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Correspondence  |   March 2001
Perioperative Myocardial Infarction (PMI): A Never-ending Story
Author Affiliations & Notes
  • Thomas Mollhoff, M.D., M.Sc., Ph.D.
    *
  • *Klinik und Poliklinik für Anästhes- iologie und operative Intensivmedizin, Westfälische Wilhelms-Universität Münster, Münster, Germany. moellhoff@anit.uni-muenster.de
Article Information
Correspondence
Correspondence   |   March 2001
Perioperative Myocardial Infarction (PMI): A Never-ending Story
Anesthesiology 3 2001, Vol.94, 540-541. doi:
Anesthesiology 3 2001, Vol.94, 540-541. doi:
To the Editor:—
We read with great interest the article on analysis of risk factors for myocardial infarction and cardiac mortality by Sprung et al.  1 Some statements however, need clarification.
The reported overall incidence of perioperative myocardial infarction (PMI) in this high-risk population is extremely low (1.54%). In contrast, Badner et al.  2 found the incidence of PMI to be more than 3.5 times higher (5.6%). Sprung identified PMI by clinical symptoms, creatine kinase–myocardial band increases, or diagnosis of new Q waves on the electrocardiogram. Badner et al.  2 additionally determined troponin concentrations. He also found that PMI was an early event only occasionally associated with chest pain and usually non–Q wave in nature. This clearly shows that the incidence of PMI reported by Sprung et al.  1 was underestimated, and that the results should be interpreted with caution.
General anesthesia was associated with a significantly greater risk of PMI. 1 Does this mean that regional anesthesia in these high-risk patients resulted in significantly lower incidence of PMI? Was there any difference in postoperative pain therapy between groups? For more than a decade, there has been an ongoing discussion of whether general or regional anesthesia is more beneficial in patients at increased cardiac risk. In 1996, an editorial stated that no more studies were needed to answer this question 3 because the largest study at the time showed no difference in outcome. 4 A retrospective analysis comparing the effects of general and regional anesthesia on outcome in patients with hip fracture repair also showed no significant difference in PMI. However, use of general anesthesia decreased from 95% in 1981 to 47% in 1993. 5 The reasons for enhanced employment of regional anesthesia could not be determined, but it was shown that “sicker” patients were allocated to the regional group. It would be interesting if Dr. Sprung et al.  1 could add valuable data to this debate.
Patients with β-blocker therapy were more likely to experience PMI. 1 The authors speculated that this surprising finding was because intraoperative extremes of heart rate did not differ between groups. β Blockers have been shown to prevent PMI and improve long-term survival after noncardiac surgery. 6 However, it should be stressed that intraoperative and postoperative lower heart rates (below 80 beats/min) are the key to successful treatment with β blockers. This has been shown by Poldermans et al.  7 who evaluated the effect of bisoprolol in a group of patients with positive dobutamine echocardiography results who were scheduled to undergo major vascular surgery. In the bisoprolol group, 3.4% of patients died of cardiac causes, compared with 17% of patients in the standard care group (P  = 0.02). Nonfatal myocardial infarction occurred in 17% of patients given standard care only and in none of those to whom bisoprolol was administered (P  = 0.001). Mean heart rates in the bisoprolol group were significantly lower than in standard care patients. An accompanying editorial stated that it seems likely that the cumulative morbidity resulting from three sequential procedures (angiography, revascularization, major vascular procedure) would be higher than the 3.4% rate of major cardiac complications in bisoprolol patients. 8 
Recent percutaneous transluminal coronary angioplasty (PTCA) was not cardioprotective in regard to reinfarction rate; however, it significantly prevented death after PMI evolved. 1 The only patient with PTCA who died had undergone PTCA more than 12 months before surgery. These data are not in accordance with a study from Posner et al.  , 9 who demonstrated a significantly higher incidence of PMI after noncardiac surgery if PTCA was performed less than 3 months before surgery. Therefore, it would be interesting if Dr. Sprung et al.  1 could determine the exact time when PTCA was undertaken.
References
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