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Should Asymptomatic Patients Discharged with Lower Hemoglobin Expect Worse Outcomes After Valve Surgery?
Niv Ad, MDSari D. Holmes, PhD
Alan M. Speir, MDGraciela Pritchard, BSLinda Halpin, MSN, RN
Inova Heart and Vascular InstituteFalls Church, VA
Disclosure Information
• Niv Ad, MD• AtriCure: consulting and speaker bureau• Medtronic: consulting and speaker bureau• Left Atrial Appendage Occlusion, LLC: co-owner
• Alan M. Speir, MD• Medtronic: Advisory board
Background
• Blood transfusion has been associated with increased morbidity and cost in cardiac surgery patients
• The decision to transfuse following cardiac surgery is often subjective and based primarily on low Hgb levels, age even in asymptomatic patients
Purpose
Study Purposes:
To determine whether asymptomatic patients discharged with lower Hgb levels are at increased risk for:
• Perioperative complications• Inferior quality of life • Increased 1-year mortality
Methodology
• Data collected prospectively on 1,107 valve-only procedures performed between 2008 and mid-2014
• Patients discharged alive with complete data (N =1,044) and divided into two groups:• Discharge Hgb levels ≤8 g/dL
(n=153)• Discharge Hgb levels >8 g/dL
(n=891)
Methodology
• Asymptomatic Patients: • Clinically stable • Ambulating well • Normal BP & no orthostatic
hypotension • No dizziness, tachycardia, tachypnea,
or shortness of breath
Methodology
• Multivariate analysis with Hgb as a continuous variable supplemented by a propensity score matching (PSM) conducted between Hgb groups (152 patient pairs after PSM)
Primary Research Questions
• Question 1: Does lower discharge Hgb level impact outcomes in the entire sample, adjusting for clinical factors with multivariate analyses?
• Question 2: After PSM based on discharge Hgb, do patients with discharge Hgb ≤8 g/dL have worse outcomes?
• Question 3: What is the role of blood product transfusion on outcomes?
Patient Characteristics Before PSM
CharacteristicHgb >8 g/dL
(n = 891)Hgb ≤8 g/dL
(n = 153) P
Age 62.0 ± 13.8 62.2 ± 15.1 0.924
Female 319 (36) 68 (44) 0.041
Ejection fraction (%) 57.7 ± 10.4 58.3 ± 9.6 0.507
CHF 260 (29) 68 (44) <0.001
Diabetes 132 (15) 43 (28) <0.001
Hypertension 527 (59) 104 (68) 0.039
PVD 51 (6) 13 (9) 0.187
Previous CVA 63 (7) 20 (13) 0.011
CPD 162 (18) 45 (29) 0.001
EuroSCORE II (%) 2.8 ± 4.9 6.0 ± 9.3 <0.001
Preop Hgb (g/dL) 13.1 ± 1.9 11.3 ± 1.8 <0.001
Elective status 793 (89) 119 (78) <0.001
Single valve procedure 802 (90) 116 (76) <0.001
CPB time (mins) 123 ± 44 135 ± 53 0.010
Results – Entire Sample
• Sample included:
• Mean age- 62.1 ± 14.0 Y and 37% female pts
• 918 single-valve,114 double-valve,12 triple-
valve
• MV (n =514), AV (n =593), TV (n =72), PV (n
=3)
• Mean Hgb at discharge = 9.9 ± 1.7 g/dL
Distribution of Discharge Hgb
Distribution of Discharge Hgb
STS-Defined Outcomes
OutcomeTotal Sample
(N = 1,044)
Prolonged ventilation (>24 hrs) 86 (8%)
Pneumonia 25 (2%)
Stroke/TIA 10 (1%)
Reoperation for bleeding 17 (2%)
Renal failure 12 (1%)
Readmissions <30 days 97 (9%)
Death <30 days 3 (0.3%)
Results – Entire Sample
• Multivariate analyses in entire sample, DC Hgb (continuous variable) not predictive of:
• Post discharge mortality <30 days (OR=1.04, P=0.916)
• Discharge to home (OR=1.07, P=0.435)
• Readmission <30 days (OR=0.92, P=0.307)
• One-year survival (HR=0.87, P=0.363)
Primary Research Questions
• Question 1: Does lower discharge Hgb level impact outcomes in the entire sample, adjusting for clinical factors with multivariate analyses?
• Question 2: After PSM based on discharge Hgb, do patients with discharge Hgb ≤8 g/dL have worse outcomes?
• Question 3: What is the role of blood product transfusion on outcomes?
Distribution of Propensity Scores
Distribution of Propensity Scores
Patient Characteristics by Group
CharacteristicUnmatchedHgb >8 g/dL
(n = 739)
MatchedHgb >8 g/dL
(n = 152)
MatchedHgb ≤8 g/dL
(n = 152)
Age 62.0 ± 13.8 62.1 ± 14.2 62.1 ± 15.1
Female *^ 249 (34) 70 (46) 68 (45)
Ejection fraction (%) 57.6 ± 10.6 58.2 ± 9.6 58.2 ± 9.7
CHF *^ 195 (26) 65 (43) 68 (45)
Diabetes *^ 92 (12) 40 (26) 43 (28)
Hypertension *^ 425 (58) 102 (67) 103 (68)
PVD * 36 (5) 15 (10) 13 (9)
Previous CVA *^ 46 (6) 17 (11) 19 (13)
CPD *^ 120 (16) 42 (28) 44 (29)
EuroSCORE II (%) *^ 2.5 ± 4.6 4.3 ± 6.0 6.0 ± 9.3
Preop Hgb (g/dL) *^ 13.4 ± 1.7 11.4 ± 2.0 11.3 ± 1.8
Elective status *^ 675 (91) 118 (78) 118 (78)
Single valve procedure *^ 682 (92) 120 (79) 116 (76)
CPB time (mins) *^ 121 ± 41 131 ± 53 134 ± 52
* Unmatched vs. Matched Hgb >8 g/dL groups (P < 0.05)^ Unmatched Hgb > 8 g/dL vs. Matched Hgb ≤8 g/dL groups (P <0.05)
Patient Characteristics by Group
CharacteristicUnmatchedHgb >8 g/dL
(n = 739)
MatchedHgb >8 g/dL
(n = 152)
MatchedHgb ≤8 g/dL
(n = 152)
Age 62.0 ± 13.8 62.1 ± 14.2 62.1 ± 15.1
Female *^ 249 (34) 70 (46) 68 (45)
Ejection fraction (%) 57.6 ± 10.6 58.2 ± 9.6 58.2 ± 9.7
CHF *^ 195 (26) 65 (43) 68 (45)
Diabetes *^ 92 (12) 40 (26) 43 (28)
Hypertension *^ 425 (58) 102 (67) 103 (68)
PVD * 36 (5) 15 (10) 13 (9)
Previous CVA *^ 46 (6) 17 (11) 19 (13)
CPD *^ 120 (16) 42 (28) 44 (29)
EuroSCORE II (%) *^ 2.5 ± 4.6 4.3 ± 6.0 6.0 ± 9.3
Preop Hgb (g/dL) *^ 13.4 ± 1.7 11.4 ± 2.0 11.3 ± 1.8
Elective status *^ 675 (91) 118 (78) 118 (78)
Single valve procedure *^ 682 (92) 120 (79) 116 (76)
CPB time (mins) *^ 121 ± 41 131 ± 53 134 ± 52
* Unmatched vs. Matched Hgb >8 g/dL groups (P < 0.05)^ Unmatched Hgb > 8 g/dL vs. Matched Hgb ≤8 g/dL groups (P <0.05)
Patient Characteristics After PSM
CharacteristicHgb >8 g/dL
(n = 152)Hgb ≤8 g/dL
(n = 152) P
Age 62.1 ± 14.2 62.1 ± 15.1 0.994
Female 70 (46) 68 (45) 0.818
Ejection fraction (%) 58.2 ± 9.6 58.2 ± 9.7 0.994
CHF 65 (43) 68 (45) 0.729
Diabetes 40 (26) 43 (28) 0.699
Hypertension 102 (67) 103 (68) 0.903
PVD 15 (10) 13 (9) 0.692
Previous CVA 17 (11) 19 (13) 0.723
CPD 42 (28) 44 (29) 0.799
EuroSCORE II (%) 4.3 ± 6.0 6.0 ± 9.3 0.063
Preop Hgb (g/dL) 11.4 ± 2.0 11.3 ± 1.8 0.651
Elective status 118 (78) 118 (78) >0.999
Single valve procedure 120 (79) 116 (76) 0.582
CPB time (mins) 131 ± 53 134 ± 52 0.680
Results – PSM Groups
• Matched Hgb ≤ 8 grp similar to Hgb > 8 grp on:
• Post-DC mortality <30 days (0% vs. 0.7%, P>0.999)
• Discharge to home (81% vs. 80%, P=0.667)
• Readmission <30 days (14% vs. 16%, P=0.522)
• One-year survival (89% vs. 91%, P=0.67)
Cumulative One-Year Survival
Months
Patients at Risk (95% CI)
Hgb ≤8 g/dL Hgb >8 g/dL
6 118 (0.91–0.98) 108 (0.90–0.98)
9 106 (0.88–0.97) 100 (0.89–0.98)
12 96 (0.84–0.95) 89 (0.86–0.97)
HRQL Improvement at 6 Months
Hgb > 8 g/dL
Hgb ≤ 8 g/dLP
HY
SIC
AL
CO
MP
OS
ITE
HR
QL
SC
OR
E
PRESURGERY 6 MONTHS
Physical (28% vs. 18% increase; P=0.268)Mental (7% vs. 6% increase; P=0.943)
Primary Research Questions
• Question 1: Does lower discharge Hgb level impact outcomes in the entire sample, adjusting for clinical factors with multivariate analyses?
• Question 2: After PSM based on discharge Hgb, do patients with discharge Hgb ≤8 g/dL have worse outcomes?
• Question 3: What is the role of blood product transfusion on outcomes?
Results – Blood Transfusion
• Multivariate analyses in entire sample found blood product transfusion (22%):
• Poorer 1-year survival (HR=2.27, P=0.036)
• Not related to readmissions (OR=1.51, P=0.244)
Results – Blood Transfusion
• In matched sample, pts with transfusions were (46%): • Similar in 30-day mortality (0.7% vs. 0%,
P=0.461)• Similar on readmissions (17% vs. 13%,
P=0.366)• Less likely to be discharged to home (69% vs.
89%, P<0.001)• Worse on 1-year cumulative survival (85.7%
vs. 94.8%, P=0.012) even after adjusting for discharge Hgb level (HR=3.00, P=0.021)
Summary
• In both multivariate and PSM analyses lower discharge Hgb in asymptomatic patients was not associated with increased post discharge complications and inferior survival
• Blood transfusion was associated with increased mortality at one year, however this was not the primary focus of the study
Conclusions
• We found that symptomatic patients with lower Hgb levels can be safely discharged following valve surgery without being transfused just to correct anemia.
• Based on our consistent experience in a busy center, it is imperative to change the culture around transfusion.
• Implementation of blood conservation protocols has been associated with improved outcomes and cost savings.
Inova Heart & Vascular InstituteCardiac Surgery Research
Research Team Members:• Niv Ad, MD• Rabia R. Ali, BS• Katherine Armstrong, BS• Jill C. Bennick• Hester Dean, BS• Linda Halpin, MSN, RN• Sari D. Holmes, PhD• Deborah Lamont, BSN, RN• Lisa M. Martin, PhD• Paul S. Massimiano, MD• Casey E. Miller, BS, CCRP• Graciela Pritchard, BS• Deborah J. Shuman, BS• Alan M. Speir, MD
Thank you!