The results of this large, international, prospective observational study found that PAC use was associated with a higher risk of the composite mortality and morbidity outcome than non-PAC use in patients undergoing CABG surgery. Significant decline in organ function, increased inotrope and fluid administration, and longer ICU stay were noted in the PAC group.
Smaller observational trials have implicated that PAC monitoring is associated with increased morbidity and decreased survival.9,21 In contrast, several large randomized trials in noncardiac surgery populations have more recently reported no differences in mortality14–19 despite higher rates of catheter-related adverse events14–17 and hemodynamic interventions.14,15 No randomized trials, thus far, have evaluated the efficacy or safety of PAC use in cardiac surgery. Moreover, there are few prospective observational trials in this population, and the only study examining >1000 patients was published >20 years ago.33 Although Schwann et al.34 described that highly selective use of PAC decreased resource utilization and catheter-related risks, inferences that PAC should continue to be used in high-risk patients might not be justified. Despite the paucity of studies specifically targeting the cardiac surgical population, the notion that for these patients, the PAC is useful for guiding rational decisions concerning the administration of fluids, inotropes, and diuretics18,19 has remained unchallenged over the past 2 decades.
Cardiac surgical patients experience unique physiological challenges, many of which are at least partly due to CPB.35 Biventricular dysfunction, ventricular underfilling, and extremes of vascular tone (vasoconstriction or vasoplegia36) are common causes of inadequate microcirculatory flow during and after CPB. A PAC provides more precise physiologic data than CVP (or no central pressure monitoring) for early detection of perfusion abnormalities, potentially forestalling tissue hypoxia.37,38
Hence, unexpected was our finding that patients managed with a PAC experienced higher rates of in-hospital death and organ failure than did similar propensity-matched patients managed with CVP monitoring alone. One possible explanation for this may be that intensive hemodynamic manipulations and interventions as a result of the presence of a PAC and its associated data may be responsible for the deleterious effect of this mode of monitoring on perioperative outcome.
Another explanation for the lack of effectiveness of a PAC in improving outcome in different patient populations6,9,14–16 might be related to the limitations of pulmonary capillary wedge pressure to reflect left ventricular end-diastolic volume. Alternatively, others postulate that PAC-directed therapy, including the use of fluids and inotropes, may be ineffective or harmful.10,11
Data from observational, matched-pair cohort studies have been reported to show improved exercise tolerance in heart failure15 and improved outcome in refractory circulatory shock.20 Yet, in the second-largest randomized trial evaluating the PAC catheter (n = 1041), Harvey et al.16 reported no differences in survival, in-hospital mortality, or ICU length of stay in adult medical and surgical patients admitted with APACHE scores >25. The investigators concluded that the true benefit of the PAC (if any) would not be evident without clinical trials testing specific PAC data-driven management protocols.
The ESCAPE trial evaluated the effectiveness of the PAC in a randomized group of 433 nonsurgical CHF patients.15 These findings suggested that PAC-guided vasodilator and diuretic therapy was not superior to clinical assessment alone in reducing death or hospital stay. Therapy to reduce intravascular volume overload during hospitalization for heart failure led to marked improvement in signs and symptoms of increased filling pressures in patients monitored with or without a PAC. For this group of chronic CHF patients, addition of the PAC to clinical assessment increased anticipated adverse events, but did not affect overall mortality and hospitalization.
In our study, the primary analysis included 54 out of 1273 non-PAC patients, who received a PAC after CPB. Almost all (96%) of the cross-overs occurred after ICU admission. Patients with an unplanned PAC insertion were included and analyzed as part of their original non-PAC treatment group and had an in-hospital mortality rate of 18.5%. Most likely, the PAC insertion was a clinical response to a catastrophic and unpreventable perioperative event.
Our study assessed the association between the clinical use of PAC and outcome, using prospectively defined hypotheses and definitions. Because the patient group assignment was not randomized, differences in covariates between PSMP may have influenced the treatment selection (preferential PAC insertion and monitoring of sicker patients) and biased the results. This was addressed by comparing multiple demographic, hospital admission, and immediate preoperative risk factors possibly associated with patient selection into treatment groups before and after propensity matching. Table 1 shows that PSMP pairs had similar incidences of preoperative and early intraoperative risk factors previously validated to be strongly related to outcome (Euro SCORE; 20 markers of previous or present myocardial impairment or vulnerability; evidence of major noncardiac organ system dysfunction; and requirement of either emergency or combined (valve/CABG) operation).39,40 Furthermore, we accounted for the variability of PAC insertion frequencies (1%–99%) by specific center sites. However, there is still the possibility that covariates that influence treatment selection and outcome remain unevaluated. Our study supplies a real-world view of the use of PACs in the surgical coronary revascularization setting. Although results from prospective, randomized clinical trials are considered the highest level of evidence for evaluating monitoring modalities and medical therapies, well-conducted observational trials can provide similar results.41–43 It has been suggested that prospectively randomized trials test efficacy under ideal conditions and that observational studies test effectiveness in everyday practice.44
Another limitation of our study is the age of the collected data. Albeit practice patterns for perioperative care of the cardiac surgical patient (other than use of intraoperative TEE) constantly underlie improvements and slight changes, the observed effects related to monitoring at the time of data collection are not significantly different from those used currently. By eliminating patients who had intraoperative TEE from our study population, we were able to focus the study on the role of PAC on outcome. Finally, although regional differences in treatment protocols may have affected the results, these same differences persist.45
Another limitation of this study is the inability to separate the contribution of PAC monitoring alone from monitoring-induced interventions on outcome. Unlike the Sandham et al. analysis, we chose to assess the impact of PAC monitoring without a hemodynamic protocol, because it better reflects the current practice patterns in cardiac surgery.14,46,47 In the operating room, physiologic variables are measured, interpreted, and treated in real-time by providers.48 Cardiac programs contributing patients to the dataset are high-volume centers with experienced cardiac teams; however, it is still possible that the PAC data were inaccurate or misinterpreted in this setting.
We conclude that the use of PACs confers no benefit among patients undergoing coronary revascularization surgery requiring CPB. Our data also indicate that PAC use triggers more frequent and more intensive hemodynamic interventions, suggesting a mechanism for the increased rate of complications and adverse outcome associated with PAC use. Although a randomized controlled trial would be ideal to confirm our findings, we recognize that imbedded practice and bias limitations would make such a trial difficult to conduct.
Body surface area, m2
American Indian, African American, or Hispanic ethnicity
Congestive heart failure
Percutaneous transluminal coronary angioplasty (PTCA)/ coronary atherectomy/intracoronary stent
Coronary artery bypass graft surgery (CABG)
Other cardiac surgery
Other noncardiac surgery
Peripheral vascular disease
Moderate left-ventricular dysfunction
Severe left-ventricular dysfunction
Intra-aortic balloon pump (IABP)
Medication of inotropes/vasoconstrictors
Serum creatinine >200 μmol/L
Myocardial infarction prior to surgery within 90 days
Congestive heart failure (admission/preoperative)
Combined cardiac surgery
Combined surgery on thoracic aorta
APPENDIX 2 MCSPI EPI II LIST OF CENTERS AND PRINCIPAL INVESTIGATORS
The Ischemia Research and Education Foundation (IREF) is an independent nonprofit foundation, formed in 1987, that develops clinical investigators via observational studies and clinical trials addressing ischemic injury of the heart, brain, kidney, and gastrointestinal tract. IREF provided all funding for execution of the study, collection of the data, and analysis and publication of the findings. The Multicenter Study of Perioperative Ischemia (McSPI) Research group, formed in 1988, is an association of 160 international medical centers located in 23 countries, organized through, and supported by grants from, IREF.
The following institutions and persons coordinated the McSPI EPI II study: Study Chairman—D. Mangano; Senior Editors—J. Levin and L. Saidman; Study Design and Analysis Center: Ischemia Research and Education Foundation—P. Barash, C. Dietzel, A. Herskowitz, Y. Miao, and I. C. Tudor; Editorial/Administrative group—D. Beatty, I. Lei, and B. Xavier.
The following institutions and persons participated in the McSPI EPI II study:
United States: University of Chicago, Weiss Memorial Hospital—S. Aronson; Beth Israel Hospital—M. Comunale; Massachusetts General—M. D'Ambra; University of Rochester—M. Eaton; Baystate Medical Center—R. Engelman; Baylor College of Medicine—J. Fitch; Duke Medical Center—K. Grichnik; UTHSCSA—Audie Murphy VA and UTHSCSA—University Hospital—C. B. Hantler; St. Luke's Roosevelt Hospital—Z. Hillel; New York University Medical Center—M. Kanchuger and J. Ostrowski; Stanford University Medical Center—C. M. Mangano; Yale University School of Medicine—J. Mathew, M. Fontes, P. Barash; University of Wisconsin—M. McSweeney, R. Wolman; University of Arkansas for Medical Sciences—C. A. Napolitano; Discovery Alliance, Inc.—L. A. Nesbitt; VA Medical Center, Milwaukee—N. Nijhawan; Texas Heart Institute, Mercy Medical Center—N. Nussmeier; University of Texas Medical School, Houston—E. G. Pivalizza; University of Arizona—S. Polson; Emory University Hospital—J. Ramsay; Kaiser Foundation Hospital—G. Roach; Thomas Jefferson University Hospital and MCP Hahnemann University Hospital—N. Schwann; VAMC Houston—S. Shenaq; Maimonides Medical Center—K. Shevde; Mt. Sinai Medical Center—L. Shore-Lesserson and D. Bronheim; University of Michigan—J. Wahr; University of Washington—B. Spiess; VA Medical Center, S. F.—A. Wallace; Austria—University of Graz—H. Metzler.
Canada: University of British Columbia—D. Ansley and J. P. O'Connor; The Toronto Hospital—D. Cheng; Laval Hospital, Quebec—D. Côte; Health Sciences Centre, University of Manitoba—P. Duke; University of Ottawa Heart Institute—J. Y. Dupuis and M. Hynes; University of Alberta Hospital—B. Finegan; Montreal Heart Institute—R. Martineau and P. Couture; St. Michael's Hospital, University of Toronto—D. Mazer.
Colombia: Fundacion Clinico Shaio—J. C. Villalba and M. E. Colmenares.
France: CHRU Le Bocage—C. Girard; Hospital Pasteur—C. Isetta; Germany—Universität Wûrzburg—C. A. Greim and N. Roewer; Universität Bonn—A. Hoeft; University of Halle—R. Loeb and J. Radke; Westfalische Wilhelms—Universität Munster—T. Mollhoff; Universität Heidelberg—J. Motsch and E. Martin; Ludwig-Maximillians Universität—E. Ott; Universität Krankenhaus Eppendorf—J. Scholz and P. Tonner; Georg-August Universität Göttingen—H. Sonntag; Ludwig-Maximillians Universität (Department of Cardiac Surgery)—P. Ueberfuhr.
Hungary: Orszagos Kardiologiai Intezet—A. Szekely.
India: Escorts Heart Institute—R. Juneja; Apollo Hospital—G. Mani.
Israel: Hadassah University Hospital—B. Drenger, Y. Gozal, and E. Elami.
Italy: San Raffaele Hospital, Universita de Milano—C. Tommasino.
Mexico: InstitutoNacional de Cardiologia—P. Luna.
The Netherlands: University Hospital Maastricht—P. Roekaerts and S. DeLange.
Poland: Institute of Cardiology—R. Pfitzner.
Romania: Institute of Cardiology—D. Filipescu.
Thailand: Siriraj Hospital—U. Prakanrattana.
United Kingdom: Glenfield Hospital—D. J. R. Duthie; St. Thomas' Hospital—R. O. Feneck; The Cardiothoracic Centre, Liverpool—M. A. Fox; South Cleveland Hospital—J. D. Park; Southampton General Hospital—D. Smith; Manchester Royal Infirmary—A. Vohra; Papworth Hospital—A. Vuylsteke and R. D. Latimer.
1. Swan HJ, Ganz W, Forrester J, Marcus H, Diamond G, Chonette D. Catheterization of the heart in man with use of a flow-directed balloon-tipped catheter. N Engl J Med 1970;283:447–51
2. American Society of Anesthesiologists Task Force on Pulmonary Artery Catheterization. Practice guidelines for pulmonary artery catheterization: an updated report by the American Society of Anesthesiologists Task Force on Pulmonary Artery Catheterization. Anesthesiology 2003;99:775–6
3. Wiener RS, Welch HG. Trends in the use of the pulmonary artery catheter in the United States, 1993–2004. JAMA 2007;298:423–9
4. Jacka MJ, Cohen MM, To T, Devitt JH, Byrick R. The use of and preferences for the transesophageal echocardiogram and pulmonary artery catheter among cardiovascular anesthesiologists. Anesth Analg 2002;94:1065–71
5. Jacka MJ, Cohen MM, To T, Devitt JH, Byrick R. The appropriateness of the pulmonary artery catheter in cardiovascular surgery. Can J Anaesth 2002;49:276–82
6. Ramsey SD, Saint S, Sullivan SD, Dey L, Kelley K, Bowdle A. Clinical and economic effects of pulmonary artery catheterization in nonemergent coronary artery bypass graft surgery. J Cardiothorac Vasc Anesth 2000;14:113–8
7. Ferguson TB Jr, Hammill BG, Peterson ED, DeLong ER, Grover FL. A decade of change—risk profiles and outcomes for isolated coronary artery bypass grafting procedures, 1990–1999: a report from the STS National Database Committee and the Duke Clinical Research Institute. Society of Thoracic Surgeons. Ann Thorac Surg 2002;73:480–9
8. Horan PG, Leonard N, Herity NA. Progressively increasing operative risk among patients referred for coronary artery bypass surgery. Ulster Med J 2006;75:136–40
9. Connors AF Jr, Speroff T, Dawson NV, Thomas C, Harrell FE Jr, Wagner D, Desbiens N, Goldman L, Wu AW, Califf RM, Fulkerson WJ Jr, Vidaillet H, Broste S, Bellamy P, Lynn J, Knaus WA. The effectiveness of right heart catheterization in the initial care of critically ill patients. SUPPORT Investigators. JAMA 1996;276:889–97
10. Rapoport J, Teres D, Steingrub J, Higgins T, McGee W, Lemeshow S. Patient characteristics and ICU organizational factors that influence frequency of pulmonary artery catheterization. JAMA 2000;283:2559–67
11. Yu DT, Black E, Sands KE, Schwartz JS, Hibberd PL, Graman PS, Lanken PN, Kahn KL, Snydman DR, Parsonnet J, Moore R, Platt R, Bates DW. Severe sepsis: variation in resource and therapeutic modality use among academic centers. Crit Care 2003;7:R24–34
12. Vincent JL. A reappraisal for the use of pulmonary artery catheters. Crit Care 2006;10(Suppl 3):S1
13. Vincent JL, Dhainaut JF, Perret C, Suter P. Is the pulmonary artery catheter misused? A European view. Crit Care Med 1998;26:1283–7
14. Sandham JD, Hull RD, Brant RF, Knox L, Pineo GF, Doig CJ, Laporta DP, Viner S, Passerini L, Devitt H, Kirby A, Jacka M. A randomized, controlled trial of the use of pulmonary-artery catheters in high-risk surgical patients. N Engl J Med 2003;348:5–14
15. Binanay C, Califf RM, Hasselblad V, O'Connor CM, Shah MR, Sopko G, Stevenson LW, Francis GS, Leier CV, Miller LW. Evaluation study of congestive heart failure and pulmonary artery catheterization effectiveness: the ESCAPE trial. JAMA 2005;294:1625–33
16. Harvey S, Harrison DA, Singer M, Ashcroft J, Jones CM, Elbourne D, Brampton W, Williams D, Young D, Rowan K. Assessment of the clinical effectiveness of pulmonary artery catheters in management of patients in intensive care (PAC-Man): a randomised controlled trial. Lancet 2005;366: 472–7
17. Wheeler AP, Bernard GR, Thompson BT, Schoenfeld D, Wiedemann HP, deBoisblanc B, Connors AF Jr, Hite RD, Harabin AL. Pulmonary-artery versus central venous catheter to guide treatment of acute lung injury. N Engl J Med 2006;354:2213–24
18. Rhodes A, Cusack RJ, Newman PJ, Grounds RM, Bennett ED. A randomised, controlled trial of the pulmonary artery catheter in critically ill patients. Intensive Care Med 2002;28:256–64
19. Richard C, Warszawski J, Anguel N, Deye N, Combes A, Barnoud D, Boulain T, Lefort Y, Fartoukh M, Baud F, Boyer A, Brochard L, Teboul JL, French Pulmonary Artery Catheter Study group. Early use of the pulmonary artery catheter and outcomes in patients with shock and acute respiratory distress syndrome: a randomized controlled trial. JAMA 2003;290: 2713–20
20. Cohen MG, Kelly RV, Kong DF, Menon V, Shah M, Ferreira J, Pieper KS, Criger D, Poggio R, Ohman EM, Gore J, Califf RM, Granger CB. Pulmonary artery catheterization in acute coronary syndromes: insights from the GUSTO IIb and GUSTO III trials. Am J Med 2005;118:482–8
21. Peters SG, Afessa B, Decker PA, Schroeder DR, Offord KP, Scott JP. Increased risk associated with pulmonary artery catheterization in the medical intensive care unit. J Crit Care 2003;18:166–71
22. Mimoz O, Rauss A, Rekik N, Brun-Buisson C, Lemaire F, Brochard L. Pulmonary artery catheterization in critically ill patients: a prospective analysis of outcome changes associated with catheter-prompted changes in therapy. Crit Care Med 1994;22:573–9
23. Schwann NM, Mangano DT. Pulmonary-artery catheters in high-risk surgical patients. N Engl J Med 2003;348:2035–7
24. Mangano DT. Aspirin and mortality from coronary bypass surgery. N Engl J Med 2002;347:1309–17
25. Mangano DT, Browner WS, Hollenberg M, London MJ, Tubau JF, Tateo IM. Association of perioperative myocardial ischemia with cardiac morbidity and mortality in men undergoing noncardiac surgery. The Study of Perioperative Ischemia Research group. N Engl J Med 1990;323:1781–8
26. Roach GW, Kanchuger M, Mangano CM, Newman M, Nussmeier N, Wolman R, Aggarwal A, Marschall K, Graham SH, Ley C. Adverse cerebral outcomes after coronary bypass surgery. Multicenter Study of Perioperative Ischemia Research group and the Ischemia Research and Education Foundation Investigators. N Engl J Med 1996;335:1857–63
27. Goldstein LB, Bertels C, Davis JN. Interrater reliability of the NIH stroke scale. Arch Neurol 1989;46:660–2
28. Mangano CM, Diamondstone LS, Ramsay JG, Aggarwal A, Herskowitz A, Mangano DT. Renal dysfunction after myocardial revascularization: risk factors, adverse outcomes, and hospital resource utilization. The Multicenter Study of Perioperative Ischemia Research group. Ann Intern Med 1998;128:194–203
29. D'Agostino RB Jr. Propensity score methods for bias reduction in the comparison of a treatment to a non-randomized control group. Stat Med 1998;17:2265–81
30. Gum PA, Thamilarasan M, Watanabe J, Blackstone EH, Lauer MS. Aspirin use and all-cause mortality among patients being evaluated for known or suspected coronary artery disease: a propensity analysis. JAMA 2001;286:1187–94
31. Grzybowski M, Clements EA, Parsons L, Welch R, Tintinalli AT, Ross MA, Zalenski RJ. Mortality benefit of immediate revascularization of acute ST-segment elevation myocardial infarction in patients with contraindications to thrombolytic therapy: a propensity analysis. JAMA 2003;290:1891–8
32. Vikram HR, Buenconsejo J, Hasbun R, Quagliarello VJ. Impact of valve surgery on 6-month mortality in adults with complicated, left-sided native valve endocarditis: a propensity analysis. JAMA 2003;290:3207–14
33. Tuman KJ, McCarthy RJ, Spiess BD, DaValle M, Hompland SJ, Dabir R, Ivankovich AD. Effect of pulmonary artery catheterization on outcome in patients undergoing coronary artery surgery. Anesthesiology 1989;70:199–206
34. Schwann TA, Zacharias A, Riordan CJ, Durham SJ, Engloren M, Habib RH. Safe, highly selective use of pulmonary artery catheters in coronary artery bypass grafting: an objective patient selection method. Ann Thorac Surg 2002;73:1394–401
35. Murkin J, Pathophysiology of cardiopulmonary bypass. Can J Anaesth 1989;36:41–4
36. 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;120:1664–71
37. Rackow EC, Astiz ME, Weil MH. Cellular oxygen metabolism during sepsis and shock. The relationship of oxygen consumption to oxygen delivery. JAMA 1988;259:1989–93
38. Verrier ED, Boyle EM Jr. Endothelial cell injury in cardiovascular surgery. Ann Thorac Surg 1996;62:915–22
39. Nashef SA, Roques F, Hammill BG, Peterson ED, Michel P, Grover FL, Wyse RK, Ferguson TB. Validation of European System for Cardiac Operative Risk Evaluation (EuroSCORE) in North Am cardiac surgery. Eur J Cardiothorac Surg 2002; 22:101–5
40. Nashef SA, Roques F, Michel P, Gauducheau E, Lemeshow S, Salamon R. European system for cardiac operative risk evaluation (EuroSCORE). Eur J Cardiothorac Surg 1999;16:9–13
41. Concato J, Shah N, Horwitz RI. Randomized, controlled trials, observational studies, and the hierarchy of research designs. N Engl J Med 2000;342:1887–92
42. Benson K, Hartz AJ. A comparison of observational studies and randomized, controlled studies. N Engl J Med 2000; 342:1878–86
43. Kahlert K, Erbel R. Transcatheter aortic valve implantation in the era after commericialization:quo vadis in the real world? Circulation 2011;123:239–41
44. Antman EM. Evidence and education. Circulation 2011; 123:681–5
45. Maddux FW, Dickinson TA, Rilla D, Kamienski RW, Saha SP, Eales F, Rego A, Donias HW, Crutchfield SL, Hardin RA. Institutional variability of intraoperative red blood cell utilization in coronary artery bypass graft surgery. Am J Med Qual 2009;24:403–11
46. Buhre W, Rossaint R. Perioperative management and monitoring in anaesthesia. Lancet 2003;362:1839–46
47. Pulmonary Artery Catheter Consensus conference: consensus statement. Crit Care Med 1997;25:910–25
48. Staples JR, Ramsay JG. Advances in anesthesia for cardiac surgery: an overview for the 1990s. AACN Clin Issues 1997;8:41–9