[The use of oral and intravenous isosorbide mononitrate (5-MNi) in the acute phase of myocardial infarction].
OBJECTIVE
To evaluate the hemodynamic effects of 5-IMN in acute myocardial infarct.


METHODS
Open trial.


METHODS
Medical ICU at a general hospital.


METHODS
19 sequential patients with the diagnosis of AMI and clinical suspicion of pulmonary stasis, with a pulmonary capillary wedge pressure > 12 mmHg and a systolic blood pressure > 90 mmHg.


METHODS
No vasoactive drugs other than 5-IMN were given during the trial. The following parameters were measured at admission: heart rate (HR), mean blood pressure (BP) (indwelling arterial catheter), right atrial pressure (RAP), pulmonary arterial pressures (PAP), pulmonary capillary wedge pressure (PCWP) and cardiac output (CO). The cardiac index (CI), systolic index (SI), total peripheral resistances (TPR) and pulmonary vascular resistances (PVP) were calculated. The patients were started on 5-IMN either intravenous or oral accordingly to PCWP. The hemodynamic parameters were registered again at 30 min, 1 hour, 2, 6, 8, 24 and 48 hours and 5-IMN was stopped in all the following conditions: Severe hypoxia not improving with 5-IMN or requiring mechanical ventilation. Systolic blood pressure decreasing below 90 mmHg despite an adequate left ventricular filling pressure. Any other clinical condition forcing the use of other vasoactive drugs.


RESULTS
We discuss the hemodynamic parameters registered on admission and compare them with those obtained 48 hours after treatment with 5-IMN. The patients were divided in two groups according to PCWP: a group of 11 patients with 12 mmHg < PCWP < or = 18 mmHg who were given oral 5-IMN, and a group of 8 patients with PCWP > 18 mmHg and left ventricular failure, who were given an intravenous perfusion of 5-IMN in a dose that could keep PCWP < or = 18 mmHg. The differences between both groups are discussed. In patients with no left ventricular failure, 5-IMN decreased significantly PCWP and TPR, while increasing CO. In patients with PCWP > 18 mmHg there was also a decrease in PCWP and TPR and significant increases in both cardiac and systolic indexes. The decrease in BP was not significant in both groups.


CONCLUSIONS
5-IMN proved to be a safe drug when used during the first 48 hours of myocardial infarct even in patients with PCWP < or = 18 mmHg. It improved hemodynamics in all patients especially in those with left ventricular failure.
UCIM-Hospital de S. Francisco Xavier, Lisboa.
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Rezende
D000284:Administration, Oral; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006439:Hemodynamics / Q000187:drug effects*; D006801:Humans; D007275:Injections, Intravenous; D007548:Isosorbide Dinitrate / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology / Q000627:therapeutic use; D008297:Male; D009203:Myocardial Infarction / Q000188:drug therapy* / Q000503:physiopathology; D014665:Vasodilator Agents / Q000008:administration & dosage* / Q000494:pharmacology / Q000627:therapeutic use
D014665:Vasodilator Agents; D007548:Isosorbide Dinitrate; C030397:isosorbide-5-mononitrate
Utilização do mononitrato de isossorbido (5-MNi) oral e endovenoso na fase aguda do enfarte do miocárdio (EAM).