Pattern of coronary arterial lesions amongst Saudi Arabians: a cross-sectional coronary fluoroscopic angiography study

Introduction Coronary artery disease (CAD) is a major cardiovascular disease (CVD) that affects a large population globally. This study aimed at determining coronary arterial lesions (CAL), particularly in terms of age, gender, coronary artery/arteries involved, number of lesions, and dominant coronary artery in the Kingdom of Saudi Arabia (KSA). Methods A cross-sectional study was conducted at the King Khalid Hospital and Prince Sultan Centre for Health Care in Al-Kharj between January 2017 and March 2018. The patients with CAD lesion/s, fulfilling the inclusion criteria, were recruited from the cardiovascular medicine unit. Demographic information and the location and extent of their CAD lesions were extracted and documented in electronic case report form (eCRF). SPSS 22.0 was used for statistical analysis, and p value ≤ 0.05 was considered as significant. Results Of the 262 patients, male and female preponderance was 74.8% and 25.2%, respectively. The majority of the patients were adults above the age of 50 (72%). About half of all patients were active smokers (53%). Diabetes, hypertension, and hyperlipidaemia were recorded in 63%, 53.7% and 25% respectively. The incidence of cardiovascular lesions was documented after coronary angiography; left circumflex artery lesions had the highest incidence (85.3%), followed by left anterior descending artery lesions (82.4%) and right circumflex artery lesions (74.3%). Left main coronary artery lesions had the lowest incidence (10.3%). Most patients (59.6%) had three concomitant lesions, whereas a minority of patients had two (22.8%) and one lesion (17.7%). Conclusion The pattern of CALs is different among the Saudi population as compared to other countries.


Introduction
Coronary artery disease (CAD) is a major cardiovascular disease (CVD) that affects approximately 422.7 million people globally [1,2]. In the United States alone, 15.5 million individuals above 20 years of age suffer from coronary heart disease (CHD) [3]. Globally, 17.5 million people died of cardiovascular disease (CVD) in 2012; 7.4 million deaths were contributed to CAD [4]. Prevalence of CAD in the Kingdom of Saudi Arabia (KSA) has been reported to be 6.4% of men and 4.4% of women [5]. According to the statistics of World Health Organization (WHO) 2016, about 37% of deaths were attributed to CVD [6], indicating KSA bears a significant burden of CAD, like other countries in the world. Increasing age is a well-established risk factor for CAD. For instance, incidence of CHD is doubled and tripled for men and women, respectively, at 65-94 years as compared to that at 35-64 years [3]. The reason for this increased risk of CAD can be attributed to the progressive decline of physiological functions, which leads to health problems. Similarly, increasing age affects the cardiovascular system in terms of pathological alterations (e.g. hypertrophy, left ventricular dysfunction, arterial stiffness, impaired endothelial function, etc.), contributing to atherosclerosis, hypertension, and myocardial infarction (MI) [7]. As incidence of hypertension increases with advancing age, it further increases the risk of CAD.
Gender differences at the same age exist for the incidence of CAD.
Men are at higher risk of developing CAD as compared to women of the same age [8]. Lifetime risk of developing CHD for men and women aged 40 years is 49% and 32% respectively, while it is 35% for men and 24% for women at age 70 years [3]. Similarly, women lag behind men by 10-20 years in terms of occurrence of coronary events [3].
There might be various reasons for these gender differences in the development of CAD. For example, women are likely to have non-obstructive CAD and take longer to obtain medical advice as compared to men [9]. In KSA, studies are lacking on the different lesions of CAD. In this study, we aimed at determining coronary arterial lesions (CAL), particularly in terms of age, gender, coronary artery/arteries involved, number of lesions, and dominant coronary artery in KSA. This study is a valuable addition to the literature on arterial lesions of CAD in KSA.

Methods
This topic was chosen for in-depth research to fulfill the aim of determining the prevalence and pattern of coronary artery disease (CAD) lesions amongst cardiovascular patients at a tertiary healthcare institution in the Kingdom of Saudi Arabia (KSA). Demographic variables, such as age and gender, were analyzed to identify potential associations among variables and prevalence of CAD. A comprehensive search of the literature was undertaken on medical databases (e.g. PubMed, Embase and Medline) with the following search terms -KSA, Saudi, coronary, ischemic, lesion, artery. Boolean operators, such as AND and OR, were utilized to generate productive and focused results. The search produced studies that explored the prevalence of CAD in KSA. However, to the best of the authors´ knowledge, no study has been scoped to determine the prevalence of specific CAD lesions amongst the KSA population. Hence, a cross-sectional study set out to delineate this phenomenon was

Results
The aim of this study was to delineate the lesions of coronary artery disease (CAD) according to age and gender amongst a patient pool in the Kingdom of Saudi Arabia (KSA). Of the 262 patients recruited for this study, there was an overall male preponderance (74.8%) compared to females (25.2%). The majority of these patients were adults above the age of 50 (72%). About half of all patients were active smokers (53%). In regard to comorbid disease, 25% of patients had documented hyperlipidaemia, 53.7% had chronic hypertension, and 63% were chronic diabetics. The incidence of cardiovascular lesions was documented after coronary angiography -left circumflex artery lesions had the highest incidence (85.  Table 1. Associations between the lesions of coronary artery disease and demographic indices were observed. For example, a statistically significant (p = 0.001) association between the presence of a left circumflex artery lesion and age was found. Specifically, as age increased, there was a higher likelihood of a left circumflex artery lesion, as delineated in Table 2. Similarly, there was a statistically significant (p = 0.026) association between the presence of a right coronary artery lesion and age. However, these associations should be interpreted with caution; the sample size of patients in specific age categories was between 0 and 5 in more than 20% of all age categories. A larger sample size would have lent more credibility to the associations observed. There were no statistically significant associations observed between age and the presence of left main coronary artery or left anterior descending artery lesions. There was also no statistically significant association between age and the number of affected vessels. Age was not associated with the type of management (coronary artery bypass grafting, endovascular stenting, or conservative treatment). The distribution of management strategies is reflected in Figure 1. No statistically significant associations were observed between gender and CAD lesions, as reflected in Table 3. There was also no statistically significant association observed between the dominant coronary artery and gender. The prevalence of the dominant coronary artery amongst the patient pool is reflected in Figure 2.' The present study revealed significant association between the age of the patient and the involvement of LCX and RCA. In Saudi Arabia, coronary arterial lesions (CALs) are significantly higher in the older population compared to younger people. However, this finding cannot be generalized, as the sample size of patients in specific age categories was between 0 and 5 in more than 20% of all age categories. Therefore, a larger sample size would lend credibility to the associations observed. In contrast, Tsai et al. [12] conducted a study in Taiwan, including 245 patients below 40 years of age suffering from acute coronary syndrome (ACS) and occlusive CAD.

Discussion
They reported maximum lesions in LAD, followed by LCX and RCA.
Again, this study from Taiwan differed in terms of arterial lesions in CAD. Similarly, frequency of involvement of RCA lesion significantly differs with age. The present study revealed diabetes is the most common risk factor of CAD among the Saudi population, as 07 million people are diabetic and about 03 million people are pre-diabetic in Saudi Arabia [13]. Frequency of risk factors of CAD varies with geographical areas and advancing age. Nadeem et al. [14] conducted a study in Pakistan including 109 patients below the age of 45. They reported cigarette smoking (46%) as the most common risk factor of CAD, followed by family history (43%), high blood pressure (37%), dyslipidemia (33%), and diabetes mellitus (18%). These results indicate a huge difference in risk factors among the Pakistani and Saudi populations. This difference may be caused by age, below 45 years. In this regard, Abbot et al. [15] demonstrated that risk factors of CAD change with advancing age.

Conclusion
This is the first comprehensive study on CALs from Saudi Arabia that reports the frequency of CALs in CAD among the Saudi population. It has revealed an important finding that the pattern of CALs is different among the Saudi population as compared to other countries. This difference may affect preventive and management strategies in KSA.
Therefore, further evaluation through prospective studies on a large scale is necessary to find reasons for the different pattern of CALs in KSA.

What is known about this topic
• Coronary artery disease is a major cardiovascular disease that affects approximately 422.7 million people globally; • Prevalence of coronary artery disease in the Kingdom of Saudi Arabia has been reported to be 6.4% of men and 4.4% of women; • In Saudi Arabia, approximately 37% of deaths are attributed to cardiovascular disease.

What this study adds
• This is the first comprehensive study on coronary artery lesions from Saudi Arabia that reports the frequency of coronary artery lesions in coronary artery disease among the Saudi population; • Left circumflex artery is the most frequently involved coronary artery lesion involved in coronary artery disease in Saudi Arabia; • The pattern of coronary artery lesion is different among the Saudi population as compared to other countries.      Life> 0 (0%) 0 (0%) 2 (0.74%) 1 (0.37%) 2 (0.74%) Results are based on nonempty rows and columns in each innermost table. *. The Chi-square statistic is significant at the 0.05 level. a. More than 20% of cells in this subtable have expected cell counts less than 5. Chi-square results may be invalid. b. The minimum expected cell count in this subtable is less than one. Chi-square results may be invalid.