Background: optical coherence tomography (OCT) might allow identifying lesion features reportedly associated with plaque vulnerability and increased risk of clinical events. Previous studies on correlation between OCT and functional lesion significance indices reported contradictory results, yet integration of complementary information from both modalities is gaining increased interest. The aim of the study was to compare plaque morphology using OCT in hemodynamically relevant vs. non-relevant lesions by fractional flow reserve (FFR). Methods: consecutive patients with intermediate grade coronary stenoses by angiography were evaluated by both FFR and OCT in this single-center study. Stenoses were labeled hemodynamically relevant in case of the FFR ≤ 0.80. Minimal lumen area (MLA), fibrous cap thickness (FCT), minimal cap thickness over the calcium, angle of the calcium, and necrotic core within the lesions were evaluated. Results: a total of 105 patients (124 vessels) were analyzed. Of them, 65 patients were identified with at least one lesion identified as hemodynamically relevant by FFR (72 vessels, 58.1%). Lesions with FFR ≤0.80 presented with lower mean and minimal lumen area (3.46 ± 1.29 vs. 4.65 ± 2.19, p =0.001 and 1.84 ± 0.97 vs. 2.66 ± 1.40, p = 0.001) compared to patients with FFR > 0.80. No differences were found between groups in the mean and minimal FCT, mean, and maximal necrotic core, calcium angle, as well as the overall rate of calcified and lipid plaques. Conclusion: hemodynamic relevance of intermediate grade lesions correlated moderately with the luminal assessment by OCT. No differences were identified in the plaque morphology between relevant and non-relevant coronary stenoses by FFR.

Takotsubo syndrome (TTS) consists of transient dysfunction of the left and/or right ventricle in the absence of ruptured plaque; thrombus or vessel dissection. TTS may be divided into two categories. Primary TTS occurs when the cause of hospitalization is the symptoms resulting from damage to the myocardium usually preceded by emotional stress. Secondary TTS occurs in patients hospitalized for other medical; surgical; anesthetic; obstetric or psychiatric conditions who have activation of their sympathetic nervous system and catecholamines release- they develop TTS as a complication of their primary condition or its treatment. There are several hypotheses concerning the cause of the disease. They include a decrease in estrogen levels; microcirculation dysfunction; endothelial dysfunction and the hypothesis based on the importance of the brain-heart axis. More and more research concerns the importance of genetic factors in the development of the disease. To date; no effective treatment or prevention of recurrent TTS has been found. Only when the pathophysiology of the disease is fully known; then personalized treatment will be possible.

Today, coronary artery disease (CAD) continues to be a prominent cause of death worldwide. A reliable assessment of coronary stenosis represents a prerequisite for the appropriate management of CAD. Nevertheless, there are still major challenges pertaining to some limitations of current imaging and functional diagnostic modalities. The present review summarizes the current data on invasive functional and intracoronary imaging assessment using optical coherence tomography (OCT), and intravascular ultrasound (IVUS). Amongst the functional parameters—on top of fractional flow reserve (FFR) and instantaneous wave-free ratio (iFR)—we point to novel angiography-based measures such as quantitative flow ratio (QFR), vessel fractional flow reserve (vFFR), angiography-derived fractional flow reserve (FFRangio), and computed tomography-derived flow fractional reserve (FFR-CT), as well as hybrid approaches focusing on optical flow ratio (OFR), computational fluid dynamics and attempts to quantify the forces exaggerated by blood on the coronary plaque and vessel wall.