Use of Shock Wave Therapy for Neo-Vascularisation in Non-critical Coronary Artery Disease: Validation by Quantitative Cardiac MRI Perfusion

In 2017 a systematic review of extracorporeal shock wave therapy (ESWT) in the treatment of coronary artery disease was undertaken by Berneikaite G. et al. to perform meta-analysis regarding anti-anginal efficacy of Cardiac ESWT (CSWT). The review identified 39 studies encompassing 1,189 patients with 1006 patients treated by CSWT. The meta-analysis found all selected studies demonstrated significant improvement in subjective measures of angina symptoms and/or quality of life, while the majority of studies also found improvement in left ventricular function and myocardial perfusion. For myocardial perfusion, SPECT was employed in 27 of 32 studies and PET in 2 of 4 studies. Cassar et al compared myocardial segments that were treated with CSWT and those segments that were not, finding after 4 months of follow-up that the progression of Ischaemic burden of untreated segments was significantly greater. As Cardiac MRI has not been employed to monitor myocardial perfusion in these studies, and with the increasing number of reports demonstrating the usefulness of MRI in characterising ischaemia, it seems opportune to utilise this non-radioactive technology to study the beneficial effect of CSWT in non-critical Coronary artery cases who have been found to have serially increasing coronary plaque burden. It has been shown that efficacious Statin usage can progressively regress coronary plaque volume, so augmenting collateral flow at stenotic coronary sites would buy time for Statin usage to complete this regression for definitive cure of CAD. With the availability of MRI methods to quantify myocardial perfusion accurately, the efficacy of CSWT for Neovascularization can thus be effectively documented as numerical data using Quantitative Cardiac MRI Perfusion, accompanied by Bull's eye views for ease of visual appreciation.

Inclusion criteria

• Patients with symptoms of coronary artery disease
• Patients without obstructive coronary artery disease
• with LVEF not < 40%.

Exclusion criteria

• Age < 18 years,
• Pregnancy or lactation.
• Contraindication to contrast enhanced stress Cardiac Magnetic Resonance (eg. Estimated GFR <30ml/min/1.73m2, severe allergy to gadolinium based contrast agent, contraindication to adenosine)
• Life expectancy <24 months
• Haemodynamically unstable
• Participation in other clinical trial within 6 months of enrollment.
• Recent myocardial infarction within 6 months.
• Unable to consent to or perform components of the study.