Valve replacement should not be performed in all asymptomatic patients with severe aortic incompetence

J THoRAc CARDIOVASC SURG 79:163-172, 1980

Valve replacement should not be performed in all asymptomatic patients with severe aortic incompetence Shahbudin H. Rahimtoola, M.B., F.R.C.P., Portland, Ore.

Since 1959, valve replacement has been the most important advance in the management of patients with valvular heart disease. 1 If aortic valve replacement (AVR) is successful and uncomplicated, many patients experience an improvement in symptomatic state":'" and, therefore, in the quality of life. The compensatory mechanisms of left ventricular (L V) hypertrophy and/ or dilatation regress;" 3. 16-18 and impaired ventricular performance improves.v 3, 19-21 The role of AVR in controlling infection and heart failure in infective endocarditis is established'<" and, therefore, its role in prolonging life seems reasonable. This probably also applies to patients with severe aortic stenosis in heart failure." These brilliant results of AVR cannot be applied automatically to asymptomatic patients with severe aortic incompetence. If one wanted to evaluate the role of AVR in the latter patients, theoretically one should be able to tally up the results of medical and operative therapy for severe aortic incompetence from the literature and to come to a firm conclusion as to whether or not AVR is superior to no surgical procedure. Unfortunately, such a comparison is not possible because of many problems associated with analysis of published data (Table I); hence the need for the current debate. Valve replacement is usually performed for relief of symptoms. In asymptomatic patients the reasons for AVR must be different-is it performed to prolong life, to preserve LV function, or to preserve the asymptomatic state for a longer period of time? It is reasonable that those who recommend AVR for asymptomatic patients with aortic incompetence state the goals of therapy, the importance of such goals, the proof that From the Division of Cardiology, Department of Medicine, University of Oregon Health Sciences Center, Portland, Ore. Address for reprints: Shahbudin H. Rahimtoola, M.D., University of Oregon Health Sciences Center, 3181 S.W. Sam Jackson Park Rd., Portland, Ore. 97201. 0022-5223/80/020163+ 10$01.00/0

these goals can be achieved, and the risks associated with achieving these goals (Table II). I will discuss the known problems associated with AYR. Known results of AVR

Before recommending AVR for these asymptomatic patients one must evaluate the following important factors": (l) operative mortality rate; (2) perioperative myocardial infarction; and (3) the proven 10 year record of valve replacement devices. The operative mortality rate for AVR varies considerably. Studies published in the years 1975 to 1979 from leading centers in the United States and abroad show an AVR operative mortality rate of 3% to 12%.5-14,28,29 An estimate of 5% to 7% is reasonable. Perioperative myocardial infarction is a problem. 2i, 30-3i It damages the myocardium and impairs LV function-a paradox if the goal is to preserve LV myocardium. Its incidence is underestimated by electrocardiographic (ECG) criteria.i"- 39 and although it occurs more often in patients with associated coronary artery disease, it also occurs in those without associated coronary artery disease. 36 The amount of LV hypertrophy in patients with severe aortic incompetence is about the same as in patients with severe aortic stenosis, 1 t L V mass is two to three times normal, 1 i and thus myocardial preservation during operation is of critical importance in such patients. 30-3i Use of hypothermic cardioplegia during operation has reduced the incidence of perioperative myocardial infarctiorr'?: sr, 40-42 and it also appears effective in preserving LV systolic pump function even with ischemic times exceeding 90 minutes,* although other data suggest that it may not be as effective with ischemic times exceeding 70 minutes. 43 Clearly more work needs to be *Harlan BJ, DeMots H, Murphy E, Rahimtoola SH, Starr A: Left ventricular function following aortic valve replacement using cold cardioplegia arrest with ischemic periods over ninety minutes (unpublished observations).

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Table I. Some problems associated with analysis of published data Patients with AS, AS! AI, and AI frequently not separated Criteria of assessment of severity of lesion not stated Quantitative LV function data not obtained Complications excluded in analysis of results; i.e .. operative mortality rate, perioperative myocardial infarction, bleeding with anticoagulants, prosthetic endocarditis 5. Life-table analyses not performed 6. If life-table analyses performed, standard error (or confidence limits) not presented; so-called event-free curves include some complications

1. 2. 3. 4.

Legend: AS. Aortic stenosis. AI. Aortic incompetence. LV. Left ventricular.

Table II. Recommendations supporting A VR for asymptomatic patients with severe AI I. 2. 3. 4.

Goals of therapy Importance of such goals Proof that these goals can be achieved Risks associated with achieving these goals

Legend: AVR, Aortic valve replacement.

Table III. Status of patients IO years after aortic valve replacement* Status

Dead Perioperative myocardial infarction Reoperation Thromboembolism Major hemorrhage with anticoagulants Minor hemorrhage with anticoagulants Prosthetic endocarditis

Percent 40-60 ~5

10-20 10-20 10-15 20-30 10

'Probably only one device - a ball and cage valve - has a published IO-year record." This table is, therefore, derived from a consideration of: (I) dozens of publications'S; (2) some extrapolation of data; and (3) recognition that with recent devices and berter therapy some complications occur less often; all of which only serve to emphasize that more data are needed and. therefore. one must be cautious in recommending AVR for asymptomatic patients.

done in this area.i'": sr. H Currently, a reasonable estimate of perioperative myocardial damage is 5% or greater. The proven IO year record of AVR is very good if AVR is undertaken in moderately or severely symptomatic patients with severe aortic stenosis or severe aortic incompetence. Little comfort is derived from contemplating this record (Table III) for asymptomatic patients. It needs to be emphasized that these results are known for only some mechanical prostheses:" and that the long-term results (2:5 years) with use of porcine valves (the most commonly used bioprosthesis in the United States) are not known. A recent publication concluded that the Hancock porcine xenograft "has

been a durable heart valve in excess of six years' ';8 however, it should be noted that in that study only six patients had completed 5 years of follow-up. Porcine heterografts are attractive because patients with such devices do not need anticoagulant therapy if they are in sinus rhythm"; however, such patients are not free of the risk of thromboembolism," the incidence of which may be as high as 2% per year.:" albeit without use of anticoagulant therapy. It could be argued that the aforementioned known results of AVR are true for symptomatic patients who have undergone operation in the last 5 to 10 years and that the results could be or will be different in asymptomatic patients currently undergoing operation. The latter might well be true, but should it not be proven so by well-designed, proper protocols before introducing AVR for asymptomatic patients into routine clinical practice?'? Of the major complications associated with AVR, the implications of an operative death and of reoperation need some additional considerations. An operative mortality rate of 5% in asymptomatic patients means that one is exposing these patients to a 5% incidence of "sudden death" in the next 2 to 4 postoperative weeks. * Reoperation is usually needed for early and late prosthetic malfunctions and/or prosthetic complications, such as endocarditis. Reoperation can be performed at the same or a slightly higher mortality rate as compared to the initial operation, I. 8. 48. 49 a risk that cardiologists and cardiac surgeons consider acceptable. However, it is the patient who is taking the risk, not the cardiologist or cardiac surgeon. Reoperation can have a disastrous effect on the patient and the patient's family-a point that should not be forgotten. Should not the patient and his family be warned prior to the first A VR if use of a nondurable device is planned? It has recently been emphasized that all valve replacement devices are smaller than the normal human valve and the prosthesis the patient receives is also limited by the size of the valve ring and by the cavity in which the prosthesis lies, valve prosthesis-patient mismatch." Thus following AVR the patient with severe aortic incompetence will be left with L V outflow obstruction that usually is mild to moderate and occasionally could be severe. AVR is a palliative procedure and not a curative one, as is ligation or division of a patent ductus arteriosus. It also differs from another palliative procedure-coro*Melvin Cheitlin, M.D., and Bruce Brundage, M.D., of the University of California, San Francisco, first pointed this out to me when we were discussing the role of AVR for asymptomatic patients with severe aortic stenosis.

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nary bypass operation. If bypass grafts do not function properly and the native coronary artery is not damaged, the latter will leave the patient in an unchanged condition.P" By contrast, with A VR the patient becomes device dependent; if the prosthesis malfunctions, reoperation, disability, and even death often result. In brief, with valve replacement the patient is exchanging native valve disease for prosthetic valve disease, a fact that must not be forgotten when considering AVR, particularly for the asymptomatic patient with severe aortic incompetence in whom the superiority of A VR over medical therapy alone has not been demonstrated clearly. On the other hand, aortic insufficiency appears to be well tolerated by most patients for prolonged periods of time.·'l-55 The 10 year survival rate is at least 50%55 and most of the surviving patients may be free of complications. Conclusion No. 1. Given the albeit imperfect but relevant data, one would have to conclude that A VR is not clinically indicated for asymptomatic patients with severe aortic incompetence and normal L V systolic pump function (for example, ejection fraction). Is there a problem? The previous presentation cannot end this discussion because there is a clinical problem that must be considered. The problem is that patients with severe aortic incompetence may develop L V dysfunction while still asymptomatic or may have moderate LV dysfunction at the time of the first symptom. Unfortunately, we do not know: (1) how many patients will follow this course; (2) ways of predicting the individual patient who will follow this course; (3) whether this course could have been prevented by AVR; and (4) whether patients would function better with or without AYR. It is appropriate to discuss first some studies that are cited as demonstrating the rationale for early operation and then whether it is "too late" for AVR if one awaits onset of symptoms or LV dysfunction. Of studies that are often cited as reasons for early operation the report by Spagnuolo and colleagues'" showed that young patients with severe rheumatic aortic regurgitation could be separated into "high-risk" and "low-risk" subgroups. Patients with the triad of moderate to marked LV enlargement, two or three ECG abnormalities, and diastolic blood pressure <40 mm Hg, systolic pressure> 140 mm Hg, or both, were at 87% risk of angina, heart failure, or death within 6 years. Whether data from young patients with rheumatic aortic incompetence can be applied to older individuals with other forms of aortic incompetence is not

clear and these authors did not evaluate the state of LV function in their patients. Nevertheless, a subgroup at higher risk has been identified, but why is it that A VR cannot be performed at the time of the first symptoms in such patients? Smith and associates'" concluded that patients with rheumatic aortic regurgitation should be considered for operation if they have a history of heart failure (i.e., they are not asymptomatic) combined with ECG evidence of extreme LV hypertrophy or a cardiothoracic ratio of >0.60. This conclusion was based on the incidence of death before operation; however, data showing a favorable influence of operation in any subgroup of patients were not presented; and Braun and co-workers" showed the prognosis of patients after AVR to be related to the preoperative cardiothoracic ratio; those with a cardiothoracic ratio <0.56 fared significantly better than those with a cardiothoracic ratio ~0.56. There are two problems with the latter study as it relates to the subject under discussion: First, only operated patients were compared. Data were not presented to show better outcome in operated patients with a cardiothoracic ratio ::::::0.56 than in nonoperated patients with a cardiothoracic ratio of ::::::0.56. Second, a close examination of their Fig. 4 shows that most patients with a cardiothoracic ratio <0.56 had aortic stenosis, whereas most of those with a cardiothoracic ratio ~0.56 had aortic incompetence, and about 75% of the total number of patients had aortic stenosis. Therefore, when they compared patients with a cardiothoracic ratio <0.56 to those with a cardiothoracic ratio ~0.56, they, in effect, compared aortic stenosis (with some aortic incompetence) patients to patients with combined aortic incompetence/stenosis. Therefore, although their data are of considerable interest, they are not relevant to the present discussion. It may be advocated that the asymptomatic patient with severe aortic incompetence will only become symptomatic with onset of LV dysfunction, and therefore, it may be "too late" if one awaits symptoms. Our own data have shown that symptomatic patients with severe aortic incompetence may have normal or abnormal resting LV systolic pump functions"; therefore the onset of symptoms cannot be attributed automatically to an impaired resting LV systolic pump function, ergo, by implication, to an irreversible LV dysfunction. Even if one waits until LV dysfunction appears, then is it not "too late?" The results of AVR for severe aortic incompetence in the presence of LV dysfunction are not as good as those for severe aortic stenosis but are not dismal.!: 3 We have shown that in patients with severe aortic incompetence and moderate to severe LV dysfunction," AVR (1) can be performed with low

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operative mortality rate; (2) is associated with a 3 year survival of 70% if one excludes the two prosthetic thromboses in nonanticoagulated patients, and 61 % if one does not exclude these two patients; (3) is associated with significant reductions of LV end-diastolic pressure, volume, and mass; and (4) results in an improvement of LV systolic pump function in 50%. Further, our preliminary data on the relatively shortterm follow-up of a small number of patients has shown that survival following A VR in patients with severe aortic incompetence does not appear to be predictable by preoperative functional class, hemodynamics, or L V volumes and mass, but is significantly lower in those with moderate impairment of L V systolic pump function.P? The study does not compare the outcome of medically versus surgically treated patients with normal L V systolic pump function; therefore, the current data do not answer the question whether or not in many patients it may be "too late" to wait for onset of symptoms and/or LV dysfunction. Conclusion No.2. There are some patients with severe aortic incompetence who are asymptomatic and have impaired resting LV systolic pump function. Impaired L V systolic pump function at rest is an indication that the clinical deterioration of the patient may be progressing on a more rapid downhill course; therefore, it is reasonable that A VR should be considered to be clinically indicated in the asymptomatic patients with severe aortic incompetence and impaired resting LV systolic pump function. This conclusion is not based on hard facts; therefore, it must be considered tentative. Newer knowledge about surgical treatment and about advances in medical managernent'" may result in a change in this recommendation in this subgroup, or for that matter, in any subgroups of patients. If one undertakes A VR in asymptomatic patients for whom the clinical indication for A VR is not totally clear, then several questions arise-one of which is, "What device should be inserted?"\' 27. 61 This is an important question because, as already emphasized, with valve replacement the patient becomes device dependent. It is important that the search for better valve replacement devices be continued until the perfect or ideal device is found.!" Appropriately, new devices'": 63 or modifications of older devices'i"?" continue to be explored. However, these often have been associated with unpredicted problems, I such as silicone rubber ball variance, thromboembolic complications, stuck poppets with close-tolerance valves, cloth tear, excessive hemolysis, obstruction of a nonanticoagulated aortic prosthesis, poppet escape, sudden prosthetic thrombosis, valve malfunction, valve degeneration and severe fibrocalcific obstruction of a heterograft

valve. 11. 67-7:) This list only emphasizes that introduction of a new device or a new model of an older prosthesis, even with small changes, may lead to complications that are unpredictable or do not become apparent for several years. Therefore, it is appropriate and most reasonable that the prosthesis chosen for insertion in these asymptomatic patients should have a proven "track record" of at least 5 to I0 years but preferably of I0 years or more. Other recent studies There are several recent studies from the National Institutes of Health that need to be mentioned. Borer and colleagues H showed that some asymptomatic patients with aortic regurgitation and normal ejection fraction at rest as determined by radionuclide ventriculography, had a reduction of ejection fraction on exercise. The frequency and significance of this finding need to be elucidated further. A preliminary study by Bonow and co-workers:" showed that late deaths owing to heart failure after A VR for aortic incompetence occurred in patients with echocardiographically (Mmode) determined ejection fraction of :s63% and LV end-systolic dimension of ~53 mm. In another preliminary study, Bonow and co-workers" concluded that operation should be considered in patients with LV end-systolic dimension of >55 mm on M-mode echocardiography, even in the absence of symptoms. On the other hand, the study of Krayenbuehl and associates" from Zurich, Switzerland, shows that the results of A VR in severe aortic incompetence cannot be predicted preoperatively from any M-mode echocardiographic criteria including LV end-systolic dimension of ~55 mm. Conclusions In asymptomatic patients with severe aortic incompetence, A VR (1) is not clinically indicated if LV systolic pump function is normal and (2) is indicated if resting LV systolic pump function is impaired. More clinical investigation of both of these subgroups of patients is needed. More information is needed before even a tentative conclusion can be reached in patients with normal resting but impaired exercise LV ejection fraction, and in patients with LV end-systolic dimension, on M-mode echocardiography, of ~53 to 55 mm or an ejection fraction on M-mode echocardiography of <63%. REFERENCES Rahimtoola SH: Valve replacement-a perspective. Am J Cardiol 35:711-715, 1975 2 Smith N. McAnulty J. Rahimtoola SH: Severe aortic ste-

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nosis with impaired left ventricular function and clinical heart failure. Results of valve replacement. Circulation 58:255-264. 1978 3 Clark DG. McAnulty 1. Rahimtoola SH: Results of valve replacement in aortic incompetence with left ventricular dysfunction. Circulation (in press) 4 Bristow lD, Kremkau EL: Hemodynamic changes after valve replacement with Starr-Edwards prosthesis. Am 1 Cardiol 35:716-724. 1975 5 Barnhorst DA. Oxman HA. Connally DC, Pluth lR, Danielson GK, Wallace RB, McGoon DC: Long-term followup of isolated replacement of the aortic or mitral valve with the Starr-Edwards prostheses. Am 1 Cardiol 35:228-233, 1975 6 Starr A, Grunkemeier G, Lambert L, Okies lE, Thomas D, Sugimura S, Lefrak EA: Aortic valve replacement. A ten-year followup of non-cloth-covered versus clothcovered caged-ball prostheses. Circulation 56:Suppl 2: 133-139, 1977 7 Copeland lG, Griepp RB, Stinson EB, Shumway NE: Long-term follow-up after isolated aortic valve replacement. 1 THoRAc CARDIOVASC SURG 74:875-889, 1977 8 Cohn LH, Koster lK, Mee RBBB, Collins 11 lr: Longterm followup of the Hancock bioprosthetic heart valve. A 6-year review. Circulation 60:Suppl 1:87-92, 1979 9 Lee SlK, Barr C, Callaghan rc, Rossall RE: Long-term survival after aortic valve replacement using SmeloffCutter prosthesis. Circulation 52: 1132-1137, 1975 10 Bjork VO, Henze A: Experience of more than 1000 implanted Bjork-Shiley heart valves over a six and one-half year period, Late Results of Valvular Replacements and Coronary Surgery, G Stalpaert , R Suy, F Vermeulen, eds., Ghent, Belgium, 1976, European Press, p 9 II Blackstone EH. Kirklin lW, Pluth lR. Turner ME, Parr GVS: The performance of the Braunwald-Cutter aortic prosthetic valve. Ann Thorac Surg 23:302-318, 1977 12 Barratt-Boyes B, Roche AHG, Whitlock RML: Six-year review of the results of free-hand aortic valve replacement using an antibiotic sterilized homograft valve. Circulation 55:353-361, 1977 13 Thompson R, Knight E, Ahmed M, Somerville W, Towers M, Yacoub M: The use of "fresh", unstented homograft valves for replacement of the aortic valve. Analysis of 6'/2 years experience. Circulation 56:837-841, 1977 14 Ionescu MI, Tandon AP, Mary DAS, Alsid A: Heart valve replacement with the Ionescu-Shiley pericardial xenograft. 1 THoRAc CARDIOV ASC SURG 73: 31-42, 1977 15 Rahimtoola SH: The problem of valve prosthesis-patient mismatch. Circulation 58:20-24, 1978 16 Kennedy lW, Doces 1, Stewart DK: Left ventricular function before and following aortic valve replacement. Circulation 56:944-950, 1977 17 Pantely G, Morton Ml , Rahimtoola SH: Effects of successful, uncomplicated valve replacement on ventricular hypertrophy, volume, and performance in aortic stenosis and aortic incompetence. 1 THoRAc CARDIOVASC SURG 75:383-391, 1978 18 Gaasch WH, Andrias CW, Levine Hl: Chronic aortic

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regurgitation. The effect of aortic valve replacement on left ventricular volume, mass and function. Circulation 58:825-836, 1978 Croke RP, Pifarre R, Sullivan H, Gunnar R, Loeb H: Reversal of advanced left ventricular dysfunction following aortic valve replacement for aortic stenosis. Ann Thorac Surg 24:38-43, 1977 Schwarz F, Flameng W, Thormann 1, Sesto M, Langebartels F, Hehrlein F, Schlepper M: Recovery from myocardial failure after aortic valve replacement. 1 THoRAc CARDIOVASC SURG 75:854-864, 1978 Krayenbuehl HP, Turina M, Hess OM, Rothlin M, Senning A: Pre- and postoperative left ventricular contractile function in patients with aortic valve disease. Br Heart 1 41:204-213, 1979 Wise lR lr, Cleland WP, Hallidie-Smith KA, Bentall HH, Goodwin IF, Oakley CM: Urgent aortic valve replacement for acute aortic regurgitation due to infective endocarditis. Lancet 2: 115-121, 1971 Wilson WR, Danielson GK, Giuliani ER, Washington lA II, Jaumin PM, Geraci lE: Valve replacement in patients with active infective endocarditis. Circulation 58:585588, 1978 Richardson rv, Karp RB, Kirklin rw. Dismukes WE: Treatment of infective endocarditis. A IO-year comparative analysis. Circulation 58:589-597, 1978 McAnulty lH, Rahimtoola SH: Surgery for infective endocarditis. lAMA 242:77-79, 1979 Okies lE, Starr A: Cardiac surgery in infective endocarditis, Infective Endocarditis, SH Rahimtoola, ed., New York, 1978, Grune & Stratton, Inc., pp. 361-377 Rahimtoola SH: Early valve replacement for preservation of ventricular function? Am 1 Cardiol 40:472-475, 1977 Daenen W, Stalpaert G: Experience with the Bjork-Shiley prosthesis (365 cases), Late Results of Valvular Replacement and Coronary Surgery, G Stalpaert, R Suy, F Vermeulen, eds., Ghent, Belgium, 1976, European Press, p 47 Karp RB, Kirklin lW, Kouchoukos NT, Pacifico AD: Comparison of three devices to replace the aortic valve. Circulation 50:Suppl 2:163-169, 1974 Kirklin lW, Conti VR, Blackstone EH: Prevention of myocardial damage during cardiac operations. N Engl 1 Med 301: 135-141, 1979 Hultgren HN, Miyagawa M, Buch W, Angell WW: Ischemic myocardial injury during cardiopulmonary bypass surgery. Am Heart 1 85:167-176, 1973 Berndt TB, Hancock EW, Shumway NE, Harrison DC: Aortic valve replacement with and without coronary artery bypass surgery. Circulation 50:967-971, 1974 Sapsford RN, Blackstone EH, Kirklin lW, Karp RB, Kouchoukos NT, Pacifico AD, Roe CR, Bradley EL: Coronary perfusion versus cold ischemic arrest during aortic valve surgery Circulation 49:1190-1199,1974 Rossiter S1, Hultgren HN, Kosek lC, Wuerflein RD, Angell WW: Myocardial damage in combined valvular and coronary bypass surgery. Circulation 52: Suppl 1:119-125, 1975

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35 Berger Rl, Karp RB, Kouchoukos NT: Valve replacement and myocardial revascularization. Circulation 52: Suppl 1:126-131, 1975 36 Murphy ES, Rosch 1, Rahimtoola SH: Frequency and significance of coronary arterial dominance in isolated aortic stenosis. Am 1 Cardiol 39:505-509, 1977 37 Harlan Bl, Starr A: Myocardial preservation, Manual of Cardiac Surgery, New York, Springier-Verlag, Inc. (in press) 38 Righetti A, Crawford MH, O'Rourke RA, Hardarson T, Schelbert H, Daily PO, DeLuca M, Ashburn W, Ross 1 lr: Detection of perioperative myocardial damage after coronary artery bypass graft surgery. Circulation 55: 173-178,1977 39 Klausner SC, Botvinick EH, Shames D, Ullyot nr, Fishman NH, Roe BB, Ebert PA, Chatterjee K, Parmley WW: The application of radionuclide infarct scintigraphy to diagnose perioperative myocardial infarction following revascularization. Circulation 56: 173-181, 1977 40 Adams PX, Cunningham lN, Trehan NK, Brazier lR, Reed GE, Spencer FC: Clinical experience using potassium-induced cardioplegia with hypothermia in aortic valve replacement. 1 THoRAc CARDIOVASC SURG 75:564-568, 1978 41 Conti VR, Bertranou EG, Blackstone EH, Kirklin lW, Digerness SB: Cold cardioplegia versus hypothermia for myocardial protection. Randomized clinical study. 1 THORAC CARDIOVASC SURG 76:577-589, 1978 42 Richardson rv, Kouchoukos NT, Wright 10, Karp BB: Combined aortic valve replacement and myocardial revascularization. Results in 220 patients. Circulation 59:75-81, 1979 43 Ellis Rl, Gertz EW, Wisneski 1, Ebert PA: Mild ventricular dysfunction following cold potassium cardioplegia. Circulation 60:Suppl 1:147-150, 1979 44 Hoffman liE: Determinants and prediction of transmural myocardial perfusion. Circulation 58:381-391, 1978 45 Lefrak EA, Starr A: Cardiac Valve Prostheses, New York, 1979, Appleton-Century-Crofts, Inc. 46 Stinson EB, Griepp RB, Oyer PE, Shumway NE: Longterm experience with porcine aortic valve xenografts. 1 THORAC CARDIOVASC SURG 73:54-63, 1977 47 Rahimtoola SH: Coronary arteriography in asymptomatic patients after myocardial infarction: The need to distinguish between clinical investigation and clinical care. Chest (in press) 48 Macmanus Q, Okies lE, Phillips Sf , Starr A: Surgical considerations in patients undergoing repeat median sternotomy. 1 THoRAc CARDIOVASC SURG 69:138-143,1975 49 English TAH, Milstein BB: Repeat open intracardiac operation. Analysis of fifty operations. J THORAC CARDIOVASC SURG 76:56-60, 1978 50 Bonchek L1, Rahimtoola SH, Chaitman BR, Rosch 1, Anderson RP, Starr A: Vein graft occlusion. Immediate and late consequences and therapeutic implications. Circulation 50:Suppl 2:84-97, 1974 51 Segall, Harvey WP, Hufnagel C: A clinical study of

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one-hundred cases of severe aortic insufficiency. Am 1 Med 21 :200-210, 1956 Bland EF, Wheeler EO: Severe aortic regurgitation in young people. A long-term perspective with reference to prognosis and prosthesis. N Engl 1 Med 256:667-672, 1957 Rotman M, Morris 11 Jr. Behar VS, Peter RH, Kong Y: Aortic valvular disease. Comparison of types and their medical and surgical management. Am 1 Med 51:241256, 1971 Goldschlager N, Pfeifer 1, Cohn K, Popper R, Selzer A: The natural history of aortic regurgitation. Am 1 Med 54:477-488, 1973 Rapaport E: Natural history of aortic and mitral valve disease. Am 1 Cardiol 35:221-227, 1975 Spagnuolo M, Kloth H, Taranta A, Dotle E, Pasternack E: Natural history of rheumatic aortic regurgitation. Circulation 44:368-380, 1971 Smith Hl , Neutze 1M, Roche AHG, Agnew TJ, BarrattBoyes BG: The natural history of rheumatic aortic regurgitation and the indications for surgery. Br Heart 1 38:147-154, 1976 Braun LO, Kincaid OW, McGoon DC: Prognosis of aortic valve replacement in relation to the preoperative heart size. 1 THORAC CARDIOVASC SURG 65:381-385, 1973 Greves 1, Clark D, Greenberg B, McAnulty 1, Starr A, Rahimtoola S: Late survival after valve replacement for severe isolated aortic incompetence (abstr). Am 1 Cardiol (in press) Greenberg B, DeMots H, Murphy E, Greves J, Kovaric T, Rahimtoola SH: Improved hemodynamics in patients with severe aortic insufficiency by afterload reduction using oral hydralazine (abstr). Clin Res 27:17IA, 1979 Roberts WC: Choosing a substitute cardiac valve. Type, size, surgeon. Am 1 Cardiol 38:633-644, 1976 Nitter-Hauge S, Enge I, Sembe BKH, Hall KV: Primary clinical experience with the Hall-Kaster valve in the aortic position. Circulation 60:Suppl 1:55-62, 1979 Emery RW, Mettler E, Nicoloff DM: A new cardiac prosthesis. The St. lude Medical cardiac valve. Circulation 60:Suppl 1:48-54, 1979 Bjork VO: The improved Bjork-Shiley tilting disc valve prosthesis. Presented at the meeting of the Pan-Pacific Surgical Society, Honolulu, April 7, 1978 Levine FH, Buckley Ml, Austen WG: Hemodynamic evaluation of the Hancock-modified orifice bioprosthesis in the aortic position. Circulation 58:Suppl 1:33-35, 1978 Craver 1M, King SB III, Douglas lS, Franch RH, lones EL, Morris DC, Kopchak 1, Hatcher CR lr: Late hemodynamic evaluation of Hancock-modified orifice aortic bioprothesis. Circulation 60:Suppl 1:93-97, 1979 Pluth lR, McGoon DC: Current status of heart valve replacement. Mod Cone Cardiovasc Dis 48:65-70, 1974 Brawley RK, Donahoo lS, Gott VL: Current status of the Beall, Bjork-Shiley, Braunwald-Cutter, Lillehei-Kaster and Smeloff-Cutter cardiac valve prostheses. Am 1 Cardiol 35:855-865. 1975

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69 Wallace RB: Tissue valves. Am 1 Cardiol 35:866-871, 1975 70 Duvoisin GE, Wallace RB, Ellis FH lr, Anderson MW, MeGoon DC: Late results of cardiac valve replacement. Circulation 38:Suppl 2:75-78, 1968 71 Stein DW, Rahimtoola SH. Kloster FE, Selden R, Starr A: Thrombotic phenomena with nonanticoagulated composite strut aortic prostheses. 1 THoRAc CARDIOVASC SURG 71:680-684, 1976 72 Kutsche LM, Oyer P, Shumway N, Baum D: An important complication of Hancock mitral valve replacement in children. Circulation 60:Suppl 2:98-103, 1979 73 Gray LA lr, Fulton RL, Srivastava TN, Flowers NC: Surgical treatment of thrombosed Bjork-Shiley aortic valve prosthesis. 1 THoRAc CARDIOVASC SURG 71:429432, 1976 74 Borer lS, Bacharach SL, Green MV, Kent KM, Henry WL, Rosing DR, Seides SF, Johnston GS, Epstein SE: Exercise-induced left ventricular dysfunction in symptomatic and asymptomatic patients with aortic regurgita-

Editor's comment: An alternative viewpoint One topic at the 1979 Annual Scientific Session of the American College of Cardiology, "Controversies in Cardiology," was titled "Valve Replacement Should be Performed in the Mildly Symptomatic Patient With Marked Chronic Aortic Regurgitation." I was asked to speak on the affirmative and Dr. Shahbudin Rahimtoola on the negative side of that topic. It is an important issue, and each of the speakers tried valiantly, in the interests of true debate, to emphasize his assigned perspective while realizing that no one really knows the answer at this time. As is noted in Dr. Rahimtoola's lucid editorial, and as indicated by a rephrasing of its title, he implies that valve replacement should possibly be performed for some asymptomatic patients with severe aortic incompetence. The problem lies in defining which patients should be selected for operation. Perhaps comment from a surgeon's vantage would also be of interest. We would all agree that any operation is indicated only when the operation provides better assurance of the patient's survival and well-being than would nonoperative management. Yet in clinical practice it is difficult to apply this truism to patients having significant aortic regurgitation. In the future this decisiom will be simplified. When replacement of the aortic valve carries negligible risk, and when a perfect substitute valve is developed, then the indication for valve replacement can be defined in essentially mathematical terms. Thus replacement of a regurgitant aortic valve would be indicated whenever a certain severity of re-

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tion. Assessment with radionuclide cineangiography. Am 1 Cardiol 42:351-357, 1978 Bonow RO, Henry WL, Kent KM, Borer lS, Redwood DR, Conkle DM, McIntosh CL, Morrow AG, Epstein SE: Predictors of late deaths due to congestive heart failure following operation for aortic regurgitation (abstr). Am 1 Cardiol 41 :382, 1978 Bonow RO, Henry WL, Epstein SE: Echocardiographic changes in asymptomatic patients with aortic regurgitation. Observations on the optimum time to operate (abstr). Circulation 57,58:Suppl 2:23, 1978 Turina 1, lenni R, Turina M, Krayenbuehl HP: Is echocardiography useful for predicting the late outcome of valve replacement in patients with chronic left ventricular volume overload? Presented at the meeting of the Working Group of European Society of Cardiology on Valvular Prosthesis, Lyon, France, Oct. I, 1979 Rahimtoola SH: Key references-outcome of aortic valve surgery. Circulation 60: 1191-1195, 1979

gurgitation had developed, as perhaps when the amount of regurgitation equalled 25% of the forward stroke volume. The present risk of operative death for the minimally disabled patient following aortic valve replacement by an experienced surgical team should be 2% or less. However, no current replacement valve has yet approached perfection. Questions of durability, thrombogenicity, or hemodynamic obstruction still surround each available substitute valve. Therefore, it is not now appropriate to advise operation solely on the basis that aortic valve regurgitation is causing a certain degree of mechanical inefficiency for the heart. It is necessary to consider other indications for operation. No one would favor operation for patients having mild regurgitation but no other objective or subjective abnormalities. At the other extreme, the notion that the valve should be replaced for essentially all patients who have experienced congestive heart failure or angina is almost unopposed. The question before us now, then, is the proper management for the patient with severe aortic regurgitation who still enjoys a rather full life, free of serious limitations. Should the valve be replaced, or should replacement be postponed until congestive failure or angina provides compelling indication for operation? The ideal solution to this problem would, at first reflection, be to conduct a randomized study. In practice, however, enthusiasm for such a randomized study drifts away upon the realization that the study would probably not be conclusive until a period of perhaps 20

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The Journal of Thoracic and Cardiovascular Surgery

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Fig. 1. Survival of asymptomatic patients having severe aortic regurgitation. A. Operation deferred until onset of symptomatic disability (A' if hypothesis true that prognosis is good and A 2 if prognosis is poor). B. Operation performed before symptomatic disability. years had elapsed, because the problems of durability or other complications of present prostheses may not become adequately manifest until then. During the time of such a study, if the past is indicative, the methods of operation will change and the types of substitute valves will also evolve. Thus a study launched now, though ultimately providing valid data, might be relegated to a status of irrelevance when completed. Most reviews of large series of patients show deterioration in the late result of aortic valve replacement with advancing preoperative disability. Thus in the review by Isom and associates' 5 year survival of Class III patients was 87% compared with 62% for Class IV, with hospital deaths excluded. Copeland and colleagues" found approximately 60% survival at 7 years for Class III and approximately 40% for Class IV patients, including hospital deaths." Most impressive were the results of Rubin and his co-workers" showing 91% survival at 12 years for Class I and II, 39% for Class III, and a smaller percentage for Class IV patients, among 212 operative survivors. Other invasive and noninvasive variables in the preoperative status of the patient could be cited to document that advanced disease adversely affects the late result of operation. A striking example is the postoperative survival of patients with preoperatively normal, moderately increased, and severely increased heart sizes, as determined by ratio of cardiac to thoracic diameter. The late survival rate of patients with normal preoperative heart size was nearly as good as that of the normal population of similar age." With respect to Dr.

Rahimtoola's critique of that study, it should be noted that "the survival curves of groups according to preoperative heart size do not differ significantly according to whether the valve was predominantly stenotic or incompetent. "4 Even if it would be generally accepted that the result of operation is poorer with advancing degrees of preoperative disability, as I think it is, this admittedly is not a conclusive argument by itself for earlier operation. The issue is not whether a better operative result can be provided the nondisabled patient having severe aortic regurgitation; rather the issue is whether the patient's longevity and well-being would be better served by early valve replacement or by deferring valve replacement. An attempt is made to portray this problem in Fig. 1. Let us assume a large group of not yet disabled patients are randomized as they first fulfill certain hypothetical criteria for establishing the diagnosis of severe aortic regurgitation. In Group A operation will be postponed until the patients become disabled, and in group B operation will be performed promptly while still undisabled. From data at hand, which we have just reviewed, we can be reasonably assured of a rather good long-term result for Group B and can hope for a 10 year survival rate of 80% to 85% as compared to the normal population for that age and sex. The outcome for Group A, the nonoperated cohort, is less certain. The extremes of possibilities would be represented by hypothetical courses A' and A 2 in Fig. 1. If A' were true, the nonoperated group with severe aortic regurgitation could expect an extended period of low-risk existence before the onset of disability, at which time (maybe 8 years or so) operation would be performed with a result curve only slightly less favorable for that Group B, so that by 10 years they would have better survivorship than Group B. At the opposite extreme, if A2 were the closer representation of reality, then Group A (not having early valve replacement) would be subject to a high risk of sudden death and also to the early onset of disability requiring early operation, and the result of operation would be seriously jeopardized by the delay in operation imposed upon Group A patients. Thus, the result at 10 years for Group A2 would be far inferior to that of the Group (B) undergoing early operation. This exercise in speculation emphasizes the importance of learning the natural course of patients with severe aortic regurgitation before they become disabled. Dr. Rahimtoola has reviewed such available studies (his reference Nos. 51 to 57). If we were to exclude patients with mild or moderate aortic regurgi-

Volume 79 Number 2 February, 1980

tation from the analysis, these studies would seem to predict a course more closely approximating A 2 than AI of our hypothetical schematic. It is timely now to look for a better indicator of the best time for valve replacement. The ideal indicator being sought is one defining an abnormality of left ventricular (LV) function which is independent of the ventricular loading abnormalities imposed by the aortic regurgitation itself. Thus the test would identify developing changes in L V function which are not reversible by valvular replacement. A list of possible potentially valuable preoperative variables includes the regurgitant fraction, LV histologic changes, mean velocity of circumferential fiber shortening (Vcf), LV diastolic compliance and stiffness coefficient, ejection fraction, percent change of LV dimensions, LV dimension itself at rest and under stress, and the ratio of LV volume to muscle mass. A remarkable outpouring of careful studies of the effectiveness of these variables has occurred recently, but their significance is difficult to define. For example, of 12 recently published studies dealing with LV ejection fraction in aortic regurgitation."?" seven have demonstrated that reduced ejection fraction preoperatively results in a poor prognosis for valvular replacement.s'!' three showed that a reduced ejection fraction preoperatively is improved by replacement of the valve,12-14 and two others showed that the ejection fraction may remain depressed postoperatively. 15. 16 The echocardiographic study of Cunha and associates!' showed, for example, marked deterioration in results for patients with decreased preoperative percent change in LV dimension. Similarly, of four studies of Vcf in patients with aortic valvular disease, two showed that a reduced preoperative Vcf tends to remain reduced postoperatively, 17. 18 and two showed that it tends to return to normal. 13. 14 Thus Dr. Rahimtoola's perspective as a cardiologist and my perspective as a surgeon have ended with the same conclusion: We are not yet ready to advise valvular replacement for the asymptomatic patient with severe aortic regurgitation if the left ventricle is hale and hearty, but we do advise valvular replacement when the L V myocardium is beginning to develop irreversible changes. Having reached this agreement, the task now is to develop far more precise guidelines for separating these two groups of patients. Dwight C. McGoon, M.D. REFERENCES Isom OW, Dembrow JM, Glassman E, Pasternack BS, Sackler JP, Spencer FC: Factors influencing long-term

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survival after isolated aortic valve replacement. Circulation 49,50:Suppl 2:154-162, 1974 2 Copeland JG, Griepp RB, Stinson EB, Shumway NE: Long-term follow-up after isolated aortic valve replacement. J THORAC CARDIOVASC SURG. 74:875-888, 1977 3 Rubin JW, Moore HY, Hillson RF, Ellison RG. Thirteen year experience with aortic valve replacement. Am J Cardiol 40:345-354, 1977 4 Braun LO, Kincaid OW, McGoon DC: Prognosis of aortic valve replacement in relation to the preoperative heart size. J THORAC CARDIOVASC SURG 65:381-385, 1973 5 Hammermeister KE, Chikos PM, Fisher L, Dodge HT: Relationship of cardiothoracic ratio and plain film heart volume to late survival. Circulation 59:89-95, 1979 6 Kennedy JW, Doces J, Stewart OK: Left ventricular function before and following aortic valve replacement. Circulation 56:944-950, 1977 7 Clark CE, Henry WL, Morganroth J, Pearlman AS, Grauer L, Redwood DR, Itscoitz SB, McIntosh CL, Michaelis LL, Morrow AG, Epstein SE: Influence of ejection fraction on the results of operation in aortic regurgitation. (abstr). Circulation 52:Suppl 2:169, 1975 8 O'Toole 10, Geiser EA, Reddy S, Curtiss EI, Landfair RM: Effect of preoperative ejection fraction on survival and hemodynamic improvement following aortic valve replacement. Circulation 58: 1175-1184, 1978 9 Thompson R, Ahmed M, Seabra-Gomes R, Ilsley C, Rickards A, Towers M, Yacoub M: The Influence of preoperative left ventricular function on the results of homograft replacement of the aortic valve for aortic regurgitation. J THORAC CARDIOVASC SURG 77:411-420, 1979 10 Gaasch WH, Andrias CW, Levine HJ: Chronic aortic regurgitation: The effect of aortic valve replacement on left ventricular volume, mass and function. Circulation 58:825-836, 1978 11 Cunha CLP, Giuliani ER, Fuster Y, Seward JP, Brandenburg RO, McGoon DC: Preoperative M-mode echocardiography as a predictor of surgical results in chronic aortic insufficiency. J THORAC CARDlOVASC SURG 79: 256-265, 1979 12 Schwarz F, Flameng W, Schaper J, Langebartels F, Sesto M, Hehrlein F, Schlepper M: Myocardial structure and function in patients with aortic valve disease and their relation to postoperative results. Am J Cardiol 41:661669, 1978 13 Schwarz F, Flameng W, Thormann J, Sesto M, Langebartels F, Hehrlein F, Schlepper M: Recovery from myocardial failure after aortic valve replacement. J THORAC CARDIOVASC SURG 75:854-864, 1978 14 Schuler G, Righetti A, Hardarson R, O'Rourke R, Peterson K, Johnson A, Daily P, Oury J, Ross J Jr: Serial studies on ventricular function following valve replacement for volume overload (abstr). Circulation 53,54: Suppl 2:104, 1976 15 Borer JS, Bacharach SL, Green MY, Kent KM, Rosing DR, Seides SF, McIntosh CL, Conkle OM, Morrow AG,

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Epstein SE: Left ventricular function during exercise before and after aortic valve replacement (abstr). Circulation 55,56:Suppl 3:28, 1977 16 Borer JS, Bacharach SL, Green MV, Kent KM, Henry WL, Rosing DR, Seides SF, Johnston GS, Epstein SE, Mack B: Exercise-induced left ventricular dysfunction in symptomatic and asymptomatic patients with aortic regurgitation. Assessment with radionuclide cineangiography. Am J CardioI42:351-357, 1978

The Journal of Thoracic and Cardiovascular Surgery

17 Gault JH, Covell JW, Braunwald E, Ross J Jr: Left ventricular performance following correction of free aortic regurgitation. Circulation 42:773-780, 1970 18 Pantely G, Morton M, Rahimtoola SH: Effects of successful, uncomplicated valve replacement on ventricular hypertrophy, volume, and performance in aortic stenosis and in aortic incompetence. J THORAC CARDIOVASC SURG 75:383-391, 1978

Information for authors Most of the provisions of the Copyright Act of 1976 became effective on January I, 1978. Therefore, all manuscripts must be accompanied by the following written statement, signed by one author: "The undersigned author transfers all copyright ownership of the manuscript (title of article) to The C. V. Mosby Company in the event the work is published. The undersigned author warrants that the article is original, is not under consideration by another journal, and has not been previously published. I sign for and accept responsibility for releasing this material on behalf of any and all co-authors." Authors will be consulted, when possible, regarding republication of their material.