Factors associated with symptom-to-surgery time in patients undergoing surgical repair for acute type A aortic dissection: an exploratory analysis from a prospective cohort study

Abstract

Objectives: The primary objective of this study was to investigate perioperative factors associated with symptom-to-surgery (STS) time in patients diagnosed with hyper-acute aortic dissection (AAD). The secondary objective was to develop a causal model to understand the relationship between STS times and hospital mortality in this population.

Design: Prospective cohort study.

Setting: Exploratory analysis of a national audit conducted by the Association of Cardiothoracic Anaesthesia and Critical Care.

Participants: From a total of 270 participants diagnosed with AAD with an STS time <72 hours, 218 were included in the multivariate analysis, after excluding 52 participants with missing covariates.

Main outcome measures: STS time, measured in hours. Hospital mortality at 30 days.

Results: In the multivariate analysis, mean STS time for misdiagnosed patients was nearly twice as high when compared with patients who initially had the correct diagnosis (estimated proportion of change=1.9, 95% CI 1.5 to 2.3, p<0.001). STS time decreased when patients were accompanied by a medical doctor in the ambulance transfer, had mean arterial blood pressure below 70 mm Hg or presented to the emergency department (ED) with a Glasgow Coma Scale (GCS) <15. Estimated ED-to-surgery (ETS) times were 1.8 hours longer for women than for men (10.5 hours, 95% CI 9.0 to 12.0 hours vs 8.7 hours, 95% CI 7.8 to 9.6 hours). From a total of 334 patients, 64 (19.2%) died. Mortality was higher in older patients and when STS time was ≥6 and <24 hours, compared with STS time <6 hours.

Conclusions: Potentially modifiable factors that may reduce STS times include avoidance of misdiagnosis and provision of a medical doctor for the ambulance transfer. Younger women had longer STS and ETS times, but further research is warranted to investigate the impact of age and sex on these times. The relationship between STS time and hospital mortality among these patients remains unclear.

Keywords: Women's health; cohort study; health care quality, access, and evaluation; health policy.

Figure 1. Flow chart illustrating patients included and excluded from this study for the analysis of the relationship between STS time ≤72 hours and mortality of patients diagnosed with AAD. AAD, type A acute aortic dissection; ETT, endotracheal tube placed on arrival to the operating room; MBP, mean blood pressure; STS, symptom-to-surgery time.

Figure 2. Histograms for the variable symptom-to-surgery time (given in hours) before and after logarithmic transformation, excluding patients undergoing surgery after 72 hours of symptoms onset.

Figure 3. Left: estimated symptom-to-surgery (STS) time according to age, obtained from the multivariate model described in table 4, without including an interaction between age and sex. The vertical lines represent the 95% CIs. Center: estimated STS times for women and men according to age, after including an interaction between age and sex (p=0.058). Right: estimated symptom-to-ED (STE) time and ED-to-surgery (ETS) time (dashed and dotted lines, respectively) for women and men according to age, after including an interaction between age and sex (p=0.284 and p=0.071, respectively). ED, emergency department.