The haemodynamic effects of collateral donation to a chronic total occlusion : implications for patient management

Physiological lesion assessment in the form of Fractional Flow Reserve (FFR) is now well established for the purpose of guiding multi-vessel revascularization. Chronic total coronary occlusions are frequently associated with multi-vessel disease and the collateral dependent myocardium distal to the occlusion is often supplied by a collateral supply from another epicardial coronary artery. The haemodynamic effect of collateral donation upon collateral donor vessel flow may have important implications for the vessel's FFR; rendering it unreliable at predicting ischaemia should the CTO be revascularized. As a consequence, in the setting of multi-vessel disease, optimal revascularization strategy might be altered. There is a paucity of work in the medical literature directly examining this phenomenon. We endeavoured to review the existing literature related to it, to summarise from current knowledge of coronary physiology what is known about the potential effects of CTO revascularization on both collateral flow and collateral donor vessel physiology, and to highlight where further studies might inform practice

Systematic review and meta-analysis of optimal P2Y₁₂ blockade in dual antiplatelet therapy for patients with diabetes with acute coronary syndrome

Background: Patients with diabetes are at increased risk of acute coronary syndromes (ACS) and their mortality and morbidity outcomes are significantly worse following ACS events, independent of other comorbidities. This systematic review sought to establish the optimum management strategy with focus on P2Y₁₂ blockade in patients with diabetes with ACS. Methods: MEDLINE (1946 to present) and EMBASE (1974 to present) databases, abstracts from major cardiology conferences and previously published systematic reviews were searched to June 2014. Relevant randomised control trials with clinical outcomes for P2Y₁₂ inhibitors in adult patients with diabetes with ACS were scrutinised independently by 2 authors with applicable data was extracted for primary composite end point of cardiovascular death, myocardial infarction (MI) and stroke; enabling calculation of relative risks with 95% CI with subsequent direct and indirect comparison. Results: Four studies studied clopidogrel in patients with diabetes, with two (3122 patients) having primary outcome data showing superiority of clopidogrel against placebo with RR0.84 (95% CI 0.72–0.99). Irrespective of management strategy, the newer agents prasugrel (2 studies) and ticagrelor (1 study) had a lower primary event rate compared with clopidogrel; RR 0.80 (95% CI 0.66 to 0.97) and RR 0.89 (95% CI 0.77 to 1.02), respectively. When ticagrelor was indirectly compared with prasugrel, there was a trend to an improved primary outcome with prasugrel (RR 1.11 (95% CI 0.94 to 1.31)) particularly in those managed with percutaneous coronary intervention (PCI) (RR 1.23 (95% CI 0.95 to 1.59)). Prasugrel demonstrated a statistical superiority with prevention of further MI with RR 1.48 (95% CI 1.11 to 1.97). This was not at the expense of increased major thrombolysis in MI (TIMI) bleeding rates RR 0.94 (95% CI 0.59 to 1.51). Conclusions: This meta-analysis shows the addition of a P2Y₁₂ inhibitor is superior to placebo, with a trend favouring the use of prasugrel in patients with diabetes with ACS, particularly those undergoing PCI

Medical therapy, percutaneous coronary intervention and prognosis in patients with chronic total occlusions

Objective There is little published data reporting outcomes for those found to have a chronic total coronary occlusion (CTO) that is electively treated medically versus those treated by percutaneous coronary intervention (PCI). We sought to compare long-term clinical outcomes between patients treated by PCI and elective medical therapy in a consecutive cohort of patients with an identified CTO. Methods Patients found to have a CTO on angiography between January 2002 and December 2007 in a single tertiary centre were identified using a dedicated database. Those undergoing CTO PCI and elective medical therapy to the CTO were propensity matched to adjust for baseline clinical and angiographic differences. Results In total, 1957 patients were identified, a CTO was treated by PCI in 405 (20.7%) and medical therapy in 667 (34.1%), 885 (45.2%) patients underwent coronary artery bypass graft surgery. Of those treated by PCI or medical therapy, propensity score matching identified 294 pairs of patients, PCI was successful in 177 patients (60.2%). All-cause mortality at 5 years was 11.6% for CTO PCI and 16.7% for medical therapy HR 0.63 (0.40 to 1.00, p=0.052). The composite of 5-year death or myocardial infarction occurred in 13.9% of the CTO PCI group and 19.6% in the medical therapy group, HR 0.64 (0.42 to 0.99, p=0.043). Among the CTO PCI group, if the CTO was revascularised by any means during the study period, 5-year mortality was 10.6% compared with 18.3% in those not revascularised in the medical therapy group, HR 0.50 (0.28–0.88, p=0.016). Conclusions Revascularisation, but not necessarily PCI of a CTO, is associated with improved long-term survival relative to medical therapy alone

Microvascular dysfunction in the immediate aftermath of chronic total coronary occlusion recanalization

Objectives The aim of this study was to compare microvascular resistance under both baseline and hyperemic conditions immediately after percutaneous coronary intervention (PCI) of a chronic total occlusion (CTO) with an unobstructed reference vessel in the same patient. Background Microvascular dysfunction has been reported to be prevalent immediately after CTO PCI. However, previous studies have not made comparison with a reference vessel. Patients with a CTO may have global microvascular and/or endothelial dysfunction, making comparison with established normal values misleading. Methods After successful CTO PCI in 21 consecutive patients, coronary pressure and flow velocity were measured at baseline and hyperemia in distal segments of the CTO/target vessel and an unobstructed reference vessel. Hemodynamics including hyperemic microvascular resistance (HMR), basal microvascular resistance (BMR), and instantaneous minimal microvascular resistance at baseline and hyperemia were calculated and compared between reference and target/CTO vessels. Results After CTO PCI, BMR was reduced in the target/CTO vessel compared with the reference vessel: 3.58 mm Hg/cm/s vs 4.94 mm Hg/cm/s, difference −1.36 mm Hg/cm/s (−2.33 to −0.39, p = 0.008). We did not detect a difference in HMR: 1.82 mm Hg/cm/s vs 2.01 mm Hg/cm/s, difference −0.20 (−0.78 to 0.39, p = 0.49). Instantaneous minimal microvascular resistance correlated strongly with the length of stented segment at baseline (r = 0.63, p = 0.005) and hyperemia (r = 0.68, p = 0.002). Conclusions BMR is reduced in a recanalized CTO in the immediate aftermath of PCI compared to an unobstructed reference vessel; however, HMR appears to be preserved. A longer stented segment is associated with increased microvascular resistance

Contemporary Percutaneous Coronary Intervention for Complex Lesions: the Treatment of Chronic Total Occlusions and Bifurcations in the Drug-eluting Stent Era

When used in relatively simple lesions, randomized studies have demonstrated efficacy of drug-eluting stents in significantly reducing restenosis compared with bare metal stents. However, lesions such as chronic total occlusions and bifurcations which are at increased risk of restenosis were excluded. In this thesis, contemporary percutaneous coronary intervention of these lesion subsets are evaluated, including assessment of the efficacy of sirolimus- and paclitaxel-eluting stent implantation

Biomarkers of coronary endothelial health: correlation with invasive measures of collateral function, flow and resistance in chronically occluded coronary arteries and the effect of recanalization

Objectives: In the presence of a chronically occluded coronary artery, the collateral circulation matures by a process of arteriogenesis; however, there is considerable variation between individuals in the functional capacity of that collateral network. This could be explained by differences in endothelial health and function. We aimed to examine the relationship between the functional extent of collateralization and levels of biomarkers that have been shown to relate to endothelial health. Methods: We measured four potential biomarkers of endothelial health in 34 patients with mature collateral networks who underwent a successful percutaneous coronary intervention (PCI) for a chronic total coronary occlusion (CTO) before PCI and 6-8 weeks after PCI, and examined the relationship of biomarker levels with physiological measures of collateralization. Results: We did not find a significant change in the systemic levels of sICAM-1, sE-selectin, microparticles or tissue factor 6-8 weeks after PCI. We did find an association between estimated retrograde collateral flow before CTO recanalization and lower levels of sICAM-1 (r=0.39, P=0.026), sE-selectin (r=0.48, P=0.005) and microparticles (r=0.38, P=0.03). Conclusion: Recanalization of a CTO and resultant regression of a mature collateral circulation do not alter systemic levels of sICAM-1, sE-selectin, microparticles or tissue factor. The identified relationship of retrograde collateral flow with sICAM-1, sE-selectin and microparticles is likely to represent an association with an ability to develop collaterals rather than their presence and extent

The HF-CGM study: An analysis of cardiogoniometric axes in patients with cardiac resynchronization therapy

Goal: The HF-CGM is a proof-of-principle study to investigate whether cardiogoniometry (CGM), a three-dimensional electrocardiographic method, can differentiate between pacing modes in patients with cardiac resynchronization therapy (CRT). Methods: At a tertiary cardiology center, CGM recordings were performed using four pacing modes: no pacing; right ventricular (RV) pacing; left ventricular (LV) pacing, and biventricular (BIV) pacing. Three orthogonal CGM planes orientated to the long axis (XY), the frontal plane (YZ), and the short axis (XZ) of the heart were constructed, and the direction of the QRS-axis was calculated for each pacing mode in each plane. During BIV pacing, the direction of CGM QRS-axis was compared between patients with optimal and nonoptimal 12-lead pacing variables. Results: Twenty-two participants (aged 71.5 ± 10.8; 77.3% male, LVEF 29 ± 7%) were consecutively recruited. Only QRS-axis measured in the XY plane could significantly distinguish between all three pacing modes versus no pacing. Mean QRS-axis in the XY plane with pacing off and during RV pacing was leftward and basal; LV pacing was apical; and BIV pacing was rightward and basal. There was a statistically significant difference in the direction of the QRS-axis between patients with optimal versus nonoptimal paced QRS morphology in the XY plane (rightward and basal versus inconsistent). Significance : CGM recorded in the XY plane can accurately detect differences between ventricular pacing sites. It may also be able to identify patients with a CRT device in situ who have optimal response

Outcomes After Percutaneous Coronary Intervention in Women: Are There Differences When Compared with Men?

Despite advances in the diagnosis and treatment of coronary artery disease, there remains evidence of a disparity in the outcomes for women when compared with men. This article provides a review of the evidence for this discrepancy and discusses some of the potential contributing factors

Influence of case definition on incidence and outcome of acute coronary syndromes

© 2016, BMJ Publishing Group. All rights reserved. Objective: Acute coronary syndromes (ACS) are common, but their incidence and outcome might depend greatly on how data are collected. We compared case ascertainment rates for ACS and myocardial infarction (MI) in a single institution using several different strategies. Methods: The Hull and East Yorkshire Hospitals serve a population of ∼560 000. Patients admitted with ACS to cardiology or general medical wards were identified prospectively by trained nurses during 2005. Patients with a death or discharge code of MI were also identified by the hospital information department and, independently, from Myocardial Infarction National Audit Project (MINAP) records. The hospital laboratory identified all patients with an elevated serum troponin-T (TnT) by contemporary criteria ( > 0.03 μg/L in 2005). Results: The prospective survey identified 1731 admissions (1439 patients) with ACS, including 764 admissions (704 patients) with MIs. The hospital information department reported only 552 admissions (544 patients) with MI and only 206 admissions (203 patients) were reported to the MINAP. Using all 3 strategies, 934 admissions (873 patients) for MI were identified, for which TnT was > 1 μg/L in 443, 0.04-1.0 μg/L in 435, =0.03 μg/L in 19 and not recorded in 37. A further 823 patients had TnT > 0.03 μg/L, but did not have ACS ascertained by any survey method. Of the 873 patients with MI, 146 (16.7%) died during admission and 218 (25.0%) by 1 year, but ranging from 9% for patients enrolled in the MINAP to 27% for those identified by the hospital information department. Conclusions: MINAP and hospital statistics grossly underestimated the incidence of MI managed by our hospital. The 1-year mortality was highly dependent on the method of ascertainment