Current Medical Diagnosis & Treatment 2015

10

Heart Disease

Thomas M. Bashore, MD
Christopher B. Granger, MD
Kevin Jackson, MD
Manesh R. Patel, MD

CONGENITAL HEART DISEASE

In the United States, there are more adults with congenital heart disease than children, with over 1.5 million adults in the United States surviving with congenital heart disease.

Baumgartner H et al; Task Force on the Management of Grown-up Congenital Heart Disease of the European Society of Cardiology (ESC); Association for European Paediatric Cardiology (AEPC); ESC Committee for Practice Guidelines (CPG). ESC Guidelines for the management of grown-up congenital heart disease (new version 2010). Eur Heart J. 2010 Dec;31(23):2915–57. [PMID: 20801927]

Warnes CA et al. ACC/AHA 2008 Guidelines for the Management of Adults With Congenital Heart Disease. A Report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. Circulation. 2008 Dec 2;118(23):e714–833. [PMID: 18997169]

PULMONARY VALVE STENOSIS

 ESSENTIALS OF DIAGNOSIS

 Severe cases may present with right-sided heart failure.

 P2 delayed and soft or absent.

 Ejection click often present and decreases with inspiration—the only right heart auscultatory event that decreases with inspiration, all others increase.

 Echocardiography/Doppler is diagnostic.

 Patients with peak pulmonic valve gradients > 60 mm Hg or mean of 40 mm Hg by echocardio-graphy/Doppler should undergo intervention regardless of symptoms.

 General Considerations

Stenosis of the pulmonary valve or right ventricular (RV) infundibulum increases the resistance to RV outflow, raises the RV pressure, and limits pulmonary blood flow. Pulmonic stenosis is often congenital, associated with other cardiac lesions. Pulmonary blood flow preferentially goes to the left lung in valvular pulmonic stenosis. In the absence of associated shunts, arterial saturation is normal. Infundibular stenosis may be so severe that the RV is divided into a low-pressure and high-pressure chamber (double-chambered RV). Peripheral pulmonic stenosis can accompany valvular pulmonic stenosis and may be part of a variety of clinical syndromes, including the congenital rubella syndrome. Patients who have had the Ross procedure for aortic valve disease (transfer of the pulmonary valve to the aortic position with a homograft pulmonary valve placed in the pulmonary position) may experience postoperative (noncongenital) pulmonic stenosis due to an immune response in the homograft. RV outflow obstructions can also occur when there is a conduit from the RV to the pulmonary artery (PA) that becomes stenotic.

 Clinical Findings

  1. Symptoms and Signs

Mild cases of pulmonic stenosis are asymptomatic; moderate to severe pulmonic stenosis may cause symptoms of dyspnea on exertion, syncope, chest pain, and eventually RV failure.

On examination, there is often a palpable parasternal lift due to right ventricular hypertrophy (RVH) and the pulmonary outflow tract may be palpable if it is enlarged. A loud, harsh systolic murmur and occasionally a prominent thrill are present in the left second and third interspaces parasternally. The murmur radiates toward the left shoulder due to the flow pattern and increases with inspiration. In mild to moderate pulmonic stenosis, a loud ejection click can be heard to precede the murmur; this sound decreases with inspiration as the increased RV filling from inspiration prematurely opens the valve during atrial systole. This is the only right-sided auscultatory event that decreases with inspiration. The reason for this is that the valve excursion in systole is less with inspiration than with expiration. This relates to premature opening of the pulmonary valve with the atrial kick into the RV. The click therefore diminishes in intensity when more volume is ejected into the RV with inspiration, raising the RV diastolic pressure. The second sound is obscured by the murmur in severe cases; the pulmonary component may be diminished, delayed, or absent. A right-sided S4 and a prominent a wave in the venous pulse are present when there is RV diastolic dysfunction or a c-v wave if there is tricuspid regurgitation present. Pulmonary valve regurgitation is relatively uncommon in primary pulmonic stenosis and may be very difficult to hear, as the gradient between the reduced PA diastolic pressure and the elevated RV diastolic pressure may be quite small (low-pressure pulmonary valve regurgitation).

  1. ECG and Chest Radiography

Right axis deviation or RVH is noted; peaked P waves provide evidence of right atrial (RA) overload. Heart size may be normal on radiographs, or there may be a prominent RV and RA or gross cardiac enlargement, depending on the severity. There is often poststenotic dilation of the main and left pulmonary arteries. Pulmonary vascularity is usually normal.

  1. Diagnostic Studies

Echocardiography/Doppler is the diagnostic tool of choice, can provide evidence for a doming valve versus a dysplastic valve, can determine the gradient across the valve, and can provide information regarding subvalvular obstruction and the presence or absence of tricuspid or pulmonic valvular regurgitation. Mild pulmonic stenosis is present if the peak gradient by echocardiography/Doppler is < 30 mm Hg, moderate pulmonic stenosis is present if the peak gradient is between 30 mm Hg and 60 mm Hg, and severe pulmonic stenosis is present if the peak gradient is > 60 mm Hg or the mean gradient is > 40 mm Hg. Catheterization is usually unnecessary for the diagnosis; it should be used only if the data are unclear or in preparation for either a percutaneous intervention or surgery.

 Prognosis & Treatment

Patients with mild pulmonic stenosis have a normal life span with no intervention. Moderate stenosis may be asymptomatic in childhood and adolescence, but symptoms often appear as patients grow older. The degree of stenosis does worsen with time in many patients, so serial follow-up is important. Severe stenosis is rarely associated with sudden death but can cause right heart failure in patients as early as in their 20s and 30s. Pregnancy and exercise tends to be well tolerated except in severe stenosis.

Class I indications for intervention include all symptomatic patients and all those with a resting peak gradient > 60 mm Hg or mean > 40 mm Hg, regardless of symptoms. Percutaneous balloon valvuloplasty is highly successful in domed valve patients and is the treatment of choice. Surgical commissurotomy can also be done, or pulmonary valve replacement (with either a bioprosthetic valve or homograft) when pulmonary valve regurgitation is too severe or the valve is dysplastic. Pulmonary outflow tract obstruction due to RV to PA conduit obstruction or to homograft pulmonary valve stenosis can be relieved with a percutaneously implanted pulmonary valve. The applicability of this approach to primary pulmonic valve stenosis remains under investigation.

Endocarditis prophylaxis is unnecessary for native valves even after valvuloplasty unless there has been prior pulmonary valve endocarditis (a very rare entity) (see Table 33–4).

 When to Refer

All symptomatic patients, and all asymptomatic patients whose peak pulmonary valve gradient is > 60 mm Hg or mean gradient > 40 mm Hg, should be referred to a cardiologist with expertise in adult congenital heart disease.

Bashore TM. Adult congenital heart disease: right ventricular outflow tract lesions. Circulation. 2007 Apr 10;115(14):1933–47. [PMID: 17420363]

Odenwald T et al. Pulmonary valve interventions. Expert Rev Cardiovasc Ther. 2011 Nov;9(11):1445–57. [PMID: 22059793]

Warnes CA et al. ACC/AHA 2008 Guidelines for the Management of Adults With Congenital Heart Disease. A Report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines. Circulation. 2008 Dec 2;118(23):e714–833. [PMID: 18997169]

COARCTATION OF THE AORTA

 ESSENTIALS OF DIAGNOSIS

 Usual presentation is systemic hypertension.

 Echocardiography/Doppler is diagnostic; a gradient of > 20 mm Hg may be significant due to collaterals around the coarctation, reducing gradient despite severe obstruction.

 Associated bicuspid aortic valve (in 50–80% of patients).

 Systolic pressure is higher in upper extremities than in lower extremities; diastolic pressures are similar.

 General Considerations

Coarctation of the aorta consists of localized narrowing of the aortic arch just distal to the origin of the left subclavian artery. Collateral circulation develops around the coarctation through the intercostal arteries and the branches of the subclavian arteries and can result in a lower transcoarctation gradient by enabling blood flow to bypass the obstruction. Coarctation is a cause of secondary hypertension and should be considered in young patients with elevated blood pressure (BP). The renin–angiotensin system is reset, however, and contributes to the hypertension occasionally seen even after coarctation repair. A bicuspid valve is seen in over 50–80% of the cases, and there is an increased incidence of cerebral berry aneurysms.

 Clinical Findings

  1. Symptoms and Signs

If cardiac failure does not occur in infancy, there are usually no symptoms until the hypertension produces left ventr