Following Mitral Valve Replacement

Transcription

1 Re air of a Subvalvular Le rt Ventricular Aneurysm Following Mitral Valve Replacement Darryl J. Sutorius, M.D., James A. Helmsworth, M.D., James A. Majeski, Ph.D., M.D., and Stephen F. Miller, M.D. ABSTRACT Left ventricular aneurysms are a frequent complication of myocardial infarction. Some aneurysms occur secondary to trauma, previous operation, or infection. This report presents the case of a patient with a posterior submitral left ventricular aneurysm, which occurred following mitral valve replacement. The complete obliteration of the pericardial sac due to previous cardiac operation and the posterior location made external dissection of the aneurysmal wall technically impossible. Closure of the defect through the valve orifice by placing a patch over the neck of the aneurysm was found to be a relatively simple and safe technique combined with replacement of the prosthetic valve. The possibility of injury to the circumflex coronary artery was reduced using this surgical approach. Left ventricular aneurysm is a frequently made diagnosis in the present era of high interest in coronary artery disease and the complications of myocardial ischemia [l-41. There are two types of left ventricular aneurysm not caused by ischemic heart disease. One idiopathic type is limited in occurrence almost exclusively to African Blacks [5]. The other variety, which may be a complication of previous cardiac operation or infection, is not recognized very often [6]. The present report concerns surgical repair of a subvalvular left ventricular aneurysm that occurred after mitral valve replacement. A 51-year-old white woman, who had a history of rheumatic fever as a child, was in good health until she began to experience dyspnea From the Division of Thoracic and Cardiovascular Surgery, Department of Surgery, University of Cincinnati Medical Center, and the Veterans Administration Medical Center, Cincinnati, OH. Accepted for publication June 9, Address reprint requests to Dr. Sutorius, Division of Thoracic and Cardiovascular Surgery, Department of Surgery, University of Cincinnati Medical Center, Cincinnati, OH on exertion and orthopnea. Initially she was treated medically, and there was improvement. Later, however, progressive dyspnea on exertion, occasional paroxysmal nocturnal dyspnea, and orthopnea developed. She had no symptoms of chest pain and no peripheral edema. Chest roentgenogram revealed an enlarged heart with left atrial enlargement. The electrocardiogram revealed atrial fibrillation. Mitral valve replacement was done. A partially calcified mitral valve with fused commissures and a central ostium that measured 1.3 cm was resected. A No. 30 porcine Hancock prosthesis was inserted without difficulty. The patient had an uneventful postoperative course but remained in atrial fibrillation. Five months after operation, the patient experienced some flulike symptoms with a lowgrade fever, increasing shortness of breath, and weight gain of 4.54 kg. She was readmitted to the hospital, and a changing murmur and petechiae were noted. A presumptive diagnosis of bacterial endocarditis was made. The patient's chest roentgenograms demonstrated left ventricular enlargement. Vigorous diuresis resulted in improvement. Cardiac catheterization was performed because of the changing murmur. The prosthetic valve was seen to function well, but the left ventriculogram revealed a hypokinetic left ventricular cavity for an extended period of time (Fig 1). Coronary arteriography revealed the right and left coronary arteries to be normal. The proximal third segment of the circumflex coronary artery appeared to be compressed and stretched by the aneurysm, which was still visible from the ventricular injection (Fig 2). An echocardiogram demonstrated an abnormal area posteriorly and, with the angiographic findings, confirmed the presence of a subvalvular left ventricular aneurysm. The patient underwent reoperation for repair by The Society of Thoracic Surgeons

2 93 Case Report: Sutorius et al: Subvalvular Left Ventricular Aneurysm Fig 1. A lateral view of the left ventriculogram demonstrates the posterior subvalvular aneurysm. Fig 2. Residual contrast medium from the ventricular injection shows the circumflex coronary artery stretched over the aneurysm.

3 94 The Annals of Thoracic Surgery Vol 32 No 1 July 1981 Fig 3. (A) The adhesions from a previous operation make mobilization of the heart difficult. (B) The sagittal view shows the position of the prosthetic valve and the aneurysm. (C) Posteriorly, the aneurysm compressed the circumflex coronary artery. (A = aorta; SVC = superior vena cava; IVC = inferior vena cava; C.V.S. = corona y venous sinus; P.A. = pulmona y arte y; L.V. = left ventn cle.) of the cardiac problem. The initial dissection of the mediastinal structures was difficult due to adhesions from the previous cardiac operation (Fig 3). Cardiopulmonary bypass was employed with intraoperative use of the intraaortic counterpulsation balloon pump. Because of the obliteration of the pericardial sac by vascular adhesions, dissection of the posterior aspect of the left ventricle was not possible. The aneurysm was approached by opening the left atrium and removing the prosthetic mitral valve, which appeared normal. The aneurysm was visible on the posterior wall of the heart in close relation to the mitral ring. There was no thrombus or vegetation present, and there appeared to be a smooth inner surface to the sac. The orifice of the aneurysm was obliterated by sewing a Teflon felt patch to the rim of the aneurysm but the walls of the aneurysm were left in place (Fig 4). A new Hancock mitral valve prosthesis was placed in the mitral valve orifice. The atrium was closed, and cardiopulmonary bypass was discontinued without difficulty. Ventilatory insufficiency developed in the postoperative period requiring tracheostomy and prolonged ventilatory support. During the remainder of the patient s hospital course, progressive improvement was noted. Enteric hyperalimentation was used. An echocardiogram obtained postoperatively demonstrated good left ventricular function. An artifact was noted on the posterior wall from the area of the Tef-

4 95 Case Report: Sutorius et al: Subvalvular Left Ventricular Aneurysm Fig 4. The original prosthetic valve (A) in the mitral position was removed to expose the neck of the aneurysm (B).(C) The Teflon patch was sewn to the neck of the aneurysm and (D) the new mitral valve prosthesis was inserted. (Ao. = aorta; An. = aneurysm; L.V. = left ventricle.) lon patch, which was occluding the mouth of the aneurysm. At the time of discharge, the patient had regained strength and had progressively increased her activities. Three years postoperatively, she could do housework without difficulty. Comment The term ventricular aneurysm was defined by Chesler [71 as a localized protrusion beyond the surface of the free or septa1 walls of the ventricle. Hunter has been given credit for the earliest report of an aneurysm of the ventricle [81. Schlichter and co-workers [8] presented a detailed historical review, which indexes the milestones in the study of ventricular aneurysms. These milestones include a curiosity about the relationship of such aneurysms to myocardial infarction, which led to postmortem examinations for clues to the relationship, and the radiographic discovery of paradoxical pulsation. The causes of subvalvular aneurysms are congenital, traumatic, or mycotic in origin. A rare entity of nonischemic, subvalvular left ventricular aneurysms was identified by Abrahams and colleagues [51 and has been well documented in Nigerians and in the South African Bantu [9]. Idiopathic subvalvular aneurysms can occur in both the subaortic and submitral position, the latter being most common. The clinical presentation is one of heart failure, angina, systemic emboli, and aortic or mitral incompetence. Abrahams and co-workers [5] and Chesler [7] supported the concept that idiopathic subvalvular aneurysms occur only under those portions of the aorta and mitral valve an-

5 96 The Annals of Thoracic Surgery Vol 32 No 1 July 1981 nulus that are directly related to the epicardium and where there is a muscular fibrous junction, an area of potential weakness. Diagnostic clues can be obtained by physical examination, chest roentgenograms, electrocardiograms, and echocardiograms. Left cineventriculography can confirm the diagnosis. Our patient demonstrated an unusual subvalvular ventricular aneurysm well documented on both the cardiac catheterization study and echocardiogram (see Fig 1). Coronary arteriography showed no coronary occlusion; however, there was an area where the circumflex coronary artery was narrowed as if stretched over the aneurysm (see Fig 2). McVaugh and associates [61 reported a similar case in which the patient previously had had a mitral valve replacement. They proposed that the cause of the aneurysm in their patient was operative injury to the posterior wall of the ventricle at the time of excision of a densely calcified mitral valve. Our observations support their hypothesis. All cases of subvalvular aneurysm present a difficult problem of surgical exposure since the subvalvular position is not easily approached from the external surface. The circumflex coronary artery can be inadvertently ligated during repair [9]. Waldenhausen and co-workers [lo], using an original approach, gained exposure by dividing the pulmonary artery. From these reports and our own experience, several points are evident. The diagnosis must be suspected, and ventriculograms of good quality must be obtained. With this information, the optimal surgical approach can be determined. In our patient, complete obliteration of the pericardial sac due to previous operation and the posterior location of the subvalvular aneurysm made intrapericardial dissection of the aneurysm technically impossible (see Fig 3). Closure of the mouth of the aneurysm through the valve orifice by suturing a patch over the neck of the aneurysm proved to be a reliable surgical approach that can readily be combined with replacement of the prosthetic valve (see Fig 4). The possibility of injury to the circumflex coronary artery was reduced using this approach. References 1. Diethrich EB, Koopot R, Kinard SA: Pseudoaneurysm of atrioventricular groove: a late complication of mitral valve replacement. J Thorac Cardiovasc Surg 74:47, Loop FD: Ventricular aneurysmectomy. Surg Clin North Am 51:1071, Loop FD, Effler DB, Navia JA, et al: Aneurysms of the left ventricle: survival and results of a tenyear surgical experience. Ann Surg 178:391, Najafi J, Dye WS, Javid H, et al: Current surgical management of left ventricular aneurysm. Arch Surg 110:1027, Abrahams DG, Barton CJ, Cockshot WP, et al: Annular subvalvular left ventricular aneurysms. Q J Med 31:345, McVaugh H, Joyner CR, Pierce WS, Johnson J: Repair of subvalvular left ventricular aneurysm occurring as a complication of mitral valve replacement. J Thorac Cardiovasc Surg 58:291, Chesler E: Aneurysms of the left ventricle. Cardiovasc Clin 4:187, Schlichter J, Helberstein HK, Katz LN: Aneurysm of the heart: a correlative study of 102 proved cases. Medicine (Baltimore) 33:43, Chesler E, Joffe N, Schamroth L, Myers A: Annular subvalvular left ventricle aneurysms in the South African Bantu, Circulation 3243, Waldhausen JA, Petry EI, Kurlander GJ: Successful repair of subvalvular annular aneurysm of the left ventricle. N Engl J Med 275:984, 1966