William F. Bernhard

Interrupted aortic arch: Surgical treatment☆

Abstract A new palliative surgical procedure for interruption of the aortic arch was successfully performed in an infant. A Teflon graft was inserted from the main pulmonary artery to the descending thoracic aorta in order to bypass a stenotic ductus arteriosus, and both pulmonary artery branches were banded to reduce the pulmonary blood flow. This procedure may also prove life-saving in the hypoplastic left heart syndrome, with the addition of atrial septal defect creation when left atrial decompression is indicated. This syndrome was the commonest cause of death from congenital heart disease in the first month of life in our recent experience (31 percent), based on a consecutive autopsy series of 174 neonates with congenital heart disease. The anatomic findings in 10 autopsy cases of interrupted aortic arch are summarized. A new understanding of the morphogenesis of these anomalies is presented, based on correlation of embryologic and pathologic data. The literature on interruptions of the aortic arch is reviewed, and surgical experience with these malformations is considered in detail.

Fixed subaortic stenosis in the young: Medical and surgical course in 83 patients

Eighty-three patients aged 11 months to 25 years were followed up a median of 6.1 years (range 8 days to 24 years) after diagnosis of fixed subaortic stenosis (SAS). Fourteen (17%) had significant noncardiac defects and 47 (57%) had additional cardiac malformations. The left ventricular (LV) outflow gradient increased in 25 of 26 patients catheterized more than once before surgery. Of 15 patients less than 12 years old with gradients less than or equal to 40 mm Hg, 10 ultimately underwent operation after developing severe obstruction; another has progressed to a gradient of 45 mm Hg at 6 years of age. Before surgery (at a median age of 12 years), 55% had aortic regurgitation (AR), which was usually mild. Infective endocarditis occurred in 12% of the group, with a frequency of 14.3 cases per 1,000 patient-years. Seventy-four patients were operated on, with 6 early (8%) and 7 late (9%) deaths. Twelve underwent reoperation to relieve residual obstruction. Surgery reduced gradients in patients with discrete SAS from 83 +/- 33 to 29 +/- 30 mm Hg, but in 6 patients with tunnel SAS the reduction was less satisfactory. AR was absent or mild in most patients postoperatively. When the gradient was reduced to less than 80 mm Hg, infective endocarditis did not occur unless there were other residual lesions. These data suggest that it is reasonable to resect discrete SAS in children less than 10 to 12 years old with LV outflow gradients greater than or equal to 30 mm Hg.

Results of routine preoperative coronary angiography in tetralogy of Fallot.

In the surgical repair of tetralogy of Fallot, morvidity and mortality are increased by certain coronary anomalies, in particular, an anterior descending branch originating from the right coronary artery or a single coronary artery in which a large coronary branch runs across the pulmonary outflow tract. In series of 94 patients with tetralogy of Fallot who underwent cardiac catheterization, coronary artery visualization was attempted routinely, most often by flush aortography using a venous catheter. Diagnostic coronary visualization was obtained in 84 patients (89%). In these, the incidence of recognized coronary anomalies was 5%; anterior decending from the right coronary artery in four patients (4%), and singly left coronary in one patient (1%). In 195 autopsied cases of tetralogy, the incidence of coronary anomalies was also 5%. Routine preoperative demonstration of the coronary artery anatomy in tetralogy patients usually can be accomplished satisfactorily and conveniently by transvenous flush aortography.

Congenital mitral stenosis. A review of 20 years' experience.

The clinical course of 38 patients with congenital mitral stenosis (MS) is reviewed. Associated cardiac defects were present in 28 patients, including tetralogy of Fallot in five. In all but one of the eight patients with supravalvar mitral ring (SVR), there were concomitant abnormalities of the mitral valve. Delay in the diagnosis of MS was common. Serial cardiac catheterizations and pulmonary pathologic examination indicated that pulmonary vascular obstructive disease develops during childhood. Mitral valve surgery was performed in 19 of 38 patients: valvotomy alone in eight, excision of SVR in five (two of whom also had valvotomy) and mitral valve replacement in seven. Additional non-mitral cardiac surgery was performed in 18 patients. Overall surgical mortality was 49%percnt;; mortality for surgery on the mitral valve was 26%percnt;. Only patients having mitral valve replacement or with isolated SVR which was then resected became asymptomatic and had normal hemodynamics on postoperative catheterization.

Temporary left ventricular bypass: factors affecting patient survival.

SUMMARY Circulatory support (range, 2 hours-8 days) was undertaken in eight cardiac surgical patients (with two survivors) exhibiting intractable cardiogenic shock. A paracorporeal, pneumatic, xenograft-valve pump was interposed between the left ventricular apex and ascending aorta. Pumping lowered left atrial and ventricular pressure while maintaining cardiac output (1.8-2.6 I/min/M2). Following implantation, plasma hemoglobin and erythrocyte mechanical fragility values were elevated but decreased to normal when renal function was not impaired. Mild thrombocytopenia was noted in three patients and was severe in five others with persistent hemorrhage. Anticoagulation agents were used during tapering of pump flow (three patients) after 100, 105 and 120 hours of bypass. Otherwise, for the major portion of the interval of mechanical circulatory support, anticoagulants were not administered. Despite this fact, no systemic embolization was detected in any of the patients. It appears that assist pump support can be life-saving in acute left ventricular failure in patients following cardiac surgery.

Experience with Valved Conduits for Repair of Congenital Cardiac Lesions

Dacron valved conduits or aortic allografts were placed between the right heart and the pulmonary artery for repair of various complex congenital cardiac anomalies in 56 patients (aged 15 days to 33 years; median, 11 years). Forty-four patients had a total of 56 previous palliative procedures, which contributed to postoperative morbidity and mortality. Six patients had a total of seven episodes of early or late sepsis involving the conduit. One patient, treated for early sepsis, again developed infection in the Hancock graft 1 year postoperatively and died. Three other patients, 2 with calcified allografts, developed infections 4 months to 7 years following repair and required graft replacement. Hemodynamic data 1 month to 5 years (mean, 1.6 years) following repair revealed mild to moderate obstruction (less than 45 mm Hg gradient) at the Hancock conduit valve ring in 13 of 19 patients, while 5 had large pressure gradients (greater than 75 mm Hg). All aortic allografts had severe obstruction and calcification necessitating graft replacement. It is anticipated that improved technique and appropriate timing of palliative and corrective operations will substantially reduce or eliminate these problems.

The surgical management of discrete and diffuse supravalvar aortic stenosis.

Between 1956 and 1976, 18 patients underwent surgery for supravalvar aortic stenosis at The Childrens Hospital Medical Center, Boston. Discrete obstruction, present in 11, was treated by insertion of a prosthetic gusset placed across the area of narrowing and extending into the noncoronary sinus of Valsalva. There was one operative death. Residual gradients (measured in five patients) ranged from 4–55 mm Hg, one of which was supravalvar in location. Significant aortic regurgitation was not common preoperatively. The diffuse form of supravalvar obstruction, a more difficult surgical problem, was present in seven patients. There were three operative deaths. Complete relief of the pressure gradient was achieved only in one instance by insertion of a left ventricular-aortic bypass shunt diverting the majority of the cardiac output into the descending thoracic aorta. This patient is now asymptomatic 20 months following operation. On the basis of this experience, it is suggested that patients with the diffuse form of supravalvar obstruction, and perhaps even those with a hypoplastic annulus alone, would benefit from a left ventricular-aortic bypass shunt.

Long-term follow-up of valvotomy before 1968 for congenital aortic stenosis

The clinical course of 59 patients who underwent valvotomy for aortic stenosis before 1968 was reviewed. All were older than 1 year at the time of operation. Mean follow-up period was 17.7 years. Forty-six patients are alive; 26 (57%) are 30 to 40 years and 6 (13%) are older. Actuarial analysis indicated that the probability of survival was 94% at 5 years and 77% at 22 years. Thirteen patients died, 7 suddenly. Among the latter, significant obstruction or regurgitation was present in the 4 who underwent catheterization 0.9 to 7.2 years before death, 2 of whom were symptomatic and 2 with progression of a strain pattern on electrocardiogram. Surgery was recommended but declined by the latter 2 patients. Reoperation was carried out in 21 patients (36%), 3 (12%) of whom died. Actuarial analysis revealed the probability of reoperation to increase from 2% at 5 years to 44% at 22 years. Bacterial endocarditis occurred on 4 occasions in 3 patients, 1 of whom died suddenly during treatment. The incidence of endocarditis was 3.8 episodes/1,000 patient-years. Actuarial analysis of serious events, defined as death, reoperation and endocarditis, with the most serious of these and each patient being represented only once, indicated the probability of being free of such an episode to be 92% at 5 years, decreasing to 39% at 22 years. These data emphasize the palliative nature of valvotomy and the meticulous follow-up so necessary in these patients.

PULMONARY ARTERY BANDING: INDICATIONS AND RESULTS IN INFANTS AND CHILDREN.

BANDING of the pulmonary artery has been proposed as a therapeutic procedure for patients with a large left-to-right shunt and pulmonary artery hypertension not amenable to complete correction. It was theorized that by increasing the resistance to outflow from the right ventricle, and thus lowering the pulmonary artery pressure, the size of the left-to-right shunt would diminish, the high output failure state would improve, and the pulmonary arterioles might be protected from developing progressive intimal changes. The original proposal by Muller and Dammann was reported in 1952,1 at a time when surgery with the pump oxygenator was not available. It had been assumed that, with the introduction of cardiopulmonary bypass, this palliative procedure would be outmoded and discarded, and all left-to-right shunts would be repaired in a one-step open-heart procedure.2 The experiences of the past few years have demonstrated, at least to us, that despite the technical progress, the pulmonary artery banding procedure is still applicable in patients who have a ventricular septal defect under these specific situations: (1) young infants with large left-to-right shunts and intractable congestive heart failure who are too small to be operated upon by means of cardiopulmonary bypass; (2) children with left-to-right shunts and severe obstructive pul-

Diagnosis and Surgical Treatment of Infants with Critical Pulmonary Outflow Obstruction Study of Thirty-four Infants with Pulmonary Stenosis or Atresia, and Intact Ventricular Septum

The records of 15 infants with pulmonary atresia and 19 infants with critical pulmonic stenosis and intact ventricular septum, all under 1 year of age, have been reviewed. Symptoms started earlier and were more severe in the group with pulmonary atresia. All patients showed arterial unsaturation, and many had congestive heart failure The electrocardiogram was the most helpful tool in differentiating pulmonary atresia from pulmonic stenosis with intact ventricular septum. The presence of P pulmonale, significant right axis deviation, and right ventricular hypertrophy favors pulmonic stenosis. At cardiac catheterization, patients belonging to both groups showed right ventricular hypertension of significant degree, but this was more marked in infants with pulmonic stenosis. Results of surgery for pulmonary atresia with intact ventricular septum, by a variety of methods, have been uniformly poor up to the present. Direct attack on the pulmonary outflow tract, when possible, may offer more promise for the future. Pulmonary valvotomy is the operation of choice for pulmonic stenosis and the results are good.