Lessons from ESCAPE: the PAC may not kill, but when should we consider ‘tailored’ therapy?
Stanford University, Stanford, CA, USA
Corresponding author. Tel: +1 650 498 6605. E-mail address: shunt{at}cvmed.stanford.edu
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This article summarizes the results of the recent ESCAPE trial of the use of pulmonary artery catheter for haemodynamic monitoring and clinical decision making in patients with acute heart failure and proposes several clinical situations not included in the trial, which may be appropriate situations to use such monitoring.
Key Words: Pulmonary artery catheter • Decompensated heart failure
The pulmonary artery catheter (PAC) was introduced in 1970 to ‘...provide information considered important for diagnosis and monitoring that was not available from other clinical sources.’1 In the years that followed its introduction, such monitoring became very widely used for diagnosis, monitoring, and guiding treatment of a number of different conditions. However, controversy arose and persisted regarding the safety as opposed to the benefit of using this approach. One early observational study suggested higher mortality for patients thought to require PAC monitoring during hospitalization, although without excess risk for patients with heart failure.2 Other reports from acute MI populations also raised concerns that PACs increased mortality, and a moratorium on the use of the devices was strongly proposed.3 In this setting, the National Heart, Lung, and Blood Institute, the Food and Drug Administration, and others in the USA commenced a trial to test the safety and potential benefit of using the PAC in patients with chronic heart failure.4 The trial commenced enrolling patients in January 2000 and closed enrolment in November 2003 at the recommendation of the data safety and monitoring board (DSMB) after enrolling 433 patients at 26 experienced heart failure centres in the USA and Canada.
For patients hospitalized for severe heart failure, the primary hypothesis of the study was that therapy guided by PAC monitoring plus clinical assessment would lead to more days alive and fewer days hospitalized during the following 6 months when compared with therapy guided by clinical assessment alone. The inclusion criteria of the study were designed to select target patients for whom the clinical decision to use or not to use a PAC could be reasonably categorized as being in a state of ‘equipoise’ or true uncertainty. For the authors, ‘The target patient was sufficiently ill with advanced heart failure to make the use of the PAC reasonable, but also sufficiently stable to make crossover to PAC for urgent management unlikely.’5 Patients were treated by their attending heart failure cardiologist with standard drugs including diuretics, vasodilators, and inotropic agents (with concomitant use of ACE-inhibitors and beta-blockers), with the target of therapy being the reduction of clinical congestion.
The trial was terminated prior to the enrolment of the planned 500 patients at the recommendation of the DSMB due to concerns of early adverse events and the unlikelihood of achieving a significant difference in the primary endpoint. In analysis of the randomized 433 patients, the use of a PAC did not affect the primary endpoint of days alive out of hospital, and the overall neutrality of the PAC intervention was consistent across subgroups (age, gender, race, cardiac index, and site enrolled). Both groups had improvements in exercise and quality-of-life assessments, with a non-significant trend for a greater improvement in the PAC group. There were complications related to the PAC in 4.2% of the PAC group and 0.5% of the control group. The overall frequency of adverse events was 22% in the PAC group and 11% in the clinical assessment group.
Thus, the study demonstrated conclusively that although there was no increase in death or hospitalization associated with the use of the PAC, there was also no benefit associated with the use of PAC in patients with decompensated heart failure. However, as the patients studied did not have a definite indication for the PAC guided therapy, these data cannot be extrapolated to patients who do have such an indication. What such indications actually are remains an open question. For the sake of discussion, this author would suggest considering the following as indications for the use of PAC guided therapy.
- Critical cardiac decompensation. There is no randomized information, but there is a consensus that some patients with advanced disease are so fragile or tenuous that they can only be managed intelligently with haemodynamic data feedback.
- When evaluating patients for cardiac transplantation or mechanical circulatory assistance. There is a general consensus that haemodynamic data are important in making decisions regarding these therapeutic options.
- When there is uncertainty regarding haemodynamic status. Examples might include patients with both COPD and HF, patients with frequent ischaemia and chronic HF, or situations where the systemic vascular resistance may be unusually low or high.
- When patients have persistent symptoms despite empiric adjustment of therapy based on clinical judgment. There may be a need to validate or check the results of using clinical judgment.
Thus, in 2006, the issue of routine use of PAC-guided therapy for decompensated heart failure seems to have been put to rest. However, the device remains an extremely important tool in the management of many patients in the categories outlined earlier.
Conflict of interest: none declared.
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- Swan HJ, Ganz W, Forrester J, et al. (1970) Catheterization of the heart in man with use of a flow-directed balloon-tipped catheter. N Engl J Med 283:447–451.[Web of Science][Medline]
- Connors AF, Speroff T, Dawson NV, et al. (1996) The effectiveness of right heart catheterization in the initial care of critically ill patients. SUPPORT investigators. JAMA 276:889–897.
[Abstract/Free Full Text] - Dalen JE and Bone RC. (1996) Is it time to pull the pulmonary artery catheter? JAMA 276:916–918.
[Abstract/Free Full Text] - Shah MR, O'Connor CM, Sopko G, et al. (2001) Evaluation study of congestive heart failure and pulmonary artery catheterization effectiveness (ESCAPE): design and rationale. Am Heart J 141:528–535.[CrossRef][Web of Science][Medline]
- The ESCAPE Investigators and ESCAPE Study Coordinators. (2005) Evaluation study of congestive heart failure and pulmonary artery catheterization effectiveness: the ESCAPE trial. JAMA 294:1625–1633.
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