Retrograde dilatation of chronic total occlusions via collateral vessel in three patients.
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Aged↗
Biomedical subjects
David Meerkin
Publications and source records attributed to David Meerkin.
My buddy, my friend: focused force angioplasty using the buddy wire technique in an inadequately expanded stent.
Progressive minituarization of angioplasty hardware has resulted in a reduction of access site complications. This has limited to some degree the equipment used with small delivery systems. The buddy wire technique is a potential solution for resistant lesions with an underexpanded stent that can be used without having to upsize the introducer and guiding catheter.
Angioplasty, Balloon, Coronary↗
Renal fractional flow reserve: a hemodynamic evaluation of moderate renal artery stenoses.
The objective of this study was to perform a hemodynamic evaluation of moderate (50-90%) renal artery stenosis (RAS) under conditions of rest and maximum hyperemia. Identifying patients with RAS who have hemodynamically significant stenoses and are most likely to benefit from revascularization is clinically important. Current methods used to evaluate RAS, including angiography, have limitations. Physiologic evaluation of RAS may have a role in identifying patients with hemodynamically significant stenosis. Patients with suspected renovascular hypertension due to aorto-ostial RAS were included in the study. Hyperemia was induced by administration of intrarenal papavarine. Translesional pressure gradients were measured and renal fractional flow reserve (FFR) was calculated using a 0.014'' pressure guidewire. Thirteen patients and 14 arteries with moderately severe (50-90%) RAS were studied. The mean translesional pressure gradient rose from a baseline of 6.3 +/- 3.9 to 17.5 +/- 10.8 mm Hg with maximal hyperemia. The renal FFR ranged from 0.58 to 0.95. There was a poor correlation between angiographic stenosis measurement and the renal FFR (r = -0.18; P = 0.54) and the hyperemic translesional mean pressure gradient (r = 0.22; P = 0.44). There was an excellent correlation between renal FFR and the resting mean translesional pressure gradient (r = -0.76; P = 0.0016) and the hyperemic mean translesional pressure gradient (r = -0.94; P < 0.0001). Selective renal arterial papavarine administration induces maximum hyperemia, permitting the calculation of renal FFR in renal arteries with aorto-ostial stenoses. The renal FFR correlates well with other hemodynamic parameters of lesion severity, but poorly with angiographic measures of lesion severity.
Aged↗
Effects of focused force angioplasty: pre-clinical experience and clinical confirmation.
Balloon angioplasty results in a combination of plaque compression and fracture, creation of intimal flaps and localized medial dissection, as well as the stretching and remodeling of the arterial wall. The application of eccentric pressure to the vessel wall allows for the balloon force to be focused along a specified line resulting in a reduction in vessel resistance with an improved or equivalent result at a lower pressure. The FX miniRAIL is a novel balloon angioplasty catheter that has two external wires that are compressed by the inflating balloon into the vessel wall. It was tested in comparison to conventional balloon injury in a porcine coronary model. At equivalent balloon artery ratios no increase in the length of dissections occurred, but a characteristic longitudinal "cut" was noted in the presence of the FX miniRAIL. A similar finding was demonstrated in sample human cases when interrogated by IVUS and OCT.
Angioplasty, Balloon, Coronary↗
Giant aneurysm of a tiny coronary branch.
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Aged↗
Distal protection of bifurcating vessels: a novel approach.
Distal protection devices protect only a single distal vessel. We describe a novel technique to protect both branches following a thrombus-containing bifurcation lesion. The combination of an occlusive balloon and an arterial filter system provides an attractive solution to the challenging environment of a lesion at high risk for distal embolization supplying more than a single major branch.
Angioplasty, Balloon, Coronary↗
Rofecoxib, a COX-2 inhibitor, lowers C-reactive protein and interleukin-6 levels in patients with acute coronary syndromes.
BACKGROUND: Patients with acute coronary syndromes (ACS) have high levels of inflammatory mediators such as C-reactive protein (CRP) and interleukin (IL)-6. AIM: To evaluate whether patients with ACS treated with rofecoxib, a COX-2 inhibitor, will have reduced CRP, IL-6, and soluble tumor necrotic factor receptor-1 (sTNF-R1) levels and improved endothelial function. METHODS AND RESULTS: Thirty-four patients hospitalized with ACS were randomized to receive rofecoxib, 25 mg/d plus aspirin 100 mg/d, or placebo plus aspirin, 100 mg/d, for a period of 3 months. Blood samples for CRP, IL-6, and sTNF-R1 levels were drawn prior to randomization, and after 1 month and 3 months. CRP levels in the rofecoxib group (n = 18) were significantly lower both at 1 month and 3 months compared to the baseline levels (p < 0.02). IL-6 levels were significantly lower at 1 month (p < 0.02) in the rofecoxib group, but not at 3 months. There was no change in endothelial function or sTNF-R1 levels. CONCLUSION: Patients recovering from ACS had lower levels of CRP and IL-6 at 1 month and lower CRP levels at 3 months when treated with rofecoxib plus aspirin. Suppression of inflammatory processes may lead to retardation of coronary atherosclerosis and coronary events.
Acute Disease↗
Intracoronary brachytherapy for the prevention of restenosis after percutaneous coronary revascularization.
PURPOSE: The purpose of this article is to review the current literature pertaining to intracoronary brachytherapy for the prevention of restenosis after percutaneous coronary revascularization (PCR). METHODS: English-language articles were identified through a MEDLINE search (January 1984 to January 2003) using the keywords brachytherapy, radioactive stents, and coronary arteries. In addition, pertinent reference citations from relevant articles were reviewed. RESULTS: Restenosis after PCR is a complex process, thought to be due to a combination of vessel wall remodeling and neointimal proliferation. To date, catheter-based delivery of intracoronary brachytherapy has been found to prevent vessel wall remodeling and causes a reduction in the proliferation of the neointima. Neointimal proliferation, as measured by mean neointimal area, was reduced in all animal studies (range 26%-91%). In contrast, animal studies examining radioactive stents demonstrated an increase in neointimal proliferation, suggesting that they may not be helpful at preventing post-PCR restenosis. All human studies using catheter-based intracoronary brachytherapy for in-stent restenosis have employed either beta (beta) or gamma (gamma) radiation sources with variable doses of radiation (range 7-56 Grays [Gy]). Restenosis occurred in 12% to 40% of patients in nonrandomized studies, and clinical events occurred in 13% to 50% of patients. To date, there have been 7 published randomized trials in humans comparing catheter-based intracoronary brachytherapy to placebo, with a total of 1047 patients. The dose of radiation in the trials ranged from 14 Gy to 30 Gy. During follow-up, 8% to 33% of patients who received brachytherapy had restenosis versus 39% to 64% of patients receiving placebo. Clinical events occurred in 19% to 50% among patients who received brachytherapy versus 29% to 79% among patients receiving placebo. The majority of human studies examining radioactive stents do not demonstrate a reduction in restenosis in patients post-PCR. There are no randomized trials examining radioactive stents in humans. CONCLUSION: Nonrandomized studies of radioactive stents suggest they are not effective at preventing in-stent restenosis. In contrast, data from animal and human studies suggest that catheter-based intracoronary brachytherapy can prevent in-stent restenosis and reduce clinical events post-PCR.
Angioplasty, Balloon, Coronary↗
Results of coronary artery stenting in women versus men: a single center experience.
BACKGROUND: Prior studies have suggested that women are at higher risk for morbidity and mortality during coronary angioplasty, although long-term prognosis is similar after successful procedures. OBJECTIVES: To examine the role of gender in coronary stenting, including immediate procedural success as well as early and late outcomes. METHODS: The study group comprised 560 consecutive patients (119 women and 441 men) who had undergone stenting over a 3 year period. RESULTS: The indications for coronary stenting were similar among women and men, and stents were successfully deployed at similar rates without complications (92 vs. 90% respectively). Cardiac death or myocardial infarction within 30 days of the procedure was observed in 5% of women and men, whereas none of the women, compared to 1.4% of men, had early revascularization. Bleeding complications occurred in 4% of women and 2% of men. During 10 +/- 2.8 months of follow-up, 58% of women and men underwent repeat cardiac catheterization, revealing similar rates of restenosis, 36 vs. 32% respectively. During the study period, 3.3% of women as compared to 0.9% of men had a cardiac death (not significant). Cardiac death or myocardial infarction was observed in 7% of women and 8% of men, and the combined endpoint of death, myocardial infarction or revascularization, was noted in 24% and 26% respectively. Multivariate Cox analyses of the clinical, angiographic and procedural characteristics revealed that multiple stent deployment was the only predictor of major adverse cardiac event among men, whereas none of these characteristics predicted outcome in women. CONCLUSION: Coronary stenting is performed with similar success rates among women and men, with similar restenosis rates as well as early and late major adverse cardiac events.
Aged↗
Benefits of cutting balloon before stenting cut and stent.
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Atherectomy, Coronary↗
Two-year angiographic follow-up of intracoronary Sr90 therapy for restenosis prevention after balloon angioplasty.
BACKGROUND: Postcoronary angioplasty vascular brachytherapy (VBT) has emerged as a successful intervention for restenosis prevention in some clinical scenarios. Longer-term follow-up after VBT in de novo nonstented lesions has not been reported. METHODS AND RESULTS: Thirty patients treated with post-percutaneous transluminal coronary angioplasty (PTCA) VBT with Sr90 underwent clinical and angiographic follow-up at 6 and 24 months. Specific vessel segment quantitative coronary angiographic analyses were performed to identify radiation edge effects. Nineteen patients who had not undergone index procedure stenting or target vessel revascularization (TVR) over the 2-year period were analyzed separately. Of the 30 patients, 3 underwent TVR by 6-month follow-up. An additional 4 patients required TVR between 6 and 24 months. In the total cohort of 26 patients undergoing angiographic follow-up at 6 and 24 months, an increase in minimal lumen diameter of the initial target segment was noted at 6 months compared with postprocedure analysis (2.31+/-0.48 versus 2.04+/-0.43 mm, P<0.05). At 24 months, this was no longer significant (2.19+/-0.61 mm). In the proximal segments of the entire cohort and the nonintervened subgroup, the principal late loss occurred over the first 6 months with no additional late loss at 2-year follow-up. The distal segments remained stable over the entire follow-up period. CONCLUSIONS: Although some late failures of post-PTCA VBT are seen between 6 and 24 months, most treated vessels remain stable with no late loss or additional luminal increase beyond the 6-month period. This suggests that late aneurysm formation and significant late edge restenosis are unlikely in VBT after PTCA of de novo lesions for up to 2 years.
Angioplasty, Balloon, Coronary↗
Transmyocardial coil implants: a novel approach to transmyocardial revascularization.
BACKGROUND: Transmyocardial laser revascularization (TMLR) has potential benefit for patients with end-stage coronary artery disease and intractable angina not amenable to conventional revascularization techniques. Neovascularization has been proposed to occur around the laser channels. Our aim was to determine the feasibility of a novel nonlaser myocardial revascularization technique and its effect on angiogenesis in a nonischemic porcine model. METHODS: In the first phase, six transmyocardial stainless steel coil implants (TMI) were deployed to the lateral wall of the left ventricle in each of 6 pigs. The animals were sacrificed at 8 and 12 weeks, with a single animal dying prematurely at 4 weeks, and the myocardium was assessed for new vessel growth. In the second phase, 8 implants were deployed in each of 12 pigs with regular fluoroscopic follow-up until sacrifice at 2 weeks to assess implant stability. RESULTS: The deployment procedure was safe and feasible with no complications evident. A significant increase in new vessels at implant sites with 5.43 +/- 3.67, 4.97 +/- 2.44, and 3.57 +/- 2.29 seen per high power field at 12, 8, and 4 weeks, respectively, compared to 1.00 +/- 1.06 (p < 0.0001) in control myocardium. There was no evidence of implant migration in Phase 2. CONCLUSIONS: TMIs can feasibly be deployed in the nonischemic pig model with a high success rate. The presence of angiogenesis at the implant site and the maintenance of this reaction for 3 months implies that TMI may offer an alternative to TMLR while providing a platform for delivery of angiogenic factors.
Animals↗
Cutting and stenting in a heavily calcified left anterior descending artery lesion.
The significance of heavily calcified proximal left anterior descending coronary artery stenosis in a 57-year-old man was assessed physiologically using a Doppler flow wire. Intravascular ultrasound guidance allowed for adequate dilatation with a cutting balloon and optimization of stent deployment. The cutting balloon offers an effective alternative in this challenging scenario.
Arteries↗
Provisional bifurcation stenting.
Obstructive coronary lesions involving a branch origin or extending into the branch itself, remain one of the main challenges in the rapidly developing world of interventional cardiology. Acutely, these lesions are prone to the complications resulting in significant residual stenosis or loss of one of the branches. Long-term follow up has also been disappointing with a high incidence of restenosis. Numerous techniques have been developed, aimed at optimizing the acute and long-term results by adapting standard angioplasty hardware, with limited success, particularly in the long term. This article describes a fully dedicated system for bifurcation lesions with stenting of the main vessel to the main branch, yet ensuring side branch patency, with limited risk of branch origin stenosis or stent jailing, allowing for provisional stenting of the branch as dictated by the angiographic outcome.
Journal Article↗