Radionuclide and angiographic evidence of right coronary artery spasm

Summary  Coronary artery spasm as a cause of coronary insufficiency is often difficult to diagnose. Myocardial perfusion imaging provides important information on segmental ischemia and LV systolic function. Combined noninvasive myocardial imaging and coronary angiography can offer complementary information on functional and anatomic evaluation of myocardial perfusion and coronary circulation. We thank Daniel Harold, CNMT, for his assistance processing the SPECT images.     

Single coronary artery with spasm

A single coronary artery is a rare and potentially serious anomaly. We present the case of a 54-year-old woman with chest pain predominantly at rest. A single coronary artery was demonstrated by 64-row multidetector computed tomography (CT) imaging, which is useful for the diagnosis and classification of coronary anomaly. In our case, no coronary artery stenosis was demonstrated on CT angiographic images, and totally occlusive coronary spasm was confirmed by intracoronary infusion of acetylcholine.     

Arteriographic demonstration of spontaneous right coronary artery spasm in a patient with Prinzmetal's angina.

Coronary artery spasm may occur spontaneously during coronary angiography in patients with clinically documented or suspected Prinzmetal's angina. In other patients with Prinzmetal's angina, the spasm can be provoked by the administration of ergonovine. A patient with spontaneous spasm of the right coronary artery during coronary angiography is reported and some considerations for diagnosis and therapy of this entity is offered. Although intraoperative spasm has been reported in the cardiology literature, no such case has been described in the radiology literature.     

The use of perfusion scintigraphy to differentiate proximal right coronary artery stenosis from distal right coronary artery stenosis in patients with inferior left ventricular ischaemia

OBJECTIVE: The identification of patients with a significant proximal right coronary artery (RCA) is of clinical relevance since it may direct diagnostic and therapeutic strategies. This study was performed to determine parameters of (201)Tl RV perfusion SPECT which can be used to discriminate between proximal and distal RCA stenosis in patients with inferior left ventricular (LV) ischaemia. In addition, feasibility and reproducibility of a new semi-quantitative method for the assessment of RV perfusion were evaluated. METHODS: Inferior LV ischaemia was due to a single distal RCA stenosis in 10 (group I) and proximal RCA stenosis in 27 patients (group II). Twenty patients with normal (201)Tl myocardial perfusion scintigraphy and low likelihood of cardiovascular disease were used as a reference (group III). RESULTS: RV (201)Tl stress uptake did not differ between the three groups. However, group II showed a significantly higher (201)Tl rest uptake indicating RV redistribution whereas in group I and III tracer washout was shown. Extent and severity of LV inferior ischaemia was not different between groups I and II. RV redistribution has a sensitivity of 0.74, a specificity of 0.80, and an overall agreement of 0.76 for detecting proximal RCA stenosis. The feasibility of the assessment of RV (201)Tl perfusion was 94%. Inter-observer and intra-observer coefficients of variation for RV (201)Tl perfusion assessment were 1.5 and 2.4%, respectively. CONCLUSION: RV (201)Tl perfusion scintigraphy is feasible and reproducible. RV (201)Tl redistribution can be used to discriminate between proximal and distal RCA stenosis in patients with inferior LV ischaemia.     

Ventricular fibrillation during right coronary arteriography with ioxaglate, iohexol and iopamidol in dogs

Radiograph contrast media (CM) are known to produce myocardial disturbances during cardiac angiography. The most severe electrical disturbance is ventricular fibrillation (VF). Previous studies using prolonged right coronary exposures have demonstrated a higher incidence of VF with dilute low sodium CM than with dilute CM containing more physiologic levels of sodium. In this study the incidence of VF was examined for more conventional concentrations of iopamidol, iohexol and ioxaglate and for sodium supplemented iohexol. The incidence of VF was determined during 25-second injections of contrast media into the canine right coronary artery at a rate of 0.4 mL/sec. Injections of iohexol and iopamidol at concentrations of 160, 240 and 320 mgI/mL produced significantly more VF (P less than .005, Fisher Exact Test) than meglumine/sodium ioxaglate or iohexol supplemented with 20 mM sodium chloride. The time required to produce a 50% incidence of VF with iohexol and iopamidol was significantly related to sodium concentration (r = .92, P less than .01).     

Concurrent dissections of ascending aorta and right coronary artery during primary coronary angioplasty

We present a case of dissection in ascending aorta (AA) accompanying dissection of the right coronary artery (RCA) during transfemoral primary coronary angioplasty (PCA) for acute inferior myocardial infarction (MI). To our best knowledge, this is the first case of dissection both in AA and RCA during angioplasty for acute MI. The dissection in RCA was caused by balloon inflation during PCA. Most probably, an angiographically invisible retro-dissection in RCA resulted in the dissection in AA. A computed tomography (CT) confirmed the diagnosis of aortic dissection that was restrained in AA. The patient was treated conservatively. Five days after the event, a control CT demonstrated that the false lumen in AA disappeared and the dissection was healed entirely.     

Failure of right precordial electrocardiography during stress testing to identify coronary artery disease

BACKGROUND: It has been reported that the use of right precordial leads results in the same diagnostic accuracy as thallium-201 exercise scintigraphy for the detection of coronary artery disease (CAD). The aim of this study was to evaluate the utility of right precordial leads in the detection of CAD. METHODS AND RESULTS: We evaluated 900 consecutive patients (514 men, 386 women) ranging in age from 39 to 84 years (mean +/- SD, 64 +/- 11 years). Seven hundred forty patients underwent treadmill exercise testing, and 160 underwent pharmacologic stress testing for the diagnosis of chest pain or dyspnea. All received either Tl-201 or technetium-99m sestamibi during stress. During stress testing, the ECG was recorded every minute with 12 limb and left precordial leads and 3 right precordial leads (V(3)R, V(4)R, and V(5)R). The electrocardiogram was considered positive when the ST segment was either elevated or depressed by at least 0.1 mV at 80 ms after the J point, and results were also compared with single photon emission computed tomography myocardial perfusion imaging results. Of the 900 patients, 158 had significant positive changes in the limb or left precordial leads. Only 4 patients had positive changes in the right precordial leads (Fisher exact test, P <.001). Of the patients who had positive electrocardiographic changes, 95 (60%) had abnormal myocardial perfusion scans, with 91 in patients with normal right precordial leads. All 4 patients with ischemic changes in the right precordial leads had abnormal scans, but the left leads were also positive. Three hundred seventy-three of 900 patients (41%) had abnormal scans with no electrocardiographic evidence of ischemia. CONCLUSIONS: Our experience is far different than that published and suggests that the use of right precordial leads during stress testing fails to provide the same diagnostic accuracy as either the standard left-sided electrocardiography or myocardial perfusion imaging for the detection of CAD.     

冠状动脉痉挛致心肌血流灌注降低：反向再分布的机制研究

目的 探讨冠状动脉痉挛患者核素心肌灌注显像反向再分布（RR）的机制.方法 选择双嘧达莫负荷201TI心肌灌注显像表现为RR且诊断为冠状动脉痉挛的患者26例（RR组）、无冠状动脉狭窄及RR者16例（对照组）,在冠状动脉造影术中重复双嘧达莫试验,测量并比较注射双嘧达莫前后RR相关、非RR相关血管和对照组相应血管的校正心肌梗死溶栓疗法（TIMI）血流帧计数（CTFC）和心肌血流灌注积分（TMPG）.统计学处理采用t检验、χ2检验及相关分析.结果 冠状动脉造影见RR相关血管僵硬,血流速度和心肌灌注明显低于非RR相关血管,且RR区域静态心肌灌注缺损与冠状动脉造影血流速度缓慢高度相关（r=0.79,t=10.18,P＜0.001） 而对照组的各支冠状动脉血流速度和心肌灌注无明显差异.RR相关血管注射双嘧达莫前后CTFC分别为（36±6）帧及（26±7）帧（t=4.15,P＜0.01） TMPG分别为（2.02±0.39）级和（2.92±0.12）级（t=2.25,P＜0.05） 非RR相关血管注射前后CTFC分别为（29±7）帧及（25±5）帧（t=2.31,P＜0.05） TMPG分别为（2.56±0.31）级和（2.96±0.06）级（t=2.17,P＜0.05） 而对照组注射双嘧达莫前后TCFC及TMPG均无明显变化（t=0.932及0.867,P均＞0.05）.结论 冠状动脉痉挛患者静息状态下RR相关血管及微血管处于轻度痉挛状态,导致血流速度及心肌灌注缓慢 而负荷状态下血管扩张,使血流速度和心肌灌注加快,因而呈现RR.     

冠状动脉痉挛致心肌血流灌注降低:反向再分布的机制研究

Objective To investigate the mechanism of reverse redistribution (RR) on dipyridamole 201Tl myocardial perfusion studies in the patients with coronary artery spasm. Methods Twenty-six patients with coronary artery spasm and presented as RR on dipyridamole 201Tl myocardial perfusion studies were enlisted as RR group, while other 16 patients with no coronary artery stenosis nor RR were enlisted as control group. Dipyridamole test was repeated during coronary angiography. Corrected thrombolysis in myocardial infarction (TIMI) frame count (CTFC) and TIMI myocardial perfusion grade (TMPG) were measured at RR related and non-RR related coronary arteries before and after dipyridamole infusion respectively.All of the data were analyzed by Student's t-test orχ2-test and correlation analysis. Results Coronary artery angiography showed slower blood flow and lower myocardial perfusion in RR related vessels when compared with non-RR related vessels in RR group, but there was no significant difference among the main coronary arteries in control group. The perfusion defects of RR area at rest were positively related to slowerblood velocity at corresponding coronary arteries ( r = 0.79, t = 10.18, P ＜ 0.001 ). In RR related vessels,CTFC were (36 ±6) frames and (26 ±7) frames (t =4.15, P ＜0.01 ), while TMPG were (2.02 ±0.39)grades and (2.92 ± 0.12) grades ( t = 2.25, P ＜ 0.05 ) before and after dipyridamole infusion, respectively.In non-RR related vessels, CTFC were (29 ±7) frames and (25 ±5) frames (t =2.31, P ＜0.05), while TMPG were (2.56 ± 0.31 ) grades and (2.96 ± 0.06) grades ( t = 2.17, P ＜ 0.05 ) before and after dipyridamole infusion, respectively. However, there were no significant changes of CTFC and TMPG before and after dipyridamole infusion in control group ( t = 0.932, 0.867, respectively, both P ＞ 0.05 ). Conclusion RR is related to the decreased blood flow and myocardial perfusion induced by coronary artery spasm at rest,which may be improved by stress test such as intravenous dipyridamole infusion.     

右冠状动脉-冠状静脉窦瘘1例

患者 男,52岁。反复胸闷、胸痛10余年,加重2年。多次动态心电图检查未见异常;无高血压、高血脂及糖尿病病史。 冠状动脉 CT 血管成像(CTA)检查：右冠状动脉增粗,近段直径约0.67 cm,右冠状动脉左室后支走行扭曲,最宽处直径约1.0 cm;心大静脉增粗,冠状静脉窦瘤样扩张,最大直径约1.7 cm,与右冠状动脉左室后支间可见交通,瘘口直径约0.6 cm (图1,2);左前降支中段长约0.3 cm 钙化斑块,管腔未见明显狭窄。冠状动脉 CTA 诊断：右冠状动脉-冠状静脉窦瘘。