Left Ventricular Wall Resection for Aneurysm and Akinesia due to Coronary Artery Disease: Fifty Consecutive Patients

Transcription

1 Left Ventricular Wall Resection for Aneurysm and Akinesia due to Coronary Artery Disease: Fifty Consecutive Patients Armand A. Lefemine, M.D., Rajagopalan Govindarajan, M.D., K. Ramaswamy, M.D., Harrison Black, M.D., Irving Madoff, M.D., and Nicholas Sanella, M.D. ABSTRACT Left ventricular wall resection with or without vein bypass grafting was performed in 50 consecutive patients with aneurysm or an akinetic segment with poor left ventricular hemodynamics. Ejection fraction averaged 29% and left ventricular end-diastolic pressure averaged 20 mm Hg. Associated valve disease was present in 4 patients (28%). Hospital mortality was 22% ( patients) and late mortality was 20% (0 patients). The lowest mortality (3%, death) was found in patients who had anterior apical resection with associated vein bypass, in whom prophylactic balloon pumping was used when needed for ejection fractions of less than 30%. A high mortality occurred with associated valve replacement (6 deaths, 86%) and posterior aneurysm. Among 39 patients followed for an average of twenty-four. months, 34 (87%) improved one class and 8 (46%) improved two classes of the New York Heart Association Functional Classification. Extensive myocardial destruction resulting from one or more myocardial infarctions may present a variety of pathological patterns that alter the risk and feasibility of a corrective operation. The location and extent of the wall dysfunction and the associated coronary artery and valve problems must be weighed in deciding the value of surgery for a particular patient. Resection of ventricular saccular aneuryms has resulted in significant salvage and hemodynamic improvement [l, 2,6]. In contrast, the large, dilated heart with an ejection fraction of less than 40% From the Divisions of Cardiothoracic Surgery and Cardiology, St Elizabeth s Hospital, and the Departments of Surgery, Tufts University School of Medicine, Harvard Medical School, and Boston University School of Medicine, Boston, MA. Accepted for publication Sept 27, 976. Address reprint requests to Dr. Lefemine, St Elizabeth s Hospital, 736 Cambridge St, Brighton, MA and extensive areas of akinesia or hypokinesia has been difficult to evaluate in terms of surgical risk and result. Actually many patients have a combination of aneurysm, akinesia, hypokinesia, and valvular insufficiency in addition to coronary artery disease. The ventriculogram is sometimes difficult to interpret because the large volume and high tension may appear as a global rather than a segmental problem. The benefits of revascularization alone in this particular group are open to question and have not been demonstrated in our experience. Our approach to patients with impaired ventricular function has been to reduce the size of the ventricle, along with any reasonable revascularization and valve replacement. This report deals with our experience in 50 consecutive patients who underwent ventricular wall resection for segmental necrosis resulting from coronary artery disease. Material and Methods Resection of a portion of the left ventricular wall was carried out in 50 patients in whom significant dysfunction was demonstrated on ventriculography. The patients ranged in age from 36 to 73 years (average, 53 years); 40 of them (80%) were male. Functional classification according to New York Heart Association criteria revealed 6 patients in Class I (2O/0), 7 patients in Class (34%), and 27 patients in Class IV (54%). Fourteen patients (28%) had associated valvular or septa defects, as detailed in Table. All but had significant coronary artery disease in the form of arteriosclerotic stenosis or occlusion. Forty (80%) of the patients had advanced disease of two or more vessels. The preoperative hemodynamic status is analyzed in Table 2. Ejection fraction, cardiac index, end-diastolic 46

2 462 The Annals of Thoracic Surgery Vol 23 No 5 May 977 Table. Associated Value Disease in 50 Patients Disorder Mitral regurgitation (-4+) 0 Aortic and mitral stenosis and insufficiency Tricuspid and mitral insufficiency VSD and mitral insufficiency Aortic stenosis and insufficiency Total 4 VSD = ventricular sep tal defect. Patients pressure, and mean pulmonary artery pressure were significantly abnormal. Table 3 shows the distribution of these hemodynamic measurements. In some patients resection was combined with saphenous vein bypass and valve replacement. One patient also had closure of an interventricular septa defect. All patients were studied preoperatively by standard catheterization and angiography techniques. Ten patients were studied postoperatively at intervals of three weeks to eight months. Ejection fractions were calculated using the length-area method from the left ventricular cineangiogram in the 30- degree right anterior oblique position [4. Cardiac output was determined by indicatordilution and Fick. techniques. The ventricular wall dysfunction was classified as an aneurysm if a definite sac with paradoxical motion was observed. When paradoxical motion (and contraction were absent, the disorder was classified as akinesia, though many of these patients had an associated small aneurysm of the apex. Patients who had large hearts with almost global akinesia and hypo- kinesia except for contraction at the base were classified as akinetic, though some of these would more properly be classified as having an aneurysm at the time of operation, since the wall was composed of thin, fibrotic scar instead of the thickened fibromuscular tissue of the akinetic segment. Surgical techniques included standard extracorporeal bypass with mild hypothermia and induced ventricular fibrillation. The central portion of the aneurysm or akinetic area was excised, leaving a scarred edge for closure reinforced with strips of Teflon felt. Palpation between fingers and observation for changes of the endocardium were helpful in locating the point of transition to normal muscle. The septum was not excised, though in 2 patients the closure sutures were placed through the septum to include the adjacent right ventricular wall. Anterior resections often extended from the base of the ventricle anteriorly to the papillary muscles posteriorly. The Avco intraaortic balloon was used prophylactically to assist circulation in patients with ejection fractions below 30% and, when indicated, for low cardiac output at the end of extracorporeal bypass. For elective placement, the decision was made in advance of the operation and carried out before or at some appropriate time during the procedure, before any output problems were demonstrated. The balloon was removed two to seven days later, after a period of weaning. Results If the patients are classified clinically as having () angina, (2) congestive heart failure, or (3) angina plus congestive heart failure, distinct differences in surgical survival are seen (Table 4). Evidence for chronic intermittent congestive Table 2. Preoperl;!tiue Hemodynamic Data in Patients Determination Patients Range Mean SD Ejection fraction ' Cardiac index End-diastolic pressure Pulmonary artery pressure

3 463 Lefemine et al: LV Wall Resection for Aneurysm and Akinesia Table 3. Distribution of Normal and Abnormal Hemodynamic Values in Patients Determination Normal Abnormal Left ventricular end-diastolic pressure (mm Hg) Pulmonary artery pressure (mm Hg) Cardiac index (L/min/m2) Ejection fraction (%) 0-3, 5 patients 0-5, 9 patients , 20 patients 60-50, 3 patients 4-20, 4 patients 5-20, 5 patients , 2 patients 50-40, 6 patients 20-30, 4 patients 20-30, 3 patients , 3 patients 40-30, 4 patients 30-40,... 7 patients 30-40, 40-50, 9 patients 4 patients -4.5, <I, 4 patients patient 30-20, 20-9, 4 patients 0 patients Table 4. Correlation of Operative Mortality and Symptoms in 50 Patients Symptom ~~ Angina CHF Angina + CHF Total Patients Survivors O/O Survival CHF = congestive heart failure. heart failure was present in 33 (66%) of the patients. The location and nature of the myocardial necrosis had a distinct effect on surgical survival, although the number of patients with large posterior lesions and acute myocardial infarction was not large enough for statistical evaluation (Table 5). The operations varied in technical complexity from simple resection of an aneurysm to combined resection, coronary bypasses, valve replacement, and closure of a ventricular septa defect (Table 6). Anterior apical resection plus single or multiple bypasses, performed in 3 patients, was associated with a low mortality ( death, 3.2%). Valve replacement in addition to resection and bypass in 7 patients resulted in 6 deaths, a mortality of 86%. This figure includes two unusual causes of death: an air embolus and a retrograde coronary embolus from an abdominal aortic aneurysm. A large posterior wall aneurysm resulted in 2 operative deaths. Balloon counterpulsation was an invaluable aid for circulatory support. It was used in two ways: () to help the patient with postoperative shock or low cardiac output and (2) on a prophylactic basis in anticipation of temporary low cardiac output problems. Of interest is the fact that the intraaortic balloon was used in 24 of the 36 patients (72%) for whom it was available. Among the 4 patients having prophylactic balloon support, 3 survived. Four of the 0 patients who had balloon support for low cardiac output after bypass lived. The 4 operative deaths resulted from myocardial failure. One of these was due to a global infarction present before operation, and another to an unsuspected coronary embolus from an aortic aneurysm (Table 7). Postoperative deaths occurred within seven days; all resulted from myocardial failure and cardiogenic shock with exception, the patient who died from air embolus. Follow-up ranged from two months to five years (average, twenty-four months). There were 0 late deaths (20%), all related to heart disease. Nine patients died from cardiac failure

4 464 The Annals of Thlxacic Surgery Vol 23 No 5 May 977 Table 5. Operative A4ortality in 50 Patients Myocardial Abnormality Patients Survivors O/O Survival Chronic anterior aneiirysm 4 Chronic anterior-apical akinesia 29 Chronic posterior aneurysm + akinesia 2 Acute infarction with shock 3 Acute infarction with angina 2 Total Table 6. Operative Mortality by Operation Performed in 50 Patients Operation Patients Survivors O/O Survival Resection only (2 acute infarctions) Anterior resection i- bypass Anterior resection i- 2 bypasses Anterior resection i- 3 bypasses Posterior resection.t 2 bypasses Resection + valve replacement with or without bypass Total Table 7. Causes of Death among 50 Patients Operation Intraoperative deaths Posterior aneurysm + 2 bypasses Posterior aneurysm + 2 bypasses + VSD + MVR Anterior resection MVR bypass Anterior resection + MVR + 3 bypasses Postoperative deaths Anterior resection + MVR + 2 bypasses Anterior resection 2 bypasses Anterior resection + AVR Anterior resection MVR + AVR + bypass Anterior resecticn + bypass Anterior resection of acute infarction Anterior resection Cause of Death Myocardial failure Coronary embolus, myocardial failure Myocardial failure Preoperative global infarction Air embolus Myocardial infarction Myocardial failure Cardiogenic shock Myocardial infarction, arrhythmia Cardiogenic shock, myocardial infarction Cardiogenic shock MVR = Mitral valve replacement; AVR = aortic valve replacement.

5 465 Lefemine et al: LV Wall Resection for Aneurysm and Akinesia Table 8. Functional lmprovement (NYHA Class) in 39 Survivors following Left Ventricular Wall Resection Improvement Patients 0% Improved class Improved 2 classes 8 46 Improved 3 classes 6 5 and associated arrhythmias. One patient died during a second operation three years later for progression of disease. Thus, in five years 2 (42%) of the original group had died. Improvement in 39 survivors was judged according to the New York Heart Association Functional Classification (Table 8). Significant symptomatic improvement occurred in 34 (87%) of the survivors. Postoperative hemodynamic assessment in 0 patients is presented in the Figure. Comment Patients with significant ventricular wall dysfunction have a complex mixture of pathological Postoperative hernodynamicstudies in 0 patients. Ejection fraction and end-systolic volumes revealed consistent improvement that correlated well with clinical changes. (SVI = stroke volume index; EDV = end-diastolic volume; ESV = end-systolic volume; EF = ejection fraction; LVEDP = left ventricular end-diastolic pressure; CI = cardiac index.) and surgical conditions that vary in their accessibility and suitability for repair. The classification of a lesion as an aneurysm or an akinetic segment is arbitrary and is based on the presence or absence of a saclike lesion with paradoxing motions and with distinct margins. Our experience indicates that an aneurysm is composed of thin fibrous tissue, and an akinetic segment has a thicker wall composed of variably scarred muscle that does not contract. At times the differentiation by ventriculography is impossible. There is no difference in surgical results, and therefore indications for operation should be based on the limits imposed by the hemodynamic variables and the associated coronary, valvular, and septa problems. In patients who have large, dilated hearts with distinct aneurysms, it may be difficult or even impossible to differentiate segmental versus global problems of contraction because the wall tension, as dictated by the law of Laplace (T = R X P), may be extremely high. Criteria for inoperability cannot be defined from this study because many of the patients who had very poor ventricular function as defined by hemodynamic measurements and ventriculography did well if the problem was localized anteriorly and apically, and if resection was combined with vein bypasses. Electrocardiographic localization of previous and current infarcts was often helpful in localizing the scarred segment. Echocardiography will undoubtedly offer additional infor- s V I EDV ESV EF L VEDP GI

6 466 The Annals of Thoracic Surgery Vol 23 No 5 May 977 mation on the contractility and motion of parts of the left ventricle. High risk existed when the whole posterior wall was replaced by scar or when mitral or aortic valve disease was present in addition to the wall dysfunction and coronary disease. Our experience with extensive posterior wall destruction is limited to 2 patients, and both were treated before balloon counterpulsation was available. However, myocardial loss was so extensive that it probably precluded improvement of funtztion. Significant mitral valve insufficiency is usually present in these cases. It is not fully apparent why there is a high risk associated with valve replacement in addition to wall resection and coronary bypass. The only patient who survived the combined procedure underwent ventricular wall resection and replacement of the tricuspid valve. Patients who underwent mitral and aortic valve replacement in addition to resection and bypass did not survive the operation, although 2 of them died because of air and coronary emboli. Other patients with associated mitral valve incompetence (0-2+) who were not subjected to valve replacement did survive but had limited exercise tolerance and in s,ome cases remained in congestive failure. The intraaortic balloon has played an important role in the support and salvage of this group of patients. We believe it is an important adjunct for preventing low-output states and for avoiding the use of potent inotropic and vasoconstrictive agents in the first 48 postoperative hours. Our confidence in the usefulness of circulatory support in this group of patients is shown by the use of the intraaortic balloon in 36 patients, although it was used prophylactically in the majority. The circulatory support may also maintain vein graft patency by increasing flow rates. Justification for performing surgery in this group of patients must be based on the natural history of the disease and upon the improvement noted in the survivors. Schlichter and coworkers [8] studied 02 patients with aneurysm and found that 73% died within three years and 88 O/o within five years, usually from congestive failure, recurrent myocardial infarctions, or systemic embolization. Pells and D Alonzo [7 found that the five-year survival was 24% in patients with postinfarction aneurysm versus 74% for patients surviving an acute myocardial infarction. The hemodynamic sequelae of adynamic segments are similar to those of aneurysms if enough ventricular wall is inactivated by a pathological process [3,5. It is fortunate that most ventricular aneurysms and adynamic segments occur anteriorly and apically as a result of disease of the left anterior descending coronary artery [7 since these locations are associated with the best results and lowest mortality when combined with bypass. Present evidence indicates that survivors are hemodynamically and functionally improved over their medically treated counterparts, though comparable survival rates at the threeand five-year level are not available yet. References. Cooperman M, Stinson EB, Griepp RB, et al: Survival and function after left ventricular aneurysmectomy. J Thorac Cardiovasc Surg 69:32, Favaloro RG, Effler DB, Groves LK, et al: Ventricular aneurysm: clinical experience. Ann Thorac Surg 6:277, Gorlin R, Klein MS, Sullivan MD: Prospective correlative study of ventricular aneurysm. Am J Med 42:52, Kasser IS, Kennedy JW: Measurement of left ventricular volume in man by single plane cineangiography. J Invest Radio 4233, Klein MD, Herman MV, Gorlin R: A hemodynamic study of left ventricular aneurysm. Circulation 35:64, Loop FD: Ventricular aneurysmectomy. Surg Clin North Am 5:07, Pells S, D Alonzo CA: Immediate mortality and five year survival of employed men with a first myocardial infarction. N Engl J Med 270:95, Schlichter J, Hellerstein HK, Katz LN: Aneurysm of the heart: correlative study of 02 proved cases. Medicine 33:43, 954