Acute Aortic Regurgitation Secondary to Aortic Dissection

Transcription

1 Acute Aortic Regurgitation Secondary to Aortic Dissection Surgical Management Without Valve Replacement Hassan Najafi, M.D., William S. Dye, M.D., Hushang Javid, M.D., James A. Hunter, M.D., Marshall D. Goldin, M.D., and Ormand C. Julian, M.D. ABSTRACT Emergency operations were performed in 7 adult patients for severe aortic insufficiency caused by acute aortic dissection. Dissection beginning in the aortic root involved the entire thoracoabdominal aorta in at least 3 patients. The operative findings consisted of an arch of relatively normal caliber, supravalvular intimal tear, circumferential dissection, and prolapse of the aortic cusps into the left ventricle. Repair of the proximal dissected layers and elevation of the cusps to their normal position restored valve competence in every patient. Six survivors have retained normal aortic valve function four months to six years postoperatively. The review emphasizes the feasibility of restoring aortic valve competence without using a valve substitute in treating aortic insufficiency caused by acute aortic dissection. S evere aortic insufficiency is an extremely serious complication of acute aortic dissection and constitutes a major cause of death in these patients [5]. In aortic arch dissection the lesion is usually initiated by a transverse intimal tear in the ascending aorta immediately superior to the aortic valve. Retrograde extension of the dissection results in displacement of the aortic cusps into the left ventricle causing aortic valve incompetence. More than 70% of the patients in this particular group die of intrapericardial rupture and cardiac tamponade [5]. Fortunately, in the majority of instances there is sufficient time to make the diagnosis and to institute surgical therapy. This report demonstrates the effectiveness of early operative treatment in 7 patients with acute aortic regurgitation secondary to aortic dissection and emphasizes the feasibility of restoring valve competence without using a valve substitute. Clinical Experience Our group consists of 7 patients, 6 men and 1 woman, whose ages ranged from 35 to 56 years with a mean age of 47 years. The common clin- From the Department of Cardiovascular-Thoracic Surgery, Rush-Presbyterian-St. Luke s Medical Center and Rush Medical College, Chicago, Ill. Supported in part by U.S. Public Health Service Grant T12-He Presented at the Eighth Annual Meeting of The Society of Thoracic Surgeons, San Francisco, Calif., Jan. 2426, Address reprint requests to Dr. Najafi, 1725 W. Harrison, Chicago, Ill THE ANNALS OF THORACIC SURGERY

2 Aortic Regurgitation from Dissection ical features consisted of excruciating chest or intrascapular pain associated with prostration and anxiety but without significant shortness of breath. None of the patients had been known to have a heart murmur. There was no history of rheumatic fever, trauma, or infection. All patients were examined within several hours of the onset of the pain. Signs of aortic insufficiency appeared shortly thereafter. This was followed by symptoms of cardiac decompensation and signs of congestive heart failure intractable to medical treatment. The interesting feature in the majority was the absence of significant cardiomegaly in spite of marked aortic insufficiency and massive heart failure. The electrocardiogram did not show myocardial infarction in any of the patients. The specific clinical features consisted of hypertension in 3 patients, acute iliac artery occlusion in 2, electrocardiographic evidence of myocardial ischemia in 1, and signs of pericardial tamponade in 2 patients. The only woman in the group had suffered a brief episode of unconsciousness shortly after the onset of her chest pain and on examination showed evidence of abnormal brachiocephalic pulsations. Diagnosis of aortic dissection causing aortic insufficiency was made on clinical grounds in all 7 patients. In the single patient with electrocardiographic evidence of myocardial ischemia, the possibility of left coronary artery dissection was entertained and proved at operation. Five patients had a retrograde aortogram preoperatively. In 4 it showed the dissecting process and confirmed the presence of aortic insufficiency (Fig. 1). In 1 patient, two separate injections of contrast medium in the ascending aorta failed to show the dissection (Fig. 2). Emergency opera- FIG. 1. Aortic root injection of contrast medium demonstrating aortic regurgitation and type I dissection beginning in the proximal ascending aorta and extending into the abdominal aorta. VOL. 14, NO. 5, NOVEMBER,

3 NAJAFI ET AL. FIG. 2. Normal aortogram in a patient with dissection of the entire ascending aorta. tion in this patient was carried out on the basis of certainty of the clinical diagnosis and because of intractable congestive heart failure. This patient had localized dissection of the ascending aorta with hemopericardium and extension of the dissection around the initial portion of the right coronary artery. According to the classification by DeBakey, 3 patients suffered type I dissection with the process beginning in the aortic root and terminating in one of the iliac arteries; in 2 patients the dissection. was confined to the ascending aorta, type 11; and in the remaining 2 the distal extension of the dissection remains obscure. Operation was performed within several hours to several days from the onset of the pain. Surgical Considerations Because of extremely poor cardiac performance in 2 patients, partial bypass through the common femoral vessels was instituted under local anesthesia before the heart was exposed. In 3 others, similar preparations for cardiac assist were made under local anesthesia, but perfusion was not instituted until after completion of cannulation for total bypass [lo]. In the first patient with type I dissection (the only woman in the group), the operation consisted of replacement of the entire aortic arch with a woven Dacron tube graft to which the three brachiocephalic arteries were anastomosed. Hypothermia of approximately 15 C. was employed to prevent brain damage. She maintained good cardiac output and showed no evidence of aortic insufficiency postoperatively. The patient did not awaken, and death due to massive brain hemorrhage occurred 48 hours after operation. In the remaining 6 patients the repair consisted of transection of the ascending aorta and obliteration of the false lumen by suture approximation of the dissected layers both proximally and distally, followed by either a primary anastomosis 476 THE ANNALS OF THORACIC SURGERY

4 Aortic Regurgitation from Dissection (4 patients) or graft replacement of the ascending aorta (2 patients). Median sternotomy provides excellent exposure. The repair was done with the patient on total bypass and the ascending aorta clamped proximal to the innominate artery. It was considered imperative to perfuse the coronary arteries because of already poor ventricular compliance and total heart failure, which actually constituted the indication for operation. Certain aspects of the procedure are of sufficient importance to be elaborated here. The initial incision in the aorta should be a transverse aortotomy immediately superior to the aortic valve. This incision usually coincides with the level of the intimal tear. Vertical aortotomy should be avoided since in a large percentage of these patients, particularly in the early stage of the disease, it is possible to avoid graft replacement of the ascending aorta. Often it is necessary to transect the ascending aorta completely at the level of the initial aortotomy. The operative findings in these patients consisted of an ascending aorta of nearly normal caliber and a sizable intimal tear superior to the aortic valve with circumferential dissection. The dissection extended to the valve annulus in every patient. In 1 patient the left coronary artery was dissected, although still in continuity with its orifice, and in another patient the right coronary artery was similarly dissected. In both of these patients it was possible to perfuse the arteries. In the latter patient a dissecting hematoma was present in the atrioventricular groove extending to the diaphragmatic aspect of the heart. The aortic annulus was of normal size in every patient. The aortic insufficiency had been caused by downward displacement of normal aortic cusps into the left ventricle. Aortic valve competence was restored by elevating the prolapsed cusps to their normal position by reapproximating the dissected layers [131. The repair, as shown in Figure 3, is carried out with simple over-and-over sutures, passing the needle from outside into the aortic lumen and taking somewhat deeper sutures in the inner dissected layers. These maneuvers result in eversion of the intima so that subsequently, when the aorta is reanastomosed or when a graft is used to replace the ascending aorta, the second suture line excludes the first suture line and reinforces the intima (see Fig. 3). This reduces the possibility of recurrence of the dissection. An alternative method reported in the literature describes the use of Teflon pledgets inside the aortic lumen to prevent cutting of the sutures through the intima [l]. We believe the method described here avoids the use of Teflon within the aortic lumen while accomplishing the same purpose. In 2 patients, because of the precarious quality of the adventitia, the ascending aorta was replaced with a woven Dacron tube graft. The postoperative course was uneventful in 5 patients. One patient in whom the entire aortic arch was replaced remained comatose and in spite of excellent cardiac performance died 48 hours after operation. Another patient developed severe hypertension which was vigorously treated for fear of recurrence of intimal tear. The 6 survivors have maintained normal aortic valve VOL. 14, NO. 5, NOVEMBER,

5 NAJAFI ET AL. FIG. 3. The intimal tear with downward displacement of the aortic cusps (A), circumferential dissection (B), repair of the dissected layers (C), and graft replacement W) or primary anastomosis of the divided ascending aorta (E). function during the follow-up period of four months to six years. Three patients have had a postoperative aortogram that confirmed the competence of the aortic valve and the stable nature of the dissection. Comment Acute dissection of the aortic arch is an extremely lethal event, causing death in the majority of patients within a few hours or days after onset. Severe aortic insufficiency caused by retrograde extension of dissection is a major cause of death in these patients. More than 70% of the patients in this particular group die as a result of pericardial rupture and cardiac tamponade. Fortunately, the majority live long enough for the diagnosis to be established and therapy instituted. The improvement in accuracy of diagnosis has been stimulated in part by the greater awareness of this entity and by the increasing number of successful operative results reported in the literature [l, 2, 4, 6, 7, 10, 12, 141. Retrograde aortography is essential when aortic dissection is suspected. When the clinical diagnosis is certain, however, and the patient s life is threatened by massive and intractable congestive heart failure, immediate surgical treatment becomes essential. Two patients in this series would have died if the operation had been delayed because of angiography. These 2 terminal patients in profound failure were admitted to the operating room on their arrival at the hospital, and cardiopulmonary bypass was instituted 478 THE ANNALS OF THORACIC SURGERY

6 Aortic Regurgitation from Dissectzon within one hour. In these patients, not only was the diagnosis certain but also the extent of the dissection was obvious. Both patients developed acute aortic insufficiency shortly after the onset of unremitting chest pain followed by abrupt unilateral iliac occlusion. In general, because of the tendency of the condition to progress rapidly toward death, surgical treatment should be applied as soon as possible. If the indication for operation is congestive heart failure caused by severe aortic insufficiency, it is not essential to insist on delineating the type of dissection since the operative approach and the technique utilized are not dependent upon precise determination of the extent of the process. The exception is when involvement of certain vital arteries, such as both renal vessels, poses a more acute problem such as anuria. In the patients reported here the immediate life-threatening problem was intractable congestive heart failure secondary to aortic valve incompetence. The method of repair described is particularly applicable in the early stage of dissection, when there is minimal anatomical disruption and distortion of the aorta at the site of the intimal tear. The procedure is designed to restore mural integrity, permitting normal blood flow into the true lumen; by obliterating the false lumen, it prevents further progression of the dissection process. Annular dilatation, which plays a significant role in producing aortic insufficiency in chronic cases of ascending aortic aneurysm [3, 81, was not seen in any of the patients described here. It is encouraging to note that localized operation in the aortic root in patients with dissection extending into the iliac arteries is effective in stabilizing the lesion. Figure 4 shows an aortogram taken one year postoperatively in a patient in whom type I dissection extending into the left iliac artery was treated by insertion of a tube graft to replace the ascending aorta. In this and another patient with iliac occlusion, repair of the ascending aorta resulted in reappearance of pulses in the affected extremity. FIG. 4. Aortogram one year postoperatively showing a competent aortic valve in a patient subjected to ascending aortic replacement for type Z dissection. Distal dissection, a part of which is seen in the innominate artery, has remained stable.

7 NAJAFI ET AL. The discouraging feature in this group has been the obscure pathogenesis of the lesion. Aortic specimens from several of these patients have failed to identify the abnormal morphology responsible for the disruption of the aorta. None of the patients had any of the stigmas of Marfan s syndrome. Antihypertensive therapy as recommended by Wheat and his associates [151 was utilized in 3 hypertensive patients preoperatively. After operation, only 1 of these 3 patients became hypertensive and required similar treatment. This patient, a known hypertensive, continues to have diastolic hypertension of undetermined etiology. An important aspect of the operation relates to the site of arterial cannulation. In patients with type I dissection and a second tear distally (reentry), there is a hazard of retrograde perfusion of the dissected lumen. Undoubtedly this has contributed to the deaths of some patients treated surgically [Ill. Fortunately, in the patients described here and in many reported by others, retrograde perfusion through a cannula in the femoral artery was not hazardous. This, of course, in part relates to the absence of a second intimal tear distally. In patients with type I dissection and unilateral iliac occlusion, one can be reasonably sure that a second tear does not exist and therefore the contralateral femoral artery can be cannulated for arterial return. Liotta and his co-workers [7] advocate cannulation of the aortic arch under these circumstances. We have not tested the effectiveness of this method and hesitate to believe that it would be superior to femoral artery cannulation. Although small, this series further emphasizes the feasibility of early surgical treatment in patients with type I or I1 aortic dissection causing aortic insufficiency and particularly demonstrates the effectiveness of the procedure utilized in restoring aortic valve competence without valve replacement. References 1. Aronstam, E. M., Gomez, A. C., O Connell, T. J., Jr., and Geiger, J. P. Recent surgical and pharmacological experience with acute dissecting and traumatic aneurysms. J. Thorac. Cardiovasc. Surg. 59:231, Austen, W. G., Buckley, M. J., McFarland, J., DeSanctis, R. W., and Sanders, C. A. Therapy for dissecting aneurysms. Arch. Surg. 95:835, Cooley, D. A., Bloodwell, R. D., Hallman, G. L., and Jacoby, J. A. Aneurysms of the ascending aorta complicated by aortic valve incompetence: Surgical treatment. J. Cardiovasc. Surg. (Torino) 8: 1, DeBakey, M. E., Henly, W. S., Cooley, D. A., Morris, G. C., Crawford, E. S., and Beall, A. C., Jr. Surgical management of dissecting aneurysms of the aorta. J. Thorac. Cardiovasc. Surg. 39: 130, Hirst, A. E., John, V. J., and Kime, S. W. Dissecting aneurysms of the aorta: A review of 505 cases. Medicine (Baltimore) 37:217, Hufnagel, C. A., and Conrad, P. W. Dissecting aneurysms of the ascending aorta: Direct approach to repair. Surgery 51:84, Liotta, D., Hallman, G. L., Milam, J. D., and Cooley, D. A. Surgical treat- 480 THE ANNALS OF THORACIC SURGERY

8 Aortic Regurgitation from Dissection ment of acute dissecting aneurysm of the ascending aorta. Ann. Thorac. Stlrg. 12:582, Najafi, H. Aortic insufficiency: Clinical manifestations and surgical treatment. Am. Heart J. 82:120, Najafi, H. Aortic root aneurysm: Diagnosis and treatment. J.A.M.A. 197: 173, Najafi, H., Dye, W. S., Javid, H., Hunter, J. A., and Julian, 0. C. Emergency open heart surgery for acquired heart disease. Dis. Chest 55:456, Pappas, G., and Starzl, T. E. Retrograde false channel perfusion. Ann. Thorac. Surg. 9:263, Rohman, M., Goetz, R. H., and State, D. Surgical treatment of dissecting aneurysms of the aorta with cardiac tamponade. J. Thorac. Cardiovasc. Surg. 46:498, Spencer, F. C., and Blake, H. U. A report of the successful surgical treatment of aortic regurgitation for a dissecting aortic aneurysm in a patient with Marfan's syndrome. J. Thorac. Cardiovasc. Surg. 44:238, Wheat, M. W., Jr., and Palmer, R. F. Dissecting aneurysms of the aorta. Curr. Probl. Surg., July, Wheat, M. W., Jr., Palmer, R. F., Bartley, T. D., and Seelman, R. C. Treatment of dissecting aneurysms of the aorta without surgery. J. Thorac. Cardiovasc. Surg. 49:364, Discussion DR. JOHN J. COLLINS (Boston, Mass.): It is a particular pleasure to discuss this paper since I completely agree with Dr. Najafi. He has emphasized again that it is difficult to improve on the normal aortic valve apparatus and that it is unnecessary to sacrifice the valve merely because there is dehiscence of the intima from the adventitia. In many ascending aortic dissections the intima itself is of relatively normal caliber despite extreme distention of the adventitia. When the adventitial incision demonstrates this to be the case, it usually should be possible to reconstruct the incompetent aortic valve. We have found that it is advantageous to use a buttress of Teflon cloth, which is inserted into the void between the intima and adventitia with a keyhole cut out for the right coronary artery. This serves to anchor the aortic valve apparatus, prevent stress on the running suture line distally, and hold the aortic valve in a competent position much as a homograft is affixed. The cloth has a second very important function, and that is the prevention of late dilatation of the aortic ring, since anterolateral distention of the aortic annulus area is thereby impeded. We then oversew the base of the transected aorta in the usual fashion and reconstruct the aortic arch if that should be necessary. Our experience with this operation in 3 patients has been very successful. The longest follow-up is only eighteen months, but none of these patients has any clinical evidence of aortic insufficiency. DR. WILLIAM A. Cox (Fort Sam Houston, Tex.): In the past three years at Brooke General Hospital in Fort Sam Houston, Texas, we have operated upon 5 patients for ascending aortic aneurysm with dissection, massive aortic insufficiency, and refractory heart failure. Three of the dissections were acute, and 2 were chronic with aortic ectasia without the stigmas of Marfan's syndrome. The proximal end of the transected aorta is buttressed with a Teflon felt band placed outside the aortic root with two scallops to fit around the coronary arteries. Three of the patients had repair without valve replacement by resuspension of the cusps, but 2 required valve replacement due to dilatation of the root even though it was cinched up maximally. VOL. 14, NO. 5, NOVEMBER,

9 NAJAFI ET AL. One patient died from hemorrhage from the proximal suture line. Another died with low cardiac output due to catecholamine cardiomyopathy. The remaining 3 patients are doing well three years, two years, and one year postoperatively, respectively. DR. NAJAFI: The matter of resecting a segment of the coronary sinus of Valsalva was not really a problem in these patients. I would like to emphasize that these patients were operated upon within several days from the onset of their problem. If one operates during the early stage of the disease, the anatomical disruption is minimal. We did not find aneurysm in the sinuses of Valsalva in any of these patients. There was no intrinsic disease of the cusp. There was no dilatation of the valve annulus. The tissues looked terribly friable, but nevertheless they were good enough to allow us to perform a primary repair or graft replacement. I particularly enjoyed seeing the ingenious technical modification by Dr. Collins, and I am sure that it will be found necessary to use it in some of these patients who have extremely poor tissues, particularly proximally, for either primary anastomosis or graft replacement. Another point I would like to emphasize is hypertension. Many of these patients are severely hypertensive in addition to being in congestive heart failure. These patients should be vigorously treated even though an operation is going to be done to restore aortic valve competence. One of the hypertensive patients had a systolic pressure in excess of 300 and a diastolic pressure in excess of 200 mm. Hg postoperatively. We treated him immediately. It took several hours to bring the pressure down, but in spite of the hypertension his repair held and he has been a long-term successful patient. 482 THE ANNALS OF THORACIC SURGERY