Does Moderate Hypothermia Really Carry Less Bleeding Risk than Deep Hypothermia For Circulatory Arrest? A Propensity-Matched Comparison in Hemiarch Replacement.

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Presentation transcript:

Does Moderate Hypothermia Really Carry Less Bleeding Risk than Deep Hypothermia For Circulatory Arrest? A Propensity-Matched Comparison in Hemiarch Replacement Jeffrey E. Keenan, MD; Hanghang Wang, MD; Brian C. Gulack, MD; Asvin M. Ganapathi, MD; Nicholas D. Andersen MD; Brian R. Englum, MD; Yamini Krishnamurthy, MSIV; Jerrold H. Levy, MD; Ian J. Welsby, MD; G. Chad Hughes, MD American Association for Thoracic Surgery Annual Meeting April 28, 2015 Seattle, WA

The authors have no conflicts of interest to report. Disclosures The authors have no conflicts of interest to report. The authors have no conflicts of interest to report.

Background Controversy exists over the optimal degree of hypothermia during surgery of aortic arch with circulatory arrest

Background Controversy exists over the optimal degree of hypothermia during surgery of aortic arch with circulatory arrest Deep Hypothermia Moderate Hypothermia Greater suppression of metabolic activity May offer better organ protection, particularly for the brain and spinal cord which are highly susceptible to hypoxic injury May provide adequate visceral and cerebral protection in conjunction with regional perfusion to the brain during systemic arrest Potentially mitigates hypothermia-related complications Vs.

Coagulopathic bleeding during aortic arch surgery Background Coagulopathic bleeding during aortic arch surgery Multifactorial Hypothermia-related platelet dysfunction Coagulation factor consumption during prolonged CPB Theoretically, milder degrees of hypothermia may reduce coagulopathy and bleeding-related complications Lack of empirical data to support this claim

Objective To determine whether moderate hypothermic circulatory arrest (MHCA) compared to deep hypothermic circulatory arrest (DHCA) reduced the risk of bleeding and the blood product transfusion in patients undergoing aortic hemiarch replacement.

Duke University Medical Center Aortic Surgery Database Methods Duke University Medical Center Aortic Surgery Database Prospectively maintained Contains >1500 procedures from 2005-present. Study population Patients who underwent replacement of aortic root or supracoronary ascending aneurysm (+/- valve) with concomitant hemiarch replacement from 7/2005 to 8/2014.

Methods Aortic Hemiarch Replacement Deep HCA Moderate HCA Minimum Systemic Temperature ≤ 20°C Moderate HCA Minimum Systemic Temperature > 20°C

Methods Aortic Hemiarch Replacement Deep HCA Moderate HCA Minimum Systemic Temperature ≤ 20°C Moderate HCA Minimum Systemic Temperature > 20°C 1:1 Propensity Match age, gender, race, BMI, hypertension, tobacco use, diabetes, coronary artery disease, congestive heart failure, history of stroke, chronic renal insufficiency (baseline creatinine >1.5), connective tissue disease, ASA class, bicuspid aortic valve, acute type A aortic dissection, chronic type A aortic dissection, preoperative malperfusion or shock, aortic rupture, procedural status, concomitant root replacement, redo sternotomy, and preoperative hematologic labs

Methods Aortic Hemiarch Replacement Deep HCA Moderate HCA Minimum Systemic Temperature ≤ 20°C Moderate HCA Minimum Systemic Temperature > 20°C Propensity Match Study Outcomes Primary (bleeding-related): operative day transfusion, reoperation for bleeding, cell saver transfusion, rFVIIa utilization, 12 hour postoperative chest tube output, post-op labs Secondary: mortality, organ-specific morbidity, intraoperative outcomes

Aortic Hemiarch Replacement Results Aortic Hemiarch Replacement N=571 Deep HCA N=401 (70.2%) Min. Sys. Temp.= 17.1°C Moderate HCA N=170 (29.8%) Min. Sys. Temp.= 24.0°C

Results: Frequency of DHCA and MHCA

Aortic Hemiarch Replacement Methods Aortic Hemiarch Replacement Deep HCA N=401 Min. Sys. Temp.= 17.1°C Moderate HCA N=170 Min. Sys. Temp.= 24.0°C Propensity Matching Deep HCA N=155 Min. Sys. Temp.= 17.0°C Moderate HCA N=155 Min. Sys. Temp.= 24.0°C

Results: Matched Baseline Characteristics Variable Deep HCA (N=155) Moderate HCA P-value Age 60 (47, 69) 58 (51.5, 68) 0.82 Female 50 (32.3%) 49 (31.6%) 0.99 White Race 108 (69.7%) 114 (73.5%) 0.53 Body Mass Index 28.4 (25.0, 31.8) 28.4 (25.3, 32.3) 0.66 Hypertension 124 (80.0%) 123 (79.4%) Hyperlipidemia 78 (50.3%) 86 (55.5%) 0.43 Smoker 62 (40.0%) 55 (35.5%) 0.48 Diabetes 12 (7.7%) 13 (8.4%) Coronary Artery Disease 38 (24.5%) History of MI 10 (6.5%) 16 (10.3%) 0.31 CHF (NYHA ≥2) 52 (33.5%) 43 (27.7%) 0.32 History of Stroke/TIA 11 (7.1%) COPD 17 (11.0%) 0.57 Chronic Kidney Disease 24 (15.5%) 23 (14.8%) Peripheral Artery Disease 6 (3.9%)

Results: Matched Aortic Characteristics Variable Deep HCA (N=155) Moderate HCA P-value Connective Tissue Disease 4 (2.6%) 5 (3.2%) 0.99 Bicuspid Aortic Valve 58 (37.4%) 56 (36.1%) 0.91 Ascending Aortic Dissection 45 (29.0%) 48 (31.0%) 0.80 Acute 35 (77.8%) 42 (87.5%) 0.28 Chronic 10 (22.2%) 7 (14.6%) 0.42 Acute Dissection with Malperfusion or Shock 10 (6.5%) 12 (7.7%) 0.83 Max Aortic Diameter 5.4 (5.0, 5.8) 5.3 (5.0, 5.8) 0.53 Aortic Rupture 8 (5.2%) 9 (5.8%)

Results: Matched Procedural Characteristics Variable Deep HCA (N=155) Moderate HCA P-value ASA class 0.28 2 18 (11.6%) 27 (17.4%) 3 94 (60.6%) 83 (53.5%) 4 43 (27.7%) 45 (29.0%) Procedural Status 0.45 Elective 111 (71.6%) 104 (67.1%) Urgent 16 (10.3%) 14 (9.0%) Emergent 28 (18.1%) 37 (23.9%) Previous Aortic Surgery 25 (16.1%) 22 (14.2%) 0.75 Redo Sternotomy 0.76 Root Replacement 49 (31.6%) 0.99

Results: Preoperative Hematologic Labs Variable Deep HCA (N=155) Moderate HCA P-value Hemoglobin (g/dL) 13.3 (11.9, 14.7) 13.5 (12.1, 14.7) 0.28 INR 1.0 (1.0, 1.1) 0.47 Platelets (109/L) 204 (170.5, 249) 197 (165, 242) 0.26 PTT 30.1 (27.8, 32.7) 30.5 (28.0, 32.7) 0.70 Creatinine 1.0 (0.9, 1.2) 0.58

Results: Bleeding-Related Outcomes Deep HCA (N=155) Moderate HCA P-value Operative Day Transfusion PRBC (units) 2 (0, 4) 0.86 Plasma (units) 6 (4, 8) 4 (4, 8) 0.1 Platelets (units) 2 (1, 3) 2 (1.5, 3) 0.45 Cryoprecipitate (units) 0 (0, 1) 0.02 ≥1 unit Cryoprecipitate 60 (36.1%) 70 (44.5%) 0.003 Cell Saver (mL) 500 (250, 744) 472 (250, 700) < 0.001 Intraoperative rFVIIa 35 (22.6%) 52 (33.5%) 0.04 Postoperative rFVIIa 8 (5.2%) 5 (3.2%) 0.57 12hr Chest Tube Output (mL) 405 (262, 740) 360 (230, 633) Reoperation for Bleeding 1

Results: Bleeding-Related Outcomes Deep HCA (N=155) Moderate HCA P-value Operative Day Transfusion PRBC (units) 2 (0, 4) 0.86 Plasma (units) 6 (4, 8) 4 (4, 8) 0.1 Platelets (units) 2 (1, 3) 2 (1.5, 3) 0.45 Cryoprecipitate (units) 0 (0, 1) 0.02 ≥1 unit Cryoprecipitate 60 (36.1%) 70 (44.5%) 0.003 Cell Saver (mL) 500 (250, 744) 472 (250, 700) < 0.001 Intraoperative rFVIIa 35 (22.6%) 52 (33.5%) 0.04 Postoperative rFVIIa 8 (5.2%) 5 (3.2%) 0.57 12hr Chest Tube Output (mL) 405 (262, 740) 360 (230, 633) Reoperation for Bleeding 1

Results: Bleeding-Related Outcomes Deep HCA (N=155) Moderate HCA P-value Operative Day Transfusion PRBC (units) 2 (0, 4) 0.86 Plasma (units) 6 (4, 8) 4 (4, 8) 0.10 Platelets (units) 2 (1, 3) 2 (1.5, 3) 0.45 Cryoprecipitate (units) 0 (0, 1) 0.02 ≥1 unit Cryoprecipitate 60 (36.1%) 70 (44.5%) 0.003 Cell Saver (mL) 500 (250, 744) 472 (250, 700) < 0.001 Intraoperative rFVIIa 35 (22.6%) 52 (33.5%) 0.04 Postoperative rFVIIa 8 (5.2%) 5 (3.2%) 0.57 12hr Chest Tube Output (mL) 405 (262, 740) 360 (230, 633) Reoperation for Bleeding 1

Results: Bleeding-Related Outcomes Deep HCA (N=155) Moderate HCA P-value Operative Day Transfusion PRBC (units) 2 (0, 4) 0.86 Plasma (units) 6 (4, 8) 4 (4, 8) 0.1 Platelets (units) 2 (1, 3) 2 (1.5, 3) 0.45 Cryoprecipitate (units) 0 (0, 1) 0.02 ≥1 unit Cryoprecipitate 60 (36.1%) 70 (44.5%) 0.003 Cell Saver (mL) 500 (250, 744) 472 (250, 700) < 0.001 Intraoperative rFVIIa 35 (22.6%) 52 (33.5%) 0.04 Postoperative rFVIIa 8 (5.2%) 5 (3.2%) 0.57 12hr Chest Tube Output (mL) 405 (262, 740) 360 (230, 633) Reoperation for Bleeding 1 A total of 50,010 patients received a lobectomy during the study period of which 3.9% were found to have positive margins following surgery. Patients with positive margins were more likely to be male (CLICK) and black (CLICK) than patients with negative margins. They were also less likely to be treated at an academic center (CLICK).

Results: Bleeding-Related Outcomes Deep HCA (N=155) Moderate HCA P-value Operative Day Transfusion PRBC (units) 2 (0, 4) 0.86 Plasma (units) 6 (4, 8) 4 (4, 8) 0.1 Platelets (units) 2 (1, 3) 2 (1.5, 3) 0.45 Cryoprecipitate (units) 0 (0, 1) 0.02 ≥1 unit Cryoprecipitate 60 (36.1%) 70 (44.5%) 0.003 Cell Saver (mL) 500 (250, 744) 472 (250, 700) < 0.001 Intraoperative rFVIIa 35 (22.6%) 52 (33.5%) 0.04 Postoperative rFVIIa 8 (5.2%) 5 (3.2%) 0.57 12hr Chest Tube Output (mL) 405 (262, 740) 360 (230, 633) Reoperation for Bleeding 1

Results: Bleeding-Related Outcomes Deep HCA (N=155) Moderate HCA P-value Operative Day Transfusion PRBC (units) 2 (0, 4) 0.86 Plasma (units) 6 (4, 8) 4 (4, 8) 0.1 Platelets (units) 2 (1, 3) 2 (1.5, 3) 0.45 Cryoprecipitate (units) 0 (0, 1) 0.02 ≥1 unit Cryoprecipitate 60 (36.1%) 70 (44.5%) 0.003 Cell Saver (mL) 500 (250, 744) 472 (250, 700) < 0.001 Intraoperative rFVIIa 35 (22.6%) 52 (33.5%) 0.04 Postoperative rFVIIa 8 (5.2%) 5 (3.2%) 0.57 12hr Chest Tube Output (mL) 405 (262, 740) 360 (230, 633) Reoperation for Bleeding 1

Results: Bleeding-Related Outcomes Deep HCA (N=155) Moderate HCA P-value Hemoglobin (g/dL) 9.9 (9.25, 10.5) 10.0 (9.4, 10.55) 0.23 Platelets (109/L) 140 (115, 176.5) 147 (127, 173) 0.08 INR 1.1 (1.0, 1.2) 1.1 (0.9, 1.2) 0.03 INR ≥ 1.2 72 (46.8%) 53 (35.6%) 0.048 PTT (sec) 28.7 (25.95, 37.0) 28.6 (21.3, 31.4) 0.26

Results: Secondary Outcomes - Intraoperative Variable Deep HCA (N=155) Moderate HCA P-value Cardiopulmonary Bypass Time 204 (182, 232) 182 (150, 215) < 0.001 Crossclamp Time 126 (107, 154) 117 (95, 147) 0.07 Circulatory Arrest Time 17 (15, 22) 16.5 (13, 20) 0.04 Operative Time 329 (297, 378) 320 (281, 367) 0.27

Results: Secondary Outcomes - Intraoperative Variable Deep HCA (N=155) Moderate HCA P-value Cardiopulmonary Bypass Time 204 (182, 232) 182 (150, 215) < 0.001 Crossclamp Time 127 (107, 154) 117 (95, 147) 0.07 Circulatory Arrest Time 17 (15, 22) 16.5 (13, 20) 0.04 Operative Time 329 (297, 378) 320 (281, 367) 0.27

Results: Secondary Outcomes - Clinical Deep HCA (N=155) Moderate HCA P-value 30-Day/Inpatient Mortality 3 (1.9%) 5 (3.2%) 0.72 AKI ( Creatinine > 2.0 & 2x baseline) 11 (7.1%) 16 (10.3%) 0.42 New Onset Dialysis 1 (0.6%) 7 (4.5%) 0.07 Stroke 2 (1.3%) 0.99 Transient Ischemic Attack Paraparesis Paraplegia Prolonged Ventilation (>24 hours) 19 (12.3%) 13 (8.4%) 0.35 30-Day Readmission 20 (12.9%) 0.60 Discharge to location other than home

Summary MHCA compared to DHCA may have led to a slight statistical decrease in perioperative bleeding (decreased cell saver transfusion, post-operative output) However, this did not translate to clinically apparent benefit such as reduced rate of transfusion or reoperation for bleeding Mortality and morbidity did not appear to differ between patients managed with MHCA vs. DHCA

Potential for unobserved confounding Limitations Potential for unobserved confounding Non-standardization of transfusion and surgical practice over the entire course of the study Lack of functional coagulation assessments

Conclusions Although perioperative bleeding may be slightly lower in MHCA patients, this difference does not correspond to a change in the rate of blood product transfusion or the need for reoperation due to bleeding. The comparable mortality and morbidity observed between the DHCA and MHCA groups confirm the current clinical equipoise between these two strategies and supports the need for prospective study to better elucidate the optimal degree of hypothermia during aortic reconstruction with circulatory arrest.