Cardiac Case Study August-September 2006
Balloon Valvuloplasty in an Adult with Critical Aortic Stenosis
By Vasilis Babaliaros MD, associate director, Emory Center for Valvular Intervention and Structural Heart Disease, and Peter Block, MD, FACC, director, Emory Center for Valvular Intervention and Structural Heart Disease
Degenerative disease of the aortic valve occurs with age, often in those older than 70. However, patients with additional valve pathology (bicuspid aortic valves or rheumatic valvular disease) can present much earlier in life with deterioration of valve function and consequent symptoms. The most common symptoms of aortic stenosis are chronic heart failure, syncope, and angina.
Whereas most patients can benefit from surgical aortic valve replacement, approximately 30 percent of patients are ineligible for surgery because of their high-risk status (advanced age, multiple co-morbidities, and end-stage disease). For these patients, balloon aortic valvuloplasty (BAV) has been a palliative procedure. In patients with cardiogenic shock, pharmacologic support is ineffective, and BAV is life-saving.
Such was the case for an 81-year-old male with a history significant for critical aortic stenosis, heart failure, myelodysplastic syndrome, chronic renal insufficiency, and hypothyroidism who presented with dyspnea to an outside hospital in April 2005. He was admitted with a diagnosis of heart failure and was treated for several days with little improvement. He was transferred to Emory University Hospital for further treatment of heart failure and aortic stenosis.
The patient had been followed for several years by outside physicians for aortic stenosis and experienced multiple episodes of heart failure. Because of his age and pre-existing co-morbidities, this patient was not considered a candidate for surgical valve replacement because of unacceptable associated morbidity and mortality.
On arrival, the patient appeared debilitated. His heart rate was 95 BPM, and his blood pressure was 85/60 mmHg. Jugular venous pressure was estimated over 10cm/H20. The patient’s oxygen saturation was 90 percent on 2 liters of oxygen. A loud systolic murmur was heard over the upper right sternal border. Mild crackles were heard posteriorly with inspiration. His blood work was significant for platelets of 30,000/IL and creatinine of 3.1 mg/dL.
Ultrasound echocardiography measured an aortic valve area of 0.5 cm2 with a mean gradient of 54 mmHg. The left ventricular ejection fraction was 35 percent, and the right ventricular function was moderately to severely depressed. The aortic valve was heavily calcified as was the mitral annulus. Moderate mitral regurgitation and aortic regurgitation were present. Chest x-ray showed bilateral opacities consistent with pulmonary edema and pleural effusions.
The patient was admitted to the intensive care unit with ionotropic (dobutamine drip) and vasopressor support. Despite pharmacologic intervention, the patient’s blood pressure continued to drop and the patient became somnolent. The patient was taken emergently to the catheterization laboratory with a systolic blood pressure of 70 mmHg.
Balloon Aortic Valvuloplasty
Arterial and venous access were obtained. A temporary pacing catheter was placed in the right ventricle, and subsequently a stiff guide wire was placed from the aorta, across the aortic valve, and into the left ventricle. A 20 mm balloon was advanced over this wire and across the aortic valve. During rapid ventricular pacing (200 BPM), the balloon was inflated to maximal size. The inflation was repeated, and the mean gradient across the aortic valve decreased by 50 percent (from 30 to 15 mmHg as measured at catheterization). After the second inflation, the patient awakened and was able to report amelioration of symptoms. Because of pre-existing aortic insufficiency, a larger balloon dilation was not attempted.
Despite significant improvements in hemodynamics and renal function (creatinine decreased to 1.7mg/dL), the patient required continuous support with low-dose dobutamine. Repeat ultrasound showed an aortic valve area of 0.7 cm2 with aortic insufficiency unchanged from the initial echocardiogram. A decision was made to take the patient back to the catheterization laboratory for a repeat BAV. A 23 mm balloon was inflated across the aortic valve and the subsequent gradient improved significantly to 6 mmHg, and his aortic valve area increased to 0.9 cm2. The patient was discharged a few days later much improved and dobutamine was discontinued.
Future Directions
Currently, a novel technique is being studied to address the issue of re-stenosis after BAV. To date, more than100 heart valves have been placed percutaneously for compassionate use in patients with critical aortic stenosis. Initial studies in France have demonstrated feasibility and ongoing work in Vancouver, Canada is refining the technique to improve outcomes. U.S. trials are already under way, and the anticipated start date for percutaneous valve implantation at Emory University is early 2007. In the interim, patients are being referred to Emory for inclusion in this trial and other protocols (ie, the RADAR trial – a multi-center study for BAV followed by radiation to prevent re-stenosis). While awaiting these better options, patients are being temporized with one or more aortic valvuloplasties. Certainly, the future treatments for valvular heart disease will continue to progress with increasing possibilities for high-risk or inoperable patients.
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References:
- Block, P.P., I. Clinical and hemodynamic follow-up after percutaneous aortic valvuloplasty in the elderly. Am J Cardiol 1988;62:760-763.
- Cribier, A.E., Tron, H., Bauer, C., et al. Treatment of calcific aortic stenosis with the percutaneous heart valve. J Am CollCardiol 2006;47:1214-1223.
- Webb, J.G., Chandavimol, M., Thompson, C.R., et al. Percutaneous aortic valve implantation retrograde from the femoral artery. Circulation 2006;113:842-850.
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