Efficacy of Endothelin Receptor Antagonism in Coronary Artery Spasm

Inclusion criteria

• Definitive diagnosis of epicardial vasospasm on maximal acetylcholine dose of 100µg (at iCFT)
• At least 18 years of age
• On optimal regular care ( current or previous treatment with at least 2 daily anti-anginal medicines i.e. nitrate and calcium channel blocker
• Continuing episodes of angina(-like) complaints at least once weekly despite 3.
• Signed online informed consent for participation in NL-CFT registry (the Netherlands Registry of invasive coronary vasomotor function testing), or willing to co-sign for registry at time of inclusion in EDIT-CAS
• Written informed consent for EDIT-CAS

Exclusion criteria

• Systolic blood pressure (SBP) <85 mmHg measured at Visit 1
• Significant hepatic impairment at time of iCFT lab (ASAT/ALAT >3x upper limit of normal (ULN)) or history of liver cirrhosis (Child-Pugh 7-15)
• Severe anemia (Hb<6.0mmol/L) without identified cause at time of inclusion
• Patients with limited life expectancy (<1 year)
• Participation in another randomized clinical study with an use of an Investigational Medicinal Product (IMP) up to one month prior to enrolment.
• Pregnancy, active desire to become pregnant or unwilling to take adequate* contraceptive measures when of child bearing potential for the duration of 6 months (active medication period + 3 months safety).
• Known heart failure with reduced ejection fraction<35%
• Known pulmonary hypertension of any type
• Potentially dangerous interaction due to the use of another CYP3A4 or CYP2C9 substrate (e.g. ciclosporin A, glibenclamide, fluconazole, rifampicin, tacrolimus/sirolimus, lopinavir/ritonavir)
• Repeat spasm provocation test deemed unsafe (e.g. allergic reaction at iCFT)

• Adequate in this case meaning if on hormonal contraceptives, additional measures to be taken (e.g. condom).