Placebo Control and Blinding in Randomized Trials of Procedural Interventions: A Systematic Review and Meta-Regression.

Importance: Unlike medications, procedural interventions are rarely trialed against placebo prior to becoming accepted in clinical practice. When placebo-controlled trials are eventually conducted, procedural interventions may be less effective than previously believed. Objective: To investigate the importance of including a placebo arm in trials of surgical and interventional procedures by comparing effect sizes from trials of the same procedure that do and do not include a placebo arm. Data Sources: Searches of MEDLINE and Embase identified all placebo-controlled trials for procedural interventions in any specialty of medicine and surgery from inception to March 31, 2019. A secondary search identified randomized clinical trials assessing the same intervention, condition, and end point but without a placebo arm for paired comparison. Study Selection: Placebo-controlled trials of anatomically site-specific procedures requiring skin incision or endoscopic techniques were eligible for inclusion; these were then matched to trials without placebo control that fell within prespecified limits of heterogeneity. Data Extraction and Synthesis: Random-effects meta-regression, with placebo and blinding as a fixed effect and intervention and end point grouping as random effects, was used to calculate the impact of placebo control for each end point. Data were analyzed from March 2019 to March 2020. Main Outcomes and Measures: End points were examined in prespecified subgroups: patient-reported or health care professional-assessed outcomes, quality of life, pain, blood pressure, exercise-related outcomes, recurrent bleeding, and all-cause mortality. Results: Ninety-seven end points were matched from 72 blinded, placebo-controlled trials (hereafter, blinded) and 55 unblinded trials without placebo control (hereafter, unblinded), including 111 500 individual patient end points. Unblinded trials had larger standardized effect sizes than blinded trials for exercise-related outcomes (standardized mean difference [SMD], 0.59; 95% CI, 0.29 to 0.89; P < .001) and quality-of-life (SMD, 0.32; 95% CI, 0.11 to 0.53; P = .003) and health care professional-assessed end points (SMD, 0.40; 95% CI, 0.18 to 0.61; P < .001). The placebo effect accounted for 88.1%, 55.2%, and 61.3% of the observed unblinded effect size for these end points, respectively. There was no significant difference between unblinded and blinded trials for patient-reported end points (SMD, 0.31; 95% CI, -0.02 to 0.64; P = .07), blood pressure (SMD, 0.26; 95% CI, -0.10 to 0.62; P = .15), all-cause mortality (odds ratio [OR], 0.23; 95% CI, -0.26 to 0.72; P = .36), pain (SMD, 0.03; 95% CI, -0.52 to 0.57; P = .91), or recurrent bleeding events (OR, -0.12; 95% CI, -1.11 to 0.88; P = .88). Conclusions and Relevance: The magnitude of the placebo effect found in this systematic review and meta-regression was dependent on the end point. Placebo control in trials of procedural interventions had the greatest impact on exercise-related, quality-of-life, and health care professional-assessed end points. Randomized clinical trials of procedural interventions may consider placebo control accordingly.

The ability of contemporary cardiologists to judge the ischemic impact of a coronary lesion visually

BACKGROUND: Landmark trials showed that invasive pressure measurement (Fractional Flow Reserve, FFR) was a better guide to coronary stenting than visual assessment. However, present-day interventionists have benefited from extensive research and personal experience of mapping anatomy to hemodynamics. AIMS: To determine if visual assessment of the angiogram performs as well as invasive measurement of coronary physiology. METHODS: 25 interventional cardiologists independently visually assessed the single vessel coronary disease of 200 randomized participants in The Objective Randomized Blinded Investigation with optimal medical Therapy of Angioplasty in stable angina trial (ORBITA). They gave a visual prediction of the FFR and Instantaneous Wave-free Ratio (iFR), denoted vFFR and viFR respectively. Each judged each lesion on 2 occasions, so that every lesion had 50 vFFR, and 50 viFR assessments. The group consensus visual estimates (vFFR-group and viFR-group) and individual cardiologists' visual estimates (vFFR-individual and viFR-individual) were tested alongside invasively measured FFR and iFR for their ability to predict the placebo-controlled reduction in stress echo ischemia with stenting. RESULTS: Placebo-controlled ischemia improvement with stenting was predicted by vFFR-group (p < 0.0001) and viFR-group (p < 0.0001), vFFR-individual (p < 0.0001) and viFR-individual (p < 0.0001). There were no significant differences between the predictive performance of the group visual estimates and their invasive counterparts: p = 0.53 for vFFR vs FFR and p = 0.56 for viFR vs iFR. CONCLUSION: Visual assessment of the angiogram by contemporary experts, provides significant additional information on the amount of ischaemia which can be relieved by placebo-controlled stenting in single vessel coronary artery disease.

The ability of contemporary cardiologists to judge the ischemic impact of a coronary lesion visually.

BACKGROUND: Landmark trials showed that invasive pressure measurement (Fractional Flow Reserve, FFR) was a better guide to coronary stenting than visual assessment. However, present-day interventionists have benefited from extensive research and personal experience of mapping anatomy to hemodynamics. AIMS: To determine if visual assessment of the angiogram performs as well as invasive measurement of coronary physiology. METHODS: 25 interventional cardiologists independently visually assessed the single vessel coronary disease of 200 randomized participants in The Objective Randomized Blinded Investigation with optimal medical Therapy of Angioplasty in stable angina trial (ORBITA). They gave a visual prediction of the FFR and Instantaneous Wave-free Ratio (iFR), denoted vFFR and viFR respectively. Each judged each lesion on 2 occasions, so that every lesion had 50 vFFR, and 50 viFR assessments. The group consensus visual estimates (vFFR-group and viFR-group) and individual cardiologists' visual estimates (vFFR-individual and viFR-individual) were tested alongside invasively measured FFR and iFR for their ability to predict the placebo-controlled reduction in stress echo ischemia with stenting. RESULTS: Placebo-controlled ischemia improvement with stenting was predicted by vFFR-group (p < 0.0001) and viFR-group (p < 0.0001), vFFR-individual (p < 0.0001) and viFR-individual (p < 0.0001). There were no significant differences between the predictive performance of the group visual estimates and their invasive counterparts: p = 0.53 for vFFR vs FFR and p = 0.56 for viFR vs iFR. CONCLUSION: Visual assessment of the angiogram by contemporary experts, provides significant additional information on the amount of ischaemia which can be relieved by placebo-controlled stenting in single vessel coronary artery disease.

Vessel-Specific Outcomes of Deferred Revascularization Following Negative Fractional Flow Reserve.

Variations in myocardial supply area and hydrostatic pressure gradients result in greater likelihood of positive fractional flow reserve (FFR) in the left anterior descending (LAD) compared with the circumflex (Cx) and right coronary artery (RCA). However, the same FFR threshold for deferral of revascularization is applied to all arteries, without evidence that this results in equivalent outcomes. We assessed vessel-specific outcomes of deferred revascularization for the 3 major coronary arteries based on FFR > 0.8. In this retrospective study, data were obtained on consecutive patients who underwent indicated FFR assessment across 2 tertiary institutions. Patients with deferred revascularization were followed for 36 months for the primary end point of vessel-specific target lesion failure (TLF). Of 1,916 major coronary arteries (1,579 patients), the odds ratio of positive FFR was highest in the LAD (odds ratio 3.36, p <0.001). In total, 867 vessels (733 patients) with FFR > 0.8 had complete 3-year medical record follow-ups. The TLF rate for deferred vessels was 10.21%, 11.52%, and 10.96% for the LAD, Cx, and RCA respectively. In a multivariate analysis, there was no significant difference in the odds of TLF for the 0.84 (0.53 to 1.33, p = 0.459), 1.17 (0.68 to 2.01, p = 0.582), and 1.11 (0.62 to 2.00, p = 0.715) in the LAD, Cx, and RCA, respectively. In a multivariate analysis, diabetes mellitus was the only baseline characteristic significantly associated at risk of TLF (1.43 [1.01 to 2.02], p = 0.043). In conclusion, despite greater likelihood of positive FFR in the LAD, the FFR threshold for deferred revascularization resulted in equivalent outcomes in all 3 major coronary arteries, and patients with diabetes mellitus may represent a group that requires aggressive surveillance and risk factor modification after deferred revascularization.

Angiographic predictors of coronary hemodynamics.

Aims: Assess the correlation between diameter stenosis, lesion length, location, diffuse coronary disease and with fractional flow reserve (FFR). Methods/Results: We performed quantitative coronary analysis analysis on 384 lesions with stable coronary artery disease undergoing FFR assessment. Vessels were 59.1% left anterior descending artery (LAD), 16.1% left circumflex artery and 14.8% right coronary artery. Median diameter stenosis was 58% ± 2.5 and median lesion length was 10 mm ± 7.36. 21% of vessels were diffusely diseased. Lesions were 33.6% proximal, 44% mid-vessel and 12% distal. Median FFR was 0.85. Diameter stenosis correlated with lower FFR (p < 0.005, odds ratio [OR]: 2.4 [95% CI: 0.99-5.63]). There was no association between lesion length, location, number of proximal side branches and FFR. Vessels with diffuse disease had a nonsignificant trend for lower FFR (0.84 vs 0.85, p = 0.375, OR: 1.26 [95% CI: 0.76-2.09]). LAD lesions had significantly lower FFR compared with non-LAD (p < 0.001, OR: 2.55 [95% CI: 1.61-4.04]); including left circumflex artery and right coronary artery lesions (p = 0.001, OR: 3.4 [95% CI: 1.7-6.9]) and p = 0.02, OR: 2.55 [95% CI: 1.17-4.34]). Conclusion: FFR is not related to lesion length, location or number of proximal branches.

The Woven EndoBridge Device for the Treatment of Intracranial Aneurysms: Initial Clinical Experience within an Australian Population.

PURPOSE: Advances in endovascular technology have expanded the treatment options for intracranial aneurysms. Intrasaccular flow diversion is a relatively new technique that aims to disrupt blood inflow at the neck of the aneurysm, hence promoting intrasaccular thrombosis. The Woven EndoBridge device (WEB; MicroVention, Aliso Viejo, CA, USA) is an US Food and Drug Administration approved intrasaccular flow diverter for wide-necked aneurysms. We report the early interim clinical and radiological outcomes of patients with both ruptured and unruptured intracranial aneurysms (IAs) treated using the WEB device in an Australian population. MATERIALS AND METHODS: A retrospective analysis was done of patients with ruptured or unruptured IAs who received treatment with WEB across 5 Australian neuroendovascular referral centers between May 2017 and November 2020. Angiographic occlusion was assessed with time-of-flight magnetic resonance angiography. Complications were recorded and clinical outcomes were assessed using the modified Rankin scale at follow-up. RESULTS: In total, 66 aneurysms were treated in 63 patients, with successful deployment of the WEB device in 98.5% (n=65). Eighteen (26.9%) ruptured aneurysms were included. Failure of deployment occurred in a single case. Adjunct coiling and/or stenting was performed in 20.9% (n=14) cases. Sixty-two patients with 65 aneurysms using a WEB device were followed up (mean=9.1 months), and 89.4% of these had complete aneurysm occlusion while 1.5% remained patent. Functional independence was achieved in 93.5% of cases. CONCLUSION: Early results following the use of WEB devices in Australia demonstrate safety and adequate aneurysm occlusion comparable to international literature.

Cardiovascular Disease in Australians Experiencing Homelessness.

Australia has one of the highest rates of homelessness in the world, at 498 per 100,000 people, and Australians experiencing homelessness (AEH) are a particularly vulnerable cohort, with a greater prevalence of cardiovascular disease, and poorer health outcomes, when compared to the general population. This narrative review explores how a combination of inadequately managed traditional and non-traditional cardiovascular risk factors, along with several personal, practical and relationship challenges with the health system, have created unique barriers in the diagnosis and management of cardiovascular disease in AEH. To help address these inequalities, we propose a targeted and collaborative strategy, which includes government proactivity, stable and affordable housing, and involvement of specialist health professionals, community leaders and major homelessness organisations. Furthermore, the delivery of health care needs to be a combination of outreach and opportunistic services, with a focus on flexible and individualised preventative care.

Association of hypertension with mortality in patients hospitalised with COVID-19.

OBJECTIVE: To assess whether hypertension is an independent risk factor for mortality among patients hospitalised with COVID-19, and to evaluate the impact of ACE inhibitor and angiotensin receptor blocker (ARB) use on mortality in patients with a background of hypertension. METHOD: This observational cohort study included all index hospitalisations with laboratory-proven COVID-19 aged ≥18 years across 21 Australian hospitals. Patients with suspected, but not laboratory-proven COVID-19, were excluded. Registry data were analysed for in-hospital mortality in patients with comorbidities including hypertension, and baseline treatment with ACE inhibitors or ARBs. RESULTS: 546 consecutive patients (62.9±19.8 years old, 51.8% male) hospitalised with COVID-19 were enrolled. In the multivariable model, significant predictors of mortality were age (adjusted OR (aOR) 1.09, 95% CI 1.07 to 1.12, p<0.001), heart failure or cardiomyopathy (aOR 2.71, 95% CI 1.13 to 6.53, p=0.026), chronic kidney disease (aOR 2.33, 95% CI 1.02 to 5.32, p=0.044) and chronic obstructive pulmonary disease (aOR 2.27, 95% CI 1.06 to 4.85, p=0.035). Hypertension was the most prevalent comorbidity (49.5%) but was not independently associated with increased mortality (aOR 0.92, 95% CI 0.48 to 1.77, p=0.81). Among patients with hypertension, ACE inhibitor (aOR 1.37, 95% CI 0.61 to 3.08, p=0.61) and ARB (aOR 0.64, 95% CI 0.27 to 1.49, p=0.30) use was not associated with mortality. CONCLUSIONS: In patients hospitalised with COVID-19, pre-existing hypertension was the most prevalent comorbidity but was not independently associated with mortality. Similarly, the baseline use of ACE inhibitors or ARBs had no independent association with in-hospital mortality.

Cardiac Complications in Patients Hospitalised With COVID-19 in Australia.

OBJECTIVES: Describe the incidence of cardiac complications in patients admitted to hospital with COVID-19 in Australia. DESIGN: Observational cohort study. SETTING: Twenty-one (21) Australian hospitals. PARTICIPANTS: Consecutive patients aged ≥18 years admitted to hospital with laboratory confirmed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. MAIN OUTCOME MEASURES: Incidence of cardiac complications. RESULTS: Six-hundred-and-forty-four (644) hospitalised patients (62.5±20.1 yo, 51.1% male) with COVID-19 were enrolled in the study. Overall in-hospital mortality was 14.3%. Twenty (20) (3.6%) patients developed new atrial fibrillation or flutter during admission and 9 (1.6%) patients were diagnosed with new heart failure or cardiomyopathy. Three (3) (0.5%) patients developed high grade atrioventricular (AV) block. Two (2) (0.3%) patients were clinically diagnosed with pericarditis or myopericarditis. Among the 295 (45.8%) patients with at least one troponin measurement, 99 (33.6%) had a peak troponin above the upper limit of normal (ULN). In-hospital mortality was higher in patients with raised troponin (32.3% vs 6.1%, p<0.001). New onset atrial fibrillation or flutter (6.4% vs 1.0%, p=0.001) and troponin elevation above the ULN (50.3% vs 16.4%, p<0.001) were more common in patients 65 years and older. There was no significant difference in the rate of cardiac complications between males and females. CONCLUSIONS: Among patients with COVID-19 requiring hospitalisation in Australia, troponin elevation was common but clinical cardiac sequelae were uncommon. The incidence of atrial arrhythmias and troponin elevation was greatest in patients 65 years and older.

Impact of coronary artery bypass grafting (CABG) on coronary collaterals in patients with a chronic total occlusion (CTO).

Chronic total occlusions (CTO) are found commonly in patients with prior coronary artery bypass grafting (CABG). We sought to determine the effect of CABG on collateral robustness in patients with a CTO. Patients with a CTO diagnosed on coronary angiography between July 2010 and December 2019 were included in this study. Patients were classified as either CTO supplied by a functional graft, CTO supplied by collaterals from a non-grafted donor vessel (non-grafted) or a CTO supplied by collaterals from a grafted donor vessel (grafted). The degree of collateral robustness was determined by the Rentrop classification and collateral connection (CC) grade. Demographic, angiographic and clinical outcomes were recorded. A total of 2088 CTO lesions were identified, of which 878 (42.0%) were supplied by a functional graft, 994 (47.6%) CTOs were supplied by a non-grafted donor vessel and 216 (10.3%) CTOs were supplied by a grafted donor vessel. CTOs supplied by a grafted donor vessel had lower rates of robust collaterals (37.0% vs 83.0%, p < 0.0001) with less mature collaterals as determined by the Rentrop grade (p < 0.0001) and CC grade (p < 0.0001) as compared to CTOs supplied by a non-grafted donor vessel. In patients with a previous CABG, a grafted donor vessel results in less robust coronary collaterals with lower Rentrop and CC grade compared to an ungrafted donor vessel. This may be attributable to changes in coronary blood flow and shear stress, and may be a factor in the lower procedural success rates for CTO intervention in patients with prior CABG.

Safety and Efficacy of Leadless Pacemakers: A Systematic Review and Meta-Analysis.

Background Leadless pacemaker is a novel technology, and evidence supporting its use is uncertain. We performed a systematic review and meta-analysis to examine the safety and efficacy of leadless pacemakers implanted in the right ventricle. Methods and Results We searched PubMed and Embase for studies published before June 6, 2020. The primary safety outcome was major complications, whereas the primary efficacy end point was acceptable pacing capture threshold (≤2 V). Pooled estimates were calculated using the Freedman-Tukey double arcsine transformation. Of 1281 records screened, we identified 36 observational studies of Nanostim and Micra leadless pacemakers, with most (69.4%) reporting outcomes for the Micra. For Micra, the pooled incidence of complications at 90 days (n=1608) was 0.46% (95% CI, 0.08%-1.05%) and at 1 year (n=3194) was 1.77% (95% CI, 0.76%-3.07%). In 5 studies with up to 1-year follow-up, Micra was associated with 51% lower odds of complications compared with transvenous pacemakers (3.30% versus 7.43%; odds ratio [OR], 0.49; 95% CI, 0.34-0.70). At 1 year, 98.96% (95% CI, 97.26%-99.94%) of 1376 patients implanted with Micra had good pacing capture thresholds. For Nanostim, the reported complication incidence ranged from 6.06% to 23.54% at 90 days and 5.33% to 6.67% at 1 year, with 90% to 100% having good pacing capture thresholds at 1 year (pooled result not estimated because of the low number of studies). Conclusions Most studies report outcomes for the Micra, which is associated with a low risk of complications and good electrical performance up to 1-year after implantation. Further data from randomized controlled trials are needed to support the widespread adoption of these devices in clinical practice.

Classic adrenal adenoma undergoing necrosis secondary to chemotherapy for pancreatic adenocarcinoma.

Our patient was a 53-year-old male with borderline resectable pancreatic adenocarcinoma who on his initial staging CT and subsequent MRI was found to have an incidental adrenal adenoma. Following completion of six cycles of neoadjuvant chemotherapy over a three-month period, the patient returned for restaging. The adrenal nodule had increased in size and had undergone necrosis with just a fine cuff of residual viable lesion at the margins. It is thought that chemotherapeutic agents should not lead to significant cell death of an adrenal adenoma, and this produced diagnostic uncertainty. Interestingly, the lesion was subsequently biopsied under CT with histology confirming a classic adrenal adenoma. This rare case challenges our understanding of chemotherapeutic effects on adrenal adenomas, and offers another differential when assessing necrotic adrenal lesions.

Prognostic implications of the rapid recruitment of coronary collaterals during ST elevation myocardial infarction (STEMI): a meta-analysis of over 14,000 patients.

Acute coronary collateralisation of an infarct-related arterial (IRA) territory may be identified during angiography for ST elevation myocardial infarction (STEMI). Whether the presence or absence of these collaterals affects outcomes remains uncertain. A search of EMBASE, MEDLINE and Cochrane Library, using the Preferred Reporting Items for Systematic reviews and Meta-Analysis (PRISMA) guidelines was conducted to identify studies which reported on the association between coronary collaterals and in-hospital and longer term mortality, left ventricular ejection fraction (LVEF), risk of repeat acute myocardial infarction (AMI) and repeat revascularisation. Patients with Rentrop grade 0 or 1 were defined as poor collaterals whilst those with Rentrop grade two or three were defined as those with robust collaterals. Studies were eligible if they included patients ≥ 18 years of age who had immediate coronary angiography for STEMI. Included studies were observational which recorded the degree of collateral blood flow to the IRA. Two investigators reviewed all citations using a predefined protocol with final consensus for all studies, the data from which was then independently entered to ensure fidelity of results. Inverse variance random effects model for the meta-analysis along with risk of bias assessment was performed. 20 studies with a total of 14,608 patients were identified and included in the analysis. Patients with robust collaterals had lower mortality (OR 0.55, 95% CI 0.48-0.64), both in-hospital (OR 0.47, 95% CI 0.35-0.63) and longer term (OR 0.58, 95% CI 0.46-0.75). Patients with robust collaterals also had a higher mean LVEF (SMD 0.23, 95% CI 0.10-0.37). There was no difference in the rates of AMI or repeat revascularisation between patients with robust or poor collaterals. The presence of robust collaterals during STEMI is associated with reduced in-hospital and longer term mortality and improved left ventricular function. These findings have implications for prognostication and identifying patients who require close monitoring following STEMI.

Prognostic impact of collaterals in patients with a coronary chronic total occlusion: A meta-analysis of over 3,000 patients.

OBJECTIVES: To assess the prognostic implications of the degree of coronary collaterals on outcomes in patients with a CTO. BACKGROUND: Coronary chronic total occlusions (CTO) are identified frequently in patients undergoing coronary angiography and have been associated with poorer prognosis. Whether the degree of coronary collaterals, the hallmark of CTOs impacts prognosis, is unknown. METHODS: A search of EMBASE, MEDLINE, and Cochrane Library was conducted to identify studies reporting on coronary collaterals and risk of all-cause mortality, acute myocardial infarction (AMI) and successful percutaneous coronary intervention (PCI). Patients with Rentrop grade 0 or 1 collaterals were defined as poor collaterals, while Rentrop grade 2 or 3 were defined as robust collaterals. RESULTS: Twelve studies with a total of 3,369 were included. Patients with robust collaterals did not have lower rates of AMI (OR: 0.89, 95%CI: 0.39-2.04) or lower rates of all-cause mortality (OR: 0.81, 95% CI: 0.42-1.58), however were more likely to have successful PCI (OR: 4.04, 95%CI: 1.10-14.85). CONCLUSION: The presence of robust collaterals is not associated with lower rates of AMI or mortality, but does increase the likelihood of successful CTO PCI. These results have importance implications with respect to the indications for CTO PCI as well as selecting appropriate patients to undergo the procedure.

The indications and utility of adjunctive imaging modalities for chronic total occlusion (CTO) intervention.

Coronary chronic total occlusions (CTO) are common in patients undergoing coronary angiography, yet the optimal management strategy remains uncertain, with conflicting results from randomized trials. Appropriate patient selection and careful periprocedural planning are imperative for successful patient management. We review the role of adjunctive imaging modalities including myocardial perfusion imaging (MPI), cardiac magnetic resonance imaging (CMR), echocardiography and computed tomography coronary angiography (CTCA) in myocardial ischemic quantification, myocardial viability assessment, as well as procedural planning for CTO revascularization. An appreciation of the value, indications and limitations of these modalities prior to planned intervention are essential for optimal management.

Recruitment and maturation of the coronary collateral circulation: Current understanding and perspectives in arteriogenesis.

The coronary collateral circulation is a rich anastomotic network of primitive vessels which have the ability to augment in size and function through the process of arteriogenesis. In this review, we evaluate the current understandings of the molecular and cellular mechanisms by which this process occurs, specifically focussing on elevated fluid shear stress (FSS), inflammation, the redox state and gene expression along with the integrative, parallel and simultaneous process by which this occurs. The initiating step of arteriogenesis occurs following occlusion of an epicardial coronary artery, with an increase in FSS detected by mechanoreceptors within the endothelium. This must occur within a 'redox window' where an equilibrium of oxidative and reductive factors are present. These factors initially result in an inflammatory milieu, mediated by neutrophils as well as lymphocytes, with resultant activation of a number of downstream molecular pathways resulting in increased expression of proteins involved in monocyte attraction and adherence; namely vascular cell adhesion molecule 1 (VCAM-1), monocyte chemoattractant protein 1 (MCP-1) and transforming growth factor beta (TGF-ß). Once monocytes and other inflammatory cells adhere to the endothelium they enter the extracellular matrix and differentiate into macrophages in an effort to create a favourable environment for vessel growth and development. Activated macrophages secrete inflammatory cytokines such as tumour necrosis factor-α (TNF-α), growth factors such as fibroblast growth factor-2 (FGF-2) and matrix metalloproteinases. Finally, vascular smooth muscle cells proliferate and switch to a contractile phenotype, resulting in an increased diameter and functionality of the collateral vessel, thereby allowing improved perfusion of the distal myocardium subtended by the occluded vessel. This simultaneously reduces FSS within the collateral vessel, inhibiting further vessel growth.

Effect of Recruitment of Acute Coronary Collaterals on In-Hospital Mortality and on Left Ventricular Function in Patients Presenting With ST Elevation Myocardial Infarction.

Recruitment of the coronary collateral circulation is frequently observed during ST elevation myocardial infarction (STEMI) and is of uncertain significance. The aim of this study was to identify and determine the predictors and prognostic implications of the presence of robust collaterals during STEMI. All patients presenting to a large tertiary centre with a STEMI undergoing percutaneous coronary intervention from 2010 to 2018 were reviewed. Patients with poor collateral recruitment were defined as those with Rentrop grade 0 or 1 collaterals, whilst patients with robust collateral recruitment were defined as Rentrop grade 2 or 3. A total of 1,625 patients were included in the study, with 1,280 (78.8%) patients having poor collateral recruitment and 345 patients (21.2%) having robust collateral recruitment. Patients with robust collaterals were younger (63.1 vs 65.1 years, p < 0.05), had a longer ischemic time (628.5 minutes vs 433.1 minutes, p < 0.0001), and more likely to have a chronic total occlusion of a noninfarct related artery (10.4% vs 5.3%, p < 0.001). The presence of robust collaterals was associated with higher rates of normal or mildly impaired left ventricular function (83.5% vs 63.2%, p < 0.0001) and lower in-hospital mortality (2.1% vs 7.6%, p < 0.0001). After correcting for left ventricular function, collateral recruitment was not an independent predictor of mortality. In conclusion, in patients presenting with STEMI, the presence of robust coronary collaterals appears to be associated with improved left ventricular function. Further research is required to identify mechanisms of collateral maturation and recruitment.

Interference Between Pressure-Wire and Deployed Coronary Stents: Insights from a Bench Test.

BACKGROUND: While several complications related to pressure-wire (PW) have been reported, mechanistic justification has not always been offered. Furthermore, interference between a PW and a protruding side-branch stent has not been previously reported. The purpose of this study was to evaluate interference between PW-pullback from a main-branch with a protruded ostial stent deployed in a side-branch. METHODS: In a polyurethane bifurcation vessel model, PW-pullback was performed in a main-branch following protruded ostial stenting in a side-branch. Tested PWs included PressureWire X, Comet, OptoWire, and Verrata. For each PW, pullback was performed through the same proximal cell of the protruded stent 20 times. Interference during PW-pullback was objectively analyzed with a fiberscope placed at the distal main-branch and classified into 3 grades according to the interaction with stent strut. RESULTS: There were significant differences in the rate of interference between the PWs. No-interference, interference without strut traction, and interference with strut traction (i.e. stent deformation) were observed as follows: 17/20, 3/20, and 0/20 in PressureWire X; 19/20, 1/20, and 0/20 in Comet; 8/20, 10/20, and 2/20 in OptoWire; and 13/20, 2/20, and 5/20 in Verrata, respectively (p for any differences: <0.001). Visually identifiable major stent deformation was observed once in OptoWire due to the deep concave sensor window and twice in Verrata due to the proximal gap between the sensor and coiled-wire. CONCLUSIONS: PW-pullback in the main-branch after side-branch ostial stenting should be carefully performed to avoid stent deformation. Consideration on the specific mechanical features of the PW is also essential.

Radioactive iodine ablation post differentiated thyroid cancer surgery: an analysis of use and impact of the American Thyroid Association guidelines.

BACKGROUND: The 2009 American Thyroid Association (ATA) three-tiered risk stratification, and its updated version in 2015, provided clearer guidance on the use of radioactive iodine (RAI) ablation in differentiated thyroid cancer (DTC) patients. This study examines the impact of these guidelines on RAI use in our institution. METHODS: Patients diagnosed with DTC during three different time periods (group 1: 2002-2006, group 2: 2010-2014 and group 3: 2017-2018) were identified and risk stratified according to the ATA guidelines. RAI use and extent of surgery were compared between the three groups. Categorical variables were analysed using Fisher's exact (2 × 2) and chi-squared (>2 × 2) tests. RESULTS: A total of 415 patients were included (group 1 = 88, group 2 = 215, group 3 = 112). The proportion of patients having total thyroidectomy were 84.6, 84.7 and 69.6% in groups 1, 2 and 3, respectively (P = 0.003). Central lymph node dissection was significantly higher in the more contemporary groups compared to group 1 (9.1 versus 41.9 versus 64.3%, P < 0.001). Overall, fewer patients received RAI in more recent times (76.6 versus 54.8 versus 26.8%, P < 0.001), most evident in the low-risk patients (70 versus 29.1 versus 5.1%, P < 0.001). In the high risk group, the majority received RAI, with no difference between the groups. CONCLUSION: Comparing DTC patients treated in our unit before and after publications of the 2009 and 2015 ATA guidelines, more nodal surgery was performed with less RAI administered in the latter groups. Better risk stratification according to the ATA guidelines has allowed more judicious use of RAI ablation.