Kiroku Ohishi

The Surgical Treatment of Aortic Regurgitation Secondary to Aortitis

We describe the operative and perioperative management of 11 patients with aortic regurgitation due to aortitis. All patients required aortic valve replacement because of severely uncoapted cusps secondary to dilatation of the ascending aorta. The right coronary ostium was narrowed in 5 patients and consequently necessitated a smaller coronary tip for the administration of cardioplegic solution. To implant the prosthetic valve, pledgeted 2-0 Tevdek sutures were placed through the aortic valve annulus either from the ventricular side or from outside the aortic wall. Steroids were administered to 4 patients preoperatively and 8 patients postoperatively. Postoperative dehiscence of the prosthesis was seen in 1 of the 3 patients not given any steriods. We conclude that it is important to arrest the inflammatory reaction before operation and if the aortic valve must be replaced, to reinforce the implanted prosthesis with pledgeted sutures. Also, we suggest the possible importance of steroid therapy.

Biplane transesophageal echo-Doppler studies of atrial septal defects: Quantitative evaluation and monitoring for transcatheter closure

Forty-four patients with atrial septal defects, aged 7 months to 18 years (median 8.9), underwent biplane transesophageal (TEE) and transthoracic (TTE) echocardiography. The size of the defect and the shunt flow volume were measured by TEE and compared with the actual size at surgery (N = 14) or the shunt volume measured by the Fick method (N = 34), respectively. In all cases the location and morphology of the defect were clearly demonstrated by TEE; on the other hand, two patients with sinus venosus-type and multiple-type defects, respectively, and one with a small ostium primum defect did not have a complete diagnosis by TTE. The defect size determined by TEE correlated well with the surgical measurement. Similarly a significant correlation was demonstrated between the shunt volume measured by TEE and that obtained by the Fick method. In three patients transcatheter closure of the atrial septal defect by means of a clamshell device was accomplished successfully with TEE monitoring. We conclude that biplane TEE provides a better appreciation of cardiac anatomy and hemodynamic evaluation than TTE in this setting, and TEE is essential for monitoring during transcatheter closure.

Interrupted warm blood cardioplegia for coronary artery bypass grafting

Continuous warm blood cardioplegia has been used with good clinical outcome in both antegrade and retrograde delivery. However, the continuous delivery of cardioplegia is sometimes interrupted for adequate visualization and flow is not constant with heart manipulation during operation. We studied the effects of interrupted antegrade delivery of warm blood cardioplegia on myocardial metabolism and clinical results after surgery. Fifty-five patients undergoing isolated coronary bypass surgery received warm blood cardioplegia (n = 29) or cold crystalloid cardioplegia (n = 26) in an antegrade fashion. During reperfusion, myocardial oxygen consumption, lactate extraction, creatinine kinase isoenzyme (CK-MB), and malondialdehyde (MDA) were measured. Post-operatively, serum CK-MB and cardiac output (CO) were determined over a period of time. Myocardial oxygen extraction in the warm group was significantly greater than in the cold group 1 min after reperfusion (P < 0.02). The results revealed a tendency for patients in the warm group to have prior lactate extraction, although the difference did not reach statistic difference (P < 0.10). After removal of the aortic cross-clamp, the heart returned to sinus rhythm spontaneously in 90% of the patients with warm cardioplegia and 15.4% of those with a cold heart (P < 0.01). Postoperatively, there was no significant CK-MB or MDA release in either group except for one patient with perioperative myocardial infarction. After operation inotropic support was required for two and one patient in the warm and cold groups, respectively, although there were significantly more patients with poor left ventricular function in the warm, than in the cold, group (P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

The St. Jude medical prosthesis in the mitral position.

To study the long-term results of the St. Jude medical prosthesis in the mitral position, 520 patients were evaluated who had undergone mitral valve replacement with St. Jude medical (SJM) prosthesis. Eighteen patients or 3.5% died in the early postoperative period (within 30 days after operation). The total follow-up was 2872 patient-years and late deaths occurred in 23 cases. Postoperative cerebral embolism occurred in six, bleeding complication in five, and thrombosed valve in two patients. Postoperative anti-coagulant therapy was initiated with both dipyridamole (300 mg/day) and warfarin potassium. After discharge from our hospital the patients underwent routine examination of their thrombo-tests or prothrombin times at least every 2-3 months, and the major thromboembolic or bleeding complication rate was 0.45%/100 patient-years. In a period of 12 years, severe hemolysis following implantation was seen in seven patients. The cause of this hemolysis was perivalvular leakage in two patients but there were no leakages in the other five patients, although preoperative moderate to severe liver dysfunction was noted. Ninety-three percent of the patients were followed up, and their postoperative New York Heart Association functional classes were I or II in 88.6% of the cases. Their clinical results after mitral valve replacement with SJM prosthesis in the anti-anatomical position showed excellent durability and a low incidence of valve-related complications.

Ventricular Septal Defect Associated with Aortic Regurgitation

The effectiveness of aortic valvuloplasty and the indications for aortic valve replacement were examined in 76 patients with ventricular septal defect associated with aortic regurgitation. Results of this study indicate aortic regurgitation is associated with rapid deterioration and that aortic valvuloplasty should be performed as soon as aortic regurgitation is detected. The data also suggest that aortoplasty is indicated if aortic valvuloplasty alone is inadequate for coaptation of the aortic cusps with thickening.

Tricuspid valve replacement with the St. Jude Medical valve

A study was conducted on 20 patients who underwent tricuspid valve replacement (TVR) with the St. Jude Medical (SJM) valve. Isolated TVR was performed on 9 patients, and additional mitral, or mitral and aortic valve replacements were performed on 11 patients. Four patients (20%) died in the early postoperative period, but there were no deaths related to the SJM valve in the tricuspid position. The mean follow-up period of the 16 survivors was 74.4 months, and there have been no deaths during the follow-up period. The postoperative actuarial survival rate was 80%, 10 years after surgery. Three patients, representing 0.25%/patient-months, developed valve thrombosis, the valve thrombosis-free rate being 72.8%, 10 years after surgery, while entrapment of a leaflet by endothelial pannus was found in one patient, representing 0.08%/patient-months. Thus, the incidence of all prosthetic valve-related complications was 0.34%/patient-months, and the postoperative complication-free rate was 65.3%, 10 years after surgery. The medium-term follow-up study of TVR with the SJM valve revealed no prosthetic valve-related deaths and a relatively low incidence of prosthetic valve-related complications. However, as with other mechanical valves, valve thrombosis was a major risk posed by the SJM valve in the tricuspid position.

Long-term follow-up results after reconstruction of the mitral valve by leaflet advancement

In this study, we discuss the clinical results of mitral leaflet advancement performed on 29 patients over the past 10 years and attempt to determine the indication. Preoperative diagnosis of mitral valve lesion consisted of mitral regurgitation in 21 patients and mitral stenosis in 8 patients. Mitral valve repair was applied to the anterior mitral leaflet in 2, the posterior mitral leaflet in 25, and bilateral leaflets in 2 patients. Reoperation was performed on 13 patients, and 1 patient died of renal failure immediately after reoperation. No reoperation was needed for 96.6% of the patients at 1 year, 89.5% at 5 years, 75.0% at 8 years, 63.8% at 10 years, and 52.6% at 15 years postoperatively. At reoperation, the repaired mitral leaflet was found to be calcified in 3 patients more than 9 years after the initial operation. Of the 12 survivors without reoperation, mitral stenosis associated with regurgitation was obvious in 6 patients. Of the 21 patients with preoperative mitral regurgitation, 90.0% showed no deterioration at 5 years, 79.7% at 8 years, and 69.1% at 10 years. On the other hand, for the 8 patients with mitral stenosis, the rates were 87.5% at 1 year, 62.5% at 5 years, 50.0% at 8 years, and 25% at 10 years. Our results suggest that mitral leaflet advancement shows satisfactory results in patients with mitral regurgitation but is not successful for patients with mitral stenosis in the long term because the repaired valve tends to be stenotic in the late postoperative period.

The Internal Thoracic Artery and Its Branches After Coronary Artery Anastomoses in Pediatric Patients

The internal thoracic artery has been favored because of its superior early and late patency for coronary artery bypass grafting (CABG) in pediatric patients. We have studied the angiographic changes of the internal thoracic artery and its side branches before and after CABG with internal thoracic artery to the left anterior descending artery. The internal thoracic artery with remaining thymic or pericardial branches was patent but showed enlargement of the branches in the early period after the operation, and a postoperative exercise test suggested a remaining ischemic lesion in the bypass. Angiogram taken 1 year after CABG demonstrated the grown internal thoracic artery with disappearance of most of the side branches, which had been enlarged 1 month after the operation. Our findings suggest the importance of ligation of the whole proximal internal thoracic artery branches to maintain good early and late patency.

Morphological and functional study of free arterial grafts

SummaryMorphological and functional changes of free arterial grafts in dogs were studied for 3 weeks after implantation and the changes were compared to those in implanted free vein grafts. In the arterial grafts, endothelial cells with abundant pinocytotic vesicles and some cytoplasmic folds were observed by transmission and scanning electron microscope and cell detachment was seen only at the site of anastomosis, while most cells were detached in the vein grafts. The site of mechanical damage in the arterial grafts was covered by regenerated endothelial cells which showed similar morphological findings to the normal arterial endothelial cells. In contrast, regenerated cells in the vein grafts started to cover the denuded area 7 days after the implantation and had completely covered it by 3 weeks.Prostacyclin was produced more abundantly in arterial grafts than in vein grafts at any phase after implantation. The level of prostacyclin production was between 30 and 40 pg/mg in any phase after implantation of free arterial grafts, while in vein grafts the level was 2.5 pg/mg at the day of implantation and increased to 13.6pg/mg at 21 days.This study showed that the endothelial cells were well preserved and the level of prostacyclin production was high in the arterial grafts, and thus the grafts seemed to show potent anti-thrombogenicity after implantation. Although late changes in arterial and vein grafts were not investigated in this experimental protocol, these results may suggest that the arterial graft is superior to the vein graft even in the early period after its implantation as a free graft.

Use of the right gastroepiploic artery as a pedicled arterial graft for coronary revascularization.

Between April 1988 and August 1991, the right gastroepiploic artery (RGEA) was used as a pedicled arterial graft for coronary arterial bypass grafting (CABG) in 44 patients. Their ages ranged from 8 to 72 years (mean: 58.7 years), and body size was small for 21 patients (body surface area < 1.6 m2). The mean number of distal anastomoses was 3.2 +/- 0.7 per patient. The RGEA was anastomosed to the right coronary system in 35 patients and to the left in 9 patients. Perioperative vasospasm of the RGEA occurred in 4 patients, but no vasospasm was seen after intraluminal injection of diluted papaverine hydrochloride was used in the last 9 patients. The size of the RGEA at the site of anastomosis was 1.9 +/- 0.4 mm in diameter. The RGEA was harvested in 48 patients; however, two of the RGEAs were smaller than 1.0 mm in diameter and two showed severe calcification with stenosis of more than 75%. Consequently, those conduits were not used. Indications for the use of the RGEA were: relatively young age for 17, matching size of the coronary artery and the RGEA for 11, poor quality of the internal thoracic artery (ITA) or saphenous vein graft (SVG) for 10, lower leg atherosclerosis in 3, a diseased ascending aorta in 2, and Kawasaki disease in 1. The patency rate of the RGEA for 36 patients was 94.4% and relief of angina 95.5%. An exercise tolerance test performed within 2 months after operation showed improved capacity (mean 7.2 metabolic units).(ABSTRACT TRUNCATED AT 250 WORDS)