Does a negative ergonovine provocation test truly predict freedom from variant angina?

Feasibility of right coronary artery first ergonovine provocation test

BACKGROUND

Intracoronary (IC) provocation angiography is recommended when variant angina is suspected. However, specific procedure-related factors remain uncertain.

METHODS

Intracoronary ergonovine infusion was used for the provocation test. About 10, 20, and 40 μg of ergonovine were sequentially injected into the right coronary artery (RCA). During a negative or intermediate response or depending on the clinician's discretion, the left coronary artery (LCA) was injected with incremental doses of 20, 40, and 80 μg of ergonovine or vice versa. If significant coronary spasm or positive clinical findings were noted, the test was stopped immediately and IC nitroglycerine was injected.

RESULTS

We reviewed a total of 725 patients (male: 402; mean age: 58.5 years). Spasm-positive response was observed in 269 patients (37.1%), intermediate response in 113 patients (15.6%), and negative response in 343 patients (47.3%). The right radial artery approach was used in most cases (92.6%), and the RCA first approach was mainly chosen (95.0%). The provocation results in the RCA and LCA (93.4%, 381/408) were highly consistent, and the clinically significant discrepancy rate (RCA positive/LCA negative or RCA negative/LCA positive) was 1.5% (6/408). The RCA-alone provocation test can identify spasm-positive response in 93.4% of the patients (228/244). The mean procedure time was 39.9 ± 11.0 min, and approximately 3.3% (24/725) of the patients developed acute complications.

CONCLUSIONS

The RCA-first IC ergonovine provocation test is feasible, and the RCA-alone spasm provocation could be acceptable except in an intermediate response, highly clinically suspected cases, or high-risk patients.

Myocardial infarction with non-obstructive coronary arteries: a focus on vasospastic angina

Vasospastic angina (VSA) is considered a broad diagnostic category including documented spontaneous episodes of angina pectoris produced by coronary epicardial vasospasm as well as those induced during provocative coronary vasospasm testing and coronary microvascular dysfunction due to microvascular spasm. The hallmark feature of VSA is rest angina, which promptly responds to short-acting nitrates; however, VSA can present with a great variety of symptoms, ranging from stable angina to acute coronary syndrome and even ventricular arrhythmia. VSA is more prevalent in females, who can present with symptoms different from those among male patients. This may lead to an underestimation of cardiac causes of chest-related symptoms in female patients, in particular if the coronary angiogram (CAG) is normal. Evaluation for the diagnosis of VSA includes standard 12-lead ECG during the attack, Holter monitoring, exercise testing, and echocardiography. Patients suspected of having VSA with a normal CAG without a clear myocardial or non-cardiac cause are candidates for provocative coronary vasospasm testing. The gold standard method for provocative coronary vasospasm testing involves the administration of a provocative drug during CAG while monitoring patient symptoms, ECG and documentation of the coronary artery. Treatment of VSA consists of lifestyle adaptations and pharmacotherapy with calcium channel blockers and nitrates.

Provocative testing for coronary reactivity and spasm

Coronary spasm is an important and often overlooked etiology of chest pain. Although coronary spasm, or Prinzmetal's angina, has been thought of as benign, contemporary studies have shown serious associated adverse outcomes, including acute coronary syndrome, arrhythmia, and death. Definitive diagnosis of coronary spasm can at times be difficult, given the transience of symptoms. Numerous agents have been historically described for provocative testing. We provide a review of published data for the role of provocation testing in the diagnosis of coronary spasm.