Quantitative study of the rabbit aortic endothelium using vascular casts.

A quantitative study of the en face size and shape of rabbit endothelial cells from the ventral mid-thoracic and ventral infrarenal abdominal aorta has been carried out in 6 rabbits. Photomicrographs were taken from vascular casts of the rabbit aorta and the endothelial cell outlines were analyzed quantitatively using a digitizer and digital computer. The morphology of the endothelial cells was described using 8 calculated parameters (area, perimeter, length, width, angle of orientation, width:length ratio, axis intersection ratio and shape index). The endothelial cells in both locations had the same surface area (P greater than 0.30); however, the cells in the abdominal aorta were longer (P less than 0.01) and narrower (P less than 0.01) than those in the thoracic aorta. This fact is reflected by the smaller value for the shape index and width : length ratio in the abdominal aorta (P less than 0.01). Cells in both the thoracic and abdominal aorta were aligned with the flow direction.

Tricuspid stenosis. Atrial systolic murmur, tricuspid opening snap, and right atrial pressure pulse.

Observations on the atrial systolic murmur, the tricuspid opening snap, and the right atrial pressure pulse of tricuspid stenosis are presented, based on catheter manometer intracardiac sound and pressure recordings in five patients with hemodynamically significant tricuspid stenosis. The manometer-recorded right atrial pressure pulse of tricuspid stenosis differed from the normal, with (1) elevation of right atrial pressure, (2) different morphologic features (tall, spiky A wave complete before C; small V wave with an interruption, the tricuspid opening snap notch at termination of the gradual Y descent; a diastolic plateau, the relatively flat diastolic segment of the right atrial pressure pulse following the tricuspid opening snap notch prior to the next A wave), and (3) the relative lack of right atrial pressure and right atrial pressure pulse response with normal respiration. The atrial systolic murmur, recorded in the right ventricular inflow tract, was complete by S1; the crescendo-decrescendo atrial systolic murmur configuration paralleled the right ventricular-right atrial diastolic pressure gradient at the time of the atrial A wave. The right atrial contraction-relaxation process, as reflected by the right atrial A wave ascent and descent, was complete at the onset of ventricular systole with P-R intervals of 170 to 200 msec. Thus, the timing and configuration of the atrial systolic murmur reflected the timing and completion of the right atrial contraction-relaxation process prior to the onset of right ventricular systole and the configuration of the tricuspid diastolic pressure gradient. The tricuspid opening snap was recorded in the right ventricular inflow tract and occurred at the time of a notch at the termination of the Y descent of the right atrial pressure pulse V wave, while right atrial pressure exceeded right ventricular pressure. The sound-pressure events were consistent with angiographic and echocardiographic studies, which showed doming or ballooning of the mobile, fused, stenotic tricuspid valve into the right ventricle during the Y descent of the right atrial pressure pulse. The tricuspid opening snap occurred at the time of the termination of the diastolic movement of the fused tricuspid unit into the right ventricle. These observations are presented within the framework of previous studies in order to trace the development of medical ideas about the pathophysiologic basis for the sound and pressure events of tricuspid stenosis.

Evidence for progression from mild to severe mitral regurgitation in mitral valve prolapse.

Little information is available concerning the progression of mild to severe mitral regurgitation (MR) in patients with mitral valve prolapse (MVP). This study reports 86 patients, average age 60 years, who presented with cardiac symptoms, precordial systolic murmur, severe MR and a high incidence of MVP on echocardiography (57 of 75 [75%] ) and left ventriculography (61 of 84 [73%] ). Seventy-five surgically excised mitral valves appeared grossly enlarged and floppy. Histologic studies showed extensive myxomatous changes throughout the leaflets and chordae. Eighty patients had had precordial murmurs first described at average age 34 years, but the average age at which symptoms of cardiac dysfunction appeared was 59. However, once symptoms developed, mitral valve surgery was required within 1 year in 67 of 76 patients who had undergone surgery. Atrial fibrillation, present in 48 of 86 patients (56%), or ruptured chordae tendineae, present in 39 of 76 patients (51%), may have contributed to this rapid progression and deterioration. Additionally, 13 patients had a remote history of documented infective endocarditis. Twenty-eight patients had at least 1 type of serial clinical evaluation that indicated progressive MR in all 28 patients on the basis of changing auscultatory findings (24 of 26), progressive radiographic cardiomegaly (24 of 25), echocardiographic left atrial enlargement (4.3 to 5 cm in 11 patients) and angiographically worsening MR (14 of 15). Twenty-four of these patients had evidence of MVP on at least 1 of their initial studies. Thus, mild MR due to MVP and myxomatous mitral valves is a progressive disease in some patients with MVP.

Pulmonary sequestration.

Pulmonary sequestration is a congenital anomaly in which an aberrant systemic artery arising from the thoracic or upper abdominal aorta supplies part of the lungs, usually the lower lobe. The sequestered lung may be anatomically distinct from the remainder of the lobe (extralobar), or may be included in the substance of the lobe, in which case it may or may not have bronchial communication with the rest of the bronchial tree. The patients present, often in the first two decades of life, with recurrent and severe bronchopulmonary infections. Associated anomalies are present, especially in the extralobar variety. Nine cases of sequestration are reviewed, stressing significant clinical, radiological, and arteriographic findings. Preoperative demonstration of the anomalous vessel by aortography has contributed significantly to the planning and safety of the surgical procedure, which was generally a lower lobectomy. Eight out of nine patients survived the procedure.

Congenital mitral stenosis.

This report presents a 15 year review of the surgical treatment of 9 patients with congenital mitral stenosis seen at the Columbus Children's Hospital. The over-all mortality rate was 45 per cent. Seven patients had associated lesions, mostly coarctation of the aorta and patent ductus arteriosus. In the planning of the operative procedure, distal obstructive lesions of the left heart should generally be relieved first. The mitral valve should be explored with the use of cardiopulmonary bypass and the anatomic type of the valve determined. Type I valves will often respond to open valvulotomy, whereas Type II and III valves must be replaced.

Open lung biopsy. Its effects on therapy in the pediatric patient.

The records of 35 pediatric patients who had open lung biopsies at Columbus Children's Hospital, Columbus, Ohio, were analyzed to determine the results and the effects on therapy. Twenty-two (63 percent) of these patients were immunocompromised, and they are compared to the non-compromised group. A diagnosis was obtained in all cases. An infectious agent was identified in 13 (37 percent) of the patients. Ten of these were immunocompromised. In 43 percent (15 patients) of the total group and 55 percent (12 patients) of the immunocompromised group, the results of the biopsy effected a change in therapy. Five patients died, all of whom were immunosuppressed. None died as a direct result of the open lung biopsy. The total morbidity rate was 23 percent (eight patients). We concluded that open lung biopsy can be accomplished safely in the pediatric patient and that the results affect the therapeutic decision-making process a significant portion of the time.

Results of operation for aortic valve stenosis in infants, children, and adolescents.

Surgical procedures for aortic valve stenosis may be considered either corrective or palliative. During a 22-year period from 1962 to 1984, 120 patients required operation for aortic valve stenosis. The operations done included 117 valvotomies and three initial valve replacements. Six patients, five infants and a 7-year-old girl, died at operation. The remaining 114 patients were followed up for 1 to 23 years (mean 8.7 years). Twenty-six patients (23%) required a second operation 1 to 15 years (mean 6.8 years) after initial valvotomy. Six patients (5%) required a third operation 3 months to 8 years (mean 4.4 years) after the second operation. Eighteen of the 26 patients (69%) having second operations required valve replacement. All third operations were valve replacements. No perioperative deaths occurred at the second and third operations. There were four sudden late deaths (3.5%). Eighty-four of the 114 patients (74%) followed up for 1 to 23 years (mean 7.7 years) have had a satisfactory result from initial valvotomy, being free of symptoms and major events (stroke, endocarditis, sudden death), and have not required reoperation. Fifty-nine percent of a subgroup of 22 patients followed up for a mean of 17.7 years have had a satisfactory result from initial valvotomy.

Reasonable surgery for thoracic neuroblastoma in infants and children.

Neuroblastoma is the most commonly encountered soft tissue malignant tumor of childhood. Over the past 30 years we have treated 180 patients with neuroblastoma. Sixty-five percent had primary abdominal tumors and 20 percent (41 patients) had primary chest tumors. For the 22 patients under the age of 2 years, the 2 year survival rate was 87 percent. There were 19 patients who were 2 years of age or older, and of these only seven patients have survived 2 years after the diagnosis was made. The vast majority of these patients were treated with surgery (debulking type procedure) and postoperative radiation and chemotherapy. Patients with the most differentiated tumors had a remarkably good survival rate, with no deaths. However, the tumors with lesser differentiation did not stratify enough focus to draw conclusions as to survival. Staging correlated the least with survival when compared to age or grading. The 2 year survival rates for patients with Stage I, II, III, IV, and IV-S disease were 75, 82, 100, 17, and 80 percent, respectively. In conclusion, 41 cases of documented primary thoracic neuroblastoma are reviewed, with follow-up from 2 to 27 years (average 9.3 years). We have concluded from this experience that age is the main determining factor influencing survival. Heroic and/or radical surgery is contraindicated in this disease.

Late failure of porcine valve heterografts in children.

Heterograft porcine valves have gained wide acceptance in replacement of diseased cardiac valves, and their clinical performance in adults has been very satisfactory over follow-up periods of up to 8 years. Valve replacement in children is relatively infrequent and experience with porcine xenografts is necessarily small. Our combined experience at three university hospitals has been with 25 children, 17 months to 16 years of age, who have been followed for 10 to 54 months (mean follow-up 33 months). Porcine valves were used to replace the aortic valve in nine, the mitral valve in seven, both valves in two, the tricuspid valve in two, and the pulmonary valve in five patients. Severe bioprosthetic valve dysfunction has occurred in five (20%) of these patients so far and necessitated replacement because of severe stenosis in mitral (two) or aortic (three) valve prostheses at 18 to 45 months after implantation; one postoperative death occurred among the five reoperations. Pathological examination showed extensive fragmentation of collagen with focal heavy calcification and degeneration. In addition we have encountered deterioration and calcification of two porcine valves in 23 valved conduits followed for 12 to 70 months (mean 43 months), requiring removal and replacement of the valves 65 and 67 months after implantation. This experience indicates a disquietingly high incidence of relatively early failure of porcine xenograft valves in children. This is significantly higher than the failure rate observed in adult patients. The failure rate is not consistently related to the small size of an implanted valve which becomes relatively narrow with the growth of the patient, leading to excessive turbulence and trauma to the prosthesis. Other factors, including increased turnover of calcium and accelerated rejection in growing children, may contribute to these failures and should be examined in order to improve long-term results. A satisfactory performance would make heterografts the ideal valvular prosthesis in children, since anticoagulation is avoided.

Independent preclerkship study: a five year experience.

An independent study program (ISP) was instituted in 1970 for a group of 32 preclerkship medical students picked randomly from a group of 64 volunteers. The academic achievements of these classes, as measured by mean National Board scores, is compared with their classmates in the lecture discussion (LD) program where possible. The significant differences noted obtain even when the ISP students are compared only with LD students matched for premedical point-hour ratios and Medical College Admissions Test scores. These data attest to the overall success of the ISP program. The differences appear to us to be due mainly to factors related to motivation and maturity. The ease of preparations, convenience, and economy of the associated computer-assisted instruction make these methods attractive for use in residency training and continuing medical education where maturity and motivation may well be presumed.

Effects of pharmacological myocardial depression on coronary artery collateral formation.

Treatment of angina pectoris falls within two spheres: (1) increasing myocardial blood flow (direct bypass, vasodilators), or (2) reducing oxygen demand (beta blockade, propranolol). If the latter depresses the stimulus for collateralization without improving input, its use in certain forms of coronary disease may require reconsideration. To examine this hypothesis, 25 dogs (four groups) were evaluated by surface mapping, angiographic collateral mapping, and hemodynamic studies including cardiac output, systemic and coronary pressures, coronary flow, and left ventricular end-diastolic pressure, pressure to time (LVdp/dt). Collateralization was induced with ameroid constrictor placement in Groups I, III, and IV. Groups II and III received immediate propranolol treatment (3 to 5 mg. per kilogram per day for 6 weeks); Group IV received delayed treatment (4 weeks after constriction); and Group I received no propranolol (constrictor alone). Collateral formation was depressed significantly in the acutely beta-blockaded dogs (Group III) by surface and angiographic mapping and by hemodynamic evidence of depressed coronary flow and altered coronary retrograde pressures. Alterations in established collaterals (Group IV) were not consistent. These data suggest that pharmacological reduction of myocardial oxygen demand reduces coronary collateralization experimentally, requiring further evaluation of its usage in multivessel coronary disease to the exclusion of direct bypass.

Nonpenetrating trauma to the thoracic aorta.

Twenty-seven patients underwent surgical repair for nonpenetrating injuries of the thoracic aorta. Emergency operation was performed in 19 patients with acute aortic injury and there were 12 survivors. Left heart bypass (LHB), external shunts, and simple aortic cross-clamping were methods employed during repair. All operative deaths occurred in the left heart bypass group. Morbidity, hospital stay, operative time, and blood loss all were markedly less in patients repaired with an external shunt or simple cross-clamping. Systemic heparinization related adversely to mortality and morbidity. Eight patients had repair of chronic post-traumatic descending aortic aneurysms. One of these had previous repair elsewhere with paraplegia and subsequent mycotic aneurysm at the graft repair site. He presented to us with massive hemoptysis. Surgical correction in the chronic group was performed using either left heart bypass, external shunt, or simple aortic cross-clamp with graft interposition. The only death occurred in a patient repaired on left heart bypass.

Pulmonary resections in children: problems and precautions.

Forty-eight pulmonary resections were performed in 45 children. The principal indications for operation were bronchiectasis, congenital cysts, and lobar emphysema. Nine complications occurred in five children. There were three deaths, a mortality of 6.7%. While resection can be performed safely in most children, a high-risk group is identified as those with severe congenital cardiopulmonary disease complicated by chronic or recurrent infection.

Combined median sternotomy and posterior lateral thoracotomy: a method for proximal and distal thoracic aortic exposure.

A method for exposure of the heart, ascending aorta, aortic arch vessels, and descending thoracic aorta in a single surgical field is presented. Five illustrative cases are reviewed. Indications for use include trauma to the aorta and arch vessels, aneurysms or dissections, ductus aneurysms, or complex or secondary coarctations of the aorta.

Delayed sternal closure after cardiac surgery.

Fifty-seven patients undergoing various cardiac operations were managed with delayed sternal closure because of ongoing mediastinal hemorrhage or extreme cardiac dilatation. This strategy facilitated rapid access to the mediastinum for evacuation of clot when the risk of tamponade from hemorrhage was deemed great. When sternal closure over a dilated and edematous heart caused hemodynamically significant cardiac compression, wound closure without sternal reapproximation facilitated hemodynamic stability. Postoperative correction of hemodynamic and hemostatic functions allowed delayed sternal closure to be done a mean of 2.8 days later. Thirty-eight patients survived to leave the hospital. Recognized complications of delayed sternal closure included superficial wound infection (3 patients), sternal osteomyelitis (1 patient), and fatal mediastinal infection (1 patient). Delayed sternal closure may be beneficial in selected patients. Morbidity and mortality related to this technique have proved acceptable in this high-risk group.

Simplified management of chylothorax in neonates and infants.

A simplified method for managing chylothorax in neonates and infants is presented. Use of an elemental diet markedly reduces the volume of the chyle leak while supporting total caloric intake. Either prolonged drainage or reexploration often can be avoided by the use of the described regimen.

Pharmacological blood pressure reduction as an adjunct in the operation for patent ductus arteriosus.

In some patients with patent ductus arteriosus, it is especially difficult to obtain an adequate length of the ductus for its safe division. In these patients, additional length can be obtained by pharmacological reduction of the blood pressure with sodium nitroprusside. The management of 2 such patients is reported.

Pedunculated left ventricular rhabdomyoma.

A patient with an unusual left ventricular outflow tract obstruction caused by a solitary pedunculated left ventricular rhabdomyoma is described. Diagnosis was based on two-dimensional echocardiographic findings alone. The obstructive portion of the tumor was successfully removed from the interventricular septum by an aortic root approach.

Counterpulsation catheter fracture: an unexpected hazard.

This paper presents a previously unrecognized hazard associated with intraaortic balloon pumping: fracture of the catheter due to chemical damage by acetone at the time of removal. Common hospital chemicals such as acetone, ether, and Vi-Drape spray may damage the catheter. Contact between these agents and polyurethane intraaortic balloon catheters should be avoided during dressing changes or repreparation of a sterile operative field. Isopropyl alcohol, Betadine, benzoin, and Cidex do not damage the catheter.

Coronary artery fistula in the pediatric age group: a 19-year institutional experience.

Ten patients with coronary artery fistulae were identified from records at Columbus Children's Hospital between 1974 and 1993. Clinical presentations of patients were quite variable, from 1 day to 20 years of age. Symptoms ranged from none to severe cardiorespiratory failure requiring extracorporeal membrane oxygenation. Long term follow-up revealed one sudden death and one spontaneous closure of the fistula. This lesion should be ruled out in patients who present as extracorporeal membrane oxygenation candidates. Patients with mild forms of this lesion may be followed up medically if the left to right shunt is inconsequential, because spontaneous closure is a possibility. Because of the risk of sudden death, close long-term follow-up is mandatory even for operated patients, and antiplatelet therapy should be considered for these patients.