Relationship between contractile reserve, Tl-201 uptake, and collateral angiographic circulation in collateral-dependent myocardium: implications regarding the evaluation of myocardial viability.
BACKGROUND
The aim of this study was to compare collateral angiographic circulation (CC), thallium 201 single photon emission computed tomography (SPECT), low-dose dobutamine echocardiography (LDDE), and their combination in identifying viable myocardium beyond a chronic occlusion.


RESULTS
We studied 33 consecutive patients with a chronic occluded coronary artery and regional ventricular dysfunction who underwent dobutamine infusion (5-10 microg x kg(-1) x min(-1)), Tl-201 SPECT, and coronary revascularization (15 patients underwent coronary artery bypass grafting and 18 patients percutaneous transluminal coronary angioplasty). Echocardiography and Tl-201 SPECT at rest were repeated 90 +/- 48 days after revascularization. For viability assessment, Tl-201 SPECT showed the best sensitivity and accuracy (77% and 72%, respectively) compared with LDDE (64% and 63%, respectively) and CC (74% and 55%, P < .05 vs Tl-201 SPECT). Specificity was significantly better for both Tl-201 SPECT (65%) and LDDE (62%) compared with collateral circulation (27%, P < .001 vs Tl-201 SPECT and LDDE). Furthermore, combined Tl-201 SPECT and LDDE data improved specificity (from 88% to 92%) and positive predictive power (from 75% to 78%) but not global accuracy. A direct relationship between the number of viable segments and global functional recovery after revascularization was found only in the case of Tl-201 SPECT (r = 0.48, P = .04).


CONCLUSIONS
This study demonstrates that CC has a very low specificity in the evaluation of viability in collateral-dependent myocardium and that LDDE has a very low sensitivity, whereas Tl-201 SPECT is the most reliable method, particularly in akinetic segments, and optimally identifies patients who will mostly benefit from revascularization in terms of ventricular functional improvement. No additional advantages in terms of accuracy were found when Tl-201 SPECT and LDDE data were combined.
Piscione
Federico
F
Division of Cardiology, Federico II University, Naples, Italy. piscione@unina.it
De Luca
Giuseppe
G
Perrone-Filardi
Pasquale
P
Prastaro
Mariella
M
Pace
Leonardo
L
Galasso
Gennaro
G
Marrazzo
Gemma
G
Salvatore
Marco
M
Chiariello
Massimo
M
D000368:Aged; D015906:Angioplasty, Balloon, Coronary; D003097:Collateral Circulation / Q000502:physiology*; D017023:Coronary Angiography; D001026:Coronary Artery Bypass; D003326:Coronary Circulation / Q000502:physiology; D003327:Coronary Disease / Q000175:diagnosis* / Q000503:physiopathology / Q000628:therapy; D025401:Echocardiography, Stress; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction / Q000502:physiology; D012680:Sensitivity and Specificity; D013794:Thallium Radioisotopes / Q000378:metabolism; D015899:Tomography, Emission-Computed, Single-Photon; D018754:Ventricular Dysfunction / Q000175:diagnosis* / Q000503:physiopathology / Q000628:therapy
D013794:Thallium Radioisotopes