A myocardial bridge (MB) is an anatomical variant in which the myocardial muscle partially covers the epicardial coronary arteries, in particular, the left anterior descending coronary artery (LAD). Although this variant has been considered clinically benign, it can lead to significant clinical issues, such as arrhythmia, myocardial ischemia, conduction disturbances, myocardial infarction and sudden death in a subset of patients. Autopsy and computed tomography studies have identified MB in –25% of patients, whereas only 10% of patients have angiographically detectable systolic compression. Intravascular imaging is more sensitive than angiography for detecting minor MB compression.
In general, symptomatic patients should be treated conservatively with medical management consisting of beta-blockers and non-dihydropyridine calcium-channel blockers to reduce arterial compression by the muscular band and slow the heart rate, thereby increasing the diastolic period. Various strategies, including surgery have been attempted to treat refractory symptoms, depending on the patient’s status.

View full abstract

Although the multi-arterial grafting strategy is widely accepted in Japan, saphenous vein grafts (SVGs) are still commonly used worldwide. SVGs have a high failure rate of 8–25% at 1 year, with only 50–60% remaining patent after a decade. Pathological changes, such as intimal hyperplasia and atherosclerosis have been well studied, and graft distention, size mismatch and deprivation of perivascular adipose tissue are risk factors related to long-term SVG graft patency. The new no-touch harvesting technique has demonstrated improved long-term graft patency rates. This review summarizes the relevant literature detailing no-touch SVG harvesting in coronary artery bypass grafting.

View full abstract

Objective: We examined the accuracy of coronary calcification volume (CV) measurements using deep-learning artificial intelligence (AI) for non-electrocardiogram (ECG)-gated chest computed tomography (CT) and compared it with the accuracy of the CV measured with a commercially available workstation (WS) and the Agatston score (AS). We showed the potential, limitations, and optimization of AI for evaluating coronary artery disorders.
Materials and methods: Overall, 315 of 344 patients were analyzed. All patients underwent non-ECG-gated and ECG-gated non-enhanced CT during preoperative chest screening and/or chest pain assessment from March 7, 2021, to March 7, 2022. The accuracy of CV-AI was compared with that of CV-WS and the AS. Stratification grades based on CV-AI were compared with grades based on the AS. Cases of mismatched stratification were examined to determine the limitations of AI. The cut-off value with the best stratification of CV-AI was obtained.
Results: The correlation coefficients between CV-AI and CV-WS and the AS were 0.964 (p < 0.01) and 0.960 (p < 0.01), respectively. Stratification of coronary risks showed significant consistency between methods (p < 0.01), and categories were matched in 81.0% of cases. When the AS was regarded as the “gold standard”, the accuracy, sensitivity, specificity, negative and positive predictive values, and Dice and Jaccard indices were 0.946, 0.921, 1, 0.856, 1, 0.959, and 0.921, respectively. AI rarely overlooked calcifications to underestimate coronary risks. The best cut-off values for categorization were 10-100-360 (default: 10-100-500).
Conclusion: AI has sufficient potential to stratify the risk of coronary events on non-ECG-gated chest CT, particularly for non-cardiac patients. However, the results of AI analyses should not be blindly accepted.

View full abstract

Papillary muscle rupture may occur even in patients with small or no myocardial ischemic lesion, and it may also arise from iatrogenic complications. We report a case of papillary muscle rupture following artery dissection, that apparently occurred due to catheter intervention. An 83-year-old woman with stable angina pectoris underwent percutaneous coronary intervention. Coronary artery dissection occurred during the procedure; however, she showed no ischemic symptoms or change in her laboratory parameters. She presented with dyspnea after 9 days. Echocardiography showed massive mitral regurgitation and a ruptured posterior median papillary muscle. She underwent emergent mitral valve replacement and recovered without complications. Papillary muscle rupture following coronary artery dissection associated with catheter intervention is an extremely rare but serious complication, and even a small ischemic area merits observation.

View full abstract