Clinical characteristics and BGA-optimized pretest probability of pulmonary embolism in the elderly.

Background: Pulmonary arterial embolism (PE) is not well characterized in elderly patients. In addition, unnecessary computed tomography pulmonary angiography (CTPA) examinations are often performed within this patient group, especially if the pretest probability is low.

Objective: To identify differences in clinical presentation in patients aged ≥80 years compared to patients <80 years and the effect of a BGA-optimized pretest probability to reduce unnecessary CTPAs according to age category.

Materials and methods: A retrospective analysis of patients with suspected PE and subsequent CTPA was performed, with evaluation of clinical data including capillary blood gas analysis (BGA) parameters (including standardized partial pressure of oxygen [sPaO₂]) over a 5-year period. Subsequently, the clinical characteristics of patients with confirmed PE were compared between the two age groups. In addition, an age-adjusted analysis of a BGA-optimized algorithm was performed in patients with a low pretest probability (PTP) according to the Wells score to reduce unnecessary CTPAs.

Results: PE was confirmed in 433 of 1538 patients with suspected PE, of which n = 98 (22.6%) were ≥ 80 years of age. Elderly patients with PE were less frequently male (p < 0.001), had lower rates of tachycardia (p = 0.021), but higher rates of cardiovascular disease history (p = 0.001) and oxygen administration at admission (p = 0.006) compared to those < 80 years. Signs of right heart dysfunction (p = 0.047) and elevated cardiac biomarkers (troponin: p < 0.001; nt-pro-BNP: p = 0.026) were also more common in the elderly. Additionally, simplified Pulmonary Embolism Severity Index (sPESI, p < 0.001) and in-hospital or 30-day death risk (p < 0.001) were higher in the elderly. Using a BGA-optimized algorithm with sPaO₂, unnecessary CTPA examinations were reduced by 33.2% in younger patients (75 of 226 without PE) and 23.5% in elderly patients (8 of 34 without PE).

Conclusions: Elderly patients with PE are characterized by higher clinical risk markers and elevated mortality rates compared to younger patients. In patients with suspected PE but low PTP, however, a significant number of unnecessary CTPAs could be avoided by using an BGA-optimized pretest algorithm in elderly patients.