Screening for Asymptomatic Coronary Artery Disease via Exercise Stress Testing in Patients With Type 2 Diabetes Mellitus: A Systematic Review and Meta-Analysis

Objectives: This meta-analysis aims to investigate the diagnostic value of exercise stress testing (EST) for asymptomatic coronary artery disease (CAD) among patients with type 2 diabetes mellitus (T2DM) and to ascertain the influence of different variables on the sensitivity and specificity of EST.Background: Asymptomatic CAD occurs in >1 in five diabetes mellitus patients, and it is associated with an increased risk of complications. Methods for screening asymptomatic CAD in T2DM patients are still not unified.Methods: MEDLINE (via Ovid), Embase (via Ovid), Cochrane Library, SCOPUS, PubMed, Ovid, EBSCO ASP, and Web of Science were systematically searched on June 8 and 9, 2021, for diagnostic cohort and case-control studies. We included studies that used EST to screen for CAD in asymptomatic patients with T2DM, and that used coronary angiography to diagnose CAD and had reported the basic diagnostic indicators. The Quality Assessment of Diagnostic Accuracy Studies 2 tool was used to assess study quality. The combined effect sizes were calculated by overall analysis and multiple variable effects were explored by regression analysis and subgroup analysis.Results: Nine groups of data from eight diagnostic cohort studies, totaling 515 participants, were included. Included studies showed a low risk of bias in most items, except for flow and timing. The combined sensitivity and specificity of EST for asymptomatic CAD in patients with T2DM were 55 (48 to 61%) and 66 (61 to 70%), respectively. When non-diagnostic tests were excluded, sensitivity increased to 73 (56 to 88%). The proportion receiving angiography also significantly affected sensitivity. No significant difference was found in the duration of diabetes or other additional risk factors.Conclusions: EST is a tool of moderate sensitivity and specificity to be used for the initial screening of asymptomatic CAD in T2DM. It has the advantage of being non-invasive, relatively inexpensive, easily available in most settings, and has no radiation associated with its use. Additional research with higher quality studies in which tests that are non-diagnostic are included and flow and timing is described clearly, will be important to further our understanding of EST for asymptomatic CAD detection in patients with T2DM.Systematic review registration: PROSPERO CRD42021259555.

Screening for Asymptomatic Coronary Artery Disease in People With Type2 Diabetes Mellitus in a Tertiary Care Center

Cardiovascular disease is the biggest driver of mortality in people with diabetes. Cardiovascular disease and diabetes share the same risk factors, the so-called “common soil” hypothesis. Asians and more specifically Indians are predisposed to cardiovascular disease, that too at an earlier age. The cost of management of cardiovascular disease in India is prohibitive. Thus, screening for asymptomatic coronary artery disease in people with type 2 diabetes and referring them for further evaluation will go a long way in preventing cardiovascular mortality. 560 consenting previously diagnosed people with type 2 diabetes, undergoing treatment for type 2 diabetes at our center, were recruited in the study. We used the risk score model for the assessment of coronary artery disease in asymptomatic patients with type 2 diabetes (1) because it was easy to use, specific for Asian population and validated with coronary computed tomographic angiography in asymptomatic people with type 2 diabetes. Questions regarding smoking, past history of stroke and duration of diabetes were recorded as per the risk score and accordingly the subjects were labelled low, intermediate and high risk. Anthropometric measurements were recorded, lipid profile was measured, neuropathy assessment was done using the DNS score. Results: 48.9%subjects were females,51.1% were males, mean duration of diabetes was 3.5 years, mean HbA1c was 8.5%, mean BMI 26.5kg/m2, mean age was 51.4 years, mean CAD score was 4.1 44.2% of the subjects were in a low risk category, 44.9% were in the intermediate risk category and 10.9% in the high-risk category. The maximum people had intermediate to high risk and were in the age group of 50–60 years (21.3%), followed by 13% in the 60–70 age group. Surprisingly, 12.6% people in the 40-50year age group had an intermediate to high risk score for ASCVD. The high prevalence of intermediate to high risk in relatively younger populations with shorter duration of diabetes (mean duration of diabetes 3.5 years) mandates universal screening for asymptomatic coronary artery disease in all people with type 2 diabetes mellitus. Our study highlights the importance of identifying asymptomatic coronary artery disease using locally relevant risk models and their timely referral to prevent excessive cardiovascular mortality in people with type 2 diabetes mellitus. This would ensure optimum utilization and prioritization of scarce resources in resource crunch situations. Keywords: Screening, asymptomatic CAD, type 2 diabetes mellitus. References: 1. Park G-M, An H, Lee S-W, Cho Y-R, Gil EH, Her SH, et al. Risk Score Model for the Assessment of Coronary Artery Disease in Asymptomatic Patients With Type 2 Diabetes. Medicine [Internet]. 2015 Jan [cited 2020 Oct 14];94(4):e508. Available from: https://journals.lww.com/md-journal/Fulltext/2015/01040/Risk_Score_Model_for_the_Assessment_of_Coronary.44.aspx

Is hypertensive left ventricular hypertrophy a cause of sustained ventricular arrhythmias in humans?

Sudden cardiac death (SCD) is most commonly secondary to sustained ventricular arrhythmias (VAs). This review aimed to evaluate if left ventricular hypertrophy (LVH) secondary to systemic hypertension in humans is an isolated risk factor for ventricular arrhythmogenesis. Animal models of hypertensive LVH have shown changes in ion channel function and distribution, gap junction re-distribution and fibrotic deposition. Clinical data has consistently exhibited an increase in prevalence and complexity of non-sustained VAs on electrocardiographic monitoring. However, there is a dearth of trials suggesting progression to sustained VAs and SCD, with extrapolations being confounded by presence of co-existent asymptomatic coronary artery disease (CAD). Putatively, this lack of data may be due to the presence of more homogenous distribution of pathophysiological changes seen in those with hypertensive LVH versus known pro-arrhythmic conditions such as HCM and myocardial infarction. The overall impression is that sustained VAs in the context of hypertensive LVH are most likely to be precipitated by other causes such as CAD or electrolyte disturbance.