High output cardiac state: evaluating the incidence, plausible etiologies and outcomes.

INTRODUCTION: The high output cardiac state (HOCS) [cardiac index (CI) >4 L/min/m2 ], primarily driven by abnormally low systemic vascular resistance (SVR), is a relatively under-recognized condition. Although, majority of these patients meet criteria for heart failure (HF), their treatment should be aimed at the primary pathology, as the majority of guideline directed HF therapies can reduce SVR further. OBJECTIVES: To characterize patients with HOCS and provide valuable insight into the condition. METHODS: Patients investigated by right heart catheterization (RHC) at the St. Boniface Hospital, Winnipeg, Canada between January 2009 and November 2021 were reviewed. Two groups of patients were included: 1) HOCS [CI >4 L/min/m2], and 2) pre-HOCS [CI between 3.8-4.0 L/min/m2]. Their medical records were reviewed to identify plausible etiologies, relevant investigations, and outcomes. RESULTS: 177/2950 (6 %) patients met criteria for inclusion: 144/177 (81 %) with HOCS [mean age 51 years (range 19 - 82); 67/144 (47 %) female] and 33/177 (19 %) with pre-HOCS [mean age 55 years (range 30 - 83); 6/33 (18 %) female]. The most common plausible etiologies for the HOCS included anemia (36 %), obesity (34 %), cirrhosis (17 %), and lung disease (32 %). Trans-thoracic echocardiography and magnetic resonance imaging findings were non-specific and predominantly described preserved left ventricular ejection fraction, and pulmonary hypertension. The population experienced high rates of hospitalization, and significantly high mortality [36/144 (25 %) of HOCS at a median follow-up of 31.5 months, and 13/33 (39 %) of pre-HOCS at a median follow-up of 17 months]. CONCLUSIONS: HOCS is not an uncommon condition and is associated with high mortality. Current HF guideline should incorporate such evaluation into the diagnostic criteria.

Increasing rates of screening and treatment of iron deficiency in ambulatory patients with heart failure with reduced ejection fraction: a quality improvement cohort study.

INTRODUCTION: Iron deficiency anaemia (IDA) is common in patients with heart failure (HF) and is associated with advanced HF and increased mortality. Intravenous iron supplementation increases exercise tolerance, improves quality of life, and decreases symptoms among patients with HF with reduced ejection fraction (HFrEF) and iron deficiency. Despite this, many patients are not screened or treated for IDA. We aimed to increase rates of screening and treatment of IDA among HF patients through the introduction of curated materials to aid HF clinicians with appropriate screening and treatment. METHODS: We conducted a retrospective chart review to identify the baseline number of HFrEF patients screened and treated for IDA at two ambulatory cardiology clinics in Toronto, Ontario. A quality improvement initiative was then introduced, which consisted of education and curated materials to aid clinicians in the screening and treatment of IDA among HFrEF patients. The proportion of patients screened and treated for IDA preintervention and postintervention were compared using χ2 tests of Independence. RESULTS: In the preintervention cohort, 36.3% (n=45) of patients with anaemia were screened for IDA. Among those screened, 64.4% (n=29) had IDA. Only 17.2% (n=5) of these were treated with IV iron. After implementation of the quality improvement initiative, 90.9% (n=60) of patients with anaemia were screened for IDA (p<0.001) and 90.3% (n=28) of those with IDA were treated with IV iron (p<0.001). CONCLUSION: The introduction of curated materials to aid clinicians was associated with increased rates of screening and treatment of IDA among ambulatory HFrEF patients. Further work is required to identify barriers and implement strategies to increase screening and treatment rates of IDA among HFrEF patients.

Aortic luminal remodeling after intravascular stent therapy for coarctation of the aorta: intermediate results.

OBJECTIVE: Outcomes after adult coarctation of the aorta (CoA) stenting is scant. We explored predictors of aortic remodeling after stent implantation and report early- and intermediate-term clinical outcomes. METHODS: Adult patients who underwent stenting between July 2003 and December 2017 were included in this single-center retrospective study. We created a novel index of aortic volumetric and diameter changes using computed tomography (CT)/magnetic resonance (MR) images measured through TeraRecon and AngioQ. Predictors of aortic remodeling were explored using univariable linear regression analysis. RESULTS: One hundred and thirty-four patients (mean age 35.2 years, 58.2% men) underwent CoA stenting. Paired aortic diameter measurements were available in 20 patients, and 40 paired patients in volumetric measurements. There was significant reduction in aortic diameter immediately proximal to the left carotid and subclavian arteries, and the aorta distal to the stenosis (P less than .05) at follow-up. There was a significant volumetric reduction in the ascending aorta, aortic arch, and the aortic segment most proximal to the top of the stent (P less than .05). Univariate predictors of aortic remodeling included sex, age, presence of previous surgical repair, aortic valve morphology, and the number of antihypertensive medications. Mean follow-up time was 4.0 ± 3.8 years, where 5% of patients underwent reintervention due to complications, 3% developed aneurysms, and 3% had stent fractures. CONCLUSIONS: This study is the first to examine the anatomical changes that occur in the aorta post stent repair through analysis of serial imaging. Patients with stent-repaired coarctation demonstrated negative remodeling in multiple areas of the aorta with regards to the aortic diameter and volumetric measurements.

Real-world outcomes in treatment of highly calcified coronary lesions with intravascular shockwave lithotripsy.

Real-world data regarding the efficacy and safety of coronary intravascular lithotripsy (IVL) are lacking. We conducted a study of 50 consecutive patients (64 lesions) who underwent IVL. 3 patients suffered in-hospital mortality unrelated to the IVL; there was no other occurrence of MACE up to 30 days. Angiographic success was nearly universal (98% of patients with residual stenosis <50%, 96% of patients with TIMI 3 flow) and complication was rare, including among patients undergoing IVL for in-stent restenosis or left main coronary artery lesions. In a high-risk real-world cohort, IVL was a safe and effective treatment for highly-calcified coronary lesions.

Did Collagen Cross-Linking Reduce the Requirement for Corneal Transplantation in Keratoconus? The Canadian Experience.

PURPOSE: To investigate the relationship between corneal collagen cross-linking (CXL) and the number of corneal transplants required for the treatment of keratoconus (KCN) in 2 major Canadian provinces. METHODS: This is a retrospective review of all corneal transplantation performed in Ontario and British Columbia over an 18-year period (1998-2016). Data were collected at the Eye Bank of Canada-Ontario/British Columbia Divisions. The primary outcome was to determine the change in proportion and absolute number of corneal transplants required for treatment of KCN since the introduction of CXL in Canada in 2008. RESULTS: A total of 31,943 grafts were included. Overall, the mean age of participants was 39.3 ± 2.2 years, with our cohort being composed of 28% of women and 72% of men. The results showed a significant decrease in the proportion of total transplants required for KCN between 1998 and 2016 [1998-2008 (pre-CXL), range: 14.77%-12.63%; 2009-2016 (post-CXL), range: 12.98%-5.50%, P < 0.001]. However, there was no change in the absolute number of grafts performed for KCN over this time (pre-CXL: 179 ± 26 grafts; post-CXL: 198 ± 27 grafts; P = 0.5), whereas the total number of grafts (pre-CXL: 1318 ± 183 grafts; post-CXL: 2181 ± 404; P < 0.001) and endothelial keratoplasties (pre-CXL: 59 ± 108; post-CXL: 966 ± 431 grafts; P < 0.001) increased significantly. In addition, there were no changes in penetrating keratoplasty/deep anterior lamellar keratoplasty (DALK) performed for indications other than KCN (pre-CXL: 1080 ± 157; post-CXL: 1017 ± 92; P > 0.5). CONCLUSIONS: Although there has been a significant decrease in the proportion of corneal graft rates for KCN since the introduction of CXL as a factor of all transplants performed for all indications, this result is most likely because of an increase in endothelial keratoplasties rather than decreased transplants performed for definitive treatment.

Dataset of red light induced pupil constriction superimposed on post-illumination pupil response.

We collected and analyzed pupil diameter data from of 7 visually normal participants to compare the maximum pupil constriction (MPC) induced by "Red Only" vs. "Blue+Red" visual stimulation conditions. The "Red Only" condition consisted of red light (640±10 nm) stimuli of variable intensity and duration presented to dark-adapted eyes with pupils at resting state. This condition stimulates the cone-driven activity of the intrinsically photosensitive retinal ganglion cells (ipRGC). The "Blue+Red" condition consisted of the same red light stimulus presented during ongoing blue (470±17 nm) light-induced post-illumination pupil response (PIPR), representing the cone-driven ipRGC activity superimposed on the melanopsin-driven intrinsic activity of the ipRGCs ("The Absence of Attenuating Effect of Red light Exposure on Pre-existing Melanopsin-Driven Post-illumination Pupil Response" Lei et al. (2016) [1]). MPC induced by the "Red Only" condition was compared with the MPC induced by the "Blue+Red" condition by multiple paired sample t-tests with Bonferroni correction.

The absence of attenuating effect of red light exposure on pre-existing melanopsin-driven post-illumination pupil response.

It has been proposed that after activation by blue light, activated melanopsin is converted back to its resting state by long wavelength red light exposure, a putative mechanism of melanopsin chromophore recovery in vivo. We tested this hypothesis by investigating whether red light attenuates the ongoing post-illumination pupil response (PIPR) induced by melanopsin-activating blue light. Pupillary light responses were tested using "Blue+Red" double flashes and "Blue Only" single flash stimuli in 10 visually normal subjects. For "Blue+Red" conditions, PIPR was induced with an intense blue flash, followed by experimental red light exposure of variable intensity and duration (Experiment 1) immediately or 9s after the offset of the blue flash (Experiment 2). For "Blue Only" conditions, only the PIPR-inducing blue stimuli were presented (reference condition). PIPR was defined as the mean pupil size from 10 to 30s (Experiment 1) and from 25 to 60s (Experiment 2) after the offset of blue light stimuli. The results showed that PIPR from "Blue+Red" conditions did not differ significantly from those of "Blue Only" conditions (p=0.55) in Experiment 1. The two stimulation conditions also did not differ in Experiment 2 (p=0.38). We therefore conclude that red light exposure does not alter the time course of PIPR induced by blue light. This finding does not support the hypothesis that long wavelength red light reverses activated melanopsin; rather it lends support to the hypothesis that the wavelengths of stimuli driving both the forward and backward reactions of melanopsin may be similar.

Adaptation to Laterally Displacing Prisms in Anisometropic Amblyopia.

PURPOSE: Using visual feedback to modify sensorimotor output in response to changes in the external environment is essential for daily function. Prism adaptation is a well-established experimental paradigm to quantify sensorimotor adaptation; that is, how the sensorimotor system adapts to an optically-altered visuospatial environment. Amblyopia is a neurodevelopmental disorder characterized by spatiotemporal deficits in vision that impacts manual and oculomotor function. This study explored the effects of anisometropic amblyopia on prism adaptation. METHODS: Eight participants with anisometropic amblyopia and 11 visually-normal adults, all right-handed, were tested. Participants pointed to visual targets and were presented with feedback of hand position near the terminus of limb movement in three blocks: baseline, adaptation, and deadaptation. Adaptation was induced by viewing with binocular 11.4° (20 prism diopter [PD]) left-shifting prisms. All tasks were performed during binocular viewing. RESULTS: Participants with anisometropic amblyopia required significantly more trials (i.e., increased time constant) to adapt to prismatic optical displacement than visually-normal controls. During the rapid error correction phase of adaptation, people with anisometropic amblyopia also exhibited greater variance in motor output than visually-normal controls. CONCLUSIONS: Amblyopia impacts on the ability to adapt the sensorimotor system to an optically-displaced visual environment. The increased time constant and greater variance in motor output during the rapid error correction phase of adaptation may indicate deficits in processing of visual information as a result of degraded spatiotemporal vision in amblyopia.