Experimental bypass of the left ventricle.

Bypass of the left ventricle was accomplished in dogs and the entire circulation was supported temporarily by only the right ventricle. The atrial septum was excised, and the atrium was repartitioned so that the pulmonary veins were in continuity with the right ventricle and the venae cavae were connected through the atrium. Anastomosis of the superior vena cava to the right pulmonary artery brought systemic venous return directly to the lungs. The main pulmonary artery was ligated proximal to the bifurcation, preserving distal confluence of right and left pulmonary arteries. A tubular prosthesis between the proximal pulmonary artery and the aorta connected the right ventricle to the systemic circuit. This procedure, or some modification of the principle, may have clinical feasibility in the treatment of patients with hypoplastic left heart syndrome.

Hypoplastic left heart syndrome. Experience with an operation to establish functionally normal circulation.

A new operation to establish functionally normal circulation was performed in five neonates with hypoplastic left heart syndrome. With a limited period of cardiopulmonary bypass, deep hypothermia, and circulatory arrest, the patent ductus arteriosus was ligated. The atrial septum was excised and the atrium was repartitioned with a pericardial baffle so that pulmonary veins were in continuity with the tricuspid valve and right ventricle. The pulmonary artery was divided above the sinuses of Valsalva, and the proximal end was connected to the aortic arch with a tubular Dacron prosthesis. The distal end of the pulmonary artery was brought in continuity with the right atrium by way of a second Dacron conduit. The right ventricle thereby became the systemic ventricle and blood passed through the lungs vis a tergo. Circulation was supported temporarily, but all of the patients died from inadequate right ventricular performance or compromised coronary blood flow. This experience is presented to stimulate thought and some hope for babies with a uniformly fatal cardiac anomaly.

Transient cerebral ischemic attacks associated with worn porcine heterograft prosthesis. Case report.

Details are reviewed of a case of transient cerebral ischemic attacks which probably resulted from thromboembolism from a Hancock porcine heterograft prosthesis. Cause of the embolism probably was thrombus formation on the worn cloth covering of the supporting valve stent. Technical and antomic factors which assure precise seating of the prosthesis in the mitral anulus without contacting the ventricular wall appear to be important in preventing this complication.

The role of prostaglandin E in the hemodynamic response to aortic clamping and declamping.

The infrarenal aorta was occluded for one hour in 11 control dogs and in eight dogs in which biosynthesis of prostaglandin E (PGE) was inhibited by administration of indomethacin (2.5 mg. per kilogram). The mean arterial pressure (MAP) in the indomethacin group was significantly (p less than 0.001) higher than in the control group at the end of 60 minutes of aortic occlusion (187 +/- 3 vs. 137 +/- 4 mm. Hg, mean +/- S.E.M.) and remained higher (p less than 0.001) after declamping. However, the decline in MAP at the time of aortic declamping was essentially the same for both groups. Total peripheral resistance (TPR) was higher in the indomethacin group than in the control group at the end of one hour of occlusion (159 +/- 13 vs. 124 +/- 12%, p less than 0.001) and remainded higher throughout the period following occlusion. The plasma concentration of PGE in the control group increased significantly (p less than 0.05) above control (630 +/- 110 to 1,299 +/- 261 pg. per milliliter) during the 60 minute period of occlusion with further increases to 1,447 +/- 389 and 1,523 +/- 256 pg. per milliliter (p less than 0.001) at 10 and 60 seconds after declamping, respectively. In the indomethacin group, PGE remained essentially unchanged throughout the clamping and declamping period and therefore was significantly (p less than 0.05) lower than in the control group. A similar pattern was observed in the tissue levels of PGE. This study suggests that PGE is released during and after infrarenal aortic occlusion and may be responsible for maintaining reduced TPR and MAP. However, hypotension after declamping is not affected by inhibition of PGE biosynthesis.

Morbidity and mortality of coronary bypass grafting in patients 70 years of age and older.

The hospital mortality and major factors contributing to hospital morbidity and postoperative length of stay were examined in 597 consecutive patients 70 years of age and older who underwent isolated coronary artery bypass grafting (CABG) between January, 1978, and December, 1983. The mean age of the patients was 73 years, and 66% were men. Unstable angina was present in 59% of patients, left main coronary disease in 13%, and moderate or severe left ventricular dysfunction in 10%. The mean number of arteries grafted per patient was 3.4. The hospital mortality was 2.7% (16 patients) and was higher than the mortality among 4,125 patients less than 70 years of age (0.4% in 18 patients) operated on during the same interval (p less than 0.001). In multivariate regression analyses, age of 80 years or greater, evolving myocardial infarction, serious coexisting illness, major left ventricular dysfunction, emergent operation, and the development of major postoperative complications were significant (p less than 0.05) independent predictors of increased hospital mortality. Major complications occurred in 135 patients (23%). In multivariate analyses, the presence of vascular disease, serious concomitant illness, and the need for urgent or emergent operation were significant independent predictors of the development of major postoperative complications. The mean duration of postoperative hospital stay was 10.6 +/- 6 (standard deviation) days. In multivariate analyses, the development of major postoperative complications was the only variable independently predictive of prolonged hospital stay. With current techniques, CABG procedures can be safely performed in the elderly with mortality and morbidity rates only slightly higher than those in younger patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Heparin dose for accurate anticoagulation in cardiac surgery.

A simplified technique relating individual heparin dose to desired anticoagulant effect was used in 152 patients during cardiac surgery. Activated clotting time (act) was measured by semi-automated technique (Hemochron) before and after heparin, 200 U/kg I.V. Two point linear dose-response curve allowed calculation of any additional heparin required for uniform ACT of 480 seconds. Mean heparin requirement was 330 U/kg) (range 200--600 U/kg) mean requirements for adults (mean = 310 U/kg) were significantly less (p less than 0.001) than for children (mean = 430 U/kg). Individual dose-response curves suggested 20 patients (13%) could have been below adequate anticoagulant levels (ACT less than 300 seconds) using our previous formula for heparin dosage (9000 U/m2). At completion of cardiopulmonary bypass, measurement of ACT provided circulating heparin level from the dose-response curve. Protamine dose (1.3 mg/100 U. heparin) was individualized to precisely reverse anticoagulant effect to control ACT in 127 of 152 patients (84%) with a single dose. Elimination of patient and product variability by simplified semi-automated dose-response technique for heparin therapy provides uniform anticoagulant effect and its accurate neutralization. This technique is recommended for precise anticoagulant therapy during open heart surgery.

Clinical study of mitral valve repair: short-term and long-term outcomes.

BACKGROUND: In recent years, mitral valve reconstructive techniques have become an increasingly preferential alternative to replacement. The purpose of this study was to evaluate short-term and long-term outcomes associated with mitral valve repair. METHODS: This study involved 99 patients who had mitral valve repair for mitral regurgitation from January 1990 to June 1996. Short-term and long-term outcomes evaluated included mortality, clinical complications, readmissions, valve deterioration, reoperation, thromboembolism, endocarditis, functional heart class, and health perception. RESULTS: Overall mortality was 18%, which included 11 operative deaths and 7 late deaths. Ischemic valve disease and NYHA class III and IV were significant predictors of early and late mortality. Overall 5-year survival was 79%. Freedom from all valve-related morbid events was 90% at 5 years. CONCLUSIONS: Functional heart class and etiology of valve disease are the most important indicators of overall survival and morbidity. Transesophageal echocardiography should be used to evaluate the adequacy of repair.