CT pulmonary angiography in elderly patients: Outcomes in patients aged >85 years
Introduction
Pulmonary embolic disease is a common problem with 40,000 acute presentations (76 cases per 100,000 population) in England during the year 2010–2011.1 A number of diagnostic algorithms are available to stratify risk and guide further investigations.2, 3 Age remains an important independent predictor of risk4 and, therefore, the elderly population must be included in real-world management strategies. This will be cast further into focus with National Health Service (NHS) priorities shifting towards prevention and ambulatory care.5, 6, 7
Presently, the UK has 10 million people aged >65 years, which is projected to double over the next 50 years. The greatest rise will be in the most elderly patients with the number of individuals aged >85 years doubling to almost 3 million in the next 20 years.8 In the context of pulmonary embolic disease, the elderly provide a particular challenge: the differential diagnosis is often wide, common conditions often present atypically, and clinical, biochemical, and radiological tests are less accurate.9 Ventilation/perfusion radionuclide studies have higher inconclusive rates (approaching 60%,10) and D-dimer is of little utility.11 However, elderly patients can still benefit from treatment and long-term prophylaxis, albeit with higher rates of complications.4, 12 Therefore, accurate diagnosis of pulmonary emboli is essential in this high-risk group.
Computed tomography pulmonary angiography (CTPA) has been increasingly used as the diagnostic test of choice in the investigation of suspected pulmonary emboli, partly due to high published levels of accuracy,13, 14 but also due to the widespread emergency availability of CT in modern radiology departments. CTPA offers a single, fast, and accurate examination with the added advantages of diagnosis of alternative disease and stratification of risk if features such as right heart strain or massive clot burden are present.15, 16 The radiation burden has less lifetime biological effect in an elderly population,17 but the need for intravenous contrast media (IVCM) has attendant risks.
Radiographic contrast media have potential side effects including idiosyncratic anaphylactic reactions, and cardiotoxic and nephrotoxic effects.18 Contrast medium-induced nephropathy (CIN) has been variably categorized, but is commonly identified as a rise in serum creatinine within 2–5 days of the administration of IVCM.19, 20 CIN incidence varies according to route of administration, type of contrast medium, and patient factors, although increased age and decreased renal function are considered important risks.21, 22 CIN is an important cause of acute kidney injury, the latter is strongly associated with increased mortality and morbidity.23, 24 The safety of IVCM in very elderly patients is poorly defined. The present study attempts to assess the safety of IVCM administered during CTPA examinations in patients aged >85 years.
Section snippets
Patients
Institutional radiology picture archiving and communication system (PACS) databases covering three NHS acute hospitals were retrospectively searched using the examination code “CT angiogram pulmonary” and patients aged >85 years at the time of the examination were identified. Of over 750 patients identified in the study period (1 October 2006 to 31 October 2009), 140 patients with complete data were selected. Using radiology and pathology records, data were collected on age, gender, presence of
Results
One hundred and forty examinations were performed in 135 patients over the 3 year study period: 131 patients underwent a single CTPA. Three patients underwent two CTPA examinations and a single patient had three CTPA examinations (supplemental examinations performed 12–357 days after the initial CTPA). Ninety-eight were female (73%) with a mean age of 92 years (range 85–102 years). Ten patients (7%) had diabetes and eight patients (6%) were taking warfarin on admission. Baseline serum
Discussion
The present study demonstrates that CTPA is a safe and effective investigation in elderly patients with suspected pulmonary emboli. The overall positive rate of 16% is below that suggested by the British Thoracic Society,27 but compares with 19–23% found in large studies of younger patients.14, 28 Elderly patients with pulmonary emboli on CTPA demonstrated a trend towards improved outcomes: median survival was 16 months longer in patients with a pulmonary embolus (although this did not reach
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Coronary CT angiography in the elderly
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