Clinical Usefulness, Angiographic Characteristics and Safety Evaluation of Intracoronary Acetylcholine Provocation Testing Among 921 Consecutive Caucasian Patients With Unobstructed Coronary Arteries

Study Questions:

What are the clinical usefulness, angiographic characteristics, and safety of the acetylcholine administration (ACH-test) in Caucasian patients with unobstructed coronaries?

Methods:

From September 2007-June 2010, 921 consecutive patients (362 men, mean age 62 ± 12 years) 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. Multiple logistic regression analysis was performed using forward variable selection based on likelihood ratios to identify predictors for a pathologic ACH-test, and for identification of patients with epicardial compared to those with microvascular spasm.

Results:

Three-hundred forty-six patients (35%) complained of chest pain at rest, 222 (22%) of chest pain upon exertion, 238 (24%) of 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 electrocardiogram [ECG] shifts) was 33.4%, and of microvascular spasm (angina and ischemic ECG shifts without epicardial spasm) was 24.2%. Epicardial spasm was most often diffuse and located in the distal coronary segments (p < 0.01). No fatal or irreversible nonfatal complications occurred. However, nine patients (1%) had minor complications (nonsustained ventricular tachycardia [n = 1], fast paroxysmal atrial fibrillation [n = 1], symptomatic bradycardia [n = 6], and catheter-induced spasm [n = 1]).

Conclusions:

The authors concluded that the ACH-test is a safe technique to assess coronary vasomotor function.

Perspective:

This study reports a high frequency of coronary microvascular spasm in a large contemporary cohort of Caucasian patients with anginal symptoms and unobstructed coronary arteries. The study further suggests that the ACH-test is a safe technique to assess coronary vasomotor function. Overall, the role for routine provocative testing is uncertain, as it is unlikely to change clinical practice in most patients with coronary artery disease. Its value probably lies in a smaller group of patients with nonobstructive disease and recalcitrant symptoms or unexplained sudden cardiac death. Although the risks of the procedure are small, they are potentially higher in patients with left main disease, multivessel disease, severe left ventricular dysfunction, or incipient heart failure, and testing should be used cautiously in these individuals.

Clinical Topics: Acute Coronary Syndromes, Arrhythmias and Clinical EP, Heart Failure and Cardiomyopathies, Invasive Cardiovascular Angiography and Intervention, Noninvasive Imaging, Stable Ischemic Heart Disease, Implantable Devices, SCD/Ventricular Arrhythmias, Acute Heart Failure, Interventions and ACS, Interventions and Coronary Artery Disease, Interventions and Imaging, Angiography, Nuclear Imaging, Chronic Angina

Keywords: Coronary Artery Disease, Acute Coronary Syndrome, Myocardial Ischemia, Multivariate Analysis, Coronary Circulation, Electrocardiography, Constriction, Pathologic, Angioplasty, Balloon, Coronary, Coronary Vasospasm, Tachycardia, Ventricular, Coronary Angiography, Chest Pain, Heart Failure, Bradycardia, Coronary Vessels, Ventricular Dysfunction, Left, Death, Sudden, Cardiac, Logistic Models, Troponin


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