Reoperation for recurrent aortic coarctation.

BACKGROUND: Recurrence of stenosis is a complication of coarctation repair associated with major long-term morbidity. Persistent or exercise-provoked hypertension may indicate recurrent coarctation. Patients failing or not amenable to balloon dilation should be managed surgically. METHODS: A retrospective chart review was performed. RESULTS: Forty-three patients were identified as having undergone repeat surgical intervention for recurrent aortic coarctation between the years 1976 and 1993 at The Hospital for Sick Children in Toronto. Seventy percent of the children had other congenital cardiac anomalies. Eighty-six percent of patients initially treated by subclavian flap aortoplasty or end-to-end anastomosis were managed at reoperation by patch aortoplasty, and 26% of patients also required augmentation of the transverse arch (under hypothermic circulatory arrest) for accompanying hypoplasia. Three patients underwent a second reoperation; all were treated at this reoperation with tube graft interposition. CONCLUSIONS: No ischemic spinal injury occurred in patients managed with either simple proximal aortic cross-clamping or cardiopulmonary bypass. No patient treated with transverse arch augmentation required further surgical intervention. Mortality at reoperation was 7% (3 patients), similar to that of first-time coarctation repair. At follow-up (mean duration, 4.5 years), 57% of patients are normotensive, with no measurable arm-leg gradient.

Percutaneous implantation of a balloon-expandable endoprosthesis for pulmonary artery stenosis: an experimental study.

Conventional therapy to treat peripheral pulmonary artery stenosis (surgery or balloon angioplasty) has been frustrating. Recently a variety of peripheral vascular stenoses, in which conventional approaches are disappointing, have become amenable to therapy with the use of a balloon-expandable endovascular stent. This experimental study was designed to assess the application of such a prosthesis in artificially created pulmonary artery stenoses. In 9 of 12 2-week old pigs, left pulmonary artery stenosis was surgically created (3.9 +/- 1.1 mm diameter and 7 +/- 1 mm Hg mean gradient). At 6.8 +/- 1 weeks of age (13 +/- 4 kg), percutaneous (femoral venous) implantation of a 3-cm long balloon-expandable (maximal diameter 18 mm) stent (three placed into normal pulmonary artery branches) using a 3-cm x 10-mm balloon dilating catheter was achieved without technical difficulties. Stenoses were enlarged to 8.3 +/- 1.4 mm with a decrease in mean gradient to 1 +/- 1 mm Hg that was maintained through 3.5 months of follow-up. Histologic and electron micrographic studies identified normal-appearing neoendothelial layering over stent struts without intraluminal or peripheral thrombus formation and nonobstructed side branching to lung subsegments. These findings support the application of this approach in the treatment of pulmonary stenosis that is not amenable to conventional therapy.

Role of free radical scavenger in protection of spinal cord during ischemia.

Previous work in our laboratory established an experimental model for the production of paraplegia in the anesthetized normothermic adult mongrel dog. The current study involves 24 animals divided into two equal groups: Group 1 served as control, and Group 2 received treatment with scavenger agent. Vascular occlusive clamps were placed on the thoracic aorta proximal to the left subclavian artery, on the left subclavian artery at its origin, and on the distal thoracic aorta at the diaphragm for 30 minutes. In Group 1,200 ml of normal saline solution (37 degrees C) was perfused into the occluded aortic segment at the rate of 0.33 ml per kilogram of body weight per minute. In Group 2, 90% dimethyl sulfoxide (DMSO) in a dose of 0.1 gm/kg in normal saline solution (37 degrees C) for a total volume of 200 ml, was likewise injected into the occluded aortic segment at the same infusion rate. Animals were observed for evidence of paresis in the postoperative period. Microscopic analysis revealed evidence of ischemic myelopathy in the control group but none in the treated group. Under the conditions of this experiment, we conclude that the scavenger agent DMSO has a highly protective effect on the spinal cord during ischemic insult.

The effects of profound hypothermia on the cervical SEP in humans: evidence of dual generators.

Somatosensory evoked potentials recorded over Erb's point and the cervical spine (at C2 and C7) were studied in a series of children undergoing cardiopulmonary bypass surgery with hypothermia alone (n = 15) or profound hypothermia and complete circulatory arrest (n = 15). A bifid response was recorded at normothermia or mild degrees of hypothermia at both C7 (N12a, N13a) and C2 (N12b, N13b). The differential responses of these components to profound hypothermia and ischaemia suggest that N12a and N12b represent components of the same dorsal root/dorsal column travelling wave, while N13a and N13b reflect postsynaptic activities which are thought to be generated at the dorsal horn and cuneate nucleus, respectively.

Left main-stem coronary artery disease: surgical versus medical management.

The survival of surgically and medically treated patients with left main-stem coronary artery stenosis has been analysed in detail. From 1978 to 1981, 85 patients with stenosis of the left main coronary artery greater than 50% were divided into two groups; 47 were treated surgically and 38 medically. Left ventricular function, previous myocardial infarction, associated right coronary artery occlusion and extent of the left main coronary artery disease were analysed using the chi 2 and independent Student's t-tests. These important variables were comparable in both groups. Severity of angina in the two groups both pre- and postmanagement were compared using the chi 2 test and Stuart-Maxwell test. These showed that the majority of surgically treated patients improved markedly as compared with the medically treated group. Survival was examined using the Kaplan-Meier product limit estimate. The difference between the survival curves was statistically significant (p less than 0.005, generalized Wilcoxon and Savage tests), with the surgical group having the more favourable outcome. One-year and 2-year survival for the surgically treated group was 97.8% and 91.3%, compared with 79.9% and 74.9% for the medically treated group.

The cost-effectiveness of myocardial revascularization.

The formulation of a rational strategy for containing health care costs requires consideration of the cost-effectiveness of the various therapeutic alternatives available in order to assess the cost-effectiveness of myocardial revascularization in treating ischemic heart disease, the authors retrospectively analysed the costs of hospitalization and the long-term survival of 332 patients who underwent this procedure at the Victoria Hospital, London, Ontario, between 1974 and 1977. On the basis of angiographic findings the patients were divided into two groups: 51 patients who had advanced abnormalities in segmental wall motion of the left ventricle (group 1) and 281 patients who had relative preservation of left ventricular function (group 2). The presence of left ventricular dysfunction did not significantly increase the operative risk (operative mortality for group 1 v. group 2, 2.0% v. 1.8%), but showed a significant (P less than 0.01) effect on long-term survival (5-year actuarial survival rate +/- SEM for group 1 v. group 2, 74.7% +/- 9.5% v. 94.7% +/- 1.1%). Analysis of pertinent hospitalization data acquired from the Ontario Ministry of Health showed a highly significant (P less than 0.002) reduction in hospitalization expenses in the first postoperative year that continued throughout the 5-year follow-up period. The favourable effect of myocardial revascularization on long-term hospitalization costs, although evident in both groups of patients, was most marked in group 1 patients with compromised left ventricular function, as shown by the respective amortization times of costs for patients with left ventricular dysfunction, those with preserved function and for the two groups together: 22.3, 38.4 and 35.9 months postoperatively.

Aortoenteric fistula. Incidence, presentation recognition, and management.

Twenty-two patients developed one or more aortoenteric fistulae following aortic reconstruction with a dacron graft. Endoscopy was performed on 11 of these patients on 17 occasions and a preoperative diagnosis was made in eight patients. Fistulous communication was most common between the aorta and duodenum (60%), and a further 30% penetrated into the jejunum and ileum. The mean period from operation to time of diagnosis was 36 months and the mean length of bleeding was 25 days, allowing ample time for preoperative evaluation. Surgery was performed on 21 of the 22 patients with an overall mortality of 77%. The best surgical results were obtained with graft resection, closure of the aorta, and maintenance of circulation by an axillofemoral graft.

Cardioplegia for severe coronary artery disease: an improved technique using direct coronary artery infusion.

Conventional techniques of cardioplegic solution administration result in regional disparities in the level of myocardial protection in patients with severe coronary artery disease. This report describes a simple adjunct to conventional transaortic administration of cardioplegic solution, in which additional solution is introduced directly through the coronary arteriotomy used for the vein graft anastomosis. The supplemental infusate is delivered through s small-caliber flexible catheter. This technique permits effective perfusion of the coronary vascular bed distal to severely stenotic and occlusive lesions. Using an experimental model of physiologically significant coronary arterial stenosis, we compared the effectiveness of this technique with that of conventional techniques of cardioplegia.

Vancomycin blood levels during cardiac bypass surgery.

Because of the allergic reaction that some patients have to penicillin and cephalosporins, there is a need for an alternative antimicrobial agent to protect the patient who undergoes coronary artery bypass grafting from infection perioperatively. Vancomycin, a bactericidal antibiotic active against gram-positive organisms was studied in 13 men who underwent aortocoronary bypass grafting. For 60 minutes from the time the patient arrived in the operating room, vancomycin (15 mg/kg) was given intravenously. Blood levels were assayed up to 12 hours thereafter. Adequate antistaphylococcal levels of the drug were maintained throughout operation. Twelve hours later levels were subtherapeutic. There was no cardiovascular, cutaneous or renal toxicity. Two patients had minor wound infections.

Improved long-term survival following myocardial revascularization in patients with severe left ventricular dysfunction.

The natural history of patients with coronary artery disease associated with poor left ventricular (LV) function is dismal. This report analyzes the efficacy of myocardial revascularization in this subset of patients with coronary artery disease manifesting severe LV dysfunction on the basis of LV angiography, LV ejection fraction (LVEF), and left ventricular end-diastolic pressure (LVEDP). For the 2 1/2 year period ending November, 1977, 59 consecutive patients with coronary artery disease complicated by severe LV dysfunction underwent aorta-coronary bypass at the University of Western Ontario. All patients had angina refractory to medical therapy. Objective criteria for compromised LV function included the presence of three or more dysfunctional (hypokinetic of akinetic) segments on biplane LV angiography. Eighty-three percent (49/59) of patients had triple-vessel coronary artery disease. The mean LVEF for the series was 0.28 and the mean LVEDP was 18 mm Hg. The duration of follow-up was 24 to 60 months (mean 37 months), with follow-up survival data available on 100% of patients. The hospital mortality was 1.7% (1/59), and there were nine late deaths. The 5 year actuarial survival rate (+/- SEM) was 80% +/- 6%. Of the 44 long-term survivors available for direct assessment, 98% (43/44) report improvement with respect to angina and 66% (29/44) are totally asymptomatic. Eighty percent (28/35) of the long-term survivors under the age of 65 years are currently employed. These results indicate that myocardial revascularization can be performed in patients with severe ischemic LV dysfunction at very low risk and, further, that operation results in a dramatic improvement in survival expectations compared with optimal medical therapy.

Aortocoronary bypass procedures and sternotomy infections: a study of antistaphylococcal prophylaxis.

In a prospective study of cephalothin prophylaxis for patients who underwent aortocoronary bypass an unacceptably high rate (44%) of Staphylococcus aureus sternotomy infections occurred in a placebo-treated group. In two other groups of patients, one group given cephalothin intraoperatively and the other given the antibiotic both intra- and postoperatively, such infections occurred with similar frequency (2.6% and 2.1% respectively). This study demonstrates the need for antistaphylococcal agents during aortocoronary bypass operation. No advantage is derived by extending this therapy beyond the operative period.

Anomalous muscle bundle of the right ventricle. Its recognition and surgical treatment.

This communication presents our experience with 14 cases of congenital heart disease associated with anomalous muscle bundle inside the right ventricular cavity dividing it into two chambers. The clinical picture, natural history, and diagnostic characteristics are described. It can be diagnosed by right ventricular cineangiogram in the anteroposterior position. It can be resected surgically, safely.

Cephalothin Prophylaxis and valve replacement.

In a study of antibiotic prophylaxis in adults undergoing heart valve replacement, we found that a 2 gm dose of cephalothin given intraoperatively produced adequate antimicrobial activity in the bloodstream throughout the period of cardiopulmonary bypass. A dosage of 1 gm every four hours postoperatively did not lead to significant accumulation of the antibiotic. With prophylaxis restricted to the intraoperative and early postoperative period, adverse drug reactions and superinfections were not a problem. Further, no cases of prosthetic valvulitis were encountered.

The surgical repair of acute ventricular septal defect as a complication of myocardial infarction.

We advocate a classification of high and low ventricular septal defects following myocardial infarction. The natural history of the disease and the reasonable surgical results support an aggressive surgical approach in both types of septal perforation.

Prophylactic antibiotic therapy and heart valve replacement.

Patients undergoing cardiac bypass for heart valve replacement maintained adequate blood concentrations of cloxacillin throughout the duration of bypass, provided their initial blood concentration was in the therapeutic range. Blood levels related to the time between the last preoperative dose of antibiotic and operation. Maximal values were achieved if an intraoperative bolus of drug was given.

Surgical repair of acute ventricular spetal defect complicating myocardical infarction.

Ventricular septal defect complicating myocardial infarction was repaired surgically in seven patients between 1965 and 1974. In four, the septal defect had developed in the lower portion of the septum and in three, high in the septum, above the origin of the papillary muscle. Concomitant operations included mitral valve replacement and infarctectomy, in one patient, and triple aortocoronary bypass in another. The commoner low defect was repaired either by amputating the lower portion of the heart or patch-repairing through a left ventriculotomy incision. The higher defects, more difficult to repair, were repaired through a high posterior left ventriculotomy. Complete pre- and postoperative hemodynamic studies were carried out and follow-up information was available for all patients. Recognition of the high defect is essential. Pathologically, the coronary artery lesion is more complicated and extensive and a different surgical approach is necessary. A classification of high and low ventricular septal defects developing after myocardial infarction is recommeneded. The natural history of the disease and the reasonable surgical results support an active surgical approach in both types of postinfarction septal perforation.