Valvar Pulmonary Stenosis Treatment & Management

Updated: Jun 26, 2014
  • Author: Syamasundar Rao Patnana, MD; Chief Editor: Howard S Weber, MD, FSCAI  more...
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Treatment

Medical Care

Prehospital care in patients with pulmonary valve stenosis

Collect essential information about vital signs, including the patient's pulse, respiratory rate, work of breathing, and blood pressure (BP) in the upper and lower extremities. Note the presence or absence of cyanosis.

Associated congenital cardiac anomalies should be anticipated until proven otherwise.

If the patient has a known large left-to-right shunt, such as patent ductus arteriosus (PDA) or ventricular septal defect (VSD), and if the patient is in respiratory distress, diuresis should be attempted. Diuresis is effective in reducing the cyanosis secondary to pulmonary edema, which is unusual in patients with isolated pulmonary valve stenosis.

Use of oxygen may reduce pulmonary artery pressure in patients with a reactive pulmonary vasculature, increasing pulmonary blood flow, which is also unusual in patients with isolated pulmonary valve stenosis.

Administer oxygen to any patient with cyanosis and respiratory distress. However, cyanosis-related intracardiac right-to-left shunting does not resolve hypoxemia.

Emergency department care

Limited diagnostic tests are needed after the structural diagnosis is made. Workup performed for the cyanotic infant with respiratory distress and hypotension or shock is often the same as that performed in a septic patient.

If a neonate or young infant presents to the emergency room with severe cyanosis, ductal dependent lesions should be considered. Prostaglandin infusion may open the ductus, augment pulmonary blood flow, and improve oxygen saturation.

Therapeutic approach

Patients with trivial (gradient < 25 mm Hg) or mild (gradient < 50 mm Hg) pulmonary stenosis do not need intervention to relieve the obstruction of the pulmonary valve. [43] They should be clinically followed up at periodic intervals, perhaps on a yearly basis. During the period of rapid growth (infancy and adolescence), follow-up more frequent than this may be indicated. Routine well-child care, including immunizations by the primary physician, should be provided. Patients with pulmonary stenosis are candidates for infective endocarditis prophylaxis before they undergo any bacteremia -producing procedures and surgery, as indicated in the recommendations of the American Heart Association. Limitations in exercise or activity levels are not needed.

Patients with moderate (gradient, 50-79 mm Hg) and severe (gradient, >80 mm Hg) obstruction should undergo intervention to relieve the stenosis of the pulmonary valve. After the obstruction is relieved, recommended routine care, endocarditis prophylaxis, and exercise limitations are the same as those described for trivial and mild stenosis.

Patients with signs of right ventricular failure should be promptly treated with anticongestive measures, including digitalis and diuretics. However, the problem does not resolve until the obstruction is relieved. Therefore, prompt balloon or surgical intervention should be undertaken. Right ventricular function may not recover completely if intervention is withheld for too long and if myocardial damage sets in.

A fetus with critical pulmonary stenosis or atresia with intact ventricular septum may benefit from pulmonary balloon valvuloplasty in utero, which promotes growth of the right ventricle. [44, 45]

Although the consensus is to offer relief of pulmonary valve obstruction in children with moderate or severe stenoses, this approach is somewhat controversial in adults because of reported lack of progression and the lack of complications in 1 group of adults monitored for 5-24 years in the 1970s. [16] However, a prudent strategy may be to relieve pulmonary valve obstruction in adults with moderate-to-severe pulmonary stenosis, irrespective of their symptoms, because of the potential (1) for myocardial damage associated with long-term pressure overload of the right ventricle, [46] (2) for generally lowered cardiac indices both before and after exercise in adults compared with children, [47] and (3) for exercise-induced hemodynamic abnormalities in adults. [47]

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Surgical Care

Balloon pulmonary valvuloplasty

Rubio-Alverez et al first attempted to relieve pulmonary valve obstruction with transcatheter methods in the early 1950s. [48] They used a ureteral catheter with a wire to cut open the stenotic pulmonary valve.

In 1979, Semb et al used a balloon-tipped angiographic (Berman) catheter to rupture pulmonary valve commissures by rapidly withdrawing the inflated balloon across the valve. [49]

More recently, Kan et al [50] applied the techniques of Dotter and Judkins [51] and Gruntzig et al [52] to relieve pulmonary valve obstruction by using the radial forces of balloon inflation of a balloon catheter positioned across the pulmonic valve. This static balloon-dilation technique is currently performed worldwide to relieve pulmonary valve obstruction.

The general consensus based on current data is that balloon valvuloplasty is the treatment of choice for managing isolated pulmonary valve stenosis. [53, 54]

Indications

In general, indications for balloon pulmonary valvuloplasty are similar to those used in surgical pulmonary valvotomy (ie, moderate pulmonary valve stenosis with a peak-to-peak gradient >50 mm Hg with a normal cardiac index). Some cardiologists change this criterion to a gradient of 40 mm Hg or right ventricular pressure of 50 mm Hg. Careful evaluation of the available data suggests that (1) right ventricular pressure is only marginally reduced if mildly stenotic valves are dilated, [41] (2) trivial and mild stenoses (gradient < 50 mm Hg) are likely to remain mild at follow-up (as shown in natural-history studies), [42, 55] and (3) an increase in gradient is easily quantitated on follow-up Doppler echocardiography. [32, 32, 33, 34] If an increased gradient is documented, the patient can then undergo balloon dilatation. Given these observations, balloon dilation should be performed only in patients with peak-to-peak gradient of more than 50 mm Hg.

More recently, the interventional procedures are increasingly performed under general anesthesia and the gradients are usually lower with general anesthesia than with conscious sedation. Consequently, the same criteria should not be applied. Therefore, the Doppler gradients (discussed in Echocardiography) should be used in making the decision regarding balloon pulmonary valvuloplasty.

Technique

The technique of balloon pulmonary valvuloplasty involves positioning a balloon catheter (see the image below) across the stenotic valve, usually over an extra-stiff exchange-length guide wire and inflating the balloon with diluted contrast material to accomplish valvotomy. [56, 57]

Selected cineradiographic frames of a balloon dila Selected cineradiographic frames of a balloon dilatation catheter placed across a stenotic pulmonary valve. Note "waisting" of the balloon during the initial phases of the balloon inflation (A), which was almost completely abolished during the later phases of balloon inflation (B). Reproduced from Rao PS: Balloon pulmonary valvuloplasty for isolated pulmonic stenosis. In: Rao PS, ed: Transcatheter Therapy in Pediatric Cardiology New York, NY: Wiley-Liss; 1993: 59-104.

The initially recommended balloon-to-annulus ratio was 1.2-1.4 [55, 58, 59] ; subsequent data suggested a ratio of 1.2-1.25. [60, 61] When the pulmonary valve annulus is too large to dilate with a single balloon (about 20 mm), valvuloplasty with simultaneous inflation of 2 balloons across the pulmonary valve may be performed, [62, 63] although the current availability of large-diameter balloons make this technique unnecessary. However, the double balloon technique may be more effective and stable in some cases. The Inoue balloon has been used in adults with success. [64] The major advantage of the Inoue balloon over conventional balloons is its adjustable diameter that makes stepwise dilation possible. Nucleus balloons with a waist in the middle have been approved by FDA. They do have theoretical advantage; however, these balloons require large sheaths and not a lot of clinical experience has been accumulated so far.

The results of balloon pulmonary valvuloplasty for patients with dysplastic pulmonary valves are generally poor with the use of conventional balloon pulmonary valvuloplasty techniques. Use of large balloons, up to 150% of pulmonary valve annulus, [65] or high-pressure balloons [66] may increase the effectiveness of balloon therapy and avoid the need for surgery.

Mechanism of valvuloplasty

Inflation of a balloon placed across an obstructive lesion exerts radial forces on the stenotic lesion without any axial component. [67, 68]

The mechanism of valvuloplasty is assessed by directly visualizing the valvar mechanism during surgery [69] and postmortem examination [70] and by indirect means, such as angiography and echocardiography. [71, 72] Splitting of the valve commissures and tearing and avulsion of the valve leaflets have been observed and are conceivably the mechanism by which balloon dilation relieves pulmonary valve obstruction. The circumferential dilating force that balloon inflation exerts is likely to rupture (tear) the weakest part of the valve mechanism. The fused commissures are the likely weakest links that can be broken with balloon dilation. However, when fused commissures are strong and cannot be torn, the valve cusps can be torn or the valve leaflet avulse. These events are likely to worsen pulmonary insufficiency.

Pulmonary valve dysplasia, if severe, may preclude successful balloon valvuloplasty unless an associated commissural fusion is present. [65, 73]

Immediate results

Results observed immediately after balloon valvuloplasty include reduced peak-to-peak gradients and right ventricular–to–left ventricular pressure ratios and increased pulmonary artery pressures, jet widths, and free motion of the pulmonary valve leaflets with decreased doming. [53, 54, 74, 75, 76] Improvement of right ventricular function, tricuspid insufficiency, [53] and right-to-left shunt, [12] if present before dilation, are also documented.

Infundibular stenosis

Infundibular gradients occur in nearly 30% patients. [12, 77] The older the patient's age and the greater the severity of obstruction, the greater the prevalence of infundibular reaction. When residual infundibular gradient is >50 mm Hg beta-blockade is generally recommended. Infundibular obstruction greatly regresses at follow-up (see the image below), [5] as demonstrated for infundibular reactions after surgical valvotomy. [78, 79, 80] Rare patients require surgical intervention.

Selected frames from lateral view of the right ven Selected frames from lateral view of the right ventricular (RV) cineangiogram showing severe infundibular stenosis (A) immediately following balloon valvuloplasty (corresponding Media file 3, center). At 10 months after balloon valvuloplasty, the right ventricular outflow tract (B) is wide open and corresponds to Media file 3, right. Peak-to-peak pulmonary valve gradient was 20 mm Hg and no infundibular gradient was present. PA = Pulmonary artery. Reproduced with permission from Thapar MK: Significance of infundibular obstruction following balloon valvuloplasty for valvar pulmonic stenosis. Am Heart J 1989; Jul; 118(1): 99-103.

Follow-up evaluation

Clinical, ECG, and Doppler echocardiographic evaluations are generally recommended at 1 month, 6 months, and 12 months after the procedure and yearly thereafter. [53, 54, 74, 81] Regression of right ventricular hypertrophy, as shown on ECG after balloon dilatation, is well documented. ECG is a useful adjunct in the evaluation of follow-up results. [82] However, ECG evidence of hemodynamic improvement does not become apparent until 6 months after valvuloplasty. [82] The Doppler gradient generally reflects residual obstruction and is a useful and reliable noninvasive monitoring tool. [53, 74, 75, 83]

Intermediate-term results

At intermediate-term follow-up (usually < 2 y), both catheterization-measured peak-to-peak and Doppler-measured peak instantaneous gradients remain improved as a whole. [53, 54, 74] However, restenosis (gradient >50 mm Hg) is observed in nearly 10% patients. [84]

Predictors of restenosis include a balloon-to-annulus ratio of less than 1.2 and a gradient of more than 30 mm Hg immediately after valvuloplasty. In addition, early in the study period, a small valve annulus, and a postsurgical or complex pulmonary stenosis were also predictive of restenosis. [85]

Patients with restenosis have been successfully treated with redilatation with balloons larger than those used for initial balloon valvuloplasty. [86] Redilatation is the procedure of choice for managing restenosis after previous balloon dilatation. However, if the pulmonary valve annulus is hypoplastic, if the pulmonary valve leaflets are dysplastic, or if clinically significant supravalvar pulmonary artery stenosis is the major reason for the restenosis, surgery is recommended.

Long-term follow-up results

Although immediate and short-term results have been documented, [76, 81] data on long-term results are scarce. Published studies reveal generally low residual peak instantaneous Doppler gradients with minimal (1-2%) late recurrence of pulmonary stenosis (beyond that seen at intermediate follow-up). [59, 76]

In one study, approximately 5% of patients needed surgical intervention to relieve fixed subvalvar or supravalvar stenosis. [76] Actuarial freedom for reintervention was 88% and 84%, respectively, at 5 and 10 years. Pulmonary valve insufficiency was noted in 80-90% patients, but right ventricular volume overloading did not develop, and none of the patients required surgical intervention because of pulmonary insufficiency. Based on these data, the authors concluded that balloon pulmonary valvuloplasty may continue to be the treatment of choice for moderate-to-severe valvar pulmonary stenosis, and 10-year to 20-year follow-up studies to evaluate the clinical significance of residual pulmonary insufficiency should be undertaken.

Clinically significant pulmonary insufficiency

One report documented the development of clinically significant pulmonary insufficiency in 6 (6%) of 107 patients at late follow-up. Some of these patients required pulmonary valve replacement. [60] In a recent report, 53 patients with pulmonary valve stenosis who had percutaneous balloon valvuloplasty were followed for 10-24 years (median, 15 years); there was only 2% prevalence of restenosis, but late pulmonary regurgitation developed in 89% patients. [87]

Comparison with surgical valvotomy

Comparison of balloon therapy with surgical valvotomy has limitations, [53, 76] but the mortality and morbidity rates are generally higher after surgery. Greater reduction of the gradient is observed after surgery, but the degree and frequency of pulmonary insufficiency may be higher after surgery than after balloon therapy. [88, 89]

Critical pulmonary stenosis in the neonate

The term critical pulmonary stenosis with intact ventricular septum is applied to severe pulmonary valvar obstruction resulting in suprasystemic right ventricular systolic pressure with resultant tricuspid insufficiency, a right-to-left shunt across the atrial septum, and often a ductal-dependent pulmonary circulation.

Although the surgical approach to relieve the obstruction with or without aorta-pulmonary shunt was standard treatment in the past, transcatheter treatment is now first-line therapy.

Prostaglandin E1 is infused to augment pulmonary blood flow and improve systemic arterial desaturation, followed by cardiac catheterization and biplane (sitting-up and lateral views) right ventricular cineangiography. A right coronary artery, angled glide, balloon wedge, or cobra catheter (according to the operator's preference) is placed in the right ventricular outflow tract, and a floppy-tipped coronary guidewire is advanced across the pulmonary valve and into the right or left pulmonary artery or into the descending aorta through the ductus. The catheter is advanced across the pulmonary valve into a distal pulmonary artery or the descending aorta. The guidewire is then exchanged for a guidewire that is suited to position the balloon-dilation catheter. Then, balloon pulmonary valvuloplasty is performed in manner described earlier. [90, 91]

In some cases, the balloon catheter cannot be advanced across a severely stenotic pulmonary valve, and balloon catheters 3-6 mm in diameter may be used for initial predilation and then replaced with larger, more appropriately sized balloon catheters.

Although the results of this approach are reasonably good, the need for reintervention to address the complications associated with the procedure, residual obstruction, or associated defects is 25% in neonates compared with older children 8-10%. [90, 91, 92]

Other catheter interventions

Numerous other catheter interventions may become necessary in patients with pulmonary stenosis.

Transcatheter occlusion of a patent ductus arteriosus (PDA)

Some patients with pulmonary stenosis may have a PDA of significant size. In such patients, transcatheter occlusion of the PDA performed with a coil (for small PDAs) or with an Amplatzer duct occluder (for medium or large PDAs) is recommended immediately after balloon pulmonary valvuloplasty. (See also the article Patent Ductus Arteriosus.)

Occlusion of a patent foramen ovale or atrial septal defect

A patent foramen ovale or atrial septal defect may occur in association with pulmonary stenosis. If these atrial defects do not spontaneously close during follow-up after balloon valvuloplasty, they may be closed with an Amplatzer septal occluder or Helex device, if the criteria for their closure are met. Sometimes, the defects may need to be closed to prevent recurrent paradoxical embolisms. (See also the article Atrial Septal Defect, General Concepts.)

Balloon atrial septostomy [52]

In neonates with a severely hypoplastic right ventricle, balloon atrial septostomy may be necessary to provide adequate egress to the systemic venous return. Indications are clinical signs of systemic venous congestion, restrictive patent foramen ovale on Doppler echocardiography, markedly elevated right atrial pressure with tall a waves, and/or a mean atrial pressure difference of more than 5 mm Hg.

In neonates, Rashkind balloon septostomy is effective. Beyond the neonatal period, Park blade septostomy or surgical septostomy may be necessary. In patients with only mild or moderate right ventricular hypoplasia, balloon septostomy should be avoided so that forward flow through the right ventricle is encouraged with a consequent opportunity for its growth.

Cardiac catheterization with balloon valvuloplasty

This is the preferred therapy for severe or critical valvar pulmonary stenosis. In neonates with critical valvar pulmonary stenosis, mortality rates related to balloon dilation are lower than those related to surgery mortality, and balloon dilation is the treatment of choice.

Other surgical techniques

Since the first description of surgical relief of pulmonary stenosis by closed pulmonary valvotomy in the late 1940s, [93, 94] various techniques were developed and include valvotomy with inflow occlusion, hypothermia and cardiopulmonary bypass. The currently preferred approach is transpulmonary arterial valvotomy under cardiopulmonary bypass. [95]

Results

Results of surgery are generally good with low mortality rate (3-7%) and decreased right ventricular pressures and pulmonary valve gradients. In a natural-history study in the United States, only 3% of 294 operated patients had gradients of more than 50 mm Hg at 4-8 years after surgery. [42] The incidence of pulmonary insufficiency at follow-up was 60-90%. [96] Despite these good results, transluminal balloon pulmonary valvuloplasty (discussed above) has replaced surgical pulmonary valvotomy.

Indications

Surgery is reserved for cases in which balloon valvuloplasty is not feasible or not successful. One example is dysplastic pulmonary valve with valve ring hypoplasia. The treatment of this disorder is to excise the obstructive valve leaflets and enlarge the annulus by a transannular patch. Other examples are fixed infundibular and supravalvar stenosis after successful balloon valvuloplasty. [76]

Blalock-Taussig shunt

Patients with critical pulmonary stenosis and marked hypoplasia of the right ventricle may need a Blalock-Taussig shunt in addition to or instead of balloon or surgical valvotomy.

Right ventricular repair/bypass

Right ventricular hypoplasia, as alluded to above, occurs in some patients with pulmonary stenosis, although this hypoplasia is most common in patients with pulmonary atresia and an intact ventricular septum. The right ventricle may enlarge after right ventricular outflow obstruction is relieved, particularly in tripartite right ventricles. [97, 98, 99]

If the right ventricle does not grow adequately to support the pulmonary circulation, 1.5 or single ventricular repair should be considered. In 1.5-ventricular repair, a bidirectional Glenn procedure (superior vena cava–to–right pulmonary artery anastomosis, end to side) is performed to divert the blood from the upper part of the body directly into the pulmonary artery, and the atrial septal defect is closed to allow the blood from the lower part of the body to go into the lungs through the right ventricle. In the single ventricle repair, the right ventricle is bypassed by the Fontan procedure. In the Fontan procedure, staged total cavopulmonary connection is performed by bidirectional Glenn initially and then extra conduit diversion of the inferior cava into the pulmonary artery.

See the article Tricuspid Atresia.

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Consultations

Consultation with a pediatric cardiologist precedes consultation with a cardiothoracic surgeon.

Patients with pulmonary valve atresia or a critical pulmonary stenosis with an inadequate right ventricle require a shunt (usually a modified Blalock-Taussig or central shunt) after the ductus arteriosus is pharmacologically kept patent with prostaglandin E1.

Definitive repair may not be possible if the right ventricle is hypoplastic. Single ventricular palliation, such as the Fontan procedure, or variation, such as staged total cavopulmonary connection, may be required.

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Activity

A prudent philosophy is to allow patients to limit their own activity according to personal tolerance.

Restriction from highly exertional and competitive sports is recommended only for patients with severe pulmonary stenosis.

After successful relief of the obstruction, normal activity may be resumed.

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