Resolution Extent of ST Segment Post Primary Percutaneous Coronary Intervention a Predictor of Better Outcomes View PDF

MI defined as myocardial necrosis those results from complete obstruction of coronary artery with sign and symptom of myocardial ischemia. MI is a clinical syndrome characterized by features of myocardial ischemia, persistent elevation of ST segment of ECG and elevation of myocardial markers. Recently the mortality due to MI has declined as a result of decreased of rate of MI and proper management, this fall associated with increased in rate of unstable angina and non ST segment elevation of MI. Patients with STEMI who receive aggressive pharmacologic reperfusion therapy have short-term mortality rate (as part of a randomized trial) is in the range of 6.5% to 7.5% whereas the mortality rate in STEMI patients in overall community is 15% to 20%. 7. About 30% of patients with STEMI who are eligible to receive reperfusion therapy do not receive that lifesaving treatment [1-8]. The risk of adverse outcomes of MI correlates with the degree of ST-segment elevation on the ECG, myocardial marker and location of infarction. Even patient with left bundle branch block can be diagnosed as acute MI from ECG when there is more deviation of ST segment and QRS in addition to elevation of myocardial markers. The 12-lead ECG also provides noninvasive information about the success of reperfusion for STEMI and also provides diagnostic and prognostic information [9,10]. Also, there is a correlation between the number of ECG leads showing ST-segment deviation and mortality rate. Patients with MI and have 8-9 leads with ST-segment deviation have 3-4 times the mortality of patients with only 2-3 leads with ST-segment deviation. The duration of infarction time, as estimated from ST-segment monitoring, correlates with myocardial infarct size, ratio of infarct size to the area at risk, and degree of regional wall motion abnormality observed subsequently [11], reperfusion regime for patient with acute MI aim to normalize flow to epicedial coronary artery in addition to improve actual myocardial function in the infarct zone. Myocardial perfusion cannot be improved adequately without restoration of flow in the infarct-related artery.
Yet, even patients with grade 3 TIMI flow of affected coronary artery may not achieve adequate myocardial function restoration, and this is my be correlated with a great delay between the onset of MI symptoms and restoration of coronary artery flow [12]. Myocardial reperfusion achieved by either pharmacological agent (fibrinolysis) or mechanical (coronary intervention). The two major impediments to normalization of myocardial perfusion are microvascualr damage and reperfusion injury. Obstruction of the distal microvasculature of the infarct-related artery is due to micro emboli [13-17]. Fibrinolysis may exacerbate micro embolization because of the exposure of clot-bound thrombin, an extremely potent platelet agonist. Spasm of coronary can also occur in the infarct related artery because of the release of substances from activated platelets. 

There are Several techniques can be used to evaluate patient for adequate myocardial perfusion, one of them is ECG so that ST-segment resolution  after coronary artery revascularization is strongly predicts outcome in STEMI patients. Inadequate restoration of ST segment after reperfusion of coronary artery indicates that the patient is more liable for complication such as development of acute and late left ventricular failure and has high mortality rate than those with good resolution of ST segment. Early coronary artery intervention undoubtedly improves survival in patients with STEMI. The benefit of reperfusion therapy appears to be greatest when it’s performed as early as possible 16. The infarct artery can also be perfused by a catheter-based strategy. This approach has now performed by using a balloon catheter over a guide wire with using a potent ant platelet therapy (intravenous glycoprotein [GP] IIb/IIIa inhibitors and P2Y12 adenosine triphosphate [ADP] antagonists), coronary stents, with or without thrombectomy [18]. When PCI is used without fibrinolysis therapy, it is called primary PCI whereas rescue PCI when fibrinolysis has failed to achieve adequate reperfusion then patient referred for intervention. Several studies have reported that referral of patient to a PCI center is superior to fibrinolysis administered in a local hospital; such studies were conducted in dedicated health care systems with extremely short transportation and door-to-balloon times at the PCI centers. Some evidence has suggested that if there is delay   of primary PCI longer than 1.5 hours, the complication and mortality advantage compared with administration of fibrinolysis drugs is lost 35, to assess patient with acute STEMI for adequate reperfusion:

• Assess the time from onset of symptom which should be less than 12 hours.
• Assess time from first medical contact to PCI (door-balloon time) which should be 1.5 hours.
• It is best to conceive of circumstances in which fibrinolysis or an invasive strategy is generally preferred [19].

PCI strategy is generally preferred over fibrinolysis and especially when there is greater risk. This risk may be from the acute STEMI itself (hypotension, Killip Class ≥ II) or from high risk of bleeding if fibrinolysis were used, so that When a PCI operator and team is available and can implement an invasive procedure (door-to-balloon time <1.5 hours), it is preferable to take the STEMI patient to the catheterization laboratory rather than fibrinolysis. Because of the high risk of intracranial hemorrhage with using of fibrinolysis for old age patient or contraindication for fibrinolysis, those patients are probably treated better with PCI, provided that there is no excessive delay. Finally, when the diagnosis is in doubt, an invasive strategy is preferred over fibrinolysis [20].

The duration of the prospective study conducted at Al Najaf Cardiac Center was from 16/10/217 to 6/2/2018 and every patient was followed for one month. The study included data of 90iraqi patient diagnosed as acute STEMI. The diagnosis was based on WHO criteria for acute myocardial infarction, i.e., presence of any two of the following:

• Chest pain consistent with acute myocardial infarction of less than 24 hrs. duration,
• Electrocardiography changes, i.e., (ST segment elevation > 0.2 mv in at least two contiguous chest leads or > 0.1mv in at least two contiguous limb leads, new or presumably New left bundle branch block on electrocardiogram
• Raised levels of cardiac enzymes CPK-MB more than double of the reference value or positive Troponin I test done with commercially available kits of Trop I.

Inclusion criteria

Only patients with ST elevated MI who underwent PPCI upon presentation, in emergency were included in the study. The study population was divided into two groups:

• Patients with ST segment resolution on Electrocardiogram (done after 60 min of PPCI).
• Patients without ST segment resolution on Electrocardiogram (done after 60 min of PPCI).

Exclusion criteria

Cardiogenic shock, unconscious patient, ends stage renal disease. A detailed history was taken, particularly of age, sex, occupation, address, history of smoking, Diabetes Mellitus, hypertension and family history of ischemic heart disease. Complete physical examination of patients was done upon presentation in Emergency and important parameters such as pulse and blood pressure were noted. Patients followed up frequently regarding Pulse, ECG changes and complications if any, were monitored till discharge of the patient from hospital and then followed for one month. The end point was a composite of recurrent ischemic chest pain, Heart failure or death. Time from onset of chest pain to presentation of patient in emergency was noted through history of patient. ECG recordings of patients were taken upon presentation in the emergency. ST elevation was recorded in millimeters from the lead in which maximum elevation was observed. Repeat ECG was performed after 60 minutes from PPCI. ST resolution was defined as a reduction of > 50% ST segment elevation after PPCI. Follow up was conducted for each patient throughout his or her hospital stay. The major complications noted were recurrent ischemic chest pain, heart failure, arrhythmia and death. Recurrent ischemic chest pain was documented from the history and ECG, Heart failure was assessed on the basis of clinical examination and echocardiography.

All data was analyzed by SPSS (statistical package for Social Sciences) version 12.0 for windows. Chi-Square test was used to compare the demographic characteristics and complications in both groups 0.05% level of significance were used. The data are reported as means±SD, percentages (%) or 95% confidence intervals (95% CI). All tests were two-tailed, and the level of significance was set at P ≤ 0.05.

A total of 90 patients were enrolled in the study, of these 78% were male and 22% were female. The overall mean age of the study participants was 56.37±12.76 years, (49%) were diabetic, (43%) were hypertensive and (53%) were current smoker (Table 1).

Table 1: Demographic characteristics of patients.

Table 2 shows that mean age in Group A was55.34±12.24 years while in group B was 57.40±13.37years P value=0.15. There was no significant difference between the comorbidities of the two groups of the 90 consecutive patients included in this prospective study, there were 74 (82%) patients who showed ST resolution in their post PPCI ECG taken after 60minutes (group A) while 16 (18%) patients showed no ST resolution (group B).

Table 2: Patient character and ST segment resolution.

Twenty six patients were underwent PPCI within 3hours after onset of symptoms, 25 (96%) of them showed ST resolution while (4%) did not show ST resolution. Among the 34 patients who underwent PPCI within 3-6 hrs. after onset of symptoms, 29 (85%) showed ST resolution and (15%) did not show ST resolution. Thirty patients were underwent PPCI within 6-12 hrs. after onset of symptoms and among them (66%) showed ST resolution and (34%) did not show ST resolution (chi-square=8.64 and p value=0.0133).

Table 3 shows the culprit lesion of coronary artery during PPCI. LAD culprit vessels were (51%), (85%) of them develop ST resolution and (15%) with no ST resolution value = 0.85. while 14(15%) of patients the culprit vessel were LCX, from them 11(79%) develop ST resolution and (21%) with no ST resolution P value = 0.74. Patients with RCA lesion were (33%), (80%) of them develop ST resolution and (20%) with no ST resolution p value = 0.75.

Table 3: Duration of chest pain.

Table 4 shows the relationship between these complications and presence or absence of ST resolution. There was a statistically significant difference in the incidence of all the complications between the two groups as shown by the p values in Table 2. Out of 90 patients, one died and his ECG did not show ST resolution in the post PPCI. Recurrent attack of ischemic chest pain were (25%) of patient with ST resolution and 56 of patient without ST resolution, p value = 0.006, (4%) of patient with ST resolution develop HF while those without ST resolution were (18%) develop HF, p value 0.032.

Table 4: Culprit coronary artery.

^*P value < 0.05 is significant

Table 5: Adverse effect within 1 month of PCI.

^*P value < 0.05 is significant.

Follow up of patient by ECG after primary PCI with ST segment elevation MI is worth full and cost effective to evaluate coronary artery reperfusion. Whereas coronary angiography is indicator for epicedial vessels revascularization, ST segment reduction gives a good reflection of micro vessels perfusion. Although successful pericardial vessel reperfusions is good indicator of prognosis, but the micro-vascular reperfusion strongly correlates with the late outcome, therefore ECG follow up is a good indicator of prognosis [21-23]. Current study showed that the incidence of adverse effect, in patients with ST resolution 60 min after PPCI, to be 29% compared with 81% among those without ST segment resolution (p < 0.001). Pedro Beraldo de Andrade I, et al. shows that there was a higher mortality rate in patients who did not achieve ST-segment elevation resolution. In the univariate analysis ischemia time were associated with increased odds of not obtaining ST-segment resolution, losing significance in the multivariate model [24]. This result correlate with study was done by Bhatia, et al. That showed the patients with STEMI with no ST resolution developed complications more than those who showed ST reduction. Of the patients who showed ST resolution, 38% developed complications compared to 83%of the patients from the non-ST resolution group (P<0.001). Also Aderson study showed that presence or absence of ST improvement after reperfusion therapy is a useful predictor of mortality in patient with STEMI. In this study we noted that only (25%) patients from ST reduction suffer from recurrent chest pain while (56%) from non-ST resolution group developed recurrent chest pain in their early clinical outcome (p < 0.001). In pre-specified analysis of the randomized trial "Harmonizing Outcomes with Revascularization and Stents in Acute Myocardial Infarction" (HORIZONS-AMI), comprising 2,484 of 3,345 patients undergoing primary PCI, the rate of resolution of ST-segment was 50.5%, with a lower incidence of death, reinfarction, target vessel revascularization, and stent thrombosis in this group [25]. This result supported by study done by Ioannisvogiatzis et al. Also showed that recurrent angina was observed in 42.1% of the patients who showed no ST resolution while 30.8 % of the patients who showed ST resolution experienced recurrent ischemic chest pain. In our results we observed that the incidence of Heart failure was 3(4%) % in patients with ST resolution and (18%) in patients without ST resolution (p < 0.001), during follow up, this results are supported by study carried out by the Shlomi Matetzky, et al. They showed that 28% reduced ejection fraction of left ventricle in those patients without ST resolution vs. 19% in patient with improved ST resolution. Also Tomaszuk-Kazberuk, et al. supports this finding. Their results correlate with above study and showed that frequency of Left Ventricular dysfunction was more prevalent in post STEMI patients who did not get ST reduction and they concluded that improvement of LV systolic function is linked to ST resolution. Lee SG, et al. studies the relation between ST resolution and left ventricular recovery. Their finding showed that   STEMI with ST segment reduction the LV ejection fraction and muscle contractility improved significantly. While in those without ST resolution, changes relating to LV function were insignificant thus. In fact Schroeder et al reported that STEMI patient with ST segment resolution <50% was independent indicator of early mortality (p = 0.0001). Calculation of ST reduction after initial thrombolytic therapy can also be used as a tool to identify candidates for early invasive procedures such as PCI.

Current study revealed that patient with early submitted to revascularization after presented symptom of STEMI has more resolution of ST segment p value=0.0133. Ram?nas Unikas, Povilas Budrys, et al. show that patients in the incomplete STR group had longer symptom-onset-to-balloon and door-to-balloon intervals. TIMI3 flow after PPCI was more common in the complete STR group. TIMI flow ≤ 2 after PCI, AMI and symptom onset-to-balloon time were inversely associated with STR (beta coefficients -28.635, -28.611, and -0.917, respectively). AMI (OR = 29.9), symptom onset-to-balloon time (OR = 1.7) and patient's age (OR = 1.1) were associated with an increased likelihood of having incomplete STR.

The extent of ST segment reduction after reperfusion of coronary artery is a good a predictor of patient in hospital and short term out com of death, heart failure and recurrent ischemia.

Early presentation of patient with STEMI and early revascularization are recommended and very effective to achieve ST resolution and as a result yield to good patient clinical outcome.

1. Thygesen K1, Alpert JS, Jaffe AS, Simoons ML, Chaitman BR, et al. (2012) Third universal definition of myocardial infarction. Eur Heart J 33: 2551-2567.
2. Ibanez B, James S, Agewall S, Antunes MJ, Bucciarelli-Ducci C, et al. (2018) 2017 ESC Guidelines for the management of acute myocardial infarction in patients presenting with ST-segment elevation: The Task Force for the management of acute myocardial infarction in patients presenting with ST-segment elevation of the European Society of Cardiology (ESC). Eur Heart J 39: 119-177.
3. Goldberg RJ, Glatfelter K, Burbank-Schmidt E, Lessard D, Gore JM (2006) Trends in community mortality due to coronary heart disease. Am Heart J 151: 501-507.
4. Kamalesh M, Subramanian U, Sawada S, Tierney W, Ariana A (2005) Similar decline in post-myocardial infarction mortality among subjects with and without diabetes. Am J Med Sci 329: 228-233.
5. Myerson M1, Coady S, Taylor H, Rosamond WD, Goff DC Jr (2009) Declining severity of myocardial infarction from 1987 to 2002: The Atherosclerosis Risk in Communities (ARIC) Study. Circulation 119: 503-514.
6. Lloyd-Jones D, Adams R, Carnethon M, De Simone G, Ferguson TB, et al. (2009) Heart disease and stroke statistics, 2009 update: A report from the American Heart Association Statistics Committee and Stroke Statistics Subcommittee. Circulation 119: e21-e181.
7. Canto JG, Rogers WJ, Chandra NC, French WJ, Barron HV, et al. (2002) The association of sex and payer status on management and subsequent survival in acute myocardial infarction, Arch Intern Med 162: 587-593.
8. Fox KA, Steg PG, Eagle KA, Goodman SG, Anderson FA, et al. (2007) Decline in rates of death and heart failure in acute coronary syndromes, 1999-2006. JAMA 297: 1892-1900.
9. Scirica BM, Morrow DA, Sadowski Z, Ruda M, Nicolau JC, et al. (2007) A strategy of using Enoxaparin as adjunctive ant thrombin therapy reduces death and recurrent myocardial infarction in patients who achieve early ST-segment resolution after fibrinolysis therapy: The Extract-TIMI 25 ECG study. Eur Heart J 28:2070-2076.
10. Wagner GS, Macfarlane P, Wellens H, Josephson M, Gorgels A, et al. (2008) AHA/ACCF/HRS recommendations for the standardization and interpretation of the electrocardiogram: Part VI: Acute ischemia/infarction: A scientific statement from the American Heart Association Electrocardiography and Arrhythmias Committee, Council on Clinical Cardiology; the American College of Cardiology Foundation; and the Heart Rhythm Society: Endorsed by the International Society for Computerized Electro cardiology. J Am Coll Cardiol 53:1003-1011.
11. Krucoff MW, Johanson P, Baeza R, Crater SW, Dellborg M (2004) Clinical utility of serial and continuous ST-segment recovery assessment in patients with acute ST-elevation myocardial infarction: assessing the dynamics of pericardial and myocardial reperfusion. Circulation 110:e533-e539.
12. Appelbaum E, Kirtane AJ, Clark A, Pride YB, Gelfand EV, et al. (2009) Association of TIMI myocardial perfusion grade and ST-segment resolution with cardiovascular magnetic resonance measures of microvascualr obstruction and infarct size following ST-segment elevation myocardial infarction. J Thromb Thrombolysis 27: 123-129.
13. Kirtane AJ, Vafai JJ, Murphy SA, Aroesty JM, Sabatine MS, et al. (2006) Angiographically evident thrombus following fibrinolysis therapy is associated with impaired myocardial perfusion in STEMI: a CLARITY-TIMI 28 sub study. Eur Heart J 27: 2040-2045.
14. Rakowski T, Dziewierz A, Siudak Z, Mielecki W, Brzozowska-Czarnek A, et al. (2009) ST-segment resolution assessed immediately after primary percutaneous coronary intervention correlates with infarct size and left ventricular function in cardiac magnetic resonance at 1-year follow-up. J Electrocardiol 42:152-156.
15. Rekik S, Mnif S, Sahnoun M, Krichen S, Charfeddine H, et al. (2009) Total absence of ST-segment resolution after failed Thrombolysis is correlated with unfavorable short- and long-term outcomes despite successful rescue angioplasty. J Electrocardiol 42: 73-78.
16. White HD, Chew DP (2008) Acute myocardial infarction. Lancet 372: 570-584.
17. Busk M, Maeng M, Rasmussen K, Kelbaek H, Thayssen P, et al. (2008) The Danish multicentre randomized study of fibrinolysis therapy vs. primary angioplasty in acute myocardial infarction (the DANAMI-2 trial): Outcome after 3 years follow-up. Eur Heart J 29:1259-1266.
18. Antman EM, Hand M, Armstrong PW, Bates ER, Green LA, et al. (2008) 2007 Focused Update of the ACC/AHA 2004 Guidelines for the Management of Patients With ST-Elevation Myocardial Infarction: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines: developed in collaboration With the Canadian Cardiovascular Society endorsed by the American Academy of Family Physicians: 2007 Writing Group to Review New Evidence and Update the ACC/AHA 2004 Guidelines for the Management of Patients With ST-Elevation Myocardial Infarction, Writing on Behalf of the 2004 Writing Committee. Circulation 117: 296-329.
19. Pinto DS, Kirtane AJ, Nallamothu BK, Murphy SA, Cohen DJ, et al: Hospital delays in reperfusion for ST-elevation myocardial infarction: Implications when selecting a reperfusion strategy. Circulation 114: 2019-2025.
20. Danchin N1, Coste P, Ferrières J, Steg PG, Cottin Y, et al. (2008) Comparison of thrombolysis followed by broad use of percutaneous coronary intervention with primary percutaneous coronary intervention for ST-segment-elevation acute myocardial infarction: Data from the French registry on acute ST-elevation myocardial infarction (FAST-MI). Circulation 118:268-276.
21. van't Hof AW, Liem A, de Boer MJ, Zijlstra F (1997) Clinical value of 12-lead electrocardiogram after successful reperfusion therapy for acute myocardial infarction. Zwolle Myocardial Infarction Study Group. Lancet 350: 615-619.
22. Schröder R (2004) Prognostic impact of early ST-segment resolution in acute ST elevation myocardial infarction. Circulation  110: e506-e510.
23. De Lemos JA, Braunwald E (2001) ST segment resolution as a tool for assessing the efficacy of reperfusion therapy. J Am Coll Cardiol 38: 1283-1294.
24. Rinaldi FS, de Andrade PB, de Andrade MV, Mattos LA, Santucci EV, et al. (2013) In-hospital and Six-Month Antithrombotic Therapy after Primary Percutaneous Coronary Intervention: Analysis of Acute Coronary Care Evaluation of Practice (ACCEPT) Registry. Rev Bras Cardiol Invasiva 21: 30-35.
25. Unikas R, Budrys P (2016) Association between clinical parameters and ST-segment resolution after primary percutaneous coronary intervention in patients with acute ST-segment elevation myocardial infarction. Medicina (Kaunas) 52: 156-162.