Luigi Meloni

Validation of a new noninvasive method (contrast-enhanced transthoracic second harmonic echo Doppler) for the evaluation of coronary flow reserve: Comparison with intracoronary Doppler flow wire

OBJECTIVES We tested the hypothesis that coronary flow reserve (CFR) in the left anterior descending coronary artery (LAD) as assessed by a new noninvasive method (contrast-enhanced transthoracic second harmonic echo Doppler) is in agreement with CFR measurements assessed by intracoronary Doppler flow wire. BACKGROUND Contrast-enhanced transthoracic second harmonic echo Doppler is a novel noninvasive method to detect blood flow velocity and reserve in the LAD. However, it has not yet been validated versus a gold-standard method. METHODS Twenty-five patients undergoing CFR assessment in the LAD by Doppler flow wire were also evaluated by contrast-enhanced transthoracic Doppler to record blood flow in the distal LAD at rest and during hyperemia obtained by adenosine i.v. infusion. In five patients CFR was evaluated twice (before and after angioplasty). RESULTS As a result of the combined use of i.v. contrast and second harmonic Doppler technology, feasibility in assessing coronary flow reserve equaled 100%. The agreement between the two methods was high. In fact, in all but five patients the maximum difference between the two CFR measurements was 0.38. Overall, the prediction (95%) interval of individual differences was -0.69 to +0.72. Reproducibility of CFR measurements was also high. The limits of the agreement (95%) between the two measurements were -0.32 to +0.32. CONCLUSIONS Coronary flow reserve in the LAD as assessed by contrast-enhanced transthoracic echo Doppler along with harmonic mode concurs very closely with Doppler flow wire CFR measurements. This new noninvasive method allows feasible, reliable and reproducible assessment of CFR in the LAD.

Effects of Acute Myocardial Ischemia on Intramyocardial Contraction Heterogeneity A Study Performed with Ultrasound Integrated Backscatter During Transesophageal Atrial Pacing

BACKGROUND [corrected] Subendocardial thickening is greater than subepicardial thickening and acute myocardial ischemia mainly impairs the former. Integrated backscatter cyclic variations (IBScv) reflect regional myocardial contractility and are blunted during myocardial ischemia. We hypothesized that stress-induced myocardial ischemia mainly affects subendocardial IBScv. METHODS AND RESULTS Multiplane transesophageal echocardiography and simultaneous atrial pacing were performed in 12 patients without coronary artery disease (CAD) and in 25 with significant CAD. In a transgastric 2-chamber view, we calculated IBScv in subendocardium and subepicardium and a heterogeneity index, both at rest and at peak-pacing. In 27 myocardial segments of patients with normal coronary arteries, and in 16 myocardial segments supplied by coronary artery without significant stenosis in patients with CAD, there was a transmural gradient of IBScv at rest and the heterogeneity index did not change during all the protocol steps. In the 53 myocardial segments related to a significantly narrowed coronary artery, the transmural gradient of IBScv, present at rest, significantly decreased at peak-pacing because of subendocardial blunting, but promptly recovered 5 seconds after pacing interruption. Moreover, the myocardial thickening at rest and peak pacing correlated with the subendocardial IBScv behavior and not with the subepicardial one. CONCLUSIONS IBScv are greater in the subendocardium than in the subepicardium. Atrial pacing stress test does not affect IBScv in segments supplied by nonstenotic coronary arteries, whereas it affects segments supplied by diseased coronary arteries, blunting exclusively subendocardial IBScv. Heterogeneity of IBScv intramyocardial changes caused by stress-induced ischemia must be taken into account when using IBScv for investigating myocardial ischemia.

Non-invasive coronary flow reserve is correlated with microvascular integrity and myocardial viability after primary angioplasty in acute myocardial infarction

Objective: To test whether preserved coronary flow reserve (CFR) two days after reperfused acute myocardial infarction (AMI) is associated with less microvascular dysfunction (“ no-reflow” phenomenon) and is predictive of myocardial viability. Design: 24 patients with anterior AMI underwent CFR assessment in the left anterior descending coronary artery (LAD) with transthoracic echocardiography and myocardial contrast echocardiography (MCE) 48 h after primary angioplasty in the LAD (mean 4 (SD 2) and 3 (1) days, respectively). Low-dose dobutamine echocardiography was performed 6 (3) days after AMI and follow-up echocardiography at three months. Results: No-reflow extent was greater in patients with impaired CFR (< 2.5) than in those with preserved CFR (> 2.5) (55 (35)% v 11 (25)%, p < 0.001). MCE reflow was more common in patients with preserved CFR (8/12) than in those with reduced CFR (1/12, p < 0.05). Wall motion score index in the LAD territory (A-WMSI) was similar at the first echocardiography (2.14 (0.39) v 2.32 (0.47), NS), although it was better in patients with preserved CFR at dobutamine (1.38 (0.45) v 1.97 (0.67), p < 0.05) and follow-up echocardiography (1.36 (0.40) v 1.97 (0.64), p < 0.05). An inverse correlation was found between CFR and A-WMSI at dobutamine and follow-up echocardiography (r  =  −0.49, p  =  0.016 and r  =  −0.55, p  =  0.005) and between MCE and A-WMSI at dobutamine and follow-up echocardiography (r  =  −0.75, p < 0.001 and r  =  −0.75, p < 0.001). By multivariate analysis MCE reflow remained the only predictor of recovery at both dobutamine and follow-up echocardiography (odds ratio 1.06, 95% CI 1 to 1.1, p  =  0.009). Conclusion: CFR is inversely correlated with the extent of microvascular dysfunction at MCE two days after reperfused AMI. CFR and MCE reflow early after AMI are correlated with myocardial viability at follow up.

Regurgitant Flow of Mitral Valve Prostheses: An Intraoperative Transesophageal Echocardiographic Study

To assess the regurgitant characteristics of mitral biologic and mechanical prostheses immediately after implantation, intraoperative transesophageal echocardiography was performed in 27 patients, aged 32 to 69 years, undergoing open-heart surgery for rheumatic heart disease (n = 19), mitral valve prolapse (n = 3), malfunctioning prostheses (n = 3), or periprosthetic leaks (n = 2). The prostheses included 13 biologic (Carpentier-Edwards) and 14 mechanical valves (five Starr-Edwards, five Medtronic-Hall, and four Bjork-Shiley). Physiologic transvalvular regurgitant flow was detected in both biologic and mechanical prostheses. The spatial extent of the regurgitant jets was usually greater in the mechanical than in the biologic valves, and systolic jets, characteristic of each type of valve, were visualized consistently. Trivial periprosthetic jets (PPJs) were observed in many implanted valves (14/27). The median maximal jet area was 0.46 cm2 (range 0.1 to 1.5 cm2). Cardiopulmonary bypass was reinstituted in two patients. In one patient a PPJ was judged extensive enough (area 3.6 cm2) to warrant surgical revision of the implant, but no dehiscence was found. In the other patient a turbulent PPJ (area 5.5 cm2) was associated with a 0.5 cm dehiscence at the surgical inspection. In conclusion, (1) all mitral prostheses exhibit physiologic transvalvular regurgitation, (2) trivial mitral PPJ is a common finding in newly implanted mitral valves and does not require the revision of the implant, and (3) further experience based on larger series of patients is required to determine the maximal acceptable size of a mitral PPJ detected by intraoperative transesophageal echocardiography.

Detection of microbubbles released by oxygenators during cardiopulmonary bypass by intraoperative transesophageal echocardiography

Abstract Despite the improvements in cardiopulmonary bypass techniques, release of microbubbles in the systemic arterial circulation still occurs. It is believed that microemboli, prolonged arterial hypotension, defective cerebral blood flow autoregulation and nonpulsatile flow during cardiopulmonary bypass play a role in determining neurologic damage after cardiopulmonary bypass.1,2 Gaseous and particulate microemboli may originate from the pump-oxygenator system as well as from the cardiac chambers and pulmonary veins.1,3 In this study, transesophageal echocardiography was used to detect microbubbles reaching the arterial circulation during cardiopulmonary bypass. Two different types of oxygenators (bubbles and hollow fibers) were used to assess differences in their production of microbubbles.

Prognostic impact of coronary microcirculation abnormalities in systemic sclerosis: a prospective study to evaluate the role of non-invasive tests

IntroductionMicrocirculation dysfunction is a typical feature of systemic sclerosis (SSc) and represents the earliest abnormality of primary myocardial involvement. We assessed coronary microcirculation status by combining two functional tests in SSc patients and estimating its impact on disease outcome.MethodsForty-one SSc patients, asymptomatic for coronary artery disease, were tested for coronary flow velocity reserve (CFR) by transthoracic-echo-Doppler with adenosine infusion (A-TTE) and for left ventricular wall motion abnormalities (WMA) by dobutamine stress echocardiography (DSE). Myocardial multi-detector computed tomography (MDCT) enabled the presence of epicardial stenosis, which could interfere with the accuracy of the tests, to be excluded. Patient survival rate was assessed over a 6.7- ± 3.5-year follow-up.ResultsNineteen out of 41 (46%) SSc patients had a reduced CFR (≤2.5) and in 16/41 (39%) a WMA was observed during DSE. Furthermore, 13/41 (32%) patients showed pathological CFR and WMA. An inverse correlation between wall motion score index (WMSI) during DSE and CFR value (r = -0.57, P <0.0001) was observed; in addition, CFR was significantly reduced (2.21 ± 0.38) in patients with WMA as compared to those without (2.94 ± 0.60) (P <0.0001). In 12 patients with abnormal DSE, MDCT was used to exclude macrovasculopathy. During a 6.7- ± 3.5-year follow-up seven patients with abnormal coronary functional tests died of disease-related causes, compared to only one patient with normal tests.ConclusionsA-TTE and DSE tests are useful tools to detect non-invasively pre-clinical microcirculation abnormalities in SSc patients; moreover, abnormal CFR and WMA might be related to a worse disease outcome suggesting a prognostic value of these tests, similar to other myocardial diseases.

Echocardiographic assessment of aortic valve replacement with stentless porcine xenografts

Stentless porcine xenografts (SPXs) implanted in the aortic position have potential hemodynamic advantages over traditional valve prostheses because of the lack of a rigid stent. Twenty-four patients (mean age 59 years) who underwent aortic valve replacement with SPXs were studied by echocardiography early after and 26 +/- 10 months (range 8 to 40) after operation. Peak and mean gradients, as well as aortic valve area, did not change significantly from baseline (16.3 +/- 8 and 9.8 +/- 5.6 mm Hg, and 1.78 +/- 0.63 cm2, respectively) to follow-up study (12.5 +/- 5 and 7.7 +/- 3 mm Hg, and 1.8 +/- 0.65 cm2, respectively). At baseline, color flow Doppler imaging showed aortic valve regurgitation where the leaflets coapted centrally in 17 of 24 patients (trivial, n = 14; mild, n = 3). Besides the central leak, paravalvular regurgitation was seen in 4 patients (trivial, n = 3; mild, n = 1). At follow-up, 18 of 24 patients had aortic valve regurgitation (trivial, n = 11; mild, n = 6; and moderate, n = 1). New valvular regurgitation (graded as trivial, n = 2; mild, n = 2; and moderate, n = 1) was detected in 5 patients, and new paravalvular regurgitation (graded as mild) developed in 1 patient. Two patients underwent repeat operation for valve-related complications: (1) rupture of a valve cusp with acute pulmonary edema, and (2) fibrotic stenosis of the left coronary ostium with unstable angina. In conclusion, this study demonstrates good hemodynamic performance of the SPX in the aortic position.(ABSTRACT TRUNCATED AT 250 WORDS)

Early Noninvasive Evaluation of Coronary Flow Reserve after Angioplasty in the Left Anterior Descending Coronary Artery Identifies Patients at High Risk of Restenosis at Follow-Up

BACKGROUND Coronary restenosis is the most important clinical limitation after percutaneous coronary intervention (PCI), and coronary flow reserve (CFR) is reduced in the presence of significant coronary stenosis. This study evaluated whether detection of early reduction of Doppler echocardiographically derived CFR in the left anterior descending coronary artery can identify patients at high risk for developing restenosis after successful PCI. METHODS Doppler echocardiographically derived CFR was studied in 124 consecutive patients at 1-month and 6-month follow-up after PCI in the left anterior descending coronary artery, together with coronary angiography. RESULTS Restenosis was detected in 39 angiographic examinations (group A) and no coronary restenosis in the remaining 85 (group B) at 6 months. At 1 month, CFR was reduced in group A compared with group B (P < .0001), and a significant reduction of CFR in group A (P < .0001) but not in group B (P = .89) was detected at 6 months. CFR ≤ 2.5 at 1 month was 67% sensitive and 87% specific for predicting significant restenosis, with positive and negative predictive values of 67% and 87%, respectively. CONCLUSIONS CFR ≤ 2.5 detected 1 month after PCI in the left anterior descending coronary artery has the potential to identify patients at higher risk for developing coronary restenosis and indicates the need for close clinical follow-up.

Evaluation of cardiac functional abnormalities in systemic sclerosis by dobutamine stress echocardiography: a myocardial echostress scleroderma pattern.

In this study, we investigate the possibility of detecting, by dobutamine stress echocardiography (DSE), the presence of early or subclinical myocardial functional changes in patients with systemic sclerosis (SSc) without symptoms of ischaemic cardiac involvement.

Admission hyperglycemia in acute myocardial infarction: possible role in unveiling patients with previously undiagnosed diabetes mellitus

Aim The aim of this study was to investigate the relationship between admission plasma glucose levels and abnormal glucose metabolism in patients with acute myocardial infarction (AMI) without a previous diagnosis of diabetes mellitus. Methods A total of 285 nondiabetic patients admitted with AMI were screened for glucometabolic disorders by using fasting glucose measurements during hospital stay or an oral glucose tolerance test on discharge. Patients diagnosed as having diabetes mellitus were followed-up for a mean of 60 ± 33 months in order to confirm the diagnosis. Results There was a graded relationship between admission glucose levels and the prevalence of newly detected diabetes mellitus (group 1, <140 mg/dl: 12%; group 2, ≥140 < 200 mg/dl: 40%; group 3, ≥200 mg/dl: 70.3%; P < 0.0001). The admission glucose level of at least 144 mg/dl was the best predictor of newly detected diabetes mellitus during hospitalization (area under the curve 0.78, P = 0.0001). In multivariable analysis, patients with admission hyperglycemia had greater odds of having newly detected diabetes mellitus (odds ratio 6.6, 95% confidence interval 2.7–16.3, P = 0.0001). Diabetes mellitus was confirmed in the long-term follow-up in 78% of patients diagnosed as having diabetes mellitus during hospitalization. Conclusion Our finding suggests a relationship between admission glucose and previously undetected diabetes mellitus in nondiabetic patients presenting AMI. Acute hyperglycemia may help to identify high-risk patients for diabetes mellitus, who should be screened initially for glucometabolic disorders, then closely monitored and appropriately treated to improve outcome.