[Late results of coronary heart surgery. Late graft patency in coronary bypass procedure]

The graft patency was evaluated by a contrast enhanced computed tomography (CT) and/or digital subtraction angiography (DSA) in the follow up of aorto-coronary bypass surgery. One hundred and eighty-four patients included in this study received a total of 331 grafts. The Elipse S/200 Scanner for CT and Siemens Angiotron system for DSA were used for this study. Early in the study, selective coronary angiography were performed and the results were interpreted in 331 grafts and 86 grafts to evaluate the diagnostic reliability of CT and DSA for graft patency, respectively. While the CT scans correlated with angiographic assessment of graft patency showed 98% of sensitivity, 100% of specificity, and 98% of predicted accuracy, the DSA showed 95% of sensitivity, 100% of specificity and 95% of predicted accuracy, respectively. The patency rate in the early postoperative period was 94%, and the cumulative patency rate during follow up of 5 years was 93%, respectively. In summary, CT and DSA can provide useful information regarding graft patency in the long term follow up of aorto-coronary bypass surgery.

[Measurement of four chambers' volumes and ventricular masses by cardiac CT examination]

Using cardiac computed tomography (CT), the "mean" volume of each cardiac chamber and both ventricular masses were calculated from summation of a sliced volume by ungated scans obtained using rapid sequential scanning covering the whole heart. Estimation of a normal value of each chamber's volume was attempted in 20 patients with ischemic heart disease and with normal heart function. The "mean" volume of the right atrium (RAMV), right ventricle (RVMV), and left atrium (LAMV) was 22.3 +/- 6.5, 40.3 +/- 6.5 and 28.7 +/- 8.2 ml/m2, respectively. In 54 patients with valvular heart diseases, each chamber's volume obtained by CT was compared with the grade of tricuspid regurgitation (TR) estimated by ultrasonic Doppler technique or the grade of mitral regurgitation (MR) by left ventriculography (LVG). The RAMV (234 +/- 119 ml/m2) and the RVMV (101 +/- 39 ml/m2) were markedly increased in patients with severe TR (grade 3 to 4) (p less than 0.01). The LAMV (487 +/- 231 ml/m2) was also increased in patients with severe mitral regurgitation (grade 3 to 4) (p less than 0.01). In 46 patients with valvular heart diseases, the LVMV by CT was well correlated with end-diastolic volume (EDV) obtained by LVG (r = 0.92), and the LVEDVs by ECG gated CT and by LVG showed a fairly good correlation (r = 0.95). CT examination was performed before and after surgery in 17 patients with MR or TR for evaluation of the change of chamber volumes. The mean reduction ratio (MRR) of the RAMV after tricuspid annuloplasty, the LVMV after mitral valve plasty, and the LAMV after left atrial plication was 44%, 41%, and 60%, respectively.

Surgical treatment for severe congenital heart diseases

The surgical results in patients with severe congenital heart disease, who underwent surgical treatment between 1978 and 1981 at the National Cardiovascular Center, Japan, were analyzed. The surgical mortality rates were 4% for cases of ventricular septal defect associated with pulmonary hypertension in patients under 2 years of age, 16.7% for complete atrio-ventricular canal, 11% for coarctation of the aorta associated with ventricular septal defect, 40% for pure pulmonary atresia without Ebstein anomaly, 44% for total anomalous pulmonary venous return, 14.8% for transposition of the great arteries, 44% for double outlet right ventricle and 1.1% for tetralogy of Fallot. The surgical results have been improving and postoperative residua and sequelae have been decreasing through our persistent efforts. Today's main problem is a relatively poor performance in cases which need surgical intervention early in life, i.e., under 3 months of age. Therefore, we think that our effort to improve the surgical results for new-borns or very young infants is most necessary.

[Heart valve replacement with the Ionescu-Shiley bovine pericardial xenograft. Hemodynamic evaluation and early clinical follow-up of 170 patients]

The Ionescu-Shiley bovine pericardial xenograft (ISPX) has been widely accepted clinically because of its superior hemodynamic characteristics and low incidence of thrombogenicity. After confirmation by our own experiment of its superior valve performance, we have adopted in clinical application of this valve since August of 1979, and implanted 189 of this valve in 170 patients up to November of 1981. The overall mortality rate including of hospital and follow up death was 14.1%. The pressure gradient and calculated orifice area of ISPX were compared to those of Hancock xenograft (HX), and the valve characteristics of ISPXs was found to be better than those of HX. The cardiac function following implantation of this valve apparently showed improvement. No incidence of thromboembolic episode or malfunction was observed, however, prosthetic valve endocarditis (PVE) was encountered in four patients and two died. This incidence of PVE in ISPXs was not significantly higher in comparison to that in other type of prosthetic valve. However the low incidence of thromboembolic episode as well as acceptable valve performance were confirmed by our study, the durability and susceptibility to PVE has to be carefully observed in the longer follow up.

[Giant left atrium in mitral valve disease: a new plication procedure to relieve the compressions of left ventricular wall left bronchus and right lung]

The giant left atrium associated with mitral valve disease frequently produces postoperative hazardness in relation to hemodynamic and respiratory management. We have defined the most serious disorders induced by the presence of giant left atrium in three categories as follows. First, hemodynamic disturbance by the compression of left ventricular wall by downward extension of left atrium (type I), secondly, respiratory disturbance yielded by the compression of left main bronchus by upward extension of left atrium (type II), thirdly, compression of right middle lobe by rightward extension of left atrium (type III). A new procedure of para-annular, superior and right-side plication methods were derived as the procedure to relieve those compressions induced by giant left atrium. Up to the present, 47 patients with giant left atrium underwent surgery, twelve of valvular procedure only and thirty-five of valvular as well as plication procedure. The incidence of postoperative low output syndrome and respiratory failure were evaluated. The plication procedure showed marked decrease in the incidence of low output syndrome and respiratory failure postoperatively, eventual significant decrease in mortality rate. We conclude that plication procedure is very effective for the treatment of compression in the presence of giant left. atrium.

[Evaluation of left ventricular morphology and function by cardiac computed tomographic examination]

Usefulness of cardiac computed tomography (CT) in the evaluation of left ventricular (LV) morphology and function was studied in clinical practice. One hundred and forty-nine adult cases of various heart diseases were examined by GE scanner with ungated scans covering whole LV and ECG-gated scans. In gating examination, "long-axial" and "short-axial" slices were scanned and end-diastolic area (EDA), end-systolic area (ESA) and "mean" area (MA) were obtained in each slices. 1) With regard to LV morphology, wall thickening in HCM and wall thinning and mural thrombus in myocardial infarction were easily visualized. 2) LV "mean" volume (LVMV) was easily calculated from the sum of sliced LV volume of ungated scans. The LVMV was well correlated with end-diastolic volume (EDV) obtained by LV angiocardiography (LVG) (r = 0.91), though the former was somewhat smaller than the latter. EDV by CT obtained after the correction with MA/EDA from gating examination showed a better correlation (r = 0.95) and both EDV showed almost the same value. 3) LV ejection fraction (EF) was calculated by exchanging ESA/EDA to ESV/EDV in "long-axial" and "short-axial" gated slices, and "long-axial" EF, "short-axial" EF and mean of both were well correlated with LVEF of LVG (r = 0.73-0.79). 4) LVEF calculated from "long-axial" EDA and ESA by application of "area-length" method was also correlated with EF of LVG (r = 0.68), but these EDV and ESV were smaller than those of LVG due to shorter long-diameter of LV in CT. 5) LV muscle volume was calculated from sum of sliced muscle volumes of ungated scans covering LV, and LV mass was easily evaluated from LV muscle volume and specific gravity of LV muscle. This LV mass was well correlated with that of LVG (r = 0.90) and the absolute values were almost the same.