A Study on Angiographic profile of Acute Coronary Syndrome in Smokers

Background: Coronary artery disease is a devastating disease precisely because an otherwise healthy person in the prime of life may die or become disabled without warning. The objectives of the study were to study the clinical profile, risk factors prevalence, angiographic distribution and severity of coronary artery stenosis in acute coronary syndrome (ACS) patients admitted in Cardiology Department of Cardiology Katuri Medical College & Hospital, Guntur. Subjects andMethods: A total of 208 patients of ACS were analyzed for various risk factors, angiographic patterns and severity of coronary artery disease in smokers vs non-smokers at Katuri Medical College, Andhra Pradesh. Results: Study group consisted of 208 subjects, of which 108(51.9%) subjects were smokers including all forms of tobacco use and 100 (48.1 Out of 108 study subjects in the smokers group, family history of CAD was present in 21 (19.4%) subjects. Killip class is not applicable to 13 (12%) study groups as they presented with Unstable Angina with ECG changes. Killip class 1 was most common presentation (67.6%) in smokers. 28 patients (25.9%) had LV dysfunction with EF < 50% by echocardiography. 80 patients (74.1%) had normal LV function. The mean EF was 55.56+/-10.16%. The median EF was 56.5%. LAD was type 3 in 100 (92.6%) patients and type 4 in 8 (7.4%) patients out of 108 study subjects. LAD type 3 was statistically significant with P value < 0.05 when compared with LAD type 4. No statistically significant difference was seen with respect to the Normal coronary arteries as CAG diagnosis between smokers and non-smokers (6.7% versus 8%, p>0.1, Not significant). Conclusion: Smokers were predominantly male and around 3 years younger than non-smokers. Diabetes mellitus and hypertension were less common among smokers and single-vessel disease was the more common angiographic finding for smokers as compared to 3-vessel disease for non-smokers. ST-segment elevation myocardial infarction in smokers despite younger age and the low atherosclerotic risk profile, in our region, emphasize the need for nicotine addiction management and smoking cessation campaigns at large and for pre-discharge counseling.


Introduction
Cardiovascular disease (CVD) is the leading cause of death globally. [1] Cigarette smoking is a major modifiable risk factor for CVD, including coronary artery disease (CAD), stroke, peripheral vascular disease, and congestive heart failure. [2,3] The relationship between cigarette smoking and many established risk factors for CVD have been studied. Cigarette smoking is associated with higher levels of serum cholesterol, coronary vasomotor reactivity, platelet aggregation, and a prothrombotic state. [4][5][6][7] By the year 2030, cigarette smoking will contribute to 10 million deaths per year, 70% of them in lowand middle-income countries. [8] There are multiple and interacting determinants that affect smoking. [9] These are physiological factors (nicotine addiction), personal characteristics (demographics, personality, education, and information), cognition and skills, environment (social, cultural, economic and political) and other concomitant habits (drinking alcohol, coffee etc). [10] Cigarette smoking is generally known as an important risk factor for pathogenesis of coronary artery disease (CAD), as well as prognosis. [1][2][3][4][5][6][7][8] Smoking cessation is recommended by international guidelines as one of crucial measurements for secondary prevention regardless of revascularization. [9][10][11][12] Angiographic assessment is a vital step in the planning management and treatment for patients with cardiovascular diseases. Local data regarding clinical and angiographic characteristics of smoker patients is lacking. This study was planned to assess the differences in the clinical characteristics, angio-graphic characteristics, and in-hospital outcomes of smokers and non-smokers after primary percutaneous coronary intervention (PCI) at a tertiary care hospital.
Therefore our aim of our study was to determine the angiographic profile in acute coronary syndrome of smokers. The various baseline characteristics studied include, age and sex of the patients, presentation of the Acute coronary syndrome (Unstable angina with ECG changes versus acute myocardial infarction (acute STEMI+acute NSTEMI)

2D Echocardiography:
All the echocardiograms were done on a IE 133 phillips echocardiography machine. The echocardiography parameters evaluated included: • Ejection fraction as impaired LV function (EF<50% or normal (EF>/50%). • Coronary angiograms were performed with SIEMENS CATH LAB on all the patients within 5 to 7 days after ACS /Primary PTCA done in the case of eligible patients. Informed consent was taken from all the patients.
• Coronary angiograms were compared between smokers and non smokers with respect to Normal coronary arteries, Single Vessel disease (SVD), Double Vessel disease (DVD), Triple Vessel disease (TVD), Left main coronary artery (LMCA) involvement, Proximal LAD involvement. • Coronary angiograms were analyzed for the following characteristics in the smokers group.

Number of vessels involved
Severity of the lesion a. Based on the percentage diameter stenosis of the involved artery compared to the normal reference segment.
b. Lesions are classified as severe if 70% or more diameter stenosis is observed in the LAD, LCX, RCA and more than or equal to 50% diameter stenosis in the LMCA.

Location of the lesion in the involved artery
• LAD: ostial, proximal, middle or distal/ its major branch • LCX: ostial, proximal, middle or distal / its major branch • RCA: ostial, proximal, middle or distal / its major branch Length of the lesion: measured shoulder to shoulder in an nonfore shortened view • Discrete: lesion length less than 10 mm • Tubular: lesion length 10 to 20 mm • Diffuse: lesion length of at least 20 mm Present study defined, SVD >/= 40% diameter stenosis in one epicardial coronary artery (diameter > 2.25mm) with respect to reference vessel diameter.
DVD defined as >/= 40% diameter stenosis in two epicardial coronary arteries (diameter>2.25mm) with respect to reference vessel diameter.
LMCA involvement defined with > or equal to 30% diameter narrowing.
Angiographic profile was analyzed with respect to each of the baseline characters described above in the smokers group.

Statistical analysis
Statistical Analysis was done using SPSS software. Mean, median, standard deviation and Chi Squares were calculated wherever applicable. P value of p<0.05 was considered statistically significant. Statistically, there was no significance difference between males and females with respect to number of vessels involved.
Double vessel disease, even though not statistically significant, was more commonly encountered in smokers when compared to non-smokers (26.8% versus 18%,p>0.1,Not significant).
Triple vessel disease was equally encountered in both smokers and non-smokers (21.1% versus 23%,p>0.1,Not significant)

LAD (Left anterior descending artery); Absent (mid and distal LAD stenosis+Normal LAD); NS (Non significant)
Out of 108 study subjects in the smokers group, proximal LAD stenosis was present in 32(29.6%) study subjects. Out of 100 study subjects in the non smokers group, proximal LAD stenosis was present in 25(25%) subjects.

Baseline characters and angiographic profile in smokers Age Vs Angiographic profile in smokers
Normal coronaries and SVD, DVD, TVD vs Age Chi square=7.96, P value = 0.05 significant Out of 108 study subjects with normal coronaries, 7 (100%) patients were less than 50yrs age group. Out of 49 patients with SVD, 20 (40.8%) patients were up to the age of 50 years and remaining 29 (59.1%) were more than 50 years. Out of 26 patients with DVD, 11 (42.3%) were upto the age of 50 years and remaining 15 (57.7%) were more than 50 years. Out of 19 patients with TVD, 6 (31.5%) patients were up to the age group of 50 years and remaining13 (68.5%) were more 50 years .Out of 7 patients with LMCA involvement,6 (85.7%) patients were more than 50 years and remaining 1 (14.3%) patient was less than 50 years.
A significantly higher proportion of patients (100%) up to 50 years of age have normal coronaries (No vessels involved). A Statistically significant higher proportion of patients (85.7%) with age more than 50 yrs have LMCA involvement (Chi square -6.96, P = 0.005). Among study subjects with coronary artery involvement seen, there was a statistically significant difference between hypertensives and Non hypertensives with respect to TVD / LMCA involvement.
Combined form (64.8%) with p value <0.001, was the most common form of tobacco use in smokers. Heavy smoking (2.9%) was least common form of tobacco tobacco use.

Discussion
In the present study, the majority of patients in the smoking group were males (74.1%) when compared to females but majority of patients in the non-smoking group were females (61%). The mean age of the patients in the smoking group was 53.52years and in the non-smokers, mean age was 59.48years.
In the present study, smoking reduced the age at which the first coronary event occurred by approximately seven years.
Majority of the study subjects reached ICCU with acute myocardial infarction as acute coronary event but Unstable angina with ECG changes was often encountered in the non smokers group. The smokers had a greater prevalence of infarction and less unstable angina, probably related to younger age and due to the procoagulant effect of tobacco.
In smokers, anterior wall STEMI (44.1%) was the most common presentation followed by acute inferior wall STEMI (34.3%). [13][14][15] A stronger association was seen between smoking and obesity and a weaker one with Diabetes mellitus. Diabetes mellitus was more common in the non smoker group. Hypertension had no association with smoking.
Smokers had a relatively greater number of associated risk factors than non smokers. The smokers had more obesity than non smokers.
Majority of the patients (74.1%) in the study group had EF >50% with mean EF was 55.56%.
The Combined form of Tobacco (64.8%) use was the most commom in the smokers group and difficulty to measure smoking index in all smoking subjects and heavy smoking (smoking index>/=20 pack years) was less common (3.29%). Present study included patients with current smoking and Ex smoking within 6 monthes of cessation with all forms of smoking. [16][17][18] Majority of the study subjects in smokers had the dominant Right coronary artery and the Rigyt coronary artery was codominant in 2.8%in smokers. Type 3 LAD was seen in majority of the smokers (92.6%).
Single vessel disease was the most common CAG diagnosis followed by Double vessel disease was in both smokers and non-smokers.
Significant LMCA (>/=30%diameter stenosis) involvement was often seen in Diabetic patients as an additional risk factor in smokers. There was no significant difference between males and females with respect to number of vessels involved in study population.
LAD was the artery predominantly involved in smokers .Among the involved coronaries, discrete lesions were predominantly seen when compared to long/diffuse lesions in each of the individual vessels in smokers group compared to non-smokers. There was no statistical difference with respect to proximal LAD involvement (>/= 40%diameter stenosis) between smokers and non-smokers. [19] An analysis between the baseline characteristics and the angiographic profile in smokers was suggestive of the following features: Significant coronary artery involvement (diameter stenosis>/=40% of the reference vessel ) was seen in a higher proportion of patients who were older than 50 years, in a higher proportion of patients who were diabetics, hypertensive & obese patients in addition to the smoking.
The LMCA was involved in majority of patients older than 50years and often seen in Diabetics in all study subjects.
GRACE is a multinational observational registry and compared smokers Vs non-smokers in acute coronary syndrome and based on 19,325 patients aged at least 18 years admitted for acute coronary syndromes.
GRACE study showed that Smokers were more frequently diagnosed with STEMI (46.0%) than former smokers (27.4%) and non-smokers (30.2%) (P<0.001). Smokers were mostly men, were younger than non-smokers across the three acute coronary syndrome groups. [15] In In coronary angiogram, single vessel disease was seen in 42% of patients and multi vessel disease in 37% of patients. Recanalised coronary arteries with no significant flow limiting disease were seen in 21% of patients. Multi vessel disease was seen in patients with diabetes or newly detected diabetics. Multi vessel disease was higher in patients with LV dysfunction (68%) whereas recenalised coronaries after thrombolytic therapy was 9 %. [18][19][20] In comparison with above two studies, present study showed younger age of presentation of acute coronary syndrome in smokers, often seen in males, with mean age of 53.52 years and smokers had more obesity and less diabetes mellitus when compared to non-smokers. Single vessel disease, LAD involvement were seen in a higher percentage of patients in the present study subjects. [20] Limitations 1. More critically ill patients were excluded like ACS patients with cardiogenic shock. 2. Difficulty to quantify the smoking parameters with respect to acute coronary syndrome.

Smokers presented with more Acute infarctions and less
Unstable angina compared with non-smokers (P<0 001). 2. Anterior wall STEMI was the most common acute coronary syndrome among smokers. 3. Single vessel disease wasthe most common CAG diagnosis in both smokers and non-smokers. 4. LMCA involvement was commonly encountered in both smokers and non-smokers who had diabetes mellitus.