ABSTRACT
Several studies have linked calcification of the thoracic and lower extremity arterial trunks to an increased risk of developing coronary artery disease (CAD). Calcifications of the radial and/or ulnar artery are regularly identified in hand/wrist x-rays; however, the clinical relevance of these findings as related to identifying subclinical CAD is not well understood. Associations between CAD and upper extremity calcifications have been reported, but the timeline is unclear. The purpose of this study was to evaluate the association between upper extremity arterial calcifications on hand radiographs with CAD by coronary artery calcification (CAC) scoring in patients with no known history of CAD. This is a pilot single-center, prospective, matched cohort study. We included patients with no known history of CAD, related symptoms, or major risk factors. We recruited five patients with calcifications (cal+) and five patients matched by age, race, sex, and medical history but without calcifications (cal-). CAC scores were determined from computed tomography scanning, and lipid profile was evaluated. In the cal+ group, the mean CAC total score was 244.1; in the control (cal-) group, it was 85.2. The mean total cholesterol levels were 220.8 mg per dL and 167 mg per dL in the cal+ and cal- groups, respectively. Two cal+ patients with CAC scores of 937 and 669 died shortly after being enrolled in our study. Preliminary findings suggest that calcifications in the radial or ulnar artery in otherwise asymptomatic patients with no history of CAD may be an independent sign of CAD.
ABSTRACT
PURPOSE: Diagnosing acute tissue ischemia is challenging, particularly in patients with higher skin melanin content. We investigated whether near-infrared spectroscopy (NIRS) is effective and consistent in detecting upper extremity ischemia across various skin phenotypes. METHODS: Volunteers underwent tourniquet-induced upper extremity ischemia. Skin color was evaluated by the Fitzpatrick scale (FP, range: I-VI) and the Von Luschan scale (vL, range: 1-36). A NIRS probe was placed on one finger. The tourniquet was inflated to 250 mmHg and perfusion was restricted for 7 minutes, followed by a 10-minute monitored reperfusion period. The percent tissue oxygenation (StO2) was recorded. RESULTS: A total of 55 volunteers were enrolled (22 self-identified as Caucasian, 21 African American, 7 Asian, 2 Latinx, and 2 Biracial). Average starting and ending StO2 for the cohort was 72.2% and 45.9%, respectively. However, there was variability based on skin melanin content. Increasing vL correlated with lower starting StO2, smaller StO2 decrease, and shorter time to reach ischemic steady state. High skin melanin (FP scale IV-VI) was associated with significantly lower starting StO2 (-7.1%) and shorter time to reach ischemic steady state (-0.3 mins). African Americans had lower starting StO2 (-8.6%) and 7.8% lesser total StO2 decrease than other groups. CONCLUSIONS: NIRS can rapidly detect acute onset tissue ischemia in the upper extremity. However, given the lower starting StO2 and smaller total StO2 decrease after tourniquet-induced ischemia for patients with higher skin melanin, using NIRS for clinical detection of acute ischemia may be more challenging in these patients. These inconsistencies may limit use of NIRS clinically for spot identification of ischemia. CLINICAL RELEVANCE: Although NIRS has utility in tracking tissue oxygenation, variable performance with different skin melanin content raises concerns as to whether different cutoff/threshold levels are needed for different groups, and whether NIRS is reliable for spot checks in acute events.
