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Comparison of low-dose dobutamine ventriculography with low-dose dobutamine echocardiography for predicting regional improvement in left ventricular function after coronary artery bypass grafting
Comparison of Low-Dose Dobutamine Ventriculography With Low-Dose Dobutamine Echocardiography for Predicting Regional Improvement in Left Ventricular Function After Coronary Artery Bypass Grafting Laura Dalla Vecchia, MD, Tania Storti, MD, Chiara Cogliati, MD, Stefano Guzzetti, MD, Paolo Danna, MD, Roberto Scrofani, MD, Pietro Di Biasi, MD, and Alberto Malliani, MD The demonstration of a contractile reserve during lowdose dobutamine echocardiography (LDDE) identifies viable myocardium and predicts recovery of left ventricular (LV) function after myocardial revascularization in patients with chronic coronary artery disease. However, a technically difficult transthoracic visualization may limit the use of LDDE, thus requiring an alternative diagnostic procedure. The present study compares LDDE with low-dose dobutamine ventriculography (LDDV) in predicting an improvement in regional LV function after surgical revascularization. We studied 18 patients with coronary artery disease and LV dysfunction who were to undergo coronary artery bypass grafting. Preoperatively, all patients were evaluated for the presence of viable myocardium using LDDE and LDDV. Follow-up echocardiography at rest and left ventriculography were performed 4 months after successful revascularization to
assess recovery of LV function. The sensitivity and specificity of LDDE to identify dysfunctional segments capable of recovering function were 63% and 71%, respectively, with a diagnostic accuracy of 68%. The sensitivity, specificity, and diagnostic accuracy of LDDE improved to 81%, 72%, and 76% when patients with optimal transthoracic evaluation were selected, whereas they were 30%, 77%, and 57%, respectively, in those who underwent suboptimal evaluation. The sensitivity, specificity, and diagnostic accuracy of LDDV were 66%, 75%, and 71%, respectively, with no difference in subgroups of patients. This study demonstrates that LDDV can be considered a useful technique for identifying the presence of myocardial viability and may provide an advantage over LDDE in patients with suboptimal echocardiographic visualization. 䊚2000 by Excerpta Medica, Inc. (Am J Cardiol 2000;86:371–374)
ecause all patients with coronary artery disease and possible indication for revascularization unB dergo cardiac catheterization with coronary and left
METHODS
ventricular (LV) angiography, demonstrating some contractile reserve by dobutamine administration during LV angiography may provide a tool to select patients with viable myocardium.1 Thus, in patients with limited echocardiographic visualization, left ventriculography during inotropic stimulation could be used to address surgical indications. Recently, this application has been proposed for patients undergoing percutaneous transluminal coronary angioplasty.2 The present study compares the predictive value of lowdose dobutamine echocardiography (LDDE) with that of low-dose dobutamine left ventriculography (LDDV) in identifying reversible regional LV dysfunction in patients with chronic coronary artery disease undergoing surgical revascularization. From Medicina Interna II, Cardiologia, and Cardiochirurgia, Ospedale L. Sacco, Universita` di Milano, Milan, Italy. Manuscript received November 23, 1999; revised manuscript received and accepted February 23, 2000. Address for reprints: Laura Dalla Vecchia, MD, Medicina Interna II, Ospedale L. Sacco, Via GB Grassi 74, 20157 Milan, Italy. E-mail: [email protected]. ©2000 by Excerpta Medica, Inc. All rights reserved. The American Journal of Cardiology Vol. 86 August 15, 2000
Study group: We studied 18 consecutive patients (16 men and 2 women; mean patient age 58 ⫾ 2 years [range 51 to 72]) with chronic coronary artery disease who were referred to our hospital for coronary artery bypass grafting. The study enrollment criteria included the presence of ⱖ1 akinetic or hypokinetic segment on preoperative resting echocardiography (16-segment LV model), and absence of recent episodes of unstable angina and of significant (⬎50%) left main stenosis. Patients with hemodynamically significant valvular disease, atrial fibrillation, and acute congestive heart failure were also excluded from the study. All patients had a history of previous myocardial infarction (⬎3 months old) and were symptomatic for angina pectoris; 6 also had dyspnea on effort. Significant coronary artery disease was defined as a ⬎50% reduction in luminal diameter: 11 patients had 3-vessel disease, 7 had 2-vessel disease. No patient had undergone previous surgery. All patients were taking angiotensin-converting enzyme inhibitors, aspirin, and nitrates. Mean echocardiographic LV ejection fraction was 37 ⫾ 3% (range 15% to 50%), whereas mean angiographic LV ejection fraction was 35 ⫾ 4% (range 20% to 60%). 0002-9149/00/$–see front matter PII S0002-9149(00)00948-6
371
akinesia, and 5 dyskinesia. Improvement of contractile function in a segment was defined as an increase in systolic thickening and wall motion of that segment during either stage of the dobutamine infusion by ⱖ1 grade compared with the baseline score. Angiographic studies and analysis: Angiographic views were
obtained using a Philips Angio Diagnost 5 System (Eindhoven, The Netherlands). Coronary artery narrowing was visually measured as percent diameter stenosis. LV angiography was performed by power injection of 40 ml of Ultravist 370 (Schering, Milan, Italy) at 12 to 15 ml/s. Global and regional LV wall moFIGURE 1. Pie charts showing the effects of low-dose dobutamine infusion and of corotion were evaluated in the 30° nary revascularization on regional systolic function assessed by transthoracic echocardiography in the entire group of patients. right anterior oblique projection in basal conditions and at the end of a 10-minute infusion of dobutStudy protocol: Preoperatively (4 ⫾ 2 days before amine (5 minutes at a dose of 5 g/kg/min, and 5 surgery), all patients were evaluated for presence of minutes at a dose of 10 g/kg/min). Control postopviable myocardium using LDDE and LDDV. Fol- erative left ventriculography was performed in basal low-up echocardiography at rest and left ventriculog- conditions. raphy were performed 4 months after successful reComputer-assisted evaluation of wall motion4 provascularization to assess the recovery of LV function. vided quantitative indexes of regional and global LV The study protocol was approved by our hospital kinesis; end-diastolic and end-systolic silhouettes committee on human research, and all patients gave were divided into 5 segments and 20 (5 ⫻ 4) subsegwritten informed consent. ments: the systolic percentage reduction of each area Echocardiographic studies and analysis: The dobut- was obtained to draw a contraction curve. A specific amine test was performed using a standard protocol: algorithm then computed a score for each subsegment With the patient lying in the left lateral recumbent (0 ⫽ normal kinesis, 1 ⫽ mild hypokinesia, 2 ⫽ position, resting 2-dimensional transthoracic echocar- moderate hypokinesia, 3 ⫽ severe hypokinesia, 4 ⫽ diographic and Doppler assessment was first obtained. akinesia, and 5 ⫽ dyskinesia). Improvement in segImaging during intravenous infusion of dobutamine at mental contractile function was defined as a change a dose of 5 and 10 g/kg/min was then performed for ⱖ15% compared with baseline. 5 minutes at each dose. Images were obtained from Statistical analysis: Results are expressed as the standard parasternal and apical views. All studies mean ⫾ SE. Pre- and postoperative changes in echowere performed with a Hewlett-Packard Sonos 1000 cardiographic and angiographic ejection fraction were ultrasound system (Andover, Massachusetts) equip- analyzed by paired Student’s t test. The chi-square test ped with a 2.5-MHz transducer and were recorded on was used to calculate independence of variables. SenVHS tape. Control postoperative echocardiographic sitivity, specificity, and accuracy were calculated by studies followed the same protocol described for the applying standard formulas. Statistical significance rest studies. was set at a p value of ⬍0.01. Echocardiographic images displayed in a quad screen were analyzed off-line from the videotape play- RESULTS back by 2 experienced observers unaware of the anEchocardiographic and angiographic studies were giographic results and the clinical details. Identical performed without major complications. Isolated suLV segments at rest and during administration of praventricular or ventricular premature complexes ocdobutamine were analyzed for regional wall motion curred in 3 patients at peak dobutamine infusion durusing a standard 16-segment model following the rec- ing LDDE and in 2 patients during LDDV; in one case ommendations of the American Society of Echocar- LDDV was interrupted after 9 minutes because of diography.3 Differences in interpretation were re- ventricular bigeminism. All patients underwent successful revascularizasolved by consensus. Visual assessment of wall motion and systolic tion: 7 patients received a triple bypass, 7 a double thickening of the analyzed segments were graded us- bypass, and 4 a single bypass. The left internal maming a scoring system in which 1 indicated normal mary artery was used in all patients; for the remaining kinesis, 2 mild hypokinesia, 3 severe hypokinesia, 4 anastomoses, an autologous saphenous vein was used. 372 THE AMERICAN JOURNAL OF CARDIOLOGY姞
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FIGURE 2. Pie charts showing the effects of low-dose dobutamine infusion and of coronary revascularization on regional systolic function assessed by transthoracic echocardiography (TTE) in patients with optimal (left pies) and suboptimal (right pies) TTE.
One patient was withdrawn from the study because of perioperative myocardial infarction. Echocardiographic results: We found that 182 segments of 272 (67%) available for analysis had wall motion abnormalities during basal conditions. During dobutamine infusion none of the dysfunctional segments manifested further deterioration of function, whereas 79 (43%) showed a functional improvement. The remaining 103 dysfunctional segments (57%) did not show functional changes during dobutamine infusion (Figure 1a). LV ejection fraction improved from 37 ⫾ 3% at baseline to 49 ⫾ 3% at peak infusion (p ⬍0.01). The postoperative echocardiographic studies demonstrated regional and global improvement in LV function: kinesis improved in 67 segments (37%) and LV ejection fraction increased from the preoperative value of 37 ⫾ 3% to 43 ⫾ 3% (p ⬍0.01). Of 79 segments with improved kinesis during LDDE, 49 (62%) were found improved on the echocardiogram obtained after revascularization (true positive) (Figure 1b). Of 103 segments with unchanged kinesis, 74 segments (72%) also remained unchanged after surgery (true negative) (Figure 1c). The sensitivity and specificity of LDDE to identify dysfunctional segments capable of recovering function were therefore 63% and 71%, respectively. Diagnostic accuracy for predicting functional improvement of dysfunctional segments after revascularization was 68%. Because these percentages were lower than those found in other studies,5–7 we analyzed data after identification of patients with optimal and suboptimal transthoracic echocardiographic evaluation. Echocardiographic examinations in which the inter- and intraobserver concordances of resting wall motion analysis and wall motion response during LDDE were ⬍80% were considered suboptimally evaluated. In patients (n ⫽ 10) characterized by an optimal transthoracic visualization of the left ventricle, 128 of 160 segments (80%) had depressed function. During LDDE, kinesis improved in 66 segments (52%),
whereas the remaining 62 (48%) did not show functional change (Figure 2a). Of 66 segments with improved kinesis during LDDE, 46 (70%) exhibited an improvement after surgery (true positive), whereas 51 of 62 segments (82%) with unchanged kinesis during LDDE also remained unchanged postoperatively (true negative) (Figure 2b). Thus, in patients with optimal transthoracic echocardiographic visualization, sensitivity, specificity, and diagnostic accuracy of LDEE became 81%, 72%, and 76%, respectively. In patients with limited transthoracic visualization, only 54 of 112 segments (48%) were found to be hypokinetic (Figure 2c). Of 14 segments (32%) with improved kinesis during LDDE, 7 (50%) improved after surgery (true positive), whereas 24 of 40 segments (60%) with no improvement during LDDE also remained unchanged postoperatively (true negative) (Figure 2). Sensitivity, specificity, and diagnostic accuracy were therefore 30%, 77%, and 57%, respectively. Angiographic results: LV angiography in basal conditions disclosed 205 dysfunctional subsegments (64%) (defined as segments with an ejection fraction ⬍50%) of 320 segments available for analysis. During dobutamine infusion, none of these segments manifested further deterioration of function, whereas 96 (47%) showed a functional improvement. The remaining 109 dysfunctional segments (53%) did not show functional changes during dobutamine (Figure 3a). LV ejection fraction increased from 35 ⫾ 4% at baseline to 44 ⫾ 4% at peak infusion (p ⬍0.01). The postoperative angiographic studies demonstrated regional and global improvement in LV function; kinesis improved in 101 subsegments (49%), and LV ejection fraction increased from the preoperative value of 35 ⫾ 4% to 45 ⫾ 3% (p ⬍0.01). Of 96 segments with improved kinesis during LDDV, 56 (58%) were found improved at postoperative ventricular angiography (true positive) (Figure 3b); 90 of 109 segments (83%) with unchanged kine-
CORONARY ARTERY DISEASE/DOBUTAMINE VENTRICULOGRAPHY DETECTS MYOCARDIAL VIABILITY
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an underestimation of segmental hypokinesia in basal condition, reducing LDDE sensitivity. In an attempt to overcome this fairly frequent clinical obstacle, we tested the application of dobutamine infusion during routine LV angiography. Considering the total group of patients, we demonstrated that LDDV is as sensitive, specific, and accurate as LDDE. In addition, LDDV is not influenced by thoracic features of the patients. 1. Gould KL. Myocardial viability: what does it
mean and how to measure? Circulation 1991;83: 333–335. 2. Sanchis J, Bodi V, Insa L, Go´mez-Aldaravi R, Berenguer A, Lo´pez-Lereu MP, Chorro FJ, Lo´pezFIGURE 3. Pie charts showing the effects of low-dose dobutamine infusion and of coroMerino V. Low-dose dobutamine testing using nary revascularization on regional systolic function assessed by left ventriculography. contrast left ventriculography in the same session as coronary angiography predicts the improvement of left ventricular function after coronary angioplasty in postinfarction patients. Am J Cardiol 1999;83:15–20. sis during LDDV also remained unchanged after sur- 3. Schiller NB, Shaha PM, Crawford M, De Maria A, Devereaux R, Feigenbaum H, Gutgesell H, Reichek N, Sahn D, Schnittger I, Silverman NH, Taijik AJ. gery (true negative) (Figure 3c). Recommendations for quantification of the left ventricle by two-dimensional The sensitivity and specificity of LDDV to identify echocardiography. J Am Soc Echocardiogr 1989;2:358 –367. dysfunctional segments capable of functional recovery 4. Bozzi G, Verna E, Skinner JM, Dwyer ML, Castelfranco M. Quantitative regional contraction analysis of cineventriculography: reporting, filling and rewere therefore 66% and 75%, respectively. Diagnostic trieval function using a personal computer. Cathet Cardiovasc Diagn 1989;2: accuracy for predicting functional improvement of 358 –367. 5. Cigarroa CG, de Filippi CR, Brickner ME, Alvarez LG, Wait MA, Grayburn dysfunctional segments after revascularization was PA. Dobutamine stress echocardiography identifies hibernating myocardium and 71%. Such values did not differ for subgroups of predicts recovery of left ventricular function after coronary revascularization. Circulation 1993;88:430 – 436. patients. 6. Perrone-Filardi P, Pace L, Prastaro M, Piscione F, Betocchi S, Squame F, Vezzuto P, Soricelli A, Indolfi C, Salvatore M, Chiariello M. Dobutamine echocardiography predicts improvement of hypoperfused dysfunctional myocardium after revascularization in patients with coronary artery disease. Circulation 1995;91:2556 –2565. 7. Arnese M, Cornel JH, Salustri A, Maat APWM, Elhendy A, Reijs AEM, Ten To our knowledge this is the first report that dem- Cate FJ, Keane D, Balk AHMM, Roelandt JRTC, Fioretti PM. Prediction of improvement of regional left ventricular function after surgical revascularization. onstrates that LDDV is able to identify hypoperfused A comparison of low-dose dobutamine echocardiography with 201Tl single emisand dysfunctional myocardium capable of recovering sion computed tomography. Circulation 1995;91:2748 –2752. 8. Afridi I, Grayburn PA, Panza JA, Oh JK, Zoghbi WA, Marwick TH. Myofunction after surgical revascularization. In recent cardial viability during dobutamine echocardiography predicts survival in payears, numbers of diagnostic techniques have been tients with coronary artery disease and severe ventricular systolic dysfunction. Coll Cardiol 1998;32:921–926. proposed to determine the presence and extent of J9.Am Kauffman GJ, Boyne TS, Denny DW, Smith WH, Beller GA. Comparison of 5–12 myocardial viability in ischemic cardiomyopathy rest thallium-201 imaging and rest technetium-99m sestamibi imaging for assessto identify patients who might benefit from coronary ment of myocardial viability in patients with coronary artery disease and severe left ventricular dysfunction. J Am Coll Cardiol 1996;27:1592–1597. revascularization as an alternative to medical therapy 10. Auerbach MA, Schoder H, Hoh C, Gambhir SS, Yaghoubi S, Sayre JW, 1,13,14 LDDE has been ex- Silverman D, Phelps ME, Schelbert HR, Czernin J. Prevalence of myocardial or cardiac transplantation. as detected by positron emission tomography in patients with ischemic tensively used for its high diagnostic accuracy, for its viability cardiomyopathy. Circulation 1999;99:2921–2926. 5,6,8 In clinical practice 11. Zoghbi W, Barash E. Dobutamine MRI: a serious contender in pharmacolow cost, and noninvasiveness. the use of transthoracic echocardiography can be lim- logical stress imaging. Circulation 1999;99:730 –732. 12. Baer FM, Voth E, Deutsch H, Schneider CA, Schicha H, Sechtem U. ited by the impossibility to achieve an adequate visu- Assessment of viable myocardium by dobutamine-transesophageal-echocardiogalization of cardiac chambers. raphy (TEE) and comparison with FDG-PET. J Am Coll Cardiol 1994;24:343– In our study, LDDE has indeed been found less 353. 13. Elefteriades JA, Tolis G, Levi E, Mills LK, Zaret BL. Coronary artery by pass sensitive and less accurate in predicting LV functional grafting in severe left ventricular dysfunction: excellent survival with improved recovery after revascularization in patients with sub- ejection fraction and functional state. J Am Coll Cardiol 1993;22:1411–1417. 14. Pasquet A, Robert A, D’Hondt AM, Dion R, Melin J, Vanoverschelde JLJ. optimal transthoracic evaluation. In such patients, the Prognostic value of myocardial ischemia and viability in patients with chronic left lack of adequate endocardial detection has determined ventricular ischemic dysfunction. Circulation 1999;100:141–148.
DISCUSSION
374 THE AMERICAN JOURNAL OF CARDIOLOGY姞
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assess recovery of LV function. The sensitivity and specificity of LDDE to identify dysfunctional segments capable of recovering function were 63% and 71%, respectively, with a diagnostic accuracy of 68%. The sensitivity, specificity, and diagnostic accuracy of LDDE improved to 81%, 72%, and 76% when patients with optimal transthoracic evaluation were selected, whereas they were 30%, 77%, and 57%, respectively, in those who underwent suboptimal evaluation. The sensitivity, specificity, and diagnostic accuracy of LDDV were 66%, 75%, and 71%, respectively, with no difference in subgroups of patients. This study demonstrates that LDDV can be considered a useful technique for identifying the presence of myocardial viability and may provide an advantage over LDDE in patients with suboptimal echocardiographic visualization. 䊚2000 by Excerpta Medica, Inc. (Am J Cardiol 2000;86:371–374)
ecause all patients with coronary artery disease and possible indication for revascularization unB dergo cardiac catheterization with coronary and left
METHODS
ventricular (LV) angiography, demonstrating some contractile reserve by dobutamine administration during LV angiography may provide a tool to select patients with viable myocardium.1 Thus, in patients with limited echocardiographic visualization, left ventriculography during inotropic stimulation could be used to address surgical indications. Recently, this application has been proposed for patients undergoing percutaneous transluminal coronary angioplasty.2 The present study compares the predictive value of lowdose dobutamine echocardiography (LDDE) with that of low-dose dobutamine left ventriculography (LDDV) in identifying reversible regional LV dysfunction in patients with chronic coronary artery disease undergoing surgical revascularization. From Medicina Interna II, Cardiologia, and Cardiochirurgia, Ospedale L. Sacco, Universita` di Milano, Milan, Italy. Manuscript received November 23, 1999; revised manuscript received and accepted February 23, 2000. Address for reprints: Laura Dalla Vecchia, MD, Medicina Interna II, Ospedale L. Sacco, Via GB Grassi 74, 20157 Milan, Italy. E-mail: [email protected]. ©2000 by Excerpta Medica, Inc. All rights reserved. The American Journal of Cardiology Vol. 86 August 15, 2000
Study group: We studied 18 consecutive patients (16 men and 2 women; mean patient age 58 ⫾ 2 years [range 51 to 72]) with chronic coronary artery disease who were referred to our hospital for coronary artery bypass grafting. The study enrollment criteria included the presence of ⱖ1 akinetic or hypokinetic segment on preoperative resting echocardiography (16-segment LV model), and absence of recent episodes of unstable angina and of significant (⬎50%) left main stenosis. Patients with hemodynamically significant valvular disease, atrial fibrillation, and acute congestive heart failure were also excluded from the study. All patients had a history of previous myocardial infarction (⬎3 months old) and were symptomatic for angina pectoris; 6 also had dyspnea on effort. Significant coronary artery disease was defined as a ⬎50% reduction in luminal diameter: 11 patients had 3-vessel disease, 7 had 2-vessel disease. No patient had undergone previous surgery. All patients were taking angiotensin-converting enzyme inhibitors, aspirin, and nitrates. Mean echocardiographic LV ejection fraction was 37 ⫾ 3% (range 15% to 50%), whereas mean angiographic LV ejection fraction was 35 ⫾ 4% (range 20% to 60%). 0002-9149/00/$–see front matter PII S0002-9149(00)00948-6
371
akinesia, and 5 dyskinesia. Improvement of contractile function in a segment was defined as an increase in systolic thickening and wall motion of that segment during either stage of the dobutamine infusion by ⱖ1 grade compared with the baseline score. Angiographic studies and analysis: Angiographic views were
obtained using a Philips Angio Diagnost 5 System (Eindhoven, The Netherlands). Coronary artery narrowing was visually measured as percent diameter stenosis. LV angiography was performed by power injection of 40 ml of Ultravist 370 (Schering, Milan, Italy) at 12 to 15 ml/s. Global and regional LV wall moFIGURE 1. Pie charts showing the effects of low-dose dobutamine infusion and of corotion were evaluated in the 30° nary revascularization on regional systolic function assessed by transthoracic echocardiography in the entire group of patients. right anterior oblique projection in basal conditions and at the end of a 10-minute infusion of dobutStudy protocol: Preoperatively (4 ⫾ 2 days before amine (5 minutes at a dose of 5 g/kg/min, and 5 surgery), all patients were evaluated for presence of minutes at a dose of 10 g/kg/min). Control postopviable myocardium using LDDE and LDDV. Fol- erative left ventriculography was performed in basal low-up echocardiography at rest and left ventriculog- conditions. raphy were performed 4 months after successful reComputer-assisted evaluation of wall motion4 provascularization to assess the recovery of LV function. vided quantitative indexes of regional and global LV The study protocol was approved by our hospital kinesis; end-diastolic and end-systolic silhouettes committee on human research, and all patients gave were divided into 5 segments and 20 (5 ⫻ 4) subsegwritten informed consent. ments: the systolic percentage reduction of each area Echocardiographic studies and analysis: The dobut- was obtained to draw a contraction curve. A specific amine test was performed using a standard protocol: algorithm then computed a score for each subsegment With the patient lying in the left lateral recumbent (0 ⫽ normal kinesis, 1 ⫽ mild hypokinesia, 2 ⫽ position, resting 2-dimensional transthoracic echocar- moderate hypokinesia, 3 ⫽ severe hypokinesia, 4 ⫽ diographic and Doppler assessment was first obtained. akinesia, and 5 ⫽ dyskinesia). Improvement in segImaging during intravenous infusion of dobutamine at mental contractile function was defined as a change a dose of 5 and 10 g/kg/min was then performed for ⱖ15% compared with baseline. 5 minutes at each dose. Images were obtained from Statistical analysis: Results are expressed as the standard parasternal and apical views. All studies mean ⫾ SE. Pre- and postoperative changes in echowere performed with a Hewlett-Packard Sonos 1000 cardiographic and angiographic ejection fraction were ultrasound system (Andover, Massachusetts) equip- analyzed by paired Student’s t test. The chi-square test ped with a 2.5-MHz transducer and were recorded on was used to calculate independence of variables. SenVHS tape. Control postoperative echocardiographic sitivity, specificity, and accuracy were calculated by studies followed the same protocol described for the applying standard formulas. Statistical significance rest studies. was set at a p value of ⬍0.01. Echocardiographic images displayed in a quad screen were analyzed off-line from the videotape play- RESULTS back by 2 experienced observers unaware of the anEchocardiographic and angiographic studies were giographic results and the clinical details. Identical performed without major complications. Isolated suLV segments at rest and during administration of praventricular or ventricular premature complexes ocdobutamine were analyzed for regional wall motion curred in 3 patients at peak dobutamine infusion durusing a standard 16-segment model following the rec- ing LDDE and in 2 patients during LDDV; in one case ommendations of the American Society of Echocar- LDDV was interrupted after 9 minutes because of diography.3 Differences in interpretation were re- ventricular bigeminism. All patients underwent successful revascularizasolved by consensus. Visual assessment of wall motion and systolic tion: 7 patients received a triple bypass, 7 a double thickening of the analyzed segments were graded us- bypass, and 4 a single bypass. The left internal maming a scoring system in which 1 indicated normal mary artery was used in all patients; for the remaining kinesis, 2 mild hypokinesia, 3 severe hypokinesia, 4 anastomoses, an autologous saphenous vein was used. 372 THE AMERICAN JOURNAL OF CARDIOLOGY姞
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AUGUST 15, 2000
FIGURE 2. Pie charts showing the effects of low-dose dobutamine infusion and of coronary revascularization on regional systolic function assessed by transthoracic echocardiography (TTE) in patients with optimal (left pies) and suboptimal (right pies) TTE.
One patient was withdrawn from the study because of perioperative myocardial infarction. Echocardiographic results: We found that 182 segments of 272 (67%) available for analysis had wall motion abnormalities during basal conditions. During dobutamine infusion none of the dysfunctional segments manifested further deterioration of function, whereas 79 (43%) showed a functional improvement. The remaining 103 dysfunctional segments (57%) did not show functional changes during dobutamine infusion (Figure 1a). LV ejection fraction improved from 37 ⫾ 3% at baseline to 49 ⫾ 3% at peak infusion (p ⬍0.01). The postoperative echocardiographic studies demonstrated regional and global improvement in LV function: kinesis improved in 67 segments (37%) and LV ejection fraction increased from the preoperative value of 37 ⫾ 3% to 43 ⫾ 3% (p ⬍0.01). Of 79 segments with improved kinesis during LDDE, 49 (62%) were found improved on the echocardiogram obtained after revascularization (true positive) (Figure 1b). Of 103 segments with unchanged kinesis, 74 segments (72%) also remained unchanged after surgery (true negative) (Figure 1c). The sensitivity and specificity of LDDE to identify dysfunctional segments capable of recovering function were therefore 63% and 71%, respectively. Diagnostic accuracy for predicting functional improvement of dysfunctional segments after revascularization was 68%. Because these percentages were lower than those found in other studies,5–7 we analyzed data after identification of patients with optimal and suboptimal transthoracic echocardiographic evaluation. Echocardiographic examinations in which the inter- and intraobserver concordances of resting wall motion analysis and wall motion response during LDDE were ⬍80% were considered suboptimally evaluated. In patients (n ⫽ 10) characterized by an optimal transthoracic visualization of the left ventricle, 128 of 160 segments (80%) had depressed function. During LDDE, kinesis improved in 66 segments (52%),
whereas the remaining 62 (48%) did not show functional change (Figure 2a). Of 66 segments with improved kinesis during LDDE, 46 (70%) exhibited an improvement after surgery (true positive), whereas 51 of 62 segments (82%) with unchanged kinesis during LDDE also remained unchanged postoperatively (true negative) (Figure 2b). Thus, in patients with optimal transthoracic echocardiographic visualization, sensitivity, specificity, and diagnostic accuracy of LDEE became 81%, 72%, and 76%, respectively. In patients with limited transthoracic visualization, only 54 of 112 segments (48%) were found to be hypokinetic (Figure 2c). Of 14 segments (32%) with improved kinesis during LDDE, 7 (50%) improved after surgery (true positive), whereas 24 of 40 segments (60%) with no improvement during LDDE also remained unchanged postoperatively (true negative) (Figure 2). Sensitivity, specificity, and diagnostic accuracy were therefore 30%, 77%, and 57%, respectively. Angiographic results: LV angiography in basal conditions disclosed 205 dysfunctional subsegments (64%) (defined as segments with an ejection fraction ⬍50%) of 320 segments available for analysis. During dobutamine infusion, none of these segments manifested further deterioration of function, whereas 96 (47%) showed a functional improvement. The remaining 109 dysfunctional segments (53%) did not show functional changes during dobutamine (Figure 3a). LV ejection fraction increased from 35 ⫾ 4% at baseline to 44 ⫾ 4% at peak infusion (p ⬍0.01). The postoperative angiographic studies demonstrated regional and global improvement in LV function; kinesis improved in 101 subsegments (49%), and LV ejection fraction increased from the preoperative value of 35 ⫾ 4% to 45 ⫾ 3% (p ⬍0.01). Of 96 segments with improved kinesis during LDDV, 56 (58%) were found improved at postoperative ventricular angiography (true positive) (Figure 3b); 90 of 109 segments (83%) with unchanged kine-
CORONARY ARTERY DISEASE/DOBUTAMINE VENTRICULOGRAPHY DETECTS MYOCARDIAL VIABILITY
373
an underestimation of segmental hypokinesia in basal condition, reducing LDDE sensitivity. In an attempt to overcome this fairly frequent clinical obstacle, we tested the application of dobutamine infusion during routine LV angiography. Considering the total group of patients, we demonstrated that LDDV is as sensitive, specific, and accurate as LDDE. In addition, LDDV is not influenced by thoracic features of the patients. 1. Gould KL. Myocardial viability: what does it
mean and how to measure? Circulation 1991;83: 333–335. 2. Sanchis J, Bodi V, Insa L, Go´mez-Aldaravi R, Berenguer A, Lo´pez-Lereu MP, Chorro FJ, Lo´pezFIGURE 3. Pie charts showing the effects of low-dose dobutamine infusion and of coroMerino V. Low-dose dobutamine testing using nary revascularization on regional systolic function assessed by left ventriculography. contrast left ventriculography in the same session as coronary angiography predicts the improvement of left ventricular function after coronary angioplasty in postinfarction patients. Am J Cardiol 1999;83:15–20. sis during LDDV also remained unchanged after sur- 3. Schiller NB, Shaha PM, Crawford M, De Maria A, Devereaux R, Feigenbaum H, Gutgesell H, Reichek N, Sahn D, Schnittger I, Silverman NH, Taijik AJ. gery (true negative) (Figure 3c). Recommendations for quantification of the left ventricle by two-dimensional The sensitivity and specificity of LDDV to identify echocardiography. J Am Soc Echocardiogr 1989;2:358 –367. dysfunctional segments capable of functional recovery 4. Bozzi G, Verna E, Skinner JM, Dwyer ML, Castelfranco M. Quantitative regional contraction analysis of cineventriculography: reporting, filling and rewere therefore 66% and 75%, respectively. Diagnostic trieval function using a personal computer. Cathet Cardiovasc Diagn 1989;2: accuracy for predicting functional improvement of 358 –367. 5. Cigarroa CG, de Filippi CR, Brickner ME, Alvarez LG, Wait MA, Grayburn dysfunctional segments after revascularization was PA. Dobutamine stress echocardiography identifies hibernating myocardium and 71%. Such values did not differ for subgroups of predicts recovery of left ventricular function after coronary revascularization. Circulation 1993;88:430 – 436. patients. 6. Perrone-Filardi P, Pace L, Prastaro M, Piscione F, Betocchi S, Squame F, Vezzuto P, Soricelli A, Indolfi C, Salvatore M, Chiariello M. Dobutamine echocardiography predicts improvement of hypoperfused dysfunctional myocardium after revascularization in patients with coronary artery disease. Circulation 1995;91:2556 –2565. 7. Arnese M, Cornel JH, Salustri A, Maat APWM, Elhendy A, Reijs AEM, Ten To our knowledge this is the first report that dem- Cate FJ, Keane D, Balk AHMM, Roelandt JRTC, Fioretti PM. Prediction of improvement of regional left ventricular function after surgical revascularization. onstrates that LDDV is able to identify hypoperfused A comparison of low-dose dobutamine echocardiography with 201Tl single emisand dysfunctional myocardium capable of recovering sion computed tomography. Circulation 1995;91:2748 –2752. 8. Afridi I, Grayburn PA, Panza JA, Oh JK, Zoghbi WA, Marwick TH. Myofunction after surgical revascularization. In recent cardial viability during dobutamine echocardiography predicts survival in payears, numbers of diagnostic techniques have been tients with coronary artery disease and severe ventricular systolic dysfunction. Coll Cardiol 1998;32:921–926. proposed to determine the presence and extent of J9.Am Kauffman GJ, Boyne TS, Denny DW, Smith WH, Beller GA. Comparison of 5–12 myocardial viability in ischemic cardiomyopathy rest thallium-201 imaging and rest technetium-99m sestamibi imaging for assessto identify patients who might benefit from coronary ment of myocardial viability in patients with coronary artery disease and severe left ventricular dysfunction. J Am Coll Cardiol 1996;27:1592–1597. revascularization as an alternative to medical therapy 10. Auerbach MA, Schoder H, Hoh C, Gambhir SS, Yaghoubi S, Sayre JW, 1,13,14 LDDE has been ex- Silverman D, Phelps ME, Schelbert HR, Czernin J. 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DISCUSSION
374 THE AMERICAN JOURNAL OF CARDIOLOGY姞
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