Combined cardiac and abdominal aortic aneurysm operations

Combined cardiac and abdominal aortic aneurysm operations

Combined cardiac and abdominal aortic aneurysm operations The dual operation on cardiopulmonary bypass Eight patients underwent both cardiac operation...

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Combined cardiac and abdominal aortic aneurysm operations The dual operation on cardiopulmonary bypass Eight patients underwent both cardiac operation and repair of abdominal aortic aneurysm. All had respiratory impairment and significant impairment of left ventricular function, whereas six patients had severe diffuse distal coronary disease. In aD patients the cardiac procedure was performed first, and the patients continued to receive cardiopulmonary bypass. Rewarming was not commenced until the abdominal repair was weD under way, to protect the vital organs. There were no problems in weaning the patients from bypass, and six of the patients were extubated within 24 hours; one required ventilation for 36 hours. One patient died of colonic infarction complicated by kidney failure without being extubated. Another patient who was initially extubated in 11 hours required reintubation because of poor lung function and eventually died of multisystem organ failure caused by bilateral lower limb ischemia that persisted despite embolectomies. All survivors are weD and in New York Heart Association functional class I or II between 3 and 18 months postoperatively. We conclude that for patients considered unfit for abdominal aortic aneurysm operations because of the nature of the cardiac disease, the combined operation with cardiopulmonary bypass is both safe and effective. (J THoRAc CARDIoVASe SURG 1992;104:990-5)

S. Westaby, FRCS, A. Parry, FRCS, C. R. Grebenik, FFARCS, R. Pillai, FRCS, and P. Lamont, FRCS, Oxford, England

Cardiac complications constitute the principal cause of morbidity and mortality after abdominal aortic aneurysm repair."! In the presence of significant coronary artery disease the increased afterload during infrarenal aortic crossclamping may produce myocardial ischemia and left ventricular failure. 4• 5 Cardiovascular assessment is consequently an important part of the work-up before elective aortic aneurysm repair. Previously, in a few patients where rupture of an abdominal aortic aneurysm was considered imminent, coronary artery bypass followed by abdominal aortic aneurysm resection was undertaken during the same period of anesthesia, 6-8 but the aneurysm resection was performed after cardiopulmonary bypass was discontinued. This approach assumes that the cardiac operation has eliminated potential cardiac morbidity, From the Oxford Heart Centre, Oxford, England. Received for publication May 10, 1991. Accepted for publication Jan. 3, 1992. Address for reprints: S. Westaby, FRCS, Oxford Heart Centre, John Radcliffe Hospital, Headington, Oxford, OX3 9DU England.

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but this may not be the case. In the presence of severe diffuse coronary disease and impaired left ventricular function the risk of aortic crossclamping persists in the short term after revascularization. Even after complete myocardial revascularization, a recovery period is necessary to overcome the effects of cold cardioplegic arrest. 9, to Similarly, after surgery for critical aortic stenosis, the left ventricular ejection fraction may remain impaired for an indefinite period. II In patients with left ventricular failure a cardiac operation, either immediately or weeks before abdominal aneurysm resection, cannot guarantee safety from intraoperative events. Our policy for the patient with normal or well-preserved left ventricular function with an abdominal aortic aneurysm is to perform the cardiac procedure first followed by an abdominal aortic aneurysm operation 6 weeks to 3 months later. However, for patients with severe diffuse coronary disease and irreversible left ventricular dysfunction in whom revascularization could not be regarded as complete or patients with long-standing valvular heart disease where a cardiac operation cannot be regarded as immediately corrective, we elected to per-

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Table I. Preoperative patient assessment data Lv function Patient No.

Age (yr) 77

2

67

3

67

4

66

5

60

6

70

7

78

8

70

Cardiac lesion

Severe3-vesse1 disease unstable angina 2-vessel disease previous infarcts Chronicaortic regurgitation and circumflex coronary occlusion Severe3-vessel disease, previous infarcts Severe3-vessel disease, previous infarcts Ascending aortic aneurysm, chronic dissection Severe3-vessel disease, previous infarcts Severe3-vessel disease, previous infarcts, in atrial fibrillation

EF(%)

LVED (mmHg)

45

10

30

10

50

16

40

16

33

12

60 60

SevereLV hypertrophy 10

35

14

Respiratory status

COPD, NYHA III COPD, NYHA II COPD, NYHA III COPD, NYHA III COPD, NYHA II COPD, NYHAIV COPD, NYHA III COPD, NYHA III

COPD, Chronic obstructive pulmonary disease; EF, ejection fraction; FVC, forced vital capacity; LV, left ventricular; LVEDP, left ventricular end diastolic pressure; NYHA, New York Heart Association functional class.

form both procedures with the patient receiving cardiopulmonary bypass. The heart does not then have to eject and perform work against the crossclamped aorta. Associated impairment of respiratory function reinforces our decision to perform the combined operation rather than detracts from it because the risks of two major procedures on patients with only limited respiratory reserve. In this article we describe eight consecutive high-risk cardiac patients in whom cardiac repair and an abdominal aortic aneurysm operation were undertaken simultaneously as a combined procedure.

Patients and methods Eight male patients aged between 60 and 78 years (mean 69 years) underwent a cardiac operation and abdominal aortic aneurysm repair in combination. All were previously deemed unfit for elective repair of a rapidly expanding or painful abdominal aortic aneurysm on the grounds of severe symptomatic coronary artery disease and respiratory impairment. The preoperative conditions of the patients are summarized in Table 1. Six had severe diffuse coronary disease with previous myocardial infarction and impairment of left ventricular function. All had significant abnormalities of ventricular wall motion. In these patients the distribution of the atheroma, particularly in the distal vessels, prevented confidence that the revascularization was adequate to allow normalization of left ventricular function and safe crossclamping of the abdominal aorta in the future. One had long-standing critical aortic stenosis with a dilated left ventricle and left ventricular failure. One patient had a large chronic ascending aortic dissection with aortic regurgitation and impaired left ventricular function. This patient also

had a forced expiratory volume in I second (FEY I) of 0.9 Land severe peripheral arterial disease. Poor respiratory function was a positive factor influencing patient selection for a combined procedure as impairment of respiratory function is a significant risk factor in major surgery and even more so if two major procedures are required. All our patients were previously heavy smokers with chronic obstructive airway disease of varying degrees. Patients 1,3,4,7, and 8 were not submitted to formal lung function tests because their need for surgery was established and their respiratory status was not sufficiently poor to exclude them from surgery altogether. As an example, patient 6 had an FEY I of 0.9 L while receiving steroids and nebulizers but was still considered for the dual procedure as his only chance for a satisfactory outcome. The anesthetized patients were placed supine on the operating table and prepared from the neck to the groin. For those patients whose preoperative arteriogram showed aortoiliac disease, both thighs were prepared and the patient draped to allow aortobifemoral grafts. Median sternotomy was then performed and cardiopulmonary bypass established with an ascending aortic arterial cannula and a two-stage venous cannula in the right atrium. Cardiopulmonary bypass was established with a flow of 2.2 L/m 2/min and moderate hypothermia (28° to 32° C). The perfusion pressure was maintained at 50 to 70 mm Hg pharmacologically. After aortic crossclamping, the heart was arrested with I L cold St. Thomas' Hospital solution. For coronary artery bypass the distal anastomoses were performed first, The aortic crossclamp was then released and the heart reperfused. The proximal anastomoses were performed with a partially occlusive aortic side clamp, during which the heart spontaneously reverted to sinus rhythm or was defibrillated. The mean crossclamp time and duration of cardiopulmonary bypass was 38 minutes (range 21 to 58 minutes) and 122 minutes (range 104 to 148 minutes), respectively (Table II).

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Table II. Summary of operative and postoperative course Patient No.

Cardiac operation

Thoracic crosse/amp time (min)

Total bypass time (min)

Extubation time (min)

I 2 3 4 5 6

CABG x4 CABGx 2 AVRCABGx I CABG X 3 CABG X 3 Repair

46 21 47 29 44 58 (TCA 18)

144 105 104 132 107 148

7 8

CABGx 2 CABGX 3

24 41

114 120

36 23 15 15 10 II (reintubated at 56 hr) Not extubated 6

Outcome Alive and well at 18 me Alive and well at 10 me Alive and well at 9 me Alive and well at 7 me Alive and well at 5 mo Died 21 days postoperatively Died 9 days postoperatively Alive and well at 3 mo

AYR, Aortic valve replacement; CABG, coronary artery bypass grafts; Repair, repair of ascending aortic aneurysm. TCA, Total circulatory arrest.

One patient underwent aortic valvereplacement with a Carpentier-Edwards porcine xenograft to avoid long-term anticoagulation in view of possible surgery for peripheral vascular disease. The patient with chronic type A aortic dissection underwent excision of the aneurysm and repair of the aortic valve. The ascending aorta was replaced with a collagenimpregnated wovenDacron graft (Haemashield, Meadox Medicals, Inc., Oakland, N.J.). In this patient the arterial cannula was inserted distal to the innominate artery and the systemic temperature was reduced to 28° C. On completion of the cardiac procedure attention was directed to the abdominal aortic aneurysm. The sternotomy incision was extended down to the pubic symphis. The peritoneum was incised to the left of the small-intestine mesentery, and the incision extended to divide the ligament of Treitz, thereby allowing mobilization of the duodenojejunal flexure to the midline. The aorta was exposed from the suprarenal portion at the diaphragmatic hiatus down to the iliac vessels, which were mobilizedand clamped to prevent peripheral embolization of the aneurysm during mobilization of the neck. The sternotomy facilitated exposure of the infrarenal aorta. Clamping of the infrarenal aorta during cardiopulmonary bypass did not cause acute hemodynamic changes often seen during unprotected crossclamping. Continued hypothermic perfusion provided a degree of protection to the kidneys, allowing crossclampingabove the renal vessels if necessary. With the clamps in place, a perfusion pressure of 60 to 70 mm Hg could be maintained at flow rates of 1.5 L/m 2/min. The aneurysm was opened and the mural thrombus curetted. The aortic bifurcation was assessedfrom within to determine whether a tube or bifurcated graft was necessary, and lumbar arterial backflow was controlled with mattress sutures. In seven of the eight patients a straight tube graft was employed down to the aortic bifurcation. The patient with chronic type A dissectionrequired an aortobifemoral graft. The proximal anastomosis was performed first. When half of this anastomosis was complete, full systemicrewarming from 32° to 37° C was commenced so that on completionof the distal anastomosis cardiopulmonary bypass could be discontinued. The distal clamps were removed first to allow the graft to fill and expel air. The proximal clamp was then removed. When hemostasis was secured, cardiopulmonary bypass was discontinued and heparin reversed with protamine. Wound closure began

with chest drain insertion and approximation of the sternal edges, which then facilitated abdominal closure.

Results Six patients were extubated within 24 hours (mean 13.3 hours; range 6 to 23 hours) ofleaving the operating room, whereas one required ventilation for 36 hours. Two early postoperative deaths occurred. One patient (patient 6) had severe asthma and a preoperative FEY I less than 0.9 L despite intensive treatment with steroids and physiotherapy. He was initially extubated uneventfully but had had peripheral embolization of atheromatous debris during manipulation of the abdominal aortic aneurysm; lower limb ischemia developed as a result of this. The legs remained ischemic despite embolectomy, and secondary acute kidney failure developed. Consent for bilateral amputations was refused, and he died of sepsis and multisystem organ failure. The second death occurred in patient 7. In the immediate postoperative period he hemorrhaged from the proximal anastomosis of the aneurysm repair site and required reexploration with 22 units of transfused blood. The procedure was further complicated by episodes of ventricular fibrillation. Kidney failure developed within 48 hours, and the patient therefore received hemofiltration, but he died of respiratory failure and sepsis on the postoperative day 9. Autopsy revealed extensive colonic infarction and retroperitoneal hematoma. All six hospital survivors are in New York Heart Association functional class I or II between 3 months and 18 months postoperatively.

Discussion In patients with coronary artery disease, particularly ischemic cardiomyopathy, crossclamping of the descend-

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ing thoracic or abdominal aorta causes elevation of the left atrial pressure and subendocardial ischemia. Cardiac output is maintained at the expense of increased filling pressure. Whereas aortic crossclamping causes a fall in pulmonary capillary wedge pressure for nonischemic ventricles, in coronary patients the pulmonary capillary wedge pressure frequently exceeds 14 mm Hg.4 Other studies demonstrated the rise in left ventricular wall stress and consequent subendocardial ischemia during aortic crossclamping.P'l" Pharmacologic afterload reduction with sodium nitroprusside reverses the increase in pulmonary capillary wedge pressure and decreases subendocardial ischemia. Conflicting findings have been reported after crossclamp release. These vary from normalization of the cardiac indices in one group!" to a prolonged and progressive rise in pulmonary capillary wedge pressure with normal blood pressure in another.F Patients with low ejection fractions are at greatly increased risk of refractory left ventricular failure-' and dysrhythmias'" after crossclamping. In one series of patients a cardiac mortality of 75% was recorded for patients with an ejection fraction of less than 30%.15 Coronary revascularization has been demonstrated to reduce the risk of acute cardiac events in patients with coronary artery disease undergoing separate major procedures.U'l? However, this benefit can be convincingly demonstrated only when the second procedure is performed more than 12 to 24 months after bypass grafting." For patients with coronary artery disease and abdominal aortic aneurysms, two different approaches were adopted in the past. The most common course is for myocardial revascularization to be undertaken first, followed at a later date by elective abdominal aortic aneurysm repair. This is our approach for patients who can be satisfactorily revascularized and who have reasonable left ventricular function (ejection fraction> 30%). Alternatively, some workers adopted a one-stage procedure of myocardial revascularization followed by discontinuation of cardiopulmonary bypass, then aneurysm repair at the same operation. The comparative reported mortality from immediate cardiac events for these approaches were 2.8% versus 2.4%, respectively, when the abdominal aortic operation was performed within 5 days to3 weeksof the cardiac procedure. J8 A staged procedure therefore carries no benefit from a cardiac standpoint. Particularly for elderly patients or those with severe respiratory impairment, the prospect of consecutive major surgical procedures with a prolonged intervening convalescent period is unsatisfactory. Certain subgroups exist in which the potential for a staged approach does not exist. Patients with unstable

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angina and large symptomatic abdominal aneurysms are at risk for aneurysm rupture if the staged procedure is adopted. In Smith's series-? of 38 patients the incidence of aneurysm rupture was 10.5% while patients awaited the second stage. This carried a 25% mortality rate for these patients. Because of this situation, the combined surgical approach was adopted. Ruby and co-workers?' reported six combined procedures with no operative mortality; for their patients cardiopulmonary bypass was discontinued before the abdominal incision was made and the crossclamps applied. However, for patients with severe diffuse coronary disease or with extensive myocardial damage from previous myocardial infarction, myocardial revascularization cannot be guaranteed to protect the heart against early aortic crossclamping. With the consecutive procedure the heart is still recovering from cardioplegia, and in patients with severe distal disease coronary bypass cannot be guaranteed to provide satisfactory myocardial blood flow. An acute rise in afterload during crossclamping and consequent increase in myocardial wall tension may still result in myocardial ischemia. Indeed, for patients with coronary disease and impaired left ventricular function the postoperative care revolves around maximizing myocardial perfusion by afterload reduction. To discontinue cardiopulmonary bypass and then crossclamp the abdominal aorta is illogical for these patients. Aftercooling after bypass may also be profound-i and may increase peripheral vascular resistance and stroke work. These problems can be eliminated by continuing cardiopulmonary bypass and systemic rewarming during the abdominal aortic repair. The heart does not then eject against a crossclamped aorta but continues its recovery after cold cardioplegic arrest. Also, because perfusion with systemic hypothermia affords protection to the kidneys, spinal cord, and gut, it is illogical to perform the cardiac repair, rewarm, and then disconnect the bypass from the patient before the abdominal procedure. In our series all patients described were declined abdominal aortic operations on cardiac or cardiorespiratory grounds. Those patients with poor left ventricular function were considered unfit for unprotected aortic crossc1amping, even after myocardial revascularization or aortic valve replacement. The two patients who died were considered to be at very high risk for either procedure independently and highly unlikely to survive consecutive cardiac and abdominal aortic operations. The six patients with coronary disease were regarded to be at high risk for the coronary operation alone on the grounds of severe diffuse atheroma, which precluded complete revascularization. It was therefore in the specific interests of these

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patients to undergo abdominal aortic aneurysm resection while stroke work was considerably reduced. Clinical judgment would not allow these patients to be randomly assigned to a simultaneous or staged procedure because they had all been rejected for the staged approach. In all eight patients cardiopulmonary bypass was continued until after the abdominal aortic crossclamps were removed, thus affording protection against the circulatory collapse frequently encountered on washout of metabolites from the ischemic legs. Expeditious cardiac and abdominal aortic aneurysm repair resulted in cardiopulmonary bypass times that were well within acceptable limits. All patients were easily weaned from bypass, and the outcome was successful in 75% of patients. Those who died did not have a cardiac event. Other combined coronary and vascular operations may also be performed with the patient receiving hypothermic cardiopulmonary bypass. Hypothermia provides an element of cerebral protection for patients undergoing carotid endarterectomy,23,24 although preferably the carotid operation is undertaken before coronary bypass. 25-28 Equally, patients with renal artery stenosis may benefit from systemic cooling before occlusion of the renal artery. Because the combination of abdominal aortic aneurysm and angina is common.P: 30 our method may eventually prove preferable to staged procedures even for patients in whom myocardial revascularization is uncomplicated. Detailed preoperative assessment before major vascular surgery now routinely includes an exercise test followed by coronary angiography if this proves positive. Presently we advocate our combined approach with the aneurysm repair during cardiopulmonary bypass for patients with severe diffuse coronary disease in whom the prospect of effective revascularization is remote, patients with severely impaired left ventricular function, and patients whose respiratory function is so poor that survival from consecutive major procedures is unlikely. The same principle applies for those with valvular heart disease, impaired left ventricular function, and pulmonary hypertension.

1.

2.

3.

4.

REFERENCES Hertzer N. Fatal myocardial infarction following abdominal aortic aneurysm section. Ann Surg 1980;192:667-73. Brown OW, Hollier LH, Pairolero PC, et al. Abdominal aortic aneurysm and coronary artery disease: a reassessment. Arch Surg 1981;116:1484-8. Hollier LH, Plate G, O'Brien PC, et al. Late survival after abdominal aneurysm repair: influence of coronary artery disease. J Vase Surg 1984;1:290-9. Attia RR, Murphy JD, Snider M, et al. Myocardial ische-

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mia due to infrarenal aortic cross clamping during aortic surgery in patients with severe coronary disease. Circulation 1976;53:961-5. 5. Gooding JM, Archie JP, McDowell H. Hemodynamic response to infrarenal cross clamping in patients with and without coronary artery disease. Crit Care Med 1980;8: 382-5. 6. Reis RL, Hannah H. Management of patients with severe coexistent coronary artery and peripheral vascular disease. J THoRAc CARDIOVASC SURG 1977;73:909-18. 7. Emery RW, Ott RA, Bernhard V, et al. Surgical approach to combined coronary revascularization and abdominal aortic aneurysmectomy. J Cardiovasc Surg 1988;29:143-5. 8. Ruby ST, Whitemore AD, Couch NP, et al. Coronary artery disease in patients requiring abdominal aortic aneurysm repair: selectiveuse of combined operation. Ann Surg 1985;201:758-64. 9. Mangano DT. Biventricular function after myocardial revascularization in humans: deterioration and recovery patterns during the first 24 hours. Anaesthesiology 1985; 62:571-7. 10. Braunwald E, Kloner RA. The stunned myocardium: prolonged post-ischemic ventricular dysfunction. Circulation 1982;66:1146-9. 11. Monrad ES, Hess OM, Murakani T, Nanogi H, Cerin WJ, Krayenbuehl HP. Time course of regression of left ventricular hypertrophy after aortic valve replacement. Circulation 1988;77:1345-5. 12. Spargo PM, Crosse MM. Anaesthetic problems in cross clamping of the thoracic aorta. Ann R Coli Surg Engl 1988;70:64-8. 13. Kazmers A, Cerqueira MD, Zierler RE. Perioperative and late outcome in patients with left ventricular ejection fraction of 35% or less who require major vascular surgery. J Vase Surg 1988;8:307-15. 14. Harpole DH, Clements FM, Quill T, Wolfe WG, Jones RH, McCann RL. Right and left ventricular performance during and after abdominal aortic aneurysm repair. Ann Surg 1989;209:356-62. 15. Mosley JG, Clarke JMF, Ell PJ, Marston A. Assessment of myocardial function before aortic surgery by radionuelide angiocardiography. Br J Surg 1985;72:886-7. 16. Neri R, Mestroni L, Salvi A. Arrhythmias in dilated cardiomyopathy. Postgrad Med J 1986;62:593-7. 17. McCann RL, Wolfe WG. Resection of abdominal aortic aneurysms in patients with low ejection fractions. J Vase Surg 1989;10:240-4. 18. Reul GJ Jr, Cooley DA, Duncan JM, et al. The effect of coronary bypass on the outcome of peripheral vascular operations in 1093 patients. J Vase Surg 1986;3:788-98. 19. McCollum CH, Garcia-Rinaldi R, Graham JM, DeBakey ME. Myocardial revascularization prior to subsequent major surgery in patients with coronary artery disease. Surgery 1977;81:302-4. 20. Smith RB. In discussion of Ruby et al.21 21. Ruby ST, Whittemore AD, Couch NP, Collins JJ, Cohn L,

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Shemin R, Mannick JA. Coronary artery disease in patients requiring abdominal aortic aneurysm repair: selective use of a combined operation. Ann Surg 1985;201:75864. 22. Walker WE. In discussion of Ruby et al. 2 ! 23. Blombery PA, Ferguson lA, Rosengarten DS, et al. The role of coronary artery disease in complications of abdominal aortic aneurysm surgery. Surgery 1987;101:150-5. 24. Hertzer NR, Young TR, Beven EG, et al. Late results of coronary bypass in patients with infrarenal aortic aneurysms: the Cleveland Clinic Study. Ann Surg 1987;205: 360-7. 25. Reis RL, Hannah H. Management of patients with severe co-existentcoronary artery and peripheral vascular disease. J THORAC CARDIOVASC SURG 1977;73:909-18.

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26. Schwartz RL, Garrett JR, Karp RB, et al. Simultaneous myocardial revascularization and carotid endarterectomy. Circulation 1982;66(suppl 1):97-101. 27. Bernhard VM, Johnson WD, Peterson JJ. Carotid artery stenosis: association with surgery for coronary artery disease. Arch Surg 1972;105:837-40. 28. Okies lE, MacManus Q, Starr A. Myocardial revascularization and carotid endarterectomy: a combined approach. Ann Thorac Surg 1977;23:560-3. 29. Craver JM, Murphy DA, Jones EL, et al. Concomitant carotid and coronary artery revascularization. Ann Surg 1982;195:712-9. 30. Korompai FL, Hayward RH, Knight WL. Non-cardiac operations combined with coronary artery bypass. Surg Clin North Am 1982;62:215-24.

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