The objective of this study is to define the repeatability and reproducibility of quantifying flow-mediated dilation (FMD) of the brachial artery (BA) using the AngioDefender (AD) methodology.

Repeatability will be assessed by repeat AD testing of the same subject 1 hour apart, using the same AD device and operator.

Reproducibility will be assessed by comparing FMD scores obtained for the same subject, but using different AD devices and operators.

Inclusion Criteria:

1. Men and women, ≥18 years old
2. Eastern Cooperative Oncology Group/Zubrod score performance status of 0, 1, or 2, determined within 7 days prior to FMD testing on Study Day 1 (Visit 1)
3. Written informed consent understood and signed; understanding of study procedures and ability to comply with them for the length of the study

Exclusion Criteria:

1. Body mass index (BMI) >50 kg/m2
2. Mid-upper arm circumference of arm selected for FMD testing <17 cm or >42 cm
3. Sinus arrhythmia, atrial fibrillation, atrial flutter, multifocal atrial tachycardia, frequent (>1 per 10-sec strip) premature atrial or ventricular contractions (isolated, non-isolated, or alternating), documented by 12-lead ECG with rhythm strip at the time of subject screening.
4. Clinical signs and/or symptoms of active viral or bacterial infections
5. Resting muscle tremor or inability to remain still for the duration of the testing period
6. Systolic blood pressure (SBP) at rest of >170 mmHg or diastolic blood pressure (DBP) at rest of ≥110 mmHg.
7. Diabetic subjects - Type I or II
8. Previous intolerable adverse reaction(s) to vascular testing using an upper extremity occlusive pneumatic cuff