A Complex Case of Pregnancy-related Left Main Stem Spontaneous Coronary Artery Dissection

Spontaneous coronary artery dissection (SCAD) is a less common cause of acute coronary syndrome. Pregnancy-related SCAD is uncommon, but often presents with a more severe phenotype. This report describes a 30-year-old woman with an anterior ST elevation MI, presenting 1 day postpartum. Left main stem (LMS) SCAD with extensive intramural haematoma (IMH) and resultant LMS occlusion was confirmed by angiography and intravascular imaging. Given the extent of disease, the patient underwent emergency cardiac surgery. Coronary flow was initially improved by decompressing the IMH using cutting balloons. The coronary wires were successfully left in situ during transfer in an effort to both maintain flow and allow the surgeon to identify true LMS. Ideally, SCAD can be managed conservatively given the risk of intervention worsening IMH, and hence myocardial ischaemia/MI. However, emergency revascularisation is indicated in cases of persistent ischaemia. This case demonstrates percutaneous therapies to bridge towards and help with subsequent surgical revascularisation

Assessment of hemodynamic indices of conjunctival microvascular function in patients with coronary microvascular dysfunction

Objective: Coronary microvascular dysfunction (CMD) is a cause of ischaemia with non-obstructive coronary arteries (INOCA). It is notoriously underdiagnosed due to the need for invasive microvascular function testing. We hypothesized that systemic microvascular dysfunction could be demonstrated non-invasively in the microcirculation of the bulbar conjunctiva in patients with CMD. Methods: Patients undergoing coronary angiography for the investigation of chest pain or dyspnoea, with physiologically insignificant epicardial disease (fractional flow reserve ≥0.80) were recruited. All patients underwent invasive coronary microvascular function testing. We compared a cohort of patients with evidence of CMD (IMR ≥25 or CFR &lt;2.0); to a group of controls (IMR &lt;25 and CFR ≥2.0). Conjunctival imaging was performed using a previously validated combination of a smartphone and slit-lamp biomicroscope. This technique allows measurement of vessel diameter and other indices of microvascular function by tracking erythrocyte motion. Results: A total of 111 patients were included (43 CMD and 68 controls). There were no differences in baseline demographics, co-morbidities or epicardial coronary disease severity. The mean number of vessel segments analysed per patient was 21.0 ± 12.8 (3.2 ± 3.5 arterioles and 14.8 ± 10.8 venules). In the CMD cohort, significant reductions were observed in axial/cross-sectional velocity, blood flow, wall shear rate and stress. Conclusion: The changes in microvascular function linked to CMD can be observed non-invasively in the bulbar conjunctiva. Conjunctival vascular imaging may have utility as a non-invasive tool to both diagnose CMD and augment conventional cardiovascular risk assessment.</p

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

Assessment of indices of conjunctival microvascular function in patients with and without obstructive coronary artery disease

Background: Atherosclerotic heart disease often remains asymptomatic until presentation with a major adverse cardiovascular event. Primary preventive therapies improve outcomes, but conventional screening often misattributes risk. Vascular imaging can be utilised to detect atherosclerosis, but often involves ionising radiation. The conjunctiva is a readily accessible vascular network allowing non-invasive hemodynamic evaluation. Aim: To compare conjunctival microcirculatory function in patients with and without obstructive coronary artery disease. Methods: We compared the conjunctival microcirculation of myocardial infarction patients (MI-cohort) to controls with no obstructive coronary artery disease (NO-CAD cohort). Conjunctival imaging was performed using a smartphone and slit-lamp biomicroscope combination. Microvascular indices of axial (V a) and cross-sectional (V cs) velocity; blood flow rate (Q); and wall shear rate (WSR) were compared in all conjunctival vessels between 5 and 45 μm in diameter. Results: A total of 127 patients were recruited (66 MI vs 61 NO-CAD) and 3602 conjunctival vessels analysed (2414 MI vs 1188 NO-CAD). Mean V a, V cs and Q were significantly lower in the MI vs NO-CAD cohort (V a 0.50 ± 0.17 mm/s vs 0.55 ± 0.15 mm/s, p &lt; 0.001; V cs 0.35 ± 0.12 mm/s vs 0.38 ± 0.10 mm/s, p &lt; 0.001; Q 154 ± 116 pl/s vs 198 ± 130 pl/s, p &lt; 0.001). To correct for differences in mean vessel diameter, WSR was compared in 10–36 μm vessels (3268/3602 vessels) and was lower in the MI-cohort (134 ± 64 s −1 vs 140 ± 63 s −1, p = 0.002). Conclusions: Conjunctival microcirculatory alterations can be observed in patients with obstructive coronary artery disease. The conjunctival microvasculature merits further evaluation in cardiovascular risk screening.</p