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Drake DH, Zhang P, Zimmerman KG, Morrow CD, Sidebotham DA. Anatomic, stage-based repair of secondary mitral valve disease. J Thorac Cardiovasc Surg 2024; 167:1733-1744. [PMID: 36775783 DOI: 10.1016/j.jtcvs.2023.01.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Revised: 12/20/2022] [Accepted: 01/05/2023] [Indexed: 01/12/2023]
Abstract
OBJECTIVE Intervention for repair of secondary mitral valve disease is frequently associated with recurrent regurgitation. We sought to determine if there was sufficient evidence to support inclusion of anatomic indices of leaflet dysfunction in the management of secondary mitral valve disease. METHODS We performed a systematic review and meta-analysis of published reports comparing anatomic indices of leaflet dysfunction with the complexity of valve repair and the outcome from intervention. Patients were stratified by the severity of leaflet dysfunction. A secondary analysis was performed comparing outcomes when procedural complexity was optimally matched to severity of leaflet dysfunction and when intervention was not matched to dysfunction. RESULTS We identified 6864 publications, of which 65 met inclusion criteria. An association between the severity of leaflet dysfunction and the procedural complexity was highly predictive of satisfactory freedom from recurrent regurgitation. Patients were categorized into 4 groups based on stratification of leaflet dysfunction. Satisfactory results were achieved in 93.7% of patients in whom repair complexity was appropriately matched to severity of leaflet dysfunction and in 68.8% in whom repair was not matched to dysfunction (odds ratio, 0.148; 95% confidence interval, 0.119-0.184; P < .0001). CONCLUSIONS For patients with secondary mitral valve disease, satisfactory outcome from valve repair improves when procedural complexity is matched to anatomic indices of leaflet dysfunction. Anatomic indices of leaflet dysfunction should be considered when planning interventions for secondary mitral regurgitation. Routine inclusion of anatomic indices in trial design and reporting should facilitate comparison of results and strengthen guidelines. There are sufficient data to support anatomic staging of secondary mitral valve disease.
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Affiliation(s)
- Daniel H Drake
- Department of Cardiac Surgery, University of Michigan Medical School, Ann Arbor, Mich; Department of Surgery, Munson Medical Center, Traverse City, Mich.
| | - Peng Zhang
- Department of Surgery, University of Michigan Medical School, Ann Arbor, Mich
| | | | - Cynthia D Morrow
- Health Systems, Management & Policy, Colorado School of Public Health, Aurora, Colo
| | - David A Sidebotham
- Department of Cardiothoracic Anaesthesia and Cardiothoracic Intensive Care, Auckland City Hospital, Auckland, New Zealand
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Spencer BL, Wilhelm SK, Stephan C, Urrea KA, Palacio DP, Bartlett RH, Drake DH, Rojas-Pena A. Extending heart preservation to 24 h with normothermic perfusion. Front Cardiovasc Med 2024; 11:1325169. [PMID: 38638886 PMCID: PMC11024329 DOI: 10.3389/fcvm.2024.1325169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2023] [Accepted: 02/15/2024] [Indexed: 04/20/2024] Open
Abstract
Cold static storage (CSS) for up to 6 h is the gold standard in heart preservation. Although some hearts stored over 6 h have been transplanted, longer CSS times have increased posttransplant morbimortality. Transmedics® Organ Care System (OCS™) is the only FDA-approved commercial system that provides an alternative to CSS using normothermic ex situ heart perfusion (NEHP) in resting mode with aortic perfusion (Langendorff method). However, it is also limited to 6 h and lacks an objective assessment of cardiac function. Developing a system that can perfuse hearts under NEHP conditions for >24 h can facilitate organ rehabilitation, expansion of the donor pool, and objective functional evaluation. The Extracorporeal Life Support Laboratory at the University of Michigan has worked to prolong NEHP to >24 h with an objective assessment of heart viability during NEHP. An NEHP system was developed for aortic (Langendorff) perfusion using a blood-derived perfusate (leukocyte/thrombocyte-depleted blood). Porcine hearts (n = 42) of different sizes (6-55 kg) were divided into five groups and studied during 24 h NEHP with various interventions in three piglets (small-size) heart groups: (1) Control NEHP without interventions (n = 15); (2) NEHP + plasma exchange (n = 5); (3) NEHP + hemofiltration (n = 10) and two adult-size (juvenile pigs) heart groups (to demonstrate the support of larger hearts); (4) NEHP + hemofiltration (n = 5); and (5) NEHP with intermittent left atrial (iLA) perfusion (n = 7). All hearts with NEHP + interventions (n = 27) were successfully perfused for 24 h, whereas 14 (93.3%) control hearts failed between 10 and 21 h, and 1 control heart (6.6%) lasted 24 h. Hearts in the piglet hemofiltration and plasma exchange groups performed better than those in the control group. The larger hearts in the iLA perfusion group (n = 7) allowed for real-time heart functional assessment and remained stable throughout the 24 h of NEHP. These results demonstrate that heart preservation for 24 h is feasible with our NEHP perfusion technique. Increasing the preservation period beyond 24 h, infection control, and nutritional support all need optimization. This proves the concept that NEHP has the potential to increase the organ pool by (1) considering previously discarded hearts; (2) performing an objective assessment of heart function; (3) increasing the donor/recipient distance; and (4) developing heart-specific perfusion therapies.
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Affiliation(s)
- Brianna L. Spencer
- Extracorporeal Life Support Laboratory, Department of Surgery, University of Michigan Medical School, Ann Arbor, MI, United States
| | - Spencer K. Wilhelm
- Extracorporeal Life Support Laboratory, Department of Surgery, University of Michigan Medical School, Ann Arbor, MI, United States
| | - Christopher Stephan
- Extracorporeal Life Support Laboratory, Department of Surgery, University of Michigan Medical School, Ann Arbor, MI, United States
| | - Kristopher A. Urrea
- Extracorporeal Life Support Laboratory, Department of Surgery, University of Michigan Medical School, Ann Arbor, MI, United States
| | - Daniela Pelaez Palacio
- Extracorporeal Life Support Laboratory, Department of Surgery, University of Michigan Medical School, Ann Arbor, MI, United States
| | - Robert H. Bartlett
- Extracorporeal Life Support Laboratory, Department of Surgery, University of Michigan Medical School, Ann Arbor, MI, United States
| | - Daniel H. Drake
- Extracorporeal Life Support Laboratory, Department of Surgery, University of Michigan Medical School, Ann Arbor, MI, United States
- Department of Cardiac Surgery, University of Michigan Medical School, Ann Arbor, MI, United States
| | - Alvaro Rojas-Pena
- Extracorporeal Life Support Laboratory, Department of Surgery, University of Michigan Medical School, Ann Arbor, MI, United States
- Department of Surgery, Section of Transplantation, University of Michigan Medical School, Ann Arbor, MI, United States
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Dann TM, Spencer BL, Wilhelm SK, Drake SK, Bartlett RH, Rojas-Pena A, Drake DH. Donor heart refusal after circulatory death: An analysis of United Network for Organ Sharing refusal codes. JTCVS Open 2024; 18:91-103. [PMID: 38690428 PMCID: PMC11056494 DOI: 10.1016/j.xjon.2024.02.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 02/04/2024] [Accepted: 02/07/2024] [Indexed: 05/02/2024]
Abstract
Objective Donor hearts procured after circulatory death (DCD) may significantly increase the number of hearts available for transplantation. The purpose of this study was to analyze current DCD and brain-dead donor (DBD) heart transplantation rates and characterize organ refusal using the most up-to-date United Network for Organ Sharing (UNOS) and Organ Procurement and Transplantation Network data. Methods We analyzed UNOS and Organ Procurement and Transplantation Network DBD and DCD candidate, transplantation, and demographic data from 2020 through 2022 and 2022 refusal code data to characterize DCD heart use and refusal. Subanalyses were performed to characterize DCD donor demographics and regional transplantation rate variance. Results DCD hearts were declined 3.37 times more often than DBD hearts. The most frequently used code for DCD refusal was neurologic function, related to concerns of a prolonged dying process and organ preservation. In 2022, 92% (1329/1452) of all DCD refusals were attributed to neurologic function. When compared with DBD, DCD donor hearts were more frequently declined as the result of prolonged warm ischemic time (odds ratio, 5.65; 95% confidence interval, 4.07-7.86) and other concerns over organ preservation (odds ratio, 4.06; 95% confidence interval, 3.33-4.94). Transplantation rate variation was observed between demographic groups and UNOS regions. DCD transplantation rates are currently experiencing second order polynomial growth. Conclusions DCD donor hearts are declined more frequently than DBD. DCD heart refusals result from concerns over a prolonged dying process and organ preservation. Heart transplantation rates may be substantially improved by ex situ hemodynamic assessment, adoption of normothermic regional perfusion guidelines, and quality initiatives.
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Affiliation(s)
- Tyler M. Dann
- Department of Surgery, University of Michigan Medical School, Ann Arbor, Mich
- Department of Surgery, Extracorporeal Life Support Laboratory, University of Michigan Medical School, Ann Arbor, Mich
| | - Brianna L. Spencer
- Department of Surgery, University of Michigan Medical School, Ann Arbor, Mich
- Department of Surgery, Extracorporeal Life Support Laboratory, University of Michigan Medical School, Ann Arbor, Mich
| | - Spencer K. Wilhelm
- Department of Surgery, University of Michigan Medical School, Ann Arbor, Mich
- Department of Surgery, Extracorporeal Life Support Laboratory, University of Michigan Medical School, Ann Arbor, Mich
| | - Sarah K. Drake
- Information School, University of Wisconsin, Madison, Wis
| | - Robert H. Bartlett
- Department of Surgery, University of Michigan Medical School, Ann Arbor, Mich
- Department of Surgery, Extracorporeal Life Support Laboratory, University of Michigan Medical School, Ann Arbor, Mich
| | - Alvaro Rojas-Pena
- Department of Surgery, University of Michigan Medical School, Ann Arbor, Mich
- Department of Surgery, Extracorporeal Life Support Laboratory, University of Michigan Medical School, Ann Arbor, Mich
- Department of Surgery, Section of Transplantation, University of Michigan Medical School, Ann Arbor, Mich
| | - Daniel H. Drake
- Department of Surgery, Extracorporeal Life Support Laboratory, University of Michigan Medical School, Ann Arbor, Mich
- Department of Cardiac Surgery, University of Michigan Medical School, Ann Arbor, Mich
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Spencer BL, Wilhelm SK, Urrea KA, Chakrabortty V, Sewera S, Mazur DE, Niman JB, Bartlett RH, Rojas-Peña A, Drake DH. Twenty-four-hour Normothermic Ex Vivo Heart Perfusion With Low Flow Functional Assessment in an Adult Porcine Model. Transplantation 2024:00007890-990000000-00670. [PMID: 38411562 DOI: 10.1097/tp.0000000000004956] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/28/2024]
Abstract
BACKGROUND Cold static storage and normothermic ex vivo heart perfusion are routinely limited to 6 h. This report describes intermittent left atrial (LA) perfusion that allows cardiac functional assessment in a working heart mode. METHODS Using our adult porcine model, general anesthesia was induced and a complete cardiectomy was performed following cardioplegic arrest. Back-table instrumentation was completed and normothermic ex vivo heart perfusion (NEHP) was initiated in a nonworking heart mode (Langendorff). After 1 h of resuscitation and recovery, LA perfusion was initiated and the heart was transitioned to a coronary flow-only working heart mode for 30 min. Baseline working heart parameters were documented and the heart was returned to nonworking mode. Working heart assessments were performed for 30 min every 6 h for 24 h. RESULTS Twenty-four-hour NEHP on 9 consecutive hearts (280 ± 42.1 g) was successful and no significant differences were found between working heart parameters at baseline and after 24 h of perfusion. There was no difference between initial and final measurements of LA mean pressures (5.0 ± 3.1 versus 9.0 ± 6.5 mm Hg, P = 0.22), left ventricular systolic pressures (44.3 ± 7.2 versus 39.1 ± 9.0 mm Hg, P = 0.13), mean aortic pressures (30.9 ± 5.8 versus 28.1 ± 8.1 mm Hg, P = 0.37), and coronary resistance (0.174 ± 0.046 versus 0.173 ± 0.066 mL/min/g, P = 0.90). There were also no significant differences between lactate (2.4 ± 0.5 versus 2.6 ± 0.4 mmol/L, P = 0.17) and glucose (173 ± 75 versus 156 ± 70 mg/dL, P = 0.37). CONCLUSIONS A novel model using intermittent LA perfusion to create a coronary flow-only working heart mode for assessment of ex vivo cardiac function has been successfully developed.
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Affiliation(s)
- Brianna L Spencer
- Department of Surgery and ECLS Laboratory, University of Michigan Medical School, Ann Arbor, MI
| | - Spencer K Wilhelm
- Department of Surgery and ECLS Laboratory, University of Michigan Medical School, Ann Arbor, MI
| | - Kristopher A Urrea
- Department of Surgery and ECLS Laboratory, University of Michigan Medical School, Ann Arbor, MI
| | - Vikramjit Chakrabortty
- Department of Surgery and ECLS Laboratory, University of Michigan Medical School, Ann Arbor, MI
| | - Sebastian Sewera
- Department of Surgery and ECLS Laboratory, University of Michigan Medical School, Ann Arbor, MI
| | | | - Joseph B Niman
- Department of Surgery and ECLS Laboratory, University of Michigan Medical School, Ann Arbor, MI
| | - Robert H Bartlett
- Department of Surgery and ECLS Laboratory, University of Michigan Medical School, Ann Arbor, MI
| | - Alvaro Rojas-Peña
- Department of Surgery and ECLS Laboratory, University of Michigan Medical School, Ann Arbor, MI
- Department of Surgery, Section of Transplantation, University of Michigan, Ann Arbor, MI
| | - Daniel H Drake
- Department of Surgery and ECLS Laboratory, University of Michigan Medical School, Ann Arbor, MI
- Department of Cardiac Surgery, University of Michigan, Ann Arbor, MI
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Johnson MD, Zimmerman KG, Nakashima T, Urrea KA, Rojas-Pena A, Bartlett RH, Drake DH. Artificial Intelligence-Assisted Strain Echocardiography in an Ex Vivo Heart. ASAIO J 2023; 69:e523-e525. [PMID: 37524082 DOI: 10.1097/mat.0000000000001994] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/02/2023] Open
Affiliation(s)
- Matthew D Johnson
- From the Department of Surgery, University of Michigan Medical School, Ann Arbor, Michigan
| | - Karen G Zimmerman
- Department of Cardiology, Henry Ford Health System, Detroit, Michigan
| | - Takahiro Nakashima
- From the Department of Surgery, University of Michigan Medical School, Ann Arbor, Michigan
| | - Kristopher A Urrea
- From the Department of Surgery, University of Michigan Medical School, Ann Arbor, Michigan
| | - Alvaro Rojas-Pena
- From the Department of Surgery, University of Michigan Medical School, Ann Arbor, Michigan
| | - Robert H Bartlett
- From the Department of Surgery, University of Michigan Medical School, Ann Arbor, Michigan
| | - Daniel H Drake
- Department of Cardiac Surgery, University of Michigan Medical School, Ann Arbor, Michigan
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Spencer BL, Wilhelm SK, Urrea KA, Chakrabortty V, Sewera SJ, Mazur DE, Bartlett RH, Rojas-Peña A, Drake DH. Twenty-Four Hour Normothermic Ex Vivo Heart Perfusion With Hemofiltration In an Adult Porcine Model. Transplant Proc 2023; 55:2241-2246. [PMID: 37783593 DOI: 10.1016/j.transproceed.2023.08.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Accepted: 08/28/2023] [Indexed: 10/04/2023]
Abstract
BACKGROUND Historically, cardiac transplantation relied on cold static storage at 5 °C for ex vivo myocardial preservation. Currently, machine perfusion is the standard of care at many transplant centers. These storage methods are limited to 12 hours. We sought to evaluate the efficacy of hemofiltration and filtrate replacement in adult porcine hearts using normothermic heart perfusion (NEVHP) for 24 hours. METHODS We performed 24-hour NEVHP on 5 consecutive hearts. After anesthetic induction, sternotomy, cardioplegia administration, explantation, and back-table instrumentation, NEVHP was initiated in beating, unloaded mode. After 1 hour, plasma exchange was performed, and hemofiltration was initiated. Heart function parameters and arterial blood gasses were obtained hourly. RESULTS All hearts (n = 5) were viable at the 24-hour mark. The average left ventricular systolic pressure at the beginning of the prep was 36.6 ± 7.9 mm Hg compared with 27 ± 5.5 mm Hg at the end. Coronary resistance at the beginning of prep was 0.79 ± 0.10 mm Hg/L/min and 0.93 ± 0.28 mm Hg/L/min at the end. Glucose levels averaged 223 ± 13.9 mg/dL, and the lactate average at the termination of prep was 2.6 ± 0.3 mmol/L. CONCLUSIONS We successfully perfused adult porcine hearts at normothermic temperatures for 24 hours with results comparable to our pediatric porcine heart model. The next step in our research is NEVHP evaluation in a working mode using left atrial perfusion.
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Affiliation(s)
- Brianna L Spencer
- Department of Surgery and ECLS Laboratory, University of Michigan Medical School, Ann Arbor, MI
| | - Spencer K Wilhelm
- Department of Surgery and ECLS Laboratory, University of Michigan Medical School, Ann Arbor, MI
| | - Kristopher A Urrea
- Department of Surgery and ECLS Laboratory, University of Michigan Medical School, Ann Arbor, MI
| | - Vikramjit Chakrabortty
- Department of Surgery and ECLS Laboratory, University of Michigan Medical School, Ann Arbor, MI
| | - Sebastian J Sewera
- Department of Surgery and ECLS Laboratory, University of Michigan Medical School, Ann Arbor, MI
| | | | - Robert H Bartlett
- Department of Surgery and ECLS Laboratory, University of Michigan Medical School, Ann Arbor, MI
| | - Alvaro Rojas-Peña
- Department of Surgery and ECLS Laboratory, University of Michigan Medical School, Ann Arbor, MI; Department of Surgery, Section of Transplantation, University of Michigan, Ann Arbor, MI
| | - Daniel H Drake
- Department of Surgery and ECLS Laboratory, University of Michigan Medical School, Ann Arbor, MI; Department of Cardiac Surgery, University of Michigan, Ann Arbor, MI.
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Sade RM, Carpenter AJ, D'Amico TA, Drake DH, Entwistle JW, Ray S. China's Opaque Wall of Secrecy. Ann Thorac Surg 2023; 115:1088-1089. [PMID: 35690134 DOI: 10.1016/j.athoracsur.2022.05.030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Revised: 05/19/2022] [Accepted: 05/22/2022] [Indexed: 11/26/2022]
Affiliation(s)
- Robert M Sade
- Department of Surgery, Institute of Human Values in Health Care, Medical University of South Carolina, 30 Courtenay Dr, MSC 295, Charleston, SC 29425-2950.
| | - Andrea J Carpenter
- Division of Thoracic Surgery, University of Texas Health Science Center, San Antonio, Texas
| | - Thomas A D'Amico
- Department of Surgery, Duke University Medical Center, Durham, North Carolina
| | - Daniel H Drake
- Department of Surgery, Munson Healthcare, Traverse City, Michigan
| | - John W Entwistle
- Division of Cardiothoracic Surgery, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Shuddhadeb Ray
- Department of Surgery, Washington University School of Medicine, St Louis, Missouri
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Prater AR, Fallon BP, Hirschl RB, Drake DH, Rojas-Pena A. Novel Left Atrial Cannulation Technique for Attachment of a Pumpless Artificial Lung. ASAIO J 2022; 68:1071-1073. [PMID: 35905308 PMCID: PMC9346620 DOI: 10.1097/mat.0000000000001693] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
A pumpless artificial lung has the potential to provide a bridge to recovery or transplantation in children with respiratory failure. Pulmonary artery inflow and left atrial outflow are necessary for low-gradient, pumpless systems; however, long-term cannulation of the fragile left atrium remains problematic. In this technique, the left atrium and pulmonary artery were exposed through a left anterior thoracotomy. Inflow to the artificial lung was created using an end-to-side anastomosis with the pulmonary artery. Device outflow was established through the left atrium. A single-stage venous cannula was passed through a free PTFE graft. Using polypropylene with pledgets, two concentric purse-string sutures were placed in the dome of the left atrium. The venous cannula was inserted. The graft was slid down the cannula and circumferentially secured to the adjacent left atrial tissue and pledgets. The other end of the graft was secured to the cannula with silk ties. The procedure was successful in 10 sheep. Initial device blood flow was 969 ± 222 ml/min, which remained stable for up to 7 days with no anastomotic complications. This is an effective method of achieving secure, long-term left atrial cannulation without cardiopulmonary bypass for use in a low-resistance, pumpless artificial lung. And, most importantly, improves the ease and safety of cannula replacement and final decannulation when AL support is no longer required.
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Affiliation(s)
- Aaron R Prater
- From the Extracorporeal Life Support Laboratory, Department of Surgery, Michigan Medicine, Ann Arbor, Michigan
| | - Brian P Fallon
- From the Extracorporeal Life Support Laboratory, Department of Surgery, Michigan Medicine, Ann Arbor, Michigan
| | - Ronald B Hirschl
- From the Extracorporeal Life Support Laboratory, Department of Surgery, Michigan Medicine, Ann Arbor, Michigan
- Section of Pediatric Surgery, Department of Surgery, Michigan Medicine, Ann Arbor, Michigan
| | - Daniel H Drake
- From the Extracorporeal Life Support Laboratory, Department of Surgery, Michigan Medicine, Ann Arbor, Michigan
| | - Alvaro Rojas-Pena
- From the Extracorporeal Life Support Laboratory, Department of Surgery, Michigan Medicine, Ann Arbor, Michigan
- Section of Transplantation Surgery, Department of Surgery, Michigan Medicine, Ann Arbor, Michigan
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Sade RM, Carpenter AJ, D'Amico TA, Drake DH, Entwistle JW, Ray S. Reply: The boat, the sword, and the opacity of Chinese transplant data. J Thorac Cardiovasc Surg 2022; 164:e129-e130. [PMID: 35715273 DOI: 10.1016/j.jtcvs.2022.05.027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/25/2022] [Revised: 05/25/2022] [Accepted: 05/25/2022] [Indexed: 11/16/2022]
Affiliation(s)
- Robert M Sade
- Department of Surgery, Institute of Human Values in Health Care, Medical University of South Carolina, Charleston, SC
| | - Andrea J Carpenter
- Division of Thoracic Surgery, University of Texas Health Science Center, San Antonio, Tex
| | - Thomas A D'Amico
- Department of Surgery, Duke University Medical Center, Durham, NC
| | - Daniel H Drake
- Department of Surgery, Munson Healthcare, Traverse City, Mich
| | - John W Entwistle
- Division of Cardiothoracic Surgery, Thomas Jefferson University, Philadelphia, Pa
| | - Shuddhadeb Ray
- Department of Surgery, Washington University School of Medicine, St Louis, Mo
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Entwistle JW, Drake DH, Fenton KN, Smith MA, Sade RM. Normothermic Regional Perfusion: Ethical Issues in Thoracic Organ Donation. Ann Thorac Surg 2022; 114:44-51. [PMID: 35589419 DOI: 10.1016/j.athoracsur.2022.01.058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2021] [Accepted: 01/12/2022] [Indexed: 11/18/2022]
Affiliation(s)
- John W Entwistle
- Division of Cardiothoracic Surgery, Department of Surgery, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Daniel H Drake
- Department of Cardiac Surgery, University of Michigan Medical School, Ann Arbor, Michigan
| | | | - Michael A Smith
- Norton Thoracic Institute, St Joseph's Hospital and Medical Center, Phoenix, Arizona
| | - Robert M Sade
- Division of Cardiothoracic Surgery, Department of Surgery, Medical University of South Carolina, Charleston, South Carolina.
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11
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Entwistle JW, Sade RM, Drake DH. Clinical xenotransplantation seems close: Ethical issues persist. Artif Organs 2022; 46:987-994. [PMID: 35451522 DOI: 10.1111/aor.14255] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Accepted: 03/23/2022] [Indexed: 01/25/2023]
Abstract
Scientific barriers that have prevented successful xenotransplantation are being breached, yet many ethical issues remain. Some are broad issues that accompany the adoption of novel and expensive technologies, and some are unique to xenotransplantation. Major ethical questions include areas such as: viral transmission; zoonoses and lifetime surveillance; interfering with nature; efficacy, access, and expense; treatment of animals; regulation and oversight.
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Affiliation(s)
- John W Entwistle
- Department of Surgery, Division of Cardiothoracic Surgery, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Robert M Sade
- Department of Surgery, Division of Cardiothoracic Surgery, Medical University of South Carolina, Charleston, South Carolina, USA
| | - Daniel H Drake
- Department of Cardiac Surgery, University of Michigan Medical School, Ann Arbor, Michigan, USA
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12
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Entwistle JW, Drake DH, Fenton KN, Smith MA, Sade RM. Normothermic regional perfusion: Ethical issues in thoracic organ donation. J Thorac Cardiovasc Surg 2022; 164:147-154. [PMID: 35369998 DOI: 10.1016/j.jtcvs.2022.01.018] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2021] [Revised: 01/05/2022] [Accepted: 01/12/2022] [Indexed: 01/20/2023]
Affiliation(s)
- John W Entwistle
- Division of Cardiothoracic Surgery, Department of Surgery, Thomas Jefferson University, Philadelphia, Pa
| | - Daniel H Drake
- Department of Cardiac Surgery, University of Michigan Medical School, Ann Arbor, Mich
| | | | - Michael A Smith
- Norton Thoracic Institute, St Joseph's Hospital and Medical Center, Phoenix, Ariz
| | - Robert M Sade
- Division of Cardiothoracic Surgery, Department of Surgery, Medical University of South Carolina, Charleston, SC.
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13
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Sade RM, Carpenter AJ, D'Amico TA, Drake DH, Entwistle JW, Ray S, Tweddell JS. Unethical Studies on Transplantation in Cardiothoracic Surgery Journals. Ann Thorac Surg 2021; 112:1746-1752. [PMID: 34654543 DOI: 10.1016/j.athoracsur.2021.07.070] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 06/25/2021] [Accepted: 07/25/2021] [Indexed: 01/06/2023]
Affiliation(s)
- Robert M Sade
- Department of Surgery, Institute of Human Values in Health Care, Medical University of South Carolina, Charleston, South Carolina.
| | - Andrea J Carpenter
- Division of Thoracic Surgery, University of Texas Health Science Center, San Antonio, Texas
| | - Thomas A D'Amico
- Department of Surgery, Duke University Medical Center, Durham, North Carolina
| | - Daniel H Drake
- Department of Surgery, Munson Healthcare, Traverse City, Michigan
| | - John W Entwistle
- Division of Cardiothoracic Surgery, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Shuddhadeb Ray
- Department of Surgery, Washington University in St. Louis School of Medicine, St Louis, Missouri
| | - James S Tweddell
- Department of Surgery, Cincinnati Children's Hospital Medical Center, Heart Institute, Cincinnati, Ohio
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Sade RM, Carpenter AJ, D'Amico TA, Drake DH, Entwistle JW, Ray S, Tweddell JS. Unethical studies on transplantation in cardiothoracic surgery journals. J Thorac Cardiovasc Surg 2021; 162:1647-1653. [PMID: 34654563 DOI: 10.1016/j.jtcvs.2021.07.061] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 07/25/2021] [Accepted: 07/25/2021] [Indexed: 01/06/2023]
Affiliation(s)
- Robert M Sade
- Department of Surgery, Institute of Human Values in Health Care, Medical University of South Carolina, Charleston, SC.
| | - Andrea J Carpenter
- Division of Thoracic Surgery, University of Texas Health Science Center, San Antonio, Tex
| | - Thomas A D'Amico
- Department of Surgery, Duke University Medical Center, Durham, NC
| | - Daniel H Drake
- Department of Surgery, Munson Healthcare, Traverse City, Mich
| | - John W Entwistle
- Division of Cardiothoracic Surgery, Thomas Jefferson University, Philadelphia, Pa
| | - Shuddhadeb Ray
- Department of Surgery, Washington University in St. Louis School of Medicine, St Louis, Mo
| | - James S Tweddell
- Department of Surgery, Cincinnati Children's Hospital Medical Center, Heart Institute, Cincinnati, Ohio
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15
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Drake DH, Zimmerman KG, Sidebotham DA. Past, current and future management of secondary mitral valve disease: the importance of anatomic staging. Ann Transl Med 2020; 8:968. [PMID: 32953768 PMCID: PMC7475447 DOI: 10.21037/atm.2020.03.82] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Affiliation(s)
- Daniel H Drake
- Department of Surgery, Munson Medical Center, Traverse City, MI, USA
| | - Karen G Zimmerman
- Department of Cardiology, Henry Ford Health System, Detroit, MI, USA
| | - David A Sidebotham
- Department of Cardiothoracic Anesthesia and Cardiothoracic Intensive Care Unit, Auckland City Hospital, Grafton, Auckland, New Zealand
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16
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Drake DH, De Bonis M, Covella M, Agricola E, Zangrillo A, Zimmerman KG, Cobey FC. Echocardiography in Pandemic: Front-Line Perspective, Expanding Role of Ultrasound, and Ethics of Resource Allocation. J Am Soc Echocardiogr 2020; 33:683-689. [PMID: 32503707 PMCID: PMC7151341 DOI: 10.1016/j.echo.2020.04.007] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2020] [Revised: 04/04/2020] [Accepted: 04/04/2020] [Indexed: 02/06/2023]
Abstract
The grave clinical context of the coronavirus disease 2019 (COVID-19) pandemic must be understood. Italy is immersed in the COVID-19 pandemic. Most of the world will soon follow. The United States currently has the most documented cases of COVID-19 of any nation. Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2)-associated acute cardiomyopathy is common in critical care patients and is associated with a high mortality rate. Patients with COVID-19 frequently require mechanical support for adequate oxygenation. A severe shortfall of ventilators is predicted. Of equal concern is the projected shortage of trained professionals required to care for patients on mechanical ventilation. Ultrasonography is proving to be a valuable tool for identifying the pulmonary manifestations and progression of COVID-19. Lung ultrasound also facilitates successful weaning from mechanical ventilation. Ultrasonography of the lung, pleura, and diaphragm are easily mastered by experienced echocardiographers. Echocardiography has an established role for optimal fluid management and recognition of cardiac disease, including SARS-CoV-2-associated acute cardiomyopathy. Cardiologists, anesthesiologists, sonographers, and all providers should be prepared to commit their full spectrum of skills to mitigate the consequences of the pandemic. We should also be prepared to collaborate and cross-train to expand professional services as necessary. During a declared health care crisis, providers must be familiar with the ethical principles, organizational structure, practical application, and gravity of limited resource allocation.
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Affiliation(s)
| | - Michele De Bonis
- Vita-Salute San Raffaele University, San Raffaele University Hospital, Milan, Italy
| | | | - Eustachio Agricola
- Vita-Salute San Raffaele University, San Raffaele University Hospital, Milan, Italy
| | - Alberto Zangrillo
- Vita-Salute San Raffaele University, San Raffaele University Hospital, Milan, Italy
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17
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Drake DH. To Clip or Not to Clip: The Use of MitraClip Therapy for Functional Mitral Regurgitation. J Cardiothorac Vasc Anesth 2020; 34:1690-1692. [PMID: 32127282 DOI: 10.1053/j.jvca.2020.01.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2020] [Accepted: 01/06/2020] [Indexed: 11/11/2022]
Affiliation(s)
- Daniel H Drake
- Department of Surgery, Munson Medical Center, Traverse City, MI
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18
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Drake DH. Invited Commentary. Ann Thorac Surg 2020; 109:677. [DOI: 10.1016/j.athoracsur.2019.11.030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Accepted: 11/25/2019] [Indexed: 10/25/2022]
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19
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Drake DH. Bicuspid Aortic Valve Disease, False Aneurysms, and the Role of Echocardiography: Surgical Context and Perspective. J Cardiothorac Vasc Anesth 2019; 33:1471-1472. [PMID: 30616895 DOI: 10.1053/j.jvca.2018.11.032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Indexed: 11/11/2022]
Affiliation(s)
- Daniel H Drake
- Department of Surgery, Munson Medical Center, Traverse City, MI
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20
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Drake CE, Drake DH, Sidebotham DA. Invited Commentary. Ann Thorac Surg 2016; 102:1051. [PMID: 27645941 DOI: 10.1016/j.athoracsur.2016.05.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Revised: 04/29/2016] [Accepted: 05/02/2016] [Indexed: 11/28/2022]
Affiliation(s)
- Cynthia E Drake
- Health Care Policy and Research, University of Colorado School of Medicine, Aurora, Colorado
| | - Daniel H Drake
- Cardiothoracic Surgery, Munson Medical Center, 1221 Sixth St, Ste 202, Traverse City, MI 49684.
| | - David A Sidebotham
- Cardiothoracic Anaesthesia and Cardiothoracic Intensive Care, Auckland City Hospital, Auckland, New Zealand
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21
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Affiliation(s)
- Daniel H. Drake
- From the Departments of Cardiology and Surgery, Munson Medical Center, Traverse City, MI
| | - Karen G. Zimmerman
- From the Departments of Cardiology and Surgery, Munson Medical Center, Traverse City, MI
| | - Anne M. Hepner
- From the Departments of Cardiology and Surgery, Munson Medical Center, Traverse City, MI
| | - Cynthia D. Nichols
- From the Departments of Cardiology and Surgery, Munson Medical Center, Traverse City, MI
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22
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Drake DH. Invited commentary. Ann Thorac Surg 2010; 90:495-6. [PMID: 20667336 DOI: 10.1016/j.athoracsur.2010.05.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/22/2010] [Revised: 04/28/2010] [Accepted: 05/03/2010] [Indexed: 11/19/2022]
Affiliation(s)
- Daniel H Drake
- Cardiothoracic Surgery Munson Medical Center 1221 Sixth St, Ste 202 Traverse City, MI 49684, USA.
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23
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Abstract
Parabolic resection, named for the shape of the cut edges of the excised tissue, expands on a common 'trick' used by experienced mitral surgeons to preserve tissue and increase the probability of successful repair. Our objective was to describe and clinically analyze this simple modification of conventional resection. Thirty-six patients with mitral regurgitation underwent valve repair using parabolic resection in combination with other techniques. Institution specific mitral data, Society of Thoracic Surgeons data and preoperative, post-cardiopulmonary bypass (PCPB) and postoperative echocardiography data were collected and analyzed. Preoperative echocardiography demonstrated mitral regurgitation ranging from moderate to severe. PCPB transesophageal echocardiography demonstrated no regurgitation or mild regurgitation in all patients. Thirty-day surgical mortality was 2.8%. Serial echocardiograms demonstrated excellent repair stability. One patient (2.9%) with rheumatic disease progressed to moderate regurgitation 33 months following surgery. Echocardiography on all others demonstrated no or mild regurgitation at a mean follow-up of 22.8+/-12.8 months. No patient required mitral reintervention. Longitudinal analysis demonstrated 80% freedom from cardiac death, reintervention and greater than moderate regurgitation at four years following repair. Parabolic resection is a simple technique that can be very useful during complex mitral reconstruction. Early and intermediate echocardiographic studies demonstrate excellent results.
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Affiliation(s)
- Daniel H Drake
- Section of Cardiothoracic Surgery, Department of Surgery, Munson Medical Center, Traverse City, MI 49684, USA.
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24
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Drake DH. Invited Commentary. Ann Thorac Surg 2008; 86:63. [DOI: 10.1016/j.athoracsur.2008.04.114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2008] [Revised: 04/05/2008] [Accepted: 04/17/2008] [Indexed: 11/26/2022]
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Abstract
PURPOSE Sternal wire placement frequently results in glove disruption, wound contamination and personnel skin puncture. The described cutting clamp was developed to simplify sternotomy closure and reduce complications. DESCRIPTION Informed consent was obtained from 103 patients who underwent a variety of common cardiac surgical procedures. In each instance, once the cardiac portion of the procedure was completed, the median sternotomy was closed using standard sternal wires and the described cutting clamps. A single set of clamps was repeatedly re-sterilized and used for all cases. EVALUATION There were no incidents of unintentional clamp release, glove disruption or personnel skin punctures from the wire. None of the patients had clinically evident sternal wound infections or nonunion. There were no deaths. The functional attributes of the clamps remained constant throughout the study, and no significant wear was detected on the carbide inserts or other components of the clamps. CONCLUSIONS The sternal wire-cutting clamp simplifies sternal closure and should reduce complications.
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Affiliation(s)
- Daniel H Drake
- Department of Surgery, Section of Cardiothoracic Surgery, Munson Medical Center, Traverse City, Michigan, USA.
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26
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Drake DH, Fry WJ. Ductal drainage for chronic pancreatitis. Surgery 1989; 105:131-40. [PMID: 2916177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The operative experience of 23 patients with chronic or chronic relapsing pancreatitis who underwent ductal drainage is reviewed. All of those studied were treated for pain directly related to their pancreatitis and had no evidence of pseudocyst. Each patient was followed up for a minimum of 5 years postoperatively. In those persons with a diffusely dilated duct or "chain of lakes" pattern seen on ERCP, ductal drainage was preferred to pancreatic resection because of lower mortality and preservation of endocrine function. Internal ductal drainage as described by Partington, Rochelle, and Thal was the procedure of choice because it provides excellent pain relief and splenectomy is not required. Good or excellent long-term pain relief was achieved in 90% of patients undergoing operative intervention. Ductal drainage was frequently complicated by peptic ulcer disease. Postoperative antacid or histamine blocker therapy is recommended.
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Affiliation(s)
- D H Drake
- Department of Surgery, University of Texas Southwestern Medical Center, Dallas 75235
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Bove EL, Gallagher KP, Drake DH, Lynch MJ, Fox M, Forder J, Bolling SF, Shlafer M. The effect of hypothermic ischemia on recovery of left ventricular function and preload reserve in the neonatal heart. J Thorac Cardiovasc Surg 1988; 95:814-8. [PMID: 3361929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Neonatal and adult myocardium respond differently to ischemia. In addition, the neonatal heart possesses a limited preload reserve. The effect of uninterrupted hypothermic ischemia on recovery of left ventricular function and preload reserve was studied in two groups of isolated rabbit hearts: group 1 (neonates, n = 8), 7 to 10 days old; group 2 (adults, n = 15), 6 to 12 months old. Peak left ventricular systolic pressure, the first derivative of left ventricular systolic pressure, and heart rate were measured at left ventricular pressures of 0, 5, 10, and 15 mm Hg before and after 120 minutes of global ischemia at 27 degrees C. Before ischemia, left ventricular systolic pressure increased significantly at each increment of left ventricular end-diastolic pressure for both groups of hearts. After hypothermic ischemia, recovery of left ventricular systolic pressure was significantly reduced at each level of left ventricular end-diastolic pressure among neonatal hearts (range 75% to 79% of control values). The postischemic recovery of left ventricular systolic pressure in the adult hearts was markedly reduced from baseline values (range 43% to 53% of control values) and was significantly worse than that of neonatal hearts at each level of left ventricular end-diastolic pressure (p less than 0.001). Both groups were able to respond to increasing preload after ischemia. The slope of the curve describing the relationship between left ventricular end-diastolic pressure and percent recovery of left ventricular systolic pressure was not different from zero for neonatal hearts but was significantly greater than zero among the adults (0.22 +/- 0.21 versus 0.73 +/- 0.07, p = 0.0056). After ischemia, the first derivative of left ventricular systolic pressure fell significantly from control values among neonatal hearts (71% of control values). The reduction was considerably greater, however, among the adult hearts (54% of control values). These data indicate that the neonatal heart recovers systolic function better than the adult heart after global ischemia with moderate hypothermia.
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Affiliation(s)
- E L Bove
- Department of Surgery, University of Michigan Medical School, Ann Arbor 48109-0344
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Drake DH, McClanahan TB, Ning XH, Gerren RA, Dunham WR, Gallagher KP. Changes in contractility fail to alter the size of the functional border zone in anesthetized dogs. Circ Res 1987; 61:166-80. [PMID: 3621483 DOI: 10.1161/01.res.61.2.166] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The functional border zone is nonischemic myocardium that exhibits reduced function adjacent to an ischemic area. To determine if the functional border zone can be modified by pharmacologic interventions that alter contractility, we infused isoproterenol (0.04-0.10 micrograms/kg/min) or administered propranolol (2 mg/kg) during circumflex coronary occlusion in nine anesthetized, open-chest dogs. We measured systolic wall thickening on both sides of the perfusion boundary, which was delineated with myocardial blood flow (microsphere) maps constructed from small tissue samples. By fitting sigmoid curves to the composite systolic wall thickening data after coronary occlusion, we modeled the distribution of functional impairment across the perfusion boundary. Defined as the distance from the perfusion boundary to 97.5% of the nonischemic asymptote of the sigmoid fits, the functional border zone was 31 degrees of circumference after coronary occlusion alone. Isoproterenol increased +dP/dt by 58% and augmented nonischemic systolic wall thickening without changing the lateral extent of the functional border zone (32 degrees). Propranolol reduced +dP/dt by 24% and depressed nonischemic systolic wall thickening, but the size of the functional border zone remained limited to 28 degrees. Within the functional border zone, wall thickening was significantly but only moderately reduced (-28%) compared with thickening in nonischemic myocardium more than 10 mm away from the perfusion boundary. The ratio of nonischemic border zone to central nonischemic area wall thickening remained the same with each intervention. We conclude that the dimensions of the functional border zone are fixed early after coronary occlusion and that inotropic interventions do not modify the extent or relative severity of nonischemic regional dysfunction.
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Abstract
To evaluate how aortic constriction affects nonischemic myocardium adjacent to the perfusion boundary (the "functional border zone"), we measured systolic wall thickening (dWT) with sonomicrometers in eight anesthetized, open-chest dogs. The locations of the wall thickening measurements relative to the perfusion boundary (PB) were determined with myocardial blood flow (microspheres) maps constructed from multiple, small tissue samples. In nonischemic myocardium more than 10 mm from the PB produced by circumflex coronary occlusion, dWT increased significantly from 2.57 +/- 0.62 (mean +/- SD) to 3.24 +/- 0.73 mm (P less than 0.01). Within 10 mm of the PB, however, dWT did not change significantly (2.48 +/- 0.79 to 2.38 +/- 0.66 mm, NS). When the aorta was mechanically constricted, peak systolic pressure increased approximately 50%. Wall thickening decreased to the same relative degree in nonischemic muscle less than 10 mm and more than 10 mm from the perfusion boundary. By fitting sigmoid curves to the data, we estimated the extent of nonischemic dysfunction. It averaged 26 +/- 6 degrees (6-8 mm of endocardial circumference) during coronary occlusion alone and it was not significantly different (29 +/- 11 degrees) after aortic constriction. Thus elevated afterload affects nonischemic myocardium uniformly and does not increase the size or relative severity of the functional border zone.
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