Clinical Usefulness, Angiographic Characteristics and Safety Evaluation of Intracoronary Acetylcholine Provocation Testing Among 921 Consecutive Caucasian Patients with Unobstructed Coronary Arteries
Background—Coronary spasm can cause myocardial ischemia and angina in patients with and those without obstructive coronary artery disease. However, provocation tests using intracoronary acetylcholine administration (ACH-test) are rarely performed in clinical routine in the US and Europe. Thus, we assessed the clinical usefulness, angiographic characteristics and safety of the ACH-test in Caucasian patients with unobstructed coronaries.
Methods and Results—From September 2007-June 2010, a total of 921 consecutive patients (362 men, mean age 62±12years) who underwent diagnostic angiography for suspected myocardial ischemia and were found to have unobstructed coronaries (no stenosis ≥50%) were enrolled. The ACH-test was performed directly after angiography according to a standardized protocol. Three-hundred-forty-six patients (35%) complained chest pain at rest, 222 (22%) chest pain upon exertion, 238 (24%) a combination of effort and resting chest pain and 41 (4%) presented with troponin positive acute coronary syndrome. The overall frequency of epicardial spasm (>75% diameter reduction with angina and ischemic ECG-shifts) was 33.4% and of microvascular spasm (angina and ischemic ECG-shifts without epicardial spasm) 24.2%. Epicardial spasm was most often diffuse and located in the distal coronary segments (p<0.01). No fatal or irreversible non-fatal complications occurred. However, 9 patients (1%) had minor complications [non-sustained ventricular tachycardia (n=1), fast paroxysmal atrial fibrillation (n=1), symptomatic bradycardia (n=6), catheter-induced spasm (n=1)].
Conclusions—Epicardial and microvascular spasm are frequently found in Caucasians with unobstructed coronaries. Epicardial spasm is most often diffuse and located in the distal coronary segments. The ACH-test is a safe technique to assess coronary vasomotor function.
- Received May 28, 2013.
- Revision received January 23, 2014.
- Accepted January 28, 2014.