myocardial infarction is unusual in these patients without accompanying coronary arteriosclerosis.

Transcription

1 AORTIC STENOSIS AND TRANSMURAL MYOCARDIAL INFARCTION WITHOUT CORONARY ARTERY DISEASE A CASE REPORT AND DISCUSSION* MARTIN DUKE, M.D., F.I.C.A., AND JOHN R. EDDY, M.D. In view of current advances in cardiac surgery, the combination of coronary artery disease and aortic valve stenosis needs careful preoperative evaluation. Although myocardial fibrosis can be associated with an aortic valve lesion, transmural myocardial infarction is unusual in these patients without accompanying coronary arteriosclerosis. 1 A patient with severe aortic stenosis and a transmural myocardial infarction without coronary artery disease will be presented. The literature on this subject will be > reviewed. CASE REPORT A 59-year-old man was hospitalized with exertional chest pain, dyspnea and paroxysmal nocturnal dyspnea observed for 5 months. Nitroglycerin and rest usually relieved the chest symptoms in 3 to 4 min. Past history was significant for a heart murmur first described during an insurance examination 15 years previously. There was no history of rheumatic fever. On physical examination principal findings consisted of a blood pressure of 98/80, weak peripheral pulses, n grade 1 apical systolic murmur, a grade 2 to 3 aortic systolic murmur extending towards the neck, and decreased intensity of the second sound in the aortic area. Chest x-ray revealed enlargement of the left ventricle and extensive aortic valve calcification. Electrocardiogram showed a left bundle branch block pattern. The diagnosis of aortic valve stenosis was made and the patient placed on effective diuretic therapy. Two months later cardiac catheterization and coronary arteriography were performed (table 1). The mean aortic systolic gradient was 49 mm Hg with a calculated aortic valve area of 0.5 cm.2 The left ventricular end diastolic pressure was elevated to 32 mm Hg. No mitral valve gradient was seen. Left ventricular angiogram showed dilation and poor systolic emptying of the left ventricle. Coronary arteriography revealed a right dominant distribution with no evidence of intrinsic disease of the right coronary artery. A few minor irregularities without occlusion or obstruction were seen in the small circumflex branch of the left coronary artery. The left anterior descending branch also showed no segmental narrowing. Aortic valve surgery was scheduled. However, 1 month later the patient developed pressure in the chest lasting about 2.5 hr, lightheadedness, increasing * From Departments of Cardiology and Medicine, Manchester Memorial Hospital, Manchester, Conn. Sponsored in part by a grant from the Gertrude H. Rogers Fund. 265

2 266 Cardiac output, per min. per m2. TABLE 1 Cardiac catheterization results cough and dyspnea. He was immediately hospitalized. Blood pressure was 96/80 heart rate was 110 per min and regular, neck veins were slightly distended, and the heart murmur was unchanged. A few rales were heard in both axillae and lung bases. Electrocardiograms still showed left bundle branch block, although serial tracings revealed transient T-wave and ST changes in AVL and precordial chest leads. Multiple ventricular premature beats were also noted for a brief period. Serum glutamic-oxaloacetic transaminase on the first 3 hospital days was 12, 68 and 45 units (normal, 0 to 40 units). Lactic acid dehydrogenase on the 2nd and 3rd days was 185 and 160 units (normal, 0 to 125 units) and on the 4th day 480 units (normal, 0 to 350 units). Creatine phosphokinase was 4 units and 23 units on the 1st and 2nd day, respectively (normal, 0 to 12 units). The diagnosis of myocardial damage and congestive heart failure was made. Aortic valve surgery was deferred and treatment started writh digitalis, diuretics and anticoagulants. There was initial improvement, but 2 months later the patient was rehospitalized, complaining of increasing shortness of breath, chest pain and loss of appetite. Cyanosis was present with other physical findings as previously described. It was felt that he was in chronic congestive heart failure with an extremely low cardiac output secondary to both aortic valve obstruction and myocardial failure. His condition worsened in spite of therapy, and he expired 1 1 days later. At postmortem examination the heart weighed 660 gm. The right and left ventricular walls averaged 0.3 cm and 1.7 cm thick, respectively. The aortic valve consisted of two irregularly calcified rigid nodular cusps with a slitlike opening measuring 0.2 cm in its greatest diameter. The posterolateral left ven-

3 267 FIG. 1. A large myocardial infarction occupying the entire thickness of the posterolateral wall of the left ventricle is seen. Arrow, calcified aortic valve. tricular wall contained a transmural myocardial infarct (5 by 6 cm) measuring 1 cm thick (fig. 1), which on microscopic examination showed extensive fibrous tissue replacement, a few lymphocytes and one small area of polymorphonuclear leukocyte infiltration. An additional small area of fibrosis was noted at the apex. The endocardium beneath the aortic valve was gray-white and slightly thickened. The right and left coronary ostia were patent and not occluded by the heavy calcific deposits on the aortic valve. A small atheromatous plaque was present at the level of the bifurcation of the left coronary artery into the left circumflex and anterior descending branches. The lumen was not narrowed. The left circumflex artery was short with no pathologic changes. The left anterior descending artery and right coronary artery were normal save for a few minute areas of atheromatous change in the intima without compromise of the lumen. The final anatomical diagnosis was calcific aortic stenosis with cardiomegaly, myocardial infarction of the posterolateral wall and apex, acute congestion of the liver, chronic passive congestion of the lungs with bilateral pleural effusions and an incidental finding of islet cell adenoma of the pancreas. DISCUSSION The clinical findings in this patient were typical of aortic stenosis. The transient electrocardiographic changes in the presence of left bundle branch block, the small rise in the serum enzymes, and the clinical picture at the time of the second

4 268 hospitalization, were highly suggestive of myocardial damage. The patient died before aortic valve surgery could be performed. Autopsy examination confirmed the presence of severe calcific aortic stenosis and an extensive transmural myocardial infarction without coronary occlusion, narrowing, or significant arteriosclerosis. Documentation of aortic stenosis and transmural myocardial infarction without coronary artery disease is not readily found. Indeed, Anderson stated that electrocardiographic evidence of myocardial necrosis in patients with aortic stenosis suggests the presence of occlusive coronary artery disease. Friedberg and Horn2 described eight patients with calcific aortic stenosis and myocardial infarction, two of whom presented absent or only slight coronary artery narrowing. The remaining patients had moderate to severe coronary vascular disease without recent coronary occlusions. Bergeron et al.3 described old myocardial infarctions without evidence of coronary occlusions in 19 of 100 patients with pure aortic stenosis. However, in only two patients were coronary arteriosclerotic changes absent. In 107 patients with aortic stenosis, Kumpe and Bean4 found scars of old myocardial infarctions in 14, all of whom had from mild to severe coronary arteriosclerosis. Horan and Barnes5 reported coronary sclerosis in 100 cases of aortic stenosis, the degree of sclerosis varying inversely with the degree of aortic stenosis. Aside from narrowing due to arteriosclerosis, there are other ways in which coronary vessles in calcific aortic stenosis might become occluded.6 Calcium deposits may obstruct the ostia of the coronary vessles in the sinuses of Valsalva. In addition, a calcium particle or a septic embolus from bacterial endocarditis can lodge in a coronary artery. Neither process was present in this case. Variations in coronary artery anatomy may also contribute to an insufficient blood supply to areas of the myocardium. Dissolution of a coronary embolus can occur, without anatomical findings of the embolus at autopsy. Angina pectoris with aortic stenosis represents an inadequate coronary blood flow in the presence of increased requirements of a hypertrophied and overworked heart, a relative perfusion deficit. With the added burden of coronary arteriosclerosis, it is readily understood how these increased demands might more easily produce a spectrum of findings ranging from angina pectoris to myocardial fibrosis, and to the extreme represented by myocardial infarction. In the absence of coronary artery disease, however, the latter represents an extreme disparity between the demands of the heart and the ability of normal coronary vessels to supply these demands. DeSanctis has pointed out that myocardial infarction should only be considered as due to aortic stenosis per se if valvular obstruction is extremely severe. In addition, since the subendocardial region is the most poorly perfused, a myocardial infarct without coronary artery disease would usually occur in this area and would rarely, if ever, be transmural.1 A predilection for papillary muscle infarction has been reported in the presence of left ventricular hypertrophy without associated coronary atherosclerosis.8 With the advent of aortic valve and coronary artery surgery, the presence and location of myocardial infarction with or without coronary artery disease has

5 _ 269 become even more important. Careful preoperative assessment of the myocardium and its function via cardiac catheterization and left ventriculography, together with close perusal of the coronary vessels by coronary arteriography, might help determine whether both aortic valve surgery and a myocardial revascularization procedure are indicated. Whether the relative myocardial perfusion deficit of aortic stenosis and left ventricular hypertrophy without coronary artery disease can encourage the growth of collateral circulation from a revascularization procedure remains unanswered. SUMMARY Severe aortic valve stenosis, normal coronary arteries and an extensive transmural myocardial infarction are described in a 59-year-old man. This combination has been reported infrequently. It emphasizes, however, the need for careful evaluation of the aortic valve obstruction and the patency of the coronary arteries so that specific and appropriate surgical procedures can be planned. ACKNOWLEDGMENTS The cardiac catheterization and angiogram were performed at the Cardiorespiratory Laboratory, Hartford Hospital. The autopsy was performed by Boris Vira, M.D., Manchester Memorial Hospital. Martin Duke, M.D., F.I.C.A. Manchester Memorial Hospital 71 Haynes Street Manchester, Conn REFERENCES 1. Anderson, M. W.: The clinical course of patients with calcific aortic stenosis. Mayo Clin. Proc. Staff Meet., 36 : 439, Friedberg, C. K., and Horn, H.: Acute myocardial infraction not due to coronary artery occlusion. J.A.M.A., 112: 1675, Bergeron, J., Abelmann, W. H., Vasquez-Milan, H., and Ellis, L. B.: Aortic stenosis clinical manifestations and course of the disease. Arch. Int. Med., 94: 911, Kumpe, C. W., and Bean, W. B.: Aortic stenosis: a study of the clinical and pathologic aspects of 107 proved cases. Medicine, 27: 139, Horan, M. J., Jr., and Barnes, A. R.: Calcareous aortic stenosis and coronary artery disease. Am. J. M. Sc., 215: 451, Braunwald, E., Roberts, W. C., Goldblatt, A., Aygen, M. M., Rocket, S. D., and Gilbert, J. W.: Aortic stenosis: physiological, pathological and clinical concepts. Ann. Int. Med., 58: 494, DeSanctis, R. W.: Questions and answers can aortic stenosis cause myocardial infarction? J. A. M. A., 205: 58, Layman, T. E., Coleman, J. B., Karnegis, J. N., and Edwards, J. E.: Recurrent cardiac failure associated with calcified aortic valve. Minnesota Med., 49: 1143, 1966.