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Pro: Cardiothoracic Anesthesiologists Should Provide Anesthetic Care for Patients With Ventricular Assist Devices Undergoing Noncardiac Surgery
PRO AND CON Michelle Capdeville, MD Section Editor
Pro: Cardiothoracic Anesthesiologists Should Provide Anesthetic Care for Patients With Ventricular Assist Devices Undergoing Noncardiac Surgery Nicoleta Stoicea, MD, PhD,* Fabrizzio Sacchet-Cardozo, MD,* Nicholas Joseph,† Ahmet Kilic, MD,‡ Angela Sipes,* and Michael Essandoh, MD*
T
HE DEVELOPMENT of the left ventricular assist device (LVAD) has increased the life expectancy of patients with advanced heart failure significantly.1–3 Consequently, LVADs are being implanted at a rate of more than 2,000 devices per year in the United States, comparable to the annual number of heart transplantations performed. Due to this high rate of implantation and a 4-year survival rate, which now nears 50%, LVAD-supported patients presenting for noncardiac surgery have become increasingly common.1–6 According to the seventh report of the Interagency Registry for Mechanical Assist Circulatory Support (INTERMACS), 490% of LVAD implantations are continuous-flow (CF) devices such as the HeartMate II (St. Jude Medical, St. Paul, MN) and the Heartware HVAD (Heartware International Inc., Framingham, MA), with the HeartMate II being the most implanted LVAD, being approved for destination therapy and as a bridge to transplant.7–9 Despite the proven safety and efficacy of LVAD therapy, a significant number of LVAD-supported patients undergo noncardiac surgery because of complications associated with LVAD therapy.3–5,10 Noncardiac surgeries inclusive of hernia repairs; bowel resections; urologic procedures; and ear, nose, and throat surgeries have been reported in LVAD patients.2,8 Gastrointestinal bleeding also is a common complication associated with CF-LVAD therapy based on the need for antiplatelet and anticoagulation therapy, the high incidence of pathologic arteriovenous malformations, and von Willebrand factor conformational changes produced by continuous blood flow in the pump; as such, patients with CF-LVADs frequently require endoscopy.8,10–12 Additionally, between 2.5% and 10% of LVAD patients will experience intracranial hemorrhage secondary to anticoagulation therapy, and may require emergent craniotomies.8,12 Because of the increased risk for complications related to LVAD therapy, cardiothoracic anesthesiology services often are required when these patients present for noncardiac surgery. CONTINUOUS-FLOW LEFT VENTRICULAR ASSIST DEVICE COMPONENTS AND FUNCTIONALITY
Continuous-flow LVADs have 3 components: an inflow cannula that is implanted at the apex of the left ventricle (LV) and attaches to the pump, an axial pump (HeartMate II) or a centrifugal pump (Heartware HVAD) that unloads the LV, and an outflow graft that connects the pump to the ascending aorta.11,12
Appropriate functionality of the CF-LVAD is determined by the following LVAD parameters: pump flow, power consumption, pulsatility index, and pump speed.11 The implanting physician determines the pump speed, whereas the pump flow is derived from the power consumption of the pump.11 The pulsatility index reflects the contribution of the contractility of the native LV to cardiac output and serves as an index of LV preload and inotropy.12 Indepth knowledge of these CF-LVAD parameters is crucial during patient care and may affect hemodynamic management during noncardiac surgery. Accordingly, anesthesiologists caring for CFLVAD patients undergoing noncardiac surgery should understand the CF-LVAD parameters described above before proceeding to the operating room.3 Furthermore, considering that approximately 91% of patients with CF-LVADs who underwent noncardiac surgery had a HeartMate II, anesthesiologists should be particularly familiar with the specifications of this device.13 ANESTHETIC CONSIDERATIONS FOR NONCARDIAC SURGICAL PROCEDURES
Preoperative Assessment The delicate nature of patients with CF-LVADs presenting for noncardiac surgery necessitates a detailed preoperative assessment prior to proceeding with surgery. Interrogation of the CF-LVAD by a VAD coordinator or a perfusionist may provide the anesthesiologist with vital data regarding the functionality of the device in the prior months.11,12 Laboratory tests and imaging studies such as a chest radiograph also should be obtained, and prior echocardiograms should be reviewed to determine right ventricular function after CF-LVAD
From the Departments of *Anesthesiology; †Neuroscience; and ‡Surgery, Wexner Medical Center, The Ohio State University, Columbus, OH. Address reprint requests to Michael Essandoh, MD, Department of Anesthesiology, Division of Cardiothoracic and Vascular Anesthesiology, The Ohio State University, Wexner Medical Center, Doan Hall N 411, 410 W 10th Ave., Columbus, OH. 43210. E-mail: Michael. [email protected] © 2016 Elsevier Inc. All rights reserved. 1053-0770/2602-0034$36.00/0 http://dx.doi.org/10.1053/j.jvca.2016.06.030 Key Words: left ventricular assist device, noncardiac surgery, cardiothoracic anesthesiologists, left ventricular assist device parameters
Journal of Cardiothoracic and Vascular Anesthesia, Vol ], No ] (Month), 2016: pp ]]]–]]]
1
2
STOICEA ET AL
implantation.11 Before administering anesthesia, it is imperative that anesthesiologists managing CF-LVAD patients be familiar not only with LVAD physiology, but also the control algorithms to ensure patient safety.
because of the complexity of CF-LVAD physiology.11,15 To ensure timely therapy for hypotension, inotropic and vasopressor medications should be available readily during induction. SUCTION EVENTS
INTRAOPERATIVE CONSIDERATIONS
Monitoring Hemodynamic monitoring in patients with CF-LVADs remains a challenge because of the nonpulsatile nature of these devices. The anesthesiologist’s ability to monitor patient hemodynamics by automated oscillometric blood pressure (BP) and pulse oximetry may be impaired because of decreased arterial flow pulsatility.2,3,5,10-12 Accordingly, invasive BP monitoring is utilized in a majority of cases.11 In a survey by Sheu et al, 83.8% of respondents from institutions with small LVAD patient populations and 65.8% from institutions with large LVAD patient populations confirmed the use of invasive monitoring in addition to standard American Society of Anesthesiologists monitors for LVADpatient management during noncardiac surgery. For hemodynamic monitoring, arterial catheterization (71.2%), pulmonary arterial catheters (1.3%), central venous catheters (12.0%), and transesophageal echocardiography (TEE) (14.6%) were utilized in minor procedures. The study concluded that 72.5% of noncardiac surgical cases employed 1 or more methods of invasive monitoring.10 In contrast, Stone et al reported arterial line use in only 44% of cases overall, central venous catheter use in 27% of cases, pulmonary arterial catheter use in 10% of cases, and TEE utilization in 14.4% of cases.3 Moreover, 77% of reviewed cases of noncardiac procedures in LVAD patients between 2012 and 2013 did not use invasive BP monitoring.4,10 Contrasting Sheu and Stone’s studies, TEE was implemented in only 3% of patients in a case series reported by Barbara et al.2 According to Hessel et al, TEE and transthoracic echocardiography play an important role in hemodynamic evaluation and adjustment of the pump during noncardiac surgery.13 TEE provides structural and functional information pertaining to LVAD management such as right ventricular geometry and systolic function, in addition to the positions of the interventricular septum and the inflow cannula.12 These data may be essential to guide volume management and pump speed selection, and may further help avoid suction events.13,14 Monitoring LVAD parameters, such as flow, pulsatility index, and LVAD speed, is mandatory.1,2 With regard to the monitoring of oxygenation, near-infrared cerebral spectroscopy, as a substitute for pulse oximetry, has found particular use in the anesthetic management of CFLVAD patients, as this technique does not rely upon pulsatile flow.2,3,10,13 INDUCTION AND MAINTENANCE OF GENERAL ANESTHESIA
The majority of surgeries in CF-LVAD patients are performed with general anesthesia or monitored anesthesia care.15 Regional anesthesia is employed rarely, considering the need for chronic anticoagulation therapy and the high incidence of hepatic dysfunction in the CF-LVAD population.8,13 Induction and maintenance of general anesthesia can be challenging
Understanding the physiology of CF-LVADs is important for the provision of anesthetic care to this population.15 Hemodynamic management of CF-LVAD patients involves accounting for conditions that may impart significant strain on the right ventricle, such as hypoxia, hypercarbia, circulatory overload, lung hyperinflation, light anesthetic depth, and acidosis.12 These complications should be avoided as they may lead to increased risk of right ventricular failure and low CF-LVAD flows. LV preload maintenance also is essential to establishing adequate CF-LVAD flows, and may help in preventing suction events and associated ventricular arrhythmias.2,12,15 In addition to blood and fluid loss, positive-pressure ventilation, reverse Trendelenburg positioning, lateral decubitus positioning, and pneumoperitoneum may impair venous return, thereby triggering suction events.11 Awareness of increased risks for CF-LVAD patients and associated complications during hemodynamic management is recommended, and caution is advised.13,15,16 CARDIOVASCULAR DRUG SUPPORT
Systemic vascular resistance must be managed to ensure an adequate end-organ perfusion.5 Up to 72% of CF-LVAD patients required cardiovascular drug support, implying a need for trained provider involvement in inotrope and vasopressor support, and general LVAD patient management.2,13 It is recommended that mean arterial pressure (MAP) be maintained between 70 mmHg and 80 mmHg in CF-LVAD patients, for which trained provider involvement is especially advised by many authors.13 Higher MAPs, however, can reduce CFLVAD flows and promote pump stasis, a known risk factor for pump thrombosis. Considering that anticoagulation and antiplatelet therapy may be interrupted for surgery, optimal MAPs should be maintained to avoid pump thrombosis. BLOOD REQUIREMENTS AND ANTICOAGULATION
Development of complex coagulopathy during CF-LVAD therapy increases the need for blood-product transfusion during noncardiac surgery.1,2 Blood transfusions may increase pulmonary vascular resistance, reducing LV preload and CFLVAD flow.1 Reversal of anticoagulation may be considered depending on the patient’s bleeding risk and thrombotic history and the surgical procedure performed.2,13 The model of CFLVAD implanted also may dictate the level of anticoagulation, as some studies suggest the HeartMate II requires lower levels of anticoagulation than other CF-LVAD devices.12,13 However, specific guidelines do not exist, and high rates of bleeding complications have been reported during noncardiac surgery, reaching a 44% incidence in Taghavi et al’s study.17 ADVANCED CARDIOVASCULAR LIFE SUPPORT
Ventricular arrhythmias are not uncommon and usually are well tolerated by patients.12,13,18 Mechanical irritation of the septum by the inflow cannula may occur during hypovolemia, triggering ventricular tachycardia or ectopy.10 Many patients
3
also present with transvenous and newer subcutaneous implantable cardioverter-defibrillators that impose specific considerations.13 Inappropriate implantable cardioverter-defibrillator shock therapy may trigger profound cardiogenic shock.1,19 Thorough perioperative co-management of these patients by cardiologists, surgeons, a cardiovascular implantable electronic device team, and anesthesiologists provides optimal safety, in accordance with the guidelines listed by the Heart Rhythm Society/American Society of Anesthesiologists Expert Consensus Statement on the Perioperative Management of Patients with Implantable Defibrillators, Pacemakers, and Arrhythmia Monitors.20,21 TRAINING AND OUTCOMES
Highly specialized techniques and skills are required to handle patients with CF-LVADs during noncardiac surgery.22 As such, most centers require the help of cardiothoracic anesthesiologists in the management of these patients. A survey by Sheu et al reported that cardiothoracic anesthesiologists managed the majority of noncardiac surgeries and endoscopies in patients with CF-LVADs. Furthermore, the authors reported that LVAD-specific trained personnel such as perfusionists and nurses also played a critical role in the care of these patients.10 Another study by Stone et al reported similar findings.4 Other studies have cited cardiothoracic anesthesiologists’ involvement in 36% to 100% of noncardiac surgeries involving CFLVAD-supported patients.2,5,22 Even though these studies did
not compare the outcomes between patients cared for by cardiothoracic anesthesiologists and by general anesthesiologists, the experience acquired by cardiothoracic anesthesiologists during CF-LVAD implantation in heart failure patients may be the reason why most centers employ this approach. CONCLUSIONS
Despite the lack of prospective studies comparing outcomes in CF-LVAD patients undergoing noncardiac surgery under the guidance of a cardiothoracic anesthesiologist versus a general anesthesiologist, available evidence indicates that cardiothoracic anesthesiologists may be better suited to provide anesthetic care for CF-LVAD patients during noncardiac surgery due to the unique complications related to this group of patients. The skill set of the cardiothoracic anesthesiologist may be of value, especially during periods of hemodynamic instability, particularly when certain monitors such as TEE may provide additional guidance to patient care. It is vital that all anesthesiologists, regardless of specialty, familiarize themselves with the unique needs of CF-LVAD patients undergoing surgery. When general anesthesiologists encounter patients with CF-LVADs undergoing noncardiac surgery, CF-LVAD coordinators and perfusionists with an indepth understanding of these complex devices may be vital to the successful care of such patients.
REFERENCES 1. Bhat G, Kumar S, Aggarwal A, et al: Experience with noncardiac surgery in destination therapy left ventricular assist devices patients. ASAIO J 584:396-401, 2012 2. Barbara DW, Wetzel DR, Pulido JN, et al: The perioperative management of patients with left ventricular assist devices undergoing noncardiac surgery. Mayo Clin Proc 88:674-682, 2013 3. Stone M, Hinchey J, Sattler C, et al: Trends in the management of patients with left ventricular assist devices presenting for noncardiac surgery: A 10-year institutional experience. Semin Cardiothorac Vasc Anesth [Epub ahead of print]. 4. Stone ME, Soong W, Krol M, et al: The anesthetic considerations in patients with ventricular assist devices presenting for noncardiac surgery: A review of eight cases. Anesth Analg 95:42-49, 2002 5. Nelson EW, Heinke T, Finley A, et al: Management of LVAD patients for noncardiac surgery: A single-institution study. J Cardiothorac Vasc Anesth 29:898-900, 2015 6. Morgan JA, Paone G, Nemeh HW, et al: Noncardiac surgery in patients on long-term left ventricular assist device support. J Heart Lung Transplant 31:757-763, 2012 7. Kirklin JK, Naftel DC, Pagani FD, et al: Seventh INTERMACS annual report: 15,000 patients and counting. J Heart Lung Transplant 34:1495-1504, 2015 8. Slininger KA, Haddadin AS, Mangi AA: Perioperative management of patients with left ventricular assist devices undergoing noncardiac surgery. J Cardiothorac Vasc Anesth 27:752-759, 2013 9. Hieda M, Seguchi O, Mutara Y, et al: Acute response test to adaptive servo-ventilation, a possible modality to assessing the reversibility of pulmonary vascular resistance. J Artif Organs 18:280-283, 2015 10. Sheu R, Joshi B, High K, et al: Perioperative management of patients with left ventricular assist devices undergoing noncardiac procedures: A survey of current practices. J Cardiothorac Vasc Anesth 29:17-26, 2015
11. Roberts SM, Hovord DG, Kodavatiganti R, et al: Ventricular assist devices and non-cardiac surgery. BMC Anesthesiol 15:185, 2015 12. Hessel EA: II: Management of patients with implanted ventricular assist devices for noncardiac surgery: A clinical review. Semin Cardiothorac Vasc Anesth 18:57-70, 2014 13. El-Magharbel I: Ventricular assist devices and anesthesia. Semin Cardiothorac Vasc Anesth 9:241-249, 2005 14. Porter TR, Shillcutt SK, Adams MS, et al: Guidelines for the use of echocardiography as a monitor for therapeutic intervention in adults: A report from the American Society of Echocardiography. J Am Soc Echocardiogr 28:40-56, 2015 15. Patangi SO, George A, Pauli H, et al: Management issues during HeartWare left ventricular assist device implantation and the role of transesophageal echocardiography. Ann Card Anaesth 16:259-267, 2013 16. Ahmed M, Le H, Aranda JM Jr, et al: Elective noncardiac surgery in patients with left ventricular assist devices. J Card Surg 27: 639-642, 2012 17. Taghavi S, Jayarajan SN, Ambur V, et al: Non-cardiac surgical procedures after left ventricular assist device implantation. ASAIO J [Epub ahead of print]. 18. Yuzefpolskaya M, Uriel N, Flannery M, et al: Advanced cardiovascular life support algorithm for the management of the hospitalized unresponsive patient on continuous flow left ventricular assist device support outside the intensive care unit. Eur Heart J Acute Cardiovasc Care [Epub ahead of print] 19. Grimm JC, Magruder JT, Kemp CD, et al: Late complications following continuous-flow left ventricular assist device implantation. Front Surg 2:42, 2015 20. Essandoh M, Daoud EG: Perioperative considerations for patients with subcutaneous implantable cardioverter-defibrillators undergoing noncardiac surgery. J Cardiothorac Vasc Anesth [Epub ahead of print]
4
21. Crossley GH, Poole JE, Rozner MA, et al: The Heart Rhythm Society (HRS)/American Society of Anesthesiologists (ASA) Expert Consensus Statement on the perioperative management of patients with implantable defibrillators, pacemakers and arrhythmia monitors: Facilities and patient management this document was developed as a joint
STOICEA ET AL
project with the American Society of Anesthesiologists (ASA), and in collaboration with the American Heart Association (AHA), and the Society of Thoracic Surgeons (STS). Heart Rhythm 8:1114-1154, 2011 22. Leslie K, Merry AF: Cardiac surgery: All for one and one for all. Anesth Analg 120:504-506, 2015
Pro: Cardiothoracic Anesthesiologists Should Provide Anesthetic Care for Patients With Ventricular Assist Devices Undergoing Noncardiac Surgery Nicoleta Stoicea, MD, PhD,* Fabrizzio Sacchet-Cardozo, MD,* Nicholas Joseph,† Ahmet Kilic, MD,‡ Angela Sipes,* and Michael Essandoh, MD*
T
HE DEVELOPMENT of the left ventricular assist device (LVAD) has increased the life expectancy of patients with advanced heart failure significantly.1–3 Consequently, LVADs are being implanted at a rate of more than 2,000 devices per year in the United States, comparable to the annual number of heart transplantations performed. Due to this high rate of implantation and a 4-year survival rate, which now nears 50%, LVAD-supported patients presenting for noncardiac surgery have become increasingly common.1–6 According to the seventh report of the Interagency Registry for Mechanical Assist Circulatory Support (INTERMACS), 490% of LVAD implantations are continuous-flow (CF) devices such as the HeartMate II (St. Jude Medical, St. Paul, MN) and the Heartware HVAD (Heartware International Inc., Framingham, MA), with the HeartMate II being the most implanted LVAD, being approved for destination therapy and as a bridge to transplant.7–9 Despite the proven safety and efficacy of LVAD therapy, a significant number of LVAD-supported patients undergo noncardiac surgery because of complications associated with LVAD therapy.3–5,10 Noncardiac surgeries inclusive of hernia repairs; bowel resections; urologic procedures; and ear, nose, and throat surgeries have been reported in LVAD patients.2,8 Gastrointestinal bleeding also is a common complication associated with CF-LVAD therapy based on the need for antiplatelet and anticoagulation therapy, the high incidence of pathologic arteriovenous malformations, and von Willebrand factor conformational changes produced by continuous blood flow in the pump; as such, patients with CF-LVADs frequently require endoscopy.8,10–12 Additionally, between 2.5% and 10% of LVAD patients will experience intracranial hemorrhage secondary to anticoagulation therapy, and may require emergent craniotomies.8,12 Because of the increased risk for complications related to LVAD therapy, cardiothoracic anesthesiology services often are required when these patients present for noncardiac surgery. CONTINUOUS-FLOW LEFT VENTRICULAR ASSIST DEVICE COMPONENTS AND FUNCTIONALITY
Continuous-flow LVADs have 3 components: an inflow cannula that is implanted at the apex of the left ventricle (LV) and attaches to the pump, an axial pump (HeartMate II) or a centrifugal pump (Heartware HVAD) that unloads the LV, and an outflow graft that connects the pump to the ascending aorta.11,12
Appropriate functionality of the CF-LVAD is determined by the following LVAD parameters: pump flow, power consumption, pulsatility index, and pump speed.11 The implanting physician determines the pump speed, whereas the pump flow is derived from the power consumption of the pump.11 The pulsatility index reflects the contribution of the contractility of the native LV to cardiac output and serves as an index of LV preload and inotropy.12 Indepth knowledge of these CF-LVAD parameters is crucial during patient care and may affect hemodynamic management during noncardiac surgery. Accordingly, anesthesiologists caring for CFLVAD patients undergoing noncardiac surgery should understand the CF-LVAD parameters described above before proceeding to the operating room.3 Furthermore, considering that approximately 91% of patients with CF-LVADs who underwent noncardiac surgery had a HeartMate II, anesthesiologists should be particularly familiar with the specifications of this device.13 ANESTHETIC CONSIDERATIONS FOR NONCARDIAC SURGICAL PROCEDURES
Preoperative Assessment The delicate nature of patients with CF-LVADs presenting for noncardiac surgery necessitates a detailed preoperative assessment prior to proceeding with surgery. Interrogation of the CF-LVAD by a VAD coordinator or a perfusionist may provide the anesthesiologist with vital data regarding the functionality of the device in the prior months.11,12 Laboratory tests and imaging studies such as a chest radiograph also should be obtained, and prior echocardiograms should be reviewed to determine right ventricular function after CF-LVAD
From the Departments of *Anesthesiology; †Neuroscience; and ‡Surgery, Wexner Medical Center, The Ohio State University, Columbus, OH. Address reprint requests to Michael Essandoh, MD, Department of Anesthesiology, Division of Cardiothoracic and Vascular Anesthesiology, The Ohio State University, Wexner Medical Center, Doan Hall N 411, 410 W 10th Ave., Columbus, OH. 43210. E-mail: Michael. [email protected] © 2016 Elsevier Inc. All rights reserved. 1053-0770/2602-0034$36.00/0 http://dx.doi.org/10.1053/j.jvca.2016.06.030 Key Words: left ventricular assist device, noncardiac surgery, cardiothoracic anesthesiologists, left ventricular assist device parameters
Journal of Cardiothoracic and Vascular Anesthesia, Vol ], No ] (Month), 2016: pp ]]]–]]]
1
2
STOICEA ET AL
implantation.11 Before administering anesthesia, it is imperative that anesthesiologists managing CF-LVAD patients be familiar not only with LVAD physiology, but also the control algorithms to ensure patient safety.
because of the complexity of CF-LVAD physiology.11,15 To ensure timely therapy for hypotension, inotropic and vasopressor medications should be available readily during induction. SUCTION EVENTS
INTRAOPERATIVE CONSIDERATIONS
Monitoring Hemodynamic monitoring in patients with CF-LVADs remains a challenge because of the nonpulsatile nature of these devices. The anesthesiologist’s ability to monitor patient hemodynamics by automated oscillometric blood pressure (BP) and pulse oximetry may be impaired because of decreased arterial flow pulsatility.2,3,5,10-12 Accordingly, invasive BP monitoring is utilized in a majority of cases.11 In a survey by Sheu et al, 83.8% of respondents from institutions with small LVAD patient populations and 65.8% from institutions with large LVAD patient populations confirmed the use of invasive monitoring in addition to standard American Society of Anesthesiologists monitors for LVADpatient management during noncardiac surgery. For hemodynamic monitoring, arterial catheterization (71.2%), pulmonary arterial catheters (1.3%), central venous catheters (12.0%), and transesophageal echocardiography (TEE) (14.6%) were utilized in minor procedures. The study concluded that 72.5% of noncardiac surgical cases employed 1 or more methods of invasive monitoring.10 In contrast, Stone et al reported arterial line use in only 44% of cases overall, central venous catheter use in 27% of cases, pulmonary arterial catheter use in 10% of cases, and TEE utilization in 14.4% of cases.3 Moreover, 77% of reviewed cases of noncardiac procedures in LVAD patients between 2012 and 2013 did not use invasive BP monitoring.4,10 Contrasting Sheu and Stone’s studies, TEE was implemented in only 3% of patients in a case series reported by Barbara et al.2 According to Hessel et al, TEE and transthoracic echocardiography play an important role in hemodynamic evaluation and adjustment of the pump during noncardiac surgery.13 TEE provides structural and functional information pertaining to LVAD management such as right ventricular geometry and systolic function, in addition to the positions of the interventricular septum and the inflow cannula.12 These data may be essential to guide volume management and pump speed selection, and may further help avoid suction events.13,14 Monitoring LVAD parameters, such as flow, pulsatility index, and LVAD speed, is mandatory.1,2 With regard to the monitoring of oxygenation, near-infrared cerebral spectroscopy, as a substitute for pulse oximetry, has found particular use in the anesthetic management of CFLVAD patients, as this technique does not rely upon pulsatile flow.2,3,10,13 INDUCTION AND MAINTENANCE OF GENERAL ANESTHESIA
The majority of surgeries in CF-LVAD patients are performed with general anesthesia or monitored anesthesia care.15 Regional anesthesia is employed rarely, considering the need for chronic anticoagulation therapy and the high incidence of hepatic dysfunction in the CF-LVAD population.8,13 Induction and maintenance of general anesthesia can be challenging
Understanding the physiology of CF-LVADs is important for the provision of anesthetic care to this population.15 Hemodynamic management of CF-LVAD patients involves accounting for conditions that may impart significant strain on the right ventricle, such as hypoxia, hypercarbia, circulatory overload, lung hyperinflation, light anesthetic depth, and acidosis.12 These complications should be avoided as they may lead to increased risk of right ventricular failure and low CF-LVAD flows. LV preload maintenance also is essential to establishing adequate CF-LVAD flows, and may help in preventing suction events and associated ventricular arrhythmias.2,12,15 In addition to blood and fluid loss, positive-pressure ventilation, reverse Trendelenburg positioning, lateral decubitus positioning, and pneumoperitoneum may impair venous return, thereby triggering suction events.11 Awareness of increased risks for CF-LVAD patients and associated complications during hemodynamic management is recommended, and caution is advised.13,15,16 CARDIOVASCULAR DRUG SUPPORT
Systemic vascular resistance must be managed to ensure an adequate end-organ perfusion.5 Up to 72% of CF-LVAD patients required cardiovascular drug support, implying a need for trained provider involvement in inotrope and vasopressor support, and general LVAD patient management.2,13 It is recommended that mean arterial pressure (MAP) be maintained between 70 mmHg and 80 mmHg in CF-LVAD patients, for which trained provider involvement is especially advised by many authors.13 Higher MAPs, however, can reduce CFLVAD flows and promote pump stasis, a known risk factor for pump thrombosis. Considering that anticoagulation and antiplatelet therapy may be interrupted for surgery, optimal MAPs should be maintained to avoid pump thrombosis. BLOOD REQUIREMENTS AND ANTICOAGULATION
Development of complex coagulopathy during CF-LVAD therapy increases the need for blood-product transfusion during noncardiac surgery.1,2 Blood transfusions may increase pulmonary vascular resistance, reducing LV preload and CFLVAD flow.1 Reversal of anticoagulation may be considered depending on the patient’s bleeding risk and thrombotic history and the surgical procedure performed.2,13 The model of CFLVAD implanted also may dictate the level of anticoagulation, as some studies suggest the HeartMate II requires lower levels of anticoagulation than other CF-LVAD devices.12,13 However, specific guidelines do not exist, and high rates of bleeding complications have been reported during noncardiac surgery, reaching a 44% incidence in Taghavi et al’s study.17 ADVANCED CARDIOVASCULAR LIFE SUPPORT
Ventricular arrhythmias are not uncommon and usually are well tolerated by patients.12,13,18 Mechanical irritation of the septum by the inflow cannula may occur during hypovolemia, triggering ventricular tachycardia or ectopy.10 Many patients
3
also present with transvenous and newer subcutaneous implantable cardioverter-defibrillators that impose specific considerations.13 Inappropriate implantable cardioverter-defibrillator shock therapy may trigger profound cardiogenic shock.1,19 Thorough perioperative co-management of these patients by cardiologists, surgeons, a cardiovascular implantable electronic device team, and anesthesiologists provides optimal safety, in accordance with the guidelines listed by the Heart Rhythm Society/American Society of Anesthesiologists Expert Consensus Statement on the Perioperative Management of Patients with Implantable Defibrillators, Pacemakers, and Arrhythmia Monitors.20,21 TRAINING AND OUTCOMES
Highly specialized techniques and skills are required to handle patients with CF-LVADs during noncardiac surgery.22 As such, most centers require the help of cardiothoracic anesthesiologists in the management of these patients. A survey by Sheu et al reported that cardiothoracic anesthesiologists managed the majority of noncardiac surgeries and endoscopies in patients with CF-LVADs. Furthermore, the authors reported that LVAD-specific trained personnel such as perfusionists and nurses also played a critical role in the care of these patients.10 Another study by Stone et al reported similar findings.4 Other studies have cited cardiothoracic anesthesiologists’ involvement in 36% to 100% of noncardiac surgeries involving CFLVAD-supported patients.2,5,22 Even though these studies did
not compare the outcomes between patients cared for by cardiothoracic anesthesiologists and by general anesthesiologists, the experience acquired by cardiothoracic anesthesiologists during CF-LVAD implantation in heart failure patients may be the reason why most centers employ this approach. CONCLUSIONS
Despite the lack of prospective studies comparing outcomes in CF-LVAD patients undergoing noncardiac surgery under the guidance of a cardiothoracic anesthesiologist versus a general anesthesiologist, available evidence indicates that cardiothoracic anesthesiologists may be better suited to provide anesthetic care for CF-LVAD patients during noncardiac surgery due to the unique complications related to this group of patients. The skill set of the cardiothoracic anesthesiologist may be of value, especially during periods of hemodynamic instability, particularly when certain monitors such as TEE may provide additional guidance to patient care. It is vital that all anesthesiologists, regardless of specialty, familiarize themselves with the unique needs of CF-LVAD patients undergoing surgery. When general anesthesiologists encounter patients with CF-LVADs undergoing noncardiac surgery, CF-LVAD coordinators and perfusionists with an indepth understanding of these complex devices may be vital to the successful care of such patients.
REFERENCES 1. Bhat G, Kumar S, Aggarwal A, et al: Experience with noncardiac surgery in destination therapy left ventricular assist devices patients. ASAIO J 584:396-401, 2012 2. Barbara DW, Wetzel DR, Pulido JN, et al: The perioperative management of patients with left ventricular assist devices undergoing noncardiac surgery. Mayo Clin Proc 88:674-682, 2013 3. Stone M, Hinchey J, Sattler C, et al: Trends in the management of patients with left ventricular assist devices presenting for noncardiac surgery: A 10-year institutional experience. Semin Cardiothorac Vasc Anesth [Epub ahead of print]. 4. Stone ME, Soong W, Krol M, et al: The anesthetic considerations in patients with ventricular assist devices presenting for noncardiac surgery: A review of eight cases. Anesth Analg 95:42-49, 2002 5. Nelson EW, Heinke T, Finley A, et al: Management of LVAD patients for noncardiac surgery: A single-institution study. J Cardiothorac Vasc Anesth 29:898-900, 2015 6. Morgan JA, Paone G, Nemeh HW, et al: Noncardiac surgery in patients on long-term left ventricular assist device support. J Heart Lung Transplant 31:757-763, 2012 7. Kirklin JK, Naftel DC, Pagani FD, et al: Seventh INTERMACS annual report: 15,000 patients and counting. J Heart Lung Transplant 34:1495-1504, 2015 8. Slininger KA, Haddadin AS, Mangi AA: Perioperative management of patients with left ventricular assist devices undergoing noncardiac surgery. J Cardiothorac Vasc Anesth 27:752-759, 2013 9. Hieda M, Seguchi O, Mutara Y, et al: Acute response test to adaptive servo-ventilation, a possible modality to assessing the reversibility of pulmonary vascular resistance. J Artif Organs 18:280-283, 2015 10. Sheu R, Joshi B, High K, et al: Perioperative management of patients with left ventricular assist devices undergoing noncardiac procedures: A survey of current practices. J Cardiothorac Vasc Anesth 29:17-26, 2015
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