Proximal Vessel Diameter Research Articles

Coronary artery morphometrics in Indians – An optical coherence tomography perspective

Abstract BACKGROUND: The diameter of the coronary artery is an important predictor of prognosis and long-term outcome after percutaneous coronary interventions. There are very limited data available about coronary artery dimensions in an Indian population. AIMS: The aim is to study the normal dimensions of the coronary artery segments in Indians without coronary artery disease using optical coherence tomography and to compare the dimensions in Indians with Western. METHODS: Two hundred patients who have undergone coronary angiography with an entirely normal coronary angiogram were included in our study. RESULTS: This study showed the diameter of vessels in males and females when taken together, the left main was larger in size, followed by the proximal left anterior descending, proximal right coronary artery, and proximal left circumflex, respectively. When the vessel diameter was indexed to body surface area (BSA), there was no statistical difference between males and females (P > 0.05). The computed value of proximal coronary artery diameter unadjusted for individual BSA, when compared to Caucasians, showed that Caucasians have larger coronary artery dimensions than Indians. However, when the proximal vessel diameter was indexed to BSA, there was no statistically significant difference between Indians and Caucasians (P > 0.05). CONCLUSIONS: We found that coronary artery size when indexed to BSA is not statistically different in Indian males and females and compared to Caucasians. However, with a smaller body habitus, Indians have smaller coronary arteries.

1249 Single-Center Outcomes of Onyx Frontier and Resolute Onyx Drug-Eluting Balloon Mounted Stents for Rescue Stenting for Acute Large Vessel Occlusion

INTRODUCTION: Mechanical thrombectomy (MT) is a common treatment for large vessel occlusions with recent literature expanding its indications. In cases where MT fails, rescue stenting may be necessary to achieve reperfusion; however, the absence of standardized techniques or devices poses a challenge. METHODS: A retrospective chart review was performed of all patients who underwent rescue stenting, in the setting of MT, using Onyx Frontier or Resolute Onyx stents at a single institution. Technical details, procedural complications, and patient outcomes were recorded for each case. RESULTS: In total, 21 Onyx Frontier and Resolute Onyx stents were deployed in 18 patients undergoing rescue stenting. Among these, 13 involved the use of Resolute Onyx stents, while 5 cases utilized Onyx Frontier stents. Stent locations included the middle cerebral artery (40%), internal carotid artery (15%), vertebral artery (20%), and basilar artery (25%). The average NIHSS score before MT was 13.83 (range 0-31). The median initial mRS score was 0, while the median mRS score at follow-up was 3. Successful reperfusion, as assessed by TICI scores, was achieved in 43.8% of patients for TICI 3, 43.8% for TICI 2C, and 12.5% for TICI 2B. The average proximal vessel diameter was 2.31 mm, and the most used stent length was 12 mm. Post-revascularization, 33% of patients experienced hemorrhage, of which only one patient (16.7%) had symptomatic hemorrhage due to vessel rupture necessitating hemicraniectomy. CONCLUSIONS: Onyx Frontier and Resolute Onyx stents are well-suited for rescue stenting in cases where aspiration and stentriever techniques fail during MT. These balloon-mounted drug-eluting stents exhibit excellent navigability, rendering them appropriate for rescue revascularization procedures. Our findings demonstrate that these stents confer a high degree of technical success and a low rate of intra- and post-procedural complications.

Clinical outcomes and predictors of restenosis in patients with femoropopliteal artery disease treated using polymer-coated paclitaxel-eluting stents or drug-coated balloons.

Both polymer-coated paclitaxel-eluting stents (PC-PESs) and drug-coated balloons (DCBs) are used in conjunction with endovascular therapy (EVT) for the treatment of peripheral artery disease (PAD). We aimed to identify the risk factors for the loss of patency following the use of PC-PES and DCB in a real clinical setting. We assessed the multi-center registry data of 151 lesions from 151 patients who underwent EVT for symptomatic PAD in the superficial femoral and proximal popliteal arteries using PC-PES or DCB. One-year primary patency (PP) and clinically driven target lesion revascularization (CD-TLR) were evaluated using Kaplan-Meier analysis. The predictive risk factors for 1-year outcomes were analyzed using the random survival forest method. PC-PES and DCB were used in 65 (43.0%) and 86 (57.0%) cases, respectively. There were no significant differences in 1-year PP or freedom from CD-TLR between PC-PES and DCB. PP occurred in 85.4% and 80.2% of cases in the PC-PES and DCB groups, respectively (log-rank p = 0.65), while freedom from CD-TLR was noted in 92.7% and 94.1% of cases in the PC-PES and DCB groups, respectively (log-rank p = 0.73). In order of importance, a Clinical Frailty Scale score ≥ 6, female sex, lower proximal vessel diameter, lower body mass index, and younger and older age were identified as predictive risk factors of restenosis in the PC-PES group. Peripheral artery calcification scoring system grade of ≥ 2, post-dissection pattern ≥ D, lower proximal and distal vessel diameter, and lesion length ≥ 100mm were identified as predictive risk factors of restenosis, in order of importance, in the DCB group. Both PC-PES and DCB were associated with favorable clinical outcomes within 1year in patients with femoropopliteal artery disease. Furthermore, several factors that could predict restenosis within 1year following the use of each device were detected.

Coronary artery dimensions in normal Indians

BackgroundDiameter of coronary artery is an important predictor of outcome after percutaneous coronary interventions and coronary artery bypass graft surgery. There is very limited data available about coronary artery dimensions in an Indian population. AimsTo study the normal dimensions of the coronary artery segments in Indians without coronary artery disease by using quantitative coronary angiography and also to compare the dimensions in Indians with Western. Material and method229 patients who have undergone coronary angiography with entirely normal coronary angiogram were included in our study. ResultsThis study showed the diameter of vessels in males and females when taken together the left main was larger in size followed by proximal LAD, proximal RCA & proximal LCX respectively (4.08±0.44mm, 3.27±0.23mm, 3.20±0.37mm, 2.97±0.37mm).When the vessel diameter was indexed to body surface area there was no statistical difference between male and female (p value>0.05). The computed value of proximal coronary artery diameter unadjusted for individual body surface area, when compared to Caucasians showed that Caucasians have larger coronary artery dimensions than Indians. But when the proximal vessel diameter was indexed to body surface area there was no statistical significant difference between Indians and Caucasians (p value>0.05). ConclusionsWe found that coronary artery size when indexed to body surface area is not statistically different in Indian males and females and compared to Caucasians. However with a smaller body habitus Indians have smaller coronary arteries.

Computational fluid dynamics of computed tomography angiography to detect the hemodynamic impact of intracranial atherosclerotic stenosis

In symptomatic intracranial atherosclerotic stenosis (ICAS), its hemodynamic impact may affect the risk of stroke recurrence, in addition to the degree of luminal stenosis. We therefore conducted a pilot study to evaluate the feasibility to delineate the hemodynamic impact of symptomatic ICAS lesions using computational fluid dynamics (CFD) models reconstructed based on computed tomography angiography (CTA) source images. Three-dimensional CFD models were reconstructed based on routine CTA source images of patients with a symptomatic ICAS lesion. The anatomic features and hemodynamic impact of target ICAS lesions were evaluated on the CFD models. The hemodynamic impact of a lesion was evaluated using distal to proximal pressure ratio (PR) and pressure gradient (PG) across the lesion. PG was defined as pressure drop across the lesion divided by length of the lesion. Among the 10 cases recruited, CTA source images of 9 cases were successfully processed to CFD models. The hemodynamic characteristics of the ICAS lesions could be quantitatively evaluated on the CFD models, such as the pressures, blood flow velocities, wall shear stress and shear strain rates. The median PR was 0.58 and the median PG was 93 mmHg/cm. PRs and PGs varied in cases with similar degrees of stenoses with different lesion lengths and proximal vessel diameters. This pilot study demonstrated the feasibility to quantitatively assess the hemodynamic impact of ICAS using CFD models reconstructed based on routine CTA. Further studies are required to improve the models built in this pilot study, and to evaluate the ultimate value of this technique in clinical assessment and risk stratification of patients with symptomatic ICAS.

Plasma alkylresorcinols, biomarkers of whole-grain intake, are not associated with progression of coronary artery atherosclerosis in postmenopausal women with coronary artery disease.

The objective of the present study was to examine the relationship between plasma alkyresorcinol (AR) concentrations, which are biomarkers of whole-grain intake, and atherosclerotic progression over 3 years in postmenopausal women with coronary artery disease. Plasma AR concentrations were measured by a validated GC-MS method in fasting plasma samples. Atherosclerosis progression was assessed using change in mean minimal coronary artery diameter (MCAD) and percentage diameter stenosis (%ST), based on mean proximal vessel diameter across up to ten coronary segments. Dietary intake was estimated using a 126-item interviewer-administered FFQ. A prospective study of postmenopausal women participating in the Estrogen Replacement and Atherosclerosis trial. For the analysis of plasma AR concentrations and atherosclerotic progression, plasma samples and follow-up data on angiography were available for 182 women. Mean whole-grain intake was 9·6 (se 0·6) servings per week. After multivariate adjustment, no significant associations were observed between plasma AR concentrations and change in mean MCAD or progression of %ST. Plasma AR concentrations were significantly correlated with dietary whole grains (r=0·35, P<0·001), cereal fibre (r=0·33, P<0·001), bran (r=0·15, P=0·05), total fibre (r=0·22, P=0·003) and legume fibre (r=0·15, P=0·04), but not refined grains, fruit fibre or vegetable fibre. Plasma AR concentrations were not significantly associated with coronary artery progression over a 3-year period in postmenopausal women with coronary artery disease. A moderate association was observed between plasma AR concentrations and dietary whole grains and cereal fibre, suggesting it may be a useful biomarker in observational studies.

Predictors and Outcomes of Recurrent Stent Thrombosis

The aim of this study was to determine the incidence, predictors, and outcomes of recurrent stent thrombosis (rST). Patients who had an initial stent thrombosis (ST) develop may be at high risk of rST. We analyzed a multicenter California registry of angiographic definite ST at 5 academic hospitals from 2005to 2013. A detailed review of the angiogram and procedure was performed of patients with and without rST. Among 221 patients with a median follow-up of 3.3 years, definite or probable rST developed in 29, including 19 with angiographic definite rST. The cumulative hazard ratio (HR) of definite or probable rST was 16% at 1 year and 24% at 5 years, whereas the cumulative HR of angiographic definite rST was 11% at 1 year and 20% at 5 years. Despite similar angiographic results, patients who had rST develop had significantly greater peak creatine kinase at the time of initialST (mean, 2,655 mg/dl vs. 1,654 mg/dl; p= 0.05) than those without rST. The 3-year rate of major adverse cardiovascular events was 50% for patients with rST compared with 22% for patients with a single ST (p= 0.01). After multivariable adjustment, independent predictors of definite/probable rST were age (HR: 1.4; 95 confidence interval [CI]: 1.1 to 1.8 per 10 years), bifurcation ST (HR: 4.4; 95% CI: 1.8 to 10.9), and proximal vessel diameter (HR: 1.8; 95% CI: 1.1 to3.2 per millimeter). rST represents an important cause of long-term morbidity and mortality after an initial ST. Bifurcation ST and a larger proximal reference vessel diameter are independently associated with an increased risk of rST.

Testing the packing rule across the twig–petiole interface of temperate woody species

Theories that incorporate the area-preserving rule of Leonardo da Vinci predict that the sum of the cross-sectional lumen area of xylem conduits (vessels or tracheids) is constant across different levels of branching. If true, this rule obtains the packing rule, according to which (1) vessel cross-sectional lumen area (A) will negatively and isometrically scale to vessel number per unit area (N) and (2) the distal to proximal vessel diameter ratio (DR = D (n+1)/D (n) ) should scale as the -1/2 power of the distal to proximal vessel number ratio (NR = N (n+1)/N (n) ), i.e., DR = NR-1/2. Using data collected from the terminal twigs and the petioles of 60 temperate (27 evergreen and 33 deciduous) woody species from southwestern China, we determined the scaling relationships for A versus N and for DR versus NR. Analyses of the data revealed contrasting scaling exponents and normalization constants for A versus N and for DR versus NR and no consistent trend across the two species groupings or between the two organ types (as predicted by the area-preserving and packing rules). These results caution against applying these rules ubiquitously to all species or to different organ types (even on the same plant).

Feasibility of intraventricular nicardipine prolonged release implants in patients following aneurysmal subarachnoid haemorrhage

Objective. Intracisternal nicardipine prolonged release implants (NPRI) have been shown to be effective in the prophylaxis of cerebral vasospasm (VS). However, they cannot be used in patients following coil occlusion of the aneurysm. As a certain dissemination of nicardipine within the cerebrospinal fluid (CSF) has been described, we examined the feasibility of intraventricular use of NPRI in patients that underwent clip and coil occlusion of their aneurysms following aneurysmal subarachnoid haemorrhage (aSAH). By comparison with an historical control group, an estimation of their effectivity in regard to angiographic vasospasm and the development of cerebral infarction has been performed.Methods. Thirty-one patients suffering from aSAH were prospectively included in this trial. Study participants received prior to clipping (n = 17) or coiling (n = 14) 6 (n = 15) or 10 NPRI (n = 16) into the lateral ventricles. Physiological data were collected, proximal and global VS were determined using pre-operative and day 8 ± 1 angiography, and incidence of hydrocephalus and VS related infarcts were evaluated and compared to a historical control group consisting of 16 operated patients without NPRI implantation.Results. Intraventricular NPRI were tolerated well. There were no adverse side effects detectable, physiological variables such as heart rate (HR), mean arterial blood pressure (MAP), intracranial pressure (ICP) and electrolytes showed no difference compared to control. There was no difference in the proportion of patients that required CSF shunting. A significant positive angiographic effect could only be observed in clipped patients (proximal vessel diameters: control, 80 ± 30%; NPRI 90 ± 24%; incidence of moderate/severe global VS: control, 73%; NPRI, 41%).Conclusions. The use of intraventricular NPRI seems to be safe and tolerated well. There is preliminary evidence for effectivity on angiographic VS for clipped patients only. A further increase of the effective dose might also exert efficacy in the subset of patients following coil occlusion.

The long-term effects of transluminal balloon angioplasty for vasospasms after subarachnoid hemorrhage: analyses of cerebral blood flow and reactivity

Background Transluminal balloon angioplasty (TBA) has come into wide use for management of symptomatic cerebral vasospasm after subarachnoid hemorrhage (SAH). The long-term effects of TBA in this clinical context on cerebral blood flow (CBF) and the functional properties of the arterial wall after aneurysmal SAH remain controversial. We therefore studied these effects. Methods All patients underwent unilateral TBA. Xenon-enhanced computed tomography was performed for an average of 18 days after TBA to measure CBF and cerebrovascular reactivity (CVR). Cerebral blood flow and CVR were compared between the side of TBA and the contralateral side. Results Nineteen vascular territories were treated successfully with TBA in 12 patients. Angiographic improvement of vasospasm was demonstrated in all 12 patients, and 9 (75%) patients showed neurological improvement. After balloon angioplasty, global CBF was 35.1 ± 8.2 mL/100 g per minute, with CBF on the side with TBA (37.8 ± 10.3 mL/100 g per minute) being essentially the same as that on the other side ( P = .0671, paired Student t test). Likewise, reactivity to acetazolamide did not differ significantly between sides ( P = .0817). Conclusion Transluminal balloon angioplasty increased proximal vessel diameters but showed no significant influence on CBF or vascular reactivity 3 weeks later. Benefits presumably were short term, but the procedure was clinically safe.

Anomalies of the abdominal aorta in Williams-Beuren syndrome--another cause of arterial hypertension.

Vascular disease in Williams-Beuren syndrome is based on an elastin arteriopathy which may cause stenoses in small and great vessels. This study presents the pattern of stenotic lesions of the abdominal aorta and the incidence of arterial hypertension. From 112 patients with Williams-Beuren syndrome followed since 1975, 25 patients were studied by aortography. The diameter of the thoracic aorta and the change in diameter to the iliac bifurcation were compared with normal data. Renal artery stenosis was suspected when the proximal vessel diameter was less than 50% of the distal diameter. Of the 25 patients, 20 had vascular stenosis of whom 19 patients were affected by segmental narrowing either of the thoracic aorta (n=9) or the abdominal aorta (n = 7) or both (n = 3). Hypoplasia of the abdominal aorta was characterised by the smallest diameters at the renal artery level and an increased diameter of the infrarenal abdominal aorta. A total of 11 patients had renal arterial stenosis, associated with narrowing of other aortic segments in 10 cases. Only one patient had a solitary stenosis of the renal artery. Arterial hypertension was diagnosed in 17 patients, 2 of them had no vascular lesions; in the remaining 15 patients stenosis was present in more than one segment (aorta 6, renal artery stenosis 1, both 8). Narrowing of the abdominal aorta in patients with Williams-Beuren syndrome is a frequent morphological manifestation of the arteriopathy. Isolated renal arterial stenosis was rare, since it was more frequently combined with a narrowed aorta. Hypertension is a common symptom in the affected group and must be regarded as a manifestation of generalised arteriopathy rather than renal hypoperfusion.

Importance of Nitric Oxide in the Coronary Artery at Rest and During Pacing in Humans

Objectives. The purpose of this study was to investigate the role of endothelium-dependent vascular regulation in the human coronary circulation during rest and hyperemic states.Background. Evidence of the role of nitric oxide (NO) during metabolic demand is not consistent in animal and human coronary circulation.Methods. NG-Monomethyl-l-arginine (l-NMMA), a specific inhibitor of NO synthesis, was infused into the left anterior descending coronary artery at rest and during rapid atrial pacing in 18 subjects—9 with normal coronary arteries (control) and 9 with atherosclerotic coronary arteries. The diameter of the epicardial coronary artery was measured by quantitative coronary angiography. Vasodilation of the coronary microcirculation was assessed using an intracoronary Doppler FloWire.Results. Infusion of 25 μmol/min of l-NMMA reduced the diameter of the proximal and distal epicardial coronary artery segments by 8 ± 2% (mean ± SE) and 11 ± 2%, respectively (p < 0.05) in the control subjects. The coronary blood flow (CBF) decreased by 33 ± 13% during l-NMMA infusion. l-NMMA caused similar changes in the diameter of the distal epicardial segment and the CBF in patients with coronary artery disease. The proximal vessel diameter did not change significantly during infusion of l-NMMA. During pacing, infusion of l-NMMA caused the same changes in vessel diameter as before pacing in both groups, but did not affect CBF.Conclusions. Our findings indicate that NO synthesis maintains basal vasomotor tone in both conduit and resistance vessels in the normal human coronary circulation. Although NO release was impaired in the large epicardial coronary arteries in patients with atherosclerosis, NO still regulated vascular tone in the small epicardial coronary arteries and arterioles. Our results suggest that vasodilation in arterioles during increased myocardial oxygen demand is mediated by metabolic or myogenic mechanisms, or both, rather than by endothelium-dependent production of NO.(J Am Coll Cardiol 1997;29:85–92)>

Morphological predictors of acute complications after percutaneous excimer laser coronary angioplasty. Results of a comprehensive angiographic analysis: importance of the eccentricity index.

Percutaneous excimer laser coronary angioplasty (ELCA) is a new technique for recanalization of arteries obstructed by coronary atherosclerosis. This study was conducted to assess the complication rate and determine the influence of clinical and angiographic characteristics on complications after ELCA. A detailed, quantitative, angiographic core laboratory analysis of patients undergoing ELCA was performed by two experienced angiographers who were not the primary laser angioplasty operators. Two hundred patients underwent 203 separate procedures on 220 lesions at three medical centers. Laser success was achieved in 180 lesions (81.8%) and procedural success in 199 (90.5%). Emergency coronary artery bypass graft (CABG) was required in five patients (2.5%). One patient suffered a Q wave myocardial infarction; there were no deaths. Also, acute closure and perforation occurred in 10 (4.5%) and three (1.4%) vessels, respectively. Coronary dissections after laser treatment were seen in 36 vessels (16.4%). Multivariate analysis found two independent preprocedural factors related to complications: eccentricity index, which is the percent deviation of the lesion lumen from the center of the artery (p = 0.0007), and proximal vessel diameter (p = 0.033). In addition, an abrupt proximal face of the lesion was associated with angiographic complications by univariate analysis (p = 0.051). Multivariate analysis showed the eccentricity index (p = 0.032) to be the only independent predictor for the occurrence of any one or more of the important complications (emergency CABG, perforation, acute closure, or Q wave myocardial infarction), whereas lesion angle greater than 45 degrees was a significant univariate predictor (p = 0.029). Other predictors of complications with balloon percutaneous transluminal coronary angioplasty, such as increased lesion length, rough edges, calcification, ulceration, and branch point, were not predictive of complications with the excimer laser. The degree of lesion eccentricity is the most powerful predictor of complications after ELCA. This and other morphological predictors may be of benefit in the selection of patients for ELCA as well as directing future development of this new technology.

Effects of a stabilized endothelium-derived relaxing factor on the coronary vasculature in awake dogs

The effects of a partially purified endothelium-derived relaxing factor (EDRF) stabilized by acidification from cultured bovine aortic endothelial cells stimulated with the calcium ionophore A23187 on coronary and peripheral vasculature were examined in five awake dogs. The dogs were chronically instrumented with miniature arterial dimension crystals and Doppler flow probes. Intracoronary or intra-arterial infusions of this EDRF induced a rapid (less than 15 s) significant increase in the proximal vessel diameter (P less than 0.02). The duration of proximal dilation response to this EDRF persisted up to 6 min, whereas the smaller changes in distal flow were more transient (less than 1 min). Similar but more pronounced changes in the proximal arterial dilation and distal flow occurred with infusion of nitroglycerin (0.4 mg). No vasoactive changes were observed during infusions of the control vehicle. The vasodilatory effects to this EDRF occurred in the absence of changes in aortic and left ventricular pressure, rate of pressure development (dP/dt), and heart rate. These data demonstrate that infusion of this partially purified relaxing factor from cultured endothelial cells causes vasodilation in vivo with a vasoactive profile similar to nitroglycerin. The biological effects of this EDRF persist significantly longer than the extreme lability of EDRF at neutral pH (approximately 6 s), consistent with its in vitro effects. Despite the demonstration of rapid inactivation of EDRF in vitro by hemoglobin, high oxygen tension, and plasma, the study shows that this EDRF can have significant in vivo vasoactive effects.