Clinical Radiology (1993) 48, 131 133

Are Routine Chest Radiographs Prior of Any Value?

to Angiography

D. J. GRIER, L. J. WATSON, G. G. HARTNELL* and P. WILDE

Department of Clinical Radiology and * University Department of Radiology, Bristol Royal Infirmary, Bristol

Chest radiographs are frequently requested prior to diagnostic angiography, though there is no published evidence of their clinical utility. This study was undertaken to evaluate their contribution to patient management.

The routine chest radiographs obtained prior to peripheral and coronary angiography in 240 patients were prospectively reviewed for abnormalities likely to affect management. Two hundred and twenty (91.7%) examinations were performed, of which 164 were obtained within 24 h of angiography. Previous radiographs were available in 154 patients (64.2 %). One hundred and sixteen radiographs were normal. There were 117 abnormalities on the radiographs of 104 patients, mainly cardiac enlargement and heart failure.

No angiogram was postponed or cancelled because of abnormalities detected on a routine radiograph, although radiographic findings led to a change in the volume of contrast medium injected into dilated aortic roots in 10 patients undergoing cardiac catheterization. Pre- angiography radiographs had no effect on the practice of peripheral angiography. In only one patient were further investigations and therapy instigated because of findings, but even in this case these findings were present on previous studies.

We conclude that routine pre-angiography chest radiographs are not necessary in the absence of specific clinical indications. Grier, D.J., Watson, L.J., Hartnell, G.G. & Wilde, P. (1993). Clinical Radiology 48, 131-133. Are Routine Chest Radiographs Prior to Angiography of Any Value?

Accepted for Publication 15 February 1993

Guidelines for the rational use of pre-operative chest radiography have been proposed [1]. Their implemen- tation has been shown to lead to a reduction in the number of pre-operative chest radiographs, with conse- quent savings in cost and unnecessary radiation exposure, and no evidence of increased morbidity or mortality [2]. Recently these guidelines have been re-emphasized, together with other strategies aimed at reducing radiation exposure to patients [3]. These include ensuring that an examination addresses a specific clinical question, opti- mizing the performance of each examination and improv- ing access to previous studies which may solve the clinical problem without further examination.

Chest radiographs are often routinely requested prior to diagnostic angiography in our hospital, despite pre- vious recent examinations being available. Their contri- bution to patient management during and after angiogra- phy has not been evaluated.

We felt that many of these examinations were unneces- sary. We have evaluated the utility of routine pre- angiography chest radiography in patients undergoing peripheral and coronary angiography.

PATIENTS AND METHOD

Two hundred and forty consecutive patients undergo- ing diagnostic angiography were prospectively recruited over a 4 month period. One hundred and ninety patients uhderwent coronary angiography and 50 peripheral

Correspondence to: Dr D. Grier, Department of Clinical Radiology, Bristol Royal Infirmary, Marlborough Street, Bristol BS2 8HW.

angiography. Patients whose angiograms were cancelled for non-medical reasons were not included in the study. For the purpose of this study a pre-angiography chest radiograph was defined as one requested specifically prior to the angiogram, and not for other stated diagnostic purposes. This radiograph was assessed for significant radiological abnormalities. The time interval between this film and angiography, the origin of the request and the availability of previous chest radiographs were docu- mented.

The influence of the chest radiograph on angiographic practice was determined by a questionnaire completed by the angiographer. The angiographer was asked whether the chest radiograph findings had led to an alteration in the volume of contrast medium used and if any abnor- malities on the chest radiograph were felt to warrant further investigation. Though low osmolar non-ionic contrast medium is used for all angiography in our hospital, the angiographers were also asked whether they would have ensured its use had they a choice.

The case notes of all patients were studied following the angiogram to identify any alteration to existing therapy, introduction of new treatment or further investigation resulting from findings on the pre-angiography chest radiograph.

RESULTS

Two hundred and forty patients were studied. The mean age was 61.3 years (range 34-87) and there were 162 male and 78 female patients. One hundred and ninety patients underwent coronary angiography (128 male and

132 CLINICAL RADIOLOGY

Table 1 - Availability of previous radiographs with interval prior to angiography

Angiogram Less than Between More than Total l month 1-12months I year

Routine pre-angiography Coronary 23 chest radiograph obtained Peripheral 1

No pre-angiography chest Coronary 5 radiograph Peripheral 0

75 26 124 I0 5 16

I 0 6 3 5 8

Total 29 89 36 154

Table 2 - Abnormal findings (117) on pre-angiography radiographs of 104 patients

CAzR finding Coronary Peripheral

Cardiomegaly 55 4 Valyular disease 28 0 Cardiac failure 20 2 Thoracotomy 1 0 Thoracic aortic aneurysm 1 0 Upper lobe fibrosis 1 0 Basal collapse I* 0 Consolidation 1 * 0 Pleural calcification 0 1 Pleural effusion 0 I Pulmonary nodule 0 1

Total 108 9

* Not present on previous radiograph.

62 female; mean age 59.3 years) and 50 patients under- went peripheral angiography (34 male and 16 female; mean age 68.2 years).

Pre-angiography chest radiographs were obtained in 220 patients (91.7%). These were in 185/190 patients undergoing coronary angiography (97.4%) and 35/50 undergoing peripheral angiography (70%). A single frontal radiograph was obtained in 89 patients. A frontal and lateral film was taken in 81 patients, and 50 patients had standard and penetrated frontal radiographs and a lateral film. Patients having three films were referred from the cardiology department and the majority of these (47/50) had had no previous chest radiographs in our department. The remainder were either cardiac patients with previous films or patients referred from other clinicians.

Two hundred and four requests for chest radiography (92.7%) originated from the ward to which the patient had been admitted prior to angiography, and 16 were referred from the out-patient department. One hundred and sixty-four examinations were obtained within 24 h of angiography. Of the remaining 56 chest radiographs, 36 were requested 2-7 days, five between 1-4 weeks, and 15 over 1 month before angiography.

Only 14 requests provided useful, relevant clinical information justifying the need for chest radiography in its own right; indications for the remainder were given as 'pre-cardiac catheter', 'pre-angiography' or 'routine for catheter'.

Previous chest radiographs were available at the time of angiography in 154 patients (64.2%) (Table I). One hundred and forty of these patients had a pre-angiogra- phy chest radiograph. Previous examinations were avail- able for 14 of the 20 patients not having a pre-angiogra- phy chest radiograph.

Pre-angiography chest radiographs were normal in 116 patients (52.7%). Ninety (77.6"/0) of these patients under-

went coronary angiography and 26 (22.4%) peripheral angiography. One hundred and seventeen abnormalities were detected on pre-angiography radiographs in 104 patients (Table 2).

No angiogram was postponed or cancelled because of findings on a pre-angiography chest radiograph. Review of the questionnaires completed by the angiographer showed that pre-angiography chest radiographs had no effect on the practice of peripheral angiography. The performance of coronary angiography was altered in 10 patients. A reduced volume of contrast medium was used in nine patients with a dilated aortic root due to aortic valve disease, and a larger volume was used for the same reason in another patient.

Chest radiographs could potentially have altered prac- tice in a further 15 patients undergoing coronary angio- graphy in whom the angiographer might have ensured the use of non-ionic contrast medium because of cardiome- galy or heart failure. However, in this hospital non-ionic contrast media are used for all angiography and so no change in practice actually occurred.

In only one patient, with a calcified aneurysm of the ascending aorta, were further investigations carried out leading to the diagnosis of syphilis and appropriate treatment. However, this finding had been present on previous chest radiographs and was also apparent at coronary angiography.

A further patient had unexpected radiographic findings of basal pulmonary collapse/consolidation. Examination of the case notes showed that no further investigations or treatment were instigated.

DISCUSSION

This study has shown that a chest radiograph is obtained shortly before angiography in most patients (91.7%). This is despite previous chest radiographs being available in almost two thirds of cases. In no case did findings on a pre-angiography chest radiograph lead to the postponement or cancellation of the angiogram. In approximately half of the patients undergoing coronary angiography, and a greater proportion of those who underwent peripheral angiography, the radiograph was normal. In a large number of the remainder, most of the findings could have been predicted from clinical, previous radiographic and echocardiographic findings.

The reported alteration in the volume of contrast medium injected into a dilated aortic root during coron- ary angiography occurred in a small proportion (5%) of patients. The radiographic findings were present on previous radiographs and also visible at fluoroscopy during catheter manipulation. Although the actual effect of the pre-angiography radiograph is difficult to gauge, it was probably minimal. The perceived need to reduce the

CHEST RADIOGRAPHY PRIOR TO ANGIOGRAPHY 133

volume of contrast medium in these patients is also difficult to justify.

Although further investigations leading to the diagno- sis of syphilis were instituted in one patient because of a calcified aneurysm of the ascending aorta, these radio- graphic findings were not new.

Pre-operative chest radiography has been evaluated by the Royal College of Radiologists and has been found to be unhelpful, except in certain defined circumstances. These include patients with acute respiratory symptoms, possible metastases, suspected or established cardio- respiratory disease with no CXR within 12 months and recent immigrants from areas where tuberculosis is endemic [1,2]. The value of routine chest radiography in other clinical situations has only been sporadically addressed in the literature. It has been found to be unnecessary in patients undergoing biliary lithotripsy [4], and prior to elective gynaecological operations for non- malignant conditions [5]. Its frequent use has also been questioned in the management of patients with chronic obstructive airways disease [6].

Even those who would defend the use of routine pre- operative chest radiography concede that as a screening test it has no value, but that in a small number of patients (less than 10%) it may be useful as a baseline radiograph to use for comparison with post-operative studies [7].

It has been suggested in a recent review that routine chest radiography in patients admitted to hospital with no cardiorespiratory history may reveal findings which are more often misleading than helpful [8]. As a result the authors state that chest radiographs should no longer be obtained on patients admitted to hospital or in pre- operative patients unless criteria similar to the guidelines of the Royal College of Radiologists on pre-operative chest radiographs are met.

Chest radiography is the most common radiographic examination performed in the U K (approximately 9 000 000 per annum) and thus represents an important source of exposure of ionizing radiation to the population [9]. It has been estimated that the lifetime risk for the induction of a fatal cancer from chest radiography is

between 0.7 and 2.0 per million patient examinations [3]. Any strategy which might lead to a more rational use of this investigation could therefore have an important effect in reducing the radiation burden to the population. The financial savings are also potentially large.

All investigations utilizing ionizing radiation should be justified by showing that likely benefit exceeds any risk to the patient. On the basis of this study routine pre- angiography chest radiography cannot be recommended: it is of no relevance to the diagnostic procedure, and should only be performed if there are additional clinical indications that would justify radiography in their own right.

REFERENCES

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2 Roberts CJ, Fowkes FGR, Ennis WP, Mitchell M. Possible impact of audit on chest x-ray requests from surgical wards. Lancet 1983;II:446 448.

3 Report by the Royal College of Radiologists and the National Radiological Protection Board. Patient dose reduction in diagnotic radiology. Documents o f the National Radiological Protection Board 1990;1(3):9-13.

4 Malone DE, Becker CD, Muller NL, Burhenne HJ. Is routine chest radiography required with biliary lithotripsy? American Journal o f Roentgenology 1989;152:987-989.

5 Umbach GE, Zubek S, Deck H J, Buhl R, Bender HG, Jungblutt RM. The value of pre-operative chest x-rays in gynaecological patients. Archives of Gynaecology and Obstetrics 1988;243:179-185.

6 Sherman S, Skoney JA, Ravikrishnan KP. Routine chest radiographs in exacerbations of chronic obstructive pulmonary disease. Archives of Internal Medicine 1989; 149:2493-2496.

7 Mendelson DS, Khilnani N, Wagner LD, Rabinowitz JG. Pre- operative chest radiography; value as a baseline examination for comparison. Radiology 1987;165:341-343.

8 Tape TG, Muschlin AI. The utility of routine chest radiographs. Annals of lnternal Medicine 1986;104:663-670.

9 Kendall GM, Darby SC, Harries SV, Rae S. A frequency survey of radiological examinations carried out in National Health Service hospitals in Great Britain in 1977 for diagnostic purposes. National Radiological Protection Board Report 1980; R104 HMSO, London.