The evolution of stress echocardiography

History of the evolution of echocardiography

Echocardiography provides information regarding cardiac morphology, function and hemodynamics non-invasively. It is the most frequently performed cardiovascular examination after electrocardiography and chest X-ray. In less than half a century, this technique has evolved to a mainstay of cardiovascular medicine. The historical evolution of echocardiography is succinctly described including that of M-mode, two-dimensional, Doppler, stress, transesophageal, intraoperative, contrast, digital, three-dimensional and intracardiac echocardiography.

False-positive exercise echocardiograms: impact of sex and blood pressure response

BACKGROUND

Factors related to false-positive results of exercise echocardiography (ExE) to diagnose coronary disease have not been extensively studied. In addition, previous studies were performed before routine use of digital and tissue harmonic imaging. We evaluated the clinical and echocardiographic predictors of false-positive results during ExE.

METHODS

Four hundred sixty-four patients who had both coronary angiography and ExE were enrolled retrospectively. Significant coronary disease was defined by stenoses > or =50% lumen diameter.

RESULTS

Fifty-eight (13%) had false-positive results. Thirty-one (53%) of these patients were women, which was significantly higher than the percentage of women (25%) in the true-positive group (P <.001). Average peak systolic blood pressure (BP) in the false-positive group was significantly higher than in the true-positive group. Test specificity was decreased at higher levels of BP without change of sensitivity. Men demonstrated a decrease in specificity at peak systolic BP > or =200 mm Hg, whereas women showed a sharp decrease in specificity at BP > or =180 mm Hg. Wall motion score index (WMSI) after peak exercise and the proportion of high- and intermediate-risk patients according to Duke score were significantly lower in the false-positive than in the true-positive group.

CONCLUSIONS

The factors predictive of false-positive results during ExE to diagnose coronary disease were female sex, higher BP at peak exercise, lower risk by Duke score and lower number of abnormal segments and wall motion score index after peak exercise. Women appear to be susceptible to wall motion abnormalities caused by elevated exercise BP. These variables should be considered in the interpretation of ExE.

Simultaneous analysis of wall motion and coronary flow reserve of the left anterior descending coronary artery by transthoracic doppler echocardiography during dipyridamole stress echocardiography

BACKGROUND

Coronary flow reserve (CFR) can be measured in the left anterior descending artery (LAD) by dipyridamole transthoracic Doppler echocardiography (DTTDE). This information may critically improve the diagnostic accuracy of dipyridamole stress echocardiography, which is limited by moderate sensitivity.

OBJECTIVE

We sought to assess the feasibility and accuracy of value of DTTDE.

METHODS

We evaluated 752 consecutive patients (478 men; mean age, 64.7 years) referred for dipyridamole stress echocardiography. The diastolic velocity in the LAD was continuously monitored with pulsed Doppler at baseline and during hyperemia induced by the infusion of 0.84 mg/kg of dipyridamole. CFR was calculated as the ratio of maximal and basal diastolic velocity; a value < 2 was considered to indicate decreased CFR. Wall motion was assessed semiquantitatively. Coronary angiography was performed in 132 patients the week after DTTDE.

RESULTS

Adequate tracings were obtained in 95% of patients studied (715 of 752). In the subset of 132 patients undergoing coronary angiography, 71 patients (group A) showed a nonsignificant (<70%) and 61 patients (group B) a significant stenosis of the LAD. In group A, 65 had a normal wall-motion response (91.5% specificity) and 19 patients showed a decreased CFR (73.2% specificity; P =.1). In group B, new wall-motion abnormalities were seen in 42 patients (68.8% sensitivity), whereas CFR was decreased in 52 patients (86.8% sensitivity; P <.02).

CONCLUSION

Simultaneous assessment of wall motion and CFR of the LAD with DTTDE was highly feasible and safe. The information about CFR had a significantly higher sensitivity than the analysis of wall motion during dipyridamole stress echocardiography.

Segmental wall motion abnormalities during telerobotic totally endoscopic coronary artery bypass grafting

In addition to single-lung ventilation (SLV), intrathoracic CO2 insufflation is mandatory for adequate exposure during totally endoscopic coronary artery bypass grafting. With transesophageal echocardiography, we investigated biventricular myocardial wall motion in 25 patients with isolated disease of the left anterior descending coronary artery who underwent totally endoscopic coronary artery bypass grafting with the "Da Vinci" robotic surgical system. At distinct time points during the operation, a cine loop of both ventricles was registered from a transgastric mid-short-axis view. Myocardial wall motion analysis was performed according to an established segmentation model of the left ventricle and to an established five-point scale for wall motion (1, normal; 5, dyskinesia). Significant alterations from preoperative baseline wall motion were visible in the septal, inferior, and anterior segments of the left ventricle at some time during the prebypass period, combined with a markedly decreased PaO2 under SLV and increased intrathoracic pressure. The same findings applied to the right ventricle; however, wall motion abnormalities were more pronounced here. After myocardial revascularization, weaning from cardiopulmonary bypass, CO2 deflation, and return to double-lung ventilation, myocardial wall motion recovered to baseline values. Clinically significant hemodynamic instability did not occur. The data suggest that robot-assisted coronary artery bypass grafting leads to significant prebypass alterations of biventricular segmental wall motion. On the basis of our data, it cannot be definitively stated whether the observed results were due to reduced oxygenation during SLV and thus "real" myocardial ischemia, intrathoracic CO2 insufflation with positive pressure leading to mechanical compromise of the heart, absolute or relative hypovolemia, or a combination of these factors. However, in this cohort, which consisted of patients with single-vessel disease and good ventricular function, these changes were of limited clinical relevance.

IMPLICATIONS

Segmental myocardial wall motion was evaluated with transesophageal echocardiography during robot-assisted totally endoscopic coronary artery bypass grafting. Significant biventricular segmental wall motion abnormalities occurred before cardiopulmonary bypass under single-lung ventilation and carbon dioxide insufflation. The changes in myocardial wall motion were of limited clinical relevance.