Categorising sub-massive pulmonary thromboembolism: No isolated role for shock index or its modified form (2019)

Type of publication:
Conference abstract

*Abdulsamad S.P.; *Crawford E.; *Makan A.; *Ahmad N.; *Srinivasan K.; *Moudgil H.

European Respiratory Journal; Sep 2019; vol. 54, PA1469

Background and Objectives: Managing sub-massive pulmonary thromboembolism (PTE) remains a therapeutic challenge and efforts have been made to sub-categorise continued risk based on clinical assessment and objective measures such as a raised serum lactate (>4 mmol/l) or abnormal Shock Index (Heart rate/systolic blood pressure, SIndex). The objective here was to investigate the SIndex and its modified form (MSIndex) to (1) report frequency of abnormal results in a population being investigated for PTE and (2) assess potential benefits in avoiding adverse outcome.
Method(s): Retrospective analysis of 1505 CT pulmonary angiograms undertaken over a 12 month period. Abnormal SIndex was taken as outside limits 0.5-0.9. MSindex was calculated conventionally as heart rate divided by (2xdiastolic blood pressure+systolic blood pressure)/3 and considered abnormal if <0.7 or >1.3. Analysis was on Excel.
Result(s): Mean age for the population was 67.7 (range 17-101) years. 337/1505 (22.4%) scans showed PTE and of this population 19 patients had adverse outcome either died within 3 months (7 had malignancy) or requiring Intensive Care during the admission. For patients without PTE (n=1168), the SIndex was abnormal in 334(28.6%) and the MSindex in 293 (25.1%). For patients with PTE (n=337), respectively these figures were 89 (26.4%) and 68 (20.2%). Of those with adverse outcomes, 13/19 Sindex and 17/19 MSIndex values were not abnormal.
Conclusion(s): Neither the SIndex not the MSIndex are discriminatory in helping distinguish the at risk groups with PTE and therefore cannot be used as an isolated criteria.