Clinical Review: Management of Patients with Acute ST-Elevation Myocardial Infarction.

AIMS: The aim was to assess the quality of practice provided to acute ST-elevation myocardial infarction (STEMI) patients at the cardiac center, within a specified time frame and identify possible areas of improvement. SETTINGS AND
DESIGN: This is a retrospective standards-based clinical review, including adults diagnosed with acute STEMI between January 1, 2016 and January 1, 2017 of cases admitted and managed at the respective cardiac center. SUBJECTS AND METHODS: The study was designed according to recommendations provided by the National Institute for Health and Care Excellence guidelines: "The acute management of myocardial infarction with ST-segment elevation;" alongside, the local standard: door-to-balloon time ≤90 min, adopted from the American Heart Association. STATISTICAL ANALYSIS USED: Data analysis was done through excel and SPSS for advanced statistical calculations. P < 0.05 was considered to be statically significant.
RESULTS: In total, 277 patients were included in the study. About 72% underwent primary percutaneous coronary intervention with 62 min as median door-to-balloon time. Door-to-balloon time >90 min was significantly higher when patients presented outside official hospital hours (P = 0.039). Transradial route was chosen in 77.7% of the cases.
CONCLUSIONS: Practice at the cardiac center was found to show good compliance with the guidelines. However, door-to-balloon time for procedures performed out of official hospital working hours was slightly outside the recommended limit. Copyright:

INTRODUCTION

Atheromatous coronary artery disease is caused by atherosclerosis in patients predisposed to the condition by risk factors such as male gender, dyslipidemia, diabetes mellitus, smoking, and genetic traits. Atherosclerosis leads to the formation of plaques, which may result in reduced perfusion of cardiac tissues supplied by the diseased coronary artery. Myocardial infarction (MI) is caused by plaque rupture, initiation of the thrombotic cascade, and partial to total occlusion of the relevant coronary artery.[1]

ST-elevation MI (STEMI) involves complete occlusion of a coronary artery, most commonly as a result of a thrombus and can result in transmural MI.[23]

The primary aim of acute STEMI management is the restoration of coronary blood supply as quickly as possible since the delay in reperfusion was found to be associated with increased risk of impaired left ventricular systolic function and death. The main reperfusion methods include primary percutaneous coronary intervention (PPCI), where reperfusion is achieved through mechanical techniques such as coronary angioplasty, thrombus extraction, and stenting and fibrinolysis through the administration of fibrinolytic drugs. Meta-analysis of randomized clinical trials has shown PPCI to be superior to fibrinolysis with lower mortality rates, re-infarction, and stroke; provided that the PPCI-related time delay is not excessive.[45]

Factors that affect timely reperfusion include late presentation to the hospital, also termed patient-related delay, interhospital transfer times, and prolonged door-to-balloon inflation times at the PCI center.

Ischemic heart disease is the leading cause of death in Bahrain, comprising 13.4% of all deaths, killing 0.4 thousand people, with significantly the highest number of sum of years of life lost due to premature mortality in the year 2012 according to the latest WHO records.[6]

In this clinical review, we look at the management of acute STEMI in the recent clinical practice at the cardiac center, in particular, the different reperfusion strategies.

This study aims at critical evaluation of the most recent clinical practice, to identify possible grounds for improvement and improve clinical outcome.

SUBJECTS AND METHODS

Design and standards

This study is a retrospective, standards-based clinical review, assessing the acute management care provided to 277 patients admitted to the respective cardiac center with ST-elevation myocardial infection between January 1, 2016 and January 1, 2017. The study was designed according to recommendations provided by the National Institute for Health and Care Excellence (NICE) guidelines: “The acute management of myocardial infarction with ST-segment elevation;”[7] alongside, the local standard: door-to-balloon time ≤90 min, adopted from the American Heart Association.[8]

The data were further divided into presentations within (7 am to 2 pm) and out of (2 pm to 7 am) official hospital office hours.

Study settings and inclusion and exclusion criteria

All adult cases (of 18 years or more), with a diagnosis of acute MI, who presented to, and were managed at the cardiac center, over the 12-month period between January 1, 2016 and January 1, 2017 were reviewed.

Only patients with discharge diagnosis of acute STEMI were included. Patients who underwent successful fibrinolysis at other hospitals and were referred to the cardiac center for further management were excluded.

Data collection and analysis

Data collection was carried out in March and April 2017, after receiving ethical approval from the respective cardiac center. Data was collected from electronic and manual patient records and was entered directly into Excel spreadsheet.

National ID numbers of cases in the inclusion criteria were recorded from the coronary care unit and were used to access patient files. Data analysis was done through excel and SPSS, IBM Corp. Released 2017. IBM SPSS Statistics for Windows, Version 25.0. Armonk, NY: IBM Corp. for advanced statistical calculations. P < 0.05 was considered to be statically significant.

RESULTS

Patient characteristics

In total, 278 cases met the inclusion criteria of the study; one case was excluded due to restricted file access (Very Important Personnel (VVIP) patient), making the total number of patient records reviewed 277 [Table 1a].

Table 1a

Patients’ demographics

Gender	Number of candidates (%)	Mean age (years)	Ethnicity
			Bahraini (local)	Non-Bahraini
Male	246 (88.8)	52 (29-87)	125	121
Female	31 (11.2)	64.5 (42-89)	19	12
Total	277

All patients with discharge diagnosis of MI were initially diagnosed according to the universal definition of MI, based on suggestive electrocardiogram changes, cardiac enzymes, and presenting signs and symptoms. As recommended by the NICE guidelines, no patient was labeled eligible or ineligible for reperfusion based solely on their level of consciousness.

In total, 197 patients (71%) of patients received primary PCI, 12 patients (4%) received fibrinolysis, and 61 patients (22%) were offered rescue PCI after failed fibrinolysis (includes primary and referred patients). Eight (3%) patients did not receive reperfusion intervention as four had normal coronary arteries on angiography, three patients had expired in the catheter laboratory due to cardiogenic shock, and one had very late presentation (>24 h from symptom onset).

Of all cases, 64.3% arrived at the cardiac center outside the official working hours (7 am to 2 pm). Most of the cases managed for acute STEMI at the cardiac center are referrals from other hospitals, making treatment decision-making, outcomes, and transfer delay important factors affecting timely reperfusion in those patients [Figure 1a].

Figure 1

(a) T he source of patients diagnosed with acute ST-elevation myocardial infarction at the cardiac center from January 1, 2016 to January 1, 2017. (b) Description of symptom onset times and record availability

Time of onset of chest pain to arrival at first medical contact, time was reviewed when the respective records were available (patient-related delay) (185 patients)

The NICE guidelines have different recommendations regarding the reperfusion management for patients presenting to the hospital within 12 h of symptom onset and those who exceed the 12 h, respectively. Hence, the data have been looked at accordingly [Table 1b].

Table 1b

Patient-related delay, type of presentation, and their relation to the type of reperfusion

Time of symptom onset	Number of candidates (%)	Type of presentation	Number of candidates (%)	Type of reperfusion
				Primary PCI	Fibrinolysis	Rescue PCI after failed fibrinolysis	No intervention
≤12 h	149 (54)	Primary cases	76 (27)	61 (80)	10 (15)	1 (1)	3 (4)
		Referrals	73 (26)	54 (74)	0 (0)	18 (25)	1 (1)
>12 h	36 (13)	Primary cases	30 (11)	29 (97)			1 (3)
		Referrals	6 (2)			6 (100)	0
No record	92 (33)	Primary cases	7 (3)	5 (71)	2 (29)	0 (0)	0 (0)
		Referrals	85 (31)	48 (5)	0 (0)	36 (42)	1 (1)
Total	277			197	12	61	8

PCI: Percutaneous coronary intervention

Our results indicate that 149 (53.8%) patients presented within 12 h of symptom onset [Figure 1b], of which 76 were primary cases of the cardiac center and 73 were referrals from other hospitals. Of the patients with the first presentation within 12 h of symptom onset (76), 61 (80.3%) underwent primary PCI, successful fibrinolysis was administered to 10 patients, with median door-to-needle time (DTN time) of 21 min (range 5–37 min).

Thirty-six patients presented later than 12 h from symptom onset with continuing ischemia, of which six were referrals of failed fibrinolysis from other hospitals that were offered rescue PCI, and 30 primary cases, of which 29 received coronary angiography with follow-on PCI if indicated [Table 1a].

Coronary angiography with appropriate PCI revascularization procedures was performed in all patients with cardiogenic shock, with the exception of one patient who expired shortly after admission in the cardiac catheterization laboratory.

In total, 92 cases had no symptom onset record in the respective reviewed files, most of which were referrals. Therefore, they were not assessed for the NICE guideline recommendations that required symptom onset time.

Door-to-balloon times and delay

Our data were analyzed for distribution using the Shapiro–Wilk test and the results showed that the data were leptokurtic with significant positive skew (+6.99, P = 0.00 [<0.05]) indicating that the data are not normally distributed; therefore, the median was used to represent the data. One record of the door-to-balloon time was an extreme outlier due to patient factors and was excluded from the statistical calculations. This particular patient had extensive occlusion in the left anterior descending artery with previous coronary stenting and renal impairment. The patient was offered diagnostic angiogram, and the case was discussed for the CABG procedure, but the patient was eventually managed by PCI due to his co-morbidities.

In the course of the 12-month period, a total of 197 (72%) cases of acute STEMI underwent primary PCI at the cardiac center with a median door-to-balloon time of 62 min and PCI related delay of 41 min [Figure 2a]. Out of the 197 patients who underwent PCI, six patients did not have recorded PCI reports and therefore were excluded from the statistical calculations requiring the respective data.

Figure 2

(a) Description of total door-to-balloon times. (b) Description of the spread of arrival times of patients with door-to-balloon exceeding 90 min over the course of 24 h. (c) Description of the route of access chosen during percutaneous coronary intervention procedures performed and thrombus aspiration

A total of 115 patients presented to the cardiac center within 12 h of symptom onset and were managed by the primary PCI with median door-to-balloon time of 69 min and PCI related delay of 55 min. Two patients were excluded from this statistical calculation for missing PCI records [Table 2].

Table 2

Guideline standards and summary of results

Summary of results Guideline standards	Results
1. Immediately assess eligibility (irrespective of age, ethnicity, or sex) for coronary reperfusion therapy (either primary PCI or fibrinolysis) in people with acute STEMI 1.1.1	100%	277/277
2. Do not use level of consciousness after cardiac arrest caused by suspected acute STEMI to determine whether a person is eligible for coronary angiography (with follow-on primary PCI if indicated) 1.1.2 ?	100%	277/277
3. Deliver coronary reperfusion therapy (either primary PCI or fibrinolysis) as quickly as possible for eligible people with acute STEMI 1.1.3	100%	276/276
Patients presenting within 12 h from symptom onset
4.1. Primary PCI given for patients presenting within 12 h provided that door-to-balloon time is ≤90 min (local guideline of the cardiac center adopted from AHA)
All working hours	80.9%	93/115
Within working hours	87.2%	34/39
On-call hours	77.6%	59/76
4.2. Offer coronary angiography, with follow-on primary PCI if indicated, as the preferred coronary reperfusion strategy for people with acute STEMI if: Presentation is within 12 h of onset of symptoms and primary PCI can be delivered within 120 min of the time when fibrinolysis could have been given 1.1.4	80.3%	61/76
4.3. Patients to whom fibrinolysis offered assessed for fibrinolysis failure after 60-90 min ECG	100%	11/11
4.4. Patients with failed fibrinolysis should undergo immediate angiography with follow-on PCI if indicated	100%	1/1
4.5. Fibrinolytic therapy should not be repeated after failure	100%	1/1
4.6. Consider thrombus aspiration during primary PCI for people with acute STEMI	36%	71/197
4.7. Consider radial (in preference to femoral) arterial access for people undergoing coronary angiography (with follow-on primary PCI if indicated)	77.7%	153/197
Patients presenting later than 12 h from symptom onset
5.1. Coronary angiography with follow-on PCI should be considered in patients with continuing ischemia	97%	35/36
5.2. Coronary angiography with view into revascularization should be considered in patients who present with cardiogenic shock or those who go on to develop it	100%	4/4

STEMI: ST-elevation myocardial infarction, PCI: Percutaneous coronary intervention, AHA: American Heart Association, ECG: Electrocardiogram

In addition, to further assess and evaluate the quality of clinical practice, we looked at door-to-balloon times within and outside of normal hospital working hours (7 AM to 2 PM). Median door-to-balloon time within working hours was 61 min, compared to 99 min for cases presenting out of official working hours [Table 3].

Table 3

Percutaneous coronary intervention-related delay within and out of official working hours

Number of patients	Median DTB time (min)	Median DTN time (min)	Median PCI-related delay (min)
Total patients (143)	62	6	56
Within official working hours (7 am to 2 pm) (49)	61	13	48
Out of official working hours (2 pm to 7 am) (94)	99	6	70

PCI: Percutaneous coronary intervention, DTN: Door-to-needle, DTB: Door-to-balloon

Cross tabulation using Fisher exact showed that the number of cases with door-to-balloon time exceeding 90 min in patients arriving at the cardiac center after official working hours was significantly higher compared with those presenting within working hours.

(X2(1,193) = 4.28, P = 0.039 [<0.05]).

The odds ratio (OR) test performed was suggestive of a strong association between working hours and door-to-balloon time exceeding 90 min (OR: 2.629, 95% confidence interval: 1.026–6.737).

Figure 2b shows the spread of cases that exceeded the recommended door-to-balloon time over the course of 24 h.

Route of access and thrombus aspiration

The route of entry in the PCI procedures and consideration of thrombus aspiration are described in Figure 2c. Majority (77.7%) of PCI procedures during the 12 months' period were transradial. The transfemoral route was chosen in 20.8% of the cases.

Thrombus aspiration was performed in 36% of patients.

Twenty (7.2%) patients diagnosed with acute STEMI expired on the index admission. The most frequent cause of death was cardiogenic shock. Delay in timely reperfusion could not be very well assessed in this group of patients since records of the time of symptom onset (patient-related delay) were not recorded in a significant number of transfer patients (57%).

DISCUSSION

NICE provides six areas of assessment as quality standards that contribute to the prevention of preventable premature mortality, of which three apply to clinical management of acute STEMI.[9] Through this study, the current practice at the cardiac center was found coherent with the provided recommendations.

Our study shows that 71% of all acute STEMI patients at the cardiac center undergo PPCI, which is the preferred method of reperfusion according to the NICE guidelines. Comparatively, the Gulf COAST registry shows that only 10% of all acute STEMI patients in Oman, Kuwait, UAE, and Bahrain undergo PPCI.[10]

For patients presenting within 12 h from symptom onset, the cardiac center has a compliance of 80.9% with local guidelines, as most patients were offered primary PCI with a door-to-balloon time <90 min. This shows that adherence in the respective cardiac center compares favorably to centers in neighboring Gulf countries, as door-to-balloon time <90 min has been achieved in only 70%, 60%, and 50% in UAE, Kuwait, and Oman, respectively.[10] The Gulf COAST registry, based on data collected between January 2012 and January 2013 documents that the compliance with recommendations for door-to-balloon time not exceeding 90 min was 81% in Bahrain.[10] As this figure is very close to the compliance between January 2016 and January 2017 (80.9%), it indicates that the implementation of new strategies is needed to increase the compliance over the coming years.

Furthermore, the cardiac center has 80.3% compliance with the NICE guidelines recommending that PPCI is used as the reperfusion method if PCI-related delay does not exceed 120 min, for patients presenting within 12 h of symptom onset (1.1.4).

Regarding patients who presented later than 12 h from symptom onset, the cardiac center has a compliance of 97%, as those patients were offered coronary angiogram with follow-on PCI if indicated.

In majority of the cases, primary PCI was offered, and in 77.7% of patients, the transradial approach was used [Table 2], as it is associated with reduced chance of access site bleeding which, in turn, has been associated with reduced overall complications.[67891011] In addition, the transradial approach is associated with a shortened hospital stay, making it more economical than femoral access.[12] The transfemoral route was considered in highly critical patients for whom the transradial approach might not have been the most suitable choice in terms of procedural delay, use of intra-aortic balloon pump, and use of larger caliber PCI equipment not compatible with radial sheaths.

NICE guideline recommendations on thrombus aspiration were based on low- to very low-quality evidence lacking statistical strength, and therefore, it was not recommended to be routinely performed. Moreover, in two large-scale randomized control trials, comparison of the use of PCI alone versus PCI with routine thrombectomy has failed to demonstrate an improvement in the long-term outcome of procedures with thrombectomy in comparison with PCI alone. New evidence suggests that routine thrombus aspiration may be associated with stroke.[1314]

Fibrinolytic reperfusion was offered to patients with early presentation (arriving at the cardiac center within 1 h of symptom onset) and where it was assessed that performance of primary PCI would result in delay to reperfusion. All patients who were offered fibrinolysis were reperfused with DTN time of <40 min.

In efforts to improve the quality of care provided to acute STEMI patients, factors contributing to more desirable clinical outcomes have been extensively studied in the last couple of years. It has been shown that although shorter door-to-balloon time is a quality measure, its clinical benefit is confined to early presenting patients. Symptom onset-to-balloon time was suggested as a better measure of clinical outcome in patients with acute STEMI who receive PCI. Since door-to-balloon time is a fraction of the onset-to-balloon time, efforts in reducing delays in symptom onset to first medical contact should be considered.[515]

The main limitation of this study was the lack of complete information in the respective patient files in some cases, especially symptom onset time for patients referred from other hospitals.

CONCLUSIONS

Statistical results in this study provide evidence of good-quality clinical care in acute settings of ST-elevated MI with the center fulfilling recommended time criteria for primary PCI.

The center fulfilled the time criteria for the door-to-balloon time within hospital working hours (62 min) and just missed the recommended door-to-balloon inflation time of 90 min or less (99 min) for patients arriving outside of working hours when the performance of primary PCI requires that the PCI team be alerted from home and travel to the hospital for the procedure.

The small number of patients who received thrombolysis as the primary treatment at the cardiac center fulfilled the DTN time of 30 min or less.

Recommendations

In light of a long DTB time during on call hours (99 min), studies suggest the development of an in-house 24/7 STEMI program that is available during working and on call hours. There is evidence that such teams are proven to apply timely and effective reperfusion, with the potential to achieve lower DTB time, especially during “on-call” hours[16]

In a recent study analyzing the root causes of mortality in STEMI patients postprimary PCI, early recognition of MI symptoms by the patient and early seeking of health care was found to be among the top modifiable factors; therefore, we recommend that high-risk patients get sufficient education on the symptoms and signs of MI and be advised to seek medical help immediately[1718]

A re-analysis is recommended within 2–3 years to assess for the implementation of solution plans for areas of improvement highlighted in this study, as well as general quality of care provided to acute STEMI patients.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.