Characterizing left ventricular stiffness in women with signs and symptoms of ischemia with no obstructive coronary arteries

Background

Women with signs and symptoms of ischemia and no obstructive coronary arteries (INOCA) have evidence of diastolic dysfunction and are at increased risk of developing heart failure with preserved ejection fraction (HFpEF). However, mechanisms contributing to HFpEF development are poorly understood and often attributed to underlying cardiovascular risk factors.

Purpose

To compare clinical, invasive, and imaging parameters in women with suspected INOCA and various degrees of left ventricular (LV) stiffness (as measured by invasive end-diastolic pressure [EDP]/end diastolic volume [EDV]).

Methods

Women with suspected INOCA underwent invasive LV pressure-volume loop analysis at rest and coronary function testing with a Doppler wire in the left anterior descending artery. Intracoronary vasoactive substances (adenosine, acetylcholine, nitroglycerin) were infused into the left main artery, as published. Rest and adenosine stress cardiac magnetic resonance (CMR) imaging was performed to evaluate LV function, structure, perfusion, and fibrosis. Women in different tertiles of EDP/EDV ratio were compared using t-tests.

Results

A total of 62 women with complete invasive data were included; 2 did not complete CMR. Compared to the lower EDP/EDV tertile, women in the upper tertile were older, had higher ejection fraction, higher mass/volume ratio, worse diastolic function, greater aortic stiffness and worse coronary microvascular function (Table 1). Traditional cardiovascular risk factors were not significantly different.

Conclusion

Among women with INOCA, older age, coronary microvascular dysfunction, and aortic stiffness were related to greater LV stiffness at rest. Those with the highest EDP/EDV ratio had hyperdynamic LV systolic function and the smallest LV size. More work is needed to understand contribution of coronary microvascular dysfunction to HFpEF progression.

Funding Acknowledgement

Type of funding sources: Other. Main funding source(s): National Institutes of HealthErika Glazer Women's Heart Health Project

P2715Diastolic dysfunction in women with ischemia and no obstructive coronary artery disease: novel insight from left atrial feature tracking

Background

Women with signs and symptoms of ischemia but no obstructive coronary artery disease (INOCA) are at increased risk of developing heart failure with preserved ejection fraction (HFpEF); however, the exact mechanism for HFpEF progression remains to be elucidated. Prior studies have focused specifically on impaired left ventricular diastolic function in INOCA. We hypothesized that extending our evaluation to include the left atrium (LA)– a key constituent of the transmitral pressure gradient and left ventricular filling– would provide additional, novel, pathophysiological insight.

Purpose

To evaluate LA function in women with INOCA using cardiac MRI (CMR).

Methods

We performed retrospective feature tracking analysis of cine images from CMR (Figure 1A), to evaluate LA strain, in 58 INOCA women with normal sinus rhythm (three were excluded due to suboptimal image quality). All strain measurements were performed in duplicate by an experienced investigator blinded to clinical status. We subdivided the cohort by an established threshold of resting left ventricular end diastolic pressure (LVEDP) <12 mmHg vs >12 mmHg, performed invasively within a median of 27 days of the CMR. As illustrated in Figure 1B, LA function was divided into three established phases: (1) reservoir strain, passive expansion of the left atrium from the pulmonary circulation while the mitral valve is closed; (2) conduit strain, passive emptying of the atrium into the ventricle; and (3) booster strain, active emptying of the left atrium following atrial depolarization.

Results

Reservoir strain was higher in the elevated LVEDP group (n=20, 26.1 + 1.3%) vs. not elevated group (n=35, 22.8 + 0.9%, p=0.03; Figure 1C). In contrast, we observed no group difference in conduit strain (16.5 + 1.0 and 16.5 + 0.7, p=0.78, respectively; Figure 1D), resulting in significantly higher atrial booster strain in the elevated LVEDP group (10.0 + 1.1% and 7.0 + 0.6, p<0.01, respectively; Figure 1E).

Conclusions

To our knowledge, this is the first report of LA function in women with INOCA. That reservoir strain was higher in subjects with elevated LVEDP provides important pathophysiologic insight regarding diastolic hemodynamics of the LA. The similar conduit function between groups– despite different LVEDP's– strongly suggests a ventricular contribution to the impaired transmitral pressure gradient. Together, these initial proof-of-concept data support the evaluation of LA function in our quest to better understand heart failure progression in INOCA.

Modelling positive consequences: Increased vegetable intakes following modelled enjoyment versus modelled intake

OBJECTIVE

Modelling has previously been demonstrated to encourage healthy eating, but the importance of modelling the behaviour versus modelling the positive consequences of the behaviour is unknown. This work investigated the impact of modelling carrot intake (the behaviour) and modelling carrot enjoyment (the positive consequences) on subsequent liking and consumption of carrots and sweetcorn.

METHODS

155 children aged 7-10 years were randomized to hear a story where fictional characters consumed a picnic with either: no mention of carrot sticks (control) (N = 45); mention of carrot sticks that all characters ate (modelling intake) (N = 60); or mention of carrot sticks that the characters like (modelling enjoyment) (N = 50). Carrot and sweetcorn liking and intake were measured before and after the story during a 5 min task.

RESULTS

Carrot liking and intake after a story were higher following the story modelling carrot enjoyment compared to the stories not modelling enjoyment (smallest β = 0.16, p = 0.05), and in those with higher pre-story carrot liking and intake (smallest β = 0.25, p < 0.01). Sweetcorn liking and intake after a story were associated with pre-story sweetcorn liking and intake (smallest β = 0.28, p < 0.01), and sweetcorn intake was lower following the story modelling carrot enjoyment compared to the stories not modelling enjoyment (β = -0.17, p = 0.04).

CONCLUSIONS

These findings demonstrate a role for modelling enjoyment to encourage vegetable liking and intake, although effects sizes were small. These findings also suggest a benefit from modelling the positive consequences of a behaviour for encouraging healthy food intake in children, while limited effects were found for modelling the behaviour itself.

Asian and Pacific Migration: The Canadian Experience

On a per capita basis, Canada currently accepts more immigrants than any other country in the world. This article examines the characteristics of landed immigrants (permanent settlers) from Asia and explores their settlement, adaptation, and integration experience. Asian immigration has grown by leaps and bounds since the universalization of Canadian immigration policy. The skills content, capital inflow, and entrepreneurial impacts of Asian immigration have been significant. Generally speaking, Asian immigrants have adapted and integrated well. Yet access to Canadian territory as permanent residents, or access to Canadian citizenship, does not necessarily mean access to equal opportunity in the economy and society, though to a certain extent, Canada may have succeeded more than Australia.

India-born Immigrants in Australia and Canada: A Comparison of Selected Characteristics

"This article examines the Indian component of Asian immigration to Canada and Australia, reviews briefly the historical background of Indian immigration, discusses the characteristics of India-born immigrants and explores their social impact upon both nations. A comparative approach is adopted to highlight similarities and differences." (SUMMARY IN FRE AND SPA)

The labour market experiences of Canadian immigrants

The economic adaptation of immigrants to Canada is analyzed using government data on the labor force and landed immigrants. In particular, the labor force experience of a sample of immigrants in Canada is examined and compared with that of a Canadian cohort with regard to length of unemployment and income. "Differences in unemployment and insurable earnings are examined by age, sex, immigrant category..., world area of last permanent residence, official language abilities, education, and region of residence." (summary in FRE, SPA)