Coronary microcirculation in acute myocardial ischaemia: From non-invasive to invasive absolute flow assessment.

Although substantial progress has been made in recent decades in reducing mortality and performing optimal revascularization in patients with myocardial infarction, ischaemic heart disease, including acute coronary syndrome, remains the leading cause of mortality worldwide. One of the remaining challenges is to better detect, prevent and treat extended myocardial damage despite angiographically optimal revascularization. Several indices are available in clinical practice to evaluate myocardial damage, infarct size and potential myocardial recovery. These indices are divided into two categories: non-invasive, generally performed after revascularization; and invasive, performed during the revascularization procedure. They allow the clinician to detect patients at risk and may help us to tailor the medical therapy and discharge strategy according to myocardial damage. Because of the number of indices, it is difficult to properly evaluate new therapeutics or to adopt one index that will provide sufficient data to better evaluate and understand the part of the coronary vasculature that is not seen - the microcirculation or so-called "black box". The aim of this review is to describe the non-invasive and invasive indices used to describe the microcirculation and their ability to predict clinical impact, and current dedicated therapeutics that may help to reduce microvascular damage and improve clinical outcomes.

Comparison of 2-Dimensional, 3-Dimensional, and Surgical Measurements of the Tricuspid Annulus Size: Clinical Implications.

BACKGROUND: Associated tricuspid annuloplasty is recommended during left-heart valve surgery when the tricuspid annulus (TA) is dilated but methodology for the measurement of TA size and thresholds for TA enlargement are not clearly defined. METHODS AND RESULTS: Measurement of the TA diameter (TAD) was prospectively performed using 2-dimensional transthoracic echocardiography (2D-TTE) in 282 patients in 4 different views (parasternal long axis, parasternal short axis, apical 4-chamber [A4C], and subcostal). TAD was also measured using 3D-transesophageal echocardiography in 183 patients (long axis), peroperatively in 120 patients who underwent a tricuspid valve surgery and using TTE (A4C) in 66 healthy volunteers. TAD was significantly different between the 4 2D-TTE views (3.85±0.58, 3.87±0.61, 4.02±0.69, and 3.92±0.65 cm, respectively; P<0.0001) but differences were small and the A4C was the most feasible (76%, 65%, 92%, and 73%, respectively; P<0.0001) and offered the highest reproducibility. TAD measured in A4C view was smaller than when measured by 3D-transesophageal echocardiography (3.90±0.63 versus 4.33±0.62 cm; P<0.0001) but correlation was excellent (r=0.84; P<0.0001) with a systematic 4-mm underestimation. In contrast, 2D-TTE measurements were significantly smaller and only modestly correlated to surgical measurements (4.11±0.61 versus 4.37±0.75 cm; P<0.0001; r=0.57; P<0.0001) which were poorly reproducible. In healthy volunteers, we suggested 42 mm or 23 mm/m(2) as pathological values for the TAD in A4C. CONCLUSIONS: Measurements of the TAD using 2D-TTE in A4C were highly feasible and reproducible and despite being systematically smaller than 3D measurements, accurately reflected the degree of TA enlargement as assessed using 3D transesophageal echocardiography. We proposed the thresholds that may be used in future prospective studies to demonstrate whether a preventive strategy would improve the outcome.