1. Identifying Low-Risk Patients with Pulmonary Embolism Suitable For Outpatient Treatment A VERITY Registry Pilot Study
N Scriven, T Farren, S Bacon, T Nokes, P Rose, R Arya, A McManus, A Nieland, D O’Shaughnessy

2. Five years later, outpatient treatment is not widely accepted, largely because no explicit clinical criteria exist to accurately identify low risk patients

3. Pulmonary Embolism Severity Index
Am J Respir Crit Care Med Vol 172. pp 1041–1046, 2005
Aujesky developed a clinical prediction rule that accurately classifies patients with PE into categories of increasing risk of mortality and other adverse medical outcomes
Based on logistic regression analysis, with 30-day mortality as the primary outcome, and patient demographic and clinical data at presentation as potential predictor variables

4. Points assigned to prognostic variables
Score is sum of patient’s age in years and the points for each variable

5. PESI risk classes Risk class Points Risk category Class I ≤65 very low
Class II low
Class III intermediate
Class IV high
Class V > very high

6. VERITY
A UK multi-centre observational VTE registry
Data collection for >5 years
>100,000 patient entries

7. Features of VERITY National registry – outpatient VTE treatment
Full spectrum of VTE – DVT and PE
Records information on patients presenting with suspected and confirmed VTE
Expanded data on demographics, presentation, management & outcomes
Extensive risk factor data

8. Study design
Pilot study - 4 VERITY hospitals participated to assess the accuracy of the PESI to predict 3-month mortality
Centres provided completed case report forms after retrospective review of patients’ notes on a total of 176 consecutive PE patients that had been in their care
The diagnosis had been confirmed by objective diagnostic testing
These patients do not represent an outpatient population, although some of these cases were treated as outpatients
Each patient was assigned as low (PESI risk classes I and II) or high-risk (risk classes III–V)
Each patient was assigned as low (PESI risk classes I and II) or high-risk (risk classes III–V)

9. Statistical plan
We calculated the sensitivity and specificity of the PESI
The accuracy of the index to classify patients was tested by receiver operating characteristic (ROC) curve analysis, plotted as 1–specificity versus sensitivity for 3-month all-cause mortality
The c statistic (area under the curve), representing the ability of the model to correctly classify patients, was estimated using the Wilcoxon non-parametric approach

10. Results Death at 3 months ROC analysis 0% in low-risk group
12.3% in high-risk group
Overall mortality at 3 months in all groups
4.5% (8/176)
ROC analysis
Sensitivity of PESI
1.0 (97.5% one-sided CI, 0.63 to 1)
Specificity of PESI
0.64 (95% CI, 0.56 to 0.71)

11. ROC curve – prediction of 3-month mortality
c statistic 0.90
95% CI –0.96

12. Very low risk PE (Aujesky score <65) 50 cases 3 cases 35yo female:
Number
Further VTE
Bleeding complication
Death
50 cases
3 cases
35yo female:
smoker; personal Hx; family Hx; leg paralysis
44yo female:
positive thrombophilia; recurrence at 4 months
53yo male:
post surgery; recurrence at 16 months
1 minor bleed
None
A case (2%) had a VTE within 3 months, who was a 35yo female, who smoked, had both personal and familial history of thrombosis and was a recent in patient and hence was immobile due to her surgery.

13. Low risk PE (Aujesky score 66-85) Number Further VTE
Bleeding complication
Death
61 cases
4 cases
61yo male:
Inpatient; smoker
58yo female
Ex-smoker; family Hx;
hormonal risk factor
67yo male
Ex-smoker; personal Hx
38yo female
Smoker; personal Hx; leg
paralysis
1 minor bleed
(occurred 9 – 17 months after diagnosis)
7.5% cases had a VTE within 3 months.
Deaths for low risk patients = 4 cases
51 yo male, died 17 mths after diagnosis
85 yo female, died 9 mths after diagnosis
81 yo female, had minor bleed, died 13 mths after diagnosis
70 yo male, died 12 mths after diagnosis

14. Intermediate risk PE (Aujesky score 86-105 pts) Number Further VTE
Bleeding complication
Death
29 cases
4 cases
57yo male:
Ex-smoker; ca prostate
67yo female:
Hormonal risk factor
48yo male:
Smoker; ca
83yo female
No risk factors
1 major bleed
5 cases
(between 2 weeks and 3 years)
12.5% cases had a VTE within 3 months

15. High risk PE (Aujesky score 106-125 pts) Number Further VTE
Bleeding complication
Death
22 cases
2 cases
74yo female:
Personal Hx
79yo male:
Ca prostate
3 cases
(between 1 week* and 2 years)
*metastatic ca lung
0 VTE, 0 bleeding events and 3 deaths, with one within 1/52 of admission due to metastatic lung cancer

16. (Aujesky score >125 pts)
Very high risk PE
(Aujesky score >125 pts)
Number
Further VTE
Bleeding complication
Death
14 cases
1 case
74yo female:
personal Hx
1 minor bleed
8 cases
(between 6 days and 2.5 yrs)
NB: One inpatient died due to a delayed diagnosis of PE (made on PM)
1 case (8% of very high risk group) had a VTE event within 3 months.

17. Discussion
There were no deaths in the low risk group at 3 months, although 4 deaths occurred at 9 – 17 months
The c statistic for the risk model (0.90) indicates a very good test for the likelihood of death
This pilot study suggests that the PESI accurately identifies PE patients at low risk of death
The findings were based on small group (n=176)
Outcome was limited to death at 3 months
There was a wide variation in the death rate between the 4 hospitals (ranging from 0% %)

18. VERITY PUSH
Prospective assessment will be undertaken by VERITY at centres moving to an outpatient (or short hospital stay) model for PE treatment.
A follow-up VERITY initiative - PUSH (Prospective follow Up Survey in VERITY Hospitals) was launched on 01/11/08
PUSH will run for a fixed 12-month timescale, with a six-month patient enrollment period and six-month follow-up
Major adverse outcomes (death, bleeding, recurrence) will allow accurate prospective assessment of PESI