Abstract

Abstract 4002

Poster Board III-938

Background

Multiple-detectors CTPA appears to have a higher sensitivity for PE as compared to single-detector CTPA. In particular, multiple-detectors CTPA allows better visualization of segmental and subsegmental pulmonary arteries, hence the proportion of patients with suspected PE in whom isolated subsegmental thrombus are reported might be higher using multiple-detectors CTPA.

The clinical significance of subsegmental PE is unknown. In the PIOPED study, PE limited to subsegmental pulmonary arteries were most prevalent among patients with low-probability ventilation/perfusion (V/Q) scans. Patients with non diagnostic (low or intermediate probability) V/Q scans can be safely managed without anticoagulation. Nonetheless, patients with isolated subsegmental PE detected on CTPA are more commonly receiving anticoagulation than not.

Purpose

To determine whether multiple-detectors CTPA increases the proportion of PE diagnosis limited to subsegmental arteries and to assess the safety of diagnostic strategies based on CTPA.

Data Source: A systematic literature search strategy was conducted using MEDLINE, EMBASE, the Cochrane Register of Controlled Trials and all EBM Reviews.

Study Selection

Twenty four articles met all the inclusions criteria (21 prospective cohort studies; 3 randomized controlled trials).

Data extraction

Two reviewers independently extracted data onto standardized forms.

Data Synthesis

A total of 2674 patients with suspected PE were included in the analyses. Of these, 1140 and 1534 patients underwent a single and multiple-detectors CTPA respectively.

Table 1

Weight-adjusted rates of sub-segmental pulmonary embolism diagnosis.

 SDCT All MDCT MDCT 4 detectors MDCT 16 detectors MDCT 64 detectors 
# of patients 1140 1534 461 207 100 
Proportion of SSPE (%, 95% CI) 4.6 (2.5-7.3) 9.4 (5.5-14.3) 7.1 (3.7-11.3) 6.9 (0.7-23.3) 15.0 (7-7-24.1) 
 SDCT All MDCT MDCT 4 detectors MDCT 16 detectors MDCT 64 detectors 
# of patients 1140 1534 461 207 100 
Proportion of SSPE (%, 95% CI) 4.6 (2.5-7.3) 9.4 (5.5-14.3) 7.1 (3.7-11.3) 6.9 (0.7-23.3) 15.0 (7-7-24.1) 

MDCT: Multiple-detectors computed tomographic pulmonary angiography; SDCT: single-detector computed tomographic pulmonary angiography; SSPE: subsegmental pulmonary embolism.

Table 2

Weight adjusted three-month VTE risk in patients with suspected pulmonary embolism and negative computed tomographic pulmonary angiography.

 SDCT All MDCT MDCT 4 detectors MDCT 16 detectors MDCT 64 detectors * 
# of patients 1943 2982 547 424 NA 
Rate of VTE on follow-up (%, 95% CI) 1.1 (0.5-1.7) 1.1 (0.7-1.6) 2.3 (1.1-3.7) 0.6 (0.1-1.6) NA 
 SDCT All MDCT MDCT 4 detectors MDCT 16 detectors MDCT 64 detectors * 
# of patients 1943 2982 547 424 NA 
Rate of VTE on follow-up (%, 95% CI) 1.1 (0.5-1.7) 1.1 (0.7-1.6) 2.3 (1.1-3.7) 0.6 (0.1-1.6) NA 

MDCT: Multiple-detectors computed tomographic pulmonary angiography; SDCT: single-detector computed tomographic pulmonary angiography.

Conclusion

The use of multiple-detectors CTPA in diagnostic strategies for PE appears to increase the proportion of patients diagnosed with subsegmental PE with comparable outcomes in patients with negative tests. This suggests that patients with subsegmental PE appear to not require anticoagulation.

Disclosures:

Rodger:Biomerieux: Research Funding; Boehringer Ingelheim: Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Pfizer: Research Funding; Leo Pharma: Research Funding; Bayer: Research Funding; GTC Therapeutics: Research Funding.

Author notes

*

Asterisk with author names denotes non-ASH members.