective surgery at the median age of 14.5 months (control group). There was no significant difference between the two groups in the endocardial thickness, myocardial vacuole degeneration, or fraction of fibrous and interstitial space. However, the specimens from 3 patients in the BPV group had localized dense fibrous lesions in the myocardium. The findings in this limited sample suggest that BPV for TOF does not produce overall histopathologic alterations such as fibrosis, thick endocardium, and myocardial vacuole degeneration, but may sometimes damage the myocardium of the infundibular septum resulting in the formation of localized dense fibrous lesions. The clinical significance of this damage is still unknown, and further cases should be investigated.

We performed successful balloon pulmonary valvuloplasty (BPV) in 6 patients with pulmonary valve stenosis and atrial septal defect (ASD) accompanied by atrial left-to-right shunt without an increase of shunting immediately after BPV. It suggests that such patients should be treated by BPV initially and the need for ASD repair can be assessed during long-term follow-up.

A 4-month-old boy underwent a percutaneous balloon aortoplasty for restenosis after extended aortic arch anastomosis for type B interrupted aortic arch (IAA). Balloon aortoplasty resulted in a decrease in the peak systolic pressure gradient across the obstructive segment from 84 mmHg to 19 mmHg and in an increase in diameter from 2.5 mm to 4.3 mm. No complications related to the procedure were observed. We assume that balloon aortoplasty can be effective and safe for relieving postoperative aortic obstruction associated with IAA.

The body surface isopotential T map was analyzed to detect right ventricular volume and pressure overloads in 25 patients with secundum atrial septal defect. Three patterns were distinguished: a T map resembling normal (type A, n = 9); that with an isolated negative area in a positive area (type B, n = 11); and that with rightward movement of maximum (type C, n = 5). Right ventricular end-diastolic volumes in types B (161 +/- 19% of normal; %N) and C (175 +/- 40% N) were significantly (p < 0.01) greater than those in controls (100 +/- 9% N) and type A (113 +/- 18% N). Right ventricular systolic pressure in type C (48 +/- 11 mmHg) was significantly (p < 0.01) higher than those in the controls (30 +/- 5 mmHg), type A (31 +/- 4 mmHg), or type B (34 +/- 5 mmHg). These results suggest that the patients with type B have right ventricular volume overload and those with type C have both volume and pressure overloads.

Body surface isopotential T map was analyzed to detect right ventricular volume and pressure overloads in 25 patients with secundum atrial septal defect. Three patterns were distinguished: the T map resembling normal (type A, n = 9); that with isolated negative area in positive area (type B, n = 11); and that with rightward movement of maximum (type C, n = 5). Right ventricular end-diastolic volumes in type B (161 +/- 19% of normal; %N) and C (175 +/- 40% N) were significantly (p < 0.01) greater than those in control (100 +/- 9% N) and type A (113 +/- 18% N). Right ventricular systolic pressure in type C (48 +/- 11 mmHg) was significantly (p < 0.01) higher than those in control (30 +/- 5 mmHg), type A (31 +/- 4 mmHg) and type B (34 +/- 5 mmHg). These results suggest that the cases with type B have right ventricular volume overload, and those with type C have both volume and pressure overloads.