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Published on: June 3, 2018
Effectiveness of a low contrast load CT angiography protocol in octogenarians and nonagenarians being evaluated for
Micheas Zemedkun1, Troy M LaBounty2, Geoffrey Bergman1
1Department of Medicine, NewYork-Presbyterian Hospital and the Weill Cornell Medical College, New York, NY, USA.
Insights
A low-dose contrast computed tomographic angiography (CTA) protocol is safe and feasible for elderly patients undergoing transcatheter aortic valve replacement (TAVR) screening. This method significantly reduces contrast load without compromising image quality or patient safety.
Area of Science:
- Cardiology
- Radiology
- Geriatrics
Background:
- Transcatheter aortic valve replacement (TAVR) screening necessitates computed tomographic angiography (CTA) for aortoiliofemoral assessment.
- Patients considered for TAVR often have pre-existing conditions increasing their risk of contrast-induced nephropathy (CIN).
- Standard CTA protocols involve a significant contrast volume, posing a risk to these vulnerable patients.
Purpose of the Study:
- To evaluate the feasibility and safety of a reduced contrast volume CTA protocol.
- To assess this protocol in octogenarians and nonagenarians at risk for CIN.
- To compare outcomes between standard and low-dose contrast CTA protocols.
Main Methods:
- A comparative study involving 54 elderly patients (≥80 years) undergoing CTA for TAVR screening.
- Patients were divided into two groups: standard contrast protocol (n=21) and low-dose contrast protocol (n=33).
- Evaluated parameters included contrast volume, CTA image quality and interpretability, CIN rates, and vascular complications.
Main Results:
- The low-dose contrast protocol used significantly less contrast volume (76±55 ml vs 127±18 ml, P<.001).
- Image quality (3.8±0.4 vs 3.9±0.3, P=.76) and interpretability (100% for both) were similar between groups.
- No significant difference in CIN rates was observed (3% vs 10%, P=.55), with no CIN events in the low-dose group; no major complications occurred.
Conclusions:
- A low-dose contrast CTA protocol is feasible and safe for screening elderly patients for TAVR.
- This protocol achieves a significant reduction in contrast load compared to standard protocols.
- The reduced contrast volume does not negatively impact image quality or patient safety outcomes.
Introduction:
Transcatheter aortic valve replacement (TAVR) typically requires computed tomographic angiography (CTA) for aortoiliofemoral assessment to determine feasibility of a transfemoral approach, although many candidates being considered for TAVR are at increased risk of contrast-induced nephropathy (CIN).
Objective:
To determine the feasibility and safety of a load contrast load CTA protocol in octogenarians and nonagenarians at risk of CIN.
Approach:
We evaluated 54 consecutive octogenarians and nonagenarians considered for TAVR who underwent CTA using a standard contrast protocol (n=21) versus a protocol incorporating low-dose contrast in patients at risk of CIN (n=33). We compared clinical characteristics, CTA image quality (score 1-4) and interpretability, and clinical outcomes, including CIN and vascular complications.
Results:
The mean age was 88.5±4.0 years, 37% were male, and chronic renal insufficiency was common in both the standard and low-dose contrast cohorts (57% vs. 70%, P=.39). The low-dose contrast protocol was associated with a significantly less contrast volume compared to standard contrast protocol (127±18 ml vs 76±55 ml, P<.001). Individuals imaged using low-dose (n=16) versus standard (n=17) contrast protocols received 80% less contrast volume (23±10 vs. 125±23 ml, P<.001). There was similar graded image quality (3.8±0.4 vs. 3.9±0.3, P=.76) and interpretability (100% for each, P=1.0) between standard and low-dose contrast protocol groups. There was no significant difference in rates of CIN after CTA between standard and low-dose contrast protocol groups (10% vs. 3%, P=.55), with no CIN events in those imaged by low-dose CTA. There were no major vascular injuries associated with TAVR or pigtail insertion, no major bleeding for CTA, and no noninterpretable studies in all patients.
Conclusion:
In this proof-of-principle study, a low-dose contrast protocol appears feasible and safe in octogenarians and nonagenarians undergoing screening for TAVR, and results in significant reduction in contrast load as compared to a standard contrast protocol without observed differences in image quality or safety.
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