Comparative study between low dose dobutamine echocardiography and low dose dobutamine gated single photon emission computed tomography (gSPECT)‎ in detection of myocardial viability

الملخص EN

Background : The ldcnnlicaiion of severely dysfunctional but viable myocardium is of particular impoilance lor the selection ol patients wiili depressed left ventricular function who will benefit from coionary revascularization.

Assessment ol inotropic reserve with dobutaminc has recently been used for this purpose.

Aim oj the Study.

Comparing the accuracy ol low-dose dobutaminc (LDD) gated myocardial SPECT (gSPECI) with (he accuracy o! low dose dobutaminc cchocarciiography (DSE) and restin': perfusion single photon emission compulej tomography (SPECT) for the identification of viable myocaidmm in patients with previous myocardial infarction.

Patients and Methods-.

Resting anti low-dose dobutamme (7.5 ug / kg.niin) gated 99mTc-tetrolosmin gSPECT CTl and T2 respectively) and echocardiography (at rest and during low dose dobutaminc) (R and DSE) and resting post-revascularization echocardiography (PRecho) (3 months later) were prospectively studied in 33 patients with previous myocardial infarction and severely depressed regional function.

Revascularization had been done either by CABC or PTCA lor all patients.

Nitroglycerine had been administered 15 mm for all patients before 99mTc-ici.-olosmin 12 Wall motion assessment was done using 4 point scorc with I normal and 4 dyskinctic and viable tissue was diagnosed by presence ol contractile response fCD) tiurina LDD infusion in both echocardiography and gated SPECT using 17 segment model.

Viability was defined in pc, fusion study by a i cl at) vc uptake 50% of the maximum uptake.

Viability in.

gSPECT depended upon both end-cliasiolic

Results Out ol the 561 myocardial segments resting-ccho (R) revealed 367 segments with normal wall motion (NWMt, 109 .hypokinetic- with CD in 83.

52 akmclie with CD in 24.

33 dysk.net,c with CD in 3.

Post-revascularization ccho.

revealed 476 segments with NWM.

26 hypo, 29 ak , and 30 dyskinetic.

Concerning gSPECT.

out ol the 194 segments with abnormal wall motion.

Tl and T2 revealed 16 and 23 with normal uptake.

1 I and 18 with complete reversibil.lv.

M) and 96 with partial reversibility with overall detection of vubilily in 44.8% and 70.6% respectively.

Degree of matching between DSE and Tl and T2 was found to he 70.6% and 80.9% respectively.

Compared lo PR echo.'", degree of matching was 69.6%, 92.3% and 85.6% lor Tl.

T2 and DSE respectively Conclusion.

Pharmacological enhancement loi delecting viability cither bv a SPECT or echocardiography.

Combined Perfusion and Umci.onal nssessm - u compensates lor lower sensmviiv of Tc-tetrofosmin.