Bicuspid aortic valve

Calcific embolization from aortic stenosis may be more frequent than commonly appreciated. Most calcific emboli are clinically silent, although transient ischemic attacks, cerebral infarcts, blindness (from central retinal artery occlusions), and myocardial infarctions have been reported. We describe a patient with calcific bicuspid aortic stenosis who presented with transient ischemic attacks and angina secondary to a calcific embolus to the second circumflex marginal coronary artery. The calcific embolus was retrieved during aortic valve replacement surgery. A review of the literature suggests that calcific embolization from calcific aortic stenosis may occur more commonly in patients with bicuspid valves.

While calcific aortic stenosis can result in multiple hemodynamic alterations and cardiac symptoms, it can sometimes present with symptoms related to vascular insufficiency due to calcific embolization.[1-5] These symptoms may provide the indication for surgical replacement of the valve even in the absence of severe valvular stenosis or symptoms of syncope, congestive heart failure, or angina.[1-3] We describe a patient with severe calcific bicuspid aortic stenosis, exertional angina, and transient ischemic attacks (TIAs), who had documented calcific embolization to a coronary artery.

CASE REPORT

A 45-year-old man with a history of a heart murmur since childhood presented to the Neurology Service with complaints of left-sided weakness and imbalance. The symptoms completely resolved by the time of presentation. Neurologic workup, including computed tomographic (CT) scan and magnetic resonance imaging (MRI) of the head as well as carotid duplex studies, was essentially normal. The patient denied any symptoms of congestive heart failure or frank syncope. He had a history of coarctation repair at the age of 19 years and in the past few years had experienced dull substernal chest pain radiating to the throat and associated with exertion. Physical examination was remarkable for delayed carotid pulse, decreased [A.sub.2] and a late peaking grade 4/6 systolic ejection murmur at the base. A grade 2 to 3/6 diastolic blow at the left sternal border was also noted. The ECG revealed normal sinus rhythm with a left anterior hemiblock and T-wave inversions in [V.sub.4] to [V.sub.6].

An echocardiogram revealed a calcified bicuspid aortic valve with decreased excursion, moderate aortic insufficiency, and a dilated aortic root. An aortic valve gradient of 42 mm and an aortic valve area of 0.7 [cm.sub.2] were obtained.

At cardiac catheterization, normal right-sided pressures were noted. Attempts to cross a severely calcified aortic valve with multiple catheters failed. Coronary arteriography revealed a calcific filling defect at the bifurcation of a large second obtuse marginal branch of the left circumflex artery that resulted in an approximate 70 percent stenosis (Fig 1). No other coronary artery disease was noted. A 3+ aortic insufficiency and a dilated and aneurysmal ascending aorta were seen during aortic root injection.

In light of the clinical and echocardiographic evidence of severe aortic stenosis associated with symptoms of angina and transient ischemic attacks, as well as evidence of calcific embolization from the aortic valve, the patient underwent aortic valve replacement with a 25-mm aortic homograft. The ascending aorta was also replaced with a 38-mm Dacron interposition graft. The removal of the large calcific embolus, adherent to the intima of the second obtuse marginal artery, required a localized endarterectomy. The vessel was patched with a saphenous vein bypass graft from the aorta. The patient tolerated surgery without complications. He is symptom free 20 months after surgery. Examination of the aortic valve revealed a raw area on the ventricular surface of the valve that, most likely, was the site for calcium breakage and embolization (Fig 2).

DISCUSSION

The first report of calcific embolization from calcific aortic stenosis was described by Moragues and associates[6] in 1950. Holly and coworkers[7] from the Mayo Clinic reported their observations of spontaneous calcific embolization in 31 of 165 autopsy cases with calcific aortic stenosis. Of these, 10 patients (6 percent of the total) had major coronary emboli (with a size of 1 to 3 mm). Soulie and associates[8] reported 28 cases of spontaneous calcific emboli in 81 patients with calcific aortic stenosis. This incidence was twice that observed with calcific mitral disease. The frequency of macroscopic coronary embolization exceeded 20 percent in the whole series (18 of 81 patients).

Over the past two decades, few reports have been published describing patients who suffered clinical sequelae of spontaneous calcific embolization from calcific aortic stenosis. Patients were described with clinical evidence of cerebral emboli resulting in strokes[1] or TIAs[3,4] and emboli to the central retinal artery,[2] but no other explanation for these symptoms. One report[5] described a patient with calcific aortic stenosis who presented with an inferolateral myocardial infarction and obstruction of a distal branch of the left circumflex artery that was suspected but not proven to be secondary to embolization from the aortic valve. Angina in a patient with calcific aortic stenosis is more commonly related to the presence of atherosclerotic coronary artery disease. However, calcific embolization should be considered as the likely cause if the patient presents with sudden onset of chest pain. Our patient had stable angina and TIAs and was proven to have spontaneous coronary embolization resulting in narrowing of the marginal coronary artery noted on angiography. Other reports in the literature describe calcium emboli from stenotic aortic valves associated with cardiac catheterization[9-11] or percutaneous balloon valvuloplasty[12,13] resulting in cerebral infarctions,[9,12] myocardial infarctions,[11-13] or leg ischemia.[10] In the latter case, the embolus was surgically retrieved from the left femoral artery.

It has been suggested[12] that patients with calcific emboli have a higher incidence of bicuspid aortic valve,[2,4,11,12] but this was not examined in either of the two large autopsy studies.[7,8] Other authors[1,5] have suggested that aortic insufficiency may increase the likelihood of spontaneous calcific embolization. Calcific embolization is probably related to the amount of calcium deposited on the valves, but not necessarily dependent on the hemodynamic severity of aortic stenosis.[1,2] This is an important consideration since some patients who may not be surgical candidates based on cardiac symptoms may be advised surgery if they have clinical evidence suggestive of embolization.[1,3,4] Our patient would have been considered for surgery because of his cerebral symptoms even in the absence of angina.

As shown in Figure 2, the raw area of the undersurface of the excised aortic valve appeared to be the most likely source for the coronary embolus. This may be related to the extremely high intraventricular pressure during systole in the patient with severe aortic stenosis causing fracture of a piece of calcium which in the presence of concomitant aortic insufficiency resulted in embolization.[1,5]

We replaced the aortic valve in our patient with a homograft aortic valve. Clearly, homograft valve is as good, if not superior to other valves in that it has the added advantage of avoiding anticoagulation, as well as, long-term durability.[14] Unlike other valve substitutes, the homograft valves are not readily available for use in all sizes. Partly because of lack of adequate ascending aorta on the homograft and partly because of concern about homograft aortic wall calcification,[15] we replaced the ascending aorta with a Dacron graft.

Calcific embolization from calcific aortic stenosis is probably an underestimated phenomenon. It should be taken into consideration whenever patients with aortic stenosis present with symptoms of vascular insufficiency.

REFERENCES

[1] Rancurel G, Marelle L, Vincent D, Catala M, Arzimanoglou A, Vacheron A. Spontaneous calcific cerebral embolus from a calcific aortic stenosis in a middle cerebral artery infarct. Stroke 1989; 20:691-93

[2] Brockmeier LB, Adolph RJ, Gustin BW, Holmes JC, Sacks JG. Calcium emboli to the retinal artery in calcific aortic stenosis. Am Heart J 1981; 101:32-7

[3] Jabbari B, Lawrence PJ, Huott AD. Aortic stenosis and calcific cerebral embolization. Md State Med J 1980; 29:33-4

[4] Martin GJ, Moran JM, Lesch M. Neurologic symptoms from calcific microemboli in aortic stenosis. Am Heart J 1981; 102:471-72

[5] Mansur AJ, de Miranda RC, Grinberg M, Bellotti G, Pileggi F. Calcific aortic stenosis presenting as acute myocardial infarction. J Cardiovasc Surg 1990; 31:310-12

[6] Moragues V, Bawell MB, Shrader EL. Coronary embolism: review of the literature and report of a unique case. Circulation 1950; 2:434-37

[7] Holley KE, Bahn RC, McGoon DC, Mankin HT. Spontaneous calcific embolization associated with calcific aortic stenosis. Circulation 1963; 27:197-202

[8] Soulie P, Caramanian M, Soulie J, Bader JL, Colcher E. Les embolies calcaires des atteintes orificielles calcifees du coeur gauche. Arch Mal Coeur 1969; 12:1657-84

[9] Kapila A, Hart R. Calcific cerebral emboli and aortic stenosis: detection of computed tomography. Stroke 1986; 17:619-21

[10] Yacoub MH, Lise M, Balcon R. Total occlusion of the left femoral artery by a calcium embolus from a heavily calcified aortic valve. Am J Cardiol 1970; 25:359-61

[11] Arvidsson H, Parker BM, Burford TM. Coronary artery occlusion, a complication of thoracic aortography in a patient with calcific aortic stenosis. Am J Cardiol 1962; 10:115-19

[12] Davidson CJ, Skelton TN, Kisslo KB, Kong Y, Peter RH, Simonton CA, et al. The risk for systemic embolization associated with percutaneous balloon valvuloplasty in adults. Ann Intern Med 1988; 108:557-60

[13] Deligonul U, Kern MJ, Bell ST, Gabliani G, Labovitz A, Vandormael M. Acute myocardial infarction during percutaneous aortic balloon valvuloplasty. Cathet Cardiovasc Diagn 1988; 15:164-68

[14] O'Brien MF, Stafford G, Gardner M, Pohlner P, McGiffin D, Johnston N, et al. The viable cryopreserved allograft aortic valve. J Cardiac Surg 1987; 2(suppl): 153-67

[15] Clarke DR. Extended aortic root replacement with cryopreserved allografts: do they hold up? Ann Thorac Surg 1991; 52:669-75

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