Cardiovascular Board Review

An elderly woman with shortness of breath

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WHAT IS THE NEXT STEP?

2. What would be the most appropriate next step for our patient?

  • Transesophageal echocardiography
  • Right heart catheterization
  • An exercise treadmill stress test0

Transesophageal echocardiography is a reasonable option, as mitral stenosis is strongly suspected but transthoracic echocardiography did not reveal severe mitral valve disease. The use of transesophageal echocardiography for the diagnosis of mitral stenosis in this situation is a class IC recommendation (ie, the procedure is recommended, although very few trials have been done) in the American College of Cardiology and American Heart Association Valvular Disease guidelines.3

Right heart catheterization is the diagnostic test of choice in this situation, as the patient has evidence of biventricular heart failure and her right ventricular systolic pressure of 90 mm Hg is consistent with severe pulmonary hypertension. Right heart catheterization would help differentiate primary pulmonary hypertension causing dyspnea from pulmonary hypertension secondary to elevated left-sided pressures. It would also provide a direct hemodynamic estimate of her cardiac function.

Exercise treadmill testing. Evaluation for myocardial ischemia is a reasonable option, as our patient is elderly and has hypertension and diabetes, both of which are risk factors for coronary artery disease. Moreover, in a patient with diabetes, myocardial ischemia can present as dyspnea without typical anginal chest pain. Because of her age and severely limiting dyspnea, however, she would be unlikely to achieve an adequate heart rate during exercise treadmill testing, so this may not be the optimal type of stress test.

Although asymptomatic patients with moderate or severe mitral stenosis should undergo evaluation of exercise capacity and change in pulmonary artery pressures with exercise to determine the need for percutaneous balloon mitral valvuloplasty (see below),3 our patient is symptomatic and already has evidence of severe pulmonary hypertension on transthoracic echocardiography.

Other options for evaluating for myocardial ischemia include pharmacologic stress testing with imaging (eg, dobutamine echocardiography or adenosine nuclear imaging) or proceeding directly to coronary angiography.

CASE CONTINUED: RIGHT HEART CATHETERIZATION, CORONARY ANGIOGRAPHY

Figure 1. Simultaneous hemodynamic tracing of pulmonary capillary wedge pressure (blue arrow) and left ventricular pressure (red arrow) shows a clear gradient between the estimated left atrial pressure (ie, the wedge pressure) and the left ventricular pressure.

Given her persistent symptoms of shortness of breath and a transthoracic echocardiogram that was unrevealing for severe valvular pathology or cardiomyopathy, the patient is referred for right heart catheterization (Figure 1). Findings:
  • Mean right atrial pressure 6 mm Hg (normal 2–7 mm Hg)
  • Right ventricular pressure 102/6 mm Hg (consistent with severe pulmonary hypertension) (normal 15–30/1–7 mm Hg)
  • Pulmonary artery pressure 102/40 mm Hg (normal 15–30/4–12 mm Hg)
  • Mean pulmonary capillary wedge pressure 25 mm Hg (normal 4–12 mm Hg)
  • Cardiac output 3.16 L/min (normal 4–8 L/min)
  • Cardiac index 2.10 L/min/m2 (normal 2.5–4.2 L/min/m2)
  • v waves are not prominent.

Because her symptoms raise concern for ischemia, coronary angiography is also performed and shows minimal, nonobstructive coronary artery disease. Her left ventricular end-diastolic pressure is 8 mm Hg (normal 5–12 mm Hg).

WHAT IS THE DIAGNOSIS?

3. What is the most likely diagnosis?

  • Tricuspid stenosis
  • Pulmonic stenosis
  • Mitral stenosis
  • Mitral regurgitation

Tricuspid stenosis would result in a higher pressure in the right atrium than in the right ventricle. In our patient, the right atrial pressure and the right ventricular diastolic pressure are both 6 mm Hg, eliminating this possibility.

Similarly, pulmonic stenosis would result in a higher pressure in the right ventricle than in the pulmonary artery. In our patient both the right ventricular systolic pressure and the pulmonary artery systolic pressures are 102 mm Hg.

Acute mitral regurgitation may result in increased wedge pressure and tall v waves (reflecting left atrial filling during ventricular systole). In chronic mitral regurgitation, however, the wedge pressure may be normal and the patient may have relatively normal-appearing v waves.4

Mitral stenosis results in a marked gradient between the pulmonary capillary wedge pressure and the left ventricular diastolic pressure in the absence of pulmonary veno-occlusive disease. This gradient can be measured by simultaneous catheterization of the right heart (to measure the wedge pressure, which is an indirect measure of left atrial pressure) and the left heart (to measure the left ventricular diastolic pressure). If the patient does not have significant mitral stenosis, the wedge pressure should be approximately equal to the left ventricular diastolic pressure. In our patient, the wedge pressure (and therefore the left atrial pressure) is 25 mm Hg, and the left ventricular end-diastolic pressure is 8 mm Hg—a difference of 17 mm Hg, consistent with significant mitral stenosis.

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