Open-Heart Surgery in Patients More than 65 Years Old

Transcription

1 Open-Heart Surgery in Patients More than 65 Years Old Donald A. Barnhorst, M.D., Emilio R. Giuliani, M.D., James R. Pluth, M.D., Gordon K. Danielson, M.D., Robert B. Wallace, M.D., and Dwight C. McGoon, M.D. ABSTRACT At the Mayo Clinic from 1968 to 1973, 305 open-heart operations were performed on patients more than 65 years old. The overall operative mortality rate was 15.7%. Of the various types of operations, aortic valve replacement was associated with a mortality of 10.6%; mitral valve replacement, 20.0%; multiple valve replacements, 42.4%; coronary artery grafting, 3.7%; coronary grafting plus valve replacement, 23.1%; and miscellaneous procedures, 8.3%. Advanced disease, inability to achieve good coronary perfusion during operation, intraoperative ventricular fibrillation, postoperative myocardial infarction, and low cardiac output were factors in mortality. Open-heart operations can be done in patients more than 65 years old with an acceptable operative mortality. A s results have progessively improved in open-heart surgery, the indications for operation have been extended further toward the extremes of age. Various authors [ 1-3, 8-10] have documented that cardiac procedures can be performed on older patients with an operative risk not too disparate from that of the general population. Likewise, satisfactory results can be obtained for sufficiently long periods to warrant these risks [l-3, 8, 91. We have attempted to identify the operative mortality for the commonly performed open-heart procedures in patients who are older than 65 years of age [5]. For this group, we have reviewed in addition multiple preoperative, operative, and postoperative factors in survivors and nonsurvivors in an attempt to identify remediable causes of death. Clinical Material and Methods A total of 305 open-heart operations were performed on 300 patients who were 66 years of age or older during the 5-year period from September, 1968, to August, One hundred eighty-five operations were done on men and 120 on women. Eighteen were done on patients in New York Heart Association Functional Class 11, 228 in Class 111 patients, and 59 on patients who were in Class IV at the time of operation. Some of the Class 111 patients From the Mayo Clinic and Mayo Foundation, Rochester, Minn. Presented at the Tenth Anniversary Meeting of The Society of Thoracic Suzgeons, Los Angeles, Calif., Jan , Address reprint requests to Dr. Barnhorst, Mayo Clinic, Rochester, Minn VOL. 18, NO. 1, JULY,

2 BARNHORST ET AL. had been in Class IV prior to operation but their conditions had improved with medical therapy. Of the 305 procedures, 214 involved patients who were between 66 and 70 years old, 74 were done on patients between 71 and 75 years, and 17 on patients between 76 and 80 years. Bypass techniques were reasonably uniform. A bubble oxygenator with mild hypothermia was used in all patients. For patients in whom the aortic root was opened, coronary perfusion was induced whenever possible. Mitral valve replacements were done either with the aorta cross-clamped or with induced electric fibrillation. Results Operative mortality varied considerably among the patients undergoing the various procedures (Table 1). Forty-eight patients died within the first postoperative month or while still in the hospital, for an overall operative mortality rate of 15.7a/,. Operative mortality was low for patients who underwent coronary artery bypass grafting. The only death was that of a 67- year-old woman who was discharged from the hospital after an uneventful postoperative course. She returned 1 week later with deep venous thrombophlebitis and died 2 days later from a massive embolus occluding both carotid arteries. The origin of the embolus was not determined at postmortem examination. Mortality for aortic valve replacement was similarly reasonable, although it was approximately twice that in our overall series of aortic valve replacement [6, 71. The mortality rate of ZOyo for isolated mitral valve replacement also was twice as high as in our earlier 10-year review of patients of all ages [12]. The category of multiple valve replacements includes all operative procedures involving the surgical correction of more than one valve. These patients had at least one valve replaced with a prosthesis, but some had a second or third valve abnormality treated with commissurotomy or valvuloplasty rather than valve replacement. Two patients who survived and 2 who died had undergone triple-valve replacement. The entire group of TABLE 1. RESULTS OF OPEN-HEART OPERATIONS IN PATIENTS MORE THAN 65 YEARS OLD-SEPTEMBER, 1968, TO AUGUST, 1973 No. of No. of Mortality Procedure Operations Deaths (%) Aortic valve replacement Mitral valve replacement Multiple valve replacements Coronary artery bypass grafting Coronary artery bypass grafting plus valve replacement Miscellaneous Total THE ANNALS OF THORACIC SURGERY

3 Open-Heart Surgeiy in Older Patients TABLE 2. CAUSES OF DEATH AFTER OPEN-HEART OPERATIONS IN 48 PATIENTS MORE THAN 65 YEARS OLD- SEPTEMBER, 1968, TO AUGUST, 1973 Cause of Death Myocardial infarction Low cardiac output syndrome Sepsis Ventricular arrhythmia Cerebrovascular accident Technical error Hemorrhage Pulmonary insufficiency Renal failure Hepatic failure Total No. of Patients patients with multiple valve problems had the highest mortality rate (42.4%)- The combination of valve replacement with coronary artery bypass grafting resulted in an overall mortality of 23.1 yo, with 2 deaths occurring among 9 patients who had aortic valve replacement and 1 death among 4 patients who had mitral valve replacement. In the miscellaneous group of operative procedures, 3 of the 12 patients underwent closure of an atrial septal defect; none of these patients died. The 1 death in the miscellaneous group resulted from persistently low cardiac output in a patient who had cardiac arrest in the operating room and who, after resuscitation, underwent ventricular septal myotomy and mitral valvuloplasty for idiopathic hypertrophic subaortic stenosis. Myocardial infarction and low cardiac output syndromes were the main causes of death among the 48 patients who died (Table 2). Sepsis accounted for 8 deaths, but several patients had sepsis as the last insult in an already difficult postoperative course. For each type of procedure, survivors and nonsurvivors were compared with respect to various factors. In patients who underwent aortic valve replacement, more deaths occurred in those who were in Functional Class IV (p < 0.05), in those who had had a significant period of hypotension prior to the induction of bypass (p > 0.05), and in those who had less than ideal coronary artery perfusion during bypass (p < 0.05) (Tables 3-5). Coronary perfusion was considered good if both right and left coronary arteries were perfused throughout most of the procedure at flows of at least 100 ml. per minute for the left coronary artery and at least 50 ml. per minute for the right coronary artery. Perfusion was also considered good if the right coronary artery was too small to cannulate but left coronary flow was good and the heart remained beating. Fair or poor coronary perfusion was defined as the inability to perfuse either of the coronary arteries or the ability to perfuse only the right coronary artery or both arteries only sporadically. VOI.. 18, NO. 1, JULY,

4 BARNHOKST ET AL. TABLE 3. PREOPERATIVE VARIABLES IN 143 SURVIVORS AND 17 NONSURVIVORS OF OPEN-HEART' OPERATIONS FOR AORTIC VALVE REPLACEMENT IN PATIENTS MORE THAN 65 YEARS OLD-SEPTEMBER, 1968, TO AUGUST, 1973 Survivors Nonsurvivors Variable (73 (%) Functional Class IV Congestive heart failure Atrial fibrillation Normal sinus rhythm Associated coronary disease Coronary angiography performed Primarily aortic stenosis Primarily aortic insufficiency Previous myocardial infarction The incidence of most postoperative complications was significantly higher among nonsurvivors than survivors, especially low cardiac output (p < 0.01) and myocardial infarction (p < 0.01). Coronary artery disease did not seem to significantly affect early survival after aortic valve replacement. Associated coronary artery disease was deemed present if the patient had documented angiographic evidence or electrocardiographic changes characteristic of previous myocardial infarction or if the operating surgeon found severe coronary disease at operation. By these criteria, the degree of involvement could not be compared accurately between survivors and nonsurvivors. Mean bypass time was longer in nonsurvivors, but this was largely due to prolonged bypass support in patients who did poorly after the first attempt to discontinue perfusion. Of patients undergoing mitral valve replacement, more nonsurvivors than survivors were in Functional Class IV (p < 0.05), had primarily mitral regurgitation (p > 0.05), had evidence of previous myocardial infarction (p < 0.01), and were in ventricular fibrillation during bypass (Tables 6-8). More nonsurvivors than survivors had postoperative complications. Especially lethal was acute myocardial infarction. No patient with primarily mitral TABLE 4. OPERATIVE VARIABLES IN 143 SURVIVORS AND 17 NONSURVIVORS OF OPEN-HEART OPERATIONS FOR AORTIC VALVE REPLACEMENT IN PATIENTS MORE THAN 65 YEARS OLD-SEPTEMBER, 1968, TO AUGUST, 1973 Variable Survivors Nonsurvivors Mean operating time 4.0 hr. 4.6 hr. Hypotension before bypass 5.6% 17.6y0 Mean bypass time 1.4 hr. 2.3 hr. Bypass rhythm Beating 55.9y0 47.1% Ventricular fibrillation 44.1 % 52.9y0 Coronary perfusion Good 90.1 yo 70.6% Fair to none 9.9% 29.4y0 84 THE ANNALS OF THORACIC SURGERY

5 Open-Heart Surgery in Older Patients TABLE 5. POSTOPERATIVE COMPLICATIONS IN 143 SURVIVORS AND 15 NONSURVIVORS OF OPEN-HEART OPERATIONS FOR AORTIC VALVE REPLACEMENT IN PATIENTS MORE THAN 65 YEARS OLD- SEPTEMBER, 1968, TO AUGUST, 1973 Complication D ysrhy thmia Low cardiac output Myocardial infarction Cerebrovascular Renal Pulmonary Sepsis Survivors Nonsurvivors (%) (%) stenosis died, indicating the better prognosis for patients with this lesion. The incidence of associated coronary artery disease, using the same criteria as for patients with aortic valve replacement, was the same in both survivors and those who died during or after mitral valve replacement. Similar variables were considered in the patients undergoing other procedures. In the group having multiple valve replacement, ventricular fibrillation during bypass was associated with a significantly higher mortality (p < 0.05) and postoperative complications were more numerous in nonsurvivors than in survivors. Low cardiac output was a particular problem, occurring in 26.30/, of survivors and in 92.3a/, of nonsurvivors. Comment The operative mortality was 10.6oj, for patients older than 65 years of age who underwent aortic valve replacement. A significant percentage of these patients had far-advanced disease, and this was a definite factor contributing to their deaths. Adequacy of intraoperative coronary perfusion in this age group also seemed to be a factor in operative survival. Mitral valve replacement was associated with twice the mortality rate TABLE 6. PREOPERATIVE VARIABLES IN 47 SURVIVORS AND 12 NONSURVIVORS OF OPEN-HEART OPERATIONS FOR MITRAL VALVE REPLACEMENT IN PATIENTS MORE THAN 65 YEARS OLD-SEPTEMBER, 1968, TO AUGUST, 1973 Survivors Nonsurvivors Variable (%) (%) Functional Class IV Primarily mitral stenosis Primarily mitral regurgitation Combined mitral stenosis & mitral regurgitation Atrial fibrillation Normal sinus rhythm Previous myocardial infarction Associated coronary disease Coronary angiography performed VOL. 18, NO. 1, JULY,

6 BARNHORST ET AL. TABLE 7. OPERATIVE VARIABLES IN 47 SURVIVORS AND 12 NONSURVIVORS OF OPEN-HEART OPERATIONS FOR MITRAL VALVE REPLACEMENT IN PATIENTS MORE THAN 65 YEARS OLD-SEPTEMBER, 1968, TO AUGUST, 1973 Variable Mean operating time Hypotension before bypass Mean bypass time Mean ischemia time Bypass rhythm Arrest & beating Arrest & ventricular fibrillation Ventricular fibrillation Hypotension after bypass RVY/LVP > 0.4 Survivors Nonsurvivors 3.7 hr. 3.8 hr. 6.5% 8.3% 1.1 hr. 1.5 hr min min /, 74.5% 2.1% 34.0% 48.7y0 8.3% 75.0y0 16.7% 41.7% 45.5y0 seen in the general population, probably because these patients had faradvanced disease and many had postmyocardial infarction mitral regurgitation. No patient with mitral stenosis alone died after mitral valve replacement. The data suggest a relationship between ventricular fibrillation during bypass and mortality, but there were too few patients to draw statistical conclusions. As with patients who had aortic valve replacement, the incidence of complications after mitral valve replacement was higher for patients who did not survive the operation. Survivors and nonsurvivors of each type of operation probably had equal incidences of coronary artery disease. Whether survivors and nonsurvivors had disease of equal severity could not be determined; however, the higher incidence of myocardial infarctions among nonsurvivors in all groups indicates that coronary artery disease was probably more severe in patients not surviving operation. The high mortality rate associated with multiple valve replacements is disappointing. Equal numbers of survivors and nonsurvivors were in Functional Class IV, but some indication of the severity of disease in these patients is that 47y0 of survivors and 430/, of nonsurvivors required inotropic or bypass support at the conclusion of the operation. Of statistical TABLE 8. POSTOPERATIVE COMPLICATIONS IN 47 SURVIVORS AND 12 NONSURVIVORS OF OPEN-HEART OPERATIONS FOR MITRAL VALVE REPLACEMENT IN PATIENTS MORE THAN 65 YEARS OLD- SEPTEMBER, 1968, TO AUGUST, 1973 Complication Dysrhy thmia Low cardiac output Myocardial infarction Cerebrovascular Renal Pulmonary Sepsis Survivors Nonsurvivors (%) (%) THE ANNALS OF THORACIC SURGERY

7 Open-Heart Surgery in Older Patients significance among the operative variables in these patients was the use of ventricular fibrillation during bypass in more of the nonsurviving patients. No conclusions can be drawn from our results in the group with combined valve replacement and coronary artery bypass grafting. The total mortality of 23.1y0 (22yo for aortic valve replacement and coronary artery bypass grafting and 25y0 for mitral valve replacement and coronary artery bypass grafting) did not lower the mortality of valve replacement alone. Comparing patients who had coronary grafts plus valve replacement with those who had valve replacement alone is difficult because of the incomplete assessment of coronary anatomy in many patients undergoing valve replacement alone. Two of the 3 deaths in the group with combined valve replacement and coronary artery bypass grafting were related to coronary artery disease, and this casts some doubt on the belief that the use of routine coronary arteriography and the grafting of significant coronary lesions will lower the mortality rate [9]. Our current practice is not to assess or to repair coronary arteries unless the patient has prominent symptoms of myocardial ischemia. The potential gain in early survival from grafting anatomically threatening coronary lesions may be counterbalanced by the increased mortality attendant on the combined procedure in patients older than 65 years of age. The role of prophylactic coronary artery bypass grafting in improving late operative results remains to be defined. Reduction of operative mortality for patients older than 65 years of age should result from earlier operation (that is, before Class IV status is reached), careful protection of the myocardium intraoperatively, and vigorous treatment of low cardiac output after operation. Myocardial protection includes good coronary perfusion, avoidance of ventricular fibrillation when possible, and moderate myocardial cooling when indicated. Although aortic valve replacement can be safely performed without coronary perfusion on many patients in the general population, good intraoperative coronary perfusion was associated with better operative survival in patients 66 years old or older. The potentially deleterious effects of ventricular fibrillation on subendocardial blood flow have been reported [4, 111. Significantly more nonsurvivors of multiple valve replacement operations were maintained in ventricular fibrillation during their operations. Similarly, more patients who died after mitral valve replacement were in ventricular fibrillation during operation, although the few patients involved did not permit statistical comparison. The high incidence of low cardiac output after these procedures may be related partly to subendocardial ischemia. These data suggest that avoiding intraoperative ventricular fibrillation and maintaining a beating heart, when possible, may improve operative results. References 1. Ahmad, A,, and Starr, A. J. 31:322, Valve replacement in geriatric patients. Br. Heart VOL. 18, NO. 1, JULY,

8 BARNHORST ET AL. 2. Ashor, G. W., Meyer, B. W., Lindesmith, G. G., Stiles, Q. R., Walker, G. H., and Tucker, B. L. Coronary artery disease: Surgery in 100 patients 65 years of age and older. Arch. Surg. 107:30, Austen, W. G., DeSanctis, R. W., Buckley, M. J., Mundth, E. D., and Scannell, J. G. Surgical management of aortic valve disease in the elderly. J.A.M.A. 211:624, Buckberg, G. D., Towers, B., Paglia, D. E., Mulder, D. G., and Maloney, J. V. Subendocardial ischemia after cardiopulmonary bypass. J. Thorac. Cardiovasc. Surg. 64:669, Carlson, R. G., Shafer, R. B., Eliot, R. S., Sellers, R. D., and Lillehei, C. W. Results of cardiac surgery in 273 older patients. Geriatrics 22:173, Danielson, G. K., Oxman, H. A., Connolly, D. C., Wallace, R. B., Pluth, J. R., and McGoon, D. C. Nine year experience with Starr-Edwards aortic valve replacement (abstract). Am. J. Cardiol. 31: 127, Duvoisin, G. E., and McGoon, D. C. Aortic valve replacement with a ballvalve prosthesis: Detailed analysis of early and late results. Arch. Surg. 99:684, Finegan, R. E., Gianelly, R. E., and Harrison, D. C. Aortic stenosis in the elderly: Relevance of age to diagnosis and treatment. N. Engl. J. Med. 281:1261, Guthrie, R. B., Spellberg, R. D., Benedict,.J. S., and Buhl, T. L. Openheart valve surgery in patients 65 and older. Arch. Surg. 105:42, Killen, D. A., and Collins, H. A. Open heart surgery beyond the sixth decade of life. South. Med. J. 65:397, Lufschanowski, R., and Leachman, R. D. Ventricular contraction-an important adjunct to sub-endocardial perfusion (editorial). Chest 63:653, Oxman, H. A., Connolly, D. C., McGoon, D. C., Wallace, R. B., Danielson, G. K., and Pluth, J. R. Ten year experience with isolated Starr-Edwards mitral valve replacement (abstract). Am. J. Cardiol. 29:284, Discussion DR. JACK J. GREENBERG (Miami Beach, Fla.): Dr. Barnhorst and his colleagues from the Mayo Clinic have again presented an excellent review of their experience, this time involving cardiac surgery in patients over 65 years old. This magic age was chosen by the authors, as well as our government friends, to indicate entrance into the elderly bracket. The authors set out to accomplish two goals: (1) to identify mortality statistics in the above-65 age group, and (2) to identify the factors that might be implicated as causes of mortality. The statistics they report indicate that operative mortality for valve and coronary artery surgery at the Mayo Clinic, although higher than that of their total population group, is certainly satisfactory. The 2074 mortality for mitral valve replacement reflects a significant number of patients whose operations were for coronary artery disease, and it is of note that in this above45 group, no patient who had had mitral valve replacement for rheumatic disease alone died. At the risk of being accused of presenting another paper, I w.ould like to discuss our experience in Miami with operations in the over-65 age group. I think our statistics are quite comparable with the Mayo Clinic s, and they support their finding that in patients over 65 the hospital mortality is very close to that of the general population below age 65. As in the authors series, we found that in aortic valve replacement for aortic stenosis there is a higher mortality among patients with aortic stenosis rather than aortic insufficiency. This is due to several factors, and it is in this group of patients that we attempt to keep a beating heart and concur with the authors 88 THE ANNALS OF THORACIC SURGERY

9 1 Open-Heart Surgery in Older Patients that avoidance of ventricular fibrillation in aortic valve replacement is important. The fact that mitral valve replacement in our series was done with elective ventricular fibrillation certainly does not indicate that myocardial protection cannot be given with ventricular fibrillation, however. In addition to identifying causes of mortality, it is most important to assess hemodynamic results in patients undergoing cardiac surgery. I think it must be recognized that hemodynamic factors improve less well in the older age group than in younger patients. The authors have admirably achieved their objectives, they have reported excellent operative statistics, and they have revealed areas of patient management that will aid all of us in dealing with the older cardiac patient. DR. GEORGE B. WISOFF (New Hyde Park, N.Y.): I would like to report on a few patients who haven t the air fare to make it from New York to Miami or the May.0 Clinic and just make a few comments about technique. We too believe that prolongation of useful life is a desirable goal in treatment of the elderly. In 44 patients with coronary disease who were over the age of 65 and were operated on, the preoperative and postoperative clinical and physiological status has been the same as in the younger group, except for more advanced symptomatic classification. Probably this was due to delayed physician referral. We analyzed the patients over the age of 70 and found that we had 24 more women than men. Again, aortic valve replacement was predominant. Hospital deaths in the over-70 group were similar to the experiences reported already. Altogether, within nearly two years we have lost 25% of these older patients. We believe technical factors are very important. Because of heavy calcification, we find that it is usually impossible to cannulate the coronary artery in the over-70 group, so we don t even try. The aorta closure usually requires buttressing sutures because of heavy calcification. I would question the authors about any of the technical factors that might be important in the management of this elderly group. DR. VIKING 0. BJORK (Stockholm, Sweden): I congratulate the authors on their excellent research results in older patients, which justify extension of the indications for operation in this group. In order to compare the hemodynamic effect of aortic valve replacement in two age groups-above and below 60 years-henze evaluated left ventricular pump function at rest and during exercise in 11 patients 60 to 68 years of age before and seven months after operation with the Bjiirk-Shiley tilting-disc valve. The left ventricular enddiastolic pressure, end-systolic pressure, and systolic stroke work were of equal magnitude and diminished to the same extent in both groups, indicating an adequate unloading of the left ventricle. Stroke work index was lower in the over-60 group, as was the change in stroke volume per unit change in left ventricular end-diastolic pressure. This indicates a higher degree of myocardial stiffness in the older patients but an equal improvement in left ventricular pump function in both groups followinq valve replacement. The 60- year-old myocardium begins to lose some of its ability to recover from prolonged overwork, but aortic valve replacement brings about an identical improvement in left ventricular pump function in both young and old patients. I think the observation of better results in patients not having ventricular fibrillation durilig operation is very interesting. We like to keep the heart pumping with coronary perfusion, and I also like the idea of including patients above 60 or 65 in the younger middle-age group. VOL. 18, NO. 1, JULY,

10 BARNHORST ET AL. DR. BARNHORST: I wish to thank the discussants for their comments. In reply to Dr. Greenberg s remarks about ventricular fibrillation, I share his view that in the relatively nonhypertrophied heart, ventricular fibrillation is likely not to cause any significant problems. I think that ample experimental data now available give reasonably conclusive evidence that it is the heavily hypertrophied heart in which prolonged electric fibrillation is harmful. I would also like to compliment both Dr. Greenberg and Dr. Wisoff far their excellent results. We found, in contrast to Dr. Wisoffs experience, that the majority of patients undergoing aortic valve replacement were able to have coronary artery perfusion without difficulty, and I still think it is preferable. We are able to keep a beating heart throughout the procedure, and even in those patients who fibrillate in spite of good coronary perfusion, we are able then to defibrillate the heart electrically and maintain a beating heart through the remainder of the procedure. We suspect this is helpful, although the evidence is not hard and fast. Dr. Wisoff, we also encountered more technical problems in elderly patients when closing the aortotomy. A particular problem in all these patients is the ventricular vent site, and we have learned to buttress that fairly carefully with Teflon-felt pledgets to ensure good closure and less tearing of the adjacent myocardium. I would like to compliment Professor Bjork on his excellent hemodynamic data. It is obviously important to have good objective information to warrant the increased risk in patients of this age group. 90 THE ANNALS OF THORACIC SURGERY