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Dobutamine Stress Echocardiography Like
Predictor of Improvement of Myocardial
Function Post AMI in Patients
Treated by Means of PTCA

Bujan, L; Martino, G; Weisshein, N;
Alvarez, C; Cohen, M; Hrabar, A;
Fernández, A; Bidonde, M;
Torresani, EM; Leguizamón, JH

Department of Cardiology, Sanatorio Modelo Quilmes,
Buenos Aires, Argentina

SUMMARY
Objectives: The purpose of the present study is to determine the utility of the Dobutamine Stress Echocardiography (DASE) as predictor of improvement of the segmental motility in the evolution of patients (pts) with AMI treated by means of PTCA without residual stenosis of the culprit vessel.
Methods: We included in a prospective fashion 27 pts (22 men and 5 women with mean age of 61.2 years) which were admitted with first AMI treated with successful (TIMI 3 flow with residual obstruction <30%) Primary or Rescue PTCA. The DASE was made in an average of 5.2 days from AMI, prior to discharge out of hospital ( 3 to 6 d ).Then we made Two-Dimensional Echocardiogram to the first, 3, 6 and 12 months of the follow-up. We analysed 22 pts that evidenced deterioration of the segmental motility under basal conditions. This segments were divided according to the response to the infusion of Dobutamine in viable (improvement of at least 1 point in the myocardial motility) and not viable (without improvement).
Results: We analysed 106 segments with segmental dysfunction of the basal motility,41 were viable of which 35 evidenced improvement in the follow-up and 63 of the 65 non viable stayed without variation (S:94%, E:91.3%, PPV:85%, NPV:96.9%).
Conclusions: The DASE is a test of value for prediction the improvement of the myocardial motility in pts treated with successful PTCA in AMI.

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INTRODUCTION
   Myocardial reperfusion of AMI dog save tissue, necrotic and stunned areas are the resultant of this treatment (1-2). The functional result is the same: dyssynergy. In the necrotic areas the dysfunction contractile were irreversible but in the stunned myocardium, we dog find to improvement of the contractility in the follow up (3-4).

   Different trials had show the utility of DSE (Dobutamine Stress Echocardiography) in the detection of viable myocardium post AMI, but there aren't trials who were considered this fact in the absent of residual stenosis (9-13).

   The evaluation of the ventricular function prior to hospital discharge is not the reflection of what will happen in the follow up, since this will depend of as much as necrotic myocardium and as much as stunned we find in that moment. For that reason it is necessary a method that allows to be ahead to the natural evolution and to predict the spontaneous improvement of the contractility.

OBJECTIVES
   The purpose of the present study is to determines the utility of the DSE as predictor of improvement of the segmental motility in the evolution of patients (pts) with AMI treated by means of PTCA without residual stenosis of the culprit vessel.

METHODS
   Were included in to prospective fashion 27 pts, which were admitted with first AMI treated with successful primary or rescue PTCA (Table 1).

   The DSE was made in an average of 5.2 days from AMI, prior to hospital discharge (3 to 6 days). Then we made two-dimensional echocardiogram at the first, 3, 6, and 12 months of the follow-up. Were utilized to Toshiba Sonolayer model SSH - 140 TO with 2.5 transducer. Images were digitalized with an Image Vue (Nova Microsonics 1995). Was made to baseline two - dimensional echocardiogram in the four classic views, at the end of each stage and in the recovery. Continuous electrocardiographic and echocardiographic monitoring was performed during the intravenous infusion of Dobutamine. Were started with 5µg / kg. / min., and increased to 10-20-30 and 40µg / kg. / min in each stage. Atropine were added at the end of the last stage.

   The criteria for stopping infusion include hypotension, hypertension > 200 mmHg., significant ventricular arrhythmias, angina, sub maximal heart rate reached or limitant adverse effects.

   The dyssynergic segments were divided according to the response of the infusion of Dobutamine in responders (improvement of at least 1 point in the myocardial motility) and non-responders (without improvement).

RESULTS
   We analysed 22 pts. In 106 segments with dysfunction of the basal motility, 41 were responders in which 35 shows improvement in the follow-up, and 63 of the 65 non - responders stayed without variation (S: 94%, E: 91.3%, PPV: 85%, PNV: 96.9%) Table 2.

DISCUSSION
   In the group with successful PTCA, Dobutamine infusion shows contractile reserves. It could be important in predicting the improvement of the contractility in the follow up, with high sensibility and specificity. This results have prognostic and therapeutics implication, it allows us to optimise the treatment in patients with predominant non viable segments with inhibitors of the converting that has showed its utility in prevent myocardial expansion post-AMI, and when the stunned myocardium is the predominant, we can use ß-Bloquers alone; but even keeping in mind that combination therapy is limited frequently for arterial hypotension, what forces us to diminish the dose or even to suspend some of these drugs for intolerance.

   As for the limitation of the work we should stand out the scarce number of analyzed patients, being necessary to confirm these data with a bigger population.

CONCLUSIONS
   The DSE is a test of value for prediction of the improvement of the myocardial motility in patients treated with successful PTCA in AMI.

REFERENCES

1. Verani MS, Roberts R. Preservation of cardiac function by coronary thrombolysis during acute myocardial infarction: fact or myth? J Am Coll Cardiol 1987; 10:470-6.

2. The GUSTO angiographic investigators. The effect of tissue plasminogen activator, streptokinase, or both, on coronary artery patency, ventricular function, and survival after acute myocardial infarction. N Engl J Med 1993; 329:1615-22

3. Ito H, Tomooka T, Sakai N, Higashino Y, Fujii K, Katoh O, et al. Time course of functional improvement in stunned myocardium in risk area in patients with reperfused anterior infarction. Circulation 1993;87:355-62

4. Picard HM, Wilkins GT, Ray P, Weyman AE. Long-term effects of acute thrombolytic therapy on ventricular size and function. Am Heart J 1993;126:1-10

5. Barilla F, Theorghiade M, Alam M, Khaja F, Goldstein S. Low-dose dobutamine in patients with acute myocardial infarction identifies viable but not contractile myocardium and predicts the magnitude of improvement in wall motion abnormalities in response to coronary revascularization. Am Heart J 1991;122:1522-31

6. Smart SC, Sawada S, Ryan T, Segar D, Atherton L, Berkovitz K, et al. Low-dose dobutamine echocardiography detects reversible dysfunction after thrombolytic therapy of acute myocardial infarction. Circulation 1993;88:405-15

7. Previtali M, Poli A, Lanzarini L, Fetiveau R, Mussini A, Ferrario M. Dobutamine stress echocardiography for assessment of myocardial viability and ischemia in acute myocardial infarction treated with thrombolysis. Am J Cardiol 1993;72:124G-30G

8. Salustri A, Elhendy A, Garyfallydis P, Ciavatti M, Cornel JH, Ten Cate FJ, et al. Prediction of recovery of ventricular dysfunction after first acute myocardial infarction using low-dose dobutamine echocardiography. Am J Cardiol 1994;74:853-66

9. Watada H, Ito H, Oh H, Masuyama T, Aburaya M, Hori M, et al. Dobutamine stress echocardiography predicts reversible dysfunction and quantitates the extent of irreversibly damaged myocardium after reperfusion of anterior myocardial infarction. JAm Coll Cardiol 1994;24:624-30.

 

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2nd Virtual Congress of Cardiology

Dr. Florencio Garófalo
Steering Committee
President
Dr. Raúl Bretal
Scientific Committee
President
Dr. Armando Pacher
Technical Committee - CETIFAC
President
fgaro@fac.org.ar
fgaro@satlink.com
rbretal@fac.org.ar
rbretal@netverk.com.ar
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