Major factors in the controversy of pulsatile versus nonpulsatile flow during acute and chronic cardiac support.

During the past 50 years, the controversy over the benefits of pulsatile versus nonpulsatile flow in cardiac surgery has not been solved.1 A detailed investigation in all published literature reveals that in a majority of publications, the investigators could not show any differences between perfusion modes during acute or chronic cardiac support. However, in more than 20 articles, it appears clear that pulsatile flow causes significantly less vital organ injury and systemic inflammation during cardiopulmonary bypass (CPB) procedures and chronic cardiac circulatory support.1–23 To the best of our knowledge, there is not a single publication that clearly shows the benefits of nonpulsatile perfusion over pulsatile perfusion in acute or chronic clinical or animal settings. The pro-nonpulsatile flow investigators can only claim that there is no difference between perfusion modes, whereas the pro-pulsatile investigators have documented clear benefits.1–23 The objective of this editorial is to examine the major causes for this continuing controversy and suggest potential solutions to end it. Following are the two major causes for the controversy, and both are valid for acute or chronic settings.

[1]  A Undar,et al.  Pulsatile and nonpulsatile flows can be quantified in terms of energy equivalent pressure during cardiopulmonary bypass for direct comparisons. , 1999, ASAIO journal.

[2]  K. Sun,et al.  The Effects of Pulsatile Flow Upon Renal Tissue Perfusion During Cardiopulmonary Bypass: A Comparative Study of Pulsatile and Nonpulsatile Flow , 2005, ASAIO journal.

[3]  H. Harasaki,et al.  Comparison of pulsatile and non‐pulsatile cardiopulmonary bypass on regional renal blood flow in sheep , 2004, Scandinavian cardiovascular journal : SCJ.

[4]  A. Undar Energy equivalent pressure formula is for precise quantification of different perfusion modes. , 2003, Annals of Thoracic Surgery.

[5]  C. Fraser,et al.  Impact of membrane oxygenators on pulsatile versus nonpulsatile perfusion in a neonatal model , 2000, Perfusion.

[6]  R Fumero,et al.  Clinical experience with a new pulsatile pump for infant and pediatric cardiopulmonary bypass. , 1989, The International journal of artificial organs.

[7]  Akif Ündar,et al.  Myths and truths of pulsatile and nonpulsatile perfusion during acute and chronic cardiac support. , 2004 .

[8]  A. Undar,et al.  The relation between pump flow rate and pulsatility on cerebral hemodynamics during pediatric cardiopulmonary bypass [1] (multiple letters) , 1998 .

[9]  C. Fraser,et al.  Pulsatile Perfusion Improves Regional Myocardial Blood Flow during and after Hypothermic Cardiopulmonary Bypass in a Neonatal Piglet Model , 2000, ASAIO journal.

[10]  A. Undar,et al.  How should investigators compare different perfusion modes or different types of pulsatile flow during chronic support? , 2004, ASAIO journal.

[11]  S. Honda,et al.  Open-heart surgery in infants using pulsatile high-flow cardiopulmonary bypass. , 1989, The Journal of cardiovascular surgery.

[12]  A. Ündar,et al.  AN IN VIVO COMPARISON OF INFANT MEMBRANE OXYGENATORS FOR PULSATILE CARDIOPULMONARY BYPASS , 1996 .

[13]  M. Onoe,et al.  A clinical study on the effects of pulsatile cardiopulmonary bypass on the blood endotoxin levels. , 1994, The Journal of thoracic and cardiovascular surgery.

[14]  A Undar,et al.  Effects of perfusion mode on regional and global organ blood flow in a neonatal piglet model. , 1999, The Annals of thoracic surgery.

[15]  R B Shepard,et al.  Energy equivalent pressure. , 1966, Archives of surgery.

[16]  A. Buchan,et al.  A randomized study of the influence of perfusion technique and pH management strategy in 316 patients undergoing coronary artery bypass surgery. I. Mortality and cardiovascular morbidity. , 1995, The Journal of thoracic and cardiovascular surgery.

[17]  A. Ündar Universal and precise quantification of pulsatile and nonpulsatile pressure flow waveforms is necessary for direct and adequate comparisons among the results of different investigators. , 2003 .

[18]  A D Edwards,et al.  The relation between pump flow rate and pulsatility on cerebral hemodynamics during pediatric cardiopulmonary bypass. , 1997, The Journal of thoracic and cardiovascular surgery.

[19]  H. Scheld,et al.  Left ventricular pressure and volume unloading during pulsatile versus nonpulsatile left ventricular assist device support. , 2004, The Annals of thoracic surgery.

[20]  A. Undar The ABCs of research on pulsatile versus nonpulsatile perfusion during cardiopulmonary bypass. , 2002, Medical Science Monitor.

[21]  A Undar,et al.  The type of aortic cannula and membrane oxygenator affect the pulsatile waveform morphology produced by a neonate-infant cardiopulmonary bypass system in vivo. , 1998, Artificial organs.

[22]  Y Sezai,et al.  The role of pulsatility in end-organ microcirculation after cardiogenic shock. , 1996, ASAIO journal.

[23]  E. Berjano,et al.  Injury in organs after cardiopulmonary bypass: a comparative experimental morphological study between a centrifugal and a new pulsatile pump. , 2004, Artificial organs.

[24]  Akif Ündar,et al.  Fundamentals of pulsatile versus nonpulsatile flow during chronic support. , 2003 .

[25]  A. Undar,et al.  Comparison of six pediatric cardiopulmonary bypass pumps during pulsatile and nonpulsatile perfusion. , 2001, The Journal of thoracic and cardiovascular surgery.

[26]  G Wright,et al.  Mechanical simulation of cardiac function by means of pulsatile blood pumps. , 1997, Journal of cardiothoracic and vascular anesthesia.

[27]  T. Gourlay,et al.  Pulsatile Flow Compatibility of a Group of Membrane Oxygenators , 1987 .

[28]  E. Berjano,et al.  Platelet Dysfunction in Cardiopulmonary Bypass: An Experimental Comparative Study between a Centrifugal and a New Pulsatile Pump , 2003, The International journal of artificial organs.

[29]  G. Rakhorst,et al.  Augmentation of Abdominal Organ Perfusion during Cardiopulmonary Bypass with a Novel Intra-aortic Pulsatile Catheter Pump , 2005, The International journal of artificial organs.

[30]  A. Undar,et al.  Pediatric physiologic pulsatile pump enhances cerebral and renal blood flow during and after cardiopulmonary bypass. , 2002, Artificial organs.

[31]  I. Saito,et al.  Microcirculation of the Bulbar Conjunctiva in the Goat Implanted with a Total Artificial Heart: Effects of Pulsatile and Nonpulsatile Flow , 2004, ASAIO journal.

[32]  A. Undar,et al.  Stöckert roller pump generated pulsatile flow: cerebral metabolic changes in adult cardiopulmonary bypass. , 1998, Perfusion.

[33]  A. Undar,et al.  The alphabet of research on pulsatile and nonpulsatile (continuous flow) perfusion during chronic support. , 2002, Artificial organs.

[34]  John L. Myers,et al.  Precise Quantification of Pressure Flow Waveforms of a Pulsatile Ventricular Assist Device , 2005, ASAIO journal.

[35]  A Undar,et al.  Defining pulsatile perfusion: quantification in terms of energy equivalent pressure. , 1999, Artificial organs.

[36]  A. Undar,et al.  Impact of pulsatile flow on microcirculation. , 2004, ASAIO journal.

[37]  G. Chow,et al.  Stöckert roller pump generated pulsatile flow: cerebral metabolic changes in adult cardiopulmonary bypass. , 1997, Perfusion.

[38]  K. Nakata,et al.  Cytokine and endothelial damage in pulsatile and nonpulsatile cardiopulmonary bypass. , 1999, Artificial organs.

[39]  A. Undar Fundamentals of pulsatile versus nonpulsatile flow during chronic support. , 2003, ASAIO journal.