Association of Hematological Indices with the Degree of Microvascular Injury in Patients with Acute Anterior Wall Myocardial Infarction Treated With Primary Percutaneous Coronary Intervention

Murat Sezer ^1*, Irem Okcular ¹, Taner Goren ¹, Huseyin Oflaz ¹, Yilmaz Nisanci ¹, Berrin Umman ¹, Fehmi Mercanoglu ¹, Ahmet K Bilge ¹, Mehmet Meric ¹ and Sabahattin Umman ¹

¹ Istanbul University, Turkey

^* To whom correspondence should be addressed. E-mail: sezerm{at}istanbul.edu.tr.

Accepted 21 July 2006

Abstract

Background In acute myocardial infarction (AMI), elevated neutrophil count has been associated with more severe coronary artery disease and larger infarct size. Elevated mean platelet volume (MPV) is also associated with poor clinical outcome and impaired angiographic reperfusion in patients with AMI. But, the associations of neutrophil count and MPV with the indices of tissue level reperfusion were not fully elucidated. The goal of this study was to elucidate the relation between baseline neutrophil count and MPV on presentation and microvascular injury in patients with anterior AMI treated with primary percutaneous coronary intervention (pPCI).

Methods Forty-one patients with anterior wall AMI treated successfully with pPCI were included. The WBC count, neutrophil count and MPV were obtained on admission and the percentage of neutrophils was calculated. Following PCI, TIMI grade 3 flow was established in all patients. We examined the coronary flow velocity pattern (diastolic deceleration time: DDT) with transthoracic echocardiography and measured intracoronary pressures with fiberoptic pressure - temperature sensor tipped guide wire in the LAD within 48 hours following PCI. Thermodilution derived coronary flow reserve (CFR) was calculated. Index of microvascular resistance (IMR) was defined as simultaneously measured distal coronary pressure divided by the inverse of the thermodilution derived hyperemic mean transit time. Subsequently, a short compliant balloon was placed in the stented segment and inflated to measure coronary wedge pressure (CWP).

Results Higher neutrophil count(s) (were) strongly associated with higher IMR (r= 0.86, p<0.001), lower CFR (r= -0.60, p<0.001), shorter DDT (r= -0.73, p<0.001) and higher CWP (r= 0.73, p<0.001). Likewise, there were significant correlations among the percentage of neutrophils and CFR (r= -0.34, p=0.02), IMR (r= 0.46, p=0.002), DDT (r= - 0.36, p=0.01) and CWP (r= 0.49, p=0.001). Relations among WBC count and IMR (r: 0.38, p= 0.01), CFR (r: -0.33, p: 0.03), DDT (r: -0.36, p= 0.01), and CWP (r= 0.32, p= 0.026) were slightly significant. Higher neutrophil count remained independently associated with indices of microvascular perfusion in multivariable models controlling for age, smoking habits and time to treatment. Also, higher MPV on admission was strongly associated with higher IMR (r: 0.89, p<0.001), steeper DDT (r:-0.64, p<0.001), lower CFR (r: -0.43, p= 0.004) and higher CWP (r= 0.77, p<0.001)

Conclusion Absolute and relative neutrophilia and higher MPV on admission were independently associated with impaired microvascular perfusion in patients with anterior AMI treated with p-PCI. It is possible that neutrophilia and high MPV are simple surrogate markers of worse microvascular injury in patients with AMI.

Keywords: Acute myocardial infacrtion, Microvascular injury, Neutrophil, Platelets, Primary percutaneous intervention

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