Reperfusion injury risk factors

Ischemia reperfusion injury is a complex disorder associated with various cardiovascular and other risk factors mainly including Hypertension, hyperlipidemia, Diabetes, Insulin resistance, aging, and defects with coronary artery circulation. Although the exact mechanism about how these causes injuries are still not clear but studies have done so far best explains their role in mediating oxidative stress and endothelial cell dysfunctions, the two most important pathophysiological processes involved in the mediation of injury.

Risk factors for reperfusion injury include^[1]

• Hypertension with left ventricular hypertrophy,
• Congestive heart failure
• Increased age^[2],
• Diabetes, and
• Hyperlipidemia

It is important to identify the risk factors associated with worse reperfusion injury in STEMI patients. This may help in early risk stratification and develop therapeutic targets to reduce the infarct size associated with reperfusion injury. These risk factors also increase the risk of a first cardiac event and emphasize the importance of secondary prevention. Most of these associations are based on animal studies and includes:

• Left Ventricular hypertrophy:
  • Long-standing hypertension leads to pressure overload hypertrophy. This is associated with metabolic and biochemical changes, predisposing the myocardium to severe reperfusion injury.
  • Moreover, an increase in lactate dehydrogenase and creatine kinase release after reperfusion increases the susceptibility of the hypertrophied heart to ischemia/reperfusion injury.
• Heart failure: Left ventricular dysfunction may predispose the heart to reperfusion injury.
• Age: Aging is associated with^[3]
  • Oxidative stress as well as
  • Impaired systolic and diastolic function,Both the mech. increases the risk related to reperfusion injury.

• Diabetes: The data from preclinical studies in diabetic patients is not clear, however, there is clearly increased susceptibility of the heart to ischemic stress and possibly reperfusion.
• Hyperlipidemia: Hyperlipidemia is a known risk factor for ischemic heart disease.
  • Animal and human studies have shown that the presence of hyperlipidemia increases the risk of reperfusion injury and may also attenuate the protective effect of ischemic preconditioning.