| Objectives: ST-segment elevation myocardial infarction (STEMI) is themost devastating ischemia heart disease which affects the cardiac metabolism,structure and function. Early and successful myocardial reperfusion is the mosteffective strategy for impending acute myocardial infarction by the use ofthrombolytic therapy, and primary percutaneous coronary intervention (PPCI)which can reduce myocardial infarction size and improving the clinicaloutcome. In spite of successfully repatency of the infarct related artery (IRA)by urgent PCI, many patients with acute STEMI encountered slow-reflow orno-reflow phenomenon refers to the impedance of microvascular blood flowduring opening of the IRA, as well as develop symptomatic heart failure,malignant arrhythmia within the first days after admission due todysfunctional viable tissue or myocardial cell necrosis. This phenomenon,termed myocardial ischemia reperfusion injury, can paradoxically reduce thebeneficial effects of myocardial reperfusion. Accumulating researchesindicated that post-conditioning could decrease myocardial reperfusion injurythrough a series of protective mechanisms. Recombinant human B-typenatriuretic peptide has pharmacological activation of particulate guanylatecyclase (pGc), induced cardio-protection by activating cGMP-PKG signalpathway. In this pilot prospective trial, we investigated whether theadministration of exogenous BNP before the time of primary percutaneouscoronary intervention could further limit the infract size in patients with acutemyocardial infarction based on the early researches.Methods: A total of93patients were submitted to primary PCI forongoing acute anterior wall ST-elevation myocardial infarction (STEMI), from January2011to December2013in our hospital contributed to this study. Theywere randomly assigned to the either a recombinant human B-type natriureticpeptide group (rhBNP group n=48) or a nitroglycerin group (Nit group n=45). Apreoperative evaluation was made in all patients. The basic clinicalcharacteristics of patients in each group, including age, gender distribution,risk factors (hypertension, diabetes, dyslipidemia, stroke, smoking history),cardiac function, serum BNP level and clinical presentations were recorded. Adose of300mg aspirin,300mg clopidogrel and40mg atorvastatin were given.Patients in rhBNP group were administrated rhBNP (1.5μg/kg bolusintravenous injection followed by0.0075-0.030μg/kg/min up to120hours)before and after the immediate onset of myocardial reperfusion, andnitroglycerin was administrated from10μg/min to100μg/min according to thelevel of blood pressure in Nit group. Primary PCI was performed in bothgroups using post-conditioning technique. Aspirin100mg/d, clopidogrel75mg/d and statins were given by oral, as well as ACEI or ARB, and/orβ-blocker, and/or nitrates. TIMI grade, CTFC, myocardial blush grade werecompared at the very time of IRA opening. The myocardial enzymes weredynamically observed. LVEDV, LVESV, LVEF, E/A, E/e’ and WMSI wererecorded by echocardiography at1week after PCI in order to assess the wallmotion and the recovery of ventricular function, and serum BNP level duringhospitalization were compared between the two groups too. Besides, the majoradverse cardiac events (MACEs), including cardiac deaths, recurrent nonfatalmyocardial infarction, malignant arrhythmias and target vesselrevascularization were observed in3months follow-up.Results: The two treatment groups were well balanced with regard to allbaseline characteristics, initial treatments, and procedures. Although there wereno significant differences between the two groups, the percentage of TIMIgrade3achieved in IRA after PCI (95.8%vs.86.6%，P=0.16), as well as thepercentage of myocardial blush grade3in rhBNP group was higher than thatin Nit group (72.9%vs.62.2%，P=0.5). The CFTC, an indicator of quantitativeanalysis, was notably decreased in rhBNP group (20.96±8.66vs.28.24±14.79, P=0.005). The release of creatine kinase MB isoenzyme (CK-MB), and thearea under the curve of CK-MB were significantly reduced approximately27%in rhBNP group compared with Nit group (3249.8±1101.6vs.4474.2±1661.8，P=0.01), the area under the curve of cTnI decreased about18%contemporary(367.04±94.26vs.445.14±109.99，P=0.021). As compared to Nit group,although there were no significant differences，the left ventricular ejectionfraction (LVEF) and E/A were higher, and LVEDV and LVESV were lower inrhBNP group (all P＞0.05). However, E/e’ and WSMI were significantlyreduced in rhBNP group (11.95±3.31vs.14.60±4.09, P=0.03),(1.74±0.17vs.2.40±0.554, P<0.001). The serum BNP level was reduced observably inrhBNP group7days after the onset than that in Nit group (68.34±37.75vs.229.44±134.40，P<0.001). After treatment the serum BNP level in rhBNPgroup was much lower (247.68±141.24vs.68.34±37.75，P<0.001), and therewas no significant difference in Nit group after treatment (260.21±142.84vs.229.44±134.40，P=0.55). As compared to Nit group at3-month of follow up,the incidence of malignant arrhythmia was not found statistically significance,but it was slight lower in rhBNP group (P=0.194). One patient was dead in Nitgroup，none of the patients in each group occurred recurrent myocardialinfarction, and repeated revascularization during3-month follow-up.Conclusion: Administration of exogenous B-type natriuretic peptide atearly reperfusion improves myocardial perfusion, affords more significantinfarct size reduction, ameliorates cardiac function and restrains leftventricular remodeling in STEMI patients undergoing primary PCI withpost-conditioning procedure. |
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