Use of Pulmonary Artery Catheters in Patients with Acute Myocardial Infarction: Discussion (3)
In patients with severe CHF (pulmonary edema) while the mortality was 1.31 times higher in patients receiving PAC, this difference did not reach statistical significance. Moreover, the possibility that even in patients with pulmonary edema, those receiving PAC were “sicker,” or less responsive to treatment, cannot be excluded. We had no data on ejection fraction, pH, urine flow and other important variables that would have to be compared to assure comparability of the groups.
An important finding in our study was that in the small group of patients who were not in “pump failure,” but received PAC, there was an increased mortality. This might arouse further suspicion that the use of PAC independently contributes to mortality. However, a review of the indications for PAC and causes of death in this group revealed that in five patients the catheter was introduced in patients with suspected rupture of the interventricular septum and that this was the cause of death in these five patients. Two further patients died of electromechanical dissociation following progressive blood pressure drop. One patient had brain death following resuscitation. Thus, all the eight deaths in this group are explicable on the basis of the patients’ clinical conditions, and there is no reason to believe that introduction of PAC in any way contributed to their mortality.
In conclusion, on the basis of our findings in a large series of patients, we believe that the introduction of PAC in patients with AMI does not per se increase inhospital mortality. We believe, therefore, that PAC should continue to be used in patients with AMI to guide therapy in those cases in which noninvasive methods do not enable the clinican to assess sufficiently accurately the hemodynamic status and the appropriate treatment to be applied.