Frequency of Incomplete ST Segment Resolution After Successful Primary Percutaneous Coronary Intervention

primary Percutaneous Coronary Intervention (PCI) can be veri�ed on electrocardiogram through measuring ST Resolution (STR) and examination if their angiogram. Objective: The purpose of this research was to identify instances of after the primary PCI of partial STR and to investigate the characteristics associated with incomplete STR following primary PCI. Methods: At department of Interventional Cardiology of National Institute of Cardiovascular Disease (NICVD), Karachi, Pakistan, this Descriptive Cross-sectional study was conducted. The inclusion criteria set for data collection were patients with age between 18 to 65 years of both genders presented with complain of chest pain 12 hour previously and now diagnosed with acute STEMI, and undergoing successful primary PCI were included in the study. Results: Out of 196 patients, male was 74.5% while female were 25.5%. The Mean age of patients was 52.78±7.81 years. Out of 196 patients, with acute STEMI, 35.2% (69) had Incomplete STR after a successful primary PCI. When applying chi square on study variables with Incomplete STR after a successful primary PCI was found to be not associated with patient's baseline characteristics. Conclusions: Our research discovered that a considerable proportion of patients with STEMI have Incomplete STR after �rst PCI. However, no correlation between STR and baseline patient characteristics was observed.


I N T R O D U C T I O N
The success of primary Percutaneous Coronary Intervention (PCI) can be veri ed on electrocardiogram through measuring ST Resolution (STR) and examination if their angiogram. Objective: The purpose of this research was to identify instances of after the primary PCI of partial STR and to investigate the characteristics associated with incomplete STR following primary PCI. Methods: At department of Interventional Cardiology of National Institute of Cardiovascular Disease (NICVD), Karachi, Pakistan, this Descriptive Cross-sectional study was conducted. The inclusion criteria set for data collection were patients with age between 18 to 65 years of both genders presented with complain of chest pain 12 hour previously and now diagnosed with acute STEMI, and undergoing successful primary PCI were included in the study. Results: Out of 196 patients, male was 74.5% while female were 25.5%. The Mean age of patients was 52.78±7.81 years. Out of 196 patients, with acute STEMI, 35.2% (69) had Incomplete STR after a successful primary PCI. When applying chi square on study variables with Incomplete STR after a successful primary PCI was found to be not associated with patient's baseline characteristics. Conclusions: Our research discovered that a considerable proportion of patients with STEMI have Incomplete STR after rst PCI. However, no correlation between STR and baseline patient characteristics was observed. pro le of the patients such as age, gender, smoking status, hypertension, family history and diabetes mellitus of CAD were retrieved. A verbal informed permission was obtained from each participant before the study's participation by outlining its goals, methods, dangers, and bene ts. All PCI operations were documented by a consultant cardiologist with more than 5 years of experience. Patients were pretreated with aspirin and a second oral antiplatelet drug, such as clopidogrel or ticagrelor, while post PCI angiography and ECG (before the operation & after 30 minutes of procedure) were conducted by competent cardiologists and personnel. STEMI was classi ed as per the de ned operational de nition. Incomplete STR was recorded for the selected patients. Strictly following inclusion and exclusion criteria was controlled for confounding variables and biases. The collected data was analysed in SPSS version-21. P-values of less than ve percent were considered statistically signi cant. Piecharts were employed for the visual representation of data.

M E T H O D
poor symptoms of myocardial perfusion, manifested by a continuous ST segment increase and incomplete removal of STR Elevation. After PCI, the presence or absence of STRs is an important indication of left ventricular dysfunction and poor clinical outcome [9]. Monitoring STR after successful primary PCI for optimal perfusion in the cardiac micro vessels is the most convenient way [10]. Recent studies have shown that STR is a useful prognostic factor for late revascularization and myocardial infarction recurrence rate, but it does not predict long-term mortality in STEMI patients following PPCI [11]. In several studies, complete STR is de ned as ST-segment decline of more than 70% of pre-PCI ST-segment elevation. The angiographic surrogate for myocardial perfusion are two commonly accessible procedures, namely recovery of electrocardiographic STR and restoration of normal myocardial blush (MB) [12]. According to current understanding, resolution or recovery of the ST-segment after reperfusion treatment indicates successful microvascular perfusion of cardiac tissue salvaging myocardium [13]. Numerous thrombolytic investigations have provided the most conclusive evidence for STR's predictive usefulness. [14]. However, signi cant variations in the degree of epicedial blood ow restoration were detected between PPCI and thrombolysis: 60% with thrombolysis versus close to 95% with PPCI, as well as the rate of blood ow restoration [15]. The purpose of this research was to identify instances of incomplete STR after primary PCI and to investigate the characteristics associated with incomplete STR during primary PCI.
Study was conducted at Department of Interventional Cardiology at National Institute of Cardiovascular Disease (NICVD), Karachi, Pakistan as descriptive cross-sectional. WHO sample size calculator version 2.0 were used and total 196 patients were included to determine the frequency of incomplete ST-segment elevation resolution 95% con dence interval, 7% of margin of error and 49.4% of expected prevalence were targeted. P value 0.005 were considered signi cant. Non-probability, and consecutive sampling technique were used for data collection. The inclusion criteria set for data collection were patients with age between 18 to 65 years of both genders presented with complain of chest pain 12 hour previously and now diagnosed with acute STEMI, and undergoing successful primary PCI were included in the study. Whereas patients who had previous history of any cardiac related surgery were excluded from the study. Prior to sampling or data collection, the study was approved by the ethical review committee of NICVD, Karachi, Pakistan. Research questionnaire was pre-designed in which the demographic

R E S U L T S
We recruited a total of 196 patients of either gender i.e., male or female with the age of 18 years to 65 years. Out of 196 patients, 74.5% were male and 25.5% were female. The Mean age of patients was 52.78±7.81 years. The Descriptive statistics of age and further strati ed in groups into frequency and Percentages presented in Table 1. Among all study subjects, 27.6% with diabetes mellitus, 51.5% with hypertension, 29.1% were smokers, and 9.2% had family history of CAD. The data revealed that people with hypertensive were more prone to CAD. Out of 196 patients, with acute STEMI, 35.2% (69) had Incomplete STR after a successful PCI. Incomplete STR after a successful PCI was found to be not associated with patient's baseline characteristics and family history of CAD. Among total study subjects, 27.6% with diabetes mellitus, 51.5% with hypertension, 29.1% were smokers, and 9.2% had family h i s t o r y o f C A D . T h e S T R b y D i f fe r e n t P a t i e n t Characteristics is presented in Table 1  The initial ECG suited for assessing STR after primary PCI is generally performed on the coronary care unit (CCU) as shown in gure 1.

Incomplete ST Segment Resolution After Successful Primary Percutaneous Coronary Intervention
The baseline characteristics of the patients were statistically analysed and the results showed that STR is not associated with initial characteristics of the patients, age, gender, diabetic mellitus, family history and hypertension. For a long time, the use of STR as a diagnostic tool in STEMI has been established in an age of thrombolytic therapy [16]. The role of STR in the current PCI era is not well understood due to the limitations of previous PCI studies, including the use of irregular stents, lack of information on drug-lled stents, lack of standardization of ECG time after reperfusion, and relatively short follow-up time [3]. STR has been proved to be a stronger predictive predictor than epicardial blood ow recovery, as seen in our ndings. As a result, STR may be a useful early-stage marker for predicting the outcome of AMI patients. The majority of trials assessed STR effect on clinical, angiographic, and outcome measures 30-120 minutes after PCI [8][9]. In 2009 Park S, et al., conducted study on "clinical predictors of incomplete STR in the patients with acute ST segment elevation myocardial infarction". Beside other study variables age, gender, hypertension, diabetes mellitus, and tobacco smoker were similar with our study. Age, gender, diabetes mellitus, tobacco smoker has no signi cant difference in partial, complete and incomplete STR. However, hypertension re ect higher signi cance with p value of <0.004 in incomplete STR group which contrast the statement of our study [17]. Similarly, another study was conducted in 587 patients to determine the magnitude of STR with an Acute Myocardial Infarction (AMI) after thrombolytic therapy (streptokinase) resulted in successful STR in short-and long-term outcomes [18]. It has been said that more than 90 mins of ST segment analysis is associated with reperfusion which leads to induced cell death. However, for that cause, we evaluated STR for 30 min after PCI. Another hypothesis contends that TIMI blush grading may be used to assess myocardial perfusion following PPCI. Longer angiographic recordings need to be made in order for blush grade analysis to be possible. Since our goal was to investigate ST-segment resolution and there was no speci c procedure for When applying chi square on study variables with Incomplete STR after a successful primary PCI was found to be not associated with patient's baseline characteristics and family history of CAD. The STR by Different Patient Characteristics along with their p values are presented in Table 2. Although the very low incidence rate of incomplete STR among male, Age 18 to 50%, nondiabetic, nonhypertensive, non-smoker and with no family history of CAD were predicted as shown in   C O N C L U S I O N S angiographic examination, we examined TIMI ow in sub epicardial arteries [19]. In our study we divided age into two group i.e. 18 to 50 years and 51 to 65 years and found out age has not effect in incomplete STR. Similar result was declared by Prasad A, et al, they divided the Age in 4 categories which evaluated in respect of mortality as well. As per their study ndings age of patient signi cantly effect in partial and complete STR but in incomplete STR no association was predicted (p value 0.33) [20]. In Iraq, the most recent study was conducted for evaluating the factors that are associated with incomplete ST segment elevation. The association of above-mentioned factors in the population of Iraq shows that geographically the diseases vary and the may be genetic and environmental factors are also causing the variation in the symptoms and factors [21].
Our study showed a signi cant number of patients presented with STEMI had Incomplete STR after primary PCI. However, no association was found between STR and patient's baseline characteristics. It is important to identify factors affecting STR to improve the outcomes of STEMI.

C o n  i c t s o f I n t e r e s t
The authors declare no con ict of interest.

S o u r c e o f F u n d i n g
The author(s) received no nancial support for the research, authorship and/or publication of this article [3]