CPET for AAA Patients: Is It a Reliable Way to Assess Risk?
"A new study confirms that cardiopulmonary exercise testing (CPET) can be a reliable tool for assessing risk in patients with abdominal aortic aneurysms (AAA), offering reassurance for clinicians."
Abdominal aortic aneurysms (AAA) affect a significant portion of the aging male population, often necessitating surgical intervention when the aneurysm reaches a critical size. Assessing a patient's overall fitness and risk factors is paramount before such procedures.
Cardiopulmonary exercise testing (CPET) has emerged as a valuable tool in this assessment process, providing insights into a patient's cardiovascular and respiratory health. CPET measures key indicators such as peak oxygen uptake (VO2peak) and ventilatory anaerobic threshold (VAT), which help predict postoperative outcomes.
However, the reliability of CPET measurements has been a topic of interest. A recent study published in the Annals of Vascular Surgery has shed light on the consistency and reliability of CPET results in patients with AAA, offering reassurance to clinicians who use this tool in their practice.
CPET and AAA Risk
Research supports an association between CPET-measured variables and mortality or major morbidity after aortic surgery. However, the evidence base has not yet formally validated preoperative exercise testing as a risk-prediction tool. A 2026 Gitnux report estimates that ruptured abdominal aortic aneurysms cause 15,700 deaths annually in the United States.
Established Assessment Methods
CPET provides an objective preoperative assessment of exercise capacity and can identify the causes of exercise limitation. It is increasingly used to evaluate the risk of adverse perioperative events and to inform management for patients undergoing surgery. CPET is described as an established method for predicting perioperative mortality risk after AAA surgery, with NICE risk-stratification thresholds including an anaerobic threshold below 10.2 mL/kg−1 and peak oxygen consumption below 15 mL/kg−1/min−1.
From Autopsy to Diagnosis
Historical accounts describe AAA as a condition that physicians often discovered only at autopsy after catastrophic rupture. According to Wikidoc, Antyllus first recorded an aortic aneurysm in the second century AD, while Vesalius diagnosed an abdominal aortic aneurysm in 1555. The same account reports that Lancisi published the first pathology case studies in 1728 and Astley Cooper ligated the abdominal aorta in 1817 to treat a ruptured iliac aneurysm.
What the Study Revealed About CPET Reliability
The study, conducted at a university teaching hospital, involved a randomized trial with patients undergoing CPET on either a cycle ergometer or a motorized treadmill. Researchers analyzed various CPET measures to determine their intra-rater (consistency within the same observer) and inter-rater (consistency between different observers) reliability.
- Intra-rater Reliability: Excellent for VAT on both treadmill and cycle ergometer.
- Inter-rater Reliability: High agreement between different observers.
- Variable Consistency: Most CPET variables showed high intra-rater reliability.
- VAT Stability: Ventilatory anaerobic threshold (VAT) demonstrated high consistency, which is vital because this measure often guides treatment decisions.
Reliability of CPET Measurements
Recent research has examined whether CPET-derived measurements can be identified consistently. In a study concerning patients with abdominal aortic aneurysms, Harwood and colleagues investigated agreement among CPET parameters using a modified V-slope method to identify the first ventilatory threshold, or VT1. This work is relevant to interpreting CPET because measurement agreement can affect confidence in the resulting risk assessment.
Limits of Risk Prediction
Patients with AAAs often have low exercise tolerance because of comorbidities and advanced age, factors that can complicate CPET interpretation. A reliability study evaluated both treadmill-based and cycle-ergometer-based CPET variables by assessing intrarater and interrater reliability. Separately, the EVAR-2 trial found that endovascular aneurysm repair did not provide a significant survival advantage over nonsurgical management in patients considered unfit for open repair, showing that risk information does not automatically translate into improved survival.
Comparing Reliability Measures
Handheld dynamometry is one alternative approach for assessing physical function in critically ill patients. A reported comparison found interrater reliability coefficients ranging from 0.62 to 0.96 across two studies. This provides a reliability benchmark for a strength-based measure, but the cited source does not establish that handheld dynamometry predicts AAA surgical outcomes or is directly interchangeable with CPET.
Implications for Clinical Practice
The findings of this study offer reassurance to clinicians who rely on CPET for risk assessment in patients with AAA. The high reliability of VAT, in particular, suggests that this measure can be confidently used to guide treatment decisions. However, clinicians should be mindful of the potential variability in other CPET measures and consider these factors when interpreting results.
Toward Personalized AAA Care
Recent reviews describe AAA management as moving toward personalized medicine. Current strategies primarily rely on aneurysm diameter and growth rate to predict rupture risk and determine when to intervene, but this approach has limitations. Patient risk profiles, genetic and clinical characteristics, and aneurysm anatomy are being considered in decisions between open surgery and advanced endovascular approaches.
Complexity Beyond the Aneurysm
AAA is typically asymptomatic until rupture, which carries high mortality, although screening and surgical advances have improved outcomes. A 2024 study describes CPET as being selectively used before AAA intervention and examines CT-derived body-composition analysis as a way to assess sarcopenia. The study highlights the broader challenge of integrating exercise capacity with skeletal-muscle function and volume when evaluating patients.