Non-Pharmacological Interventions in Refractory Angina.
Refractory angina (RA) is a chronic condition characterised by persistent anginal symptoms despite optimal medical therapy (OMT) and revascularisation. In order to fulfil the conventional
definition of this disorder, arterial insufficiency in the setting of coronary artery disease (CAD) needs to be demonstrated, and reversible myocardial ischaemia should be clinically established as the cause of the symptoms.
Although, definitive data pertaining to the prevalence of RA is scarce, there is a general recognition that it is a growing problem, and one that results in significant public health burden. Moreover, patients may develop a maladaptive psychological response to their disorder, with heightened and dysregulated perception of their symptoms.
More novel agents are also available, including ivabradine and ranolazine. Ivabradine
specifically inhibits hyperpolarisation-activated cyclic nucleotidegated (HCN) channels, thereby decreasing the ‘funny’ pacemaker current (If) within the sinoatrial node. The effect is anantianginal
action via reduction in HR, but with no effect on inotropy, vascular resistance or blood pressure. Meanwhile, ranolazine achieves its effects on myocytes via inhibition of the late phase of the inward
sodium current during Phase 0 of action potentials. This is thought to reduce ventricular stiffness during diastole and hence improve coronary perfusion.
Pressure cuffs are wrapped around the lower limbs of patients and inflated at the onset of diastole. The resulting increase indiastolic blood pressure has the effect of improving coronary perfusion pressure during diastole. The rapid deflation of the cuffs at the onset of systole also serves to reduce vascular resistance, causing a reduction in cardiac workload.22 The combined effect is analogous to that of an intra-aortic balloon pump (IABP), albeit in a non-invasive fashion.
Heart Res Open J. 2018; 5(1): 1-7. doi: 10.17140/HROJ-5-146
