Dr. Annie Chou's Research and Publications

Scentific Journal Publications:

Chou AY, Liu Chia-Jen, Chao Tze-Fan, et al. Presence of diabetic microvascular complicaitons does not incrementally increase risk of ischemic stroke in diabetic patients with atrial fibrillation: A nationwide cohort study. Medicine 2016;95(27):e3992.

Conventional stroke risk prediction tools used in atrial fibrillation (AF) incorporate the presence of diabetes mellitus (DM) as a risk factor. However, it is unknown whether this risk is homogenous or dependent on the presence of diabetic microvascular complications, such as diabetic retinopathy, nephropathy, and neuropathy. The present study examined the risk of ischemic stroke in diabetic patients with and without microvascular complications. The present study used the National Health Insurance Research Database in Taiwan with detailed healthcare data on all-comers to the Taiwanese medical system from January 1, 1996 to December 31, 2011. AF and DM were identified when listed as discharge diagnoses or confirmed more than twice in the outpatient department. Patients on antithrombotic agents were excluded. The clinical endpoint was ischemic stroke. Among the 50,180 AF patients with DM, the majority had no microvascular complications (72.7%), while 2.6% had diabeticretinopathy, 8.4% had diabetic nephropathy, and 16.1% had diabetic neuropathy. Ischemic stroke occurred in 6003 patients, with a 4.74% annual risk of ischemic stroke. When compared with DM patients without microvascular complications, those with diabeticretinopathy, nephropathy, or neuropathy had higher incidences of ischemic stroke (4.65 vs 5.07, 4.77, or 5.20 per 100 person-years, respectively). However, after adjusting for confounding factors, the differences were no longer significant. In a large nationwide AF cohort with DM, risk of ischemic stroke was similar between patients with and without microvascular complications, suggesting that risk stratification of these patients does not require inclusion of diabetic retinopathy, nephropathy, and neuropathy.

Chou AY, Saw J. Basis for Sex-Specific Expression of Takotsubo Cardiomyopathy, Cardiac Syndrome X, and Spontaneous Coronary Artery Dissection. Can J Cardiol 2014;30(7):738-46.

Takotsubo cardiomyopathy, cardiac syndrome X, and spontaneous coronary artery dissection are cardiovascular syndromes with a predilection for women. A complex interplay between neurohormonal factors, genetic influences, anatomic alterations, and other factors together affect cardiovascular function. Specifically, a high, variable, or deficient estrogen state leads to vasomotor instability with propensity toward vasoconstriction and endothelial dysfunction that predispose women to myocardial impairment, microvascular dysfunction, and coronary arterial wall instability. As the predominant sex hormone in women, fluctuating estrogen levels lead to a sex disparity in the expression of these cardiac entities. This review explores the research on sex-based differences of the neurohormonal, genetic, and mechanical factors in the normal cardiovascular system and in the pathophysiology of these 3 conditions. The understanding of their prevalence, pathogenesis, and sex disparity allows improved recognition, management, and support of female patients inflicted with these syndromes.

Chou AY, John Mancini GB. Warfarin Monotherapy in Atrial Fibrillation Patients with Stable Coronary Disease One Year Post Myocardial Infarction/Stent: Two Birds with One Stone? Can J Cardiol 2015;31(8):1070-2.

Patients with atrial fibrillation and stable coronary artery disease remain a therapeutic challenge because of the different antithrombotic therapies for the 2 conditions and the increase in bleeding with concomitant antiplatelet and anticoagulant medications. Current guidelines extrapolated data from studies of antithrombotic regimens of each condition separately but there is limited evidence for the optimal regimen in patients with atrial fibrillation and stable coronary artery disease beyond the first year after an acute coronary syndrome or stent implantation. In this review we suggest that warfarin monotherapy is sufficient for this patient population beyond 1 year.

Chou AY, Sedlak T, Aymong E, Sheth T, Starovoytov A, Humphries KH, Mancini GJ, Saw J. Spontaneous Coronary Artery Dissection Misdiagnosed as Takotsubo Cardiomyopathy – A Case Series. Can J Cardiol 2015;31(8):1073.e5-8.

Spontaneous coronary artery dissection (SCAD) and Takotsubo cardiomyopathy (TTC) can both cause myocardial infarction with subsequent normalization of wall motion abnormality. Angiograms of patients with TTC at Vancouver General Hospital were reviewed for SCAD. Clinical and investigational characteristics were recorded. Nine women with nonatherosclerotic SCAD were misdiagnosed as having TTC. Their average age was 55 years. Five patients had hypertension and 4 had emotional or physical stress. Fibromuscular dysplasia was present in 4 women. Wall motion abnormalities corresponded to dissected artery location and subsequently resolved. SCAD should be included in the differential diagnosis of patients suspected of having TTC and coronary angiograms scrutinized for subtle SCAD.

Chakrabarti S, Chou AY, Andrade JG, Bennett MT, Deyell MW, Tung SK, Krahn AD. Real-time Transmission to Real-time Patient Care: A Tale of 4 Devices. Can J Cardiol 2013;29(8):1014.e1-2.

We report a case in which a patient with dilated cardiomyopathy presented with syncope, terminated by a shock from his implantable cardioverter defibrillator. However, subsequent interrogation of the device revealed no tachycardia detection or treatment parameters. The mystifying details of the case were unravelled by remote consultation with the staff electrophysiologist and the use of smart phone-transmitted live images. This case highlights the use of mobile phone-facilitated video conferencing in urgent management of intracardiac device therapy. Judicious use of this technology has the potential to deliver effective and cost-effective solutions for many device-related emergencies in patients at remote settings.

Chou AY, Prakash R, Rajala J, Birnie T, et al. Dedicated Cardiac Rehabilitation Program for Patients with Spontaneous Coronary Artery Dissection. Can J Cardiol 2016 [In Press Accepted Manuscript].

Spontaneous coronary artery dissection (SCAD) is an important cause of myocardial infarction (MI) in young women. SCAD survivors are at risk of recurrent SCAD and thus, standard cardiac rehabilitation (CR) program may not be suited for this cohort. We designed a SCAD-specific CR protocol at Vancouver General Hospital to address the unique exercise and psychosocial needs of this patient cohort.

Li CH, Liu, CJ, Chou AY, et al. European Society of Cardiology Guideline-Adherent Antithrombotic Treatment and Risk of Mortality in Asian Patients with Atrial Fibrillation. Nature Scientific Reports 2016;6(30734):doi:10.1038/srep30734.

This study compared the risk of mortality in atrial fibrillation (AF) patients treated adherent to the 2012 European Society of Cardiology (ESC) guidelines for stroke prevention and those who were not treated according to guideline recommendations. This study used the Taiwan National Health Insurance

Research Database. From 1996 to 2011, 354,649 newly diagnosed AF patients were identified as the study population. Among the study cohort, 45,595 and 309,054 patients were defined as Guideline-Adherent and Non-Adherent groups, respectively. During the follow up of 1,480,280 person-years,

133,552 (37.7%) patients experienced mortality. The risk of mortality was lower among AF patients whose treatment was adherent to the guideline recommendation for stroke prevention than those whose treatment was not (annual risk of mortality = 4.3% versus 10.0%) with an adjusted hazard ratio

of 0.62 (95% confidence interval = 0.61–0.64, p value < 0.001) after adjusting for age, gender, CHA2DS2-VASc score and antiplatelet therapy. The findings were consistently observed after propensity matching analysis. In conclusion, the risk of mortality was lower for AF patients who were treated according to

the antithrombotic recommendations of the 2012 ESC guidelines, guided by the CHA2DS2-VASc score. Better efforts to implement guidelines would lead to improved outcomes for patients with AF.

Rayner-Hartley E, Chou AY, Saw J, Sedlak T. A case of Kounis Type I in a young female with Samter’s triad. Can J Cardiol 2015 [In Press Accepted Manuscript].

Kounis syndrome is defined as an acute coronary syndrome triggered by allergic or hypersensitivity reactions resulting in mast cell and platelet activation. Numerous causes have been described including various drugs, medical conditions and environmental exposures. Samter’s triad consists of nasal polyps, asthma and aspirin (or NSAID) sensitivity. We describe a case of Kounis type I in a young female with Samter’s triad presenting with cardiac arrest on three occasions. Ergonovine provocation testing established the diagnosis of coronary vasospasm. The patient has derived significant benefit from calcium channel blockers.

Brotto LA, Chou AY, Singh T, Woo, JST. Reproductive Health Practices among Indian, East Asian, and Canadian Women: The Role of Acculturation. JOGC 2008;30(3):229-38.

Canadian women show reproductive health behaviours and knowledge that is superior to Indian women. Moving to a western culture did not influence Indian women’s Pap testing behaviour; however, the fact that the reproductive health knowledge of Indian women who moved to Canada was better than that of women in India suggests that there may be a knowledge-behaviour desynchrony in this group of women. Efforts targeted at ethnic minority groups that aim to improve reproductive health knowledge and behaviours are greatly needed.

Abstract Only:

Chou AY, Wong GC, Gao M, Park J, Taylor CM, Ramanathan K. Microvascular Dysfunction in Patients with ST-Elevation Myocardial Infarction after Primary Percutaneous Coronary Intervention: No Sex Disparity.

We used ST-E recovery on ECGs pre and post PPCI to study potential sex differences in microvascular dysfunction, in conjunction with cardiac events in a STEMI population. Female STEMI patients were older, had more incomplete ST-E recovery after PPCI and had more in-hospital cardiac events, although significance was lost after adjusting for age.

Chou AY, Wong GC, Gao M, Park J, Toma M, Ramanathan K. Correlation of Cardiac Risk Factors with Incomplete ST-Elevation Recovery and In-Hospital Adverse Outcomes After Primary Percutaneous Coronary Intervention in a STEMI Population

Patients with ST-elevation myocardial infarction (STEMI) remain at risk of in-hospital cardiac events despite a successful primary percutaneous coronary intervention (PPCI). Cardiac risk factors have been hypothesized to correlate with less favourable outcomes. The degree of ST-elevation recovery on the electrocardiogram (ECG) post-PPCI is associated with subsequent cardiac events. We examined the correlation of established cardiac risk factors with incomplete ST-elevation recovery and outcomes in a STEMI population treated with PPCI.

Chou AY, Wong GC, Gao M, Lau B, Ramanathan K. Different ST-Segment Recovery Measures on ECGs Before and After Percutaneous Coronary Intervention Predict In-Hospital Adverse Outcomes in a STEMI Population

We used the widely available electrocardiogram (ECG) to study the association of ST segment recovery pre and post PPCI with cardiac events in a contemporary STEMI population. The majority of STEMI patients had ST-depression in addition to ST-elevation at STEMI diagnosis. Recovery of both ST-elevation and depression after PPCI correlated strongly with subsequent in-hospital cardiac events and may provide additional prognostic information compared with ST-elevation recovery.

Presentations:

Chou AY. American Heart Association Updates – Dual Antiplatelet Therapy (DAPT) Trial and Related Studies. UBC Cardiology Continuing Medical Education Session: Vancouver, British Columbia, Canada; December 1, 2014.

Chou AY, Wong GC, Gao M, Park J, Taylor CM, Ramanathan K. Microvascular Dysfunction in Patients with ST-Elevation Myocardial Infarction after Primary Percutaneous Coronary Intervention: No Sex Disparity [Poster]. American Heart Association Scientific Sessions 2014: Chicago, Illinois, USA; November 15-19, 2014.

Chou AY, Sedlak T, Aymong E, Starovoytov A, Humphries K, Mancini GBJ, Saw J. Spontaneous Coronary Artery Dissection Misdiagnosed as Takotsubo Cardiomyopathy – A Case Series [Oral Abstract]. Canadian Cardiovascular Congress 2014: Vancouver, British Columbia, Canada; October 25-28, 2014.

Chou AY, Wong GC, Gao M, Park J, Toma M, Ramanathan K. Correlation of Cardiac Risk Factors with Incomplete ST-Elevation Recovery and In-Hospital Adverse Outcomes After Primary Percutaneous Coronary Intervention in a STEMI Population [Oral Abstract]. Canadian Cardiovascular Congress 2014: Vancouver, British Columbia, Canada; October 25-28, 2014.

Chou AY, Rajala J, Birnie T, Isserow S, Taylor CM, Ignaszewski A, Chan S, Humphries K, Mancini GBJ, Sedlak T, Saw J. Cardiac Rehabilitation Protocol for Patients with Spontaneous Coronary Artery Dissection [Poster]. Canadian Cardiovascular Congress 2014: Vancouver, British Columbia, Canada; October 25-28, 2014.

Chou AY, Wong GC, Gao M, Park J, Taylor CM, Ramanathan K. Microvascular Dysfunction in Patients with ST-Elevation Myocardial Infarction after Primary Percutaneous Coronary Intervention: No Sex Disparity [Poster]. Canadian Cardiovascular Congress 2014: Vancouver, British Columbia, Canada; October 25-28, 2014.

Chou AY, Rajala J, Birnie T, Isserow S, Taylor CM, Ignaszewski A, Chan S, Humphries K, Mancini GBJ, Sedlak T, Saw J. Cardiac Rehabilitation Protocol for Patients with Spontaneous Coronary Artery Dissection [Poster]. Transcatheter Cardiovascular Therapeutics 2014: Washington, DC, USA; September 13-17, 2014.

Chou AY, Wong GC, Gao M, Park J, Taylor CM, Ramanathan K. Microvascular Dysfunction in Patients with ST-Elevation Myocardial Infarction after Primary Percutaneous Coronary Intervention: No Sex Disparity [Poster]. UBC Cardiac Sciences Research Day 2014: Vancouver, British Columbia, Canada; May 29, 2014.

Chou AY. When Being Female is Disadvantageous: The Sex Basis of 2 Specific Cardiac Conditions. UBC Cardiology Grand Rounds: Vancouver, British Columbia, Canada; February 27, 2014.

Chou AY. Surgical Procedures for Congenital Heart Disease. UBC Cardiology Academic Half-Day Teaching: Vancouver, British Columbia, Canada; November 21, 2013.

Wood DA, Poulter R, Chou AY, Boone RB, Owens C, Starovoytov A, Lim I, Bogale N, Lempereur M, Shiekh I, Buller C, Humphries K, Mancini GBJ, Cairns J, Wong GC. Stability of Non Culprit Vessel Fractional Flow Reserve in Patients with ST-Segment Elevation Myocardial Infarction [Poster]. Canadian Cardiovascular Congress 2013: Montreal, Quebec, Canada; October 17-20, 2013.

Chan S, Wong GC, Chou AY, Alipour S, McKinney J, Starovoytov A, Skutezky T, Wong AW, Ketheeswaranathan, Largy W, Taylor CM, Ramanathan K. Diagnostic Value of Lead aVR from 12-lead Electrocardiogram in Predicting Culprit Lesions in Anterior and Inferior ST-Elevation Myocardial Infarction [Poster]. Canadian Cardiovascular Congress 2013: Montreal, Quebec, Canada; October 17-20, 2013.

Chou AY. Marfan Syndrome and Heritable Thoracic Aortic Disorders. Pacific Adult Congenital Heart Clinic Rounds: Vancouver, British Columbia, Canada; October 9, 2013.

Chou AY. The Aging Fontan Circuit. Pacific Adult Congenital Heart Clinic Rounds: Vancouver, British Columbia, Canada; October 2, 2013.

Chou AY, Wong GC, Gao M, Lau B, Ramanathan K. Different ST-Segment Recovery Measures on ECGs Before and After Percutaneous Coronary Intervention Predict In-Hospital Adverse Outcomes in a STEMI Population [Poster]. UBC Cardiac Sciences Research Day 2013: Vancouver, British Columbia, Canada; June 5, 2013.

Chou AY, Wong GC, Gao M, Lau B, Ramanathan K. Different ST-Segment Recovery Measures on ECGs Before and After Percutaneous Coronary Intervention Predict In-Hospital Adverse Outcomes in a STEMI Population [Poster]. American College of Cardiology Annual Scientific Session 2013: San Francisco, California, USA; March 9-11, 2013.

Chou AY, Ramanathan K, Gao M, Chan SH, Aymong ED, Imrie J, Orenstein T, Wong GC. ECGs Pre and Early Post Primary PCI: Important Predictor of In-Hospital Adverse Outcomes in STEMI Population [Poster]. Heart + Lung Health FEST 2013: Vancouver, British Columbia, Canada; February 19-23, 2013.

Chou AY. 2011 Appropriate Use Criteria for Echocardiography. UBC Cardiology Echocardiography Rounds: Vancouver, British Columbia, Canada; December 4, 2012.

Chou AY. Approach to Non-Ischemic Cardiomyopathies. UBC Cardiology Academic Half-Day Teaching: Vancouver, British Columbia, Canada; November 29, 2012.

Chou AY, Ramanathan K, Gao M, Chan SH, Aymong ED, Imrie J, Orenstein T, Wong GC. ECGs Pre and Early Post Primary PCI: Important Predictor of In-Hospital Adverse Outcomes in STEMI Population [Oral Abstract]. Canadian Cardiovascular Congress 2012: Toronto, Ontario, Canada; October 27-31, 2012.

Chou AY, Ramanathan KR. ECG ST-Segment Recovery as Predictors of Survival in Patients with ST-Elevation Myocardial Infarction after Primary Percutaneous Coronary Intervention [Oral Abstract]. UBC Internal Medicine Annual Resident Research Day: Vancouver, British Columbia, Canada; May 23, 2012.

Chou AY, Ramanathan KR. ECG ST-Segment Recovery as Predictors of Survival in Patients with ST-Elevation Myocardial Infarction after Primary Percutaneous Coronary Intervention [Oral Abstract]. Rocky Mountain /ACP Internal Medicine Conference: Banff, Alberta, Canada; November 24-27, 2011.

Chou AY, Baldwin C, Dempsey E, MacCallum C. A Vision for Quality Improvement: Increasing the Frequency of Calls to the BC Eye Bank from the CTU Wards [Oral Abstract]. UBC Internal Medicine Annual Resident Day on Quality Improvement: Vancouver, British Columbia, Canada; December 1, 2010.

Brotto LA, Chou AY, Singh T, Woo, JST. Reproductive Health Practices among Indian, East Asian, and Canadian Women: The Role of Acculturation [Poster]. Society of Obstetricians and Gynaecologists Annual Clinical Meeting: Calgary, Alberta, Canada; June 9-12, 2009.

Matsell D, Butt MJ, Chou AY. Study of the role of the IGF Type I receptor in kidney development [Oral Abstract]. BC Research Institute Student Research Competition: Vancouver, British Columbia, Canada; August 24, 2004.

Ongoing Research:

[Manuscript] ECG ST-Segment Recovery as Predictor of Survival in Patients with ST-Elevation Myocardial Infarction after Primary Percutaneous Coronary Intervention.

[Manuscript] Correlation of Cardiac Risk Factors with Incomplete ST-Elevation Recovery and In-Hospital Adverse Outcomes After Primary PCI in a STEMI Population.

[Manuscript] Microvascular Dysfunction in Patients with ST-Elevation Myocardial Infarction after Primary Percutaneous Coronary Intervention: No Sex Disparity.

[Manuscript] A Tetrad for Success: Dr. Helen Taussig, the Blalock-Taussig Shunt, Intracardiac Repair, and Surveillance Recommendations for Adult Patients with Tetralogy of Fallot.

[Recruitment] Screening for Asymptomatic Coronary Artery Disease in High-Risk Patients with Rheumatoid Arthritis and Systemic Lupus Erythematosus.

Affliliated Projects:

Vandegriend R, Wong GC, Fordyce C, Zhang R, Gao M, Taylor CM, Orenstein T, Chou AY, Alipour S, Ramanathan K. Is fibrinolysis still a viable alternative for patients with ST elevation myocardial infarction: results from a mixed-reperfusion model of ST elevation myocardial infarction care? [Poster]. European Society of Cardiology Congress 2014: Barcelona, Spain; August 30-September 3, 2014.

Tsang MYC, Taylor CM, Rajala J, Ong K, Wong GC, Chou AY, Bains PS, Fordyce C, Dorscheid D, Ramanathan K. The Present Practice of Blood Transfusion in Coronary Care Units: A Registry Study [Poster]. American College of Cardiology Annual Scientific Session 2013: San Francisco, California, USA; March 9-11, 2013.