Online Letters to the Editor
Nevertheless, the study exhibits several weaknesses, which in our eyes do not support the final statement and are not compatible with our findings in the daily life and with those that have partly been published (3): 1) Inclusion criteria for the study were patients undergoing myocardial revascularization with or without associated procedures with a preoperative ejection fraction of less than 35%. Sixty percent of patients in each group underwent combined procedures that were not further specified. Whether this was valve surgery, surgery of the aorta, or even left ventricular (LV) reduction surgery was not reported. Therefore, the risk of comparing two inhomogeneous groups is likely to occur. Especially, operations targeting reshaping of the LV of ischemic patients have been associated with very poor surgical outcome and have been abandoned in most cardiac surgical units. 2) The logistic Euroscore in general overestimates surgical risk, and therefore, it has been revised in its second version, Euroscore II. Nevertheless, operative mortality, especially in the control group, even exceeded this overestimation, which should have been an alarming sign. Although statistically not significant, there is a clear trend toward more mortality in the control group (14% vs 7.3%), which does not support the final statement. 3) IABP insertion was performed in the operating room shortly after induction of anesthesia. As shown by Christenson et al (4), a 2-hour preoperative support is early enough. Trimming this period even further down might not have the same effect. Whether an earlier insertion of the IABP would have had a beneficial effect in this study remains speculative, but in our opinion, this would have been likely to occur. We do, in fact, insert the IABP the evening before the surgical intervention, thereby providing IABP support for at least 10 hours. 4) The indication of surgical revision in the IABP group is 11%, which is exceptionally and unacceptably high and might have contributed to the bad outcomes in this patient group. Patients with postoperative bleeding are prone to (hidden) tamponade and hypovolemia with all negative consequences related to impaired cardiac output. Prevention of this complication is even more crucial in high-risk patients with poor cardiac function. 5) Possible vascular complications after IABP placement are well known, and they are most commonly related to balloon catheter insertion and positioning (e.g., arterial lumen narrowing and limb ischemia). Given the high prevalence of patients with diffuse vascular disease admitted to cardiac surgery departments, it is surprising that peripheral arterial disease or abdominal aortic aneurysm was not reported among the patients with atherosclerosis included in the study. In our institution, we routinely insert the IABP catheter in a sheathless fashion to potentially reduce ischemic vascular complications. From the article, it is not seeable whether this was the case in the study population. Because the IABP is not an active blood pumping device and cardiac performance is improved by indirect means, there are indeed limits to IABP therapy. In conclusion, we have the impression that this patient cohort exceeded those limits and might have even had an indication for an active pump to prevent perioperative low cardiac output syndrome to reach better clinical outcomes. We therefore do not agree to the conclusions of the Critical Care Medicine
article, which in our eyes are misleading. Our considerations aim to keep the debate alive on an increasingly relevant issue in cardiac surgery, given the growing number of patients with poor LV function who will need some sort of support, be it mechanically or pharmacologically to survive the surgical procedure per se. The authors have disclosed that they do not have any potential conflicts of interest. Steffen Pfeiffer, MD, Giuseppe Santarpino, MD, Joachim Sirch, MD, Theodor Fischlein, MD, Ferdinand Vogt, MD, Department of Cardiac Surgery, Cardiovascular Center, Klinikum Nürnberg–Paracelsus Medical University, Nuremberg, Germany
REFERENCES
1. Ranucci M, Castelvecchio S, Biondi A, et al; Surgical and Clinical Outcome Research (SCORE) Group: A Randomized Controlled Trial of Preoperative Intra-Aortic Balloon Pump in Coronary Patients With Poor Left Ventricular Function Undergoing Coronary Artery Bypass Surgery. Crit Care Med 2013; 41:2476–2483 2. Džavík V: Routine intra-aortic balloon pump support in high-risk cardiac surgery patients: Is it time to throw away the pump? Crit Care Med 2013; 41:2642–2644 3. Nabawi F, Santarpino G, Pfeiffer S, et al: Beneficial effect of preoperative intraaortic balloon pumping in patients with low ejection fraction undergoing coronarx artery bypass grafting. Thorac Cardiovasc Surg 2012; 60:PP56 4. Christenson JT, Simonet F, Badel P, et al: Optimal timing of preoperative intraaortic balloon pump support in high-risk coronary patients. Ann Thorac Surg 1999; 68:934–939 DOI: 10.1097/CCM.0000000000000557
The authors reply:
W
e thank Pfeiffer et al (1) for their letter commenting on our study (2) on intra-aortic balloon pump (IABP) in elective high-risk patients undergoing coronary surgery. They raised important issues that we are happy to discuss. 1) There were exactly 33 combined procedures in each group, including mitral valve surgery (14 control group, 19 IABP group), aortic valve replacement (control 3, IABP 4), and surgical ventricular reshaping (control 24, IABP 21). There is no significant difference between groups with respect to surgery, and we can therefore exclude inhomogeneity. Additionally, we would like to point out that many patients received surgical ventricular reshaping, but that the concept expressed by the authors (a procedure with “very poor surgical outcome”) is not supported by the existing evidence. The only randomized controlled trial of surgical ventricular reshaping versus coronary surgery alone (3) ended up with no differences in outcome. 2) It is true that the logistic European system for cardiac operative risk evaluation (EuroSCORE) overestimates the mortality risk. However, in this patient population, it is actually the opposite. The logistic EuroSCORE does not consider very low values of left ventricular ejection fraction and is therefore inappropriate in our patient population, where we had 26.4% of the patients with an ejection fraction less than or equal to 0.25 and 8.2% of the patients with an ejection fraction www.ccmjournal.org
e729
Online Letters to the Editor
less than or equal to 0.20. The age, creatinine, and ejection fraction score (4), which includes the ejection fraction as a continuous variable, provided a mortality risk of about 10%, perfectly in line with the overall mortality of our study. 3) Of course, we cannot exclude that an earlier implantation of the IABP may induce different effects. We understand that this is the usual practice in the authors’ hospital, but we are not aware of any recent study demonstrating that this strategy is effective in hemodynamically stable patients. 4) The authors erroneously ascribe all the surgical revisions to bleeding problems. Actually, we had only five surgical revisions (4.5%) due to bleeding. The other three cases were one laparotomy for suspect mesenteric infarction, one repair of IABP-induced vascular lesion, and one removal of extracorporeal oxygenation circuit. 5) IABP was inserted in a sheathless fashion in our study too. Major vascular complications were detected in one case only. In conclusion, we remain convinced of the possible benefits of IABP therapy in hemodynamically unstable cardiac surgery patients, but we have definitely abandoned the preoperative placement in stable coronary patients with low ejection fraction. Dr. Ranucci consulted for the Sorin Group and lectured for Medtronic, CSL Behring, Grifols SA, and Roche. The remaining authors have disclosed that they do not have any potential conflicts of interest.
e730
www.ccmjournal.org
Marco Ranucci, MD, FESC, Serenella Castelvecchio, MD, FESC, Department of Cardiothoracic–Vascular Anesthesia and Intensive Care, IRCCS Policlinico San Donato, Milan, Italy; Andrea Biondi, MD, Carlo De Vincentiis, MD, Department of Cardiac Surgery, IRCCS Policlinico San Donato, Milan, Italy; Andrea Ballotta, MD, FESC, Department of Cardiothoracic–Vascular Anesthesia and Intensive Care, IRCCS Policlinico San Donato, Milan, Italy; Alessandro Varrica, MD, Alessandro Frigiola, MD, Lorenzo Menicanti, MD, Department of Cardiac Surgery, IRCCS Policlinico San Donato, Milan, Italy
REFERENCES
1. Pfeiffer S, Santarpino G, Sirch J, et al: Does Prophylactic Intra-Aortic Balloon Pumping Really Fail to Improve Perioperative Outcomes in Patients With Poor Left Ventricular Function? Crit Care Med 2014; 42:e728–e729 2. Ranucci M, Castelvecchio S, Biondi A, et al; Surgical and Clinical Outcome Research (SCORE) Group: A randomized controlled trial of preoperative intra-aortic balloon pump in coronary patients with poor left ventricular function undergoing coronary artery bypass surgery. Crit Care Med 2013; 41:2476–2483 3. Jones RH, Velazquez EJ, Michler RE, et al; STICH Hypothesis 2 Investigators: Coronary bypass surgery with or without surgical ventricular reconstruction. N Engl J Med 2009; 360:1705–1717 4. Ranucci M, Castelvecchio S, Menicanti L, et al: Risk of assessing mortality risk in elective cardiac operations: Age, creatinine, ejection fraction, and the law of parsimony. Circulation 2009; 119:3053–3061 DOI: 10.1097/CCM.0000000000000623
November 2014 • Volume 42 • Number 11
Nevertheless, the study exhibits several weaknesses, which in our eyes do not support the final statement and are not compatible with our findings in the daily life and with those that have partly been published (3): 1) Inclusion criteria for the study were patients undergoing myocardial revascularization with or without associated procedures with a preoperative ejection fraction of less than 35%. Sixty percent of patients in each group underwent combined procedures that were not further specified. Whether this was valve surgery, surgery of the aorta, or even left ventricular (LV) reduction surgery was not reported. Therefore, the risk of comparing two inhomogeneous groups is likely to occur. Especially, operations targeting reshaping of the LV of ischemic patients have been associated with very poor surgical outcome and have been abandoned in most cardiac surgical units. 2) The logistic Euroscore in general overestimates surgical risk, and therefore, it has been revised in its second version, Euroscore II. Nevertheless, operative mortality, especially in the control group, even exceeded this overestimation, which should have been an alarming sign. Although statistically not significant, there is a clear trend toward more mortality in the control group (14% vs 7.3%), which does not support the final statement. 3) IABP insertion was performed in the operating room shortly after induction of anesthesia. As shown by Christenson et al (4), a 2-hour preoperative support is early enough. Trimming this period even further down might not have the same effect. Whether an earlier insertion of the IABP would have had a beneficial effect in this study remains speculative, but in our opinion, this would have been likely to occur. We do, in fact, insert the IABP the evening before the surgical intervention, thereby providing IABP support for at least 10 hours. 4) The indication of surgical revision in the IABP group is 11%, which is exceptionally and unacceptably high and might have contributed to the bad outcomes in this patient group. Patients with postoperative bleeding are prone to (hidden) tamponade and hypovolemia with all negative consequences related to impaired cardiac output. Prevention of this complication is even more crucial in high-risk patients with poor cardiac function. 5) Possible vascular complications after IABP placement are well known, and they are most commonly related to balloon catheter insertion and positioning (e.g., arterial lumen narrowing and limb ischemia). Given the high prevalence of patients with diffuse vascular disease admitted to cardiac surgery departments, it is surprising that peripheral arterial disease or abdominal aortic aneurysm was not reported among the patients with atherosclerosis included in the study. In our institution, we routinely insert the IABP catheter in a sheathless fashion to potentially reduce ischemic vascular complications. From the article, it is not seeable whether this was the case in the study population. Because the IABP is not an active blood pumping device and cardiac performance is improved by indirect means, there are indeed limits to IABP therapy. In conclusion, we have the impression that this patient cohort exceeded those limits and might have even had an indication for an active pump to prevent perioperative low cardiac output syndrome to reach better clinical outcomes. We therefore do not agree to the conclusions of the Critical Care Medicine
article, which in our eyes are misleading. Our considerations aim to keep the debate alive on an increasingly relevant issue in cardiac surgery, given the growing number of patients with poor LV function who will need some sort of support, be it mechanically or pharmacologically to survive the surgical procedure per se. The authors have disclosed that they do not have any potential conflicts of interest. Steffen Pfeiffer, MD, Giuseppe Santarpino, MD, Joachim Sirch, MD, Theodor Fischlein, MD, Ferdinand Vogt, MD, Department of Cardiac Surgery, Cardiovascular Center, Klinikum Nürnberg–Paracelsus Medical University, Nuremberg, Germany
REFERENCES
1. Ranucci M, Castelvecchio S, Biondi A, et al; Surgical and Clinical Outcome Research (SCORE) Group: A Randomized Controlled Trial of Preoperative Intra-Aortic Balloon Pump in Coronary Patients With Poor Left Ventricular Function Undergoing Coronary Artery Bypass Surgery. Crit Care Med 2013; 41:2476–2483 2. Džavík V: Routine intra-aortic balloon pump support in high-risk cardiac surgery patients: Is it time to throw away the pump? Crit Care Med 2013; 41:2642–2644 3. Nabawi F, Santarpino G, Pfeiffer S, et al: Beneficial effect of preoperative intraaortic balloon pumping in patients with low ejection fraction undergoing coronarx artery bypass grafting. Thorac Cardiovasc Surg 2012; 60:PP56 4. Christenson JT, Simonet F, Badel P, et al: Optimal timing of preoperative intraaortic balloon pump support in high-risk coronary patients. Ann Thorac Surg 1999; 68:934–939 DOI: 10.1097/CCM.0000000000000557
The authors reply:
W
e thank Pfeiffer et al (1) for their letter commenting on our study (2) on intra-aortic balloon pump (IABP) in elective high-risk patients undergoing coronary surgery. They raised important issues that we are happy to discuss. 1) There were exactly 33 combined procedures in each group, including mitral valve surgery (14 control group, 19 IABP group), aortic valve replacement (control 3, IABP 4), and surgical ventricular reshaping (control 24, IABP 21). There is no significant difference between groups with respect to surgery, and we can therefore exclude inhomogeneity. Additionally, we would like to point out that many patients received surgical ventricular reshaping, but that the concept expressed by the authors (a procedure with “very poor surgical outcome”) is not supported by the existing evidence. The only randomized controlled trial of surgical ventricular reshaping versus coronary surgery alone (3) ended up with no differences in outcome. 2) It is true that the logistic European system for cardiac operative risk evaluation (EuroSCORE) overestimates the mortality risk. However, in this patient population, it is actually the opposite. The logistic EuroSCORE does not consider very low values of left ventricular ejection fraction and is therefore inappropriate in our patient population, where we had 26.4% of the patients with an ejection fraction less than or equal to 0.25 and 8.2% of the patients with an ejection fraction www.ccmjournal.org
e729
Online Letters to the Editor
less than or equal to 0.20. The age, creatinine, and ejection fraction score (4), which includes the ejection fraction as a continuous variable, provided a mortality risk of about 10%, perfectly in line with the overall mortality of our study. 3) Of course, we cannot exclude that an earlier implantation of the IABP may induce different effects. We understand that this is the usual practice in the authors’ hospital, but we are not aware of any recent study demonstrating that this strategy is effective in hemodynamically stable patients. 4) The authors erroneously ascribe all the surgical revisions to bleeding problems. Actually, we had only five surgical revisions (4.5%) due to bleeding. The other three cases were one laparotomy for suspect mesenteric infarction, one repair of IABP-induced vascular lesion, and one removal of extracorporeal oxygenation circuit. 5) IABP was inserted in a sheathless fashion in our study too. Major vascular complications were detected in one case only. In conclusion, we remain convinced of the possible benefits of IABP therapy in hemodynamically unstable cardiac surgery patients, but we have definitely abandoned the preoperative placement in stable coronary patients with low ejection fraction. Dr. Ranucci consulted for the Sorin Group and lectured for Medtronic, CSL Behring, Grifols SA, and Roche. The remaining authors have disclosed that they do not have any potential conflicts of interest.
e730
www.ccmjournal.org
Marco Ranucci, MD, FESC, Serenella Castelvecchio, MD, FESC, Department of Cardiothoracic–Vascular Anesthesia and Intensive Care, IRCCS Policlinico San Donato, Milan, Italy; Andrea Biondi, MD, Carlo De Vincentiis, MD, Department of Cardiac Surgery, IRCCS Policlinico San Donato, Milan, Italy; Andrea Ballotta, MD, FESC, Department of Cardiothoracic–Vascular Anesthesia and Intensive Care, IRCCS Policlinico San Donato, Milan, Italy; Alessandro Varrica, MD, Alessandro Frigiola, MD, Lorenzo Menicanti, MD, Department of Cardiac Surgery, IRCCS Policlinico San Donato, Milan, Italy
REFERENCES
1. Pfeiffer S, Santarpino G, Sirch J, et al: Does Prophylactic Intra-Aortic Balloon Pumping Really Fail to Improve Perioperative Outcomes in Patients With Poor Left Ventricular Function? Crit Care Med 2014; 42:e728–e729 2. Ranucci M, Castelvecchio S, Biondi A, et al; Surgical and Clinical Outcome Research (SCORE) Group: A randomized controlled trial of preoperative intra-aortic balloon pump in coronary patients with poor left ventricular function undergoing coronary artery bypass surgery. Crit Care Med 2013; 41:2476–2483 3. Jones RH, Velazquez EJ, Michler RE, et al; STICH Hypothesis 2 Investigators: Coronary bypass surgery with or without surgical ventricular reconstruction. N Engl J Med 2009; 360:1705–1717 4. Ranucci M, Castelvecchio S, Menicanti L, et al: Risk of assessing mortality risk in elective cardiac operations: Age, creatinine, ejection fraction, and the law of parsimony. Circulation 2009; 119:3053–3061 DOI: 10.1097/CCM.0000000000000623
November 2014 • Volume 42 • Number 11
