Introduction

The primary cause of death in the world is cardiovascular disease (CVD), which is responsible for 17.5 million deaths per year. In many developed countries, coronary heart disease mortality is declining, but in developing and transitional countries, it is increasing, partly as a result of increasing ageing, urbanization, and lifestyle changes.1

Acute coronary syndrome (ACS) is a concept that describes a sudden decrease in coronary blood flow, resulting from an acute ischemic insult to the myocardium. The ECG results will help to identify patients into two main divisions, with significant diagnostic and therapeutic implications2. ACS with ST-segment elevation normally describes an acute complete coronary occlusion and presents with acute chest pain and recurrent elevation of > 1 mm ST-segment in at least two anatomically contiguous leads. This condition is referred to as acute ST-segment elevation myocardial infarction (STEMI). Immediate reperfusion with primary angioplasty or fibrinolytic therapy is the mainstay of treatment in these patients.3 Although biomarkers are useful for confirmatory and prognostic purposes, they are not mandatory and should not interrupt care when diagnosing STEMI.

Patients with acute chest pain but no recurrent elevation of the ST-segment are referred to as acute non-ST-segment elevation ACS (NSTE-ACS). The ECG may be normal or there may be intermittent elevation of the ST-segment, persistent or transient depression of the ST-segment, inversion of T waves, flat T waves, or pseudonormalization of T waves.

In order to select an effective management approach, physicians may need to stratify patients according to their risk status and according to the original risk evaluation. Serial ECGs and cardiac biomarkers are included in the initial risk assessment.4 The percutaneous coronary intervention synergy (SYNTAX) score is a systematic method of angiographic scoring.5 It directs the decision-making process between surgery for coronary artery bypass graft (CABG) and percutaneous coronary intervention (PCI).

This calculator takes into consideration the dominance of coronary circulation, total occlusion, trifurcation, calcification, tortuosity of a particular lesion, length of the lesion, and the thrombus content of the lesion.

There are few published studies on the clinical profile of coronary artery disease (CAD) in patients with ACS and its angiographic severity. The purpose of this research, therefore, was to correlate the clinical profile and angiographic significance of CAD in patients with ACS.

Results

STUDY DESIGN: OBSERVATIONAL CROSS SECTIONAL STUDY

The individuals who participated in this study belonged to a single group. The group consisted of individuals belonging to STEMI and NSTEMI.

A total of 209 patients were included in the final analysis.

Among the 209 patients who were included in the study, it was found out that 82.3% (172 participants) were male and 17.7% (37 participants) were female.

Among the 209 ACS patients who were studied, 59 patients had normal left ventricular systolic function. About 47 patients had adequate left ventricular systolic function. Predominantly, patients presenting with ACS had mild left ventricular systolic dysfunction. In this population, 71 patients had mild left ventricular systolic dysfunction, and 30 patients had moderate left ventricular systolic dysfunction. Only 2 patients in our study had severe left ventricular systolic dysfunction.

In this study population, there were 141 patients who were nonsmokers and 68 patients who were smokers. More than 13 patients were smokers for more than 20 years.

In this study population, 137 patients were nonalcoholics and 53 patients had history of alcohol abuse. Four patients had alcohol abuse for more than 20 years.

In this study population, 121 patients were diabetics. This data makes type 2 diabetes mellitus the most common risk factor in this study population. Predominantly, these patients were diabetics for less than 5 years.

In this study population, 93 patients were hypertensives. Predominantly, patients were hypertensives for less than 5 years.

About 27 patients were dyslipidemic in our study.

The most common age group of disease occurrence in our study was between the ages of 30 to 60 years. A total of 146 patients belonged to this group. More than 50 patients belonged to the age group of more than 60 years.

In our study, a striking predominance of anterior wall STEMI was noticed. The second most common type of acute coronary event was inferior wall STEMI and ACS-UA.

The most common type of acute coronary event, according to the broad classification was the STEMI variant, with 134 patients suffering from this ailment.

SYNTAX score 1 was found to be higher in patients presenting with lateral wall MI.

As our data had a non-normal distribution, we applied a nonparametric test (Kruskal–Wallis) to the data. In the correlation between the type of ACS and angiographic severity (SYNTAX score 1), the median value in this study for patients with STEMI was 11.500 and NSTEMI was 10.500. This value was found to be higher in the STEMI group. However, this did not correlate statistically.

As our data had a non-normal distribution, we applied a nonparametric test (Kruskal–Wallis ) to the data. In the correlation between duration of smoking and SYNTAX score 1, there was an increase in median value with increase in duration of smoking.

As our data had a non-normal distribution, we applied a nonparametric test (Kruskal–Wallis) to the data. In the correlation between duration of alcohol abuse and angiographic severity of CAD (SYNTAX score), we noticed an increase in median value with increase in duration of alcohol use. The maximum median values were found in the duration time frame of 10 to 20 years. This was also statistically significant.

As our data had a non-normal distribution, we applied a nonparametric test (Kruskal–Wallis) to the data. In the correlation between duration of systemic hypertension and angiographic severity by SYNTAX score 1, we observed an increase in the median SYNTAX score as the duration of systemic hypertension progressed, with maximum median values in the time frame of 5 to 10 years. This was also statistically significant.

As our data had a non-normal distribution, we applied a nonparametric test (Kruskal–Wallis) to the data. In the correlation between duration of diabetes and angiographic severity by SYNTAX score 1, we observed an increase in the median SYNTAX score as the duration of diabetes progressed, with maximum median values in the time frame of 10 to 20 years.

As our data had a non-normal distribution, we applied a nonparametric test (Kruskal–Wallis) to the data. In the correlation between Killip classification and angiographic severity by SYNTAX score 1, we observed an increase in the median SYNTAX score as the Killip class progressed, with maximum median values in Killip-3 (pulmonary edema). This was also statistically significant.

As our data had a non-normal distribution, we applied a nonparametric test (Kruskal–Wallis) to the data. In the correlation between EF and angiographic severity by SYNTAX score 1, we noticed maximum median values in patients with mild LVEF (EF 40–50%).

Subgroup Analysis in Female Study Population

We also did a subgroup analysis in the female study population which included 37 patients.

A study across the number and the duration of diabetes mellitus among the female population, again, proved that the trend with respect to the number of years the participant suffered from it were less than 5 years mattered. A total of 13 patients had diabetes for less than 5 years.

Here again, 14 patients out of 37 patients were hypertensives for less than 5 years.

UA, in contrast, was the most common acute coronary event.

But, collectively 21 patients presented to us with STEMI, making this the most common broader classified acute coronary event.

We noticed an increase in the SYNTAX score 1 with respect to increase in the duration of diabetes, with the maximum syntax score observed close to 10 to 20 years of the comorbidity. But this was not statistically significant.

The above dictum was also noticed in the female population, with the maximum SYNTAX score being observed over the duration of hypertension (5–10 years), and only three patients in the category, although not statistically significant.

Discussion

Among the patient profile that were collected, clear trends regarding the demographic profile of the presenting population could be established. This demographic profile could also be correlated with the vessel burden, using SYNTAX score 1, where majority of it had statistical significance. We also noticed an increase in the severity of the CAD with increase in duration of the risk factor.

Age and Sex

In this study, 82.3% of the patients were males and 17.7% were females (Table 1). This exhibits a striking male predominance in acute coronary events. We also observed in this study which covered all age groups, not restricting ourselves to a particular set, that most of the patients fell under the age group of 30 to 60 years. Comparing it with the published literature, this was confirmed.

Prajapathi et al did a single center, observational study in novel risk factors and angiographic profile in patients presenting with ACS. They had found that males presented with ACS 24 times more than females in the age group under 40 years and 8 times more than females in the age group more than 40 years. They had also confirmed maximum number of cases presented in the age group of 30 to 60 years. Adding to this, the most common type and subvariant of acute coronary event was anterior wall MI (AWMI).7

Echocardiographic Analysis

In this study, 34% of patients had mild left ventricular systolic dysfunction, followed by normal left ventricular systolic function (28.2%) (Table 2). This was strikingly confirmed by literature worldwide.

In a prospective cohort study done by Brezinov et al in Israel, where a total of 8983 patients who were diagnosed with ACS were admitted (2000–2010) in various critical care units across the country. Among the patients enrolled, 4470 patients had mild-to-moderate left ventricular systolic dysfunction and 3659 patients had preserved LVEF. Less than 10% of patients had severe left ventricular dysfunction.8

Smoking and Alcoholism

It is clear and evident that smoking and alcohol abuse is an important risk factor for CAD and even more important in deciding the mortality risk and the vessel burden. In our study, although, the nonsmoker population was about 67.5%. The maximum number of smokers in this study had practiced the habit for 5 to 10 years (Table 3). In contrast to some journals published, this was not the most common risk factor in this study pertaining to this geographical area.

A study done in Sweden by Bjork et al comprised 93,416 patients who presented with acute MI (AMI). These patients were collected from the Register of Information and Knowledge about Swedish Heart Intensive Care Admissions. In this observational entry, 38% patients had STEMI and 62% patients had NSTEMI. Among smokers, 31% patients presented with STEMI and 22.9% presented with NSTEMI. In this article, among men with STEMI, 58% of the youngest, that is, less than 50 years were smokers, whereas in men with NSTEMI, 47% of them were smokers. In contrast to this, among young women presenting with STEMI, 67% of them were smokers9

Interestingly, smoker's paradox was recorded by Katayama et al in a study of 528 patients who were admitted with diagnosis of AMI; 44% of the case load were smokers. But the paradox was that the 6-month mortality was lower in the smokers than the non-smokers. The earlier ST resolution was also higher in smokers. Most of the smokers in this study were males10

In our study, 65.5% were nonalcoholics (Table 4). Most of the patients were exposed to alcohol/had the habit of consuming alcohol occasionally. Binge drinking pattern was also noticed among the study population. The data on heavy binge prior to the MI is not available. Comparing this to world literature, a case control study was performed across 52 countries by Leong et al. The INTERHEART study was done with 12,461 individuals who presented with AMI. This study provided valuable information on alcohol use as a risk factor and its demographic characteristics. For instance, in women less than 45 years, it was found it had a protective effect. They also assessed whether a heavy binge preceding the event of ACS has a correlation. The hazard period to binge was defined as alcohol consumption within 24 hours prior to the event. Control period was defined as 48 hours prior to the event during which the binge took place. It was found that heavy binge (> 6 drinks) during hazard period significantly increases risk of MI. The more harmful association of occurrence of MI in those who drank more frequently was also established. Hence binge drinking, especially in older individuals, led to MI. Moderate amount consumption in most populations had a lower risk of MI. This however could not be said for all geographical variables. It was also stipulated that binge drinking could have brought in acute but drastic changes in the lipid profile. It could also result in overt hypertension 20 hours after the binge.11

Type II Diabetes and Systemic Hypertension

These two risk factors are established as direct causative risk factors in MI, increasing cardiovascular burden, and secondary pathological diagnosis. In this study, diabetes was the most common risk factor (53.1%) (Table 5). The bulk of the patients were recently diagnosed or were victims of the condition for less than 5 years. Systemic hypertension was found in about 44.5% of patients. Again, here too, the bulk of the patients were recently diagnosed hypertensives (< 5 years) (Table 6).

Correlating this with the global literature, Isezuo et al achieved a cross-sectional retrospective study of 1468 patients who presented with ACS. This study was done in Madras Medical Mission, Chennai, India. These patients were followed-up for a year after hospitalization. Systemic hypertension, type II diabetes mellitus, and dyslipidemia were found to be top risk factors12 (Table 7).

Correlation between Clinical Profile and Syntax Score

There were some characteristic findings in this study, some of which had statistical significance.

Correlation between the type of event (STEMI/NSTE-ACS) and SYNTAX score 1 was done. It was found that the STEMI variant had a slightly higher median value of 11.500 than the NSTEMI variant, which had a median value of 10.000. But the range of quartiles was much higher in the NSTEMI group (Table 12).

Correlation between the duration of smoking and SYNTAX score 1 was observed. Here, the duration of smoking more than 20 years had the highest median value of 15 (Table 13).

Correlation between the duration of alcohol consumption/exposure was noted. Here, too, as the duration of exposure rose, the median value of SYNTAX score 1 increased. Median value of 16.500 was observed, which was the highest and found in the duration of 10 to 20 years (Table 14).

As explained earlier, as in any massive literature entry or miniscule study, diabetes mellitus and systemic hypertension are the most important risk factors. In this study, it was noted that a median value of 15.000 was present, and it was highest in patients with a history of diabetes duration of 10 to 20 years. This was also found in patients who had systemic hypertension as a risk factor. Here, too, a median value of 15.000 was observed. The median value of SYNTAX score 1 was highest in patients with history of systemic hypertension for 10 to 20 years. So, the duration of risk factor implied an increase in the SYNTAX score (Table 15).

Only 24 patients were diabetics. But in the diabetic population, high SYNTAX score was noted in 10 patients, whereas 14 others had low and mid scores. This implies that diabetics have a more severe angiographic burden (Table 16). As predicted, high SYNTAX score also meant high mortality risk.13

Killip III/IV had the maximum median values of 18.750 and 17.500, respectively. This depicted increase in SYNTAX score as the Killip presentation increased.17

Looking at global literature, a study was done by Choudhary et al in SMS Hospital (Jaipur), where SYNTAX score 1 was calculated for 90 patients presenting with STEMI and for those who were planned for PCI. SYNTAX score was broadly classified into low, mid, and high. Low being < 15, mid being 16 to 22 and high being > 23. In this study, the mean age was 54.2 ± 11.6. There was male predominance as stated before. In this study, tobacco usage was the major risk factor, followed closely by systemic hypertension and diabetes mellitus. A total of 49 patients were smokers, of which 17 fell under low and mid, and 15 had high SYNTAX score. A total of 39 patients were hypertensives. 15 had low score, 12 had mid score, and 12 other patients had high scores.

In our study, AWMI was the most common, and lateral wall MI was the least common, with 71 patients suffering from the former and 2 patients from the latter (Table 11).

A study done by Tanveer et al, Sri Jayadeva Institute of Cardiovascular Science and Research, Bangalore, confirmed this data. This registry studied the correlation between SYNTAX score in STEMI and high-sensitivity C-reactive protein (CRP). This study also took into account the clinical profile which makes this study unique. Males were more commonly affected. Mean age was 54.37 ± 11.73. Dyslipidemia was the most common risk factor in this study, with 158 patients having deranged lipid profile, which makes this study unique as either smoking or diabetes have been recorded in every other study. In this, patients were divided into the following three groups based on SYNTAX score: low (0–22), intermediate (23–31) and high (> 33). Most patients belonged to the low category.14

In another study done by Dursun et al, 348 patients with MI were identified. A total of 161 were diagnosed to have STEMI and the rest NSTEMI. NSTEMI patients were found to be more commonly smokers, diabetics, and had a strong prior ischemic heart disease. In this study, SYNTAX score was found to be higher in the STEMI group15.

Finally, the most important risk factor, deranged lipid profile, which was not the most common risk factor in this population. Only 27 patients were found to have dyslipidemia (Table 7). In this study, we have correlated LDL and non-HDL with SYNTAX score 1, hoping for a significance, but there was none. A study done by Kurmus et al in Turkey did a retrospective study which involved 574 patients requiring coronary angiography, but published no statistical correlation between LDL/non-HDL and SYNTAX score 1.16 In another study published by Li et al, from Wuhan University, 1867 patients were evaluated and analyzed retrospectively. SYNTAX score 1 in this population also were divided into three groups—mild (< 8), moderate (8–15) and severe (> 15). Non-HDL in this study was found to be higher in the mild group.17

Conclusion

Our study showed a male predominance in the study population that presented. Type II diabetes mellitus and systemic hypertension were the two most common risk factors. The occurrence of ACS in patients who had duration of the above said two risk factors for less than 5 years was also noticed to be elevated, indicating a need for vigilant care in newly diagnosed diabetics and hypertensives. Majority of the ACS occurred in the age group of 30 to 60 years, which is also deeply disturbing, as the age where the expectation of ACS has gone down in the recent past, and it is predicted to go down further in the future due to various lifestyle comorbidities. STEMI was the most common cardiac event. Among STEMI, AWMI was the most common.

SYNTAX score 1 was higher in patients with lateral wall myocardial infarction (LWMI) and was mildly significant. As the duration of alcohol use increased, the SYNTAX score 1 also increased, and this was statistically significant. The same holds good for systemic hypertension, and it was statistically significant. Another statistically significant observation was that the SYNTAX score 1 also increased, with clinical signs of left ventricular failure, as classified by Killip score.

Even though not statistically significant, the SYNTAX score 1 also increased with the duration of diabetes mellitus. SYNTAX score 1 was noticed to be maximal with LWMI.

Our study gives insight into the trends noticed in the ACS patient population that we have received in the recent past. The shocking occurrence of ACS in young and the risk factors that can be directly attributed to the pathology also need to be taken into consideration.