Transcatheter aortic valve implantation (TAVI) without replacement requires precise knowledge of the anatomic dimensions and physical characteristics of the peripheral vasculature and aortic valve annulus at the insertion of the aortic valve leaflet and root at the level of the sinus of Valsalva. Multislice computed tomography (CT) allows detailed and precise assessment of the anatomic variables. Noncardiovascular structures are also amenable to assessment by CT. Of the 394 patients screened for TAVI, 259 (65.7%) had non-contrast CT to evaluate chest anatomy and contrast CT to evaluate ilio-femoral anatomy. Significant noncardiac findings were defined as those requiring immediate evaluation or intervention or additional clinical or radiologic follow-up. Noncardiovascular findings known before CT were not included. Of the 259 patients, 105 (40.5%) were men. The mean age was 82.3 ± 8.1 years. New, significant noncardiovascular findings were found in 89 (34.3%) and malignancy in 11 (4.2%) patients. Insignificant noncardiovascular findings were identified in 222 patients (85.7%). Signs of fluid retention were noted on CT in 105 patients (40.5%), with pleural effusion in 100 (38.6%), ascites in 17 (6.5%), and pericardial effusion in 14 (5.4%). Important peripheral vascular disease was found in 98 patients (37.8%), resulting in exclusion of 49 (19.1%) from TAVI using the transfemoral approach. An aortic aneurysm was found in 10 patients (3.8%) and a “porcelain” aorta (heavily calcified ascending aorta) in 19 (7.3%). In conclusion, malignancy and other noncardiovascular abnormalities are often found in patients who undergo CT for evaluation for TAVI. Populations must be meticulously examined to ensure that important findings are not missed.
Transcatheter aortic valve implantation (TAVI) has shown promise as an alternative to conventional open heart surgery for selected patients with severe symptomatic aortic stenosis. To be considered for TAVI for severe symptomatic aortic stenosis, candidates must have a contraindication to surgery or other characteristics that pose the risk of excess mortality or morbidity. Patient selection is crucial for TAVI success. The anatomic criteria must be met to facilitate valve delivery and placement. The major concern is injury to the femoral or iliac arteries during valve delivery. We currently screen patients for TAVI using noncontrast computed tomography (CT) of the chest and contrast CT of the abdomen and pelvis. As a byproduct, CT of the aortic valve and peripheral vasculature also yields findings involving noncardiovascular structures, such as the lungs, mediastinum, chest, and abdomen. The rate of incidental findings has recently been analyzed for unenhanced CT performed for coronary calcium screening and for contrast-enhanced CT in patients suspected of having coronary disease. The prevalence of unrecognized cancer and other noncardiovascular abnormalities has not been reported in a high-risk elderly population that is over-represented in TAVI trials. The aim of our study was to elucidate the prevalence of significant and insignificant noncardiovascular findings incidentally found on the images of high-risk elderly patients who had undergone CT for evaluation for TAVI.
Methods
We evaluated patients with severe symptomatic aortic stenosis with high-risk operative mortality >15% or a Society of Thoracic Surgeons score of ≥10 for TAVI. A total of 394 patients were evaluated from April 2007 to June 2009. All had undergone screening after echocardiography and diagnostic coronary angiography. Of these 394 patients, 259 (65.7%) had noncontrast CT of the chest and computed topographic angiography for the evaluation of iliofemoral anatomy. The other 135 patients did not undergo CT, because they were excluded on the basis of the echocardiography or catheterization results.
A novel technique has been developed in our center that uses only 10 to 15 ml of radiographic contrast for assessment of the peripheral vasculature. Minimum contrast use is very important in this high-risk elderly population. After diagnostic coronary angiography, a 4Fr or 5Fr pigtail catheter was left in situ, with its tip in the infrarenal abdominal aorta. The end of the pigtail catheter was connected to tubing containing heparinized saline under pressure and secured in place with an adhesive dressing. The patients were immediately transferred to the CT suite located near the cardiac catheterization laboratory. CT was performed with a 64- or 256-detector row cardiac system (Brilliance scanner, Philips, Eindhoven, The Netherlands). After the survey scan, a noncontrast helical computed tomographic scan of the chest, abdomen, and pelvis was acquired. The scan was used to assess for aortic calcification and to confirm the location of the pigtail catheter. When necessary, the catheter was repositioned such that the tip was in the infrarenal abdominal aorta. The power injector was connected to the pigtail catheter, and 10 to 15 ml of contrast (iopamidol, Isovue 370, Bracco Diagnostics, Princeton, New Jersey) mixed with normal saline in a 1:3 to 1:4 dilution was injected at 4 ml/s using a sterile technique through the pigtail catheter, during which time helical CT of the abdomen and pelvis was acquired (64/256 × 0.625 mm collimation, rotation time 0.75 second, pitch 0.64, 120 kV, 154 mA). Acquisition was performed during a 10- to 20-second breath hold. Immediately after acquisition, the pigtail catheter and femoral arterial sheath were removed. Computed tomographic image analyses were undertaken using commercially available software (Extended Brilliance Workspace, Philips, Best, The Netherlands). The contrast-enhanced images were assessed using axial images, multiplanar reformations, and 3-dimensional tools.
The examinations were reviewed prospectively by experienced computed tomographic radiologists. Significant noncardiac findings were defined as previously suggested by Horton et al as those that required immediate evaluation or intervention or those requiring additional clinical or radiologic follow-up. Noncardiac findings that were known before CT according to patient history and the medical records were not included in the present analysis.
Results
The study group consisted of 259 patients (40.5% men) who were screened with CT for TAVI. Their mean age was 82.3 ± 8.1 years. Their mean Society of Thoracic Surgeons score and mean logistic EuroSCORE was 11.7 ± 6.0 and 38.2 ± 22.1, respectively. A summary of their co-morbidities is listed in Table 1 . Significant noncardiovascular findings on CT were present for 89 patients (34.3%; Table 2 ). Malignancy confirmed by biopsy was found in 11 patients (4.2%). All patients with cancer identified by CT were excluded from the TAVI trial.
| Variable | Patients (n = 259) |
|---|---|
| Age (years) | 82.3 ± 8.1 |
| Men | 105 (40.5%) |
| Society of Thoracic Surgeons score (%) | 11.7 ± 6.0 |
| Standard EuroSCORE | 12.9 ± 3.2 |
| Logistic EuroSCORE | 38.2 ± 22.1 |
| Body surface area (m 2 ) | 1.7 ± 0.25 |
| Diabetes mellitus | 79 (30.5%) |
| Systemic hypertension | 229 (88.4%) |
| Hyperlipidemia ⁎ | 189 (72.9%) |
| Coronary artery disease † | 159 (61.4%) |
| Smoker | 54 (20.8%) |
| Chronic obstructive pulmonary disease | 78 (30.1%) |
| Renal failure ‡ | 109 (42.1%) |
| Previous stroke or transient ischemic event | 41 (15.8%) |
| Arrhythmia | 97 (37.4%) |
| Peripheral vascular disease | 97 (37.4%) |
| Previous coronary artery bypass grafting | 89 (34.3%) |
| Previous percutaneous coronary intervention | 40 (15.4%) |
| Ejection fraction (%) | 47.6 ± 20.4 |
| Aortic valve area (cm 2 ) | 0.78 ± 0.36 |
⁎ Included patients with previously documented diagnosis of hypercholesterolemia; patient could be treated with diet or medication; new diagnosis could have been made during this hospitalization with elevated total cholesterol >160 mg/dl.
† More than 50% stenosis in major coronary artery.
| Abnormality | n (%) |
|---|---|
| Overall significant abnormalities | 89 (34.3%) |
| Malignancy | 11 (4.2%) |
| Lung | 4 (1.5%) |
| Ovarian | 1 (0.38%) |
| Liver metastasis unknown primary | 1 (0.38%) |
| Pancreatic cancer | 1 (0.38%) |
| Lymphoma | 2 (0.77%) |
| Colon | 1 (0.38%) |
| Lymphangitic carcinomatosis | 1 (0.38%) |
| Nonmalignant significant abnormalities | |
| Noncalcified pulmonary nodules (mm) | |
| 4–10 | 11 (4.2%) |
| >10 | 9 (3.4%) |
| Hilar, mediastinal, or paratracheal lymphadenopathy >1 cm | 13 (5.01%) |
| Retroperitoneal or abdominal lymphadenopathy >1 cm | 2 (0.7%) |
| Thyroid nodule | 5 (1.9%) |
| Dense liver parenchyma (amiodarone liver) | 1 (0.38%) |
| Splenomegaly | 5 (1.9%) |
| Common bile duct dilation | 3 (1.1%) |
| Adrenal mass >1 cm (high density) | 7 (2.7%) |
| Ovarian cyst | 9 (5.8%) ⁎ |
| Hydronephrosis | |
| Severe | 1 (0.38%) |
| Moderate | 2 (0.77%) |
| Mild | 6 (2.3%) |
| Splenic infarct | 1 (0.38%) |
| Large hiatal hernia † | 1 (0.38%) |
| Extrapleural mass (pararenal soft tissue nodule) | 2 (0.77%) |
⁎ Percentage of female population.
† Stomach was in chest and adequate transesophageal echocardiography images could not be obtained during TAVI procedure.
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