Article Text
Statistics from Altmetric.com
Despite the wealth of treatments available for the management of angina pectoris, a significant proportion of patients remain refractory. These patients seem to be survivors, so that an individual with refractory angina may suffer with it for many years; consequently patients with refractory angina pectoris usually require multiple admissions, often to expensive cardiac units.1 Recently transmyocardial laser revascularisation (TMLR) has enjoyed considerable world wide popularity as a potential treatment strategy. However, the recently published TMLR trial from Papworth Hospital led the investigators to conclude that they cannot advocate the adoption of TMLR for the management of refractory angina.2 Neurostimulation presents an alternative treatment strategy for which efficacy data continues to grow, although there has not yet been a large randomised controlled trial into its use in the treatment of refractory angina.
This article summarises neurostimulation research to date and reviews the current theories on the mechanisms of action.
Development of neurostimulation for refractory angina
Neurostimulation was developed in response to the gate theory of pain transmission to provide a non-pharmacological method of providing pain relief.3 Despite initial excitement, the effects were found to be variable. In the case of peripheral vascular disease, neurostimulation in the form of transcutaneous electrical nerve stimulation (TENS) and spinal cord stimulation (SCS) was found to be particularly useful.4 As well as providing pain relief, neurostimulation also improved microcirculatory blood flow, and led to ischaemic ulcer healing.
In response to the work in peripheral vascular disease, other workers began to look for a similar effect in different ischaemic conditions, with Mannheimer and colleagues first reporting the success of TENS in patients with chronic intractable angina pectoris.5 They showed that TENS not only reduced patients' symptoms, but also increased the myocardium's threshold for ischaemia.6 The technique was applied clinically only in patients where medical and surgical treatment …