Emergency palliation of critical valvular aortic stenosis. A new application of prostaglandin E1

Aortic stenosis: the spectrum of practice

There is significant variation in practice patterns in managing congenital aortic valve stenosis. Review of medical literature reveals no significant information regarding the current practice methods in the treatment of a simple lesion such as aortic stenosis (AS). Therefore, this survey-based study was conducted in an attempt to better understand the uniformity or heterogeneity of practice in treating AS. A questionnaire was prepared to evaluate the style of management of AS. This survey was designed to assess the practice of follow-up visitations, type and frequency of investigative studies, pharmacological therapy, and exercise recommendations. Questions about therapeutic intervention included those of timing and type of intervention. Questionnaires were sent to all academic pediatric cardiology programs in the United States (48 program) and selected international programs from Europe, Asia, and Australasia (19 program). The total number of surveys sent out was 67, and the total number of respondents was 25 (37%), 15 (31%) from the United States and 9 (53%) from outside the United States. The definition of moderate AS varied among respondents. The range provided for mild AS was identified as that with a peak-to-peak pressure gradient of < 25-30 mmHg, peak instantaneous Doppler gradient of < 36-50 mmHg, or mean Doppler gradient of < 25-40 mmHg. On the other hand, severe AS was defined as that with a peak-to-peak gradient of > 50-60 mmHg, peak instantaneous Doppler gradient of > 64-80 mmHg, or mean Doppler gradient of > 45-64 mmHg. In assessing follow-up patterns, 84% of respondents recommended seeing patients with mild AS annually, the longest time of follow-up listed in the questionnaire, whereas 20% suggested follow-up every 6 months. There was no consensus among survey centers regarding follow-up of patients with moderate AS. For severe AS, 16% recommend immediate intervention, 16% arrange follow-up every 6 months, and 56 and 28% recommend follow-up in 3 and 1 month(s), respectively. In making the decision to proceed with biventricular versus univentricular repair in patients with AS in the neonatal period, many factors were considered. Ninety-two percent of respondents rely on mitral valve z score, 84% on aortic valve z score, 52% on left ventricle length, 48% on the presence of antegrade ascending aorta flow, and only 32% considered significant endocardial fibroelastosis as a factor. Rhodes score was used by 20% of respondents in decision making regarding the approach to management of this subset of AS. This study shows that there is consensus in the management of mild and severe forms of AS. As expected, disagreement is present in the definition, evaluation, and therapy of moderate aortic valve stenosis. There is a tendency for catheter intervention except in the presence of dysplastic aortic valve or moderate to severe aortic regurgitation. There is also disagreement regarding methods used to determine biventricular versus univentricular repair of a borderline hypoplastic left heart.

Pre- and Postoperative Quantitation of Right Ventricular Tissue Doppler Velocities in Infants with Hypoplastic Left Heart Syndrome

BACKGROUND

The purpose of this study was to use tissue Doppler imaging (TDI) to serially quantitate initial and preoperative right ventricular (RV) TDI velocities and compare them to postoperative RV TDI velocities as measures of RV function in newborns with hypoplastic left heart syndrome (HLHS).

METHODS

Twelve consecutive patients were prospectively studied with diagnosis of HLHS. Systolic (Sw) and early diastolic (Ew) velocities were recorded at the tricuspid annulus and the ventricular septum at (1) admission, (2) immediately preoperative, and (3) during recovery. All patients were treated preoperatively with prostaglandins (PGE). Velocities were compared using repeated measure analysis of variance.

RESULTS

Mean age at diagnosis was 1 day (0-4 days). Time from diagnosis to surgery was 4 days (1-9 days), age at surgery 5.3 days (2-10 days), and time from surgery to postoperative echo 12.3 days (5-19 days). Tricuspid annular and septal systolic velocities increased from admission to preoperative. Both tricuspid Sw and Ew and septal Sw velocities decreased postoperatively. No significant changes occurred in the ventricular septal diastolic (Ew) velocities from admission to preoperative.

CONCLUSION

These data indicate that following the institution of PGE and initial medical and ventilatory management, there is an increase in RV annular and septal systolic velocities from the initial to the preoperative period and that these indices as well as RV annular diastolic velocities decline significantly postoperatively. Initial septal diastolic velocities were severely abnormal and did not significantly change pre- and postoperatively. These data may have significance for both postoperative and subsequent long-term RV function.

The prognostic value of intraoperative pressure gradients with congenital aortic stenosis

Patients with congenital aortic stenosis are subject to sudden death without prior symptoms. Indications for operation are based on pressure gradients, but intraoperative evaluation of results after relief of obstruction can be subjective and arbitrary. Between September, 1981, and October, 1983, 21 patients underwent operation for relief of congenital aortic stenosis. Fifteen had valvular, 4 had supravalvular, and 2 had subvalvular stenosis. Seven patients were 1 year of age or younger, 2 being 3 days old. Preoperative inotropic support and emergency operation were necessary in 2 patients. Intraoperative pressure gradients were measured in all but the 2 patients who were 3 days old. All patients survived without complications. Intraoperative and postoperative pressure gradients were available in 16 patients. The average preoperative pressure gradient was 76 mm Hg. It was significantly lowered to 20 mm Hg (p less than 0.001) intraoperatively, which compared with 15 mm Hg postoperatively. Three patients had an unsatisfactorily high intraoperative pressure gradient after initial intervention. Immediate reexploration and incision of the rudimentary commissure in 2 and excision of redundant valvular tissue in the other resulted in a more satisfactory pressure gradient without substantial aortic insufficiency. We suggest that measurement of intraoperative pressure gradients can accurately assess the results of therapy and allow the surgeon the option of reexploration for further intervention. Moreover, the high correlation between intraoperative and postoperative pressure gradients can help in planning postoperative management and future cardiac catheterizations.