Letter by Gomes and Evora Regarding Article, “Early On-Cardiopulmonary Bypass Hypotension and Other Factors Associated With Vasoplegic Syndrome”
To the Editor:
The article by Levin et al1 represents a major contribution to the understanding of basic mechanisms involved in the emergence of vasoplegic syndrome (VS), a recently recognized and dreadful condition that affects patients in the postoperative period of cardiovascular surgery.
However, the Introduction’s assertion that this entity occurs after separation from cardiopulmonary bypass is no longer realistic. The incidence of VS has evolved from the boundaries of earlier descriptions, and these days, widespread occurrence has been reported. Although a lack of consistency in its definition and the absence of specific biomarkers make it difficult to fully characterize this syndrome, the clinical and hemodynamic events observed have been associated with excessive production of nitric oxide.2
VS was initially described as a condition intrinsically linked to cardiopulmonary bypass use in cardiovascular surgery. However, further studies identified the occurrence of VS in patients who underwent off-pump coronary artery bypass surgery, revealing the multifactorial connections associated with the emergence of this syndrome.3
Sun et al,4 in a fresh study reviewing their case series on off-pump coronary artery bypass, demonstrated a remarkable change in which VS turned out to be the most common isolated postoperative complication after off-pump coronary artery bypass (except atrial fibrillation), ahead of rates of stroke, myocardial infarction, renal failure, and major infections. More recently, an additional report5 describes VS that complicates the postoperative course of liver transplantation.
Methylene blue has been recommended as a therapeutic option for catecholamine-resistant VS, with promising results demonstrating attenuation of severity and improved outcomes5; however, the role and effectiveness of methylene blue in this particular condition remain undetermined. Therefore, the information provided by Levin and colleagues1 is central and welcome, likely making it feasible to predict the occurrence of VS on the basis of an intraoperative decline in mean arterial pressure. Certainly, additional prospective studies should be conducted to confirm such findings.
Levin MA, Lin HM, Castillo JG, Adams DH, Reich DL, Fischer GW. Early on-cardiopulmonary bypass hypotension and other factors associated with vasoplegic syndrome. Circulation. 2009; 120: 1664–1671.
Gomes WJ, Erlichman MR, Batista-Filho ML, Knobel M, Almeida DR, Carvalho AC, Catani R, Buffolo E. Vasoplegic syndrome after off-pump coronary artery bypass surgery. Eur J Cardiothorac Surg. 2003; 23: 165–169.
Sun X, Zhang L, Hill PC, Lowery R, Lee AT, Molyneaux RE, Corso PJ, Boyce SW. Is incidence of postoperative vasoplegic syndrome different between off-pump and on-pump coronary artery bypass grafting surgery? Eur J Cardiothorac Surg. 2008; 34: 820–825.