Author: Ajay Kumar Jha, M.D., D.M.
Anesthesiology 1 2018, Vol.128, 227.
To the Editor:
I read the article by Hajjar et al. with great enthusiasm.1 First, I would like to congratulate the authors for their ambitious study and reasonable conclusions. They concluded that vasopressin improved clinical outcomes better than norepinephrine in vasoplegic shock after cardiac surgery. I would like to discuss the concerns associated with the use of a pure vasoconstrictor after cardiac surgery.
Transient or sustained vasoplegia is not uncommon after cardiac surgery and it is characterized by a fall in systemic vascular resistance (SVR).2 In addition, myocardial stunning or hibernation after cardiac surgery commonly results in reduction of left ventricular ejection fraction.3 Furthermore, preoperative low ejection fraction is one of the most documented predictors for vasoplegia after on-pump cardiac surgery.2 A reduction in SVR may be associated with improvement in cardiac index.4 To maintain systemic blood pressure solely by increasing SVR without augmenting cardiac contractility may prove counterproductive.5 Therefore, our target should be to maintain SVR within normal limits.6 Although the authors mentioned that the cardiac index did not change after vasopressor infusion, in patients with reduced ejection fraction, cardiac index expectedly reduces after pure vasoconstrictor infusion.7 Vasopressin-related myocardial dysfunction does not arise as a result of increase in SVR, but from a direct effect on cardiac contractility.8 In the current study, the majority of patients (53%) had a normal preoperative ejection fraction (greater than 60%). Unlike vasopressin, its receptor antagonist has shown to improve left ventricular systolic function.9,10 An assessment of ejection fraction in vasoplegic syndrome would have been ideal for better interpretation of the results of this study. In patients with preserved ejection fraction, vasopressin may prove superior to norepinephrine, but generalization of this study finding in patients with vasoplegic syndrome and diminished ejection fraction could be debatable.
References
Hajjar, LA, Vincent, JL, Barbosa Gomes Galas, FR, Rhodes, A, Landoni, G, Osawa, EA, Melo, RR, Sundin, MR, Grande, SM, Gaiotto, FA, Pomerantzeff, PM, Dallan, LO, Franco, RA, Nakamura, RE, Lisboa, LA, de Almeida, JP, Gerent, AM, Souza, DH, Gaiane, MA, Fukushima, JT, Park, CL, Zambolim, C, Rocha Ferreira, GS, Strabelli, TM, Fernandes, FL, Camara, L, Zeferino, S, Santos, VG, Piccioni, MA, Jatene, FB, Costa Auler, JOJr, Filho, RK Vasopressin versus norepinephrine in patients with vasoplegic shock after cardiac surgery: The VANCS randomized controlled trial. Anesthesiology 2017; 126:85–93
Argenziano, M, Chen, JM, Choudhri, AF, Cullinane, S, Garfein, E, Weinberg, AD, Smith, CRJr, Rose, EA, Landry, DW, Oz, MC Management of vasodilatory shock after cardiac surgery: Identification of predisposing factors and use of a novel pressor agent. J Thorac Cardiovasc Surg 1998; 116:973–80
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Bixler, TJ, Gardner, TJ, Donahoo, JS, Brawley, RK, Potter, A, Gott, VL Improved myocardial performance in postoperative cardiac surgical patients with sodium nitroprusside. Ann Thorac Surg 1978; 25:444–8
Ertmer, C, Morelli, A, Bone, HG, Stubbe, HD, Schepers, R, Van Aken, H, Lange, M, Bröking, K, Lücke, M, Traber, DL, Westphal, M Dobutamine reverses the vasopressin-associated impairment in cardiac index and systemic oxygen supply in ovine endotoxemia. Crit Care 2006; 10:R144
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Dünser, MW, Hasibeder, WR Vasopressin in vasodilatory shock: Ensure organ blood flow, but take care of the heart! Crit Care 2006; 10:172
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Suzuki, S, Yoshihisa, A, Yamaki, T, Sugimoto, K, Kunii, H, Nakazato, K, Abe, Y, Saito, T, Ohwada, T, Suzuki, H, Saitoh, S, Kubota, I, Takeishi, Y AVCMA investigators: Vasopressin V2 receptor antagonist tolvaptan is effective in heart failure patients with reduced left ventricular systolic function and low blood pressure. Int Heart J 2015; 56:213–8
Yamazaki, T, Izumi, Y, Nakamura, Y, Yamashita, N, Fujiki, H, Osada-Oka, M, Shiota, M, Hanatani, A, Shimada, K, Iwao, H, Yoshiyama, M Tolvaptan improves left ventricular dysfunction after myocardial infarction in rats. Circ Heart Fail 2012; 5:794–802
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