Diagnostic Ability of Manual Calcification Length Assessment on Non-Electrocardiographically Gated Computed Tomography for Estimating the Presence of Coronary Artery Disease.

Background: Coronary artery calcification score (CACS) on electrocardiography (ECG)-gated computed tomography (CT) is used for risk stratification of atherosclerotic cardiovascular disease, which requires dedicated analytic software. In this study, we evaluated the diagnostic ability of manual calcification length assessment on non-ECG-gated CT for epicardial coronary artery disease (CAD). Methods: A total of 100 patients undergoing both non-ECG-gated plain CT scans with a slice interval of 1.25 mm and invasive coronary angiography were retrospectively included. We manually measured the length of the longest calcified lesions of coronary arteries on each branch. The relationship between the number of coronary arteries with the length of coronary calcium > 5, 10, or 15 mm and the presence of epicardial CAD on invasive angiography was evaluated. Standard CACS was also evaluated using established software. Results: Of 100 patients, 49 (49.0%) had significant epicardial CAD on angiography. The median standard CACS was 346 [7, 1965]. In both manual calcium assessment and standard CACS, the increase in calcium burden was progressively associated with the presence of epicardial CAD on angiography. The receiver operating characteristic curve analysis showed similar diagnostic abilities of the two diagnostic methods. The best cut-off values for CAD were 2, 1, and 1 for the number of vessels with calcium > 5, 10, and 15 mm, respectively. Overall, the diagnostic ability of manual calcium assessment was similar to that of standard CACS > 400. Conclusions: Manual assessment of coronary calcium length on non-ECG-gated plain CT provided similar diagnostic ability for the presence of significant epicardial CAD on invasive angiography, as compared to standard CACS.

Multicenter research of bleeding risk between prasugrel and clopidogrel in Japanese patients with coronary artery disease undergoing percutaneous coronary intervention.

Although it has been reported that prasugrel achieves stronger antiplatelet effect and fewer cardiovascular events compared to clopidogrel in Japanese patients, there are limited data comparing the safety between the 2 dose regimens. Data from 1031 consecutive patients with coronary artery disease undergoing PCI at 5 institutions from May 2014 to April 2016, who received aspirin plus either clopidogrel (619 patients) or prasugrel (412 patients), were retrospectively analyzed. The choice of clopidogrel or prasugrel was left to the operator's discretion. Adverse events were defined as a composite of bleeding, hepatopathy, leukopenia, thrombopenia, exanthema, and major adverse cardiovascular events (MACE). MACE was defined as a composite of cardiovascular death, nonfatal myocardial infarction, and nonfatal ischemic stroke. The average follow-up period was 143 days in the prasugrel group and 263 days in the clopidogrel group. Adverse events occurred in 34.5% of patients in the prasugrel group and in 28.6% in the clopidogrel group. Although the Kaplan-Meier curves showed lower survival rates from MACE, all-bleeding, major bleeding, minor bleeding, and adverse events, in the prasugrel group compared to the clopidogrel group (log rank test p = 0.009, p = 0.001, p = 0.012, p = 0.018, and p < 0.001, respectively), multivariate Cox-regression analyses determined prasugrel as a significant risk factor for all-bleeding, minor bleeding, and adverse events, but not for MACE and major bleeding events. Dual antiplatelet therapy with prasugrel was independently associated with minor bleeding events, but not with MACE and major bleeding events, compared to clopidogrel, after PCI in common clinical settings.

Feasibility and safety of outpatient cardiac catheterization with intracoronary acetylcholine provocation test.

Intracoronary acetylcholine (ACh) provocation test is useful to diagnose vasospastic angina. Although outpatient coronary angiography has been widely performed in current clinical settings, the feasibility and safety of ACh provocation test in outpatient services are unclear. A total of 323 patients, who electively underwent ACh provocation test in hospitalization and outpatient services, were included. Coronary angiography was performed after insertion of a temporary pacing electrode in the right ventricle. The positive diagnosis of intracoronary ACh provocation test was defined as total or subtotal coronary artery narrowing accompanied by chest pain and/or ischemic electrocardiographic changes. Cardiac complications defined as composite of death, ventricular fibrillation or sustained ventricular tachycardia, myocardial infarction, cardiogenic shock, and cardiac tamponade, were evaluated. There were 201 patients (62%) in the hospitalization group and 122 patients (38%) in the outpatient group. The incidence of positive ACh provocation test was similar between the 2 groups (47 vs. 54%, p = 0.21). Coronary angiography in the outpatient group was performed through the radial artery, mostly (98%) with a 4 F sheath. Venous access site was not significantly different between the 2 groups, and the sheath size was 5 F in all cases. There were 2 cases (1.0%) of cardiac complications in the hospitalization group, whereas 1 case (0.8%), which led to unexpected hospitalization, occurred in the outpatient group. In conclusion, intracoronary ACh provocation test for the diagnosis of vasospastic angina in outpatient services was feasible and safe in selected patients.

Relation between severity of myocardial bridge and vasospasm.

BACKGROUND: Myocardial bridge (MB) has been reported to induce cardiac complications including coronary vasospasm. Although MB has some anatomical and morphological variations, the association of these variations with vasospasm is unclear. The aim of this study was to investigate the relation between morphological severity of MB and vasospasm induced by acetylcholine (ACh) provocation test. METHODS: A total of 392 patients without coronary stent in the left anterior descending artery (LAD) undergoing intracoronary ACh provocation test were included. Angiographic coronary artery vasospasm was defined as total or subtotal occlusion induced by ACh provocation. MB was identified on coronary angiography as a milking effect. Total bridged length and maximum percent systolic compression of MB in the LAD were analyzed quantitatively. RESULTS: MBs in the LAD were identified in 140 patients (36%), mostly in the mid segment. Patients with MB in the LAD had greater number of provoked vasospasm in the LAD and positive ACh provocation test compared to those without. The bridged length positively correlated with percent systolic compression of MB (r=0.37, p<0.001). In the receiver operating characteristic curve analysis, both bridged length and percent systolic compression of MB significantly predicted the provoked LAD spasm (AUC 0.74, p<0.001, and AUC 0.68, p<0.001). Multivariate regression analysis demonstrated these factors as independent predictors for provoked LAD spasm. CONCLUSION: MB, especially morphologically severe MB, may induce greater coronary vasospasm.

Paroxysmal atrial fibrillation during intracoronary acetylcholine provocation test.

Intracoronary acetylcholine (ACh) provocation test is useful to diagnose vasospastic angina. However, paroxysmal atrial fibrillation (AF) often occurs during intracoronary ACh provocation test, leading to disabling symptoms. The aim of this study was to investigate the incidence and predictors of paroxysmal AF during the test. A total of 377 patients without persistent AF who underwent intracoronary ACh provocation test were included. Paroxysmal AF during ACh provocation test was defined as documented AF on electrocardiogram during the procedure. There were 31 patients (8%) with paroxysmal AF during the test. Of these, 11 (35%) required antiarrhythmic drugs, but none received electrical cardioversion. All of them recovered sinus rhythm within 48 h. At procedure, paroxysmal AF occurred mostly during provocation for the right coronary artery (RCA) rather than for the left coronary artery (LCA) (90 vs. 10%). Multivariate logistic regression analysis demonstrated that a history of paroxysmal AF (OR 4.38 CI 1.42-13.51, p = 0.01) and body mass index (OR 0.88 CI 0.78-0.99, p = 0.03) were independent predictors for occurrence of paroxysmal AF during intracoronary ACh provocation test. In conclusions, paroxysmal AF mostly occurs during ACh provocation test for the RCA, especially in patients with a history of paroxysmal AF and lower body mass index. It may be better to initially administer intracoronary ACh in the LCA when the provocation test is performed.

Feasibility of omitting provocation test with 50 µg of acetylcholine in left coronary artery.

According to the Japanese Circulation Society guideline of vasospastic angina, incremental doses of acetylcholine (ACh) are prescribed for coronary spasm provocation: 20 and 50 µg for the right coronary artery (RCA), and 20, 50 and 100 µg for the left coronary artery (LCA). However, provocation by low doses of ACh in patients with low vasoreactivity may be less needed, and the requirement of 50 µg of ACh for the LCA in these patients has not been evaluated. In the present study, patients who underwent ACh provocation test for both the RCA and LCA were included. The positive diagnosis of intracoronary ACh provocation test was defined as total or subtotal coronary artery narrowing (i.e., angiographic coronary artery spasm) accompanied by chest pain and/or ischemic electrocardiographic changes. Coronary artery constriction was visually evaluated and defined as coronary artery diameter reduction <25 or 25-90% in patients without angiographic coronary artery spasm by 20 µg of ACh in the LCA. There were 33 out of 249 patients (13%) with LCA spasm by 20 µg of ACh. In subjects without LCA spasm by 20 µg of ACh, patients with coronary constriction <25% (n = 101) by 20 µg of ACh in the LCA rarely showed coronary artery spasm induced by 50 µg of ACh in the LCA, in comparison to those with coronary constriction 25-90% (n = 115) (2.6 vs. 32.7%, p < 0.001). None of the patients with coronary constriction <25% by 20 µg of ACh in the LCA had cardiac complications associated with administration of ACh. In conclusion, omission of 50 µg of ACh in the LCA may be possible when there is little coronary artery constriction by 20 µg of ACh in the LCA during provocation test, leading to less contrast and shortens overall procedure time.

Predictive value of coronary artery dilation response to nitrate for a positive intracoronary acetylcholine provocation test.

BACKGROUND: Baseline coronary artery diameter and coronary artery dilation response to nitrate are associated with coronary vasoreactivity. OBJECTIVES: The present study investigated the predictive value of coronary artery tone for a positive intracoronary acetylcholine (ACh) provocation test. METHODS: A total of 197 patients who underwent an ACh provocation test in the right coronary artery were included. A positive ACh provocation test was defined as transient total or subtotal occlusion of a coronary artery with signs/symptoms of myocardial ischemia. The segment, from the ostium to the bifurcation, of the right coronary artery was analyzed quantitatively. Coronary artery dilation response to isosorbide dinitrate (ISDN) was defined as the mean lumen diameter after an intracoronary injection of ISDN divided by the diameter before administration of ACh (i.e. baseline coronary artery diameter). RESULTS: After the administration of ACh, 49 patients (24.9%) had a positive ACh provocation test. Smaller baseline right coronary artery diameter (2.35±0.45 vs. 2.73±0.48 mm, P<0.001) and greater right coronary artery dilation response to ISDN (1.34±0.12 vs. 1.15±0.11, P<0.001) were observed in patients with a positive ACh provocation test. The receiver operating characteristic curve for baseline coronary artery diameter poorly predicted the occurrence of a positive ACh provocation test (area under the curve 0.71). The predictive values of dilation response of the right coronary artery to ISDN for the occurrence of a positive ACh provocation test (area under the curve 0.87) was significantly better compared with that of baseline right coronary artery diameter (P<0.001). CONCLUSION: Coronary artery dilation response to nitrate is a more accurate predictor of a positive intracoronary ACh provocation test compared with baseline coronary artery diameter.

Intracoronary Acetylcholine Provocation Testing　- Omission of the 20-µg Dose Is Feasible in Patients Without Coronary Artery Spasm in the Other Coronary Artery.

BACKGROUND: Based on the Japanese Circulation Society guideline of vasospastic angina, incremental doses of acetylcholine (ACh) are prescribed for coronary spasm provocation: 20 and 50 µg for the right coronary artery (RCA), and 20, 50 and 100 µg for the left coronary artery (LCA). However, the requirement for each dose of ACh has not been fully evaluated. METHODS AND RESULTS: A total of 249 patients who underwent ACh provocation test for both the RCA and LCA were included. The positive diagnosis of intracoronary ACh provocation test was defined as total or subtotal coronary artery narrowing accompanied by chest pain and/or ischemic ECG changes. Positive ACh provocation test was observed in 116 patients (47%). Patients without vasospasm in the LCA had a lower incidence of vasospasm in the RCA induced by 20 µg of ACh compared with those with vasospasm in LCA (0.8% vs. 27.5%, P<0.001). Similarly, vasospasm in the LCA induced by 20 µg of ACh was observed less frequently in patients without than with vasospasm in the RCA (6.1% vs. 26.7%, P<0.001). In all patients without vasospasm in the other coronary artery, intracoronary administration of 50 µg of ACh was performed without any complications. CONCLUSIONS: Skipping the provocation test with 20 µg of ACh in patients without coronary artery spasm in the other coronary artery may be possible. (Circ J 2016; 80: 1820-1823).