Improvement of cardiac function by increasing stimulus strength during left ventricular pacing in cardiac resynchronization therapy.

Cardiac resynchronization therapy (CRT) is an established therapy in patients with severe heart failure due to left ventricular (LV) dyssynchrony. Increasing stimulus strength (SS) of LV pacing could capture an enlarged myocardial area and provide rapid electrical conduction. The aim of the present study was to investigate whether increasing SS of LV pacing improves LV mechanical dyssynchrony and cardiac function in patients treated with CRT.We enrolled 26 patients with CRT and changed the SS of LV pacing: 2.5 V (standard SS) and 5 V (high SS). Electrocardiography and echocardiography were performed to assess QRS duration, LV mechanical dyssynchrony, and cardiac function under each condition.The QRS duration (138.6 ± 21.4 ms versus 126.8 ± 23.1 ms, P < 0.001), septal-posterior wall motion delay (126.5 ± 42.7 ms versus 111.4 ± 55.3 ms, P = 0.012), standard deviation of time from QRS (69.6 ± 21.8 ms versus 55.6 ± 19.4 ms, P < 0.001), LV ejection fraction (29.4 ± 10.6% versus 33.4 ± 11.6%, P = 0.005), and LV stroke volume (50.7 ± 15.5 mL versus 63.8 ± 18.3 mL, P < 0.001) improved significantly in high SS compared with standard SS.Increasing SS of LV pacing in CRT improves LV mechanical dyssynchrony and cardiac function. The capture of an enlarged myocardial area by increasing SS of LV pacing might offer an acute hemodynamic benefit to patients treated with CRT.

Altered coronary flow velocity reserve and left ventricular wall motion dynamics: a phenomenon in hypertensive patients with ECG strain.

BACKGROUND: The inner-half layer of the left ventricular (LV) wall is primarily affected by ischemia and increased LV afterload. We hypothesized that LV wall thickening of inner-half layer and coronary microvascular function are impaired in hypertensive patients, especially in those with electrocardiographic (ECG) strain, which is a marker of LV hypertrophy and adverse prognosis. Therefore, the aim of this study is to investigate the association of the ratio of inner- to outer-half layer of the LV myocardial deformation and coronary microvascular function with ECG strain in hypertensive patients. METHODS: We studied 98 hypertensive patients and 13 controls. Hypertensive patients were divided into 2 groups, with (S+) and without (S-) ECG strain. Coronary flow velocity reserve (CFVR) of the left anterior descending artery was evaluated using transthoracic echocardiography. Circumferential and radial strains of the LV wall were analyzed by two-dimensional echocardiographic speckle tracking method, and the inner- to outer-half layer ratio (in/out ratio) was assessed. RESULTS: Coronary flow velocity reserve of S+ (2.06 ± 0.65) was significantly smaller than those in S- and controls (3.03 ± 0.65 and 3.38 ± 0.51, respectively). In/out ratio in both circumferential and radial strains were decreased as well as in S+ patients. Furthermore, in/out ratio was directly proportional to CFVR. CONCLUSIONS: Hypertensive patients with ECG strain possessed severely impaired CFVR and inner-half myocardial deformation. Moreover, the more severe the LV hypertrophy progresses, the greater is the impairment of coronary microvascular and LV inner-half myocardial deformation. Thus, CFVR and in/out ratio are useful quantitative markers that can render sensitive assessment of physiological changes in hypertensive heart disease.

Clinical significance of low signal intensity area surrounding stent struts identified by optical coherence tomography.

Previous intravascular ultrasound studies have shown that echolucent neointimal hyperplasia occasionally appears after bare-metal stent (BMS) or sirolimus-eluting stent (SES) implantation. Optical coherence tomography (OCT) studies have also demonstrated that paclitaxel-eluting stent (PES) restenosis exhibited similar images showing low signal intensity areas (LSIA) surrounding stent struts and three-layer appearance (TLA). The aim of the present study was to investigate the clinical significance of LSIA on OCT images in various types of stents. Fifty nine consecutive patients who underwent scheduled follow-up coronary angiography and OCT were enrolled. There was no significant difference in the prevalence of LSIA among the 3 stent groups (BMS 30%, SES 19%, PES 28%, P = 0.70). LSIA thickness was larger in the PES group than in the other stent groups (BMS 0.51 ± 0.21 mm, SES 0.35 ± 0.06 mm, PES 0.87 ± 0.19 mm, P < 0.01). The ratio of LSIA thickness to the neointimal thickness was also larger in PES compared with other stents (BMS 53 ± 9 %, SES 57 ± 8 %, PES 77 ± 5 %, P < 0.01). Also, LSIA thickness in patients with in-stent restenosis (ISR) was significantly larger than in those without ISR (0.37 ± 0.37 mm versus 0.12 ± 0.26 mm, P = 0.048). Our results suggest that LSIA might be involved in excessive neointimal formation, and that the healing response after PES implantation might be different from BMS or SES.

Quantification of absolute coronary flow reserve and relative fractional flow reserve in a swine animal model using angiographic image data.

Coronary flow reserve (CFR) and fractional flow reserve (FFR) are important physiological indexes for coronary disease. The purpose of this study was to validate the CFR and FFR measurement techniques using only angiographic image data. Fifteen swine were instrumented with an ultrasound flow probe on the left anterior descending artery (LAD). Microspheres were gradually injected into the LAD to create microvascular disruption. An occluder was used to produce stenosis. Contrast material injections were made into the left coronary artery during image acquisition. Volumetric blood flow from the flow probe (Q(q)) was continuously recorded. Angiography-based blood flow (Q(a)) was calculated by using a time-density curve based on the first-pass analysis technique. Flow probe-based CFR (CFR(q)) and angiography-based CFR (CFR(a)) were calculated as the ratio of hyperemic to baseline flow using Q(q) and Q(a), respectively. Relative angiographic FFR (relative FFR(a)) was calculated as the ratio of the normalized Q(a) in LAD to the left circumflex artery (LC(X)) during hyperemia. Flow probe-based FFR (FFR(q)) was measured from the ratio of hyperemic flow with and without disease. CFR(a) showed a strong correlation with the gold standard CFR(q) (CFR(a) = 0.91 CFR(q) + 0.30; r = 0.90; P < 0.0001). Relative FFR(a) correlated linearly with FFR(q) (relative FFR(a) = 0.86 FFR(q) + 0.05; r = 0.90; P < 0.0001). The quantification of CFR and relative FFR(a) using angiographic image data was validated in a swine model. This angiographic technique can potentially be used for coronary physiological assessment during routine cardiac catheterization.

Effect of strut thickness on neointimal atherosclerotic change over an extended follow-up period (≥ 4 years) after bare-metal stent implantation: intracoronary optical coherence tomography examination.

BACKGROUND: Neointima inside the bare-metal stents (BMSs) can transform into atherosclerotic tissue during an extended follow-up because of a persistent inflammatory reaction to the metal. We sought to investigate whether strut thickness may impact on the atherosclerotic change in neointima 4 years or more after BMS implantation using optical coherence tomography. METHODS: Forty-six stented lesions of 41 patients with BMS ≥ 4 years after implantation who underwent optical coherence tomography were enrolled in the study. The strut was defined as thin when less than 100 µm and thick when ≥ 100 µm. According to these criteria, stents were divided into 2 groups (thin strut n = 19, thick strut n = 27). Neointimal tissue was categorized into normal neointima, characterized by a signal-rich band without signal attenuation, or lipid-laden intima, with marked signal attenuation and a diffuse border. Intimal disruption, thrombus, and neovascularization were also evaluated. RESULTS: The mean period after implantation was 98.2 ± 25.8 months in the thin-strut group and 91.1 ± 22.8 months in the thick-strut group (P = .330). Lipid-laden intima (70% vs 32%, P = .016), thin-cap fibroatheroma-like intima (59% vs 16%, P = .0056), and intimal disruption (48% vs 16%, P = .031) were observed more frequently in the thick-strut group than in the thin-strut group, but no significant difference was observed in the frequency of thrombus. Although peristrut neovascularization was a common finding in both groups (thick vs thin 81% vs 79%, P = 1.000), the frequency of intraintima neovascularization tended to be higher in the thick-strut group (67% vs 42%, P = .135). CONCLUSIONS: A thinner strut thickness may have favorable effects on neointimal atherosclerotic changes after BMS implantation.

Comparison of contrast media and low-molecular-weight dextran for frequency-domain optical coherence tomography.

BACKGROUND: Although an intracoronary frequency-domain optical coherence tomography (FD-OCT) system overcomes several limitations of the time-domain OCT (TD-OCT) system, the former requires injection of contrast media for image acquisition. The increased total amount of contrast media for FD-OCT image acquisition may lead to the impairment of renal function. The safety and usefulness of the non-occlusion method with low-molecular-weight dextran L (LMD-L) via a guiding catheter for TD-OCT image acquisition have been reported previously. The aim of the present study was to compare the image quality and quantitative measurements between contrast media and LMD-L for FD-OCT image acquisition in coronary stented lesions. METHODS AND RESULTS: Twenty-two patients with 25 coronary stented lesions were enrolled in this study. FD-OCT was performed with the continuous-flushing method via a guiding catheter. Both contrast media and LMD-L were infused at a rate of 4 ml/s by an autoinjector. With regard to image quality, the prevalence of clear image segments was comparable between contrast media and LMD-L (97.9% vs. 96.5%, P=0.90). Furthermore, excellent correlations were observed between both flushing solutions in terms of minimum lumen area, mean lumen area, and mean stent area. The total volumes of contrast media and of LMD-L needed for OCT image acquisition were similar. CONCLUSIONS: FD-OCT image acquisition with LMD-L has the potential to reduce the total amount of contrast media without loss of image quality.

Prevalence and clinical significance of papillary muscle infarction detected by late gadolinium-enhanced magnetic resonance imaging in patients with ST-segment elevation myocardial infarction.

BACKGROUND: The frequency of papillary muscle infarction (PapMI) without rupture has not been fully investigated in vivo. Furthermore, the relationship between papillary muscle dysfunction and mitral regurgitation (MR) has been controversial in patients with ST-segment elevation myocardial infarction. Therefore, the aim of this study was to assess the frequency and clinical characteristics of PapMI without rupture using late gadolinium-enhanced magnetic resonance imaging (MRI) in patients with ST-segment elevation myocardial infarction. METHODS AND RESULTS: One hundred eighteen ST-segment elevation myocardial infarction patients with primary percutaneous coronary intervention underwent cardiac MRI twice 9±4 days and 8±1 months (n=104) after myocardial infarction. MR was categorized by echocardiography. Of these patients, 40% were found to have late gadolinium enhancement of papillary muscle, in which the posterior papillary muscle was involved more frequently than the anterior papillary muscle (77% versus 26%; P<0.001). PapMI was encountered more frequently in patients with left circumflex and right coronary artery lesions compared with left anterior descending artery lesion (78%, 48%, and 13%; P<0.001). By multiple logistic regression analysis, only coaptation height was identified as an independent predictor of the presence of MR. The second cardiac magnetic resonance imaging showed that the infarct size had a positive correlation with left ventricular end-diastolic volume (r=0.41, P<0.001) and that PapMI was not associated with left ventricular remodeling (P=0.31). Deterioration of MR was not observed in patients with PapMI. CONCLUSIONS: PapMI is more frequent than previously thought yet appears to have significant clinical latency. The size of the myocardial infarction, but not the presence of PapMI, seems to affect left ventricular remodeling, and PapMI is not obligatorily associated with MR.

Assessment of coronary microcirculation in a swine animal model.

Coronary microvascular dysfunction has important prognostic implications. Several hemodynamic indexes, such as coronary flow reserve (CFR), microvascular resistance, and zero-flow pressure (P(zf)), were used to establish the most reliable index to assess coronary microcirculation. Fifteen swine were instrumented with a flow probe, and a pressure wire was advanced into the distal left anterior descending artery. Adenosine was used to produce maximum hyperemia. Microspheres were used to create microvascular dysfunction. An occluder was used to produce stenosis. Blood flow from the probe (Q(p)), aortic pressure, distal coronary pressure, and right atrium pressure were recorded. Angiographic flow (Q(a)) was calculated using a time-density curve. Flow probe-based CFR and angiographic CFR were calculated using Q(p) and Q(a), respectively. Flow probe-based (NMR(qh)) and angiographic normalized microvascular resistance (NMR(ah)) were determined using Q(p) and Q(a), respectively, during hyperemia. P(zf) was calculated using Q(p) and distal coronary pressure. Two series of receiver operating characteristic curves were generated: normal epicardial artery model (N model) and stenosis model (S model). The areas under the receiver operating characteristic curves for flow probe-based CFR, angiographic CFR, NMR(qh), NMR(ah), and P(zf) were 0.855, 0.836, 0.976, 0.956, and 0.855 in N model and 0.737, 0.700, 0.935, 0.889, and 0.698 in S model. Both NMR(qh) and NMR(ah) were significantly more reliable than CFR and P(zf) in detecting the microvascular deterioration. Compared with CFR and P(zf), NMR provided a more accurate assessment of microcirculation. This improved accuracy was more prevalent when stenosis existed. Moreover, NMR(ah) is potentially a less invasive method for assessing coronary microcirculation.

Quantification of coronary microvascular resistance using angiographic images for volumetric blood flow measurement: in vivo validation.

Structural coronary microcirculation abnormalities are important prognostic determinants in clinical settings. However, an assessment of microvascular resistance (MR) requires a velocity wire. A first-pass distribution analysis technique to measure volumetric blood flow has been previously validated. The aim of this study was the in vivo validation of the MR measurement technique using first-pass distribution analysis. Twelve anesthetized swine were instrumented with a transit-time ultrasound flow probe on the proximal segment of the left anterior descending coronary artery (LAD). Microspheres were injected into the LAD to create a model of microvascular dysfunction. Adenosine (400 µg·kg(-1)·min(-1)) was used to produce maximum hyperemia. A region of interest in the LAD arterial bed was drawn to generate time-density curves using angiographic images. Volumetric blood flow measurements (Q(a)) were made using a time-density curve and the assumption that blood was momentarily replaced with contrast agent during the injection. Blood flow from the flow probe (Q(p)), coronary pressure (P(a)), and right atrium pressure (P(v)) were continuously recorded. Flow probe-based normalized MR (NMR(p)) and angiography-based normalized MR (NMR(a)) were calculated using Q(p) and Q(a), respectively. In 258 measurements, Q(a) showed a strong correlation with the gold standard Q(p) (Q(a) = 0.90 Q(p) + 6.6 ml/min, r(2) = 0.91, P < 0.0001). NMR(a) correlated linearly with NMR(p) (NMR(a) = 0.90 NMR(p) + 0.02 mmHg·ml(-1)·min(-1), r(2) = 0.91, P < 0.0001). Additionally, the Bland-Altman analysis showed a close agreement between NMR(a) and NMR(p). In conclusion, a technique based on angiographic image data for quantifying NMR was validated using a swine model. This study provides a method to measure NMR without using a velocity wire, which can potentially be used to evaluate microvascular conditions during coronary arteriography.

Impact of hinge motion on in-stent restenosis after sirolimus-eluting stent implantation.

BACKGROUND: A tortuous lesion with hinge motion is reportedly a risk factor for in-stent restenosis (ISR) after bare metal stent implantation. Sirolimus-eluting stents (SESs) implantation has dramatically reduced ISR. However, SES is a closed-cell design stent, which has low conformability and flexibility. Several studies have reported a relationship between tortuous lesions and stent fracture, which is one of the causes of ISR. The efficacy of SES in a tortuous lesion with hinge motion has not been fully evaluated. The aim of this study was to investigate the relationship between tortuous lesions and ISR after SES implantation. METHODS AND RESULTS: Three year clinical follow-up data after SES implantation, including 6-9 month scheduled follow-up coronary angiography in 399 consecutive patients with 537 lesions, were obtained. Δangle was defined as the difference in the angle of the target lesion between the diastole and systole before the procedure. The incidence of ISR was 8.2%. The mean maximal angle and Δangle were larger in the ISR group (47 ± 22° vs. 37 ± 21°, P=0.004 and 20 ± 13° vs. 13 ± 10°, P < 0.0001, respectively). Independent predictors of ISR were Δangle, hemodialysis, aortic ostium stenting, and diabetes mellitus. Hinge motion-associated ISR (Δangle ≥ 16°) occurred in 28 lesions: stent fracture in 9, stent recoil in 6, edge injury in 10, and others in 3. CONCLUSIONS: The amount of hinge motion in tortuous lesions should be considered in the selection of drug eluting stent types.

First evaluation of real-time nitric oxide changes in the coronary circulation in patients with non-ischaemic dilated cardiomyopathy using a catheter-type sensor.

AIMS: No direct method has yet been developed to measure real-time plasma nitric oxide (NO) concentration in humans. In this study, we evaluated a new method for measuring plasma NO concentration in patients with dilated cardiomyopathy (DCM) and in normal controls using a catheter-type sensor. METHODS AND RESULTS: We simultaneously measured average peak velocity (APV) of the coronary artery flow and change in plasma NO concentration using the NO sensor placed in the great cardiac vein of 10 DCM patients and 10 control subjects. These evaluations were performed in response to sequential intracoronary infusions of acetylcholine (ACh, 10⁻8-10⁻6 M), N(G)-monomethyl-l-arginine (l-NMMA, 200 µmol) and co-infusion of ACh and l-NMMA. The change in plasma NO concentration in DCM patients was significantly impaired compared with the control group (P < 0.01). Pretreatment with l-NMMA completely suppressed the ACh-induced NO concentration, whereas APV in the left anterior descending coronary artery was partially suppressed in both groups. Plasma NO concentration reached its peak value later than the maximum APV following the injection of ACh (10⁻6 M) in both groups. CONCLUSION: The catheter-type NO sensor could be applied to clinically evaluate the endothelial function (i.e. reduced endothelium-derived NO bioavailability) in patients with cardiovascular diseases.

Serial angiographic findings and prognosis of stent fracture site without early restenosis after sirolimus-eluting stent implantation.

BACKGROUND: Stent fracture is one of the possible causes of in-stent restenosis after sirolimus-eluting stent (SES) implantation. However, long-term prognosis including late restenosis in stent fracture site without early restenosis remains unknown. The aim of this study is to investigate the risk of late restenosis at the stent fracture site without early restenosis after SES implantation. METHODS: We divided 366 patients with 490 lesions into 2 groups with or without stent fracture based on the first scheduled follow-up coronary angiography (fracture group, 21 lesions; nonfracture group, 469 lesions). The second scheduled follow-up coronary angiography (>15 months after SES implantation) was performed in 83 patients with 124 lesions. RESULTS: Target lesion revascularization due to late restenosis at the stent fracture site did not occur in the fracture group, but occurred in 5 lesions in the nonfracture group. At the first follow-up, minimal luminal diameter was significantly smaller and percentage diameter stenosis was significantly larger in the fracture group (1.98 ± 0.41 vs 2.52 ± 0.49 mm, P = .001 and 30.5% ± 13.1% vs 13.0% ± 8.8%, P < .0001, respectively). These differences were also present at the second follow-up (P = .01 and P = .007, respectively). In each group, there were no significant changes in minimal luminal diameter, percentage diameter stenosis, and late lumen loss between the first and second follow-up. CONCLUSIONS: Late restenosis was not observed in stent fracture sites without early restenosis during the midterm follow-up after SES implantation.

Advantage of next-generation frequency-domain optical coherence tomography compared with conventional time-domain system in the assessment of coronary lesion.

BACKGROUND: Intracoronary optical coherence tomography (OCT) is a high-resolution imaging modality used for evaluation of coronary lesion morphology. However, current time-domain OCT (TD-OCT) have a number of limitations with regard to both procedural usage and safety in the clinical setting. The next-generation frequency-domain OCT (FD-OCT), which has a much faster frame rate and pullback speed than TD-OCT, is expected to overcome these limitations. The aim of this study was to evaluate the feasibility and usability of next generation FD-OCT in the assessment of coronary lesions. METHODS: A comparison study was performed between FD-OCT and TD-OCT from the aspect of usability (set-up time), qualitatively (rate of clear image segment), and safety (adverse event) in 14 ischemic heart disease patients with 20 previously implanted coronary stents. RESULTS: The mean time of the OCT procedure in this study from setup to completion of image acquisition was 3.2 +/- 0.8 min for FD-OCT and 11.2 +/- 2.5 min for TD-OCT (P < 0.01). In qualitative image assessment, FD-OCT has the potential to yield a higher rate of clear image segments (CIS) than TD-OCT (99.4% vs. 80.8%, respectively; P < 0.01). In addition to these improved characteristics, there were no ischemic ECG changes or arrhythmia associated with FD-OCT. CONCLUSIONS: The next-generation intracoronary FD-OCT has better performance in the clinical setting and the potential to overcome several limitations of conventional TD-OCT systems.

Lipid-rich plaque and myocardial perfusion after successful stenting in patients with non-ST-segment elevation acute coronary syndrome: an optical coherence tomography study.

AIMS: Although some recent guidelines recommend an early invasive strategy for non-ST-segment elevation acute coronary syndrome (NSTEACS), several studies have failed to identify any benefit for very early intervention for NSTEACS. The no-reflow phenomenon may inhibit the expected benefit from very early recanalization for NSTEACS subjects. The aim of this study was to investigate whether optical coherence tomography (OCT) could predict no-reflow in patients with NSTEACS. METHODS AND RESULTS: This study comprised 83 consecutive patients with NSTEACS who underwent OCT and successful emergent primary stenting. On the basis of post-stent TIMI flow, patients were divided into two groups: no-reflow group (n = 14) and reflow group (n = 69). Thin-cap fibroatheroma (TCFA) was defined as a plaque presenting lipid content for >90 degrees , and with thinnest part of the fibrous cap measuring <70 microm. Thin-cap fibroatheroma were more frequently observed in the no-reflow group than in the reflow group (50% vs. 16%, P = 0.005). The frequency of the no-reflow phenomenon increases according to the size of the lipid arc in the culprit plaque. Final TIMI blush grade also deteriorated according to the increase in the lipid arc. A multivariable logistic regression model revealed that lipid arc alone was an independent predictor of no-reflow (odds ratio 1.018; CI 1.004-1.033; P = 0.01). CONCLUSION: Optical coherence tomography can predict no-reflow after percutaneous coronary intervention (PCI) in NSTEACS. The lipid contents of a culprit plaque may play a key role in damage to the microcirculation after PCI for NSTEACS. From our results, it is found that OCT is useful tool for stratifying risk for PCI for NSTEACS.

Morphology of exertion-triggered plaque rupture in patients with acute coronary syndrome: an optical coherence tomography study.

BACKGROUND: Plaque rupture and secondary thrombus formation play key roles in the onset of acute coronary syndrome (ACS). One pathological study suggested that the morphologies of plaque rupture differed between rest-onset and exertion-triggered rupture in men who experienced sudden death. The aim of the present study was to use optical coherence tomography to investigate the relationship in patients with ACS between the morphology of a ruptured plaque and the patient's activity at the onset of ACS. METHODS AND RESULTS: The study population was drawn from 43 consecutive ACS patients (with or without ST-segment elevation) who underwent optical coherence tomography and presented with a ruptured plaque at the culprit site. Patients were divided into a rest group and an exertion group on the basis of their activities at the onset of ACS. The thickness of the broken fibrous cap correlated positively with activity at the onset of ACS. The culprit plaque ruptured at the shoulder more frequently in the exertion group than in the rest group (rest 57% versus exertion 93%, P=0.014). The thickness of the broken fibrous cap in the exertion group was significantly higher than in the rest-onset group (rest onset: 50 microm [interquartile median 15 microm]; exertion: 90 microm [interquartile median 65 microm], P<0.01). CONCLUSIONS: The morphologies of exertion-triggered and rest-onset ruptured plaques differ in ACS patients. Our data suggest that a thin-cap fibroatheroma is a lesion predisposed to rupture both at rest and during the patient's day-to day activity, and some plaque rupture may occur in thick fibrous caps depending on exertion levels.

Predictors and prognosis of stent fracture after sirolimus-eluting stent implantation.

BACKGROUND: Stent fracture is a cause of in-stent restenosis (ISR) after sirolimus-eluting stent (SES) implantation, so this study investigated the incidence, predictors and prognosis of stent fracture. METHODS AND RESULTS: The 273 consecutive patients (364 lesions) after SES implantation and who had 6-9 month' scheduled follow-up coronary angiography (CAG) were divided into groups with and without stent fracture. Deltaangle was defined as the difference in the angle in the target lesion between diastole and systole before the procedure. The incidence of stent fracture was 4.9% (18 of 364 lesions). Deltaangle in the target lesion was larger in the fracture group (28.3 +/-11.5 degrees vs 12.3 +/-9.0 degrees , P<0.0001). Independent predictors of stent fracture were Deltaangle and total stent length. The rates of binary restenosis and target lesion revascularization (TLR) were higher in the fracture group (33% vs 4.0%, P=0.0002 and 28% vs 3.5%, P=0.0007, respectively). There were no major adverse cardiac events (MACE) in the fracture group during a mean 24-month follow-up after follow-up CAG. CONCLUSIONS: Predictors of stent fracture were Deltaangle and total stent length. Although stent fracture was associated with ISR and TLR, it was not associated with MACE during long-term follow-up.

Branch segment occlusion with acute myocardial infarction is a risk for left ventricular free wall rupture.

BACKGROUND: Patients with acute myocardial infarction (AMI) whose culprit lesion lies in a branch of the 3 major coronary arteries have well-preserved cardiac function. A first MI with preserved cardiac function is a risk factor for left ventricular free wall rupture (LVFWR), so the aim of this study was to investigate the possible relationship between AMI with branch segment occlusion and LVFWR. METHODS AND RESULTS: The 439 patients with AMI were retrospectively studied. They were divided into 2 groups: group B (n=70; segments 4 atrioventricular node artery, 4 posterior descending coronary artery, 8, 9, 10, 12, 14, or 15 according to the AHA classification), and group P (n=369; segments 1, 2, 3, 5, 6, 7, 11, or 13). Primary percutaneous coronary intervention (PCI) was more often performed in group P (75% vs 57%; P=0.0018). In-hospital mortality tended to be lower in group B (1.4% vs 6.2%; P=0.105). The incidence of LVFWR was significantly higher in group B (10.0% vs 1.6%; P=0.0002).By multivariate logistic regression analysis, 1-vessel disease, absence of primary PCI, branch segment occlusion, and age were identified as independent predictors of LVFWR. CONCLUSIONS: The incidence of LVFWR was higher in group B and branch segment occlusion was identified as an independent predictor of LVFWR.

Myocardial salvage for ST-elevation myocardial infarction with terminal QRS distortion and restoration of brisk epicardial coronary flow.

Recently, it has been reported that large infarcts associated with terminal QRS distortion (QRSDIS) on the admission electrocardiograms of patients with ST-elevation myocardial infarctions (STEMIs) may be caused by a failure to achieve thrombolysis in myocardial infarction (TIMI) grade 3 flow after primary percutaneous coronary intervention (PCI). However, the relationship between QRSDIS and final infarct size when TIMI grade 3 flow could be achieved by primary PCI is still unclear. Sixty-two consecutive patients with first anterior STEMI and who achieved TIMI grade 3 flow by primary PCI were classified into two groups according to the presence (Group A, n = 18) or absence (Group B, n = 44) of QRSDIS. Two weeks after the onset of acute myocardial infarction, Group A had a larger left ventricular (LV) end-systolic volume index (LVESVI) and a lower LV ejection fraction (LVEF) than Group B (LVESVI: 38 +/- 13 vs 31 +/- 12 ml/m(2), P = 0.025: LVEF: 42% +/- 10% vs 51% +/- 10%, P = 0.004). Through multivariate analysis, independent predictors of poor LV systolic function (LVEF < 40%) were determined to be the presence of QRSDIS (odds ratio 21.04, P = 0.021) and proximal left anterior descending artery occlusion (odds ratio 16.15, P = 0.033). Myocardial damage could not be reduced in patients experiencing STEMI with QRSDIS, even when TIMI grade 3 flow could be achieved by primary PCI, as much as in patients experiencing STEMI without QRSDIS.

Determination of culprit coronary artery branches using hemodynamic indices from angiographic images.

A recently reported angiographic technique for hemodynamic indices based on first-pass distribution analysis (FPA) could potentially be helpful for determining the culprit artery responsible for myocardial ischemia. The purpose of this study was to determinate the culprit coronary arterial branches based on coronary flow reserve (CFR) and fractional flow reserve (FFR) using only angiographic images. The study was performed in 14 anesthetized swine. Microspheres were injected into coronary arterial branches to create microvascular disruption. Stenosis was also created by inserting plastic tubings in LAD and LCX arterial branches. Adenosine was used to produce maximum hyperemia. Angiographic CFR (CFRa), relative angiographic CFR (rCFRa), and angiographic FFR (FFRa) were calculated by FPA. The diagnostic abilities of CFRa, rCFRa, and FFRa were compared in three models: (1) epicardial stenosis model (S), (2) microcirculation disruption model (M), and (3) combined(S + M) model by using the area under the ROC curve (AUC). The mean differences between FFRa and the pressure-derived FFR (FFRp) measurements were -0.01 ± 0.21 in S model (N = 37) and 0.01 ± 0.18 in M model (N = 53). From 225 measurements in S model, the AUCs for CFRa and FFRa were 0.720 and 0.918, respectively. From 262 measurements in M model and 238 measurements in (S + M) model, the AUCs for CFRa, rCFRa, FFRa were 0.744, 0.715, 0.959 and 0.806, 0.738, 0.995, respectively. The hemodynamic indices of the small branches (down to ~0.7 mm) could be measured using only angiographic image data. The application of FFRa could potentially provide a useful method to assess the severity of disease in coronary arterial branches.