S823 The Impact of a CT Angiography-Guided Protocol for Severe Lower Gastrointestinal Bleeding on Utilization and Outcomes

Introduction: Lower endoscopy for acute lower gastrointestinal bleeding (LGIB) generally has low therapeutic yield. Retrospective studies suggest that in patients with severe LGIB, CT angiography (CTA) can aid in bleeding localization and increase the therapeutic yield of interventional radiology (IR) or lower endoscopy. It is unknown if the uptake of CTAs can be increased and whether this can improve clinical outcomes. Thus, the primary aim of this study is to determine whether implementation of a multidisciplinary LGIB pathway can increase CTA utilization for severe LGIB. Secondary outcomes included rebleeding rates, readmission rates, and all-cause mortality. Methods: This longitudinal cohort study included patients who presented to the emergency room at New York Presbyterian Hospital with severe acute LGIB from 12/15/19 to 4/15/23. Eligible patients included those with bright red blood per rectum or maroon stools and hemodynamic instability on presentation with heart rate greater than 100 bpm or systolic blood pressure less than 100 mmHg. A multidisciplinary pathway involving the emergency department, gastroenterology, and IR was implemented to obtain early CTAs. Patients who met eligibility criteria on presentation underwent CTA and if positive IR guided intervention. If the CTA was negative or IR embolization was unsuccessful, patients underwent colonoscopy for further evaluation. Results were compared to a retrospective cohort of patients with severe LGIB over the four-year period prior to implementation of the CTA-guided pathway. Fischer’s exact test was performed to study factors associated with positive CTA. Results: Baseline and outcome data for both historical and intervention cohorts are shown in Table 1. Implementation of the CTA pathway increased CTA usage from 19/131 (14.5%) to 20/52 (38.5%) patients (P< 0.001). Of 41 total CTAs recorded, 12 were positive (29%). The Oakland score < 8 or hemoglobin >10 g/dL was associated with a negative CTA (P< 0.02). Overall, there were low rates of 30-day all-cause mortality (2.2%), bleeding-related mortality (1.1%), 30-day recurrent bleeding (4.4%), and 30-day readmission for GIB (2.2%), with no difference between the two groups. Conclusion: A multidisciplinary pathway more than doubled the percentage of CTAs performed for patients with severe LGIB. However, with an overall CTA positivity rate of 29%, there was no significant change in clinical outcomes such as rebleeding and mortality. Table 1. - Baseline and Outcome Characteristics Control Intervention Overall P-value (N=131) (N=52) (N=183) Baseline Characteristics Heart rate (HR) 0.0577 < = 100 20 (15.3%) 15 (28.8%) 35 (19.1%) > 100 111 (84.7%) 37 (71.2%) 148 (80.9%) Systolic blood pressure (BP) 0.121 < 100 31 (23.7%) 19 (36.5%) 50 (27.3%) >= 100 99 (75.6%) 33 (63.5%) 132 (72.1%) Missing 1 (0.8%) 0 (0%) 1 (0.5%) Age 0.394 Mean (SD) 58.95 (22.10) 62.00 (20.97) 59.82 (21.77) Median (Min, Max) 61.00 (20.00, 100.00) 67.50 (23.00, 94.00) 61.50 (20.00, 100.00) Missing 1 (0.8%) 0 (0%) 1 (0.5%) Sex 0.198 Female 60 (45.8%) 30 (57.7%) 90 (49.2%) Male 71 (54.2%) 22 (42.3%) 93 (50.8%) Syncope 0.337 No 83 (63.4%) 42 (80.8%) 125 (68.3%) Yes 10 (7.6%) 2 (3.8%) 12 (6.6%) Missing 38 (29.0%) 8 (15.4%) 46 (25.1%) Initial systolic BP (mmHg) 0.34 Mean (SD) 123.04 (24.69) 118.90 (30.19) 121.86 (26.36) Median (Min, Max) 122.50 (70.00, 179.00) 117.00 (53.00, 212.00) 122.00 (53.00, 212.00) Missing 1 (0.8%) 0 (0%) 1 (0.5%) Initial diastolic BP (mmHg) 0.33 Mean (SD) 77.09 (18.75) 74.13 (17.14) 76.21 (18.28) Median (Min, Max) 79.00 (37.00, 165.00) 72.00 (43.00, 119.00) 77.50 (37.00, 165.00) Missing 9 (6.9%) 0 (0%) 9 (4.9%) Initial HR (beats/min) 0.00769 Mean (SD) 109.75 (17.20) 102.21 (16.69) 107.61 (17.35) Median (Min, Max) 107.00 (64.00, 172.00) 105.00 (60.00, 150.00) 107.00 (60.00, 172.00) Initial hemoglobin (g/dL) 0.566 Mean (SD) 11.35 (3.66) 11.75 (5.24) 11.47 (4.16) Median (Min, Max) 11.90 (3.60, 33.00) 11.60 (4.80, 44.10) 11.70 (3.60, 44.10) Missing 3 (2.3%) 0 (0%) 3 (1.6%) Oakland score 0.882 Mean (SD) 17.78 (7.03) 17.60 (7.10) 17.72 (7.03) Median (Min, Max) 16.00 (5.00, 31.00) 15.00 (7.00, 32.00) 16.00 (5.00, 32.00) Missing 22 (16.8%) 2 (3.8%) 24 (13.1%) Intensive Care Unit stay 0.73 No 88 (67.2%) 35 (67.3%) 123 (67.2%) Yes 7 (5.3%) 4 (7.7%) 11 (6.0%) Missing 36 (27.5%) 13 (25.0%) 49 (26.8%) # of packed red blood cells transfused 0.0278 Mean (SD) 1.22 (1.77) 3.10 (5.48) 1.73 (3.28) Median (Min, Max) 1.00 (0.00, 8.00) 2.00 (0.00, 19.00) 1.00 (0.00, 19.00) Missing 77 (58.8%) 32 (61.5%) 109 (59.6%) Use of Aspirin 0.59 No 74 (56.5%) 34 (65.4%) 108 (59.0%) Yes 22 (16.8%) 7 (13.5%) 29 (15.8%) Missing 35 (26.7%) 11 (21.2%) 46 (25.1%) Use of Plavix 0.502 No 84 (64.1%) 39 (75.0%) 123 (67.2%) Yes 9 (6.9%) 2 (3.8%) 11 (6.0%) Missing 38 (29.0%) 11 (21.2%) 49 (26.8%) Use of novel oral anticoagulant 0.767 No 86 (65.6%) 36 (69.2%) 122 (66.7%) Yes 10 (7.6%) 5 (9.6%) 15 (8.2%) Missing 35 (26.7%) 11 (21.2%) 46 (25.1%) Use of Warfarin 0.666 No 89 (67.9%) 41 (78.8%) 130 (71.0%) Yes 5 (3.8%) 1 (1.9%) 6 (3.3%) Missing 37 (28.2%) 10 (19.2%) 47 (25.7%) Charlson Comorbidity Index 0.814 Mean (SD) 2.96 (2.55) 3.07 (2.86) 2.99 (2.64) Median (Min, Max) 3.00 (0.00, 9.00) 3.00 (0.00, 10.00) 3.00 (0.00, 10.00) Outcomes CTA ordered < 0.001 No 112 (85.5%) 32 (61.5%) 144 (78.7%) Yes 19 (14.5%) 20 (38.5%) 39 (21.3%) Deaths: within 30 days 0.116 No 66 (50.4%) 32 (61.5%) 98 (53.6%) Yes 1 (0.8%) 3 (5.8%) 4 (2.2%) Missing 64 (48.9%) 17 (32.7%) 81 (44.3%) Bleeding related death 1 No 63 (48.1%) 31 (59.6%) 94 (51.4%) Yes 1 (0.8%) 1 (1.9%) 2 (1.1%) Missing 67 (51.1%) 20 (38.5%) 87 (47.5%) Recurrent bleeding within 30 days 0.437 No 63 (48.1%) 30 (57.7%) 93 (50.8%) Yes 4 (3.1%) 4 (7.7%) 8 (4.4%) Missing 64 (48.9%) 18 (34.6%) 82 (44.8%) Readmission for GIB within 30 days 0.11 No 66 (50.4%) 31 (59.6%) 97 (53.0%) Yes 1 (0.8%) 3 (5.8%) 4 (2.2%) Missing 64 (48.9%) 18 (34.6%) 82 (44.8%) Thrombotic event within 30 days 0.111 No 65 (49.6%) 31 (59.6%) 96 (52.5%) Yes 0 (0%) 2 (3.8%) 2 (1.1%) Missing 66 (50.4%) 19 (36.5%) 85 (46.4%) Length of stay (days) 0.653 Mean (SD) 6.73 (40.33) 3.62 (9.44) 5.82 (34.23)