Assessment of left anterior descending artery stenosis of intermediate severity by fractional flow reserve, instantaneous wave-free ratio, and non-invasive coronary flow reserve

To test the usefulness of non-invasive coronary flow reserve (CFR) by transthoracic Doppler echocardiography by comparison to invasive fractional flow reserve (FFR) and instantaneous wave-free ratio (IFR), a new vasodilator-free index of coronary stenosis severity, in patients with left anterior descending artery (LAD) stenosis of intermediate severity (IS) and stable coronary artery disease. 94 consecutive patients (mean age 68 ± 10 years) with angiographic LAD stenosis of IS (50-70 % diameter stenosis), were prospectively studied. IFR was calculated as a trans-lesion pressure ratio during the wave-free period in diastole; FFR as distal pressure divided by mean aortic pressure during maximal hyperemia (using 180 μg intracoronary adenosine); and CFR as hyperemic peak LAD flow velocity divided by baseline flow velocity using intravenous adenosine (140 μg/kg/min over 2 min). The mean values of IFR, FFR, and CFR were 0.88 ± 0.07, 0.81 ± 0.09, and 2.4 ± 0.6 respectively. A significant correlation was found between CFR and FFR (r = 0. 68), FFR and IFR (r = 0.6), and between CFR and IFR (r = 0.5) (all, p < 0.01). Using a ROC curve analysis, the best cut-off to detect a significant lesion based on FFR assessment (FFR ≤ 0.8, n = 31) was IFR ≤ 0.88 with a sensitivity (Se) of 74 %, specificity (Sp) of 73 %, AUC 0.81 ± 0.04, accuracy 72 %; and CFR ≤ 2 with a Se = 77 %, Sp = 89 %, AUC 0.88 ± 0.04, accuracy 85 % (all, p < 0.001). In stable patients with LAD stenosis of IS, non-invasive CFR is a useful tool to detect a significant lesion based on FFR. Furthermore, there was a better correlation between CFR and FFR than between CFR and IFR, and a trend to a better diagnostic performance for CFR versus IFR.

[Voluminous thrombus straddling the patent foramen oval in the setting of massive pulmonary embolism, treated successfully by surgery]

Paradoxical embolism is rarely demonstrated, often suggested, and the diagnosis has been largely presumptive in most cases. The patent foramen ovale (PFO) is an important predisposing anatomic factor for such a complication. We describe a case where a voluminous thrombus straddling the PFO was diagnosed by echocardiography including the 3D modality, in the setting of acute massive pulmonary embolism. The treatment is not codified in this setting, and the thrombus was successfully removed by surgery, associated with PFO closure, and anticoagulation.

Systolic anterior motion of the mitral valve in tako-tsubo cardiomyopathy: Still a matter of debate?

We present a case which developed a typical tako-tsubo-like cardiomyopathy (TTC) during dobutamine stress echocardiography (DSE). Its originality is related to several findings, which have never been described simultaneously in the same patient. This 63-year-old woman with normal coronary angiography and no evidence of coronary vasospasm had a biphasic response to DSE, a finding which usually occurs in coronary artery disease. Moreover, the symmetric extensive wall motion abnormalities (WMA) occurred simultaneously with the development of a systolic anterior motion of the mitral valve (SAM) and left ventricular obstruction, and was clinically asymptomatic. Although in TTC the stunning usually occurs for several days, WMA and SAM resolved within few minutes after cessation of dobutamine and administration of a beta-blocker. And finally, exercise echo performed at the same target heart rate few days later did not induce neither a SAM nor WMA, which suggests that left ventricular obstruction could have played a role in the pathogenesis of this case by supply-demand mismatch. Concomitant coronary microvascular dysfunction was also demonstrated by a reduction of the non-invasive coronary flow reserve in the distal part of the left anterior descending artery.

[Incidence, associated factors, and follow-up of hospital heart failure complicating acute anterior myocardial infarction successfully treated by primary angioplasty]

Heart failure (HF) complicating acute myocardial infarction (AMI) is of poor prognosis and is often associated with patient's characteristics and success of reperfusion strategies. However, few data is available regarding the high-risk subgroup of patients with anterior AMI treated successfully by primary angioplasty. The aim of the study was to assess the incidence, associated factors, and the future of HF occurring during hospitalisation, in the setting of anterior AMI treated successfully by primary angioplasty.

METHODS

Eighty-five consecutive patients with anterior AMI treated successfully by primary angioplasty (final angiographic TIMI flow grade=3, without residual stenosis) were included. Clinical, biochemical, angiographic, and echocardiographic data were prospectively collected and compared between patients with (Killip 2 and 3) and without HF during hospitalisation.

RESULTS

Fifteen patients had HF (18%) during hospitalisation and 70 did not. By comparison to patients without HF, patients with HF were more frequently diabetics, had troponin peak and CPK, leucocytes count, and fasting glucose higher, LVEF and wall motion score index in the left anterior descending territory (WMSi-lad) poorer, and a lower non-invasive coronary flow reserve (CFR) in the LAD 24hours after angioplasty (all, P<0.05). In multivariate analysis, fasting glucose, leucocytes count after angioplasty, CFR and WMSi-lad were independently associated with HF, even after adjusting with angiographic variables (all, P<0.05). At 6months, patients with HF had less recovery of LV function and higher frequency of adverse LV remodelling (58% versus 20%, P<0.01) by comparison to patients without HF.

CONCLUSION

In conclusion, HF is not uncommon even after successful primary angioplasty for anterior AMI (nearly one patient out of 5), is associated with hyperglycaemia and inflammation, a poor microvascular reperfusion, and left ventricular systolic function, and is more frequently complicated by adverse LV remodelling and lack of LV recovery.

[Non-invasive coronary flow reserve is an independent predictor of exercise capacity after acute anterior myocardial infarction]

BACKGROUND

After acute myocardial infarction (MI) coronary microvascular impairment and reduced exercise capacity are both determinant of prognosis.

OBJECTIVE

We tested whether non-invasive coronary flow reserve (CFR) performed after MI predicts post-MI exercise capacity (EC).

METHODS

Fifty consecutive patients (pts) (mean age 56.5±11years, 30% women) with a first reperfused ST-elevation anterior MI, and sustained TIMI 3 flow after mechanical reperfusion, underwent prospectively non-invasive CFR in the distal part of the left anterior descending artery (LAD), using intravenous adenosine infusion (0.14mg/kg per minute, within 2min), within 24h after successful primary coronary angioplasty (CFR 1), and 4±1.6months later after a period of convalescence and a cardiac rehabilitation program (CFR 2). CFR was defined as peak hyperaemic LAD flow velocity divided by baseline flow velocity. All pts also underwent semi-supine exercise stress echocardiography (ESE) the same day of CFR 2. ESE was performed at an initial workload of 25-30watts with a 20watts increase at 2-minute intervals. Beta-blockers were withheld 24h before ESE.

RESULTS

The mean CFR 2 increased significantly when compared to CFR 1 (2.9±0.65 versus 1.9±0.4, P<0.01). During ESE, percentage of maximal predict heart rate achieved was 82±12%, maximal workload 95±30watts, exercise duration 486±155s, the ratio of double product 3.1±0.8, and EC 5.8±1.1 metabolic equivalents. No ischemia was induced during ESE in all pts, and the degree of mitral regurgitation did not differ significantly between rest and exercise. CFR 2 was significantly correlated to all indices related to EC (all, P<0.01), whereas CFR 1 was correlated to LV systolic function at follow-up (P<0.05) but not to EC. In multivariate analysis including age, sex, and body mass index, CFR 2 remained an independent predictor of EC (P<0.01).

CONCLUSION

Contrarily to acute CFR, CFR at follow-up is an independent predictor of EC after reperfused anterior MI. This suggests that the improvement of the coronary microcirculation is closely linked to the physical aptitude after MI.

[Assessment of left ventricular twist mechanics by two-dimensional strain in severe aortic stenosis with preserved ejection fraction]

Left ventricular (LV) twist is increased in aortic stenosis (AS) and the hypothesis of a compensatory mechanism is suggested but not established. Our aim was to assess LV twist mechanics in severe AS (<1cm(2) or 0.6cm(2)/m(2)) with preserved LV ejection fraction (LVEF>50%), and to analyze its relationship with LV systolic longitudinal function, early impaired in this setting, LV diastolic function, and symptomatic status.

METHODS

Forty-five consecutive patients with severe AS and preserved LVEF (mean age 73±11 years, 47% female, LVEF 68±11%, 67% symptomatic) underwent a transthoracic echocardiography including a bidimensional strain analysis by speckle tracking method, and were compared to a control group matched for age and sex (n=15). Global longitudinal strain (GLS) was measured using the four, two, and three apical views, and LV twist mechanics from the basal and apical short axis views. LV twist was defined as the net difference between apical and basal rotation, and LV twisting and untwisting rate (in°/s) were derived from twist curves.

RESULTS

Peak apical rotation, LV twist (25±8° vs 20±6), as well as peak systolic and diastolic apical rotation rate, and peak LV twisting rate were significantly higher in patients with AS when compared to controls (all, P<0.05), whereas, the other parameters of LV twist mechanics including basal rotation, were not significantly different between groups. By contrast, the GLS was significantly lower in patients with AS when compared to controls (-17.9±4 vs -20.5±2%, P<0.01). In addition, the GLS was significantly correlated to LV torsion (r=-0.42, P<0.01). Moreover, LV twist progressively impaired with the worsening of diastolic dysfunction and with symptoms onset.

CONCLUSION

LV twist is increased in severe AS with preserved LVEF, compensating the impairment of systolic longitudinal function. However, above a certain threshold LV twist deteriorates, attesting the failure of the compensatory mechanisms, leading to advanced diastolic dysfunction and symptom onset.

[Influence of leukocytes on coronary flow reserve, left ventricular systolic function, and in-hospital events, in patients with acute anterior myocardial infarction treated by primary angioplasty]

OBJECTIVE

To assess the relationship between leukocyte count, non invasive coronary flow reserve (CFR), left ventricular systolic function, and in-hospital adverse events in acute anterior myocardial infarction (AMI) treated by primary angioplasty.

METHODS

Leukocyte count at admission and within 24h after angioplasty, and differential count at admission were obtained in 72 consecutive patients with a first AMI (mean age 56±12 years) successfully treated by primary angioplasty. Transthoracic Doppler echocardiography was performed within 24h after angioplasty and 3 months later to assess the CFR (using intravenous adenosine), in the left anterior descending artery (LAD), left ventricular ejection fraction (LVEF) and the wall motion score index using the nine segments assigned to the LAD territory (WMSi-lad). In hospital events were defined as death, heart failure (Killip≥2) and reinfarction.

RESULTS

Leukocyte count was higher before and after angioplasty in patients with impaired acute CFR (<1.7), when compared to patients without such impairment (P≤0.01), and a significant correlation was found between CFR and leukocyte, neutrophil and monocyte count (P<0.05). Leukocyte (before and after angioplasty), and neutrophil count, were lower in patients with recovery of global and regional LV function (P<0.05). A significant correlation was found between leukocyte count before and after angioplasty, and, initial and follow-up LVEF, and WMSi-lad (all, P≤0.01). Leukocyte (before and after angioplasty) and monocyte count were higher in patients with in-hospital events (n=14), by comparison to patients without events (all, P<0.01). In multivariate analysis, leukocyte count after angioplasty was an independent predictor of CFR, and in-hospital events, and neutrophil count of WMSi-lad at follow-up (all, P<0.05).

CONCLUSION

In the first AMI treated successfully by primary angioplasty, leukocyte count is inversely correlated to CFR, and global and regional LV systolic function at follow-up. These links are higher after than before reperfusion. And, leukocyte count after angioplasty is an independent predictor of in-hospital adverse events.

[Pre-hospitalization treatment with Abciximab in the preparation of patients for primary angioplasty in the acute phase of myocardial infarct. Immediate and long-term (one month) results]

Percutaneous transluminal coronary angioplasty (PTCA) is an alternative to fibrinolysis in the treatment of acute myocardial infarction (AMI). However, after balloon PTCA, the rate of early re-occlusion, of re-infarctus and of restenosis remains high. Stent implantation with antiplatelet drug regimen (aspirin, ticlid) limits these risks. Abciximab (new GPIIb/IIIa receptors inhibitor) reduces PTCA complications rate in the acute coronary syndromes. Intravenous administration of abciximab can restore a normal flow in the infarcted related coronary artery (IRA) after few minutes. A monocentric, non randomized, prospective pilot study was iniated to assess the feasibility of pre-hospital treatment with abciximab in preparation to primary PTCA stenting in AMI (primary endpoint) and to appreciate potential benefits in initial IRA patency as well as prevention of PTCA thrombotic complications (secondary endpoint). Between April 1997 and January 1998, 38 AMI were treated with abciximab in pre-hospital phase (group A). Mobil Intensive Care Unit (MICU) team implemented the treatment and guaranteed immediate transport to the cathlab (abciximab bolus-coronary angiography time = 37 +/- 17 min). Immediate results were compared to those of 198 paired patients who were treated for AMI during the same period (Group T). Initial IRA flow TIMI grade 3 was significantly higher in group A, 24%, than in group T, 9% (p < 0.017). The rates of per-procedural complications (no flow, distal embolism), of local complications, of transfusions were not significantly different. During 1 month follow-up, there was no significant difference between group A and group T concerning death, re-MI, stent thrombosis and new revascularization. To conclude, the pre-hospital treatment with abciximab in AMI is feasible by MICU medical team without any delay of the cathlab admission. It is associated with no increased hemorrhagic complications rate. The abciximab pre-hospital treatment improves the initial IRA patency. These encouraging preliminary results expect to be confirmed by larger, multicentric, randomized and prospective studies.