Takefumi Takahashi

Acute hyperglycaemia prevents the protective effect of pre-infarction angina on microvascular function after primary angioplasty for acute myocardial infarction

Background: Acute hyperglycaemia has been associated with impaired microvascular function after acute myocardial infarction (AMI), whereas pre-infarction angina (PIA) occurring shortly before the onset of AMI has been shown to reduce microvascular injury after reperfusion. Objective: To examine whether acute hyperglycaemia prevents the protective effect of PIA on microvascular function after AMI. Methods: We studied 205 patients with a first anterior wall AMI who underwent primary angioplasty within 12 hours of onset. Coronary flow velocity parameters were assessed immediately after reperfusion using a Doppler guidewire. Severe microvascular injury was defined as the presence of systolic flow reversal and diastolic deceleration time <600 ms. Echocardiographic wall motion was analysed before revascularisation and 4 weeks later. Results: Acute hyperglycaemia, defined as a blood glucose level of ⩾198 mg/dl on admission, was found in 67 (33%) patients. In patients without acute hyperglycaemia, PIA was associated with a lower incidence of systolic flow reversal, a longer diastolic deceleration time and a higher coronary flow reserve. However, in patients with acute hyperglycaemia there was no significant difference in these same parameters between patients with and without PIA. In the presence of acute hyperglycaemia PIA did not improve the change in wall motion score. In a multivariate model, the absence of PIA was an independent determinant of severe microvascular injury in patients without acute hyperglycaemia (odds ratio 6.28, p = 0.001), but not in patients with acute hyperglycaemia. Conclusion: The protective effect of PIA on microvascular function was attenuated in patients with acute hyperglycaemia, resulting in unfavourable functional recovery.

Intravascular ultrasound and quantitative coronary angiography

Coronary angiography is the gold standard in the assessment of coronary artery disease. However, two major limitations have been pointed out: observer variabilities of visual evaluation [1–3] and discrepancies between the contrast-filled lumen and the actual degree of underlying atherosclerosis [4–8]. These limitations have been thought to be due to the presence of diffuse disease without normal reference segments and compensatory remodeling of vessel walls [9,10]. Quantitative coronary angiography (QCA) has greatly reduced the first limitation. Several QCA systems can reproducibly define the site and degree of coronary stenosis [11]. However, the data from QCA analysis does not always provide accurate information on the degree of underlying atherosclerosis. On the other hand, intravascular ultrasound (IVUS) imaging can provide more reliable and detailed information of the vessel wall [12,13]. In addition, this method has offered significant advantage in various interventional techniques [14–16]. The aim of this article is to illustrate the basic technique and analysis of QCA and IVUS and to clarify the difference between the two methods.

Relation between the TIMI frame count and the degree of microvascular injury after primary coronary angioplasty in patients with acute anterior myocardial infarction

Objective: To investigate the relation between thrombolysis in myocardial infarction (TIMI) frame count (TFC) and coronary blood flow velocity (CBFV) parameters reflecting the degree of microvascular injury in patients with acute myocardial infarction. Results: TFC and CBFV were measured after primary coronary angioplasty in 103 consecutive patients with their first anterior wall acute myocardial infarction. TFC correlated inversely with the averaged peak velocity (r  =  −0.43, p < 0.0001). However, TFC did not correlate significantly with diastolic deceleration time and with the averaged systolic peak velocity (r  =  −0.16, p  =  0.22, and r  =  −0.23, p  =  0.16, respectively). The patients were divided into two groups according to presence (35 patients) or absence (68 patients) of systolic flow reversal. There was no significant difference in TFC between the two groups (29 (16) v 25 (13), p  =  0.20). Conclusions: These findings suggest that the TFC reflects epicardial CBFV. However, it is not accurate enough to assess the degree of microvascular injury after primary coronary angioplasty.

The potential benefits and risks of the use of dual antiplatelet therapy beyond 6 months following sirolimus-eluting stent implantation for low-risk patients

BACKGROUND The optimal duration of dual antiplatelet therapy (DAT) in patients undergoing intracoronary sirolimus-eluting stent implantation remains controversial. OBJECTIVE To evaluate the clinical effects of long duration DAT in patients undergoing intracoronary sirolimus-eluting stent implantation in daily practice. In addition, to attempt to identify the optimal duration of DAT after implantation of a sirolimus-eluting stent. METHODS We retrospectively report on 1293 consecutive patients who underwent successful intracoronary sirolimus-eluting stent implantation. We analyzed the cumulative incidence of stent thrombosis, non-fatal myocardial infarction (MI), death from cardiac causes, and the cumulative incidence of bleeding complications. RESULTS We compared the study end point in patients who received DAT for <6 months (n=1136) with that for patients who received DAT for >6 months (n=157). The median follow-up period was 1260 ± 462 days. Major bleeding occurred in 35 patients and intracranial hemorrhage in 8. In patients on DAT for >6 months, the incidence of any bleedings, major bleedings, and intracranial hemorrhage was significantly increased. On the other hand, there was no significant difference between the two groups in the risk of the primary end points (stent thrombosis, non-fatal MI, death from cardiac causes, death or MI). CONCLUSIONS Prolonged DAT for more than 6 months was not significantly more beneficial than aspirin monotherapy in reducing the risk of the occurrence of acute MI, stent thrombosis, and death, although it was associated with an increase in bleeding complications for low-risk patients.

Waist circumference reduction is more strongly correlated with the improvement in endothelial function after acute coronary syndrome than body mass index reduction

BACKGROUND Endothelial function predicts recurrence of adverse cardiac events in patients with acute coronary syndromes (ACS). Moreover, the recovery of endothelial function correlates with cardiac event-free survival. OBJECTIVES The aim of this study was to determine which clinical factors correlate with the improvement in endothelial function after ACS. METHODS Vascular endothelial function was assessed in 98 patients with ACS by flow-mediated dilation (FMD) of the brachial artery using high-resolution ultrasound at 2 weeks and 6 months after ACS. We measured several risk parameters including plasma markers of glucose homeostasis, lipids, and blood pressure at baseline and at 6 months after ACS. Body mass index (BMI) and waist circumference (WC) were also measured as anthropometric assessments. RESULTS At baseline, FMD was significantly correlated with BMI, WC, high-density lipoprotein cholesterol, the homeostasis model assessment of insulin resistance, and brachial artery diameter (r=-0.32, p=0.001; r=-0.44, p<0.0001; r=0.34, p=0.0006; r=-0.21, p=0.04; r=-0.47, p<0.0001, respectively). In a stepwise multivariate regression analysis at baseline, larger WC and brachial artery diameter were independently correlated with lower brachial artery FMD (R(2)=0.319, p<0.0001). At 6 months, the change in FMD was significantly correlated with the change in WC and BMI (r=-0.59, p<0.0001; r=-0.33, p=0.001, respectively). In a stepwise multivariate regression analysis, WC reduction was independently correlated with improved FMD (R(2)=0.349, p<0.0001). CONCLUSIONS WC reduction is more strongly correlated with the improvement of endothelial function after ACS than BMI reduction.

The impact of gender difference on the effects of preinfarction angina on microvascular damage with reperfused myocardial infarction.

Few studies have addressed gender differences in evoking preconditioning. In an experimental study, it was reported that the preconditioning effect disappeared after gonadectomy.

Ultrasonic Strain Versus Coronary Flow Velocity Pattern for Predicting Regional Wall Motion Recovery After Primary Coronary Intervention for Acute Myocardial Infarction

BACKGROUND Strain Doppler echocardiography can detect regional myocardial dysfunction after acute myocardial infarction (AMI). The aim of this study was to assess the utility of strain in predicting regional wall motion recovery after AMI compared with the coronary flow velocity pattern. METHODS Thirty-three patients with anterior AMIs undergoing successful coronary intervention were included. Longitudinal myocardial strain and coronary flow velocity were measured <24 hours after coronary intervention. Regional wall motion was analyzed by the anterior wall motion score index (A-WMSI). RESULTS End-systolic strain (r = 0.72, P < .0001), peak strain (r = 0.58, P < .005), and corrected time to peak strain (the time delay from end-systolic to peak strain divided by the RR interval) (r = 0.80, P < .0001) showed good correlations with A-WMSI at 4 weeks. Similarly, diastolic deceleration time was significantly correlated with A-WMSI at 4 weeks (r = 0.69, P < .0001). The diagnostic value in predicting wall motion recovery was compared using a receiver operating characteristic curve. The area under the curve of corrected time to peak strain tended to be larger than that of diastolic deceleration time (0.94 +/- 0.04 vs 0.86 +/- 0.06). CONCLUSION Strain can predict left ventricular wall motion recovery in patients with AMIs after coronary intervention comparable with predictions using the coronary flow velocity pattern.

Formation of a coronary artery aneurysm after inflation of a PercuSurge GuardWire distal protection balloon

Formation of aneurysms in the coronary arteries with the use of the PercuSurge distal protection system has not been reported. We describe a 54‐year‐old man with acute myocardial infarction who was treated with the PercuSurge system. Angiography performed 2 weeks later revealed an aneurysm in the area of inflation of the distal protection balloon. Catheter Cardiovasc Interv 2005;64:82–84.

Comparison of results of rotational atherectomy for diffuse coronary artery disease in diabetics versus nondiabetics.

patients undergoing stress testing have VPCs at rest and/or during exercise. In our own database, the incidence of VPCs at rest and/or during exercise was only 6% in 13,000 records reviewed. Another confounding element was that data came from a major cardiac center where the referral pattern may influence the prevalence of disease. This same bias exists in any study where angiograms are compared with exercise tests.

Mechanisms of lumen narrowing of saphenous vein bypass grafts 12 months after implantation: an intravascular ultrasound study

BACKGROUND Previous long-term (>1 year) studies have suggested that saphenous vein bypass grafts (SVGs) undergo vascular remodeling similar to native coronary arteries. However, early morphologic stages of SVG remodeling have not been characterized in vivo. METHODS Thirty SVGs were studied 12 months after implantation using an intravascular ultrasound automated pullback system. Intravascular ultrasound images were analyzed between 10 and 60 mm from the tip of the guide. Lumen area (LA), intima area (IA), and vessel area (VA, defined as the area within the outer border of a hypoechoic intimal layer) were computed at 3 cross sections: the minimum LA (MLA) site and the proximal and distal reference sites. Area changes (Delta) were calculated as the MLA site minus the average of the reference sites. RESULTS In this cohort, 70% of the MLA sites had a smaller VA than the average references. On average, MLA sites had significantly smaller VA (9.7 +/- 2.9 vs 10.7 +/- 3.2 mm2, P < .01) and larger IA (2.5 +/- 2.1 vs 1.2 +/- 1.3 mm2, P < .01) than at the reference sites. The relative contribution of DeltaVA (-1.0 +/- 1.4 mm2) and DeltaIA (1.3 +/- 1.3 mm2) to lumen compromise (-2.3 +/- 1.4 mm2) were 43% and 57%, respectively. On the other hand, simple linear regression analysis revealed a significant positive correlation between DeltaIA and DeltaVA (y = -1.7 + 0.52x, r = 0.50, P < .01). CONCLUSIONS Within the first year, the mechanism of lumen compromise in SVG is a combination of negative remodeling and intimal hyperplasia. Positive remodeling is seen in a minority of cases. However, the direction and extent of remodeling correlated with change in intimal thickness.