Variant angina associated with coronary artery endothelial dysfunction and myocardial bridge: a case report and review of the literature

Worsening of Angina Following Nitroglycerin Administration: A Case Report of the Interplay With Undiagnosed Myocardial Bridge

Myocardial bridge (MB) is a congenital abnormality where part of a coronary epicardial artery runs under the myocardium fibers and is compressed in systole; this becomes more pronounced when nitroglycerin (NTG) is administered. In this report, we describe the case of a 40-year-old African American man who presented with chest pain that did not respond to NTG or isosorbide mononitrate and was only partially relieved by narcotics. His past medical history was significant for coronary artery disease (CAD) with a stent into the left anterior descending artery (LAD) several months prior, hypertension, hyperlipidemia, paroxysmal atrial fibrillation, sick sinus syndrome, permanent pacemaker, pulmonary embolism, and cerebral vascular accident. No explanation for his angina was found either in the previous outpatient left heart catheterization (LHC) procedures demonstrating LAD stent patency or initial chest pain workup upon admission. Functional LHC procedure with adenosine infusion and acetylcholine provocation demonstrated endothelial dysfunction with notable epicardial spasm and MB of the LAD that worsened with NTG. Cardiology advised dual antiplatelet therapy and a statin as part of treatment for CAD and a calcium channel blocker with a bradycardic effect (e.g., diltiazem, verapamil) for the MB and coronary vasospasm, and avoidance of NTG and long-acting nitrates (e.g., isosorbide mononitrate), which can cause reflex tachycardia and worsen angina from MB. A selective serotonin reuptake inhibitor was added for increased cardiac nociception. The patient's pain resolved, and he was discharged. MB is an important alternate etiology to consider when chest pain does not respond to NTG administration for adjustment of treatment modalities. The initial treatment for this patient's pain with NTG likely exacerbated symptoms by reducing intrinsic coronary wall tension and subsequently increasing reflex sympathetic stimulation of contractility of the left ventricular myocardium, which can, in turn, increase anginal symptoms and ischemia.

The Outcome of Percutaneous Coronary Intervention for Significant Atherosclerotic Lesions in Segment Proximal to Myocardial Bridge at Left Anterior Descending Coronary Artery

This study aimed to evaluate the efficacy of percutaneous coronary intervention (PCI) for significant atherosclerosis lesions proximal to myocardial bridge (MB) at left anterior descending coronary artery (LAD).A total of 330 consecutive patients with LAD significant stenosis, diagnosed as acute coronary syndrome (ACS), were included. Based on whether combined with MB, the patients were divided into the MB group (MB, n = 48) and non-MB group (NMB, n = 282). Drug eluting stents (DES) were successfully implanted in the stenostic segments prior to MB. All patients were followed up during the hospital stay, 30 days and 12 months after PCI, to evaluate the major adverse cardiac events (MACEs).There was no difference in the incidence of MACEs between the two groups (6.2% versus 2.1%, P = 0.254) when in the hospital. During the follow-up of 30 days and 12 months after PCI, the rate of MACEs was significantly higher in the MB group than in the NMB group (18.2% versus 6.4% and 43.8% versus 17.0%, respectively, P < 0.001). Stent restenosis occurred in four patients in the MB group; whereas, in five patients in the NMB group, the rate of stent restenosis was higher in the MB group than in the NMB group (8.3% versus 1.8%, P = 0.036). Cox proportional hazards regression analysis revealed that the presence of MB was an independent predictor of MACEs (hazard ratio (HR) = 1.781, 95% confidence intervals (95% CI) = 1.108-2.863, P = 0.017).DES implantation for significant atherosclerosis stenosis in the segments proximal to MB have higher incidence of MACEs. MB appears to be associated with a higher incidence of stent restenosis after PCI and is a significant factor in the occurrence of MACEs.

A potential protective element of myocardial bridge against severe obstructive atherosclerosis in the whole coronary system

BACKGROUND

Myocardial bridge (MB) is generally described as a congenital benign variation. Previous studies have suggested that MB prevents atherosclerotic plaques from accumulating within the bridge segment but promotes coronary stenosis in the proximal segment adjacent to MB. However, it is still not clear whether MB has positive or negative effects on severe obstructive atherosclerosis in the whole coronary artery system.

METHODS

In this study, 6774 patients with symptoms of angina who were clinically diagnosed coronary artery disease (CAD) or suspected CAD underwent coronary angiography (CAG) in our center. The presence of MB was diagnosed, and a retrospective analysis was performed between MB and severe obstructive CAD requiring percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG) in the whole coronary system.

RESULTS

Among 6774 patients, 3583 (52.89%) were diagnosed with severe obstructive CAD (SOCAD) requiring a treatment of PCI or CABG and enrolled into the SOCAD group; and 3191 (47.11%) without SOCAD into the non-SOCAD group. Non-SOCAD and SOCAD groups had 512(16.05%) and 66(1.84%) patients with MB, respectively (P <  0.0001). The rate of SOCAD requiring PCI or CABG in patients with MB was much lower than that in patients without MB (11.42% vs. 56.76%, P <  0.0001). After adjusting for sex, age, diabetes mellitus, hypertension, and other risk factors, MB still had some positive role in preventing severe obstructive CAD (log-OR = - 2.134, p-value < 0.0001) through logistic regression.

CONCLUSIONS

Our results provided a clue that MB might act as a potential protective element against severe obstructive atherosclerosis in the whole coronary artery system.

Prinzmetal Angina in a Young Patient with Essential Thrombocythemia, After Anagrelide Initiation - Case Report and Literature Review

We report a case of Prinzmetal angina as inaugural manifestation of coronary disease, in a young adult male patient, recently started on anagrelide for essential thrombocythemia. Moderate proximal left anterior descendent coronary artery stenosis was documented by angiography, and interventional or surgical revascularization has been discussed. Patient’s option was for medical therapy alone. Anagrelide was temporarily withdrawn and rechallenged uneventfully after a couple of months and clinical evolution is good at four years follow-up. The mechanism by which anagrelide could induce coronary spasm and ischemia remains to be clarified.

Myocardial bridges: Overview of diagnosis and management

A myocardial bridge is a segment of a coronary artery that travels into the myocardium instead of the normal epicardial course. Although it is general perception that myocardial bridges are normal variants, patients with myocardial bridges can present with symptoms, such as exertional chest pain, that cannot be explained by a secondary etiology. Such patients may benefit from individualized medical/surgical therapy. This article describes the prevalence, clinical presentation, classification, evaluation, and management of children and adults with symptomatic myocardial bridges.

Late gadolinium enhancement on cardiac magnetic resonance predicts coronary vasomotor abnormality and myocardial lactate production in patients with chronic heart failure

Myocardial fibrosis and microvascular dysfunction are key determinants of outcome in heart failure (HF); we examined their relationship in patients with HF. Our study included 61 consecutive patients with HF but without coronary stenosis. All underwent gadolinium-enhanced cardiac magnetic resonance to evaluate late gadolinium enhancement (LGE) and an acetylcholine (ACh) provocation test to evaluate microvascular dysfunction. During the ACh provocation test, we sampled blood simultaneously from the coronary sinus and aortic root to compare lactate concentrations. We quantified coronary blood flow volume using an intracoronary Doppler-tipped guidewire. We detected LGE in 34 patients (LGE-positive); 27 were LGE-negative. Coronary blood flow volume increased significantly after the ACh provocation test only in LGE-negative patients (before vs. after ACh, 47.5 ± 36.8 vs. 69.2 ± 48.0 ml/min, respectively; p = 0.004). The myocardial lactate extraction ratio (LER) significantly decreased after the ACh test in both groups (LGE-negative, p = 0.001; LGE-positive, p < 0.001), significantly more so in the LGE-positive group (p = 0.017). Multivariate logistic regression analysis showed that a post-ACh LER < 0 (indicating myocardial lactate production) was a significant predictor of LGE-positivity (odds ratio 4.54; 95 % confidence interval 1.38-14.93; p = 0.013). In the LGE-positive group, an LGE volume greater than the median significantly predicted a post-ACh LER of <0 (p = 0.042; odds ratio 6.02; 95 % confidence interval 1.07-33.86). ACh-provoked coronary vasomotor abnormality is closely correlated with myocardial fibrosis in patients with HF but without organic coronary stenosis. Coronary vasomotor abnormalities in fibrotic myocardium may worsen HF.

Significant Response to Lower Acetylcholine Dose Is Associated with Worse Clinical and Angiographic Characteristics in Patients with Vasospastic Angina

Background and Objectives

Subjects and Methods

Results

Conclusion