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Biomedical subjects

Peter J Fitzgerald

Publications and source records attributed to Peter J Fitzgerald.

At least 19 recordsLinked to original sources
PubMed2006

Comparison of zotarolimus-eluting and sirolimus-eluting stents in patients with native coronary artery disease: a randomized controlled trial.

OBJECTIVES: This trial examined the relative clinical efficacy, angiographic outcomes, and safety of zotarolimus-eluting coronary stents (ZES) with a phosphorylcholine polymer versus sirolimus-eluting stents (SES). BACKGROUND: Whether a cobalt-based alloy stent coated with the novel antiproliferative agent, zotarolimus, and a phosphorylcholine polymer may provide similar angiographic and clinical benefit compared with SES is undetermined. METHODS: A prospective, multicenter, 3:1 randomized trial was conducted to evaluate the safety and efficacy of ZES (n = 323) relative to SES (n = 113) in 436 patients undergoing elective percutaneous revascularization of de novo native coronary lesions with reference vessel diameters between 2.5 mm and 3.5 mm and lesion length > or =14 mm and < or =27 mm. The primary end point was 8-month angiographic in-segment late lumen loss. RESULTS: Angiographic in-segment late lumen loss was significantly higher among patients treated with ZES compared with SES (0.34 +/- 0.44 mm vs. 0.13 +/- 0.32 mm, respectively; p < 0.001). In-hospital major adverse cardiac events were significantly lower among patients treated with ZES (0.6% vs. 3.5%, p = 0.04). In-segment binary angiographic restenosis was also higher in the ZES cohort (11.7% vs. 4.3%, p = 0.04). Total (clinically and non-clinically driven) target lesion revascularization rates at 9 months were 9.8% and 3.5% for the ZES and SES groups, respectively (p = 0.04). However, neither clinically driven target lesion revascularization (6.3% zotarolimus vs. 3.5% sirolimus, p = 0.34) nor target vessel failure (12.0% zotarolimus vs. 11.5% sirolimus, p = 1.0) differed significantly. CONCLUSIONS: Compared with SES, treatment with a phosphorylcholine polymer-based ZES is associated with significantly higher late lumen loss and binary restenosis at 8-month angiographic follow-up. (The Endeavor III CR; http://clinicaltrials.gov/ct/show/NCT00265668?order=1?).

Aged↗
PubMed2006

Comparison of the efficacy of direct coronary stenting with sirolimus-eluting stents versus stenting with predilation by intravascular ultrasound imaging (from the DIRECT trial).

A direct coronary stenting technique using drug-eluting stents may decrease drug-eluting stent efficacy due to possible damage to the surface coating of the stent. The DIRECT is a multicenter, prospective, nonrandomized trial designed to evaluate the direct stenting strategy for the sirolimus-eluting Bx-Velocity stent compared with the historical control (SIRIUS trial, stenting with predilation). Volumetric and cross-sectional intravascular ultrasound analyses at 8-month follow-up were performed in 115 patients (DIRECT n= 64, control n = 51). Patient and lesion characteristics were comparable between groups. The DIRECT group achieved an equivalent uniform expansion index, defined as minimum stent area/maximum stent area x 100, compared with the control group (65.9 +/- 11.7 vs 63.1 +/- 12.7, p = NS). At 8-month follow-up, vessel, stent, lumen, and neointimal volume index (volume in cubic millimeters/length in millimeters) and percent neointimal volume were similar between the DIRECT and control groups (vessel volume index 13.9 +/- 4.40 vs 15.0 +/- 3.83; stent volume index 6.83 +/- 2.02 vs 6.94 +/- 2.04; lumen volume index 6.71 +/- 2.04 vs 6.81 +/- 2.07; neointimal volume index 0.14 +/- 0.24 vs 0.16 +/- 0.23; percent neointimal volume 3.73 +/- 6.97 vs 3.14 +/- 5.32, p = NS for all). In addition, in-stent neointimal hyperplasia distribution was significantly smaller near the distal stent edge (0.22 vs 0.098 mm(3)/mm, p = 0.01 for an average neointimal volume index within 3 mm from the distal stent edge). In conclusion, direct coronary stenting with the sirolimus-eluting Bx-Velocity stent is equally effective in terms of uniform stent expansion and long-term quantitative intravascular ultrasound results compared with conventional stenting using predilation. This strategy appears to be associated with less neointimal hyperplasia near the distal stent edge.

Coronary Stenosis↗
PubMed2006

Randomized, double-blind, multicenter study of the Endeavor zotarolimus-eluting phosphorylcholine-encapsulated stent for treatment of native coronary artery lesions: clinical and angiographic results of the ENDEAVOR II trial.

BACKGROUND: The use of the Endeavor stent might reduce restenosis and stent thrombosis at 9 months. METHODS AND RESULTS: Patients (n = 1197) treated for single coronary artery stenosis were enrolled in a prospective, randomized, double-blind study and randomly assigned to receive the Endeavor zotarolimus-eluting phosphorylcholine polymer-coated stent (n = 598) or the same bare metal stent but without the drug or the polymer coating (n = 599). The 2 groups were well matched in baseline characteristics. Diabetes was present in 20.1% of patients; the mean reference vessel diameter was 2.75 mm; and the mean lesion length was 14.2 mm. The primary end point of target vessel failure at 9 months was reduced from 15.1% with the bare metal stent to 7.9% with the Endeavor (P = 0.0001), and the rate of major adverse cardiac events was reduced from 14.4% with the bare metal stent to 7.3% with the Endeavor (P = 0.0001). Target lesion revascularization was 4.6% with Endeavor compared with 11.8% with the bare metal stent (P = 0.0001). The rate of stent thrombosis was 0.5% with the Endeavor, which was not significantly different from 1.2% with the bare metal stent. In 531 patients submitted to angiographic follow-up, late loss was reduced from 1.03 +/- 0.58 to 0.61 +/- 0.46 (P < 0.001) in stent and from 0.72 +/- 0.61 to 0.36 +/- 0.46 (P < 0.001) in segment. The rate of in-segment restenosis was reduced from 35.0% to 13.2% with Endeavor (P < 0.0001). There was no excessive edge stenosis, aneurysm formation, or late acquired malapposition by intravascular ultrasound imaging. Differences in clinical outcome were maintained at 12 and 24 months (P < 0.0001). CONCLUSIONS: Compared with bare metal stents, the Endeavor stent is safe and reduces the rates of clinical and angiographic restenosis at 9, 12, and 24 months.

Aged↗
PubMed2006

Effect of everolimus-eluting stents in different vessel sizes (from the pooled FUTURE I and II trials).

The everolimus-eluting stent (EES) has been shown to significantly decrease neointimal proliferation at 6 months compared with the bare metal stent (BMS) in patients with de novo coronary lesions. We report mid-term outcomes based on different vessel sizes in the combined FUTURE I and II trials. In the prospective, randomized, FUTURE I trial (single center) and expanded FUTURE II trial (multicenter), 106 patients (107 lesions) were randomized to EESs (n = 49 lesions) or BMSs (n = 58 lesions). Patients were categorized into 3 groups based on preprocedure reference diameter as assessed by quantitative coronary angiography (small vessel < 2.75 mm, medium vessel 2.75 to 3.25 mm, and large vessel > 3.25 mm). At 6-month follow-up, EESs decreased in-stent late lumen loss (decreased rate range of 78% to 94%), resulting in significantly larger minimum lumen area as assessed by intravascular ultrasound (increased range of 34% to 42%) compared with the BMS across all vessel sizes. There were no cases of in-stent restenosis with EESs at any vessel size but 8 cases with BMSs (5 in small vessels). No stent thrombosis, aneurysm formation, or late stent incomplete apposition was observed in any group. The EES appears to be effective for treatment of de novo coronary lesions in decreasing neointimal proliferation at 6-month follow-up compared with BMSs, regardless of vessel size.

Aged↗
PubMed2006

Discordant changes in epicardial and microvascular coronary physiology after cardiac transplantation: Physiologic Investigation for Transplant Arteriopathy II (PITA II) study.

BACKGROUND: Investigating changes in coronary physiology that occur after cardiac transplantation has been challenging. Simultaneous and independent assessment of the epicardial artery by measuring fractional flow reserve (FFR) and of the microvasculature by calculating the index of microvascular resistance (IMR) with a single coronary pressure wire may be useful. METHODS: Twenty-five asymptomatic patients with normal coronary angiograms underwent FFR, thermodilution-derived IMR and coronary flow reserve (CFR) and intravascular ultrasound (IVUS) evaluation soon after cardiac transplantation and 1 year later. RESULTS: FFR significantly worsened (0.90 +/- 0.05 at baseline to 0.85 +/- 0.06 at 1 year, p = 0.004). FFR correlated strongly with percent plaque volume as measured by IVUS (r = -0.58, p < 0.0001). IMR improved significantly (29.2 +/- 15.9 at baseline to 19.3 +/- 7.6 units at 1 year, p = 0.007). CFR increased, but not significantly (2.6 +/- 1.4 at baseline to 3.2 +/- 1.2 at 1 year, p = not significant). Diabetes and donor heart ischemic time independently predicted baseline IMR. Treatment with rapamycin independently predicted FFR at 1 year. CONCLUSIONS: New coronary physiologic measures, FFR and IMR, show that epicardial artery physiology worsens and correlates with anatomic changes, whereas microvascular physiology improves during the first year after cardiac transplantation. CFR, the traditional method for evaluating coronary circulatory physiology, did not identify these changes.

Cardiac Catheterization↗
PubMed2006

Intravascular ultrasonic analysis of atherosclerotic vessel remodeling and plaque distribution of stenotic left anterior descending coronary arterial bifurcation lesions upstream and downstream of the side branch.

Bifurcation lesions remain a challenging lesion subset, even in the era of drug-eluting stents. The aim of this study was to investigate the longitudinal remodeling pattern and cross-sectional plaque location of bifurcation lesions. Seventy-four preintervention intravascular ultrasound studies of left anterior descending bifurcation lesions were analyzed, in which the lesion was located proximal (type A, n=32) or distal (type B, n=42) to the side branch. Vessel area and plaque area at the lesion (VAlesion and PAlesion) and at the reference site (VAreference and PAreference) were measured. The remodeling ratio was defined as VAlesion/VAreference, and the vessel compensation ratio was defined as (VAlesion-VAreference)/(PAlesion-PAreference). The geometric center of the lumen at the lesion site was identified, and the lesion site was divided into circumferential equal arcs to compare the cross-sectional distribution of percentage plaque area (100x[PAlesion/VAlesion]) between the 2 groups. The remodeling ratio (1.03+/-0.15 vs 0.94+/-0.14, p=0.01) and the vessel compensation ratio (0.0+/-0.36 vs -0.37+/-0.61, p<0.01) were significantly greater in type A than in type B lesions. The circumferential distribution pattern of percentage plaque area was significantly different between the groups (analysis of variance p<0.005), with greater percentage plaque area for the vessel wall opposite from the side branch in type B lesions (46.3+/-18.0% vs 54.6+/-15.4%, type A vs type B lesions, p<0.05). In conclusion, these results suggest that a major side branch may affect longitudinal lesion remodeling as well as the circumferential location of atherosclerotic plaque.

Coronary Artery Disease↗
PubMed2006

Location of focal vasospasm provoked by ergonovine maleate within coronary arteries in patients with vasospastic angina pectoris.

This study examined whether coronary focal vasospasm occurs in a nonuniform distribution within the coronary tree and whether a longitudinal plaque distribution pattern is present in patients with vasospastic angina using 3-dimensional intravascular ultrasound analysis. Of 121 patients with clinically suspected angina without fixed stenosis in the coronary arteries, vasospasm was provoked in 82 patients with 92 lesions (42 focal, 50 diffuse) by intravenous ergonovine maleate injection. Most focal vasospasms occurred in the proximal third of the coronary arteries (proximal 28, mid 8, distal 6, p <0.01), corresponding to the historical high-risk zones for acute coronary occlusion. More plaque burden also existed in the proximal third of the coronary arteries in patients with focal vasospasm.

Angina Pectoris↗
PubMed2006

Sirolimus-eluting stents vs vascular brachytherapy for in-stent restenosis within bare-metal stents: the SISR randomized trial.

CONTEXT: Although vascular brachytherapy is the only approved therapy for restenosis following bare-metal stent implantation, drug-eluting stents are now being used. Data on the relative merits of each are limited. OBJECTIVE: To determine the safety and efficacy of the sirolimus-eluting stent compared with vascular brachytherapy for the treatment of patients with restenosis within a bare-metal stent. DESIGN, SETTING, AND PATIENTS: Prospective, multicenter, randomized trial of 384 patients with in-stent restenosis who were enrolled between February 2003 and July 2004 at 26 academic and community medical centers. Data presented represent all follow-up as of June 30, 2005. INTERVENTIONS: Vascular brachytherapy (n = 125) or the sirolimus-eluting stent (n = 259). MAIN OUTCOME MEASURE: Target vessel failure (cardiac death, myocardial infarction, or target vessel revascularization) at 9 months postprocedure. RESULTS: Baseline patient characteristics were well matched. Lesion length was similar between vascular brachytherapy and sirolimus-eluting stent patients (mean [SD], 16.76 [8.55] mm vs 17.22 [7.97] mm, respectively; P = .61). Procedural success was 99.2% (124/125) in the vascular brachytherapy group and 97.3% (250/257) in the sirolimus-eluting stent group (P = .28). The rate of target vessel failure was 21.6% (27/125) with vascular brachytherapy and 12.4% (32/259) with the sirolimus-eluting stent (relative risk [RR], 1.7; 95% confidence interval [CI], 1.1-2.8; P = .02). Target lesion revascularization was required in 19.2% (24/125) of the vascular brachytherapy group and 8.5% (22/259) of the sirolimus-eluting stent group (RR, 2.3 [95% CI, 1.3-3.9]; P = .004). At follow-up angiography, the rate of binary angiographic restenosis for the analysis segment was 29.5% (31/105) for the vascular brachytherapy group and 19.8% (45/227) for the sirolimus-eluting stent group (RR, 1.5 [95% CI, 1.0-2.2]; P = .07). Compared with the vascular brachytherapy group, minimal lumen diameter was larger in the sirolimus-eluting stent group at 6-month follow-up (mean [SD], 1.52 [0.63] mm vs 1.80 [0.63] mm; P<.001), reflecting greater net lumen gain in the analysis segment (0.68 [0.60] vs 1.0 [0.61] mm; P<.001) due to stenting and no edge restenosis. CONCLUSION: Sirolimus-eluting stents result in superior clinical and angiographic outcomes compared with vascular brachytherapy for the treatment of restenosis within a bare-metal stent. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT00231257.

Aged↗
PubMed2006

Acute and long-term outcomes of the novel side access (SLK-View) stent for bifurcation coronary lesions: a multicenter nonrandomized feasibility study.

OBJECTIVE: To evaluate technical feasibility and procedural safety of SLK-View stent for treating bifurcation lesions. BACKGROUND: Percutaneous treatment of coronary bifurcation lesions represents a technical challenge. Several stenting techniques and dedicated devices have proven unsuccessful, with high rates of side branch occlusion at index procedure and follow-up. METHODS: Eighty one patients with 84 de novo coronary artery lesions involving a major side branch underwent SLK-View (Advanced Stent Technologies, Inc., Pleasanton, CA) stent implantation with subsequent kissing balloon post dilatation. SLK-View stent is a new scaffolding device incorporating a side aperture that allows access to the side-branch of a bifurcation after deployment of the stent in main vessel. All patients underwent angiographic follow-up at 6 months. Procedural, in-hospital, and 6-month follow-up outcomes were examined. RESULTS: The lesions were located in left main (n = 11), left anterior descending (n = 50), left circumflex (n = 8), right coronary artery (n = 7), and 1 ramus intermedius. The most frequent lesions (44.1%) were true bifurcations. Successful stent delivery to bifurcation was accomplished in 82/84 of the cases (97.6%). Technical success was obtained in 99 and 94% of main vessel and side branches, respectively. Stenting in side-branch was performed in 21 lesions (25%). Side-branches were accessed effectively in 100% of bifurcations postprocedurally. Binary restenosis rate at 6-month follow-up was 28.3% and 37.7% for main vessel and side-branch, respectively. TLR rate at 6-month follow-up was 21% and CABG rate of 6%. CONCLUSION: In this consecutive multicenter series of patients with coronary bifurcation lesions, this novel side-branch access stent proved feasible, with a high procedural success rate, while maintaining side-branch access.

Angioplasty, Balloon↗
PubMed2006

Latent plaque rupture in a patient undergoing stenting for acute coronary syndrome and diffuse coronary disease: a case report and review of literature.

Secondary prevention of plaque rupture following percutaneous coronary intervention in patients with acute coronary syndrome is not well studied. This case report describes a 53-year-old man who experienced plaque rupture between two previously successfully implanted stents in the right coronary artery, as documented during the 3rd intervention using intravascular ultrasound.

Aneurysm↗
PubMed2006

Influence of plaque calcium on neointimal hyperplasia following bare metal and drug-eluting stent implantation.

OBJECTIVES: To examine the influence of vessel wall calcium on neointimal hyperplasia (NIH) following bare metal stent (BMS) and drug-eluting stent (DES) implantation. BACKGROUND: While procedural complications with coronary stenting in calcified lesions are well reported, little is known about subsequent NIH on plaque calcium following either BMS or DES implantation. METHODS: In the Study to COmpare REstenosis Rate between QueST and QuaDDS-QP2 (SCORE) trial, 6 months follow-up volumetric intravascular ultrasound data were available for 41 lesions (BMS, 19; DES, 22). NIH thicknesses on superficial, deep, and noncalcified plaque were calculated at every 0.5 mm intervals over the stented segment. Calcified and less-calcified cross-sections were defined as those containing arcs of plaque calcium > or = 90 degrees and < 90 degrees , respectively. RESULTS: In BMS, mean NIH thickness on both superficial (0.24 +/- 0.23 mm) and deep calcium (0.25 +/- 0.21 mm) was significantly smaller than that of noncalcified plaque (0.31 +/- 0.22 mm) (P < 0.0005). NIH area was significantly smaller in calcified cross-sections compared to less-calcified cross-sections (2.1 +/- 1.2 mm2 vs. 3.1 +/- 1.9 mm2, P < 0.0001). While in contrast, in DES, mean NIH thickness was similar, irrespective of the presence or location of calcium (0.03 +/- 0.05 mm vs. 0.03 +/- 0.06 mm vs. 0.03 +/- 0.05 mm, superficial vs. deep vs. noncalcified plaque, P = NS). NIH area was also similar between calcified and less-calcified cross-sections (0.3 +/- 0.6 mm2 vs. 0.3 +/- 0.6 mm2, P = NS). CONCLUSIONS: These results suggest that while plaque calcium may influence NIH following BMS implantation, NIH suppression using DES does not appear to be affected by the presence or location of calcium.

Bridged-Ring Compounds↗
PubMed2006

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.

Aged↗
PubMed2006

Transient left ventricular dysfunction under severe stress: brain-heart relationship revisited.

PURPOSE: Transient left ventricular dysfunction in patients under emotional or physical stress, also known as tako-tsubo-like left ventricular dysfunction, has been recently been recognized as a distinct clinical entity. The aims of this review are to define this phenomenon and to explore its similarities to the left ventricular dysfunction seen in patients with acute brain injury. METHODS: MEDLINE database, bibliographies of each citation for relevant articles, and consultation with clinical experts were used to examine the clinical picture of tako-tsubo-like left ventricular dysfunction. RESULTS: We identified case series and a systematic review that report on patients with this syndrome. This phenomenon occurs predominantly in female patients, presenting with a variety of ST-T segment changes and mildly elevated cardiac enzymes that mimic an acute coronary syndrome. The left ventricular dysfunction, typically showing a hyperkinetic basal region and an akinetic apical half of the ventricle, occurs in the absence of obstructed epicardial coronary arteries. The ventricular dysfunction usually resolves within weeks with a generally favorable prognosis. This phenomenon has similarities to that seen in patients with acute brain injury with regard to clinical presentation, pathology, and its reversible nature. CONCLUSIONS: Transient left ventricular dysfunction occurs in the absence of obstructive epicardial coronary artery disease. In its broadest sense, this phenomenon may encompass a range of disorders including left ventricular dysfunction after central nervous system injury.

Electrocardiography↗
PubMed2006

Selective renal arterial infusion of fenoldopam for the prevention of contrast-induced nephropathy.

Contrast-induced nephropathy (CIN) remains an important complication of angiographic procedures, particularly among patients with significant renal impairment. To date, vasodilator therapies such as fenoldopam have failed to prevent CIN, possibly because significant hypotension as a result of systemic infusion has limited the ability to deliver adequate drug levels to the renal vasculature. We present a case of averted CIN after multivessel coronary intervention in a diabetic patient with severe renal insufficiency, potentially due to bilateral renal arterial infusion of fenoldopam. Our subsequent experience with intrarenal fenoldopam in nine additional procedures in eight other high risk patients resulted in one case of asymptomatic transient CIN. Further studies are warranted to evaluate the efficacy of intrarenal administration of vasodilator therapies such as fenoldopam for the prevention of CIN.

Acute Kidney Injury↗
PubMed2006

Predictors of recurrent in-stent restenosis after beta-radiation: An analysis from the START 40/20 trial.

OBJECTIVE: The purpose of this study was to identify potential predictors, including clinical, procedural, angiographic, and intravascular ultrasound (IVUS) parameters, for recurrent in-stent restenosis (ISR) following beta-radiation 90Strontium/Yttrium (90Sr/Y) in a large multicenter trial. BACKGROUND: Although adjunct brachytherapy reduces recurrent ISR after primary catheter-based intervention, recurrence of stenosis after brachytherapy still occurs. METHODS: We analyzed 185 IVUS cohort patients in the STent And Restenosis Therapy (START) 40/20 trial where a 40-mm, 90Sr/Y, radioactive source train was exclusively used for treatment of ISR to be treatable with a 20-mm balloon. RESULTS: Thirty-nine patients underwent target lesion revascularization. Preliminary univariate analysis showed that age, smoking, balloon/artery ratio, geographic miss, minimum lumen diameter, and diameter stenosis at baseline were associated with target lesion revascularization, while none of IVUS variables were (minimum lumen area, minimum stent area, or residual plaque burden). The multivariate logistic regression analysis showed that younger age, lower balloon/artery ratio, and presence of geographic miss were independent predictors of target lesion revascularization. CONCLUSIONS: Even with adjunct beta-radiation therapy, initial mechanical optimization, such as appropriate balloon sizing and positioning, may be critical for the prevention of recurrent ISR.

Adult↗
PubMed2006

Safety of beta radiation exposure to the non-target segment: an intravascular ultrasound dosimetric analysis.

BACKGROUND: The use of longer radioactive seed trains to avoid geographic miss may lead to greater radiation exposure to distal vasculature due to the natural tapering of coronary arteries. The aim of this study was to use IVUS-based dosimetric analysis to evaluate the effect of beta-radiation on angiographically normal, noninjured distal segments. METHODS: We analyzed 17 in-stent restenosis cases (stent length: 20 +/- 8 mm) treated with a 40 mm 90Sr/Y source train. The prescribed dose was 18.4 Gy (reference less than or equal to 3.3 mm) or 23 Gy (reference > 3.3 mm) at 2 mm from the source. Noninjured, but fully radiated, distal reference sites were determined by angiography. Based upon the three-dimensional vessel contours obtained at baseline, the minimum dose delivered to 90% of plaque volume (Dv90) was determined. Vessel, plaque and lumen volumes and Dv90 were computed in every 2 mm subsegment (n = 52). RESULTS: On average, no significant serial change was observed in plaque area (5.0 +/- 2.5 mm3/mm post-treatment to 5.6 +/- 3.1 mm3/mm at 8-month follow up; p = 0.09), vessel area (10.2 +/- 3.7 to 10.3 +/- 4.0 mm3/mm; p = 0.84), or lumen area (5.2 +/- 2.0 to 4.7 +/- 1.8 mm3/mm; p = 0.19). Subsegment analysis, however, revealed a wide range of dose distribution, with a significant positive correlation between Dv90 and plaque increase (p = 0.008), as well as vessel change (p < 0.001), representing dose-dependent positive vessel remodeling following beta radiation. Consequently, no significant relationship was observed between Dv90 and lumen change. CONCLUSIONS: Detailed IVUS-based dosimetric analysis demonstrated that beta radiation promoted positive remodeling, preventing lumen loss despite a mild increase in plaque mass on angiographically normal, noninjured distal segments.

Aged↗
PubMed2005

Heterogeneity of neointimal distribution of in-stent restenosis in patients with diabetes mellitus.

Diabetes mellitus is an independent predictor of restenosis after percutaneous coronary intervention. The pattern of restenosis after bare metal stent implantation in diabetic patients was examined with 3-dimensional intravascular ultrasound analysis. Lumen and stent were manually traced at every 0.5-mm interval in stented segments. Using Simpson's method, stent, luminal, and neointimal (stent minus lumen) volumes were calculated and average area was calculated as volume data divided by length. To measure the cross-sectional and longitudinal severities of luminal encroachment by the neointima, percent neointimal area (neointimal area divided by stent area) and neointimal hyperplasia 50 (IH50) (defined as percent stent length with percent neointimal area >50%) were calculated. In 278 patients (68 with diabetes and 210 without diabetes), there was a significantly higher percentage of maximal percent neointimal area with significantly longer percent stent length that was severely encroached by the neointima in diabetic patients. Diabetic patients showed a more heterogenous pattern of the neointima after bare metal stenting, resulting in longer high-grade obstruction segments. This may have important implications for stent design and pharmacokinetic properties of next-generation drug-eluting technology for this complex patient subset.

Aged↗