Background
Coronary artery disease (CAD) is a major cause of morbidity and mortality worldwide. CAD is a disease usually found in the old. Nowadays, however, it’s often encountered by young adults. It is estimated that about 4–10 % of individuals with documented CAD are less than 45 years [
1,
2].
The PCAD is defined, in various studies, as having an age of onset ranging from 30 to 56 years. Clinical studies have affirmed that patients with PCAD have a different clinical presentation, associated CAD risk factors, and coronary angiographic profile compared with the MCAD [
2‐
4].
Patients with PCAD belong to a particular subgroup that needs much more attention since its impact on individuals, families and the society is devastating. Studies on PCAD in certain countries may vary relevant to the populations studied, and the data on PCAD available in Iraq is scarce. This study was aimed at examining the prevalence, clinical presentations, associated cardiovascular risk factors, coronary angiographic profile, and therapeutic options in the PCAD compared to MCAD.
Discussion
This study showed an alarming higher rate of PCAD compared to most of reports and studies conducted worldwide. This rate is higher than rates reported by Mohammad et al. from Iraq, Prashanth et al. from Oman and Al-Nozha et al. from Suadia Arabia [
16‐
18]. At the same time it is much higher than the reported rates of documented CAD in young populations in USA, India, China and Japan [
19‐
22]. On the contrary, it is lower only than the rate reported exclusively by Zahrni et al. who found 55 % of CAD in Malaysian is of premature onset, and this is probably related to the mean age difference between both studies [
23]. The age of PCAD presentation in the current study is much younger than the mean age for Zahrni et al., and is comparable to Roxona Sadeghi et al. from Iran [
23,
24].
In consistence with the results found by Zahrni et al., Tahir et al., and Prashanth et al., the current study showed higher incidence of ACS compared to chronic stable angina among premature group [
17,
23,
25]. But Abu Siddique et al. showed higher rates of chronic stable angina and not ACS among PCAD [
26]. Interestingly among the latter group, males are more likely to present with STEMI as compared to females. This finding has also been demonstrated in other observational and retrospective analyses worldwide. This group of patients represents an area for further study and possible future interventions. Currently, there are prospective studies ongoing to evaluate subclinical markers of atherosclerosis and indeed some currently unknown risk factors may be responsible for this finding [
27,
28].
This study, like Nafakhi though unlike Abu Siddique et al., revealed no significant difference in the prevalence of hypertension between premature and mature CAD [
26,
29]. Noeman et al. found similar rate to the current study of hypertension among PCAD in Pakistan [
30]. Compared to Prashanth et al. and Mahnoosh Foroughi et al., while this study found a lower rate of obesity among PCAD, it concluded a similar one among female gender [
17,
31]. This gender difference could be attributed to many etiologies including cultural customs and social norms of the society.
The study, in accordance with Tahir et al. and Badran et al., showed a significant difference in the prevalence of diabetes mellitus between premature and mature CAD. Unlike Badran et al., however, it showed no significant gender difference of prevalence of diabetes mellitus in the PCAD [
25,
32]. Besides, the study showed a significantly higher incidence of dyslipidemia in PCAD that is similar to what Penida et al. found [
33].
The rate of smoking among PCAD was lower in this study compared to Roxana Sadeghi et al. (30 % vs. 46 %) [
24]. Smoking was rare among females in this study likely because yet it is not popular among women in the Kurdish society. Positive family history of CAD among the premature group of this study is similar to Mahnoosh Foroughi et al. study from Iran [
31]. Nevertheless, higher percentages of positive family history were found in Turkey by Yildrim et al. [
34]. Though recognized as an important risk factor for ACS in PCAD, HIV significantly impacts the trend of mortality increase in such patients. Interestingly, however, our study did not show any registered cases of which HIV caused PCAD [
35].
Similar to Ibrahim Shah et al. and Badran et al. studies we found a significant higher rate of mild coronary lesions among premature group though it is in contrast to S. Sadiq Shah et al., who reported no statistical difference in the severity of coronary lesions between premature and mature CAD [
32,
36,
37]. This finding, in the current study, possibly related to short duration of clustering of risk factors among premature group.
Evaluating the types of coronary lesion, Tahir et al. reported no statistical difference between premature and mature CAD. This study showed a significant higher rate of type A lesions among PCAD [
25]. In consistence with Badran et al., Almayali and Christus et al., the study found higher rate of single vessel disease among PCAD [
32,
38,
39]. Conversely, it showed a significant higher rate of 3VD/ 4VD among mature group. Similar results were reported by many studies, including Tewari et al. [
25,
32,
39,
40]. In contrast with Farhan et al., this study showed a significantly higher rate of 3VD and 4VD among males with PCAD [
41].
In accordance with the Abu Siddique et al. and Nafakhi, the distribution of major epicardial coronary artery involvement in this study was independent of the age [
26,
30]. The therapeutic options, including the CABG that were significantly more doable in the MCAD and medical treatments that were more common in PCAD provided that there was less complex angiographic profile among PCAD compared to MCAD, were similar to Chrustus et al. [
39].
Study limitations
There are a few main limitations to this study. To start with, only patients presented with symptoms and assigned for an angiogram were diagnosed with CAD that might limit the generalizability of the results. Though the study was a single center experience that could result in a referral bias, it reflected the trends of prematurity of CAD all over the country given a close attitude, genetics and socio economic similarities among the population. No data on follow up as well as the coronary imaging (e.g. IVUS) findings of patients included were collected. Nevertheless, this study, which is the first detailed one conducted on PCAD in the country, identified an unmet scientific need in the area, enrolled a relatively large sample size to investigate the prevalence of PCAD, and clearly defined data on all patients.
Competing interests
The authors declare that they have no competing interests.
Authors’ contributions
AMM has made substantial contributions to conception and design of the study, data and statistical analysis, and writing and submitting the manuscript. HJ and SK have contributed in data acquisition and manuscript revision. All authors have read and approved the final manuscript to be published.
AMM. Is an interventional cardiologist at Duhok Heart Center and Professor (Assistant) of Cardiology at Department of Medicine, Medical School, Faculty of Medical Sciences, University of Duhok, Duhok, Kurdistan, Iraq .
HJ. Cardiologist, Duhok Heart Center, Duhok, Kurdistan, Iraq
SK. Professor of Cardiology, Department of Medicine, Medical School, Faculty of Medical Sciences, University of Duhok, Kurdistan, Iraq.