August 11, 2005

Perioperative Myocardial Ischemic Injury: Incidence and Resource Utilization In A Prospective Clinical Trial

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William C Mackey¹, Lee A. Fleisher², Seema Haider³, Sairah Sheikh³, Joseph C. Cappelleri⁴, Won Chan Lee⁵, Qin Wang⁶, Jenny Stephens^7
1Tufts New England Medical Center, Boston, MA;²University of Pennsylvania, Philadelphia, PA;³Pfizer Inc, New London, CT;⁴Pfizer Inc, Groton, CT;⁵Abt Associates, Clinical Trials, Bethesda, MD;⁶Abt Associates, Clinical Trials, Bethesda, MD;⁷PharMerit International, Bethesda, MD

Introduction and Objectives:
In this study we prospectively assess the health care resource utilization and cost associated with perioperative myocardial ischemic injury (PMII) in high risk patients undergoing vascular surgery.
Methods:
Two hundred and thirty six patients consented to participate in a pharmacoeconomic substudy as a part of a randomized, multi-center clinical trial. Patients were assessed for PMII using clinical, biochemical, and ECG criteria. PMII was defined as fatal or non-fatal myocardial infarction (MI), new or worsened congestive heart failure (CHF), or new arrhythmias (ARH). Resource utilization parameters for patients with and without PMII were compared. Patients underwent the following index procedures: open AAA repair 44, bypass for aortoiliac disease 29, bypass for femoropopliteal disease 62, bypass for femorotibial disease 71, extra-anatomic bypass 23, and miscellaneous procedures 7.
Results:
Mortality was 3.4% (8/236), and 7/8 deaths were related to PMII. PMII occurred in 42/236 (17.8%) patients: 22 MI, 11 CHF, 12 ARH (3 subjects suffered 2 PMII events). There were no differences in the incidence of PMII related to the different index procedures. PMII was associated with an increase in resource utilization as shown below:

	N	LOS>30 Day (%)	Mean LOS (SD)	# In ICU (%)	Mean ICULOS (SD)	#ER Visit (%)
PMII	42	6 (14.3)	16.8 (8.9)	35 (83.3)	6.6 (6.3)	10 (23.8)
No PMII	194	3 (1.5)	10.0 (6.4)	121 (62.4)	3.7 (3.7)	20 (10.3)
P Value		<.001	<.001	<.009	<.009	<.02

LOS= Length of Stay; # in ICU = # patients requiring ICU care; ICULOS = ICU length of stay; # ER Visit = # patients returning to ER for care after discharge.
The increase in resource utilization associated with PMII resulted in a mean incremental cost per patient of $9,300.00

Conclusions:
In modern vascular surgery practice PMII remains common despite the availability of beta-blockers, statins, and other preventative measures. PMII is associated with increases in resource utilization and cost. If 250,000 open vascular procedures are performed annually in high risk patients, the cost of PMII in these patients alone exceeds 400 million dollars. Strategies to prevent PMII should be evaluated in large scale prospective trials.