Regional Wall Motion Score Research Articles

Beneficial Effect of Coronary Artery Bypass Grafting as Assessed by Quantitative Gated Single-Photon Emission Computed Tomography

The development of quantitative gated single-photon emission computed tomography (SPECT) has enabled the assessment of left ventricular perfusion, function and wall thickness in a single examination. Accordingly, the present study used gated SPECT to assess the benefit of coronary artery bypass grafting (CABG) in patients with coronary artery disease; 47 of those patients were evaluated before and 5 months after CABG. As a result of coronary revascularization, a significant improvement was observed in global ejection fraction (50+/-12 --> 53+/-11%; p<0.05). In 107 revascularized territories, the average regional reversible defect score (0.8+/-0.5 --> 0.2 +/-0.3; p<0.0001), average regional perfusion score at rest (0.6+/-0.6 --> 0.3+/-0.4; p<0.0001), average regional wall motion score (0.9+/-0.7 --> 0.7+/-0.5; p<0.05), and end-diastolic wall thickness (8.1+/-1.3 --> 8.6+/-1.5 mm; p<0.0005) all improved significantly. Even in 34 non-revascularized territories, the average regional reversible defect score (0.5+/-0.7 --> 0.2+/-0.5; p<0.03), average regional wall motion score (0.8+/-1.1 --> 0.5 +/-1.0; p<0.03) and end-diastolic wall thickness (8.0+/-1.4 --> 9.1+/-2.0 mm; p<0.03) all improved significantly. These results indicate that improvement in myocardial ischemia, hibernation and left ventricular function with CABG can be assessed in detail with gated SPECT.

Intraoperative TEE Using Tissue Doppler Modalities vs Regional Wall Motion Scoring in the Short Axis View

Intraoperative TEE Using Tissue Doppler Modalities vs Regional Wall Motion Scoring in the Short Axis View

Intraoperative Tissue Doppler Echocardiography. Longitudinal Tissue Velocity and Strain Analysis Is Superior to Regional Wall Motion Scoring

Intraoperative Tissue Doppler Echocardiography. Longitudinal Tissue Velocity and Strain Analysis Is Superior to Regional Wall Motion Scoring

Immunocytochemical evidence for inducible nitric oxide synthase and cyclooxygenase-2 expression with nitrotyrosine formation in human hibernating myocardium.

Myocardial hibernation may result from repetitive episodes of transient ischaemia leading to prolonged dysfunction. Inducible nitric oxide synthase (iNOS) expression has been demonstrated in animals following brief, non-lethal ischaemia-reperfusion injury. We therefore, hypothesised that in human hibernating myocardium: 1). iNOS would be present; 2). the reaction of nitric oxide and superoxide would form the strong oxidant peroxynitrite; 3) that this process would be accompanied by the expression of cyclooxygenase-2 (Cox-2) which interacts with NOS and whose products could further affect myocardial function. In sixteen patients with coronary artery disease (CAD), left ventricular biopsies were obtained from chronically dysfunctional segments subtended by a stenotic artery (> 75 %) and shown to be viable by (18)F-fluorodeoxyglucose positron emission tomography. Comparison was made with myocardial biopsies (n = 8) from normally contracting myocardium in patients undergoing coronary surgery, from unused transplant donors and at post-mortem. Regional wall motion score improved in all patients 6 months post-revascularisation (from 2.7 +/- 0.7 to 1.5 +/- 0.5; p < 0.001), confirming hibernation. Immunocytochemistry localized reactivity to iNOS, Cox-2 and nitrotyrosine (a marker of peroxynitrite formation) to cardiomyocytes from hibernating segments. No difference in reactivity to endothelial NOS was seen between hibernating and control cardiomyocytes. Cox-2 and iNOS are co-expressed in hibernating myocardium with nitrotyrosine suggesting nitric oxide production and peroxynitrite formation. We propose that this is secondary to ischaemia-reperfusion and that the products of these enzymes may have consequences for myocardial contractile function and survival.

Is There a Long-Term Predictive Value of Intraoperative Low-Dose Dobutamine Echocardiography in Patients Who Have Coronary Artery Bypass Graft Surgery with Cardiopulmonary Bypass?

In patients with coronary artery disease, chronic regional left ventricular systolic dysfunction at rest may be caused by hibernating or by infarcted myocardium. Intraoperative low-dose dobutamine (LDD) echocardiography reliably predicts the immediate recovery of regional myocardial function after coronary artery bypass graft (CABG) surgery. We sought to determine whether intraoperative LDD echocardiography would also predict recovery of regional function after 1 yr. Twenty-five patients with coronary artery disease who underwent CABG surgery with intraoperative LDD echocardiography were evaluated 1 yr later with a follow-up transthoracic echocardiogram. The covariates of left ventricular ejection fraction, old myocardial infarction, and diabetes mellitus were considered in an analysis of regional wall motion (RWM). A 16-segment model and a 1–5-point scoring system were used to evaluate 350 myocardial segments. Multiple logistic regression analysis was performed to determine whether response to intraoperative LDD echocardiography (5 μg · kg−1 · min−1) predicted changes in regional function at 1 yr. A segment was defined as stunned if the RWM score obtained during LDD infusion deteriorated after cardiopulmonary bypass but recovered in the 1-yr follow-up echocardiogram. A response to intraoperative LDD predicted changes in regional function at 1 yr. The overall odds of improvement in regional function were 2.22 times greater (95% confidence interval = 1.29, 3.82;P = 0.0039) with a positive response to intraoperative LDD. The positive predictive value of intraoperative LDD echocardiography for improvement in myocardial function was 0.81 and the negative predictive value was 0.34. The predictive values did not vary with the examined covariates. Of segments with unexpected deterioration of RWM immediately after cardiopulmonary bypass, 87% recovered at the time of the 1-yr follow-up echocardiogram. Contractile reserve demonstrated by intraoperative LDD echocardiography predicts regional function at 1 yr; however, the test cannot predict which segment will not recover. Most of unexpected regional ventricular systolic dysfunction immediately after CABG surgery can be attributed to myocardial stunning.

Comparison between Echocardiography and Gated SPECT in the Assessment of Left Ventricular Wall Motion in Patients with Acute Myocardial Infarction

Background and Objectives：Assessment of the regional left ventricular function provides valuable diagnostic and prognostic information of patients with coronary artery disease. The aim of the study was to analyze the agreement between wall motion scores, derived by gated single photon emission computed tomo-graphy (SPECT and echocardiography (Echo in myocardial infarction patients with a perfusion defect. Subjects and Methods：We studied the regional wall motion in 81 patients with an acute myocardial infar-ction, who underwent adenosine stress gated SPECT and Echo. Echo was performed in all the patients immediately prior to, or following, gated SPECT. The regional wall motion was evaluated by both modalities, and scored using a 16-segment model with a 4-point scoring system：1＝normal, 2＝mild and moderate hypokinesia, 3＝severe hypokinesia, 4＝akinesia or dyskinesia. Results：There was a high agreement in the left ventricular regional wall motion scores between the gated SPECT and the Echo of 84.2% of segments (1091/1296 segments, k＝ 0.76, p<0.0001. The agreement in the regional wall motion scores between the two modalities decreased significantly along the longitudinal axis of the left ventricle from 92.9% (301/324, k＝0.89, p<0.0001 at the apex, 84.6% (411/486, k＝0.77, p<0.0001 at the mid point, to 77.9% (379/486, k＝0.65, p<0.0001 at the basal segments (p<0.0001. Also, the agreement based on the degree of myocardial perfusion was 86.6% for segments with normal, or mild hypoperfusion, and 82.6% with moderate to severe hypoperfusion (p＝0.072. Conclusion：The gated SPECT had a good agreement with the Echo for the assessment of the left ventricular regional wall motion in patients with an acute myocardial infarction. These results support the clinical use of gated SPECT. (Korean Circulation J 2002;32 (9 :781-790

Prognostic implications of evaluation of contractile reserve in akinetic and hypokinetic segments during low dose dobutamine echocardiography in patients with acute myocardial infarction

Background: Previous studies have reported the prognostic value of myocardial viability (MV) detected using low-dose dobutamine echocardiography (DbE). However, viability was frequently evaluated as improvement in regional wall motion score index, which includes increased function in hypokinetic segments, in which viable myocardium is necessarily present. It is not known whether an evaluation focusing on akinetic segments, in which the possible presence of viable myocardium is unknown, might have more prognostic value. The aim of this study was to compare the prognostic value of the improvement of myocardial function during dobutamine infusion in akinetic and hypokinetic regions in patients with acute myocardial infarction (AMI). Methods: 191 patients with uncomplicated AMI and at least one akinetic segment were retrospectively selected from those consecutively examined at our echo-laboratory to evaluate MV using DbE. Myocardial viability was evaluated both as an increment in RWMSI (ΔRWMSI), which takes into consideration improvement in both akinetic and hypokinetic regions, and as an improvement of function in akinetic (Δ akinetic) and hypokinetic (Δ hypokinetic), segments considered separately. Follow-up evaluation was performed at 30±13 months. Results: On the basis of the ΔRWMSI, 94/191 patients were judged to have myocardial viability, whereas considering myocardial viability in akinetic segments only, 72/191 patients showed viability. At follow-up 18 patients had died (six viable considering ΔRWMSI; three viable considering Δ akinetic). The presence of a previous AMI, the site of AMI, RWMSI and the number of akinetic segments, and ΔRWMSI and Δ akinetic were related to mortality at univariate Cox analysis. At multivariate stepwise Cox regression analysis Δ akinetic, but not Δ hypokinetic proved to be significantly related to mortality. The Kaplan–Meier survival curves were no different in patients with or without viable myocardium evaluated as ΔRWMSI, while they were significantly different considering patients with or without viability in akinetic segments ( P=0.04). Conclusion: In conclusion our study confirms the prognostic importance of the evaluation of myocardial viability in infarcted patients. However, it points out that it is the presence of viability in akinetic segments that affects long-term survival in these patients. This supports the hypothesis that other mechanisms, above and beyond the effect on regional wall motion, are involved in the beneficial effects of myocardial viability.

Assessment of coronary flow velocity with transthoracic Doppler echocardiography during dobutamine stress echocardiography

OBJECTIVESThe purpose of this study was to evaluate the feasibility of measuring coronary flow velocity (CFV) by transthoracic Doppler echocardiography (TTDE) in the left anterior descending coronary artery (LAD) during contrast-enhanced dobutamine stress echocardiography (DSE). We also assessed the value of TTDE for detecting stress-induced myocardial ischemia in the LAD territory.BACKGROUNDNoninvasive assessment of both CFV and wall motion during DSE would enhance the diagnostic accuracy of DSE.METHODSOne hundred forty-four consecutive patients underwent CFV recording in the distal LAD by TTDE during contrast-enhanced DSE. Regional wall motion score index (WMSI) in the LAD territory and CFV ratio at peak stress (CFV ratio peak), defined as a ratio of CFV at peak stress to basal CFV, were obtained.RESULTSCoronary flow velocity was successfully recorded in 129 patients (90%) at baseline and during dobutamine infusion. Mean value of CFV ratio peak was 2.39 ± 0.83 (range: 0.84 to 4.40). There was good correlation between WMSI at peak stress and CFV ratio peak (r = 0.62, p < 0.001). Coronary flow velocity ratio peak was significantly lower in patients who developed stress-induced wall motion abnormality (WMA) in the LAD territory than it was in those patients without WMA (1.51 ± 0.51 vs. 2.76 ± 0.65, p < 0.001). A CFV ratio peak <2.1 had a sensitivity of 92% and a specificity of 86% for detecting the presence of stress-induced WMA.CONCLUSIONSAssessment of CFV in the distal LAD during DSE is feasible in the majority of cases and provides a CFV ratio for detecting stress-induced myocardial ischemia in the LAD territory.

Diastolic Dysfunction is Predictive of Difficult Weaning from Cardiopulmonary Bypass

Diastolic function is receiving more attention since echocardiographic measurements were developed and have become widely available. The importance and significance of diastolic dysfunction (DD) observed before cardiac surgery and its relationship with adverse outcomes, such as difficult separation from cardiopulmonary bypass (CPB), have not been fully explored. In this study, we hypothesize that DD can be a predictor for the need of inotropic support to successfully separate from CPB. Ninety-two consecutive patients underwent surgery during the study period. Twenty-six patients were excluded. From the remaining 66 patients, 52 had coronary artery bypass grafting alone and 14 combined procedures, valvular surgery, and reoperations (redo). Systolic and diastolic function was evaluated by two experts blinded as to the clinical data except for the age. The evaluation of diastolic function was done according to published guidelines. The demographic, echocardiographic, and hemodynamic variables were entered in a logistic regression analysis to determine which variables were independent predictors of difficult separation from CPB and the need for postoperative vasoactive support. DD was present in 20 patients (30%). Patients with DD had lower weight (P = 0.046), less frequent coronary artery bypass grafting alone (P = 0.0004), more myocardial infarction before surgery (P = 0.02), higher regional wall motion score index (P = 0.0002), and larger left ventricle (P = 0.03). Total CPB time (P = 0.004) and ischemic time (P = 0.007) were longer in the DD group. Patients with DD required more frequent inotropic support at the end of surgery (P = 0.006) and up to 12 h after surgery (P = 0.003). Multivariate logistic regression identified female sex, DD, and total CPB time as predictive of difficult weaning and inotropic requirements up to 12 h after surgery. Implications Abnormal diastolic filling patterns are frequently observed during cardiac surgery. The data support routine evaluation of diastolic function during echocardiographic cardiac assessment of patients undergoing cardiac surgery.

Diastolic dysfunction is predictive of difficult weaning from cardiopulmonary bypass.

Diastolic function is receiving more attention since echocardiographic measurements were developed and have become widely available. The importance and significance of diastolic dysfunction (DD) observed before cardiac surgery and its relationship with adverse outcomes, such as difficult separation from cardiopulmonary bypass (CPB), have not been fully explored. In this study, we hypothesize that DD can be a predictor for the need of inotropic support to successfully separate from CPB. Ninety-two consecutive patients underwent surgery during the study period. Twenty-six patients were excluded. From the remaining 66 patients, 52 had coronary artery bypass grafting alone and 14 combined procedures, valvular surgery, and reoperations (redo). Systolic and diastolic function was evaluated by two experts blinded as to the clinical data except for the age. The evaluation of diastolic function was done according to published guidelines. The demographic, echocardiographic, and hemodynamic variables were entered in a logistic regression analysis to determine which variables were independent predictors of difficult separation from CPB and the need for postoperative vasoactive support. DD was present in 20 patients (30%). Patients with DD had lower weight (P = 0.046), less frequent coronary artery bypass grafting alone (P = 0.0004), more myocardial infarction before surgery (P = 0.02), higher regional wall motion score index (P = 0.0002), and larger left ventricle (P = 0.03). Total CPB time (P = 0.004) and ischemic time (P = 0.007) were longer in the DD group. Patients with DD required more frequent inotropic support at the end of surgery (P = 0.006) and up to 12 h after surgery (P = 0.003). Multivariate logistic regression identified female sex, DD, and total CPB time as predictive of difficult weaning and inotropic requirements up to 12 h after surgery.

Field-by-field evaluation of intraoperative transoesophageal echocardiography interpretative skills

A quality assurance system is essential for the credibility and structured growth of anaesthesiology-based transoesophageal echocardiography (TEE) programmes. We have developed software (Q/A Kappa), involving a 400-line source code, capable of directly reporting kappa correlation coefficient values, using external reviewer interpretations as the `gold standard', and thereby allowing systematic assessment of the validity of intraoperative echocardiographic interpretation. This paper presents assessment of the validity of 240 intraoperative anaesthesiologists' echocardiographic interpretations, and, in addition, the results of field testing of this prototypical software. Data, derived from consecutive cardiac surgery patients, consisted of standardized two-dimensional transoesophageal echocardiographic, colour flow and Doppler imaging sequences. Intraoperative and off-line `gold standard' TEE interpretations were compared for 19 fields or variables using the Q/A Kappa program. The kappa correlation coefficients were highly variable and dependent on the examination field, ranging from 0.08 for apical regional wall motion scores to 1.00 for tricuspid regurgitation grade, left atrial measurement, aortic valve anatomy and left ventricular long axis and short axis global function. The correlation coefficients were also operator dependent. These data (480 interpretations) were also manually integrated into the equation required for calculation of values of the variable kappa correlation coefficient. The relationship between Q/A Kappa-derived values and manually calculated values was highly significant (p < 0.001; r = 1.0). The implications and possible explanations of the results for particular examination fields are discussed. This study also demonstrates successful seamless functioning of this software program from data entry, segmentation into tables and valid statistical analysis. These findings suggest that it is practical to provide sophisticated continuous quality improvement TEE data on a routine basis.

The Role of Echocardiography for Evaluation of the Acute Chest Pain Patients with Nonspecific ECG Findings

Objective：To evaluate diagnostic role of echocardiography in the patients of acute chest pain with nonspecific ECG findings we have performed prospective study. Subject and Method：79 out of 101 consecutive patients presenting to the emergency room with symtoms suggestive of acute coronary syndrome (ACS without diagnostic ECG change were studied. Presence and score of regional wall motion abnormality (RWMA were assessed according to the American Society of Echocardiography guideline (16 segment model by two-dimensional echocardiography within 4 hours after arrival. The diagnosis of acute myocardial infarction (AMI was confirmed by serial myocardial enzyme assay retrospectively. Results：Of the 28 patients with RWMA, 13 (46% had non-Q AMI, 8 (28% had unstable angina, 3 (11% had posterior AMI. Of the 51 patients with normal wall motion, 10 had gastroesophageal disease, 9 had variant angina, 3 had psychologic disease, 1 had aortic dissection and 1 had hypertrophic cardiomyopathy. Thus, Presence of RWMA by echocardiography had a sensitivity of 49% and a specificity of 88% for diagnosis of ACS. In 21 ACS patients with RWMA, regional wall motion score was significantly higher in AMI than in unstable angina (3.1±1.8 vs 1.0±2.2, p<0.05. As for the significant coronary artery stenosis, there was a higher incidence of multivessel disease in the patients with RWMA (64%. Conclusion：RWMA by two-dimensional echocardiography in the emergency room is not a sensitive but a specific technique to diagnose ACS patient with nonspecific ECG change, especially in posterior AMI and non-Q AMI.

Prediction of Functional Recovery After Revascularization in Coronary Artery Disease Using 18F-FDG and 123I-BMIPP SPECT

Clinical studies comparing fatty acid and glucose metabolism in relation to functional recovery of ischemic myocardium after coronary revascularization are scarce. This study evaluated the recovery of regional and global left ventricular function after coronary revascularization in relation to uptake patterns of beta-methyl-iodophenyl-pentadecanoic acid (BMIPP) and fluorodeoxyglucose (FDG) in patients with ischemic myocardial dysfunction. Patients with ischemic regional wall motion abnormality underwent baseline viability imaging with (18)F-FDG, (123)I-BMIPP, and (99m)Tc- methoxyisobutylisonitrile, and the regions with evidence for maintained tissue viability were revascularized. Mismatch of uptake score between two different single-photon emission CT (SPECT) images in the same myocardial region was graded as low or high mismatch. Regional and global left ventricular functional changes after revascularization were analyzed in relation to mismatch severity and difference of total uptake score in each SPECT image pair. A total of 33 vessels in 30 patients related to the asynergic regions were revascularized, and a total of 100 myocardial segments perfused by the revascularized vessels were analyzed. Segments showing high metabolic mismatch (FDG/BMIPP) had lowest regional wall motion score at baseline, representing the most severely impaired ischemic myocardium, and had highest improvement in regional wall motion score after revascularization. Difference of total uptake score between FDG and BMIPP showed a significant positive correlation with difference of ejection fraction between pre- and postrevascularization (r = 0.774, p < 0.0001). Combined metabolic SPECT imaging with FDG and BMIPP has the potential to identify severely impaired ischemic myocardium leading to more efficient therapeutic management of patients with coronary artery disease.

Low dose dobutamine stress echocardiography predicts the improvement of left ventricular systolic function in dilated cardiomyopathy

OBJECTIVETo determine whether dobutamine stress echocardiography can predict the improvement of left ventricular systolic function in patients with dilated cardiomyopathy (DCM).METHODSMyocardial contractile reserve, as assessed by dobutamine stress echocardiography, was...

Assessment of Regional Wall Motion Abnormalities with Real-Time 3-Dimensional Echocardiography

Accurate characterization of regional wall motion abnormalities requires a thorough evaluation of the entire left ventricle (LV). Although 2-dimensional echocardiography is frequently used for this purpose, the inability of tomographic techniques to record the complete endocardial surface is a limitation. Three-dimensional echocardiography, with real-time volumetric imaging, has the potential to overcome this limitation by capturing the entire volume of the LV and displaying it in a cineloop mode. The purpose of this study was to assess the feasibility of using real-time 3-dimensional (RT3D) echocardiography to detect regional wall motion abnormalities in patients with abnormal LV function and to develop a scheme for the systematic evaluation of wall motion by using the 3-dimensional data set. Twenty-six patients with high-quality 2-dimensional echo images and at least 1 regional wall motion abnormality were examined with RT3D echocardiography. For 2-dimensional echocardiography, wall motion was analyzed with a 16-segment model and graded on a 4-point scale from normal (1) to dyskinetic (4), from which a wall motion score index was calculated. Individual segments were then grouped into regions (anterior, inferoposterior, lateral, and apical) and the number of regional wall motion abnormalities was determined. The RT3D echocardiogram was recorded as a volumetric, pyramid-shaped data set that contained the entire LV. Digital images, consisting of a single cardiac cycle cineloop, were analyzed off-line with a computerized display of the apical projection. Two intersecting orthogonal apical projections were simultaneously displayed in cineloop mode, each independently tilted to optimize orientation and endocardial definition. The 2 planes were then slowly rotated about the major axis to visualize the entire LV endocardium. Wall motion was then graded in 6 equally spaced views, separated by 30 degrees, yielding 36 segments per patient. A higher percentage of segments were visualized with 2-dimensional versus RT3D echocardiography (97% vs 83%, respectively, P < .001). With the use of the 2-dimensional echocardiographic results as the standard, RT3D echocardiography detected 55 (96%) of 57 regional wall motion abnormalities. Analysis of the RT3D echocardiograms resulted in 3 false-negative and 5 false-positive findings. The total number of regional wall motion abnormalities was correctly classified by RT3D echocardiography in 19 (73%) of 26 patients. RT3D echocardiography detected 11 of 13 anterior, 19 of 20 inferoposterior, 9 of 9 lateral, and 15 of 15 apical wall motion abnormalities. An excellent correlation was found between the 2 techniques for assessment of the regional wall motion score index ( r = 0.89, P < .001). This initial clinical study demonstrates the feasibility and potential advantages of RT3D echocardiography for the assessment of regional LV function. Compared with 2-dimensional echocardiography, this new method permits recording of the entire LV in a single beat, allowing the extent and location of the regional wall motion abnormalities to be determined. (J Am Soc Echocardiogr 1999;12:7-14.)

Echocardiographic Studies of Dobutamine-Induced ST-Segment Elevation Before and After Coronary Artery Bypass Grafting in Patients with Old Q-Wave Myocardial Infarction

There is a controversy regarding the functional significance of stress-induced ST-segment elevation (STE) in Q leads. However, the effect of revascularization on the induction of STE was not investigated. We studied 35 patients with old Q-wave myocardial infarction who underwent coronary artery bypass grafting (CABG) of the infarct-related artery with dobutamine (up to 40 μg/kg per minute) stress echocardiography before and 3 months after CABG. Ischemia was defined as new or worsened wall motion abnormalities. Functional recovery was defined as a reduction of regional wall motion score of 1 or more in 2 or more segments from the pre-CABG to post-CABG resting echocardiogram with the use of the 16-segment/5-grade score model. STE (≥0.1 mV J-point elevation lasting 80 ms in ≥2 Q leads) occurred in 20 (57%) patients. There was no significant difference between patients with and those without STE before CABG with regard to the prevalence of peri-infarction ischemia (85% vs 80%) or index of improvement of regional function after CABG (0.26 ± 0.26 vs 0.29 ± 0.33). STE was reinduced to the same level in 4 patients after CABG, whereas 16 patients showed absent reinduction (8 patients) or reduced level (8 patients) of STE. Functional changes associated with absent reinduction or less STE after CABG were absence of reinduction of regional ischemia in 13 patients, improvement of resting regional function in 5 patients, and resection of scarred segments in 4 patients. Among the 4 patients with persistent dobutamine-induced STE, 1 patient had persistent ischemia and 2 showed worsening of resting regional function. Although dobutamine-induced STE in patients with old Q-wave infarction referred for CABG cannot identify patients with a higher prevalence of ischemia, the lack of reinduction of this pattern after CABG correlates with absent reinduction of ischemia in most of patients. (J Am Soc Echocardiogr 1999;12:48-54.)

Relation of plasma lipoprotein(a) with myocardial viability and left ventricular performance in survivors of myocardial infarction.

Previous studies have reported that high serum lipoprotein(a) levels may be responsible for total occlusion of the infarct-related artery via inhibition of intrinsic fibrinolysis during acute myocardial infarction. We evaluated whether this would result in a greater extent of myocardial necrosis and impaired left ventricular function in patients with high lipoprotein(a) levels. Sixty-eight patients with prior myocardial infarction, who were not receiving thrombolytic therapy underwent coronary angiography and stress-redistribution-reinjection Tl-201 scintigraphy. Antegrade TIMI flow in the infarct-related artery was lower (1.54 +/- 1.14 vs 2.15 +/- 1.05; p = 0.03) and the collateral index was higher (1.3 +/- 1.0 vs 0.8 +/- 0.9; p = 0.07) in patients with high lipoprotein(a) levels (> 30 mg/dl) compared to those with low lipoprotein(a) levels (< or = 30 mg/dl). Regional wall motion score index was lower (0.8 +/- 0.8 vs 1.4 +/- 0.5; p = 0.008) and global ejection fraction was higher (46 +/- 10% vs 40 +/- 11%; p = 0.03) in patients with low lipoprotein(a) levels. On SPECT images, the number of non-viable defects was higher in patients with high lipoprotein(a) levels (4.0 +/- 2.5 vs 1.9 +/- 1.3; p = 0.0002), whereas the number of viable defects was higher in those with low lipoprotein(a) levels (2.5 +/- 1.8 vs 1.5 +/- 1.3; p = 0.02). We conclude that high lipoprotein(a) levels may prolong the occlusion of infarct-related artery during acute myocardial infarction and lead to a greater extent of myocardial necrosis and impaired left ventricular function.

Coronary flow reserve may predict myocardial recovery after myocardial infarction in patients with TIMI grade 3 flow

Background The aim of the study was to determine whether the recovery of global and regional left ventricular function after successful percutaneous transluminal angioplasty (PTCA) could be predicted by measuring coronary flow reserve before performing the intervention.Methods and Results Thirty-two patients underwent PTCA 6.9 ± 3.4 days after a recent myocardial infarction. Coronary flow reserve was determined in the infarct-related artery before PTCA by using an intracoronary Doppler tipped wire. Global and regional wall motion were determined by 2-dimensional echocardiography before the Flowire study and again 7 weeks after the angioplasty. Whereas the global and regional wall motion score indices improved in 20 patients (recovery group), they deteriorated or did not change in 9 patients (nonrecovery group). Coronary flow reserve distal to the lesion in the infarct-related artery was significantly higher in the recovery group (1.43 ± 0.57 vs 0.98 ± 0.70, P =.0001). Coronary flow reserve distal to the lesion in the infarct-related artery was <1.1 in patients whose global or regional left ventricular function did not improve at follow-up, whereas flow reserve ranged between 1.1. and 1.8 while patients in whom left ventricular function improved.Conclusions These results suggest that the absence of inducible coronary flow reserve may predict failure of left ventricular systolic function to improve between the first and sixth week after infarction. Measurement of flow reserve with a Flowire at the time of diagnostic angiography after recent myocardial infarction may ultimately prove helpful in deciding whether to proceed with revascularization. (Am Heart J 1998;136:335-44.)

Pathophysiologic mechanisms underlying dobutamine- and exercise-induced wall motion abnormalities

Background Dobutamine and exercise echocardiography are accepted as tests of comparable efficacy for the diagnosis of coronary artery disease. Although dobutamine has been classified as “exercise simulating,” the mechanisms of ischemia with dobutamine and exercise have not been well studied. This study sought to compare the determinants of myocardial oxygen consumption. Methods and Results We studied 54 patients with coronary artery disease undergoing dobutamine and exercise stress. A subgroup of 13 patients with comparable degrees of wall motion abnormalities and ST-segment changes during both stresses were selected to compare the determinants of ischemia in comparable circumstances. Dobutamine was infused to a mean maximal dose of 32 ± 8 μg/kg/min, and exercise was stopped at an average of 135 ± 25 W. The mean regional wall motion score was not statistically different between the two protocols ( p = 0.27). At the onset of wall motion abnormalities and peak stress, the heart rate increased significantly less during dobutamine than during exercise (106 ± 23 vs 126 ± 19 beats/min, p < 0.001). The same was true of systolic blood pressure (155 ± 21 vs 205 ± 24 mm Hg, p < 0.001) and the rate-pressure product (16.5 ± 4.6 vs 25.9 ± 5, p < 0.001). Cardiac volumes were similar during both tests. Conclusions Ischemia occurs at a lower level of external cardiac work during dobutamine than during exercise stress. We suspect that additional mechanisms, such as the oxygen wasting effect of dobutamine, may be responsible for this observation. (Am Heart J 1998;136:63-70.)

Prospective, randomized trial comparing blood and oxygenated crystalloid cardioplegia in reoperative coronary artery bypass grafting

Objectives: Reoperative coronary artery bypass grafting presents unique challenges for myocardial preservation. The purpose of this study was to compare oxygenated blood cardioplegia with oxygenated crystalloid cardioplegia during reoperative coronary artery bypass grafting using transesophageal echocardiography to assess regional wall motion of the left ventricle before and after cardiopulmonary bypass. Methods: Sixty-one patients undergoing reoperative coronary artery bypass grafting were prospectively randomized to receive oxygenated blood cardioplegia or oxygenated crystalloid cardioplegia delivered with a combined antegrade-retrograde technique. Transgastric short axis views of the left ventricle were made with transesophageal echocardiography during the operation before cardiopulmonary bypass and immediately after cardiopulmonary bypass. Regional wall motion was graded by a blinded observer, and before cardiopulmonary bypass scores were compared with after cardiopulmonary bypass scores. Results: No significant differences were found in the change in regional wall motion score from before cardiopulmonary bypass to after cardiopulmonary bypass between the blood and crystalloid cardioplegia groups. Conclusions: This study found blood and crystalloid cardioplegia to be equally efficacious for myocardial preservation during reoperative coronary artery bypass grafting. (J Thorac Cardiovasc Surg 1998;115:1166-71)