- Email: [email protected]
Computerized Euglycemia in Cardiovascular and Thoracic Surgery
1048
CORRESPONDENCE
References 1. Gomes WJ. Hybrid coronary artery revascularization: an evidence-based analysis (letter). Ann Thorac Surg 2009;88: 1047. 2. Holzhey DM, Jacobs S, Mochalski M, et al. Minimally invasive hybrid coronary artery revascularization. Ann Thorac Surg 2008;86:1856 – 60.
Acute Profound Thrombocytopenia After Treatment With Tirofiban and Off-Pump Coronary Artery Bypass Grafting: Is There a Paradox? To the Editor: I read with interest the case report by Beiras-Fernandez and colleagues [1]. This case report reveals one more time how challenging it is to operate on patients with acute coronary syndrome and IIB–IIIa receptor antagonist infusion, such as tirofiban hydrochloride, because of the risk of profound bleeding complications and thrombocytopenia. We studied the effects of this drug on patients undergoing coronary artery bypass grafting with extracorporeal circulation [2]. Paradoxically, in our study, the infusion of tirofiban hydrochloride immediately before surgery did not adversely affect clinical outcome and did not have any deleterious effect on postoperative bleeding, maintaining hemoglobin, and platelet counts at stable levels. The reason is not yet clear, but tirofiban probably provides a sort of “platelet anestesia” during cardiopulmonary bypass [3]; in fact, this short-acting drug can be safely metabolized during extracorporeal circulation, “protecting” platelets that can act “normally” at the end of the operation. Tirofiban hydrochloride is per se’ a powerful and strong bleeding and antiplatelet drug, and the risk related to these properties are high during an off-pump procedure, because this is really performed during the period of action of the drug (3 hours). Stopping the infusion of this molecule at the beginning of the operation exposes these patients to all these risks. In conclusion, it seems, in my opinion, that Tirofiban hydrochloride has paradoxically “protective effects” during extracorporeal circulation, but during an off-pump coronary artery bypass grafting, the risks of bleeding must be heavily considered, and the infusion of the drug probably must be stopped earlier.
MISCELLANEOUS
Federico Bizzarri, MD Giacomo Frati, MD Cardiac Surgery Unit-Polo Pontino Department of Heart and Great Vessels “Attilio Reale” University of Rome “Sapienza” Via F. Faggiana 34 Latina, 04100 Italy e-mail: [email protected]
References 1. Beiras-Fernandez A, Kowert A, Jiru P, et al. Acute profound thrombocytopenia after treatment with tirofiban and offpump coronary artery bypass grafting. Ann Thorac Surg 2009, 87:629 –31. 2. Bizzarri F, Scolletta S, Tucci E, et al. Perioperative use of tirofiban hydrocloride (Aggrastat) does not increase surgical bleeding after emergency or urgent coronary artery bypass grafting. J Thorac Cardiovasc Surg 2001;122:1181–5. © 2009 by The Society of Thoracic Surgeons Published by Elsevier Inc
Ann Thorac Surg 2009;88:1047–52
3. Hiramatsu Y, Gikakis N, Anderson HL 3rd, et al. Tirofiban provides “platelets anestesia” during cardiopulmonary bypass in baboons. J Thorac Cardiovasc Surg 1997;113:182–93.
Reply To the Editor: We appreciate very much the interest expressed by Bizzarri and Frati [1] regarding our brief communication about a case of profound thrombocytopenia after off-pump coronary artery bypass grafting and treatment with tirofiban [2]. We agree with the authors that preoperative treatment with glycoprotein IIb/IIIa antagonists may be challenging due to postoperative bleeding complications. In fact, the aim of our report was to underline the risk of thrombocytopenia after infusion of these molecules, as well as to suggest management strategies to deal with this complication. Bizzarri and Frati [1] raised an important issue in the preoperative use of tirofiban for patients undergoing coronary artery bypass grafting (ie, the use of extracorporeal circulation). In a previous work, they showed no adverse clinical effects of tirofiban in patients undergoing on-pump coronary artery bypass grafting [3]. Although the use of cardiopulmonary bypass might reduce the effect of tirofiban through conformational changes of the thrombocytes, or through direct filtration of these molecules, it is not clear whether tirofiban may exert a protective effect on platelets. In our opinion, more data regarding the use of tirofiban in patients undergoing off-pump coronary surgery should be collected to answer the paradoxical question of Bizzarri and Frati [1]. However, we agree with the authors that the administration of tirofiban should be stopped early and preoperatively to reduce the bleeding risks. Further studies are needed to investigate the association between profound thrombocytopenia and GP IIb/IIIa antagonists. Andres Beiras-Fernandez, MD Marion Weis, MD Michael Schmoeckel, MD Department of Cardiac Surgery University Hospital Grosshadern Marchioninistrasse 15 Munich, 81377 Germany e-mail: [email protected]
References 1. Bizzarri F, Frati G. Acute profound thrombocytopenia after treatment with tirofiban and off-pump coronary artery bypass grafting: is there a paradox? (letter) Ann Thorac Surg 2009,88: 1048. 2. Beiras-Fernandez A, Kowert A, Jiru P, et al. Acute profound thrombocytopenia after treatment with tirofiban and offpump coronary artery bypass grafting. Ann Thorac Surg 2009,87:629 –31. 3. Bizzarri F, Scolletta S, Tucci E, et al. Perioperative use of tirofiban hydrocloride (Aggrastat) does not increase surgical bleeding after emergency or urgent coronary artery bypass grafting. J Thorac Cardiovasc Surg 2001;122:1181–5.
Computerized Euglycemia in Cardiovascular and Thoracic Surgery To the Editor: The EndoTool Glucose Management System (EGMS) (Hospira Inc, Lake Forest, IL) warrants consideration, despite exclusion 0003-4975/09/$36.00
Ann Thorac Surg 2009;88:1047–52
Kevin W. Lobdell, MD Adult and Pediatric Cardiovascular Critical Care Carolinas Heart and Vascular Institute PO Box 32861 Charlotte, NC 28232 e-mail: [email protected]
References 1. Lazar HL, McDonnell M, Chipkin SR, et al. The Society of Thoracic Surgeons practice guideline series: blood glucose management during adult cardiac surgery. Ann Thorac Surg 2009;87:663–9. 2. Stamou SC, Camp SL, Stiegel RM, et al. Quality improvement program decreases mortality after cardiac surgery. J Thorac Cardiovasc Surg 2008;136:494 –9. 3. Stamou SC, Camp SL, Reames MR, et al. Continuous quality improvement program and major morbidity after cardiac surgery. Am J Card 2008;102:772–7. 4. Lobdell KW, Burgess WP, Geller HS. EndoTool software for glucose control in thoracic surgery patients. ATS 2007 International Conference, San Francisco, CA. Abstract A596.
Reply To the Editor: In our guidelines [1], we have described a few protocols that are readily available for clinical use and the target glucose values that can be achieved. Our list was assembled prior to the Food and Drug Administration approval for the Endo Tool Glucose Management System reported by Lobdell and coworkers [2]. Nevertheless, we wish to congratulate them on their fine results and look forward to hearing more about their innovative method for achieving glycemic control. Harold L. Lazar, MD Department of Cardiothoracic Surgery Boston Medical Center 88 E Newton St, B404 Boston, MA 02118 e-mail: [email protected]
References 1. Lazar HL, McDonnell M, Chipkin SR, et al. The Society of Thoracic Surgeons practice guideline series: blood glucose © 2009 by The Society of Thoracic Surgeons Published by Elsevier Inc
1049
management during adult cardiac surgery. Ann Thorac Surg 2009;87:663–9. 2. Lobdell KW. Computerized euglycemia in cardiovascular and thoracic surgery (letter). Ann Thorac Surg 2009;88:1048 –9.
Avoiding Prosthesis-Patient Mismatch in the Elderly: Options Other Than Mechanical Prostheses To the Editor: We read with interest the article by Vicchio and colleagues [1] evaluating the impact of prosthesis-patient mismatch (PPM) on the outcomes and quality of life of elderly patients with small sized aortic mechanical prostheses. In our view, tissue valves are the preferred prostheses for elderly patients undergoing valve replacement, and we were surprised to read that the authors solely implanted mechanical prostheses in a cohort of patients over 70 years of age. Several groups including our own have reported outstanding results with the use of contemporary bioprostheses [2], especially in elderly cohorts [3]. Nevertheless, Vicchio and colleagues [1] documented excellent outcomes in their series, with 10-year rates of freedom from bleeding and thromboembolism of 96.9% and 99%, respectively. In their article, Vicchio and colleagues [1] defined PPM using the effective orifice area (EOA) measured at the “routine 1-year postoperative echocardiographic evaluation,” indexed for body surface area. A controversial topic, PPM has been described using several methods in the literature. In our previous work, we used fixed values of in vivo EOAs (also known as projected EOAs) for each prosthesis type and size from literature sources of patients with normally functioning prostheses [4]. This technique avoids the challenges in accurately measuring the left ventricular outflow diameter after surgery due to prosthetic valve reverberations, as well as the presence of large localized transprosthetic gradients that may result in large discrepancies between Doppler echocardiography and “actual” EOA measurements [5, 6]. Did the authors consider applying alternative methodology by using projected EOAs? Moreover, we have previously shown that patients with preoperative left ventricular dysfunction are more susceptible to the deleterious effects of postoperative PPM [7, 8]. We would be interested to learn from the authors whether they explored this question with their impressive quality of life dataset. Most importantly, we were surprised to read the accompanying Invited Commentary written by Banbury [9] that followed Vicchio and colleagues’ [1] article. Banbury [9] stated that it is an “undeniable fact” that the aortic root enlargement procedure has a “penalty of a higher perioperative mortality rate.” We take exception to this opinion, with several recent series reporting no increase in perioperative mortality rate among patients undergoing aortic root enlargement at the time of aortic valve replacement [10, 11]. Aortic root enlargement is a safe and effective procedure that helps avoid postoperative PPM. In our view, aortic root enlargement and the insertion of a bioprosthesis constitutes a judicious alternative, as compared with the insertion of a mechanical valve with the attendant anticoagulation in an elderly patient with a small aortic root undergoing aortic valve replacement. Alexander Kulik, MD, MPH Nicholas T. Kouchoukos, MD Division of Cardiovascular and Thoracic Surgery Missouri Baptist Medical Center St. Louis, MO 63131 0003-4975/09/$36.00
MISCELLANEOUS
from the report by The Society of Thoracic Surgeons Workforce by Lazar and colleagues [1] (list of published and commercially available variable rate insulin infusion protocols). The EGMS uses feedback control mathematics, which has been routinely used at the Carolinas Heart and Vascular Institute (approved by the Food and Drug Administration on 20 June 2006 and presently commercially available from Hospira, Inc) in over 4,000 adult cardiovascular surgery patients, and it is a cornerstone of our quality improvement program [2, 3] which has significantly mitigated the risk of death and complications. The algorithm used in the EGMS controls a nonlinear insulin-dosing relationship for each patient based on the response of the patient’s trend of up to the last four insulin and glucose responses, resulting in safe, prompt euglycemia in both diabetics and nondiabetics. In our cardiovascular recovery unit, the mean glucose of all glucose readings is 117 mg/dL, with an incidence of profound hypoglycemia (ⱕ40 mg/dL) of less than 0.1% of readings and less than 2% of patients [4]. The majority of hypoglycemia relates to tardy point-of-care glucose testing.
CORRESPONDENCE
CORRESPONDENCE
References 1. Gomes WJ. Hybrid coronary artery revascularization: an evidence-based analysis (letter). Ann Thorac Surg 2009;88: 1047. 2. Holzhey DM, Jacobs S, Mochalski M, et al. Minimally invasive hybrid coronary artery revascularization. Ann Thorac Surg 2008;86:1856 – 60.
Acute Profound Thrombocytopenia After Treatment With Tirofiban and Off-Pump Coronary Artery Bypass Grafting: Is There a Paradox? To the Editor: I read with interest the case report by Beiras-Fernandez and colleagues [1]. This case report reveals one more time how challenging it is to operate on patients with acute coronary syndrome and IIB–IIIa receptor antagonist infusion, such as tirofiban hydrochloride, because of the risk of profound bleeding complications and thrombocytopenia. We studied the effects of this drug on patients undergoing coronary artery bypass grafting with extracorporeal circulation [2]. Paradoxically, in our study, the infusion of tirofiban hydrochloride immediately before surgery did not adversely affect clinical outcome and did not have any deleterious effect on postoperative bleeding, maintaining hemoglobin, and platelet counts at stable levels. The reason is not yet clear, but tirofiban probably provides a sort of “platelet anestesia” during cardiopulmonary bypass [3]; in fact, this short-acting drug can be safely metabolized during extracorporeal circulation, “protecting” platelets that can act “normally” at the end of the operation. Tirofiban hydrochloride is per se’ a powerful and strong bleeding and antiplatelet drug, and the risk related to these properties are high during an off-pump procedure, because this is really performed during the period of action of the drug (3 hours). Stopping the infusion of this molecule at the beginning of the operation exposes these patients to all these risks. In conclusion, it seems, in my opinion, that Tirofiban hydrochloride has paradoxically “protective effects” during extracorporeal circulation, but during an off-pump coronary artery bypass grafting, the risks of bleeding must be heavily considered, and the infusion of the drug probably must be stopped earlier.
MISCELLANEOUS
Federico Bizzarri, MD Giacomo Frati, MD Cardiac Surgery Unit-Polo Pontino Department of Heart and Great Vessels “Attilio Reale” University of Rome “Sapienza” Via F. Faggiana 34 Latina, 04100 Italy e-mail: [email protected]
References 1. Beiras-Fernandez A, Kowert A, Jiru P, et al. Acute profound thrombocytopenia after treatment with tirofiban and offpump coronary artery bypass grafting. Ann Thorac Surg 2009, 87:629 –31. 2. Bizzarri F, Scolletta S, Tucci E, et al. Perioperative use of tirofiban hydrocloride (Aggrastat) does not increase surgical bleeding after emergency or urgent coronary artery bypass grafting. J Thorac Cardiovasc Surg 2001;122:1181–5. © 2009 by The Society of Thoracic Surgeons Published by Elsevier Inc
Ann Thorac Surg 2009;88:1047–52
3. Hiramatsu Y, Gikakis N, Anderson HL 3rd, et al. Tirofiban provides “platelets anestesia” during cardiopulmonary bypass in baboons. J Thorac Cardiovasc Surg 1997;113:182–93.
Reply To the Editor: We appreciate very much the interest expressed by Bizzarri and Frati [1] regarding our brief communication about a case of profound thrombocytopenia after off-pump coronary artery bypass grafting and treatment with tirofiban [2]. We agree with the authors that preoperative treatment with glycoprotein IIb/IIIa antagonists may be challenging due to postoperative bleeding complications. In fact, the aim of our report was to underline the risk of thrombocytopenia after infusion of these molecules, as well as to suggest management strategies to deal with this complication. Bizzarri and Frati [1] raised an important issue in the preoperative use of tirofiban for patients undergoing coronary artery bypass grafting (ie, the use of extracorporeal circulation). In a previous work, they showed no adverse clinical effects of tirofiban in patients undergoing on-pump coronary artery bypass grafting [3]. Although the use of cardiopulmonary bypass might reduce the effect of tirofiban through conformational changes of the thrombocytes, or through direct filtration of these molecules, it is not clear whether tirofiban may exert a protective effect on platelets. In our opinion, more data regarding the use of tirofiban in patients undergoing off-pump coronary surgery should be collected to answer the paradoxical question of Bizzarri and Frati [1]. However, we agree with the authors that the administration of tirofiban should be stopped early and preoperatively to reduce the bleeding risks. Further studies are needed to investigate the association between profound thrombocytopenia and GP IIb/IIIa antagonists. Andres Beiras-Fernandez, MD Marion Weis, MD Michael Schmoeckel, MD Department of Cardiac Surgery University Hospital Grosshadern Marchioninistrasse 15 Munich, 81377 Germany e-mail: [email protected]
References 1. Bizzarri F, Frati G. Acute profound thrombocytopenia after treatment with tirofiban and off-pump coronary artery bypass grafting: is there a paradox? (letter) Ann Thorac Surg 2009,88: 1048. 2. Beiras-Fernandez A, Kowert A, Jiru P, et al. Acute profound thrombocytopenia after treatment with tirofiban and offpump coronary artery bypass grafting. Ann Thorac Surg 2009,87:629 –31. 3. Bizzarri F, Scolletta S, Tucci E, et al. Perioperative use of tirofiban hydrocloride (Aggrastat) does not increase surgical bleeding after emergency or urgent coronary artery bypass grafting. J Thorac Cardiovasc Surg 2001;122:1181–5.
Computerized Euglycemia in Cardiovascular and Thoracic Surgery To the Editor: The EndoTool Glucose Management System (EGMS) (Hospira Inc, Lake Forest, IL) warrants consideration, despite exclusion 0003-4975/09/$36.00
Ann Thorac Surg 2009;88:1047–52
Kevin W. Lobdell, MD Adult and Pediatric Cardiovascular Critical Care Carolinas Heart and Vascular Institute PO Box 32861 Charlotte, NC 28232 e-mail: [email protected]
References 1. Lazar HL, McDonnell M, Chipkin SR, et al. The Society of Thoracic Surgeons practice guideline series: blood glucose management during adult cardiac surgery. Ann Thorac Surg 2009;87:663–9. 2. Stamou SC, Camp SL, Stiegel RM, et al. Quality improvement program decreases mortality after cardiac surgery. J Thorac Cardiovasc Surg 2008;136:494 –9. 3. Stamou SC, Camp SL, Reames MR, et al. Continuous quality improvement program and major morbidity after cardiac surgery. Am J Card 2008;102:772–7. 4. Lobdell KW, Burgess WP, Geller HS. EndoTool software for glucose control in thoracic surgery patients. ATS 2007 International Conference, San Francisco, CA. Abstract A596.
Reply To the Editor: In our guidelines [1], we have described a few protocols that are readily available for clinical use and the target glucose values that can be achieved. Our list was assembled prior to the Food and Drug Administration approval for the Endo Tool Glucose Management System reported by Lobdell and coworkers [2]. Nevertheless, we wish to congratulate them on their fine results and look forward to hearing more about their innovative method for achieving glycemic control. Harold L. Lazar, MD Department of Cardiothoracic Surgery Boston Medical Center 88 E Newton St, B404 Boston, MA 02118 e-mail: [email protected]
References 1. Lazar HL, McDonnell M, Chipkin SR, et al. The Society of Thoracic Surgeons practice guideline series: blood glucose © 2009 by The Society of Thoracic Surgeons Published by Elsevier Inc
1049
management during adult cardiac surgery. Ann Thorac Surg 2009;87:663–9. 2. Lobdell KW. Computerized euglycemia in cardiovascular and thoracic surgery (letter). Ann Thorac Surg 2009;88:1048 –9.
Avoiding Prosthesis-Patient Mismatch in the Elderly: Options Other Than Mechanical Prostheses To the Editor: We read with interest the article by Vicchio and colleagues [1] evaluating the impact of prosthesis-patient mismatch (PPM) on the outcomes and quality of life of elderly patients with small sized aortic mechanical prostheses. In our view, tissue valves are the preferred prostheses for elderly patients undergoing valve replacement, and we were surprised to read that the authors solely implanted mechanical prostheses in a cohort of patients over 70 years of age. Several groups including our own have reported outstanding results with the use of contemporary bioprostheses [2], especially in elderly cohorts [3]. Nevertheless, Vicchio and colleagues [1] documented excellent outcomes in their series, with 10-year rates of freedom from bleeding and thromboembolism of 96.9% and 99%, respectively. In their article, Vicchio and colleagues [1] defined PPM using the effective orifice area (EOA) measured at the “routine 1-year postoperative echocardiographic evaluation,” indexed for body surface area. A controversial topic, PPM has been described using several methods in the literature. In our previous work, we used fixed values of in vivo EOAs (also known as projected EOAs) for each prosthesis type and size from literature sources of patients with normally functioning prostheses [4]. This technique avoids the challenges in accurately measuring the left ventricular outflow diameter after surgery due to prosthetic valve reverberations, as well as the presence of large localized transprosthetic gradients that may result in large discrepancies between Doppler echocardiography and “actual” EOA measurements [5, 6]. Did the authors consider applying alternative methodology by using projected EOAs? Moreover, we have previously shown that patients with preoperative left ventricular dysfunction are more susceptible to the deleterious effects of postoperative PPM [7, 8]. We would be interested to learn from the authors whether they explored this question with their impressive quality of life dataset. Most importantly, we were surprised to read the accompanying Invited Commentary written by Banbury [9] that followed Vicchio and colleagues’ [1] article. Banbury [9] stated that it is an “undeniable fact” that the aortic root enlargement procedure has a “penalty of a higher perioperative mortality rate.” We take exception to this opinion, with several recent series reporting no increase in perioperative mortality rate among patients undergoing aortic root enlargement at the time of aortic valve replacement [10, 11]. Aortic root enlargement is a safe and effective procedure that helps avoid postoperative PPM. In our view, aortic root enlargement and the insertion of a bioprosthesis constitutes a judicious alternative, as compared with the insertion of a mechanical valve with the attendant anticoagulation in an elderly patient with a small aortic root undergoing aortic valve replacement. Alexander Kulik, MD, MPH Nicholas T. Kouchoukos, MD Division of Cardiovascular and Thoracic Surgery Missouri Baptist Medical Center St. Louis, MO 63131 0003-4975/09/$36.00
MISCELLANEOUS
from the report by The Society of Thoracic Surgeons Workforce by Lazar and colleagues [1] (list of published and commercially available variable rate insulin infusion protocols). The EGMS uses feedback control mathematics, which has been routinely used at the Carolinas Heart and Vascular Institute (approved by the Food and Drug Administration on 20 June 2006 and presently commercially available from Hospira, Inc) in over 4,000 adult cardiovascular surgery patients, and it is a cornerstone of our quality improvement program [2, 3] which has significantly mitigated the risk of death and complications. The algorithm used in the EGMS controls a nonlinear insulin-dosing relationship for each patient based on the response of the patient’s trend of up to the last four insulin and glucose responses, resulting in safe, prompt euglycemia in both diabetics and nondiabetics. In our cardiovascular recovery unit, the mean glucose of all glucose readings is 117 mg/dL, with an incidence of profound hypoglycemia (ⱕ40 mg/dL) of less than 0.1% of readings and less than 2% of patients [4]. The majority of hypoglycemia relates to tardy point-of-care glucose testing.
CORRESPONDENCE