Myocardial Infarction incidence during national lockdown in two French provinces unevenly affected by COVID-19 outbreak: An observational study.

BACKGROUND: A reduction of admission for MI has been reported in most countries affected by COVID-19. No clear explanation has been provided. METHODS: To report the incidence of myocardial infarction (MI) admission during COVID-19 pandemic and in particular during national lockdown in two unequally affected French provinces (10-million inhabitants) with a different media strategy, and to describe the magnitude of MI incidence changes relative to the incidence of COVID-19-related deaths. A longitudinal study to collect all MIs from January 1 until May 17, 2020 (study period) and from the identical time period in 2019 (control period) was conducted in all centers with PCI-facilities in northern "Hauts-de-France" province and western "Pays-de-la-Loire" Province. The incidence of COVID-19 fatalities was also collected. FINDINGS: In "Hauts-de-France", during lockdown (March 18-May 10), 1500 COVID-19-related deaths were observed. A 23% decrease in MI-IR (IRR=0.77;95%CI:0.71-0.84, p<0.001) was observed for a loss of 272 MIs (95%CI:-363,-181), representing 18% of COVID-19-related deaths. In "Pays-de-la-Loire", 382 COVID-19-related deaths were observed. A 19% decrease in MI-IR (IRR=0.81; 95%CI=0.73-0.90, p<0.001) was observed for a loss of 138 MIs (95%CI:-210,-66), representing 36% of COVID-19-related deaths. While in "Hauts-de-France" the MI decline started before lockdown and recovered 3 weeks before its end, in "Pays-de-la-Loire", it started after lockdown and recovered only by its end. In-hospital mortality of MI patients was increased during lockdown in both provinces (5.0% vs 3.4%, p=0.02). INTERPRETATION: It highlights one of the potential collateral damages of COVID-19 outbreak on cardiovascular health with a dramatic reduction of MI incidence. It advocates for a careful and weighted communication strategy in pandemic crises. FUNDING: The study was conducted without external funding.

Usefulness of two-dimensional longitudinal strain pattern to predict left ventricular recovery and in-hospital complications after acute anterior myocardial infarction treated successfully by primary angioplasty.

BACKGROUND: The aim of this study was to test the usefulness of two-dimensional longitudinal strain pattern in segments with wall motion abnormalities to predict left ventricular recovery and in-hospital cardiac events as well as coronary microvascular impairment (CMI) in patients with recent acute anterior myocardial infarction. METHODS: Forty-nine consecutive patients with acute myocardial infarction (mean age, 59 ± 13 years) treated successfully with primary coronary angioplasty prospectively underwent transthoracic Doppler echocardiography 24 hours after angioplasty and during follow-up (6 months). A two-dimensional strain analysis, including measurement of the duration of systolic lengthening expressed as a percentage of systolic duration (SL % duration), the lengthening-to-shortening ratio, the postsystolic shortening index in segments with wall motion abnormalities, and global longitudinal strain and left anterior descending coronary artery territory strain, was performed. Cardiac events were defined as a composite of death, reinfarction, and heart failure. CMI was assessed noninvasively by transthoracic Doppler left anterior descending coronary artery investigation <24 h after angioplasty and was defined as coronary flow velocity reserve < 1.7 and/or a no-reflow pattern (mean coronary flow velocity reserve, 1.8 ± 0.6 in the whole group). RESULTS: At the segmental level, SL % duration, lengthening-to-shortening ratio, and postsystolic shortening index were correlated with recovery (defined as normalization of wall motion abnormalities), whereas in multivariate analysis, only SL % duration independently predicted recovery (threshold level, 40%; area under the curve, 0.76; P < .01). At the patient level, in univariate analysis, SL % duration, global longitudinal strain, left anterior descending coronary artery territory strain, and troponin peak were correlated with recovery (defined as an absolute improvement of left ventricular ejection fraction of >5%). In multivariate analysis, SL % duration was independently related to recovery (area under the curve, 0.78; P < .01). Furthermore, SL % duration was independently linked to cardiac events (n = 13) and CMI (n = 24) (P < .01 for all). CONCLUSIONS: In patients with AMI treated by primary angioplasty, two-dimensional strain predicts left ventricular recovery independently of more traditional parameters and is independently linked to cardiac events and CMI.

Relationship between acute strain pattern and recovery in tako-tsubo cardiomyopathy and acute anterior myocardial infarction: a comparative study using two-dimensional longitudinal strain.

After acute-anterior myocardial infarction (AMI), left ventricular (LV) viable myocardial segments show some degree of active deformation (longitudinal shortening) despite wall motion abnormalities (WMA). Tako-tsubo cardiomyopathy (TTC) is characterized by myocardial stunning; however, it is unclear whether in TTC the strain pattern mimics AMI. To compare the strain-pattern in TTC and AMI using the 2D-longitudinal strain by speckle-tracking in segments with WMA, and its relationship with recovery of function at follow-up. 21 consecutive patients with typical TTC and 21 age-matched AMI patients treated by primary angioplasty had an analysis of LV-longitudinal strain at the acute-phase and at follow-up (1 and 6 months later for TTC and AMI respectively). The recovery of a segment was defined as normal wall motion at follow-up. Among the 706 analyzable LV-segments at the acute-phase, 406 had WMA (TTC 229, AMI 177). At follow-up, total recovery was observed for 45 % segments in AMI and 100 % in TTC, (p < 0.01). At the acute phase, systolic lengthening duration (47 ± 43 vs. 18 ± 33 %) and amplitude (0.25 ± 0.29 vs. 0.09 ± 0.19) and post systolic shortening (67 ± 53 vs. 39 ± 38 %) were higher in TTC, when compared to AMI-recovery (all, p < 0.01). In AMI, systolic lengthening duration was an independent predictor of poor recovery in multivariate analysis, linked to segmental longitudinal strain at follow-up (all, p ≤ 0.01). Furthermore, among the 57 % of segments exhibiting any systolic lengthening duration in AMI, only » recovered, versus 62 % of such segments in TTC with 100 % recovery (p < 0.001). The systolic passive motion which is closely and inversely linked to recovery in AMI is paradoxically frequent and severe in TTC. This suggests that myocardial stunning in TTC and AMI is different according to longitudinal strain.

Non-invasive detection of tako-tsubo cardiomyopathy vs. acute anterior myocardial infarction by transthoracic Doppler echocardiography.

AIMS: Typical tako-tsubo cardiomyopathy (TTC) mimics acute anterior myocardial infarction (AMI) and the differential diagnosis is challenging before coronary angiography (CA) is performed; it demonstrates reduced or absent antegrade flow in the left anterior descending artery (LAD) in AMI, whereas there is no such flow limiting in TTC. At the acute phase, we tested the usefulness of the distal LAD flow visualization by transthoracic Doppler echocardiography (TDE) to distinguish between these two diseases. For this purpose, we prospectively enrolled 28 consecutive patients with TTC (75 ± 10 years, 93% females) who were compared with 28 consecutive patients with AMI treated successfully by primary angioplasty (66 ± 12 years, 79% females). All the patients underwent the assessment of the distal LAD flow just before CA, using colour and pulsed-wave TDE. In addition, the symmetric involvement of wall motion abnormalities (WMAs) based on the extent of the disease far beyond one coronary territory in TTC was searched by TDE. Non-invasive coronary flow reserve (CFR) by TDE, in the distal LAD, was also performed within 1 day after admission. RESULTS: Before CA, the distal LAD flow was visible in 38 of 56 cases (68%) in the whole population, in all cases with TTC and in 10 cases with AMI (36%). The sensitivity (Se) and specificity (Sp) of the LAD flow visualization for the diagnosis of TTC were 100 and 64%, respectively, with a diagnostic accuracy of 82%. In comparison, the pattern of WMA yielded a Se of 75% and Sp of 86%, and a diagnostic accuracy of 80%. With the combination of both tools, the Se and Sp to detect TTC were 75 and 96% respectively, with a diagnostic accuracy of 86%. After CA, the acute CFR was less severely impaired in the TTC group when compared with the AMI group (2.2 ± 0.5 vs. 1.7 ± 0.6, P < 0.01) despite a worse LV systolic dysfunction. CONCLUSION: Non-invasive evaluation of the distal LAD flow could be helpful to differentiate TTC from AMI, and its combination with the pattern of WMA improved slightly its diagnostic accuracy. Furthermore, the acute CFR is less severely impaired in TTC compared with AMI despite poorer LV systolic dysfunction, suggesting that other mechanisms than direct microcirculatory damage are also involved in the pathogenesis of WMAs in TTC.

Factors associated with noninvasive coronary flow reserve in severe aortic stenosis.

BACKGROUND: Coronary flow reserve (CFR) is progressively impaired with aortic stenosis (AS) severity. However, there is a broad range of CFR in patients with severe AS, and the factors responsible for this variability are weakly characterized. The aim of this study was to assess the correlates of noninvasive CFR in patients with severe AS (≤1 cm(2) or ≤0.6 cm(2)/m(2)) and preserved left ventricular (LV) ejection fractions (LVEFs) (>50%). METHODS: Sixty-six consecutive patients (mean age, 74 ± 11 years; 31 women; mean LVEF, 69 ± 10%) with isolated severe AS (mean, 0.75 ± 0.2 cm(2) and 0.42 ± 0.1 cm(2)/m(2)), without coronary artery disease, underwent prospectively Doppler transthoracic echocardiography including CFR measurement in the distal part of the left anterior descending coronary artery (LAD) with intravenous adenosine infusion (140 µg/kg/min over 2 min). CFR was defined as hyperemic peak LAD flow velocity divided by baseline flow velocity. Twenty controls matched for age and gender served as a comparative group. Plasma N-terminal pro-brain natriuretic peptide (NT-proBNP) was also assessed. RESULTS: Compared with controls, patients with AS had higher baseline LAD flow velocities (36 ± 11 vs 27 ± 6 cm/sec, P < 0.01), lower hyperemic LAD flow velocities (80 ± 20 vs 89 ± 18 cm/sec, P = .09), and consequently lower CFR (2.3 ± 0.7 vs 3.3 ± 0.7, P < .01). In patients with AS, there were significant inverse correlations between CFR and age, E/e', indexed LV mass, NT-proBNP, pulmonary artery systolic pressure (PASP), baseline LV rate-pressure product, heart rate, and indexed left atrial volume and a significant positive correlation between CFR and LVEF (all P values < .05). Furthermore, compared with patients with asymptomatic AS (n = 22), those with symptomatic AS had more severely impaired CFR (2.15 ± 0.6 vs 2.7 ± 0.65), and higher NT-proBNP values (all P values < .05). In multivariate analysis, NT-proBNP, PASP, and LV rate-pressure product were the main independent correlates of CFR (all P values ≤ .01), and PASP was independently predicted by E/e' and indexed left atrial volume (all P values < .01). CONCLUSIONS: In patients with severe AS and preserved LVEFs, there is a relatively broad range of CFR values. CFR is more severely impaired in patients with symptomatic AS and is mainly linked with NT-proBNP, a surrogate of increased LV wall stress, workload as measured by LV rate-pressure product, and PASP.

Assessment of left ventricular twist mechanics in Tako-tsubo cardiomyopathy by two-dimensional speckle-tracking echocardiography.

AIMS: To assess left ventricular (LV) twist mechanics in patients with Tako-tsubo cardiomyopathy (TTC). METHODS AND RESULTS: Two-dimensional strain and LV twist by speckle-tracking echocardiography was performed in 17 consecutive patients with typical TTC according to the Mayo clinic criteria [78 ± 8 years, 88% women, and mean left ventricular ejection fraction (LVEF) 45 ± 10%], at the acute phase (within 24 h after admission) and after recovery (1 month later). Seventeen control (C) patients matched for age and sex (mean LVEF 70 ± 7%), and 17 patients with acute anterior myocardial infarction (MI) treated by successful primary angioplasty 24 h before, matched for LVEF, age, and sex, were compared with TTC patients. LV twist was assessed using the parasternal basal and apical short-axis planes, and defined as the net difference in degrees of apical (Ar) and basal rotation (Br). Peak systolic and early diastolic, apical (As and Ad) and basal (Bs and Bd) rotation rate, and LV twisting rate (TR) and untwisting rate (UR) (in °/s) were derived from rotational and twist curves. The time sequences were normalized to the percentage of systolic duration. At the acute phase, Ar, As, Ad, Bs, LV twist (10 ± 9° vs. 23 ± 6°), LV TR, and LV UR were significantly impaired in patients with TTC when compared with controls (all, P < 0.05). Patients with MI displayed intermediate values (P = NS vs. TTC, and P < 0.05 vs. C). However, in the subgroup of patients with electrocardiogram ST-segment elevation at presentation (n = 12 TTC and 17 MI), several LV twist mechanics parameters were significantly reduced in TTC patients when compared with MI patients, LV twist, and LV TR being the most significant factors (all, P≤ 0.01). Abnormal reversed Ar (clockwise when seen from the apex) was seen in three patients (18%) with TTC vs. none in the other groups. A significant correlation between LV twist and LVEF, LV volumes, wall motion score index, and plasma NT-pro BNP was observed in the TTC group (all, P < 0.05). At follow-up, LV twist mechanics improved significantly in TTC patients (all, P < 0.05 vs. acute phase), who had final values similar to C (all, P = NS), whereas the magnitude of improvement was lower in MI patients (P ≤ 0.05 vs. TTC). CONCLUSION: LV twist mechanics is significantly impaired in patients with TTC mainly due to a severe reduction in apical function and is entirely reversible. Furthermore, in the subgroup of patients with ST-segment elevation, the early post-admission evaluation of LV twist mechanics is more severely impaired in TTC when compared with MI.

Comparison between non-invasive coronary flow reserve and fractional flow reserve to assess the functional significance of left anterior descending artery stenosis of intermediate severity.

BACKGROUND: Assessment of the functional significance of left anterior descending coronary artery (LAD) stenosis of intermediate severity (50%-70% diameter stenosis) is challenging. The aim of this study was to compare the value of noninvasive coronary flow reserve (CFR) with that of invasive fractional flow reserve (FFR) in the setting of LAD stenosis of angiographic intermediate severity. METHODS: Fifty stable consecutive patients (mean age, 63 ± 13 years; 11 women; mean left ventricular ejection fraction, 61 ± 10%) with angiographic proximal LAD stenoses of intermediate severity (55.5 ± 5% diameter stenosis on quantitative coronary angiography), no previous anterior myocardial infarction, and various vascular risk factors were prospectively studied. They underwent FFR assessment with intracoronary bolus adenosine (150 µg), and CFR assessment using intravenous adenosine (140 µg/kg/min over 2 min) in the distal part of the LAD on the same day in nearly all patients. CFR was defined as hyperemic peak diastolic LAD flow velocity divided by baseline flow velocity (normal value >2), and FFR was defined as distal pressure divided by mean aortic pressure during maximal hyperemia (normal value >0.8). RESULTS: The mean FFR and CFR were 0.84 ± 0.07 and 2.7 ± 0.75, respectively, in the whole population. Concordant results between FFR and CFR were seen in 44 patients (88%) and discordant results in six patients (12%). There was a significant correlation between CFR and FFR (r = 0.59, P < .01). A better correlation was found between FFR and percentage LAD diameter stenosis, and lesion length (all P values < .05), than between CFR and the same anatomic markers of stenosis severity (all P values = NS). The sensitivity, specificity, and positive and negative predictive values of CFR >2 to detect a nonsignificant lesion defined by normal FFR were 95%, 69%, 90%, and 82%, respectively. CONCLUSIONS: In patients with LAD stenosis of intermediate severity, discordant results between noninvasive CFR and FFR were not unusual, and the anatomic determinants of the stenosis were better correlated to FFR than to CFR. However, CFR, which is a global evaluation of the coronary tree, has very high sensitivity to detect a nonsignificant lesion, despite the high prevalence of vascular risk factors.

Non-invasive coronary flow reserve after successful primary angioplasty for acute anterior myocardial infarction is an independent predictor of left ventricular adverse remodelling.

AIMS: To assess the usefulness of non-invasive coronary flow reserve (CFR) to predict left ventricular adverse remodelling (LVR) after ST-elevation myocardial infarction (STEMI). METHODS AND RESULTS: Sixty-five consecutive patients (mean age 58 +/- 13 years, 24 women) with a first anterior STEMI, underwent prospectively CFR in the distal part of the left anterior descending artery (LAD), using intravenous adenosine infusion (0.14 mg/kg/min, within 2 min), and a standard echocardiography during the same exam, performed within 24 h after successful primary coronary angioplasty, and 6 months later, while the patients were in stable haemodynamic situation. CFR was defined as the peak hyperaemic LAD flow velocity divided by the baseline flow velocity. LV end-systolic volume (ESV) and end-diastolic volume (EDV), and LV ejection fraction (LVEF) were measured using the biplane Simpson's rule. LVR was defined as an absolute increase of ESV > or =15%. Compared with patients without LVR, patients with LVR (n = 18) had higher peak troponin T levels, wall motion score (WMS), a worse initial angiographic TIMI flow grade, and less improved electrocardiographic ST-segment resolution (all P < 0.05), and lower CFR (1.43 +/- 0.2 vs. 1.97 +/- 0.5, P < 0.01). At 6 months, patients with LVR had higher WMS, ESV, EDV, and lower LVEF compared with patients without LVR (all P < 0.01). Furthermore, acute CFR was significantly correlated to the 6-month LVEF and ESV, and to change of LVEF and ESV (all P < 0.01). In the multivariate analysis, acute CFR and initial angiographic TIMI flow grade were the independent predictors of LVR (all P < or = 0.01). Receiver-operating characteristic curve analysis demonstrated that a cut-off value of 1.7 for CFR yields a sensitivity of 100% and a specificity of 62% to predict LVR at follow-up (P < 0.001, area under the curve 0.82). CONCLUSION: Non-invasive CFR is an independent predictor of LVR after successful primary angioplasty of anterior STEMI.

Non-invasive coronary flow reserve after successful primary angioplasty for acute anterior myocardial infarction is an independent predictor of left ventricular recovery and in-hospital cardiac events.

BACKGROUND: The prediction of left ventricular (LV) recovery and adverse cardiac events after reperfused acute myocardial infarction (AMI) is challenging. The aim of this study was to assess the usefulness of noninvasive coronary flow reserve (CFR) to predict LV recovery and in-hospital adverse cardiac events after AMI by comparison with other available tools. METHODS: Fifty-five consecutive patients (mean age, 59 +/- 13 years; 33% women) with first reperfused ST-elevation anterior AMIs and sustained Thrombolysis in Myocardial Infarction (TIMI) grade 3 flow underwent prospectively, < 24 hours after successful primary coronary angioplasty, standard echocardiography and noninvasive CFR assessment in the distal part of the left anterior descending coronary artery, using intravenous adenosine infusion, while in a stable hemodynamic situation. CFR was defined as peak hyperemic left anterior descending coronary artery flow velocity divided by baseline flow velocity. LV ejection fraction (LVEF) was measured using the biplane Simpson's rule. A no-reflow pattern was defined as diastolic deceleration time of basal diastolic coronary flow velocity < 600 ms and/or systolic flow reversal and recovery of LV function as an absolute increase of LVEF >or= 10% at 3-month follow-up. Adverse events were defined as the composite of death, recurrent AMI, and acute heart failure. RESULTS: In the whole population, the mean LVEF was 46 +/- 5% at baseline and 55 +/- 9% at follow-up. Patients without LV recovery had more severely impaired CFR compared with those with LV recovery (2.1 +/- 0.55 vs 1.46 +/- 0.2, P < .001), as did patients with adverse events compared with those without events (P = .01). Furthermore, CFR was significantly correlated with 3-month LVEF and regional wall motion score (both P values < .01). On multivariate analysis, CFR was an independent predictor of global and regional LV function at follow-up (both P values

Prognostic value of transthoracic coronary flow reserve in medically treated patients with proximal left anterior descending artery stenosis of intermediate severity.

AIMS: Prognostic value of transthoracic coronary flow reserve (T-CFR) is not established in patients with left anterior descending artery (LAD) stenosis of intermediate severity. Objective is to determine the prognosis value of T-CFR>2 in medically treated patients with angiographically intermediate [50-70% QCA (quantitative coronary angiography)] proximal LAD stenosis. METHODS AND RESULTS: Among 110 consecutive patients with intermediate LAD stenosis who underwent prospectively T-CFR in the distal part of the LAD after intravenous administration of adenosine to assess the functional significance of the stenosis, 80 patients had T-CFR>2 and were treated medically without revascularization (Group 1). Among the 30 patients who had T-CFR<2, an additional dobutamine stress echocardiography (DSE) was performed: 15 had a negative DSE; were treated medically and served as a comparative group (Group 2), and 15 had a positive DSE; underwent LAD revascularization, and were excluded from further analysis. All patients completed follow-up (16+/-10 months). During the follow-up period (range 6-45 months), 76 patients (95%) remained free of death or LAD-related event in Group 1, vs. 12 patients (80%) in Group 2. By Kaplan-Meier method, at 30 months the per cent estimated survival free from death or target vessel-related events was 92+/-4% in Group 1 and 44+/-22% in Group 2 (P<0.01). By multivariate analysis, T-CFR remained the only independent predictor of death or LAD-related events. CONCLUSION: In patients with proximal LAD stenosis of intermediate severity and T-CFR>2, deferral of revascularization is associated with low event rate.

The coronary flow reserve is transiently impaired in tako-tsubo cardiomyopathy: a prospective study using serial Doppler transthoracic echocardiography.

The clinical features of tako-tsubo cardiomyopathy or transient left apical ballooning syndrome (LABS) have been clearly described, but the mechanisms are still unknown. Our objective was to prospectively assess coronary microcirculation at the acute phase of LABS and after functional recovery, using Doppler transthoracic echocardiography-coronary flow reserve (CFR). Twelve consecutive patients (11 women, mean age 68 +/- 10 years) satisfying the criteria for LABS underwent Doppler transthoracic echocardiography-CFR in the distal part of the left anterior descending coronary artery, using intravenous adenosine infusion (0.14 mg/kg/min over 2 minutes) at the acute phase and 25 +/- 3 days later. CFR was calculated as the ratio of hyperemic to basal mean diastolic flow velocity. Wall-motion score (WMS) was calculated using the 16-segment model during the same echocardiographic examination (normal WMS = 16). Doppler transthoracic echocardiography-CFR increased between the two examinations from 2.2 +/- 0.4 at the acute phase to 2.9 +/- 0.3 (P < .01), whereas WMS decreased (from 31 +/- 6 at the acute phase to 16.5 +/- 0.8, delta WMS = -14.6 +/- 6, P < .01). All patients exhibited an increase of CFR between the two tests (delta CFR = 0.73 +/- 0.39, range: 0.3-1.6). A significant correlation was observed between delta CFR and delta WMS (r = -0.89, P < .01). In conclusion, serial noninvasive CFR measurements performed in LABS suggested transient microcirculatory impairment during the acute phase of the syndrome. The wall-motion improvement parallel to the dynamic improvement of the microcirculation suggests a role of coronary microcirculatory damage in the pathogenesis of acute and transient wall-motion abnormalities in LABS.

Transthoracic coronary flow velocity reserve assessment: comparison between adenosine and dobutamine.

OBJECTIVE: We sought to compare coronary flow velocity reserve (CFVR) with adenosine and dobutamine in patients scheduled for noninvasive evaluation of coronary artery disease. BACKGROUND: Assessment of CFVR in the distal part of the left anterior descending coronary artery (LAD) by Doppler transthoracic echocardiography (TTE) is usually performed with adenosine in various settings. CFVR can also be determined during dobutamine stress echocardiography (DSE), but it has not been established whether TTE CFVR with dobutamine is equivalent to CFVR with adenosine. METHODS: In all, 47 consecutive stable patients in sinus rhythm (28 men, 64 +/- 12 years, left ventricular ejection fraction 55 +/- 5%) were prospectively studied. Coronary flow velocity was measured in the distal part of the LAD by TTE, at rest and during continuous infusion of 0.14 mg/kg/min of adenosine over 2 minutes, and during DSE performed immediately after the adenosine test, using a multifrequency transducer, on a modified parasternal view. CFVR with adenosine was calculated as hyperemic to basal peak flow velocity. CFVR with DSE was obtained by calculating peak diastolic flow velocity divided by baseline diastolic flow velocity. RESULTS: Adequate recording of CFVR with adenosine and dobutamine was possible in 43 (91%) and 41 (87%) patients, respectively. CFVR was 2.5 +/- 0.7 with adenosine compared with 2.4 +/- 0.7 with dobutamine (P = .7). A good linear correlation was observed between the two tests (r = 0.81, P < .0001). In patients with dobutamine-induced wall-motion abnormalities in the LAD territory (n = 8), CFVR was similar during dobutamine and adenosine infusion (1.6 +/- 0.3 vs 1.5 +/- 0.2, respectively, P = .7). Coronary angiography was available in 12 patients (LAD stenosis: 55 +/- 10% quantitative coronary angiography, with a range from 40%-75%). The correlation between CFVR values was also good in this subgroup of patients (r = 0.87, P < .0001). CONCLUSION: TTE CFVR with dobutamine is comparable to CFVR with adenosine in patients with a wide range of LAD diseases. Dobutamine could be a good alternative to adenosine for TTE CFVR assessment, particularly in patients with a contraindication to adenosine or scheduled for DSE.

Evaluation of left anterior descending coronary artery stenosis of intermediate severity using transthoracic coronary flow reserve and dobutamine stress echocardiography.

BACKGROUND: The physiologic significance of left anterior descending coronary artery (LAD) stenosis of intermediate angiographic severity is of clinical importance and difficult to assess. Assessment of coronary flow reserve (CFR) by Doppler transthoracic echocardiography (TTE) is a new tool and could allow rapid, noninvasive evaluation of stenosis severity in this setting. OBJECTIVE: We sought to evaluate the value of CFR measurement determined by TTE, compared with dobutamine stress echocardiography (DSE), in the setting of LAD stenosis of intermediate angiographic severity. METHODS: A total of 51 consecutive stable patients in sinus rhythm (33 men; age 65 +/- 12 years; left ventricular ejection fraction 59 +/- 7%) with no previous anterior myocardial infarction and with an angiographic proximal LAD stenosis of intermediate severity (56 +/- 8% quantitative coronary angioplasty) were prospectively studied. Coronary flow velocity was measured in the distal part of the LAD by TTE at rest and during continuous infusion of 0.14 mg/kg/min of adenosine over 2 minutes, using a multifrequency transducer, in the modified parasternal or 3-apical view. CFR was calculated as the ratio of hyperemic to basal mean (mean CFR) and peak (peak CFR) diastolic flow velocity. DSE was performed immediately after the adenosine test to assess ischemia in the LAD territory (percent maximum predicted heart rate = 94 +/- 8). RESULTS: Adequate recording of CFR was possible in 46 patients. Of the 35 patients with a CFR of 2 or more (peak CFR = 2.7 +/- 0.6), DSE was normal in 34. Of the 11 patients with a CFR less than 2 (peak CFR = 1.7 +/- 0.2), 7 had an abnormal response with DSE in the LAD territory. In this range of intermediate stenosis, there was a poor correlation between percent LAD diameter stenosis and CFR. For patients with positive DSE, CFR was 1.6 +/- 0.2 compared with 2.7 +/- 0.6 for patients with normal DSE (P < .05). The sensitivity, specificity, and the positive and negative predictive values of TTE CFR for detecting ischemia on DSE were 88%, 89%, 64%, and 97%, respectively, with an overall agreement of 89% between the two tests. CONCLUSION: Given its high negative predictive value, noninvasive CFR could be a useful aid in reaching clinical decisions promptly at the bedside in patients with moderately severe lesions of the proximal LAD.

Significance of systolic anterior motion of the mitral valve during dobutamine stress echocardiography.

Left ventricular outflow tract obstruction related to systolic anterior motion of the mitral valve (SAM) induced during dobutamine stress echocardiography (DSE) is not unusual but its significance is not established. A total of 100 consecutive patients (mean age 62 +/- 12 years; 67% male) without previous transmural myocardial infarction, valvular disease, or hypertrophic cardiomyopathy, undergoing DSE to assess the presence of myocardial ischemia, were prospectively evaluated. A SAM with DSE was searched and correlated with clinical and baseline echocardiographic findings. Patients who demonstrated SAM with DSE were selected for exercise echocardiographic Doppler study with bicycle, within 6 months of the DSE. The development of an intraventricular gradient with DSE or exercise was defined as a new gradient of > or =36 mm Hg. In all, 23 patients developed SAM during DSE with a mean gradient of 79 +/- 33 mm Hg (range: 39-144 mm Hg) and mitral regurgitation related to SAM. Compared with patients without SAM, patients who developed SAM with DSE were characterized at rest by a smaller mitroaortic angle and septoaortic angle, a higher posterior mitral leaflet length, and a smaller left ventricular cavity. Neither ischemic nor hypotensive response during DSE were correlated to SAM. In the group of patients with SAM, of the 9 patients who were referred for unexplained chest pain or dyspnea, 5 reproduced symptoms with DSE, compared with 2 of 17 patients in the group without SAM (P = .005). Despite these findings, only 3 of the 16 patients who underwent exercise echocardiography Doppler study developed SAM (two with symptoms), with a wide range of achieved heart rate, compared with DSE. Although patients with SAM with DSE exhibit predisposing echocardiographic findings, the clinical impact of this phenomenon is real in only a minority of patients, particularly those who experienced unexplained dyspnea or chest pain.