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Regional Myocardial Performance Index for Diagnosis of Pulmonary Embolism in Patients With Echocardiographic Signs of Pulmonary Hypertension
744
The American Journal of Cardiology (www.AJConline.org)
1. Burstein JM, Gidrewicz D, Hutchison SJ, Holmes K, Jolly S, Cantor WJ. Impact of radial artery cannulation for coronary angiography and angioplasty on radial artery function. Am J Cardiol 2007;99:457– 459. 2. Agostoni P, Biondi-Zoccai GG, de Benedictis ML, Rigattieri S, Turri M, Anselmi M, Vassanelli C, Zardini P, Louvard Y, Hamon M. Radial versus femoral approach for percutaneous coronary diagnostic and interventional procedures; Systematic overview and metaanalysis of randomized trials. J Am Coll Cardiol 2004;44:349 –356. 3. Kamiya H, Ushijima T, Kanamori T, Ikeda C, Nakagaki C, Ueyama K, Watanabe G. Use of the radial artery graft after transradial catheterization: is it suitable as a bypass conduit? Ann Thorac Surg 2003;76:1505–1509. 4. Desai ND, Cohen EA, Naylor CD, Fremes SE. A randomized comparison of radial-artery and saphenous-vein coronary bypass grafts. N Engl J Med 2004;351:2302–2309. 5. Desai ND, Naylor CD, Kiss A, Cohen EA, Feder-Elituv R, Miwa S, Radhakrishnan S, Dubbin J, Schwartz L, Fremes SE. Impact of patient and target-vessel characteristics on arterial and venous bypass graft patency: insight from a randomized trial. Circulation 2007;115: 684 – 691. 6. Aptecar E, Pernes JM, Chabane-Chaouch M, Bussy N, Catarino G, Shahmir A, Bougrini K, Dupouy P. Transulnar versus transradial artery approach for coronary angioplasty: the PCVICUBA study. Catheter Cardiovasc Interv 2006;67:711–720. doi:10.1016/j.amjcard.2007.02.045
Regional Myocardial Performance Index for Diagnosis of Pulmonary Embolism in Patients With Echocardiographic Signs of Pulmonary Hypertension I read with great interest the report by Hsiao et al,1 which confirmed that the right ventricular (RV) myocardial performance index (MPI) was significantly higher in patients with pulmonary embolism (PE) than in others; that patients without PE had concordant changes in the RV and left ventricular (LV) MPIs; that in patients with acute PE, the RV MPI became higher but the LV MPI was relatively constant; that using the RV MPI divided by the LV MPI (the V index), PE could be distinguished in patients with echocardiographic signs of pulmonary hypertension (PH); and that by receiver-operating characteristic curve analysis, a V index ⬎1.2 identified PE with sensitivity of 82% and specificity of 83%, suggesting that the V index is a useful parameter to assess the possibility of PE in patients with echocardiographic signs of PH. The methods and interpretation of the results, however, raise several concerns.
Hsiao et al1 described in the abstract that 100 patients with echocardiographic signs of PH were enrolled in this study after informed consent was obtained and that PE was found in 50 patients by multidetector-row computed tomography of the chest. That is to say, 50 patients with PE (the PE group) all had echocardiographic signs of PH, defined by the investigators as (1) pulmonary arterial systolic pressure (PASP) ⬎40 mm Hg and (2) evidence of RV dilation or dysfunction. However, the average value of PASP in the PE group was 40 mm Hg in Table 1, were the PASP value of 50 patients all ⬎40 mm Hg which were not well described in the study by Hsiao et al1? If not, was there a contrary description or slip of the pen between the abstract and Table 1? A mechanism of ventricular interaction in PH can be described as follows2: (1) at rest, cardiac function is characterized by RV systolic overload due to PH and diastolic overload with tricuspid regurgitation, whereas the left ventricle has diastolic underloading and reduced compliance, LV systolic performance remains preserved; and (2) during exercise, RV systolic performance further worsens, with a reduction in stroke volume and the ejection fraction, and consequently LV stroke volume decreases because of underfilling, and heart rate becomes the mechanism by which cardiac output increases. It is likely that the extent of RV and LV dysfunction was well related to pulmonary arterial pressure. In Hsiao et al’s study,1 PASP in the PH group was significantly higher than that in the PE group, which could have caused the discordance of the changes in LV and RV dysfunction and further affected the sensitivity and specificity of the V index identifying PE. Therefore, the sensitivity and specificity of the V index in identifying PE with the same level of PASP in PH and PE needs to be studied further. In addition, in Hsiao et al’s study,1 the duration of PH in the PH and PE groups was not well described, which could have caused the discordance of the changes in LV and RV dysfunction and further affected the sensitivity and specificity of the V index in identifying PE. This issue requires further study. Ze-Zhou Song, MM Hangzhou, China 5 March 2007
1. Hsiao SH, Yang SH, Wang WC, Lee CY, Lin SK, Liu CP. usefulness of regional myocardial performance index to diagnose pulmonary embolism in patients with echocardiographic signs of pulmonary hypertension. Am J Cardiol 2006; 98:1652–1655. 2. Nootens M, Wolfkiel CJ, Chomka EV, Rich S. Understanding right and left ventricular systolic function and interactions at rest and with exercise in primary pulmonary hypertension. Am J Cardiol 1995;75:374 –377. doi:10.1016/j.amjcard.2007.03.012
A Novel Method of Two-Dimensional Echocardiographic Tracking I read with great interest the study by Ogawa et al,1 which confirmed that there was excellent agreement between the 2-dimensional tracking and manual methods for left ventricular (LV) wall thickness (r ⫽ 0.99) and percentage wall thickness (%WT) (r ⫽ 0.97); that the mean differences in LV wall thickness and %WT were 0.1 ⫾ 0.4 mm and 0 ⫾ 5.4%, respectively; and that average %WT was significantly decreased in regions of hypokinetic or akinetic wall motion compared with those of normal motion (18 ⫾ 4% and 4 ⫾ 4% vs 39 ⫾ 10%, p ⬍0.001), suggesting that this 2-dimensional tracking method can be used for the noninvasive, automated quantitation of LV wall motion in 2-dimensional echocardiography. The methods and interpretation of the results, however, raise several concerns. It is well known that segmental myocardial motion is complex, with 3 separate components: radial motion, longitudinal motion, and rotational motion. In addition, segmental myocardial motion could be affected by cardiac global motion and adjacent myocardial motion. In the study by Ogawa et al,1 however, segmental LV wall motion, including normokinetic, hypokinetic, akinetic, and dyskinetic, was evaluated by means of visual estimation by an experienced examiner without knowledge of the study patients. Therefore, the visual estimation of regional wall motion could be more subjective, less reproducible, and even more inaccurate, even though it was performed by an experienced examiner. It is well known that the accuracy of ultrasonic strain and strain rate measurements to evaluate segmental myocardial motion has been validated, and ranges of normal values have been recently established in healthy volun-
The American Journal of Cardiology (www.AJConline.org)
1. Burstein JM, Gidrewicz D, Hutchison SJ, Holmes K, Jolly S, Cantor WJ. Impact of radial artery cannulation for coronary angiography and angioplasty on radial artery function. Am J Cardiol 2007;99:457– 459. 2. Agostoni P, Biondi-Zoccai GG, de Benedictis ML, Rigattieri S, Turri M, Anselmi M, Vassanelli C, Zardini P, Louvard Y, Hamon M. Radial versus femoral approach for percutaneous coronary diagnostic and interventional procedures; Systematic overview and metaanalysis of randomized trials. J Am Coll Cardiol 2004;44:349 –356. 3. Kamiya H, Ushijima T, Kanamori T, Ikeda C, Nakagaki C, Ueyama K, Watanabe G. Use of the radial artery graft after transradial catheterization: is it suitable as a bypass conduit? Ann Thorac Surg 2003;76:1505–1509. 4. Desai ND, Cohen EA, Naylor CD, Fremes SE. A randomized comparison of radial-artery and saphenous-vein coronary bypass grafts. N Engl J Med 2004;351:2302–2309. 5. Desai ND, Naylor CD, Kiss A, Cohen EA, Feder-Elituv R, Miwa S, Radhakrishnan S, Dubbin J, Schwartz L, Fremes SE. Impact of patient and target-vessel characteristics on arterial and venous bypass graft patency: insight from a randomized trial. Circulation 2007;115: 684 – 691. 6. Aptecar E, Pernes JM, Chabane-Chaouch M, Bussy N, Catarino G, Shahmir A, Bougrini K, Dupouy P. Transulnar versus transradial artery approach for coronary angioplasty: the PCVICUBA study. Catheter Cardiovasc Interv 2006;67:711–720. doi:10.1016/j.amjcard.2007.02.045
Regional Myocardial Performance Index for Diagnosis of Pulmonary Embolism in Patients With Echocardiographic Signs of Pulmonary Hypertension I read with great interest the report by Hsiao et al,1 which confirmed that the right ventricular (RV) myocardial performance index (MPI) was significantly higher in patients with pulmonary embolism (PE) than in others; that patients without PE had concordant changes in the RV and left ventricular (LV) MPIs; that in patients with acute PE, the RV MPI became higher but the LV MPI was relatively constant; that using the RV MPI divided by the LV MPI (the V index), PE could be distinguished in patients with echocardiographic signs of pulmonary hypertension (PH); and that by receiver-operating characteristic curve analysis, a V index ⬎1.2 identified PE with sensitivity of 82% and specificity of 83%, suggesting that the V index is a useful parameter to assess the possibility of PE in patients with echocardiographic signs of PH. The methods and interpretation of the results, however, raise several concerns.
Hsiao et al1 described in the abstract that 100 patients with echocardiographic signs of PH were enrolled in this study after informed consent was obtained and that PE was found in 50 patients by multidetector-row computed tomography of the chest. That is to say, 50 patients with PE (the PE group) all had echocardiographic signs of PH, defined by the investigators as (1) pulmonary arterial systolic pressure (PASP) ⬎40 mm Hg and (2) evidence of RV dilation or dysfunction. However, the average value of PASP in the PE group was 40 mm Hg in Table 1, were the PASP value of 50 patients all ⬎40 mm Hg which were not well described in the study by Hsiao et al1? If not, was there a contrary description or slip of the pen between the abstract and Table 1? A mechanism of ventricular interaction in PH can be described as follows2: (1) at rest, cardiac function is characterized by RV systolic overload due to PH and diastolic overload with tricuspid regurgitation, whereas the left ventricle has diastolic underloading and reduced compliance, LV systolic performance remains preserved; and (2) during exercise, RV systolic performance further worsens, with a reduction in stroke volume and the ejection fraction, and consequently LV stroke volume decreases because of underfilling, and heart rate becomes the mechanism by which cardiac output increases. It is likely that the extent of RV and LV dysfunction was well related to pulmonary arterial pressure. In Hsiao et al’s study,1 PASP in the PH group was significantly higher than that in the PE group, which could have caused the discordance of the changes in LV and RV dysfunction and further affected the sensitivity and specificity of the V index identifying PE. Therefore, the sensitivity and specificity of the V index in identifying PE with the same level of PASP in PH and PE needs to be studied further. In addition, in Hsiao et al’s study,1 the duration of PH in the PH and PE groups was not well described, which could have caused the discordance of the changes in LV and RV dysfunction and further affected the sensitivity and specificity of the V index in identifying PE. This issue requires further study. Ze-Zhou Song, MM Hangzhou, China 5 March 2007
1. Hsiao SH, Yang SH, Wang WC, Lee CY, Lin SK, Liu CP. usefulness of regional myocardial performance index to diagnose pulmonary embolism in patients with echocardiographic signs of pulmonary hypertension. Am J Cardiol 2006; 98:1652–1655. 2. Nootens M, Wolfkiel CJ, Chomka EV, Rich S. Understanding right and left ventricular systolic function and interactions at rest and with exercise in primary pulmonary hypertension. Am J Cardiol 1995;75:374 –377. doi:10.1016/j.amjcard.2007.03.012
A Novel Method of Two-Dimensional Echocardiographic Tracking I read with great interest the study by Ogawa et al,1 which confirmed that there was excellent agreement between the 2-dimensional tracking and manual methods for left ventricular (LV) wall thickness (r ⫽ 0.99) and percentage wall thickness (%WT) (r ⫽ 0.97); that the mean differences in LV wall thickness and %WT were 0.1 ⫾ 0.4 mm and 0 ⫾ 5.4%, respectively; and that average %WT was significantly decreased in regions of hypokinetic or akinetic wall motion compared with those of normal motion (18 ⫾ 4% and 4 ⫾ 4% vs 39 ⫾ 10%, p ⬍0.001), suggesting that this 2-dimensional tracking method can be used for the noninvasive, automated quantitation of LV wall motion in 2-dimensional echocardiography. The methods and interpretation of the results, however, raise several concerns. It is well known that segmental myocardial motion is complex, with 3 separate components: radial motion, longitudinal motion, and rotational motion. In addition, segmental myocardial motion could be affected by cardiac global motion and adjacent myocardial motion. In the study by Ogawa et al,1 however, segmental LV wall motion, including normokinetic, hypokinetic, akinetic, and dyskinetic, was evaluated by means of visual estimation by an experienced examiner without knowledge of the study patients. Therefore, the visual estimation of regional wall motion could be more subjective, less reproducible, and even more inaccurate, even though it was performed by an experienced examiner. It is well known that the accuracy of ultrasonic strain and strain rate measurements to evaluate segmental myocardial motion has been validated, and ranges of normal values have been recently established in healthy volun-