Prognostic value of dobutamine stress myocardial perfusion echocardiography in patients with known or suspected coronary artery disease and normal left ventricular function

<div><p>Objective</p><p>We sought to determine the prognostic value of qualitative and quantitative analysis obtained by real-time myocardial perfusion echocardiography (RTMPE) in patients with known or suspected coronary artery disease (CAD).</p><p>Background</p><p>Quantification of myocardial blood flow reserve (MBFR) in patients with CAD using RTMPE has been demonstrated to further improve accuracy over the analysis of wall motion (WM) and qualitative analysis of myocardial perfusion (QMP).</p><p>Methods</p><p>From March 2003 to December 2008, we prospectively studied 168 patients with normal left ventricular function (LVF) who underwent dobutamine stress RTMPE. The replenishment velocity reserve (β) and MBFR were derived from RTMPE. Acute coronary events were: cardiac death, myocardial infarction and unstable angina with need for urgent coronary revascularization.</p><p>Results</p><p>During a median follow-up of 34 months (5 days to 6.9 years), 17 acute coronary events occurred. Abnormal β reserve in ≥2 coronary territories was the only independent predictor of events hazard ratio (HR) = 21, 95% CI = 4.5–99; p<0.001). Both, abnormal β reserve and MBFR added significant incremental value in predicting events over qualitative analysis of WM and MP (χ2 = 6.6 and χ2 = 24.6, respectively; p = 0.001 and χ2 = 6.6 and χ2 = 15.5, respectively; p = 0.012, respectively). When coronary angiographic data was added to the multivariate analysis model, β reserve remained the only predictor of events with HR of 21.0 (95% CI = 4.5–99); p<0.001.</p><p>Conclusion</p><p>Quantitative dobutamine stress RTMPE provides incremental prognostic information over clinical variables, qualitative analysis of WM and MP, and coronary angiography in predicting acute coronary events.</p></div

Prognostic value of dobutamine stress myocardial perfusion echocardiography in patients with known or suspected coronary artery disease and normal left ventricular function - Fig 3

<p>Apical four-chamber view imagin of a 67 year-old man with normal wall motion and qualitative myocardial perfusion at rest (<b>A)</b>. <b>(B)</b> During dobutamine-stress, it was observed apical dyskinesis and marked perfusion defect (arrow). <b>(C)</b> Acoustic intensity curves at rest and during stress demonstrated a low β reserve. <b>(D)</b> Coronary angiography demonstrated significant coronary artery disease. Patient had event after 8 months of echocardiography. LAD-left anterior descending artery, LCx- left circumflex artery, LMA- left marginal artery.</p

Allogeneic pASC transplantation in humanized pigs attenuates cardiac remodeling post-myocardial infarction

<div><p>Cell therapy repair strategies using adult mesenchymal stromal cells have shown promising evidence to prevent cardiac deterioration in rodents even in the absence of robust differentiation of the cells into cardiomyocytes. We tested whether increasing doses of porcine adipose-tissue derived mesenchymal stem cells (pASCs) increase cardiac tissue perfusion in pigs post-myocardial infarction (MI) receiving angiotensin-converting-enzyme inhibitor (ACE inhibitors) and Beta-blockers similarly to patients. Female pigs were subjected to MI induction by sponge permanent occlusion of left circumflex coronary artery (LCx) generating approximately 10% of injured LV area with minimum hemodynamic impact. We assessed tissue perfusion by real time myocardial perfusion echocardiography (RTMPE) using commercial microbubbles before and following pASCs treatment. Four weeks after the occlusion of the left circumflex artery, we transplanted placebo or pASCs (1, 2 and 4x10⁶ cells/Kg BW) into the myocardium. The highest dose of pASCs increased myocardial vessel number and blood flow in the border (56% and 3.7-fold, respectively) and in the remote area (54% and 3.9-fold, respectively) while the non-perfused scar area decreased (up to 38%). We also found an increase of immature collagen fibers, although the increase in total tissue collagen and types I and III was similar in all groups. Our results provide evidence that pASCs-induced stimulation of tissue perfusion and accumulation of immature collagen fibers attenuates adverse remodeling post-MI beyond the normal beneficial effects associated with ACE inhibition and beta-blockade.</p></div

Incremental value of Coronary Angiography (CA), abnormal Myocardial Perfusion (MP), abnormal Myocardial Blood Flow Reserve (MBFR) (A) and abnormal β reserve (B) over abnormal Wall Motion (WM) using a Cox model.

<p>Incremental value of Coronary Angiography (CA), abnormal Myocardial Perfusion (MP), abnormal Myocardial Blood Flow Reserve (MBFR) (A) and abnormal β reserve (B) over abnormal Wall Motion (WM) using a Cox model.</p

Kaplan-Meier curves of patients according the results of Wall Motion (WM) (A) and qualitative Myocardial Perfusion (MP) (B).

<p>Kaplan-Meier curves of patients according the results of Wall Motion (WM) (A) and qualitative Myocardial Perfusion (MP) (B).</p

Kaplan-Meier curves of patients according the results of β reserve (A) and MBFR (B).

<p>Kaplan-Meier curves of patients according the results of β reserve (A) and MBFR (B).</p

Characteristics of patients according to the results of βreserve and MBFR.

<p>Characteristics of patients according to the results of βreserve and MBFR.</p