Pulmonary insufficiency I37.1

Pulmonary valve insufficiency (PI) is defined as a leakage or inability to close the pulmonary valve located between the right ventricle and the pulmonary arteries during diastole. This leakage primarily causes blood to flow back into the right ventricle (Wilkenshoff 2008).

PI is a rare valve disease. It can be congenital or acquired.

As a congenital vitium, a relevant pulmonary valve insufficiency occurs very rarely.

It is most commonly found secondary to ring dilatation caused by pulmonary hypertension. In this form of insufficiency, however, a relevant degree of severity is rarely reached.

The clinically relevant PI is primarily found iatrogenically due to previous interventions on the pulmonary valve (Karathanos 2019).

In adulthood, pulmonary insufficiency occurs more frequently than pulmonary stenosis (Erdmann 2006).

Organic inflammatory changes of the pulmonary valve are very rare. Functional pulmonary insufficiency is much more common (Riecker 1993).

Pulmonary insufficiency can result from primary valve disease, dilatation of the valve ring, or a combination of both (Kasper 2015). A distinction is made between functional and organic inflammatory pulmonary insufficiency (Riecker 1993).

Functional pulmonary insufficiency can be triggered:

• after catheter intervention or surgical treatment of pulmonary stenosis
• after surgical treatment:
  • for tetralogy of Fallot
  • after valve reconstruction with patch
  • after infundibulectomy

- in the context of a carcinoid syndrome (as so-called Hedinger syndrome; this usually causes both insufficiency and stenosis of the valve [Kasper 2015])

• isolated congenital pulmonary insufficiency (occurs only very rarely)
• Syndrome of the missing pulmonary valve
• as secondary pulmonary valve insufficiency due to
  • longstanding pulmonary hypertension (most common cause)
  • Dilatation of the pulmonary artery (Pinger 2019)
• Complications of a Ross operation (in which the defective aortic valve is replaced by a healthy pulmonary valve) (Kasper 2015)

Pulmonary valve insufficiency caused by organic inflammatory changes is most frequently triggered by bacterial endocarditis. In 2nd place is rheumatoid carditis (Riecker 1993)

Clinically, symptoms of the underlying disease predominate (Erdmann 2006). Even mild to moderate PI is usually asymptomatic. These only appear when pulmonary hypertension occurs (Kasper 2015).

The symptoms then consist of:

• Reduced performance
• dyspnea, initially only on exertion
• distended abdomen
• Liver enlargement
• Edema of the lower extremities (Kasper 2015).

High-grade pulmonary regurgitation results in dilatation and eccentric hypertrophy of the right ventricle. Both preload and afterload are increased. During diastole, the reverse pressure gradient between the truncus pulmonalis and the right ventricle decreases. This creates the descrescendo characteristic of the diastolic murmur. The murmur itself is shorter the more the pressure in the right ventricle increases during diastole (Kasper 2015).

Cardiac output can still be maintained in early stages of the disease, however, even then it is no longer possible to achieve an increase in HRV under stress, and there may even be a decrease in HRV as the disease progresses (Kasper 2015).

The regurgitation fraction - even in severe or complete pulmonary insufficiency - is only about 40%. This also explains the long tolerance of PI (Pinger 2019).

The first sign of compromised hemodynamics is a reduced right ventricular ejection fraction. In the further course, there is then a pronounced dilatation of the right atrium and the right ventricle with significantly increased central venous pressure (Kasper 2015).

Chest x-ray: The x-ray image may show an enlarged right ventricle and - in late sequelae of the disease - also an enlarged right atrium (Kasper 2015).

The central pulmonary arteries are dilated, while the peripheral pulmonary arteries are narrow or may be normally wide (Riecker 1993).

MRI: If the diagnostic findings are unclear, MRI can be used to quantitatively determine right ventricular myocardial hypertrophy, as well as morphological morphometric evaluation of the pulmonary parenchyma for differential diagnosis of pulmonary hypertension (Riecker 1993).

Cardiac MRI: Gold standard is cardiac MRI for the assessment and quantification of the regurgitation fraction and the assessment of the right ventricle, including its ejection fraction (RV- EF). Sometimes MRI is also used for follow-up purposes (Pinger 2019).

Doppler echocardiography: The transthoracic echo allows the morphology and function of the pulmonary valve to be determined. The pulmonary arterial pressure over the tricuspid valve can be estimated from the speed of the systolic regurgitation jet (Kasper 2015). The lack of sufficiently validated parameters makes it difficult to determine the severity of PI echocardiographically. The EAE (European Association of Echocardiography) states a jet width of > 65% of RVOT (right ventricular outflow tract) as a sign of severe pulmonary insufficiency (Pinger 2019).

Cardiac catheterization: Cardiac catheterization is not part of the standard diagnostic procedure and should only be performed as part of an already planned catheter intervention (Kasper 2015).

Auscultation: The typical characteristic of a PI is a high-frequency descrescendo noise during diastole. This is caused by the fact that during diastole the reverse pressure gradient between the pulmonary trunk and the right ventricle decreases. The noise can be auscultated at the left sternal margin with a pointum maximum in the 2nd or 3rd ICR (Riecker 1993) and is named after its first descriptor (Graham Steell 1851 - 1942) Graham- Steell- Noise. The volume of the sound can increase during inspiration (Kasper 2015).

If the PI has developed secondarily, e.g. in the context of mitral valve stenosis, the noise is loud and high-frequency. In a PI that has developed as a result of pulmonary hypertension, it is rather low frequency with a rumbling crescendo-decrescendo character (Riecker 1993).

Often there is also a loud - sometimes palpable - pulmonary component of the 2nd heartbeat as well as a lifting apex of the heart (Kasper 2015).

EKG: In the ECG there are signs of right heart strain such as:

• Sokolow- Lyon- Index: RV1 + SV 5 / 6 > 1,05 mV
• Right deviation of the heart axis (Herold 2018)
• End distance changes in SV1 and SV 5 (Erdmann 2006)

The treatment of a PI consists of conservative and operative measures.

Conservative therapy:

• Diuretics for edema
• ACE inhibitors or beta-blockers should be used on an experimental basis to antagonize increased neurohormonal activation (Pinger 2019).

The surgical treatment consists of implantation of a valve replacement. This can be done by a percutaneous pulmonary valve implantation or by a surgically inserted valve replacement (Karathanos 2019). In Germany, two different catheter valves have been approved for the minimally invasive procedure (Kasper 2015): a replacement specially developed for the pulmonary valve and another valve system which can also be used for aortic stenosis (Karathanos 2019).

Today, catheter-assisted minimally invasive implantation is preferred (Kasper 2015). Due to the lower complication rate, a bioprosthesis is preferred (Pinger 2019).

However, even in the case of high-grade lesions of the pulmonary valve, such as those occurring in endocarditis or carcinoid syndrome, a primarily surgical valve replacement is only rarely necessary. In such cases, conservative measures and regular monitoring are usually sufficient for the time being (Kasper 2015).

However, there is an indication for valve replacement if there is increasing right ventricular dilatation in addition to severe PI. If possible, the surgical measure should be taken before the onset of a dysfunction of the right ventricle, as such a dysfunction is irreversible. [pingers 2019]

The perioperative mortality of this procedure is 1 % - 4 %. The functional duration of the prostheses in adults is between 15 - 30 years (Pinger 2019).

Basically, it can be said that in valve insufficiency, the resulting volume load, which leads to eccentric hypertrophy, has a more favourable prognosis compared to a pressure load with concentric hypertrophy (Herold 2018).

In patients with PI, the 10-year survival rate is between 86 % - 95 % (Pinger 2019). Erdmann (2006) emphasizes that life expectancy for patients with PI is limited only when pulmonary hypertension is present at the same time and is determined by the disease underlying pulmonary hypertension.

Patients who have had a mechanical prosthesis implanted require permanent oral anticoagulation with vitamin K antagonists. Recommended dosage: Marcumar 3 mg 2 x 1 tbl/d for the first 3 days, then dose adjustment according to the INR value. Alternatively, the preparation Falithrom 3 mg can be given in the same dosage (Herold 2018) The INR target value should be between 2 - 3 (Kasper 2015).

In patients with bioprosthesis, anticoagulation for 3 - 6 months postoperatively should be considered. Afterwards, a lifelong therapy with acetylsalicylic acid is recommended. For percutaneous valve replacement of the pulmonary valve there are no guideline recommendations available so far (Karathanos 2019).

Patients with valve reconstruction or prosthetic heart valve have a significantly increased risk of endocarditis. The post-procedural bacteremia frequency after tooth extractions in gingivitis is up to 90%. Therefore, after pulmonary valve replacement, endocarditis prophylaxis is required for life after certain procedures (Karathanos 2019). The standard therapy is administered as a single dose approx. 30-60 minutes before the procedure, e.g. amoxicillin or ampicillin 2 g orally or i.v., or in the case of penicillin allergy clindamycin 600 mg also orally or i.v. (Pinger 2019).

For further details see Endocarditis prophylaxis

Control examinations, including echocardiography, are recommended postoperatively for the first time after 3 months and otherwise once a year. The connection to a centre of excellence is certainly sensible (Karathanos 2019).

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8. Wilkenshoff U et al (2008) Manual of Echocardiography. Thieme Publishing House 114 - 115