Association between ST-segment depression and angiographic severity of coronary artery disease in patients with non-ST-segment elevation MI

Abstract

Background: NSTEMI patients account for a significant proportion of patients hospitalized in coronary care units. The earliest and most straightforward objective data for NSTEACS risk classification is provided by a 12-lead electrocardiogram (ECG). We made an effort to find out the association between the magnitude of ST-segment depression and angiographic severity in NSTEMI patients.

Methods: This cross-sectional study was conducted in the Department of Cardiology of Dhaka Medical College & Hospital, Dhaka, for 12 months following ethical approval. A total of 120 patients with NSTEMI who were admitted during the study period and underwent a coronary angiogram were included in the study, provided they met the inclusion and exclusion criteria after taking informed written consent. According to the degree of ST-segment depression, patients were divided into three groups: Group I (no or less than 1 mm ST-segment depression), Group II (1-2 mm ST-segment depression), and Group III (> 2 mm ST-segment depression). Angiographic severity of coronary artery disease was assessed by 3 scoring systems - Vessel score, Gensini score, and Friesinger index. According to the Gensini score, the severity of coronary artery disease was assessed and categorized into two groups: Normal or mild CAD (Gensini score ≤ 36), Significant CAD (Gensini score >36). According to the Friesinger index, the severity of coronary artery disease was assessed and categorized into two groups: significant CAD (Friesinger index ≥5) and insignificant CAD (Friesinger index <5). The magnitude of ST-segment depression was compared with the angiographic severity of CAD. All statistical analysis was performed using the Statistical Package for the Social Sciences (SPSS) program, version 21 for Windows.

Results: The mean age of the study population was 52.7±10.1 years. Male patients were predominant. Male-female ratio was 4.45:1. Smoking (58.3%) was the most prevalent risk factor, followed by dyslipidaemia (54.2%), hypertension (46.7%) & positive family history of premature CAD (40.8%). Mean Vessel score of NSTEMI patients was 1.3±.0.8, 2.3±0.9, and 2.4±0.8 in Group I, Group II, and Group III, respectively. Mean Gensini score was 29.0±.30.4, 55.4±22.9, and 85.7±39.7 in Group I, Group II, and Group III, respectively. Mean Friesinger index was 5.3±.3.2, 9.7±3.5, and 10.7±3.17 in Group I, Group II, and Group III, respectively. The differences among the groups were statistically significant. The cumulative sum of ST segment depression showed a positive correlation with Vessel score (r=0.64; p< 0.001), Gensini score (r=0.72; p< 0.001), and Friesinger index (r=0.66; p< 0.001).

Conclusion: This study demonstrated a strong correlation between the degree of coronary artery disease and the amplitude of ST-segment depression. The severity of coronary artery disease was also found to be substantially linked with the cumulative amount of ST-segment depression. This study also demonstrated that the primary predictors of severe CAD include smoking, ST-segment depression, diabetes mellitus, and aging. Adverse cardiac events may be significantly reduced in these people with prompt, appropriate medical care and intervention.