Comparison of low-dose dobutamine ventriculography with low-dose dobutamine echocardiography for predicting regional improvement in left ventricular function after coronary artery bypass grafting

The demonstration of a contractile reserve during low-dose 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.     

Preoperative comparison of different noninvasive strategies for predicting improvement in left ventricular function after coronary artery bypass grafting

Thallium-201 (Tl-201) imaging and dobutamine stress echocardiography (DSE) are the most frequently used tests in the clinical setting for assessing viability. However, Tl-201 has a suboptimal specificity and DSE a suboptimal sensitivity to predict functional improvement after revascularization. F18-fluorodeoxyglucose (FDG) imaging is considered highly accurate, but availability is limited. Sequential imaging of Tl-201 and DSE may improve accuracy for assessing viability and may be comparable to FDG. Forty-seven patients with ischemic cardiomyopathy underwent Tl-201 single-photon emission computed tomography (SPECT) at rest (4-hour delayed imaging), DSE, and FDG SPECT before bypass surgery. Sensitivity, specificity, and accuracy of 2 sequential strategies were compared with those of FDG SPECT. Strategy 1 considered Tl-201 imaging as the first step, followed by DSE in patients with an intermediate likelihood of viability on Tl-201. Strategy 2 considered DSE as the first step, followed by Tl-201 imaging. Left ventricular ejection fraction was assessed before and 6 months after revascularization, and improvement of >/=5% was considered significant. Tl-201 had a high sensitivity (95%, p <0.05 vs DSE) with a low specificity (57%, p <0.05 vs DSE). DSE had a low sensitivity (63%, p <0.05 vs Tl-201) with a high specificity (89%, p <0.05 vs Tl-201). Both strategies 1 and 2 resulted in high sensitivities (89% and 89%, respectively) and high specificities (89% and 86%, respectively), compared with FDG SPECT (sensitivity 89%, specificity 86%). Sequential testing by Tl-201 SPECT and DSE has a comparable accuracy to FDG SPECT to predict improvement in left ventricular ejection fraction after revascularization. In centers without access to FDG, sequential imaging with Tl-201 and DSE offers an accurate alternative for assessing myocardial viability.     

Low-dose dobutamine radionuclide ventriculography for prediction of myocardial viability: quantitative analysis of regional left ventricular function

BACKGROUND: It is important to distinguish viable myocardium from necrotic tissue in order to decide upon therapy in patients with ischemic heart disease. HYPOTHESIS: We verified the hypothesis that quantitative analysis of regional left ventricular function using low-dose dobutamine radionuclide ventriculography (RNV) can sensitively predict myocardial viability and compared its usefulness with thallium-201 (201Tl) single-photon emission computed tomography (201Tl-SPECT). METHODS: Radionuclide ventriculography at rest and during low-dose dobutamine infusion (5 micrograms/kg/min), 201Tl-SPECT, and coronary angiography were performed in 51 subjects with severe ischemia-related stenosis of coronary arteries and 3 subjects without coronary artery disease. 201Tl uptake was assessed as normal (control), low perfusion (LP), or defect. We compared the response of regional function to dobutamine with the regional 201Tl uptake. The accuracy of both methods for identifying viable myocardium was investigated in 17 patients who underwent successful coronary revascularization, with a resulting improvement in wall motion. RESULTS: The increase in regional ejection fraction (delta r-EF) in response to dobutamine was significantly greater in the control (12 +/- 6%) and LP (16 +/- 11%) regions than in the defect (5 +/- 10%) regions. The increase in one-third regional ejection fraction (delta r-1/3EF) was also significantly higher in the control (14 +/- 7%) and LP (10 +/- 8%) regions than in the defect regions (5 +/- 6%). We defined myocardial viability as a delta r-EF > 5% or a delta r-1/3EF > 2%. The sensitivity and specificity of the delta r-EF for identification of myocardial viability were 91.4 and 55.5%, respectively. The sensitivity and specificity of the delta r-1/3EF were 91.4 and 66.6%, respectively; the corresponding values for 201Tl SPECT were 74.2 and 77.8%. CONCLUSION: Low-dose dobutamine RNV with quantitative analysis of regional left ventricular function was more sensitive for identification of viable myocardium than 201Tl-SPECT.     

冠状动脉旁路术与左心室功能关系研究

目的研究冠状动脉旁路术（CABG）术前与术后早期左室功能的变化,并找出其影响因素。方法 103例行CABG术患者,应用心脏彩色多普勒超声测定其术前及术后4～7 d左室射血分数（LVEF）、缩短分数（FS）及二尖瓣血流E峰与A峰的比值（E/A）。结果术后LVEF值、FS值较术前减低（P〈0.01）;术前LVEF值、术前FS值、左前降支狭窄程度、NYHA心功能分级是影响左室功能下降的主要因素。结论 CABG术后早期可出现左室收缩功能下降,为缺血再灌注后的心肌顿抑现象,应积极加以治疗。     

Relation between QRS changes and left ventricular function after coronary artery bypass grafting

Preoperative and serial postoperative electrocar-diograms (ECGs) were reviewed in 104 patients undergoing rest and exercise radionuclide angiocardiography before and 1 to 12 months after coronary artery bypass grafting (CABG). Five patient groups were defined by ECG findings before and after CABG: Group I—normal ECG before and no ECG change after CABG; Group II—prior myocardial infarction by ECG before but no QRS change after CABG; Group III—all patients with a minor QRS change (< 0.04-second Q wave, loss of R-wave amplitude) after CABG; Group IV—all patients with a major QRS change (≥ 0.04-second Q wave) after CABG; Group V—all patients without new Q waves or loss of R-wave amplitude but with a major QRS change (conduction disturbance) after CABG. Mean resting ejection fraction changed little after CABG in all groups, although the 0.03 increase in Group I was significant (p < 0.05). Group IV had the largest decrease in resting ejection fraction after CABG (0.04), but this was not statistically significant. Mean exercise ejection fraction increased significantly (p < 0.0001) in Groups I, II and III but not in Groups IV and V. QRS changes do not consistently reflect impairment of left ventricular (LV) function after CABG.     

Decreased right ventricular function after coronary artery bypass grafting

Decreased right ventricular function after coronary artery bypass grafting is a common and well-known (if not well-understood) phenomenon.We prospectively evaluated right ventricular function via echocardiographic tricuspid annular motion, tricuspid annular velocity, and right ventricular strain analysis before and after coronary artery bypass grafting. We also evaluated the effect of right coronary artery disease and revascularization on post-coronary artery bypass grafting, right ventricular function, and interventricular septal motion.We performed baseline echocardiography in 250 candidates for coronary artery bypass grafting, and we repeated echocardiography in 240 of those patients 1 year after coronary artery bypass grafting. We evaluated right ventricular function via tricuspid annular motion, tricuspid annular velocity, and right ventricular strain analysis, all measured at the right ventricular free wall.Right ventricular function as evaluated by tricuspid annular motion showed a significant reduction 1 year after coronary artery bypass grafting (21.7 vs 12.1 mm; P < 0.001) compared with preoperative measurements. Right ventricular tissue velocity (14.0 vs 7.0 cm/s; P < 0.001) and right ventricular strain (20.3% vs 11.6%; P < 0.001) were also significantly reduced after coronary artery bypass grafting. Interventricular septal motion was paradoxical in 97% of the patients 1 year after coronary bypass.Right ventricular function remained depressed for as long as 1 year after coronary artery bypass grafting. These findings were independent of the state of the right coronary artery and the graft. It is likely that the interventricular septum is recruited to maintain right ventricular stroke volume after coronary artery bypass grafting.     

Effect of coronary artery bypass grafting on left ventricular diastolic function

Because left ventricular (LV) diastolic function is abnormal in patients with coronary artery disease (CAD), pulsed Doppler echocardiography was used to evaluate LV filling before and after coronary artery bypass grafting (CABG). Filling was evaluated by Doppler in 2 studies: (1) in a group of 41 unpaired patients (11 with angiographically normal coronary arteries, 14 with CAD but without CABG and 16 at 1 week after CABG) and (2) in a group of 12 patients with CAD before and 1 week after CABG. Doppler sampling at the level of the mitral anulus was analyzed for the deceleration half-time and for the ratio of peak late (A) to peak early (E) filling velocity, measures reflecting early ventricular filling and the relative contribution of atrial contraction to ventricular filling. In the first study the deceleration half-time was significantly prolonged in both CAD and CABG groups. The late to early peak transmitral velocity ratio, however, was significantly prolonged only in the nonrevascularized CAD patients. In the second group of CAD patients studied before and 1 week after surgical revascularization, both the late to early peak transmitral velocity ratio and the deceleration half-time showed significant postoperative improvement. Thus, patients with CAD showed impairment in early LV filling and a compensatory increase in the proportion of filling with active atrial contraction. Successful CABG appears to result in normalization of early filling and decreased reliance on active atrial transport.     

Comparison of left ventricular diastolic function after on-pump versus off-pump coronary artery bypass grafting

We evaluated diastolic function in patients who underwent elective revascularization by standard on-pump coronary artery bypass graft (CABG) surgery versus off-pump CABG. Diastolic function improved in both groups, but indexes of early diastolic filling and myocardial relaxation improved more in patients who underwent on-pump than off-pump CABG.     

Usefulness of dobutamine Tc-99m sestamibi-gated single-photon emission computed tomography for prediction of left ventricular ejection fraction outcome after coronary revascularization for ischemic cardiomyopathy

Gated single-photon emission computed tomography (SPECT) imaging allows analysis of myocardial perfusion and assessment of baseline global and regional left ventricular (LV) function and their changes during low-dose dobutamine infusion. The study examined whether the changes in LV ejection fraction induced by dobutamine and evaluated using technetium-99m sestamibi- gated SPECT predict the evolution of ejection fraction after revascularization in patients with ischemic cardiomyopathy. Thirty-seven patients underwent resting and dobutamine nitrate-enhanced sestamibi-gated SPECT before revascularization and baseline-resting sestamibi gated SPECT after intervention to assess global functional changes. A postrevascularization improvement in ejection fraction > or =5 U was defined as significant. At follow-up, ejection fraction increased significantly in 19 patients. According to receiver-operating characteristic curve analysis, an increase in ejection fraction > or =5 U during dobutamine was the optimal cutoff value for predicting a significant postrevascularization improvement, with 79% sensitivity, 78% specificity, and 78% accuracy. A significant correlation was found between dobutamine and postrevascularization ejection fraction (r = 0.85; p <0.0001). The increase in ejection fraction during dobutamine is a good predictor of an improvement in ejection fraction after revascularization. This represents another important diagnostic contribution obtained using gated SPECT imaging for the assessment of myocardial viability in patients with ischemic cardiomyopathy.     

Usefulness of the ejection fraction response to dobutamine infusion in predicting functional recovery after coronary artery bypass grafting in patients with left ventricular dysfunction

Quantification of dysfunctional but viable myocardium has high prognostic value for improvement of left ventricular (LV) function after coronary artery bypass grafting (CABG). Dobutamine stress echocardiography (DSE) can assess viable myocardium by segmental wall motion changes during stress. However, analysis of wall motion is subjective with only moderate interinstitutional agreement (70%) and frequently overestimates functional improvement after CABG. In contrast, calculation of ejection fraction (EF) is less subjective and allows a more precise quantification of global contractile reserve. The aim of the study was to compare the prognostic value of EF response and segmental wall motion changes during DSE for the prediction of LV functional recovery after CABG. Forty patients underwent DSE before CABG. EF responses were assessed at rest, low-dose dobutamine, and at peak stress using the biplane disk method. Wall motion was scored using a 16-segment 5-point model. Resting radionuclide ventriculography (RNV-LVEF), performed before and 8 ± 2 months after CABG, was used as an independent reference. Five patients were excluded because of perioperative infarction or poor echo images. In 11 of 35 patients, RNV-LVEF recovered >5%. Improvement in EF during dobutamine infusion predicted RNV-LVEF recovery after CABG significantly better than segmental wall motion changes (72% vs 53%, p = 0.03). A biphasic EF response (i.e., improvement in ≥10% at low dose and subsequent worsening at peak stress) had the highest predictive value (80%) for late functional recovery. In conclusion, EF response to dobutamine infusion was superior to segmental wall motion changes in predicting RNV-LVEF recovery after CABG.     

非体外循环冠状动脉旁路移植术在左心室功能低下患者中的应用

目的:分析左心室功能低下(EF<40%)冠心病患者,接受非体外循环冠状动脉旁路移植手术(OPCAB)的疗效,改进左心室功能低下冠心病患者的治疗策略。方法:回顾性分析2006年以来我院手术组对37例左心室功能低下的冠心病患者,行OPCAB后手术前后疗效的对比。结果:2例患者死亡,1例死于术后肺部感染,1例死于术后低心排出量综合征(低心排),病死率5%。21例患者使用主动脉内球囊反搏器(IABP),其中7例在术前放置,14例在术中或术后放置。35例患者术后左心室射血分数(EF值)较术前有明显改善(P<0.05);左心室舒张末期内径、左心室收缩末径均较术前下降(P<0.05)。结论:对于左心室功能低下的冠心病患者,OPCAB是一种有效的治疗方法。及时使用主动脉球囊反搏,以及合理应用正性肌力药物对于降低患者病死率,减少患者住院时间具有重要意义。     

Utility of positron emission tomography in predicting improved left ventricular ejection fraction after coronary artery bypass grafting among patients with ischemic cardiomyopathy

The objective of this study was to determine whether preoperative estimates of regional myocardial uptake of (18)-F-fluorodeoxyglucose (FDG) could predict postoperative improvement in ejection fraction in patients undergoing coronary artery bypass grafting (CABG) for ischemic cardiomyopathy. 20 consecutive patients [left ventricular ejection fraction (LVEF) /=5% change noted in 7 patients (group 1) and <5% noted in 10 patients (group 2). No preoperative or perioperative clinical variable could predict those with improved ventricular function. The relative amount of FDG uptake in the anterior wall was higher in group 1 compared with group 2 (93 +/- 9 vs. 81 +/- 13%; p < 0.05) and correlated with the change in LVEF post-CABG (r = 0.50; p < 0.05). >88% of FDG uptake in the LAD region had a positive predictive accuracy of 67% and negative predictive accuracy of 88% for improved LVEF postbypass. Late follow-up estimates of LVEF (median of 10 months) showed that early changes in function were sustained. In summary, among patients with severe coronary artery disease and depressed LVEF, ventricular function may improve early postrevascularization. PET estimates of relative FDG uptake in the anterior wall help predict those individuals who are likely to have the greatest increment in LVEF.     

Off-pump coronary artery bypass grafting in left ventricular dysfunction

Between August 2004 and May 2006, 124 patients undergoing coronary artery bypass grafting with ejection fractions 相似文献   

实时三维超声心动图评价冠状动脉旁路移植术前后左心室功能

目的应用实时三维超声心动图定量评价冠状动脉旁路移植术前后左心室功能。方法选择行冠状动脉旁路移植术的冠心痛患者28例(冠心病组)和同期住院的其他疾病患者18例(对照组),应用实时三维超声心动图对2组左心室收缩末容积(LVESV)、左心室舒张末容积(LVEDV)、LVEF、左心室最大射血速率(LVPER)、左心室最大充盈速率(LVPFR)等参数进行比较。结果与对照组比较,冠心病组患者术前LVESV、LVEDV明显升高,LVEF、LVPER、LVPFR明显降低;与术前比较,冠心病组患者术后LVESV、LVEDV明显降低,LVEF、LVPER、LVPFR明显升高(P0.05)。结论实时三维超声心动图能较准确测量左心室容积、LVEF,并评价冠状动脉旁路移植术前后左心室功能。     

Evaluation of left ventricular early diastolic function after coronary artery bypass grafting relating to myocardial damage

This clinical study was undertaken to evaluate resting left ventricular early diastolic function relating to perioperative myocardial damage after coronary artery bypass graft (CABG) with radionuclide ventriculography. Forty-eight cases undergoing CABG were divided into two groups--Group I: not complicated with perioperative myocardial infarction (PMI), and Group II: complicated with PMI. In group I (42 cases), early diastolic parameters such as peak filling rate (1/3 PFR) and mean filling rate (1/3 FR(m)) during first third diastole were not impaired in the postoperative and follow up periods. In contrast, in Group II (6 cases), early diastolic parameters were significantly decreased to 157 +/- 74% EDV/sec of 1/3 PFR(pre op: 234 +/- 74, p less than 0.05) and 153 +/- 80% EVD/sec of 1/3 FR(m) (pre op: 231 +/- 86, p less than 0.05) in the postoperative period, and these parameters were still decreased in follow up period. The time to peak filling rate, normalized to diastolic time (TPFR/DT) of Group II cases, was severely prolonged in both periods. From these results, the complication of perioperative myocardial infarction was suggested by the decrease of early diastolic function and the prolongation of the time to peak filling rate. Early diastolic function was a more sensitive parameter than systolic function in the detection of impaired cardiac function in those cases with perioperative myocardial damage after CABG.     

Exercise radionuclide assessment of left ventricular function before and after coronary bypass surgery

The effects of elective saphenous vein coronary artery bypass surgery on left ventricular ejection fraction were assessed by using exercise first-pass radionuclide angiography in 66 consecutive patients. All patients with left main coronary artery or concomitant valvular disease were eliminated from the study. Before surgery, 7 patients had normal postexercise left ventricular function (Group 1), 33 had normal resting left ventricular function with an abnormal response to exercise (Group 2), and 26 had an abnormal resting left ventricular ejection fraction with an abnormal response to exercise (Group 3). Following surgery, patients in all three groups had no change in mean resting left ventricular ejection fraction; however, patients in Groups 2 and 3 had significant improvement in mean postexercise left ventricular ejection fraction (p less than 0.0001 and p less than 0.0054 respectively), whereas patients in Group 1 did not. Previous studies reported improvement in postexercise ejection fraction in patients with reduced resting left ventricular function and with an ischemic response to exercise (Group 3). But this is the first study to confirm improvement in postexercise function in patients with normal resting function and an ischemic response to exercise (Group 2).