Hand Grip Strength and Myocardial Oxygen Consumption Index among Coronary Artery Bypass Grafting Patients

BACKGROUND Hand grip strength (HGS) is a reliable indicator of peripheral muscle strength. Although, numerous studies have investigated the strength of hand grip; little attention has been given to coronary artery disease (CAD) patients, exploring the relationship between HGS and myocardial oxygen consumption (MVO2) index. The current study aimed to evaluate the interaction between HGS and MVO2 index findings before and after cardiac surgery. METHODS Twenty-seven patients with CAD had HGS were assessed using handheld dynamometer. HGS for each hand were documented. MVO2 index was assessed using rate pressure product (RPP), which is the product of the heart rate (HR) and systolic blood pressure (SBP). Repeated measures MANOVA were carried out to estimate the interaction between both hands HGS and MVO2 index before and after surgery. RESULTS There was significant interactions (P<0.001) for both HGS dominant and non-dominant with large effect sizes (HGS dominant×MVO2 index: hp (2)=0.44; HGS dominant×RPP: hp (2)=0.49). This signifies that peripheral muscle strength of the upper limb (HGS dominant and non-dominant) had different effects on MVO2 index before and after surgery. The interaction graph shows that the increase in MVO2 index after surgery was significantly greater for peripheral muscle strength of the dominant hand when compared to non-dominant. CONCLUSION Patients with CAD had interactions between HGS and oxygen consumption before and after surgery. Hence, HGS might be used as a predictor to assess oxygen consumption among cardiac patients.