OLGA I. SHINDLER MD, ALAN K. TANNENBAUM MD, DANIEL M. SHINDLER MD.
Reproduced by permission from Primary Cardiology July, 1995.
We present four adults with pulmonic stenosis who underwent echocardiographic evaluation in our laboratory. They present a wide genetic spectrum, diverse diagnostic findings, as well as varied therapeutic options.
CASE 1
A 53 year old man was referred for echocardiography due to progressive symptoms of shortness of breath on exertion. He was not followed regularly by a physician. The referral for echocardiography was prompted by his symptoms as well as by a systolic murmur best heard at the left upper sternal border. There was no history of cyanosis.
The resolution of the transthoracic echocardiogram was poor. However it was still possible to perform a pulsed wave Doppler examination from the short axis parasternal view. Pulsed wave Doppler identified systolic blood flow acceleration at the level of the pulmonic valve. Flow velocities in the right ventricular outflow were normal. The peripheral pulmonary artery velocities were not obtainable. Continuous wave Doppler examination revealed a peak gradient of 85 mm Hg.
The patient was referred for cardiac catheterization. There was, indeed, a gradient across the pulmonic valve but an additional unexpected finding was a step up in right atrial oxygen saturation indicating the presence of an atrial septal defect. The patient was then referred for transesophageal echocardiography. This confirmed the presence of a large non restrictive secundum atrial septal defect. (fig 1 and 2) He underwent open heart surgery to close the defect and to perform open pulmonary valvotomy (1) to relieve the stenosis. The coronary arteries were normal.
His postoperative course was complicated by atrial tachyarrhythmias. After those resolved he was once again lost to follow up, despite numerous requests to him to go to a physician on a regular basis.
CASE 2
A 72 year old female was referred for echocardiography to follow up a previous diagnosis of pulmonic stenosis made on cardiac catheterization 5 years before. Echocardiographic examination confirmed the presence of valvular pulmonic stenosis. There was right ventricular hypertrophy. The atrial septum bulged toward the left atrium indicating that the right atrial pressures were higher than left atrial pressures. There was no contrast evidence of an atrial septal defect. The contrast examination was performed with agitated saline during transthoracic imaging and the patient was asked to cough vigorously. There was no evident contrast in the left atrium with this technique. Next, albunex was injected, completely opacifying the right atrium. There was no evident negative contrast effect. The gradient across the pulmonic valve was 64 mm Hg - manifested as a 4 meter per second peak velocity in the pulmonary artery. The pulmonic leaflets exhibited doming (indicative of commisural fusion) without increased thickening (dysplasia) making her a candidate for catheter balloon valvuloplasty.(2)
CASE 3
A 35 year old female with Prader-Willi Syndrome was found to have a 31 mm Hg gradient across her pulmonic valve. Prader-Willi Syndrome is a multisystem disorder consisting of hypotonia, hypomentia, hypogonadism and obesity with a tendency to diabetes mellitus. Pulmonic stenosis is not part of the syndrome. The referral for echocardiography was prompted by a complaint of dyspnea.
There was also tricuspid insufficiency with a peak velocity of 4.2 meters per second, indicating a right ventricular systolic pressure of 81 mm Hg. This meant that 40 mm Hg of the right ventricular peak systolic pressure was not due to valvular pulmonic stenosis. The patient refused transesophageal echocardiography to look for peripheral pulmonary artery stenosis. A tentative diagnosis was made: valvular pulmonic stenosis combined with increased pulmonary artery systolic pressure, explaining the discrepancy between the mild valvular pulmonic stenosis and the significant right ventricular systolic pressure overload. She is being followed with yearly transthoracic echocardiograms to assess right ventricular function.
CASE 4
A 27 year old male with a history of surgical repair of a congenital heart defect at age 7 was referred for a baseline echocardiogram. He did not know the nature of his cardiac surgery. Transthoracic echocardiography revealed a dilated right atrium and hypertrophied right ventricle. The atrial septal orientation was normal. There were no areas of increased echogenicity to indicate a patch or sutures in the atrial septum. There was a 19 mm Hg gradient across the pulmonic valve. The leaflets did not appear thickened. The right ventricular outflow was dilated. The peripheral pulmonary artery flow velocities were normal. It was only when he stood up to get dressed after the echocardiogram that he was noted to have ptosis, webbed neck, low set ears, and scoliosis: Noonan's syndrome.(3)
DISCUSSION
These four cases illustrate the spectrum of pulmonic stenosis in adults. The adult cardiologist can indeed, encounter occasional patients with varying degrees of pulmonic stenosis.(4) It is important to recognize that right ventricular outflow obstruction may also be due to peripheral pulmonary artery stenosis as well as valvular and\or infundibular stenosis.
The transthoracic echocardiographic examination in the adult can be fraught with technical difficulties. There may be difficulty in obtaining high quality images of the interatrial septum in these patients. It is quite difficult to visualize all three pulmonic leaflets. M-mode remains valuable in this case to depict leaflet thickness and motion. There are often unanswered questions and on occasion actual misdiagnosis when only transthoracic images are employed.
Transesophageal echocardiography is a valuable adjunct to visualize the pulmonic leaflets easily answering the question whether they are too thick and dysplastic for a successful balloon valvuloplasty. The right ventricular outflow can be scanned tomographically by slowly pulling back the probe in the esophagus. The main pulmonary artery can be accurately measured for poststenotic dilatation. The pulmonary artery bifurcation can be inspected for peripheral stenosis.
Contrast is useful for demonstrating an associated atrial septal defect. It is preferable to first employ contrast during the initial transthoracic evaluation rather than postpone it until the transesophageal study. It is much more comfortable and effective for a patient to cough and perform Valsalva maneuvers to increase the right sided pressures (provoking a transient right to left shunt).(5) Skipping this in the first patient resulted in a missed diagnosis of a large atrial septal defect. We think it also made him lose any faith he had in our diagnostic capabilities. Color Doppler flow is less reliable than contrast since the elevated right atrial pressures tend to match the left atrial pressures with little, if any, Doppler evidence of flow acceleration across the defect.
Pulmonic stenosis can be associated with other congenital heart defects. Patients with Noonan's syndrome (case 4) characteristically have thick, dysplastic pulmonic valves with an associated atrial septal defect. Interestingly, the literature on case 3: Prader-Willi Syndrome, also a genetic defect,(6) does not suggest an association with pulmonic stenosis.
The right ventricle responds with hypertrophy to the pressure overload of pulmonic stenosis. Doppler evaluation is quite useful in assessing right heart hemodynamics.(7) Tricuspid insufficiency is fortunately (for this purpose), present in many patients, allowing estimation of the right ventricular systolic pressure. Tricuspid insufficiency can be further enhanced with contrast to provide a stronger signal and possibly more accurate estimation of the peak velocity. A discrepancy between the tricuspid insufficiency velocity and the pulmonic stenosis gradient should alert one to the presence of combined abnormalities. In the newborn, pulmonic stenosis can be combined with transient pulmonary hypertension. Later however, pulmonic stenosis actually protects the pulmonary vasculature when right heart pressure or volume overload is present. As patients grow to adulthood they can develop mitral insufficiency and possibly once again, pulmonary hypertension by this mechanism. Both acute and chronic lung disease obviously also can cause high tricuspid insufficiency velocities. Finally , valvular pulmonic stenosis and peripheral pulmonic stenosis are by no means mutually exclusive. Pulsed wave Doppler can potentially pinpoint the location of flow acceleration at the pulmonic valve level, right ventricular outflow, and in the main pulmonary artery branches.
The most technically difficult transthoracic echo determination in the adult can be the presence or absence of peripheral pulmonary artery stenosis. The advent of transesophageal echocardiography has made it much easier to visualize the pulmonary artery bifurcation.
The first two patients progressed to a valvular gradient greater than 50 mm Hg. At that point it is generally agreed that the stenosis should be treated. Valvuloplasty provides a non surgical alternative as long as there is no asscociated atrial septal defect that needs to be closed surgically, and as long as the pulmonic valve is not exceedingly dysplastic.
REFERENCES
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2. Kan JS, White RI, Mitchell SE, Gardner TS. Percutaneous balloon valvuloplasty: a new method for treating congenital pulmonary valve stenosis. N Engl J Med 1982; 307:540.
3. Noonan JA. Hypertelorism with Turner phenotype. Am J Dis Child 1968; 116:373.
4. Johnson LW, Grossman W, Dalen JE, et al. Pulmonic stenosis in the adult: long term follow up results. N Engl J Med 1972; 287:1159.
5. Lynch JJ, Schuchard GH, Gross CM, Wann LS. Prevalence of right to left atrial shunting in a healthy population: detection by Valsalva maneuver contrast echocardiography. Am J Cardiol 1984; 53:1478.
6. Malzac P, Moncla A, Voelckel MA, et al. Prader-Willi syndrome: diagnostic strategy with a cytogenetic and molecular approach. Neuromuscul Disord 1993; 3:493.
7. Lima CO, Sahn DJ, Valdes-Cruz LM, et al. Noninvasive prediction of transvalvular pressure gradient in patients with pulmonary stenosis by quantitative two dimensional echocardiographic Doppler studies. Circulation 1983; 67:866.
e-mail:shindler@umdnj.edu