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An appeal for data
L e t t e r s to the E d i t o r
by measurement of the cardiothoracic ratio. This difficulty has been noted before and it has been suggested by Simon 1 that rather than continue to use this ratio we should instead rely on absolute measurements of transverse heart diameter, i.e., the sum of the measurement of the furthest projections of the heart shadow to the right and left of the midline. Simon stated that "any heart larger than 15.5 cm. is probably a pathologically enlarged heart unless the patient is tall, very muscular, heavy, and in an occupation needing much muscular effort."' We have recently studied quantitatively various parameters of the chest radiographs of 100 normal individuals, including the transverse heart diameter, and find this to be true. ~ The distribution of heart size was found to follow a normal Gaussian pattern, with a range of 8.50 to 16.00 cm. in the male (median 12.5 cm.), and 9.5 to 14.00 cm. in the female (median 11 to 12 cm.). The only individual with a transverse heart diameter greater than 15.5 cm. was overweight (86 kilograms}, though not tall (163 cm.~. Thus. although the early enlargement of small hearts cannot be detected in this way, the use of such absolute criteria may go some way co solving Dr. Burch's problem. A d r i a n Williams. M.B., M.R.C.P. Clinical Lecturer Cardiothoracic Institute Brompton Hospital Fulham Rd. London S W 3 6HP England
REFERENCES 1.
Simon. G.: Principles of chest x-ray diagnosis. 3rd ed, London. 1971 Butterworth & Co.. Ltd. Williams. A. J.. and Simon. G.: Some parameters of the normal chest x-ray (In preparation)
An appeal for data To the Editor: For a biography of Dr. Alton Ochsner of Ochsner Clinic. New Orleans. opinions, evaluations, anecdotes, reminiscences. photos, and any other relevant material are urgently needed. Photos will be carefully handled and will be returned. All material will be gratefully received by Ira Harkey, Ph.D. 401 Metairie R o a d Apt. 706 Metairie. La. 70005
Survival after aortic valve replacement To the Editor: It is tragic that the importan~ question Which patients will benefit from cardiac valve replacement? continues to be shrouded in mystery because of poorly designed clinical trials and inaccurately reported results. Sufficient statistical methodology exists to allow clinical investigators to consider both the ethical responsibility co administer the best available therapy and the scientific responsibility to conduct a proper evaluation.' "'Advances in valve replacement have been impressive. However. excessive enthusiasm has swung the pendulum too far from center. The risk-benefit ratio is sometimes derived by
American Heart Journal
comparing an unrealistic expectation of success with the most pessimistic estimate of the natural course. ''~ The relevance of this editorial statement by Dr. Arthur Selzer is illustrated in "Long-term survival following aortic valve replacement" in the March, 1976, issue of the AMERICAN HEART JOURNAL. Dr. Roberts and his associates assert that survival of patients with symptomatic aortic stenosis and/or regurgitation is clearly improved when they have had replacement of the aortic valve? This premise is supported by a figure showing three lines, one purporting to show the "overall survival of the entire patient group," another representing the natural history of untreated aortic valve disease, and the third representing a comparison population. The line representing the "overall survival of the entire patient group" actually represents, at best, the "surviving patient group"; the 24 patients who constitute the hospital mortality group were not included. The text states that 18 of the initial 95 survivors of aortic valve replacement died within the first two years following surgery-a 19 per cent mortality rate; the figure shows this percentage at three years. The control group used for comparison with the patients surviving aortic valve replacement was taken from a study completed 21 years before the completion of the aortic valve replacement study?. 5 Doctors Gehan and Freireich' have warned "Using patients from a previous study could be misleading if a relatively long interval had elapsed between studies [say, greater than three years), or if it could be demonstrated that important changes had taken place in clinical investigators, type of patients or therapy. Patients from a previous study should not be used as selected controls in such circumstances and a randomized prospective study is recommended. ,,1 Dr. Roberts and his associates compared their patient group co patients receiving no treatment, which is only one of the three alternate choices-no treatment, less drastic surgical therapy, or medical management. A comparison can be made between the total surgical group and a group of medically treated patients (Fig. 1)2 This is an admittedly poor comparison as no attempt can be made to compare the patients in the ~wo groups as to severity of disease, etiology of disease, age, sex. or other important factors affecting mortality. The two groups can only be compared in that the patients in both groups were symptomatic. Though imprecise, this comparison of surgically treated patients and medically treated patients is in accord with Dr. Selzer's editorial statement that valve replacement clearly prolongs life in the middle-aged or elderly patient with aortic stenosis who is symptomatic and whose symptoms are related to valve obstruction. 2 However, no such conclusion is obvious for patients with aortic insufficiency. It is assumed that the mortality of the surgically treated patients is evenly distributed as Dr. Roberts and his associates report: "Survival in the stenotic, regurgitant, and combined groups was nearly identical. ''~ This statement is in contrast to the data in their Fig. 4 representing the survival of these groups which presents significantly greater mortality for the patients with aortic regurgitation alone and in combination with aortic stenosis than the mortality presented for patients with aortic stenosis alone. The important question remains unanswered. For which patients does cardiac valve replacement affect the natural history of valvular heart disease in a positive way? The National Heart and Lung Institute has allocated 51 million dollars for clinical trials in 1976.7 It is imperative that the
537
by measurement of the cardiothoracic ratio. This difficulty has been noted before and it has been suggested by Simon 1 that rather than continue to use this ratio we should instead rely on absolute measurements of transverse heart diameter, i.e., the sum of the measurement of the furthest projections of the heart shadow to the right and left of the midline. Simon stated that "any heart larger than 15.5 cm. is probably a pathologically enlarged heart unless the patient is tall, very muscular, heavy, and in an occupation needing much muscular effort."' We have recently studied quantitatively various parameters of the chest radiographs of 100 normal individuals, including the transverse heart diameter, and find this to be true. ~ The distribution of heart size was found to follow a normal Gaussian pattern, with a range of 8.50 to 16.00 cm. in the male (median 12.5 cm.), and 9.5 to 14.00 cm. in the female (median 11 to 12 cm.). The only individual with a transverse heart diameter greater than 15.5 cm. was overweight (86 kilograms}, though not tall (163 cm.~. Thus. although the early enlargement of small hearts cannot be detected in this way, the use of such absolute criteria may go some way co solving Dr. Burch's problem. A d r i a n Williams. M.B., M.R.C.P. Clinical Lecturer Cardiothoracic Institute Brompton Hospital Fulham Rd. London S W 3 6HP England
REFERENCES 1.
Simon. G.: Principles of chest x-ray diagnosis. 3rd ed, London. 1971 Butterworth & Co.. Ltd. Williams. A. J.. and Simon. G.: Some parameters of the normal chest x-ray (In preparation)
An appeal for data To the Editor: For a biography of Dr. Alton Ochsner of Ochsner Clinic. New Orleans. opinions, evaluations, anecdotes, reminiscences. photos, and any other relevant material are urgently needed. Photos will be carefully handled and will be returned. All material will be gratefully received by Ira Harkey, Ph.D. 401 Metairie R o a d Apt. 706 Metairie. La. 70005
Survival after aortic valve replacement To the Editor: It is tragic that the importan~ question Which patients will benefit from cardiac valve replacement? continues to be shrouded in mystery because of poorly designed clinical trials and inaccurately reported results. Sufficient statistical methodology exists to allow clinical investigators to consider both the ethical responsibility co administer the best available therapy and the scientific responsibility to conduct a proper evaluation.' "'Advances in valve replacement have been impressive. However. excessive enthusiasm has swung the pendulum too far from center. The risk-benefit ratio is sometimes derived by
American Heart Journal
comparing an unrealistic expectation of success with the most pessimistic estimate of the natural course. ''~ The relevance of this editorial statement by Dr. Arthur Selzer is illustrated in "Long-term survival following aortic valve replacement" in the March, 1976, issue of the AMERICAN HEART JOURNAL. Dr. Roberts and his associates assert that survival of patients with symptomatic aortic stenosis and/or regurgitation is clearly improved when they have had replacement of the aortic valve? This premise is supported by a figure showing three lines, one purporting to show the "overall survival of the entire patient group," another representing the natural history of untreated aortic valve disease, and the third representing a comparison population. The line representing the "overall survival of the entire patient group" actually represents, at best, the "surviving patient group"; the 24 patients who constitute the hospital mortality group were not included. The text states that 18 of the initial 95 survivors of aortic valve replacement died within the first two years following surgery-a 19 per cent mortality rate; the figure shows this percentage at three years. The control group used for comparison with the patients surviving aortic valve replacement was taken from a study completed 21 years before the completion of the aortic valve replacement study?. 5 Doctors Gehan and Freireich' have warned "Using patients from a previous study could be misleading if a relatively long interval had elapsed between studies [say, greater than three years), or if it could be demonstrated that important changes had taken place in clinical investigators, type of patients or therapy. Patients from a previous study should not be used as selected controls in such circumstances and a randomized prospective study is recommended. ,,1 Dr. Roberts and his associates compared their patient group co patients receiving no treatment, which is only one of the three alternate choices-no treatment, less drastic surgical therapy, or medical management. A comparison can be made between the total surgical group and a group of medically treated patients (Fig. 1)2 This is an admittedly poor comparison as no attempt can be made to compare the patients in the ~wo groups as to severity of disease, etiology of disease, age, sex. or other important factors affecting mortality. The two groups can only be compared in that the patients in both groups were symptomatic. Though imprecise, this comparison of surgically treated patients and medically treated patients is in accord with Dr. Selzer's editorial statement that valve replacement clearly prolongs life in the middle-aged or elderly patient with aortic stenosis who is symptomatic and whose symptoms are related to valve obstruction. 2 However, no such conclusion is obvious for patients with aortic insufficiency. It is assumed that the mortality of the surgically treated patients is evenly distributed as Dr. Roberts and his associates report: "Survival in the stenotic, regurgitant, and combined groups was nearly identical. ''~ This statement is in contrast to the data in their Fig. 4 representing the survival of these groups which presents significantly greater mortality for the patients with aortic regurgitation alone and in combination with aortic stenosis than the mortality presented for patients with aortic stenosis alone. The important question remains unanswered. For which patients does cardiac valve replacement affect the natural history of valvular heart disease in a positive way? The National Heart and Lung Institute has allocated 51 million dollars for clinical trials in 1976.7 It is imperative that the
537